NICFOLLS’S
SEAMANSHIP AND NAUTICAL KNOWLEDGE
WheelHonse Eq mpxxLpiit.
NICHOLLS’S
Seamanship and
Nautical Knowledge
Second Mates’,
Examinations
BY
CHARLES H. BROWN, F.R.S.G.S.
Superintendent ( retired)
School of Navigation, Royal Technical College, Glasgow
Extra Master Passed tn Steam
Ftyst-class Honours Navigation t Nautical and Spherical Astronomy;
Advanced Naval Architecture and Matkematics, Board of
Education , South Kensington
, , BROWN, SON & -FERGUSON, Ltd., Nautical Publishers
52 to 58 Dabnlby Street
18 th Edition
Reprinted
99
- - 1938
- - 1939
1940
April, 1941
November, 1941
June, 1942
June, 1943
March, 1944
March, 1945
January, 1946
January, 1947
March, 1948
Made coed Printed in Great Britain by
Brown, Son & Ferguson, Ltd , Glasgow, S.l.
PREFACE.
It is not easy to define the scope of modern academic seamanship as it
me u es within its limits more than a passing knowledge of mechanics
and physics; the Merchant Shipping Act and Statutory Regulations as'
affecting ships, cargoes and seamen; the structure of the vessel, her
stability, equipment, internal organisation and mobility; the convey¬
ance of cargoes and the working of the ship as an economic unit,
together with a general knowledge of many nautical things which the
seamen may never be called upon to exercise in practice.
The ideal seaman is he who says and does the proper thing in just
the proper way and at the proper time, a man who has developed sea
sense and nautical sagacity. But ideal conditions and the ideal m an
seldom, if ever, confront each other in an emergency at sea.
No man can hope to acquire a full and complete knowledge of all
nautical subjects either from the personal experiences of a lifptimo or
from a prolonged reading of textbooks, but the prudent seaman reads
every shipping publication that comes his way, takes reasonable
precautions and studies the ways of ships and men, visualises possible
contingencies and mentally decides what action he would take in the
event of sudden emergency.
We flo not pretend to have treated any of the subjects exhaustively;
the student who wishes to specialise must refer to recognised textbooks
written by experts. We have aimed, rather, at a simple introduction
of several aspects of seamanship, referring to fundamental principles in
cases where such exist, and developing the several themes up to a
reasonable examination standard. There is not a clear demarcation in
the Board of Trade syllabuses between the amount of knowledge
required for the several grades but, obviously. Masters are expected to
have a fuller and more intimate knowledge of various things than First
Mates, and First Mates than Second Mates, so it behoves the beginner
to assimilate as much information as his experience and capacity will
admit.
Much of the candidate ’s kno wledge is pure memory work—Statutory
Regulations, for example—devised, mainly, to bring about uniformity
PREFACE
of practice, and a knowledge of these can only be acquired by trequent
reference and repetition, hence the reason why some of the information
is conveyed in the form of Questions and Answers.
We have drawn largely on the experience of others as their
knowledge has enabled us to collate the varied information which forms
the basis of the Board of Trade Oral Examinations for Certificates of
Competency as Second Mates, Mates and Masters.
I am indebted to numerous friends and colleagues for advice and
guidance in the preparation of this work and gratefully acknowledge
their assistance, also the kindness of many firms in granting permission
to reproduce illustrations from their publications, and particularly to
Mr. William M. Gray, B.Sc., M.I.N.A., for criticism and many of the
drawings which illustrate the chapter on Ship Construction, also to—
Messrs. Allan Whyte & Co., Glasgow Wire Hope Manufacturers.
Brassey's Naval Annual .
The British Mahnesmann Tube Co., London. Derricks.
Messrs. Brown, Lennox & Co., London. Anchors, Cables and
Buoys.
Messrs. Bruntons (Musselburgh), Ltd., Musselburgh Wire Ropes.
Messrs. The Bergius Co., Ltd., Glasgow. Kelvin Motor Engines.
Messrs. Chadbum’s (Ship) Telegraph Co., Ltd., Liverpool. Ship
Telegraphs.
Messrs. Davey & Co., London. Blocks and Tackles.
The Electric Submerged Log Co., London.
Messrs. Emerson, Walker Ltd., Gateshead-on-Tyne. Steam
Capstans and Windlasses.
Messrs. Haslam & Newton, Ltd., Derby. Refrigerating Plant.
Messrs. Henry Hughes & Son, Ltd., London. Echo Sounding
Machines.
Messrs. John Hastie & Co., Greenock. Steering Engines.
The Imperial Merchant Service Guild. Forrest’s Jury Rudder.
The Radio Communication Co., Ltd., London. Direction Finders.
Messrs. Kelvin, Bottomley & Baird, Ltd., Glasgow. Sounding
Machines? Pneumercatox Tank and Draught Gauges.
PREFACE
Messrs. New Zealand Shipping Company, London.
Shipbuilding and Shipping Record.
The Shermuly Pistol Rocket Apparatus, Ltd., London, Line-
Throwing Gun.
Messrs. Sliding Hatch Beams (“T&B” Patents) Ltd., London.
Messrs. Stewarts & Lloyds, Ltd., Glasgow. Tubular Davits,
Messrs. J. Stone & Co., Ltd., London. Hydraulic Watertight
Bulkhead Doors.
The Submarine Boat Corporation, Newark, N.J. Shipyard
Illustrations.
Messrs. Taylor, Pallister & Co., Ltd., Dunston-on-Tyne.
The “ Dunstos 55 Patent Rudder Brake.
Messrs. Wehn &Co., London, and Messrs. Welin-Maclachlan Davits
Ltd., Glasgow. Boat Davits and Gear,
The Yachting World.
NOTE.
Where “Board of Trade” is referred to in this book substitute
“Ministry of Transport 55 which is now responsible for legislation
formerly administered by the Marine Department, Board of Trade.
CONTENTS.
CHAPTER I.
The Division of the Day at Sea—Helm Orders—Conning the Ship
—Sailing Ship Rigs—Types of Steam Vessels—Sailing Ship
—Square Sails .. .. . 1
CHAPTER II.—KNOTS AM) SPLICES.
Knots, Hitches, Bends and Splices—Wire Splicing—Blocks—Purchases
and Mechanical Advantage .. .. .. .. .. .. 8
CHAPTER III.—ROPES AND PURCHASES.
Strength of Ropes, Wire and Manila—How to Handle Wire Rope—
Strength of Cham—Theoretical Advantage of Tackles—Test
Loads on Derricks—Questions. 34
CHAPTER IV.—STEAMSHIPS* MASTS, SAILS AND DERRICKS
Rigging of Steamships—Standing Rigging—Fitted and Telescopic
Topmasts—Sending Topmasts up and Down—Sending down a
Signal Yard—Rigging Derricks—Steamships' Sails—Bending,
Setting, and Taking in Trysails and Staysail—Parts of a Sail .. 49
CHAPTER V.—BOAT SAILING.
•
Ships' Lifeboats—Standing and Dipping Lugsails—Terms used when
Sailing a Boat—Boat Sailing and her Management in Heavy
Weather—Sailing Ship Rule of the Road .. .. *. .. 66
CHAPTER VI.—BOAT CONSTRUCTION AND EQUIPMENT.
Ships' Boats—Lowering and Hoisting Boats—Davits, Radial, Quadrant
and Gravity Types—The Motor Launch—Marine Motor Engines
—Manoeuvring the Launch—Steamboat Rule of the Road—
< Effect of Oil on Waves—Construction of Ships' Boats—Boat
Equipment—Types of Boats, their Capacity, Buoyancy, Marking,
etc.—Life-Saving Appliances, Boats, Davits, Life-buoys, Life¬
belts, etc.—Boat Stations and Drill .• * - - • • • 63
* CHAPTER VII.—ANCHORS AND CABLES.
Parts of an Anchor—Bow Stoppers—Mooring Anchors—Chain Cables
< ^ and Shacktes—Anchors and Chain Cables Act . - * - 116
CONTENTS
CHAPTER VIII.—DECK APPLIANCES AND APPARATUS
Telegraphs—Lead Line—Patent Sounding Machines—Echo Sounding
Machine—The Common Log—Patent Logs—Electrical Ship
Log—Speed of the Propeller—Fuel Consumption and Speed—
Meteorological Instruments—Barometer and Vernier—Aneroid—
Barograph—Thermometer Scales—Maximum and Minimum
Thermometers—Hygrometer—Ram Gauge—Radio Direction
Finder—Sluices and Watertight Doors—Steering Gears, Hand-
gear, Steam and Telemotor Steering Engines—Emergency
Steering Gear—Deck Winches and Capstans—Windlass—Steam
Boilers—Reciprocating and Turbine Marine Engines—Motor
Ship—Fire Extinguishing Appliances, Water, Steam and Chemical
Systems—Portable and Fixed Extinguishers—Precautions to Pre¬
vent Fire—Steps to be taken in the Event of Fire—Board of
Trade Regulations regarding Fire Extinguishing Apparatus—
Fire Drill and Muster Lists—Standmg Rules for Steam Vessels
at Sea, in Port and at Anchor—Questions .. .. .. 124
CHAPTER IX—REGULATIONS FOR PREVENTING COLLISION
AT SEA.
Articles 1 to 16—Ships' Lights and Fog Signals—Recognition of Lights—
Questions and Answers on Contents of Articles .. .. .. 183
CHAPTER X.—STEERING AND SAILING RULES.
Articles 17 to 31—Rule of the Road—Questions and Answers on Contents
of Articles—To Find out How a Vessel is Heading at Night—
Diagrams relating to Rule of the Road .. .. .. .. 206
CHAPTER XI —NOTICES TO MARINERS, ETC.
Closing of Ports—Mine-sweeping Operations—Aircraft Signals—
Salvage of Torpedoes—Lightvessels—^Navigating Stem Foremost
‘ —Seine Net Fishing Boats—Uniform System of Buoyage—
Wreck-marking Signals—Fog Signal Apparatus—Life-saving
Service—Visual and Sound Signals—Mortar and Rocket Appara¬
tus—Lme-throwing Appliances—Ships’ Bells, Whistles and Fog¬
horns—Screening of the Navigation Lights—Questions. * .. 2&8
CHAPTER XII-—PARALLELOGRAM OF FORCES.
Examples—A Canal Boat—Current Sailing—Moorings—Action of the
- Rudder and Turning Circle-—T^rue and Apparent Wind—Boat
Sailing—Cargo Spans—Derricks—Questions .. .. .. 263
CHAPTER XIII.—SCREW RACE AND SHIP HANDLING.
The Wake Current—The Transverse Thrust—The Screw Race—Effect ,
with Headway, Stemway, and at Starting—Twin Screws—
Turning Circle—Ship Handling—Anchoring, Mooring and
Berthing—Tending Ship at Anchor—Getting under way—Emer¬
gencies—Accidents—Jury Gear—Towing—Ship's Log Book .. 287
CONTENTS
CHAPTER XIV—MENSURATION.
Weights and Measures—Areas and Volume^—Stowage Factors—
Simpson's Rules—Examples .. .. .. .. .. 343
, CHAPTER XV.—HYDROSTATICS.
The Hydrometer—Buoyancy—Water Pressure—Atmospheric Sounding
Tube—Tank Pressure Gauges—Draught Indicator—Markings
on a Ship—Variations in Density and Draughty-Load Lines for
Sailing Ships, Cargo Steamers, Tankers and Timber Laden
Steamers—Zones and Seasonal Areas—The Load Line—Headmgs
of the Official Log—Questions .. .. .. .. *. 359
CHAPTER XVT.—CARGO.
Cargo Gear—Factory and Workshops Act—Dunnage—Homogeneous
Cargoes, Coal, Ore, Grain, Rice—Stowage of Various Cargoes—
Questions and Answers—Dangerous Cargoes—Details of Grain—
Oil and Timber Cargoes—Frozen and Chilled Cargoes, Meat,
Fruit, etc.—Bulk Oil—Cargo Plan—Questions .. .. .. 388
CHAPTER XVII —SHIP CONSTRUCTION.
The Stresses on a Ship: Longitudinal, Transverse, Racking, Collapsing,
Bulging—Local Stresses—A Transverse Section: Frames, Floors,
Beams, Pillars—Longitudinal Framing: Keels, Keelsons,
Stringers, Ballast Tanks, Cellular Double Bottoms—Web Frames
and Stringers, Rivets and Riveting—Shell and Deck Plating—
Butts, Laps and Landings—Deck Planking—Beam Knees—
Pillars—Watertight Flats—Bulkheads—D*eep Tanks—Hatch¬
ways and Coamings—Panting Arrangements—Stem Framing—
Rudders—Shipyard Photographs—The Stem Tube—Twin Screw
Struts—Pipe-Lines, Suction and Sounding Pipes—Ventilation—
Isherwood Ships—Corrosion—Paint—Bottom Compositions—
Numerals for Scantlings—Questions . / .. .. .. 426
CHAPTER XVIII.—STABILITY, CARGO AND TR&I.
Levers—Parallel Forces and Principle of Moments—The Wheel and Axle
—A Couple—Centre of Gravity of a System of Weights—
Various Distributions of Weights—Equilibrium, Stable, Neutral
and ‘Stable—Displacement, Tonnage and Volume—Coefficient
of Fineness—Ship Stability—Metacentre—The Heeling Ex¬
periment—Ship Graphs: Curves of Displacement* Tons per Inch
Immersion, Stability, Buoyancy and Metacentre—Cargo and
Stability—Cargo Plan—Cargo and Trim—Examples and Calcula¬
tions—Questions
CHAPTER XIX.—REGISTRATION OF SHIPS AND SEAMEN.
The Board of ’I'rade—Customs and Excise—Ministry of Health—Port
and Local Authorities—Classification Societies—His Majesty’s
Stationery Office a^d Marine Publications—The New Ship—
Launching—Certificate of Registry—-Certificates under the
488
CONTENTS
Anchor and Chain Cables Act, Freeboard and Load Line,
Life Saving Appliances, Safety Radio Telegraphy Certificates—
Master’s and Crew Spaces—Lifeboatmen's Certificates—Panama
and Suez Canal Certificates—Declaration of Health—De-
ratisation of Ships—Hygiene—National Health Insurance—
Animal (Sea Transport) Order—Factory and Workshops Act—
Classification Surveys—Engagement and Discharge of Crew—
Official Log. 538
CHAPTER XX.—SHIP’S BUSINESS.
Particular and General Average—York-An twerp Rules—Bill of Ex¬
change—Bill of Lading—Charter Party—Entering and Clearing
at Custom House—Protest—Survey—Pilot—Ship's Papers .. 579
CHAPTER XXI.—MISCELLANEOUS.
Rope—Paint—Drydocking—Drawings, Freeing Port, Ventilator, Strum
Box, Deep Tank Top, Cellular Double Bottom, Stringer, Web
Frame, Watertight Flat, Hatch Coaming .. ' .. .. 597
CHAPTER XXII.—SIGNALLING.
The International Code of Flags—One, Two, Three and Four Flag •
Signals—Alphabetical and Numeral Signals—Instructions How
to Signal—Notes on Signalling—Distant, Semaphore and Morse
Signalling—Questions and Answers . 619
SYLLABUSES.
We give here the Ministry of Transport Examination Syllabuses for all
grades and have inserted Roman Numerals against the paragraphs
to indicate the chapters in this book where reference is made to
the subjects named, with the exception of “ Engineering Knowledge,”
which has not been referred to.
The Syllabuses of the Merchant Navy Training Board which, in
effect is similar to that of the Ministry of Shipping for Second
Mate Certificates, is also given for each year of apprenticeship,
but re-arranged to meet the order of presentation adopted in
this text-book, together with the pagings of the various items
for convenience of reference to facilitate the work of instructors
and of students at sea.
Specimen examination papers are given at the end of the book.
SECOND MATE (FOREIGN-GOING).
35. General.— Candidates should demonstrate their unders t andin g of
their work by means of sketches and figures drawn with reasonable accuracy
but not to scale.
The “Knowledge of Principles” paper is intended to test the candidate's
grasp of fundamental technical ideas and processes required in his work at
sea Mathematical proofs of formulae are not required, but a candidate
should be able to demonstrate the truth of a formula by means of a figure,
where possible.
36. Paper 1.
Knowledge of Principles.
{3 hours.)
The reading of simple graphical diagrams, e.g. r stability curves, y
statistics, etc. (XVIII.) Also Chapter HI., Volume I., Nichola s Guu
. weather
Guide.
fc) Areas and perimeters of rectangle, triangle, circle* volumes, and surface
areas of box-shaped bodies, cylinders and wedges Practical applications,
e e weight of general cargo of varied shapes; capacities of holds and bunkers;
iigWSSti of bunkers. (XTvT Also Chapter IV., Volume I.,
Nitidis*$ Guide .
Trigonometrical rafcio^ine, cosine, tangent, cosecant, secint,
co-raogent, baversme.
REGULATIONS
The simple relations between these ratios. The relation between the ratios
01 angles which together make (a) one right angle, (6) two right angles, e.g.,
the sine of an angle — the cosine of its complement, etc Chapter VI.,
Volume I., Ntcholls*s Guide
40. Paper 5. Cargo Work and Elementary Ship Construction. (3 hours."
(a) The stowage and dunnaging of different varieties of cargoes, including
bulk cargoes. Elementary ideas on the making and use of cargo plans
The preparation for stowage, breaking out and discharge of cargo
Rigging a ship for loading and discharging cargo, and the use of derricks
and winches. Strength of cargo gear.
The calculation of capacities of bunkers, holds, tanks and boats.
Calculation of capacities taken up by part cargoes and of space remaining.
Conversion of weight measurement of cargo into space measurement and
vice versa. (Ill , IV , XIV , XVI )
(i>) The names of the principal parts of a ship
General ideas on ship construction and hull maintenance.
The candidate will be expected to show his practical acquaintance with
certain portions of his own ship, e g. longitudinal and transverse framing
Bulkheads. Hatches. Rudders and steering gear. Shell plating. Stern
frame Propellers and propeller shafts, stern tube, propeller brackets.
The stiffening and strengthening to resist panting, pounding and propeller
vibrations
Double bottom tanks, bilges, bilge pumps, sounding pipes Ventilation
systems of holds and tanks (XVII)
(c) Displacement Deadweight.
Use of tons per inch immersion scale. Calculation of weight of cargo, etc.,
from draughts.
Effect of varying density of water.
Buoyancy. Centre of gravity and centre of buoyancy. The laws of
floating bodies.
Effect of filling and emptying ballast tanks on centre of gravity of ship as.
a whole. (XVIII)
41. Paper 6 . English. (1J hours.)
The paper will be designed to test the candidate's ability to write clear
and grammatical English with due attention to spelling and penmanship.
It will be in no sense a test of technical knowledge.
42. Oral and Practical Portions.
1. — (a) Rigging of ships. Strength of ropes, wire and hemp. Rigging
purchases of various kinds and knowledge of power gained by purchases
Knotting and splicing hemp and steel ropes with strict reference to current
practice. Seizings, racking, chain stoppers, etc.
(b) Sending topmasts up and down.
(c) Bending, setting and taking in fore and aft sails. Management of
boats under oars and sail and in heavy weatner. Beaching or landing
Coming alongside.
{d) Helm orders. Conning the ship. (I. to VT )
2. —(a) Marking and use of ordinary lead line.
(b) Use and upkeep of mechanical logs and sounding machines*
(o) Use and upkeep of engine room and other telegraphs.
(d) Rocket and line throwing apparatus. (VIII., XI.)
3. —(a) Anchors and cables. * Use, upkeep and survey.
lb) Knowledge of use and maintenance of deck appliances and steering
{c) Fire extinguishing apparatus—steam, chemical and other appliances.
0 ii., vm., xi.) r
REGULATIONS
4 — (a) Preparations and precautions for getting under way Duties prior
to proceeding to sea, making harbour or coming alongside, especially at after
end of ship.
(b) Keeping an anchor watch. Dragging anchor.
(c) Duties of officer of the watch. Use of compass to ascertain risk
of collision. (VIII , XIII )
5. —( a) A full knowledge of the content and application of the Regulations
for Preventing Collision at Sea (Candidates will not be placed in the position
of handling a sailing ship, but will be expected to recognise a sailing ship’s
lights and to have a knowledge of her possible manoeuvres according to the
direqtion of the wind )
(b) Distress and pilot signals, penalties for misuse
(c) British umform system of buoyage.
( d) An intelligent use of “ Notices to Manners ” (Candidates will not be
required to commit these to memory ) (IX., X , XI.)
6. —Signals
To send and receive signals in*—
(a) Bntish Semaphore up to eight words per minute.
(h) Morse Code by flash lamp up to six words per minute.
(c) International Code of Signals (XIX )
7. Practical
(a) To read and understand a barometer, thermometer, hydrometer and
hygrometer. (The instruments supplied by the Meteorological Office will
be taken as standard.)
(b) To use an azimuth mirror, pelorus (bearing plate) or other instrument
for taking bearings, to place these bearings on a chart, having corrected for
given compass error
(c) To use a sextant for taking vertical and horizontal angles; to read a
sextant both on and off the arc
( d) To correct a sextant into which has been introduced some or all of
perpendicularity, side and index errors
(e) To find the index error of a given sextant.
(f) To check chronometers by signal made by buzzer or other method, to
compare' two chronometers. (VIII) Also Chapters XII., XIII , Volume I ,
Nichotts’s Guide.
8. —The Examiner may ask the candidate questions arising out of the
written work, if he deems it necessary on account of weakness shown by the
candidate (This applies particularly to Paper 5.)
FIRST MATE (FOREIGN-GOING).
48. Paper 4 (Written.) Ship Construction and Stability. (3 hours)
(a) A general knowledge of the principal structural members of a ship.
Midship sections of different types of ships, giving the parts their proper
names Scaling dimensions on a midship section to make intelligible reports.
Ability to set out in a clear manner a report on damage sustained by
corrosion or by accident.
Construction and stiffening of watertight bulkheads.
Collision bulkhead.
Stem frame and stem and how secured.
Stresses and strains in ships through effect of seas or loading and ballasting.
A knowledge of those portions of a ship specially strengthened to
withstand such stresses, or where excessive damage by corrosion is liable to
^Irivets and rivetings Testing a line of rivets Testing watertight work.
Rudders and steering gear. Inspection and maintenance.
Hatches and hatch gear. Hawsepipes and cable lockers.
(fy ^Buoyancy and reserve buoyancy. The righting couple when a ship
regulations
2 i? c i' Iled -, Metacentre and metacentnc height Transverse and longi-
cu-fwfi. m ®^ acen * res - stifi and tender ships—how to obtain stiffness
Stability at large angles of inclination and what this depends on
particu?arSondit°on data ** ascertamm § metacentnc heights of a ship m any
of of C j n L tre ° f gravity of a ship in any condition, the centre
K ght c °“ dltl ° n bem 8 given. Use of stability curves and data
ca^o'^Chige'of tnri^^fXVn* a Effect of shifting*
49. Papers. (Wntten) Ship Maintenance, Routine and Cargo Work. ( 3 ,hrs.)
(a) Keeping a ship’s log. (Mate’s log.)
J 6) f^P maintenance and organisation. Indents and stores. Repair
Properties and uses of paints Painting Chipping, scraping. Cement
T or ?\ Treatment of wood work. Inspection and maintenance of bulkheads
double bottoms, deep tanks, rudders. Bottom painting. Dramaee of holds
and double bottom tanks. Inspection and maintenance ofaflhors and
cables Maintenance of holds with reference to cargo carrying. Spar ceilings
te *° s P ecbon artd maintenance of pumps, strums, roseboxes^and bilges.
calcul ^ bo11 °f stresses m spans, derricks, toppmg lifts etc
poweSi^edT pum^ses. gS> ^ ^ at “ etc ' Purc hases and
ansits^m e^eri^ 6 P ° SSible ’ dlustrate
Stowage of cargo General—stowage of bag cargoes, bales casks etc
S ‘"“ 1 =^oe Mwte , lv , Si timber. „d „
Given a cargo list, to stow a hold or holds, making a rough cargo plan
Methods of ventilation of cargoes. Drainage of holds.
•-S^S^E &VKTS8LSS5sf
51. Oral Portion.
Shifting large spars and nggmg sheers;
gear Ls^ ^ °* heaVy Weigbts -Pedal reference to strength of
■sjyrsr si
spadeTl>mesinc- anchor a v ** 30 !; m a Weway and in a confined
* Gettti^ under way. to ^opt
'MM&vk of propellers on tb#* ? 1 *
i Eieet of propellers on the steering of V
tjrtooenvnng. Turning circles/ l^ec^
Stopping, going
Current win/-? sea.
REGULATIONS
(b) Coming alongside a wharf, etc. Turning a steamship short round}
manoeuvring m nvers and harbours Emergency manoeuvres. Man
overboard.
{c) Management of steamships m stormy weather
(d) To get a cast of the deep sea lead. (VIII , XIII)
4. —(a) Testing life-buoys and life-jackets, other life-safang gear.
(b) Accidents, e g , collision, running aground, accidents to hatches, leaks,
fires and their treatment. Running repairs Handling a disabled ship.
(c) A practical knowledge of the screenmg of ships' navigation lights
(d) Preparation for dry-docking Use of shores, bilge blocks and bilge
shores. (VI , VIII , XI, XIII)
5. — Regulations for Prevention of Collision at Sea. —As par. 42, Section 5
(Oral), Second Mate (IX , X , XI) ♦
6. —Signals.—As par 42, Section 6 (Oral), Second Mate. (XIX)
7. —The Examiner may ask the candidate questions arising out of the
written work, if he deems it necessary on account of weakness shown by the
candidate.
MASTER (FOREIGN-GOING).
55. Paper 3. (Written) Ship Construction and Stability. (3 hours.)
(a) The direction of simple ship repairs Drawing up of simple
specifications
(b) A fuller knowledge of ship construction than in previous examinations.
General structure—transverse and longitudinal girders, keels; stem frame,
stem and rudder post, centre keelson, bilge and side keelsons; side stringers;
tank margin, intercostals; transverse framing; shell plating; rudder propeller
brackets, masts and derricks.
Classification of ships. Tonnage—measurement and registration.
Freeboard.
Treatment of accidents and damage—collision, springing leaks.
Possible strains incurred by action of waves, improper loading or
ballasting, etc.
Working of ship, division of loads.
(c) Stability diagrams and use of stability curves and information/
Effect of beam and freeboard on stability. Practical operations to ensure
ship stability at sea. Ship with a list. Management of ballast tanks. Effect
of free liquid surfaces and risks of flooding hold spaces, filling and emptying
tanks at sea. Suspended weights and shifting cargoes. Deck cargoes.
Homogeneous cargoes. Ballasting. Effect of admission of water into
interior of a ship. Flooded compartments. Stability and trim of a stranded
ship. Trim—moment t;o change trim.
56, Paper 4, (Written.) English. {2 hours.)
This paper will test the candidate's ability to write clear and grammatical
English, with good spelling and penmanship. It will be in no sense a test of
technical or legal knowledge.
57, Paper 5. (Written.) Ship's Business. (2 hours.)
(The legal information required will not go beyond the outline of Mercantile
Law which the shipmaster must know for practical purposes.)
(a) The official log and reports on exceptional Entries.
(5) A shipmaster's knowledge of the law relating to:—
(l) Engagement, discharge, and management of a ship's crew.
Ship's articles of agreement. Discipline and treatment of offences.
REGULATIONS
Wages and other remuneration Food and accommodation Entering
and clearing the ship. National Insurance of crew
(2) Tonnage, life-saving appliances, salvage and assistance and, in
general, the safety of ship, crew and passengers.
(3) Load Ime marks and entries and reports to be made respecting
them. Surveys required by law.
(4) Hygiene of ships, living spaces, holds, etc. Water Fresh and
preserved food. Infectious diseases The law relating to them and the
procedure on board in such case. Quarantine procedure Recognition
and simple treatment of common illness, e.g , fevers, etc. (See the Ship
Captain's Medical Guide .)
(5) The carnage of emigrants.
(c) simple knowledge of the law relating to cargo, including a knowledge
of shipowners’ liabilities in carriage of cargo.
(d) A general knowledge of shipping business and documents—charter
parties, bills of lading, etc. A knowledge of average—general and particular.
Flotsam and jetsam (XIX , XX.)
59 Paper 7. (Written.) Engineering Knowledge.
(Including Carriage of Refrigerated Cargoes.) (3 hours.)
(The requirements will not go beyond the knowledge that could be obtained
by a deck officer who takes an intelligent interest in the machinery
of the ship and supplements by a little reading what he has learnt
in this way.)
(a) The meaning of general engineering terms, e.g., horsepower, slip and
pitch of propeller, link, latent heat of steam, superheated steam, etc.
A general knowledge of a marine boiler and furnaces, and the procedure
for raising steam. The general action of a reciprocating steam engme.
Principle of the condenser. Distribution of steam from boiler to engines—
valves and pipelines. Admission to engme—slide valves, eccentrics, expansion
link. Starting gear. Simple descriptio|i (without detail) of various parts of
engines and boilers, e g , connecting rod, crank, piston and rings, packing
of piston rods, relief valves and cylinder drains, lme shafting, couplings, tail
shaft, stern tube and packing. Auxiliaries and their uses—circulating pump,
air pump, feed pump, bilge pump. Action of propeller. Thrust block.
Attachment of propeller to shaft.
Oil fired furnaces and use of. oil fuel. A simple knowledge of turbine
machinery and of Diesel engines. Warming up and turning engines. Stopping
and going astern—how done. A knowledge of what is required in the engine
room on the receipt of manoeu vrrng orders from the bridge. Fuel consumption
and economical speeds. Power and speed curves. Effect of alterations of
speed on fuel consumption and estimation of adequacy of fuel to complete
a given voyage.
(£>) An elementary knowledge of refrigeration on board ship. Types of
refrigeration on board ships. Types of refrigeration employed in specialcases.
Stowage and general handling of refrigerated cargoes.
. 60. Oral Portion.
— [a) Exceptional circumstances—loss of rudder; shifting a damaged
rudder. Construction of jury rudders. Making and launching of rafts.
Collision. Leaks. Damage of all kinds. Running repairs and precautions
in case of accidents. Grounding—methods of refloating. Beaching a vessel
Steps to be taken when disabled and in distress.
(5) Preservation of crew and passengers iu the event of wreck. Abandoning
a wrecked ship. Rockets and rocket apparatus. Communications with the
shore.
{c} Assisting a vessel in distress. Rescuing crew of a disabled ship.
3 - fa) Tewing and being towed.
REGULATIONS
(e) Bad weather manoeuvres Precautions at anchor and at sea Use
of oil
Anchoring and working anchors and cables in all' circumstances.
Approaching rivers and harbours and manoeuvring m them
(/) Drydocking General procedure and precautions to be observed
Distribution of weight. Drydocking with full cargo for inspection of
propellers or shaftmg Bilge beds. Leaving the vessel water borne.
Putting into port with damage to ship and/or cargo, both from business and
technical points of view Safeguarding of cargo.
(g) Prevention of fire at sea. Spontaneous combustion of fuel cargoes
Full knowledge of the use of fire extinguishing appliance and precautions to
be observed m cases of danger to lite Special reference to extinguishing of
oil fuel fires.
(h) Methods of fumigatmg holds and living spaces and safeguards in
applying them.
(i) General organisation of ship’s work and handling of crew.
2. —Regulations for Prevention of Collision at Sea, etc .—As par. 42,
Section 5 (Oral), Second Mate
3. — Signals .—As par 42, Section 6 (Oral), Second Mate.
4 —The examiner may ask the candidate questions arising out of the
written work, if he deems it necessary on account of weakness shown by the
candidate.
MATE (QOME TRADE).
80. Oral.
1. The content and application of the Regulations for Preventing
Collision at Sea. Distress and pilot signals; penalties for misuse The use
£f the rocket apparatus. An intelligent use of “Notices to Manners’'
(Candidates will not be required to commit these to memory.) (IX , X , XI)
2. Marking of ordinary lead line. The use and upkeep of mechanical
sounding machines and logs. Construction and use of engine-room
telegraphs. Anchor work; coming alongside; mooring and unmooring.
Management of a ship’s boat. (V,, VIII., XIII.)
3. Understanding of bulkhead sluices, bilges, bilge pumps, water ballast
tanks, sounding pipes and the ventilation of holds. Fire extinguishing
appliances. (VIII., XVII)
4. An elementary knowledge of cargo work, as given m the syllabus for
First Mate (Paper 5, Section d ). (XVI.)
5. To read and understand a barometer and a thermometer. To use a
sextant for taking vertical and horizontal angles and to find the index
error. (VIII.) . x
Signalling .—British Semaphore up to 8 words a minute. Morse flashing
up to 6 words a minute. International Code of Signals. (XIX.)
85. Oral.
MASTER (HOME TRADE).
1, International Regulations for Prevention of Collision at Sea and
everything contained in Section 1 (Mate Home Trade). (IX., X., XI.)
2 Handling a ship in bad weather and when it is disabled. Preservation
of crew and passengers in event of wreck. A fuller knowledge of mechanical
sounding machines and logs Effect of screws on steering of a ship. (XIII.}
* 3 Understanding of effect produced by filling and emptying ballast tanks
and loading and unloading cargo on the centre of gravity of the ship as a
whole * the danger of free liquid surfaces in tanks and holds. (X vT., XVIII.}
4. A shipmaster’s knowledge of the law relating to load line marks and
entries and reports to be made respecting them. (XV)
5, To read and understand a barometer, thermometer and hydro¬
meter. (VIp.)
Signalling. —As for Mate (Home Tradej.
REGULATIONS
APPENDIX H.
Sea Service required to qualify for examination for Certificates of Competency
The following is a condensed statement of the sea service required to
qualify in each of the various grades of Certificates of Competency. Where
service as an officer is required it is shown m tabular form. The letter F is
used as denoting foreign-going and H as denoting Home Trade* thus 1J F in
the first column of the table showing the officer's service for a First Mate's
Certificate means 1£ year’s service m foreign-going ships. Mate H in the last
column means Mate of a Home Trade ship, and so on.
A candidate for sailing ship endorsement must show that at least 12
months of his service has been spent m square-rigged sailing ships.
CERTIFICATES FOR FOREIGN-GOING SHIPS.
Second Mate (Foreign-going).
Minimum age, 20 years. Minimum sea service, 4 F or 6 H.
No officer’s service required.
First Mate (Foreign-going).
Minimum age, 21J years. Minimum sea service, F or 8£ H.
Officers services follows.
Years. •
Lowest capacity.
Lowest certificate
required.
li F
Third of 3 watch-keeping officers
2nd Mate F
or
2*H
Only Mate or First Mate
2nd Mate F
Note. —In certain circumstances service as Second Mate in the Home
Trade may be accepted.
Master or Extra Master (Foreign-going).
Minimum age, 23 years. Minimum sea service, 7 F or 10} H.
Officer's service as follows:—
Years.
Lowest capacity.
Lowest certificate
required.
,li F
2i H
2 F
2iF
S H
First Mate.
or
Only Mate or First Mate
or
Second of 3 watchkeeping officers
or
Second of 2 watch-keeping officers
or
Third of 3 watch-keeping officers
or
------
First Mate F
First Mate F
First Mate F
First Mate F
*
First Mate F
Second ,Mate F or
Master H for one
year, of such service
REGULATIONS
CERTIFICATES FOR HOME TRADE PASSENGER SHIPS.
The service required for these certificates may have been performed either
in Home Trade or m Foreign-going ships.
Mate (Home Trade).
Minimum age, 20 years Minimum sea service, 4 years.
No officer’s service required.
Master (Home Trade),
Minimum age, 23 years. Minimum sea service, 5 years.
Officer’s service as follows —
Years.
Lowest capacity.
Lowest certificate
required.
1 H
Only Mate.
Mate H or Second
or
Mate F
2i H
; Second Mate m chcuge of watch
** it
Apply to any navigation school tor information regarding temporary
war time modification of sea service qualifications
MERCHANT NAVY TRAINING BOARD.
PRACTICAL SEAMANSHIP.
FIRST YEAR
Saflorising.—Learn to box the compass in points.
Different rigs of sailing boats and sailing ships. Types of steamers. Pages
4 to 6.
Whipping a rope; bends, hitches and knots; seizing and rackmgs; eye-splice
and short splice; worm, parcel and serve. Pages 8 to 22, 611, 612.
Blocks, tackles, ropes and their uses. Spanish windlass. Pages 26 to 33.
The rigging of steamers. Page 49.
The names of the different kinds of lines and ropes in general use, the nature
and materials of which they are made, the forms of their make, the uses to
which they are put and the means to be adopted to ensure their long life.
Pages 8, 49 to 65, 611.
Cargowork*—Draught marks on stem and stem posts. Load line marks
Pages 372 to 385.
Length and size of strops, slings, belts and nets used in handling cargo.
Pages 386 to 391.
Preparation of holds for cargo. Cleaning of bilges and clearing suction
rose boxes. Closing and battening down hatches and gangway doors. Pages
398, 559, 604
Apparatus.—Handling and upkeep of patent logs and patent sounding
machines. Marks on hand lead and band log lines. Pages 124 to 140*
Statutory,—Leam to repeat the Articles of the Rule of the Road. Pages
183 to 205.
Signalling.—Signalling by Morse, semaphore. Flags of the International
Code of Signals* Chapter XXII, page 617*
SECOND YEAR. ,
Safforising.—Ship routine* Pages 1 to 5,177 to 179*
Long splice*in rope, eye-splice in wire. Safe working load of rope, wire
and chain. Pages 20 to 25.
Seaming and roping palms, sewing canvas, awnings and tarpaulins.* Different
grades of canvas and their uses. Pages 62, 63.
merchant navy training board syllabus
Handling and management of boats under oars and sails Pages 66 to 82
Anchors and cables Pages 115 to 122, 543.
Cargowork. —Care and overhauling of cargo gear and its duration of life
Dunnaging cargo and hold ventilation, necessity for dunnage and its proper
use. Shifting boards and feeders. Mats and other means of separating
parcels of cargo when such earned The need for and the preparation of
cargo plans Pages 386 to 420.
Hold ventilation Pages 476, 478, 506
Maintenance. —Paint and paint mixing, quantity of pamt required to
cover various parts of the ship. Precautions taken to prevent rust forming
on shell plating, on deck plating and m holds Use of cement and cement
wash Pages 480 to 482, 613.
Statutory.—A full knowledge of contents and application of the Regulations
for Preventing Collisions at Sea. Pages 183 to 235
Responsible Duties. —Duties with carpenter, boatswain and lamptrimmer.
Responsible (under an officer) for logs and lines, hand lead and lines and
sounding machines
Responsible (under an officer) for gear of one boat and its readiness at all
times for boat drill which must always be attended
On duty near an officer on all occasions entering and leaving port or
anchorage and when shifting ship m port.
Night watches to be kept on the bridge.
A portion of some of the day watches at the wheel in fine weather away from
land
Cleaning paintwork and bnghtwork. Rigging of stages, painting down
masts and funnels and overside.
THIRD YEAR.
Sailorising. —Sending topmasts, gaffs and signal yards up and down.
Bending, setting and taking in fore and aft sails. Fitting of rigging, turning
in dead eyes and hearts. Use and overhaul of rigging screws, setting up of
rigging, rattling down. Pages 49 to 65, 612.
Boat stations. Use of oil in bad weather. Lifeboat equipment, lifebuoys,
lifebelts and their tests. Pages 82 to 114.
Maintenance. —Use and upkeep of engine room and other telegraphs.
Pages 124 to 127.
Knowledge of use and maintenance of deck appliances and steering gear;
different types of steering gear. Pages 157 to 164. Relieving tackles.
Page 609.
Fire fighting appliances, their care and maintenance. Fire and boat drill.
Pages 172 to 178.
Precautions to be taken with bad weather approaching, hatches, ventilators
■ and lifelines. Precautions to be taken before nightfall. Page 607.
i The nature of pigments, oils and varnishes used in ship work, together with
explanations as to the reasons for using different types of paints, compositions
and varnishes for certain parts of the ship. Bituminous compounds, their
uses and reasons for same. Pages 480, 481, 613.
A portion of some of the day watches on the bridge in narrow waters.
Cargowork. —Tallying cargo. Mate’s receipts, their value and need for
accuracy. Protests, their meaning and value. Parcels of cargo liable to
.’damage other cargo, precautions to be taken. Dangerous cargoes, stowage
and precautions. Deck cargoes. Pages 386 to 420, 540. . >
Sfatutory.— Safety requirements under Factories Act as applied to ships.
Pages'38% 659. > r ***
Peri AM. ,
4 V ^ PRACTICAL SEAMANSHIP.
J FOURTH YEAR. / ,
of boats at sea and gettingvawaY tram ship’s ride*
weather.. .■ . Pages 83to 92. .• « <’
merchant navy training board syllabus
lI9^12i ai 331 0rS ’ and uses - Ranging of chain cables m drydock Pages
Pag« e i79 n 298 Wat ° h ’ dra *» in « anchor - Duties of officer of watch.
p r0 feeXg a toTe S a "p4£^m getting underwa > r - Duties P rior to
Ins^tioo^l,^ 01 *. entel “8. while in and before leaving drydock.
U “ der water parts in drydock Pages 339, 430, 615.
and ^?v^,J„iT The a f an gements of derrick and cargo working gear. Rigging
and working of heavy derricks Pages 45,46, 55 , 388 . 8
Refrigerated cargoes. Pages 410 to 416.
? f . compa 1 s t0 ascertain risk of colhsion. Pages 210 to 213
Uniform S-stem slgnaJs ’ P eaaJties for misuse Notices to Mariners.
236^254J 569 ™570 ^ R ° Cket and hne throwin g apparatus Pages ’
Slnp hygiene and fumigation. Pages 555, 556.
signalling.— Morse, semaphore. International Code Flags of all nations
Use of commercial code books Chapter XXII, page 617 g
SHIP CONSTRUCTION.
FIRST YEAR.
Stedpd wooden masts and derricks with their attachments and standing
and running rigging and gear. Pages 49 to 56. 8
Deck sheathing and waterways. Pages 433, 437 449
457 to 4 C 60, C 6oHo3. ****""*• and covers both wood and steel. Pages
Sounding pipes. Air pipes. Pages 475, 476.
SECOND YEAR. (In addition to previous year.)
Local stiffening at ends of vessel and under boilers, engines, winches
windlass, etc. Pages 426 to 431. 6 ' w ^ caes '
Tank top plating. Plating of shell, bulkheads and decks. Pillaring and
stanchion arrangements. Pages 438 to 457. s a
Rudders of various types. Pages 464 to 468.
Bilge and tank pumping arrangements. Pages 474 to 476 604
Carlin beams and partners. Page 602.
THIRD YEAR. (In addition to previous year,) *
Names of the principal parts of a ship, s g. keel (bar and plate). Floors
(solid and skeleton) and double bottom. Centre girder or keelson. Side and
bilge keelsons. Pages 432 to 442, 597 to 601.
Stem bar, stem post, body post, stem frame, stem tube. Pages 460 to 474.
FOURTH YEAR, (In addition to previous years.)
A ship as a girder. Stresses a ship has to resist, longitudinal, transverse
collapsing, local. Pages 426 to 432. ’
Longitudinal and transverse systems of framing. Beams anti beam kn^ s
Stringers and stringer plates and methods of attachment of the various Darts*
The construction of the cellular double bottom with its various members
Pages 433 to 442, 471, 478, 597 to 601. various memt»ers.
Names of the various types of rivets and reasons for these. Pages 444 to
446. 1 e
Parts of a ship particularly liable to corrosion and methods of dentine
with it in peaks, bunkers, doable bottom tanks, etc. Pages 480, 481, 6137^*
SPECIAL TYPES OF SHIPS FOE SPECIAL CARGOES.
The following section is inserted as it is necessary that an apprentice's
Jmo^ledge should not be confined to the type or types of vessels upbn which
he, happens to have Served. r
MERCHANT NAVY TRAINING BOARD SYLLABUS
Timber Carriers.—Deck loads and methods of securing Pages 408 to 410
Tankers.—General arrangement of ship and tanks and cargo arrangements,
pipes and valves; precautions against admixture of cargo Pages 416 to 420
Refrigerated and Insulated Ships.—General elementary principles of refrig¬
eration. Different temperatures for different cargoes, such as chilled meat,
frozen meat, dairy produce and various kinds of fruits. General elementary
principles and methods of insulation Pages 410 to 416, 607
Load Lines Generally.—Special load lines for tankers and timber laden ships
and reasons for variation. Pages 476 to 480.
MISCELLANEOUS KNOWLEDGE.
FIRST YEAR.
Knowledge of simple machines, e.g . tackles, meaning of mechanical advan¬
tage, strength of rope, wire and hemp. Pages 26 to 40.
Resolution of forces. Action of forces on a derrick. Pages 263 to 276.
Centre of gravity; simple examples Moments of the forces as applied to
levers, capstan and winches Pages 488 to 500.
Hydrometer and its use. Specific gravity. Buoyancy. Pressure m
liquids; variation with depth and application to sounding machines. Pages
359 to 372.
Flotation and its application at sea. Use of load lines. Pages 372 to 385.
SECOND YEAR.
Construction of a thermometer. Meaning of temperature. Centigrade*
Absolute, Fahrenheit and Reaumur scales, conversion from one to the other*
maximum and minimum thermometers. Absolute zero. Pages 147 to 150.
The marine barometer, aneroid barometer, barograph. Construction .of a
barometer. Measurement of air pressure, units, e.g bar, millebar. Pages 14J
to 152.
Air pressure. Variation of air pressure with height and latitude.
The atmosphere and its humidity. Vapour pressure and dew point; the
wet and dry bulb hygrometer and its principles and uses. Page 151.
Boyle's and Charles's Law.
Reflection of light by plane mirrors. Effect of reflection by rotation of
mirror as in the sextant. Sextant errors and their correction Guide, Vol I.,
pages 298 to 311.
Refraction of light by azimuth mirror. Guide, page 179. Atmospheric
refraction. Guide, page 315.
Formation* of images by lenses Magnification of a telescope.
THIRD YEAR.
Definition of “metacentre" and “metacentric heights." Stiff and tender
ships. Pages 403, 501 to 506
__ Plotting T P.I. and displacement curves. Calculation of displacement
using a block coefficient. Tons per inch calculations. Deadweight scales.
Pages 509 to 515.
Effect of filling and emptying ballast tanks on centre of gravity as a whole.
Esti ma ting weights of simple parts of ship's structure. Displacement and
sinkage of box forms. Centre of buoyancy and centre of flotation. Pages 515
to 530.
FOURTH YEAR.
1 Recapitulation for second mate's examination.
ENGINEERING KNOWLEDGE.
The purpose of this subject is not to provide an apprentice with a detailed
knowledge of engineering, hut to enable him to appreciate the functions of the
various engineering appliances on board ship in a simple manner,
^4 The textbook, Engineering for Nautical Students, by W. A, Fisher,
A.M J.Mech.EA.R.T.C., has been written to meet the requirements of this
Syllabus. Published by Brown, Son & Ferguson, Ltd., Glasgow, price 7/S v
merchant navy training board syllabus
FIRST YEAR
Use of instruments and scales
The sketching of such objects as nuts, bolts, rivets and simple engine parts,
c g. a winch piston, a stop valve, a connection rod for a small engine.
Drawing m plan and elevation
How drawings are dimensioned.
Practice in this work by making a dimensioned sketch from a given object.
Dimple ideas of the working of a reciprocating engine, e g winch; names of
essential parts and method of lubrication.
How a steam windlass works. Differences between gear wheels and worm
gear ®
Simple ideas on the general construction of marine boilers
How to operate a steam valve. How pipe lines are drained Danger of
frost on pipe lines and winch cylinders
How steam is produced m a steam boiler. How it works the engine.
SECOND YEAR.
Steering gears, their types and the various means of operation.
The various pumps on board ship, e.g. feed, ballast and bilge, and how they
are worked.
The pipes and valves for pumping out bilges, ballast and oil tanks
The shafting from engine to propeller and the means by which the thrust of
the propeller is transmitted to the hull of the ship.
How coal and oil are burned m the furnace of a marine boiler.
Danger of fire and the means of preventing, detecting and extinguishing it
How a refrigerating machine works; the importance of insulation; how the
chambers axe cooled.
Simple idea of how a steam turbine works.
Simple idea of how a Diesel engine works.
THIRD YEAR.
How electrical pressure, current and resistance axe measured. Ohm’s law.
Some idea of the size of the units by reference to ships’ lighting and power
supply. Dangerous voltages (dry and wet body).
'What a current of electricity can do: simple ideas of magnetic, heating and
chemical effects.
Heating effect of a current—how it increases with an increase in the strength
of the current. Melting of substances: effect of temperature upon conducting
and insulating properties of substances. How insulated cables tend to insulate
heat and so raise temperature. Fuses.
Primary and secondary batteries. Care and use of accumulators.
Electrical corrosion.
Why a ship’s supply must have a constant pressure Building up a
simple lighting circuit. What candle power is—how C.P. depends upon
electrical power—how it vanes in different types of lamps—how lamps are
rated. Lamps in senes and in parallel.
How an electro-magnet works, the electric bell and buzzer, telephone,
microphone and moving iron ammeter.
How a D.C electric motor works. Application in the construction of
moving coil ammeter.
Simple ideas of the principle and construction of a dynamo. The spring
cut-out as safety device Direct and alternating current. The transformer.
Different types of motors used in ships: the functions of the starter. ,
Electrical heating and lighting appliances found aboard ship. The
measurement of energy in watts. Board of Trade units: the relation of watts to
horse-power. „
Simple ideas on the main parts of a ship’s wireless apparatus.
MARINERS’ COMPASS
TABLE
OF
THE
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*
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45"
e *..
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18'
45'
i-
... 5
87
80
2 i...
..28
7
80
4i...
...50
37
30
«*..
...73
7
30
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26
15
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56
15
4|...
...58
26
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16
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0
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...56
15
0
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45
0
li-
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45
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83
45
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3
45
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45
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84
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80
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0
NICHOLLS’S
SEAMANSHIP AND NAUTICAL KNOWLEDGE
Nicholas Seamanship and Nautical Knowledge
CHAPTER L
S EAMANSHIP is the work of the seaman on board ship. A vessel
is organised into three departments, deck, engine and cabin, the
members of each department being all referred to as seamen in the
Merchant Shipping Act, but our work refers to the duties of the deck
executive. Seamanship and navigation are different branches of
nautical work; a seaman, for example, need not be a navigator but a
navigator must needs be a seaman.
Formerly, in the days of sail, seamanship included the maintenance
of standing and running gear and the manipulation of all the vessel’s
paraphernalia of yards, sails and cordage in manoeuvring the sailing
ship by applying, m a rough and ready but very practical manner, the
principles of mechanics to the propulsion of the wind-driven ship and
the operation of manual machines.
The sailing vessel as a commercial proposition so far as Great
Britain is concerned has passed away and much of the knowledge
peculiar to her equipment is now obsolete. But seamanship of a
somewhat different asd perhaps of a more comprehensive character is
required from officers of the modem steamship. The sea has not
altered nor have the fundamental nautical principles, but the ship
herself has undergone radical change, the methods of propulsion
equipment* communication, maintenance and control have altered so
much that a different kind of knowledge and handcraft is now
required from the seaman who aspires to executive position.
The development of sea transport has called up much legislation in
the interests of life and property at sea, and a knowledge of statutory
regulations relating to what may and may not be done in many diverse
ways regarding structural detail, the equipping and handling of the
ship* the loading of cargoes, rule of the road and other compulsory
safeguards, form a large part of a seaman’s duty and call*for under-*
standing .and a sense <rf responsibility.
2
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
It is convenient sometimes when indicating roughly the direction
of an object external to the ship to divide the horizon into sectors
relative to her fore-and-aft line. An object may be reported as being
ahead or astern, on starboard bow or port bow, on starboard beam or
port beam, starboard quarter or port quarter.
AHEAD
Thus the white masthead lights show from right ahead to two
points abaft the beam on each side; the green side-light shows from
right ahead to two points abaft the starboard beam; the red side-lighc
from right ahead to two points abaft the port beam; the white stein
light from right aft to two points abaft the beam on each quarter.
The Lookoutman is stationed on the forecastle-head or in a crows-nest
on the foremast and, like the man at the wheel, he usually does a two
hours’ “trick. 55 When the lookoutman sights a light on the starboard
bow he usually intimates the fact by one stroke on the bell, two strokes
for a light on the port bow, and three strokes when it is sighted right
ahead. He may supplement this signal by calling out the fact to the
officer, on the bridge.
The Day at Sea is divided into watches of four hours each, viz., from
midnight to 4 a.m., 4 to 8, 8 to 12,12 to 4 p.m,, then two “dog watches”
4 to 6 and $ to 8 to break the sequence and then 8 p.m. to midnight.
The dog patches are only necessary in the watch and watch system, four
hours on deck and four hours below,
y Bells are struck every, half-hour in each watch, an additional stroke
for every successive half-hour; thus four bells in the, middle watch at.
% ama., six bells at 3 a.m., seven bells at 3*30 and e%ht beJUs at 4 o’clocjb-
The watches are changed at eight bells and the same sequence of
half-hourly bells repeated. The watch below is called fifteen min utes
before eight bells, and it is a habit of disciplinary nautical etiquette to
relieve the watch on deck promptly on the stroke of eight bells. Form*-
erly, the watch and watch system was universal and it is still the usual
routine for deck hands, except on ships where quartermasters are spec¬
ially engaged to steer the ship, in which case the deck hands are usually
on whole day work, each man taking a turn on the lookout at night.
The officers, however, are organised in three watches, the chief officer
taking the 4 to 8 watch morning and evening, the third officer the 8 to
12 watches, and the second officer the middle and afternoon watches
from midnight to 4 a.m. and noon to 4 p.m.
Helm Orders .—The rudder in very small ships is turned by a helm
or tiller as in the life-boats. The helm has disappeared from ocean-going
ships but the name still survives and only the rudder remains the same.
When it is desired to turn the ship’s head to starboard, the rudder
is angled to starboard by turning the steering wheel so that its upper
half also turns to starboard; conversely, when the ship’s head is turned
io port, the rudder is angled to port by turning thg wheel sd that its
upper half also turns to port, all of which sounds quite intelligible and
logical The word helm for some unexplained reason is still retained and
the Board of Trade has intimated that “from 30 th June, 1931, helm or
steering orders to the steersman shall be given in the direct sense , e.g. when
the ship is going ahead an order containing the word 8 starboard ’ or Wight
or any equivalent of 8 starboard ’ or Wight shall only be used when it is
intended , on ships as at present generally constructed and arranged , that
the wheel , the rudder-blade and the head of the ship, shall all move to the
right”
This recommendation also forms the text of Article 41 of the
International Convention (1929).
We have purposely avoided using the word helm in this book and
have referred to the action of the-rudder direct which, after all, is the
apparatus that causes the ship to turn.
Conning the Ship.—'When the command is given “port 10°” the
man at the wheel replies in a responsible manner “port 10°, sir,” and
then turns the wheel until the indicator on the steering wheel pillar
comes to “port 10°,” the rudder is then at an angle of 10° with the line
of the keel and the ship’s head will turn in response to the action of the
rudder/ In senate ship the order “port 10°” would mean steer 10° to
poxt of your course. The order may be u hard-a-port” or “hard-a-
Barqucnlfn*
Barqu*
TYPES OP STEAMSHIPS
*
starboard,” whereupon the wheel is turned in the required direction
until it can go no further Incidentally, it may be remarked that the
angle of maximum turning efficiency of the rudder is about 35 degrees.
When the ship’s head is swinging the officer may order “ease the helm”
to which the quartermaster at once replies “Ease the helm, sir” and
brings the wheel back a few turns. But should the order be a peremptory
“Steady” the quartermaster replies “Steady, sir,” and notes the direction
of the ship’s head at the time by the compass, or by an object in sight
ahead of the ship and steers straight for it. All steering orders are
repeated by the man at the wheel in a clear, responsible manner.
When the wheel is relieved at sea the man going off steadies the ship
on her course and announces the course distinctly to his relief man, who
repeats it when taking over. The man going off duty reports the course
to the officer of the watch, who repeats it and then makes sure the new
man at the wheel is steering the proper course.
Sailing Ship Rigs.—It is still essential to be able to recognise sailing
vessels by their rig if only for reporting intelligently about them when
sighted at sea. On page 4 the silhouettes give an indication of their
general outlines.
Types of Steam Vessels.—Steam vessels also have their characteristic
features, probably more varied than sailing ships ever were, and seamen
can often identify ships belonging to particular companies by little
peculiarities in their general outlines, the rake and positions of their
funnels and masts, the arrangement of deck erections, etc., long before
they are near enough to distinguish the colours and markings of funnels
"and hull, assisted, no doubt, by a knowledge of their trading routes.
We give here a few silhouettes of distinctive types of ships.
TYPES OF STEAMSHIPS.
A Flush Deck Ship
A Tanker
CHAPTER H
KNOTS, BENDS, SPLICES
The Construction of Hopes
Rope, the term being used in its widest construction, is made from
almost every pliable material, but is generally composed of hemp,
manila, coir, cotton, steel, iron, or copper wire. Bee page $11.
For the present we will confine ourselves to those having their
origin m the vegetable kingdom, and more especially to those made
from hemp and manila.
These are divided into three classes:—
(1) A Hawser-laid Rope, which is composed of three strands laid up
generally right-handed (that is, the direction taken by the /
strands in forming the rope runs always from left to right) (Fig. 1).'
(2) A Shroud-laid Rope, also laid up right-handed, but consisting of four
strands with a heart in the centre (Fig. 2).
(3) A Cable-laid Rope, which is composed of three right-handed hawser-
laid ropes laid up together left-handed, so that it may be
said to consist of nine strands (Fig. 3). See also page 612.
Fig. 1. . Fig. 2. F>g- 3.
A ^
KNOTS AND BENDS U
(1) Whippings. The end of a rope must always be secured in some
way, or it is evident from its construction that it will, on the slightest
usage, become frayed out The commonest method is by working on an
ordmary whipping, which is done as follows:—First lay the end of a
length of twine along the end of the rope, and then commencing at the
part furthest from the rope’s end take a half dozen or more turns around
both the rope and twine end (Fig. 4). Then lay the twme in the form of
a loop along the rope and over the turns already taken, as in Fig. 5. To
finish off take that portion of the loop designated a } and continue
taking turns tightly round the rope and part b of the twine until the
loop is nearly all used up; pull through the remainder snugly by part c,
and cut off short when no end of twme will be visible as in Fig 6.
Fi S* 4* Fig. 5. Fig. 6. Fig. 7.
Whippings.
(2) A Palm and Needle Whipping (Fig. 7) is a more permanent way of
securing a rope’s end from fraying than the common whipping put on
by hand. First, place the needle under one of the strands and draw
nearly the whole length of twine through. Take a considerable number
of turns round the rope with the twine, drawing each well taut in turn,
and finish up by following round with the needle between each strand,
forming a series of trappings, and cut off the end of the twine short*
(3) A West Country Whipping is formed by middling the twine
around the part of the rope to be marked and half knotting it at every
half turn, so that each half knot will be on opposite sides. When a
sufficient number of turns are passed, finish it off with a reef knot.
Considering that we now have at our disposal a small sized rope
with the end whipped, we will at once proceed to the formation of th*
most elementary knots and hitches, namely, those formed by a single
mpe*s end*
I
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Fig. 8.
A Bight.
Fig. 9.
Overhand Knot.
Fig 10.
Figure-Of-Eight.
KNOTS AND BENDS
11
A Common Loop, by which, most of the following knots)^^ are^
commenced. Note exactly how the loop lies, and let ns letter rfe*p!5!a«
clearly for future reference. The part of rope extending from 1 to 2 is
known as the standing part which we will call a, the portion included
between 2 and 3 following round the loop by y and z is termed the bight
which we will call 6, and from 3 to 4 is known as the end c.
Then starting in each case from the position shown in Fig. 8 we
make the following knots, etc.:—
An Overhand Knot.—Place c up through bight 6, and draw taut.
A Figure-of-Eight Knot.—Back c round behind a , bring over part z
and dip down through bight b and haul taut.
A Bowline.—Reverting to our original loop first taking part z in
the right hand with y in the left, throw a loop over c, the end.
Secondly, lead c round behind part a and pass it down through the
last made loop, as indicated by the dotted line, and haul taut as in
Figure 12.
Fig. 13. Fig. 14- Fig. 15.
' Half Hitches.
1 The formation of a half hitch (Fig. 13)* and two half hitches (Fig. 14)
is sufficiently indicated by those diagrams.
The commonest method of making a rope’s end fast to a bollard, etc.,
12
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
is by taking a round turn and two half hitches, and stopping the end
back for further security (Fig. 15).
Fig. 16. Fig. 17. Fig. 18.
Clove Hitch.
A Clove Hitch is really a jam mi ng form of two half hitches, and i A
principally used when a small rope has to be secured to a larger one and
the end still kept free to pass along for further purposes, as in securing
ratlines to the shrouds. Its formation is shown in three successive
stages (Figures 16, 17, 18).
A> Bolling Hitch is commenced and finished like a clove hitch, but
as will be seen from the three diagrams (Figs. 19, 20,21), illustrating its
construction, there is an intermediate round turn between the first
BENDS AND HITCHES
13
and last hitches. It is principally used for securing the tail of a handy
billy or snatch block to a larger rope, or when hanging off a rope with a
stopper.
c
Fig. 21, Rolling Hitch. Fig. 22.
Note that the ' round turn in Fig. 20 is taken round both the standing
part a and the larger rope. The great value of this hitch is its non¬
liability to slip in the' direction B (Fig. 21). If, however, owing to an
extremely severe strain or other causes the hitch is inclined to slip,
the end c should be backed round part d of the first rope, that is, twisted
around it in long lays in the opposite direction’ to that in which the
hitch was formed, and the end secured by a stop (Fig. 22.)
Jig. 2$.—Timber Hitch .
14
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
A Timber Hitch is a useful way of securing a rope quickly to a plank,
but when there is to be a long and continuous strain, or when it is
required to keep the end of a piece of timber pointed steadily in one
direction, it should be supplemented with a half-hitch (Figs. 23, 24.)
Fig. 24.
The timber hitch itself consists simply of a half hitch taken with a
rather long end, which is used up by twisting it back around its own
part of the hitch. The hitch is purposely left very loose so that its
formation may be the more easily seen in the illustration (Fig. 23).
Fig 25. Fig. 26.
Fisherman’s Bend.
A Fisherman's Bend is formed by taking two round turns around
the object to which the rope is to be secured, and then backing the end
round in the form of a half hitch under both the standing part and
second round turn.' The end may be further secured by taking a half
bitch around its own part ox by stopping it to it (Figs. 25, 26), the
dotted line showing the next direction the end c must take.
A Blackwall Hitch is a quick way of temporarily securing a rope
to a hook. As will be seen from the illustration (Fig, 27) it consists of a
half Mtch, the standing part ct as soon a§ it receives the' strain jamming
tie end part c. It holds much more firmly than would be; imagined at
first ysight By taking another round turn at b, before passing ,th£
c under a, it will hold more securely. . 1 < ^
*ig 27.
Fig. 28.
Blackwall Hitch.
Fig. 29.
A Midshipman’s Hitch is sometimes used instead of a Blackwall
hitch, and will hold better if the rope is at all greasy. It is made by
first forming a Blackwall hitch and then taking the underneath part
and placing it over the bill of the hook (Fig 28).
A Double Blackwall Hitch is made by taking the bight of the rope
and placing it across the neck of the strop of the block, crossing it
behind, then placing the under part over the hook and crossing tk*
upper part on top of it. It holds better than either of the two preceding
hitches (Fig 29)
Fig 3G, ^ Bowline. Fig. 31.
A Bowline on the Bight—Using both parts of the rope together,
16 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
commence as in making an ordinary bowline (Fig. 30). To finish oi
open out bight c, and taking it in the direction indicated by the dott€
line, pass the whole knot through it and haul taut, when it w]
appear as in Fig. 31.
Fig. 32.
A Marline-spike Hitch is used for getting a purchase with a marline
spike, capstan bar, etc., when putting on a seizing or lashing. It wi
be* seen to consist of the standing part picked through a loop laid ove
it, so that the spike lies under the standing part and over the sides c
the loop.
A Sheepshank is used for shortening a rope. Gather up the amour
desired in the form of Fig. 33. Then with parts a and b form a half hitc
round the two parts of the bight as in Fig. 34. To render it still* mor
h
BENDS AND HITCHES
17
dependable the bight a and b may be seized or toggled to the standing
part as in Figs. 35 and 36.
Fig. 37. Catspaw. Fig 38.
A Catspaw is formed in a .rope to make a temporary loop for hooking
on the block of a tackle. First throw back a bight as in Fig 37.
Then taking hold of a and b in either hand twist them up as in Fig
38 1 bring together the two eyes o, and b and hook in the tackle.
KNOTS, BENDS, AND HITCHES FOR UNITING ROPES.
A Reef Knot. The simplest of all knots, and is always used when a
common tie is required. Its formation may be easily traced in Figs.
39, 40, 41. Having constructed the knot as far as Fig. 39, be sure
part a is kept in front of part b as here shown, and the end c led in
according to the direction of the dotted line.
A Common Bend or Sheet Bend.—In making a bend the ends of the
two ropes are not used simultaneously as in forming a reef knot, but an
18
NICHOLAS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
eye or loop is first formed in the end of one of the ropes as in Fig. 42 and
the other rope’s end is then rove through it in various ways according
to the bend desired.
Sheet Bend.
To form a Sheet Bend, pass the second rope’s end underneath the
eye at point a and bring up through the loop, then form with it a half
hitch round c and b (Fig. 43).
It will hold still better and is less likely to jamb if the end c is passed
round again as in Fig. 44.
Carrick Bend.—For bending two hauling lines together use a Carrick
Bend. First form with hawser No. 1 a loop as in Fig. 45.
Fig. 45. Garrick Bend. Fig. 4$.
NICHOLLS’s SEAMANSHIP AND NAUTICAL KNOWLEDGE
A Spanish Windlass—To rig a Spanish Windlass (Fig 50) take a good
strand well greased m the centre. Place the strand over the two parts of
he rope that are to be rove together, and bringing the ends of the strand
up again place a bolt close to the strand Take the ends of the strand
an ay them up with their own parts so as to form two eyes. Take a
round turn with this round the bolt, put a marline-spike through each
eye and heave around.
SPLICES.
An Eye Splice is formed by unlaying the end of a rope for a short
distance, and then, after closing up the end, to form an eye of the desired
size Lay the three strands upon the standing part, now tuck the middle
strand through the strand of the standing part of the rope next to it
against the lay of the rope (Fig. 51), then pass the strand'on the left over
e stmnd under which No. 1 strand is tucked, and tuck it under the
T i ^ an< * rema iaing strand through the third
strand on the other side of the rope as in Figs. 53 and 54.
Now tuck each strand again alternately over a strand and under a
strand of the rope, and then taper ofi by halving the strands before
tucking the third time, and again halve them before the fourth tuck
If the strands are tucked with the lay of the rope it is termed a
Sailmaker s Splice.
A Short Splice is used to join two ropes when it is not required to
pass through a block. Unlay the two ropes the required distance, and
SPLICES
21
clutch them together as in Fig. 55, that is, so that the strands of one
rope go alternately between the strands of the other
Then tuck the strands of rope a into the rope b m a similar manner to
that described in an eye splice and similarly tuck the strands of b into
Fxg. 57.
A Long Splice is one of the most useful of splices, as it permits the
tope to run through a block just the same as an unspliced rope.
Unlay the ends of two ropes to a distance about four times the length
used in a short splice, and then clutch them together as if about to
commence a short splice. Now unlay one strand for a considerable
distance and fill up the gap thus caused by twisting in the strand opposite
to it of the other rope. Then do the same with two more strands. Let
the rema ning two strands stay as they were first placed. The ropes
will now appear as in Fig. 58.
To finish off, tuck the ends as in a short splice, but with the lay of
the rope, that is, so that the tuck will continually take place around the
same strand, and taper off gradually by reducing the yams in the strand.
To Make a Grommet, cut a strand about three and a half times the
length of the grommet required. Unlay the rope carefully and keep
the turns of the strand in. Close up the strand in the form of a ring
(Fig. 59), and then pass the ends round and round in their original lay
22 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
until all tie intervals are filled up (Fig. 60), and then finish off the two
ends as in a long splice (Fig. 61).
F ‘g 59. Fig 60. Fig 61.
A Grommet.
WIRE SPLICING.
In splicing wire, great care should be taken to prevent kinks getting
in the rope or strands.
With steel wire, always before working it, put a stop on at the
place to which you intend to unlay, and also put a good whipping of
twine at the end of each strand.
Steel wire is six-stranded right-handed, and has a heart of hemp.
Flexible wire has a heart of hemp in each strand.
Crucible wire is made in the same manner, except that the strands
are wire throughout.
Crucible wire is used for standing rigging and flexible wire for
purchases, etc.
In splicing wire all tucks are made with the lay of the rope.
In making an eye splice the rope is handled better if hung up in a
convenient position so that when standing up the eye will be at about
the level of the chest of the person working.
A long tapering steel marline-spike is required, and after placing
it under a strand do not withdraw it until the tuck is made and all the
slack of the strand drawn through. ?
There are several methods in vogue for tucking the strand, but the
following is as good as any:—Tuck the first strand under two strands and
all the rest under one strand respectively. Tuck whole again, and
this time each strand under one strand, then halve the strands and
tuck again.
To make a neat splice do not Haul the part of the rope that has not
been unlaid too close to the neck of the splice, and in tucking the strands
never take a short nip but take long lays.
In unlaying for a long splice, always unlay two strands simultan-
WIRE SPLICING
23
eously, to keep the rope in its original lay. For a fair-sized rope unlay
about 9 ft. of each end.
Proceed as in rope splicing, and after the three pairs of strands are
in their places, single them, and continue to unlay and lay-in until the
six meeting places of the strands are equidistant.
To finish off the ends properly can only be learnt by observation and
actual practice. By using two marline-spikes, the hempen heart is
removed and the ends of the wire strands forced into the place it occupied
maldng a very neat job when finished
Wire splices should be parcelled with oily canvas and served with
Hambro 5 line
Splicing Thimbles—Under and Over Style.—Ordinary type of wire
rope. Serve the rope with wire or tarred yarn to suit the circumference
of the thimble, bend round thimble and tie securely in place with
temporary lashing till splice is finished (as in Fig. 62). Open out the
strands taking care to keep the loose end of the rope to the left hand (see
Fig. 63). Now insert marline-spike, lifting two strands as shown in Fig.
64, and tuck away towards the right hand (that is inserting the strand at
the point, and over the spike) strand No. 1, pulhng the strand well home.
Next insert marline-spike thiQUgh next strand to the left, only lifting
one strand, the point of the spike coming out at the same place as
before. Tuck away strand No. 2 as before.
The next tuck is the locking tuck. Insert marline-spike in next
strand, and, missing No. 3, tuck away strand No. 4 from the point of
24 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
the spike towards the right hand. Now, without taking out the spike,
buck away strand No. 3 behind the spike towards the left hand (as
shown in Fig 65). Now insert spike in next strand, and tuck away
strand No 5 behind and over the spike. No. 6 likewise. Pull all the
loose strands well down.
Fig. 66. Fig. 67.
This completes the first series of tucks, and the splice will, if made
properly, be as Fig. 66 now, starting with strand No. 1 and taking each
strand in rotation, t,uck away under one strand and over the next
atf&pd till all the strands have been tucked four times. If it js intended
WIRE SPLICING
25
to taper the splice, the strands may at this pomt be split, and half of the
wires being tucked away as before, the other half cut close to the splice.
Fig 67 shows the finished splice ready for serving over.
It will be noticed that this style of splice possesses a plaited appear¬
ance, and the more strain applied to the rope the tighter the splice
will grip, and there is no fear of the splice drawing owing to rotation
of the rope.
Fig. 68 —Wire Rope Grip.
Fig. 68 illustrates Messrs Davey & Co.’s wire rope grip which offers
a quick and effective substitute for splicing and fastening wire ropes
by unskilled labour.
Fig 69 —Sections of Wire Ropes.
Different methods of laying up the wires in each strand and of
twisting the strands together are shown in Fag. 69. The black shading
represents hearts of hemp rope.
HOW TO MEASURE ROPE.
26
NICBOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
BLOCKS.
A built block consists of a shell, strop, sheave, pm, shackle or hook
The score of a block is the groove round the outside of the shell
(Fig. 71), to take the strop, rope, or wire, when one is to be fitted. The
cheeks are kept apart by two pieces of wood, one at the head and one at
the tail of the shell to form the “swallow,” the name given to the space
the rope is rove through.
Fig. 71. Fig 72. Fig 73.
A Built Block. A Clump Block is cut Slieave Plain Bush
out of the solid wood.
The ahftlla of blocks are usually made of elm or oak as both kinds
of wood are good for resisting weather but they must be kept varnished
or painted.
Fig. 74.—Sheave, Roller Bush. Fig. 75.—Metal Sheave.
BLOCKS
27
The strop may be of rope or wire fitted into the score round the shell
and spliced as shown m the illustrations of tackles. The length of a
rope strop is about one and one-third the round of the block.
Sheaves are either of lignum vitae or metal Lignum vitae is an
exceedingly hard wood dark in colour and has self-lubricating properties
The bush of the sheave may be plain, that is just a hole drilled m gun-
metal (Fig. 73), or a roller bush (Fig 74), which runs with less friction.
Metal sheaves (Fig. 75) are used for heavy work. The size of a block
is the length of its shell; the size of a sheave is its diameter.
An External bound block (Fig 76) is one stropped with a heavy iron
band, an eye being welded on it for a hook or shackle.
An Internal bound block is one having an iron strop inside the shell,
one lug of which is sometimes extended outside the shell in the form
of an eye to take the standing part of the purchase The strop can be
withdrawn from the shell for cleaning and painting; pins of blocks are
scraped and rubbed with blacklead, so also are the sheaves and bush.
Fig. 76 . Fig. 77
External Sound Internal Bound
Block Block.
Fig. 78.
Iron Snatch
Block.
Fig. 79.
Wood Snatch
Block.
A Snatch block is a loose block having a hinged clamp at the side
(Figs. 78 and 79), so that the bight of the rope may be slipped over the
3 heave and the clamp closed again. They are handy as portable lead
blocks. Malleable iron pulley blocks (Fig. 80), are now universally used
for cargo work, and Fig. 81 illustrates another of Messrs. Davey & Co.’s
cargo blocks fitted with self-lubricating sheaves specially designed
for heavy work, the gunmetal centre, or bush, of the sheave having
28
NICHOLLS’S SEAMANSHIP AND NAUTICAL'KNOWLEDGE
cavities filled with solidified grease which is only liberated when the
sheave is working. See grooves in Fig. 75.
The simple machines are the pulley block, the wheel and axle, the
lever, the wedge and the screw. All other mechanical appliances are '
practically a combination of one or more of those simple machines
modified in form and application to meet particular requirements.
Fig. 80.—Metal Block. Fig. 81—Cargo Block.
In a simple fixed frictionless pulley (Fig 82), if W represents a weight
of 1 lb. due to the downward force of gravity, and P represents a spring
balance held in the hand, the balance will register 1 lb., thus demon¬
strating that a power or force of 1 lb. has to be exerted to equalise the
weight of 1 lb. If the weight of 1 lb. be overcome by exerting more power
at P eo that W moves slowly upwards, the balance will fully register
1 lb. whilst W moves up the same distance as P moves down. ' The
downward force at 0 wi/l be 2 lbs. No power is gained by this system
and a single pulley is only adopted in practice for convenience generally
as a leading block.
% Arrange the single pulley so that A is movable as in Fig. 83. Secure
BLOCKS
one end of the cord at C and attach the spring balance to the other end
at P . Hang a 2 lbs. weight at IF. The suspended weight of 2 lbs. is
supported half by the cord at O and half by the hand at P as indicated by
the balance registering 1 lb. The effort exerted by the hand at P is just
Fig 84. Pulley Purchases. Fig. 85.
one half of the weight to be supported. The mechanical advantage is
said to be 2 because a power of 1 lb. balance^ a weight of 2 lbs. It will
be noted that there are two parts of the cord at the moving pulley and
this number gives the mechanical advantage gained by this machine.
If the weight be now overcome by exerting more power at P so
30 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
that W moves slowly upwards, the balance will still register 1 lb.,
neglecting the effect of friction, and the hand will move upwards 2 feet
to raise the weight W 1 foot, because the work or power put into the
machine at P is equal to the work accomplished by the machine against
the resistance of the weight W. This may be expressed in foot-pound
units,Px2ft. = IFxl ft or 11b x2ft =2lbs. X lft.=2ft.-pds.of work,
The number of pulleys may be increased. Fig. 84 shows two movable
pulleys with a 4-lb. weight at W suspended from the lower pulley.
The cord AB supports the 4-lb. weight, 2 lbs. at A and 2 lbs. at B
attached to the upper pulley. A second cord passed round the upper
pulley supports the 2-lb. weight at B , viz., 1 lb. at C and 1 lb. at the
hand P holding the spring balance which will register 1 lb., neglecting
the weight of the pulleys, thus a power of 1 lb. supports a weight of
4 lbs.; the mechanical advantage of the machine is 4 because by its
performance a force of 1 lb equalises a load of 4 lbs.
If the load of 4 lbs. be now overcome by exerting more power at P
so that W moves slowly upwards, the hand at P will move 4 feet to
raise the load W 1 foot, thus
Px4ft.=IFxl ft. or, 1 lb. X4ft.=4 lbs. Xl ft.=4 foot-pounds of work,
again demonstrating that the work put into the machine at P is equal
to the work done by the machine against the resistance at W.
The arrangement as shown in Fig. 84 is not suitable in practice so
the sheaves are fitted into blocks as in Fig. 85. The principle is the
same, however, and the number of parts of cord at the moving block
gives the theoretical advantage or power gained by using the purchase;
that is to say, the ratio between the power and the weight which, in
this example, is one-quarter without friction.
There are four parts of rope holding the weight and it is evident that
the pull on each part will be one-fourth part of the total weight. The
load on the hook at G is equal to the weight+tackle+power exerted
on the hauling part of the rope. The weight of the load and tackle is
constant, but the power will depend upon whether IF is at rest or
being raised or lowered. When at rest P=1 lb, but when in motion
the value of P will be increased and diminished according to the
speed of raising and lowering. Needless to say, power is gained at the
expense of speed. The more sheaves in the purchase the more rope
must be hauled thrdugh the blocks to raise the weight a given distance,
and speed is thus sacrificed to gain power. It is usual in shipwork to
allow one-tenth of the weight for every sheave as an additional load
due to friction.
PURCHASES
31
PURCHASES:
The Mechanical Advantage gained by using a purchase is found by
counting the number of parts of rope at the moving block. This,
however, is merely the theoretical advantage as friction and the weight
of the block and rope are neglected.
Fig. 86.
Fig. 87. Fig. 88.
Fig 89 Fig. 90.
Single Whip.—A rope rove through a single block fixed in any
position. No power is gained (Fig. 86).
Double Whip.—A rope rove through two single blocks—upper
block a tail block, lower one a movable hook block. Power gained_
double—that is weight of one unit on the hauling part will balance a
weight of two units on the hook block (Fig. 87).
Gun Tackle.—Two single blocks. Power gained two or three
according to which is the movable block. If the upper block in the
figure is the moving one the purchase is said to be rove to advantage
and the power gained is 3; but if the lower block is the moving one the
purchase is rove to disadvantage and the power gained is 2 (Fig. 88).
Handy Billy or Jigger.—A small tackle for general use; a double
block with a tail and single block with hook (Fig 89).
Watch Tackle or Luff Tackle.—Double hook block and single
hook block. If rove to advantage the power gained is 4, but if rove
to disadvantage the power gained is only 3 (Fig. 90).
NICHOLLS’S SEAMAN SHIP AND NAUTICAL KNOWLEDGE
Double Purchase.—Two double blocks. Power gained is 4 or 5
depending on which is the moving block (Fig. 91).
Three-Fold Purchase.—Two three-fold blocks. Power gained-
six or seven times (Fig. 92).
Fig. 91.
Fig. 92.
Fig. 93.
A Single Spanish Burton
gained—three times (Fig. 93).
A Double Spanish Burion.-
-Two single blocks and a hook. Power
-There are two forms of this purchase
PURCHASES
33
—Fig 94, by using three single blocks; Fig. 95 by using one double
block and two single blocks Power gained—five times The dis¬
advantage of this form of purchase is the very short travel of the lower
block as the whip block comes down and meets the lower block going
up.
How to reeve a three-fold purchase with the hauling and standing
parts of the fall in the middle sheave holes
Place the two blocks on deck with the tails of the blocks towards
each other. The one to take the hauling and standing parts of the
fall should have a good becket or eye m the tail, and should be laid on
its edge having the swallows up and down. (Call this No. 1 block )
The other one should be laid on its cheek having the swallows parallel
zo the deck. Lay the blocks close together and stand m line with them,
having No. 1 furthest away from you
Take the end of the fall from the coil and reeve it downwards through
the middle sheavehole of No 1 block, then from right to left through
the lower sheavehole of the other block, then upwards through the left
hand sheavehole of No 1 block, and from left to right through the top
sheavehole in the other block.
You should not go wrong now as there is only one vacant sheavehole
in No 1 block (the right hand one). Peeve downwards through this,
then from right to left through the middle sheavehole in the other block,
making the end fast to the tail of No. 1 block.
C
CMAift STOPPER OP wriRt
CHAPTER in.
STRENGTH OF ROPE.
The tern stress denotes the load put on material, and strain is the
molecular disturbance made evident by a change of shape or a fracture
of the material due to the stress which has been applied.
Stress comes before strain and the transition from stress to strain
introduces another factor called the “modulus of elasticity,” Young’s
modulus=stress divided by strain, within the limits of proportionality.
The term breaking or ultimate strength is the load or weight applied
to material when testing it to destruction.
Rope is made of hemp, manila and coir, their relative strengths
being in the order named. Splicing a rope reduces its strength about
one-quarter, and three stranded ropes are stronger than the corres¬
ponding size of four stranded ropes.
No rigorous rule can be laid down to arrive at the ultimate breaking
strengths of different sized ropes as so much depends upon the quality
of the natural fibre and the process adopted in its manufacture. The
size of a rope is expressed in terms of its circumference given in inches,
and a fair estimate of the breaking strength of good, honest hemp or
C 2
manila is obtained from the formula —, where C is the size of the rope.
3
Nor can a hard and fast rule be laid down to estimate the safe
working load for a given size of rope, but one-sixth of its ultimate
strength offers a good factor of safety in order to resist excessive stresses
due to sudden jerks on the fall. When an occasional lift is made there
Q2
is not so much wear and tear on the gear and — may he accepted as
giving a safe margin. /
Example .—Given a 3-inch manila rope, estimate its ultimate strength
and safe working loads.
G 2 9
Ultimate strength=—^ 1 = 3 tons.
3 3
34
STRENGTH OF ROPE
35
Working load =—=—= If tons for occasional lifts.
C 2 1 9
Working load =— X ————ton for continuous working,
o o lo
Exercise .—Find the breaking strength and the safe working loads
for occasional lifts and for continuous working of (a) 4-inch, (b) 44-inch,
(c) 5-inch manila rope.
Ans .
Breaking
Working load
Strength
Occasional Continuous
(«)
5J tons
2-2- tons
f tons
(6)
6f „
2*9 „
1J „
(c)
„
It may be required to find the size of manila rope suitable for a
given load and we then transpose the formula, for if the
C 2 _
working load = ~, then C 2 =seven times the load and C = ^/ 7 X load.
Example .—Find the size of the sma^est manila rope suitable for
loads of (a) 3 tons and (b) tons.
{a) Size of rope C=V 7Xload = V7X3 = V21 =4*6 inch.
Ans. For a 3-ton load use 4J-inch rope.
(b) Size of rope C= a/7x load — \/7x 1*5 = Vl0‘5 — 3J inch.
Ans . For a lj-ton load use 3£-inch rope.
To find the number of parts of smaller rope that are equal in strength
to one part of a larger rope we simply divide the ultimate strength of
the larger rope into the ultimate strength of the smaller one.
Example .—How many parts of a 2-inch rope are equal in strength
to a 5-inch rope?
If big 0 be the size of the bigger rope its ultimate strength will be
G 2
—•, and if small c be the size of the smaller rope its ultimate strength
will be
3
.\ number of parts =
ultimate strength G 2 ^ 3 C 2 5 2
ultimate strength
3 X c®
2 ®
= H
therefore, parts of 2-inch rope is equivalent in strength to one part
of 5-inch rope.
56 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
HOW TO HANDLE WIRE ROPE.
When uncoiling wire rope it is important that no kinks are allowed
to form, as once a kink is made no amount of strain can take it out,
and the rope is unsafe to work. If possible a turn-table should be em¬
ployed (an old cart wheel mounted on a spindle makes an excellent
one); the rope will then lead off perfectly straight without kinks.
If a turn-table is not available the rope may be rolled along the
ground.
In no case must the rope be laid on the ground and the end taken
over ot kinks will result, and the rope will be completely spoiled.
The life of wire rope depends principally upon the diameter of
drums, sheaves, and pulleys; and too much importance cannot be given
to the size of the latter. Wherever possible the size of the pulleys
should be not less than 700 times the diameter of the largest wire in the
rope, and never less than 300 times. The diameters of drums, sheaves
and pulleys should increase with the working load when the factoi
of safety is less than 5 to 1.
The load should not be lifted with a jerk, as the strain may equal
three or four times the proper load, and a sound rope may easily be
broken.
Examine ropes frequently. A new rope is cheaper than the risk
of killing or maiming employees.
One-sixth of the ultimate strength of the rope should be considered
a fair working load.
To increase the amount of work done, it is better to increase the
working load than the speed of the rope. Experience has shown that
the wear of the rope increases with the speed.
Wire rope should be greased when running or idle. Rust destroys
as effectively as hard work.
Great care should be taken that the grooves of drums and sheaves
are perfectly smooth, ample in diameter, and conform to the surface
of the rope. They should also be in perfect line with the rope, so that
the latter may not chafe on the sides of the grooves.
Wire is manufactured in various grades to suit different requirements,
the breaking strengths being given in tables issued by the makers; a safp
working load is about one-sixth of its ultimate strength.
A table issued by Messrs. Bullivant & Co. is given on page 37 but,
when tables are not available, an estimated breaking stress for the
flexible steel wire rope generally used for cargo work is given by 20%
WIRE ROPE
37
Flexible Steel Wire Ropes .'Galvanised)
Flexible Steel Wire Rope.
6 Strands, each 12 Wires
Extra Flexible |
Steei Wire Rope j
6 Strands,
^ach 24 Wires i
Special Extra
Flexible Steel Wire Rope
6 Strands, eacn
37 W.res
Special Make
«a
w
5
S
|
*5
33
Weight per Fathom
Approx
09
X
9
VI
t£>
jS
©
h
«
t- r;
S$l 5
» *“ ^2
« £ 5 *°
!3 5 fl-5
et
** X
u. O
4> S
fi.
Tf
'3
£
<9
CC
ec
s
sS
9
o
es
X
u ®
-*• a.
If ?
S I
Breaking Stum
X
X
9
JC
JS
fi*
£ !
SI
3
Z3
U
c3
I
o5
Inches.
Lbs.
Tons
Inches
Lhs
Tons |
;
Lbs. !
Tors
Toi.b
Inches
1
63
1 75
6
•ss
2 93 I
1 0
—
—
1
It
1 06
2 5
7}
1 31
4 45
1 56
—
—
n
1}
1 44
4 0
9
1 SS
6*7
2 i>
7 25
—
h
If
2-0
5*5
10}
2 5
8*75
2 8S
100
—
if
2
2 44
7 o
12“
3*5
11 85
4 0
130
—
2
2£
3 37
90
13}
4 5
14 6
4 SS
15 75
—
‘21
2}
4 59
120
15
5 44
18 55
5 SS
19 75
—
24
2f
5 23
15 0
m
6 23
21 95
7 0
24 0
—
2|
3
6 25
1" 0
18
7*63
25*7
8 25
29 0
—
3
7 06
2*2-0
19}
9*37
30 8
10 38
3* 5
—
Si
4
8 25
26 0
il
10*75
35-2
11 5
38 5
—
3h
3f
9 87
29 0
22}
12*19
41 1
13*3*
44 5
—
n
4
11*23
310
24
13 62
46*3
15 25
51*0
—
4
4£
12 35
36 0
25}
15 *69
52*9 !
17 12
58 0
—
H
n
13 44
39 0
27
17 75
58 6
19 0
6S 5
—
4H
4§
_
_
_
19 88
66*4
21*69
71 25
—
4|
5
_
_
_
22 5
74 2
24 38
79 25
—
5
5£
_
_
_
23 25
8*2 *sg
27 69
S7*75
—
5|
5l
_
_
_
24*5
91 55
31*0
96*75
—
5}
5|
_
_
_
—
33 75
10*1*75
—
6*
6
_
_
__
_
_
36 5
113*75
—
6
6£
_
_
_
_
—
42 5
132 0
—
6}
7
_
....
_
_
_
48 5
154*0
—
7
71
.
_
_
_
_
55 0
17**5
—
7*
8
_
. ..
_
63 0
19S-0
*202
S
9
_
_
___
_
_
79*0
25o*0
257
9
10
_
.
98 0
305*0
31S
10
11
_
- -
_
120*0
—
381
11
12
—
—
—
—
—
1420
—
455
* 12
In these Flexible Wire Rope Tables, which have been prepared by Messrs. Bollivant & Co,
Ltd. (who guarantee the above figures as regards new ropes supplied by them), the wire Is
calculated as taking a breakmsr stress of 90 tons to the square inch ; ropes made of wire which is
calculated above that will take a proportionately higher breaking stress
38
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
where 0 is the size of the wiie and. this fits in quite well with the ultimate
breaking stresses given for rope having 12 wires in each of the six
strands as given in Bullivant’s table, but 3C 2 gives a nearer approach
to its breaking strength when there are 24 wires per strand and 3JC 2
for the extra special rope with 37 wires per strand as indicated in the
table.
Q What would be the breaking stress of 2-inch wire ropes having
12, 24 and 37 wires in each strand?
Ans (12 wires) 2C 2 , 2x2x2=8 tons.
(24 wires) 3C 2 , 2x2x3=12 tons.
(37 wires) 3JO 2 , 2x2x3£=13 tons.
When referring to the breaking strength of wire rope we shall
assume the rule 2C 2 .
Example —Fmd the ultimate breaking strength, also the safe
worldng loads, of (a) 3-inch and (b) 3£-mch wire ropes.
(a) Breaking strength 2C 2 =2 x3x3=18 tons.
2 C 2 18
Working load —— = — =3 tons.
6 6
(b) Breaking strength 20 2 =2x3Jx3J=24£ tons.
2C 2 49
Working load —- = — = 4^ tons.
6 12
Example. —Find (a) ultimate breaking strengths, also (6) the safe
working loads of 2-inch, 4-inch, and 4J-mch steel flexible wire rope for
continuous working.
Ans. 2-inch wire (a) 8 tons, (b) 1J tons.
4-inch wire (a) 32 ,, (6) „
4£-inch wire (a) 40£ ,, (&) 6f „
Chain is made from steel or iron bars, forged or cast, and built up
link by link, every part of guaranteed chain being tested as there is
always the possibility of a chain having a link improperly welded,
burnt or otherwise defective, and this can be detected only by testing. <
The breaking strength of close link cargo chain is about twice its
proof load and the proof load is from 2 to 2J times the average working
load. The proof load is the stress applied to the chain when testing it
in a Proving House. The size of chain is the diameter of the iron
bar forming the link.
Breaking strength is about 30D 2
Proof load about 12D 2
TENSION ON PURCHASE PALLS
39
Safe working load about Jxl2Z) 2 =6Z) 2 , D being the number of
incLes in the diameter of the iron forming the common links, quoted in
commerce in eighths and sixteenths of an inch.
Example —Required the breaking strength, the proof load and the
working load of a §-mch iron chain.
Breaking strength 30-D 2 =30 x| xf=17 tons.
Proof load 12Z> 2 =12 x-fxf=6f tons
Working load 6Z) 2 =6 xf Xf=3*4 tons.
Another rule to find the approximate load for iron chain is^ where
d is the size of the chain in eighths of an mch.
Thus i-inch chain is four-eighths and —
10
4x4
10
= 1*6 tons as a
safe working load.
To find the smallest size of chain to lift a given load we can apply the
d 2 , _
same rule, namely, load = — .*. d = V 10 X load
Example —Required the smallest size of chain for lifting loads of 2|
tons and 5 tons
d 2 = 10 xload=10 X2*5 tons =25 d=5-eighths
Use a |-inch chain for 2i-ton loads.
d 2 = 10 X load=10 X 5 tons = 50 d=7-eighths.
Use a i-inch chain for 5-ton loads.
The Frictional Resistance of a purchase increases with the number
of sheaves, and an allowance of about one-tenth of the weight to be
lifted for every sheave in the purchase is usually added to the weight
when estimating the additional force that must be exerted to raise the
weight. The theoretical advantage is found by counting the parts
of the fall at the moving block. When the single block in a luff tackle
is the moving one it is said to be rove to disadvantage and the power
gained is three, but if the double block is the moving one it is rove
to advantage and the power gained is four; that is to say, a pull, or
force, of 1 ton should balance a weight of 4 tons. But in a luff
tackle rove to advantage there is the weight of the rope and blocks,
4
also the friction of three sheaves to overcome, so 3 X — tons = *1*2
10
tons for friction and this should be added to the 4-ton weight, making the
total load on the purchase about 5*2 tons. The weight, however,
will be distributed almost equally amongst the several parts of rope in
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
40
the purchase at the moving block. There are four parts in the lufl
5*2
tackle when rove to advantage so — tons gives 1 3 tons as the load on
each part of the purchase.
nW
The weight + friction may be expressed as W -J—— where W is
the weight to be lifted and n the number of sheaves, thus in the above
nW 3x4
example, W -)- =4-1 -—- = 52 tons.
r 10 10
Example. —A weight of 4 tons is to be lifted with a gun tackle, find
approximately the pull on the hauling part if rove to disadvantage.
Arts . There are 2 sheaves and 2 parts of rope (Fig. 1). Total
nW 2x4
load=weight+friction=TF+-j^-=4H—~4-& tons. Pull on hauling
4*8
part = —— = 2*4 tons.
2
“There is less friction with sheaves of larger diameter than ol
smaller diameter and with thin rope than with thick rope, so
the maximum advantage is gained by using large sheaves and
strong small sized rope. Fast winding adds to the tension on
each part of rope and there is less tension when lowering the
weight than when it is merely hanging on the purchase.”
Exercises.
1. A weight of 12 tons is being lifted with a three-fold
purchase, find the total load and the pull on the hauling part, when
(a) rove to disadvantage, (b) rove to advantage.
Ans 19*2 tons, (a) 3*2 tons, (b) 2*75 tons.
2. Find the total load on a double purchase and the pull on the
hauling part of the fall when rove to advantage and lifting 20 cwt.
Ans . 28 cwt. and 5*6 cwt.
3. A treble purchase rove to advantage, lifting 40 tons. Find the
total load and the pull on the hauling part.
# Ans. 64 tons and 9^ tons.
4. Lifting a weight of 15 tons with a luff tackle rove to dis¬
advantage, find the total load and the pull on the hauling part.
Ans. 19*5 tons and 6*5 tons.
MECHANICAL ADVANTAGE
41
The illustration of Messrs. Davey & Co. shews the experimental
working stresses on the various parts of a tackle with a load of 1 ton.
The pull on the hauling part may be found approximately from the
general formula, but it is evident that the . stress will vary on aD
parts with the speed of hoisting or lowering. Let us apply the
formula and compare our answers with the tested loads given in
the illustration.
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
42
An approximate connection between the weight being lifted and rtie
stress on the hauling part of a purchase is given by the formula
SxP=W+
10
where S is the stress or pull on the hauling part
P, the theoretical power of the purchase
W, the weight being lifted
rt, the number of sheaves in the purchase
nW
-jjj- is the allowance for frictional resistance
The theoretical power or mechanical gain is equal to the number of
sheaves when the hauling part of the rope comes off the standing block,
but it is increased to the number of sheaves plus 1 when the hauling
part comes off the moving block. In the above equation P=n, if the
purchase is rove to disadvantage, and P=n +1 when it is rove to
advantage.
Example .—A 12-ton weight is to be lifted with a three-fold purchase
rove to advantage; find the tension on the hauling part of the fall and
the size of manila rope to use. There is a lead block at the masthead.
S is required. P=7, TT=12 tons, w=7 sheaves
s x p=w+ nW
oX7=12 +
10
7X12
120+84
10
10
204
'To
204 1
S = X-=3 tons, the pull on the hauling part
The size of rope 0 = V7xload
= Vfx3
= 4| inch
Tension on hauling part is 3 tons and use a 4+inch manila
rope.
Example .— The Single Purchase. —See Fig. 1.
A. The pull on hauling part is given as 12 cwt.
5xP=ff+
nW
Sx 2 = 20 -
2 x 20
= 24
10 1 10
5=12 cwt. which is the same‘as given.
> B. The stress on the top hook when hoisting is given as 33 cwt. It
is the load plus the pull on the hauling part plus the weight of the tackle,
MECHANICAL ADVANTAGE
43
that is 20 cwt.+12 cwt. =32 cwt, leaving 1 cwt for the weight of the
tackle.
D. The stress on the becket when hoisting is given as 9| cwt. It
is evidently half the load less half the weight of the tackle as the top
block is supported by the beam, and half the load is supported by the
other part of the fall, that is,
| load—£ weight of tackle
10 cwt —4 cwt = cwt. as the stress on the
becket, which agrees nearly with the tested stress.
Example .—The Luff Tackle.— See Fig. 1.
A . The pull on the hauling part is given as 9 cwt
S X P=F+^ S X 3 =20+^-^ = 26
&=8*7 cwt., which is nearly the same
B The stress on the upper hook is given as 30J cwt. It is the load+
the pull on hauling part+the weight of the tackle, that is
20 + 8 7 = 28*7 cwt. leaving 1*6 cwt. as the weight of the tackle.
D. The stress on the becket at the lower block when hoisting is
given as 5J cwt. It is approximately one-third the load as there are
three parts of rope supporting the load, less half the weight of the tackle.
* i load — \ tackle = stress on becket.
6*7 cwt.— *8 cwt. =5*9 cwt. which is slightly over the
test stress.
The other tackles may be worked out in a similar way.
Example .—What resistance could be overcome with a three-fold
purchase by applying a pull of 2 tons to the hauling part (no lead blocks).
jS= 2 tons, P=6, ft=6 sheaves. W is required
s X P=W + —
2X6 = F+- =
6PF 10F + 6FP
10
1 m
10
16 W = 120 W =— = 7£ tons
16
The actual weight would be 7£ tons, but the total resistance (weight
plus friction) would be greater. Add for friction one-tenth of the
6
weight for each sheave, viz., 7*5 tons X — =4*5 tons.
Total resistance is 7*5+4*5=12 tons
44
NICHOLLS S SEAMANSHIP AND NAUTICAL KNOWLEDGE
When a second tackle is hooked on to the hauling part of another
tackle the power gained by the combination of the two purchases is
approximately equal to the product of their powers.
Example .—A 10-ton load is being lifted with a two-fold purchase
rove to disadvantage, (power 4) with a gun tackle rove to advantage,
(power 3) secured to its hauling part. Required the stress on the
hauling part of the gun tackle
S is required. P=4 X3=12.
<SXP=TF+^?
Sxl 2 = 10+^^=16
W=10 tons. w=6 sheaves
16
tons pull <
Figures 2 and 3 shew a test load of 42 tons on a Mannesmann tube
derrick with a five-fold purchase rove to advantage. The fall leads up
from the lower block through a lead block at the derrick head, and
another at the masthead, and down to a winch. It is required to find a
suitable size of wire.
The power gained is 11. There are 12 sheaves, but as the two lead
blocks offer a straighter lead for the wire their resistance will be less
than the others and they may be taken as one block, so now we have
11 sheaves.
Tension on the hauling part is got from the equation—
SxP = W +
nW
To
S X11 =42+(ll X 42-MO) =88*2
$=88*2-Ml =8 tons
Special extra flexible steel wire rope is used for heavy lifts the
working load of which is about one-third of the breaking strength so
2 C 2
if the working load 8 tons =
then 2C 2 —24, and 0=Vl2=3J
A 3J-incb wire would be suitable. In practice, however, a 3-inch
wire would probably be used, as the general formula is not quite so
applicable to higher purchases running over sheaves of big diameter.
Nor is it desirable, unless for strength and.smooth running, to use a
MECHANICAL ADVANTAGE
45
greater power than a foar-fold purchase as the extra weight of tackle
and frictional resistance neutralise the mechanical advantage of theory.
#• \
Fig. 2.—Testing a Derrick,
Differential pulley purchases (Fig. 4) are' extremely powerful.
There is usually one in the engine room travelling on a h«aw beam in
46
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
the skylight for lifting the cylinder covers and pistons. The upper
block has two sheaves rigidly attached to each other but differing
slightly in diameter. An endless chain passes over the sheaves the
rims being made with "snugs” to take the links of the chain to prevent
it from slipping. The power gained is given by where R is the
R —r
MECHANICAL ADVANTAGE
47
radius of the larger sheave and r the radius of the smaller one in the
upper block.
Screw chain hoists are sometimes used for lifting heavy weights by
hand power (Fig. 5.) The gearing in the system illustrated consists
of pulleys of different diameters The hauling or hand chain passing
over the flywheel is endless. This flywheel has an axle with a worm
screw which engages with the neiicai teeth of the big wheel. A sprocket
Fig. 4. Fig. 5.
is keyed to the axle of the toothed wheel and over this sprocket is seen
the stout lifting chain which, in the illustration, is led through a moving,
block to increase the purchase, the standing end of the chain being
shackled to the framework of the differential gearing.
It works as follows:—The flywheel is turned by the hand chain,
which turns the screw axle, which turns the toothed wheel, which turns
the'sprocketed axle and thus moves the stout lifting chain and raises the
weight.
*8
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Questions.
1. Name the different fibres used m making rope and that which is
most commonly used in merchant ships
2. A new coil of wire is to be uncoiled, how would you go about it ?
3. What precautions should be taken with working wire ropes to
ensure for them as long life as possible?
4. Write down an equation to express the approximate breaking
strength of wire rope.
5. What would you consider a safe working load for a 3-inch wire
cargo fall?
6. How is chain measured? Distinguish between the breaking
strength, the proof load and the safe working load of chain.
7. What do you understand by a purchase being rove to
“advantage” and to “disadvantage”?
8. What is the theoretical'power gained by using a gun tackle, a
luff tackle and a double purchase? If a load of 2 tons is suspended
from each purchase what will be the tension on the hauling part o*
each?
9. Describe a form of differential pulley purchase.
10. A weight of 30 tons is to be lifted with a three-fold purchase,
rove to advantage, with lead block at the derrick end and another
at the masthead. Required the tension on the hauling part and a
suitable size of steel flexible wire. (Use r breaking strength as a safe by
factor.)
Ans. Tension is 7J tons. Use a 4f-inch wire.
11. A weight of 25 tons is to be lifted with a two-fold purchase
rove to advantage, and a leading block at the derrick end and another
at the masthead. Required the size of wire to use.
, Ans. Tension on hauling part 1\ tons. Use 4f-inch wire.
12. A weight of 10 tons is to be lifted with a two-fold purchase,
rove to disadvantage, and one lead block. Required the size of wire.
Ans * Tension on hauling part 3f tons Use a SJ-inch wire.
CHAPTER IT.
THE RIGGING OF A STEAMSHIP.
The figure shows the rigging of a steamship’s mast. There are three
shrouds on each side of the lower mast fitted with ratlines, and a
backstay on each side of the topmast, a topmast stay leading down
forward to nearly the stemhead and a forestay, with a staysail on it,
set up by means of a bottle screw to a ringbolt on the forecastle deck.
This ship has an additional stay from the iowermast-head to the after
end of the forecastle to be used as a preventer stay to stiffen the mast
when heavy weights are being lifted at No. 2 hatch with the big derrick,
which is seen up-ended abaft the mast This stay is disconnected
when cargo is being worked at No. 1 hatch.
When only three shrouds are fitted on each side they consist of a
single one and a pair. The single one is generally called a “swifter ”
They go over the masthead in the following order*—Starboard swifter,
port swifter, starboard pair of shrouds, port pair of shrouds, stay.
When four shrouds are fitted on each side they consist of two pairs.
The starboard forward pair goes on first and then a pair on each side
alternately. Stay last. All shrouds and the stay are single pieces of
wire and are generally shackled on at the masthead. This being the
case, it does not matter which is shackled on first. The average size
of wire is about 4 inch for the shrouds and a little heavier for the stay.
Shrouds are parcelled and served. See page 543.
The Parcelling and Service are always started at the bottom and
worked upwards. The parcelling is put on with the lay of the rope,
the serving is done against the lay. See page 612.
A Hounds Band is generally riveted round the masthead. This
has the proper number of eyes welded on to it to which are shackled
the shrouds and stay. Another arrangement for securing the rigging
at the lowermast-head is by means of two pieces of angle bar, bent
and riveted round the mast a few inches apart. One flange of each
is bent to a suitable angle to form two lugs, holes being drilled in these
to a proper alignment. The eyes of the shrouds and stay are placed
49
CHAPTER IV.
THE RIGGING OF A STEAMSHIP.
The figure shows the rigging of a steamship’s mast. There are three
shrouds on each side of the lower mast fitted with ratlines, and a
backstay on each side of the topmast, a topmast stay leading down
forward to nearly the stemhead and a forestay, with a staysail on it,
set up by means of a bottle screw to a ringbolt on the forecastle deck.
This ship has an additional stay from the lowermast-head to the after
end of the forecastle to be used as a preventer stay to stiffen the mast
when heavy weights are being lifted at No. 2 hatch with the big derrick,
which is seen up-ended abaft the mast. This stay is disconnected
•when cargo is being worked at No 1 hatch.
When only three shrouds are fitted on each side they consist of a
single one and a pair. The single one is generally called a “swifter.”
They go over the masthead in the following order:—Starboard swifter,
port swifter, starboard pair of shrouds, port pair of shrouds, stay.
When four shrouds are fitted on each side they consist of two pairs.
The starboard forward pair goes on first and then a pair on each side
alternately. Stay last. All shrouds and the stay are single pieces of
wire and are generally shackled on at the masthead. This being the
case, it does not matter which is shackled on first. The average size
of wire is about 4 inch for the shrouds and a little heavier for the stay.
Shrouds are parcelled and served. See page 543.
The Parcelling and Service are always started at the bottom and
worked upwards. The parcelling is put on with the lay of the rope,
the serving is done against the lay. See page 612.
A Hounds Band is generally riveted round the masthead. This
has the proper number of eyes welded on to it to which are shackled
the shrouds and stay. Another arrangement for securing the rigging
at the lowermast-head is by means of two pieces of angle bar, bent
and riveted round the mast a few inches apart. One flange of each
is bent to a suitable angle to form two lugs, holes being drilled in these
to a proper alignment. The eyes of the shrouds and stay are placed
50
NICHOLLS’s SEAMANSHIP AND NAUTICAL KNOWLEDGE
between these lugs, each one
through it. The bolts have ;
end to keep them in position.
being secured by a heavy bolt shipped
■ g° od head and forelock at the lower
afterwards. The forestay is
on the forecastle-head deck
is set up first and the shrouds
sometimes set up “on its end” to hearts
or on the stemhead, In other ships it is,
RIGGING OF STEAMSHIPS
51
set up by means of heavy bottle
screws to good eyebolts in the same
positions
The rigging at the topmast-head
is shackled on. An iron hounds
band is fitted round the masthead
on to which are welded four eyes.
One is on the foreside for the stay,
two a little abaft the middle part of
the mast for the backstays, and
one on the after side for the jumper
(triatic) stay. This is generally
shackled on to one topmast-head, led
down through a fitting at the other
mast set up with a bottle screw or
lanyard.
In old ships a grommet was
beaten down on to the hounds of
the mast, and large eyes spliced in
to the stay and backstays which go
on over the masthead. Stay first,
then starboard and port backstays.
* The weight of the topmast rests
on an iron fid, a square bolt which
goes through the heel of the top¬
mast, each end resting on the
trestle trees. The trestle trees are
two short fore-and-aft angle bars
riveted to the sides of the lower
mast at the level of the fid.
Telescopic Mast.—When a tele¬
scopic topmast is first fitted, a short
piece of wire or chain is rove through
the sheave hole in the heel and made
fast at each side of the lower mast¬
head. To send the mast down . Take
the end of a wire mastrope aloft,
marry it on to this short piece, haul
it through the sheave hole and
make fast to the lowermast-
Fig. 2.—A Telescopic Topmast.
52
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
head. Many ships are fitted with a permanent sheave between two
cheeks at the lower masthead for this rope to reeve over. Should
this not be the case a smgle block must be hung at the masthead and
the mastrope rove through it Take the mastcoat off and remove the
wedges. Come up the backstays, stay, and jumper stay Lead the
mastrope to the winch and take the weight off the fid. Unship the fid.
Lower the topmast down inside the lowermast until the hounds band
is at the lowermast-head or in the position required. If the backstays
and stay are not sent down on deck they can be brought in to the mast
and stopped to it out of the way. The jumper stay can be taken adrift'
if necessary.
Should there be a signal yard or lamp bracket they must be sent
down to enable the mast to be lowered sufficiently. Do not unreeve
the mastrope.
To send down a Signal Yard. —Hang a good single block at the
topmast-head. Take the end of a yardrope aloft, reeve it through
this block from aft forward, and make it fast round the quarter of the
yard. Take to the winch, heave a very small strain on it and make
fast. /
Take the yard adrift from its fitting. It does not swing on a truss
or parrel in the manner of an ordmary yard. When it comes adrift
the yard will cockbill on account of the yardrope being made fast
Tound the quarter. A rope lashing may be useful while doing this
part of the job. Lower the yard down on deck.
To send up a Telescopic Topmast. —See that the stay and backstays
are shackled on in their proper places and that they are all clear for
running when you hoist away. Heplace the jumper stay, if it has been
taken adrift and reeve off the signal halyards. The mastrope having
been left rove when the topmast was sent down, it would be ready for
use. Take it to the winch and heave the mast up a bit. Fix the signal
yard in position if one is fitted, also the lamp bracket. Unless the
signal yard is an unusually heavy one it is not necessary to make another
job by sending it up afterwards. Heave away again on the mastrope,
and when high enough vast heaving and ship the fid. Ease up the
mastrope. Wedge the mast and put on the mastcoat. Cast the end
of the mastrope adrift, marry a short piece of wire or chain on to it,
haul it through and leave the ends made fast at each side of the masthead
so that they are ready for use when required again. Set the stay up,
then the backstays and jumper stay.
It may be required at some time to unship a telescopic topmast
54
NXCHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
and send it down on deck. The best and quickest way would be to
make use of a shore crane. If one is not available then it would be
necessary to lash a suitably long spar to the end of a derrick to be long
enough to reach well above the lowermast-head. Send down the signal
yard, if any, also lamp bracket, etc. Take off the mastcoat and lift
out the wooden wedges. Slacken up the rigging screws, unshackle
the stays and backstays at the masthead and send them down with a
gantline. The end of a wire, rove through a block lashed to the top
end of the up-ended derrick, is now lashed to the topmast above its
centre of gravity. Lead the wire to a winch and heave away gently,
take out the fid, unreeve the “dummy” heel rope, and when the heel
is clear of the lowermast-head lower the topmast down on deck.
It would be well to have a slack turn of a preventer lashing round
the heel of the topmast and the up-ended spar in case the mast might
topple over if the wire has not been lashed high enough up.
The stump of a broken topmast could be lifted out in the same way;
some spike nails driven in about the lashing would prevent the gantline
from slipping.
Fitted Topmast.—When sending up a fitted topmast lay the mast on
deck head forward, after side of mast uppermost. Hang a top block at
the lower cap. Reeve the mastrope through this block from aft forward,
down between the trestle-trees and through the collar of the lower stay if
the stay goes over the masthead, and overhaul the end down on deck.
Make the wire fast to the topmast-head and lead the hauling part to a
winch, heave away and get the topmast up and down on the fore side
of the lowermast. Hang off the mast with a lashing, let go the wire
and reeve the end through the sheave hole in the heel of the mast, then
up between the trestle-trees and collar of the stay and make it fast
on the other side of the lower cap. The mastrope is now doubled,
heave up and when the topmast-head is entered through the lower cap
put the stay and backstays on. If these go over the masthead the
stay goes on first, then the starboard and port backstays. Heave
away again on the mastrope and when high enough put the fid in
The ends of the fid rest on the trestle-trees on each side of the mast.
Come up the mastrope and unreeve it. Set the gear up, stay first.
Send the top block down.
When sending down a fitted topmast hang a top block at the lower
nap. Reeve the end of the mastrope through it ’from aft forward, then
through the sheave hole in the heel of the mast and make it fast on the
other side of the cap. Come up the backstays and stay, also the jumper
Fig. G,—lligging and Deri lcks. Telescopic Topmast Housed.
56
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE .
on deck as required. Bend a single gantline to the head of the topmast
and lower it down on deck with it. Tidy up the gear.
Derricks.—To rig derricks for discharging overside, keeping one as a
standing derrick and the other as a yardarm derrick. Shackle on the guys
and cargo gins, reeve off the runners, shackle on the^ cargo hooks. Top
the derricks up into position, one over the hatch and the other guyed
out to the side of the ship. If they are fitted with a chain span instead
of a topping lift, you will have to rig a tackle from the masthead with
which to lift them up. When you have got each one high enough
shackle on the chain span, then by easing up the tackle let the span
take the weight. See that all the guys are led away clear and set well
taut to maintain both derricks in their proper positions.
Figure 5 shows four 5-ton derricks with their heels mounted on a
table, and a 20-ton derrick with its heel stepped into a special fitting
on the deck. Note the cargo blocks, spans, falls and guys. The
telescopic topmast is housed. •
Questions
(1) Describe the rigging on a steamship’s mast, how it is secured
at the masthead and the arrangements made for setting it up tight.
(2) How is any rope parcelled and served and what is the purpose
of this dressing on the rope?
(3) Name the parts of a mast.
(4) In what order is the rigging of a mast set up?
(5) Describe how you would house a telescopic topmast.
(6) How would you go about sending down a signal yard?
(7) Send up a telescopic topmast.
(8) Describe how a telescopic topmast could be unshipped.
(9) Take out the stump of a broken telescopic topmast.
(10) You are in a steamer fitted with a fitted topmast, how would
you send it down on deck?
(11) Describe the sending up of a fitted topmast.
(12) Describe how you would go about rigging derricks, hoisting
them up, and getting as much as possible done to be ready for dis¬
charging cargo as soon as the ship is berthed, the ship just entering the
port.
(13) The ship has just finished loading, stevedores’ gang have left,
describe how you would get everything into sea position, decks cleared
up ready for getting under way.
STEAMSHIP SAILS
57
STEAMSHIP SAILS
This sail is set on a traveller abaft the mast. The traveller is
generally of T section, with iron hanks which can travel up and down
on it. Sometimes it is an iron rod held by “dogs.”
The head of the sail is shackled to an eyebolt at the masthead. The
tack is secured with a shackle or lashing.
The luff of the sail is bent on to the hanks with “robands” often
called “rovings” (pieces of spunyam).
Pieces of 2J inch manila rope called “brails” are seized at the middle
of their lengths on to the after side of the leech. The two ends of each
brail are rove through brail blocks shackled to an eyebolt on the mast on
each side of the traveller, and led down on deck, forming the hauling parts.
The sheet may be a luff tackle or gun tackle purchase.
To set the sail. —Loose it, let go the brails, haul aft the sheet.
58 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
To take it in.—Man the lee brails. One hand take in the slack of
the weather ones Ease away the sheet. Brail it close in and make it fast.
This is another form of trysail often used in steamers.
It runs up and down the traveller instead of having the head secured
at the masthead.
It is fitted with halyards for hoisting, and a downhaul for hauling
it down, no brails of course being necessary.
In shape it is about the same as the standing trysail shown and
explained on the preceding page.
To set it.—Loose the sail, let go ,the downhaul, and take aft the slack
of the sheet. Hoist away, sweat the luff up tight. Trim the sheet.
To take it in.—Man the downhaul, let go the halyards, ease the sheet
off and haul the sail snug down. Pass the gaskets.
ST HAM SHIP SAILS
L—Head
m (Leech or
iff 'After leech *
Diagonal hand
Pownhaui
%sX
Fig. 8.—Staysail.
The above illustration does not represent a staysail when it is set
on the stay, but shows the shape of the sail together with the names of
its different parts and the gear belonging to it.
Note the round of the luff. This would not be seen when the sail
is set, as the luff rope would conform to the curvature of the stay.
The cloths are parallel to the leech and the foot.
The diagonal band covers the seam joining the two parts, and
strengthens the sail against the pull of the sheet. This diagonal method
of making a sail is a better one than that of having all the cloths parallel
to the leech, as the sail is stronger and keeps its shape better.
60
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
To set it.—Loose the sail, let go the downhaul and haul the slack o
the sheet aft. Man the halyards and “swig” the sail up tight. Trin:
the sheet.
To take it in.—Man the downhaul, and when all is ready let go the
halyards. Haul the sail down, slacking the sheet away as necessary,
Let go the sheet and make the sail fast.
Figure 9 shows an ordinary spanker as used with a standing gaff
and spanker boom.
The luff is bent to a jackstay abaft the mast, and the head to rings
on the gaff. The rings are generally made of galvanised iron. There is
a good “throat” and “tack” lashing. It is fitted with head outhaul
and downhaul, also with a foot outhaul and brails. These brails are
fitted as for a steamer’s trysail.
STEAMSHIP SAILS
61
To set it.—Hook the foot outhaul on to the clew and haul the slack
o at, easing off the brails and head downhaul. Pull the head up tight and
“swig” the foot out well. Attend to the “vangs” and “boom sheets.”
To take it in.—Let go the head outhaul and haul the head snug
down first slacking away some of the foot outhaul if necessary. Man
the lee brails, slack away the foot outhaul, finally lettmg go, and brail it
close in Pass the gaskets. Haul the gaff and boom amidships.
Note .—Some vessels have a hoisting or “leg of mutton” spanker
This is practically the same as a steamer's trysail.
PARTS OF SAILS, ETC.
Define the meaning of the following terms —
Head of a sail.—The upper corner of a trysail or staysail. It is
fitted with a galvanised iron thimble to take the halyards or head
lashmg or shackle.
If the trysail sets on a gaff it is that part which is stretched along
the gaff that is, the whole upper edge of the sail
The head of a spanker is the upper corner of a “leg of mutton”
fepanker, but the whole upper edge of the sail if it is one which is hauled
out along a gaff.
The whole upper edge of a square sail is also called the head.
Foot of a sail.—The lower edge of any sail.
Tack of a sail.—The lower comer of a staysail or jib. The lower
forward corner of a spanker, or of a trysail which sets with its foot in a
horizontal direction.
When the yards of a square-rigged vessel are taken well forward, the
weather clew of each “course” is bowsed down with a chain or tack
tackle. It is then called its “tack.”
Clew.—The after corner of a fore-and-aft sail, also both lower comers
of a square sail.
Leech.—The edge at the sides of a square sail. All square sails have
two leeches.
After leech (also called leech) the edge of a fore-and-aft sail contained
between the head and the clew.
In the case of a fore-and-aft sail which sets on a gaff, it is the after
edge of the sail.!
Throat of a sail.—The upper forward corner of a spanker or of a
trysail which sets on a gaff. It is fitted with a shackle or “throat
iashing” to secure it in its proper position.
The upper forward comer of a boat's lugsail is also called the “throat.”
STEAMSHIP SAILS
61
To set it.—Hook the foot outhaul on to the clew and haul the slack
out, easing off the brails and head downhaul. Pull the head up tight and
“swig” the foot out well Attend to the “vangs” and “boom sheets.’ 5
To take it in.—Let go the head outhaul and haul the head snug
down first slacking away some of the foot outhaul if necessary. Man
the lee brails, slack away the foot outhaul, finally letting go, and brail it
close in Pass the gaskets Haul the gall and boom amidships.
Note —Some vessels have a hoisting or tf leg of mutton” spanker.
This is practically the same as a steamer's trysail.
PARTS OF SAILS, ETC.
Define the meaning of the following terms —
Head of a sail.—The upper corner of a trysail or staysail. It is
fitted with a galvanised iron thimble to take the halyards or head
lashing or shackle
If the trysail sets on a gaff it is that part which is stretched along
the gaff, that is, the whole upper edge of the sail.
The head of a spanker is the upper corner of a “leg of mutton”
Spanker, but the whole upper edge of the sail if it is one which is hauled
out along a gaff
The whole upper edge of a square sail is also called the head.
Foot of a sail.—The lower edge of any sail
Tack of a sail.—The lower comer of a staysail or jib The lower
forward corner of a spanker, or of a trysail which sets with its foot in a
horizontal direction.
When the yards of a square-rigged vessel are taken well forward, the
weather clew of each “course” is bowsed down with a chain or tack
tackle. It is then called its “tack.”
Clew.—The after corner of a fore-and-aft sail, also both lower comers
of a square sail.
Leech.—The edge at the sides of a square sail. All square sails have
two leeches.
After leech (also called leech) the edge of a fore-and-aft sail contained
between the head and the clew.
In the case of a fore-and-aft sail which sets on a gaff, it is the after
edge of the sail.f
Throat of a sail.—The upper forward comer of a spanker or of a
trysail which sets on a gaff. It is fitted with a shackle or “throat
lashing” to secure it in its proper position.
The upper forward comer of a boat’s lugsail is also called the “throat.”
62
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Peak of a sail.—The upper after corner of a spanker or of a trysail
which sets on a gaff. It may be secured in position by a lashing, oi
hauled out with a “head outhaul.”
The upper after corner of a boat’s lugsail is also called the “peak.”
Gaff peak. —The upper and after end of a gaff.
Roach of a sail.—Arch or curve in the foot and leeches of square sails.
Round of a sail.—The convex shape given to the luff and foot of a
jib or staysail.
Gore cloths. —Cloths cut at an oblique angle to form the “roach”
or the “round.”
Diagonal band. —A tapered strip of canvas extending diagonally
across a fore-and-aft sail from the clew to the luff rope. It covers the
seam joining the upper and lower parts of the sail and strengthens it by
fortifying it against the pull of the sheet.
Reef band. —The canvas band sewn across a sail in the way of the
reef points.
Reef points. —Pieces of point line (good manila) which are fitted in
eyelet holes worked through the cloths and reef bands of sails. They
are sewn to the bottom of the eyelet holes in fore-and-aft sails but to’
the top in square sails. The reason foT this is that fore-and-aft sails are
reefed on the foot, but square sails .are reefed on the head.
Linings. —Lengths of canvas worked along the edges of sails before
the rope is put on. The outer edge of the lining is secured by the roping
of the sail, the inner edge being sewn down with a flat seam. Linings
on a steamer’s sails are about 1 foot wide except for about 5 feet up
from the clew and 3 or 4 feet along the foot where they are generally
given a full cloth.
Tabling. —A sail having been cut out and the cloths sewn together,
the edges all round are turned back for a width ©f about 4 inches and
sewn down flat. That part of the canvas which is turned back is called
the “tabling.”
CANVAS, ROPE, SAILS, Etc.
Ordinary British sail canvas is made of flax, the best qualities being
“all long flax.” American canvas is made of cotton.
The threads running lengthwise are called the “warp,” apd those
.running crosswise are called the “weft.” The finished edge of the
canvas is called the “selvedge.”
The stoutest canvas is No. 1, the next No. 2, the lightest in general
use being No. 6.
CANVAS, ROPE AND SAILS
63
Sail canvas is 2 feet wide, made up in bolts of about 42 yards. The
length in each bolt is generally stencilled on the outside to the nearest
quarter of a yard. A bolt of No. 1 canvas weighs 48 or 49 lbs.
Tarpaulin canvas is hot of such good quality as sail canvas, being
generally made of second grade flax. The texture is coarser and rougher,
the usual width being 2 ft. 6 ins. or 3 feet
Boltrope is good quality three stranded rope made of the best hemp.
It is manufactured from the longest and finest yams, and tarred with
best Stockholm tar and oil. It is laid up much softer than ordinary
hemp rope, and is more supple and pliable. It is used for roping sails.
Cable laid rope is a good quality manila or hemp used for trawl
warps, and fore and main sheets in sailing vessels. It consists of three
ordinary right handed ropes laid up left handed. It is therefore nine
stranded.
A steamer’s trysail or staysail is made of heavy canvas No. 1 or 2
for the cloths. The seams are sewn with double seaming twine. Roping
twine is used for sewmg the boltrope round the edges. The eyelet holes
along the luff have a small grummet sewn round them, or are fitted with
brass eyelets which are simply stamped in: 2J or 3-inch boltrope is
used for roping the luff and after leech, the foot rope generally being
a little smaller. About 4 feet of the rope on the foot and about 5 feet
of the leech rope is about an inch larger in size next to the clew, being
joined to the smaller rope by means of a sailmaker’s splice. Galvanised
iron thimbles are worked in at the head and tack, and a heavy galvanised
iron ring at the clew.
Flexible steel wire is now superseding boltrope in all kinds of
sail making.
A steamer’s sails, if she has any, are principally for steadying her in a
seaway. With a strong beam wind the side pressure on the sails
moderates the rolling. They also have some propelling power, and thus
help her along. They are very useful in the case of an accident to the
engines or propeller.
When bending a standing trysail bring it along to the foot of the mast,
and open it out. Fake it down on the deck, having the tack underneath
and the head on top. If the brails are not on the sail, middle them and
seize them on to the after leech. Eyelet holes are worked in the sai)
for passing the seizings.
Reeve a gantline through a block at the masthead for hoisting it up.
-Take the hanks oft the traveller abaft the mast and bend one on
to each of the eyelet holes in the luff. Hoist away slowly by means of
64
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
the gantline, putting each hank back on the traveller as the sail goes up.
Shackle the head of the sail on to the eyebolt at the masthead. Reeve
the brails through the brail blocks and pass the ends down on deck
Tighten the luff by bowsing down on the tack and securing it.
If the sail is required for immediate use, shackle the sheet on and
set the sail by hauling it aft and making it fast If not, haul all the
brails tight and pass the gaskets
When bending a hoisting trysail carry it along to the foot of the mast
and open it out. Fake it down on deck, having the tack underneath
and the head on top.
Take the hanks off the traveller and bend one on to each of the
eyelet holes in the luff of the sail, also one on to the head. Shackle the
halyards on and make the downhaul fast on to the head cringle. Hoist
away slowly with the halyards, putting the hanks back on the traveller
as the sail goes up Shackle the tack on to an eyebolt in the mast,
also shackle the sheet on to the clew of the sail.
Set the sail by sweating the luff up tight and hauling the sheet aft.
If not required at once, haul it down and make it fast.
When bending a staysail open it out at the foot of the stay Takq
hold of the head, and fake the luff down on the deck, this will leave
the tack on top.
Bend a hank on to the tack cringle, one on to each eyelet hole,
working upwards, and one on to the head cringle.
Shackle the halyards on to the head cringle, and the tack pendant
at the foot of the stay on to the tack cringle. Bend the downhaul on
to the head cringle by means of a buntline hitch or inside clench. A
shackle or clip hooks would cause too much chafe. Shackle the sheet
on to the clew.
If the sail is not to be set at once, haul it snug down and make it fast.
Fore-and-aft sails are roped on the port side in order to establish
a standard practice, and to enable the head to be distinguished from
the tack. Regarding efficiency one side is as good as the other.
When rolling up a fore-and-aft sail for stowing away it is made up
on the after leech, which is stretched tight rope to the deck. Carry
the tack in and lay it along the after leech, smooth the canvas out
evenly, roll the sail up snug. Use manila yarns for stops.
Questions
• (1) Describe a steamer’s standing trysail, and (a) name all the parts,
(b) how you would set it, ( c ) how you would take it in and furl it.
CHAPTER V.
BOAT SAILING.
The illustration (Fig. 1) shows a life-boat fitted with a “standing
lugsail.” It is also a free-footed sail (no boom). It differs from the
“dipping” lug insomuch that it is not dipped each time the boat ia
put about, the yard and sail remaining always on one side of the mast;
that being the case, they are to windward of the mast when the boat ia
on one tack, and to leeward when on the other.
In the case of a standing lug the tack is secured in a position close to
the mast by means of a tack lashing or small tackle. This may lead to
an eyebolt in the keelson close to the heel of the mast, or may be secured
to the mast itself. In some cases it is hooked to a strop fitted round
the mast. The yard is kept close to the mast by the traveller, which
is an iron ring round the mast and slides up and down when the yard
is hoisted and lowered.
When sailing wijh the wind well aft, a boom would spread the foot
of the sail out and thereby greatly increase its efficiency. This is
better than the common practice of holding the .clew out with a boat-
66
SHIPS* LIFE-BOATS
67
hook which may easily be let go and lost. If a boom is used the foot
only thlTTh f al ° Dg ifc> bUt ^ k b6St t0 have a clew Ashing
sad and anv * I ^ betWeen the 1)00111 and tte {oot thf
weather w ° r Spray ^ Was shl PP ed m the sail in bad
weather would immediately clear itself.
Boats of 25 feet or more in length also have a small jib This is
stemhead eanS ^ ^ sheefc ’ tbe tack bein 8 secured afc the
The most common form of sad used in ships’ life-boats is th* “A • •
lug,’’ as illustrated in Fig. 2. tbe dl PP m §
It is a free-footed sad, no boom being used. The only gear required
or it is the mast, yard (fitted with strop), traveller (with hoot) STde
p and down the mast, halyards, tack lashing and sheet. A hook is
x>ften used m preference to a lashing for securing the tack in its place
, f 3 f Ca ® da dlp P m S” lu 8 because, when turning to windward
the tac^has to be unhooked or got adrift, and together Jith the fore-end
of the yard dipped round the mast (shifted from one side to the other)
every time the boat is put about. otner)
• J? 6 ma f be ste PP ed “ boat so that the sheave hole is
fore-and-aft direction. This being done, the halyards will be equally
clear at the sheave hole whichever tank the boat is on. If the sheavl
hole was athwartehips, the halyards would be clear on one tack W
would he across the swallow of the sheave hole on the other tack. ’ihe
68 NICHOLLS’S SEAMANSHir AND NAUTICAL KNOWLEDGE
hauling part of the halyards would also be clear to lead fonvard , thereby
making a good forestay for the time being. The mast is generally
fitted with a pair of wire shrouds which are set up with lashings at the
gunwale.
One or two rows of reef points are usually put in the sail with corres¬
ponding reef cringles on the luff-rope for the tack, and on the after
leech for the sheet. These, of course, only come into use when the
sail is reefed.
SAILING A BOAT
With an Explanation of the Terms in General Use in Sailing Vessels.
When a vessel is sailing close to the wind she is said to be close-
hauled. If she has the wind abeam or abaft the beam she is said to be
“free.”
It is customary and proper in sailing vessels to steer from the weather
side; that is, the helmsman always stands at the weather side of the
tiller. A better view of the sails is obtained than is possible from the
lee side, and more of the horizon can be seen ahead.
In small vessels, when steering with a tiller, the order “up helm”
means that the tiller is to be moved towards the wind (to windward),
the rudder, of course, canting to leeward, and the vessel’s head paying off.
The term “down helm” means exactly the opposite to “up helm;”
that is, the tiller is to be moved away from the wind (to leeward), the
rudder is then canted to windward, and the vessel’s head comes up
towards the wind.
The order “ steady ” is used in all kinds of vessels, both under sail
and steam. It means that the vessel’s head is to be kept in that
particular direction in which it was at the instant of giving the order.
The helmsman should be told how much the course is to be altered
so that he may judge how much helm to give her, also when to ease
it so that she may not go beyond the desired direction. This also
applies when starboarding or porting the helm in a steamer.
When under sail the terms “up helm” and “down helm” are used
more than “port” or “starboard.”
' When the wind is right aft the order “up helm” or “down helm”
is understood according to which side of the wheel the man is steering
from.
When under examination or practising the Rule of the Road with
models it is best to use the terms “port” or “starboard” when the
wind is aft.
BOAT SAILjyr
69
Some square-rigged vessels will sail as near to the wind as 6 pomts
from it, but more often a vessel sailing close-hauled is heading between
6 and 7 points from the direction of the wind Yachts and other
fore-and-aft rigged vessels will sail closer to the wind than 6 points
from it, so also will ships’ boats when properly trimmed Many fore-
and-aft rigged vessels will sail 4 pomts from the wind with their
sails clean full.
When a vessel is sailing close-hauled she is said to be “ on a wind ”
or “ on the wind ” or “ steering by the wind. ” If she falls off through
careless steering she is said to be e£ off the wind.”
The term luff is used by seamen to indicate the act of bringing a
close-hauled ship up m the wind by easing the helm down, and thereby
causing the sails to shake This may be done to ease the pressure on
the sails and gear in a squall, or to take the wind out of a sail so that a
better puli can be got on a sheet or halyards, or for the purpose of
checking a ship’s way through the water without quite stopping her.
\Yhen the helm is put up again, and her head is canting away from
the wind she is said to be “paying off” or “filling,” and when the
sails are quite steady again she is said to be “full.* 5
When a vessel has the wind free, and it is required to bring her
nearer to the wind, the term “luff” is not generally used. The order
would be “let her come up a point,” “let her come to a point” or whatever
alteration of course was required.
Tacking is to bring the boat’s head to wind so as to change from close-
hauled on one tack to close-hauled on the other.
Wearing is keeping the boat’s head off the wind so as to change
from close-hauled on one tack to close-hauled on the other by bringing
the wind round the stem
Gybing is altering course so as to bring the wind round the stem
from one quarter to the other.
Whten sailing a ship’s boat with a fair wind, there is nothing to do
but steer for your objective and haul in or slacken o£E the sheet of the
sail should the wind alter in direction and always, in an open boat,
to be on the alert and ready to slack ofi the sheet quickly when a gust
or squall comes along. The sail is like a bag full of wind. The sheet
acts in the same way as a lashing on the mouth of a bag, you must let go the
lashing before the bag can be emptied. Similarly, let go the sheet to
empty or “spill” the wind out of the sail. It will flap and make a
noise because the pressure is off the canvas but the boat will retrain
upright. The particular danger when sailing an open boat in squally
70
NICflOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
weather is her lurching and dipping' the lee gunwale under water;
even if she is well ballasted she may not come upright as the lurching
tends to throw the weight of the crew to the lee side and their weight
heels her over still further. Never hesitate to slack off the sheet when
a puff of wind comes along, it is easily hauled in again.
The science of a boat beating to wmdward is an application of
simple mechanics. A boat with lugsail will make headway when 4
points, 45 degrees, from the wind, and she will zig-zag her way into the
wind’s eye tack f<sr tack; she will not make good the direction she is
heading as ship’s boats are flat-bottomed things and make a lot of
leeway.
In the figure the arrow and dotted line represent a North wind
blowing down the page. A is a boat close-hauled
VVI i N0 on the port tack heading N.E. She tacks at B and
i heads N.W. towards G on the starboard tack. She
tacks at C and heads N.E. for D ®n the port tack.
She changes again from port to starboard tack at D
and heads N.W. for E. The distance made good to
‘windward is from A to E. If AB*i& one mile, BG
2 miles, CD 2 miles and DE 1 mile the boat sails
6 miles in all. It will be found on looking up the
Traverse Table with 45° as a course and these dist¬
ances in the Distance column that the Difference of
Latitude column gives 4*2 miles which is the length
of AE, so that the boat has sailed 6 miles to make
good 4*2 miles against the wind. She would actually
have to do more as there is always some leeway to
make up.
The trim' of a , boat is a vital factor in
determining her sailing qualities. When a boat is
down by the head she will try to bring herself head
pig 3 _Tacking to w ^ n( ^ an< ^ w hen down by the stern she wants to
to Wmdwaxd put her stem into the wind. The deep or heavy end
of the boat tends to hang to windward; this, of
course, may be counteracted with the rudder but the angled rudder
would retard the boat’s speed. Immediately on getting under wa)
the position of the members of the crew should be changed about
until the best sailing balance or trim of the boat is found. The person
steering can tell this by* the feel of the tiller because when the boat ia
in nice trim she requires very little helm.
BOAT SAILS
71
The knack of sailing a boat can only be acquired from experience and
no opportunity should be withheld from, or rejected by, responsible
members of a ship’s crew of gettmg practice whenever possible.
The crew of the ss Trevessa got two hours 5 notice to prepare for a
trip of 1700 miles in open boats ^when their ship suddenly and myster¬
iously foundered in the middle of the Indian Ocean in 1923. It was
fortunate for the crew that the captain and the chief officer had
previous experience in handling a boat under sail.
BOAT SAILS.
1. What materials are boat sails made of?
The cloth should be of best quality duck. The sail should be
litted with reef points sewn into the bottom of the holes, reef cringles
should also be worked on the luff rope and leech.
The roping should be of good quality manila or boltrope sewn on
with roping twine.
Galvanised iron or gunmetal thimbles are used at the throat, peak,
tack, and clew, also in the reef cringles.
2. Describe how a boat’s sails should be trimmed when she is under
way.
When the wind is right aft the sheet should be eased off far enough
# to allow the sail to be practically at right angles to the keel of the boat.
As the wind hauls out on the side, or as the course is altered bringing
the wind out on the side, the sheet should be hauled in a little to enable
the sail to draw properly and to take full advantage of the breeze
then blowing. If the boat carries a jib it should be set, the sheet being
eased well off.
As the wind hauls further out on the side, both the main and jib
sheets should be taken in a little more, until, when the boat is on the
wind (close-hauled), the sheets are flat aft.
As the wind frees again, the sheets must be correspondingly eased
off.
Never, under any conditions, should the sheet be made fast in an .
open boat. It should he taken round a cleat, belaying pin, or thwart,
and held in the hand.
When the boat is upright, properly ballasted, and the sails well
trimmed she should carry the helm nearly amidships, but when she
Has the wind on the side and is laying over she will require a little
weather helm to keep her going straight.
72
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
BOAT SAILING
3. What would you do in a squall with the wind well free, also when
close-hauled' 2
Having the wind well free, I should put the helm up a little and keep
hex away before the squall struck me I might ease the sheet off as the
squall came along, and if it was very stiff lower the yard down. The
jib would then keep her going. If no jib, I should leave her a little bit
of the lugsail instead.
I should also look out for a possible shift of wind in the squall,
and see that I was not caught by the lee.
When close-hauled I should mind my helm very carefully, and luff
her through it easing the sheets off at the same time.
When the squall was over, I should keep her away far enough to
fill the sails, and haul the sheets aft again.
If she came up too far when I luffed, or if the wind shifted and I got
it on the other side, should shift my sheets across and put her on the
other tack, keeping my luff if possible until the squall was over.
“ Caught by the lee 99 means getting the wind on the wrong side of the
sail, thereby causing it to come right across to the other side of the boat.
This may be caused by a shift of wind as before mentioned, ox by
careless steering.
“ Luff her through it 99 means keeping her up with the sail shaking
in the wind so that the pressure is taken out of it until the squall is over,
4. Does an ordinary ship’s life-boat generally do well under sail?
If properly trimmed she should sail fairly well with the wind abaft
the beam, but except in smooth water and fine weather would not be
much good for getting to windward.
5. What could be done to improve her sailing qualities when on a
wind?
*
Fit an iron keel. An iron or steel plate fitted to the wooden keel
of the boat for about one-third to one-half of her length amidships and
bolted right through would answer the purpose very well.
This should be anything up to 9 inches or 1 foot deep, and tapered
with a fair curve at both ends. It should be easily detachable.
Needless to say, a boat so fitted would not be suitable for running
up on to a hard beach.
6. How would you set a dipping lug?
Lay the yard and sail fore and aft on that side of the mast whicn
BOAT SAILING
73
will be the lee side when under way. Hook the tack on in its place,
and the hook of the traveller on to the strop on the yard, passing th/»
sheet aft.
Hoist the yard and sweat the luff rope up tight, topping the yard
up to the proper angle.
The sheet should be led through a strop placed aft in a suitable
position, or round a cleat or belaying pin, or under a thwart, and held
in the hand.
On no account should it be made fast.
If the boat is going away with the wind well free I should take the
tack down (or hook it) on the weather side at a distance abaft the stem
which will depend on the size of the boat, the position in which the
mast is stepped, and the way in which the boat is going to carry the
wind.
If only a hook is fitted in a certain position, of course, there is no
alternative but to hook it there.
If going away close-hauled the tack should be secured to the stem
head or thereabouts
7. How would you “ go about ” in a boat fitted with a dipping lug?
Keep her clean lull for a moment until she gathers good way, and
then ease the helm down. When the sail shakes, settle the yard down
a bit, unhook the tack, and taking hold of the lufi rope with both hands
pull down and aft on it, dipping the yard round on to the other side of*
the mast. Let go the luff rope, hook the tack on again and sweat the
luff up tight by means of the halyards. Pass the sheet to leeward,
steady the helm.
With a weak or unskilful crew or in bad weather it may be better to
lower the yard right down when going about instead of only settling
it down a few feet. It will take longer, and the boat will lose moie way,
and go a little to leeward at the same time. It is however safer, and
provides less chances for an accident.
To do it this way, ease the helm down and when the sail shakes
lower the yard and sail right down on to the thwarts. ' Unhook the
tack, also the strop on the yard from the traveller, and shift the yard
and sail across on to the other side of the mast. Hook the tack and
traveller on again, hoist away and sweat the luff rope up tight, trim the
sheet, mind the helm.
8. How would you set a standing lug?
The procedure is the same as for a dipping lug except in the manner
74
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
of arranging the tack. This is secured in a position close to the mast
instead of being hooked on to the weather bow or stemhead. Secme
the tack, hook the strop on the yard on to the traveller, and pass the
sheet aft. Sweat up on the halyards until the luff rope is well tight
and the yard topped up into the correct position. Hold the sheet in
the hand.
If the sail is fitted with a small tack tackle or lashing, it is much
better and more seamanlike to hoist the yard up to the required height
-first and bowse the tack down afterwards.
9. How would you go about with a standing lug?
Get good way on the boat, and ease the helm down. As she comes
up in the wind the sail will shake, and if there is not too much sea she
will come round head to wind and pay off on the other tack. As she
falls off, the sheet having been passed to leeward, I should tend it,
steady the helm, and shift my position across to the weather t side.
When going about under a standing lugsail if the boat is not carrying
a jib, the only things to be dealt with are the helm and the sheet.
If a jib is set, the sheet must be eased off at the same time that the
helm is put down, and the other one hauled aft as she fills on the other
. tack.
10. What would you do if, when you put the helm down, she came
up into the wind and then stopped, refusing to come right round?
Get an oar out and pull her round. The steering oar would be the
handiest, but the bow oar would also answer the purpose. The latter
would have to be'used on that side which was the lee side before putting
the helm down.
If the boat Had a jib set, hauling the clew to windward would also
help in “boxing her off.”
11. Wind aft. How / would you put a reef in a lugsail?
The method is the same for both “standing” and “dipping” lugs.
Lower the yard and sail right down, reeve the tack and sheet
through their proper reef cringles. This will leave the foot
of the sail free. Gather it up snugly, and tie the reef points tightly
round it. Set the sail again in the same way as if there was no reef in it.
12. Which rig do you prefer, the “dipping lug” or the “standing lug?”
Give your reason.
ffor sailing with the wind aft or well free, I prefer the dipping lug.
The sail spreads better than the standing one by reason of its tack
BOAT SAILING
75
being taken out to the weather gunwale, and consequently under those
conditions it is the more efficient sail of the two. When the wind is
aft, the side opposite to that on which the sheet is earned may be
considered the weather side
For turning to windward I prefer the standing lug. It has an advant¬
age over the dipping lug every time the boat goes about as the yard
remains at the masthead all the time, no dipping of the yard and sail
being required. For this reason, time and leeway are saved specially
when beating m narrow waters where frequent tacking is necessary.
Under a standing lug a boat should go from one tack to the other without
losing her way, and would consequently be more weatherly than if
fitted with a dipping lug.
These remarks apply to the conditions under which a ship’s boat is
likely to be sailed, when she might be manned largely by firemen, cooks,
or stewards. Wxih an expert crew the difference is not so marked.
13. Are the yard and sail always to leeward of the mast when a boat is
under way?
No. With a standing lug the yard and sail are to windward of the
mast on one tack, and to leeward on the other.
With a dipping lug they are always carried to leeward, being dipped
round the mast each xtime the boat goes about.
14. Are life-boats required to carry a jib in addition to their lugsail?
Life-boats of 25 feet m length or more are required to carry
a jib. The carrying of a jib by smaller boats is not compulsory.
15. What use can be made of a jib when the wind is aft, also when
“going about”?
When the wind is aft, the clew of the jib may be boomed out on
the opposite side to the lugsail, thereby giving a larger effective sail
area and more way to the boat. It is not necessary in a strong breeze,
but makes all the difference when the wind is light.
The jib halyards being well set up, the luff rope makes a good
forestay. This may be very useful when the boat is diving into a
head sea.
When going about, the jib sheet is eased off at the same instant that
the helm is put down. If the boat is “slack in stays” and hangs up in
the wind, hauling the jib sheet to windward will help her to pay off on
the other tack
76
NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
16. Describe what is meant by the term “gybing,” and how it is done ?
When a boat is sailing with the wind a little on the quarter, it may
be necessary to put the helm up a little and bring the wind round the
stern on to the other quarter. This manoeuvre is termed “gybing.”
It should only be done in light winds and fine weather.
With a standing lug, the sheet and clew of the sail are hauled gently
and carefully aft as the helm is put up, and are allowed to fall away
on the other side of the boat as the wind comes round on to the other
quarter. The wind will now be on the other side of the sail.
A shift of wind round the stern would make it necessary to “gybe;”
this shift of wind would always be carefully looked out for.
When sailing with the wind right aft, and by hauling the sheet
aft, the wind is brought on to the other side of the sail, the sail at the same
time going across to the other side of the boat , she is said to be gybed
Note that in this case the boat’s course has not been altered.
Do not attempt to gybe if there is much wind or if you have an
unskilful crew or a boat-load of passengers. Lower the sail right
down, and pass it across to the other side of the boat before hoisting
it up again.
With a “dipping” lug the yard and sail must be lowered right down,
and dipped round the mast m all cases. The tack and traveller will
have to be unhooked to do this, and, of course, hooked" on again before
re-hoisting.
17. What particular precautions should be taken when sailing with
the wind right aft?
The main thing to guard against is an “accidental gybe.” This
may be caused by allowing the boat to be caught by the lee through
careless steering or by a sudden shift o‘f wind. Such being the case,
the sail will come right across with little warning. With a free-footed
sail as used in ships 5 boats, this may mean nothing more than caps going
over the side, but when a boom comes across it might be more disastrous.
In a strong breeze, the sail or even the mast might be carried away,
at the same time the boat is likely to “broach to.” '
The precautions to take would be to watch the steering very care¬
fully, keep a sharp look-out for any signs of a shift of wind, and take
care that she is not “caught by the lee.” Should that happen, ease the
sheet right off, and meet her with the helm to stop her broaching to.
BOAT SAILING
77
18. Your ship is anchored in an open roadstead where there is no tide.
Your port boat is alongside. Describe how you would get her
under way and sail into the harbour, the entrance being on your
port beam, distant 2 miles.
As there is no tide, both ship and boat will be lying head to wind.
Have the yard and sail on the port side of the boat, step the mast and
clamp it. Set the sail, when it will simply shake in the wind, the
sheet being quite free.
When ready let go the boatrope (should not use the boat’s painter
as that involves the necessity of hauling it in) and shove her bow off.
As she falls off, the sail will fill. Tend the sheet and the helm.
I should keep her heading well to windward of the entrance to allow
for leeway. That is, I should go away on the starboard tack sailing
her “full and by” when she ought to fetch in.
If on account of leeway, I found that she would not make the entrance *
on the starboard tack, I should down sail and mast and pull for it. It
would not be any use going round on to the other tack, as she would
continue to make leeway, thereby getting further from her destination.
As soon as I saw that she would not fetch in I should not hesitate to get
the oars out. The longer I delayed, the further I should have to pull.
19. What would you do when sailing a boat if a man fell overboard?
Throw him a life-buoy or something that will float, taking care
not to hit him with it. Down helm and shoot the boat’s head up into
the wind; lower the sail as quickly as possible, out oars and pull hard
towards the man. The boat will be to windward of the man and, when
approaching him, have hands leaning over each bow ready to get hold
of him. When close to the man I would order “way enough,” then
“hold water” with the oars so that the boat may not run the man
down.
Ships’ boats are not built or rigged for handiness in manoeuvring
under sail, but should a man fall overboard from a weathexly sailing
yacht the quickest way of getting to him is to gybe and then tack
towards him.
20. Wind aft, man overboard, what would you do?
I would throw him a life-buoy or any loose article that might support
him. Down helm, lower the sail and pull hard towards him. The
boat will be only a short distance to leeward of the man and the boat
will reach him quicker under oars than by manoeuvring under sail.
78
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
21. Would you act differently if you were in a tideway when a man
fell overboard?
No. The tide affecting both man and boat in practically the same
way, my action would be the same.
22. In what practical way could you help him to get back on board?
A couple of hands could help him in over the gunwale, or over the
stem if I was afraid of putting her gunwale under.
A strop made with the end of the sheet or painter, hung over
the rudder head or a crutch, could be used as a stirrup. This would be
specially useful if I had no crew on board to otherwise help him.
23. The wind blowing right on to the land, how would you get a boat
landed on a beach where there is a nasty surf?
I should take precautions to prevent her broaching to as I got into
the surf.
If it was a gradually shelving beach there would be more broken
water to go through than there would be if it was steeper. Broaching
to is caused by a sea catching her aft or on the quarter, or by an oncoming
sea lifting the stern and depressing the bow and thus turning her round.
I should remember this when deciding where to stow any weighty
objects I had on board, distributed amidships would be the best place,
also when considering the positions to be taken up by my crew and
passengers.
In an ordinary ship’s life-boat I should keep good way on her and
run her straight up, lowering the sail and gathering it in if possible just
before she touched. If no signals on shore to guide me I should carefully
pick out what appeared to be the best position for that purpose. If
there was plenty of assistance on the beach she could be quickly hauled
up; if not, all hands would have to jump out as soon as she touched and
haul her up themselves.
If the boat had a square stem I should turn her round bow on to
the sea and back her in with the oars, having lowered my sail and
unstepped my mast if practicable before getting into the surf. As each
sea came on I should give her a little headway against it to prevent her
being swung round by it.
A Bea anchor, grapnel, or heavy weight could be veered out on the
end of a line before approaching the beach. This would act as a“ drogue,
and be of considerable assistance in preventing her getting broadside
BOAT SAILING
79
on before landing A small anchor let go in a weatherly position
would answer the same purpose
Oil distributed from a bag made fast to the sea anchor or to the
iine being veered out to the ground anchor might be of some service,
though nothing will prevent the waves from breaking when water
becomes shallow.
24. What signals are used on the home coasts to assist you in choosing
a place to land ?
A flag held upright overhead, or a white flare held steady or stuck
in the ground, indicates a place where I might attempt to land.
A flag or white flare waved from side to side indicates that landing is
extremely dangerous.
A flag waved to right or left and then pointed in one direction, or a
white flare held steady and earned along shore to right or left, indicate N
the direction in which the best landing will be found.
25. What precautions would be necessary for safety if you were carrying
a boat-load of passengers?
I should be careful to see that the boat wa*s properly trimmed and
not overloaded.
Should make a number of my passengers sit or lie down in the bottom
of the boat, the remainder sitting on the side benches and thwarts in
positions which I should choose for them, having consideration for the
working of the sails and manning of the oars if necessary. If the wind
was on the side should want more of them to windward than to leeward.
In the event of having to go about should instruct some of them as
to moving across to windward at my orders as she came round.
Should see that all had their life-jackets on, and remind them that
their safety depended on the prompt obeying of any orders I might
issue to them.
Should realise my own responsibility, remembering that should
any awkward conditions arise the safety of all would depend on my
judgment'and action.
26. Where do you make the lugsail halyards fast?
Forward of the mast on the weather side. They will then help to
support the mast, acting as stay and shroud.
27. How would you bend a lugsail to the yard?
Pass a good throat and peak lashing, having the head of the sail
well stretched along the yard. Pass good stops through each eyelet
80
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
hole and make them fast round the yard. Separate stops are preferable
to a lacing as if any part of the lacing carried away the whole head
of the sail would be adrift except the throat and peak lashings.
28. How much of a life-boat sail is roped?
The head, luff, and round the tack. Also round the clew and up
the after leech as far as the reef cringles. The remainder of the* foot
and after leech are generally strengthened only by the tabling.
29. How would you reef a lugsail when on the wind?
Luff the boat up sufficiently to spill the wind out of the sail. Lower
the yard down and gather the sail into the boat. Shift the tack and
sheet to the reef cringles. Gather up the slack of the foot neatly and
tie the reef points round it. 'Do not roll up the foot as it holds more
water when done that way. Hook the tack on to the horse, pass the
sheet aft. Hoist the yard up again, tend to the sheet and helm.
30. How would you heave to m a life-boat when running before a
strong breeze?
Ease off the sheet a bit to take some of the weight out of the sail.
Lower the yard down and gather the sail into the boat. Keep her
steady by means of the steering oar. Watch for a smooth, round her
to and heave the sea anchor over. Make everything snug in the boat.
SAILING BOAT RULE OF THE ROAD
Preliminary—Risk of Collision.
“Risk of collision can, when circumstances permit, be ascertained by
carefully watching the compass bearing of an approaching vessel. If
the bearing does not appreciably change, such risk should be deemed
to exist.”
“Art. 17. —When two sailing vessels are approaching one another,
so as to involve risk of collision, one of them shall keep out of the way
of the other, as follows, viz.:—
(a) A vessel which is running free shall keep out of the way of a
vessel which is close-hauled.
lb) A vessel which is close-hauled on the port tack shall keep out
of the way of a vessel which is close-hauled on the starboard
tack.
(c) When both are running free, with the wind on different sides,
the vessel which has the wind on the port side shall keep out of
the way of the other.
RULE OF THE ROAD 81
(d) When both are running free, with the wind on the same side,
the vessel which is to windward shall keep out of the way of
the vessel which is to leeward.
(e) A vessel which has the wind aft shall keep out of the way of
the other vessel.
Fig 4.—Rule of the Road.
Suppose you are practising boat sailing in a harbour with several
other sailing craft tacking, gybing and manoeuvring about, crossing
and re-crossing ahead of each other, and let us imagine ourselves to take
a trick at the tiller of each of the five boats in turn as shown in
Figure 4. The boats are proceeding in the direction they are heading,
the wind is West blowing across the page from left to right as indicated
82 V<CHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
by the arrows and the pennants at masthead or gaffend. The yachts
are sloop rigged (mainsail and one jib), except No. 3, which is a yawl
ng as the jigger mast is abaft the tiller; when the jigger mast is forward
of the tiller the vessel is ketch rigged.
Boat No. 1 is close-hauled on port tack.
No 2 is close-hauled on starboard tack.
No. 3 is running free with the wind on her starboard quarter
No. 4 has the wind right aft.
No. 5 is running free with the wind on her port quarter.
Refer to the diagram and state what you would do for each of tht>
other four boats in the following cases if meeting them so as to involve
Tisk of collision. Consider one boat at a time and cover with your hand
the other three boats.
What would you do if (a) in Boat No. 1, (b) in No. 2, (c) in No. 3,
(d) in No. 4, (e) in No. 5 ?
(crt No. 1 is close-hauled to port. Keep clear of No. 2 as she is
close-hauled to starboard* Stand on for Nos. 3, 4 and 5 as they are all
running free with the wind well abaft the beam.
( b ) No. 2 is close-hauled to starboard. Stand on for all four boats.
For Nos 3, 4 and 5 because they are free and for No. 1 because she is
close hauled to port.
(c) No. 3 is free with the wind on starboard quarter. Keep clear
of Nos. 1 and 2 because they are close-hauled. Stand on for No. 4
and No. 5. For No. 4 because she has the wind aft and for No. 5 because
she is free with the wind on her port quarter.
(d) No. 4 has the wind nght aft. She keeps clear of all the other
boats.
(e) Nos. 5 has the wind on the port quarter. Keep clear of No. 1
and 2 because they are close-hauled. t Keep clear of No. 3 she is free to
starboard. Stand on for No. 4 as she has the wind right aft. If No. 4
had the wind on her port quarter as might be indicated by her main
boom being out to starboard I would still stand on as she would then be
lie weather ship, that is, she has the wind on the same side as me and
to windwaid of me. *
CHAPTER VI,
SECTION I.—SHIP’S BOAT*
Boat Lowering
The launching of a boat from a small ship at sea in moderate weather
is an easy operation as the crew, being few m number, are usually
experienced seamen, well trained and accustomed to team work. North
Sea fisherman often remain at sea for a considerable time, and they
convey m an open boat in all kinds of weather the boxes of fish to the
fast steam earners who run the fish to market And were it not that
this is the ordinary work-a-day business of these hardy and experienced
boatmen, the operation in stormy weather would be hailed as a feat of
practical seamanship.
In large cargo steamships the launching of a life-boat is a more
difficult job owing to the height of the boat deck above the waterlme.
Cargo ships are equipped with life-boat accommodation under davits on
each side of the ship sufficient to carry all hands. Bigger boats are
therefore needed and these require heavier davit tackles, the awkward¬
ness of launching the boats being further increased by the inexperience
of the crew who are seldom or ever exercised in real boatwork at sea,
their only practice being an occasional boat station and the lowering
of boats for inspection purposes in harbour.
The problem of “carrying a sufficiency of buoyant life-saving appli¬
ances in ocean passenger liners to accommodate all hands is complicated,
not so much by the large complement of passengers and crew they may
carry, but mainly by the difficulty of providing stowage space to provide
boats for all and devising mechanical launching arrangements to get
the boats lowered down the ship’s side, a distance sometimes of 50 to 70
feet, and to get them clear of the ship’s side in the event of a sudden
emergency call.
Legislation regarding life-boat and buoyancy equipment was
introduced after the loss of the Titanic in April, 1912. This 52,000-ton
liner foundered after collision with an iceberg in mid-Atlantic in calm
but hazy weather. The ship was not at first expected to founder and
83
84 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
all her boats were launched leisurely and deliberately, filled with their
full complement of people and ordered to stand by around the ship.
The ship, however, settled down slowly and eventually sank, 2| hours
after striking the berg, taking with her 1531 souls who stood helpless on
deck as there were no more boats or rafts left for them to embark upon.
Wireless telegraphy was not then compulsory nor was a continuous
wireless watch kept at that time, and the crowning tragedy of th$
Titanic was the presence only 8 or 10 miles away of a wireless equipped
ship whose operator was off duty while the S O.S. of the sinking
liner was searching the ocean for aid which arrived four hours after she
foundered.
Large liners are now equipped with a multiplicity of life-boats
and buoyant apparatus having a floatable capacity capable of supporting
the total number of persons on their passenger certificate plus 25 per
cent.
DAVITS.
The most expert and ingenious of naval architects and engineers
have applied their brains to the problem of providing simple and reason-
.Fig. 1,—Radial Davits, a Liner’s Boat Deck.
Note tackle and springs on the funnel guys to allow for expansion.
BOAT LOWEKLNG
85
ably fool-proof launching apparatus of a mechanical type which would
be effective in an emergency with the ship in a seaway and listed to a
considerable angle.
Modern davits ^re of three types designed on the radial, the quadrant
and the gravity principles, as shown in the various illustrations.
The Two Davit Radial Type is a survival of sailing ship days when
only man-power and rope tackles were available at sea. They are
still being fitted in steamships, but the system has little to commend it
as it is cumbersome, slow and awkward to work, especially when the
boats are housed inboard.
The Welin Quadrant Davit is well known, and is specially adapted for
handling one boat, or two boats stowed either abreast or over each
other, or for nested boats, the davit being designed for the rapid and
effective lowering of the life-boats in an emergency by persons who
may have had but little practice in the operation.
Fig. 2.—Welin-Maclachan Gravity Davits. Boats in stowed position.
The Welin-Maclachian Gravity Davit enables one man to lower a
life-boat of any size, and fully laden, from its stowed position on the
ship down to the water by* the simple process of operating a hand
lever. The boat is stowed on cradles mounted on rollers which move
over parallel trackways laid at right angles to the ship's side and
carried down to the embarkation deck. The trackway or launching
Conti ol Lever
86 NIGHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
skids extending inboard over the deck are given a declivity of 30
degrees', so the boat can be launched against a list up to this angle.
Fig. 3.—Boat at Embarkation Deck.
► * L' -
The falls are of single wire rope led to, and stowed on, a simple
hand winch which operates both falls simultaneously.
-When launching, the brake lever of the winch is lifted, and the
cradles and boat move together under their own weight until the cradles
BOAT LOWERING
87
reach the stoppers. The cradles remain at rest on the stoppers and the
boat comes automatically alongside the embarkation deck, irrespective
of list. When the life-boat has its full complement on board, the brake
lever is again lifted and the boat continues to the water. The hoisting
of the boats is effected by means of the winch, and in the case of the
larger class of boats electric hoisting power winches are supplied for
lifting the boats up the ship’s side to the stowed position In tests
carried out under inspection of Board of Trade officers, the time occupied
from the releasing of the gripes until the boats reached the water (a
distance of 40 feet) varied between 20 and 28 seconds, the whole
operation being carried out by one man.
1. You are m charge of a boat’s crew of 10 men undergoing a Board
of Trade examination for a certificate as lifeboatman; how would
you place them, and what orders in succession would you give
to carry out the operation of swinging out the boat, lowering it,
and getting away clear of the ship’s side, with radial davits?
Hang the side ladder over at the boat station.
Crew line up and number off from forward, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.
Nos. 1 and 10 into the boat. No. 1 pass out the forward fall and
see life-lines clear. No. 10 pass out the after fall and see the bottom
plug is in. Nos. 2 and 3 pass the end of the slip painter into the boat.
Nos. 4 and 5 attend to the forward fall.
Nos. 6 and 7 let go the gripes.
Nos. 8 and 9 attend to the after fall.
Nos. 2, 3, 4 and 5 tail on to the forward fall.
Nos. 6, 7, 8 and 9 tail on to the after fall.
Take the weight of the boat and down chocks Nos. 2 and 3 to the
forward guy and Nos. 6 and 7 to the after guy.
Slack away guys and swing the boat out, then steady tight the
guys and lower the boat to the rail. No. 10 ship the rudder. Crew into
the boat, leaving Nos. 4 and 5, 8 and 9 at their falls. Lower away.
Fend the boat off from the ship’s side as she goes down. When the
boat touches the water, let go both falls together. Nos. 4, 5, 8 and 9
slide down the falls, or the life-lines, or go down the ladder into the boat.
Follow them myself.
When the crew are in their places in the boat give the order “Crew—
ship rowlocks and oars ready.” No. 1 slip the painter and push off
forward with the boathook. No. 10 at the tiller. “Crew—out oars.'’
Push off from the ship’s side. Give way.
88
NICHOLES* S SEAMANSHIP AND NUTTICAL KNOWLEDGE
2. How would you launch, a life-boat with the Welm Quadrant Davit
fitted with tackle falls and given 6 hands?
Humber off the crew 1, 2, 3, 4, 5, 6.
Nos. 1 and 2 into the boat, pass out the davit falls, bottom plug in
and see life-lines clear.
No. 3 pass the end of the slip painter into the boat. No. 4 let go
gripes and down chocks, then Nos. 3 and 4 man the turning gear at each
davit and turn the boat out.
' Fig 4.—Weiin Quadrant Davit.
Nos. 5 and 6, one to each davit fall and lower away to the embark¬
ation deck. Nos. 3 and 4 backing up the falls.
When everybody is embarked, lower away to the water, let*go the
falls and unhook the blocks. The four hands on deck slide down the
life-lines or davit falls into the boat.-
Ckew—out oars, let go the slip painter, push off, give way together.
3. Describe how you would launch a boat with the Welin-Maclaehlan
Gravity Davit and three hands?
Two hands into the boat and see life-lines clear and bottom plug in.
One hand casts off the gripes, then goes to the winch brake and raises
lever. The boat automatically slides down .the runway and finds its
BOAT LOWERING
89
way to the embarkation deck. The end of the slip painter- is then,
passed into the boat, and when the people are embarked the winchman
lowers the boat to the water.
4, Your ship is fitted with the ordinary radial davits, describe how
you would get a boat out at sea .
Take the cover off, remove the fore-and ^af ter, also the spreaders.
90
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
fc5ee that all the gear is in order, and that there is nothing in the
boat which is not required.
Pass a boatrope along from forward outside the davits, reeve it
through the ring in the bow and make it fast round the forward thwart;
this is better than using the painter which would have to be hauled into
the boat when getting away.
Put the plug in.
Come up the gripes, take the weight of the boat, attend to the outside
parts of the chocks.
Let go the guys, haul the boat aft a little and push her bow out, then
hauling her forward a little, push the stern out.
Ship the rudder.
Steady the davits in their proper position by means of their guys
and span.
Lower the boat down to that position where it is best and easiest
for the crew and passengers (if any) to get in. The boat being manned,
lower, her down into the water and let go both tackles at the same time
Have the oars or sail all ready. Cast the boatrope adrift, shove off.
I should remember that a moderate breeze on board a ship is a gale
of wind in a small boat, and if T thought it necessary should see that all
persons had their life-jackets on.
5. How would you take her back on board again?
Give her a boatrope as she came alongside, and bring her under the
davits. Leave two men in the boat, and let all the others come on
board the ship.
Overhaul the tackles down, hook the forward one on first and take
up the slack, then hook the after one on, and when ready hoist away
on both. If the ship were at sea and rolling or if the boat were lively
in a seaway, both tackles should be hooked on at the same time and the
hands on deck prepared to run in the slack of the falls quickly.
When the boat is clear of the water, take the plug out to drain her
out, also unship the rudder.
When high enough, belay the falls, let go the guys, and swing her
inboard.
Lower carefully down on te the chocks, secure the gripes
Clean her out if necessary, see that all her equipment is in good
ortler and that nothing is missing.
Cover her over.
BOAT LOWERING
91
6 Your ship is at sea. How would you get away trom her and set
sail in a boat?
Stop the ship. Clear away the lee boat and lower her down as
described in “boat lowering, etc. 55 Pass the boatrope aft along the
inboard side of the boat, and when you are all ready sheer clear of the
ship and let go. Out oars and pull away. Step the mast and set the
sail.
If the ship was steady I should step the mast and hoist the sail
before sheering away clear of her.
7. Your ship is rolling heavily How would you launch a lifeboat?
Stop the ship. At the time of lowering have the ship headmg
up in that direction m which she will lie the steadiest. Clear the
lee boat away and have the boatrope ready as in fine weather. Get
the crew in and lower her down to the level of the deck. Keep her well
frapped in and held by the gunwale until a favourable opportunity
comes for launching. Have oil ready for spreading if required. When
the ship rolls the right way let go trappings, lower away quickly and
unhook the falls. Pass the t*>atrope aft along the inboard side of the
ooat and give her v a sheer off. Out oars and get a safe distance from
the ship. Step the mast and set sail.
8 What are the length and size of the davit tackle falls?
They must be long enough to lower the boat safely into the water
when the ship is floating at her lightest draught.
The size should be 3£ to 3f inches for boats not exceeding 27 feet
in length, and 4 to 4£ inches for boats between 27 and 30 feet in length.
9. How would you fit new davit tackle falls?
Open up a coil of new rope and thoroughfoot it well. If the ship
is “flying light, 5 ’ reeve off the fall and overhaul the tackle until the lower
block nearly touches the water, cut the rope at a suitable length.
If the ship is loaded the easiest way to get the right length is by
comparison with the old falls.
Should no odd falls be available, find the height of the upper blocks
above the light waterline. This will give the length (very liberanv;
of one part of the fall. The tackles being three-fold purcnases. *tx
times this length, plus a few feet for the inboard end, wifi be the length
of the fall.
92
NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
10 Is it required that boats shall he fitted with any mechanical gear
for disengaging the falls ?
No It is not necessary when proper means are provided for
detaching each fall by hand.
Mechanical disengaging gears may be fitted, but must be of a design
approved by the Board of Trade. They must be so arranged as to
ensure simultaneous release of both ends of the boat, and must comply
with various other conditions. The hooks must also be suitable for
instant unhooking by hand.
THE MOTOR LAUNCH,
The paraffin fuel tank is usually fitted in the bows of the boat
under the forward deck. A small half gallon tank to hold the petrol
for starting up the engine is fitted m a convenient place. Both fuel
tanks are placed a little higher than the level of the cylinders so as to
get a gravity feed to the engine. The petrol and paraffin can be tinned
on and off as required by means of a two-way cock at the engine.
Before Starting Up, the running parts in contact should be lubricated
by dropping oil in the several oil holes. The bearings along the pro¬
peller shafting should be well oiled and the clutch working freely.
The sea cocks of the cooling water system must be opened!
. To Start U P> turn on the petrol feed, slack back the compression
taps on the top of the cylinders, squirt a little petrol into each one,
then tighten the taps up again. See the clutch is out. Turn the
starting handle with a vigorous throw-over and this will start the engine.
Allow the engine to run for a few minutes to warm up the several parts, -
make sure the circulating water for cooling the engine is all clear by
looking at the overside exhaust. Accelerate and decelerate the engine
to see that it is running all right.
. To Get Dnder Way.—Assuming the engine is now running slowly
in neutral gear I would see there, were no loose ends of cordage hanging
over the side to foul the propeller. Cast off mooring and go ahead
steering the boat as required. Switch over from petrol to paraffin.
1. Why is it necessary to start the engine on petrol?
Because paraffin will not remain in vapour form when miV.rl ^th -
coid air. The vaporiser on the engine could be heated by means of a
bow-lamp until the temperature of the vapour is raised to about 140°
Fahrenheit- when the mixture will explode. This process, however,
THE MOTOR LATTXCH
is slow and a nuisance. Petrol fuel vaporises at ordinary temperatures,
and when the petrol and air enter the cylinders in proper proportions
an explosive mixture is at once formed.
STARBOARD SIDE
Fig. 6.—Kelvin Marine Motor for Ship’s life-boat.
Precautions .—To ensure the effective running of the engine it is
desirable that the pipes leading from the fuel tanks be fitted with a
fine wire gauze diaphragm to act as a strainer to keep back any sediment
9i NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
that may he in the paraffin. The fuel enters the carburetter through *
very minute jet and is mixed with a regulated intake oi air to torm an
explosive mixture before entering the cylinder.
The inlet and outlet pipes of the water cooling system should also
be fitted with strainers to prevent scum, weed and dirt coming in
from the sea. These strainers should be cleaned occasionally. All
parts should be kept as dry as possible especially the electrical equipment,
the wiring of which is insulated. The engine and boat must be kept
clean and no waste oil should be left in the bilge or in the drip tray
under the engine. A hand fire extinguisher and a bucket of sand are
kept handy to smother out quickly anything that may get ignited.
2. What is a magneto?
A magneto is a small dynamo which generates the current of elec¬
tricity to provide the ignition necessary to explode the mixture in the
cylinders. The current passes along the insulated wire leading from
the magneto to the sparking plugs screwed into the tops of the cylinders.
The distance between the terminals of the plug is called the spark gap,
and the make and break contact at the magneto is so timed that ignition
of the compressed vapour in the cylinders takes place at the correct
moment and the explosion drives the piston. The terminals of sparking
plugs get sooted up-so they have to be unscrewed and wiped clean
occasionally.
3. You are in charge of a motor launch, describe the procedure of
manoeuvring her alongside the accommodation ladder on the
starboard side of ship at anchor head to wind and tide. You
are approaching the ship on her port side.
I would shape a course that would counteract the effect of the tide.
This is done by watching the bearing of a stationary object and noting
whether the bearing draws ahead, astern or remains the same. If the
relative bearing does not alter the boat is making her course. I would
pass under the stem of the ship, not too close, and head up for a position
a little outside the ladder, slow down the engine by closing the throttle
a little, keeping enough way on the launch to overrun the tide. When
abreast of the ladder I would sheer alongside gently and get hold of the
boatrope, then put the engine into neutral.
4- -a man falls overboard from she launch, what action would you thke
to. pick him up quickly?
Throw him a life-buoy, engine full astern and steer towards Him.
RULE OF THE ROAD
95
Most motor launches can be steered with sternway on them. They
are unlike a big steamer in this respect as the rudder of a small boat has
a greater turning effect than the ^opeller The stern of a big ship
invariably turns to port when going astern against the action of the
rudder when put hard over.
5. Running down stream with a strong ebb tide, describe how you
would bring the launch alongside a jetty situated on the left
bank of the river.
I would come down on the right bank as that is the side of the fairway
which will now be on my starboard side. On nearly reaching the jetty I
would alter course to turn the boat’s head towards it as the boat would
be carried downstream when she got athwart the tide. I would then
approach the jetty head on to tide, and when abreast of it, slow down
the engine to stem the tide and sheer gently alongside.
MOTOR BOAT RULE OF THE ROAD.
(To be committed to memory )
Art. 18—When two steam vessels are meeting end on. or nearly
end on, so as to involve risk of collision, each shall alter her course
to starboard, so that each may pass on the port side of the other. c
This Article only applies to cases where vessels are meeting end on,
or nearly end on, in such a manner as to involve risk of collision, and
does not apply to two vessels which must, if both keep on their respective
courses, pass clear of each other.
The only cases to which it does apply are when each of the two
vessels is ?nd on to the other; in other words, to cases in which, by day,
each vessel sees the masts of the other in a line, or nearly in a line,
with her own; and, by night, to cases in which each vessel is in such
a position as to see both the side-lights of the other.
It does not apply, by day, to cases in which a vessel sees another
ahead crossing her own course; or, by night, to cases where the red light
of one vessel is opposed to the red light of the other, or where the green
light of one vessel is opposed to the green light of the other, or where
a red light without a green light, or a green light without a red light,
is seen ahead, or where both green and red lights are seen anywhere but
ahead.
Art. 19. —When two steam vessels are cr6ssing, so as to involve
risk of collision, the vessel which has the other on her own .starboard
side shall keep out of the way of the other.
96
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Art. 20.—When a steam vessel and a sailing vessel are proceeding
in such directions as to involve risk of collision, the steam vessel shall
keep out of the way of the sailing vessel.
Art. 21.—Where by any of these Rules one oi two vessels is to keep
out of the way, the other shall keep her course and speed.
Note. —When, in consequence of thick weather or other causes,
such vessel finds herself so close that collision cannot be avoided by
the action of the giving-way vessel alone, she also shall take such
action as will best aid to avert collision.
1. You are in charge of a motor launch, what would you do in each of
the following cases when there is risk of collision—
(a) When meeting another launch end on?
(b) A launch crossing on your starboard bow?
(c) A launch crossing on your port bow?
(d) Approaching a boat under sail so as to involve risk of collision?
Ans. (a) Alter course to starboard. (6) Keep clear by altering
course to starboard. ( c) Stand on. (d) Keep clear.
Fig 7.— (a) Meeting end on. ( b ) Crossing vessels
USE OF OIL FOR MODIFYING THE EFFECT OF
BREAKING WAVES
The Board of Trade desire to call attention to the following infor- *
mation, which has been published by the Admiralty in their Sailing
Directions, on the Use of Oil for Modifying the Effect of Breaking.
Waves:—
“Many experiences of late years have shown that the utility of oil
for this purpose is undoubted, and the application simple.
USE OP OIL ON BREAKING WAVES
97
“The following may serve for the guidance of seamen, whose atten¬
tion is called to the fact that a veiy small quantity of oil, skilfully
applied, may prevent much damage, both to ships (especially the
smaller classes) and to boats, by modifying the action of breaking seas.
“The principal facts as to the use of oil are as follows:—
“1. On free waves, i,e , waves in deep water, the effect is greatest.
“2. In a surf, or waves breaking on a bar, where a mass of liquid is in
actual motion in shallow water, the effect of the oil is uncertain,
as nothing can prevent the larger waves from breaking under
such circumstances; but even here it is of some service.
“3. The heaviest and thickest oils are most effectual. Refined
kerosene is of little use; crude petroleum is serviceable when
nothing else is obtainable; but all animal and vegetable oils,
such as waste oil from the engines, have great effect.
“4. A small quantity of oil suffices, if applied in such a maimer as to
spread to windward
“5. It is useful in a ship or boat, both when running or lying to, or
in wearmg.
“6. No experiences are related of its use when hoisting a boat up in
a seaway at sea, but it is highly probable that much time and
injury to the boat would be saved by its application on such
occasions.
At anchor, when the sea is sufficient to render it difficult to hoist
up or to launch boats, oil bags from forward or from the
swinging booms have been found to render the sea alongside
comparatively smooth.
“7. In cold water, the oil, being thickened by the lower temperature,
and not being able to spread freely, will have its effect much
reduced. This will vary with the description of oil used.
M 8. The best method of application in a ship at sea appears to be—
hanging over the side, in such a manner as to be in the water,
small canvas bags, capable of holding from 1 to 2 gallons of oil,
such bags being pricked with a sail needle to facilitate leakage of
the oil.
“The position of these bags should vary with the circumstances.
Running before the wind they should be hung on either bow—
e.g., ffom the cathead, and allowed to tow in the water.
“With the wind on the quarter the effect seems to be less than in any
E
98
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
other position, as the oil goes astern while the waves come up on
the quarter.
“Lying-to, the weather bow, and another position farther aft seem
the best places from which to hang the bags, with a sufficient
length of line to permit them to draw to windward, while the
ship drifts.
“9. Crossing a bar with a flood tide, oil poured overboard and allowed
to float in ahead of the boat which would follow with a bag
towing astern, would appear to be the best plan. As before
remarked, under these circumstances the effect cannot be so
much trusted.
“On a bar with the ebb tide it would seem to be useless to try oil
for the purpose of entering.
“10. For boarding a wreck, it is recommended to pour oil overboard
to windward of her before going alongside. The effect in this
case must greatly depend upon the set of the current, and the
circumstances of the depth of water.
“11. For a boat riding in bad weather from a sea anchor, it is recom¬
mended to fasten the bag to an endless line rove through a block
on the sea anchor, by which means the oil is diffused well ahead
of the boat, and the bag can be readily hauled on board for
refilling if necessary.
“12. Towing a vessel in a heavy sea, oil is of the greatest service, and
may prevent parting the hawser. Distribute from the towing
vessel forward and on both sides; if used only aft the tow alone
gets the benefit/' 5 '
BOAT CONSTRUCTION
99
SECTION II.—SHIP’S BOATS.
From Board of Trade Regulations
LIFE-SAVING APPLIANCES.
Details of Boat Construction.
Section Through Gunwaie and Topsides
Cappinc
Through Bolt J
Through Bolt
Hard wood chock
Side bench
behind knees
r*
Hard wood chock
between timbers
Filling piece
Sheer s trake
Rubber
Upper strake of planking
FtUing piece
Filling piece
St rake orplanking
Fig. 8.
The above sketch represents a section of the gunwale and topsides
of a clincher built boat, the names of the different parts being clearly
indicated.
It must be understood that it shows how they would appear if the
topside of the boat was cut through in a direction at right angles to her
keel.
Half Midship Section of Clincher Built Boat.
Note the following parts:—
The timber.—Generally of American elm, ash, or oak. In boats
of 29 or 30 feet in length the size would be about l^Xl inch. Except
at the ends of the boat, this is fitted in one piece from gunwale to gunwale.
The keel.—Of American elm or oak required to be fitted in one
100
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
piece. In boats of 29 or 30 feet in length the size would be almost
6x3 inches.
The hog piece. —Of elm or oak, about 5x1 inch in large boats.
The keelson. —Of elm, oak, or pine, about 5x3 inches in large boats,
The bilge stringer. —Of elm, larch, or pitch-pine £ inch thick and 3 to
4 inches wide.
The through bolt passing through keelson, hog piece, and keel.
The filling pieces underneath the landing edges of the planking.
BOAT CONSTRUCTION
1 01
Arrangement of Stem, Apron, Etc.
Construction of the Fore End of a Boat.
The small double line on the stem is the iron stem band.
The line separating the apron from the stem indicates the position
of the rabbeting for taking the ends of the planking.
The three small shaded pieces are the timbers.
The fitting with the three through bolts is for the attachment of the
lifting hook. Note that in this case the stem band is extended far
enough aft to take the heads of these bolts. If not extended so far, a
separate plate must be fitted.
L03 NTCHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Arrangement of the Stem.
The construction of the stem is very similar to that of the stem.
The line separating the apron from the stempost indicates the
position of the rabbeting for taking the ends of the planking.
Note the iron stem band. This is fitted from a point just under the
lower gudgeon round the keel, under the keel, and extends far enough
forward to take the three through bolts securing the lifting hook
attachment.
The three shaded pieces are the timbers which lie on top of the hog
piece but underneath the keelson.
BO AX CONSTRUCTION
103
Boat Construction.
i In what way does a “ carve! built” boat differ from one that is
“clincher built?**
As regards construction.,, the principal and most noticeable difference
is in the arrangement of the planking. In a carvel built boat the edges
(and ends) of the planks butt squarely up against each other, and are
not overlapped as in a clincher built boat. The planking is laid close
on to the timbers, and shows a smooth flush surface both inside and
outside.
In a clincher built boat, each strake of planking has a landing
edge on the strake next below it. This leaves a vacant space of tapered
shape inside the boat between each timber and strake of planking, and
an uneven surface on the planking. It is, however, a strong system of
construction on account of the many doublings formed by the landing
edges of the strakes
In sailing qualities the carvel built boat is faster than the one which
is clincher built, but the latter on account of the small rolling chocks
formed by the plank edges is steadier in the water.
2. In what way does the procedure of building a ship differ from
that of building a clincher built boat?
When building a ship, after the keel is laid the frames are erected,
plumbed, and homed, and the plating is secured and riveted to the
frames.
In the case of a clincher built boat, part of the procedure is reversed,
that is, the planking is done first, the frames (timbers) being steamed and
put in afterwards.
How many thwarts are required to be fitted in a boat?
The number depends on the length of the boat.
18 feet in length and under 4 thwarts
over 18 and not above 24 feet 5 thwarts
over 24 and not above 28 feet 6 thwarts
over 28 and not above 30 feet 7 thwarts
4. How much “rise of floor” is generally given to a life-boat ?
Six inches in 4 feet.
5. Describe the kinds of wood which are commonly used for planking
Yellow pine, larch, "wych elm, teak, or mahogany. It must be
104
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
of the best quality, well seasoned, free from sapwood, shakes, ana
objectionable knots.
6. Bo the Board of Trade make any limit to the width of the planking
in a clincher built boat?
Yes. The extreme breadth of a plank is not to exceed inches
except in the four strakes next to the keel, of which two may be
7 inches, one inches, and one 6 inches.
In boats 18 feet in length and under the breadth is reduced by
about 1 inch.
The landings should not be less than f of an inch in breadth.
7. What is the thickness of the planking in a clincher built boat?
It varies between \ and f of an inch. The eight bottom strakes
(four on each side of the keel) are generally iV of an inch thicker than the
other planks in the same boat.
8. What is the spacing of the plank edge fastenings?
Not less than 3| inches. One fastening goes through each timber
and one between each timber through both edges of every plank.
9. Describe the fitting of the timbers, and how they are secured to the
planking?
The timbers are made of hard wood, l|xl inch in large boats,
steamed and bent to shape. They are fitted on top of the hogging but
underneath the keelson, and except at the extreme ends of the boat
must be in one continuous piece from gunwale to gunwale
They must not be spaced wider than 6 inches centre to centre, and
all fastenings must be of best wrought copper properly clenched on
rooves.
In ordinary clincher built boats the timbers are secured to the
planking by one fastening in each side of every plank.
10. What woods are boat knees made from?
Oak, ash, or elm, grown to form. Grown to form means that they
must be cut from wood having a natural bend, and not from a plank,
in which case some part of them would have to be cut across the grain.
11- How are the knees fitted and secured?
They are fitted above the side bench and thwart, the horizontal
part being secured with a bolt passing through the three thicknesses,
BOAT EQUIPMENT
1(
also by other fastenings The vertical part is secured by two “iforqug
bolts, the lower one being worked through the rubbing piece whSre* ii
head is countersunk. The knees are frequently formed of galvanise
iron bar bent to an angle of 90 degrees.
12. What are the “ risings?” Describe where and how they ar
fitted]
The risings are fore-and-aft pieces of elm, oak, larch, or pitch-pine
which must not be less than 1 inch in thickness, and 3 to 4 inches deep
They are like heavy stringers fitted one on each side fore and aft, anc
fastened at each timber with a through fastening or brass screw. The
ends of the thwarts rest upon them, and are attached to them by means
of two screws at each end.
BOAT EQUIPMENT
13. What equipment is required for life-boats carried by foreign-going
vessels]
A full single-banked complement of oars and two spare oars, also
a steering oar. The steering oar should be 1 foot longer than the
other oars, and the blade should be painted to distinguish it.
Two plugs for each plughole, attached with lanyards or chains.
One set and a half of thole pins or crutches, attached to the boat by
sound lanyards. x
A sea anchor, a bailer, and a galvanised iron bucket.
A rudder and a tiller, or yoke and yoke lines.
A painter not less than 20 fathoms in length, and a boathook.
Two hatchets.
A lantern tr imm ed, with oil in its receiver sufficient to burn for
8 hours.
A vessel which is to be kept filled with fresh water, and capable of
holding one quart for each person that the boat is fit to carry.
A line securely becketted round the outside.
A mast or masts, with at least one good sail and proper gear for each.
An efficient compass.
An airtight case containing 2 lbs. of biscuits for each person.
One gallon of vegetable or animal oil, and a vessel of approved
pattern for distributing it on the water in rough weather. This vessel
shall be capable of being attached f o the sea anchor.
106 NICKOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
One 1 lb. tin of condensed milk for each person the boat is certified
to carry.
One dozen self-igniting red lights in a watertight tin, and a box
of suitable matches in a watertight tin.
14. What is a rowlock?
A rowlock is a small open space on top of the gunwale made to
provide a suitable place for shipping and pulling the oars m. It may
be formed by pieces of wood fitted on the gunwale, or by pieces being
cut out of the gunwale. Rowlocks are often fitted in naval boats, and
in those used by fishermen and watermen, but not in boats of the
Mercantile Marine. The latter are fitted with “crutches’ 5 or “thole¬
pins 55 which serve the same purpose.
15. What are the regulations relating to the mast?
It must be a Norway spar, the length of which is not to exceed two-
thirds the length of the boat.
It should be fitted with the necessary stays and sheaves.
The sheave for lugsail halyard should be not less than 12 inches
above the yard when the sail is set, and the jib halyard sheave should
be not more than 12 inches below the truck.
16. What is meant by an approved life-buoy?
An approved life-buoy shall be of solid cork or other equivalent
‘ material. It shall be capable of floating in fresh water tor at least
24 hours with 32 lbs. of iron suspended from it.
It shall be painted in good distinguishable colours such as white or
red.
The inside diameter shall not be less than 18 inches.
It shall be fitted with beckets securely seized on to it. At least one
on each side of the ship shall be fitted with a life-line not less than 15
fathoms in length.
17. What are the general specifications of efficient life-boats?
They must be properly constructed with materials approved by *
the Board of Trade, and be of such form and proportions that they
have ample stability in a seaway, and sufficient freeboard when loaded
with their full complement of passengers and equipment.
Their structural strength must be sufficient to permit them being
BOAT EQUIPMENT
1C
safely lowered into the water with the full complement of person
and equipment on board.
Buoyancy apparatus shall be constructed of copper or yellow meta
of not less than IS ounces to the superficial foot. The tanks are coate(
with boiled linseed oil or varnish to preserve them. Boats to hav<
a capacity of not less than 125 cubic feet.
18. What type of boats are specified as Class 1?
There are three different types named A, B, and C.
Type A.—Open life-boats with internal buoyancy only. The buoy¬
ancy of a wooden boat of this type shall be provided by watertight
air-cases, the total volume of which shall be at least equal to one-tenth
of the cubic capacity of the boat.
Type B.—Open life-boats with internal and external buoyancy.
The internal buoyancy of a wooden boat of this type shall be provided
by watertight air-cases, the total volume of which shall be at least
equal to 7^ per cent of the cubic capacity of the boat.
If the external buoyancy is of cork, its volume for a wooden boat
shall be not less than thirty-three thousandths of the cubic capacity
of the boat; if of any material other than cork its volume and distribution
shall be such that the buoyancy and stability of the boat are not less than
that of a similar boat provided with external buoyancy of cork.
In the case of a metal boat of both A and B types, an addition
shall be made to the cubic capacity of the airtight compartments so as
to give it buoyancy equal to that of the wooden boat.
Type C.—Pontoon life-boats having a well deck and fixed watertight
bulwarks. The area of the well deck of a boat of this type shall be at
least 30 per cent, of the total deck area. The freeboard shall be such
as to provide for a reserve buoyancy of at least 35 per cent.
19. What type of boats are specified as Class 2?
There are three different types named A, B, and C.
Type A.—Open life-boats having the upper part of the sides collapsible.
A boat of this type shall be fitted both with watertight air-cases and
with external buoyancy* the volume of which for each person which
the boat is able to accommodate shall be at least equal to the following
amounts:—
Air-cases - 1*5 cubic feet.
External buoyaney (if of cork) 0*2 cubic feet.
108
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
The freeboard of boats of this type depends on their length, and in
fresh water shall not be less than the following amounts:—
Length of the boat in feet. Minimum freeboard in inches.
26 8
28 9
30 10
Type B.—Pontoon life-boats having a well deck and collapsible
bulwarks. All the conditions laid down for boats of Class 1, C, shall
be applied to boats of this type, which differ from those of Class 1, C,
only in regard to the bulwarks.
Type G.—Pontoon life-boats having a flush deck and collapsible
bulwarks. The minimum freeboard of boats of this type is independent
of their length, and depends only on their depth. The freeboard in
fresh water shall not be less than the following amounts:—
Depth of the boat in inches. Minimum freeboard in inches.
12
18
24
30
2 |
20. What type of boats are specified as Class 3?
Open boats which have not the buoyancy required for life-boats of
Class 1.
21. How many boats are required to be carried by a foreign-going
steamer?
Such number, and of such aggregate capacity as shall be sufficient
to accommodate the total number of persons which is carried, or which
the ship is certified to carry, whichever number is the greater.
When the number of life-boats is more than 10, one of them shall
be fitted with an approved wireless telegraphy installation.
When the number of life-boats is more than 13, one shall be a
motor boat; and when the number is more than 19, two shall be motor
boats.
All motor boats shall be fitted with wireless telegraphy and
searchlights. ,
22. How many sets of davits are required to be carried by a foreign-
going passenger steamer or emigrant ship?
LIFE-SAVING APPLIANCES
109
The number of sets of davits depends upon the length of the vessel.
Subject to various modifications, a few examples are given below:—
Registered length of ship in feet. Minimum number of sets of davits.
100 and under 160
2
160
„ 190
3
190
„ 220
4
300
„ 330
8
370
„ 410
10
460
„ 520
14
C40
„ 700
20
960
„ 1030
30
Provided that no ship shall be required to have a number of sets of
davits greater than the number of boats required to accommodate the
total number of persons which is carried, or which the ship is certified to
carry, whichever number is the greater.
23. How would you find approximately the cubic capacity of an open
life-bo at 1
« Measure the length and breadth outside and the depth inside, in
feet. Multiply them together and by -6; the product may be
assumed to be the capacity of the boat in cubic feet.
The formula would be written down. Lx BxDx *6=capacity;
where L— length, R=breadth, D=depth (all in feet).
24. Find the cubic capacity of an open life-boat which has measure
ments of 24 feet by 7 feet 6 inches by 3 feet.
Length 24 feet
Breadth 7*5 feet
120
168
180*0
*3 depth
540*0
-6
324*00 cubic feet
110 NIOBlOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
25. How would you determine the number of persons which a life¬
boat is fit to carry?
By finding her cubic capacity in feet, and dividing it by 9 in the
case of boats of Class 1, B, but by 10 in the case of all others.
26. A life-boat has a cubic capacity of 360 feet. How many persons
is she fit to carry?
If of Class 1, B, she will carry 40 persons, if of any other class she
will carry 36 persons.
27. Is a life-boat required to be marked in any particular way?
Yes. All boats shall be permanently marked m such a way as to
indicate plainly their dimensions and the number of persons for which
they are approved. The marking should be cut on the stem or sheer-
strake on one side of the boat, and the number of persons for which they
are approved should be cut on the other side.
28. What is meant by a boat’s “coefficient of fineness”?
The ratio which the cubic capacity of the boat bears to the cubic
capacity of a rectangular block of the same extreme dimensions.
value which is generally about ’6 gives some idea of her shape and the
fineness of her lines. If she was round in the counter and bluff in the
bow her coefficient of fineness would be greater than *6, if of very fine
lines it would he less.
29. How many life-buoys are required by a foreign-going passenger
steamer?
The number depends on her length.
If she is under 400 feet in length, at least 12.
If 400 but under 600 feet in length, at least 18.
If 600 but under 800 feet in length, at least 24.
If 800 feet or over, at least 30.
At least half the number of life-buoys required to be carried shall
have self-igniting life-buoy lights placed near them, and such lights are
to be provided with means for attachment to the life-buoys.
One life-buoy must be carried in beckets or cleats on each side
of the navigating, bridge in such a manner that they can be instantan¬
eously released, and will drop clear of the ship’s side. Each of these
life-buoys shall have a self-igniting lifebuoy light attached to it by at
least 12 feet of good line. Two buoys, one on each side, to be fitted
with life-lines 15 fathoms in length*
LIFE-SAVING APPLIANCES
Ill
30. How many life-buoys are required to be carried by a foreign-going
steamer not certified to carry passengers?
Not less than six At least half the number shall have self-igniting
life-buoy lights placed near them, such lights to be provided with
means for attachment to the life-buoys.
One life-buoy must be carried on each side of the navigating bridge,
and must be fitted m exactly the same way as m passenger steamers.
31. Give a brief description and specification of a life-jacket,
A life-jacket is a life-saving appliance to be fitted on the wearer's
body, and secured in position by means of tapes.
The required buoyancy may be supplied by cork, kapok, or other
approved substance, but must not depend on air compartments.
The covers may be of cotton, linen, or other approved material.
The tapes, two m number, must be of linen or cotton thread web
l£ inches wide, not less than 110 inches long. They must be capable
of bearing a strain of 200 lbs.
The sewing must be done with good quality thread, the ends of the
stitching being securely finished off.
The weight of a Standard kapok life-jacket should not exceed
2 lbs. 4 ozs., and the weight of a Standard cork life-jacket should not
exceed 5 lbs. 4 ozs.
The buoyancy must be so distributed that when the wearer is inert
in the water the position of the body should be as near the vertical
as possible.
It should be so arranged that it will keep the wearer's head clear
of the water when floating in the inert position.
In the event of the wearer being rendered unconscious, the head
should be so supported that it would not fall forward and the face become
submerged.
The jacket must be reversible, Le., it must satisfy the above con¬
ditions even if it is adjusted on the wearer back to front or upside
down.
32. What is meant by an approved life-jacket?
An approved life-jacket shall mean a jacket of approved material
and construction which is capable of floating in fresh water for 24
hours with 16£ lbs. of iron suspended from it, or any other approved
appliance of equal buoyancy and capable of being fitted on the body.
112
NTCHOLI.S’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
33. Who is responsible for seeing that all passengers and all members
of the crew are properly instructed in the adjustment of the
life-jackets on board?
The master.
34. How many life-jackets are required to be carried by a foreign-going
steamer?
One approved life-jacket for every person on board, and if a passenger
steamer &n additional and sufficient number of approved life-jackets of
a suitable size for children.
35. Who has the authority for appointing officials to inspect life¬
saving appliances?
The Board of Trade. These officials are called Board of Trade
Surveyors (or inspectors).
36. May a ship surveyor inspect a ship’s life-saving appliances?
Yes. And for the purpose of that inspection he shall have all the
powers of a Board of Trade inspector.
37. What general precautions (as regards her life-saving appliances)
aTe to be taken to ensure, as far as possible, the safety of a
vessel’s passengers and crew?
Passengers and crew should be properly instructed in the use of
the life-saving appliances provided for them.
Life-jackets for every person on board must also be kept in some
known place where they are always readily accessible.
All life-saving appliances must be periodically examined for the
purpose of seeing that they are fit and ready for use.
An officer told ofi for the purpose shall be responsible for examining
all the boats and their equipment once a week.
In foreign-going passenger ships musters of the crew shall be held
at least once a week when practicable either in port or at sea. (Once
a fortnight in cargo ships.)
MusteT lists showing the stations and duties of each member of the
crew shall be posted up in the crew’s quarters and other conspicuous
places.
Sufficient members of the steward’s department are to be told ofi
fox the effective mustering of passengers.
Boat drill jnust be practised. The master must enter in the official
log book a statement of every occasion on which boat drill is
LIFE-SAVING APPLIANCES
113
practised on board tlie &hxp and on which life-saving appliances have
been examined. Penalty for failing to comply with this requirement,
a fine not exceeding £10.
38. Is the master liable to any other penalty for breach of rules
regarding life-saving appliances?
Yes. If he is in fault he is liable to a penalty of £50, and the
owner if in fault is liable to a penalty of £100 for any of the following
offences'—
If the ship proceeds on any voyage without being supplied with
life-saving appliances in accordance with the rules applicable to the
ship, or
If any of the appliances with which the ship is so provided are lost
or rendeicd unfit for service through the wilful fault or negligence of the
owner or master; or
If the master wilfully neglects to replace or repair on the first oppor¬
tunity any such appliances lost or injured m the course of the voyage; or
If such appliances are not kept so as to be at all times fit and ready
for use.
39. What points have to be considered when deciding upon the positions
m which boats are to be carried and lowered?
They should be carried in positions where they are easily accessible,
and can be manned and lowered quickly, the safe embarkation of
passengers being carefully studied.
They must be high enough above the water to ensure them being
reasonably safe from damage in bad weather.
They should not be placed where, when being lowered into the water,
there is any chance of them being swamped by water from condenser
or pump discharges.
Projections on the ship's side must also be considered, and positions
chosen where such projections (if any) are small and not liable to prove
dangerous.
Where this is impracticable, dangerous projections should be
removed or modified in design. If this cannot be done, all boats which
are stowed above such projections must be fitted with efficient
vertical fenders.
When boats are lowered care must be taken that they are not in
dangerous proximity to a propeller.
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
114 *
40. What is done to guard against the edges of the-planking being
caught by the edges of the ship’s plating when a boat is being
lowered?
The overhang of davits must be such as will admit when the vessel
is upright of a minimum clearance in lowering of 1 foot between the
ship s side and that of the boat. When the ship is fitted with a heavy
“rubber” or "belting” the clearance must not be less than 6 inches.
"Filling pieces” of curved form on the outside are also fitted to the
boat underneath the landing edges of the planking for about one-third
of her length amidships. These extend from the bilge to the gunwale,
and are a further safeguard. *
. Tie men in the boat would also assist in keeping her clear of the
ship’s side.
41. Describe the sea anchor of a life-boat?
It consists of a bag made of good quality canvas formed in the
shape of a cone. The mouth of the bag has a diameter of between
2 feet and 2 feet 6 inches, and is kept open by being sewn round a gal¬
vanised iron or wooden ring. A double bridle is spliced round this' 1
ring in four places, eyelet holes at equal distances apart being made
m the canvas for this purpose. To the bights of this bridle 15 to 20
fathoms of 2|~inch rope are secured to act as a cable. A small opening
is left at the point of the sea anchor through which some water escapes
as the boat slowly drives to leeward. A tripping line of light stufi is
spliced into a becket also at the point of the sea anchor for the purpose
of hauling it in. See figure 8, page 119.
CHAPTER VII.
ANCHORS AND CABLES.
Anchors are made of forged wrought iron, or forged open hearth
ingot steel, or cast steel and are marked on the crown (or head) and
shank showing the maker’s name or initials, progressive number, and
weight. All anchors are tested as to their strength, the stram imposed
on them varying with their size.
All cast steel anchors are also subjected to percussive, hammering,
and bending tests. They must also be annealed and stamped “Annealed
Steel.”
All steamers, except very small ones, have to carry two bower
anchor, also one spare bower anchor, and a stream anchor. Sailing
vessels have to carry the same, with a kedge in addition. The stream
anchor is about one-third the weight of the bower.
The spare anchors are stowed and well secured in some convenient
position where they can easily he got at. The spare bower is carried
on the forecastle-head or fore deck. In steamers where it is likely to
be required for stern moorings, the stream anchor is generally carried aft.
Some vessels have been fitted with a windlass, stream chain and a
hawsepipe at the stem when specially equipped for trading to ports
where stem moorings are required.
The principal parts of an anchor are shank, crown, arms, flukes or
palms, bills or peas, stock, ring or shackle, forelocks. (See illustrations
on next page.)
The weight of a steamer’s anchors depends on the size and type
of the vessel. The following is a rough approximation. In some cases
one bower and the spare bower may be less than the given weights.
Length
Bower anchors
Stockless
Stream anchor
of vessel
without stock
anchors
without stock
(in feet)
(in cwts.)
(in cwts.)
(m cwts.)
290
28J
35J
375
42
52J
14
480
65
81J
23J
In small steamers the anchors will be lighter, and in very large
steamers much heavier than the weights given above.
115
116
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
.The anchor stock must be equal to one-fourth the specified weight
of the anchor. It will be noted that this brings the weight of the
anchor with stock up to approximately the same as the stockless anchor.
The stock is to help the anchor to bite and get a good hold of the ground.
Should the anchor fall with its arms flat, the stock will be upright, and
as soon as any weight comes on the cable, the stock being heavy and
longer than the arms, it will turn the anchor. This is the best holding
type of anchor and the longer the shank the better it holds; it is, however,
awkward to handle and stow on the forecastle-head.
Stockless Anchors.—Figure 3 shows a Lenox unchokeable stock¬
less anchor; this type of patent anchor is now universally adopted
in modern steamships. It consists of a heavy head having arms and
flukes generally forged in one piece with it, also a shank and shackle.
The head is made to turn on an axis perpendicular to the shank,
the arms moving in a plane parallel to the shank, being in line with it
when in the closed position.
It is so constructed that the head will turn on its axis and the arms
will open out to an angle of 45° with the shank, but no further.
The head must weigh not less than three-fifths of the total weight
of the anchor.
ANCHORS AND CABLES
117’
^ hen the anchor is let go, the strain on the cable causes the arms
to open out and the flukes to bite into the ground.
. .^ e a ^ vanta ge of a stockless anchor over one fitted with a stock
in the ease of handling it, and the amount of work which is saved
Fl S* 3 —Patent Stockless Anchor.
by its use. Instead of having to be taken on board by a crane and
bedded and secured every time the anchor is lifted, it is hove right up
into the hawsepipe and remains there. If the anchor is likely to be
required again shortly it would be held by the windlass well screwed up
or by the chain being put in the bow stopper from which it could be’
quickly released. If not, it could be hung off with the “devil’s claw”
or a chain stopper, or chain lashing.
Fig. 4.—Bow Stoppers.
A stout iron-bar passed through the big link or any other link in the
cable, and restmg on the top of the hawsepipe, would also hold it and be
a safeguard against accident.
Permanent Mooring Anchors for buoys and beacons in shallow
water have usually one fluke only and the anchor is lowered to the
118
NICHOLL&’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
bottom fluke downwards, by means of a slip rope rove through a shackle
in the crown. A screw mooring is sometimes used for the same purpose.
Fig. 5.—One Fluke Moonng Anchor.
Lightvessels round the coasts are generally moored with two mush¬
room anchors which bury themselves in the bottom. The cables
from each hawsepipe are shackled to the upper li^ka 0 f a swivel
ANCHORS AND CABLES
119
and the cables from each mushroom to the lower links. The swivel
turns when the vessel swings round to the tide and so prevents the
cables twisting round each other thus ensuring a “clear” hawse.
Fig 7.—Mushroom Anchors.
A Sea Anchor is simply a tapered canvas bag the small end being
also open. It is part of the compulsory equipment of ships’ life-boats
and is thrown out ahead of the boat with a line attached to the bridle
to keep the boat head on to wind and sea when it is impossible to make
headway against the wind* A small canvas bag with needle holes
Fig. 8.—Sea Anchor*
punctured in it and filled with oil is lashed to the sea anchor, and the
oil, spreading on the surface of the water, helps to smoothen the sea in
the track of the boat and makes conditions more comfortable.
Chain Gable is measured by the diameter of the iron forming the
links. Studs are fitted in the links to keep chain from kinking and,
incidentally, they add to its strength. The size of cables for a steamer
depends upon the size and type of the vessel. The following table
120
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
will give an approximate idea as to both size and length of chain
provided.
Length of steamer Length of cable Size of cable
m feet. m fathoms in inches
290 240 1£
375 270 2-iV
480 300 2£
Larger steamers have longer and heavier cables. The Mauretania
has 330 fathoms, the size being 3f inches.
The cables of sailing ships are heavier, and they carry 30 fathoms
more than steamers of corresponding size.
Lloyd’s Rules regulate the sizes of all anchors and cables for both
steam and sailing vessels according to their equipment number. This
is their longitudinal scantlmg number with an allowance for super¬
structures added to it. The corresponding approximate lengths
quoted above have been given here, as they are more easily noted and
understood.
The length from shackle to shackle in the cable is^ 15 fathom^ in
merchant ships, 12^- fathoms in warshipsj the shackles being placed
in the cable with the bow or round end of the shackle forward so that'
it goes out first.
SHACKLES.
The shackles which join the lengths of cable together difier slightly
from those used for shackling it to the anchor. In the joining shackles
Fig. 9.—Swivel link.
ANCHORS AND CABLES
121
the pin does not project beyond the width of the shackle, and is secured
by a hard wood plug passing through the pin and one lug of the shackle.
The anchor shackle is larger than the joining shackles, and the pin
projects through the lug on one side, being secured by a ring or forelock.
In some of the latest ships there is no difference.
The lengths of cables are marked in succession as follows:—At the
first shackle (15 fathoms) by a piece of seizing wire on the stud of the
first link abaft the shackle; at the second shackle (30 fathoms) by a
piece of wire on the second studded link abaft the shackle; at the third
shackle (45 fathoms) by a piece of wire on the third studded link, and so
on.
All the marked links are sometimes painted white so that they
may be more easily noted when the cable is running out.
Fig 10.—Senhouse Slip.
The inboard end of the cable is generally shackled to a good eyebolt
in the collision bulkhead at the bottom of the chain locker. A lashing
of small chain is sometimes used, and is better than the shackle as it
can easily be let go in case of emergency, although a Senhouse slip link
is best.
INSPECTION OF ANCHORS AND CABLES.
Vessels undergo a periodical survey every four years by one of the
two classification societies, Lloyd’s or the British Corporation, under
which British vessels are registered. The hull, machinery and deck
equipment are then inspected. The chain cables are ranged for inspection
and anchors and chains examined and placed in good working order.
If any length of chain cable is found to be reduced in mean diameter by
10 per cent, of its original size at its most worn part it is to be renewed.
The chain locker is examined internally.
The cable is ranged in long lengths up and down the bottom of the
dry dock, pins of shackles knocked out and examined, coated with
white lead and tallow and replaced with new wooden holding pins
driven into the pins of the connecting shackles. The links are sounded
122 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
by tapping with a hammer to hear if they give out a clear ring. It ia
desirable to occasionally replace the two or three lengths nest the
anchor with two or three lengths from the bottom of the locker as all
chain gets fatigued and brittle when lying idle. This also gives an
opportunity of cleaning out the locker. When dirty cable is being hove
up from a muddy bottom it should be hosed down as it enters the hawse-
pipe. It may be remarked here that at each survey the masts, spars,
rigging and general deck equipment are inspected, including hatch covers
and supports, tarpaulins, cleats and battens, ventilator coamings and
covers.
The Anchors and Chain Cables Act insists on rigorous tests being
applied to mooring cables, the responsibility for their efficiency, in the
first instance, being on the maker. The chain is made in 15 fathom
lengths with three additional experimental links; the sample links and
the length of cable must each be stamped with a distinctive identification
number.
The cable is taken to a testing establishment licensed by the Board
of Trade, and the three links cut out and submitted to the full breaking
strength, but only the proof test, which is about 70 per cent, of the tensile
breaking strength, is applied to the 15 fathoms length. The breaking
load is about 24 D 2 , D being the size of the cable chain in inches. * After
it has been tested the length of chain is measured for elongation and
each link separately examined by two inspectors for flaws, cracks,
broken or twisted studs, etc. The cable when passed is stamped
with the Board of Trade test marks and a full description of its length,
weight, size of the links and shackles and a record of the tests, makers’
name, ship’s name, etc., are recorded on the Cable Certificate which
must be carried on board the ship and produced when required.
A drop test is applied to anchors. The anchor is raised so that its
lowest part is at a height of 12 feet and then dropped on a steel or iron
slab. It is dropped side on, and then end on, and if this percussive test
is satisfactory the anchor is then slung up and hammered all over with
a 7 lb. sledge hammer to see if it gives a clear ring. This test is to
ensure that there are no flaws in the casting and that .none have been
developed by the drop tests.
The anchor when passed at a Lloyds Proving House licensed by
the Board of Trade is stamped with the Identification Mark of the
Proving House, the Certificate Number, the Number of the Tensile
Machine; Year Licence was granted; Proof Strain.
ANCHORS AND CABLES
123
Chain cables are stamped at every five fathoms with the same
information as for anchors and in addition the tensile and breaking
strains.
Spare Parts for Rod and Chain Steering Gear: By Agreement between
the Shipping Federation and the Ministry of Shipping.
Ships under 12 knots .—
1 complete spring buffer and 1 spare spring.
2 tested chains equal to the longest length in the gear or, alter¬
natively, 1 spare set of all the lengths on one side.
2 bottle screws; 2 sheave pins.
4 shackles; 4 connecting links, 4 rod pins.
Ships over 12 knots and all H.T. Ships and Coasting Vessels .—
1 tested chain equal to the longest length in the gear.
1 spring buffer, 1 bottle screw.
4 shackles; 4 connecting links; 4 rod pins.
2 sheave pins.
QUESTIONS.
1. What materials are anchors made of?
2. What marks are stamped on anchors after having been tested?
3. Describe the anchors carried by a steamer, where stowed and
their special purpose.
4. Name the parts of an anchor fitted with a stock, and also the
parts of a stockless anchor.
5. What was the weight of the anchors in any ship you have served
in and the length of her cable chains?
6. Discuss the advantages and disadvantages of stock anchors and
stockless anchors.
7. Describe any forms of permanent mooring anchors you may
know of.
8. How may a patent anchor be securely held in the hawsepipe?
9. Who prescribes the size of anchors and cables a ship must have?
10. How are successive lengths of cable marked?
11. A new cable is brought to the ship: how can one tell which is the
chain locker end?
12. State what should be done occasionally with chain cables, shackles,
chain locker and anchor gear generally in order to preserve them as
much as possible.
13. State what you know of the Anchors and Chain Cables Act.
CHAPTER VIII.
DECK APPLIANCES AND APPARATUS.
Communication throughout a small ship is easily maintained by the
human voice, but the larger the ship the more difficult does it become
to maintain the rapid and eflective transmission of imperative order?
from the navigating bridge to the various parts of the ship. The
engine and docking telegraphs, telephones and the various signalling
devices to indicate the position of watertight doors, the failure of
navigation lights, the overheating of a compartment or the outbreak
of fire, are installed in the wheelhouse which, in effect, is the nerve
centre of the vessel.
Mechanical Telegraphs.—Orders are transmitted from the bridge
to the engine-room by means of a wire and chain telegraph The dial
casing covers a sprocket wheel keyed to a horizontal axle; the end of the
axle projects through the centre of the dial and is firmly attached to a
hand lever. When the lever is moved the wheel turns through a
corresponding arc of a circle. The links of a flat chain, similar to the
driving chain of a bicycle, engage with the sprockets of the wheel and
the ends of the chain which hang down inside the pillar, are connected
by means of tightening screws to wires led in the most convenient
and direct way to a similar telegraph in the engine-room (Fig. 1).
In the event of the bridge and engine-room telegraphs not registering
the same co mm and it would be necessary to unscrew the brass panel on
the pillar of the bridge telegraph, slacken back one of the connecting
screws and tighten the other one until the reply pointer and the command
pointer came together.
The dial is marked Ahead and Astern for “Slow,” “Half,” “Full”
and also “Stand By,” “Stop,” “Finished with Engines.” When the
lever is moved to half ahead the pointer on the engine-room telegraph
also moves to half ahead and a bell rings to .attract attention. The
engineer then replies by moving the lever of his telegraph to half ahead
and by doing so operates the return pointer on the bridge telegraph
which rings a .bell, thus indicating to the officer that the order has been
understood and is being executed.
124
1*—Bridge and Engine-room Telegraph,
126 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Docking Telegraphs are fitted in big ships, usually one at the stem
and sometimes another at the bow. They are geared to their corres¬
ponding telegraphs on the bridge in the same way as the engine-room
telegraph. The dials are marked so as to distinguish clearly between
the mooring ropes on the starboard side and those on the port side as
indicated in the adjoining illustration which, in this case, admits of
the following orders being transmitted from the bridge to the officer
attending to the mooring of the ship.
Fig. 2 —Docking Telegraph.
Astern
Not Clear
Heave in Stem Hope
Heave in Spring
Make fast Stern Rope
Make fast Spring
All Fast
Ahead
All Clear
Slack away Stern Rope
Slack away Spring
Let go Stern Rope
Let go Spring
Finished with Engines
TELEGRAPHS
m
It is the usual practice when docking to station the third officer on
the bridge to work the telegraphs as instructed by the captain or pilot,
the first officer at the fore end of the ship to work the forward hauling
lines, mooring wires and anchors, and the second officer at the stern.
In some passenger ships, however, the stations of the first and
second officers are reversed for the reason that the more experienced
and responsible officer is required at the stern as he is far removed from
the bridge and is usually hidden by deck erections from the sight of
those on the bridge, whilst, on the other hand, the bridge being well
forward, the officer in charge of the operations on the forecastle-head
is in full view from the bridge.
A Steering Telegraph, or Telephone, is sometimes fitted to transmit
helm orders from the flying bridge down to the wheelhouse, and also
telegraphs for communication between the engine-room and stokehold
regarding the firing of boilers.
A Navigation Light Sentinel is an apparatus which rings an alarm
bell should any of the navigation lights fail. It is electrically wired to
the masthead lights, side-lights and stem light, and should any one of
them go out a coloured disc in the indicator mounted m the wheelhouse
shows which particular light has failed to function.
THE LEADLINE.
The Hand Lead is about 7 or 8 lbs. in weight, and is for use in shallow
waters, or in channels or rivers, etc., where it is necessary to take
soundings frequently at short intervals, and without stopping. Profici¬
ency in heaving the hand lead can only be attained by considerable
practice. It should be hove on the weather side in a sailing ship; in
steamers or in vessels being towed it should be hove on the side on which
the shallowest water is expected.
The hand leadline is long enough to allow of soundings beirg taken
with it up to 20 fathoms, and is marked as under:—
At
2 fathoms
- 2 ends or strips of leather.
9J
3
»»
" " 3 „ „ 99
»
5
M
- - White rag (linen).
ft
7
9 »
- - Bed rag (bunting).
r»
10
99
- - Leather with a hole in it.
»
13
- Blue rag (flannel or serge).
h
15
**
- White rag (linen).
17
*r
- - Red rag (bunting).
»
20
»s
- Cord with 2 knots in
128
NICH(DLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
The fathoms 1, 4, 6, 8, etc , at which there are no marks are called
'"deeps,” but very often these are marked with short ends of marline
There are thus 9 mailzs and 11 deeps on the hand leadline In order
that the marks may be distinguished by feeling them, linen is used for
the white, bunting for the red and serge for the blue rag.
In marking a new line it should be opened out, and an eye spliced in
the end large enough' to slip over the lead, and then stretched and soaked.
To be strictly correct, the first measurement should be taken from the
end of the lead, but it is usually measured from the end of the line, in
order to give the ship what is termed the “benefit of the lead.” That
is to say, there is then a very slight error on the safer side. It would be
very dangerous to have marks too short, as it would indicate the water
to be deeper than it really was.
The markings of both the hand and the deep-sea leadlines should
be verified before use, and the line should be soaked first.
CALLING THE SOUNDINGS.
When the leadsman calls the soundings, he should always make the
number of fathoms the last part of the call. By so doing the officei
will generally get the number of fathoms , even though, through wind or
other causes, the first two or three words are not distinguished.
The report should be made as follows:—
6
fathoms
- by the deep 6.
61
- - and a quarter 6.
61
»*
- - and a half 6.
61
99
- - a quarter less 7.
7
99
- * by the mark 7.
U
99
- - and a quarter 7.
99
- and a half 7.
7f
99
- a quarter less 8.
8
99
- by the deep 8.
81
99
- and a quarter 8.
And so on.
THE DEEP-SEA LEAD.
The Deep-sea Leadline is marked similarly to the hand line up to 20
fathoms, after which every 10th fathom is marked by an additional knot,
and every intervening 5th fathom by a single knot. Thus:—
There is 1 knot at 25 fathoms. Ther* are 3 knots at 30 fathoms.
„ is 1 knot at 35 „ are'4 knots at 40 „
u is 1 knot at 45 „ are 5 knots at 50 „
SOUNDING MACHINES
129
and so on up to 100 or 120 fathoms. The 100 fathoms is marked by
leather with 2 holes, or with a piece of rag, after which the knots are
repeated
The deep-sea lead weighs from 28 to 30 lbs.
Both leads have cavities in their heels to admit of their being armed.
The deep-sea lead should always be armed before heaving, m order that
the nature of the bottom may be ascertained as well as the depth for
comparison with the chart.
TO TAKE A CAST OF THE DEEP SEA LEAD
The Ship’s Way through the water is stopped, the lead is carried
forward, the line is passed forward on the weather side outside of every¬
thing and made fast to the lead.
The Hands are stationed along the weather rail with a few bights of
the line in their hands When ready, the lead is dropped into the sea
and as the line is carried down by it each man in turn calls out “watch
there, watch,” as the line leaves his hand.
The Officer in charge has the line in his hand at about the expected
depth, and when the strain comes off the lines he gives the lead a dump
or two on the bottom to get a good up and down cast. He then
estimates the depth of water by the mark on the line, making
due allowance for the height of the ship’s rail above the sea level.
The line is then wound up on the reel as it is hauled in to be ready for
another cast should one be required. The tallow arming on the heel
of the lead is cut off and the nature of the bottom, be it sand (s), shell
(sh), mud (m), gravel (g), stone (st), coral (crl) is compared with that
given on the chart against the depth obtained. The depth of water and
the nature of the sea bottom when taken into conjunction with the
estimated position of the ship give the navigator some further assurance
as to his actual position. Fishermen in the North Sea grope their way
about and recognise particular fishing banks in this way.
The cast being satisfactory the ship gets under way again.
PATENT SEA SOUNDING MACHINES.
Most patent sounding machines are based on the fact that the
pressure of the water on an immersed body increases with the depth to
which it is immersed.
Boyle and Marriotte’s Law is made use of in some of them. Applied
to the sounding machine it may be stated briefly as follows:—The
130
NloHOLLS’S SEAMAN SHIP AND NAUTICAL KNOWLEDGE
volume of any given mass of air, or other gas, decreases in the same
proportion as the pressure upon it increases.
A glass tube, protected by a brass or copper case, is lowered to the
bottom with the aid of a sinker This tube contains air, and the inside
of it is coated with a chemical preparation called chromate of silver.
The tube is open at the bottom, and water is forced into it according to
the pressure to which it is subjected. The salt water discolours the
Fig. 3.—A Kelvin Sounding Machine, Electric Control.
chemical, turning it into chloride of silver, thus showing how far the
water has entered'the tube. By comparing this with a scale, which
is? supplied with the sounding machine, the depth to which the tube has
descended is read directly from the scale.
In another make* the water which enters the tube is retained, and
according to the water drawn up in the tube so the depth which the
tube has reached can be read from a scale which is supplied with it.
SOUNDING MACHINES
131
Another one, made of brass or copper, contains a spring, against
which a piston is forced up by the pressure of the water. The depth
is indicated by a pointer, which shows how far up the tube the piston
has been, and the corresponding number of fathoms is read off the tube
itself.
Most of the foregoing sounders can be used while the shi|? is going
at full speed, but the makers of some of them advise sh wing down to 8
ox 10 knots.
*5 <■
Fig. 4.—Side Boom to Enable Soundings to be made from the Bridge.
Some winches are fitted with a dial which registers the amount of
wire run out. A Table is provided which, when entered with the two
known factors, viz., speed of ship as the base line of a right-angled
plane triangle, and the wire run out as the hypotenuse, gives the depth
of water in fathoms (approximately) as the perpendicular side. It is
assumed that the sinker drops vertically to the bottom at the rate of
about 15 feet per second.
HOW TO TAKE A CAST WITH A PATENT SOUNDING
MACHINE.
Pass the sounding wire through the pulley on the rail at the stem
of the ship, or on the side-boom shackle the wire on to the short piece oi
rope spliced into the lead and to which is attached the brass container.
Put the glass tube into the container open end downwards. When ready,
hang the lead over the stem, release the brake on the winch and the wire
will run out free wheel. Keep feeling the wire with the brass feeler
132 NICHOLAS'S SEAMANSHIP ANI) NAUTICAL KNOWLEDGE
provided for the purpose, and when the wire slackens up the lead will
have just touched bottom Apply the brake gradually and heave in.
Take the glass tube out of the container, taking care to keep it vertical,
and apply the tube to the wooden graduated scale from which the depth
in fathoms is read off. Lift the lead on board and examine the arming
and leave everything clear for taking the next sounding.
THE ECHO SOUNDING MACHINE
The Echo Sounding Machine is being rapidly developed and it is
assuredly a most effective aid to navigation The principle is simple
and depends upon the fact that sound travels in water at a known speed
and is reflected from the seabed in the same way that a sound wave m
air is reflected from hills and cliffs.
ECHO SOUNDING MACHINE—ADMIRALTY PATTERN.
Fig. 5.—Recording Apparatus.
The application of the principle in practice calls for ingenuity and
specialised scientific knowledge in adapting electrical apparatus to
recording the very small interval of time taken by a sound wave to
travel down to the bottom of the sea and back again to the ship.
ECHO SOUNDER
133
The apparatus consists of (1) a transmitter fitted inboard to the
bottom of the ship to produce a sound wave under water; (2) a sensitive
receiver of the echo reflec ted from the seabed known as the hydrophone;
(3) recording gear for measuring the interval of time between the sound
impulse and the sound echo. The transmitter and receiver are fitted
on opposite sides of the ship as indicated in Figure 6 and the recording
apparatus is placed on the bridge.
Fig. 6.—The Path of the Sound.
The method of taking soundings is simple. The observer pulls
down the writing table in front of the instrument, thus exposing to
view the depth scale which he turns back till brought up by the stop at
the lower end of the scale. He now switches on the gear by inserting:
134
NICHQLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
the mam switch, situated on the underside of the receiving box ana
puts on the telephone receivers. A faint tapping will be heard but this
is disregarded. He now works his hand wheel, moving up a foot at a
time, until’the tapping suddenly becomes louder, and reads off the depth
directly from the scale. The time taken by the sound wave to travel
to the bottom and back is converted by the recording apparatus into
echo feet or fathoms. Figure 5 shows the recording apparatus with the
door open, and Figure 6 gives a diagrammatic idea of the same apparatus
in a convenient place on the bridge, with the cable leading down to the
transmitter where a hammer is operated by a solenoid; the sound wave
thus set in motion travels to the bottom and up again, the sound being
picked up by the hydrophone and passed on through the return cable to
the head telephone of the observer.
An additional instrument is now being attached to the apparatus,
which produces automatically a trace of the contour of the seabed and
thus exhibits a continuous picture of what the vessel is passing over and
relieves the officer of the duty of listening-in.
THE COMMON LOO
The common log consisted of a reel on which a line, marked off
into equal lengths to represent miniatu^tical miles and called
"knots,” was wound, a log chip and a 1 '< ^ The log
chip was a triangular shaped piece of edge so
that it would float vertical, apex upwai'^^^* ® JPPP ’i jThe l°g hue
was secured to the three comers of the ^ (Ls of a three-
legged bridle. ^ v ‘ 1 • !l ~
The operation of "heaving” the log was as follows. One man held
the reel, another man the sandglass and the officer threw the log chip
into the water and paid out the line. The log chip remained stationary
in the water astern and the ship sailed away from it. When a certain
length of line, called "stray line” to allow the log chip to get clear of
the eddy water in the wake, passed over the rail the officer called out
"turn” and the man turned the glass. As soon as the glass ran out he
called out "stop”; the officer held the line and noted the nearest mark
and so got the speed the ship was going at the time.
The Principle in dividing off the log line was to make the distance
between the knots on the line bear the same proportion to a nautical
mile (6080 feet) as the seconds of the glass bore to the seconds in an
hour (3600).
THE COMMON LOG
m
Example .—Required the length of the knot on the lou line for a
14 second glass.
Knot the glass x 14
Mile an hour ° r 6080 3600
*\ a? knots
6080 X 14
3600
= 23 ft. 7 ins.
About 15 fathoms from the end of the line a piece of white rag was
tucked to indicate the beginning of the marked line, and to know in
heaving when the glass was to be turned. The line was then divided
off into equal lengths of 23 ft. 7 ins. and marked as follows.
To indicate a speed of 1 knot 1 small strip of leather. *
2 knots 2 small strips of leather.
3 „ 3 small strips of leather.
4 „ a piece of cord with 2 knots in it.
5 „ a piece of cord with a single knot.
6 „ a piece of cord with 3 knots in it.
7 ,, a piece of cord with a single knot.
8 ,, a piece of cord with 4 knots in it.
and so on.
A short method of finding the approximate length of a knot was to
add a cypher to the number of seconds run by the glass, and divide by 6.
This gave the number of feet, the remainder multiplied by 2 gave the
inches.
6 )140
23 ft. 4 ins.
The common log is no longer used at sea and we have referred to it
in the past tense, but reference to it is still of historical interest owing
to the fact that the word “knot,” which is a “unit of speed” and not of
distance, is derived from the marks on the hand log line. When, say,
3 knots on the line had run out the seaman knew that the ship’s
speed through the water was 6 nautical miles per hour, and if 4 knots
ran out that she was going 8 nautical m.p.h., hence the query “how
many knots is she going?”
THE PATENT LOG.
There are many different kinds of patent logs now in use, and all
candidates should have some practical knowledge of the use and care
of them.
SPEED RECORDER
137
Walker’s Patent “Cherub” or “Neptune” Tafirail Log is one greatly
used nowadays, and most candidates will have had more or less experi¬
ence in its working. It consists of a cylindrical brass case with a dial,
the case containing the registering machinery.
The dial is marked round its edges from 0 to 100, these figures repre¬
senting miles. A brass hand points to the number of miles run. There
is also a smaller hand, like the seconds hand of a watch, which indicates
the quarter miles. A bell within the brass case is struck as each sixth
part of a mile is recorded, that is, the bell is struck six times during a
run of one mile.
In the latest type of “Cherub” log the small hand indicates tenths
of miles instead of quarters, and the bell is hot fitted.
A rotator is towed by means of a patent log line. This revolves
according to the speed of the ship, and works the mechanism in the
brass case, the distance covered being read from the dial. A “governor”
is attached to the line just abaft the rail; this helps to make the log
work at a uniform speed.
The figures show an electric “Cherub” log fitted to the taffrail and
connected up to a repeater log in the chartroom. A common practice
is to tow the log from a boom amidships as shown in Figure 8, the speed
indicator being in the chartroom or on the bridge.
1. Having “streamed the log,” what attention will you give it while
in use?
See that the line is clear, the governor is acting properly, and that
there is nothing foul of the rotator. Take every opportunity of testing
the accuracy of its readings, not forgetting that it indicates the distance
travelled through the water, not the distance made good over the
ground. Give the mechanism a drop or two of good oil occasionally.
Take care to haul it in before stopping, or when likely to have to go 1
astern on the engines.
2. Does the dial indicate the speed at which the ship is travelling at ■
the time you look at it, or does it only record the number of
miles run?
It only records the number of miles and quarters or tenths of a'
mile which the ship has run.
138 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
3. What length of log line would you pay out ?
The length of line will depend on the freeboard of the vessel and
her speed, more line being paid out when in ballast than when
loaded so that the rotator may be kept well submerged and clear of
eddy water in the wake. The usual length is 40 fathoms at 10 knots,
but for small vessels and slower speeds shorter lengths can be used.
The accuracy of a log may be tested by checking it agamst the
known distance steamed between two fixed points, or by trials on a
measured mile, making due allowance for the effect of tide, if .any.
On measured mile trials the mean of the speeds, not of the times, is
used. If the log registers too low, lengthening the line usually increases
the log registration.
A When a patent log line is hauled in, how do you get the turns out
before drying it and stowing it away?
By paying it out over one quarter as it is hauled in on the other.
When I haul it in from the rotator end, it comes up clear of turns. Where
a clear run of deck is available, by hooking the line on to a swivel and
running along the deck with it, it can be hauled in without any turns
getting in it.
5. What do you do with the part which you unship from the rail before
stowing it away?
Clean it well, both inside and outside. Work some kerosene through
it, and, when you have got it thoroughly clean, some olive oil will
keep it in good condition till you want to use it again. The rotator
should also be cleaned and oiled.
Electrical Ship Logs have been devised to give a continuous record
of the speed through the water and the total distance run by measuring,
either in pressure units or in units of rotation, the flow of the water
passing the ship.
The Chernikeeff Log is ..manufactured by the Electric Submerged
Log Company, London. It records the distance run through the water'
at any speed from practically zero up to 40 knots.
The apparatus consists of a distance recorder (2) fitted in the chart-
room, which registers every 20th part of a mile, the dial being calibrated
up to 10,000 miles. A speed table is fitted below the speed indicator
dial and an electric flash lamp below the table. If the time is taken by a
stop watch between the flashes, the speed can be read direct from the
SPEED OF PROPELLER
139
speed table. A 6-volt dry battery (3) provides the current necessary
to operate tie distance recorder.
Pig. 10.—Clienukeefi Electric Rog,
Tie essential element is an impeller (5) fitted in a horizontal tube
at tie end of a vertical rod which protrudes 10 to 15 inches outside the
bottom of the vessel. This vertical rod passes through a tube (8), which
is flanged and riveted to the shell plating at (7), a sluice valve (6) ensures
watertightness when the impeller rod is drawn inboard by means of its
handle at the top end.
The impeller is rotated by the flow of water passing the ship, the
pitch being such that it makes one revolution for every 1-35 feet of
distance run. The gearing and electrical connections are so arranged
that a contact is made at every 45th revolution of the impeller, that is,
on the completion of every 60-8 feet of distance run. The contact
energises the coil in the distance recorder and each impulse allows
the indicator to move round one division on the dial, each division
representing 60-8 feet of travel or one-hundredth of a nautical mile.
THE SPEED OP THE PROPELLER.
4
approximation of the speed and distance sailed may be computed
from the revolutions of the ship’s propeller, the uncertain factor in the
calculation being the “slip. 3 *
140
jrfICHOLLS’S SEAMANSHIP AND NAt/TICAL KNOWLEDGE
The Pitch of the screw is the distance it would move the ship ahead
in one revolution, supposing there is no slip, or supposing it to revolve
in a solid instead of in water.
The Slip is the difference between the actual speed of the ship and
the speed of the propeller or engine speed. It is due to the yielding of
the water to the pressure exerted on it by the screw as it forces the ship
ahead. The slip is increased when the wind and sea are ahead, also
when the ship’s bottom is foul and her progress through the water
retarded.
The Engine Speed is the rate at which the propeller would drive the
ship if there was no slip.
Example .—Required the speed of a ship, the pitch of propeller
being 18 feet, and making 70 revolutions per minute, no slip.
Speed =f pitch X re vs. X60 minutes -f- ft. in nautical mile
Speed=18 ft. X 70 X 60-6080=12 43 knots
Example .—A propeller has a pitch of 20 feet and makes 65 revs, per
minute. The log registers 10*5 miles in one hour, what is the slip?
Engine speed =pitch xrevs. X 60-f-6080
„ =20 ft. X 65 X 60--6080=12*8 knots
Actual slip=engine speed—speed of ship=12 *8—10*5=2*3 miles
per hour
Slip is usually expressed as a percentage.
Slip per cent. =actual slip X100--engine speed
„ =2*3 X 100-^12-8=18 per cent
FUEL CONSUMPTION AND SPEED,
Equations connecting coal consumption and speed are merely
approximate and have been deduced from experiment and experience
as so much depends upon the quality of the coal, the design and efficiency
of engines and boilers, the trim of the ship and the state of the weather.
Bad steering reduces the speed.
The consumption of coal or oil varies approximately as the “cube
of the speed” and also as the “speed squared multiplied by the distance”
for moderate speeds up to about 14 knots, after which the ratio of
consumption to speed increases very steeply.
I. new consumption new speed 3 _ new displacement*
old consumption old speed 3 old displacement*
II. new consumption _ new speed 2 X new distance
old consumption ~~ old speed 2 X old distance
METEOROLOGICAL INSTRUMENTS
141
Example .—A vessel’s consumption of coal is 30 tons per day at 12
knots, required her consumption at a reduced speed of 10 knots,
new G __ new speed 3 G 10 3
~ ^ 12 3
old C
G =
old speed 3 * 30 ~
30 X 10 X 10 X 10
12 X 12 X 12
= 17 *3 tons
Example —In bad weather a vessel makes 10 knots for 4 days of 24
hours each on 25 tons of coal per day and finds she has 1000 miles to go
and only 80 tons of coal left. Find the reduced speed to enable her to
reach port under the same weather conditions.
Write down the equation, fill m the quantities given in the question
and solve for speed.
new G _ new speed 2 X new distance
old C old speed 2 X old distance
80 tons _speed 2 X 1000 miles
100 tons 10 X 10 X 960 miles
speed 2 = 8 X 96 4-10 = 77
Speed = ^77=8 *8 knots. Reduce to 8*5 knots until the weather
conditions for steaming improve.
Example .—The average speed is 12 knots on 40 tons of coal per day.
After 10 days’ steaming there is 350 tons of coal left and 3000 miles to go.
Required the reduced speed to reach port.
Ans .—11 knots.
THE MARINE BAROMETER—CONSTRUCTION AND
PRINCIPLE.
The barometer consists of a glass tube about 33 inches in length,
closed at one end and filled with mercury. The tube is then inverted
and its lower end immersed in a cistern containing mercury. The
column of mercury remains stationary in the tube at a height corres¬
ponding to the pressure exerted by the atmosphere on the surface of the
mercury in the cistern. The column lengthens when the pressure is
increased and shortens when the pressure is diminished, thus the weight
of the column exactly balances the pressure of the atmosphere. The
height of the top of the column above the surface of the mercury in
the cistern is measured by means of scales graduated in inches or milli¬
bars or both. The space between the mercury and the top of the tube
is called the Torricellian vacuum.
4n analogy exists between the action of a pump and the action of a
142
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
THE MARINE BAROMETER.
Tbrrtceflfen vacuum —
Top or column of mercury -
Graduated Scute
to which The uernter\
is attached —
Screw with
kfcun part of Tube—*■
Capillary Tube .
(Small hare)
Air Trap -
tU milled head for
„ actuating vernier | Hfi
Gmb his -
Attached
Thermometer.\
Bulkhead
Fig 11.
The barometer is an instrument for measuring variations in the weight
or pressure of the atmosphere.
The most important part of it is a glass tube containing mercury. This
tube is airtight at the top and open at the bottom. It is fitted in a case with
its open end immersed in a cistern also containing mercury. The pressure of
the atmosphere on the surface of the mercury in the cistern maintains the
column of mercufy in the tube at a height which corresponds to that pressure.
Readings are obtained by means of a graduated scale and vernier.
The left-hand drawing represents the glass tube taken out of its case so
that the different parts of it can he seen. The other one shows the complete
instrument suspended from a bulkhead by means of an arm and bracket.
METEOROLOGICAL INSTRUMENTS
143
barometer. When the pump is at rest the atmospheric pressure in the
chamber is equal to the pressure on the surface of the water in the well.
When the pump is worked, a partial vacuum is created in the chamber,
thus diminishing the pressure, so that the relatively greater pressure
exerted on the surface of the water in the well raises thp water into
the pump chamber.
In like manner, the pressure having been removed from tiie inside
of the tube of the barometer by expelling the air, the pressure of the
atmosphere on the surface of the mercury in the cistern forces the
mercury up the tube, until the weight of the column is equal to that
pressure.
A water barometer would require a tube about 33 feet in length, but
mercury, being 13J times heavier than water, only requires a tube
about 32 inches in length.
Pumping is the name given to the rising and falling of the mercury
caused by the heaving of the ship at sea, or the rocking of the instrument.
Pumping is reduced by contracting the bore of the tube and also by
slinging the barometer in gimbals.
Certain precautions have to be observed when taking down a
barometer and packing it for transport to protect it from damage.
Unship it from the bracket and handle it carefully. The instrument
should be brought into a horizontal position very gradually in order to
allow the mercury to flow gently to the top of the tube. Put the baro¬
meter in its box and use soft packing, avoid jars and concussion, and
carry the box horizontally with cistern end tilted up slightly. If
sending by post or rail, put the label on the end next to the cistern,
and mark it boldly “scientific instruments—glass—fragile—keep fiat
or this end up.”
If a mercurial barometer were brought quickly from an upright to
a horizontal position the weight of the mercury would probably break
the glass as there is no air at the top of the tube to act as a cushion.
A Millibar js the thousandth part of a “ Bar,” which is the unit
, adopted by meteorologists to express the average pressure of the
atmosphere at sea level and is approximately 14J lbs. per square
inch—1000 millibars=29 *5 inches of mercury.
The Vernier is a sliding scale by which more accurate readings of a
fixed scale may be obtained. The principle of its construction is, that
a given length of vernier, equal to a certain number of divisions of the
fixed scale, is divided into one more or one less than that number of
divisions. The incn vernier of the marine barometer » usually equal
144:
NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
in length to 9 divisions of the fixed scale and divided into 10 equal parts,
the degree of accuracy thus obtained being *005 of an inch.
The millibar vernier is equal to 39 divisions of the fixed scale, but
instead of being divided into 40 parts, the vernier is divided into 10
equal parts, thus giving a wider spacing of the divisions making it
easier to read without loss of accuracy, the nearest reading obtainable
being one-tenth of a millibar.
12 -—Barometer Inch Scale and Vernier. The Reading is 29*684,
The figure illustrates a barometer scale and vernier graduated in
inches. AB is the fixed scale, CD the sliding vernier, D is the top of
the mercury column. The reading is 29*684 arrived at as follows:
The point D Ees between 29-650 and 29-700, the lower reading is
noted, 29*65 and the additional part is got from the vernier. The
METEOROLOGICAL INSTRUMENTS
145
spacing on the fixed scale is *05 of an inch, and this is divided into five
equal parts by means of the enlarged divisions numbered 1, 2, 3, 4, 5
on the vernier; these parts, however, are really -01, *02, *03, *04, *05,
the *0 being left out for convenience. Run the eye up the vernier until
one of its divisions is exactly coincident with any division of the fixed
scale. It is the second one above 3 which is -034 to add to 29 *650 making
the reading 29*684. The short divisions between the numbered ones
on the vernier are in succession *002, *004, -006, *008 of an inch.
Fig. 13.—Millibar Scale and Vernier. The Reading is 1012-7 mb.
Figure 13 shows part of a millibar scale. AB is the fixed scale
from 990 mb., to 1060 mb. CD is the sliding vernier, D is the top of
the mercury column. The reading is 1012*7 millibars. The millibars
are read from the AB scale and the decimal from the CD scale.
Instrumental Corrections for Latitude, temperature and height above
sea level are necessary in order to reduce the observation to a common
standard for the purpose of comparison with the readings got from
other barometers.
The standard Latitude is 45°, this correction is necessary because the
force of gravity is greater at the poles than at the equator, due to the
polar diameter of the earth being shorter than the equatorial diameter.
146 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
The standard height is sea level, the correction being about one-
fcenth of an inch for every hundred feet, and is due to the atmospheric
pressure decreasing with the height.
The standard temperature is 32° Fahr ; this correction is necessary
because the column of mercury lengthens and shortens with heat and cold.
The value of these several corrections may be found m the Barometer
Manual.
Errors of Capillarity and Capacity.—Capillarity is due to the surface
tension of the mercury and the frictional resistance between the mercury
and the glass tube. It depresses the level of the mercury.
Capacity is due to the changes in the level of the mercury in the
cistern as it rises and falls in the tube.
The scale of marine barometers is graduated to obviate the necessity
of applying these two corrections, the mercury inches being shorter
than lineal inches.
An Aneroid Barometer consists of a circular metallic chamber
partially exhausted of air and hermetically sealed. Variations in the
pressure of the atmosphere produce changes in the volume of the
chamber, and by an arrangement of levers and springs the motion thus
imparted to the chamber is communicated to a hand which indicates
the prevailing pressure.
It is not so reliable as the mercurial barometer, with which it should
be frequently compared, nor is it possible to find with sufficient accuracy
for scientific purposes the index error of the aneroid.
Aneroid readings require correction for height above sea level and
index error, but not for tetnperature or latitude.
An aneroid is popular on board ship because it is very handy and
also more sensitive to small changes of pressure than the mercury
barometer. Space often being an important consideration, it can be
hung in positions which would be impossible for a mercury barometer.
Having no vernier to adjust, readings are quickly and easily obtained.
Being used principally to indicate changes of pressure as an aid to
forecasting the weather, it is not customary to apply any corrections to
its reading.
A Barograph is a self-recording aneroid. It consists of a series of
vacuum metal boxes with elastic lids. The volume of the boxes changes
with every variation of pressure in the same way as in the aneroid
barometer. The expansion and contraction thus caused are communi¬
cated through a lever to a pen, which marks an inlr trace on a paper.
This paper is wound round a drum, which is rotated., on a vertical axis
METEOROLOGICAL INSTRUMENTS
3
by means of clock work, making a complete revolution in seven da
The vertical lines printed on the barograph chart represent time, a
the horizontal lines either inches or millibars- The pen moves up a
down in response to changes of pressure* and the revolving dri
imparts a horizontal motion to the paper which slips round under the p«
Fig 14.—A Barograph
The chief advantage lies in the fact that a continuous record c
changes in pressure is presented in a graphic form, by means of whic
the history of the barometrical changes may be read at a glance, eve
slight fluctuations of pressure due to passing squalls being recorded.
Barograph readings are subject to the same corrections as th
aneroid, in addition to regulating its time at sea. The drum rotates a
a uniform rate, while the ship time changes as she sails East or West
the drum should therefore be set to G.M.T. and the ship’s Longitude
noted on the barograph chart.
THE THERMOMETER.
Construction and Principle.—It consists of a glass tube of very
small bore, having a bulb attached to one end, sealed at the other, and
partially filled with mercury, or with spirits of wine if the instrument
is required for very low temperatures.
Bodies expand with heat and contract with cold, and as mercury
expands to a greater degree than glass we find the thin thread of mercury
rising and falling in the tube as the temperature increases and decreases
respectively*
The two fixed points of the scales used in making thermometers
are 'the freezing point and boiling point of distilled water, when the
barometrical pressure is 30*0 inch
148
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
The space between these two points is divided into equal parts cal
degrees; the following systems of graduating have been adopted.
Fahrenheit
Centigrade
Absolute.
R6aumui
Boiling point - -
212°
100°
373°A
80°
Freezing point- -
32"
0°
273°A
0®
The spacing of the degrees in the Absolute
scale is the same as in the Centigrade, but there
are no minus readings with the former.
The real reason why Fahrenheit fixed the
zero of his scale as 32 degrees below the freez¬
ing point of water seems to be lost in the mists
of obscurity, but the zero of the Absolute scale
is based on the doctrine that gases contract on
being cooled, their volume being diminished
with loss of temperature. The zero represents
the temperature at which a gas would have no
volume, it would then cease to exert pressure,
or be capable of developing energy.
The figure represents a portion of a ther¬
mometer showing the Absolute scale to the left
side of the thread of mercury and the Fahrenheit
scale to the right. The space between freezing
point and boiling point is divided into 100 parts,
0 to 100, in the Centigrade scale; and 180 parts,
32 to 212, in the Fahrenheit scale, so that
100° C. is equal to 180° F. It is sometimes
required to convert one reading into the other
which may be done as follows by assuming that
Fahrenheit called the freezing temperature of
water 0 as he might have done.
Example .—Convert 310° Abs. into the cor¬
responding Fahr. reading.
310 Absolute—273=37 Centigrade
Fahr. reading Cent, reading
Fahr. range Cent, raifge
_ 37 ^ _ 37 X 180 333
180 100 " * ~ 100 “ T
= 66-6 + 32 = 98*6 Am.
•10
300
■»
8 <
■7<
%$o-
230
6
5
4
260 —
2
t
Fig 15—Fahrenheit a
Absolute Scales.
METEOROLOGIGAL INSTRUMENTS
u
We add 32° to get the Fahr. reading, 98*6, because in the calcuiatio
we assumed freezing point to be 0 instead of 32°.
Example .—Convert 60° Fahr. into the corresponding Absolute seal
reading.
Assume freezing point Fahr. to be zero then 60—32=28.
Cent, reading Fahr. reading — 32
Cent, range Fahr. range
* _ 28 ^ _ 28 X 100
100-180 ‘ * 180
140
= 15*5
C
+273-0
Ans. 288*5 Abs.
Check those answers by referring to Figure 15.
THE MAXIMUM THERMOMETER.
The maximum thermometer is designed to record the highes
temperature experienced during a given period. The tube is reduce*
in bore about an inch from the bulb. The thermometer is hung nearh
Fig. 16.
horizontally with the bulb end slightly lower than the other. Aj
the temperature rises the mercury expands and is forced past* th<
constriction, but, when a subsequent fall of temperature causes i
contraction of the mercury, the thread breaks at the constriction s<
that its upper end remains in position and registers the highest tempera
150 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
fcure reached. To reset the thermometer, hold it vertically, bulb dowi
shake gently and the thread of mercury will reunite with the mercur
in the bulb.
THE MINIMUM THERMOMETER.
The minimum thermometer records the lowest reading experience
in a given interval The most common type is a spirit thermomete
having a small index immersed in the spirit in the stem. It is als
Fig. 17.—Hygrometer.
hung horizontally. As the temperature falls the index is carried
towards the bulb by the spirit, but if the spirit subsequently expands,
in consequence of a rise of temperature, it flows past the index, which is
left in position to indicate the lowest temperature reached. To reset
this thermometer, hold it vertically, bulb up, tap it gently and the
index will find its way back to the end of the thread of spirit. (Fig. 16),
The Thermograph is a self-recording thermometer, which gives a
METEOROLOGICAL INSTRUMENTS
15 !
continuous record of temperature. The thermometer consists of a
slightly curved metal tube filled with spirit, one end of the tube being
fixed rigidly to the instrument, and the other end attached to the
system of levers which actuates the recording pen.
The great advantage of the thermograph, especially if studied in
connection with a barograph, is to demonstrate the close relationship
which exists between the fluctuations of temperature and pressure.
Thermographs must be exposed out of doors and consequently the
bearings require to be frequently oiled and examined. The instrument
takes an appreciable time to alter in temperature, so it is apt to be
sluggish when the changes of temperature are rapid.
MASON’S HYGROMETER
It consists of two ordinary thermometers placed side by side. One,
called the wet bulb, has a piece of cambric tied to the bulb, and a few
strands of cotton wick fastened to the cambric with their lower ends
dipping into a cup of water. The cambric is thus kept moist. The
thermometers should be mounted in an open screen through which the
air passes freely, and away from the effects of heated currents of aii
from cabins, etc.
Care should be taken to keep the cambric and wick clean, and the
cup replenished with a supply of fresh water. Should the cambric and
wick get wet with salt spray, they should be cleaned in fresh water, and
care should be taken that no water is adhering to the dry bulb when
the readings are noted.
The hygrometer measures the humidity of the air. When the air
is dry, evaporation takes place and the water dries off the cambric,
thus reducing the temperature of the wet bulb thermometer; when
the air is moist there is less evaporation so that the difference between
the wet and dry bulb readings is correspondingly less.
Consequently, in damp weather or when the air is saturated, there is
little or no difference in the readings, but in dry weather at sea the
wet bulb may be as much as 10° lower than the dry bulb (Fig. 17).
A RAIN GAUGE
This instrument is not usually included in the weather recording
apparatus supplied to ships, but if it were carried it would be hoisted
to a suitable height above the deck where it would be free from the
sheltering effects of deckhouses, etc., also from sprays
152
NICHQLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
It consists of an open mouthed canister 5 inches in diameter as in the
figure. The raindrops fall into the can and pass through the funnel
into the jug. The rain water is poured from the jug into the measuring
Fig 18.—Rain Gauge.
glass, which is scaled o£E into hundredths of an inch of rainfall. One
inch of rain caught in the rain gauge represents a rainfall of 101 tons
per acre, or its equivalent volume of 3630 cubic feet of water.
RADIO DIRECTION FINDER
Directional wireless as an aid to navigation is a usual part of the
equipment of a well found ship. Figure 19 illustrates the apparatus
supplied by the Radio Communication Company, London. The frame,
or loop aerial on the bridge is rotated by means of the handwheel
fitted to the lower end of the vertical spindle, which extends down from
the aerial through the deck to the chartroom below. The frame aerial
when rotated picks up the wireless wave, the signal strength reaching
its loudest when the plane of the frame aerial is parallel to the incoming
signal, that is, when it is edge-on to the direction of the station from
whence it is being transmitted.
The position of maximum strength is not sharply defined, but on
rotating the frame the signal strength gradually drops to inaudibility
when the frame is facing the direction of the station. A well
defined “silence arc” of a few degrees on each side of the required
direction is established and by rotating the frame either way the signal
again rises to audibility. It is then a simple matter to observe by the
RADIO DIRECTION TINDER
153
Fig. 19.—Radio Direction Finder.
Pillar of aerial through bridge deck into chartroom and operated by hand*
wheel on its lower end.
154
NICHOLAS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
pointer on tlie scale of degrees tlie two points limiting the arc of silence
and the mid-point between which gives the required direction but, in
the first instance, the direction is relative to the ship’s head only. The
actual direction of the ship’s head by compass should be taken at the
same time as the wireless observation to enable the true bearing of the
distant station to be obtained.
Example .—The radio direction finder records a bearing 120°, ship’s
head 030°. Required the true bearing of the station.
Direction of ship’s head. 030°
Radio angle between ship’s head and station - - 120
True bearing of station - * * - S. 30° E or 150
The magnetic field of the ship interferes with the normal direction
of the incoming wireless wave, consequently the apparent direction of
the distant wireless station is altered. The errors caused are quadrantal,
that is to say, they reach a maximum value every 90°, or four maxima
and four minima in a complete swing. In a ship having perfect electrical
symmetry the induced currents in the structure produce a magnetic
field in the athwartship line and the quadrantal error is zero in directions
0°, 90°, 180°, and 270° from the bow, the maximum error appearing
at 45° on port and starboard bows and on port and starboard quarters.
In most cases, however, the ship’s magnetic field is unsymmetrical so
that the quadrantal error is zero at four other angles from the bow, but
the maximum errors are still separated by 90°. The apparatus is
provided with permanent correction adjustment so that the correct
angle between the ship’s head and the station may be read direct from
the scale. There are other types of wireless directional indicators known
as radio beacons for transmitting wireless fog signals as described under
Notices to Mariners, page '248.
SLUICES AND WATERTIGHT DOORS.
A sluice valve is a watertight vertically sliding shutter over a hole
cut in the lower edge of a bulkhead to allow water to flow from one
compartment to the next. The valve is raised and lowered by means
of a rod secured to it and operated by hand from an upper deck above
the waterline. The fewer sluices fitted in a ship the better. None
is fitted in the collision bulkhead nor at any other watertight bulkhead
unless arranged so as to be at all times accessible. They should be
WATERTIGHT BULKHEAD DOORS j.55
kept closed at sea and opened and closed frequently to keep them in
working order.
But large passenger vessels are divided into numerous compartments
by transverse and longitudinal bulkheads, and it is necessary to provide
means for passengers and crew to move freely through the intervening
u lea s. Large openings have therefore to be made below the water-
Fig. 20.—Watertight Doors. Control Apparatus in Wheeihouse.
line in some of the bulkheads, and in order that these may be closed and
-made watertight at a moment’s notice the Stone System of hydraulic
control for bunker and other sliding bulkhead doors is fitted.
The control apparatus is fitted on the bridge. Figure 20 shows
the bridge control and indicator. The officer on a suc[den emergency
call turns the valve control handwheel, and immediately a pre-warning
156
NIOHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
signal bell is given at each door, then all doors connected to the system
are closed by means of hydraulic rams; and, on the doors reaching their
closed positions, glass discs are illuminated in the electrical indicator
mounted over the control, thus indicating that the operation has been
effected. By reversing the control valve handwheel the doors may be
opened again. Each door when closed may be opened by any person
wishing to pass through by merely pressing a lever, but immediately
the lever is released the door automatically closes again.
TYPICAL ARRANGEMENT OF
HORIZONTAL SLIDING **STONE“ WATERTIGHT DOOR.
* Fig. 21.
An identification disc is provided for each door showing by
its illumination on the indicator in the wheelhouse whether it is closed
or open and its particular position in the ship.
The above figure shows a typical arrangement of a horizontal
sliding watertight door. The pumping machinery to maintain a con¬
stant pressure of water to operate the hydraulic rams is installed in
the engine-room.
STEERING GEARS
157
STEERING GEARS
The simplest form of lever for turning a rudder is the “helm,” now
known as the “tiller” in small boats. A wheel and axle purchase is
substituted m small ships in order to
get more power to turn the heavier
rudder. It is simply a rope with its
middle part wound round a barrel and
the ends led through leading blocks at
the side of the deck and made fast to the
end of the tiller. The steering wheel is on
the end of the barrel and when the wheel
is turned the barrel with the rope on it is
turned also and the rope pulls the tiller to
one side or the other.
The figure shows a type of screw steering
gear fitted in larger vessels A crosshead A
is keyed firmly to the rudder head B , the
crosshead is equivalent to the tiller because
when it is turned the rudder post turns.
0 and C are the port and starboard rods,
the port rod has one end bolted to the
crosshead at A and the other end to a
sleeve D 1 . The starboard rod is similarly
connected to the crosshead and to the sleeve
D 2 . The sleeves D 1 and D 2 work, respec¬
tively, in right and left-handed screws cut
on the common shaft F, which is turned by
the steering wheel, so that the sleeves
move in opposite directions and turn the
crosshead.
The Requirements of a steering gear are,
to move the rudder to any position with as
little delay as possible; to hold the rudder
in position under the stresses imposed in
manoeuvring the ship; to give way before
any abnormal stress such as caused by a
wuve, and automatically to return to its
former position; to be absolutely reliable.
Usually eight turns of the steam steering
wheel are required to put the rudder from
Fig. 22.—Principle of the
Screw Steering Gear.
A. The crosshead (equivalent
of tiller).
B. Rudder head.
C. Connecting rods.
D. Sleeves working on guide
rods E.
D x - Gears with right handed
thread and B* with left
handed thread, both
threads being cut on
shaft F, which is oper¬
ated in either direction
by hand wheel or engine.
158
NIOHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
hard over on. one side to hard over on the other and at least double
that number of turns for hand steering gear.
Fig. 23. Poop fittings of Caledonian Monarch .
Note. Steering chains, spring buffers and the rudder brake on quadrant.
See also page 610.
fhepriaciple of the rudder has not altered with the march of progress
but the method of controlling it has to be modified to work the heUiu
STEERING GEARS
159
rudders of the bigger ships. The tiller, or crosshead, or quadrant
fitted on the rudder head is now turned by a steam engine. The man
operating the steering wheel merely opens and closes a valve which
admits steam into the engine Wheel chains are shackled on each side
of the quadrant as shown in the plan of the poop of Caledonian Monarch,
and led along their respective sides of the ship to the drum of the steering
engine. The engine turns the drum, the drum coils up the chain on
one side and uncoils the chain on the other side and go heaves the
quadrant round.
Fig. 24.—Steam Steering Engine Geared Direct to Quadrant.
The Steering Engine may be installed on the bridge but this requires
a long length of shafting, spring buffers and chains to connect up with
the quadrant, so it is usually placed in the engine-room of ships of moder¬
ate size and invariably the engine is geared direct to the quadrant in
large vessels. The engine in such cases is operated by the turning of a
rod, set in motion by the steering wheel, and which is led downwards
and along through various compartments, the continuity of action being
maintained by bevelled gearing at the points where the direction of the
rod is diverted. These long leads with the bearings, bevelled whpel
and sliding joints, absorb a large amount of power in overcoming
160 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
frictional resistance, in addition to being noisy where the rods pass
through living quarters. In place of rods and chains we now have the
valve of the steering engine opened by a lever as before, but the
movement of the lever is controlled by hydraulic pressure.
Fig. 2S,—Steering Telemotor.
TELEMOTOR STEERING GEAR
161
TELEMOTOR STEERING GEAR
The apparatus consists of a steering telemotor on the bridge, a
motor telemotor at the engine geared to the quadrant and two copper
pipes of small diameter connecting the two gears, the whole system
being charged with a special non-freezing liquid.
There are two cylinders with pistons fitted at the steering end and
two similar cylinders with pistons at the engine end, the pistons or
rams in the'Corresponding cylinders, port and starboard, being operated
by the liquid in the connecting pipes on the principle that liquids
are incompressible. The piston ram aft operates the connecting rods
and levers, which open and close the steam valves of the engine
Fig 26 —Transverse Section through Steering Telemotor.
Figure 25 illustrates the Mactaggart-Seott Safety Steering Telemotor.
Note: —(1) The tell-tale pointer or helm indicator at the upper sector and
the two copper pipes leading down through the deck towards the motor
telemotor. (2) The pressure gauges to indicate the liquid pressures in
each pipe line* Equality of pressure is essential and in this system it
162 NICHOLLS’S SEAMANSvHIP AND NAUTICAL KNOWLEDGE
is made by putting the helm amidships and raising the hand lever at
the side. The liquid throughout the system is then brought into free
communication by means of a bye-pass valve and the pressure automati¬
cally equalises itself. (3) The cylinders are vertical as shown by the
transverse section (Figure 26). The motion of the steering wheel shaft is
transmitted by a rack and pinion gear to the rams, causing the
latter to move up and down in the cylinder according to the
direction in which the hand wheel is turned from the amidships position.
In the diagram of the pipe system connecting the steering telemotor
to the motor telemotor the arrows indicate the circulation of the oil
from the charging tank and back again when charging and testing the
pipe line.
To Replenish the System.—
1. Disconnect pipes B and G at the steering wheel and connect
temporarily the spare part BO, called the wash-out piece.
2. Fill the charging tank with the hydraulic oil which forms a
gravity feed to the hand pump.
3. Disconnect pipe A at valve D, put the end of the pipe into a
bucket, work the pump and pass some oil through the pipe. The flow
being satisfactory connect up pipe A again.
A. Open charging valves D and E, also liquid saving valves F and G.
Disconnect pipe 0 at valve G and put a bucket under the end of it.
Continue pumping. The oil will then flow from the pump through the
pipes A, B and 0 in succession and pass into the bucket. Keep pumping
for a little time to get a steady flow of oil, thus proving that the pipe line
is quite clear. Keep pouring oil into the charging tank at intervals
to ensure that air is not being pumped into the pipes.
5. Disconnect pipes BG from the wash-out piece and connect to the
steering telemotor.
To Charge the System.—
The Steering Telemotor.— Put the wheel amidships and open the
by-pass by raising the hand lever. Open valve J. ’Pump until the oil
rises in the replenishing tank to the level mark on the gauge glass. Close
valve J . Release air at air cocks on the pressure gauge pipes.
The Motor Telemotor —Release air at air cocks K on the motor
cylinders and continue pumping until for each stroke of the pump a
rush of liquid comes from the return pipe H. Close charging valve B,
then charging valve D. Open valve J at the steering telemotor (this
valve should only be closed when charging the system). Release the
safety by-pass hand lever. The telemotor is now ready for working*
TELEMOTOR STEERING GEAR
161
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Emergency Steering Gear.—A method of steering the ship alternative
to the steam engine gear has to be provided. This sometimes takes the
form of hand screw gear, as already described, mounted over the rudder
head and geared into the crosshead by dropping in bolts. It is impracti¬
cable to steer large vessels satisfactorily by hand gear, so usually two
steering tackles are kept ready at hand, one for each side. One block
of the tackle is shackled to the end of the quaclrant and the other block to
a ringbolt directly forward of it, the hauling part being led to the barrel
of a winch in substitution of the steering chains. Eefer to the poop
plan of Caledonian Monarch and note the rudder brake on the after
side of the quadrant to hold it in position in the event of a breakdown,
also that the small inner barrels of the shaft of the winch are intended
for the hauling part of the steering tackles (Fig. 23).
Fig 28.—-Steam Capstan.
The chief officer is responsible for the working of deck machinery,
but repairs and maintenance are carried out by the engine-room staff.
Steam winches are primarily for handling cargo and incidentally for
warping the ship alongside piers. They may be either spur-geared or
friction-geared, the latter type being designed for quick operating.
The Clutch Winch is employed for quick lowering/ The gear wheel
is driven by a pinion clutched to the crankshaft, and when the load
is raised to the desired height the winch is stopped, the strap brake
applied to the drum and the clutch thrown out of gear thus putting the
load, when being lowered, under the control of the brake.
The Link Motion Gear is usually adopted for cargo winches* The
load is lowered by putting the winch into reverse gear so that the load
DECK MACHINERY
Fig. 30.—Windlass After Side.
Steam Capstan-Figure 28 illustrates a capstan driven bv a ste*™
engine under the deck and controlled from above Tie «JL
pietonis communicated by tie piston rod and crankshaft! theeccelnt
and this rotates the horizontal shaft which engages by spur and btel
im
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
gearing with the lower end of the capstan spindle projecting below the
deck but not shown in figure. The direction of motion and the stopping
and starting of the engine are regulated by turning the vertical
rod, which has a thread cut on its lower end to engage with the short
horizontal lever operating the steam valves. This engine may be
disconnected for warping by hand capstan bars.
The illustrations show the fore part and after part of an Emerson
Walker Patent Quick Warping Direct Grip Windlass (Figs. 29 and 30).
Before starting any deck engine, all drain cocks must be opened
and steam allowed to blow through the cylinders until they are clear of
water. When winches are not in use during frosty weather they must
either be kept running slowly or the steam pipes and cylinders freed
from water.
Hydraulic cranes and electric winches are fitted in some passenger
ships as they are cleaner and less noisy than steam winches.
PROPELLING MACHINERY.
Steam propelling machinery consists of boiler, engine, condenser
with auxiliary machines and fittings.
Boilers are of two types, the Scotch or fire-tube boiler in which the
fire passes through tubes surrounded by water, and the water-tube
HC
167
PROPELLING MACHINERY
boiler in which the water circulates
fire and hot gases. Merchant ships
boilers, installations of water-tube
warships.
inside tubes surrounded by the
are usually fitted with Scotch
boilers only being common in
Fig. 31a-
■Single Ended Scotch Boiler (in section) without Mountings,
A Shell Plate.
B Top Manhole 16"x 12".
C End Plate.
B Combustion Chamber Girders and
Stays.
E Combustion Chamber Wrapper
Plate.
F Combustion Chamber Back Plate.
G Combustion Chamber.
H Combustion Chamber Stays.
/ Back Tube Plate.
K Combustion Chamber Bottom Plate.
L Bridge
M Back Bearer.
A 7 Firebars.
O Centre Furnace.
P Bottom Manhole 15"x 11".
Q Stay.
R Stay.
•S Front Tube Plate.
T Plain Tubes
U Stay Tubes.
V Stay Tubes with Nuts,
W Longitudinal Jomt Double Butt
Strap.
X End Plate
Plate
Note. Tubes and Girders omitted on Wing Combustion Chamber for simplicity.
168
NICHOLLS’S SEAMANSHIP AN3>"NAUTICAL KNOWLEDGE
The ordinary marine boiler is said to want less overhauling and
repairing than a water-tube boiler, and is better for cargo and passenger
steamers and general hard work. It does not require such skilled
firing or such constant attention when under steam. The advantages
of a water-tube boiler are that it is suitable for higher pressures (often 300
lbs. to the square inch); it is of less weight for the same power; it carries
less water; and steam can be raised much quicker, in one hour if necessary.
The'heat is generated in the furnace, the top or crown being corru¬
gated to increase the area of heating surface. The heat then passes up
the back end, through the boiler tubes and out through the uptake over
the furnace doors, the smoke and flue gases passing up the funnel
where the temperature may be as much as 600° Fahr. The heating
of the funnel causes it to expand so that the funnel guys must be eased
up if they become too tight. Sometimes the guys are fitted with springs
that require no attention, but when the guys are set up with lanyards
to eyebolts on deck care must be taken that they are maintained at
a suitable tension. ,
Reciprocating Engines may be compound, triple or quadruple
expansion, the steam passing successively through 2, 3 and 4 cylinders
and doing work in each cylinder before exhausting into the condenser.
Turbine Engines are greatly used in warships, and in some passenger
vessels. It consists of a cylinder lying in a horizontal position through
which the propeller shaft passes. A rotor is secured on the shaft. This
rotor is covered with small blades. Steam is admitted which turns the
rotor and shafting and consequently the propeller. -It revolves at a
high speed, and can only turn one way. Another turbine is fitted on
the same shaft for going astern.
Figure 32 illustrates a type of reciprocating compound surface
condensing marine engine suitable for small ships. A is the engine
stop valve, B the valve lever, C the reversing lever which operates,
Z> the links and reversing gear, E are connecting rods connected to the
lower end of the piston rods and to the crank shaft, F is a rocking shaft
to work the air, feed and bilge pumps at H, Gr is the discharge pipe
from the condenser and I is a manhole door on the end of the condenser*
J are relief valves on the low pressure and high pressure cylinders,
L the crank shaft to be coupled to the thrust shaft.
Figure 33 is a diagram to indicate the circulation of the
steam. The working pressure in a marine boiler varies with the type
and ranges between 160 and 220 lbs. to the square inch. The steam
passes through the boiler stop valve, then through the engine stop valve
PROPELLING MACHINERY
169
and then, in succession, through the high pressure piston valve and high
pressure cylinder, intermediate pressure slide valve and intermediate
cylinder, low pressure slide valve and low pressure cylinder, doing work
on the piston of each cylinder as it expands. The slide valves admit
steam alternately above and below the piston. The steam then passes
Fig. 32.—Reciprocating Compound Engine*
into the condenser where it is condensed by coming into contact with
pipes through which cold sea water is being circulated* The air pump
extracts air and water from the condenser and passes the water into a
feed tank and from thence it is pumped back into the boiler.
The sea water runs into the condenser through an injection pipe low .
down on the bilge, tbe circulation being maintained by a circulating
Fig. 34 —Cylinders of a Triple Expansion Engine.
A Motorship is one fitted with internal combustion engines which
work on crude oil. There are no boilers connected with it and no
steam. A donkey boiler is, however, carried on motor ships to supply
steam for winches, heating, etc. Several advantages are claimed for the
internal combustion engine over the steam engine of similar power, viz.,
less space occupied,, the weight of the whole plant is much less than a
steam engine and boilers, the weight of the liquid fuel carried is less than
the coal for the toilers, more cargo can be carried, working expenses are
less as there are no boilers or stokers, fewer hands are required to attend
to the machinery.
The steamship, however, is more reliable and in some respects is
more suitable for certain trades than the motorship. Diesel engines,
are peculiar in that they can only be started by compressed air and
several revolutions are necessary before they become oil fired. This limits,
somewhat, the number of startings of the engine when manoeuvring
in harbours, and the Board of Trade insist that the capacity of the air
receivers should admit of at least 12 consecutive startings of the main
engines without replenishment from the compressors.
1T2
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
FIRE.
1. What precautions are usually adopted to prevent fire on board ship ?
Smoking in the holds during the loading and discharging of cargo or
indeed at any time when there is inflammable material in any compart¬
ment should be rigorously prohibited. A match or lighted cigarette
carelessly thrown away may smoulder for days before bursting into
flame. Wire guards of close mesh placed in ventilator cowls are a
safety precaution against the thoughtless action of smokers.
The human sense of smell is utilised with suspicion when passing*
ventilators and openings leading into holds and peaks, and if there be
the slightest indication of smoke or heat emerging from an opening an
investigation should at once be made.
Regulations and byelaws relating to the prevention of fire are issued
at most ports and rigorously enforced by the authorities, the person in
charge of the ship being liable to a heavy fine should the rules not be
complied with. Stringent rules are laid down when the cargo is of a
highly inflammable nature such as cotton, flax, wool, oil, etc., which
may ignite by spontaneous combustion, all persons on board being .
prohibited from carrying matches, petrol lighters or any apphance for
producing ignition, and very often when no inflammable goods are
being handled only safety matches are permitted.
Persons engaged loading or discharging explosives must wear
rubber boots, and the coamings of hatches, gangways and rails are
specially protected with matting and wood so that the packages may
not knock against a hard surface.
Storerooms in which paint and anti-fouling compositions are stowed
should be well ventilated and no one should enter these spaces with
naked lights. The same precautions should be taken in cargo spaces
especially where coal or oil is, or has been, carried. The ship’s electric
wiring is insulated and led through pipes or protected by casing.
2. What arrangements are made to cope with an outbreak of fire on
board ship at sea?
The provision made in cargo steamships is the usual deck water ’
circulation with the hose coupled up in lengths and connected to the
hydrants on water pipes, with at least 12 fire buckets and occasionally
some portable chemical fire extinguishers placed in convenient positions.
The Board of Trade has issued instructions regarding the proper v
provision of fire extinguishing appliances. These recommendations $
FIRE EXTINGUISHERS
173
have been adopted by the International Convention for the Safety of
Life at Sea, and are to take effect when ratified.
3. Describe how steam is injected into a hold in the event of fire.
Forcing steam into the hold will keep dow*n combustion if it does not
actually put out the fire. The ends of suitable pipes are coupled to
the winch steam pipes on deck, the other ends being inserted into the
hold either by way of the ventilators, or the hold sounding pipes which
should have holes perforated in their lower ends, or through holes cut
in the hatches or deck as near to the seat of the fire as possible. All
hatches and openings into the compartment must be covered to prevent
any oxygenised air getting in. The pressure and the volume of steam
admitted into the hold should be capable of forcing its way into the air
spaces and escaping through any crevices or leakages in the walls of
the compartment, thus preventing the admission of air. The tempera¬
ture of the hold will, of course, rise as evidenced by the heating of decks
and bulkheads, but the object is to keep the fire from bursting into flame,
and cases are on record where this method has kept the fire smouldering
slowly for days and weeks until the ship arrived in port and only on
opening the hatches has the fire become active. In some cases the fire
has been put out, the charred remains of packages in the hold testifying
to the effectiveness of steam in absorbing the oxygen in the hold.
4. Describe some types of fire extinguishers.
Portable Chemical Fire Extinguishers are universally known. They
are manufactured to approved specifications and have a capacity up to
3 gallons as that is the largest size that can be handled usefully by one
man. The liquid in the cylinder is contained under pressure, about
200 lbs. per square inch, and squirts out when the valve is opened. The
charge may be (1) a solution of sodium bicarbonate or potassium carbon¬
ate and a jar or bottle containing either sulphuric or hydrochloric acid;
(2) a capsule of compressed carbon dioxide, C0 2 , of sufficient quantity
to make the fresh water in the cylinder an effective chemical extinguisher
and to exert sufficient pressure to be able to eject the whole fluid a
distance of 20 to 30 feet for a period of not less than 60 seconds.
« Firefoam ” is another extinguishing medium which is specially
effective in the case of oil fire originating in engine and boiler spaces or in
tanks. Oil, in quantity, bums on the surface of water so that a solid jet
of water from a nozzle when turned on the flames merely causes
174
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
the burning oil to spread by washing it into corners or into adjacent
compartments, hence the reason for spraying the water on an oil fire.
Firefoam is contained in portable cylinders, and when discharged
at the spot it froths, spreads, envelops the surfaces, smothers the flames
it comes in contact with and prevents the ignited oil from overflowing
into other compartments.
Fixed Fire Extinguishing Systems usually consist of a battery of
cylinders filled with carbon dioxide gas (C0 2 ) at a pressure round about
900 lbs. to the square inch. A system of pipes leads from the
cylinders to the various compartments and cargo spaces, by way of the
wheelhouse as a rule, where a detecting cabinet is fitted.
In the Lux-Rich system a partial vacuum is maintained in the
chamber of the cabinet by a small exhauster, the suction of which
continuously draws ail samples from all compartments of the ship,
one pipe being fitted for each cargo space. Smoke, drawn from a
tube in the detecting cabinet, is the warning that tells of the existence
of fire in a particular compartment, and a lighting arrangement makes
the slightest amount of smoke strikingly visible to anyone in the wheel-
house, a further warning being given by the smell of the exhaust air
flowing from the vacuum chamber.
When fire is detected the extinguishing gas from the cylinders is
introduced into the detection pipe by means of a three-way valve. The
valve shuts ofl the air flowing up from the cargo spaces to the detec¬
tor and connects the holds with the carbon dioxide which flows direct
from the cylinders along the same pipe, the gas on emerging from the
pipe into the hold expands rapidly and penetrates into crevices and the
inaccessible places, thus flooding the burning compartment with the
released gas and smothering the flames or smouldering mass.
In both the Clayton and the Harper systems the gas is pumped
into the cargo spaces and these systems may also be used for fumigating
the ship.
5. What would you do in the event of fire breakingout, the ship being
at sea?
Give the particular alarm signal as recognised on board the ship,
usually a succession of 6 short blasts followed by 1 long blast on the
whistle. Treat the fire as a serious one from the very first. All fires,
like human beings, begin in a small way. Try to locate the source of
the fire; hands to stations and couple up the hoses.
If the fire can be got at and is found to be small, turn on a fire
FIRE APPLIANCES
175
extinguisher, but if it is too big for that I would turn on the water and
drown it out. Should, however, it be a deep seated fire and inaccessible,
I would close all ventilators and openings into the cargo space and inject
steam into the hold. Ships fitted with refrigerating plant usually
carry cylinders of 00 2 gas. I would inject a few cylinders of this gas
into the hold, introducing it through holes in the bulkheads. Should
£he ship be fitted with a special fire smothering system I would turn it
on to the affected hold immediately the fire was discovered, making sure
that all persons were out of the compartment before doing so.
If the fire were a serious one and had got out of hand, threatening
danger of a conflagration or explosion, I would swing out the boats and
have everything ready for abandoning ship. Intimate the facts of the
case by wireless telegraphy. Head the ship for the nearest port or
beach should she be near the coast.
I would keep in mind that water sprayed on burning oil from a
nozzle having perforations is more effective than a stream of water.
FIRE APPLIANCES as RECOMMENDED by the BOARD OF TR/VDE
Foreign-going Cargo Ships.
(a) Steamships of 2000 gross tonnage and upwards.—At least two
steam or equivalent pumps shall be available, each of which is capable
of providing a full supply of wateT to a range of metal service pipes,
fitted with branches at intervals of about 60 feet so arranged that the
fire hoses, of which two shall be provided, may be readily coupled
thereto, and two powerful jets of water may be rapidly and simultane¬
ously brought to bear upon each space occupied by officers' and
trew, or upon any part of each cargo space, or upon each coal
bunker space.
In addition, satisfactory means shall be provided whereby steam
may be conveyed to each closed-in cargo compartment.
Two smoke helmets of an approved type (stowed in separate places)
and 12 fire buckets shall be provided*
All foreign-going cargo steamships shall have at least two chemical
fire extinguishers in each compartment of the machinery space where oil
is used. A portable chemical fire extinguisher shall be available for
immediate use in edch space occupied by the officers and crew, but the
total number provided for these spaces need not exceed six.
In all vessels which use oil fuel, in addition to the water service to
176
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
these spaces, satisfactory provision shall be made for the admission of
steam to the lower part of the boiler rooms.
A receptacle containing a suitable quantity of sand shall be placed
in each firing space where oil fuel is used, and suitable scoops for
distributing the sand shall also be provided.
In the case of steamships carrying deck cargoes, the fire service
pipes must be so arranged that the required number of hydrants are
always accessible.
Fire Hose.—The fire hoses may be made of leather, seamless hemp
or flax canvas of first-class quality, or other approved material. There
shall be provided 50 per cent, more than the minimum quantity necessary
to meet the requirements of the previous rules and the following clause.
The hoses shall be provided with suitable metal unions and conductors,
and with gooseneck connections where necessary, and shall be of such
length that when in position a jet of water may be projected to any
part of the space in which they are used.
The fire hoses, conductors, etc., shall be kept ready for use, in
conspicuous positions near the water service connections, and shall be
used only for the purpose of extinguishing fires, or for testing the
apparatus at fire drills and surveys.
Pipes to Holds, etc.—The pipes for conveying steam to holds or
other compartments shall be provided with controlling valves suitably
marked to indicate the compartments to which the pipes are respectively
led. Suitable provision shall be made for locking these valves, as a
precaution against the inadvertent admission of steam to any compart¬
ment. If any pipe is led to a space to which passengers have access,
it shall be furnished with an additional stop valve, capable of being
locked, or some other device providing the requisite security from
danger should be adopted.
Portable Chemical Fire Extinguishers.—The recommendations with
regard to chemical fire extinguishers apply only to apparatus of an
approved fluid type, the capacity of which shall not be, as a rule, less
than 2 gallons.
The extinguishers on any vessel shall not be of mote than two kinds.
They shall be kept where likely to prove most serviceable in cases of
emergency, and shall bear on each apparatus printed instructions
regarding its use, and the maker's dated guarantee as to the sufficiency
of the extinguisher for the pressure generated when it is put into action.
Fire Drill.—Fire drill shall 1 be observed at least once a month in all
foreign-going cargo vessels. The great utility of woollen or asbestos
FIRE APPLIANCES
177
blankets for smothering small fires should always be borne in mind at
fire drills.
Annual Inspection.—The fire-extinguishing appliances shall be
thoroughly examined by an approved Surveyor at least once every
12 months.
At these inspections all the fire hoses, both working and spare,
shall be tested under working conditions, and any defects which may
be discovered shall be made good to the Surveyor’s satisfaction.
A fair proportion of the chemical fire extinguishers shall likewise be
tested (if possible in the presence of the men likely to use them in case
of emergency): and afterwards recharged, or, if considered to be defective
replaced by new ones. Before testing a chemical fire extinguisher,
the Surveyor shall carefully examine the apparatus and satisfy himself
as to its sufficiency for the pressure which it may have to sustain, and
for this purpose the charge shall be withdrawn.
Muster List.—The muster list assigns duties to the different members
of the crew in connection with:—
(a) The closing of watertight doors, valves, etc.
(b) The equipment of the boats, life-rafts and buoyant apparatus
generally.
(c) The launching of the boats attached to davits.
(d) The general preparation of the other boats, the life-rafts and
buoyant apparatus.
(e) The muster of the passengers.
(j) The extinction of fire.
The muster list also assigns to the members of the stewards’ depart¬
ment their several duties in relation to the passengers at a time oi
emergency.
(a) Warning passengers.
(b) Seeing that they are dressed and have put on their life-jackets
in a proper manner.
(c) Assembling the passengers at muster stations.
(d) Keeping order in the passages and on the stairways, and,
generally, controlling the movements of the passengers.
Musters and Drills.—Musters of the crew for boat drill shall take place
weekly when practicable, and in vessels in which the voyage exceeds
one week, before leaving port.
Different groups of boats shall be used in turn at successive boat
drills. The drills and inspections shall be sq arranged that the crew
178
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
thoroughly understand and are practised in the duties they have to
perform, and that all life-saving appliances with the gear appertaining
to them are always ready for immediate use.
STANDING RULES FOR STEAM VESSELS AT SEA
Officer of the watch to keep his look-out on the bridge, not leaving
it except when necessary. At night he will be careful to see, from time
to time, that the side and masthead lights are burning brightly, and
kept trimmed; that the look-out man is at his post, and that the ship is
steered her course. Where an order book is not kept, the course given
to be marked on the log slate (which should always be kept in the
chartroom), the officer relieving to examine same before taking charge.
The bearing of the North star to be noted frequently and entered in the
log, with the direction of the ship’s head at the time of observation.
Amplitudes and Azimuths never to be neglected. All courses given are
by the bridge or standard compass. The officer in charge of the d'eck
to observe if any change or difference takes place between any or
either of the compasses, i.e . more than usual, if so, call the master.
The patent log should be read every two hours and entered up,
mechanism to be oiled at least once a day (at noon) by the quarter¬
master who should report having done so to the officer of the Watch.
Barometer registered every four hours and to be frequently noted
during unsettled weather. Masters and officers are respectfully requested
never to forget the four L’s— Lead, Log, Latitude and Look-out.
No chartroom ought to be without the celestial maps hung up.
The master, when leaving the deck for rest, shall see that chart
is on the table for the use of the officer in charge, with instructions to be
called on all occasions of doubt.
Pump wells to be sounded by carpenter at 8 a.m. and at 8 p.m., and
to be reported to chief officer who reports same to captain previous
to making eight bells; and wells to be sounded not less than once in four
hours during bad weather, any unusual quantity of water to be
reported to captain and engineer of watch. Carpenter to note soundings
on the board (where one is kept) in addition to verbal report. Officer
of the watch to report changes of weather, particularly so in cases of
fog, heavy rains and haze, a large number of ships, or anything unusual
connected with the ship, such as thick volumes of smoke going right
ahead, so that the course may be altered if prudent to do so.
Watch on deck to'be kept round the wheelhouse, so as to be ready
STANDING ORDERS
179
for officer’s orders, and save him from leaving the bridge to look for the
hands.
Master, officers, and carpenter to see that all steering gear is in
working order.
Chief officer to see that the forecastle is cleaned out at proper times;
also to see the winches are always in working order.
Carpenter to work all sluice valves once a week, and as a rule keep
them closed at sea, except when wanted to run water to engine-room.
Carpenter to look after all tarpaulins and wedges for hatchway
battens, and during fine weather the ventilator covers are to be taken
off, also one hatch from each hatchway, and to be closed again before
dark. Chief officer to see that the coal trimmers keep the grating on
bunker holes, and put covers on every evening coming in dark; any
neglect of this to be reported to the chief engineer.
The ash shoot is to be used for the purpose of keeping the Bhip
clean.
GENERAL RULES TO RE OBSERVED ON BOARD SHIP IN PORT
OR AT ANCHOR.
Deck never to be left without a look-out. The officer to see that
the anchor lamp is burning brightly and to be on deck at the turn of
the tide when the ship is swinging round. , Watch for ship dragging
anchor by noting if bearings of shore objects remain the same; pay
out cable if it comes on to blow; ring the bell if it comes on fog.
Chief officer has general charge, and will see that a proper account
of cargo and stores is kept both in taking in and discharging, and also
see that the carpenter looks at limbers, and sees that the pumps are
all clean and tank cocks in working order, and all scuppers clear in
’tween decks before cargo is stowed there.
Second officer, and also third, will be under directions of chief,
either to tally cargo or to look after holds, and, if necessary, to keep a
hold book. Ship never to be left without an officer on board except in
harbour or dock, and not then until the watchman takes charge, and
watchman not to leave until one of the officers returns.
QUESTIONS.
1 What are the usual commands on bridge telegraphs (a) to the
engine room, (b) to the officer aft when docking?
% Describe how a telegraph works.
180 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
3. What is a navigation light sentinel?
4. Describe the marks on the hand lead line and on the deep sea line.
5. What soundings would you call out for:— (a) leather with a hole
in it; (b) first red rag 6 feet below the surface; (c) blue rag 6 feet above
the surface; ( d ) second white rag 3 feet above the surface; (e) second
red rag 18 inches below the surface?
6. Describe how a cast of the deep sea lead would be taken steaming
before the wind'and sea.
7. Describe taking a cast with a patent depth recorder. How can
you tell when the lead has touched bottom?
8. What is the principle of the atmospheric sounding tube.
9. Write out the best* description you can of the Echo Sounding
Machine.
10. What is the principle followed in measuring off the length of the
knot on the hand log line?
11. Describe a patent towing log.
12. Describe any electrical type of speed recorder you may know
about.
13. Supposing all speed recorders were lost how could you arrive at
the ship’s speed? I
14. Write out equations connecting the ship’s speed with coal
consumption.
15. Describe a sluice valve, how it is operated and the manner
in which they are fitted.
16. What are the requirements of a steering gear?
17. Describe a type of steam steering gear and how the rudder is
operated by the helmsman.
18. What advantages are claimed for telemotor steering gear?
Describe how it works.
19. Describe the emergency steering gear in any ship you have
served in.
20. Describe the mechanism of a steam winch and how it works.
What precautions should be taken before starting and stopping a
winch, particularly so in cold weather. Steam is escaping badly from
the cylinders of a winch, describe how you would repack the glands
and make it steamtight.
21. Name the essential parts of a reciprocating marine steam engine.
22. What are the fundamental differences between a Scotch boiler
and a water-tube boiler? State the advantages and disadvantages of
each.
QUESTIONS
181
23. Describe the fundamental differences in the working principles
of a reciprocating steam engine and a turbine steam engine.
24. Trace the complete circulation of the steam from the boiler
and back again and what it does at successive stages of its journey.
25. State what you know of a motorship and the advantages claimed
for the internal combustion engine
26. Describe the construction and principle of a mercurial barometer.
27. What precautions must be taken when mounting and unmount¬
ing a barometer for transport?
28. What is (a) a millibar, (b) a vernier?
29. What is “error of capacity” and why is it not applied to readings
of the marine type of barometer?
30. Describe an aneroid barometer. How does it differ from a
mercury barometer?
31. How may an aneroid be converted into a barograph?
32. Write down the freezing and boiling temperatures of fresh
water as indicated on the Fahrenheit, Centigrade and Absolute scales.
33. How is zero temperature Absolute arrived at ?
34. Convert 132° Fahr. into Centigrade and Absolute.
60° Centigrade into Fahrenheit and Absolute.
150°-Absolute into Fahrenheit and Centigrade.
35. Describe the maximum and the minimum thermometers and
state how these extremes are recorded.
36. Describe the construction, principle and use of a hygrometer.
37. In what kind of weather would you expect the greatest differences
in the wet and dry bulb thermometers? Which reads the lower?
38. What is a rain gauge? What is meant by 1 inch of rainfall?
39. Explain a method of receiving a wireless telegraphy directional
bearing on board ship. Is any correction of the radio bearing necessary
to obtain the true bearing of the distant station?
40. What standing orders are usually observed on board ship (a)
at sea, (5) at anchor, (c) in dock?
41. Describe the fire-extinguishing appliances on board your ship.
42. The seat of fire in a hold is inaccessible, what steps might be
taken to subdue it?
43. How is a chemical fire extinguisher worked?
44. What is “Firefoam” and how is it used?
45. Describe any fire detecting and extinguishing system you know of.
46 Describe the procedure of any organised fire drill you have taken
part in and the duties of the various members of the crew.
182 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
47. How often is the file-extinguishing apparatus inspected?
48 Assuming the emergency signal to have been made on the steam
whistle at sea, “all hands and passengers muster at stations,”
state what particular duties should be performed by the mem¬
bers of (a) the deck department, (b) the engine department, (c) the
cabin department.
49. A steamer burns 24 tons of fuel per day when steaming 8 knots,
find the approximate consumption if speed is increased to 9 knots
and again to 10 knots.
Am .—34 tons; 47 tons.
50. The consumption at 12 knots being 40 tons per day, find what
the approximate consumption will be if speed is reduced to 10 knots.
Am.— 23-1 tons.
51. A steamer has accomplished 1200 miles at 10 knots with a
consumption of 140 tons of fuel, she has still 1400 miles to go with only
100 tons left. Required the reduced speed to reach destination.
Am. —7*8 knots.
52. A vessel has steamed 1500 miles at 10 knots burning 40 tons of
coal daily, find her consumption to do 12 knots if she had 1200 miles to
complete the passage.
Am .—288 tons or about 69 tons per day.
53. Name the three corrections to be applied to barometer readings
to reduce them to standard, and state why they are necessary.
54. What is the error of capacity and why is it not necessary to
apply it to marine barometers ?
55. Describe hydraulic water-tight doors as usually fitted in large
passenger steamers.
56. What conditions must an approved steering gear fulfil ?
57. State the more important of the General Standing Orders adopted
in all well conducted ships (a) at sea, (6) at anchor, (c) in dobk.
CHAPTER IX.
REGULATIONS FOR PREVENTING COLLISIONS AT SEA
Their vital importance.—The very object of these Regulations, viz.,
the Prevention of Collisions at Sea, is sufficient to indicate their vital
importance, and should impress upon everyone who wishes to be capable
of taking charge of a vessel at sea the absolute necessity of being
thoroughly familiar with them.
JTheir importance at sea is duly reflected in the examination room
where they form the most important feature of the viva-voce examination
of masters and mates. Candidates should note this, and bear in mind
the fact that the examination in this subject will be a very rigorous
one.
The Regulations should be committed to memory.—The question
is frequently asked: “Must I learn the articles word for word?” Now
* although in many of the subjects of examination the committing to
memory of fixed rules or answers is not to be recommended, but rather
the reverse, with these Regulations it is different. Here the precise
wording has been definitely fixed, and any alteration or misplacement
of the wording may entirely alter their meaning, therefore it is important
to be exact; also candidates may be asked to repeat any of the Articles.
But you must not suppose that merely being able to repeat them is
sufficient. The meaning of each Article must be understood as well as
, their relation to each other, and as a seaman you must understand their
practical application. The examiners are careful to see that such is the
case before granting any candidate a certificate.
We have sectioned off the subject into three chapters.
In Chapter IX. the full text of Articles 1 to 16 is given dealing with
lights and fog signals, then a brief resume of each Article with
illustrations followed by a few questions and answers.
In Chapter X. the full text of the remaining Articles, 17 to, 31, Steering
and Sailing Rules, is given followed by a few questions and answers.
183
181 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Then numerous illustrations and exercises on the probable direction
a vessel showing her sidelights may be heading and what to do under
various circumstances.
This section should be carefully studied and read over and over
again. The relative conditions must be intelligently visualised, for
there is no other way of becoming thoroughly familiar with the
examination side of the Rule of the Road at Sea.
Chapter XI. deals with the Notices to Mariners, system of buoyage
and various supplementary regulations for adding to the safety of life
and property at sea.
REGULATIONS FOR PREVENTING COLLISIONS
AT SEA.
Preliminary.
These Rules shall be followed by all vessels upon the high seas
and in all waters connected therewith, navigable by sea-going vessels.
In the following Rules every steam vessel which is under sail
and not under steam is to be considered a sailing vessel, and every
vessel under steam, whether under sail or not, is to be considered a
steam vessel.
The word “ steam vessel ” shall include any vessel propelled by
machinery.
A vessel is “ under way ” within the meaning of these Rules
when she is not at anchor, or made Hst to the shore, or aground.
Rules Concerning Lights, etc.
The word “ visible ” in these Rules, when applied to lights,
shall mean visible on a dark night with a clear atmosphere.
Lights.
Akt. 1.—The Rules concerning lights shall be complied with
In all weathers from sunset to sunrise, and during*such time no
other lights which may be mistaken for the prescribed lights shall,
be exhibited.
Steam Ships.
Abt. 2.—A steam vessel when under way shall carry-—
(a) On or in front of the foremast, or if a vessel without a
foremast, then in the fore part of the vessel, at a height
SHIPS 5 LIGHTS AND REGULATIONS
185
above the hull of not less than 20 feet, and if the breadth
of the vessel exceeds 20 feet, then at a height above the
hull not less than such breadth, so, however, that the
light need not be carried at a greater height above the
hull than 40 feet, a bright white light so constructed
as to show an unbroken light over an arc of the horizon
of 20 points of the compass, so fixed as to throw the light
10 points on each side of the vessel, viz., from right ahead
to 2 points abaft the beam on either side, and of such a
character as to be visible at a distance of at least 5 miles.
(&) On the starboard side a green light so constructed
as to show an unbroken light over an arc of the horizon
of 10 points of the compass, so fixed as to throw the light
from right ahead to 2 points abaft the beam on the star¬
board side, and of such a character as to be visible at a
distance of at least 2 miles.
(c) On the port side a red light so constructed as to show
an unbroken light over an arc of the horizon of 10 points
of the compass, so fixed as to throw the light from right
ahead to 2 points abaft the beam on the port side, and of
such a character as to be visible at a distance of at least
2 miles.
(d) The said green and red side-lights shall be fitted with
inboard screens projecting at least 3 feet forward from
the light, so as to prevent these lights from being seen
across the bow.
(e) A steam vessel when under way may carry an additional
white light similar in construction to the light men¬
tioned in sub-division ( a ). These two lights shall be so
placed in line with the keel that one shall be at least
15 feet higher than the other, and in such a position with
reference to each other that the lower light shall be forward
of the upper one. The vertical distance between these
lights shall be less than the horizontal distance.
Steam Vessels When Towing.
Art. 3.—A steam vessel when towing another vessel shall, in
addition to her side-lights, carry two bright white lights in a
vertical line one over the other, not less than 6 feet apart, and
18& NTCHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
when towing more than one vessel shall carry an additional
bright white light 6 feet above or below such lights, if the length
of the tow, measuring from the stem of the towing vessel to the
stem of the last vessel towed, exceeds 600 feet. Each of these
lights shall be of the same construction and character and shall be
carried in the same position as the white light mentioned in Article 2
(a), except the additional light, which may be carried at a height
of not less than 14 feet above the hull.
Such steam vessel may carry a small white light abaft the
funnel or aftermast for the vessel towed to steer by, but such light
shall not be visible forward of the beam.
Vessels not under Command and Cable Ships.
Art. 4.— (a) A vessel which from any accident is not under
command shall carry at the same height as the white light men¬
tioned in Article 2 (a), where tjiey can best be seen, and, if a steam
vessel, in lieu of that light, two bed lights, in a vertical line one
over the other, not less than 6 feet apart, and of such a character as
to be visible all round the horizon at a distance of at least 2 miles •
and shall by day carry in a vertical line one over the otheT. not less
than 6 feet apart, where they can best be seen, two black balls ob
shapes, each 2 feet in diameter.
(6) A vessel employed in laying or in picking up a telegraph
cable shall carry in the same position as the white light mentioned
in Article 2 (a), and, if a steam vessel, in lieu of that light, thbee
lights in a vertical line one over the other, not less than 6 feet
apart. The highest and lowest of these lights shall be red, and
the middle light shall be white, and they shall be of such a character
as to be visible all round the horizon, at a distance of at least 2
miles. By day she shall carry in a vertical line one over the other,
not less than 6 feet apart, where they can best be seen, three shapes
not less than 2 feet in di am eter, of which the highest and l owe st
shall be globular in shape and red in colour, and the middle one
diamond in shape and w hite .
(c) The vessels referred to in this Article, when not making
way through the water, shall not carry the side-lights, but when
making way shall carry them.
(d) The lights and shapes required to be shown by this Article
are to be taken by other vessels as signals that the vessel showing
ships’ lights and regulations 187
them is not under command and cannot therefore get out of the
way. - #
These signals are not signals of vessels in distress and requiring
assistance. Such signals are contained in Article 31.
Sailing Vessels and Vessels being Towed.
Art. 5.—A sailing vessel under way, and any vessel being
towed, shall carry the same lights as are prescribed by Article 2
for a steam vessel tinder way, with the exception of the white
lights mentioned therein, which they shall never carry.
Small Vessels in Bad Weather.
Art. 6.—Whenever, as in the case of small vessels under way
during bad weather, the green and red side-lights cannot be fixed,
these lights shall be kept at hand lighted and ready for use ;
and shall, on the approach of or to other vessels, be exhibited on
their respective sides in sufficient time to prevent collision, in such
manner as to make them most visible, and so that the green light
shall not be seen on the port side nor the red light on the starboard
side, nor, if practicable, more than 2 points abaft the beam on their
respective sides.
To make the use of these portable lights more certain and easy,
the lanterns containing them shall each be painted outside with the
colour of the light they respectively contain, and shall be provided
with proper screens.
Lights for Small Vessels.*
Art. 7.—Steam vessels of less than 40, and vessels under oars
or sails of less than 20 tons, gross tonnage, respectively, and rowing
boats, when under way, shall not be obliged to carry the lights
mentioned in Article 2 (a) (b) and (c), but if they do not carry them
they shall be provided with the following lights :—
1. Steam vessels of less than 40 tons shall carry—
: (a) In the fore part of the vessel, or on or in front of the
funnel, where it can best be seen, and at a height above
the gunwale of not less than 9 feet, a bright white
light constructed and fixed as prescribed in Article 2
(a), and of such a character as to be visible at a distance
of at least 2 miles. ,
(2i) Green and red side-lights constructed and fixed as
183 NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
prescribed in Article 2(b) and (c) and of such a character
, as to be visible at a distance of at least J mile, or a
combined lantern showing a green light and a red
light from right ahead to 2 points abaft the beam on
their respective sides. Such lantern shall be carried
not less than 3 feet below the white light,
2. Small steamboats, such as are carried by sea-going vessels,
may carry the white light at a less height than 9 feet
above the gunwale, but it shall be carried above the
combined lantern mentioned in sub-division 1 (6).
3. Vessels under oars or sails, of less than 20 tons, shall have
ready at hand a lantern with a green glass on
one side and a red glass on the other, which on
the approach of or to other vessels, shall be exhibited in
sufficient time to prevent collision, so that the green
light shall not be seen on the port side nor the red
light on the starboard side.
4 . Rowing boats, whether under oars or sail, shall have
ready at hand a lantern showing a white light,
which shall be temporarily exhibited in sufficient time
to prevent collision.
The vessels referred to in this Article shall not be obliged to
carry the lights prescribed by Article 4 (a), and Article 11, last
paragraph.
Pilot Vessels.
Art. 8 . —Pilot vessels, when engaged on their station on
pilotage duty, shall not'show the lights required for other vessels,
but shall carry a white light at the masthead, visible all round
the horizon, and shall also exhibit a flare-up light or flare-up lights
at short intervals, which shall never exceed fifteen minutes.
On the near approach of or to other vessels they shall have
their side-lights lighted, ready for use, and shall flash ofi show
them at short intervals, to indicate the direction in which they
are heading, but the green light shall not be shown on the port side,
nor the red light on the starboard side.
A pilot vessel of such a class as to be obliged to go alongside of
a vessel to put a pilot on board may show the white light instead
of carrying it at the masthead, and may, instead of the coloured
SHIPS* lights and regulations
I8&
lights above mentioned, have at hand ready for use a lantern with
a green glass on the one side and a red glass on the other, to be
used as prescribed above.
A steam pilot vessel exclusively employed for the service of
pilots licensed or certified by any pilotage authority, or the com¬
mittee of any pilotage district, when engaged on her station on
pilotage duty and not at anchor, shall, in addition to the lights
required for all pilot boats, carry at a distance of 8 feet below her
white masthead light a red light visible all round the* horizon and
of such a character as to be visible on a dark night with a clear
atmosphere at a distance of at least 2 miles, and also the coloured
side-lights required to be carried by vessels when under way.
When engaged on her station on pilotage duty and at anchor, she
shall carry, in addition to the lights required for all pilot boats, the
red light above mentioned, but not the coloured side-lights.
Pilot vessels, when not engaged on their station on pilotage
duty, shall carry lights similar to those of other vessels of their
tonnage.
Fishing Vessels.
Abt. 9.*t—Fishing vessels and fishing boats, when under way
and when not required by this Article to carry or show the lights
hereinafter specified, shall carry or show the lights prescribed for
vessels of their tonnage under way.
(a) Open boats, by which it is to be understood boats not pro¬
tected from the entry of sea water by means of a con¬
tinuous deck, when engaged in any fishing at night,
with outlying tackle extending not more than 150 feet
horizontally from the boat into the seaway, shall carry
one all-round white light.
Open boats, when fishing at night, with outlying tackle
extending more than 150 feet horizontally from the boat
into the seaway, shall carry one all-round white light,
and in addition, on approaching or being approached by
other vessels, shall show a second white light at least 3
feet below the first light and at a horizontal distance of
at least 5 feet away from it in the direction in which the
outlying tackle is attached.
♦ This Article does not apply to Chinese or Siamese vessels.
tThe expression “Mediterranean Sea *' contained in sub-sections (6) and (c) of
Article includes the Black Sea and the other adjacent inland seas in communication with it.
190
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
(6) ^Vessels and boats, except open boats as defined in sub«
division (a), when fishing with drift nets, shall, so long as
the nets are wholly or partly in the water, carry twc
white lights where they can best be seen. Such lights
shall be placed so that the vertical distance between
them shall be not less than 6 feet and not more than 15
feet, and so that the horizontal distance between them,
measured in a line with the keel, shall be not less than
5 feet and not more than 10 feet. The lower of these
two fights shall be in the direction of the nets, and both
of them shall be of such a character as to show all round
the horizon, and to be visible at a distance of not less
than 3 miles.
Within the Mediterranean Sea and the seas bordering
the coasts of Japan and Korea f sailing fishing-vessels of
less than 20 tons gross tonnage shall not be obliged to
carry the lower of these two lights ; should they, however,
riot carry it, they shall show in the same position (in the
direction of the net or gear) a white light, visible at a
distance of not less than one sea mile), on the approach
of or to other vessels.
(c) Vessels and boats, except open boats as defined in sub¬
division (a), when line-fishing with their lines out and
attached to or hauling their lines and, when not at anchor
or stationary within the meaning of sub-division (h),
shall carry the same lights as vessels fishing with drift
nets. When shooting lines, or fishing with towing lines,
they shall carry the lights prescribed for a steam or sailing
vessel under way respectively.
Within the Mediterranean Sea, and in the seas border¬
ing the coasts of Japan and Korea, J sailing fishing-vessels
of less than 20 tons gross tonnage shall not be obliged to
carry the lower of these two lights ; should they, however,
not carry it, they shall show in the same position (in the
direction of the lines) a white light, visible at a distance
boats when In the “hoy* or hand-hne fishing, will carry
die fights prescribed for vessels fishing with drift nets. 8 cany
of ^ “ regardfl Tesaeb < to the seas (excluding the Baltic) bordering the coasts
of ItotiL 0 ’ “ reg ” dB EQSSian Ve68eIs> to the seas (excluding the Baltic) bordering the coasts
ships' lights and regulations
191
of not less than 1 sea mile on the approach of or to other
vessels.
(d) Vessels, when engaged in trawling, by which is meant
the dragging of an apparatus along the bottom of the sea—
1. If steam vessels, shall carry in the same position
as the white light mentioned in Article 2 (a), a tricoloured
lantern so constructed and fixed as to show a white
light from right ahead to 2 points on each bow, and
a green light and a red light over an arc of the horizon
from 2 points on each bow to 2 points abaft the beam
on the starboard and port sides respectively; and not
less than 6 nor more than 12 feet below the tricoloured
lantern a white light in a lantern, so constructed as to
show a clear, unif orm and unbroken light all round the
horizon.
2. If sailing vessels, shall carry a white light in a
lantern, so constructed as to show a clear, uniform and
unbroken light all round the horizon, and shall also,
on the approach of or to other vessels, show, where it can
best be seen, a white flare-up light or torch in sufficient
time to prevent collision.
All lights mentioned in sub-division (d), 1 and 2, shall
be visible at a distance of at least 2 miles.
(«)* Oyster dredgers and other vessels fishing with dredge-
nets shall carry and show the same lights as trawlers.
(/) Fishing-vessels and fishing-boats may at any time use
a flare-up light in addition to the lights which they are
by this Article required to carry and show, and they may
also use working lights.
(g) Every fishing-vessel and every fishing-boat under 150
feet in length, when at anchor, shall exhibit a white
light visible all round the horizon at a distance of at least
1 mile.
Every fishing-vessel of 150 feet in length or upwards,
when at anchor, shall exhibit a white light visible all
round the horizon at a distance of at least 1 mile, and
shall exhibit a second light as provided for vessels at
such length Dy Article 11.
192
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Should any such vessel, whether under 150 feet
in length, or of 150 feet in length or upwards, be attached
to a net or other fishing gear, she shall on the approach
of other vessels show an additional white light at least
3 feet below the anchor light, and at a horizontal distance
of at least 5 feet away from it in the direction of the
net or gear.
(A) If a vessel or boat when fishing becomes stationary
in consequence of her gear getting fast to a rock or other
obstruction, she shall in day-time haul down the day-
signal required by sub-division (k ); at night show the
light or lights prescribed for a vessel at anchor ; and during
fog, mist, falling snow, or heavy rain-storms make the
signal prescribed for a vessel at anchor. (See sub-division
(d), and the last paragraph of Article 15.)
(i) In fog, mist, falling snow or heavy rain-storms, drift-
net vessels attached to their nets, and vessels when
trawling, dredging, or fishing with any kind of dragnet,
and vessels line-fishing with their lines out, shall, if of
20 tons gross tonnage or upwards, respectively, at inter¬
vals of not more than one minute, make a blast; if steam
vessels, with the whistle or syren; and if sailing vessels
with the fog-horn ; each blast to be followed by ringing
the bell. Fishing-vessels and boats of less than 20 tons
gross tonnage shall not be obliged to give the above men¬
tioned signals ; but if they do not, they shall make some
other efficient sound signal at intervals of not more than
one minute.
(k) All vessels or boats fishing with nets or lines or trawls,
when under way, shall in day time indicate their occupa¬
tion to an approaching vessel by displaying a basket or
other efficient signal where it can best be seen. If vessels
or boats at anchor have their gear out, they shall, on the
. approach of other vessels, show the same signal on the
side on which those vessels can pass.
The vessels required by this Article to carry or show the lights
hereinbefore specified shall not be obliged to carry the fights pre¬
scribed by Article 4 (a), and the last paragraph of Article 11
ship's lights and regulations
193
Stern Light.
Art. 10.—A vessel which is being overtaken by another shall
show from her stem to such last-mentioned vessel a white light or
A FLARE-UP LIGHT.
The white light required to be shown by this Article may be
fixed and carried in a lantern, but in such case the lantern shall be
so constructed, fitted, and screened that it shall throw an unbroken
light over an arc of the horizon of 12 points of the compass, viz.,
for 6 points from right aft on each side of the vessel, so as to be
visible at a distance of at least 1 mile. Such light shall be carried
as nearly as practicable on the same level as the side-lights.
Vessels at Anchor.
Art. 11.—A vessel under 150 feet in length, when at anchor,
shall carry forward, where it can best be seen, but at a height not
exceeding 20 feet above the hull, a white light in a lantern so
constructed as to show a clear, uniform and unbroken light visible
all round the horizon at a distance of at least 1 mile.
A vessel of 150 feet or upwards in length, when at anchor,
shall carry in the forward part of the vessel, at a height of not
less than 20, and not exceeding 40 feet above the hull, one such light,
and at or near the stern of the vessel, and at such a height that
it shall not be less than 15 feet lower than the forward light, an¬
other SUCH LIGHT.
The length of a vessel shall be deemed to be the length appearing
in her certificate of registry.
A vessel aground in or near a fairway shall carry the above
light or lights and the two red lights prescribed by Article 4 (a).
Signal to Attract Attention.
Art. 12.—Every vessel may, if necessary in order to attract
attention, in addition to the lights which she is by these Rules
required to carry, show a flare-up light or use any detonating
signal that cannot he mistaken for a distress signal.
Special Recognition Signals.
Art. 13.—Nothing in these Rules shall interfere with the opera¬
tion of any special Rules made by the Government of any nation
with respect to additional station and signal lights for two or
more ships of war or for vessels sailing under convoy, or with the
H
194 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
exhibition of recognition signals adopted by shipowners, which
have been authorised by their respective Governments, and duly
registered and published.
Steamship Under Sail.
Art. 14.—A steam vessel proceeding under sail only, but having
her funnel up, shall carry in daytime, forward, where it can best
be seen, one black ball or shape 2 feet in diameter.
Sound Signals for Fog, etc.
'--Art 15.—All signals prescribed by this Article for vessels under
way shall be given—
1. By “ steam vessels ” on the whistle or siren.
2. By “ sailing vessels and vessels towed ” on the fog-horn.
The words “ prolonged blast 55 used in this Article shall mean
a blast of from 4 to 6 seconds’ duration.
A steam vessel shall be provided with an efficient whistle or
siren, sounded by steam or some substitute for steam, so placed
that the sound may not be intercepted by any obstruction, and
with an efficient fog-horn, to be sounded by mechanical means,
and also with an efficient bell* A sailing vessel of 20 tons gross
tonnage or upwards shall be provided with a similar fog-horn and
beH.
In fog, mist, falling snow, or heavy rain-storms, whether by
day or night, the signals described in this Article shall be used as
foHows, viz. :—
(a) A steam vessel having way upon her shaU sound, at
intervals of not more than 2 minutes, a prolonged blast.
(b) A steam vessel under way, but stopped and having
no way upon her, shall sound, at intervals of not more
than 2 minutes, two prolonged-blasts, with an interval
of about 1 second between them.
(c) A sailing vessel under way shall sound, at intervals of
not more than 1 minute, when on the starboard tack
one blast, when on the port tack two blasts in sue-
, and when with the win 1) abaft the beam three
blasts in succession.
hoard ^ S'**; reguire a bell io be used, a drum may be substituted on
board Taridsh vessels, ox a gong where such articles are used on hoard small sea-goiag vessel
0)
o
• •
ART, a
(*>
o
o
( 7 )
o
ART. A
(«o)
o
ART 8
( 13 )
0 )
00
0
("0
FIG. 2
ships’ lights and regulations
195
(d) A vessel when at anchor shall, at intervals of not more
than 1 minute, ring the bell rapidly for about 5 seconds.
(e) A vessel when towing, a vessel employed in laying or
in picking up a telegraph cable, and a vessel under way,
which is unable to get out of the way of an approaching
vessel through being not under command, or unable
to manoeuvre as required by these Rules shall, instead
of the signals prescribed in sub-divisions (a) and ( c) of
this Article, at intervals of not more than two minutes,
sound three blasts in succession, viz., one prolonged
blast followed by two short blasts. A vessel towed
may give this signal and she shall not give any other.
Sailing vessels and boats of less than 20 tons gross tonnage
shall not be obliged to give the above-mentioned signals, but if
they do not, they shall make some other efficient sound signal at
intervals of not more than 1 minute, f
Speed of Ships to be Moderate in Fog, etc.
Art. 16,—Every vessel shall, in fog, mist, falling snow or heavy
rain-storms, go at a moderate speed, having careful regard to
the existing circumstances and conditions.
A steam vessel hearing, apparently forward of her beam, the
fog-signal of a vessel, the position of which is not ascertained, shall,
so far as the circumstances of the case admit, stop her engines,
and then navigate with caution until danger of collision is over.
NAVIGATION LIGHTS.
Significance of Lights and Signals in Diagrams 1 to 19.
The minimum range of visibility of white masthead lights is
5 miles, coloured lights 2 miles, anchor and stern lights (white),
1 mile, drift net and seine net fishing boats’ lights (white), 3 miles.
/ I. Art. 2.—A steam vessel under way, heading towards me,
showing masthead lights, also side-lights
f Dutch steam pilot-vessels, when engaged on their station on pilotage duty in fog, mist,
falling snow or heavy rain-storms are required to make at intervals of 2 minutes at most 1 long
blast with the siren, followed after 1 second by a long blast with the steam whistle, and again
after 1 second by a long blast on the siren. When not engaged on their station on pilotage
duty, they make the same signals as other steamships.
Tskeps’ lights and regulations
197
12. Art. 9. —A fishing vessel with outlying gear extending more
than 150 feet, or fishing with nets or lines. The lower light is in
the direction of the gear.
13. Art. 9.—A steam trawler. Tri-coloured lamp at masthead
showing white sector ahead from 2 points on each bow, green to star¬
board from 2 points on the bow to 2 points abaft the beam, red to
port from 2 points on the bow to 2 points abaft the beam, an all¬
round white light below the combined lantern ; (i) trawler showing
port side ; (ii) trawler head on ; (iii) trawler showing starboard side.
14. Art. 9.—A sailing trawler. White all round light at mast¬
head and a white flare-up when close to other vessels.
Vessels fishing with dredge nets show the same lights as trawlers.
A fishing vessel with gear foul of an obstruction on the bottom
becomes a vessel at anchor for the time being.
. The anchor lights for a fishing vessel are the same as for other
vessels.
15. Art. 9.—A fishing vessel by day showing a ball or basket at
the masthead when fishing
A fishing vessel in fog gives in quick succession— Sail, sound fog
horn and bell; Steam, sound whistle and bell.
16. Art. 10.—Vessel’s white stem light showing from right aft
to 2 points abaft the beam on either side.
16. Art. 11.—A vessel less than 150 feet at anchor.
IT. Art. 11.—A vessel over 150 feet at anchor, the higher light
is forward, the lower one at the stem.
Arts. 18 and 19.— A vessel aground in or near a fairway or
channel (18) over 150 feet ; (19) less than 150 feet.
A single white light, what may it be ?
(i) A, vessel’s stem light (ii) An anchor light, (iii) Steamer’s
masthead light (iv) Sailing trawler’s masthead light (v) Sailing
pilot vessel’s masthead light, (vi) Any small craft, (vii) A distant
shore light.
Two white lights vertical, what may they be ?
(i) A vessel at anchor end on. (ii) A steamer’s 2 masthead lights
end on. (ii) A tug boat’s masthead lights, (iv) A vessel fishing
With nets or lines end on. (v) A steam trawler end on.
198 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNdWLEDGE
QUESTIONS ON THE RULES CONCERNING LIGHTS, ETC.
Articles i to 14.
1. When is a vessel said to be under way?
When she is not at anchor, or made fast to the snore, or aground.
2. During what times must the Buies concerning lights be complied with?
In all weathers from sunset to sunrise; and during such time no
other lights which may be mistaken for any Regulation lights must be
exhibited.
3. What light or lights are required by the Regulations to be exhibited
by vessels at anchor?
If they are under 150 feet in length, one white light forward. If
of 150 feet or upwards, two white lights, one forward and one aft. This
applies to both steam and sailing vessels.
i
4. Where must the anchor light be exhibited in a vessel less than 150
feet m length?
Forward, where it can best be seen, and where there is the least*
chance of obstruction from spars,* etc. It must not be more than 20
feet above the hull.
5. Where must the two anchor lights be shown in vessels of 150 feet
and upwards?
One light must be shown forward, not less than 20 and not more
than 40 feet above the hull; the other must be at or near the stem and
at least 15 feet lower than the forward light.
6. In what direction or directions must the anchor lights show, and at
what distance must they be visible?
They must show a clear, uniform and unbroken light, visible all
round the horizon .at a distance of at least 1 mile.
7. What light or lights must a vessel aground in or near a fairway carry?
The light or lights prescribed for a vessel at anchor, and in addition
the two red lights for a vessel not under command.
8. Describe the masthead light for steam vessels.
It must be of such a character and so placed in position that it
will show an unbroken white light from right ahead to 2 points abaft
♦The forestay well clear of the foremast is the best position, as the masts
and funnel being in line will only obstruct it in one direction.
ships’ lights and regulations
199
the beam on each side (that is, over an are of 20 points), and be visible
at a distance of at least 5 miles.
9. Where must this masthead light be placed?
On, or in front’of, the foremast, or if the vessel has no foremast then
in the fore part of the vessel. It must be at least 20 feet above the
hull, and if the breadth of the vessel exceeds 20 feet, then at a height
not less than such breadth; it need not, however, be placed higher than
40 feet in any case.
10. Does this apply to every steam vessel?
It applies to all steam vessels over 40 tons gross tonnage. WTiere
the tonnage is less than 40 the masthead light may either be as above,
or if not as above may be placed on or in front of the funnel at least
9 feet above the hull, showing a bright white light over the same arc
visible at least 2 miles.
11. Do steam vessels under way carry an additional masthead light ?
A second one may be carried exactly similar to the first. They
must be placed in a line with the keel, the forward light at least 15 feet
lower than the after one, and the horizontal distance must be greater
than the vertical.
12. What advantage is gained by carrying two masthead lights?
Other vessels can see approximately the direction in which the one
showing two masthead lights is heading. If approaching end on or
nearly end on, the lights would appear vertical or nearly so. If broad¬
side on, the horizontal distance would appear greater than the vertical.
Also other vessels would notice if the course was being altered.
13. Describe the side-lights for steamers under way?
A green light on the starboard side, and a red one on the port side.
They must be fitted with inboard screens extending at least 3 feet for¬
ward from the light, and must be placed and constructed so as to show
an unbroken light from right ahead to 2 points abaft the beam, and to be
visible at least 2 miles.
14. What lights do sailing ships and vessels being towed carry?
The side-lights as described for steamers, but no masthead light*
15. What other light may vessels show?
A white light at the stem visible 6 points from right aft on each
side of the vessel at a distance of 2 miles.
200
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
16. When is a steamer engaged in towing required to carry three mast¬
head lights?
When towing more than one vessel if the length of the tow, measured
from the stern of the tug to the stern of the last vessel towed, exceeds
600 feet.
17 What lights are pilot vessels required to carry when on pilotage duty?
A white light at the masthead visible all round for 3 miles, and a
flare-up light at intervals not exceeding 10 minutes; also they must
have the side-lights ready for use on nearing any other vessel, and show
them at short intervals on their respective sides to indicate the direction
in which they are heading.
18. What are the special lights for steam pilot vessels on duty?
In addition to the white masthead light required for all pilot vessels
they must show a red light 8 feet below it, visible 3 miles all round the
horizon, whether at anchor or not. Also, when not at anchor, in addition
to the above red and white lights, the side-lights must be carried.
19. Are these lights for steam pilot vessels to be used in British waters
only, or are they International?
They are for the use of all nations.
20. Describe the lights and the day signals that vessels employed in
laying or picking up a telegraph cable are required to carry.
At night: They must carry in the same position as a steamer’s
masthead light, and if a steamer, in place of that light, three lights in a
vertical line not less than 6 feet apart; the highest and lowest of these
lights shall be red, and the middle light white, and each of them must
be visible all round the horizon at a distance of at least 2 miles. The
side-lights must also be earned if making headway.
By day: They must carry in a vertical line where they can best be
seen, and not less than 6 feet apart, three shapes at least 2 feet in
diameter, of which the*top and bottom must be globular and red, and
the middle one diamond in shape and white.
21. Describe the lights and the day signals for a vessel not under
At night: They must carry where they can best be seen, at the same
height as a steamer’s masthead light, and if a steamer, in lieu of that
light, two red lights in a vertical line not less than 6 feet apart, and
risible all ronnd the horizon at a distance of at least 2 rni'I^ The
side-lights must also he carried if making headway.
ships’ lights and regulations
201
By day: Two black balls or shapes, each 2 feet in diameter, in a
vertical line not less than 6 feet apart, to be placed where they can best
be seen.
22 Would you regard these lights and shapes as signals of distress?
No. They must be regarded as signals that the vessel showing
them is not under command, and is therefore unable to get out of the
way. This is also the case with the lights and shapes shown by vessels
engaged in laying or picking up telegraph cables.
23. If you were in a steamship, proceeding under sail only, what
signal must you show in the daytime?
A black ball 2 feet in diameter, placed forward where it can best
be seen.
24. Under the same conditions, what would you do at night?
Exhibit lights for a sailing ship.
25. If in a steamship your engines break down at night, what change
would you make in your lights?
Take down the masthead light or lights; if not under command I
would hoist the two red lights, leaving the side-lights in their places
if making headway, but taking them in, if not.
26. If you see a single white light, what vessel does that denote the
presence of?
* It may be a vessel at anchor less than 150 feet in length; the stern
light of a vessel I am overtaking; the masthead light of a steamer
whose side-lights are not visible; a sailing trawler engaged in trawling;
a fishing vessel with her gear foul of some obstruction; or a pilot vessel.
27. You see a flare-up light; what .does that indicate?
It may be a pilot vessel on her station; a ship signalling for a pilot;
a vessel trying to attract attention (Art. 12); a vessel fishing with nets
or trawls.
28. You see two white lights vertical; what vessel may that be?,
It may be a steamer approaching end on with two masthead-lights;
a steamer engaged in towing with her side-lights not visible; a vessel of
150 feet or upwards at anchor end on; a drift net vessel engaged in fishing
end on; or, a steam trawler approaching within 2 points of being end on.
H*
202 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
29. What lights are steam trawlers to carry when trawling, and not
being stationary in consequence of their gear being foul of a
rock or other obstruction?
All steam vessels when trawling must carry the following
arrangement of lights:—
A lantern placed in the same position as the masthead light would
be, and constructed and fixed so as to show a white light over an arc
of 4 points of the horizon, namely, from right ahead to 2 points on each
bow, and a red light from 2 points on the port bow to 2 points abaft the
port beam, and a green light from 2 points on the starboard bow to
2 points abaft the starboard beam; and, in addition, a white light in a
lantern constructed so as to show a clear, uniform, and unbroken light
all round the horizon—all these lights to be visible at least 2 miles.
This light must be carried lower than the combined lantern, so that the
vertical distance between them is not less than 6 nor more than 12 feet.
30. Describe the lights for sailing vessels when engaged in trawling?
Sailing vessels engaged in trawling must carry a white light in a
lantern showing a clear, uniform, and unbroken light all round the
horizon, visible at least 2 miles. They shall, also, on the approach of
or to other vessels, show, where it can best be seen, a white flare-up light
or torch in sufficient time to prevent collision.
31. What lights are vessels engaged in drift net fishing required to show?
Vessels and boats (except open boats) engaged in drift net fishing
shall carry two white lights where they can best be seen. The vertical
distance between them shall be not less than 6 feet and not more than
15 feet, and the horizontal distance, measured in a line with the keel,
shall be not less than 5 and not more than 10 feet. The lower of these
two lights shall be in the direction of the nets, and both must be visible
all round the horizon at a distance of not less than 3 miles.
32. May fishing vessels and open boats use flare-up lights in addition to
the above lights?
Yes. They may use flare-up lights at any time, and they may also
use working lights.
33. Describe the lights to be shown by open boats engaged in any
fishing at night. - 1
They.are to carry one all-round white light. If their outlying
tackle extends more than 150 feet horizontally from the boat into the
ships’ lights and regulations
203
seaway, they are on the approach of or to another vessel, to show
a second white light at least 3 feet below the first light, and at a
horizontal distance of at least 5 feet away from it in the direction of the
outlying tackle.
34. Describe the day signal for fishing vessels ?
When under way they shall display a basket where it can best be seen.
If at anchor with their gear out they shall, on the approach of other
vessels, show the same signal on the side on which those vessels can
pass.
35. How can you discern the difference at night between the lights of
drift net fishing vessel and those of a vessel at anchor?
Should the vessel be beam on to me a marked difference would be
apparent. If she was a drift net fishing vessel her lights would be close
together, if she was a vessel at anchor they would have a considerable
distance between them. This distinction would be lost if she was end
on or nearly end on.
Again, a drift net fishing vessel drifts to leeward of her nets, conse¬
quently the lower of her two lights which is in the direction of the nets
would be to windward of the higher one. A vessel at anchor riding
head to wind would have her higher light to windward. This fact
would enable me to distinguish one from the other,
A drift net fishing vessel is also likely to have working lights about
the deck while a vessel at anchor is not likely to have them.
A fishing vessel is also likely to show a flare-up light as I approach her.
36. Having decided what was the character of the vessel, in which
direction would you pass the lights?
I should pass to leeward of them in both cases. If she was a drift
net fishing vessel I should have to go round the higher light. If she
was a vessel at anchor I should pass round the lower light.
37. How far may the nets of a drift net fishing vessel extend to
windward ?
Any distance up to 3 of 4 miles.
38. If unable to pass on the side of the high light of a drift net
fisherman what would you do?
I should have to pass on the other side, that is to windward. When
bringing the lights in line I should stop the engines and cross the warp at
a fair speed. There would then be less danger of fouling it with the
propeller than there would be if I kept the engines turning.
204
NIOHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
QUESTIONS RELATING TO FOG SIGNALS, ETC
Articles 15 and 16.
1. What sound-signalling apparatus are steam vessels required to be
provided with?
(i) An efficient steam whistle or siren sounded by steam or some
substitute for steam, and so placed that the sound will not be intercepted
by any obstruction.
(ii) An efficient fog horn to be sounded by mechanical means.
(iii) An efficient bell.
2. What are sailing vessels of 20 tons gross tonnage and upwards
required to have?
A fog horn and bell similar to those required for steamships.
3. When are the signals described in Art. 15 to be used?
In fog, mist, falling snow, or heavy rain storms, whether by day or
night.
4. You hear one prolonged blast of a steam whistle or siren; what does
that denote?
The presence of a steamship having headway.
5. Suppose you hear two prolonged blasts with an interval of about
1 second between?
It would be a steam vessel under way but stopped, having no head¬
way.
6. How often are steam vessels under way required to repeat their fog
signals?
At intervals not exceeding 2 minutes.,
7. How often are sailing vessels and vessels at anchor required to give
their fog signals?
At intervals not exceeding 1 minute.
*
8. You hear a prolonged blast followed by two short ones; what does
that indicate?
The presence of a vessel towing another; a vessel employed in laying
or picking up a telegraph cable; a vessel not under command or unable
to manoeuvre in accordance with the Rules; a vessel being towed may
also give this signal, but must not give any other.
SHIPS’ LIGHTS AND REGULATIONS
205
9. If you were under way in either a sailing ship or steam
you encountered fog or mist, etc., what would you do
comply with the Regulations?
I should at once commence giving the required fog signal, and go at
a moderate speed, having careful regard to existing circumstances and
conditions. I should also keep an efficient lookout, and bear in mind
Art. 29.
10. If the vessel you are in is a steamship, what further precaution are
you required to take if you hear apparently forward of your
beam the fog signal of another vessel, the position of which is not
ascertained?
ks far as the circumstances of the case permit I must stop my engines,
and then navigate with caution until danger of collision is over.
11. Describe the fog signals to be given by fishing vessels.
* If of 20 tons gross tonnage or upwards, they shall at intervals of
not more than 1 minute make a blast; if steam vessels with the whistle
or siren, and if sailing vessels with the fog horn, each blast to be followed
by ringing the bell.
12. What sound signal must sailing vessels and boats of less than 20
tons gross tonnage make?
If they do not give the signal prescribed for larger vessels, they
must make some other efficient sound signal at intervals of not more
than 1 minute; this applies to both ordinary and fishing vessels.
13. What is the daymark for a vessel at anchor?
A black ball forward at some ports, but it is not international.
14. What is the day signal for a vessel aground in or near a fairway?
Only such signal as the Port Authority may direct.
15. What is the fog signal for a vessel at anchor over 350 feet in length?
Ring the bell forward every minute.
16. What fog signal is given by a vessel being towed?
The same as the towing vessel, viz., a prolonged blast followed by
two short blasts.
17. What is the fog signal for a vessel aground in a fairway?
m m
None specified but ring the bell every minute to attract attention*
When being approached by another vessel sound also the Morse
letter U (*-—) meaning “You are standing into dangerSee page 625.
CHAPTER X.
STEERING AND SAILING RULES;
Preliminary—Risk of Collision.
Articles 17 to 31 Must be Learned Word for Word.
(Begin Now and Memorise One Article at a Time.)
Risk of collision can, when circumstances permit, be ascertained by
carefully watching the compass bearing of an approaching vessel.
If the bearing does not appreciably change, such risk should be deemed
to exist.
Sailing Vessels approaching one another.
Art. 17.—When two sailing vessels are approaching one another,
so as to involve risk of collision, one of them shall keep out of the way
of the other, as follows, viz.:—
(а) A vessel which is running free shall keep out of the way
of a vessel which is close-hauled.
(б) A vessel which is close-hauled on the port tack shall keep
out of the way of a vessel which is close-hauled on the starboard
tack.
(e) When both are running free, with the wind on different
sides, the vessel which has the wind on the port side shall keep
out of the way of the other.
(d) When both are running free, with the wind on the same
side, the vessel which is to windward shall keep out of the
way of the vessel which is to leeward.
(e) A vessel which has the wind aft shall keep out of the
way of the other vessel.
Steam Vessels meeting end on.
Art. 18.—When two steam vessels are meeting end on, or nearly
end on, so as to involve risk of collision, each shall alter her course to
starboard, so that each may pass on the port side of the other.
This Article only applies to cases where vessels are meeting
end on, or nearly end on, in such a maimer as to involve nsk of
206
THE REGULATIONS FOR PREVENTING COLLISIONS AT SE.A 207
collision, and does not apply to two vessels which, must, if both
keep on their respective courses, pass clear of each other.
The only cases to which it does apply are when each of two
. vessels is end on, or nearly end on, to the other; in other words,
to cases in which, by day, each vessel sees the masts of the other
in a line, or nearly in a line, with her own; and, by night, to cases
in which each vessel is in such a position as to see both the side¬
lights of the other.
It does not apply, by day, to cases in which a vessel sees
another ahead crossing her own course; or by night to cases where
the red light of one vessel is opposed to the red light of the other,
or where the green light of one vessel is opposed to the green
light of the other, or where a red light without a green light, or a
green light without a red light, is seen ahead, or where both
green and red lights are seen anywhere but ahead.
Two Steam Vessels Crossing.
Art. 19.—When two steam vessels are crossing, so as to involve
risk of collision, the vessel which has the other on her own starboard
side shall keep out of the way of the other.
Steam Vessel and Sailing Vessel.
Art. 20.—When a steam vessel and a sailing vessel are proceeding
in such directions as to involve risk of collision, the steam vessel shall
keep out of the way of the sailing vessel."
Course and Speed.
Art. 21.—Where by any of these Rules one of two vessels is to keep
out of the way, the other shall keep her course and speed.
Note. —When, in consequence of thick weather or other causes,
such vessel finds herself so close that collision cannot be avoided by
the action of the giving-way vessel alone, she also shall take such action .
as will best aid to avert collision. (See Articles 27 and 29.)
Avoid Crossing Ahead.
Art. 22.—Every vessel which is directed by these Rules to keep
out of the way of another vessel shall, if the circumstances of the case
admit, avoid crossing ahead of the other.
208 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Slacken Speed, Stop or Reverse.
Art. 23. —Every steam vessel which is directed by these Rules to
keep out of the way of another vessel shall, on approaching her, if
necessary, slacken her speed or stop or reverse.
f
Overtaking Vessel.
Art. 24. —Notwithstanding anything contained in these Rules, every
vessel, overtaking any other, shall keep out of the way of the overtaken
vessel.
* Every vessel coming up with another vessel from any direction
more than two points abaft her beam, i.e. y in such a position,
with reference to the vessel which she is overtaking, that at
night she would be unable to see either of that vessel’s side-lights,
shall be deemed to be an overtaking vessel; and no subsequent
alteration of the bearing between the two vessels shall make the
overtaking vessel a crossing vessel within the meaning of these
Rules, or relieve her of the duty of keeping clear of the overtaken
vessel until she is finally past and clear
As by day the overtaking vessel cannot always know with certainty
whether she is forward or abaft this direction from the other vessel,
she should, if in doubt, assume that she is an overtaking vessel and keep
out of the way.
Keep to Starboard Side of Fairway.
Art. 25.—In narrow channels every steam vessel shall, when it is
safe and practicable, keep to that side of the fairway or mid-channel
which lies on the starboard side of such vessel.
^ Sailing Vessels and Fishing Boats.
Art. 26. —Sailing vessels under way shall keep out of the way of
sailing vessels or boats fishing with nets, or lines, or trawls. This
Rule shall not give to any vessel or boat engaged in fishing the right
of obstructing a fair-way used by vessels other than fishing-vessels or
boats.
Avoiding Immediate Danger.
Art. 27. —In obeying and construing these Rules due regard shall
be had to all dangers of navigation and collision, and to any special
circumstances which may render a departure from the above Rules
necessary in order to avoid immediate danger.
THE REGULATIONS POR PREVENTING COLLISIONS AT SEA 209
Sound Signals for Vessels in Sight of one Another.
Art. 28.—The words “short blast” used in this Article shall mean s
blast of about 1 second’s duration.
When vessels are in sight of one another, a steam vessel under
way, in taking any course authorised or required by these Rules, shall
indicate that course by the following signals on her whistle or siren,
viz :—
One short blast to mean* “I am directing my course to
starboard.”
Two short blasts to mean, “I am directing my course to
port ”
Three short blasts to mean, “My engines are going full speed
astern.”
No Vessel under any Circumstances to Neglect Proper Precautions.
Art. 29.—Nothing in these Rules shall exonerate any vessel, or
the owner, or master, or crew thereof, from the consequences of any
neglect to carry lights or signals, or of any neglect to keep a proper
look-out, or of the neglect of any precaution which may be required by
the ordinary practice of seamen, or by the special circumstances of the
case.
Reservation of Rules for Harbours and Inland Navigation.
Art. 30.—Nothing in these Rules shall interfere with the operation
of a special rule, duly made by local authority, relative to the navigation
of any harbour, river, or inland waters.
Distress Signals.*
Art. 31.—When a vessel is in distress and requires assistance from
other vessels or from the shore, the following shall be the signals to be
used or displayed by her, either together or separately, viz .:—
Note .—The use of any of the above signals, exceptforthe purpose of indicating
that a vessel is in distress, and the nse of any signals which may be confused
with any of the above signals, is prohibited:
* If a master of a vessel uses or displays, or causes or permits any person
under his authority to use or display, any of those signals of distress, except
in the case of a vessel being in distress, he shall be liable to pay compensation
for any labour undertaken, risk incurred, or loss sustained in consequence of
that signal having been supposed to be a signal of distress, and that com¬
pensation may without prejudice to any other remedy, be recovered in the
same manner in which salvage is recoverable. (Merchant Shipping Act,
1894, section 434 (2).)
210 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
In the daytime—
1. A gun or other explosive signal fired at intervals of about
a minute;
2. The International Code signal of distress;
3. * The distant signal, consisting of a square flag, having
either above or below it a ball or anything resembling a ball;
4. A continuous sounding with any fog-signal apparatus;
5. The international distress signal made by radio -
telegraphy or radiotelephony, or by any other distant signalling
method.
At night—
1. A gun or other explosive signal fired at intervals of about
a minute;
2. Flames on the vessel (as from a burning tar-barrel, oil-
barrel, etc.);
3. Rockets or shells, throwing stars of any colour or
description, fired one at a time, at short intervals;
4. A continuous sounding with any fog-signal apparatus;
5. The international distress signal made by radiotelegraphy
or radiotelephony, or by any other distant signalling method.
The use of any of the above signals, except for the purpose of indi¬
cating that a vessel is in distress, and the use of any signals which
may be confused with any of the above signals, is prohibited.
THE STEERING AND SAILING RULES
Articles 17 to 27.
These Articles form the most difficult part of the Regulations for
beginners. A knowledge of the preceding ones depends in a great
measure upon the memory, but the Steering and Sailing Rules appeal
more to your intelligence and knowledge of seamanship. They there¬
fore demand special attention in order that you may he able to apply
them readily and promptly whenever occasion to do so arises.
Risk of Collision.—The preliminary paragraph on Risk of Collision
is of great importance, as it shows how you may ascertain—when circum¬
stances permit—if risk of collision exists between approaching vessels.
*A further distress signal is provided in the ‘‘International Code of Signals."
It is a distant signal consisting of a cone point upwards, having either above
or below it a ball, or anything resembling a ball. This signal has not been
sanctioned by Order in Council under the provisions of section 434 of the
^Merchant Shipping Act, 1834
STEERING AND SAILING RULES
211
To be practical we must not expect to be able, under the varying condi¬
tions arising at sea, to treat the -Rules with mathematical exactness. We
can, however, establish one or two general principles which, properly
appreciated, will afford valuable help to beginners. A diagram and
explanation will show the truth of the preliminary paragraph.
Suppose A and B to be two vessels approaching each other in the
directions A 0 and B 0 respectively. Their courses cross at C, and if
they both reach this point at the same time a collision must occur If
they are proceeding so as to reach the point C together their speeds must
be proportional to their respective distances from G. Thus, m the dia¬
gram, A being the farther vessel from the collision point, her speed must
be proportionally greater than that of B to cause her to reach C at
the same time. Assuming that this is the case; when A has sailed
one-third of her distance from 0 and is at A lf B will also have sailed one-
third of her distance from O and will be at also when A has completed
half her distance from O and is at A 2 , B will have covered half her
distance from € and will be at B 2 , and so on.
If lines aTe drawn joining these corresponding positions, it will be
seen that they are parallel, thus showing that the bearings of the two
vessels from each other would not appreciably alter if they were
approaching in such a manner as to involve risk of collision.
If you see both side-lights of another vessel in any direction, your
own vessel is in the act of passing the collision point. Also it is dear
212
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
that if you see a side-light of another vessel ahead, the positions are
reversed, and the other vessel is in the act of crossing. Unless the
vessels are near each other, there is very little risk of collision m these
two cases, but care should be taken in the vessel having the other ahead
not to deviate from her course towards the direction in which the other
vessel is heading.
Again, if the bearing of a light does not change appreciably, it not
only shows that risk of collision exists, but it also gives a hint as to
the probable direction in which the other vessel is heading. It may be
stated as a general rule that the broader a light bears on the bow th
0(3
Fig. *.
farther away must be the point of collision. Suppose you see, about
a point on the bow, the side-light of another vessel crossing, and let
us assume, for the purpose of illustration, that both vessels are going 10
miles an hour, that they are 2 miles apart, and are proceeding in such
lirections as to involve risk of collision. The point of collision would
be about 1 mile away, and would be reached (assuming that each
vessel kept her course and speed) in about 6 minutes. Had the light
3een about 4 points on the bow, the collision point would have been
dxmt 1£ miles away, and would have been reached in about 9 minutes.
STEERING AND SAILING RULES
213
If it had been 6 points on the bow, the point of collision would have
been 2J miles away, and have been reached in 15 minutes. This is
illustrated in the annexed diagram.
A, B } and C are vessels 1 point, 4 points, and 6 points on the bow
respectively. A v B Xi and G 1 the respective points of collision with D,
assuming each one to be going at the same speed as Z>.
Of course at sea you never know the speed of the other vessel, but
the foregoing is useful, and points out that when it is your duty to keep
out of the way of another vessel the more nearly she is ahead of you the
greater is the need for prompt action. Also, when a light bears nearly
ahead, and it is your duty to “keep out/’ it is hardly necessary to wait
to see if the bearing alters, as a slight change of your course in the right
direction will convert the position into one of safety.
Bo far no notice has been taken of the lengths of vessels. This is a»
important factor, and one which must be considered. Its importance
rapidly increases as vessels near each other. In order to avoid collision,
the whole length of one vessel must pass clear of the crossing point
before the stem of the other reaches it; therefore, not only must the
^bearing change but it must change appreciably , otherwise risk of collision
must be deemed to exist. You must use your own judgment as to what
constitutes an appreciable change of bearing.
Notice also the words^ “when circumstances permit,” as cases may
arise where it may be advisable and necessary for the giving-way vessel
to act immediately and not to wait to see if the bearing alters.
Avoiding Collision.—Articles 21, 22 and 23 deal more particularly
with the avoidance of collision. Article 22, and also common sense,
require that the vessel which has to keep out of the way shall, if circum¬
stances permit, avoid crossing ahead of the other—the latter being
required (by Article 21) to keep her course and speed except in special
cases. (See Note, Art. 21.)
Refer to Figure 3 which is intended to represent four ships on con¬
verging courses and heading for a common collision point. Assume
yourself to be in ships A, B, G and D in turn with only one of the
other three vessels in sight, that is, cover any two of the vessels with
your hand and state what you would do if there was risk of collision
with the third vessel, assuming there is room to manoeuvre.
In Ship A .— (1) Keep clear of B (Art. 19). I would alter course
to starboard and go under his stern, or, if very
close I would slow down or stop and let him
214 NICHOLLS’S SEAMANSHIP ANI) NAUTICAL KNOWLEDGE
pass ahead of me {Article 23), or, alter course
to port.
(2) Alter course to starboard for C (Article 1&JL
(3) Stand on for D .
In Ship B —(1) Keep clear of G.
$) Stand on for B
(3) Stand on for A,
Fig. 3.
In Ship C —(1) Keep clear of D .
(2) Alter course to starboard for A
(3) Stand on for B.
In Ship B —(1) Keep clear of A.
(2) Keep clear of B.
(3) Stand on for G
3TEERING AND SAILING RULES
215
Articles 18 and 19.
You are m a steam vessel, what would you do in each of the following
cases assuming there is risk of collision ?
1. You see the side-lights and masthead lights of another steam vessel
ahead?
Alter my course to starboard (Art. 18), because we are meeting end
on, and give one short blast on the whistle (Art. 28).
2. Red light and masthead lights of a steamship on your starboard bow?
Keep out of her way (Art. 19) I would alter course to starboard
to go under her stern (Art. 22) and give one short blast (Art. 28) If too
close to go under her stem I would alter course to port, and give two
short blasts. If dangerously close I would stop the engines and reverse
(Art. 23).
3 A steamship’s green and masthead lights on your port bow?
Stand on (Art. 19), and keep my course and speed (Art. 21).
4 A steam vessel’s red and masthead lights about 4 points on your star¬
board bow, and as you are watching the bearing of the red
light, a green light appears about 2 points on the bow; what
would you do, assuming that the bearing of the red light is not
changing appreciably?
The green light is that of a passing vessel. I should wait until
the green light had altered its bearing to about 6 points or so on the bow,
and then keep out of the way of the red. If I found it necessary I should
slacken speed or stop my engines.
Questions on the remaining Steering and Sailing Rules.
Articles 20 to 27.
1. If a steam vessel and a sailing vessel are approaching each other so
as to involve risk of collision, which vessel is required to keep
out of the way?
The steam vessel. (Art. 20.)
2. Are there any special cases where the sailing vessel would have to keep
out of the way'of the steam vessel?
Yes. If the sailing vessel was overtaking the steamer; or if the
. steamer was engaged in laying, picking up, or repairing a telegraph cable;
or if the steamer was not under command.
216
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
3 Where, by the Rules, one of two vessels is required to keep out of the
way, what is the other required to do?
To keep her course and speed. (Art. 21.)
4 Is there any qualification or exception to this?
Yes. The note attached to Article 21 says that when, in con¬
sequence of thick weather or other causes, two vessels are so close that
collision cannot be avoided by the action of the giving-way vessel
alone, the other shall take such action as will best aid in averting a
collision; also
Article 27 says due regard must be had to all dangers of navigation
and collision, and to any special circumstances which may render a
departure from the Rules necessary in order to avoid immediate danger;
also
Article 29 says, nothing in these Rules shall exonerate any vessel* or
the owner, or master, or crew thereof, from the consequences arising
from the neglect of any precaution required by the ordinary practice
of seamen or the special circumstances of the case.
5 Suppose a vessel is approaching you so as to involve risk of collision,
and that it is your duty to “keep out of the way,” do the
Regulations specify what action you must take?
No It is left to myself to decide what action must be taken to
avoid collision, but the Rules state that if circumstances admit I must
avoid crossing ahead of the other vessel (Art. 22); also, if I am in a steamer
I must if necessary slacken speed, or stop, or reverse. (Art. 23.)
Note that there is one exception in this case When two steam vessels
are meetmg end on, or nearly end on, so as to involve risk of collision, each
S all .5J ter to s^board, so that each may pass on the port side of
the other. (Art. 18.)
6. Are sailing vessels under way required to keep out of the way of filing
vessels and boats engaged in fishing?
Yes. They must keep out of the way of sailing vessels or boats
fishing with nets or lines or trawls. (Art. 26.*)
7. When one vessel is overtaking another, which is required to keep out
of the way?
The overtaking vessel. (Art. 24.)
* Note that this Article does not require sailing vessels.to keep clear of
sUam fishing vessels. They are, however, hampered by their trawl and unable
to manoeuvre m the same way as ordinary steamers. It is the ordinary practice .
&sn , „'s“isnso ,ok “ p “‘ o, * 1, *- !r ' ****.&**.
STEERING AND SAILING BULKS
217
8. Is there a ny exception to this rule?
No. For Article 24 says, Notwithstanding anything contained in
these Buies, every vessel overtaking any other shall keep out of the way
of the overtaken vessel.”
9. Are you required to depart from the Steering and Sailing Rules in
any particular case?
Yes. But only when special circumstances render a departure
necessary in order to avoid immediate danger. (Art. 27.)
10 You are in a steamer and you see two other steam vessels, one on
your port bow, the other on your starboard bow, and both are
approaching so as to involve risk of collision; what would you do?
I should keep out of the way of the one on my starboard side;
the other vessel has to keep out of my way. (Art. 19.)
11. But would you not then be departing from the Rule which requires
you to keep your course and speed for the one on your port bow?
Yes; but I should consider this a special case in which, by Article 27,
I was required to depart from that Rule in order to avoid collision
with the one on the starboard bow.
12. When a steam vessel takes any course authorised or required by the
Regulations, must she indicate that course to the other vessel or
vessels?
Yes (Art. 28), but only when the vessels are in sight of each other.
13. How must she indicate what course she is taking?
By signals on the whistle or siren.
1 short blast means—“I am directing my course to starboard.”
2 short blasts mean—“I am directing my course to port.”
3 short blasts mean—“My engines are going full speed astern.”
/
14. Has a steamer towing another vessel any right of way not usually
allowed to other vessels?
No. She must follow the ordinary Rule of the Road for steamers.
15. In what waters or seas are vessels required to follow the Regulations?
Upon the high seas and in all waters connected therewith navigable
by seagoing vessels, but nothing in the Rules shall interfere with the
operation of a special rule duly made by local authority relative to the
navigation of any harbour, river, or inland waters. (Preliminary
to Articles.)
, i
2i8
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
16. A green light overhauls you on your port side and then attempts to
cross ahead. What would you do? \
As she is the overtaking vessel she must keep clear of me until
she is finally past and clear. (Art. 24). I must keep my course and speed.
{Art. 21.) At the same time I must observe the footnote to Article 21,'
and if she gets too near me to avoid collision by her own action 1 should
also take action as would best help her to do so. ’ Probably that would
be “full speed astern,” 3 short blasts. Look out for anything that
might be coming up behind me.
17. You are in a steam vessel and you sight the red light of a sailing
vessel on your port bow. What would you do?
We are passing ships and will most likely go clear of each other.
If she was to windward of me and was in ballast, or if it was blowing
hard, she might be sagging down to leeward towards me. I should
watch her bearing carefully and if it did not change appreciably should
alter my course to starboard to get out of her way. Should give her
1 short blast. (See Arts. 27. 28, and 29 )
HOW IS SHE HEADING T
221
TO FIND OUT HOW ANOTHER VESSEL IS HEADING.
A vessel’s side-lights are screened to show the light from right ahead
to 2 points abaft her beam (See further note on screening of side-lights,
page 256.)
When the side-light of another vessel is cut off from view, or is
just coming into sight, it indicates that the observer is bearing 2 points
abaft her beam. From this information the direction in which the
other vessel was heading at the moment can be ascertained as follows:—
A Red light just being shut out will indicate that the vessel carrying it
was heading 6 Points to the Left of its bearing, because red is the
left hand light.
A Green light being just shut out will indicate that the vessel
carrying it was heading 6 Points to the Right of its bearing, because
green is the right hand light.
The rule has nothing whatever to do with the direction the observer’s
vessel is heading, unless the bearing of the other ship is given as so
many points on the bow, when, of course, he must know how his vessel
is heading in order to get the bearing of the light.
In Diagram 1 the observer must imagine himself to be in the centre
of the compass, which represents the centre of his horizon, and that the
side-light of each of the vessels Nos. 1 to 6 is just being shut out on the
respective bearings as indicated, it is required to know how each vessel
was heading.
1. Green light shut out when bearing North?
J3ix points to right of the bearing—R.N.E.
2. Red light shut out when bearing N.E.?
Six points to left of the bearing—N.N.W.
3. Green light shut out on an E.S.E. bearing?
She is heading South.
4. Red light disappears on a S.S.E. bearing?
She is heading East.
5. Green light disappears on a S.W. bearing?
She is heading W.N.W.
6 . Red light shut out when bearing W.N.W.?
She is heading S.W.
m
NICTOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Diagram 2
The bearing of a side-bght on a given bearing, between what points of
the compass may the vessel be heading ?
HOW IS SHIS HEADING-/
223
The observer is supposed to be standing at the centre of the compass,
shown in Diagram 2, which is also the centre of his horizon, the points
of the compass radiating outwards towards the sea horizon. There are
five examples given and it is required to know, in each case, between
what points the other vessel is heading when one of her side-lights is
sighted on a given bearing. Let us discuss each example separately.
1. A . Both side-lights bearing North? The vessel can only be
heading South.
B Green light bearing North. When the vessel turns her head to
port from position A she shuts out her red light; the observer
will see only her green light until she has swung through 10
points, that is, when she heads E.N.E., for then the observer will
be 2 points abaft her beam and the green light will then disappear.
Buie .—Count 6 points to Starboard of the bearing for a Green light,
or, 6 points to Port of the bearing for a Red light, and the vessel will be
heading somewhere between that direction and the Bearing Reversed
nearly.
The green light was bearing North? The vessel is heading between
E.N.E. and almost South.
0 Red light bearing North? The vessel is heading between W.N.W.
and almost South.
When the vessel’s head turns to starboard from position A the green
light is shut out and the observer will see only her red light until
she has swung through 10 points, that is, when she is heading
W.N.W., then it will disappear as the observer will then be 2
points abaft her beam.
2 A. Both side-lights bearing E.N.E.? The vessel is heading W.S.W*
B. Green light bearing E.N.E.? The vessel is heading between
, S.E. and W.S.W. nearly.
(7. Red light bearing E.N.E.? The vessel is heading between North,
and W.S.W. nearly.
3. A. Both side-lights bearing S.E.? The vessel is heading N.W.
Turn the book round and look outwards from the centre of the
compass towards the light.
B. Green light bearing S.E.? She is heading between S.S.W. and
N.W. nearly.
<7. Red light bearing S.E,? She is heading between E.N.E. and
N.W.
224
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
4. A. Both side-lights bearing S.W.? She is heading N.B.
B . Green light bearing S.W.? She is heading between W.N.W and
N.B.
C. Bed light bearing S.W.? She is heading between S.S.E. and N.E.
6. A. Both lights bearing W N.W.? She is heading E.S E.
B . Green light bearing W.N.W.? She is heading between North
and E.S.E.
C. Bed light bearing W.N.W.? She is heading between S.W. and
E.S.E.
The angle of parallax subtended by the two masthead lights of a
steamship gives a good idea of the direction she is heading. When one
light is vertically over the other she is approaching end on; when the
lower light is to the right of the higher one she is crossing over to star¬
board and when the lower light is to the left of the higher one she is
cxossmg over to port.
A square-rigged vessel cannot head closer to the direction of the
wind than 6 points, that is to say, the wind is 6 points on her starboard
bow when she is on the starboard tack and 6 points on her port bow
when she is on the port tack, so that there is always an arc of the horizon
of 12 points on which she cannot make headway. ’
A sailing vessel in fog gives One blast when on the Starboard ta^k;
Two Blasts when on the Port tack, and Three blasts when she has the
wind Abaft the Beam. She gives the close-hauled signal when the wind
is exactly abeam, and when changing from one tack to the other she
continues to give the fog signal for the last tack she was on until she
has headway on her new tack.
.. ? r
(i) (n)
!<m)
\
IV)
Fig. 4.
Examples —in fog—
(i) Wind North, a sailing vessel giving 1 blast, how is she heading!
W.N.W.
(ii) Wind North, a sailing vessel giving 2 blasts; how is she heading?
E.N.B.'
Wind North, a sailing vessel giving 3 blasts; how is she heading?
From East to West by way of South.
HOW IS SHE HEADING f
225
(iii) Wind E.S.E., sailing vessel giving 2 blasts? She is heading
South.
(iv) Wind N.W. by N., sailing vessel giving 1 blast? She is heading
W. by S.
(v) Wind W.S.W., sailing vessel giving 2 blasts? She is heading
N.W.
Wind W.N.W.. sailing vessel giving 3 blasts? She is heading
anywhere between N.N.E. and S.S.W. by way of East.
Exercise I,
How is the other vessel heading in the following examples for
exercise? These should be worked out with the help of a compass
card.
1. A green side-light shut out when bearing (i) N.W., (li) W.S.W.,
(iii) S. by W., (iv) S.E., (v) E.N.E., (vi) N.E. by N.
2. A red side-light shut out when bearing (i) N. by E., (ii) E. by S.,
(iii) South, (iv) S.S.W., (v) West, (vi) N.W. by N.
3. Heading N.N.E., a red side-light disappears when bearing 2
points abaft the port beam?
4. Heading S.E., a red side-light disappears when bearing 3 points
on the starboard bow?
5. Heading E. by N., a green light disappears when bearing 2 points
on the port bow?
6. Heading S.W. by S., a red light disappears when bearing 2 points
abaft the starboard beam?
Exercise II.
Between what 10 points may the other vessel be heading in the
following exercises.
1. A green side-light bearing (i) N.E., (ii) E.S.E., (iii) S.S.W.,
(iv) N.W. by N.?
2. A red side-light bearing (i) N.N.E., (ii) S.S.E., (iii) W.S.W.,
(iv) N.N.W.?
3. Heading N.W,, a green side-light is sighted 2 points on the
starboard bow, between what points may she be heading?
4. Heading S. by W., a green side-light is sighted 4 points on the
port bow, between what points may she be heading?
1 *
226 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
5. Heading W.N.W., a red side-light bears 2 points on the port bow,
between what points may she be heading?
6. Heading S.E. by S., a red side-light is sighted 4 points on the
starboard bow, between what points may she be heading?
Exercise III.
You are in a steamship; state between what points the sailing
vessels in the following examples may be heading, making due allowance
for the direction of the wind.
1 .
Side-light
Green
Bearing
S.W.
Wind.
South
2.
es.e:
N.W.
3.
»
EN.E.
S.S.E.
4.
Bed
S.E.
North
5.
tt
S.S.W.
S.E
6.
tt
W.S.W.
N.W.
7. You are heading North The wind is right aft. You see a
green light ahead. How is that ship steering?
8. You are heading North, with a S.E. wind. You see a green light
ahead. - How is that ship steering?
9. You are heading South. Wind North. You see a red light
ahead. How is the other ship heading?
10. You are heading South. Wind N.E. You see a red light ahead.
How is the other ship heading?
11. You are heading N.E. with the wind West. You see a green
light ahead. Between what points is that vessel steering?
12. You are heading N.N.E. with the wind South. You see a green
light 2 points on starboard bow. How is the other vessel steering?
13. You are heading S.E. .with the wind right ahead, and you see a
sailing vessel’s red light 4 points on your starboard bow. Between
what points is she steering?
Answers—Exercise IJ
1. (i) N.N.E., (ii) N.W., (iii) W. by S., (iv) S.S.W., (v) S.E (vi)
E. by S. ,
2. (i) N.W. by W., (ii) N.E. by N., (iii) E.S.E., (iv) S.E., (v) SAW.
(vi) W. by S.
„ 3. S.S.W. 4. E. by S. 5. S.E. by E. 6. W. by S.
HOW IS SHE HEADING!
227
Exercise II.
1. (i) E.SE. to S.W. nearly, (ii) South to W.N.W. nearly, (iii)
West to N.N.E. nearly, (iv) N.E. by N. to S.E. by S. nearly.
2. (i) N.W. to S.S.W. nearly, (ii) E. to N.N.W. nearly, (iii) South
to E.N.E nearly, (iv) West to S.S.E. nearly.
3. KE. to S.S.E.
4. S.W. by S. to N.W. by N.
5. S.S.W. to E.
6. S.E. by E. to N. by E.
Exercise III.
1. W.N.W. to N.E. Free to port, wind aft or free to starboard.
2. W.S.W. to South. Free to starboard.
3. S.W. to W.S.W. Close-hauled to port.
4. E.N.E. Closed-hauled to port.
5. E.N.E. to N.N.E. Close-hauled to starboard or slightly free to
starboard.
6. South to E.N.E. Free to port, wind aft or free to starboard.
7. E.N.E. to E.S.E. She may have the wind from 2 points before
the starboard beam to 2 points abaft the beam.
8. E.N.E. Close-hauled to starboard.
9. E.N.E. to E.S.E. She could have the wind from 2 points abaft
her port beam to 2 points before her beam.
10. E.S.E. Close-hauled to port.
11. E.S.E. to S.S.W. Free to starboard or close-hauled to star¬
board.
12. E.S.E. Close-hauled to starboard.
13. E.N.E* to N. Free or close-hauled to starboard.
AA KJkl
228
NTCHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
10
HOW IS SHE HEADING?
Diagram 3 represents a steamship heading North with the wind
from South, right aft. Discuss the respective lights of the sailing vessels
on the bearings as indicated, how the vessels may be heading, how they
are carrying the wind and what action the steamship should take if
there were risk of collision.
1. The wind being from South the prohibited courses for a sailing
vessel lie between E.S.E. and W.S.W., that is 6 points on each side
of the wind.
The green light ahead indicates a sailing vessel heading between
E.N.E. and E.S.E. She cannot lie closer to the wind than 6 points, viz.,
E.S.E. She may be close-hauled to starboard, or she may have the
wind a little abaft her beam depending on how she is heading.
The red light ahead indicates a vessel heading between W.N.W. and
W.S.W. She may be close-hauled to port, or slightly free with the
wind a little abaft her port beam.
2. The red light 4 points on my starboard bow indicates a sailing
vessel heading between W.S.W. and N.N.W. She is either close-hauled
to port, or free to port.
J$. The red light on my starboard beam indicates a vessel heading
between West and N.N.W., she is free to port.
4. The green light 4 points on my port bow indicates a vessel heading
between E.S.E. and N.N.E., she cannot lie closer to the wind than E.S.E.
She is either close-hauled to starboard, or free to starboard.
5. The green light on my port beam is that of a sailing vessel heading
between East and N.N.W., free to starboard.
If the lights keep on the same bearing there is risk of collision.
I would give 1 blast and alter course to starboard and pass under
the stem of the red lights on my starboard bow, and for the green lights
on my port bow I would alter course to port and give 2 blasts. ^
WNW
230
NICHOLLS 8 SEAMANSHIP AND NAUTICAL KNOWLEDGE
HOW IS SHE HEADING?
231
Diagram 4 represents a steamship heading North with the wind
from North, right ahead, and a sailing vessel ahead showing both her
side-lights, or her green light, or her red light. We wish to discuss
between what points she may be heading, how she is carrying the
wind, and what action the steamship should take if there were risk
of collision.
1. When the wind is North the prohibited courses for a sailing
vessel lie between E.N.E. and W.N.W.
When she is showing both side-lights she is heading South with the
wind right aft.
When showing her green light only she is heading somewhere between
E.N.E. and South. She is either free with the wind on her port quarter,
or close-hauled to port.
When showing her red light only she is heading somewhere between
W.N.W. and South, and is either free with the wind on her starboard
side, or close-hauled to starboard.
2. Her red light 4 points on my starboard how would indicate
that she is heading between S.W. and W.N.W., close-hauled to starboard,
or she may have the wind a little abaft her starboard beam.
3. Her red light on my starboard beam would indicate she is heading
between West and W.N.W., close-hauled to port.
4. Her green light 4 points on the port bow indicates she is heading
between S.E. and E.N.E. so that she is either close-hauled to port,
or running with the wind free a little abaft her port beam.
5. Her green light on my port beam indicates she is heading between
East and E.N.E., close-hauled to port.
When a light keeps on the same hearing there is risk of collision, and
should this he imminent I would alter course to starboard for a red
light on my starboard bow and give 1 blast. Alter course to port fox
a green light on my port bow and give 2 blasts.
232
NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Diagram 5.
Wind on starboard beam, Steamship meeting a sailing vesseL
HOW IS SHE HEADING?
233
Diagram 5.—You are in a steamship heading North, wind East,
discuss how the respective sailing vessels in the diagram showing you
their red or green side-lights may be carrying the wind.
When the wind is East the prohibited courses for sailing vessels lie
between N.N E. and S.S.E., 6 points on either side of the direction of
the wind.
The sailing vessels showing a red light on any bearing on the star¬
board bow are not restricted and can sail in any direction within the
full 10-point arc of their red light. They are running free with the
wind either on their port quarter, right aft, or on their starboard quarter
as indicated by the wind arrows.
A vessel showing her green light on my port bow cannot take advant¬
age of the full 10-point arc of her green light as she would then be heading
within 6 points of the wind.
1. The vessel showing both her red and green lights 2 points on my
port bow can only be heading S S.E., close-hauled on the port tack.
2. The vessel showing her green light 4 points on my port bow can
only be heading N.N.E., close-hauled on the starboard tack.
3. The vessel showing her green light 6 points on my port bow can
only head between N.N.E. and N., close-hauled on the starboard tack.
• *
4. The vessel showing her green light on my port beam can only
be heading between N.N.E. and N.N.W. She may be close-hauled on
the starboard tack, or have the wind a little abaft her starboard beam.
If a sailing vessel’s red light on' my starboard bow does not alter its
bearing there is risk of collision. I would alter course to starboard
and give 1 short blast.
If a sailing vessel’s green light on my port bow does not alter its
bearing there is risk of collision. In this example we are, however, on
slightly converging courses and approaching each other slowly. I
could give 2 blasts, alter Course to port and pass under her stem; or
if I were close to her and passing I could give 1 blast, alter course to
starboard and when finally passed and clear resume my course.
I would alter course to starboard for the red and green lights ahead
and ,also for the red and green lights 2 points on my port bow.
234
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
I
Diagram 6.
Wind on port beam. Steamship meeting a sailing vessel.
HOW IS SHE HEADING?
235
_ t
Diagram 6.—You are in a ship heading North, wind West, discuss
how the respective sailing vessels in the diagram showing their red or
green side-lights may be carrying the wind.
When the wind is West the prohibited courses for sailing vessels lie
between N.N.W. and S.S.W.
The sailing vessels showing a green light on any bearing on my port
bow are not restricted and can be sailing in any direction within the
full 10-point arc of their green light. They are running free with the
wind either on their port quarter, right aft, or on their starboard quarter
as indicated by the wind arrows.
A vessel showing her red light on my starboard bow cannot take
advantage of the full 10-point arc of her red light as she would then be
heading within 6 points of the wind.
1. The vessel showing both her red and green lights 2 points on my
starboard bow can only be heading S.S.W., close-hauled on the star¬
board tack.
2. A vessel showing her red light 4 points on my starboard bow
can only be heading N.N.W., close-hauled on the port tack.
3. A vessel showing her red light 6 points on my starboard bow
can only head between N.N.W. and North, close-hauled on the port
tack.
4. A vessel showing her red light on my starboard beam c$n only
head between N.N.W. and N.N.E. She may be close-hauled on the
port tack, or have the wind a little abaft her port beam.
Assuming any one of the sailing vessels’ lights shown in the diagram
to keep on the same bearing, there would be risk of collision and I have
to keep clear.
I would, give 2 blasts and alter course to port for a green light on
my port bow.
I would alter course to starboard and give 1 blast, for the red and
green lights right ahead; and also for the red and green 2 points on my
starboard bow. The vessels showing the red lights broad on the bow are
heading more or less in the same direction and we are closing in slowly.
Before risk of collision is imminent I could give 1 blast, alter course to
starboard and go under their stern; or if I were passing very close I
could give 2 blasts, alter course to port and pass ahead of them, resuming
my course when I was finally passed and clear.
400
NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
NOTES RELATING TO THE ARTICLES.
Extracts from Merchant Shipping Act.
If any damage to person or property arises from the non-observance
by any ship of any of the Collision Regulations, the damage shall be
deemed to have been occasioned by the wilful default of the person in
charge of, the deck of the ship at the time, unless it is shown, to the
satisfaction of the Court, that the circumstances of the case made a
departure from the Regulation necessary.
Where in a case of collision it is proved to the Court before whom
the case is tried, that any of the Collision Regulations have been infringed,
the ship by which the regulation has been infringed shall be deemed to
be in fault, unless it is shown to the satisfaction of the Court that the
circumstances of the case made departure from the Regulation necessary.
Duty of Master in case of Collision.
In every case of collision between two vessels it shall be the duty of
the master or person in charge of each vessel, if, and so far as he can do
so without danger to his own vessel, crew, and passengers (if any),
(a) To render the other vessel, her master, crew, and passengers (if
, any) such assistance as may be practicable and may be necessary
to,save them from any danger caused by the collision, and to
stay by the other vessel until he has ascertained that she has no
need of further assistance; and also
(b) To give to the master or person in charge of the other vessel the
name of his* own vessel and of the port to which she belongs,
and also the names of the ports from which she comes and to
which she is bound.
If the master or person in charge of a vessel fails to comply with
this section, and no reasonable cause for such failure is shown, the col¬
lision shall, in the absence of proof to the contrary, be deemed to have
been caused by his wrongful act, neglect, or default; and if he is a
certificated officer an enquiry into his conduct may be held, and his
certificate cancelled or suspended.
In every case of collision, in which it is practicable to do so, the
master of every ship shall, immediately after the occurrence, cause a
statement thereof, and of the circumstances under which the same
occurred, to be entered in the official log book, and the entry shall be
signed by the master and also by the mate or one of the crew.
NOTES RELATING TO THE ARTICLES
237
If the master fails tp comply with this section he shall, for each
offence, be liable to a fine not exceeding £20.
Report of Accidents to Steamships
When a steamship has sustained or caused any accident occasioning
loss of life or any serious injury to any person, or has received any
material damage affecting her seaworthiness or her efficiency, either in
her hull or machinery, the owner or master shall, within 24 hours
after the happening of the accident or damage, or as soon thereafter as
possible, transmit to the Board of Trade by letter, signed by the owner
or master, a report of the accident or damage and of the probable
occasion thereof, stating the name of the ship, official number, port of
registry, and the place where she is. Penalty for non-compliance, a fine
not exceeding £50.
Eenalty for not exhibiting lights, a fine not exceeding £100.
CHAPTER XI.
NOTICES TO MARINERS.
These Notices are issued by the Admiralty for the information of
mariners in foreign-going vessels.
(a) Daily Notices of an .urgent nature or of major importance.
(b) Weekly Notices containing information which has become avail¬
able during the previous week for the correction of Admiralty
Charts and Sailing Directions.
(c) A Quarterly Edition gives in collated form the information
published in the weekly editions during the previous quarter.
Notices for home-trade and fishing vessels are also issued daily and
weekly.
4. On 1st January of each year the Board of Trade publishes and
distributes, for the use of foreign-going, home-trade, and fishing vessels,
a book containing general information for the guidance of Mariners,
e.j., notices regarding distress signals, life-saving, various special
signals, etc. Copies of the daily, weekly, and quarterly editions may
be obtained at any Mercantile Marine Office.
These Notices are applicable to the navigation of British waters and
some of the more permanent are, in effect, supplementary to the Inter¬
national Regulations for Preventing Collisions at Sea. We give here a
synopsis of the more important Regulations issued within recent years
up to 1936.
Closing of Ports.— When a port is closed by order of the Admiralty
3 red balls vertical are displayed from a prominent position by day, and
at night 3 red lights vertical. When those signals are shown by an
Examination vessel they are additional to her usual navigation lights.
Vessels entering the harbour proceed according to instructions;
if no instructions are given they must go to the Examination Anchorage
marked on the chart or keep out to sea.
Three white lights vertical are shown when the port is open. Vessels
are requested to have ready at hand 2 all-round red lanterns and 2
all-round white lanterns to be displayed as directed.
The examination vessels on duty fly a special flag, white and red
horizontal surrounded by a blue border.
Mine Sweeping Operations.— Mine-sweepers show a black ball at
the foremast-head and a black ball at the yardarm pn the side on which
238 ' .
SPECIAL NAVAL NOTICES
239
it is dangerous to pass. When black balls are shown at each yardarm
it is dangerous to pass on either side within a distance of at least 900
yards.
Green lights are shown at night in place of the black balls by day.
Single Vessels Approaching Squadrons.—A vessel approaching a
squadron of warships should avoid going amongst them. If unable
to keep out of their way the ordinary Regulations for preventing
collision apply.
Warning Signals to Denote Presence of Submarines.—The vessel
escorting the submarines displays a square red flag. She should be
given a wide berth and, if it is necessary to pass close to the escort,
vessels should proceed at slow speed and keep a sharp lookout for
periscopes.
Aircraft at Anchor show the same lights as surface craft and also
wing tip white lights when the span exceeds 150 feet.
AIRCRAFT.
Information with regard to Distress Signals by Day and Night.—
Mariners and others are notified that when any aircraft is in distress
and requires assistance, the following shall be the signals displayed by
her, either together or separately:—
I. The International Signal “S OS” by means of Visual or
Wireless Telegraphy or in the case of Radio Telephony the
spoken word “Mayday.”
II. The International Code Signal of Distress indicated by N.C.
11 f. The Distant Signal consisting of a square flag having above or
below it a ball or anything resembling a ball.
IV. A continuous sounding with any sound apparatus.
V. A signal consisting of a succession of white pyxotechnical lights,
fired at short intervals.
VI. A white flare from which at intervals of about 3 seconds a white
light is ejected into the air.
In the event of a distress call being received from" an aircraft in
distress over the English Channel, the position of the aircraft will- be
fixed by directional wireless from the appropriate B.F. stations and a
warning will theif be broadcast to shipping by'North Foreland wireless
station giving the necessary particulars.—December, 1927.
240 NICHOLLS’S SEAMANSHIP AND NACJTICAL KNOWLEDGE
SALVAGE OF TORPEDOES.
Instructions for the Recovery and Safe Handling of Torpedoes
lost from H.M. Ships.
1. A torpedo is a cigar-shaped object, varying from 15 to 22 feet
long, and from 14 to 21 inches in diameter. It has a more or less
pointed nose and tapering fail. At the after end of the tail are fins,
rudders, and two screw propellers, one immediately abaft the other. It
is generally made entirely of steel. The weight of torpedoes varies from
under half a ton to a ton and a quarter.
2. A Torpedo used in Peace Exercises never contains any Explosive
Material. A calcium light is used in the nose to assist in recovery; it is
quite harmless and may be left to bum out.
3. A person who does not understand the mechanism of a torpedo
should be careful to avoid touching any small levers which project from
a slit in the upper part of the torpedo a little abaft the middle of the
body of the torpedo. It is possible under certain conditions, that the
screw propellers of a derelict torpedo may be caused to revolve rapidly
if these levers are moved. Fingers, hands and body should be kept
clear of the propellers at all times in case they should be accidentally
started, when a nasty cut may result.
4. A torpedo may be found floating, sometimes lying flat along the
surface of the water, and sometimes with its tail submerged and its nose
only showing above the water.
5. It should be taken in tow by means of a wire or stout rope (at
least 3 ins.) with a running eye (or noose) in the end.
6. If the tail of the torpedo can be reached, the running eye should
be passed over the screw propellers and fins and bowsed taut around the
small part of the tail.
7. If the tail is submerged, the running eye should be dropped over
the nose and allowed to fall down until it grips the small part of the tail
in the same way.
8. The torpedo should then he towed tail first.
9. Should it be desired to hoist a torpedo inboard it should be slung *
with a good wire strop around the centre of the torpedo; the balancing
point is about in line with those projections on each side which are
rather less than half way from nose to tail. Before hoisting, lines
should be made fast to-the tail and nose and these lines should be
attended so as to keep the torpedo level while hoisting, and prevent it
LIGHTVESSELS
241
slipping through the strop. When the torpedo is inboard, it should be
lashed down to the deck, or on wooden chocks to keep it off the deck,
and the screw propellers should be well lashed together to prevent any
chance of their starting to revolve.
10. A torpedo when recovered should be handed over to the most
convement Coastguard or Naval Authority, with a statement of where
it was found, and any details of importance.
11. A reward of at least £f> is offered for a lost torpedo after it has
been missing for a day.
12. In case of damage to gear or loss of any kind incurred in the
recovery of a torpedo, a written statement should be handed over with
the torpedo, and any reasonable increase in the reward will then be
considered by the Admiralty.
SIGNALS FROM H.M. SHIPS,
When a man-of-war desires to commumcate with a merchant
vessel, she will hoist the Code Pendant m a conspicuous position and
keep it flying during the whole time the signal is being made,
PILOTS.
Caution —In view of the danger and difficulty often attending the
shipping and discharging of pilots in exposed positions, the attention of
masters is directed to the necessity of observing every precaution in
manoeuvring their ships when a pilot is either boarding or leaving,
especially in cases where a vessel is in ballast and strong winds are
prevailing. The master or officer in charge of the bridge should take
care to satisfy himself, on dropping the pilot, that the latter is well
clear of the ship and particularly of the counter before the propeller is
moved.
LIGHTVESSELS IN THE UNITED KINGDOM.
Regulations.—The following Regulations have been established
respecting the several lightvessels on the coasts of the United Kingdom,
viz.:—
A white light is exhibited from the forestay of each lightvessel, at
a height of 6 feet above the rail, for the purpose of showing in
which direction the vessel is riding, when at her station.
Light Vessels under the jurisdiction of the Corporation of Trinity
House when not in their correct position as a safe guide to shipping
will continue the present practice of not showing their characteristic
light or sounding their fog signal, and on and after the 1st July , 1931,
will exhibit the following special signals, viz.:—
242
NTCHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
By Day.—The characteristic topmark will be struck if practicable.
Two large black globes or shapes will be exhibited one forward and one
aft. The International Code Signal W P.C.” will be flown.
By Night —Two red lights will be exhibited one forward and one aft.
Two flares, one red and the other white, will be shown simultaneously
at least every quarter of an hour or if the use of flares be impracticable a
red light and a white hght will be displayed simultaneously.
Watch buoys are can buoys painted red, with “Watch” preceded
by lightvessel’s name in white letters. They are moored near
the vessel to mark position.
If from any cause the lightvessel be unable to exhibit her usual
lights whilst at her station, the riding light only will be shown.
The mouths of fog horns, which are not fitted to distribute the sound
equally all round, are pointed to windward.
At lightvessels where a hand horn is used, the intervals will be
shortened as vessels approach, and should a vessel come danger¬
ously close the sound will be continuous until she has passed.
When, from any of the lightvessels or from Trinity House Light¬
house a vessel is seen standing into danger, the two signal flags
J D of the International Code, “You are standing into danger,”
will be hoisted and kept flying until answered. In addition to
the above flag signal the lightvessel will fire a gun or socket
signal, and repeat it at short intervals until observed by the
vessel.
It should be remembered that lightvessels are liable to be with¬
drawn for repairs, without notice, and in some cases not replaced
by relief vessels.
COLLISIONS WITH LIGHTVESSELS.
Caution .—In consequence of lightvessels being from time to time
run into and seriously damaged by vessels navigating in their vicinity,
the Corporation of Trinity House deem it desirable to warn mariners
that when passing a lightvessel, and particularly when attempting to
cross her bows, they should make due allowance for the set of the tide
and take every other precaution desirable in the circumstances in order
to avoid striking the lightvessel. Attention is specially directed to the
666th section of the Merchant Shipping Act, 1894, which provides that
anybody wilfully or negligently running foul of any lightvessel or buoy
shall, in addition to the expense of making good any damage so
occasioned, incur a penalty of £50.
NOTICES TO MARINERS
243
VESSELS NAVIGATED STERN FOREMOST.
Such vessels display two balls, each 2 feet in diameter, carried at
the ends of a horizontal jackyard on the mast or, if the vessel has more
than one mast, on the main or after-mast. The jackyard will be placed
in a thwartship direction, at least 6 feet higher than the funnel top, and
will project at least 4 feet on either side of the mast, so that the distance
between the centres of the two balls will be at least 8 feet.
Bye-laws giving effect to this arrangement have been made for the
ports of Dover, Ramsgate, Holyhead, Lame and Belfast.—July 23,
1930.
SUBMARINE CABLES.
Should a submarine cable be lifted to the surface by a vessel heaving
up anchor she should pass the end of a 5-inch manila rope (do not
use wire) under the cable, make the end fast inboard, haul the rope
tight and hang the cable on the bight of the rope, then lower the anchor
clear of the cable which can then be slipped. The fouling of a cable
together with the position as accurately as possible should be reported
the nearest cable station.
Skippers of trawlers are urged to exercise caTe when trawling near
telegraph cables, and if a cable is fouled great caution should be exercised
in attempting to clear it. It is advisable to sacrifice the gear rather
than to exert force in freeing it. Compensation for loss of gear is made
on a sworn declaration being made and upheld.
SEINE NET FISHING BOATS SHOW.
By Day.—One black ball or basket in the forepart of the vessel and a
black cone or triangle, apex upwards, at the mizzen yardarm. Pass
her on the clear yardarm side.
By Night.—Three white lights in a triangle, apex upwards, from the
yardarm on the Side from which the gear is leading. She exhibits her side¬
lights when running out the gear, but no side-lights when hauling it in.
Sound Signal.—Seme net vessels give 4 blasts, 3 long and 1 short,
on the whistle (— —- ■■■ *) when approached by other vessels. In
fog, seine net vessels give the same signal as other fishing vessels.
These special lights and signals are given to warn vessels off their nets
as the warps and gear may be as much as a square mile in extent.
When flares are displayed by a fleet of fishing vessels on being
approached by another vessel they are warning her off their nets. It
is necessary to give them a wide berth as a train of nets may extend
over an area of one square mile.
244
NICHOLLs'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
SYSTEM OF BUOYAGE (1947)
Adopted by the leading Pilotage Authorities
The mariner when approaching the coast must determine his position
on the chart and note the direction of the main stream op flood
TIDE.
The teim Starboard Hand shall denote that side which would he on
the right hand of the manner either going with the mam stream of
flood or entering a harbour, nvei, or estuary from seaward, the term
Port Hand shall denote the left hand of the manner under the same
circumstances
Buoys are named Conical Can or Spherical according to their shape
above water. Conical buoys are kept on the starboard hand, Can buovs
on the port hand when going m the direction of the flood stream.
Spherical buoys mark the ends of Middle Grounds. See Fig. 4
Buoys having a tall central structure on a broad base aie
called Pillar buoys and, like other special buoys such as Bell buovs,
Gas buoys, Automatic signalling buoys, etc., shall be placed to mark
special positions either on the coast or m approaches to harbours.
Wreck buoys m the open sea, or m the approaches to a harbour or
estuary, shall be coloured green, with the word “Wreck” painted m
white letters on them. Submarine telegraph cable buoys are painted
black with the word “Telegraph” in white letters on them.
Starboard Hand Marks. —Conical buoys. Black (B) or Black and
White Chequers (B.W. Cheq.). Topmarks (if any)—Black Cone (point
upwards) or, for purposes of differentiation except at entrance to a
channel, a Black Diamond. Light (if any)—White showing 1 or 3
or 5 flashes
Port Hand Marks. —Can buoys. Bed (R) or Bed and White Chequers
(B.W. Cheq.) Topmarks (if any)—Bed Can or, for purposes of
differentiation, a Bed “T” except at entrance to a channel. Light
(if any)—White showing 2 or 4 or 6 flashes, or Bed flashes up to 4.
Middle Ground Marks. —Spherical buoys Red and White Horizontal
Bands (R.W.H.B ) where mam channel is to the right or the channels
NIC’HOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE 24
ane of equal importance Black and White Horizontal Bands (B.W.H.B
where the main channel is to the left. Topmarks (if any)— (a) Mai*]
channel to eight. Outer End, Red Can; Inner End, Red iC T”. (6
Mam channel to left: Outer End, Black Cone: Inner End, Blaol
Diamond. ( c ) Channels of equal importance* Outer End, Red Sphere
Inner End, Red St Georges’ Cross Lights (if any)—As far as possible
light * will be distinctive, but no colours will be used other than white
or ted, and neither colour will be such as to lead to uncertainty as tc
the side on which the mark shall be passed.
Mid Channel Marks. —Shape to be distinctive and different from the
principal characteristic shapes (conical, can or spherical). Coloured
Black and White Vertical Stripes (B W.Y S.) or Red and White Vertical
Stupes (R W V S ).
Topmarks (if any)—Distinctive shape other than cone, can or
sphere Light (if any)—Different from neighbouring lights or marks
at bide of channel
Isolated Danger Marks. —Spherical, with' wide Black and Red
Horizontal Bands separated bv a nairow White Band Topmarks (if
any)—Sphere jiamted Black or Red or half Black and half Red horizon¬
tally. Light (if any)—White or Red with flashing character
Landfall Marks. —Shape m accordance with channel marking
painted Black and White or Red and White Vertical Stripes. Light
(if any)—Flashing character.
The Conical, Can and Spherical shaped buoys are retained in the
new bystem, but the distinctive colourings and topmarks are changed.
Instead of starboard hand buoys (Conical) being painted m one
colour only they are now to be painted all black, or black and white
chequers. The Port Hand buoys (Can), formerly single or parti-coloured,
are now to be all red, or red and white chequers. The Spherical buoys at
the ends of a Middle Ground, instead of the distinctive white and black
horizontal bands as formerly, are now to be painted red and white, or
black and white horizontal bands.
Distinctive Topmarks, when fitted, are to be shaped as a cone,
diamond, can, sphere, St. George’s Cross or a U T 55 . A black cone or a
black diamond on starboard hand buoys. A Red Can or a Red e ‘T” on
Port Hand buoys. The R.W.H.B. Middle Ground buoys indicating
that the main channel is to the right may have a Red Can on the outer
246
NICHOLL&’s SEAMANSHIP AND NAUTICAL KNOWLEDGE
end and a Bed “T” on the inner end But should the channels to right
and left be of equal importance then the Topmark will be a Bed sphere
on the outer end and a Bed St George's Cross on the inner end
Special marks and colourings to distinguish mid channels, isolated
dangers and landfall marks are as described previously.
Buoys and Beacons
Wrecks have occurred through undue reliance on buoys and floating
beacons always being maintained m their exact position
They should be regarded^ simply as aids to navigation and not as
infallible marks, especially when placed m exposed positions.
The lights shown by gas buoys cannot be implicitly relied on as,
if occulting, the apparatus may get out of order, or the light may be
altogether extinguished.
v WRECK MARKING SIGNALS.
To be passed on the mariner’s starboard hand when going in the
direction of the flood stream.
By Day.—Three green balls (3) vertical at the yardarm, 6 feet
apart, the lowest to be at least 9 feet above the hull.
By Night .—Three green lights (3) m place of the balls.
In Fog.—Three strokes (3) on a deep toned bell every 30 seconds.
Wreck Buoy.—Green conical giving 3 green flashes every 10 or 15
seconds if lighted. The chart abbreviation would be, Con. Gn. FI (3)
ev. 15 sec.
To be passed on the manner’s port hand.
By Day—Two green balls (2) vertical at the yardarm, 6 feet apart,
the lower one to be at least 15 feet above the hull.
By Night .—Two green lights (2) in place of the balls.
In Fog—Two strokes (2) on a deep toned bell every 30 seconds.
Wreck Buoy.—A green can buoy giving two green flashes everv 10
seconds if lighted. Chart abbreviation, Can Gn. FI. (2) ev. 10 sec.
To be passed on either side.
By Day.—Two green balls (2) vertical at each yardarm, 6 feet apart,
the horizontal distance between them from 15 to 25 feet.
By Night.—Four green lights (4) in place of the 4 balls.
FOG SIGNALLING APPABATU8
247
In Fog.—Four strokes (4) on a deep toned bell.
Wreek Buoy.—Green spherical giving one green flash (1) every 5
or 6 seconds if lighted. Chart abbreviation, Sph. Gn. FI. (1) ev. 5 sec.
Wreck marking vessels should be given a wide berth when passing
them?
INFORMATION RE FOG SIGNALS.
The following information in regard to fog signals is promulgated
for the guidance of mariners:
1. Fog signals are heard at greatly varying distances.
2. Under certain conditions of atmosphere, when an air fog signal
is a combination of high and low tones one of the notes may
be inaudible.
3. There are occasionally areas around a fog signal in which it is
wholly inaudible.
4. A fog may exist a short distance from a station and not be
observable from it, so that the signal may not be sounded.
5. Some fog signals cannot be started at a moment’s notice after
signs of fog have been observed.
Mariners are therefore warned that fog signals cannot be implicitly
relied upon and that the practice of sounding should never he neglected.
Particular attention should be given to placing “Look-out men” in
positions in which the noises in the ship are least likely to interfere
with the hearing of the sound of an air fog signal; as experience shows
that, though such a signal may not be heard from the deck or bridge
when the engines are moving, it may be heard when the ship is stopped,
or from a quiet position. It may sometimes be heard from aloft though
not on deck.
There are three means adopted for signalling in fog:—
(a) By air sound signals comprising (1) Diaphone, (2) Siren,
(3) Heed, (4) Nautophone, (5) Gun, (6) Explosive, (7) Bell
or Gong, and (8) Whistle;
( h ) By submarine sound signals produced either by (9) an
Oscillator or (10) Bell; and
(c) By Wireless Telegraphy.
I. Air Fog Signals.
The Diaphone (1), Siren (2), and Reed (3) are all three compressed
air instruments fitted with horns for distributing the sound.
The Diaphone emits a powerful low-tone note terminating with a
248 NICHOLAS SEAMANSHIP AND NAUTICAL KNOWLEDGE
sharp descending note teimed the “grunt,” the Siren a medium powered
note, either high or low or a combination of the two, and the Reed a
high note of less power. Reeds may be hand-operated, in which case
the signals from them are of small power.
The Nautophone (4) is an electrically-operated instrument also
fitted with a horn, and emits a high note signal similar in power and tone
to that of the Reed
Gun (5) and Explosive (6) signals are produced by the firing of
explosive charges, the former being discharged from a gun, and the
latter being exploded m mid air.
Bells (7) may be operated either mechanically or by wave action,
in which latter case the sound is irregular. The notes may be high,
medium or low according to the weight of the bell. Gongs are also
sometimes employed.
A Whistle (8) is a signal of low power and tone sometimes fitted on
a floating body, when this is the case the sound is produced by air
drawn in and compressed during the upward and downward movement
of the body due to wave action, and is consequently irregular.
II. Submarine Sound Signals.
The Oscillator (9) is an electrically-operated instrument sounding
a high note signal.
Bells (10) may be operated either mechanically or by wave motion,
in which latter case the sound is irregular.
The effective range of submarine sound signals far exceeds that of
air sound signals having been known to exceed 50 miles in the case of
an oscillator and 15 miles in that of a bell. Their bearings can be
determined with sufficient accuracy for safe navigation in a fog if a
vessel is equipped with receivers, and even should a vessel be not so
-equipped submarine signals may be heard from below the waterline
for distances which are well outside the range of air fog signals, though
their bearings cannot then be so well determined.
III. Wireless Fog Signals.
These are provided for the purpose of position finding.
There are three types employed (11) Beacon , (12) Revolving Beam ,
and (13) Rotating Beacon or Loop Stations.
The Beacon Station (11) consists of an all-round wireless trans¬
mitter sending out a code signal in every direction, the bearing of
which is obtained by means of a wireless direction finder or wireless
compass fitted on board ship. When the wireless signal is combined
FIG. A
FIG. 3
life-saving service signals
249
and synchronised with a submarine sound signal, distance, as well as
bearing can be determined.
The Revolving Beam Station (12) consists of the emission on short
wave-lengths of wireless signals projected in a narrow beam, a different
Morse letter signal being transmitted for each point and half-point of
the compass The navigator listens by means of a special type of
wireless receiver (independent of the ordinary W/T installation) and
hears a series of five or more Morse letters, transmitted at a uniform
speed, as the revolving beam intersects the ship’s course. The middle
letter of the series indicates the exact bearing of the ship (derived from
a special chart giving the lettered sectors) in relation to her course. By
repeating the observations at short intervals and co-ordinating the
results with the ship’s course and speed, the exact position of the ship
can be determined.
The Rotating Beacon or Loop Station (13) consists of a medium
wave wireless beam transmitter rotating at a uniform speed. A con¬
tinuous signal is transmitted with special code signals as the beam
passes certain points of the compass These signals are received on a
standard wireless receiver, and as the beam rotates the signal strength
rises and falls being at a minimum as the beam passes the ship. Ajs the
speed of the rotation of the beam is known, the bearing of the station
can be calculated by measuring the time interval between the beam
passing a known point of the compass (indicated by the transmission
of the code signal referred to above) and passing the ship (indicated by
the minimum strength of signal)
II. VISUAL AND SOUND SIGNALS.
Signals used in connection with the Life-Saving Services on the Coasts
of Great Britain and Northern Ireland.
Signal .
(a) Signals to Vessels in Distress
Rocket throwing white stars, or
white flare.
One explosive sound signal showing
bright white star on bursting.
Two explosive sound signals, show-
hag bright green stars on bursting.
Signification .
Distress signal or plight
observed — Assistance
summoned.
Distress signal or plight
observed — Life-Saving
Apparatus called out.
Distress signal or plight
observed — Lifeboat
called out.
250
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Signal
Three explosive sound signals, the
first showing white star on bursting and
the second and third gieen stars.
Signification.
Distress signal or plight
observed — Life-Saving
Apparatus and Lifeboat
called out.
Note 1 . —By day a Red Flag (Rectangular or Swallow-tailed) will be
flown when the Life-Saving Apparatus is called out, and a Red Flag
(Triangular) when the Lifeboat is called out.
Note 2.—Certain pyrotechnic signals consisting of three or more
rockets throwing white stars on bursting or a green flare turning to
white are used on occasions for communication between the shore
and a lifeboat. A hfeboat when out on service may make any of the
following signals: A white flare to indicate that she is approaching a
wreck. Red flares to indicate to the shore that more aid is required and
a green or green turning to white flare to notify to those ashore that she
is returning.
(b) Landiiig Signals .
Signal. Signification,.
By day .—Flag held upright over
bead. You may attempt to land
By night.—White flare held steady here,
or stuck in ground.
By day .—Flag waved from side to
side.
By night—White flare waved from
side to side.
Landing is extremely dan¬
gerous. You are advised
to lay off until lifeboat
arrives.
By day .—Flag waved to right or
left and then pointed in direction.
By night.—White flare held steady
and carried along shore to right or left.
The best landing will be
found in the direction in
which flag is pointed or
light carried.
By day. —Two flags held upright
overhead, the men holding them being
about 50 yards apart in line of
approach.
By night —Two white flares held or
stuck in ground or two bonfires placed as
abova
You should attempt to
* land and by this line of
approach.
FOG SIGNALLING APPARATUS
251
(a) Standing into Danger Signals.
Signal . Signification .
The International Code Signal JD |
The letter U (• - «.} flashed by lamp r You are standing into
or made by foghorn, or whistle, etc. J danger.
Note .—If it should prove necessary, the attention of the vessel is
called to these signals by a white flare, a rocket showing white stars on
bursting, or an explosive sound signal.— June 1 , 1930.
The actual launching of the lifeboat js notified by a green Verey’s
light.
BOARD OF TRADE INSTRUCTIONS.
For the Guidance of Masters and Seamen when using the Rocket
Apparatus for Saving Life
In the event of your vessel stranding on the coasts of the United
Kingdom, and the lives of the crew being placed m danger, k assistance
will, if possible, be rendered from the shore m the following manner,
namely:—
1. A rocket with a thin line attached will be fired across your vesseL
Get hold of this line as soon as you can, and when you have
secured it, let one of the crew be separated from the rest, and,
if in the day time, wave his hat, or his hand, or a flag or handker¬
chief: or, if at night, let a rocket, a blue light, or a gun be fired,
or, let a light be waved as a signal to those on shore.
2. When you see one of the men on shore separated from the rest
wave a red flag, or, if at night, wave a red light; you are to haul
upon the rocket line until you get a tailed block with an endless
fall rove through it (Figure (i)).
3. Make the tail of the block fast to a mast well above ihe.dech, or
if vour masts are gone, then to the best place that can be found—
252 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
bearing in mind that the lines should be kept clear from chafing
the wreck, and that space is left above foi the hawser (see par.
5). When the tail block is made fast, and the rocket line un¬
bent from the whip, let one of the crew, separated from the
rest, make the signal required by Article 1 above
4. As soon as the signal is seen on shore, a hawser will be bent to
the whip line, and will be hauled off to the ship By those on
shore.
5. When the hawser is got on board, the crew should at once make
it fast to the same part of the ship as the tailed block is made
fast to, only about 2 feet higher (Fig (ii)) taking care that there are
no turns of the ivhip line round the hawser , the whip should then
be unbent from the hawser.
6. When the hawser has been made fast on board, the signal directed
to be made in Article 1 above is to be repeated.
7. The men on shore will then set the hawser taut, and by means of
the whip line will haul off to the ship a sling lifebuoy, into which
the person to be hauled ashore is to get (Fig. (in)). When he is in
and secure, one of the crew must be separated from the rest,
and again signal to the shore as directed m Article l above.
The people on shore will then haul the person m the sling to
the shore, and when he has landed will haul back the empty
sling to the ship for others This operation will be repeated
until all persons are landed.
8. It may sometimes happen that the state of the weather and the
condition of the ship will not admit of a hawser being set up;
in such cases, a sling lifebuoy will be hauled off by the whip,
which will be used without the hawser.
9. This method is only adopted when shipwrecked persons have to
be landed on to a pier or high ground, and is never to be used
on flat shores.
Masters and crews of stranded vessels should bear in mind that
success in landing them in a great measure depends upon their coolness,
and attention to the rules here laid down; and that by attending to
them many lives are annually saved by the rocket apparatus on the
coasts of the United Kingdom.
The System of Signalling must he strictly adhered to; and all women,
children, passengers, and helpless persons should be landed before the
crew of the ship.
LINE-THROWING APPARATUS
253
DISTRESS SIGNALS*
Two of the statutory signals, viz., £f a continuous sounding with
any fog signal apparatus,” and “flames from the ship,” are liable to be
contused with a vessel making similar signals merely to attract attention
only, or, providing working flares on fishing boats.
It is recommended that Morse signals of distress made on a fog
horn or with a lamp should be a continuous repetition of S 0 S (Morse)
and the same for a visual distress signal on a lamp.
Instead of flames from the vessel it is recommended that red flares
should be used and. particularly, a firework signal showing a brilliant
red flare and throwing five or more red stars to a height of 80 feet.
LIFE-SAVING APPLIANCES RULES—LINE-THROWING
APPLIANCES ON SHIPS*
Every ship of 500 tons gross and upwards, when proceeding on a
voyage or excursion from a port in the United Kingdom, must carry
line-throwing appliances which shall be at least as effective as the
following apparatus, viz..—
Four 2-lb. line throwing rockets with suitable sticks capable of
throwing a lme 5/16ths inch in circumference a distance of 120 yards
in calm weather. Two such lines, each not less than 240 yards in
length, having a breaking strain of not less than 150 lbs.
Rockets —Should be specially made for line throwing ( Le without
stats or detonating composition) by approved manufacturers. They
should have a watertight outer case and should be marked with the
date of manufacture. The means of ignition should be either by
(i) slow-burning fuse at the base ignited by portfire or by (ii) a frictional
striker applied to slow burning composition at the base or side of
rocket. In either case the arrangement should allow for a delay of
not less than three seconds before the rocket commences its flight.
In the case of a frictional ignition, its striker should be carried, ready
for use, in a small sheath on the rocket. Rockets should be replaced
at least every five years.
Sticks .—To be not less than 5 feet in length and to be attached
to the rocket when required for use by a spring clip engaging in a slot.
Container .—Rockets, lines and portfires (if used), with a copy of
directions for use of the appliance, should be stowed together in a
watertight case, i.e., in a case which is sufficiently weathertight and
watertight to keep the rockets available for use at any time.
254 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
The illustration shows the Schermuly Pistol Rocket Apparatus.
The line is m the box, flaked in a special manner to ensure free running
The line is attached to the rocket, the rocket fits on to the barrel of
the pistol and is ejected from the muzzle by means of a cartridge, and
immediately thereafter the rocket begins to function as a rocket
proper carrying the line with it.
Fig 2.—The Schermuly Pistol Rocket Apparatus
Attention has been called by the Board of Trade to the danger of
attempting to establish communication, by means of a rocket line¬
throwing apparatus, with an oil tanker, should that vessel be carrying
petrol spirit, or other highly inflammable liquid and be leaking; petrol
spirit rises to the surface of water. In such cases the assisting vessel
should lie to windward of the tanker and the communication should be
established from the ship ’requiring assistance. Before firing a rocket
to such a vessel it should be ascertained whether it is safe to do so.
BELLS, WHISTLES AND FOG HOBN8
255
BELLS, WHISTLES AND FOG HORNS.
Bells.—All steam and sailing vessels must be provided with an
efficient bell. The bell should be hung clear of all obstructions, and
not less than 12 inches in diameter at the mouth, except m the case
of small vessels under 150 feet in length working in rivers, estuaries
or inland lakes, when a bell of not less than 8 inches in diameter may
be accepted.
Steam Whistles.—All steam vessels and all vessel? propelled by
machinery on the high seas and in all waters connected therewith
navigable by sea-going vessels are required to be provided with an
efficient whistle or siren, sounded by steam or some substitute for
steam, and so placed that the sound may not be intercepted by any
obstruction. The whistle should be at least 8 feet above the deck
forward of the foremost funnel and well clear of, and above, deckhouses,
ventilators, etc.
Ordinary “organ whistles’’ should be not less than 30 inches high
and 5 inches in diameter, and “harmony whistles,” “bell chime” steam
whistles and whistles or sirens of other approved types should be of
proportionate dimensions
A whistle or siren is not to be regarded as efficient unless it is audible
for at least 2 miles m a still condition of the atmosphere.
Whistle pipes should be so arranged that a full supply of dry steam
will at all times be immediately available when the vessel is under
way, and to ensure this it should not be possible for water to lodge
in the pipes.
The pipes should not, as a rule, except in small vessels under 150
feet in length, be less than 2 inches outside diameter. All pipes should
be lagged.
The whistles of all new vessels should be tried, and unless a full
clear sounding blast is immediately produced they should not be passed.
Whistles on Motor Ships.—Vessels fitted with electric or oil motor
engines, whether auxiliary or otherwise, for propelling purposes are
steam vessels within the meaning of the Collision Regulations, and
should therefore be provided with an efficient whistle or siren sounded
by steam, or some substitute for steam. Compressed air may be used.
Small motor vessels, coasting or making short sea voyages, must
carry an efficient mechanical or electric horn of a type capable of
producing the sound signals required by the Collision Regulations,
and, if fixed, must be so placed that the sound from it will not be unduly
obstructed, and will carry a distance of at least 2 miles.
256 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
In t he case of motor boats plying on rivers or inland lakes, a horn
or an electric bell audible for at least half a mile may be allowed instead
of a whistle, if the owners so desire.
Fog Horns.—Article 15 of the Collision Regulations requires that
the necessary signals for vessels under way shall be given (1) by steam
vessels on the whistle or siren; (2) by sailing vessels and vessels towed,
on the fog horn. Whistles required for steam vessels are described
above, but all steam vessels must, m addition, be provided with an
efficient fog horn to be sounded by mechanical means.
Fog horns of the “rotary” and “crank bellows” type are the most
efficient at present in use. “Plunger” type fog horns are rarely found
to be efficient, and should only be accepted if entirety satisfactory.
Horns blown by mouth cannot be accepted as efficient on vessels
plying on the high seas, or in waters connected therewith navigable
by sea-going vessels.
SCREENING OF LIGHTS.
Side-Lights: Screening Abaft the Beam.—The wick or wicks of a
side-light must be placed at an angle of 112^° with the fore-and-aft
line of the ship; in other words they must be parallel to the direction
two points abaft the beam. The burner must be so placed that a
line drawn in this direction from the after edge of the wick in the case
of a single burner, and of the forward wick in the case of a duplex
burner, shall cut the edge of the housing of the lens.
Side-Lights: Screening Forward.—The screens of side-lights, the
length of which should never be less than 36 inches from the dame
to the chock or its equivalent, must always be placed parallel to the line
of the keel. The chocking must be so arranged to show a “thwart-
ship value” of at least 1 inch of wick in a forward direction; that is to
say, a person looking past the edge of the chock in a line parallel to
the keel must be able to see at least 1 inch of wick.
Masthead Lights: Screening.—In a masthead light the wick or
wicks must be at right angles to the line of the keel, and their setting'
must be such that lines drawn from the centre of the after edge of the
wick in the case of a single burner, and of the forward wick in the case
of a duplex burner, in directions two points abaft the beam on each
side, shall cut the edges of the housing of the lens.
Stem Lights: Screening.—If a fixed stern light is fitted, the wick,
NAVIGATION LIGHTS
257
which must in this case be a single one, should be set as in the masthead
light and so screened that a line drawn from the centre of the wick
in a direction two points abaft the beam shall cut the edge of the housing
of the glass front of the lantern.
Electric Lights.
18. General.—Electric lanterns are not required to be of a type
approved by a certificate of approval and such certificates will not, in
general, be issued. Subject to this, and except where otherwise stated
or where the context implies otherwise, the instructions relating to
lanterns in which oil is burned apply equally to those in which electric
light is used. Separate lanterns must always be provided for electric
and oil lamps, and oil lanterns must in every case be carried. Lanterns
in which electric light is used should, as far as possible, be air-tight and
the lanterns should be made to open from the top in order to afford
facilities for cleaning and repair, and the checking of measurements.
258 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
An electric lantern should, as a rule, be fitted with a plain, colourless,
glass front, cylindrical in form, which should be at least 5/16 of an inch
in thickness, in order to obviate the probability of breakage. The
glass should be highly polished and free from air bubbles or other
visible defects. A dioptric lens may be fitted instead, if the owner so
desires, but where this course is followed the lens must be of an approved
type, and the lantern must comply strictly with para. 24.
19. Voltage.—The voltage of the electric supply on board should be
not less than 110 or greater than 220 volts The supply of electric
current for navigation lights should be kept at its full voltage throughout
the voyage, and opportunity should be taken to point this out to
masters of ships, as under-running of the voltage may result in serious
loss of candle power.
20. Candle Power.—Either 60 watt or, preferably, 100 watt lamps,
which will give candle powers of, approximately, 50 or 80 candles
respectively, should be used.
21. Form of Lamps.—Metal filament lamps should be used in all
cases, as carbon filament lamps of the candle power required involve
risk of serious over-heating.
Lamps should be of the normal type, having the usual cylindrical
(“squirrel cage”) form of filament.
The diameter of the cage formed by the filament should be not less
than 1 inch [see para 26) and not greater than If inches.
22. Double Filament Lamps.—The use of double filament lamps, one
filament of which is intended for working purposes and one for emer¬
gencies if the former fails, is not permitted, as it is impossible to obtain
an adjustment of the screening which will be correct in relation to
both filaments.
23. Gas-filled Lamps.—The Board of Trade are advised that these
lamps, as at present manufactured, 'are not suitable for use in ships’
navigation lanterns. Their use, accordingly, should not be permitted
without prior reference to the Mercantile Marine Department.
24. Position of Electric Bulb.—The upright position (pip upwards)
should be adopted in all cases.
If the lantern used with an electric lamp is fitted with a plain glass
front, the exact height of the luminous centre of the source of light, in
relation to the centre of the glass, is immaterial.
If. however, an electric lantern is fitted with a dioptric lens, the
height of the socket is to be so adjusted that the luminous centre of the
source of light coincides with the centre of the lens.
NAVIGATION LIGHTS
259
Further, in lights fitted with dioptric lenses, the luminous centre
of the filament should always be the same distance above the cap, and
to ensure that this condition is fulfilled a sufficient supply of spare
lamps of identical dimensions should be carried on board. This reserve
stock should be inspected.
25. Side-Lights: Screening Abaft the Beam,—Lamp sockets should
be so placed m the lantern cases that a line drawn in a direction two
points abaft the beam, touching the forward edge of a circle, f-mch
diameter, concentric with the socket, will cut the edge of the housing.
The centre of the lamp socket should be placed iuch abaft the
centre from which the curvature of the lens is struck.
26. Side-Lights: Screening Forward.—The chocking must be so
arranged so as to show a “thwartship value” of at least 1 mch of
filament m a forward direction.
27. Masthead Lights Screening —Lamp sockets should be so placed
m the lanterns that lines drawn in directions two points abaft the beam
on each side touching, tangentially, the forward side of a circle f-mch
diameter concentric with the lamp socket will cut the edges of the
housing of the lens. The centre of the lamp socket should be placed
t* mch abaft the centre from which the curvature of the lens is struck.
28. Fittings.—The usual type of bayonet fitting should be used.
The inside diameter of the socket should be f-mch, or J-inch larger than
the diameter of the circle to which the light is screened abaft the beam,
as described in paragraphs 25 and 27.
Special care should be taken to see that the lamps fit closely into
the sockets, so that when in position they are upright and secure.
NOTICES TO MARINERS
Questions
1. Who issues Notices to Mariners and where are they obtained?
2. What signals are shown when a port is closed and what would
you do on entering a closed port and no instructions were issued?
3. What lights are shown by an Examination vessel?
4. Give the day and night signals for a vessel sweeping for mines.
5. What precautions should be taken when approaching a squadron
of warships?
6. What flag is displayed by a submarine escort and what action
would you take on approaching her?
260 NICHOLAS SEAMANSHIP AMD NAUTICAL KNOYVLIfil>GJ£
7. What lights are shown by an aircraft at anchor^ What other
vessel shows similar lights?
8. Give the signals of distress for aircraft.
9 Describe briefly how you would go about picking up a stray
torpedo.
10. What precautions should be taken when shipping and discharging
a pilot?
11. What precaution should be taken when a foreign pilot is piloting
the ship?
12. What do you understand by the helm orders “starboard”
and “port”?
13. When passing a lightship at night how could you tell how she
was heading?
14. What signals are shown by a lightship driven from her station?
15 What is a “watch” buoy?
16. How could you distinguish any particular lightship by day if
too far ofl to read her name?
17. What light is shown by a lightship when her distinguishing
lights are out of action?
18. What signals are given by a lightship to warn ofl an approaching
vessel?
19. A nearby warship hoists the Red Ensign, what does it mean?
20. What is the penalty for negligently fouling buoys and lightships?
21. You are crossing any vessel moored in a tideway, what pre¬
caution would you take?
22. A vessel with a bow rudder is coining out of a dock stern fore¬
mast, what day signal does she exhibit?
23. Describe how you would clear a telegraph cable brought to the
surface with the anchor.
24. Give the day and night signals to be shown by a vessel as required
by Port Health Authorities in U.K.
25. Give the day and night signals for a seine net Ashing vessel.
26. What sound signals are given by a seine net Ashing vessel when
being approached by another vessel (i) in clear weather; (ii) in fog.
27. What precautions should be taken when approaching a fleet of
net drifters showing flare-up lights?
QUESTIONS
261
28. Describe and illustrate the uniform system of buoyage with
topmarks if any.
29. What degree of dependence can be placed on buoys, lightships
and, moored beacons?
30. What would you do when entering a port and sight the following
signals ?
(i) Three green lights vertical right ahead.
(ii) Two green lights vertical on starboard bow.
(iii) Four green lights (2 and 2 vertical) right ahead.
(iv) One green dash every 5 seconds on your port bow.
(v) A vessel painted green showing 3 green balls vertical from her
yardarm.
(vi) Three strokes on a deep toned bell on starboard bow.
(vu) Two strokes on bell right ahead.
(vm) Four strokes on bell on port bow.
31 What measure of reliance can be placed on sound signals in fog?
32 What is (i) a “diaphone” signal, (ii) a “nautophone” signal; (iii)
an “oscillator” signal ?
33. Which are the more reliable, air sound signals or submarine
sound signals?
34. State what you know of wireless fog signals in general.
35. Describe in general terms how W/T hearings are obtained on
board ship from (i) a wireless beacon; (ii) a revolving wireless beacon;
(iii) a rotating wireless beacon.
36. You have made signals of distress to the shore (Article 31),
what do you understand the following reply signals to mean?
(i) A rocket throwing white stars.
(ii) An explosive sound signal showing a white star.
(iii) Two explosive sound signals in succession dropping green stars.
(iv) Three explosive sound signals in succession, 1st a white star,
2nd and 3rd green stars.
(v) A swallow-tailed red flag shown from the shore.
(vi) A triangular red flag shown from the shore.
37. You are compelled to make a landing with the ship’s boat on
a beach, what do you understand the following signals to mean when
shown by the coastguards?
(i) A white flare when held steady.
(ii) A flag waved from side to side.
(iii) Two white flares held steady.
262
nicholls’s seamanship and nautical knowledge
38. What signals are made from a lightship or by the coastguards
on shore when a vessel is standing into danger?
39. Describe in detail step by step the procedure of getting communi¬
cation by means of the rocket apparatus.
40. On what does the success of its operation depend?
41 ' Wila t conditions must an approved line-throwing gun fulfil?
V hat precautions should be taken when getting into rocket line-throwinsr
communication with an oil tanker? 8
42. What is meant by an efficient bell?
43. What is an efficient steam whistle?
44. At what distance should the steam whistle be audible?
45. How are sound signals made in motorships?
46. How are side-lights screened, and what is the breadth of the wick
in an oil side-light?
47. What candle power should electric navigation lights be?
. 48 ' What type of electric lamps should be used and what is the
minimum size of filament?
CHAPTER XIL
PARALLELOGRAM OF FORCES
This is a graphical method of representing the resultant of two
forces acting on a point and the method is applied to such questions in
navigation and seamanship as may lend themselves to demonstration
in this branch of mechanics
The proposition is stated as follows.—If two forces acting at a
point be represented in magnitude and direction by the two adjacent
sides of a parallelogram drawn from the point and the parallelogram
be completed, then the diagonal drawn from the point of application
represents the resultant force m magnitude and direction.
A Canal Boat.—A canal boat is towed from the bank by a rope AR.
This pull is resolved into a fore-and-aft component AP propelling the
boat ahead, and an athwartship pud AQ
which draws her into the bank, but this is
.. a counteracted by the man who is steering
when he pushes the helm, or tiller, two
^ names for the same lever, a little to the
starboard side of the boat, thus causing the blade of the rudder to
incline to port and to keep the boat’s head off the bank.
Current Sailing.—The triangle of forces also comes
into current sailing, as demonstrated by the following
example. A ship is steaming South at 12 knots with
a current setting W.S W. at 4 knots. Find the course
made good by the ship and her effective speed.
Construction .—With a protractor and a scale of
equal parts, draw AB, South 12 miles, and BC,
W.S.W. 4 miles. Join AC . Then AC is the direction
the ship would travel over the ground and the length
of AC is the distance she would cover in one hour.
The parallelogram may be completed by drawing
Al) parallel to BC , and DC parallel to AB.
The course made good is along AC , S. 16}° W., V"
and her effective speed is the length of AC , 13£ miles Fig, %
263
264 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
per Lour, tLe effective speed being the velocities of the ship and current
combined. Triangle ABC is a triangle of velocities.
Moorings.—The illustration shows a ship
alongside a quay. The pull on the headrope
AB is resolved into a fore-and-aft component
AC and a transverse component AD , the force
pulling ahead being considerably greater than
the side pull, as indicated by the relative lengths
of AC and AD.
The pull on the sternrope EF is resolved
into two components EG and EE , the triangle
of forces in this case being EGF. The transverse
component is greater than the fore-and-aft
component so that the rope EF will be a good
breast but not much of a spring, whilst AB.
is a better spring than a breastrope.
Action of the Rudder.—Figures 4 and 5 show re¬
spectively the turning and the retarding effect of a
rudder angled at 20 degrees and angled at 40
degrees. If XY represents the plane surface of
the rudder and PA the fore-and-aft stream
current actmg on it at A , then the water will
be deflected in the direction AQ, because the angle of impact XAP and
the angle of deflection QAY are equal,'and It A is the resultant force
acting at right angles to XY and bisecting angle PAQ .
Produce RA to B so that the length of AB is made equal, in conven¬
ient units, to the force actmg on the rudder. This force will depend
upon the area of the rudder and the velocity of the water impinging
upon it. From A draw AD athwartship and AC fore and aft. Com¬
plete the parallelogram ACBD The length of AD measured from the
same scale represents the turning force actmg on the rudder, and AC the
retarding force which tends to reduce the speed of the ship.
It will be noted for the smaller angle of rudder, Figure 4, that its
turning component is considerably greater than its retarding component,
but that for the larger angle they are almost equal, that is AD—AC
nearly (Fig. 5). The maximum angle of turning efficiency of a ship’s
rudder is between 35 and 40 degrees; if the rudder is set at a larger angle
than this the turning power is reduced and the retarding effect on the
ship’s speed is increased.
The lines on which a ship is designed is an important factor in
PARALLELOGRAM OF FORCES
265
determining her speed of turning. Think of a round flat tub floating in
water and of a deal plank kept floating on its edge by means of a keel.
It is obviously much easier to turn the tub about a vertical axis than the
Fig. 4 —Rudder Angle 20°
plank. Skips are designed on lines between these extremes, and a
short, flat-bottomed, beamy ship turns quicker on her rudder than a
long, deep narrow ship.
/
/
/
/
r"
\
\ —
\
\
\
\
\
\
1
I
f
/
/
Fig. 6.
The Turning Centre of a ship when under way is situated about
one-third her length abaft the stem, and it is necessary to keep this in
mind when manoeuvring in narrow waters as the stem of the ship
sweeps round the circumference of a larger circle than the stem.
Figure 6 indicates the relative diameters of the circles, assuming for the
266
NICHOLAS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
moment the ship to be almost stopped and rotated about her turning
centre 0
The stem sweeps round the circumference of the smaller circle and
the stern post round that of the larger one
i The Turning Circle.—It may be remarked here that when the rudder
is put hard over m a sudden emergency, say a man overboard at A, the
ship’s turning pivot moves round on a circle and the vessel’s keel makes
an angle with the periphery of her turning circle, as indicated m Figure 7,
her stern being thrown slightly outwards by the action of the rudder.
When at position B the helm should be eased and the vessel steered
i
l
i
Fig 7.—The Turning Circle.
for A , because, if the rudder be kept hard over, she will continue turning
through positions G and D. The turning circle will be uniform on the
second round. The diameter of the circle depends on several factors,
the length, breadth and draught of the ship, area of rudder, etc., hut it
is usually about six or seven times the length of the vessel; the time
taken to complete the circle is also different for different ships but
averages about 8 minutes.
True and Apparent Wind.—When a ship is stopped the direction
indicated by a wind vane or by smoke from the funnel is the true windi
During a dead calm no wind would be felt on board a stationary ship,
but when she gets under way a wind, or draught of air, will be felt
as if it were coming from dead ahead. This is an apparent wind caused
by the ship’s progressive motion and this wind velocity will be equal to
the speed of the ship.
PARALLELOGRAM OP POECES
267
When a ship steams at the rate of 10 knots directly into the teeth of
a 40 miles per hour gale (force 8 on the Beaufort Scale), the velocity of
the wind as registered by an anemometer on deck would be 50 m.p.h.,
and, conversely, if she were going in the opposite direction at 10 knots
she would be running before the wind and the anemometer would register
30 m.p.h., that is 40 m.p h less 10 knots The anemometer registers
the apparent wind, which is the resultant effect of the true wind and the
current of air due to the ship’s motion.
Suppose a ship to be stopped, heading North, and the wind to be
blowing from East at the rate of 20 m p h., then the wind would be on
the starboard beam and the steamer’s
smoke would trail to the port beam at
20 m p.h. If the ship now gets under
way and steams North at 10 knots, the
wind would appear to come from the
starboard bow and the smoke would
trend towards the port quarter. But
how far abaft the beam? The par-
of forces will help us ’as
T3U£
Fig 8 —True Wind East;
Apparent Wind N 63° E
allelogram
illustrated m Figure 8.
From the ship A draw AB , West, and mark off 20 parts from* any
convenient scale of equal parts, then draw AC, South, and make it
equal to 10 of the same parts. Complete the parallelogram by drawing
CD parallel to AB and DB parallel to AC. The diagonal AD is the
resultant of the two velocities (wind and ship) and ogives the direction
the steamer’s smoke would go.
AD is the direction of the apparent wind as felt on board the ship,
and its length, measured from the scale of equal parts, will be its velocity.
The apparent wind comes from N. 63° E., velocity 22| m.p.h., and
the smoke will, of course, go S. 63° W.
Another Example .—Given a true wind from N.E , at 10 m.p.h., ship
steaming East, 12 m.p.h. Find the
direction and velocity of the apparent
wind. Draw AB to the S.W. and equal
to 10 units. Draw AC to the East
and equal to 12 units. Join GB.
Then GB is the apparent wind.
Ans .—N. 69 d E., 20 m.p.h.
APPAREMJ
Fig. 9.—True 'Wind N E.;
Apparent Wind N. 69° E.
It will be noted that half the parallelogram is really all that is
needed and ABC is called the triangle of forces
268 N1C1I0LLS S SEAMANSHIP AND NAUTICAL KNOWLEDGE
On board ship, however, it is the apparent wind we experience
and it is the true wind that should be recorded m the log book A
fairly good approximation of the direction of the true wind may be
obtained from the sea as the wind blows at right angles to the normal
wave crest, but our parallelogram may be helpful also.
Example .—The apparent wind is from East with a velocity estimated
at 20 m p.h.; the ship steaming North at 10 m p h. Find the direction
and velocity of the true wind.
Make AB 10 miles due North, and
AC 20 miles due East. Join CB and
complete the parallelogram if desired.
BC represents the direction and velocity
of the true wind S. 63° E, 22£ m.p.h.
This, of course, is the wind which
would be experienced if the ship were
stopped because it is the North-going
FlS erE EaSt ' s P eed of the sb P wh,ch makes the
apparent wind come from a direction
more forward than the true wind.
Boat Sailing.—The principle of sail propulsion may be illustrated
by .a parallelogram of forces, as in the figure, where XY represents the
plane surface of the sail and A the
centre of effort, the name given to
the point where the whole force of
the wind is concentrated. The wind
cannot go through the sail and the angle
of its incidence with che sail at A, angle
XAP is equal to its angle of deflection,
angle YAQ: the impelling force acts
along the line AB which is the bisector
of angle FAQ and is always at right
angles to the plane surface of the sail.
If this force were equal to a wind
velocity of 10 m.p.h., then make AB equal to 10 parts from a con¬
venient scale, and make BC perpendicular to the ship’s fore-and-aft
line drawn through A and we then have a triangle of forces The
parallelogram ADBC may be completed if desired.
AB represents the direction the boat would go if she were a free
agent; AD represents that part of the wind force which pushes the
boat to leeward and AC the part that pushes her ahead. The resistance
Fig II —Sail Propulsion
STRESS OjpT SPANS
269
of tbe water and the shape of the hull are two factors also operating
on the boat, and the object of yacht designers is to build a boat that
will respond fully to the forward component AC and resist the side
component AD.
Cargo Spans.—The tension on the pendants of a span between two
masts can be readily arrived at by constructing an appropriate parallelo¬
gram of forces The illustration shows the usual school apparatus for
demonstrating the principle. The arrangement of pulleys and weights
Fig 12 —Balanced Forces.
is obvious. , A bight of cord has been led over two pulleys and a weight
slung in the centre of it. The weight happens to be 2i lbs., and it is
balanced in equilibrium by a 2-lb. weight at the end of the cord leading
over the left hand pulley and a 1-lb. weight at the end of the cord
over the right hand pulley, thus indicating that the tension on the
left hand cord is 2 lbs. and on the right hand cord 1 lb., the respective
pendants making angles of 22 degrees and 53 degrees with the vertical.
By increasing or decreasing the weights relatively to each other the
270 NIOHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
apparatus will illustrate very clearly the corresponding changes in the
angles formed by the pendants and the tensions on the spans. It will
be recognised that the greater tension will be on the span which is
nearer to the vertical and that the tension on each will be at its maximum
when the span is taut, as seamen say
when the pendants form nearly a straight
line between the pulleys.
The same results may be arrived at
by construction as follows:—
Example —Two pendants form a span
slung between two masts making angles
with the vertical of 22 and 53 degrees.
Find the tension on each arm, or pendant,
of the span when supporting a weight of
2J tons.
Construction — Draw two parallel
vertical hues to represent the masts;
make angles X and Y equal to 22 and
53 degrees respectively. Points X and Y
are placed anywhere on the masts and
represent the positions where the ends of the pendants are made fast
The lines of the angles intersect at A. Now draw AB vertically up¬
wards and equal m length to 2J-ton units from a scale of equal parts.
Draw BC parallel to one span and BD
parallel to the other. The length of AD
represents the tension (1 ton) on the arm
from F, and AC the tension (2 tons)
on the arm from X.
Another Method is to give the lengths
of the pendants and the heights of their
standing ends above the deck as measured
from the rigging plan of the ship, then
draw out the facts to scale and construct
the parallelogram.
Example . — The horizontal distance
between two vertical masts is 80 feet.
The end of one pendant, 60 feet long, is
made fast 100 feet up one mast and the end of another pendant, 50 feet
long, is made fast 70 feet up the other mast. It is intended to lift a
10-ton boiler by using the pendants as span. Find the tension on each.
LOADS ON DERRICKS
271
Const) uciion Make ZTT equal to 80 feet, from a convenient scale,
and erect perpendiculars TFX=70 feet and Z 7=100 feet. With
centre X and radius 50 feet on a pair of compasses describe an arc,
and with centre Y and radius 60 feet describe another arc cutting the
first one at A. Join AX and A Y. The 10-ton weight will be suspended
from A. AB is now drawn vertically upwards and made equal to 10
equal parts to represent unit-tons and not necessarily from the
scale as before as the parallelogram would probably be too big. BC is
then drawn parallel to YA and BD parallel to XA The length of
AD measured in the same units as AB gives the tension on the pendant
A1 (9£ tons), and the length of AC the tension on XA (6 tons).
Fig 15—Derrick Apparatus.
Derricks.—A piece of school apparatus to demonstrate the thrust
on the heel of a derrick and the tension on the span is shown in Figure 15.
A given weight is seen hanging from the end of the derrick, its heel
being fitted into a circular weighing balance which registers the thrust
at the heel, the tension on the span being registered on a flat balance.
The thrust on the heel of a derrick and the tension on the span
leading to the mast due to a weight hanging from the derrick end
may be determined by means of a parallelogram.
Example .—A derrick 48 feet long is kept upended by means of a
span 24 feet long attached to a point on the mast 40 feet vertically
above the heel of the derrick. Find the tension on the span and the
272
nicholls’s seamanship and nautical knowledge
thrust on the gooseneck of the derrick when a weight of 4 tons is hanging
from its top end.
Construction .—Draw the figure to scale by making Xr==40 feet,
then with centre Y and radius 24 feet describe an arc, and with centre
X and radius 48 feet describe another arc cutting the first one at A .
Join AX and AY. Draw AB vertically downwards from A and make
AB equal to 4 units from any convenient scale to represent the downward
force of the suspended weight. Draw BC parallel to the span and CD
parallel to AB; ABCD is the parallelogram of forces.
The tension on the span is given by the length of AD (2J tons),
and the thrust on the gooseneck by AC (4| tons).
24 ft
A weight simply hanging from the end of a derrick is not the usual
condition on board ship. The load is lifted by means of a wire fall
which leads through a cargo gin at the top end of the derrick and down
through a leading block at the heel of the derrick and thence to the
barrel of a winch on deck, the thrust on the gooseneck of the derrick
being thereby more than doubled, as, obviously, when a wire fall is
used the pull exerted by the winch to hold the weight must be equal
to the weight itself and the cargo gin has to bear the double weight.
LOAD ON DERRICKS
273
Example .—Assuming tlie same conditions as in the previous example,
viz , derrick 48 feet long, span 24 feet long, led through a span block
on the mast shackled to an eyebolt 40 feet above the heel of the derrick.
A single fall is led down the derrick through a leading block to a winch
as shown in Figure 17. Find the thrust on the heel of the derrick and
the tension on the span.
Fig. 17.—A Single Cargo Fall.
(i) In parallelogram ABDG , AB is the load (4 fcons)=-40. AD is
the resultant load on block A (7J tons).
(ii) In parallelogram ADEF , AD is 1\ tons, DE is the tension on
the span (2-| tons), AE is the thrust on the derrick (8f- tons).
(iii) In parallelogram XGKH , XG—XH the load (4 tons), XK is
the stress on the heel block (5£ tons).
(iv) In parallelogram YLNM , YL=YM the tension on the span
tons), YN is the stress on the span block (3£ tons).
First, consider the stress at A in the figure due to the load and the
tension on the fall to hold the load.
274 NICHOLES’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Construction .—Make AB and AC both equal to 4 unit-tons. Draw
BD parallel to the derrick and DC parallel to the fall. Join AD.
Then AD is the diagonal of the parallelogram ABDC and represents
the resultant of the two loads acting on the cargo gin, namely, the 4-ton
weight and the 4-ton power exerted by the winch to balance the weight.
The resultant AD is equal to 7£ tons as measured from the scale.
Second.—Consider the stress at A due to the resultant AD and the
tension on the span along A Y to keep the derrick in position.
Construction —Draw DE parallel to the span and EF parallel to
AD. Then AD and AF represent in magnitude and direction two
forces acting at A , and the diagonal AE of the parallelogram ADEF
represents the thrust on the derrick (8| tons) and AF or DE the tension
on the span (2J tons). Thus two parallelograms are required to solve
the problem.
Third.—It may be required to find the stress on the leading block
at X . We would then make XG and XH equal to 4 tons which is the
weight being lifted, and complete the parallelogram XGKH. The
diagonal XK represents the stress on the block X (5f tons), and is the
resultant of the two forces XG and XH acting at X. The angle GXH
would need to be known to construct this parallelogram.
Fourth —The stress on the span block may be found in a similar
way by making YM and YL each equal to DE, which represents the
tension on the span (2\ tons). Complete the parallelogram YMNL.
The diagonal YN represents the stress on the span block at Y (3£ tons).
It is the resultant of the two forces YL and YM acting at Y.
No allowance has been made in the foregoing examples for the weight
of tackle and the derrick, but it will be understood that upending the
derrick increases the thrust at the heel and reduces the tension on the
►
span, also that a derrick swings easier when the heel is stepped vertically
below the point where the span is secured to the mast, that is where X
is exactly below 7.
Another Example .—When the lifting fall is turned into a purchase
the thrust on the derrick is reduced by an amount depending upon the
power gained by the purchase, because the pull on the hauling part to
hold the weight is thereby reduced.
Given the length of a derrick 25 feet; heel to span block on the mast
20 feet; length of span 18 feet; the angle the fall makes at the heel block
leading to the winch is 92 degrees; weight to be lifted 10 tons; lifting
LOAD ON DERRICKS
275
purchase two single blocks, the standing end of the fall being at the upper
block.
Find (1) The stress on the shackle of the upper gin block; (2) the
thrust on the derrick; (3) the tension on the span; (4) the stress on the
leading block; (5) the stress on the span block.
Construction.— (1) Draw the mast, derrick, span, etc., to a convenient
scale. The pull on the hauling part of the fall will be approximately
half the weight as the power gained by the guntackle purchase is two.
Make .45=10 tons; AC=5 tons; draw BD parallel to the derrick and
CD parallel to the fall; join AD, which will be the diagonal of the
parallelogram ABDC\ AD represents the resultant of the two forces
acting at A, viz., the load of 10 tons and the power of 5 tons required
to hold it in suspension. AD is the stress on the shackle (14 tons).
6 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
(2) and (3) Draw BE and AF parallel to the span and EF parellel to
AL> to meet AF. The two forces acting at A, viz., the resultant AD
and the tension on the span AF, are now represented graphically by
the parallelogram ADEF, its diagonal AE being the magnitude of the
thrust on the derrick (17$ tons) and the length of AF or BE gives the
tension on the span (9J tons).
AC = BD ss s tension on fall = 5 tons.
AD the resultant 10J tons
AE the thrust on demck 12£ tons.
AF tension on span 4 tons
{4) To find the stress on the leading block, make XG and XH each
equal to the pull on the hauling part of the fall 5 tons, and complete
the parallelogram XQKS. Join XK.
The length of the diagonal XK represents the stress on the leading
block (7$ tons) which, is the resultant of the two forces acting at X
viz., the fall leading up the derrick and down to the winch.
LOAD OT7 DERRICKS
277
(5) At the masthead make YL and YM each equal to the tension
on the span (9J tons) and complete the parallelogram YLNM Join
YN, then YN represents the stress on the span block (144 tons)
The thrust on the derrick would be considerably reduced if the fall
were led from the derrick head to a lead block at the masthead and then
down to the winch as illustrated m Figure 19.
Assuming the same dimensions as before, viz , derrick 25 feet,
height of span 20 feet up from the heel of derrick, length of span 18 feet.
Find the thrust on the derrick and the tension on the span. (Fig. 19).
In the figure AB is equal to 10 unit-tons, AC to 5 unit-tons. Com¬
plete the parallelogram ABDC. The length of AD gives the resultant
stress at A, 10J tons instead of 14 tons, as in previous example.
Draw DE parallel to the span to meet the line of the derrick AE at
E Diaw EF parallel to AB In the parallelogram ADEF f AE
gives the thrust on the derrick (124 tons) and AF the stress on the
span (4 tons) These measurements may be checked from the scale
on AB with a pair of compasses
By leading the fall from the derrick end through a block at the
masthead instead of straight down the derrick as in Figure 18, the
thrust on the heel of the derrick has been reduced from 17J to 124 tons
in this example, and the stress on the span from 9J to 4 tons, thus
demonstrating the advantage of distributing the stresses as widely as
may be convenient and practical.
Cargo Slings.— Eoca?nple .—A beam 10 feet long and weighing 20 ewts.
is slung by means of a two-legged sling shackled to the ends of the beam
The legs are 6 feet long, find the tension on each leg
m
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Construction. —In fig. 20 (1) make AB =10 feet to represent the
distance between the shackles
(2) Bisect AB at C and erect the perpendicular C D.
(3) With centres A and B and radius 6 feet describe two arcs cutting
each other at D. Join AD and BD.
(4) From any convenient scale, not necessarily the one used above,
make DG—20 units=20 cwts.
(5) Draw GF and GH parallel to BD and AD respectively.
The lengths of DF and DH measured from the same scale give the
tension on each leg, viz., 18*1 cwts.
Calculation —In triangle ACD given AC—5 feet, AD— 6 feet,
angle C=90°. Find angle ADC (G).
Nat. cosec 0=^-r=-=1*2 0=56° 26'. *
AC 5
Triangle 'GFD is isosceles, and if FE be drawn perpendicular to GD
then it will bisect it at E and DE will represent half the load, that is
10 cwts.
In triangle DFE, given DE— 10 cwts., £ 0=56° 26', /.D=90°.
Find DF. DF—DE Sec 0=10 sec. 56° 26'=10X 1*81 =18*1 cwts.
The tension on each leg is therefore 18*1 cwts.
In this example we were given the length of the legs of the sling
together with the load, and were asked to find the tension on the legs,
but the question could be reversed by asking us to find the length of the
legs when the tension on them is given, as in the following example.
Example. —It is required to lift a beam weighing 4 tons by means of
a chain sling attached to a ring, the test working load of the chain
being 3 tons. Find the minimum length of chain for each leg of the
sling when the spread between the shackles is 16 feet.
Construction. —In fig. 21 (1) draw a vertical line DC and make DG
equal to 4 units, from any convenient scale, to represent 4 tons, the
weight of the beam.
(2) With centres D and G and radius 3 units=3 tons, describe arcs
cutting each other at F and H. Join DF and DH and produce the lines
to represent the legs of the sling.
(3) Through D drawXF at right angles to CD, and make DX and
BY each equal to 8 feet from any convenient scale.
♦ The values of natural sines, tangents, secants, etc., are given in Norte’s
Nautical Tables.
CABGO SUNGS
279
(4) Through X and Y draw lines parallel to DG cutting DF and
DH produced at A and B respectively. AB then represents 16 feet,
the spread between the shackles.
(5) The length of DA, or of DB, measured from the same scale,
gives the required lengths of the legs of the sling, viz., 10*7 feet.
Calculation .—First, find angle 0, which is the angle between the
legs of the sling and the perpendicular dropped from their intersection
at D. This might be done as a side issue, because in triangle DFE
DF—3 tons, D2?=2 tons, /.!?=90°. Find XFDE or 0.
DF 3
Nat. sec. 0=—~==~=1*5 0=48° 12'.
DJh 2
Having found 0, make /JJAD equal to (90°—48° 12')=41° 48\
Then AD measured from the same scale as AB will give the minimum
length of the leg. It is easy to calculate it because
AD=AG cosec 0=8 cosec 48° 12'=8x 1*34=10*72 feet.
By making the legs longer their angle of intersection would be smaller
and the tension on each reduced. The same result could be got by
closing in the shackles A and B on the beam thus making the base of
the triangle ADB smaller. *
Example .—A beam weighing 3 tons is being lifted by means of a
sling, the legs of which are each 6 feet long. If the tension on each
leg is 2 tons, find the distance between the shackles, assuming that the
weight of the beam is evenly balanced on the sling.
Construction .—(I) Draw a vertical line DC and lay off DG =3 tons.
(2) Bisect DG at E s and draw EF perpendicular to DG.
280 NICHOLLS’S SEAMANS IT JP AND NAUTICAL KNOWLEDGE
(3) With centre D and radius 2 tons describe an arc cutting EF
at F.
Join DF and produce DF to A so that DA— 6 feet Draw CA
perpendicular to DG and produce it to B } so that CB=CA AB is
the distance between the shackles, viz , 7*9 feet
Fig 22. *
Calculation .—
In triangle DBF. Given DF—2 tons, DE= 1-5 tons, £ 2?—90°,
Find £FDE (0)
A FD 2
SeC0= ^ = r5 =1 ‘ 333 •■• e =U°25'
. In triamjle DAG. DA=6 ft., /_ 0=41° 25'. Z.G= 90°. Find AG.
AG—AD sin 0=6 sin 41° 25'=6x-662 =3-972.
AB= 2 ^40=2 x 3-972 =7-944 ft.
Distance between shackles A and B—7 -94*1 ft.
Example.—A square cargo tray 4'x4', slung by four comer legs
each leg 7 feet long and meeting in a ring at the top, supports a
weight oi 20 cwt. Find the tension on each leg of the sling.
Construction. Make a preliminary sketch to illustrate the question as
in fig. 25. Assuming the load to be evenly distributed on the tray so
that its centre of gravity acts downwards at 0, the middle of the tray,
then each leg of the sling will do the same amount of work. Consider
one pair of diagonal legs, DA and DB t to be doing all the work, and
CARGO SLINGS
281
Fig. 23.
282
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
solve the triangle ADB , just as if AB were a beam as in the previous
examples, but we must first find the length of AB.
Draw fig. 26, AYBX to represent the square tray and note that
AB 2 —A Y 2 + YB 2 = 4 2 +4 2 =32
•'* AB~ V32=5-66 and A0= 2*83 feet.
Fig. 26.
We can now construct triangle AGD to scale as in fig. 27 by making
04=2-83 feet, CD perpendicular to AC, and AD=7 feet. Then con¬
struct the triangle of forces DGF, making DG =20 cwt., and GF parallel
to DH. The length of DF as measured from the scale of weights
gives the tension on each of the two legs DA and DB, viz.; 10'9 ewts.,
assuming that they alone were supporting the load; but the other two
CARGO SLINGS
283
legs are doing the same amount of work and relieve them of half
10-9
their load so that each leg supports ——=5*45 cwts.
JU
O
Calculation .—Having found the length of the half diagonal AC
to be 2*83 feet, the triangle ACD may be solved as follows:—
AD 7
Cosec 0=—= -—=2-473 .\ 0=23° 51',
AC 2*83
In triangle DFE , given 0=23° 51'. DE =10 cwts., /_E= 90°.
Find DF the tension on the sling.
DF=DE sec. 0=10. sec. 23° 51'=10x 1*09=10-9 cwts being
the tension on two legs, or 5*45 cwts on each of the four legs.
Ships’ Cargo Lifting Blocks.—The following extracts are taken, by
permission of the British Engineering Standards Association, from
British Standard Specification Ho. 408, Ships’ CaTgo Lifting Blocks,
official copies of which can be obtained from the Director of the Associa¬
tion, 28 Victoria Street, London, S W.l, price 2s. 2d. post free. The
specification is issued for the guidance of manufacturers who make
steel or iron cargo blocks and wish to subject them to tests preliminary to
their being guaranteed as British Standard Blocks. The principal
conditions of the tests are as follows:-
Definition .—“Block” shall apply to aB ships’ blocks (except malleable
iron and wooden blocks) used for lifting purposes and shall include
284
NICHOLLS S SEAMANSHIP AND NAUTICAL KNOWLEDGE
pin and sheaves, any shackle, eye, hook becket or permanent
attachment to any block
Marking .—Blocks shall be stamped with (a) Maker’s name or trade
mark; (b) Identification number; (c) Safe working load m tons
Safe Woikwg Load —The SWL shall be the maximum load which
m ordinary working can be safely lifted by the block In the case of
single sheave blocks used singly or m combination the load on the pin
or eye of the block shall not exceed half the test load under any conditions
of working.
Factor of Safety —The factor of safety shall not exceed one-fifth of
the calculated breaking load of the material or any part of the block
This factor of safety is intended to allow for additional stress due to
friction, acceleration of load and shock.
Test Load —All blocks to be tested by the application of the following
loads without showing any deformation, visible cracks, flaws or defects.
*
Single sheave blocks.4 times the S W.L.
Multiple sheave blocks up to 20 tons, 2 times the SWL.
„ „ 20 to 40 tons, S W.L. +20 tons.
„ „ over 40 tons, 1-J times SWL.
Sheaves .—The diameter to be the outside measurement of the
sheave. Pins to be secured to prevent rotation. Depth of groove to be
not less than the diameter of the rope. Angle of flare of groove 50° to
60°.
Where the angle of embrace is 90° or more it is recommended that
the minimum diameter of the sheaves for various sizes of rope shall be as
follows:—
Under 2" wire. 10" sheave.
2" to 21" „ 12" „
21" to 3" „ 14" „
3" to 4" „ 16" „
Over 4" „ 18" „
The mimmum diameteT of sheaves for any
other conditions should be not less than four
times the circumference of the wire used.
All nuts to be securely locked and sheaves
and swivel heads to be provided with sufficient Angle °* Embrace 90 •
lubrication.
- Bechets to be capable of carrying at least half the load on any one
sheave.
CAEGO SUNGS
285
Shackles .—Shackles to be legibly stamped with their safe working
load and their identification number.
Information as follows to be supplied when ordering cargo lifting
blocks. Description of block Fittings. Number of sheaves Type of
sheave. Size of rope. Safe working load. Remarks.
QUESTIONS.
1. Sketch a derrick and name the gear on it.
2. How would you go about putting the gear on a derrick and getting
it upended ready for working cargo?
3 What is meant by the “parallelogram of forces”?
4. Draw the following to scale:—
Length of derrick, 50 feet.
From heel of derrick to span on the mast, 40 feet
Angle between derrick and mast, 30°.
Weight suspended from the end of the derrick, 3 tons
From your figure find the approximate thrust on the heel of the
derrick and the strain on the span.
Aits. —3*8 and 1*85 tons.
5. The same derrick is lowered to make an angle of 60° with the
mast. What will the relative thrust and strain be now?
A?is. —3*8 and 3*3 tons.
6. A span between two masts is formed by two pendants, one
pendant makes an angle of 40° with the vertical and the other makes
an angle of 60° with the vertical. A load of 6 tons is suspended from
the span, find by construction the load on each pendant.
Ans —5*5 and 3*9 tons.
7. A span is formed by two pendants from two masts, one at an
angle of 30°, the other at an angle of 80°, to the vertical. Find the tension
on each arm of the span when supporting a weight of 4 tons.
Ans. —2| and tons.
8. A derrick at an angle of 50° is supported by a topping lift at an
angle of 40° to a vertical mast. Find the thrust on the derrick and the
tension on the lift when a weight of 6 tons is hanging from the head of
me derrick.
Ans. —3J and 4| tons.
286
NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
9. From the following information construct a figure to scale and
by means of triangles of forces find (1) the stress on the cargo gin;
(2) the thrust on the derrick; (3) the tension on the span; (4) the load
on the span block; (5) the load on the leading block at the heel of the
derrick when given length of derrick 25 feet; heel to span block on mast
20 feet; length of span 18 feet; angle the fall makes at the heel block 92
degrees; weight to be lifted 10 tons, using a single wire fall.
Am. (1) Stress on gin block 18£ tons.
(2) Thrust on derrick heel 22J tons*
(3) Tension on span 9 tons.
(4) Load on span block 13-J tons,
(5) Load on heel block 14 tons.
10. What do you consider to be the best arrangement of derrick
ot derricks when loading or discharging a bag cargo?
11. Describe the cargo gear you would rig when loading (a) slings
of goods weighing about 5 cwt.; ( b ) heavy goods weighing 1 ton per sling.
12. A beam weighing 30 cwt. is supported in slings attached to
shackles on upper flange of beam and 12 feet apart. If the legs of the
sling are 8 feet long, find the stress on each leg.
Am. 22| cwt.
A Cargo Gin.
Fig. 28.
A Cargo Hook,
CHAPTER XIII,
THE EFFECTS OF THE SCREW RACE UPON THE STEERING OF
STEAMSHIPS,
The turning effect of the rudder depends upon the force and direction
at which the passing flow of water impinges on the rudder plate, already
referred to under “Parallelogram of Forces,” page 264.
The free flow aft of the water along the ship’s side is interfered with
m the vicinity of the rudder by the local currents set up by the revolving
screw and the streamline form of the vessel. Experiments are still
being earned out with balanced, semi-balanced and unbalanced rudders
to discover the ideal streamline shape and the position and the method
of their suspension, so that they may react m the most effective way to
the actual flow of water in their immediate vicinity It is impossible to
determine in practice the ultimate direction of this current as it is the
resultant of a complicated spiral commotion set up by the rotating
propeller, modified bv the horizontal flow of water due to the steerage
way of the ship, so that deductions arrived at by theoretical analysis
are, more or less, of an empirical character.
The seaman is only concerned with the manoeuvring of Ms ship,
her responsiveness to rudder action in turning to port or starboard
when going ahead and going astern. The theoretical steering effect
may not be exactly the same as that experienced in practice. The
successful pilot finds out what the sMp will do under stated conditions
and then avoids, if possible, trying to make her do something else.
We shall discuss the steering forces under three heads:
I. The Wake Current.
II. The Transverse Thrust.
III. The Screw Race (a) Transverse Component; (6) Fore-and-aft
Component.
I.—The Wake Current.
The Wake Current is the simplest to comprehend. Hold a flat
piece of wood vertically in the water, pull it forward first edge on and
then side on. Note the current effect, particularly when it is side on,
and observe the hollow, or cavitation, behind the wood and how the
287
288 NICHOLLS S .SEAMANSlIir AND NAUTICAL KNOWLEDGE
water swirls round the edges and follows up behind m an endeavou*
to fill the cavity This follow up is called the Wake Current *
The same effect is produced by a vessel with or without a propellei
when being towed. She drags “dead” water after her to fill up the hole
caused by the volume she has displaced. This current is strongest
at the surface and gradually diminishes to zero strength at the keel
level; it is non-existent when the vessel is stopped and increases
in velocity as the ship’s speed increases The wake current is more
pronounced in vessels of full form than m those of fine lines This is
the chief reason why flat-bottomed, square-sterned barges are difficult
to steer as the wake current following up behind is strong and neutralises
more or less the effect of the flow aft due to the vessel’s headway.
Effect-—
Going ahead—The wake current reduces the steering power of
the rudder.
Going astern—No effect; it does not exist at the stern.
II.—Transverse Thrust.
The obliquity of the blades sets up a current which may be resolved
into a transverse component and a fore-and-aft component; the transverse
force or thrust exerted by the screw is, however, small m comparison
to the fore-and-aft force which drives the ship ahead.
Effect of Right-handed Propeller .—
Going ahead-—Stem cants to starboard.
Going astern—Stern cants to port briskly.
The athwarthship component of the obliquity of the screw does not
account for the slewing of the stern as, in theory, the thrust to one
side should be equal to the thrust to the other side because the upper and
lower blades pass across equally ea'ch way in the course of a revolution,
the pressure low down being practically equal and opposite to the
pressure high up.
B it the propeller chums and breaks up the water near the surface
to a greater extent than deeper down, with the result that the lower
blades cut through more solid water and have to overcome greater
resistance than the upper ones. Think of a propeller half immersed
The upper half cuts through air, the lower half through water, and the
difference of these transverse pressures slews* the stem to starboard
when going ahead, but more briskly to port when going astern, as the
forward flow of water from the propeller washes up against the hull
and retards the stem way of the ship, thus reducing the lore-and-art
component relatively to the transveise component.
UP
DOWN
/✓//'//// ■ V>V v V'\V
v • ■ -
..... >.$ i ;
, > f > . ! , i 1
WV\\ *\\
V/iJ 1 •"
I / / / / / /'tvN I ' j t 1 I I
■ » i i 1 \ \ ^ j J / t i i
\ \ \ \ \ '
\\>«*
£>>
v\V
sN N \ \ \
N \ N \ N * '
/ // / /> 'v N N N \ \ \ \
'•!"!/'/?' 'I'll Hi
1 / j H I
/ f 1 I
FIG 1
SCREW RACE—RIGHT HANDED
PROPELLER GOING AHEAD
Green lines represent the flow of the starboard water-
Red lines the flow of port water.
SCREW RACE
289
III. —The Screw Race.
The screw worms its way through the water and, in doing so, creates
two spiral currents which corkscrew or curl sharply round each other
and criss-cross at different levels in the screw aperture whilst, at the
same time, the body of rotating water is driven astern by the thrust
impulse imparted to it by the after side of the blades when the engines
are going ahead. The twisting particles of water may be resolved into
two components, transverse and fore and aft.
Figure 1 is an effort to illustrate the spiral flow of the layers of
water acting against the rudder. Imagine the port blades of the propeller
to be coming up and the starboard blades to be going down, as they do
when going ahead with a right-handed screw
The downstroke to starboard induces and urges the water to pass
diagonally across the aperture from starboard to port under the boss
and to curl sharply upwards and back again, washing against the port
upper half of the rudder in its endeavour to get back to the starboard
side of the ship. That is to say, the water enters on the starboard
side, crosses to port below the boss, curls up again and is discharged
higher up against the top h'alf of the port side of the rudder.
This transverse component acting on the rudder pushes the stern
to starboard.
Simultaneously, the upstroke to port induces and throws the water
diagonally across the aperture from port to starboard above the boss,
the spiral impulse causing the water to curl sharply downwards and back
again and to wash against the starboard lower half of the rudder in
its endeavour to get back to its port side of the ship.
That is to say, the water enters on the port side, squelches across
to starboard above the boss, and is discharged against the starboard
side of the rudder low down when finding its way back to port.
This tranverse component acting on the rudder pushes the stem
to port.
So here we have a double transverse effect acting simultaneously
on opposite sides of the rudder, a flow of water acting on its starboard
side low down and another flow acting on its port side high up; but
the deeper flow acting on the starboard lower half predominates and
urges the ship’s stem to port.
The rotary effect of the screw race has been demoristrated by an
interesting experiment, in which a Judder was horizontally divided into
two parts—an upper and lower half—each part being free to move
In response to any influences. When the screw (right-handed) was
290
NICHOLLS’S SEAMANSHIP AND NAUTICAL. KNOWLEDGE
working ahead, the lower half was found to be inclined nearly 10°
to port, and the upper half at a slightly less angle to starboard. A
whole undivided rudder, which was free to move in either direction,
was found—when the screw was working ahead—to incline a little to port.
(h) Fo? e-and-aft Component .—The after face of the blades is the
pressure surface of the screw when going ahead. The particles of water
are pushed astern past the rudder and give an underway steering effect
immediately the engines are started and before the ship gathers headway.
Screw Race Ejfect —
Going ahead— (a) Transverse component cants stern to port.
(b) Fore-and-aft component gives the steering
effect of headway.
Going astern— (a) Transverse component cants stern to starboard
(b) Fore-and-aft component gives steering effect
of sternway.
SUMMARY WITH RUDDER AMIDSHIPS -
Effect when starting from rest
Effect when going
Ahead
Astern
Ahead
Astern
I. Wake Current
No effect
No effect
Reduces
No effect
Current non-
steering
existent
power
Weakly at
first but
II. Transverse
strongly as
ship gathers
headway
Stem to star-
Stem to port
Stem to star-
Stem to port
Thrust
board
board
III. Screw Race
Strong
Strong
Fairly strong
Strong
[a) Transverse
Stem to port
Stem to star-
Stem to port
Stem to star-
Action
board
board
Weak
Weak
I Weak
Weak
(b) Fore-and-aft
Gives steering effect
Gives steering effect
Action
of headway '
of stem way
of headway
of stemway
Probable
Head swings
Head goes to
Head goes to
Head goes to
Resultant of
to port
starboard
pdrt
starboard
I., II., III.,
Can be coun-
Cannot be
Can be coun-
Cannot, as a
acting
teracted by
counteracted
teracted by
rule, be
together
rudder if
by rudder
rudder if
counteracted
desired
desired
by rudder
unless consid¬
erable stem¬
way is gath¬
ered
The screw exerts its greatest turning effect when the engines are
going slow ahead or full astern, the radius of the ship’s turning circle
increasing with her speed through the water.
ACTION OP RUDDER AND PROPELLER
291
The churning of the crater is greatest when starting the engines
from rest, particularly when going astern* and especially so when
reversing from full ahead to full astern. The excessive vibration then
felt throughout the ship is due to cavitation, the blades following each
other m quick succession into the same “hole” before the water has time
to effectively fill the cavity.
In view of the importance of reversing the engines when going ahead,
the following extracts are taken from the Report of a Committee of the
British Association appointed to discover the best rules for the guidance
of ships’ captains in endeavouring to avoid collisions (see White's Naval
Architecture)
“The distance required by a screw steamer to bring herself to rest
from full speed by a reversal of her screw . . . generally lies
between four and six times the ship’s length. It is to be borne
in mind that it is to the behaviour of the ship during this interval
that the following remarks apply:—
“It is found an invariable rule that during the mterval in which a
ship is stopping herself by the reversal of her screw, the rudder
produces none of its usual effects to turn the ship; but that under
these circumstances the effect of the rudder, such as it is, is to
tom the ship in the opposite direction from that in which she
would turn if the screw were going ahead. The magnitude of
this reverse effect of the rudder is always feeble, and is different
for different ships, and even for the same ship under different
conditions of lading.
“It also appears from the trials that, owing to the feeble influence of
the rudder over the ship during the interval in which she is
stopping, she is then at the mercy of any other influences that
may act upon her. Thus the wind, which always exerts an
influence to turn the stem or forward end of the ship into the
wind, but which influence is usually well under control of the
rudder, may, when the screw is reversed, become paramount, and
cause the ship to turn in a direction the very opposite of that
which is desired. Also the reversed screw will exercise an influ¬
ence which increases as the ship’s way is diminished, to turn the
ship to starboard or port, according as it is right or left-handed;
this being particularly the case when the ships are in light
draught.
“These several influences, the reversed effect of the rudder, the
effect of the wind, and the action of the screw, will determine
292 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
the course the ship takes during the interval of stopping They
may balance, in which case the ship will go straight on; or any
one of the three may predominate and determine the course
of the ship. The utmost effect of these influences when they all
act in conjunction—as when the screw is right-handed, the helm
starboarded, and the wind on the starboard side—is small as
compared with the influence of the rudder as it acts when the
ship is steaming ahead.”
SHIP WITH HEADWAY/FULL AHEAD TO FULL ASTERN.
Discuss the Steering Effect of Propeller and Rudder.
This case may arise suddenly through force of circumstances to
avoid colliding with something close ahead. The turmoil in the pro¬
peller aperture is rather confused but is something on the following
lines.
The normal current flowing aft past the rudder is interrupted by the
reversed screw (i) discharging water forward m opposition to it, and (li) by
inducing a forward flow which acts on the after side of the rudder.
These two forces gain strength as the screw continues to reverse and
eventually they predominate and swamp the normal flow due to headway,
but at first the turning effect of the rudder is doubtful and it should be
kept amidships, for then it won’t be on the wrong side, bujb when the
vessel gets stemway it should be angled to one side or the other as
required. One thing is certain to happen at first, viz., the ship’s head
will fall off to starboard.
The distance the ship will carry her headway is perhaps of more
importance in an emergency than the arc her head will describe when
the engines are rung from full ahead to full astern. It depends on the
ship’s initial speed. The average 10-knot cargo vessel of 8000 tons
deadweight will probably bring up in about six times her length, and
if going half speed this distance will be reduced to about one-half. It
is interesting to note that when the backwash from the reversing pro¬
peller reaches forward to about the navigating bridge the vessel’s, head¬
way is practically stopped, assuming the bridge to be a little forward of
amidships as it usually is. This approximation is a guide when stopping
the ship at night time for any purpose and no objects in sight.
To turn a single screw steamship short round. — A consideration of
what has already been stated will show that a steamer with a righc-
Handed propeller can be turned more easily with her head going co
ACTION of rudder and propeller
293
starboard than in the other direction. When necessary to turn short
round put the rudder to starboard, and the engines full speed ahead.
The screw race will press against the rudder, even if the vessel has no
headway, and she will cant to starboard. Before she gathers too much
headway the engines should be reversed to full speed astern, the helm
being shifted accordingly so as to obtain the benefit of the suction current.
Before she gathers too much sternway go full speed ahead again with
rudder to starboard and so on, alternately, until round.
It is advisable to have an anchor ready for dropping when turning
short round in narrow channels and to know that there is sufficient
depth of water when manoeuvring close to the banks.
TWIN SCREWS
The effects of twin screw propellers are not so complicated as those
of single screws. It is only necessary to take into account (1st) the
current caused by the screw, and to consider whether it is a discharge
current acting against the fore side of the rudder, or whether it is a
suction current drawn m against its after-side: (2nd) the transverse
thrust of the screws.
As the screws revolve in opposite directions* when both are going
ahead at the same speed, there should not be any turning effect from
the transverse thrust of the screws, and if the helm is ported or star¬
boarded they will assist the action of the rudder Also when the screws
are going astern, the current drawn in by the propellers acts on the after-
side of the rudder, and if the ship is also moving astern they assist the
action of the rudder.
To turn a twin screw steamship short round.—This is done by going
ahead on one and astern on the other; the bow of the ship then turns
towards that side on which the screw is going astern. By regulating
the speeds of the propellers' so as to prevent the vessel getting headway,
the steamer can be made to turn round in her own length. When
turning short round in this way the helm should be kept amidships
If the starboard screw is right-handed and the port one left-handed,
the transverse thrust of both screws will assist m turning the ship short
round in either direction.
TURNING CIRCLES.
Very meagre information seems to be available regarding the
turning circles of merchant ships and the time taken by them to
•The starboard one is generally right-handed and the port one left-handed.
294
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
complete a round turn, probably owing to the fact that much depends
upon the trim and load displacement of the ship. The average time to
complete the first turn works out at about 8 minutes. In the case of a
vessel of 2000 tons on trials she turned through 180° in 3 minutes and
360° in 7J minutes, the initial speed was 14 knots which was reduced
to about 7 knots when the circle was being completed, the diameter of
her turning circle worked out at 6 times the length of the ship.
The trials of a Bibby liner fitted with an Oertz rudder by the Marine
Navigation Company, London, worked out as follows:—
Turning circles with rudder hard over. Speed 1 ljknots approximately.
Turning to port
\ circle lm 55s
i „ 3m 40s
f „ 5m 36s
Full circle 7m 46s
Turning to starboard
lm 45s
- 3m 32s
5m 37s
7m 45s
Average time to throw the rudder from hard over to hard over, 20
seconds.
SHIP HANDLING.
1. What would you particularly look to in seeing if all was ready in a
steamship for going out of dock and proceeding to sea?
Engine-room telegraph, steam whistle or siren, steam steering
gear, winches, etc.; also see there were no boats, lighters, lines, etc.,
about the stern likely to foul the propeller. If possible I would get the
derricks lowered and secured, the hatches on and battened down.
Also I would have all lamps trimmed, patent log ready for use, hand
lead line and heaving lmes handy, fenders ready, mooring ropes all
clear for coming in or carrying along. Charts and all gear ready in the
chartroom. Everything in order on the bridge.
2. What information does a pilot require when he comes on board?
Full details regarding any special features of the ship, particularly
her steering qualities and the working of her engines, also her power
when they are going astern. The draft of water. The deviation of
the compass.
3. What effect has a right-handed propeller on a steamer’s course when
going ahead with helm amidships; also when going astern?
Her course would be directed to port when going ahead, and her
head would cant to starboard when going astern.
SHIP HANDLING
295
4. How does a steamer cant when her engines are started ahead or
astern—no wind or tide?
Assuming that she has a right-handed propeller: when going ahead,
her stern will cant to starboard and her head to port. When going
astern her stem will cant' to port and her head to starboard. This
turning effect is caused by the transverse thrust of the propeller. It is
greatest when the engines are first started, diminishing as the vessel
gathers way, but is not entirely lost.
5. How would you turn a steamer short round?
Rudder for starboard swing and put the engines full speed ahead.
As she gathers headway, full speed astern, and rudder amidships.
Carry on m this way until she is round.
6 Is the propeller m a single screw steamer right-handed or left-handed?
Generally right-handed. I should always assume it to be so unless
the examiner distinctly mentioned a left-handed one.
7. A man falls overboard; wbat vould you do?
Stop the engines, throw him a life-buoy, put the rudder hard over to
the side from which he fell, hand aloft to watch him Start up the
engines again and steam right round in a circle, meantime getting the
emergency boat swung out, maimed and ready for lowering. When
the ship is heading for the man steady the helm, ease the engines and
get as close to him as possible, stop the ship, drop the boat and pick
him up.
8. Wbat would you do if a man fell overboard in heavy weather?
Heave him a life-buoy. Stop the engmes. Send a man aloft to
watch him if necessary. Manoeuvre the ship to windward of the man,
at the same time getting ready a boat which will be a lee one when you
are in position for lowering. Spread oil to make a smooth. Heave the
ship to, man the boat and lower away. Steam down to leeward,
again spreading oil, and make a lee for the boat. Have a boatrope
fore and aft with men to tend it ready for the boat as she comes alongside.
Have good men at the falls, watch a chance to hook on, get her up again
as quickly as possible.
9. In hazy weather you discover land ahead and on each side. What
action would you take?
*Come full astern on the engines. Turn the ship short round and
steam out on a course opposite to that on which I came in. Take
frequent soundings and proceed with caution.
296
NlCHOLLS'S SEAMANSHIP AND &AUTICAL KNOWLEDGE
10. What would you do if you sighted a fog bank right ahead?
Reduce to a moderate speed. Station a hand on the look-out.
When I enter the fog make the fog signal prescribed for steam
vessels under way with way upon them.
11. You are proceeding at a moderate speed. You have a light wind right
aft. A blast on a foghorn is heard fine on the port bow What
would you do?
Stop my engines and navigate with extreme caution. It is a vessel
on the starboard tack crossing. Keep a sharp look-out for her. It may
be necessary to alter my course or ring full ahead or full astern on the
engines.
If we came within sight of one another and I had to alter my course
or go full speed astern to clear her, I should indicate my action by a
short blast or blasts on the whistle or siren according to Article 28.
12 What is meant by a vessel being wind-rode ?
When a vessel at anchor is riding head to wind she is said to be
“wind-rode.”
13 What is meant by a vessel being tide-rode?
When she is lying head to tide she is said to be “tide-rode.”
11 When is a vessel said to be riding weather tide?
When she is at anchor, and the wind is against the tide.
15 When is she said to be riding lee tide?
When the wind and tide are in the same direction.
16 When coming to an anchor in fine weather, and only intending to stay
there for a short time; how much cable would you give her?
If there was no tide, four times the depth of water would be enough.
In a tideway I should give her more, the actual amount depending
on the strength of the tide and the nature of the bottom. In good
holding ground I should not want so much as in ground where the
holding was poor.
17 In what direction would your anchor lie if you were riding head to
wind and tide?
About a point on the bow. I should keep it there by giving her a
small sheer with the rudder away from the anchor. If the port anchor
were down, wheel to starboard would do it. If the starboard anchor
were down, turn the wheel to port.
TENDING SHIP AT ANCHOR
297 *
!8 Suppose m a strong wind or tide she “yawed” about, frequently
breaking her sheer;, what would you do?
Have a man at the wheel, and steer her as if under way.
19 What is the best position to have the shackles when yoiJ are moored
with two anchors in a tideway?
They should be where they would be handy to get at in the event
of having to unshackle for the purpose of clearing hawse. Close abaft
the compressor or windlass would be a good place. There would then
not be much cable to pass round.
20. Why are ships moored with two anchors *
Because when moored with two anchors placed in opposite directions
they do not cover so much ground when swinging at each turn of the
tide. They would ride to one anchor on the flood, turn round practically
in their own length, and ride to the other on the ebb
21. In what direction should the anchors lie when moored in a tideway?
In the direction of the ebb and flow of the tide The one to which
the vessel was riding should be a little on one bow, and the other one
fine on the opposite quarter.
22. How often does a vessel swing when she is anchored or moored in a
tideway?
She swings at every turn of the tide in moderate weather. That is
at intervals which will average about 6| hours.
23. Does it matter which way she swings?
Yes. She must always swing round on the same side of her two
anchors. If she does not, she is liable to get turns in her cables.
24. What would you do to ensure her swinging the right way?
Give her a sheer with the helm just before slack water. The new
tide would then catch her on the quarter* and swing her round in the
same direction in which I had sheered her.
25. Suppose through failing to tend her, or for any other reason she
swung round the wrong way; what would happen?
The first swing would cause a cross in the cables, the second swing
would produce an elbow, and if she swung round the wrong way three
times there would be a round turn.
• 298
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
26. Having got a turn in the cables, how would you take it out; ox in
other words how would you “clear hawse”?
At slack water I would lash the two cables securely together, below
the turns if possible. Lead a good wire through the forecastle-head
warping chock and shackle it on to the cable I was not riding by. Heave
it tight and make it well fast. Reverse the windlass, unshackle the cable,
and take the turns out by passing the end round the cable I was ndmg to.
Shackle on again, heave tight, and screw the windlass up Take off
the lashing and wire.
27 What would your duties be, as second mate, when keeping anchor
watch at night?
To see that the Regulation lights were burning brightly, keep a
good look-out and specially watch for any signs of the vessel dragging
her anchor. Be sure that the other anchor was all clear and ready in
case of emergency. See that no unauthorised boats comte alongside the
ship. Keep the other members of the anchor watch handy on deck.
Carefully attend to any standing orders.
28. How would you know if the ship was dragging her anchor?
By watchmg the bearing of two fixed hghts or objects in line. Beam
bearings are the best. If they change, the ship is dragging.
By dropping the deep sea lead on to the bottom, and noting if it
trails ahead of the ship.
By putting my hand on the cable before the windlass. If she was
driving I should feel the vibration caused by the anchor dragging along
the bottom. Should also listen for any sound of the anchor dragging
by applying my ear to the cable. Both these methods, however, may
be deceptive because vibration and sound are often caused by the cable
moving on hard ground even though the anchor is holding well.
Also, in soft mud the anchor might drag without causing any
vibration or sound.
29. What would you do if you found the anchor was dragging?
Give her more cable. If I saw that it was urgent, I should not
hesitate to let go the second anchor. Send a message immediately
to my senior officer or to the master.
SO. How would you carry out a kedge and warp in a boat?
If I was carrying it out to windward or against* the tide I should
coil or fake the whole length of the warp down in the boat clear for
TENDING SHIP AT ANCHOR
299
running. Lower the hedge down into the boat, landing the crown and
arms on to a plank lashed across the gunwales well aft, and having the
stock in a vertical position over the stern. Bend the end of the warp
on to the hedge. Pull the boat out to the desired position, be sure that
the warp is clear, and drop the hedge. This is best done by turning or
sliding it over the quarter. It is much easier than topping it up over
the stem, and less likely to result in a foul anchor. I should pay the
warp out from the boat as I pulled back to the ship and pass the end
on board. Should not forget to buoy the anchor before dropping it.
When carrying a kedge out to leeward or with the tide, after making
the warp fast to it, I should hang it over the stern by means of a sliprope,
but instead of coiling the whole of the warp down in the boat should
take only a few fathoms to slack away if necessary, making them pay
it out from on board the ship as I pulled away.
This would save me the work of dragging the floating warp back
to the ship against the wind or tide; in a ship’s boat it might not be
possible to do it.
31. What is the length of the buoy rope, and how should it be made
fast to the anchor?
It must be long enough for the buoy to float at high water, and to
ensure that the buoy is not run under in a strong tide.
It should be made fast at the crown of the anchor by means of a
clove hitch with one part on each side of the shank, and finished off
with two half hitches.
32. What is the object of buoying the anchor?
To mark its position, and to provide a means of recovering it if
the warp should be carried away. The buoy rope, of course, must
be good enough for the job.
33. You come to anchor in bad holding ground. What precaution
would you take to ensure against dragging?
Give her a greater length of cable than I should if the holding ground
was good.
34. In that case, what would you do at slack water if there was no wind?
Heave in the cable until short. When the vessel swings with the
new tide veer away again until I am riding to the required length.
300
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
35. Coming in against the ebb tide, how would you make fast between
two mooring buoys, head out?
If the tide was not too strong I should steam slowly up past the lower
buoy, keeping both buoys on my port side. When far enough ahead run
a good line from my port quarter on to the upper buoy. Make it fast
to the bitts or take it to a good winch ready for heaving close up. The
ship will then swing round with the tide. A little time would be saved
by going alternately astern and ahead on the engines. When swung,
make her well fast by the stern to the upper buoy. Get my cable or
some good headlines on to the lower buoy.
If there was much tide I should steam up to the lower buoy, run
some good headlmes to it or shackle my cable on, and wait for slack'
water. When the new tide made, the ship would swing round to it I
could then get my stern moorings on to the upper buoy.
BERTHING, ETC.
It is not possible to give definite instructions for bringing a steamer
alongside a wharf, dock, or pier, which will apply to all cases. Much
will depend upon local conditions, set of tides or currents, conveniences
available for use in the shape of buoys, dolphins, etc. The following
general suggestions should, however, be noted, and will apply to most
cases:—
Slack water is the best time—the stronger the tide or current the
more difficult it will be.
If there is any tide or current running the vessel should be stem on
,to it. She should be kept nearly parallel with the wharf, with the bow
slightly canted towards it, and gradually brought alongside.
If the wind or tide sets' the vessel towards the wharf, lines must be
run out to buoys if available, so as to ease her down to her berth. If no
buoy or dolphin is available take the vessel a little ahead of her berth 1
and drop the off-shore anchor, and ease her alongside with the cable.
In any case, when a convenient distance from the shore and stem on
to the tide, run a spring out ahead from the bow, and also breastropes
from the bow and stern. Heave in enough of the spring to keep her
from dropping astern of her berth, and then heave her steadily in with
the breastropes. Remember that heaving in a bow breastrope will tend
to make the stern go out unless there is a stem breastrope to prevent
it, and vice-versa. The vessel must only be allowed to cant very slightly
towards the shore. The helm can be used when stem on to the tide
BERTHING AND MOORING
301
just as if under way, and the ship sheered towards or away from the
shore as may be necessary.
Note carefully if there are any overhanging obstructions likely to
foul the ship’s rigging, davits, bridge, etc , and take corresponding
precautions. (See detailed questions further on.)
Getting away from Alongside a Wharf , Pock, Etc.
If the vessel is stem on to the tide.—Have a spring from aft made
fast to the wharf well forward, and a breastrope from the bow. Cast
off the moorings, and the weight coming on the spring her bow will cant
out, use the rudder to assist m canting ship’s head as desired. When
the bow cants out keep a check on the breastrope, which will bring the
stern out, when clear, the engines can, if necessary, be used.
If the vessel is stern on to the tide.—Have the spring from forward,
the breastrope from aft. and bring her out stern first
Care must be taken not to use the engines until clear, and also to
allow for the effect they may have m bringing her stern m or out.
Coming Alongside a Wharf, Docking, Etc.
1. You are coming up a river on the flood tide, how would you go
alongside a wharf?
Have my anchors clear and my heaving lines, fenders, and mooring
ropes all ready for use. When a little way past my berth turn my
ship round and stem the tide. Steam slowly towards the wharf. Give
her a slight cant in as I approached it, using my engines as necessary.
Get a good headline ashore and make it fast. When the weight comes
on it she will drop alongside. See that she is properly moored.
2. Coming up on the flood, how would you get alongside if there was a
strong wind blowing across the river directly on to the wharf?
* Bound her to and stem the tide. Steam slowly into a good Weatherly
position ahead of my berth. Let go my offshore anchor. Bun a
good headline ashore on to the wharf and make it fast. Ease away my
cable. The weight will gradually come on to the rope, and she will
drop alongside. Mind my fenders.
3. How would you get alongside a wharf if you were coming up a river
on the ebb tide ?
Steam slowly up towards the wharf, having just enough way to
stem the tide and carry me over the ground as I approach it. When
302
NICHOLLS S SEAMANSHIP AND NAUTICAL KNOWLEDGE
abreast of my berth give her head a slight cant in and stop my engines.
Run a good headline ashore and make it fast, having a second one all
ready. As the weight comes on the headhne she will drop alongside
with the tide. Make her well fast.
4. What precautions would you take if the tide was very strong ?
Steam up a little ahead of my berth and drop my offshore anchor.
Run a good headhne ashore. Ease her back alongside with the cable
and headrope. Pay particular attention to my fenders and moorings.
5. What general precautions would you take as regards moorings, etc.,
when lying at a wharf?
See that my headlines led well ahead, and my sternlines led well
astern, and that I had a good drift on my backsprings. Have good
breastropes from my outside bow and quarter. A paunch mat on my
stem and other chafing gear where it was necessary. Tend my breast-
ropes very carefully if there was much rise and fall of tide, easing them
and tightening them up again as required. Should not forget my
gangway. See that I had suitable fenders and that they were properly
placed. In addition to my ordinary moorings should have a stout wire
ready both forward and aft in case it came on to blow hard. When
no cargo was being worked should see that a good watch was kept
throughout the night. Have an officer on active duty if conditions
demanded it.
6. You have arrived off a dock on the top of high water; how will you
get in?
Steam slowly towards the pierhead making allowance for the wind
by keeping in a good weatherly position.
Have my anchors ready for letting go if
necessary, also all lines and fenders handy.
Give her a cant in and straighten her up
as I approach the entrance. There will
_ be no need to go alongside before entering
the locks. Run a good line ashore on to
the pierheads from each bow as soon as
possible, also one from each-quarter when
near enough, weather ones first. Come
slowly ahead paying attention to dock-
master’s orders.' Pierhead men will attend
Fig &
to my lines ashore. Look out for tugs, barges and other small craft (Fig.2.
DOCKING AND MOORING
- 303
7. You are coming up a river, on the hood. How would you dock your
ship with the tide running right across the entrance?
I would turn round and stem the tide. Come alongside the lower
pierhead (A) and get a line ashore from my inside bow. After
getting alongside and if no tug available I would run a line from the
outside quarter to the opposite
knuckle (B) to heave her stern
up against the tide. Engines
ahead and check round the
knuckle using bow line as
required and heaving on the
quarter rope.
Alternative method. If
the tide is strong, come
alongside at upper side of entrance (B), get port quarter and bow ropes
ashore, then drop astern, hist using quarter rope to check her in to
the entrance stern first, then the bow rope to keep the vessel from
being swept too far round by the tide.
8 Coming up a river you have arrived outside a dock with the ebb tide
coming down but are just in time to get in. How would you
dock her?
Give her a cant in under very easy steam, run a good line ashore
from my inside bow; and drop gently alongside the pierhead. Should
not waste any time, but should be careful not to do any damage. With
the exception that I should not turn her round before coming alongside,
the procedure would be the same as in the answer to the last question.
9. You are anchored in a river below a dock entrance on the flood tide.
Several other vessels are anchored astern of you. How would
you get into the dock?
Lift my anchor and drop up the river with the tide. Give my ship
a little way with the engines and sheer her-over towards the river bank
so that she will not foul any of the vessels astern. Avoid passing in
between them unless I had plenty of room. When clear of them all,
and above the dock entrance, steam slowly towards the pierhead, sheer
in gradually and lay her alongside the up-river knuckle. Enter the
dock as before.
304
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
10. Wliat would you do if there was not enough water for you to go round
outside them?
If I could pick a clear passage should lift my anchor, turn her round,
and steam slowly between them. If it was too risky to do that, it
would also be too risky to drop or dredge her up through them. That
being the case I should wait for slack water I could then get under
way and approach the entrance direct from the position where I was
at anchor.
11. What do you mean by “dropping” or “dredging” her up?
“Dropping” her up is done by lifting the anchor clear of the ground
and allowing her to drift up with the tide.
“Dredging” her up is done by leaving the anchor on the ground
but heaving the cable so short that the anchor will not hold. She then
drags or “dredges” it along the bottom.
Dropping or dredging her down is exactly the same thing, but, of
course, is done on the ebb tide.
12. Is the helm of any use when dropping or dredging a ship in a
tideway?
When “dropping” a vessel up or down she is simply drifting with
the tide and has no way through the water; the helm is consequently
of no use.
When “dredging” her the anchor retards her speed over the ground,
bringing her stem on to the tide and causing the water to pass by her.
The helm will then have the same effect and can be used in the same way
as if the vessel was going ahead.
13. Which knuckle do you work round when entering a dock!
The lee one, if the tide is not too strong.
14. How would yoii enter a dock, no tug and no steam on the main
engines?
Presuming my ship to be lying alongside in close proximity to the
entrance I should pass a good rope along from the inside quarter and
make it fast on the knuckle. Have a good check rope from the inside
bow. Spring the ship ahead with the quarter rope and when half her
length or a little more is past the knuckle head apply the check and
bring her head into the entrance. Heave her along into the lock.
DOCKING AND MOOBIND
15 You are coming up a river in a large steamer. How will you
alongside a wharf on your port side; you have the ebb tfejJ****
setting down on your starboard bow; no tugs ?
Steam up a little way ahead of my berth, keeping far enough out
to prevent the tide setting me heavily on to the wharf. Stop the engines.
Let go my off-shore anchor Get a line ashore from the port bow.
Slack away the cable and lay her gently alongside. If when coming
alongside she is inclined to bump her stem on the wharf, I should
remember that she will still answer the helm. Rudder to port
would tend to keep her stern off The rudder would be useful through¬
out the whole ]ob of berthing her. When safely alongside, slack the
cable down and make her well fast.
16 You are about to enter a lock. Stream across the entrance. The
ship will not answer her helm. What would you do?
Increase speed to get steerage way. Reduce again as soon as
possible. Come astern to check her if necessary.
Getting Under Way from Anchorage, Buoys, Wharves, etc.
17. What preparations would be necessary, and how would you get under
way, when lying at single anchor in an open roadstead?
Notify the engineers that steam for the main engines would be
required at a certain time. Have all hatches battened down, derricks
secured, and all deck fittings and gear prepared for sea. See that
steam was on the windlass and steering gear and that they were in
good working order. Put the helm over both ways. Test whistle
and engine room telegraphs, also other telegraphs and speaking tubes.
Have lead line handy and patent log ready fox streaming. Charts out
and sailing directions handy. Officers and crew at their proper stations.
All shore people ashore. Search for stowaways. If at night see that
my navigation lights and all other necessary lights were ready. Get
under way by heaving the anchor up.
18. You are riding to two anchors in an open roadstead in bad weather.
How would you get under way?
Steam slowly ahead towards my anchors and heave in some of thb
cable on both of them. Screw one of my cables up, say the port one.
Sheer her over towards my starboard anchor which will now be the lee
one, and heave it right up, stopping my engines when necessary, as the
306 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
starboard anchor is broken out she will drop back a little to the port
cable. Go easy ahead again to ease the strain on it and heave the port
anchor right up. See that the windlass is well screwed up and that all
is in good order forward as I proceed to sea.
19. You are in a river moored to a buoy with your cable. The tide is on
the flood. How would you get under way and proceed to sea?
Put a good slip rope on to the buoy and heave it tight. Reeve a
4-inch line through the ring on the buoy, bend it on to the chain and
heave on it to give the men a little slack Get the chain adrift from
the buoy, shackle it on to the anchor, and see it all clear for letting go
if necessary. Go slow ahead, take the slip rope in, and proceed down
the river.
20. You are moored to a buoy with your cable on the ebb tide How
would you get under way and proceed to sea?
Put a good slip rope on to the buoy, heave it tight, get the cable
adrift from the buoy and shackle it on to the anchor again, seeing all
clear as before. Let go my slip rope, turn her round with the engines.
21. How would you manage if there was not
enough room in the river to turn her
round with the engines?
Run a good wire out from aft on to the buoy,
heave it tight and make fast. Put a good slip
rope on to the buoy from the forecastle-head to
hold the ship for the time being. Unshackle
my cable and put it back on the anchor, seeing
it all clear for letting go if required. Sheer her
away from the wire and let go the slip rope
(Position 2). She will then swing round to the
wire with her head down the river. Let go
the wire from the buoy (Position 3), haul it in
and proceed (Fig. 4).
22. You are riding to your port anchor stem to
seaward in a narrow river at slack water.
How would you get under way and go
to sea?
Heave the anchor up, turn her round with
down the river.
the engines, steam
GETTING UNDER WAY
307
Another way would be to heave in some of the cable, go slowly ahead
passing the anchor on my port side with rudder to port and keeping
a little strain on the cable, steam slowly round the anchor until I was
heading down the river Stop the engines, lift the anchor, and proceed.
23 You are lying in a tideway moored to two anchors. How would yon
get under way?
Pay out on the cable ahead of me and drop back and pick up the
anchor I am not riding to. I could then steam ahead to ease the strain
on the cable and windlass and heave the other anchor up. I am then
“under way.”
24. How would you get under way when lying alongside a wharf head
down a river on the flood tide?
Keep a good backsprmg fast from my inside quarter, also a forward
breastrope. Take in all my other moorings. When ready, let go my
forward breastrope and haul it in The tide on my inside bow will
cant her head out. Go ahead on my engines, heave away on my after
backspring, finally lettmg it go and hauling it in (Fig 5)*
25. How would you get underway from a wharf when lying head to tide,
your ofl-shore anchor being down and bearing 2 or 3 points
on the bow?
Run a good headline out from my inside bow on to the wharf,
keep a good forward breastrope out and take in all my other moorings.
When all ready, let go my breastrope and haul it in. Ease away on
my headline and *et the ship swing out from the wharf and lie to the
anchor (Position 2, Fig. 6). Haul my headline in. Heave the anchor up*
308 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
26. You are moored port side to a whail on the flood tide which is coming
up under your stern How would you get away and proceed to
sea?
Leave my forward backsprmg out, also my after breastrope and
take in all my other moorings (Fig 7), the ship will then forge ahead
a little until held by the backsprmg. When ready, let go my breastrope
and haul it in, the tide on my inside (port) quarter will then throw her stern
out (Position 2). When well canted out, say at right angles to the
wharf, let go the backsprmg and come full astern on the engines (Position
3). Turn her short round, and proceed
27. What would you do if there was not enough room to turn her round
with the engines?
Let go my breastrope, and when she was well canted out as before,
let go the backspring and come astern clear of the wharf. Stop the
engines and let go my port anchor. She will then swing round to it
with her head down the river. Heave the anchor up and steam away.
28. You are moored starboard side to a wharf. How would you get away
when lying stem on to the tide ?
Keep a good backspring out from my inside bow, also an after
breastrope. Take in all my other moorings. When ready, let go my
breastrope and haul it in. The tide on my inside quarter will soon
cant her stem out. When canted far enough, come astern on my engines,
let go the backspring and heave it in.
DOCKING AND MOORING
309
29 How would you manage if your off-shore anchor was down bearing
about 3 points on the bow 2
Get away from the wharf in just the same way as before. When
canted far enough out, come full speed astern on the engines and heave
the anchor up at the same time If she swings right round and stems
the tide before the anchor is up no harm will he done.
30 Why not work your way along, and heave the anchor up before leaving
‘the wharf?
Because if I did so I might get my stern hard on the wharf as J
hove away on the cable Some damage might then be done to the ship
or to the wharf Cranes have been knocked over and other gear carried
aw T ay by attempting this method.
31 You are moored to a wharf with the tide astern ofyou. A vessel is lying
close ahead of you How would you get away?
Bun a good wire backspnng out from
my inside bow, carry it well aft along
the wharf, and drop the eye over a moor¬
ing post; heave it well tight and make
fast. Keep my after breastrope fast and
take m all my other moorings. When
ready, let go my breastrope and haul it m.
When her stern is canted well out come
full speed astern on the engines When
clear of the wharf, let go my backspring
and haul it in (Fig 8)
32 From what part of the ship would you pass out your wire backspring?
From my “shoulder pipe” or my “warping chock” on the forecastle-
head.
33. You are moored starboard side to a wharf, no tide, but the wind blow¬
ing directly across the river on to the wharf. How would you get
away?
If the wind were light I should run a good wire backspring out from
my inside bow, put it over a post well aft along the wharf, heave it well
tight and make it fast. Go slow ahead on my engines with the rudder
to starboard, and when the backspring has got the weight, increase
gradually to full speed if necessary. When her stem is canted out far
enough, rudder to port and come full speed astern on the engines.
Heave away on the backspring, finally letting it go and hauling it in.
310 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
II the wind were strong I should have to run a good line out to wind
ward to a buoy or dolphin to heave her head off the wharf Failing
this, a pull off with a tug would do. When her head was hove out
or canted out far enough, and everything was all clear, go ahead on the
engines.
A light ship having no outside assistance would have to remain
where she was until conditions were more favourable.
34. When a steamer is light and trimmed by the stern, would she steer
best with the wind on her port or on her starboard side, and for
what reason?
She would steer best with the wind on her port side. The side
thrust of the propeller tends to cant her head to port; the wind on the
port side has the opposite effect, and more or less counteracts it.
35. How would you bring a ship out of dock stern first, wind up the
river and not much room?
Come astern slowly through the locks, pass a quarter rope ashore
on the lee knuckle of the lock to check her close round the comer as she
comes astern, if there is not enough room to make a wider sweep into
the river.
MANAGEMENT OF STEAM VESSELS AT ANCHOR.
Obviously the ultimate aim is to minimise as much as possible the
danger of dragging: First, by keeping the anchor clear; and secondly,
when there is risk of the ship dragging her anchor, owing to strong
winds or tides or bad holding ground, to so manage the vessel that no
unnecessary strain may be imposed on the cable.
TENDING SHIP AT ANCHOR
311
Anchor buoys, although very useful for marking the position of
anchors, have fallen into disuse. This may be owing to the fact tnat
vessels do not as a rule stay long at single anchor; also, there is the
possibility in steamers of getting it foul of the propeller.
Effect of Long and Short Scopes of Cable.—The holding power of
an anchor varies with the amount of cable out. The shorter the scope
the more upwards is the pull of the ship on the anchor, and consequently
the less hold it will have. Vice tersa, the longer the scope the more
horizontal is the pull, and the better the anchor will hold, the best
position being attamed when enough cable is out to ensure the pull
being quite horizontal with some of the cable along the bottom. One
anchor with a sufficient scope for this purpose will hold better than two
anchors with an insufficient scope
A vessel anchored in deep water, with a proportionately long scope
of cable out, will ride easier in a sea, than when in shallow water under
the same circumstances, owing to the catenary* of the cable giving more
elasticity.
Veering Cable.—When it becomes necessary to veer cable in order
to give more scope, precautions should be taken for veering it slowly
and gradually. To veer away until slack, and then hold on, allowing
the vessel to tighten it suddenly, would be very likely to break the
anchor adrift. With respect to dragging, the saying “prevention
is better than cure” applies with special force. An extra length or
two of cable, given in time, may ensure the anchor holding, whereas,
if not given and the anchor starts, it may be impossible to get it to hold
again.
A ship at anchor will be influenced by one or both of two forces, i.e.
the tide acting on the immersed part of the hull, and the wind pressure
on the exposed parts of the hull, and on the spars, rigging, etc. In a
tideway the principal factor in the management of a vessel is the helm.
A “weather tide 99 is a tide setting to windward.
A “lee tide 99 is a tide setting to leeward.
Usually the effect of the tide on a vessel at anchor is greater than
that of the wind, though in strong winds, or weak tides, the reverse may
be the case, especially with vessels light or in ballast.
A vessel at anchor riding to the tide is moving through the water.
If riding to a 3 or 4-knot tide the vessel has the same relative
* A catenary is the curve which a chain or rope assumes when suspended
l>etwetn two points. The curve of a tow-rope when a ship is towed, also,
when a ship is at anchor, the curve of the cable between the hawsepipe and
the point where it rests on the bottom axe examples of catenaries.
3J2 KirilOLLS’s SEAMANSHIP AND NAUTICAL KNOWLEDGE
motion through the water as if she was being towed at the rate of 3
or & knots m still water It is sometimes helpful to look at the
subject m this light, and to regard the anchor as towing the ship through
the water.
Effect of the tide.—The effect of the tide is least when the ship
is stem on to it, and increases as she comes athwart, being greatest when
broadside on. The strain on the cable is, therefore, least when the ship
is stem on to the tide with the anchor right ahead To keep her thus,
however, would necessitate steering her as if under way, and under
ordinary circumstances where there is no likelihood of dragging, this is
not necessary or convenient because if left to herself with the helm amid¬
ships she would yaw about; it is best to give her a sheer to one side of
hex anchor with the helm, so that with the helm and cable together the
ship will be kept fairly steady.
When, however, the tide is strong and holding ground bad, and there
is any risk of dragging the anchor, only very little sheer should be given,
as the more sheer a vessel is given the greater is the tension put on the
cable. Under these conditions, therefore, in order that the ship may
be kept as steady as possible, it may be advisable to steer the ship as if
under way.
When a vessel is sheered to one side of the anchor, and the tide
coming on the wrong bow shoots her across to the other side of her anchor
she is said to “break hex sheer.” It must be borne in mind that it is not
a steady continuous strain which is most likely to start the anchor, but
the easing up and,sudden tightening, such as would occur if a vessel
broke her sheer, or if she is rising and falling in a heavy swell or sea.
Wind and tide.—The effect of strong winds on a vessel at anchor
may be considerable, especially if she is light. If the wind and tide are
ahead the effect of the two will be combined, and if there is a risk of
driving the precautions already stated should be taken.’
When the wind and tide are in opposite directions the ship is affected
by the difference of the forces, and by judicious management the strain
upon the cable may be considerably reduced. Suppose the ship to be
tide rode with the wind aft; the effect of the wind will be to ease the
strain upon the cable. Imagine now that the wind increases until
it has a greater effect than the tide; the ship then begins to forge ahead
towards her anchor. She must be steered clear of the anchor until
she is ahead of it, when the cable will bring her up again. Be careful
to keep her head on to the tide by meeting her with the helm, as though
the wind may be strong enough to drive her up against the tide when
TENDING SHIP AT ANCHOR
313
3 tem on to it if she gut athwart the tide it would, unless very w r eak,
have more effect on her than the wind and drive her back again,
probably folding or starting her anchor
Tending ship when moored.—A vessel when niooied does not occupy
so much room as when at single anchor, also, she cannot under ordinary
conditions foul either of her anchors She does not therefore require
tending in the manner that a ship does when at single anchor There
is, however, a great disadvantage in being moored should a strong
breeze spring up acioss the line of mooring, as the ship will be riding to
a span This is especially dangerous if the ship is moored taut It will
be well to illustrate this with a diagram.
A. Represents a ship riding to a span with an angle of 160° between the
cables The tension or force on each cable is three times as gteai as
would be put upon a single one ahead That is to say, an anchor and
cable ahead would have three times as much holding power as the
other two combined
B. Here the cables are supposed to be veered out so that the ship drops
from A to B, with an angle of 150° between the cables The tension
m this case on each one would be about twice as great as on a single
one ahead
C. The angle here is 120°, m which case the tension on each cable would
be just equal to that on one ahead.
Keeping a clear anchor.—The fact that the anchor when in use
is out of*sight frequently leads to its being ignored or neglected. Really,
it should have the opposite effect, for if fouled it constitutes a hidden
danger; and though the consequences may be no more serious than
to cause the extra work necessary to clearing it when getting under¬
way, it may render the anchor insecure or unsafe at the very time when
it is most required.
The fundamental principle of keeping a clear anchor when swinging
is to keep the vessel as far as possible from her anchor, or in other words,
to keep the cable as taut as possible. The weight of the cable itself is
considerable and must be taken into consideration. Under normal
M
314 :
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
conditions of wind and weather, it will, as the tide slackens, gradually
sink to the bottom, and by its weight hold the ship’s head to a certain
extent; hence it is necessary to sheer the ship mto a favourable position
for swinging before the tide is spent.
It is generally recommended to swing the ship on the same side of
her anchor at each turn of the tide if possible, in order to prevent
drawing the chain round the anchor. It is not always possible to do
this, as a shift of wind may render it impracticable. It does not follow
that, if she swings on different sides, the chain will foul the anchor, as
the anchor, under average conditions of wind and tide, would probably
slew in the ground at each turn of the tide. These remarks on tending
ship apply more to the old fashioned anchors rather than to the patent,
self-stowing, stockless type.
ANCHOR WORK.
1. Which is the working anchor in the Northern hemisphere, and for
what reason?
The port anchor. The reason is that if a vessel is riding to her
port anchor, and is afterwards obliged to let go the second one, when
the wind hauls and she swings round to it, the cables will lead clear of
each other and there will be no chance of getting a foul anchor.
Fig. 11.
In the Northern hemisphere the wind hauls to the right , shifts of wind
from S*W* to N.W. being common occurrence .
A vessel riding to heT port anchor (wind S.W.) may find it necessary
TENDING SHIP AT ANCHOR
315
on account of increasing wind to lot go her starboard anchor,
and to pay out on both cables. She will then have more cable out on her
port anchor than she has on her starboard one. (First position in left
hand diagram on p 314.)
When the wind hauls to the N.W. she should pay out more starboard
chain, and will swing round with her cables all clear and the anchors in a
good position each a little on their own bow. (Second position in left
hand diagram on p. 314.)
If she were riding to her starboard anchor and then had to let go the
port one, she would have less cable out on the port anchor than she
had on the starboard one. (First position in right hand diagram on
p. 314).
As the wind hauled and she swung round to it, she might drag her
starboard cable foul of the port anchor. Even if she did not do so,
the port anchor would be on the starboard bow, and the starboard
anchor on the port bow with the cables crossing. (Second position in
right hand diagram on p 314.)
2. Which anchor would you use when bringing up in the Southern
hemisphere; and for what reason?
The starboard one. In the Southern hemisphere the wind hauls
to the left, and if I brought up with my port anchor and later on had
to let go the starboard one, I should have a cross in my cables when she
swung round as the wind shifted. I might also drag my port cable
foul of my starboard anchor.
To keep my cables clear, whatever I did with my port anchor in the
Northern hemisphere I should do with my starboard'anchor in the
Southern hemisphere.
3. You are at anchor riding lee tide, what would you do if you found
that she was dragging?
If I thought that she would hold by giving her more cable, I should
do so at once. If not, I should give her a sheer and let go the second
anchor, paying out on both cables.
4. You are lying at single anchor in a tideway. How would you prevent
the cable fouling the anchor at slack water?
Give her a good sheer from her anchor just before slack water.
This will draw the chain clear, and she will turn the anchor round in the
ground as she swings to the new tide-
316 NICH0LL8*8 SEYMANSHIP AND NAUTICAL KNOWLEDGE
5. You are riding weather tide m a strong breeze, where will vour an/?ir>r
be lying?
If the wind has more effect on the ship than the tide has, she will
forge ahead of her anchor and probably he partly athwart the tide.
The anchor will then be on the quarter and remain there as long as the
wind is strong enough to keep the ship in that position.
If the wind moderates so that the tide has the greater effect, she will
drop back again, and the anchor will he ahead.
6. Where would the anchor be if you were riding lee tide?
Ahead, unless I gave her a small sheer from it, in which case it
would be a little on the bow.
7. How would you heave your anchor up if your hawsepipe was badly
damaged?
Hang a kedge anchor over the bow in a suitable position, lash
it securely with chain, and let the cable come m over one of the arms.
8. You are riding to a strong tide with a shoal on your quarter; how would
you sheer your vessel?
I would sheer her towards the shoal so that, in the event of the ship
breaking her sheer and starting the anchor, she would go away from it.
Also, the anchor, when the ship was sheered towards the shoal, would
probably be pulling towards rising ground and hold better.
9. You arc anchored astern of another vessel in a tidal river. What
would you do if you found that she was dragging her anchor and
driving towards you?
Veer away as long a scope as possible on the cable and try to get
clear of her by giving my ship a broad sheer. Should screw the windlass
up with a shackle just abaft it ready for slipping, if necessary. Buoy
the cable. Have good fenders handy.
10. You have managed to clear her, but she has fouled your cable with her
anchor. What would you do?
Slip it, and bring up with my other anchor. If I had steam I should
have no difficulty in picking out another berth, or steaming away clear
if the river was overcrowded with shipping. If no steam, should have
to be specially careful not to get athwart of any other vessel or go ashore.
11. What would you do if the positions were reversed, and you were
driving down towards another vessel?
Let go my second anchor. Use my engines if I had any steam. If
TENDING SHIP JLT ANCHOR
317
J continued to drag 1 might clear her by giving my ship a broad sheer.
Should signal to her to sheer the opposite way if she was not already
doing ao.
12. What special precautions would you take if you were obliged to
anchor in a river where the holding ground was known to be bad?
Should keep steam up, and if necessary, ease the strain on the
cable by going slow ahead on the engines. Have proper watches kept
so that I was ready to get under way at any time.
13. What would you consider your special duty as regards anchors,
cables, etc., if you were mate of a ship?
Make myself thoroughly acquainted with the working of the windlass
under all conditions. See that the pins were not rusted up in the
shackles of the cables so that they could be quickly slipped, and that
buoys with good buoy ropes were kept handy. Have my spare bower
anchor stowed where it could be easily got over if necessary. Overhaul
my stream chain and see that the shackles belonging to it were in good
working order, and that it was stowed handy and ready for use.
14. What is the difference between riding to two anchors and being
moored to two anchors?
A vessel is said to be riding to two anchors when they are both ahead
of her, such as is the case when she has had co let go a second anchor to
hold her in bad weather.
She is said to be moored when she has one anchor ahead and the
other leading stem to hold her in one position.
15. What advantage is there in being moored to two anchors as
compared with riding to one anchor?
The ship covers much less ground in swinging. By riding to the
flood on one anchor, and the ebb on the other one, she turns round
practically in her own length.
When riding to a single anchor she swings from flood to ebb or ebb
to flood on the full length of her chain, and, except with stockless
anchors, there is also the possibility of the chain getting under the stock
and making a foul anchor unless carefully tended.
16. What is the disadvantage of being moored to two anchors?
The fact that should bad weather come on, my second anchor
being down astern of me, it is of no use in helping to hold the ship.
318 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
17. You are moored in a roadstead, one anchor to hold her on the ebb
tide and the other on the flood. A gale springs up from abeam
so that she swings to it with the cables across the stem. What
action would you take?
Slack away gently on both cables so as to bring the lead of the
cables more ahead. Pay out with due regard to the depth of water
I shall have astern at low water. When the gale dies away heave them
both in again.
18. You are moored in a river riding to the starboard anchor. A gale
springs up from ahead and the ship begins to drag. What would
you do?
Pay out gently on the riding cable, heaving in the slack of the other.
As long as the ship kept on dragging I should continue to pay out on
the starboard cable. After passing l^he port anchor I should get a strain
gradually on the port cable. The two anchors should then hold her.
19. Lying at single anchor, your ship is sheering about heavily. What
would you do to steady her?
If there was any tide I should send a hand to the wheel to steer her.
By tending her carefully the sheering could be prevented.
If no tide, she might be steadied by setting fore-and-aft sails with
their sheets amidships. These would help to keep her on one side of
her anchor.
If sails proved to be useless I should wait until she sheered the right
way bringing the anchor well out on its own bow, then let go the other
anchor and pay out cable on it.
*
20. You are lying at single anchor with a gale expected. What
precautions would you take?
Heave in some of the cable to which I was riding, give the ship a
sheer from her anchor, let go the second anchor and pay out on both
cables.
21. You are in a vessel moored in a river. She sheers towards the bank
on her port side. What would you do?
While the tide was strong enough she could be. kept in position by
a hand at the wheel to tend her if necessary. If I had steam I should
make use of the engines.
ANCHORING AND MOORING
319
22. How would vou keep a clear hawse when your vessel is moored?
Just before the finish of every tide I should give her a cant with the
helm so that the new tide will always swing her round on the same
side of both her anchors, i.e on the same side of an imaginary straight
line joining the two anchors.
When a vessel is properly moored where there is room to swing
either way, a clear hawse can always be kept by canting her head to
port before the turn of the tide when she is riding to her starboard
anchor, and to starboard when she is riding to her port anchor.
23. You are moored near the bank in a tidal river. How would you
tend her and keep a clear hawse?
When the tide is finishing give her a sheer with the helm, canting
her stern out from the bank in the deeper water. The new tide will
then catch her on the quarter and swing her round the right way. I
should do this every time the tide changes. As long as she swings on
the same side of both her anchors at every turn of the tide she will
always keep a clear hawse.
ANCHORING, MOORING, Etc.
Use a small model when studying this subject.
24. How would you bring a steamer to anchor in an open roadstead
at slack water?
Slacken speed as I approach the anchorage, and stop the engines
when necessary. Have both my anchors ready, and see that everything
is clear of the cables and windlass. If there is a strong wind, round her
head up towards it. When in the berth I wish to take up, give her a
little sternway with the engines, and let go the anchor.
25. How much cable would you give her?
That will depend on the depth of water, the weather conditions at
the time, and the quality of the bottom. In fine weather and with
good holding ground, five times the depth of water should be enough.
26. How would you bring up with two anchors in an open roadstead in
bad weather?
Slacken speed, round her to, and before she comes head to wind
let go my weather anchor and pay out cable. Sheer away from it,
stop my engines, and when she has lost headway and begins to drop
back let go the other anchor. Pay out plenty of cable on both anchors,
320 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
use my engines to ease the strain on the windlass when brineng
her up.
27. You are proceeding up a river on the ebb tide; how would you 'Vfrme
to an anchor?
Ease down the engines as I come to my berth, and stop them at
the proper time. As soon as the tide begins to take her astern over the
ground, let go the anchor
28 You are going up a river on the flood tide, how would you come
to an anchor?.
Round her to and stem the tide. Ease her down and stop the
engines. As soon as she begins to go astern over the ground let go the
anchor.
29 You are coming up a river on the flood. How would you make fast
to a mooring buoy with your cable?
Hang one anchor off, unshackle the cable and have it all ready
in good time. Steam up past the buoy, round her to and stem the
tide. Come ahead easy up to the buoy and put a good slip rope or
wire pn to it to hold her with. Reeve a 4-inch rope through the ring,
bring the end back on board and make it fast to the cable about a
couple of links from the end. Heave it out and shackle on.
If no shore assistance and I had to use my own boat should lower
it into the water before I passed the buoy. They could then drop up
to the buoy*with the tide.
30. How would you moor her head and stem between two buoys , same
flood tide?
Come up the river till above both the buoys, round her to and
stem the tide. Steam slowly (against the tide) past the buoy for my
stem moorings, and make well fast to the buoy ahead. Should shackle
my cable on to it or use good wires.
Having finished forward, run a line out to the after buoy and get
my stem moorings on to it. Make them well fast.
31. How would you moor her in between the same two buoys if you had
arrived there with the ebb tide coming in ?
Steam slowly up past the first buoy which I shall use fox my stem
moorings, use my engines as required and make her well fast to the
buoy ahead. Get my stern moorings out afterwards.
anchoring and mooring
321
32 You coming up a river on the flood, how would you make an
ordinary moor? You want 60 fathoms on the port anchor and
45 on the starboard one.
Round her to and stem the tide. Steam slowly up into the right
position, stop the engines, and as soon as she goes astern over the
ground let go the port anchor. Slack away freely at first, gradually
checking her until 1 had 105 fathoms out, when the ship being held by
the port anchor I should let go the starboard one. Pay out to 45 on the
starboard anchor and heave in 45 on the port one. Should use the
engines to ease the strain on the cable as I hove in.
33. How would you make a running moor under the same conditions?
Round her to and stem the tide. Work her into the right position
and let go my port anchor while steaming slowly up against the tide.
Stop the engines when necessary, slacking away on the cable until
I had 105 fathoms out. The ship should then be stationary over the
ground with the port anchor astern of her and the cable in a straight
line along the bottom As soon as she begins to drop back with the
tide, let go the starboard anchor, pay out gently to 45 fathoms, at
the same time heaving in 45 on the port one.
34. How would you make a running moor with the tide finishing up with
60 fathoms on the port anchor and 45 on the starboard one?
Come up very slowly. Have no more than steerage way on my
ship, stop my engines as I approach my berth, the tide will take her
up over the ground. When in the right position let go the port anchor
paying the cable out freely at first, but gradually checking her until I
had 105 fathoms out and she had swung round slowly to port and was
stemming the tide. I should then let go the starboard anchor and pay
out to 45 fathoms, at the same time ‘heaving in 45 on the port one.
Ease the strain by going slow ahead on the engines as I hove in.
35. What would you do if the cable parted while you were making this
running moor, the ship having got nearly athwart the tide at
the time?
Heave in the slack chain that was left (if any) and straighten her
up to stem the tide as soon as possible, taking care not to get foul
of anything that might be about. I could then let go my other anchor
and ride to that for the time being. Should get my spare bower shackled
on to the remaining cable so that it was all ready for use until I was
abie to recover the other anchor.
322 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
36. What would happen if other vessels were anchored so near that you
had not enough room to round her to before bringing up?
I should use my engines and steam away clear of them. Whether
I went ahead or came full speed astern would depend on the positions
of the other vessels, the depth of water, my distance from the river
bank, etc.
If not able to do this, I should drop my starboard anchor immediately
and snub her round with it. The cable would be across the stem
until she swung round, blit that could not be avoided in this special
case of emergency. Should ease the strain on the cable by going
ahead on the engines as soon as practicable.
37. Would you prefer to make a running moor with the tide or against
the tide, and for what reason?
I should prefer to make it against the tide. The reason is that
there is not so much risk involved by stemming the tide and steaming
up against it, as there is by dropping the anchor while going with the
tide and swinging her round to it. Too much strain may be brought
on the cable and windlass by the latter method, even though the ship
may have been going very slowly.
38. When mooring a ship, why do you sometimes give her more cable
on one anchor than on the other?
Because in many places the tide runs stronger in one direction
than it does in the other, and more cable is required on that anchor
which will have to hold the ship against the stronger tide.
Prevailing winds blowing with the flood would make it necessary
to give her more cable on the anchor holding her to the flood tide; if
they blew with the ebb, she would want more on the anchor holding
her when riding to the ebb.
SENIOR OFFICER’S WORK.
ACCIDENTS.
The internal organisation and appliances on board ship are designed
to enable the routine work to be carried out smoothly and without
accident, but “to err is human” and materials may fail at a critical
period. It is the duty of responsible officers to anticipate sudden
emergency calls and to think out in advance what should be done -in
the event of various contingencies arising. Circumstances alter cases
PRECAUTIONS IN HEAVY WEATHER
323
and accidents come unexpectedly; they catch us unawares and not
always under the ideal conditions of an examination room.
The foliowmg hypothetical questions and answers may offer guidance
and inspiration
1. Your steering gear carries away. What would you do?
Stop the engines Steady the rudder by bringing the brake into
action on the quadrant. Put up the “not under command 3 ’ signal.
Repair the damage.
If one of the chains had parted, say the starboard one, the rudder
could be put hard to port to haul the port chain tight, the rudder would,
of course, have to be clamped in that position by the brake. The strain
on the chain would then assist the brake in keeping the rudder quiet
whilst the repairs were in progress. When finished, unclamp the brake
off the quadrant, go ahead on the engines and take down the “not
under command” signal.
I could connect up my hand steering gear and use that temporarily.
Most ships are also fitted with heavy steering tackles and suitable
leads for them to be used in case of emergency.
2. Your steamer in heavy weather takes a big sea over the forecastle-
head which damages No. 1 hatch. What would you do?
Ease her down. If necessary heave her to. Repair the damage.
Inform the engineers before heaving to so that they may ease the steam
pressure accordingly.
3. How would you heave her to?
By bringing her head slowly in to the direction in which you find
she lies easiest and makes the best weather of it. That would probably
be with the sea a little on either bow. Keep the engines turning just
fast enough to maintain her head in that direction. Fore-and-aft
sails may be useful for steadying purposes.
4. How would you heave her to if you were running before a heavy sea?
Have everything well secured about the deck and see that the
crew are clear out of the way. Ease the engines down. Watch for a
smooth and at the first good chance put rudder to port and let her
come to. gently. Spread oil freely from the weather bow as she comes
up towards the wind. 1
In the case of heaving to in a gale of wind and heavy sea it is not
only the weather conditions which have to be considered. Much
324
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
must depend on tlie ship herself and the state of her trim, dome ships
lie very well when they are kept before the sea with their engines going
slowly ahead.
5. You are running before a heavy gale and the ship is labouring badly.
What could you do to relieve her?
Reduce the speed to that at which she makes the best weather
of it, having regard to the fact that the faster I can keep her going the
less likely she is to take heavy seas over the stem Spread oil judiciously.
I might alter the course so that she will take the sea more kindly.
6. When heaving to in a steamer would you prefer to carry the wind
on the port side or the starboard side ? State the reason.
I should prefer to carry the wind on the port side. With engines
going ahead and the ship having a right handed propeller, the tendency
of the side thrust is to cant her head to port. She would therefore lie
up better with the wind on the port bow than she would with it on the
other side.
7. What makes a vessel roll?
The waves or the swell. The magnitude of the rolling depends
upon the state of the vessel’s stability as well as on the amount of sea
which is running. A “stiff” ship will roll more violently than a
“tender” one.
8. Your ship is rolling heavily. What can you do to steady her?
An alteration of course would be the alternative. I should keep
her going in the direction (as near to my proper course as possible)
in which she made the best weather of it. Should steam at a reduced
speed if I did not like the track she was making. Should heave to if
necessary.
It would be very dangerous to do anything in the way of emptying
or filling ballast tanks while the ship was rolling heavily. The rush
of water in a partly filled tank might damage the crown of the tank
which would then let water into the hold. If the tank was being <f run
up” the result might be very serious before the damage was discovered.
9. Your funnel gcfes over the side. What would happen and what
would you do?
The decks would be enveloped in smoke, heat and clinkers would be
troublesome, and the draught through the furnaces would be very
much reduced.
EMERGENCIES
325
I should rig up a jury funnel. Possibly the engineers could make a
cylinder from some spare ventilators and other stores on hand. This
could be erected on the funnel coamings. If not long enough, a wooden
shaft lined with sheet metal and covered with canvas could be added
to it. Plenty of guys would be required to steady it. The hose should
be played on it frequently to prevent it being quickly scorched through.
This would increase the draught and carry the smoke up clear of the
deck. It would want a lot of attention and probably would not last
very long.
10. You have a strong wind on the starboard quarter. A man falls
overboard. What would you do?
Heave him a life-buoy. Stop the engines. Rudder hard over to the
side he fell off; start engines again and steam right round to windward
of^the man under easy revolutions Have the emergency boat cleared
away and manned with a suitable crew. When in a good position
heave to and lower away the boat, spreading oil for a smooth. While
they are picking the man up, manoeuvre the ship into position to make
a lee for the boat, agam spreading oil before she comes alongside.
See that the boatrope is ready with hands to tend it. Hook on and
hoist her up as quickly as possible
11. Your vessel has taken the ground at low water and her bottom in the
way of No. 1 hold has been pierced by the anchor. What
would you do
When the tide makes again she will float on her tank tops. Take
her into dry dock. Call a survey. Have the damage repaired. Get
certificate of seaworthiness.
If no dry dock or patent slip is available I should take safety pre¬
cautions by stiffening my tank tops, carrying out surveyor’s require¬
ments. Should then obtain permission to proceed to the nearest
port where permanent repairs could be done. This would be granted
by the surveyor when he was satisfied that the ship was seaworthy.
Get certificate of seaworthiness in duplicate. Send one copy to my
’ owners.
12. You are passing to windward of a sandbank in a strong wind. The
tide is setting on to the bank. Your engines break down.
What would you do?
Get to windward all I can while I have any way left over the ground.
Bring up at once using both anchors if necessary. Give hex plenty of
cable on both of them. Get the damage repaired as soon as possible.
326 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
13. You are coming up a narrow river on the flood tide. How would
you turn her round?
Stop the engines in good time and sheer her gently m towards
the bank on my starboard side. When far enough ahead come full
astern on the engines and drop the starboard anchor under foot. Her
stern will swing round up river with the tide. Lift the anchor, rudder
to starboard, go ahead on the engines. Straighten her up.
14. Suppose you were in the North Sea and your rudder got disabled.
What would you do?
Come to an anchor. Use my best resources to repair the damage.
If impossible to get the rudder working properly I should try to steer her
by towing something astern and running the towrope across from
quarter to quarter. This could be done by means of a gin running along
a wire stretched round the stern for that purpose. This might enable
me to reach port. Should send a wireless message in code to my
owners, explaining the circumstances fully and giving the position of
the ship. Assistance could then be sent if required.
If my ship had twin screws I could run one at a regular speed (not
full speed) and steer the ship by increasing or decreasing the revolutions
on the other.
15. Your rudder plate is damaged. You are in dry dock. How would
you unship the rudder for repairs?
I should unship only the lower part. It would not be necessary to
disturb the quadrant or rudder head.
Big two good three-fold purchases over the counter, one on each
side. These can be suspended from the after bitts.
Put the helm hard over, it does not matter which way.
Secure the lower purchase blocks to the upper part of the rudder
plate by means of shackles, or lash them with a good chain lashing
round the rudder spindle underneath the flanges of the coupling.
Take a strain on both purchases and make them fast.
Disconnect the rudder coupling by taking the bolts out of the
flanges. Then put the helm hard over the other way so that the two
flanges become clear of each other, and the lower part of the rudder
can be lifted up.
Disconnect the locking pintle.
Have a screw or hydraulic jack in the dry dock underneath the
bottom of the rudder. Raise the rudder with jack, heaving away on
EMERGENCIES
327
the purchases at the same time until the pintles are clear of the gudgeons.
Remove the jack. Guy the bottom of the rudder clear and lower away.
16. How would you manage if you had to do the same job with the
ship afloat?
Rig the two three-fold purchases and secure them to the rudder
in the manner just described. Disconnect the rudder coupling and
locking pintle.
Raise the quadrant and rudder stock high enough to get the lower
part of the rudder clear. This could be done with a jack on deck
underneath the quadrant or by means of wedges between deck and
quadrant.
Heave away on both tackles until the pintles are clear of the gudgeons.
The rudder will then be free of the rudder post.
Slack away on one tackle until the rudder is hanging by the other.
Heave it up and land it on a barge. If alongside a wharf
or in dock I could dispense with the barge by gettmg a crane on to the
rudder and lifting it ashore direct from my tackle.
17. How would you unship an old-fashioned rudder? The spinclle and
stock are in one piece.
When dry docking the ship inform the dockmaster that I want her
settled down on the blocks with her rudder over the rudder pit in the
bottom of the dock. This to enable me to lower the rudder down
far enough to get the head out of the rudder trunk.
Clear away the rudder head by removing the key and taking off
the crosshead and quadrant. Clear out the stuffing box. Remove
the collar plate from around the bottom of the rudder trunk, also the
locking plate from the rudder. Tap a hole 1 inch in diameter vertically
in the rudder head. Screw into it a stout eye-bolt for lifting purposes.
Rig a pair of short stout sheerlegs over the rudder head, seemg that
the deck is shored up underneath them. Hang a good threefold purchase
from them. Use iron blocks and a wire fall. The lower block must be
small enough to go down through the rudder trunk. Shackle it on to
the eye-bolt which you have screwed into the rudder head. Take the
weight of the rudder in the purchase, a jack under the bottom of the
rudder will help to lift it enough to get the pintles out clear of the
gudgeons. Make the fall of the tackle well fast and remove the jack.
Open up the pit in the dry dock underneath the rudder post and lower
the rudder down into it. Remove with another tackle or the dock crane*
328
NICHOLLS^S SEAMANSHIP AND NAUTICAL KNOWLEDGE
If I had to unship the rudder while the vessel was afloat the pro¬
cedure would be the same except for two things. I should not be able
to have a jack underneath the rudder to assist my purchase when
heaving up; also, when the rudder head was lowered down clear of the
trunk I should have to get another purchase on to it to lift the rudder
up into a barge, or possibly on to the dock wall if alongside.
18. How would you unship a propeller?
With two tackles hung over the quarter, one on each side. They
should be three-fold purchases, and either wire or manila may be used
for the falls. Sling the propeller round the boss with good chain, and
shackle the lower blocks of both purchases on to it. Take the weight,
putting an equal strain on both tackles. Unscrew the lock nut. Re¬
move the key. Start the propeller by means of steel wedges. In
some yards hydraulic power is used. Disconnect an intermediate
length of shafting. Draw in the tail shaft. Slack away on one
tackle. The propeller will then swing out clear of the stem frame,
the whole of the weight gradually coming on to the other tackle. Land
it on some heavy planks or on to a trolley if it is to be moved away.
19 Your windlass is broken down. How would you heave up your
anchor?
With a tackle. Reeve ofl a good three-fold purchase. Take the
block having the hauling and standing part of the rope in it and shackle
it on to the cable close abaft the hawsepipe. Overhaul the purchase
to a good long drift and make as fair and clear a lead as possible. Attach
the other block to some secure object such as a pair of bitts or a side
bunker hatch. Do all that can be done to avoid chafe.
Take the fall to a fore deck winch and heave away. Use the engines
to ease the strain on the purchase. It will be necessary to stopper the
cable oil and fleet the purchase from time to time. Heave the anchor
right up into the pipe and secure it.
If unable to get the anchor away by this means, make the cable
well fast and break the anchor out by going ahead on the engines.
20. Your kedge anchor is foul. How would' you recover it?
Get two motor boats away and sweep for it with a bight of wire.
Having got the anchor in the bight, bring the two parts of the wire
together, place a large shackle round them and let it run down on to
the anchor. Heave away on both parts of the wire.
ACCIDENTS
329
21. One of your bower anchors is damaged. How could you replace it
with the spare one ?
Lower the damaged one down until it is just clear of the hawse
pipe. If no crane on the forecastle-head I should use No. 1 derrick
and winch for handling it. Overhaul the wire along outside clear
of everything and shackle it on to the ring Have steam on the windlass.
Heave away on the wire (see the derrick is properly guyed) and walk
back the windlass. Light up the weight of the cable if necessary.
Get the anchor in on the foredeck or forecastle-head. Put a lashing
on the cable to prevent the end running away. Unshackle it from the
damaged anchor and put it on to the spare bower. Shift your derrick
wire on to the spare bower. Come up the clamps and lashings securing
it on its bed. Don’t forget the lashing on the cable.
Take the weight on the derrick and guy it out to the side as required.
Come back gently on the winch and heave the cable slowly m with the
windlass until the anchor is under the hawsepipe. Unshackle the
derrick wire, heave the anchor up into the pipe and secure it.
If the combined weight of the anchor and cable is too much for the
wire, I should hang a block at the derrick head and reeve off a purchase
which would be suitable for the job. A wire pendant might come in
useful if the drift was a long one; or:—
Lift the damaged anchor on to the deck without the cable. Hang
the anchor off under the hawsepipe and unshackle the cable. Reeve
a good wire out through the hawsepipe to take the place of the cable.
Lead it to a winch. Take the weight of the anchor on your derrick
and hawsepipe wires. Cast adrift the lashing with which you hung
off the anchor. Slack away your hawsepipe wire and heave the anchor
up on to the deck with the derrick wire.
Get the spare bower down under the hawsepipe with the same two
wires. Shackle the cable on. Get the wires adrift from the anchor.
Heave it up into the pipe and secure it.
22. You come across a steamer which has lost her rudder. How would
you assist her into port?
Manoeuvre into a position astern of her. Take two good wire
hawsers, one from each of her quarters, and make them securely fast
on my forecastle-head. Shackle them on to my cables if I expected
bad weather so that there shall be some spring in them
Let her go ahead of me, making the best speed she can under the
330 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
circumstances, when I should steei her by following astern and keeping
a little strain on the wires.
23. Your engines have broken down in heavy weather. What would
you do?
Keep the ship out of the trough of the sea as much as possible while
the engme-Toom staff get on with the repairs. If the water is not too
deep, unshackle the cable from one or both of the anchors, pay out a
long scope and let it drag along the bottom. Fore-and-aft sail might
also help to steady her. Spread oil to windward. If the water was
too deep for the cables to keep her head up, should do the best I could
with a sea anchor. Hoist the “Not under command” signal.
24. Your ship has a right-handed propeller. How would you turn her
short round with her head to port?
Let go the port anchor under foot. Go slow ahead on the engines
with the ludder to port. When turned sufficiently heave the anchor
up again and proceed.
25. You are bound to the Bristol Channel in ballast from the Continent.
Heavy westerly gales are blowing. How would you make
westing down towards Land’s End?
Proceed down Channel with the ebb tide, and if possible anchor
against the flood. Take every possible advantage of changes in wind
and weather. Get in a good position to bring up each time the tide
turned against me. If I could not do any good against it, should run
in for shelter. The Downs, under the lee of the Isle of Wight, Wey¬
mouth Bay, Portland Roads, Tor Bay, Falmouth and Mount Bay all
offer good shelter in westerly gales.
26. You are anchored ahead of some vessels riding to the flood tide. Port
anchor down. No steam on the main engines. How would
you get her up the river and enter a dock on your starboard
hand?
I should dredge her up the river with the tide, passing in between
the river bank and the vessels astern. Heave in cable until the anchor
is nearly under foot and she will drag it along over the bottom. Wheel
to starboard to shear ship to starboard clear of the vessels astern and
dredge laterally and stem first up the river. When far enough across
to clear the vessels at anchor, straighten her up by easing the helm
and dredge her stem first up the river, closing in towards the dock
ACCIDENTS
331
entrance. Ease her alongside the up river knuckle. Make her well
fast and heave the anchor home.
Bun a line from the starboard quarter well ahead on to the knuckle,
also one from the starboard bow to be used as a check rope when
required. This would be carried along the entrance to the lock by the
pierhead men. Spring the vessel ahead with the quarter rope until
she is half way past the knuckle and then apply the bow check and
swing her head round into the dock entrance.
If there was any flood tide left I could help to get her round the
knuckle by running a line from my port quarter on to the down river
knuckle and taking it to the winch.
27. You are coming up a river on the flood tide Turn short round,
makmg use of the tide.
If the river is fairly straight, the strongest part of the stream is
generally in mid-river That being the case I should slow down, sheer
in towards the bank on my starboard side to bring my bow into the
slacker water, and when far enough in come full speed astern with helm
amidships. The strong flood in mid-river will catch her on the star¬
board quarter and swing her stem round up river, when far enough,
rudder to starboard and full speed ahead to straighten her up. Repeat
if necessary.
HOW TO RIG A SEA ANCHOR AND USE IT FOR KEEPING
A VESSEL OUT OF THE TROUGH OF
THE SEA, Etc.
The best practical sea anchor for use in moderate depths of water
is made by unshackling one of the bower anchors and paying out a
good length of the cable only. This will drag along the bottom and
keep the ship’s head up towards the wind and prevent her lying in the
trough of the sea. It is easy to rig as it only necessitates the hanging
off of one anchor, and it is more efficient than any floating object could be.
For use in deep water, a sea anchor could be made as follows:—
Get a spar such as a wooden derrick or good boat spar, and lash the
luff of a staysail or trysail along it. Secure a piece of chain or other
weight at the clew. This weight must be heavy enough to make the
sail hang vertically underneath the spar in the water but not so heavy
that it will sink the spar. Rig a bridle with a good piece of rope attached
to each end of the spar, and make the end of a hawser fast to the middle
332
NiCHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
of the bridle. Put it out over the bow and pay out a good drift on the
hawser.
Three spars lashed together m the form of an equilateral triangle
and covered with stout canvas would also answer the purpose. In this
case a three-legged bridle would have to be used and one corner weighted
as before.
Two spars lashed together in the form of a cross with a cham stretched
from arm to arm to form the outline would also do, but would require
a double bridle (four-legged); this would also have to be covered with
canvas and weighted at one comer to keep it vertical in the water.
The two last mentioned have the disadvantage of being heavy,
troublesome to make, and very awkward to handle.
A few large cargo baskets paid out on a long line would be easy to
rig and might prove good enough.
Any floating object that will offer reasonable resistance to the drift
of the ship will make a more or less efficient sea anchor.
An oil bag hauled out to the sea anchor by means of a block and
small line would be beneficial in very bad weather.
Heaving a Vessel off When Aground.
1. What would you do if your vessel ran aground, no tugs or shoje
assistance being available?
Sound the wells, and if she was not leaking do my best to get her
off again at the next high water.
If she was badly holed I should make sure that it was safe to get
her off into deep water before attempting to do so. If possible, I should
try to make a temporary stoppage of leaks before floating her, and in
the meantime run my spare bower and another bower anchor out ahead,
or take some other action to prevent her slipping of before I was
ready. Should also make quite sure that my pumps were able to deal
with any leakage that might remain or be likely to develop.
2. If you decided to get her off, how would you do it?
Take careful soundings to find out where the best water was, and
try to get her off at the next high water by using my engines and ballast
tanks to the best advantage. If practicable, shifting cargo might
help me. Should consider the possibility of discharging some cargo to
lighten her forward, but should not jettison cargo unless it became a
matter of extreme urgency.
STRANDING 333
3. Suppose you could not get her off by this means, what would
happen 2
1 should carry out my spare bower anchor, also one of my other
bower anchors if necessary, and try to heave her off with them, of course,
also using my engines and ballast tanks.
4. Are you running any particular risk by using your engines in this
case?
There is the possibility in the shallow water of mud or sand or
weed being drawn into the condenser tubes and thus temporarilv
disabling the engines. If I had two inlet pipes leading to the condenser
should use the upper one as being less likely to get choked. Should
also protect the inlet valve with a wire guard or some other arrangement
if possible.
5. How would you carry a bower anchor out?
Between two boats. Lay a kedge and guess warp out in a position
suitable for heaving out the boats carrying the bower anchor.
Shackle a good wire on to the spare bower, and lower it over the
side with one of the forward derricks until the shackle is 3 feet or so
above the water level. Bring the two boats along one on each side of it.
Make a good spar well fast across the four gunwales about the middle
of their length. Lash the shackle of the anchor to the spar making
sure that the wire will be underneath the spar when the anchor is dropped.
Ease the weight gradually from the derrick on to the spar and unhook
or unshackle the anchor from the derrick.
Heave the boats out with the guess warp, paying the wire out from
on board the ship. When in the right position cut the lashing and
let go the anchor. Heave the boats back with a line also paid out
from the ship as the boats went away. If the kedge was not required
any more, pick it up and bring it back with me.
6. If the anchor was an old-fashioned one with a stock, would you
carry it out in the same way?
Yes. I should, however, have the boats far enough apart to give
clearance to the stock or be careful to hang the anchor low enough
for the* stock to be below the keels of the boats on account of possible
damage if it swung round.
334
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
7. How would you manage if there was not enough water near the ship
for you to hang it vertically?
Hang it horizontally between two spars. I should sling it carefully
with the arms vertical and stock in a horizontal position, and lower it
down to a suitable level, first shackling the wire hawser on to it Bring*
the boats along, one on each side of it, and lash two spars across the four
gunwales, one to take each end of the anchor. Secure the upper fluke
to one of the spars by means of a rope that could be gently eased away,
and la*sh the ring to the other one. Heave the boats out with the guess
warp as before. When in the right position, cockbill the anchor, that
is, allow it to hang vertically by slacking away and then lettmg go the
fluke lashing. Let go the anchor by cutting the ring lashing. See
that the wire is all clear before letting go.
JURY STEERING GEAR.
In the event of the steam steering gear breaking down, the hand
or emergency gear must be connected up, but should both carry away
then ways and means of rigging a working attachment to the quadrant
or tiller must be devised. The following efficient system of block and
tackle gear was rigged up in the American steamer West Harshaw
JURY STEERING GEAR
335
while on a voyage from Galveston to Liverpool when the worm steering
gear frame broke down in heavy weather, totally disabling both steam
and hand gear. Wire tackles were attached to the tiller. Manila
luff tackles were secured to the wire and led to the winch, turns being
taken in opposite directions around the drumheads. Lead blocks were
secured J abaft each, with the ends of the luff tackle falls rove through
them and bent together, making an endless purchase as shown in Figure
12. The tension tackle was used to take up the slack. The ship was
steered in this manner to her destination a distance of 2000 miles, and
this jury steering gear proved efficient.
JURY RUDDER.
When the rudder carries away at sea it will bang from side to side
with the motion of the sea, unless it is possible to secure it hard over
to one side or the other, and very probably the gudgeons and rudder
post may be damaged, but even after getting rid of it considerable
ingenuity will need to be exercised in devising and riggmg up a jury
rudder from the material on board capable of steering the ship. Much
will depend upon the state of the weather, the size of the vessel, her
draught and the practicability of working under her counter at sea. It
would be a pretty hopeless task trying to rig up a working apparatus to
steer a ship with a cruiser stem, but with an elliptical stern and the
ship not too deeply laden an efficient jury rudder can be fitted at sea by
the exercise of patience and perseverance as proved by the successful
effort of Captain D. Forrest in the ss. Braddovey when her rudder was
lost in the North Atlantic. The figure and explanation are from the
Dolphin and Guild Gazette of January, 1929, by kind permission of The
Imperial Merchant Service Guild, and will give an idea of the job when
finished, but not of the strenuous and anxious time put in by those on
board during the dangerous and tedious operation.
EXPLANATION OF PLANS, Etc.
The wire used was 2J inch flexible steel, and by using thimbles in the
eyes and movable fairleads and blocks no chafe or wear was encountered.
The derrick used was a 43ft. steel cargo derrick, the spider-band at the
head being used for the topping lift and steering wires. The goose-neck
being fitted into the gudgeon on the stem post, packed with a brass
bush and secured by using a washer and two collars each with two finch
336
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
screw locking bolts. Again no chafe or wear was encountered and the
gudgeon remained undamaged. The two 5 ft. by 3 ft. iron doors were
fitted on each side of the derrick 4 ft. from the spider-band (to clear
topping lift) and bolted with twelve J inch bolts, six on either side of the
derrick. Between the doors the space was packed with wood to make
the whole firm and solid, and the edges of the doors were again bolted.
The long leads for the steering wires were used to allow any jerks to be
taken up and a spring buffer was also used for this purpose. Length
of derrick, 43 ft. X10 in. (diam.); dimension of doors, 5 ft. x3 ft.; height
of goose-neck above water line, 5 ft.; wires and topping-lift, 2£ ins.
(steel mooring wire).
TOWING A DISABLED VESSEL.
Towing. —It is hardly necessary to touch upon the towing of vessels
by tugs in smooth water. It will be mo-re to the purpose here to consider
the best arrangement for towing in bad weather, or in the case of a
steamer falling in with a disabled vessel and agreeing to take her in tow.
Most modem vessels are now provided with steel wire towlines, of
size proportionate to the size of the vessel, and with a coir or manflfl.
spring of equivalent strength for use in connection with the wire hawser
TOWING
337
to afford the necessary elasticity which is lacking in the wire. Under
ordinary conditions of wind and weather this is safe enough, but for bad
weather a better arrangement is obtained by shackling the steel towline
to the cable of the vessel to be towed, and veering out a good long scope,
after which the cable is secured aboard in the same manner as if the
vessel was at anchor. The weight of the cable will cause it to form a
catenary, which will prevent sudden jerks.
It must be noted that the length of the towline is a most important
point. The longer it is the more uniform will be the tension during the
time of towing, the aim being as far as possible to secure a steady strain
and to avoid slackening and consequent sudden tightening. Therefore
no hesitation should be made when using the cable in paying out plenty
of scope.
Where a disabled vessel is being taken in tow by a steamer there
may be some difficulty in devising a safe arrangement for making the
towline fast to the towing steamer, as the bollards or bitts m the after¬
part of a vessel are not usually fitted with the view of towing other
vessels in bad weather.
A steamer picked up a disabled steamship in the North Atlantic
and established towing connection as follows. The disabled ship
unshackled a cable from her anchor which had a stock and was secured
on forecastle-head. A boat was got ready for lowering to run out a
small line across to the rescue; heavier lines and wires were also in
readiness.
The rescue hove up cable out of the locker, knocked out the 15-
fathom shackle and continued heaving out cable, dragged the end
aft along the fore well deck, over the bridge deck, right aft to the poop
and passed the end through the after leads in readiness for shackling
on to the end of the other vessel’s cable when it was hove up to the
stem.
Everything being in readiness on board both ships the steamer
was manoeuvred as close as possible on the lee bow of the disabled ship,
but ready to instantly go ahead should they get too close, both vessels
being about beam on to wind and sea. The boat was lowered, the
small line run across and passed on board, the rescue heaving in and the
disabled vessel bending on heavier lines and then a heavy wire. The
end of this wire was lashed to her cable a few links up, leaving the end
and shackle free.
The cable was hove close up to the stem of the rescue and as quickly
as possible the cables of the two ships were shackled together and towing
338
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
commenced, the disabled vessel paying out cable as desired. The
cable of the towing vessel was led between the bollards aft and lashed
to the other bollards along the deck to the windlass. It lay quiet and
easy and did not surge under the strain. The tow was comfortably
performed in Atlantic weather.
A great advantage is gained when towing in a seaway if the towing
steamer distributes oil, which will make a smooth for the towed vessel.
When the weather is such as to make it dangerous for the two
vessels to come near each other, communication may be established by
means of the line-throwing gun.
, How to Make a Towrope Fast for an Ordinary Tow
The Wrong Way to Make the Towrope Fast*
Fig. U.
A Better & Safer Way of Making the Towrope Fast .
Fig. 15.
Fig. 14 represents how a towrope should ncf be made fast. By
this method the greater strain comes on the after bitt, which might be
the cause of the bitts lifting aft and being tom out.
Fig. 15 shows a safer way. Here the greater strain is taken by
the forward bitt, and though the after bitt has some they should hold
the ship under ordinary conditions. If the rope is backed to another
pair, further aft, greater security is obtained.
TOWING
339
Dry Docking.—The dockmaster must be furnished with particulars
as to the work to be done on the ship’s bottom when in dock, and the
repairs, if any, which are to be executed. He should also be made
acquainted with the vessel’s draught, whether she has bilge keels, and
any other special characteristics of the ship’s build which may be necess¬
ary as a guide to him m making preparations for receiving the ship
in dock and m the fixing of the keel blocks. Special precautions will
be necessary where a vessel has received damage to her hull through
having been stranded or been m collision.
If possible, the ship should be a few inches by the stem and should
be quite upright Slack water is the time for entering, and after arrival
at the entrance the vessel is under the charge of the dock company.
If being docked for the purpose of cleaning and recoatmg the
bottom, some responsible person on behalf of the ship should see that
the work is done efficiently, especially so when work is being done after
dark. Anti-corrosive paint or anti-fouling composition should not be
put on a wet or damp surface if it can possibly be avoided. A careful
examination of the ship’s bottom should be made, and the engineers
should examine the stern tube, propeller, injection valves, and sea
connections, also if any part of the plating is found to be corroded or
pitted it must be thoroughly cleaned and covered with some anti¬
corrosive coatmg. See also page 614.
Lloyd’s recommend the dry docking of ships as soon after launching
as may be possible, for the purpose of cleaning and recoating the bottom.
To Construct a Raft.—Take the three stoutest spars available and
lash them together in the shape of a triangle. Strengthen the comers
by lashing short stout spars across them, 2 or 3 feet inside the cross
lashings. Inside each corner lash empty barrels or tanks if obtainable.
The raft must then be decked over with good stout spars and planks,
lashing or otherwise securing them to the framework formed by the
triangle. Erect a spar for a mast, with stays to each corner to support
it, have the heel well secured, and fit a suitable sail to it. Round about
the mast lash barrels of fresh water, and store the provisions in tanks if
possible. Life lines should be run round the raft from comer to comer.
Rescuing the Crew of a Disabled Vessel in Heavy Weather.—If in a
steamship, get to windward of the distressed vessel, as near as is safe,
and lie to with the wind and sea two or three points on the weather bow.
Get the lee life-boat ready for lowering and call for volunteers. Man
the boat before lowering, and let each man have a life-belt on. Before
lowering, pass a good long line for a painter right forward to the bow
340 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
of the steamer; also pass a line round each boat fall to frap them inj
and thus prevent the boat swinging out and coming back violently
against the vessel when being lowered.* See that the boat is well
supplied with oil, and bags for distributing it; also one or two spare
life-belts. Before lowering the boat smooth the surface of the sea
with oil, and then lower the boat into the water, and get clear of the
vessel as quickly as possible. The steamer should remain m position
to afford a lee shelter to the boat when going to the wreck.
The boat on approaching the vessel should be careful to look out for
any floating wreckage. The people on the distressed vessel should be
hauled into the boat by lines, with life-belts on. Oil should be used,
both from the distressed vessel and from the boat.
In the meantime the steamer should have gone to leeward in readi¬
ness for the return of the boat. When the boat returns, if unable to
come near enough to get the people aboard, the rescued people should
be hauled aboard by a whip from a yardarm, or from a derrick well
guyed out, oil again being plentifully distributed.
If the rescuing vessel is a sailing ship, it may not be possible to get
to windward. In this case, if a rescue is to be attempted, lie to to lee-
. ward and distribute a good coating of oil. The distressed vessel and the
rescuing vessel will be drifting to leeward, and the oil will make a smooth
wake to windward for the boat and make it much easier to get to the
distressed vessel.
THE SHIP’S LOG BOOK
1. For what purpose is a snip’s log book kept?
To record tne snip’s progress so that her position by dead reckoning
may be found at any time, and it is an important book of reference
with respect to any thing that occurs on board. Also in case of damage
to cargo—entries in the log book showing how the damage arose would
be valuable evidence.
2 Would you keep it in civil or astronomical time?
In civil time; that is, each day on one page, commencing at midnight
and terminating the following midnight.
3. What are the usual daily entries to be made when at sea?
The courses steered, and distance by the log for each hour. Direction
and force of the wind. Leeway (if any), also variation and deviation
* Choose the most favourable opportunity for lowering, when the vessel is as
steady as possible.
THE LOG BOOK
341
of the compass. Any allowance made for the set and drift of the
current. The ship's position at noon by observation if possible; also
position by dead reckoning worked from position at previous noon;
also position at any other times if sights are taken. Times during
which the Regulation lights are exhibited Names of men on the
lookout. Soundings of pump wells. Barometer and thermometer
readings. Work done about the ship. Sail set or taken m, etc.
In a steamer I would also note any orders given through the
telegraph to the engineers, distances on the patent log, and all other
items of importance.
4 What entries would you make in heavy weather?
The kind of sea that was running, that is, whether a cross sea or a
very high sea, etc , also how the vessel was behaving and whether
shipping heavy seas, etc.; what sail was set; also I would note if she was
labouring heavily, or if there was any evidence of straining in any part
of the vessel, and if anything was carried or washed away. In a steamer
I would note how the engines were going, if the propeller was racing
much, hatches inspected, etc.
5. Why is it important to have entries of bad weather in the log book?
So that in case the cargo gets damaged through stress of weather,
the log book may be produced in evidence thereof.
6. What entries would you make after anchoring in a river or harbour?
Depth of water, anchor let go, amount of cable out, direction of
wind and tide, the state of the weather, barometer reading, and the
bearing of some fixed objects ashore.
7. What entries would you make after taking soundings?
The time, depth of water, nature of ground; also distance on the
patent log, and the estimated position of ship.
8. What entries would you make going along a coast?
The time of passing the principal points, and distance off them
when abeam; also ship’s position by cross bearings, sextant angles, or
any other means when opportunity for doing so arises.
9. What entries would you make if you experienced foggy or thick
* weather?
The time it came on and at which fog signals were started, speed of
342 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
vessel, sails set (if sailing vessel), and how engines were going (if in a
steamer). Any orders re engines, and times they were given.
10. Would you make any entries in port?
Yes; 1 would put down the hours during which discharging or
loading was carried on, and amount put out or taken in, if possible,
also the draft both aft and forward. If any delay was caused by rain,
etc., I would make an entry of it, or any other item relating to the cargo
which was worthy of notice. Also work performed on board; or if she
was dry-docked, I would particularise as to what was done. Also if
any repairs were made I would note them.
11. Where does the mate get the necessary particulars from for entering
in the log book?
From the deck or rough log which must be filled in by each officer
at the termination of his watch.
12. State any other important points regarding the log book.
If any damage to, or loss of, cargo arises during the voyage, a full
account of the cause thereof, and the consequent measures adopted for
its protection, must be entered in the log book.
The draught of water should always be entered on leaving port.
No erasion should ever be made, and great care should be taken to
avoid having to make any alteration. If any alteration is necessary,
it should be made by ruling a line through the part required to be
altered—hut not so as to render it illegible—and the correction should
be then made and must be initialed and dated.
CHAPTER XIT.
MENSURATION.
WEIGHTS AND MEASURES?
Troy Weight.
24 grains
= 1 pennyweight
20 pennyweights = 1 ounce
12 ounces
= 1 pound
Avoirdupois Weight.
16 drams
— 1 ounce
4 quarters
= 1 hundredweight
16 ounces
= 1 pound
20 hundredweights
= 1 ton
14 pounds
= 1 stone
2240 pounds
— 1 long ton
28 pounds
= 1 quarter
2000 pounds
= 1 short ton
Lineal Measure.
12 inches
= 1 foot
5280 feet =
1 land mile
3 feet
= 1 yard
6080 feet =
1 nautical mile
6 feet
= 1 fathom
1760 yards =
1 land mile
5 J yards
= 1 rod or pole 3 miles =
1 league
40 poles
= 1 furlong
600 feet =
1 cable
8 furlongs
= 1 mile
10 cables =
1 admiralty mile
69-g- land miles or 60 nautical miles make 1 degree (1°), which is one
three hundred and sixtieth part of the earth’s circumference. Nautical
miles X1 -151 =statute miles.
Surveyor’s Land Measure
In measuring land, surveyors use a chain (called Gunter’s chain)
which is 22 yards long and is subdivided into 100 equal parts, each of
which is called a link.
Thus 100 links = 1 chain = 22 yards
10 chains = 220 yards = 1 furlong
343
344 NICHOLLS’s SEAMANSHIP AND NAUTICAL KNOWLEDGE
Square Measure.
144 sq. inches = 1 sq
foot
40 perches
=
1 rood
9 sq. feet = 1 sq yard
4 roods
=
1 acre
30J sq yards = 1 sq. rod, sq. pole
4840 sq. yards
=
1 acre
or perch
640 acres
=
1 sq. mile
Cubic or Solid
Measure
1728 cubic inches ==
1 cubic foot
27 „
feet =
1 cubic yard
40 „
feet —
1 shipping ton merchandise
35 „
feet =
1 ton sea water
36 „
feet =
1 ton fresh water
40 to 43
feet =
1 ton coal
100 „
feet =
1 ton register (ships)
Liquid Measure.
4 gills
= 1 pint
54 gallons
= 1 hogshead
=
1|- barrels
2 pints
= 1 quart
72 gallons
— 1 puncheon
=
2 barrels
4 quarts
= 1 gallon
108 gallons
= 1 butt
—
3 barrels
36 gallons
= 1 barrel
6J gallons
= 1 cubic foot fresh water = <
62£ lbs.
10 pounds
= 1 gallon fresh water
224 gallons
= 1 ton fresh water
1 cubic foot sea water = 64 lbs.
Dry Measure.
2 pints
= 1 quart
4 pecks =
1 bushel
4 quarts
= 1 gallon
8 bushels =
1 quarter
2 gallons
== 1 peck
5 quarters =
1 load
Measures of Time.
60 seconds
== 1 minute
23h. 56m. 4s.
— 1 sidereal day
60 minutes
= 1 hour
365 days
= 1 year
24 hours
= 1 solar day
366 days
= 1 leap year
Angular Measure.
60 seconds ("} = 1 minute 360 degrees (°) =1 circle
60 minutes (') ~ 1 degree 180 degrees (°) = icr = 3*1416r
90 degrees (°) = 1 quadrant
Circumference of the earth == 24,855 miles (approx.)
Diameter of the earth = 7900 miles (approx)
WEIGHTS AND MEASURES
345
METRIC SYSTEM OF MEASUREMENT.
The metric system of measurement was first introduced by the
French, and is now adopted by most European countries. The lineal
measure is based on the length of the metre, which is one ten-millionth
part of the distance from the equator to the pole, 3*281 feet.
The units of length, capacity and weight are called the metre, litre.
and gramme respectively. Multiples of these units are obtained by
prefixing to them the Greek words deca (10), heeto (100), and kilo (1000),
the divisions being obtained by prefixing the Latm words deci (rfr)>
centi (tw), and milli (two)- These prefixes form the key to the entire
system.
Measures of Length.
1 millimetre
=
0*039
inches
10 millimetres
= 1 centimetre
=
0*394
inches
10 centimetres
= 1 decimetre
=
3*937
inches
10 decimetres
= 1 metre
=
39*371
inches
10 metres
= 1 decametre
=
10*936 yards
10 decametres
= 1 hectometre
=
109*363 yards
10 hectometres
= 1 kilometre
=
1093*63 yards
Measures of Volume and Capacity.
1 millilitre
=
0*061
cubic inches
10 millilitres
= 1 centilitre
=
0*61
cubic inches
10 centilitres
= 1 decilitre
=
6*10
cubic inches
10 decilitres
= 1 litre
=
61*02
cubic inches
10 litres
— 1 decalitre
0*353
cubic feet
10 decalitres
= 1 hectolitre
=
3*53
cubic feet
10 hectolitres
= 1 kilolitre
35*31
cubic feet
I litre is equal to the volume occupied by 1 cubic decimetre.
Measures of Weight.
1 milligram = 0*0154 grains
10 milligrams = 1 centigram — 0*154 grains
10 centigrams = 1 decigram = 1*54 grains
10 decigrams = 1 gramme = 15*43 grains
10 grammes — 1 decagram = 154*32 grains
10 decagrams = 1 hectogram = 0*22 lbs. avoirdupois
10 hectograms = 1 kilogram = 2*204 lbs. avoirdupois
1000 kilograms = 1 ton =2204 lbs. avoirdupois
1 gramme is the weight of X cubic centimetre of pure distilled water
at a temperature of 39*2° F.
N
346
NICHOLLS’S SEAM ANSHUT AND NAUTICAL KNOWLEDGE
MISCELLANEOUS SHIP WEIGHTS AND MEASUREMENTS
Metals. Woods.
Steel
489 lbs
per cubic foot
Oak 34 lbs. per cubic ft.
Copper
550
>>
Pitch pine 40 „
Zinc
445
99
Elm 45 „
Lead
712
99
Teak 50 „
SHIP LIFE-BOATS.
LxBxDx Coefficient = cubic capacity. Average coefficient = *6
Cubic capacity -f- 10 = maximum number of persons to carry
„ = volume of buoyancy tanks in feet
CARGO SHIPS MUST CARRY—
Life-boats under davits on each side to accommodate all bands.
Life-buoys.—Six painted white and red, at least 3 fitted with seJf-
igtiition lights, one buoy to be carried on each side of the
bridge and one on each side of the ship with a 15-fathom
life-line attached to it.
Tests.—Life-buoy to float 32 lbs. of iron in F.W. for 24 hours.
Life-belt to float 16J lbs. of iron in F.W. for 24 hours.
MATERIALS.
Chain. —Breaking strength about 30 D 2 where D is the diameter.
Proof load „ 12D 2
Safe working load „ 6D 2
Wire. —Breaking strength about 2C 2 for 12 wires per strand.
„ „ 3C 2 24
„ HO 2 37
Working load about one-sixth the breaking strength.
Manila-—Ultimate strength about JC 2 and one-sixth ultimate strength
is a safe working load; £ C 2 for occasional lifts.
" 71 Vv
Purchases. —General equation. where S is the pull on
hauling part, P the theoretical power of the purchase,
W the weight to be lifted, n the number of sheaves in the
purchase.
WEIGHTS ANI> MEASURES
347
STOWAGE FACTORS.
The stowage factor is the average cubic space occupied by 1 ton
weight of cargo as stowed on board the ship after making reasonable
allowance for broken stowage, dunnagmg and the packing of the goods.
We give some of those approximate figures here for a few of the more
common class of goods, based on experience of shipments.
Stowage Factors in Cubic Feet per Ton Weight.
Bags. —Nitrate 34, Cement 35, Guano 40, Sugar 42, Meal 45, Flour 45.
Beans 50, Bice 50/70, Seeds 50/90, Ginger 60/80, Coconuts 100,
Nuts 180/200
Bales. —Gunnies 65, Jute 65, Rubber 65, Linoleum 70, Cotton 80,
Hemp 90/100, Coconut Fibre 100, Esparto Grass 100, Flax 100/150,
Bark 140, Cork 300/400
Barrels. —Beer 55, Flour 60, Greases 62, Oils 60/65, Whisky 66/72,
Apples 100.
Bulk. —Steel 12, Ores 12/20, Railway Iron 15, China Clay 24, Patent
Fuel 35, Coal 40/45, WJieat 47, Copra 75, Coke 90.
Cases. —Dates 45, Figs 50, Currants 50, Canned Goods 60, Preserved
Meats 60, Wines 60/65, Rubber 70, Coconut 70, Beer 70, Apples
90, Cinnamon 100, Nuts 120, Matches 100/120, Eggs 100.
Casks. —Cement 40, Molasses 55.
Drums. —Gasoline 60, Oils 70.
Glass 50.
Paper in Rolls 90.
Oil in bulk varies from about 36 to 43 cubic feet per ton depending
upon the specific gravity and temperature of the oil.
GEOMETRICAL FIGURES.
The Perimeter of a figure is the sum of all its sides and is
designated by the letter 8.
a
a
Square.—
Perimeter —4a
Area—side squared— a*
348
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
1 _
Rectangle.—
b Area=length X breadth=Z X b
a B
Triangle.—
(i) Area=half baseXheight—J axh
(ii) area= y' 5 ( 5 ~a) ( s—b ) (s—c)
where s—% (a+6+c)
(in) area=-| a b sin C—\ a c sin B
Circle.—
Circumference —2m
22
it=3*1416, or — approximately
r is the radius of the circle
Area=7rr 2
Arc of Circumference =
Area of Sector = | r 2 0
Area of Segment —\ r 2 (6—Sin 0°)
where 0 =
I
Box-shaped body.—
The surface area is the sum of the areas of
its six sides.
Area==top+bottom+2 sides+2 ends
Volume—length Xbreadth X depth=Jx&Xd
AREAS AX1> VOLUMES
M9
Cylinder.—
Area=areas of ends-f area of curved surface
Volume —~ r 2 l
t: r 2 —area of the end and Z—length
Barrel.—
Volume=7T r 2 l, where r is the mean of the
end radius and bilge radius, and l the
length of the barrel
Wedge.—
Area—areas of top + bottom-f~end+both
sides
Volume—^ (length X breadth X height)
=4 (Ixbxh)
Sphere.—
Area=4 re r 2
Volume =t-Hl S
3
Volume of the shell of a hollow sphere
=|»(i* 3 -* 3 )
Cone —
Area of surface =curved surface +base
—“ r Z+ 7t r 2
where Z=slant height
Volume =area of base X £ perpendicular
height
Pyramid.—
Axea=sum of areas of triangles of which
it is composed-f-area of base
Volume=area of base X J perpendicular
height; the same as for a cone
Triangular Prism.—
Area=area of ends+area of sides
Volume =area of base X height
S50
NIGHOLLS’S SEAM ANHTIP AND NAUTICAL KNOWLEDGE
Example .—Required the capacity in gallons and tons of fresh
water of a tank measuring 16 ft. X 6 ft. X 10 ft.
Volume=16 X6 X 10=960 cubic ft.
Capacity in galls =960x6j=6000 galls.
Capacity in tons=960-r36=26§ tons
Example .—How many lbs. of mixed black paint would be required
to give one coat to a funnel 50 ft. long and 20 ft. in diameter, if 1 lb of
mixed paint covers 70 square ft.
Area of funnel=circumference X length
„ =2 7t rXl
2 22 10 50
- = i x 7 X T x 7
„ =3143 sq. ft.
3143
Weight of paint—- — - = 44 9 lbs.
Example .—A topside trimming tank is uniformly triangular in shape
throughout its length. The end measures 12 ft. X 10 ft. X 14 ft. and
the tank is 30 ft. long; find its capacity in ton% of salt water.
Volume—area of end X length
„ =*\/s ( s—a) (s—b) (s—c)Xl
„ =yl8x 6x8x4 X 30
„ = 58-8x30
„ = 1764 cub. ft.
„ . 1^64 _ , t
Capacity=-——50*4 tons
Example .—Find the reserve buoyancy in salt water of a barrel 4 ft.
1 in. long, end diameter 20 in., bilge diameter 28 in. and weighing 50 lbs.
Volume =tc r 2 l
22
T
12 X 12 49
X -y.- X y= 12-83 cub. ft.
An equal volume of water supports 12-83 X64 - = 821 lbs.
Weight of barrel - - - - - = 50 .
99
Reserve buoyancy -•-*- = 771 „
AREAS AND VOLUMES
351
Example.-- Find the space required to stow—*
(i) 100 rolls paper, length 36 in., diameter 32 in.
(ii) 400 tons sugar in bags, stowage factor 42
(iii) 200 bales, 4 ft. X2 ft. X2 ft. 6 m.
(iv) 1000 cases, stowage factor 60
If the freight is 35s. per shipping ton measurement less 5 per cent.
required the net freight.
^ , .,22 16X16 36 1
(l) Paper,volume tt l = ~ X — — X y X — -
= 1676 cub. ft.
(ii) Sugar volume 400x42 = 16,800
(iii) Bales „ 200x4x2x2*5 = 4000
(iv) 0ase3 ,, 1000 x 60 X 60,000
Divide by 40)82,476 cub. ft.
Shipping tons measurement 2061*9 tons
2062 ton$ at 35s. .... £3608 10 0
less 5 per cent. - - = 180 8 6
Net freight ----- £3428 1 6
Example .—A compartment measures 10,000 cubic feet and is to be
filled with a total weight of 400 tons made up of bales stowing at 60
cubic feet per ton and pig lead stowing at 10 cubic feet per ton.
Required the maximum tons and cubic capacities of each that could be
stowed in the compartment.
This involves a simultaneous equation. Let x = the bales and y
the lead, then (i) x + y = 400 tons weight
and (ii) 60 x + 10 y = 10,000 tons measurement
multiply (i) by 10 10 x + 10 y = 4000
subtract
50 x = 6000
x = 120 tons bales
x + y — 400
y = 280 tons lead
120 cons bales X 60 = 7200 cubic leet
280 tons lead X 10 — 2800
9 *
352
nicholls’s SEAMANSHIP and nautical knowledge
Example .—How many square feet of plating are required to make
a rectangular tank 10 feet long, 6 feet broad, 4 feet high? (Add 10
per cent, for overlapping edges )
Area =2 sides +2 ends+top and bottom
„ =(2xl0x4)+(2x6x4)+(2xl0x6)
,, = 80 -f- 48 -{- 120
„ = 248
add 10 per cent. 24*8
Total 272*8 square feet
See Nicholls’s Concise Guide, Volume I., Chapter IV., for further
Examples and Exercises in Mensuration.
SIMPSON’S RULES ARE METHODS FOR MEASURING THE AREAS
ENCLOSED BY PARABOLIC CURVES.
As ship-shape curves very closely resemble parabolic curves no
appreciable error is introduced by utilising Simp-on’s Rules ni calculating
areas and volumes of vessel’s waterplanes and cubic capacities I»
measuring the area of a waterplane it is usual to calculate the half arei
first and multiply the result by two. The centre line of the waterplane
is first drawn to any convenient scale and this is divided into an equal
number of parts by an odd number of ordinates.
C
Simpson’s First Rule.—In Fig. 1 A B represents the midship line of
the waterplane; lines denoted by the letters a 9 b , c, d, etc., are the dis¬
tances from the midship line to the edge of the waterplane AC B and
are termed ordinates. The spaces between these ordinates are all
equal and are termed the ^common interval.” To find the area of
ABC we multiply the first ordinate by 1, and the last ordinate by X
and the intermediate ordinates by 4 and 2 successively; thus, if we had
SIMPSON’S RULES
353
only three ordinates the multipliers would be 1—4—1; if we had five
ordinates 1—4—2—4—1; and if more than five 1— 4—2—4—2—4—1.
The sum of these products multiplied by one-third of the common
interval gives the area enclosed by the curved line AC B and, as this is
half the vessel’s waterplane, by doubling it we obtain the area of the
whole waterplane.
An easy way to remember the multipliers is to write the figures 1,4,1
in groups of three against the ordinates as follows:—
1-4—1 1—4—1
1—4—1 1—4—1
add 1—4—2—4—2—4—2—4—1
and these are the multipliers for the respective ordinates.
Example —Find the area of the waterplane of a barge, given length
of waterplane=124 feet. Ordinates m feet=3,10,16,19 5,21,19,15*5,
10, 6. As we have nine ordinates given, the common interval is one
eighth of the length=15*5 feet, thus in Fig. 1 the distance between a
and b and between b and c=15*5 feet. The calculation of the area
A C B is then carried out as follows:—
Ordinate
Length of
Ord. Simpson’s
Multipliers F?o ducts
a
3*0
1
30
b
10*0
4
400
c
16*0
2
320
d
19*5
4
780
e
21*0
2
420
f
19*0
4
76*0
9
15*5
2
31*0
k
10*0
4
40*0
h
60
1
60
3480
Area of A G B
348X15*5
1798 square feet
3
Area of waterplane=l798x2=3596 square feet
Simpson’s Second Rule.—Is applied when the area is divided into a
specific number of equidistant ordinates which must be 4 or 7 or 10 or
354
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
13, etc., and placing against the ordinates the figures 1, 3, 3,1, in groups
of four as follows:—
1—3—3—1 1—3-—3—1
1—3—3—1
add 1—3—3—2—3—3—2—3—3—1
and these are the multipliers for the successive ordinates.
The length of each ordinate is multiplied by its respective multiplier
and the sum of the products multiplied by three-eighths of the
common interval gives the area enclosed by the curves. When half
the section only is treated the result will be half the area of the
total surface enclosed.
Example .—The lengths of the half ordinates of a transverse bulkhead
in feet are 20, 18J, 17, 15,13, 9 and 4 respectively, the common interval
between them being 4 feet. Required the total area of the bulkhead.
Example .—Suppose we were asked to find the volume of the vessel,
outlined in Figure 3, enclosed between bulkheads a and e which are each
spaced 30 feet apart. We would, in the first instance, find the half area
of each bulkhead from its figured dimensions, as indicated in the previous
example, either by Simpson’s First or Second Rule whichever we found
most convenient. *>
Let these areas be as follows:—
Bulkhead - - - - a b c d e
Area in sq.ft. - - - 100, 350, 630, 450, 200
SIMPSON’S RULES
355
Fig 3.
The area of each bulkhead now becomes the ordinate in finding the
cubic capacity and, as there are five of them, the 1—4—1 rule will apply,
the work to be arranged in the following order.
\ Ordinates
Multipliers
Products
a 100
1
100
b 350
4
1400
c 630
2
1260
d 450
4
1800
<? 200
1
200
4760
30
4760 X j
«as
47,600 cub. ft.
2
Total volume
95,200 cub. ft.
The displacement of this volume in salt water would be 95200-r
35=2720 tons.
A closer spacing of the bulkheads, or rather, ordinates, as it is not
necessary to actually build in the transverse areas and we have merely
shown them in the figure to help out our explanation, a closer spacing
would give a closer approximation to the actual volume.
Shipbuilders, however, prefer to calculate the enclosed volume of
a considerable part of a ship by using horizontal transverse sections
rather than vertical transverse sections as in the preceding example.
Simpson’s Buies are based on the assumption that the boundary
of the curvilinear area conforms to a parabolic curve, so that results
will be only approximately correct when the curve departs from a
parabola.
556 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
EXAMPLES FOR EXERCISE.
I. The externa] and internal diameters of a steel tube 14 feet long
are 12 inches and 10 inches respectively, find (1) the volume of the
enclosed space, (2) the volume of the steel forming the tube, (3) the
weight of the tube, the specific gravity of steel being 7*84
2. An awning is 25 feet long and 15 feet wide, find its area and the
length of the rope round its edges.
3 A jib is laid flat on deck. The foot measures 20 feet long and
the length from foot to head, measured perpendicular to the foot, is 40
feet. Required the number of square yards of canvas in the sail.
4. A boat’s standing lugsail has the following measurements:—
Head 10 feet, luff 8 feet, foot 12 feet, after leach 16 feet, diagonal from
throat to clew 14 feet. What is the area of the lugsail?
5. A prohibited area, triangular in shape, is marked off in a harbour
by three buoys, A , B and C. The distance from A to C is 300 yards,
from B to C 400 yards, and the horizontal sextant angle at buoy C
subtended by the buoys A and B is 45°. Required the area of the
enclosed space.
6. Find the surface area of a rectangular case measuring 6 feet
long, 3 feet broad and 2*5 feet deep.
7. Find the surface area of an oil drum 2 feet high, its diameter
being 1 foot.
8. Find the total surface area of a wedge of height 3 feet, slant
length 5 feet, base length 4 feet, breadth 2 feet.
9. Find the volume of a tank 10 feet long, 8 feet broad and 20 feet
deep How many gallons of fresh water will it hold?
10. Find the volum* of a cylinder whose length is 12 feet and
diameter 6 feet. Refer to the figure of a cylinder.
II. Find the gallons of fresh water contained in a barrel 3 feet long
whose bilge diameter is 2 feet and head diameter 1 \ feet.
12. A wedge-shaped heap of coal is piled up in a ship’s hold against
a bulkhead to a height of 10 feet and extending along the ceiling for
15 feet, the breadth being 30 feet. Find how many tons there are,
assuming 42 cubic feet to the ton.
13. A ship sails a circular course round a point and maintains a
constant distance of 4 miles from it until the point alters its bearing 49°.
Required the distance sailed.
MENSURATION
357
14. The barrel of a wire reel is 3 feet in diameter and 3J feet long.
Find (a) how many turns of a 3-inch wire will go on the drum to complete
a single layer, (b) what length of wire will be in the layer?
15 The paddle wheels of a steamer are 21 feet in diameter and make
2000 revolutions. How many nautical miles did the ship go, neglecting
shp?
16. The outer and inner radii of a hollow spherical shell are 8 inches
and 7 inches respectively. Find the volume of the shell.
17. The diameter of a cylinder is 14 inches. What length of steel
bar is required to form a ring to fit inside of it?
18. A ship in rounding a point maintains a constant distance of
3 miles from it whilst the bearing of the point alters 65°. What distance
in miles did she sail?
19. There are 20 turns of wire on the barrel of a winch the diameter
of which is 28 inches. Find the length of the wire in feet.
20. A ship on steaming trials is turning m a circle on port helm.
She takes 6^ minutes steaming at 5 knots to complete the circle. Find
(a) the distance travelled by the ship; (6) the diameter of her turning •
circle.
21. A barrel 3 feet long, bilge diameter 24 inches, end diameter
18 inches, weight of barrel 35 lbs. Required its reserve of buoyancy
in salt water.
22. Eggs and butter are to be stowed in a cold storage chamber
measuring 15 ft. X 20 ft. X 25 ft., the eggs in crates stowing at 100
cubic feet per ton and the kegs of butter at 60 cubic feet per ton. If
the combined weight of the eggs and butter is 90 tons, required the
maximum quantity of each that can be put into the chamber.
23. A marine boiler is 16 ft. I| ins. internal diam. X 12 ft. 6 ins.
long. The furnaces, tubes, etc., occupy 26 per cent, of the volume and
the steam space 30 per cent, of the volume, calculate how many tons
of fresh water the boiler requires to fill it to the working level, and how
long will it take to fill the boiler to this level if the pipe delivers 150
gallons per minute.
24. The pontoon of a floating dock is 560 feet long, 100 feet beam,
and the draft in S.W. with a ship in the dock is 14 ft. 6 ins. there being 600
tons of water in the tanks of the dock. If the weight of the dock with
complete equipment and tanks empty is 12,050 tons, find the weight of
the ship.
358 NICHOLLS’s SEAMANSHIP AND NAUTICAL KNOWLEDGE*
25. Find by Simpson’s First Rule the area of a deck 126 feet in
length, the ordinates being 4, 20, 24, 32, 28, 26 and 6 feet, and the
common interval between them 21 feet.
26. Required the area of the following waterplane 150 feet long,
common interval 25 feet, half ordinates 5,10,12,14,11,8 and 4 feet.
27. Given the following areas of transverse sections with a common
interval of 20 feet, find by Simpson’s First Rule the tons displacement
in salt water: Areas 28, 140, 176, 235, 293, 235, 176, 140, 11 feet
respectively.
ANSWERS.—MENSURATION
1. 7-64 cubic feet, 3-36 cubic feet.
1646-9 lbs.
2. 375 square feet. 80 lineal
feet.
3. 44| square yards.
4. 117-2 square feet.
5. 42,433 square yards.
6. 81 square feet.
7. 7f square feet.
8. 36 square feet.
9. 1600 cubic feet. 10,000 gallons.
10. 339f cubic feet.
11. 45-1*1 gallons.
12. 53|-tons.
13. 3-42 miles.
14. 44 turns, 414f feet
15. 21*7 mile3.
16. ’41 cubic feet.
17. 44 inches.
18. 3*4 miles.
19. 146*6 feet.
20. (a) 3293 feet; (6) 1048 feet.
21. 427 lbs.
22. Eggs 52$ tons, Butter 37^
tons.
23. 31*2 tons at 36 cubic feet per
ton 47 minutes.
24. 10,550 tons.
25. 2982 square feet.
26. 3050 square feet by 1st Rule.
3000 square feet by 2nd Rule.
27. 28,860 cubic feet. 824*6 tons.
CHAPTER XV.
HYDROSTATICS.
The Hydrometer.—The hydrometer is an instrument for finding the
relative density or specific gravity of liquids. The name is derived
from two Greek words, hydor (water) and metro (measure).
The Principle of the hydrometer is based on the law of Archimedes,
which states that “all floating bodies displace a quantity of liquid equal
to their own weight.”
Construction .—The marine hydrometer consists of a
glass cylinder with a bulb on its lower end containing
mercury or small shot to act as ballast to keep the instru¬
ment upright when floating. The cyhnder supports a
stem which carries the scale. The volume of the
cylinder is about 25 times the volume of the stem.
Glass is the best material for use in salt water. If
the hydrometer were made of metal it might become
corroded by the action of the salt, and its indications
would be erroneous. Even when made of glass it must
be kept scrupulously clean and all smears or greasiness
removed by wiping the instrument with a clean soft cloth
before and after use.
The Scale is graduated trom 0 at the top to 25 or 40
at the bottom. The simplest form of hydrometer, but
one inconveniently long, would consist of a rod of
uniform bore, and the longer and thinner the rod the
greater would be its sensibility in detecting differences
of density as measured by the scale, the graduations of
which would be proportional to the volume of the rod
and inversely proportional to its cross sectional area.
The marine hydrometer expresses equal differences of
density for successive divisions, hence the reason why
the graduations become closer towards the lower end
of the scale.
Fig i.
The scale indicates the specific gravity of the liquid in which the
359
360 NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
instrument is floating. If the reading were 24, the specific gravity
would be 1*024 and its density 1024 ounces per cubic foot. When
floating in pure fresh water the scale indicates 0, which means the density
or weight of the liquid is 1000 ounces per cubic foot, or density 1000
ounces per cubic foot. The density of salt water varies in different
parts of the world. In some parts of the Suez Canal where the water is
very salt (the Bitter Lakes) it may be 40 or even higher. In the vicinity
of large fresh water rivers the density of the adjoining sea water might
be less than the density of average “sea water,” which is accepted as
having a specific gravity 1 *025, or density 1025 ounces per cubic foot.
To Use the Hydrometer.—Draw a bucketful from over the side,
making sure that it is not affected by any discharges from the ship.
Place the hydrometer in and spin it round slightly in the centre of the
bucket. When it has lost its up and down motion, and the turning
motion has nearly ceased, the reading on the scale will indicate the
specific gravity. The temperature should be noted before the reading
for specific gravity is taken.
A Standard Temperature of 59° Fahrenheit has been adopted for
marine hydrometers to which all observations should be reduced.
When the water being tested differs from 59° Fahr. a correction to the
reading is necessary if accurate results are required. A Table of
Corrections is given in the Barometer Manual .
The Density of a substance is its weight per unit volume.
_ weight of substance
Density = —------
* volume of substance *
Specific Gravity or “relative density” of a substance is the number
of times that any volume of the substance is heavier than an equal
volume of pure fresh water at a temperature of 4° Centigrade.
„ weight of substance
Specific gravity = ——-:-----
weight of equal volume of water
The density of fresh water may be expressed as
1000 ounces per cubic foot
or 62 J lbs. per cubic foot
or 1 gramme per cubic centimetre
or 1 ton per 36 cubic feet
whatever units of weight and volume are selected.
The density of average sea water is 1025 oz*. per cubic foot or 64 lbs
per cubic foot, but the
HYDROMETER
361
a . weight of 1 cub ft sea water
Specific gravity of sea water=
weight of 1 cub. ft. fresh water
1025
,, =-= 1 *025
1000
The density of mercury is 849 lbs per cubic foot and the
0 . (849 X16) oz. per cub. ft.
Specific gravity of mercury =---
" 1000 oz per cub. ft.
= 13*6 •
BUOYANCY.
Buoyancy is due to the supporting power of the water. All bodies
when immersed in water exhibit an “apparent” reduction in weight.
Everybody experiences this sensation when lying in a bath of water
and Archimedes has the credit of being the first man to establish and to
apply the theory in practice.
It is necessary to recall to mind the following information when
working examples on buoyancy.
1 cub. ft. fresh water
1 cub. ft. salt water
2240 lbs.
224 gallons
1 ton fresh water
1 ton salt water
1 cub. ft.
= 62£ lbs. = 1000 oz.
= 64 lbs.
= 1 ton
= 1 ton fresh water
= 36 cub. ft.
= 35 cub. ft.
= 1728 cub. ins.
Experiment —Find the volume of an object, say a sphere,-
3
(see “Mensuration,” page 349). Suspend the sphere from a spring
balance, as in Figure 2 and note its weight. Immerse the sphere in
I
NTCHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
fresh water and weigh, it again. The spring balance will register less
than before.
Example ,—A sphere of radius 2 inches weighs 40 ounces in air,
what will it weigh when suspended in water?
_— . 4 7C r 3 4 22 8 ^ . . ,
Volume =-- X— X- = 33*52 cubic inches
3 17 3
tT1 ^ , . 33-52 in. X 1000 oz. _
Volume 33*51 cub. ms. water—-—- =19-4 oz.
1728 m.
Sphere, volume 33*52 cub. ins. weighs 40*0 ounces in air
Water, volume „ „ 19*4 ounces
The sphere weighs in water
20*6 ounces
Example .—A block of concrete weighing 2 tons and measuring 30
cubic feet is lowered by a crane into sea water, what weight is the
crane then supporting?
Weight of block in air (2 X2240) = 4480 lbs.
30 cub ft. salt water supports (64 X 30) = 1920 „
Weight of block in water - - = 2560 lbs.
Another way of setting this type of question would be to say that
a block, 30 cubic feet and of density 149*33 lbs. per cubic foot, is
immersed in Sea water, required its loss of weight.
Loss of weight = (30x149*3) — (30x64)
„ = 4480 — 1920 = 2560 lbs.
Example .—A rectangular tank 6 ft. X 4 ft. X 3 ft. floats in fresh water,
its draught being 1 foot, what does the box weigh?
Volume of displaced water = 6 ft. x4 ft. xl ft. =24 cub. ft.
Weight „ „ = 24 ft. X 62 Jibs = 1500 lbs.
The weight of tank is 1500 lbs.
What weight must be put into the tank to sink it 6 inches in salt
water?.
The weight will be equal to that of the volume of water to be
displaced, viz., 6 ft. X4 ft. x *5 ft. =12 cub. ft.; 12 ft. X64 lbs.=768 lbs.,
the weight required.
WATER PRESSURE
363
Pressure is somewhat different from density. The pressure of the
water is exerted equally in every direction, upwards, downwards and
sideways. The pressure of water increases at the rate of 64 ibs. per
square foot of area for every foot depth of water. Think of a container,
a square box on a table measuring 1 ft X1 ft X 1 ft. so that the area
of each side will be exactly I square foot. Fill the box with water.
The water is now pressing outwards on every side of the box. The
mean pressure on each side is 32 lbs. per square foot, but this pressure is
resisted by the strength of the container. The water presses downwards
on the bottom of the box with a mean pressure of 64 lbs. per square
foot, but this pressure is supported by the upward force of reaction
exerted by the table. There is only the pressure of tfie atmosphere
acting on the surface of the water.
If another exactly similar box be placed on top of the first the press¬
ure exerted by the water on its sides and bottom will be the same as
in the case of the lower box.
But what is now the effect on the lower box? Obviously the super¬
imposed weight does not add to the pressure exerted by the water in
the lower box, but the additional 1 cubic foot of water does increase the
downward pressure on the bottom of it which has now to support 2
cubic feet of water, or 2 X 64=128 lbs., neglecting the weight of the boxes.
The same reasoning would apply tp our box when empty and immersed
in water with its top edge on a level with the surface. There would
be no water pressure on the top of the box. The upward pressure at a
depth of 1 foot would be 64 lbs. because the area of the bottom ds 1
square foot. The mean pressure on each side would be 32 lbs., because
the mid-point is 6 inches below the surface and *5 ft. x 64 lbs. =32 lbs.
If the empty container were further immersed so that its top waa>
1 foot below the surface then its bottom would be 2 feet down. The
364
fcUCHOLLfe S SEAMANSHIP AND NAUTICAL KNOWLEDGE
pressure on the top would be 1 ft X64 lbs.=64 lbs ; the pressure on the
bottom would be 2 ft. X641bs =128 lbs; the pressure on each side would be
/z &S. —
Fig. 4.
1-5 ft. x64 lbs.=96 lbs. per square foot at any point halfway down the
side of the box.
Example .—Required the pressure in tons on the bottom plating of a
ship at a depth of 20 feet, the area of which is 9000 square feet.
The pressure in lbs. = 64 lbs. X area X depth.
Pressure=64 ibs. X9000 square ft. x20 ft.~2240 lbs.=5143 tons.
Example .—Required the average pressure on a plate 10 ft. by 4 ft.
suspended vertically in water, the top edge being 20 feet below the
surface.
Area of the plate is 10 ft. X 4 ft. =40 sq. ft.
Mean depth is £ (20+30)=25 ft.
Pressure is 64 lbs. X25 ft. (depth) X 40 sq. ft. (area) =64,000 lbs.
Example .—The outer bottom is punctured so that a vessel is floating
on her tank tops which have an area of 30 ft. X40 ft. at a depth of 18 ft.
Required the mean upward thrust of the inner bottom in tons.
Pressure=64 lbs. Xl8 ft. X 1200 sq. ft.^2240 lbs.=617 tons.
1/Slater Pressure Tests* Tanks are tested by a head of water usually
8 feet high. The sea-cock of the tank is opened to allow the water to
run in, and if the level of the sea surface is higher than the inner bottom
the water will endeavour to reach the same level inside the vessel as
it is* outside. If the difierence of level is 8 feet the mean upward thrust
on the inner side of the tank top will be 64 lbs. X8 ft. =512 lbs. per square
foot of area.
The same pressure can be obtained by means of a “stand’’ pipe,
which is just a vertical pipe with its bottom end screwed into a hole in
WATER PRESSURE
365
the tank top. Water is then pumped into the tank until it reaches a
height of 8 feet in the stand pipe. The pressure inside the tank will
then be 64 X 8=512 lbs. per square foot. When pumping up tanks and the
water overflows in the air pipes an excessive pressure is being exerted
on the inner sides of the tank and the pumps should be stopped.
Example .—The level of the watet in the expansion trunk of a tanker
is 6 feet higher than the bottom of the summer tanks the area of which
is 60 ft. X20 ft., what is the upward thrust on the bottom of the summer
tanks which happen to be empty ?
Fig. 6.
64 lbs. X6 ft. X1200 sq. ft.4-2240 lbs.=205'7 tons.
The question of water pressure is a serious one for a deep sea
diver as the atmospheric pressure within his suit and his body has to be
366
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
adjusted by means of an air pump to withstand the coliapsmg pressure
of 64 lbs. per square foot for every foot depth of water he descends.
Water is Non-Compressible.—Air is compressible, but water under
normal conditions is not so m practice. The average pressure of the
atmosphere is 15 lbs per square inch which works out afc 2160 lbs per
square foot, or nearly 1 ton, so that an average sized person having a
surface body area of 10 square feet is built to withstand a normal
pressure of about 10 tons, but the air pressure inside his body is equal
to the external pressure and so he is able to carry on.
The Atmospheric Sounding Tube is based on the compressibility of
the air entrapped in the glass tube, the basis being Boyle’s Law, which
states “that the volume of a gas varies inversely as the pressure when
the temperature is constant.” This may be written
New pressure old volume
Old pressure new volume
The sounding tubes are 24 ins. long and their bores are exactly
parallel throughout their length, one end being sealed and the tube is
lowered into the sea open end downwards. The air in the tube exerts
a pressure of 15 lbs. per square inch, which is equivalent to the pressure
exerted by water at a depth of 33 feet. The pressure
at sea surface is 1 atmosphere = 15 lbs. per sq. in.
at 33 ft. down it is 2 atmospheres = 30 „
at 66 ft. down it is 3 atmospheres = 45 „ etc.
When the tube descends the pressure of the water increases and
rises in the tube, thus gradually reducing the volume of the entrapped
air, the minimum volume being recorded when the ma xim u m pressure
is reached, namely, on reaching the bottom. The tube records the
volume by means of the discoloration; the volume gives the pressure^
and the pressure gives the depth.
Example .—The volume of air left in a 24 in. tube is 6 inches after
_reaching the bottom, required the depth of water.
» Let x represent the depth corresponding to the increase
A. 1 pressure.
1 } New pressure __ old volume
1 „ Old pressure new volume
^ ^ ^ £+33 ft. 24 ms.
J ’ * 33 ft. ^ 6 ins.
*» £+33=33 X 24-f-6=132 ft.
I 05=132—33=99 ft.=16£ fms.
Fig. 7.
TANK PRESSURE GAUGE
367
Note .—Tile tube starts oil with an initial internal air pressure
of 15 lbs. per square inch, the equivalent of 33 feet depth of water,
but x represents the actual depth which we are trying to find
Example .—What would be the length of the volume of air left m a
sounding tube after it has been lowered to 30 fathoms?
*
Volume is asked for in this example.
Xew volume old pressure
Old volume new pressure
x ins. 33 ft.
24ins. ^ "(180+33) ft.
a?=33x24-213=3*71 inches
The scale of depths for K.B B tubes is calibrated for a barometer
reading of 29 0 inches. A reading higher than 29*0 indicates a higher
initial pressure of air within the tube which will be harder to compress
into smaller volume and will give a scale reading too low.
If barometer reads 29 5 add a fathom in every 40 fathoms.
» „ 30*0 „ „ " 30 „
*9 >> 30 5 ,, „ 20 f ,
TANK GAUGES.
The fact of the pressure of liquids increasing with the depth is
applied in the application of hydrostatic gauges to measuring the
height of the surface level of liquids inside tanks, the draught of a
ship, the depth of water in a river at any stage of the tide, or, indeed,
to the alteration of the surface level of any liquid above any desired
datum level. Such apparatus is designed to convert changing pressures
into scaled depths.
The Pneumercator Tank and Draught gauges manufactured by
Messrs. Kelvin, Bottomley & Baird, Glasgow, consist of five essential
parts shown in Figure 8 where (1) is the balance chamber, (2) an air
pump, (3) the mercury gauge calibrated in feet and inches of liquid
depth, (4) a control valve, (5) small solid drawn air piping led from
the chamber through devious paths to the gauge.
Figure 9 illustrates a tank with the air chamber inside of it and
the air pump for expelling liquid from the chamber. It is necessary to
bring the level of the small residual amount of liquid that may collect
r
TANK PRESSURE GAUGE
369
in the chamber to a definite datum level, and this is effected by working
the hand air pump which forces air into the chamber, the excess of
back pressure pushes the liquid back into the tank through a small
orifice at the datum level of the chamber from which air bubbles are
seen emerging in the diagram. This preliminary operation having been
performed the gauge scale will now record the depth of liquid in the tank.
The Principle is illustrated in Figure 10. The downward pressure
of the liquid increases with its depth, or height, and forces its way
through the orifice into the balance chamber. The entrapped air is
consequently forced back through the air pipe line to a cistern of mercury
at the gauge, the mercury being thus pushed back into the bore of the
Trapped Air in Balance-Chamber
Compressed by Heap of Liquid in Tank.
Fig. 10.
tube. The length of the column of mercury in the tube corresponds
to the pressure of the liquid and the scale expresses this pressure in
feet and inches.
If water were substituted for mercury in the gauge glass it would
automatically find its own level, but a scale of the same depth dimen¬
sions as the tank would be required, the air entrapped in the pipe
merely acting as a cushion and serving no useful purpose. But the
specific gravity of mercury is 13*59 so that it compresses into a column
13*59 times shorter than one of fresh water when subjected to the same
pressure, with a corresponding reduction in the length of the scale.
For example, in Figure 10, the head of water in the tank is 3 feet and
370
NICHOLLS’S SEAMANSHIP JTr^D NAUTICAL KNOWLEDGE
the length of the column in a water gauge would be 3 feet, but the
column in a mercury gauge would only be about 2*6 inches, namely, 36
inches divided by 13*59=2*6 inches. A control valve, (4) in Figure 8,
connects the air pump with the balance chamber, or the chamber with
the gauge, or disconnects all three components as required.
The illustration shows a typical ship installation. The balance
chambers are seen in the double bottom tank, the copper air pipe is
carried up above the load water line and down again to gauges in the
engine-room. The filling pipes for running in oil am indicated by
hatched lines.
DRAUGHT INDICATOR
372
DRAUGHT INDICATORS.
The same principle is applied to registering the draught of a ship.
Two balance chambers, one forward and one aft, are placed in a conven¬
ient position agamst the ship’s side below the level of the light load line,
Fig 12.
as in Figure 12, which assumes the ship to be non-existent. The mercury
rises and falls in the gauges whenever the draught increases or decreases
and, in Figure 12, the fore gauge is being operated by the head of watei
Ef \ and the aft gauge by the head Ha.
A structural modification is required for the balance chamber,
as shown in the next Figure (13), where the balance chamber is contained
372
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
in a watertight casing connected to the sea below the light load line
a 1-inch sea-cock and vented to the deck, so that, in effect, the balanc
chamber is immersed in the sea at a fixed position relative to the keel
Fig 14 —Pneumercator Draught Indicators.
In the diagram the head of sea water E is operating the indicator.
Figure 14 shows in profile the lay-out of the pneumercator draught
indicators, the gauges for both fore-and-aft draughts being usually
mounted side by side in any convenient position as selected.
MARKING OF A SHIP.
A ship is required to have in addition to her load line and deck
line marks her name marked on each side of her bows, also her name
and port of registry on her stem. The letters shall be not less than 4
inches in length, and of proportionate breadth. They must be light in
colour on a dark ground, or dark in colour on a light ground. Her official
number and registered tonnage must be cut in on her main beam.
. A scale of feet denoting her draught on each side of her stem and
stern post. The scale may be marked in Roman capital letters or in
figures. The figures must be not less than 6 inches in length. They
are generally made exactly 6 inches in length with a space of 6 inches
between them.
The letters or figures must be cut in and painted a light colour
on a dark ground or in such other way as the Board of Trade approve.
The bottom of the figures indicates an even foot of draught, for example,
the bottom of the 17 feet mark indicates 17 ft. 0 ins.
half way up the 20 feet mark „ 20 3
half way between the 21 and 22 feet marks 21 9
the top of the 24 feet mark indicates 24 6
DRAUGHT INDICATOR
373
Penalties.—If the marking is in any wav inaccurate so as to be Likely
to mislead, the owner of the ship shall be liable to a fine not exceeding
£ 100 .
If the marks are fraudulently altered by any person, the owner,
master, or person shall be liable to a fine not exceeding £100.
The load line marks are closely associated with the tonnage measure¬
ments of a ship defined as follows:—
Under deck tonnage is a measure of the internal space between the
top of the ceiling or double bottom in the hold and the under surface
of the tonnage deck. The unit of measurement is a ton of 100 cubic feet.
Gross tonnage is a measure of the total internal volume of the ship>
and is equal to the under deck tonnage plus the tonnage of all enclosed
spaces above the tonnage deck.
Net tonnage is the residual tonnage after the various allowances for
propelling power, crew spaces, and navigation spaces, have been
deducted from the gross tonnage
Displacement tonnage is the total quantity of water displaced by
the vessel when floating at her load draught.
Deadweight tonnage is the number of tons (of 2240 lbs.) of cargo,
stores, etc., that a vessel is capable of carrying when floating at her
load draught.
Load waterline is the waterline corresponding to the maximum
draught to which a vessel is permitted to load, either by the freeboard
regulations, the conditions of classification or the conditions of service.
Draught is the distance from the lowest part of the keel to the
waterline at which the vessel is floating.
Load draught is the distance from the lowest part of the keel to the
load waterline as defined above. ’
Coefficient of Fineness is the ratio between the actual volume of the
under water shape and the volume of a rectangular block having the
same extreme length, breadth and depth. The coefficient is expressed
as a decimal and varies from about *5 in the case of fine lined yachts
gradually increasing through *6 to *75 in the case of fast passenger
steamers, and to *85 for slow, bluff cargo vessels.
Displacement—length X breadth X draught X coefficient divided by
35 (cubic feet of salt water per ton) when the ship floats in sea water,
and by 36 (cubic feet of fresh water per ton) when floating in fresh water.
Displacements Lx J5xdXcoefficient-~35 for sea water.
374
NICHOLL^S SEAMANSHIP AND NAUTICAL KNOWLEDGE
1. Find the displacement of a vessel, length 500 feet, breadth 40 feet,
mean draught in salt water 20 feet, block coefficient *7.
Ans .—8000 tons. -
2. A vessel 400 feet long, 30 feet beam, and 25 feet mean draught
displaces 5143 tons in sea water. Find her block coefficient and state
what type of vessel you think she might be.
Ans .—Coefficient *6 A steam yacht or a very fine lined steamer.
3. Length 500 feet, breadth 50 feet, mean draught 30 feet, block
coefficient -8. Required the vessel’s displacement in fresh water.
Ans. —16,666 tons.
4. Length 420 feet, breadth 45 feet, mean draught 25 feet, block
coefficient *8. Required the vessel’s displacement in salt water.
Ans. —10,800 tons.
VARIATIONS IN DENSITY AND DRAUGHT.
The hydrometer is used to find the density of harbour water so that
the corresponding increase in draught may be computed. The buoyancy
of all floating bodies is dependent upon the law of Archimedes.
If the density of a body is exactly equal to the density of the water
it will neither sink nor float; if its density be greater the body will
sink, and if less it will rise until the weight of the body is equal to the
weight of the volume of water it displaces. It is obvious, therefore,
that a ship of a given weight will displace more fresh water than salt
water because every cubic foot of fresh water can only support 62J lbs.
weight of the ship whereas 1 cubic foot of salt water supports 64 lbs.
The draught varies inversely as the density, and in the case of box¬
shaped vessels this may be written
New draught old density
Old draught new density
Example .—The mean load draught of Caledonian Monarch is 24 feet
5 inches in salt water, what should her draught be when loading in dock
water of density 1005?
Draught 1025
= 77^ from whicha?=24 ft. 10-8ins.
24 ft. 5 ms. 1005
Draught in dock water 24ft. 10*8 ins
Draught in salt water 24 5-0
Difference in draught
5-8
SEA WATER DENSITY AND DRAUGHT
*375
The foregoing method is not accurate in the case of ships and other
irregularly shaped bodies. A nearer approximation may be got by
assuming the ship to be a hydrometer and the distance between F.W.
and S.W. marks to represent the scale, the top edge of F W being 0
and the top edge of S W being 25, with the intervening distance divided
up proportionately.
Fig. 15.
Assuming the distance between F.W. and S.W. marks to be 5 inches
and to be divided into five parts corresponding to 5, 10, 15, 20 and 25
of the hydrometer scale, then, as in Figure 15, when the dock water
density is 1005 the F.W. mark should be 1 inch clear of the waterline
and 2 inches clear when the hydrometer reads 1010, 3 inches clear for
1015, 4 inches for 1020, and 5 inches for 1025, the density when the
ship should be loaded to the top edge of the S.W. mark.
Example .—The distance between the F.W. and S.W. marks is
Fl/
s w
Fig. 16.
7 inches in the case of Caledonian Monarch , what allowance in draagnt
would be made when loading her in dock water of density 1005?
The difference of draught is to 7 inches as the difference of density
376
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
between F.W. and the dock water (5) is to the difference between F.W.
and S.W. (25)
cc ins 5 35 ,
— : — = — /.£=— =14 ins.
The F.W mark should be 14 inches clear of the waterline, or, the
same result is to submerge the S.W. mark 5*6 inches.
The denominator in inches of the equation is a constant for each
particular ship and the denominator 25 is constant for all ships.
The foregoing methods are near enough for the practical purposes of
loading a ship but it is not strictly accurate for all types of ships, so
the Board of Trade apply the following formula:—
Immersion = inches, where
TxlOOO
D =displacement in salt water up to the centre of the disc
T =tons per inch immersion in salt water at the centre of the disc,
and
d = difference between densities of salt water and the water at the
place of loading
Example.—Caledonian Monarch is loading in dock water (1005), how
much may her S W. mark be immersed?
Referring to her deadweight scale and supplementary notes at
the end of the book we find total load displacement 13,007 tons; pei
inch immersion 47*1 tons; and by introducing these facts into the
above formula we get
_ . 13007X20 * J . ,
Immersion = —-——— —54 inches
474X1000
so there is close agreement between the results of the three methods
viz., 6*8, 5*6 and 54 inches respectively.
LOAD LINES.
The Rules of the International Load Line Conference of 1930 have
now been ratified, and are to be effective for a period of five years
when they will be subject to revision and amendment if necessary.
They apply to all countries of maritime importance. Specific rules
regarding the positions of the various load lines are given for a standard
ship of certain dimensions and superstructures with further modifi¬
cations fox vessels which depart from the standard ship in certain
particulars. *
£OAt> Lt&ES
377
Assigning Authorities.—The British authorities who assign load line
marks are Lloyd’s Register (LR.) ? British Corporation (B.C.) and the
Board of Trade (B.T.). The initial letters of the assigning authority
may be indicated by letters measuring about 4J inches by 3 inches
marked alongside the disc and above the centre line.
The assignment of load lines is conditional upon the ship being
structurally efficient and upon the provision of effective protection to
ship and crew.
D E.C k Lin£
378 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Details of Marking.—Figure 17 indicates the relative positions and
the lengths of the lines, the diameter of the disc and the method of
determining the level of the top edge of the deck line. The disc, lines
and letters are to be painted in white or yellow on a dark ground or in
black on a light ground. They are also to be carefully cut in or centre
punched on the sides of iron or steel ships, and on wood ships they are
to be cut into the planking for at least one-eighth of an inch. The
marks are to be plainly visible, and, if necessary, special arrangements
are to be made for this purpose. All lines are 1 inch in breadth and the
top edge of the respective lines limits the ship’s immersion in different
circumstances and in different seasons.
Actual Freeboard is the distance between the upper edge of the
deck line and the waterline.
Statutory Freeboard is the distance between the upper edge of the
deck line and the upper edges of the respective load lines.
The Summer Load Line is indicated by the upper edge of the line
which passes through the centre of the disc and also by a line marked 8 .
Its position is deduced from the Load Line Tables for any particular
ship.
The Winter Load Line is indicated by the upper edge of a line marked
W . It is \ inch per foot of summer draught lower than S.
The Winter North Atlantic Load Line is indicated by the upper edge
of a line marked W N A and is 2 inches lower than W. It applies to
vessels less than 330 feet in length trading across the North Atlantic
north of latitude 36° N.
The Tropical Load Line is indicated by the upper edge of a line
marked T. It is J inch per foot of summer draught higher than S,
The Fresh Water Load Line is indicated by the upper edge of a line
marked F.
The difference between S and F is the allowance to be made in fresh
water at the other load lines*
The Tropical Fresh Water Load Line is indicated by the upper edge
ot a line marked T jF. The distance S ’to F~T to T F.
The difference between the minimum freeboard in fresh water of
unit density and the minimum freeboard in salt water is determined
by the formula: Disulacement-f-40 Xtons per inch immersion, tne
displacement and the tons per inch being for the summer load waterline.
LOAD LINES
379
-“Si.!,?” ssr-- “•
Displacement
40 X TP I
13007
"40X47
= 7 inches
S ailSn ShiP Tr WU3ter aDd tr0p,cal load hnes are ™>t marked on
Jaden^in «S w maxunum load ^ *® which sailing ships may be
the diT “ ™ ter aDd “ the “ Tr °P^ Zone” is the centre of
LOAD lines for steamers carrying timber
DECK CARGOES.
A Timber Load Line is a special load line to be used only when the
ooMition 3137 ^ 8 4 ! im . ber deck carg0 “ compliance with the special
conditions and regulations applicable to such ships.
380
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
These additional lines are indicated in Figure 19. They are marked
on the ship’s side abaft the centre of the disc, the seasonal lmes being
preceded by the letter L but, otherwise, they have the same significance
I
Fig. 19—Load Lines for Timber Cargoes.
as the ordinary load lines forward of the disc. It will be noted that the
freeboard for a ship when timber laden is less than for other cargoes.
The freeboard for su mm er draught is deduced from the Timber
Load Line Tables for any particular ship and this fixes the position of
the L S mark.
LW is £ inch per foot of L S draught lower than L S.
LT is J inch per foot of L S draught higher than L S.
LW N A is at the same level as W N A.
LOAD LINES FOR TANKERS.
A “tanker” includes all steamships specially constructed for the
carriage of liquid cargoes in bulk, and a series of rules regulates the
minimum freeboard assigned to this particular type of ship.
They have load line marks similar to other steam vessels, but the
W N A mark is 1 inch per 100 feet in length of ship lower than
the winter mark.
Full information with the modifications applicable to ships which
differ in length, sheer, ratio of superstructures to length, etc., from the
basic ship on which the Tables are founded is given in the “International
Convention respecting Load Lines,” price 3s., H.M. Stationery Office.
ZONES AND SEASONAL AREAS.
The various oceans and seas have been divided into “Summer,
Winter and Tropical Zones” having definite geographical boundaries;
LOAD LINES
381
these demarcations, however, are rather long and complex to be recorded
here. To these areas are allotted certain periods of the year which
are to be regarded either as the “Summer season, the Winter season or
the Tropical season/ 5 and during those periods the respective seasonal
load lines on the ship’s sides become the statuatory maximum load
lmes.
LOAD LINE SEASONS.
Areas
Tropical
Summer
North Atlantic
1 Nov -15 July
16 July-31 Oct
North of Lat
36° N.
1 Apr-31 Oct.
Arabian Sea
North of Lat
24° N.
1 Aug -20 May
21 May-31 July
South of Lat
24° N.
1 Dec -20 May
21 May-15 Sept.
South of Lat
24° N.
and
16 Sept -15 Oct
and
16 Oct.-30 Nov.
Bay of Bengal
16 Dec.-15 Apr.
16 April-15 Dec.
China Sea
21 Jan -30 Apr
1 May-20 Jan.
North Pacific
1 Apr -31 Oct.
1 Nov -31 Mar.
South Pacific
1 Apr.-30 Nov
1 Dec -31 Mar.
Baltic *
1 Apr -31 Oct.
Mediterranean
Sea of Japan
Lat 35° N. to 50° N.
16 Mar -15 Dec.
1 Mar -30 Nov.
Winter
l Nov.-31 Mar.
Southern Hemisphere
1 Nov.-31 Mar.
16 Dec.-15 Mar.
1 Dec.-2S/29Feb.
16 Oct.-15 Apr. 16 Apr.-15 Oct.
The boundaries and the seasonal dates for the respective zones are
published and freely circulated so that it is not likely that mariners
will be expected to memorise the above particulars, but they are given
here to indicate the importance and the significance of the various
load lines. See Map.
NOTICE TO MASTERS
MERCHANT SHIPPING ACTS.
Load Line, Draught of Water and Freeboard.
Entries in Official Log Books.
Under the Load Line Regulations dated March 31,1930, the master
of any ship registered in the United Kingdom marked with a load
line will be required as from the 1st October, 1930, to enter in the
official log book the following particulars of draught of water and
freeboard:—
Foreign-going Ships.—(1) The draught of water of the ship as shown
on the scale of feet on her stem and stem post when the ship is so loaded
382
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
THE HEADINGS OF
LOAD LINE AND
Position of the Load line Disc and
The centre of the due b placed at,.. , .. . feet.. , , . ..rsches below the
Kudrntna badSne m fresh W _ above the centre of the disc.
Mixuatsa load hue is qi rp m. y _ r _ . above the deatre of the rl •'«** ,
Maximum load lme m summer the centre of the disc.
Atoor pMruetdart to b* lain from Load kns OrhJUtU.
Ilw aaxfaaem draught of water to moots is the draught of water of the «hfp«* ihowa on the scale of feet on her stem and stem post when
DATES OF DEPARTURE FROM AND ARRIVAL AT EACH DOCK, WHARF,
Upon eBay occasion of dW
DEPARTURES
Dato
mad Hoot
of
Departin'*.
0)
Dock, Wharf PI«c»
<* Harbeos.
Acrcu- Du.com I
o* • |
1 ActcjU. Fiumu 1
| Aktomm • ]
Deadly
of
Water.
.w..
I AUOWAMOt
Forward.
Aft.
- -W-
flEwi
Starboard.
ifea.
(7)
For
Dralty of
Water*
For tutor and
Rubbish.*
00)
ForFMtteW
CoiwuteC on Stnfch
oflBbadWctte,
01)
Ft In*.
Ft 1st.
| Ft la*.;
Ft In*.
Ft In*.
Is*.
Weight In*.
Dbtaaea. I m.
that the upper edge of each line marked “S” is on the surface of the
water and the ship is upright on an even keel {i.e., the mean draught
to the centre of the disc).
(2) The ship's actual draught of water, actual freeboard amidships
and mean freeboard when the ship is ready to leave any dock, wharf,
place or harbour for the purpose of proceeding to sea.
(3) The density of the water.
(4) Allowances if any for fresh wateT, ashes to be thrown overboard
estimated amount of fuel likely to be consumed before reaching salt
water.
(5) The mean draught of water and mean freeboard amidships of the
ship in salt water after deducting the above allowances, if any.
(6) The date and time of recording the particulars of draught of
water and freeboard on the Notice (Form L.L.14).
Home Trade and Coasting Ships.—Masters of these vessels will be
required to record in the official log book the particulars stated in 1
2, and 3 above.
Posting of Notice .
The master of a foreign-going ship is also required to put up in a
conspicuous place on board the ship so as to be legible to all members
of the crew, a Notice (Form L.L. 14) giving particulars of draught ana
freeboard of the* vessel on leaving any dock, wharf, place or har&our
for the purpose of proceeding to sea. The master and first mate will
DRAUGHT OF WATER
383
AN OFFICIAL LOG.
a
DRAUGHT OF WATER.
be Line* used in connection with the Disc
I,,- Auric Line marked under the provisions of the Merchant Shipping Act, 1S94.
Maximum load line in winter-below the centre of the disc.
Maximum load line in winter, North Atlantic_fa» t.-.rnrh an below the centre of the disc.
Maximum draught of water m aimni w---_ . tnrW
U Wtrit wfac* trt not tppUctbU fWi bt i&UL
e ahip a *o loaded that the upper *dfft of each Lae narked "S" w oe the tarftee of the inter tad the ship s» opr-ght os ea even kaeL
LACE OR HARBOUR with the DRAUGHT OF WATER AND FREEBOARD
htfi't pnctedaig to Sea,
[ SIGNATURES. j
[ ARRIVALS.
| »•£•»>
Dn»
aadTtaacf
Date
and Hoar
cf ,
Arrival
Dock. Wharf. Flu*
or Harbour
Total
UlMWCO.
35.
35T
tbaifoS.
CWS.UJO
Mastxx,
XAT*
0*5
(U)
0*f
_ 0«)
G«)
07)
08)
0»)
In. j
Ft In.
Ft Ins.
i
also be required to sign the entry of these particulars. Supplemental
official log books and the authorised form of Notice (Form L.L. 14)
to be used as from the 1st October, 1930, will be obtainable free of
charge from the Superintendents of Mercantile Marine Offices in the
United Kingdom, or from British Consular Officers or Shipping Officers
at ports abroad.
Penalty.—Failure to make the required entries of draught and
freeboard at the proper time renders the master liable under Section 443
of the Merchant Shipping Act, 1894, to a fine not exceeding £100 for
each offence.
QUESTIONS.
1. Describe the marine hydrometer, its construction and the principle
of its flotation.
2. Describe in detail how you would go about getting the density
of sea water when under way.
3 Distinguish between “density” and “specific gravity.”
4. A hydrometer indicates 1015 when floating in water. What
exactly does this mean? *
5. What is meant by buoyancy and how is.it made possible?
6. A caisson when filled with ballast weighs 10 tons and measures
200 cubic feet, what weight will be on the crane when the caisson is
lowered into the water.'
Ans, —4*286 tons.
384:
NICHOLLS S SEAMANSHIP AND JNAUiitAL. ilinu YY-LJ&j-MjJii
7. What is the weight of a ship’s boat and its contents if it displaces
250 cubic feet of fresh water?
Ans. —6*93 tons.
8. In what proportion does the pressure of water increase with
the depth?
9. A flat plate measuring 6 ft. X10 ft. is suspended horizontally at a
depth ot 20 feet, what pressure is exerted on its surface ?
Ans. —76,800 lbs.
10. Will a ship filled with water sink to the bottom?
11. The sea-cock of a double bottom tank is left open, the waterline
is 10 feet above the top of the tank, the area of which is 1500 square feet.
What is the total upward pressure on the tank top?
Ans .—428*5 tons.
12. How are water ballast tanks tested?
13. Describe the principle of the atmospheric sounding tube in
determining the depth of water.
14. If the volume of air in a tube is reduced to 2 inches on reaching
the bottom, what is the corresponding depth in fathoms?
Ans .—60£ fathoms.
15. Name the Authorities who assign load lines to British ships.
16. Sketch and describe fully the International Load Lines on a
ship’s side.
17. What do the following letters mean, LR, BC , BT } S, W ,
WNA, T> Ft
18. Give the lengths of the various lines and.their breadth, also the
diameter of the disc.
19. What special significance is attached to each of the load lines?
20. What load lines are marked on the sides of sailing vessels?
21. How could you tell on looking at a ship’s side whether her
marks were for ordinary cargoes or for timber deck load?
22. To which edge of the load marks is a ship submerged?
23. How could you tell how much deeper the T S mark may be
submerged when loading in freoh water?
24. What is meant by “Zones” and “Seasonal Areas?”
25. What compulsory marks, other than load lines, are shown on a
ship, and where?
questions
385
26. What is the penalty for not complying with the Regulations
regarding statutory marking?
27. Define the following terms (a) Under Deck Tonnage, (h) Gross
Tonnage, (c) Net Tonnage, (d) Displacement Tonnage, (e) Deadweight
Tonnage, (/) Freeboard, (g) Load Waterline.
28. What is meant by “Coefficient of Fineness”?
29. How may a hydrometer be used in conjunction with the loading
of a ship?
30. A ship’s draught in fresh water is 20 feet, what will her draught
be in salt water?
Ans .— 19 feet 6 inches.
31. The distance between the F and S marks is 7 inches, how much
may the T S mark be submerged in water of density 1007?
Ans. —5 inches.
32. Given the lengths npt discoloured in the tubes of three successive
soundings to be (i) 8 inches, (ii) ,12 inches, (iii) 2 inches, required the
respective depths.
n fathoms, (ii) 5*5 fathoms, (iii) 60*5 fathoms.
CHAPTER XTI
CARGO.
The primary purpose of a merchant ship is to carry cargo. The
British Merchant Navy is comprised of approximately 11,000 vessels,
of over 100 tons burden excluding fishing craft, aggregating 22 million
tons burden. They convey annually millions of tons of raw material and
manufactured goods between home and foreign ports. The handling
of that raw material, the skill and labour of manufacturing it into
desirable commodities and the transporting of the finished products
to all parts of the world form the basis of the livelihood and the wealth
of the British nation.
The shipowner’s responsibility for the cargo carried in a ship begins
when it is delivered alongside the vessel and ends when it is landed
from the vessel at her destination. The officer’s duty is to take all the
precautions dictated by prudence and experience to protect the goods
during the time they are in contact with the ship so that they may be
delivered in good order and condition.
CARGO GEAR.
Cargoes are handled by stevedores employed by the shipowner.
The officers supervise the work and are held responsible for the satis¬
factory completion of the job. The gear used depends upon the nature
of the goods and consists of Slings, Snotters, Nets, Trays, Can Hooks
and' Bull Ropes, in addition, of course to the lifting gear of Derricks,
Falls, Winches, etc.
Slings are made of 3-inch to 4£-inch manila rope, 5 to 8 fathcms
being cut from a coil and the ends joined by a short splice. When
splicing, two tucks of the whole strands should be given each way,
then halve each strand and tuck again, but don’t cut the ends of the
strands close to the rope as the splice will draw a bit at first when the
load is on.
Snotters may be either of rope or wire, 2 to 4 fathoms in length,
38G .
CARGO GEAR
387
with an eye spliced in each end. The middle of the rope is passed under
the package, one end is rove through the eye at the other end and
placed on the hook of the derrick fall The weight tightens the snotter
round the package.
Nets are suitable for small packages, bags, etc.
Strong Wooden Trays are used for lifting a number of small articles
such as drums of paints, and oil, cases containing bottles, candles and
other packages that can be lifted conveniently by one man and placed
on the tray. The trays are constructed to lift a load up to 1J tons and
are slung with a four-legged bridle.
The Bridle is made of four legs of equal lengths of either rope ot
wire, one end of each leg being spliced into an iron ring, the other end
into the eye of a hook, one hook for each of the eyebolts at the corners
of the tray. The derrick fall is hooked on to the ring and the tray
of goods hoisted.
Can Hooks are used for lifting casks but not, as a rule, when they
contain liquid. The sling of the can hook may be of rope or chain.
The hooks catch under the chime of the cask, and the heavier the weight
the better they grip.
Chain Slings have a hook at one end and a big link at the other end.
They are used to sling heavy coarse goods such as iron bars, sheet
iron, structural and agricultural materials. The chain is passed round
the material once, or twice if need be, and the end hooked round the
chain. The derrick fall is hooked on to the big link and the weight
tightens the turns of chain around the load.
Bull Ropes are used in the holds when goods have to be dragged
from the ends or sides of cargo spaces into the square of the hatch before
hoisting. One end is made fast to a pillar or some secure foundation,
the other end being passed round the derrick fall then back to the
pillar, around which a turn is taken, leaving the bight of the bull rope
slack enough to keep the fall from rasping on the underside of the hatch
coaming and to drag the sling of goods more or less horizontally to the
hatchway. The end of the bull rope is then let go and the goods hoisted.
Incidentally, it may be remarked that “bull rope” is the name
given by seamen to any length of rope which is used to prevent something
from chafing or grinding, as, for example, a rope attached to a mooring
buoy .ana led up through the end of an outrigger to keep the buoy
from bumping against the ship’s stem and bow plating.
Most ships are well provided with derricks and winches tor the rapid
388 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
transfer of cargo, as tlie time spent m port is an unprofitable period.
The port speed has to be averaged with the sea speed of the ship when
reckoning up the time taken to complete a voyage. The more round
voyages a ship makes in a year on a given route the more profitable
will the venture be, heqce the desire for quick dispatch.
Fig. 1.—A “Jumbo'* Derrick lifting 140 tons.
“Stand from Under."
The illustrations, -pages 50 and 55 indicate the usual arrangement
of derricks and winches. The average foreign-going cargo ship has
at least two derricks and winches at e^ch hatch capable of lifting 5
tons, and ait No. 2 and No. 4 hatches an additional derrick tested to
lift 20 tons, having its heel stepped on deck, the locality bemg strength¬
ened by thickening the deck plating and the adjacent parts so as to
CABGO GEAP.
389
distribute the thrust of the derrick to the neighbouring members of
the ship’s structure
The derricks are fitted with spans, either of single chain or a wire
purchase, the latter being more popular as the derrick can be easily
upended to any desired angle; also with two guys consisting of wire
pennants with rope purchases on their ends. The big derrick
is ngged m the same way but with heavier gear and triple or quadruple
lifting purchase and span. When lifting a heavy weight the mast
must be stiffened with preventer backstays
The illustrations, pages 45 and 46, show a Mannesmann tube derrick
being tested with a load of 42 tons on the ss. Clan Macartkur. A few
ships employed in special trades where heavy machinery may occasion*
ally be carried are fitted with gear to lift loads exceeding 100 ions.
The Factory and Workshops Act insists upon all chains, hooks,
swivels, shackles and derricks bemg tested and examined periodically.
When they are passed by H.M. Inspector of Factories, a Registered
Certificate of Test and Examination is issued and kept on hoard the
ship. All gangways, hatch and deck openmgs should be guarded,
when possible, against the possibility of persons inadvertently stumbling,
particularly during a temporary stoppage of cargo work. Apart from
the hurt to individuals arising from an accident, it is well to remember
that the Employers’ Liability and Workmen’s Compensation Acts
are comprehensive and far reaching, and it is the duty of officers as
the responsible representatives of their employers to see that all pre¬
cautions are taken to ensure that everything in connection with the
handling of cargo is satisfactory and reasonably safe.
The cargo gear should be overhauled at sea, when Gins, Runners,
Shackles, Guy Falls, etc., should be examined and refitted if required.
Goosenecks of derricks should be lifted and greased occasionally. When
the loading of a hold is completed the hatches are put on, covered with
tarpaulins and battened down securely. Derricks are lowered into
their crutches and lashed down. If the ship is proceeding on a long
passage the gear is unrove and stowed away in its appointed place.
Provision is made in some ships to stow the gear in a compartment
within the coamings of the hatch; in others, where the heels of the
derricks are mounted on a table, or tabernacle, built round the mast,
the enclosed space is utilised as storage accommodation.
Derricks are rigged and made ready for cargo work when entering
the port and, if possible, before the ship reaches her berth in readiness
390
NICHOLLS S SEAMANSHIP AND NAUTICAL KNOWLEDGE
for discharging. Hatches, however, should not be touched when the
cargo is a valuable one until they have been surveyed, and this is usually
done if heavy weather has been experienced? and there is a possibility
of damage to the cargo.
The Union Purchase or “married gear” is a favourite arrangement
for loading and discharging. It consists of two derricks, both fixed,
one guyed to plumb the hatch, the other to plumb overside. The
falls from both derricks are shackled to the same cargo hook. The
sling of goods m the hold is hooked on and hove up with the midship
fall until it is clear of the hatch coaming The slack of the fall from the
other dernck is then run in quickly and the midship fail eased ofi until
the load is wholly borne by the overside derrick and lowered into a
lighter or. on to a quay. The cargo hook is then hove back again to
take the next sling.
This method, for speedy work, requires two quick acting, reliable
winches and operators. It is suitable for light loads of about 5 to 10
cwt. per sling, but the extra strain imposed on the falls and guys as a
result of the cross pull is a disadvantage.
Swinging Dernck.—When there are no obstructions in its way a
swinging derrick having a long reach is, perhaps, the speediest and most
reliable arrangement for working heavy slings of bag cargo up to a
ton and a half in weight, especially if it be fitted with an adjustable
span so that it may be regulated to plumb the hatch and also overside.
It can pick up and land the goods anywhere within the radius of its
swing, thus accelerating the work of handling the goods and making up
the sets for slinging.
► The outboard guy, when discharging cargo, is usually led to a
steam winch and the light derrick is sometimes pulled inboard by
leading the guy through a block aloft and securing a heavy weight,
a “dead man,” on the end of it. There may be a prejudice against the
“dead man” method of controlling the inward swing owing to the danger
of someone getting hurt by the descending weight.
The Double Lift method is sometimes used for the rapid handling
of mixed general cargo, viz., one derrick lifting ofi the quay and landing
on deck, and another dernck picking ofi the deck and lowering into
the hold, using skidboards where required.
More men are required per stevedore gang for the double handling,
but rope whips substituted for wire falls and worked on the winch ends
make for increased speed which may offset the increased labour cost.
DUNNAGE
391
The working of derricks is, however, the middle operation when
loading or discharging There is the labour of making up the sets ox
slings to feed them, also the distribution of the goods when landed,
either in the ship’s hold when loading, or into a lighter, or on the quay,
when discharging. The three operations of slinging, transporting,
delivering, should be organised to time in with each other as closely
as circumstances and the human element will admit.
Winches —The engme-room staff attend to the overhaul of winches,
windlass, steering gear and other deck machinery. The deck staff,
however, are called upon to work them and they should, at least, be
able to pack the glands at the ends of the cylinders steamtight, as
they may give out when working cargo and a mechanic not available.
The job is a simple one.
Care should he taken before starting a winch to open the cocks in
the cylinders to drain off any water that may be lodging in them.
The steam should be turned on gently at first, especially if the winch
has been standing idle for some time and this is particularly necessary
in cold or frosty weather. When frost is severe the winches not in
use are sometimes kept turning slowly out of gear to prevent the steam
pipes from cooling off and freezing up.
DUNNAGE.
Most vessels have permanent dunnage or ceiling covering the tank
tops consisting of 3-inch planking resting on bearers about 2 inches
deep, which form an air space between the tank top and the ceiling to
dry up moisture.
Portable Side Battens consisting of boards about 6 inches broad and
2 inches thick, spaced about 9 inches apart, are fitted into cleats on the
side framing of the ship; the battens may be arranged horizontally or
vertically and sometimes diagonally. Stokehold Bulkheads are usually
fitted with battens and other bulkheads also. This permanent dunnage
is usually sufficient for rough cargoes and for goods that are not liable
to absorb moisture.
Additional Dunnage should, nevertheless, be laid at the bilges where
water is likely to accumulate, also on stringers and stringer plates
where moisture from condensation or otherwise may tncMe down
the shell plating and framework of the ship and lodge on the stringer.
Matting should always be laid on the ceiling for bale goods and bag
cargoes, and if the nature of the cargo is likely to draw moisture an
392 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
additional 2 or 3 inches of dunnage should be laid on the ceiling and at
the turn of the bilges.
The Dunnage Wood is of various lengths and thicknesses, and it
should be kept clean and dry, as many cargoes, especially foodstuffs
in bags, generate heat and absorb moisture, dirt and oil stains from
dirty dunnage wood.
Regulations regarding the dunnaging, stowing and ventilating of
particular cargoes are enforced at some ports, particularly for rice
and grain, and the conditions of loading them must be complied with.
HOMOGENEOUS CARGOES
Coal as a homogeneous cargo ranks first in importance as it is the
only mineral product the United Kingdom possesses in excess of home
requirements, the normal export being about 60 million tons per annum,
and, in addition, some 16 million tons are delivered at coaling stations
abroad for bunkering ships. It is still the engineer’s chief source of
energy.
Coal is shipped from ports in the Bristol Channel, North East
Coast of England, Firths of Forth and Clyde, and abroad from New¬
castle (N.S.W.), Pennsylvania, (U S.A.), Natal, Calcutta and Shanghai.
This cargo is loaded usually alongside specially constructed “tips,”
the coal being tipped out of the railway waggon into a shute leading
into the ship’s hold At some ports the waggon is lifted bodily with a
crane, swung over the hatchway and emptied into the hold. The
discharge is usually by tubs filled in the hold, hoisted up and swung
outboard on to the quay or into lighters alongside, although elevator
conveyancers working on the principle of a bucket dredger are available
at some ports. At other places mechanical grabs are used. The
grab is lowered from the end of a crane into the hatchway, closes its
“jaws” on a few tons of coal and is then hoisted up and emptied into
waggons or lighters Specially constructed colliers making short
voyages have been built for this particular trade, the features being
large hatchways and self-trimming holds.
Surface Ventilation is essential with„a coal cargo as the gas is lighter
than air and must be given an opportunity of escaping upwards through
the ventilators and a hatch should be left ofi in fine weather. Through
ventilation is to be avoided as a current of air passing through the
mass of coal might stimulate into activity any dormant gases into
spontaneous combustion.
HOMOGENEOUS CARGOES
393
It is recommended that colliers and vessels carrying coal on long
passages should unship the side dunnage battens and so remove this
avoidable source of providing air pockets and the supply of oxygen
necessary for combustion.
All kinds of coal, even anthracite, are liable to spontaneous heating
and combustion, though some are more dangerous than others
All coal gives off inflammable gas when freshly worked or when
freshly broken, and the gas becomes explosive when mixed with certain
proportions of air 9
Heating of coal does not proceed from the presence of gas, but is
caused by the absorption of oxygen from the air
This absorption and the accompanying development of heat is
greater at high than at low temperatures, so that when once commenced
it proceeds at an increasing rate if the supply of air is maintained.
Danger of over heatmg and spontaneous combustion increases with
the length of time the coal remains m the ship, 77° Fahr. being a
critical temperature.
There is no risk entailed by coal being wet when taken on board
It is not in any way more dangerous to carry than coal which is
perfectly dry.
When loading a cargo of coal the dunnage wood is stowed at the
ends of the holds and covered up to keep it clean and clear of the coal.
The first few tons of coal are lowered into the hold, instead of being
dropped from a height, and some planks laid over the ceiling in the
square of the hatch. Provision is made so that when loaded the temper¬
ature of the cargo below the surface can be taken in different parts of the
hold. The trimming of the cargo should also be carefully superintended
and an efficient system of surface ventilation maintained.
Ores.—Iron, manganese, copper and other ores are also carried in
bulk, but owing to the heavy nature of such cargoes a great amount
HOMOGENEOUS CARGOES
393
It is recommended that colliers and vessels carrying coal on long
passages should unship the side dunnage battens and so remove this
avoidable source of providing air pockets and the supply of oxygen
necessary for combustion.
All kmds of coal, even anthracite, are liable to spontaneous heating
and combustion, though some are more dangerous than others
All coal gives off inflammable gas when freshly worked or when
freshly broken, and the gas becomes explosive when mixed with certain
proportions of air *
Heating of coal does not proceed from the presence of gas, but is
caused by the absorption of oxygen from the air
This absorption and the accompanying development of heat is
greater at high than at low temperatures, so that when once commenced
it proceeds at an increasing rate if the supply of air is maintained.
Danger of over heating and spontaneous combustion increases with
the length of time the coal remains m the ship, 77° Fahr. being a
critical temperature.
There is no risk entailed by coal being wet when taken on board
It is not in any way more dangerous to carry than coal which is
perfectly dry.
When loading a cargo of coal the dunnage wood is stowed at the
ends of the holds and covered up to keep it clean and clear of the coal.
The first few tons of coal are lowered into the hold, instead of being
dropped from a height, and some planks laid over the ceiling in the
square of the hatch. Provision is made so that when loaded the temper¬
ature of the cargo below the surface can be taken in different parts of the
hold. The trimming of the cargo should also be carefully superintended
and an efficient system of surface ventilation maintained.
Ores.—Iron, manganese, copper and other ores are also carried in
bulk, but owing to the heavy nature of such cargoes a great amount
394
NXCIIOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
of space is left in the holds when the ship is down to her load line
weight is unavoidably concentrated over a small area of the
thus causing excessive strains locally. (See Fig. 9, page 430 )
ships are, therefore, specially strengthened and designed for this
A transverse section of a special ore ship is shown in the lllusti
Ores are loaded and discharged as in the case of coal, according
custom of the port
Grain.—The principal grain ports are Montreal, New York,
adelphia, San Francisco, Vancouver and ports in the River Plate
tralia and New Zealand. Rice is also classed as gram and is loac
bags at ports m the Far East, the chief being Calcutta, Rar
Bassein, Saigon and Bangkok.
TRUNK
Fig. 3.—Section of a Grain Carrier.
. Grain when carried in bulk is very liable to shift, the angle of 3
of a pile of gram being about 25 degrees, so that the rolling of a s
sea is capable of setting it in motion. Certain statutory regul
must be complied with, under heavy penalties for evasion, by t
in the North American, Mediterranean and Black Sea gram t
the rules being contained in a “Memorandum on Grain Cargoes”
by the Board of Trade.
Special types of ships have been built for the carriage of bulk
called trunk ships. Grain is pumped into the ship through a
canvas hose until the lower hold and the trunkway are comj
filled. The grain settles down from the effect of tie ship’s mot
sea, but the grain in the narrow trunkway acts as a feeder and
the hold quite full. Grain seeks into every hole and comer, so the
snace must be made graintight by caulking the open seams betwe<
planks of the ceiling or by nailing thin nairow strips of wood ov
seams. When a ship, not specially built for the purpose, is requi
GRAIN AND RICE
395
load a cargo of gram m bulk a temporary midship longitudinal bulkhead
must be constructed, extending from one end of the hold to the other
and from the bottom up to the deck The bulkhead is made of deal
planks laid fore and aft, edge on edge, so that it forms a boarded parti¬
tion dividing the hold longitudinally into two parts. Some ships have
the midship pillars staggered on alternate frames so that the planks
may be rove between them.
Ships engaged frequently in the bulk grain trade have steel midship
longitudinal bulkheads in the lower hold.
A temporary box-shaped feeder must be built in the hatchway;
it is also made of deals standing on their ends and reaching from the
’tween deck to the mam deck hatch coamings, the whole bemg tomed
off from the ship’s side, or braced together with wire stays, and backed
up with grain in bags to keep the box feeder firmly in position. The
cubic capacity of a feeder should be large enough to contain from 2 to
6 per cent, of the quantity of gram in the cargo space it is designed to
feed.
The grain is pumped out of the ship by elevators and stored in
specially constructed granaries at those ports which specialise in its
storage, so that it is not touched by hand at all.
Riee is an expensive cargo to carry as the holds have to be fitted up
with an elaborate system of ventilation on the principle of a drainage
scheme, so that air may pass freely throughout the whole cargo. The
ventilators are box-shaped and made of two planks of wood kept about
8 inches distance apart by pieces of wood They are laid fore and
aft on top of a tier of bags from bulkhead to bulkhead and also athwarfc-
ships from side to side. These fore-and-aft and cross ventilators are
laid horizontally on a tier of bags and spaced five bags apart, and they
communicate with a series of vertical vents extending from the ceiling
to the top deck. This horizontal system is laid at every third tier
of bags. In addition to all this the side battens and bulkheads are
covered with sticks or bamboos tied criss-cross or lattice fashion and
all bare iron and dunnage is covered with rush mats.
The purpose aimed at is to secure a current of air through the cargo
to carry away the carbonic acid gas given off by the rice and also to beep
the hold from sweating. An air space is left between the top tier of
bags and the underside of the deck and also round the inside of the
hatch coamings. During the latter part of the rice season when the
396
NICHOLLS’S SEAMANSHIP AND NAUHCAL KNOWLEDGE
grain is more matured the ventilation is reduced a little. The cargo
is loaded under the supervision of official surveyors.
In Figure 4, A indicates the fore-and-aft ventilators, B the athwartship
ventilators, C the five bag spacing of ventilators. The arrows indicate
the air current flowing to the vertical ventilators shown heavy.
STOWAGE OF CARGOES.
Merchant vessels bxist primarily for the carriage of cargo or pass¬
engers. With respect to cargo the aim of those on board should be
to prevent damage or deterioration whilst it is under their care and
to- deliver it, as far as possible, in as good condition and order as it was
when received.
Receiving Cargo.-—When about to take in any cargo, if you have
not been with similar cargoes before, you should ascertain as much as
you can as to its nature and what precautions are necessary with
respect to it.
Evidently it is necessary to note particularly the order and condition
of cargo when first received, and not to give a clean receipt for it unless
its condition warrants it, otherwise the ship may be held responsible
for loss or damage which it may have received prior to being shipped.
CARGO STOWAGE
397
Stowing the Cargo.—In the stowage the first consideration must
be given to safety, \.e. % the cargo must be stowed so that'the ship will be
stable and seaworthy, and it must be secured in such a manner that it
cannot shift if the vessel encounters bad weather.
Then care must be taken to stow it so that it will not be damaged
either by contact with, or proximity to, other kinds of cargo which
would injuriously affect it, or from water which may find its way into the
interior of the vessel, or from the sweating of ironwork, etc. Care must
also be taken to prevent it being pilfered or damaged whilst being stowed.
Where cargo is being shipped for several ports, arrange it so that you
can conveniently discharge it at each port in rotation in the order you
visit them, so that none shall be over carried.
Deck Cargoes.—The mate's receipts and bills of lading should be
signed ik at shippers 5 lisk' 5 ; this, however, does not exempt the ship from
claims arising from damage due to carelessness in stowing and securing
the deck cargo. Dangerous goods on deck, such as oils, acids, and
chemicals, should be in packages convenient for handling in case they
have to be jettisoned. Gases expand with heat and their containers
should be protected from the rays of the sun. Steering gear, boats, and
sounding pipes should be accessible; properly protected gangways fore
and aft should be provided for the crew.
Very heavy goods to be stowed over bulkheads and the beams
shored up from below. Dunnage to be laid diagonally on deck to avoid
buckling of plates. ^ Everything to be well lashed down. Deck cargo
of an inflammable or corrosive nature not to be stowed on deck over a
hold in which explosives are carried.
With regard to the stowage of mixed cargoes apart from ensuring
that the hold is well ventilated, that the packages are properly dunnaged
on a level foundation, well secured and not likely to be damaged by
chafing and the heaviness of overstowed cargo, is to protect food¬
stuffs from being tainted by the fumes of odorous goods. Eggs and
flour, for example, are easily tainted if stowed over apples, onions,
copra, new sawn timber, petroleum, etc.; they should be stowed in a
separate compartment if possible.
Rolls of paper are stowed on end; glass, slabs of marble and galvan¬
ised iron on their edges. Copra contains oil, it is easily ignited and should
be stowed away from boiler space and from taintable *foods. When
loading cotton and wool in bales fire hoses should be connected, barrels
of water at hatchways and buckets handy, no smoking, spark arresters
on funnels and ventilators.
398 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
QUESTIONS AND ANSWERS.
I How would you get a hold ready for cargo after discharging coal?
Sweep the sides, bulkheads and ceiling down thoroughly, send the
sweepings up out of the hold.
If the weather is suitable and there is time for drying purposes,
rig the hose and wash well down. If not, sprinkle damp sawdust and
sweep up clean Lift the limber boards and clean out the bilges. Give
them a coat of cement wash. See that the rose boxes are all clear.
Replace limber boards and dunnage the hold If the cargo is to be
gram in bags or anything which requires special protection, cover all
bare iron with battens, j burlap, or mats. Rig shifting boards if necessary.
2. If you were stationed in the hold to look after the interests of the
ship during the loading of a general cargo, what would you
consider it your duty to do?
I would inspect the cases or packages as they came on board, and
if any appeared to be damaged, notify the chief officer at once before
he gives a receipt for it. I would see that any directions printed on
any package were observed whilst being stowed, such as “This side to
be stowed uppermost,” or “Stow away from the boilers,” or that hooks
were not to be used for bale goods, etc. I would particularly guard
against broaching or stealing of any cargo, and see that all was properly
stowed and blocked off securely Should not stow liquids above
solids if it is possible to avoid doing so.
3. What would you look out for in the hold whilst discharging?
As before, I would prevent any broaching, and see that no cargo
was damaged by rough or improper handling. If any cargo appeared
to be damaged. I would call attention to it before disturbing it, so that,
if necessary, it may be surveyed.
4. If a vessel has ’tween decks, would they require dunnaging?
Yes; sufficient to keep the cargo clear of the deck, an inch or so for
cases, and a little more for bales or bags. I would lay it athwartships,
so that in case of leakage the water might drain freely to the scuppers.
5. What special precautions would you take if you were going to load
grain in bags for a long passage?
1 would line the hold out with boards, and cover them with old
sails, burlap, bagging, or * **ould also cover up all bare iron likely
CARGO STOWAGE
399
to come m contact with the cargo, such as stanchions, masts, etc,, and
lash good shifting boards on both sides of the stanchions amidships f
so as to form a fore-and-aft bulkhead, to prevent the cargo shifting.
6 If you were going to load a cargo of raw sugar or molasses, what
would you be careful about in dunnaging the hold?
To leave a free course for the drainage to run to the pump well.
7. Where would you stow bags of sheep dip, or patent manures, or any
other strong smelling cargo?
Where it would not be possible for it to cause damage to other
cargo by reason of the strong odour which it emits. Tea, for instance,
is very liable to absorb any foreign smell; I should see therefore if
any was to go in the ship that it was stowed in a different hold. The
same precautions would apply to any foodstuffs such as grain, flour, etc.
8 In loading a mixed cargo, how should it be generally distributed
m the hold?
The deadweight or heaviest portions of the cargo amidships in
the main hold; liquids, if any, in the ends at the bottom; bales, cases, etc.,
in the ’tween decks or upper part of lower hold.
9. How should railway iron or tram lines be stowed?
Fore and aft solid, bases alternately up and down, this form of
stowage generally being termed “locked together.”
Tank tops must be protected with heavy planks laid athwartships.
Soft wood battens or old ropes or strands of an old hawser should
be laid athwartships between each tier to soften the whole mass and
help to bind it together.
Pillars in the hold should have wooden battens placed between them
and the rails. Good heavy pieces of timber should be placed vertically
at the ship’s side, and the whole mass wedged up tight.
The loading should be so arranged that when all is stowed a level
surface is presented right across the hold. Athwartship planks should
be laid on top of the rails, and the hold filled up with other cargo solidly
stowed. If the hold cannot be filled, the iron must be securely “tommed
down” from the deck beams above it.
A full cargo of railway iron should be stowed locked together solid
at the bottom, and diagonally or grating fashion afterwards.
Wooden battens or old ropes or strands of old hawsers should always
be laid athwartships between each tier of rails.
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
400
The sides of the ship must be protected by rails locked togethei
fore and aft and held in position by good baulks of timber placed vertically
against them, the whole being wedged up tight.
The upper tiers should be laid solid fore-and-aft with good heavy
planks placed athwartships on top of them, and well “tommed down”
from the deck beams above them.
Good chain lashings should be used at the ends of each hold to
prevent any movement or working of the iron when tbc ship dives into
a head sea.
About a third of the weight should be carried in the ’tween decks.
Too much weight must not be placed at the extreme ends of the
vessel.
It would be necessary to examine the “toms” and chain lashings
frequently during the passage as they are likely to work loose. Should
they do so they must, of course, be tightly wedged up again.
10. How would you stow a ground tier of casks or barrels?
I would stow each barrel fore and aft on two good beds of sufficient
thickness to keep the bilge clear of the floor, and put quoins under
each quarter. When stowing alongside the keelson, I would' keep the
bilge clear of it by putting stout pieces of wood, upright or vertical,
between each quarter and the keelson. I would see that when stowed
the bung was on top, and be careful to keep the tier strictly leveL
After stowing the *wing barrels, I would fill up any space left with
dunnage in order to secure the cargo.
11; How would you stow the riding tiers?
In the cantlines of the lower tier, each barrel lying on the quarters
of four barrels below it.
12. How would you stow a ground tier of barrels containing dry goods,
such as cement, flour, etc.?
f
I would dunnage the floor and then stow the barrels fore and aft,
resting evenly on the dunnage. When placing them I would see that the
pieces of wood forming the head were vertical, so as not to be so liable
to split with the weight of the riding tiers.
Note .—Barrels containing liquids are made so that the grain of the
wood in the head is in a line with the bung, so that when stowed bung
up the head pieces are vertical.
CARGO STOWAGE
401
13. How would you stow barrels of tar, pitch, etc.?
The sides of these barrels being straight I would not use beds, but
stow them fore and aft flat on the dunnage, bung up.
14. How many hoops are fitted on a good cask?
Bight: bilge, quarter, and two chime hoops at each end. The
rivets of the hoops are in bne with the bung.
15 How many heights of barrels, hogsheads, puncheons and
are you allowed to stow?
Eight of barrels, six of hogsheads, four of puncheons, and
of pipes.
16 Why should the number be limited?
Because the lower tier, having to bear the weight of all above it,
m ight be damaged if too many heights were stowed
17 Where and how would you stow wines and spirits?
Where they are least likely to be pilfered by crew or cargo workers.
Should see that cases were all well blocked up, and that casks Y ere
carefully stowed bung up and bilge'free, and well quoined and secured.
15. How would you stow bale goods of manufactured materials, etc.?
On their flats, with mark and number uppermost. Wing bales on
their edges, mark and number inboard.
19. How would you stow cases of glass, slabs of marble or grindstones?
On their edges; as they would then be less likely to get broken.
Large cases of plate glass are best stowed athwartships.
20. Suppose you were loading grain, and a compartment in the lower
hold was to be stowed partly in bulk and partly in bags, how
would you stow it?
No more than three-fourths is allowed to be in bulk. I would take
that in first and level it off, then cover it over with mats and boards
and stow the bags on top. Fore-and-aft boards must be not more
than 4 feet apart. Athwartship ones not more than 9 inches apart.
The athwartship ones must be on top of the fore-and-aft ones.
21. How would you separate different shipments of bar or rod iron?
If only two lots I would stow in different sides if possible, or otherwise
by laying a piece of spunyaro across each lot before placing the next
pipes
three
402 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
on top of it. Knots can be tied id the spunyarn, or tallies tied on,
to indicate which lot is beneath it and a corresponding note made in
the cargo book.
22. What precautions must be observed when taking in gunpowder?
A magazine must previously be constructed in a suitable place
in the ’tween decks, and, when receiving it on board, all fires must be
put out until it is stowed and secured. Any electric wiring passing
through the compartment must be disconnected. The dag B must be
hoisted
23. Where must dangerous liquids be stowed, such as aquafortis,
vitriol, etc.
In the most suitable place on deck, as in case of leakage it may be
necessary to jettison all or part of it. It should be well secured and
covered with tarpaulins or canvas.
24. What precautions must be observed at sea when carrying coal
cargoes?
To keep the surface well ventilated by taking off some of the hatches
when the weather permits, and keeping ventilators open. Also, the
temperature in different parts of the hold should be tested daily and
entered in the log; if it exceeds 77° Fahr. there is risk of the coal
being on fire.
25. How many tarpaulins would you put on your hatches?
Two good ones with an additional older one on top.
26. How are they secured?
By turning the edges inwards and jamming them hard up against
the hatch coamings by means of hatch bars and wooden wedges. Iron
cleats axe fitted to the hatch coamings for this purpose.
27. What makes a hatch coaming watertight?
It has an angle iron riveted to it and to the deck all round the hatch.
This is made watertight by caulking at the time the ship is built.
28. What is the use of camber on the deck?
To give it additional strength and enable it to be quickly cleared
of water.
29. How would you parbuckle a cask out of a tier?
Take the bight of a rope and pass its two parts one under each
CARGO STOWAGE
403
quarter of the cask. Bring them up over the quarter of the next
cask, carry them along the tier and make them fast round the quarters
of another cask in the same tier, or to the ship’s side. Haul away on the
bight.
30. How do you sling a cask head up?
By standing the cask on the bight of the sling and forming a half
hitch over the head of the cask with each part of the sling.
31. What arrangement or disposition of the cargo has a tendency to
make a vessel “stiff”; and also to make a vessel “tender”?
Stowing all the heaviest weights in the bottom, and keeping as
much cargo as possible in the lower hold, will have the effect of making
a vessel “stiff.” By raising the weights, and putting more cargo in the
’tween decks, she will be made more “tender.”
Deck cargo tends to make a ship very tender or unstable.
32. What difference then should be made between the stowage of a
cargo in a “stiff” vessel and the stowage of a similar cargo in a
“tender” vessel?
The “stiff” vessel should have the heavier parts of the cargo raised
more than the “tender” vessel; also when there are ’tween decks a
greater proportion of the cargo should be stowed there.
33. What will be the result of winging out weights, i.e. } of stowing
heavy kinds of cargo in the wings?
It tends to make the vessel steadier in a seaway, and she will roll
less quickly.
34. What will be the result (i) if heavy weights are stowed at the ends
of a vessel; (ii) if the heavy weights are concentrated towards the
middle?
In the first case the ship will be liable te pitch heavily, and ship
heavy seas at the bow or stem; she will also he subjected to severe
straining in a seaway. In the second case the bow and stern will rise
more easily to the force of the sea, and she will not be so liable to ship
seas over the how and stem.* Too much weight in the middle would
also strain the vessel severely in a seaway.
A vessel that is very full at the bow and stem should have more
cargo towards the ends than a vessel fine at the bow and stem.
♦Weights at the end have also a lateral effect in making the ship slower in
answering the helm.
404 NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
35. What is meant by a homogeneous cargo*
A cargo which is all of one kind, such as a complete cargo of grain,
coal, etc.
36. What are the mate’s duties generally, in relation to the taking
in or discharging of cargo?
The mate usually gives the receipts for cargo when it is received
on board, and it is important that these should correctly specify the
quantity and condition. He should see that a correct account or
tally of the cargo is taken on the ship’s behalf, and that its apparent
order and condition when received is duly noted. He should also see
that any instructions of the master relative to the stowing of the cargo
are duly earned out, and that when the cargo is a miscellaneous one
a record of the position which each part of the cargo occupies m the
hold is kept in the cargo book.
In the case of a dispute arising with respect to the tally, and it is
not possible to rectify it at the time, a note explaining the circumstances
should be made on the receipt.
37. Should cargo come on board in a bad or damaged condition, whafc
would you do?
Point the matter out to the shipper’s representatives so that if
possible they may have it put right. Otherwise, give a receipt for it in
accordance with the facts. If not satisfied I should refuse to accept it.
38. You have nearly finished loading. Your ship has a list. How
can you tell whether she is down to her marks or not?
Drop a plumb bob over each side of the ship and measure the distance
between the upper edge of the deck line and the surface of the water.
Find the mean of these two measurements which will be your freeboard
at the time. Compare this with the freeboard certificate.
39. How would you stow a Heavy mineral cargo, such as manganese
ore?
Except in a ship specially designed for the trade, such as a “side
tank” or “wing tank” vessel, I should carry about one-third of it in the
’tween decks to moderate the stability.
Should not have too much weight in the ends of the ship, number
one hatch being trimmed aft, and the after hatch trimmed forward.
In the other hatches the ore is generally left higher amidships
than in the wings. The slope must be a reasonable one on account
of the possibility of shifting if it was heaped up too much.
SPECIAL CARGOES
405
SPECIAL CARGOES
The Board of Trade issue “Regulations relating to the Carnage of
Dangerous Goods and Explosives' 5 and also of “Grain.' 5 Special
cargoes such as oil in barrels, cotton, grain, rice, deck loads, etc., are
loaded at various ports abroad under certain statutory conditions
agreed to by boards of underwriters, shippers and shipowners. We
shall indicate briefly some of the more outstanding of those regulations.
STOWAGE OF EXPLOSIVES AND OTHER DANGEROUS GOODS
By the Merchant Shipping Act every person who sends any dangerous
goods on board any vessel is required, under a heavy penalty, to mark
distinctly and fully on the outside of the package containing the same
the nature of the goods Also, he is required to give a written notice
to the master or owner, of the nature of the goods, together with the
name and address of the sender, either at or before the time of sending
the goods to be shipped.
By dangerous goods is meant aquafortis, vitriol, naphtha, benzine,
gunpowder, lucifer matches, nitro-glycerine, petroleum and other
explosives or goods of a dangerous nature.
The master or owner of a vessel may refuse to take on board any
package or parcel which he suspects to contain any dangerous goods, and
may require it to be opened to ascertain the fact.
If it is found that goods, which, in the judgment of the master are
of a dangerous nature, have been shipped without being marked as
required, or without the written notice having been given, the master
may cause such goods to be thrown overboard.
GENERAL PRECAUTIONS
Petroleum, paraffin, methylated spirits, naphtha, or any liquid or
substance liable, under certain conditions, to give off inflammable vapour,
should not be carried on ships which have explosives on board.
Mineral acids, ethers, compressed gases, matches, and other sub¬
stances or liquids liable to spontaneous combustion, or liable to cause
fire or explosion, if carried on a vessel with explosives, should be carried
on deck only, or if below deck should be in a hold separated by a bulk¬
head from that containing explosives, and kept as far away from it
as possible.
Explosives should always be separated by a bulkhead from any other
dangerous articles, and the compartment where explosives are stowed
406
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
should be kept locked to prevent unauthorised peisons having access
thereto.
AH magazines or partitioned-off spaces for explosives must be so
placed that their doors open out to a hatchway.
No iron of any sort to be used in their construction, and no fastenings
but copper nails.
Dynamite should be stowed m the most easily accessible part of
the hold, and proper precautions should be taken to keep it dry.
Drums of liquid ammonia should be stored in a part of the ship
away from, and beyond the influence of, any heat, remote from living
quarters, and as deck cargo only. They should be protected from the
rays of the sun, and should not be covered with a black tarpaulin.
Bi-sulphide of carbon, also known as carbon bi-sulphuret or di¬
sulphide of carbon, etc.—The vapour of this is easily ignited. The mere
striking together of two pieces of iron m an atmosphere impregnated
with it may cause ignition. It should be carried as deck cargo only,
away from all living quarters, and the utmost care must be taken to
protect it from the rays of the sun, or lights or sparks. Sail cloth,
but not tarpaulin, is suggested as a covering. Smoking in its vicinity
should be strictly prohibited. The cases containing the drums should
be examined at least twice a day during daylight, and if any leakage
is detected they should be thrown overboard immediately. Leakage
may be detected by the presence of a powerful odour.
Anti-fouling composition, anti-corrosive paints.—Certain of these
give off gases which, when mixed with air, are highly explosive. Care
should be taken that lights are not used in any compartment of a vessel
in which such goods are, or have recently been, stowed.
Petroleum spirit, benzoline, gasoline, petrol, lythene, etc., also give
off inflammable gas at all times, and in vessels carrying petroleum,
etc., special precautions should be taken against the use of lights of
any kind, also against smoking whilst the hatches are off or any deck
openings uncovered.
GRAIN
Bags.—Special precautions are taken with grain in bags for a long
passage. The British regulations require the hold to be divided by
amidship shifting boards extending from deck to deck in the lower
hold and 'tween decks, and the dunnage covered with mats.
Some countries do not insist on shifting boards and others only
408 NICHOLLS 5 S SEAMANSHIP AND NAUTICAL KNOWLEDGE
gram from shifting shall each be liable to a fine not* exceeding £300.
The owner is also liable to the same fine, unless he shows that he took all
reasonable means to enforce the proper loading of the grain and the
observance of the law and was not privy to the breach thereof.
The regulations regarding grain cargoes are not the same m all
Colonies and countries. The authorities in different ports make some¬
what different rules. These are generally approved by the Board
of Trade, and vessels loading in those ports must comply with them
unless they are loaded in accordance with the Eighteenth Schedule to
the Merchant Shipping Act, 1894.
OIL CARGOES.
The particular dangers connected with a cargo of petroleum spirit
are fire and explosion. Petroleum spirit gives off vapour freely at
ordinary temperatures, and this vapour will form hn explosive or
inflammable mixture with air, according to the proportions in which
it is present.
The bulkheads dividing the cargo holds from other spaces should
be perfectly tight.
Wooden barrels should not be used for the conveyance of petroleum
spirit below deck.
Special precautions should be taken against smoking and the use
of fire or light of any kind while the cargo is being loaded or unloaded.
Ventilation must be carefully 'attended to. Half the number of
ventilators should go to the bottom of the hold, the other half reaching
only a short distance down below the deck. The short ventilators
should be turned to windward and the long ones to leeward.
Petroleum spirit may be carried in wooden barrels or steel drums
on deck provided they are so stowed as not to interfere with the
navigation of the ship or to make the vessel unseaworthy.
Petroleum spirit is any liquid which is produced by distillation from
petroleum shale, or coal, and flashes at a temperature of less than 73° F.,
such as benzoline, gasoline, petrol, naphtha, benzol, benzine, lythene,
etc.
TIMBER DECK CARGOES.
The term “timber deck cargo” means a cargo of timber carried on an
uncovered part of a freeboard or superstructure deck. The term does
not include wood pulp or similar cargo—
ine Structure of the Ship is to be of sufficient strength for the deeper
SPECIAL CARGOES
409
draught allowed and for the weight of the deck cargo. She must have
superstructures consisting of a forecastle of at least standard height and
at least 7 per cent of the length of the ship, and, m addition, a poop,
or a raised quarter-deck with a strong steel hood or deckhouse fitted
aft.
Bulwarks.—The ship must be fitted either with permanent bulwarks
at least 3 feet 3 inches high, specially stiffened on the upper edge and
supported by strong bulwark stays attached to the deck in the way
of the beams and provided with necessary freeing ports, or with efficient
rails of the same height as the above and of specially strong construction.
Deck Openings.—Openings to spaces below the freeboard deck are
to be securely closed and battened down. All fittings, such as hatchway
beams, fore-and afters, and covers, are to be m place Where bold
ventilation is needed, the ventilators are to be efficiently protected.
Stowage.—The.wells on the freeboard deck are to be filled with
timber stowed as solidly as possible to at least the standard height of a
bridge.
On a ship within a seasonal winter zone in winter, the height of
the deck cargo above the freeboard deck is not to exceed one-third
of the extreme breadth of the ship.
All timber deck cargo is to* be compactly stowed, lashed and secured.
It must not interfere in any way with the navigation and necessary
work of the ship, or with the provision of a safe margin of stability
at all stages of the voyage, regard being given to additions of weight,
such as those due to absorption of water and to losses of weight such as
those due to consumption of fuel and stores.
Protection of Crew,—Safe and satisfactory access to the quarters
of the crew, to the machinery space and to all other parts used m the
necessary work of the ship, is to be available at all times. Deck cargo
in way of openings which give access to such parts is to be so stowed
that the openings can be properly closed and secured against the admis¬
sion of water. Efficient protection for the crew in the form of guard
rails or life lines, spaced not more than 1# inches apart vertically, is to
be provided on each side of the deck cargo to a height of at least 4 feet
above the cargo. The cargo is to be made sufficiently level for gangway
purposes.
Steering Arrangements,—Steering arrangements are to be effectively
protected from damage by cargo, and, as far as practicable, are to be
accessible. Efficient provision is to be made for steering in the event of
a breakdown in the main steering arrangements,
p
410 NICHOLLS’s SEAMANSHIP AND NAUTICAL KNOWLEDGE
Uprights.—Uprights when required by the nature of the timber
are to be of adequate strength and may be of wood or metal; the spacing
is to be suitable for the length and character of timber earned, but is
not to exceed 10 feet. Strong angles or metal sockets efficiently secured
to the stringer plate or equally efficient means are to be provided for
securing the uprights.
Lashings.—Timber deck cargo is to be efficiently secured throughout
its length by independent overall lashings spaced not more than 10
feet apart.
Eye-plates for these lashings are to be riveted to the sheer strake
at intervals of not more than 10 feet, the distance from an end bulkhead
of a superstructure to the first eye-plate being not more than 6 feet
6 inches. Additional eye-plates may be fitted on the stringer plate.
Overall lashings are to be in good condition and are to be not less
than f-inch close link chain or flexible wire rope of equivalent strength,
fitted with sliphooks and stretching screws, which are tty be Accessible
at all times. Wire rope lashings are to have a short length of long
link chain to permit the length of lashings to be regulated.
When timber is in lengths less than 12 feet, the spacing of the
lashings is to be reduced to suit the length of timber or other suitable
provision made.
When the spacing of the lashings is 5 feet or less, the size of the
lashing may be reduced, but not less than J-inch chain or equivalent
wire rope is to be used.
All fittings required for securing the lashings are to be of strength
corresponding to the strength of the lashings.
On superstructure decks, uprights, where fitted, are to be about
10 feet apart and are to be secured by athwartship lashings of ample
strength.
Plans showing the fittings and arrangements for stowing and securing
timber deck cargoes in compliance with the foregoing conditions and
regulations are to be submitted to the assigning authority.
FROZEN AND CHILLED CARGOES.
The hold insulation of modem “meat” ships usually consists of
broken up cork, the pieces averaging about the size of a pea. This is
tightly packed against the sides, bulkheads* deckheads, and floors or
ceilings of the spaces and held there by f-inch boarding, the whole
occupying a depth of about 9 inches. This entirely surrounds the
REFRIGERATOR CARGOES
411
carrying space except for the hatches. These, however, are insulated,
really being wooden boxes about 10 inches deep, cork filled. They are
neat fitting when shipped, the upper ones usually being caulked with
oakum to reduce air leakage. Sometimes further precaution is taken
by spreading a 3-meh layer of sawdust over them, “blind” hatches
being shipped overall in the usual manner. All ventilators are fitted
with wooden insulated plugs which are clamped in position from inside
the hold.
The illustration shows the method of insulating a refrigerating
chamber showing some of the sections lifted and the brine pipes on the
bulkheads.
Fig. 5.
The Cooling is obtained by means of pipes of about 1| inches diameter
through which is circulated brine of a density of about 1047 ounces at a
delivered temperature of about 10° F. These pipes are secured to the
wooden sides, bulkheads, and deckheads of the holds, more piping
being fitted in the upper than in the lower portion of the spaces {hold or
deck). 3-inch square battens are nailed athwartships on the floors,
being spaced about 14 inches, and 2-inch square battens are nailed
vertically to the sides and bulkheads. These battens prevent the meat
from being stowed closely against the boarding and consequently
losing the air circulation. All pillars, ladders, etc., are lagged with
rope. When the hold is loaded, the temperature is ascertained by
means of thermometers which are lowered through pipes from the
weather deck.
The Preparation of the Hold for meat is important. The pipes and
sides of the ship, which are varnished, are washed down with a disin-
412 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
fecting fluid (carbolecene is frequently used). The floors are washed
clean, scrubbed if necessary and then whitewashed When this is
dry the ventilator plugs and hatches are shipped and “cooling down”
commences. If time permits, coohng down is commenced at least
48 hours before loading, so as to thoroughly bring down the temperature
of all metal work Trouble is frequently experienced from sweating,
and burlap is usually employed to keep the meat off the hatch coamings,
etc.
The holds are generally brought down to about 10° F. when “cooling
down” so as to keep a good hold on the job whilst actually loading.
Frequently while loading m hot weather the temperature rises to 25° F.,
and occasionally so high that work has to be suspended and the holds
closed until a lower temperature is regained.
Sometimes in warm damp weather the pipes become heavily coated
with snow; when this occurs it has to be swept off, as snow partially
insulates the pipes and reduces their efficiency. When this procedure
is resorted to, care must be taken to prevent the*snow from dropping in
large quantities on the meat as it is liable to knit the carcases together
so securely that considerable force—even wire runners—has to be
employed to break them out.
At all times great care must be observed regarding cleanliness.
Uncovered boots must not be permitted in the holds, and canvas
“savealls” must be placed over the meat used for a landing in the square
of the hatch. The loading being finished, additional pipes called
“grids” are fitted in the hatchways and coupled up to the brine circula¬
tion system. This done, the insulated hatches are shipped and ca ulked.
For frozen produce such as mutton, lamb, beef, pork, butte r *r, etc.,
a temperature of about 15° F. is maintained throughout the pass‘ a age.
When Receiving Cargo, “soft” meat should not be accepte* d as a
few soft carcases may easily rot and contaminate hundreds of Mothers.
If carcases come m soft they may sometimes be traced to tht?| tops
of railway trucks which h?~e been delayed in transit betwee^ the
freezing works and the ship Bulkheads separating insulated Molds
from those which are not insulated generally sweat considerably on fthe
non-insulated side, and the ca:jo should be kept well clear of them,
Chilled Meat is carried in ships which have their holds insulated in a
manner similar to those employed in carrying frozen meat. It is hung
from the deckheads and carried at a temperature of about 29° F.
Chilled meat is being successfully carried in large quantities from the
REFRIGERATOR CARGOES
413
River Plate, but on tie longer voyage from the Colonies the trade is
yet an experimental one.
The cross section through a ship shows the arrangement of refriger-
ating plant on the CO„ system adapted for carrying“mixed cargo, such
as frozen or chilled meat m the holds and fruit or dairy produce m the
tween decks. The holds are cooled by brine pipes and the ’tween
decks by air circulation, the air being cooled through being circulated
by a fan over a nest of brine pipes. Arrangements are usually made in
the air trunks for replacing the air in these chambers by fresh air when
required. See also pages 607-609.
Fig. 6.
Carriage of Fruit,—The insulation for fruit carrying is similar to that
for the carnage of frozen meat, in fact fruit is often canned in << mest”
ships. It is important that a good air circulation should be maintained
throughout the hold and that the fruit is carried at the proper
temperature.
The different kinds of fruit are carried in cases or boxes (skeleton or
otherwise) of a size and design best suited to keep it in good condition.
Colonial apples are generally packed in skeleton cases, choice fruits
from South Africa and Australasia being shipped in small boxes. Laths
or 1-inch square battens are used to separate the packages and allow
the air to circulate between them. Some Colonial apple cases are
designed to allow air circulation without the use of loose battens to
separate them.
414
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Apples are generally carried at a temperature of 40° F to 43° F.,
other fruits at different temperatures according to shipper’s instructions
Large quantities of apples shipped from Canada and United States
are packed in barrels.
The methods adopted for the carnage of bananas are quite different
from those employed for the carrying of other fruit. Bananas are a
cargo which present considerable difficulties during their carriage by
sea as they easily either chill or ripen, and as they are shipped green
and must be delivered in a particular state of advancement their
transport calls for great care and constant and skilful attention.
They are carried in specially constructed steamers which are only
employed in that trade. The holds are insulated similarly to those
of meat carrying steamers, but trunkways, just broad enough to permit
the people in charge to walk through, separate the fruit from the in¬
sulation. Thermometers are fitted in these trunkways, their readings
bemg taken and recorded at regular intervals. The holds and “decks”
are subdivided into numerous compartments called “bins,” each being
about 20 feet square. The bananas are stowed in these bins.
To regulate the temperature in the holds, the outside air is cooled
by passing it over brine pipes which are situated in special houses on the
upper deck It is then forced through the trunkways by large fans
also situated in the special houses, which are termed “coolers.”
In these ships the hold temperatures are reduced to about 37°
F. when “cooling down,” but this rises to about 70° F. during loading
operations.
The loading being finished and hatches secured, the hold tempera¬
tures are gradually brought down again to about 53° F., which
temperature is maintained throughout the voyage.
About 300 stems are placed in a bin stowed yeftical and sometimes
overstowed with one row of stems on their sides. The upper part of Fig. 8
REFRIGERATOR CARGOES
415
shows a side elevation, the small squares being peep holes, fitted with
sliding shutters, for inspection of the fruit One ripe banana generates
heat which sets up a “nest” or centre of ripening fruit which will quickly
spread throughout the whole bin unless it is removed. The lower
part of the figure shows in plan the breadth of a ship with insulated
hold and bins side by side.
Arrangement
Fig 8.—Side View and Plan of Bins and Ventilating System.
The refrigerating plant circulates cooled brine through nests of
pipes which reduce the temperature of the air in contact with them.
The cooled air is circulated through the fruit chambers by powerful
fans driven by electric motors. The air is driven into the air trunk
which forms a passage-way between the ship’s side and the bins,
afterwards passing through the fruit chamber and returning to the
circulating machine.
416 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
The conveyance of food is a specialised trade and detailed instructions
-are issued to their officers by the firms engaged in it regarding such
cargoes, as apples, oranges, bananas, cheese, eggs, butter, beef and other
commodities which are “chilled” as distinguished from meat which is
kept frozen. The stowage of the goods, their supervision during
transit and their handling when being loaded and discharged, are
described in the private book of instructions issued by the company,
and particular reference is made to the pre-cooling temperatures of
the chambers at shipment, the maintenance temperatures during the
passage and the temperatures desirable on opening up the chambers
prior to discharging. For example, the temperature during the voyage
for frozen meat is 15°; for chilled meat about 29°; for apples and butter
about 33°; oranges and cheese about 40°; bananas about 53°.
A Tanker is a ship specially designed to carry liquid cargoes such as
oils, molasses, and creosote in bulk, about 7,000,OCX) tons of various
oils being imported annually into the United Kingdom. Such vessels
are divided into separate oil-tight compartments by means of transverse
and longitudinal bulkheads.'
The compartments of an oil-carrying ship are indicated m the
illustration (see p. 417) and, beginning at the bow, we note—
1. The forepeak tank forward of the collision bulkhead.
2. A hold for dry cargo with two deep water ballast tanks for
trimming the ship.
3. A cofferdam extending the whole breadth of the ship and the
depth of the tank. Cofferdams must be fitted at each end
of the oil tanks to protect the other parts of the ship from
gas. The space between the bulkheads of the cofferdam
must be at least 3 feet.
jti series of tanks numbered 1 to 11. The diagonal lines across
each compartment denote that a longitudinal bulkhead is
fitted. The side summer tanks are shown both in the profile
and in the plan.
5. This ship has two oil pump rooms, one midway along and the
other at the after end of the tanks. The pump room in the
forward cargo hold is for the water ballast tanks.
6. Abaft the after pump room is the cofferdam separating the
oil tanks from the engine and boiler spaces. Note the
balanced rudder and the cruiser stem of this ship.
7. The plan shows the position of the hatches giving access to the
expansion trunks and to. the summer tanks.
418
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Tanks cannot be completely filled with oil as allowance has to
be made for expansion due to increase of temperature. The main
tanks are kept quite full by keeping a reserve of oil in the trunk. The
space above the surface of the oil in the trunk is called the “ullage,”
and, obviously, any change in the ullage scale indicates the change in
the volume of the oil due to change of temperature. See Fig. 6, page
365. Heavy oils when heated expand about 1 per cent for every 25°
of temperature.
An increase of 10 degrees m the temperature of 5000 tons of oil
would increase its volume to the capacity equivalent to 20 tons weight
which means that, approximately, 6400 more gallons would be pumped
out at the higher temperature than was taken in at the lower
temperature.
Fig. 10—Stop Valves.
When heavy oil is too viscous, that is very thick or congealed, it
cannot be pumped out, so heating pipes are either laid along the bottom
of the tank or arranged in coils to raise the temperature of the cargo and
reduce its viscosity. Some liquid cargoes have to be kept above a
given temperature, but generally the heating up of oil is only necessary
for a few days before arrival in port.
Figure 10 illustrates stop valves to admit steam to the coils
in the port or starboard tanks separately or simultaneously, and the
TANKER CARGO
419
attings at the exhaust end of the coils as installed by Messrs. T. B.
Bdton & Sons, North Shields.
The trunkway increases the stability of the vessel by reducing the
surface area of the oil All liquid cargoes are unstable if the tanks are
not completely filled and this cannot be done in tankers, so when the
ship rolls at sea the free liquid shifts from side to side and if the quantity
were excessive the ship would be liable to capsize. The middle line
bulkhead being carried to the top of the trunk divides it so that the
volume of free oil is comparatively small and ineffective.
The side tanks may be used for oil, dry cargo or bunkers, if required
to put the ship down to her load line. When loading light spint in the
summer season the main tanks are not in themselves usually of sufficient
capacity to put the ship down to her summer mark and the summer
tanks are then utilised. The specific gravity of oil vanes with its
temperature from about *98 m the case of heavy oils to about *85 for
petroleum.
Tube ventilators capable of being opened and closed are fitted to the
tanks to admit air, or to allow the gas to escape, and they may be
legulated to prevent undue evaporation from spirit cargoes, otherwise
there would be considerable loss in quantity. The air pipes may be
led from the tanks to a considerable height, sometimes up the masts,
to carry vapour well clear of the ship when loading or discharging
highly inflammable spirit, the tanks being, of course, kept closed during
the operation.
When the cargo is pumped out every precaution must be taken to
ensure that the empty tanks are gas free, the ship being provided
with suction fans to draw off heavy gases up through piping, or with
steam injectors which create a vertical current and serve the same
purpose.
Oil cargoes are pumped in and out through flexible metallic hose
either by pumps on board or on shore. The pumping and piping
system forms a most important part of a tanker’s outfit, the plant
installed in modem ships being capable of pumping up to 500 tons of
oil per hour.
Two main pipe lines are usually led from the several pump rooms
with branch lines connecting up to each tank and fitted with control
valves, so that the tanks may be worked hujependently or in groups,
or oil may be passed from one tank to another by simply manipulating
the proper valves. Needless to say, one of the first duties on joining
a tanker is to study closely her pumping plan, and to understand and be
420
NICH (ALLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
thoroughly familiar with the system, the position and operation of all
valves and cocks, the connections which they make and the various
combinations of tank control that are possible. Valves which control
pipes in direct communication with tanks are operated by rods from deck.
Special Precautions must be taken to prevent outbreak of fire, and
oil-carrying ships are well provided with fire-extmguishmg apparatus,
nevertheless it is the duty of responsible officers to be continually on
guard and to frequently warn inexperienced and careless persons
against the danger which may arise from smoking, accumulation of
gas in closed spaces and tank bottoms, the creation of sparks when
working with metal tools, or any frictional contact that may generate
sufficient heat to ignite inflammable gas.
It is well to distinguish between the Flash point and the Ignition
point of oil. The flash point is that temperature to which oil must
be heated to give off vapour in sufficient quantity when mixed with
air to be ignited by a flame. The ignition point is the temperature to
which the oil must be raised before its surface layers will go on fire.
The flash point is an explosive temperature which is lower than the
ignition temperature, the difference varying from 35° to 60° Fahrenheit
in the case of fuel oils. Explosion, therefore, precedes fire. Guard
against explosion. The flash point of spirit is below 75° Fahr.
CARGO PLANS.
J** POUT
Z~°po rt
Fig. 11.
■w
3*6 POUT
When a mixed cargo is to be loaded for several ports it is desirable
to draw up in advance a rough plan of where the cargo is to be stowed,
so that goods for successive ports may be readily got at in their order
of discharge. An equality of distribution of the goods must also be
considered so that several hatches may be worked in each port and the
discharge at all hatches completed at the same time if possible. The
plan in Figure 11 shows a system of identification marking for a cargo
CARGO PLANS
421
as loaded so that the owners, stevedores and consignees may see at a
glance where the cargo is stowed. Horizontal lines indicate cargo
for a first port of call, diagonal lines for a second port and vertical
lines for a third port. A distinctive colouring of the cargo for each
port might have been used, which would probably have been more
attractive but not so easily reproduced m a book.
Consideration has also to be given to the question of the ship’s
stability when distributing the weight of cargo in the ship, but this
subject is dealt with in Chapter XVIII.
The measurement cargo capacity of a ship is known and is given
in her capacity plans, and the deadweight tons to put her down to the
load line marks is definitely fixed by statute. These two tonnage
values, measurement and weight, automatically adjust themselves
when a homogeneous cargo is loaded, for, obviously, if the ship is full
no more goods can be stowed on board even if she is not down to her
statutory load marks, and, conversely, if she is down to her load line
marks, even if her holds are not full, no more weight can be put on board
under pain of severe penalty for overloading
But when a cargo consisting of goods of different densities is to be
carried it may be desired to have the holds quite full and at the same
time have the ship down to her statutory load line. The determination
of the proportion of quantities calls for the solution of a simultaneous
equation which may be best illustrated by a worked example.
Example —A vessel of 9300 tons deadweight, loading in Calcutta,
has on board 1200 tons of coal, stores and water. Her hold capacities
in cubic feet are No. 1, 90270; No. 2, 108860; No. 3, 20750; No. 4,
102620; No. 5, 89370. Her cargo is to be 500 tons tea stowing at 110
cubic feet per ton, the remainder to be manganese ore in bulk at 18
cubic feet and gunny bales at 60 cubic feet per ton. Required the
quantities of each to fill the ship when floating at her load line draught.
Draw up a cargo plan for your calculated quantities.
Let #=quantity of ore, and y=bales
Total deadweight 9300 tons
less coal 1200 tons
„ tea 500 „ * 1700 tons
I. Weight of ore and bales z+y = 7600 tons
Total hold capacity 411,870 cub. ft.
less 500 tons tea at 110 cub. ft. 55,000 „
Space for ore and bales = 356,870 „
422
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
ll * 18®+60y=356,870
Multiply Eq. I. by 18 18z+18y=136,800
Subtract
42y=220,070
y= 5240 tons
® + y= 7600 „
jr_= 2360
Ore =s=2360 tons X 18 cub. ft. = 42,480 cub. ft.
Bales =y ==5240 „ X 60 „ =314,400
7600 tons
=356,880 cub. ft.
EXERCISES
1. A deep tank 42,280 cubic feet is filled with oil at 37-6 cubic feet
per ton instead of sea water, required the difference of weight in tons.
Answer .—83*5 tons.
2. A hold of capacity 55,000 cubic feet has 100 standards of timber
at 270 cubic feet per standard stowed in it. How many bales of flax
could be stowed in the remaining space at 115 cubic feet per ton and 5
bales to the ton.
Answer .—243 tons, 1217 bales.
3. Convert the following cargo items into tons weight, give the
total cubic capacity and total weight, (i) 300 rolls of paper, length
42 inches, diameter 36 inches, stowage factor 95 cubic feet per ton;
(ii) 100 cases of pianos 6 ft. X 5 ft. x2 ft. 6 ins., stowage factor 160 cubic
feet per ton; (iii) 400 tons cased goods at 40 cubic feet per ton.
Show by a cargo plan how you would stow the goods in a
single hold ship with engines aft and two hatchways, ship full.
Answers— Paper 7425 cub. ft= 78,-2 tons
Pianos 7500 „ 46-9 „
Cases 16,000 „ 4000 „
30,925 525*1
CARGO PLANS
423
4. A ship’s No 4 hoid measures 70 ft. X53 ft. X28 ft., the tunnel
extends throughout its length and is 7 ft. high and 5 ft. wide.
Bales of high density cotton at 50 cubic feet to the ton are stowed
level with the tunnel top. How many standard bales of cotton measur¬
ing 5 ft. x2 ft. 6 ins. X2 ft 6 ins. can now be stowed m the hold, and if
the standard bales weigh 450 lbs., what? will be the total weight of
cargo in the hold?
Answer — H D. bales 470*4 tons
Standard bales 2493 or 500 3 tons
Total weight 971 *2 tons
5. A hold measures 32 ft. X26 ft Xl4 ft. 6 ins Dunnage is laid to
an uniform depth of 6 inches.
10,000 boxes of tinfoil 14 ins. X6ins. X3 ms , and 4000 drums of
paint 21 ms. high and 12 ins diameter are stowed in the hold, 5 percent,
bemg allowed for broken stowage for the paint. [Required the cubic
capacity remaining in the hold, and also how many cases of goods at
25 cubic feet to the ton can now be stowed in the hold allowing 4 cases
to the ton.
Answer. —4415 cubic feet, 176*6 tons, cases 706.
6. A ship’s double bottom tank holds when full 335 tons sea water.
Calculate how many tons of oil fuel it will contain when 95 per cent,
full and specific gravity of oil 0*96. Sea water 35 cubic feet per ton,
fresh water 36 cubic feet per ton.
Answer. —297 tons oil.
7. A consignment of tubes is stored on the quay in triangular
heaps 3 ft. high and 4 ft. base, the tubes being 8 ft. long. If 24 of
these heaps are transferred to the hold and stowed on a deck space of
40 ft. X 16 ft. to what depth will they lie?
Anstoer .—1 ft. ins.
8. If 5000 cases, 2 ft. X2 ft. Xl ft., are discharged at an intermediate
port, 5 per cent, of their volume having been allowed for broken stowage,
find how many tons of bagged sugar, stowage factor 50 cubic feet,
will fill the space.
Answer .—420 tons sugar.
9. A single deck ship of 3500 tons deadweight has fuel and stores
on board amounting to 420 tons, and also 60 tons fresh water- She baa
424 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
to load esparto grass stowing at 110 cubic feet per ton and ore at 15
cubic feet per ton. How much of each can she take to fullest capacity
of space and tons weight?
Hold capacities in cubic feet are—
No. 1.. 51420 No. 2. 55350
No. 3. 43210 No. 4. 38883
Draw up a plan of loading and stowage of the cargo.
Answer .—1511 tons grass, 1509 tons ore
10. An oil tanker has 2 tanks each 30 ft. long, 26 ft. broad, 33 ft.
deep, divided by a midship bulkhead. Crude oil stowing at 41*34
cubic feet to the ton is loaded to an ullage of 2 ft. 4 ins. in both tanks.
What is the weight of the oil in both tanks?
If on heating before discharging the cargo expands 2 per cent.,
what will then be the ullage?
Answer .—1157 tons, 1 ft. 8J ins. ullage
QUESTIONS
1. When does the ship’s responsibility for the good condition of
cargo begin and end?
2. Describe types of slings and gear used for slinging different kinds
of cargo.
3 What is a “bull” rope?
4. Describe the usual arrangement of derricks and winches in an
ordinary cargo ship.
5. The ship has just completed loading; state what should now be
done with regard to hatches and cargo gear preparatory to going to sea?
6. Describe the preparatory work of getting cargo gear rigged for
discharging cargo. What is usually done before the hatches are taken
off?
7. Describe the starting and stopping of a steam winch and the
precautions necessary on occasions.
8. Distinguish between permanent, portable and temporary dunnage.
9. What is a “homogeneous” cargo?
10. What precautions are taken with regard to the loading and
ventilating of coal? How can one tell if the cargo is overheating?
11. What has to be kept in view when loading heavy cargoes such
as ores, and how are such cargoes stowed?
12. Why are special precautions taken with grain cargoes?
QUESTIONS
425
13. Describe the preparation of a hold for grain in bulk.
14 Describe the system of ventilating a cargo of rice.
15 You are responsible for receiving cargo, what precautions
should be taken to safeguard the ship's interests?
16. Where should the following goods be stowed, and why:—Acids,
explosives, dynamite, oil m barrels, matches, tallow?
17 When is a vessel said to be “gram” laden?
18. How is a separation made between bag and bulk grain m the
same hold?
19. Describe how temporary grain feeders are constructed, why
they are necessary, and what capacity they should be.
20. Why are oil cargoes in drums or barrels particularly dangerous
and what safeguards are taken with them?
21 When loading a deck cargo of timber what precautions must be
taken with regard to deck openings, protection of crew, steering gear,
cargo lashings?
22. State what you know about the insulation of ships’ holds and
the carriage of frozen meat.
23 How are the foliowing foods stowed:— Frozen mutton, chilled
beef, bananas?
24. Give the temperatures at which some perishable cargoes are
carried in refrigerator ships during transit.
25. What is meant by “ullage” in a tanker?
26. Wlty are trunks and summer tanks fitted in tankers?
27. What extraordinary precautions are exercised when carrying
petroleum spirit in bulk?
28. Describe the pipe line arrangement of a tanker. Who controls
the cargo valves?
29. Explain what is meant by the “flash” point and the “ignition”
point of oil. -i
30. What parts of the hold are specially dunnaged?
31. How is a hold made grain-tight?
32. Who is made responsible for the ship complying with the Grain
Laws and what penalties may be imposed, and on whom?
33. You are loading the following cargo, what form of slinging
would you adopt and what quantity per sling (i) iron tubes; (ii) bales;
(iii) bags of salt; (iv) cement in casks; (v) oilman’s small stores; (vi)
reels of paper?
CHAPTER XVII.
SHIP CONSTRUCTION.
A Ship is a Girder—A ship considered as a structural unit is a
girder, a box or beam girder, composed of many small girders braced,
supported and tied together so that the strength of the ship as a whole
is dependent upon the effectiveness of all her members, and she is no
stronger than her weakest component although some parts are more
vital to the floating structure than others. The science of shipbuilding
is directed to the designing and assembling of the several parts of the
vessel in a practical and economical manner so that the ship may
conform to the regulations laid down by the registration societies and
yet be as light in weight as possible consistent with strength, rigidity
and seaworthiness
a- a
Fig. 1.—A Girder.
Longitudinal Stresses—Figure 1 represents a narrow steel plate
standing on its edge, the ends resting on supports A and B. It is a
simple girder. If a heavy load C be suspended from its middle point,
Fig. 1
(Figure 2), the edges of the plate will be subjected to stresses, compression
on its upper edge and tension on its lower edge, with a line of unchanged
strength or neutral axis, DE, between. Should the load be excessive hue
426
STRESSES ON A SHIP
427
upper edge would crumple up and the lower edge break asunder,
girder would be fractured and shotf signs of strain.
The
Fig 3 —Girder Strengthened with Flanges.
By stiffening the edges of the plate with angles as m Figure 3, the
girder will now be able to resist distortion due to the weight C. The
vertical plate is called the web of the girder and the edge angles its
flanges. The web could now be made thinner and the arrangement
gives a more efficient girder than the simple plate
A converse condition would arise when the girder, supported at its
middle point A , is called upon to support loads B and G at each end
as in Figure 4. The upper edge will now be under tension and the lowei
edge under compression, with the neutral axis DE between.
A ship when afloat is subjected to similar stresses, not merely by the
loads placed on board but more seriously when working in a seaway.
Figure 5 represents a ship supported at each end on the crests of two
waves, the weight of the hull and its contents being represented by a
Fig. 5.—Sagging.
load at C. The load is, of course, not concentrated but is distributed
over the length in various degrees of concentration. The upper edge
of the ship is under compression, and the lower edge under tension
428
NICHOLAS ttJ£AMANSHIP AND NAUTICAL KNOWLEDGE
with a neutral area D E between; and if the hull of the ship were not
made strong enough to resist these stresses she would bend downwards
at the middle of her length This is called “sagging.”
When the ship is supported amidships on the crest of a single wave
as at A (Figure 6), with the ends B and C unsupported, the stresses are
changed to tension on the upper edge and compression on the lower
edge with a neutral area D E between, and if the hull were not made
strong enough to resist these stresses she would bend upwards and sufEer
excessive stresses at the middle of her length. This is called “hogging ”
These longitudinal stresses occur alternately when a ship is among
waves and the ship girder has to be specially strengthened and stiffened
along the length of her strength deck by means of “sheer” strake,
“stringers,” etc., and along the lower edge by means of centre keel, side
“keelsons” and “longitudinals” in order to make the hull strong
enough to withstand all normal hogging and sagging stresses.
Fig. 6.-—Hogging.
Transverse Stresses.—The ship is also subjected to transverse racking
stresses when rolling in a seaway, the tendency of which is to cause
distortion at the corners of the box-shaped girder. A simple transverse
section consists of a “frame,” or rib, extending the whole girth of the
ship, the top ends being held firmly in position by means of a transverse
beam. The beam is connected to the frame by means of a bracket called
a beam “knee,” which is made triangular in shape and of sufficient
depth and breadth to get a good rivet connection to the beam and
to the frame.
The strain of racking is likely to be more evident at the top comers
than at the bottom part of a transverse section as the upper works are
relatively weaker owing to deck* openings and other sources of weakness
in the higher parts of the struqture, whereas the “floor” and “bilge”
brackets make the bottom part of the section more solid and rigid.
Figure 7 shows excessive distortion. The dotted lines represent
the original shape of the vessel. The frames, pillars and bottom
STRESSES ON A SHIP
429
longitudinals have evidently been thrown out of line due to severe racking
strains, and fractures would be looked for at all the top and bottom
corner connections.
Collapsing Stresses.—The water presses inwards on every submerged
part of the ship m a direction perpendicular to the skin surface with a
force which increases at a uniform rate of 64 lbs. per square foot for
every foot depth of water. The function of the skeleton framework
of the ship is to keep the shell plating to its designed shape. The
plating is comparatively thin and flexible and it might readily yield
inwards to the pressure of the water were it not for the frames and
other stifleners. When the ship is under way the plating has to push the
Fig 8.—Collapsing Forces.
water away at the bows, and in doing so has a tendency to vibrate, or to
move out and in, these pulsations being called “panting.” When the ship
is pitching' into a head sea excessive pounding is set up forward and aft
when she rises and falls, the local stresses at the stem being aggravated
by the racing of the propeller. Evidence of this is made obvious on
occasions by strained plating and slack rivets. The ship girder is,
therefore, specially strengthened at the ends by means of “panting”
beams, thickened plating, “breasthooks,” “crutches,” closer spacing of
430 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
frames, stringers, deeper floors, etc., to enable the shell plating to resist
its tendency to flexibility when sub]ected to panting stresses
The concentration of heavy weight along the middle line of the
hold introduces a collapsing stress which tends to draw the two sides
of the ship together. This fact was made noticeable when sailing ships
loaded heavy cargoes such as nitrate in Chile, copper ore in Australia,
etc. The lower layers of such cargoes were usually stowed out to the
bilges and gradually narrowed in towards the middle line, leavmg a
space between the cargo and the ship’s sides as in Figure 9. The
ngging invariably slackened when the vessel was loaded and had to be
tightened up by taking a turn or two of the box screws of each shroud
and backstay. The fact was usually noted in the chief officer’s log
book as a reminder that the rigging had to be slackened back again
before the cargo was discharged, thus allowing the hull freedom to
resume its original shape.
The opposite effect is created .when a ship is in dry dock. The
weight of the hull on the keel blocks pushes the bottom of the vessel
STRESSES ON A SHIP
431
upwards which tends to bulge the sides outwards, hence the necessity
for shoring the bilges and sides to assist the hull to keep its shape.
Local Stresses.—Stresses are also set up when weights are unequally
distributed m the ship as in Fig. 12, which is intended to represent a
vessel divided into watertight compartments some of which are empty
and others laden with cargo. Unequal vertical stresses are thus created,
a downward pressure in the laden compartments and an upward pressure
in the empty ones, as, of course, the ship floats at a draught which
corresponds to the mean weight of the hull and its contents. Suppose it
were possible to disconnect the several compartments and that each
one had sufficient buoyancy within itself to float upnght, then the
loaded compartments A , G and E would come to rest at a deeper
draught than the mean draught, and the lighter compartments B
and D would float at a draught lighter than the mean. 4
Fig. 12.—Vertical Stresses,
Localised stresses are also set up in the way of deck machinery
such as windlass, cargo winches, derricks, steering gear, etc., and the
structure in their vicinity is stiffened by thickening the plating, putting
in additional or stronger beams, and arranging the material so that the
local stress may be distributed to adjacent parts and not centralised
too much at one place.
This very general and brief reference to the stresses thrown upon the
ship’s hull when considered as a compound girder may direct the mind
of the student to the fact that the longitudinal and transverse frame¬
work of the ship is designed to enable the shell plating to keep its form
and to resist any distortion and strain which might produce a leaking
hull. The structure must, therefore, be made rigid enough longitudin-
432
NICHOLLS S SEAMANSHIP AND NAUTICAL KNOWLEDGE
ally and transversely to withstand all the normal stresses to be expected
when the ship is labouring at sea with her cargo intelligently distributed
and securely stowed.
The longitudinal framing consists principally of keel, stem and
stem posts, keelsons, bottom longitudinals, margin plates, stringers.
The transverse framing consists of floors, frames and sometimes reversed
frames, tank side brackets, beams, beam knees and pillars. The shell,
inner bottom and deck plating also add considerably to the strength of the
ship and form the most important part of the structure, not merely
because they are vital to her flotation but because the plating is the
heaviest iten^ of all the components.
We shall now discuss these several members of the ship.
A TRANSVERSE SECTION.
Figure 13 shows a few frame sections at the midship part of a sailing
ship, or of any vessel fitted with open floors. It has been drawn to
give us an opportunity of introducing to ourselves the names of the
several components of the structure and their particular functions.
First, note the “bar” keel secured to the hull by means of the “garboard”
strakes; these are the two strakes next to, and on each side of, the keel.
The garboard strakes are “flanged” or bent down to fit against the keel
to which they are riveted, and they provide the only connection between
the keel and the hull.
The Frames extend from the upper deck to the keel and, in earlier
types "skips, a “reversed” frame was riveted to the frame so that the
twcfangle bars when riveted back to back formed a very rigid rib.
The reversed frame in our figure is separated from the frame angle at
the turn of the bilge at the floor head, and is carried along the top edge
* of the “floor” to which it is riveted, whilst the frame bar is riveted to
its lower edge thus stiffening very effectively both edges of the floor
plate.
The “Floors” are the vertical plates extending from bilge to bilge
between the inner and outer bottoms. Sailing ships had no inner
bottom plating riveted to the top of the floors, just planks laid fore and
aft, some of them portable so that the spaces between the floors, named
the “limbers,” could be cleaned and dried up. a very important operation
prior to loading cargo.
Beams.—The top ends of the port and starboard frames are tied
together by means of a beam, the beam being efficiently connected to
434
NICHOLAS SEAMANSHIP AND NAUTICAL KNOWLEDGE
The Midship Pillars in the figure are riveted to the beam above and
to the beam below, the bottom ends of the hold pillars being riveted
to the top of the “centre keelson.” The pillars are not merely supports
to prop up the beam above but act as ties to bind together the upper
and lower beams
The Transverse Sections, shaped to the form of the ship and consisting
of frames and reversed frames, floor, pillar, beam and beam knees are all
practically the same and spaced from 21 to 36 inches apart according
to the dimensions of the ship. The frame spacing is reduced at the
ends of the ship to strengthen the hull against the effect of panting
and pounding when m a seaway, as the frames being much straighter at
the how and stem are less able to resist inward pressure. Refer to the
plan of Caledonian Monarch and note that the 28-inch normal spacing
of frames is reduced gradually to 24 inches from frames No. 14 aft
and from frame No. 168 forward.
The Longitudinal Framing keeps the transverse sections in their
correct relative positions. Note the “centre keelson,” composed
of a vertical plate with two angle bars on its lower edge and two on its
upper ^dge. A flat plate, called a “rider” plate, is riveted to the hori¬
zontal flanges of the top angles, the whole combination forming a very
strong centre girder or backbone for the ship. The angles on the lower
edge of the centre plate axe riveted to each reversed frame and to a short
‘Tug” piece on the top edge 6f the floor, all as further illustrated in
Figure 14.
The Centre Keelson .—A is the vertical plate standing on the floors.
B x and B 2 the stiffening angles on its upper and lower edges respectively.
C the rider plate riveted to the horizontal flanges of angles B v D, a
foundation plate laid along the top of the floors and riveted to the
reversed frames G s to the lug piece E and to the horizontal flange of
angle B 2 . F is the floor plate.
KEELS AND KEELSONS
435
A Side Keelson is shown in Figure 13 consisting of two bulb angles
riveted back to back with a plate fitted between them The inter¬
costal plate is not shown on the drawing of the side keelson but it is
similar to that on the bilge keelson The horizontal flanges of the
two angle bars are riveted to each reversed frame and to a short lug
piece.
A Bilge Keelson is also shown m the drawing. It is built up of a
series of vertical plates, one into each space, the ends of each plate
fitting tightly against the floors. The lower edge of this intercostal
plate is riveted to the shell plating by means of a short mtercostal
angle. The word “intercostal” is derived from infer meaning between
and costa a rib. The top edge of the intercostal extends a little above
the floors and is stiffened by two angles riveted back to back, the
horizontal flanges of the angles being riveted to each # hversed frame
and to a short lug piece as indicated in the drawing
e
Bilge Keels are frequently fitted on the outside of the bilge
strakes for about half the vessel’s length amidships to act as anti-
rollmg chocks They consist usually of a rolled bulb section the
edge of which fits between the vertical flanges of two continuous fore
and aft angles. Sometimes one angle only is used; in any case the
section is riveted to the angle and the horizontal flange of the angle
is riveted to the bilge strake. Bilge keels also add longitudinal
strength to the vessel.
Fig. 15.—A Bar Keel.
Detail of a Bar Keek— A, the bar keel, secured to the frame C by
the garboard strakes B, a further riveted connection being got by
heel piece G. F is the floor, D the reversed frame and E a lug piece.
In Figure 16 (i) the nvefes G and G pass through the garboard
strakes B and bar keel A } and (ii) represents a side bar keel, the rivets
bolding five thicknesses together.
436
NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
A
(/) (!•)
Bar Keel. Fig. 16. Side Bar Keel.
Figure IT (i) and (n) siiow how a centre line keelson is attached
to its neighbouring members. The centre through plate A is stiffened
on its upper edge by the two continuous angles B , the horizontal flanges
of which provide a rivet connection to the reversed frames and the lug
pieces marked d . The lower edge of the keelson plate is connected to
the keel plate by means of the two angles k , and to the floors by means
of short vertical angles marked a. In Figure 17 (ii) a foundation plate
D is shown, and the angles at k are continuous, the frames being cut
to admit of this, but in Figure 17 (i) the frames are continuous and pass
through notches cut in the lower edge of the keelson plate, the angles k,
in this case, being fitted in short lengths between the floors.
Stringers.—Above the turn of the bilge there is a “stringer,” similar
in construction to a keelson. These longitudinals are named stringers
when they are attached to the frames, and keelsons when attached
to the floors. They have similar functions, both contribute longi¬
tudinal strength, and help to stiffen the shell plating by keeping the
frames and floors in their correct relative positions so that they all
act together.
The hold stringer in Figure 13 is formed by a narrow plate which is
notched round each frame, the outer edge of the plate touching the shell
plating to which it is riveted by means of short chock angles fitted
intercostally between the frames. The inner edge of the stringer plate
is stiffened with a continuous angle on its under side, the vertical
STRINGERS
437
flange of the angle providing the means of getting a rivet connection
between the stringer plate and each reversed frame.
A Stringer Plate is fitted to the lower deck (Fig. 13), its chief purpose
being to further strengthen the connection between the beams and the
frames and to keep the beams square to the shell. Incidentally the
stringer plate forms a narrow side platform, to walk upon as a deck has
not been laid on the lower deck beams.
This, briefly, is a very general description of the framework in the
type of ship illustrated. The skeleton having been built up we can
easily imagine the skin or shell plating being put on, the sunk strakes
first and then the raised strakes. It will be observed that the “sheer”
strake, which is the strake at the upper or strength deck of this ship,
extends a little above the level of the beams. This is done in order
to get a watertight connection between the deck plating and the sheer
strake and to offer a landing for the bulwark plate. A continuous
stnnger angle is riveted to the sheer strake and to the stringer plate;
the stringer plate is the strake of deck plating next to the ship’s side
and it is invariably thicker than the other deck plates.
When a wood deck is laid as shown in Figure 18, a “gutter” angle is
riveted to the deck plating to form a strong boundary for the planking,
and also to make a gutter, into which water drains from the deck
before it runs out through the scupper holes.
The strakes of shell plating are not all of the same thickness, the
sheer strake is the thickest, the bulwarkstrake the thinnest, and, curiously
enough, the thickest and thinnest are riveted together in our sailing *
438 NICROLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
vessel. The gar board strakes are next in thickness to the sheer strake,
the thickness of the others being varied slightly. The extreme thickness
of the various strakes is maintained for half the midship length of the
ship and thinned off towards the ends. In shipyard practice the
strakes of plating are lettered A, B, G, etc., from the keel upwards and
the plates in each strake are numbered from aft forward; thus
shell plate 0 12 is the third strake up from the keel and the twelfth
plate from the stem.
McIntyre Tank.—Figure 19 represents the formation of a “Mc¬
Intyre” tank. It is really a superstructure placed on top of a ship’s
ordinary floors when water ballast is earned for only a portion of the
length of the ship. The McIntyre system was the forerunner of the
cellular double bottom method of providing water ballast space.
A is a centre plate keelson with a* indicating the stiffening and
connecting double angles at its upper and lower edges, and the
lug piece to get'an extra rivet connection to the floor.
B is an intercostal centre plate fitted between the floors. It is
connected/ to the floor plate by means of a short vertical angle b , and
its lower edge is riveted to the “flat” plate keel by means of the short
fore-and-aft intercostal angle & 2 .
C, C 3 C and 0 are longitudinal plates standing vertically on top of
the floors and connected to the reversed frame by the continuous
fore-and-aft angles c z> % and lug piece c 4 . The top edge of the plate
is stiffened with a continuous angle bar to which the tank top plating
E is riveted. F indicates the floor plate.
Watertight connection at the bilge is obtained as follows:—The
frame is cut at d, D indicates the “margin” plate. It extends fore and
aft the whole length of the tank; its upper edge is flanged at D and
riveted to the tank top plating, its lower edge is riveted to febe bilge
strake by means of a continuous fore-and-aft angle d.
CELLULAR DOUBLE BOTTOM
439
G is a bracket plate inside the tank. It .supports the margin plate
and provides a rivet connection to the floor, the bracket being connected
to the margin plate with the vertical angle bar g.
It will be observed from the figure that this bottom section, consisting
of floors, longitudinals, angles, margin plate, the inside bracket and tank
top, forms an independent unit which if buoyant enough could float
as a watertight tank. Indeed this part of the ship is built flrst and
the frame legs put on afterwards.
The frame and reversed frames are represented by f t and / 2 ; the
frame bar is cut at d, and the reversed frame is bent and riveted
along the top edge of “tank side” bracket H. The bracket is connected
to the margin plate by means of the vertical angle fa all as more clearly
illustrated in Figure 20.
Cellular Double Bottom. —Figure 21 illustrates the transverse floor
of a cellular double bottom, abbreviated to C.D.B. This system
of construction has superseded the McIntyre tanks where water ballast
is carried for practically the whole length of the ship. The C.D.B.
is an integral part of the structure, and being well below the neutral
avia of the ship adds considerably to the strength and rigidity of the
vessel. It also increases her safety by providing a more substantial inner
bottom to resist water pressure in the event of the outer bottom being
punctured by stranding than in the case of the tank top plating of the
McIntyre system. The Board of Trade measures the depth for tonnage
to the inner bottom plating only, thus reducing the measured volume
44:0 NICHOLLS’S SEAMANSHIP \ND NAUTICAL KNOWLEDGE
as compared with a single bottomed ship and relieving the owner of
certain charges which are levied on the registered cubic capacity of
the ship.
The main feature of a C.D.B are indicated in the figure.
A is a continuous centre line longitudinal girder, Oj and a 2 being
continuous double angles connecting its upper and lower edges to the
inner bottom plating and to the flat plate keel respectively.
B is an intercostal side girder, its ends being connected to the
floors by vertical angles b z , and its top and bottom edges to the inner
and outer bottom plating by the intercostal angles \ and b 2 respectively.
The floor plate F is continuous from the centre girder to the margin
plate, having a stiffening angle f x on its top edge, which also provides
the rivet connection to the inner bottom plating D; and the stiffening
/ 2 » which is shown joggled in our drawing, on its lower edge, to
provide a rivet connection to the outer bottom plating. A short
vertical angle / 3 connects the inner edge of the floor to the centre girder,
and / 4 connects its outer edge to the margin plate C.
C is the margin plate forming the side boundary of the inner bottom;
its top edge is flanged and riveted to the inner bottom plating. This
bottom part of the vessel is constructed first and forms a perfectly
watertight unit. The frame legs are placed in position as the work
progresses. The frames, in the figure, appear to be of bulb angle
section which forms a rib just as efficient as the frame and reversed
frame section; it saves the labour and expense of having to bend the
reversed frame to exactly the same curvature as the frame and then
riveting the two together; it is easier to clean and paint, thus keeping
down corrosion, and the bulb stiffens the edge of the frame just as
effectively as a reversed frame.
The tank side bracket E is riveted to the frame as indicated by the
dotted line; the top edge of the bracket plate is stiffened by a flange
and connected to the side of the margin plate by means of the vertical
angle L C is a continuous angle along its lower edge to connect it to
CELLULAE DOUBLE BOTTOM
441
the strake of shell plating on which it rests The tank side bracket is
really a continuation of the interrupted floor.
The supplementary figure shows in plan the further connection of
the bracket to the cellular double bottom. H is the flange at the toj3
edge of the bracket 64s a “gusset” plate with its edge riveted to the
flanged edge of the margin plate C, with six rivets along its centre
up to the point of the gusset thus connecting it to the horizontal flange
of the angle at H. See also page 598
Lightening holes K are cut m the floor plates to reduce the weight
of material and to allow a free flow of water as well as access for cleaning
purposes between the cells of the compartment. Small drainage holes
are shown at the corners of the floors and a larger one m the tank side
bracket. Water can also pass through a drainage hole at the lower
corner of the bracket. It is in this space, called the bilges, where
drainage water, due mostly to condensation of moisture on the sides
of the ship, collects. The suction pipes leading from the various
compartments to the pumps in the engine-room are usually laid m the
bilges. Portable planks are secured along the top of the bilge space
so that the interior is accessible for cleaning. Access to the C D B. }
however, is only possible through manholes on the top of the mner
bottom plating which, of course, are covered with a door capable of
being screwed up watertight.
Fig 22 —Solid and Bracket Floors.
Figure 22 shows several cells of a (7. D B. C is the centre plate
girder with angles at its top and bottom edges riveted to the flat plate
keel K> and centre plate of inner bottom N.
Q
£42 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
The number and spacing of intercostal longitudinal girders is deter¬
mined by the breadth of the vessel. Two are shown at g and g , which
indicates that the breadth of this vessel must have been between 58 feet
and 70 feet, because one longitudinal only is necessary on each side
of the centre line when the breadth is less than 58 feet. Note the
lightening holes cut in these longitudinals.
Solid floors, S, are usually spaced two or three frames apart with
open bracket floors, B and b , at the intermediate frames. Solid floors
are fitted at alternate frames when the frames are 33 inches apart,
and at every third frame when they are less than 33 inches apart
Exception to this rule applies, however, to the engine and boiler spaces
where heavy weights are concentrated and greater strength is required,
and to the region extending to one-fifth of the vessel’s length abaft the
stem as this part is subjected to heavy pounding when labouring at sea.
F and R represent the frames and reversed frames of the open floors,
and B and b the plate bracket at their inner and outer ends. / and r
indicate the frames and reversed frames at the solid floors. N is the
middle line strake of inner bottom plating and letters n indicate other
eut and in strakes. M is the margin plate with a continuous fore
and aft angle on its lower edge and the short vertical angles at
frame space intervals apart already riveted in position, the lattei
being, of course, to receive the tank side brackets.
In Figure 23 A is a centre girder. B a bracket. C a solid floor.
D, longitudinal intercostal girder. E, bracket. F } tank side bracket.
<?, frame. E, gusset angle. J, inner bottom plating. K, continuous
margin plate wangle.
Web Frames.—A web frame is a specially deep transverse frame in
the form of a built girder. They are introduced where decks have
WEB FRAMES
443
been omitted to obtain clear holds. Ships may be built throughout on
the web frame principle in order to get a clear hold for stowage of cargo
by doing away with a deck and compensating for the loss of strength
by means of web frames spaced about six frame spaces apart. The
web frames when associated with plate stringers form a succession of
strong transverse girders, the ordinary framing forming the necessary
local stiffening between them.
Figure 24 (i), (ii) and (in) represent three views of a web frame
of earlier construction associated with a deep stringer; the lettering
indicates the same part in each drawing, (i) is the web frame looked
at from aft; (ii) is the web frame crossed by the deep stringer plate as
viewed from inside the ship and looking transversely; (iii) is a plan
looking downwards. The web plate is connected to the shell plating by
frame angle bar c m (i) and (iii), and stiffened on its inner edge by
double angles 6 (i) and (ii).
The stringer plate d (ii) and (iii) is the same depth as the web frame
plates between which it is fitted intercostally, the ends of the stringer plate
being riveted to the web of the frame by short angles h (i) and (iii) and
the edge of the stringer against the shell plating is united thereto by
short chock angles g (i) and (iii), fitted between the ordinary frames,
the plate being notched to fit round the frames as in (iii).
The inner edge of the stringer is stiffened by double angles e (ii)
and (iii), and the junction of the web frame and stringer plate is strength¬
ened by means of a diamond plate Jc (i), (ii) and (iii), which is riveted
to the stiffening angles on the inner edges of the web frame and stringer
plate. See also figure 5, page 600.
A fore-and-aft angle f (i) and (iii), on the under side of the stringer,
gives a further rivet connection to the reversed frames.
The depth of the web frame depends on the depth of the .vessel,
and in cases where the stringers are deep they are supported between
the web frames by brackets which may be fitted at alternate frames*
444
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Rivets. —There are several forms of rivets named according to the
form of their heads and points. In Figure 25 A and B are called “snap”
head rivets, A having a “snap” form of point and B a “flush” point.
Rivets G and D axe “pan” heads, C having a snap point and D a “boiler”
point, which, it will be observed, is more conical in shape than the flush
point of rivet B. The boiler point is considered to be a better holding
rivet than the others owing to the greater amount of hammering
required to get it into shape, thus filling up the rivet hole more effectively.
Snap point riveting is done with a machine, flush and boiler points are
hammered up by hand. E is a “tap” nvet used in places where a
through rivet cannot be fitted. A screw hole is tapped into the casting,
the tap rivet is then screwed into position by means of the square head
which, having served this purpose, is then cut off.
Fig. 25.—Forms of Rivets
lliret Holes are punched in plates by means of a punching machine
v inch makes a hole of conical form, being smaller on the side into which
tile punching tool first enters. Rivets are, therefore, “made of slightly
conical form under the head to effectively fill up the hole. Plates are
punched from their “faying” surface, faying or facing being the sides
of the landings which bear against each other. Thus, in Figure 25, the
top plate has apparently been punched upwards and the lower plate
downwards; the two plates have then been placed together, the rivets
put in downwards as indicated by the dotted shape, and their points
hammered up by hand into flush or boiler point; or, in the case of the
snap point, with a hydraulic machine.
The Diameters of rivets vary with the thickness of the plates to be
riveted. In shell plating a f-inch rivet is generally used for J-inch
plates.
The Spacing of a row of rivets varies with different kinds of work.
It is expressed in terms of the diameter of the rivet. The space
between their centres may vary between 3J diameters in plating where
watertight and oiltight work is wanted to 7 diameters in the case of
riveting frames to shell plating.
The term “Pitch” is commonly used to indicate the spacing of the
RIVETS AND RIVETING
445
rivets, measured from centre to centre. In cases where the rivets are
31 diameters apart their pitch is said to be diameters.
The ends of plates may be connected by a “lap” joint, which is just
the end of one plate overlapping the end of the other with a sufficient
“landing” to take a single row of rivets, or a double or treble row as
may be required. The plate landing is the name given to the breadth of
the overlapping edges of two plates, which, obviously, would be regulated
by the numbers of rows of rivets. The figures illustrate “chain”
riveting and “zig-zag” or “reeled” riveting.
Fig 28 —Double Riveted Butt.
The ends of plates may also be joined together by means of a “butt”
strap, which is a plate long enough to cover the breadth of the plate
and broad enough to take the requisite number of rivets. There ate
446
NT©HOLLS*S SEAMANSHIP AND NAUTICAL KNOWLEDGE
single riveted butt straps, also double and treble riveted butts as shown
in Figures 28 and 29.
The ends of angle bars are joined by means of a “bosom” piece, or
short piece of angle bar fitting closely into the angles and of sufficient
jssseesesj
Fig. 30.—A Bosom Piece.
length to take at least three rivets in each row on each side of the joint
as shown in Figure 30.
SHELL PLATING.
The system of shell platmg now almost universally adopted
is the “raised and sunken” strake system (Figure 31), the outer plates
being sometimes “joggled” as in Figure 32. A “strake” of plating is
a line of plates.
Raised and Sunken Plating.—In Figure 31, A is the frame, B is the
sunk strake of shell plating resting solid against the frame, C is the
raised strake each edge of which overlaps and rests on the edges of the
adjacent sunk strakes. The overlap at E is called the plate “landing,”
and D is called the “sight” edge of the raised strake; the sight edge of
the sunk strake would be seen from the inside of the ship. F indicates
the position of a narrow parallel “liner” or packing' piece of the same
breadth as the flange of the frame; it is inserted to form a solid foundation
for the raised strake to rest against. The landings of shell plating are
always “chain” riveted, that is, the rivets are exactly opposite to each
other as distinguished from “zig-zag” riveting. (See Figures 26 and 27.)
PLATING
447
Joggled Plating has been introduced to save the. expense and
weight involved in fitting liners. Figure 32 illustrates the “ double ”
joggled system whereby each edge of the outer strake, C 9 is bent
Fig. 31.—Praised and Sunken Fig. 32.—Joggled
Strakes. Plating.
into a joggled shape to form a landing to rest on the edges of the
two adjacent strakes B> the joggle being deep enough to allow the
intermediate part of the outer strake to lie solid against the frame.
Fig. 33.—Deck Plating.
Sometimes the “ clinker ” system is adopted for deck plating as in
Figure 33, which indicates plate B with one edge under the right hand
448 NICHOLAS SEAMANSHIP AND NAUTICAL KNOWLEDGE
plate C, and the other edge on top of the left hand plate A. This
necessitates the fitting of a “ tapered ” liner to fill the triangular
space between the flange of the beam and the under side of plate B.
The sight edges in this system all face the one way, and it has an
advantage over the raised and sunken strakes for deck plating, as
water drains readily to the scuppers as there is no sunken strake for
it to lodge in.
The iraised and sunken, or outer and inner, system of plating
with a parallel liner below the raised strake D is also shown.
A Stealer strake is introduced in the shell and deck platings
towards the ends of the vessel when, owing to the reduced breadth of
the plating, two strakes may conveniently be merged into one, the
single strake being called a stealer, as each time it is fitted the
number of strakes is reduced by one.
ABC D E
Pig. 35.—Angle and Beam Sections,
Figure 35 illustrates the rolled sections most commonly used in
ship construction. A> B, C and D are rolled sections, that is to say,
they are made in one piece ; E, F } and 0 are built sections.
A is a bulb angle used for frames and beams ; B is a channel
section bar ; C is a light section used as stiffeners on bulkheads, etc.;
PLATING
449
bulb section used for beams; E is a built beam section introduced when
a wood deck is laid over the beams, or wherever an extra strong beam
is required; F is a heavy section introduced where great strength is
required, a centre keelson, for example, and in the way of engine and
C>
D E
Fig. 36 —Wood Deck Butts.
boiler spaces; G is a semi-box beam formed by riveting a plate to two
adjacent beams, thus binding them together and merging both beams
into a single girder. See also page 597.
Planking.—Figure 36 illustrates beam sections showing also how the
ends of deck planks are butted and bolted to the beams. A hole is bored
through the plank to take a galvanised screw bolt which passes through
a hole in the flange of the beam and is screwed up by means of a nut
on the underside of the beam. The head of the bolt is sunk into the
plank with a thread of oakum round its neck, well coated with white
lead and screwed up by a nut on the underside of the beam. A “dowel”
of wood, also coated with white lead, fills up the enlarged hole over the
top of bolt and the planking is then planed off smooth.
It will be noticed that the planks fit closely at the lower edge and are
slightly apart at the top edge. This is purposely done so that the
oakum may be driven tightly into the wedge-shaped butts and seams
without being forced right through. The seams and butts of deck
planking are “payed,” that is, filled with pitch or marine glue. In the
figure, A is a built beam; B is a rolled section with a plate resting on it
so that the under side of the planking has to be scored out to fit over the
450 NICJHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
plate; and C, D and E are different forms of butts requiring one bolt
only.
Beam Knees.—There are several forms of beam knees as indicated
in Figure 37, A , B , C and D.
A is a “bracket” knee, the simplest and easiest type to make. It
is just a plate cut to the triangular shape as shown and riveted to the
beam and to the frame.
B is a “slabbed” knee. The bulb on the bottom edge of the beam
is chipped off along the dotted line and a piece of plain or bulb plate
welded to the beam and cut to a shape to get the desired depth of
knee for a seven rivet connection to the frame as shown.
C is called a “split” knee. The end of the beam is cut inwards, or
split, along the horizontal dotted line, the lower part is bent downwards
to the shape required and the open space filled up by welding on a
piece of plating.
D is a “turned” knee. The end of the beam is turned down as
shown by the dotted curved line and a piece welded in to square off the
upper comer. The depth of a beam knee, as indicated by x, is at least
three times the depth of the beam and is regulated, together with the
distance across the throat at y , according to the size of the ship and
as set forth in Lloyd’s Rules.
Where cargoes such as chilled beef are suspended from the beams
of decks, which may, at the same time, be loaded with cargo above, the
strength of the beams of such cargo decks is increased and also the
scantlings of pillars.
Pillars, in supporting the deck beams, relieve the sides of the vessel
and the beam knees of considerable .stress, and by shortening the
length of the unsupported span of the beam the introduction of a pillar
leads to a reduction m the size of the beam. In addition, pillars serve
to tie the bottom and top of the ship together and assist to prevent
deformation.
BEAMS AND PILLARS
461
Pillars may be constructed of solid round bars, tubes, channel bars
riveted back to back, four angle bars riveted together, or of various
built up sections.
Their size depends on whether they are closely or widely spaced,
their height and the weight to be carried. Closely spaced pillars are
an advantage structurally but are very much in the way when stowing
Head
cargo, so the modem tendency is to keep cargo spaces as clear of pillars
as possible in order to avoid broken stowage and loss of space. Centre
line pillars are very useful, however, when erecting midship longitudinal
shifting boards for grain cargoes, some ships are fitted with portable
pillars.
The Figures 38 and 39 illustrate methods of securing the heads and
heels of pillars.
452
NICHOlLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Figure 40 illustrates a very clear cargo hold of a vessel having
four massive tubular pillars, one at each comer of the hatchway. The
pillars are associated with a strong overhead longitudinal girder which
distributes the local supporting power of the pillars to the neighbouring
parts of the vessel.
Fig. 40.—The Hold of ah "Isherwood” Ship.
Watertight Plats,— It is necessary to get watertight work where
the frames pass up through a side stringer plate of a watertight deck.
The most common method is to cut the frame at the under side of the
watertight flat so that the stringer plate resting on the beams may be'
(i) Fig. 41.—Watertight Flat.
fitted close against the shell plating and be connected thereto by means
of a continuous fore-and-aft angle bar. The lower end of the next *
section of frame bar is bracketed to the top side of the stringer plate.
BULKHEADS
45a
In Figure 41 (i), A is the stringer plate lying on beam E , with its
connection to the shell strake B by means of the fore-and-aft angle bar
Oj. The frame 0 and the reversed frame D are cut at the beam and
continued again above the deck as shown. The bracket dj is nveted to
the frame and connected to the stringer plate by means of the short
double angles d 2 . The strake B, the continuous fore-and-aft angle a v
and the double angles d 2 are shown m plan lookmg down on beam E
shown dotted in figure (li). See also figure 6, page 601.
Sometimes the frame is continued in order to maintain continuity
of strength and rigidity. The edge of the stringer plate in this case is
notched out in the way of each frame to allow the plate to bear against
the shell plating. The angle bar connecting the edge of the stringer
Fig. 42.—Watertight Flat, Continuous Frames.
plate to the strake of shell plating is made in short lengths to fit between
the frames, the ends of the bar being bent, joggled and shaped to fit
close to the frame bars and to extend inwards a little beyond the toe of
the frame. The vertical flanges at the ends of the short angles meet
each other and are riveted together. In Figure 42, A indicates the frame,
B and B the intercostal angle bars fitted into the bosom of the frames;
the horizontal flange is riveted to the stringer plate and the vertical
flange to the shell plating, the end vertical flanges being riveted together.
Bulkheads axe vertical partitions arranged transversely or longitudin¬
ally to form walls to subdivide the ship into convenient sections for
stores, living accommodation, cargo, etc.
Transverse Watertight Bulkheads, however, enter largely into the
main structure of the vessel, their principal function being to impart
454 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Btrength and to add to the safety of the vessel by subdividing the hull
into self-contained watertight compartments so that in the event
of one or more compartments being flooded there would still be left
sufficient reserve buoyancy to keep the ship afloat. They also
serve to reduce the risks from fire by confining an outbreak to one hold.
The Number of Watertight Bulkheads is regulated by the length of
the ship, but steam vessels must have at least four, a collision bulkhead
placed at a distance of not less than 5 per cent., that is, one-twentieth
of the vessel’s length abaft the stem measured at the waterline; a bulk¬
head before and another abaft the engine and boiler space and an after
peak bulkhead placed in a position to enclose the shaft tubes in a water¬
tight compartment. Additional bulkheads- are fitted with increase
in the length of the vessel. When over 285 feet 5 bulkheads are fitted;
when over 335 feet, 6 are fitted; when over 405 feet, 7; over 470 feet, 8
and over 540 feet, 9.
Watertight bulkheads extend to the shell plating on each side and
from the floor to the upper deck. Such a large area of plating
must be efficiently stiffened, not merely to prevent it buckling under
pressures but more particularly to withstand the great pressure
of a body of water on one side only in the unusual event of the compart¬
ment accidentally becoming flooded through stranding or collision.
The pressure of water would be greatest at the bottom, and so the lower
strakes of plating are mcreased in thickness and the relative thickness
of all the plating depends on the spacing and strength of the stiffeners
that are fitted. The stronger the stiffeners and the closer they are spaced
the thinner may the plating be.
Collision Bulkhead stiffeners are stronger than for other bulk¬
heads and the plating is made thicker to withstand the slashing
of free water should the compartment be laid open to the sea by collision.
Bulkheads make the section where they occur perfectly rigid and
overstrong so that the excessive local strength has to be distributed
by means of brackets to the adjoining membeir of the hull, viz., to
stringers, keelsons, shell plating, deck platmg,etc., and these components
pass it on throughout "the structure and maintain a continuity and
uniformity of strength.
Bulkheads .—Figure 43 illustrates a side view and front view of a
bulkhead. The plating A may be arranged transversely or vertically,
in this case transversely.
B indicates the vertical stiffeners with their top ends bracketed
to the watertight flat above, and their bottom ends to the inner
BULKHEADS
455
bottom plating & 2 - The brackets \ and & 2 Daust extend one beam space
and one floor space adjacent to the bulkhead in order to get a rigid
connection and support.
The vertical stiffeners C above the watertight flat are ol lighter
section.
Watertight connection round the margin of the bulkhead plating
is obtained by a boundary angle a which is riveted to the shell plating
and to the deck plating. The boundary angles are shown dotted in the
figure as they are on the reverse side of the plating, and at the upper
flat it will be noted that the boundary angle is fitted above and below
the deck plating. The edge of the bulkhead plating at the ship’s side
fits in between the flanges of the frame and of the boundary angle
and these are riveted to the shell and to the deck plating although
sometimes only one angle may be fitted. The punching of these
rivet holes introduces a double row of perforations round the
whole girth of the ship thus introducing a source of weakness which
is not fully restored by filling the holes with rivets. The positions of the
transverse bulkheads in a ship fitted in this way may be located by
looking along her sides and observing where the double lines of rivets
appear.
The efficiency may, however, be regained by fitting broad liners
behind the frames connecting the bulkhead to the shell plating instead
of narrow ones the breadth of the frame flange only. These special
456
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
liners fit hard against the inner sight edges and level up the space between
the outer strake of shell plating and the fore-and-aft flanges of the frame
and boundary angles as indicated in Figure 44 where A represents an
outer strake, B the bulkhead liner, C the frame bar, D the boundary
angle, E and E the double row of rivets, and F the bulkhead plating.
Fig. 44.
Watertight Longitudinal Bulkheads are made equal in strength
and have stiffeners equal to those fitted to transverse bulkheads of the
same depth. Midship longitudinal bulkheads when fitted in lieu of
hold pillars, as in Caledonian Monarch , are stopped at the ends of
hatchways.
A Deep Tank to take water or cargo is fitted in many ships abaft
the engine space, and when a second one is fitted it is usually placed
just forward of the boiler space, as this arrangement puts the ship down
in the water on nearly an even keel. Deep fore peak and after peak
tanks for water ballast serve as trimming tanks in addition to increasing
the displacement of the ship when filled.
The construction of a deep tank consists simply of placing a watertight
transverse bulkhead at each end of the compartment, but the locality
must be increased in strength to withstand the internal pressure of
water. The transverse bulkhead in addition to the vertical stiffeners
is further strengthened by horizontal stiffeners the ends of which
are bracketed to stringers.
A centre line division, not watertight, is fitted to take the place of
midship pillars and to act as a wash plate. It is connected to the deck
and to the double bottom by double angles and strengthened by closely
spaced vertical stiffeners bracketed at top and bottom to beams and
floors respectively. Wash plates are also fitted in peak tanks.
Deck beams are fitted at every frame in the way of deep tanks,
the beam knees and side frames being made larger than elsewhere*
BULKHEADS
457
Pillars are fitted in the deep tank between the centre line division and
the ship s side to prevent the deck from buckling under the stresses
which may be set up by the swishing of the water in a slack tank when
the ship is in a seaway. Sometimes specially deep tank girders are
substituted for pillars in order to get a clearer space for cargo. The
girders are connected to the deck beams and when they are deep enough
they serve as wash plates in lieu of the centre line division. Deep ta.nhg
are fitted with watertight hatches, one on each side of the centre division,
the steel plate cover of the hatches being clamped and screwed down
OOUBLE BOTTOM. CELLULAR DOUBLE BOTTOM.
Fl g. 45. Fig. 46.
_?_ E
- TS'T-T » TW r
. \s' O\\\\vv O' \
iwww
wife;
I
DEEP TANKS ‘AND
CELLULAR DOUBLE BOTTOM.
Fig. 47.—Note the Small Watertight Hatches in ’Tween Decks.
tight on their coamings with screw bolts and made effectively watertight
by packing. See also page 603.
Various water ballast arrangements are shown in the foregoing
illustrations, the hatched lines indicating water.
HATCHWAYS.
Cargo Hatches in ships engaged solely in carrying cargo are made as
large as possible to facilitate rapidity in loading and discharging. These
large openings in the deck necessitate severing many of the beams
thus reducing very considerably the transverse strength. Beams are
488 NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
also cut at the engine and boiler spaces. Refer to the deck plan of
Caledonian Monarch and note the gaps made by the hatches in the upper
deck which, of course, are repeated in the lower deck.
The Hatch Openings not only weaken the vessel structurally but
also affect her seaworthiness unless every precaution is taken to restore
the lost strength by means of additional girders either permanent,
portable or both, and by brackets, hatch coamings, covers and
tarpaulins to resist the inroad of heavy seas breaking on board.
Half Beams are those that are cut to provide the hatch openings.
They are fitted to every frame, their inner ends being secured to the
lower edge of the hatch coaming by angle lug pieces, one flange of which
is riveted to the coaming and the other to the beam.
The Coamings of upper deck cargo hatches should have a minim urn
height above the deck of 2 feet and be stiffened all round the upper
edge with angle bars and half round sections. The lower edge extends
a little below the bottom of the beam and is usually rounded ofl (as
shown in Figure 48) to take away the sharp edge.
The inner ends of the cut beams are supported by pillars spaced
not more than four frame spaces apart, but should this arrangement of
pillaring be departed from the coaming must then be bracketed to the
deck when it is over 15 feet long. The deck plating is doubled at the
hatch comers. Rounded comers are more graceful in appearance and
stronger than square ones, as the coaming plate is then continuous all
round the hatchway instead of being joined by an angle bar. An angle
bar connects the deck plating to the side of the coaming and ensures a
watertight fit.
Portable Hatchway Beams are fitted inside the coaming to form a
framework for the wooden hatch covers to rest upon and also to restore
some of the lost transverse strength due to cutting the beams. The
athwartship beams are spaced so that the unsupported length of hatch
cover does not exceed 4 J feet, with a slight modification in the case .of
hatchways in spaces fitted exclusively for the accommodation of pass¬
engers and light goods. The portable web beams are stiffened at their
upper and lower edges with double angle bars. All hatchway fore and
afters are supported at their ends on a 3-inch ledge formed by steel
carriers fitted to the coamings and to the ends of the portable webs.
The wooden hatch covers are solid and at least 2\ inches thick; the
angles on which they rest are at least 2 \ inches wide.
The Cleats to take the battens and tarpaulins are spaced not more
than 2 feet apart and the end cleats are placed not more than 6 inches
HATCHWAYS
459
from the hatchway comers Battens, wedges and tarpaulins must be
efficient for their purpose and in good condition.
In Figure 48, A is the side coaming, B the end coaming, G is the
portable athwartship web beam with lightening holes in it. and c 2
are double stiffening angles on the web beam, Cg and c 3 are the carriers
on the web beam to support the ends of the fore and afters K and H .
f represents the wooden hatch covers. <z s is a half round* section to
stiffen the upper edge of the coaming plate, a x the angle bar to make a
watertight connection between the deck plating and the coaming. a 2 are
double vertical angles to receive the ends of the athwartship beam,
showing holes to take screw bolts and nuts so that the beam will act
as a tie to bind the sides of the coaming together. d 2 is a cut beam.
Fig. 48.—Hatch Coaming.
Referring to the drawing of the end coaming plate B . we see b 2
the carrier to receive the fore and after K . b 1 is the angle connecting
coaming to deck plating D . is a continuous transverse beam to
which the lower edge of the coaming is riveted, /indicates a wooden
hatch cover resting on the angle bar head ledge a 4 . g indicates the
tarpaulin turned over the comer of the coaming and reaching down
to the cleat < 23 , where it is gripped between the fiat steel batten e and
the coaming when the batten is wedged up tight.
The lower figure represents a portable beam fitted in small hatches
between 10 and 16 feet in length. B is the web plate, and b x and b 2 are
double stiffening angles, and & 3 is a doubling plate. See also page 602.
is the angle connecting the coaming plate A to the deck plating.
a 2 indicates double vertical angles to stiffen the coaming and to
receive the' ends of the athwartship beams. a 4 is a bulb angle stiffener
round the coaming, c represents the wooden hatches, and d a channel
section angle bar placed across the hatch to make the covers more
460
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
secure at sea and to lock up the hatchway in port. The ends of this
bar project a little beyond the coaming and are secured with a clamp
at
The framework of web beams and fore and afters within the coamings
offer a very precarious foothold and many accidents have occurred
through men losing their balance and falling into the hold when taking
off and putting on the sections of wooden hatch coyers and strongbacks.
The modem tendency is to fit steel hatch covers either of the hinged
type to tip up in one piece like a lid, or of the roller pattern which may
be in one piece, or in sections, and rolled back horizontally to uncover
the area of hatchway required. The steel covers are stronger and less
vulnerable to the inroads of heavy seas than wooden covers.
The Stem Bar is a forged bar of iron or steel. It is scarphed to the
bar keel when one is fitted and forms a continuation of the latter. The
connection between a flat plate keel and the stem bar is formed by
troughing, or dishing, the forward end of the keel plate round the end
of the stem bar and riveting both together. The stem is also connected
to the structure by the shell plating, the strakes of which lap on each
.side of the stem as in Figure 49 where A is the stem bar, B and B the
shell plating, and OOa double row of rivets.
Panting is more likely to occur in sharp vessels than in bluff-bowed
•vessels. The curvature of a bluff bow is an element of strength in
itself and helps to resist panting.
Panting Beams are fitted across the interior of the vessel, usually'
on the fore side of the collision bulkhead.
Their strength is distributed over the frames and shell plating by
means of the stringers to which they are connected by brackets, or
gusset plates. Two brackets used together are sometimes called a
gusset. The stringers themselves are sometimes stiffened and widened
where panting might occur. Other parts of the vessel which help
to stiffen the frames and shell plating and thus prevent panting are
PANTING ARRANGEMENTS
461
the chain locker bulkhead, collision bulkhead, floors, breasthooks,
crutches and transom (Figure 50).
Breasthooks and Crutches are horizontal plates fitted at the forward
and after extremities of vessels, and riveted to the ends of stringers and
keelsons on each side, thereby joining the two sides of the vessel together.
They are termed breasthooks when in the bow, and crutches when in
the stem. Breasthooks and crutches are also formed by the junction
of the stringer plates themselves at the ends of a vessel.
Fig. 50.—The Strengthening of the Bows.
The Stern Frame consists of the propeller post and rudder post. These
two important parts of a single screw steamer are commonly forged or
cast in one piece, though sometimes they are made in different pieces
- and “scarphed” together.
The body post is made of curved form at the top and bottom where
it merges into the rudder post, the space between the two forming the
screw aperture.
In large screw steamers the body post is also extended above the
462
NICHOLAS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
screw aperture to a deep floor above the lower deck, to which it is
strongly attached.
The rudder gudgeons are 4 to 5J feet apart, according to the size of
the vessel.
Fig. 51.—A Stern Frame.
In Fig. 51, A is the palm on the extended body post for connecting
frame to floor plate and transom plate; B is the arch piece, scarphed to
body post and to the stem post at C . D is the propeller shaft boss.
E the body post. 3 is the sole piece, the end of which extends forward
and is connected to the hull by dishing, that is bending and shaping,
the keel plate against the sole piece to which it is riveted. The stem
frame and ite connections are made strong in order to counteract
the strain caused by the vibration and continual working of the
propeller.
STERN FRAMING
463
The Transom Frame is the aftermost frame in the ship, and the
“transom floor,” which is at least times the depth of the midship
floor, or 6 times the thickness of the stem frame, is connected to the
stem post by means of an angle bar on each side of it. The shorter
pieces of frame which support the overhanging counter of an elliptical
stem are called “cant frames,” they radiate from the transom and
are bracketed to the transom floor. The outer ends of the cant beams
are kneed to their respective cant frames.
Fig. 52.—Stem Framing.
By permission. From Truck to Keel (Captain H. Paasch).
1. Keel
2. Propeller post
3. Boss of propeller post
4. Arch-piece of stem frame
5. Stem post
6. Rudder gudgeons
7. Sole-piece of stem frame
8. Stem tube
9. Transoms
10. Cant frames
11. Frames
12. Reversed frames
13. Floors
14. Deep floors
15. Keelson
16. Bilge stringer
17. Side stringer
18. Upper deck beams
19. Mam deck beam
20. Lower deck beam
21. Panting beam
22. Stuffing box bulkhead
23. Horizontal bulkhead stiffener
24. Screw aperture
25. Shaft hole of propeller post
464
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
RUDDERS.
The most common form of rudder in vessels of moderate speeds is
the ordinary Single Plate Rudder which turns about an axis at its forward
edge, the hingeing arrangement being in the form of round “pintles”
attached to the “stock” of the rudder whichshipinto “gudgeons” which are
part of the rudder post. The weight of the rudder is taken by the bottom
gudgeon of the stem post into which the lower pintle, the “bearing”
pintle, fits. The end of the bearing pintle is rounded and bears on a
hemispherical steel disc placed in the gudgeon socket, the purpose being
to reduce the area of the metal to metal surface and so minimise friction.
When this disc gets worn it is replaced by another when the vessel is in
drydock.
Kgure 53 shows the stock A, the arms B ) and the pintles C, of a
small rudder before the blade is slipped into position, the arms being
on alternate sides of the blade.
Figure 54 illustrates the detail of a single plate rudder* A, the rudder
blade, the forward edge of which fits into a narrow keyway
scored down the after side of the rudder stock C. B x to B 5 , the arms
which are shrunk on the stock C at b. They are also shown in plan,
Figure 54 (3 and 4), the lettering indicating the same parts.
RUDDERS
465
D is the upper part of the rudder stock E , a horizontal coupling
connecting the two parts of the stock together by means of six screw
bolts and nuts shown m plan, Fig. 54 (2). The purpose of the coupling
is to be able to disconnect the rudder when necessary. F 1 to F 5 are
the pintles. F % is the locking pintle to prevent the rudder jumping
out of the gudgeons when the vessel pitches. It has a head or collar
on the under side of the gudgeon to prevent it lifting.
E g is the bearing pintle resting on the steel disc 0 (Fig. 55). There
is a small hole from the bottom of the socket to the heel of the post,
large enough to take a punch for knocking out the worn disc when
the rudder is jacked up in drydock. H is a hard wood bush of lignum
vitae; J the nut, and K a steel pin fitted to all nuts at the rudder to
keep them from working back.
The top end of the stock is steadied at a watertight flat by passing
through a st uffin g box made watertight by packing screwed down hard
between glands.
Stop Cleats fitted on the rudder or on the rudder post in small vessels
prevent it from going beyond about 38° on either side of amidships, 35°
when hard over being the angle of maximum working efficiency. • In
larger vessels stop cleats or buffers are also fitted on the deck in the way
of the quadrant, but these should stop the rudder at a slightly smaller
angle of helm than the stops on the rudder.
4-66
NICHOLLS’s SEAMANSHIP AND NAUTICAL KNOWLEDGE
kj'n'W/vs^'-Jh—
GEAR
Fig- 69. Fig. 60. Fig. 61.
and the “centre of pressure” exerted by the mass of water impingeing
against it is a point somewhere between the middle of its breadth and the
forward edge. This point alters in position with the angle of helm and
is approximately about one-third the breadth of the rudder abaft the
pintles. Considerable power is therefore needed to turn' it, and so
balanced rudders are fitted in fast ships having large rudders and where
quick rudder movements are required.
RUDDERS
467
A small area of a balanced rudder projects forward of the rudder
post and acts as a partial balance by bringing the centre ot pressure
nearer to the axis and relieving the rudder head of considerable torsional
stress when the helm is put over either way and. of course, reducing
also the steermg engine power required to do so. Balanced rudders
Fig 62 .—An Oertz Streamline Rudder, and Draught Figures.
have greater fore-and-aft length but less height than ordinary, and the
design of the stem post has to be suitable for the type of rudder fitted.
Figures 56 to 61 illustrate various shapes of rudders. In 56, 57 and
58- the pintle shown at the bottom does not support the rudder but
serves only as a steadying piece, the weight being taken inboard on the
stem post. The steering engine in 59 is shown just over the rudder.
468
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
which is an ordinary unbalanced one. No. 60 is a type supported on
a bearing pintle, and No. 61 is a “spade” rudder.
Figure 62 is an Oertz streamline rudder. The part on which the
draught marks are painted is fixed to the stem post and designed to
smoothen out, the confused flow of water thrown against the rudder by
the action of the propeller and the streamlines of the vessel as indicated
in Figure 63, which shows, in plan, the form of the Oertz rudder and the
local flow of water.
The following plates are inserted by courtesy of Submarine Boat
Corporation, Newark, N.J..
Fig. 64,—-The Keel laid on the Blocks.
Figure 64, 0, the centre line keelson; B, vertical angles to take
SHIPYARD PRACTICE
4.69
floors; A, angle bar to secure tank top to keelson; D, angle bars to
secure keel plate to keelson; E> the keel plate*
Fig. 65 —Constructing Floors.
Fig 65 shows construction of floors; A } floors attached to centre line
keelson and angle bars riveted to their upper edges; B 3 lightening hole.
Fig. 66.—A Stage Further on.
Fig. 66, A the intercostal side longitudinals; B 3 the centre strake
>f inner bottom plating which is a sunk strake; C> short narrow liner
>ieces on the reverse angle of the floor to make a level foundation for
he raised strake of the tank top plating.
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
4?u
Fig. 67.—Getting on with the job. First Frame Erected.
Fig. 68.—A Busy Crowd.
CD >
SHIPYARD PRACTICE
471
.Figure 68.. 4. boundary angle bar at bulkhead; B< bolting shell
plating to angle; 0, hole for pipe flange of pump connections- Plate
G is the lower one of a bulkhead.
Fig 1 70 —View Looking Aft.
Figure 70, A s after peak bulkhead; B , side frames at the after body
of the ship; G> bracket plates securing the lower end of the frames to the
tank top. The double bottom extends to the shell plating and there is
no bilge pocket in this type of ship.
472
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Pigure 71, A , beam knee; B , a pillar of H section; C, web frame.
Web frames are sometimes introduced when beams are omitted in
engine and boiler spaces and abreast hatchways in orde^ to compensate
for loss of transverse strength. They consist of a web plate riveted to the
frame and stiffened on its inner edge by two angles. The beam and
beam knees on web frames are of heavier scantlings than those at
ordinary frames.
Note the clips D on the tank top to take the bracket, not yet in
place, for securing the lower ends of the frames.
The Stern Tube.—The propeller post is swelled out to form a boss
for the shaft. The “tail shaft” A passes through the stem tube B , whicl
Fig. 72.—Stem Tube and Tail End Shaft.
carries the bearings C for the shaft to revolve upon. The stem tube is
of cast iron or gunmetal with a flange D on its forward end bolted to the
after watertight bulkhead; the end is fitted with a stuffing box and
gland E to .prevent water entering the ship. The outer end of the stem
Fig. 73 —A Shaft Coupling.
tube passes through the stem post and is secured thereto by a screw nut
F on the end of the tube. The bearings work in strips of lignum vitae
recessed into the bush and kept in position by means of a check plate.
The lubricant is sea water and a drain pipe is led through the bulkhead
STERN TUBE
4:73
with a cock on it to enable the engineer to draw water from the stern
tube, so that its temperature may be tested to ascertain if the bearings
are working cool. A strong massive nut G screwed on to the end o f
the shaft prevents the propeller from working off.
Refer to the profile of Caledonian Monarch and note the stem tube
and the spare tail shaft stowed in the recess at the after end of the
tunnel. To unship a propeller in drydock the nut must be unscrewed
and the propeller slung by tackles hooked on to eyebolts for the purpose
on each side of the ship’s stem. The gland is unscrewed and the tail
shaft uncoupled from its adjoining length of shafting, and which has
Fig. 75—Stem Tube for Side Screw.
also to be removed to allow of the tail shaft being drawn straight forward,
leaving the propeller suspended by the tackles. Repairs and rebushing
of the tail shaft can then be executed.
The other lengths of shafting pass through bearings supported on
widely spaced stools, the forward length being coupled to the thrust shaft
R
474 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
at the thrust block, which takes up the fore-and-aft pressure of propeller
and passes the thrust on to the hull. The bush of the thrust
block is provided with a number of thrust rings, which fit between
corresponding collars on the thrust shaft, the propelling pressure
being exerted on the forward sides of the collars and on the after
sides of the rings when going ahead. The forward end of the thrust
shaft is coupled to the crank shaft, which receives its rotary motion from
the piston rods of a reciprocating engine.
The shaftings and stem tubes for the propellers of a twin screw ship
are arranged in the same way as for single screw vessels.
The shaft abaft the bossing is sometimes supported by one or two
struts as in Figs. 74,75 and 76, but in many ships the shafting is enclosed
by bossing the shaft, in some cases right up to the propeller.
Pipe Line systems for supplying, draining and transferring fresh
water and sea water from and to the various compartments and to
auxiliary engines are fitted in ships, the system being a very elaborate
one in passenger vessels and oil tankers. A drainage system is necessary
to remove by pumps any water which collects in the bottoms, bilges and
tanks. The system usually consists of a main pipe throughout the
BOUNDING PIPES
475
length of the ship, with a separate pipe for bilge suctions, led from the
engine-room forward through the bilges and aft through the tunnel
Auxiliary suction pipes branch oft from the main pipes to the different
water ballast tanks and bilges, the main pipes being led to a valve
chest in the engme room containing the several valves by which com¬
partments and pumps may be so connected that any particular compart¬
ment can be emptied. The valves are of the non-return type to prevent
the possibility of water passing in from the sea, or from water tanks
into cargo and machinery spaces, or from one compartment to another.
Fig 77 —Valve.
Bilge Suction Pipes are fitted with strum boxes or strainers, placed
in accessible positions for inspection when the holds are empty and so
constructed that they can be easily cleared when choked. ' Pipe lines
are fitted with expansion joints or bends so that they may not be
strained or fractured with the working of the ship. See page 604.
Sounding Pipes extending above the load waterline are fitted in each
compartment and ballast tank, with a thick doubling plate under the
bottom end of the pipe for the sounding rod to strike upon. Air pipes
are also fitted at each end of ballast tanks, the caps of which must be
taken oft before the tank can be filled with water.
It is invariably the .daily duty of the carpenter to sound all com¬
partments, tanks and bilges, and to note on a board in the engine-room
the depth of water in each as indicated by his sounding rod. It is also
the duty of an officer on joining a new ship to become acquainted as
soon as possible with the positions on deck of all sounding pipes, hand
pump and sluice valve connections.
In oil tankers the air pipes are led. a considerable distance up the
*76 NTCHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
sides of the mast to carry clear of the deck the vapour given off by
benzine, naphtha, gas-oil or any low flash spirit, and are fitted with auto¬
matic valves winch are operated by the difference of pressure between
the vapour m the tank and the atmosphere outside. When the pressure
in the tank is the greater the gas presses the valve open and escapes
into the atmosphere; and, conversely, when the pressure within the tank
falls sufficiently below the pressure of the atmosphere, especially when
pumping out oil, the valve opens inwards and the air passes into the
tank and maintains an equality of pressure. Needless to say, these
automatic valves require attention and must be opened out and examined
periodically to ensure that they are working properly.
VENTILATION
The ventilation of large passenger ships with several heights of
decks presents a difficulty which is satisfactorily overcome by either
the pressure system or the exhaust system. In the pressure system
fresh air is drawn down the ventilator by fans and forced through sheet-
iron ducts to the various compartments; in the exhaust system, fans
draw the foul air from the compartment and exhaust it up the cowls,
the fresh air entering the ventilatmg ducts.
The Thermotank System is a combination of ventilating, heating
and cooling. The air is drawn by fans into a casing, comes into contact
with the surface of pipes and is rhen forced through ducts to the various
parts of the ship. The temperature of the air may be left as it is, or
heated by circulating steam through the pipes, or cooled by circulating
brine through them.
Engine-room and Stokehold ventilators extend as far down into the
compartment as practical, with branches leading to both sides of the
ship, but fans are usually fitted in the bottom of the ventilators which
extend up to the weather deck. The air is drawn down the ventilator
and distributed as low down as possible, thus displacing the heated air
and expelling it upwards through skylights or other outlets.
Cargo Spaces.—With most cargoes, and especially with those of a
perishable nature, such as fruit, etc., ventilation is an important matter,
and is necessary for the proper care of the cargo and to prevent deteriora¬
tion. The neglect of this may result in the ship being held responsible
for damage if it is proved that such damage might have been prevented
by proper ventilation. When, however, the cargo contains anything
of an inflammable nature, or which is likely to give off inflammable,
VENTILATION
47'
explosive, or poisonous vapour, proper and efficient ventilation becomes
of vital importance, and neglect of this precaution may lead to disastrous
consequences, possibly involving loss of life.
No system of ventilation will be efficient unless arrangements arc
made for the free exit of possible foul, damp, or vapour-laden air, as
well as the introduction of fresh air, the object being to keep a circula¬
tion of air through the entire hold or compartment. Movable ventilators
should be attended to so as to take advantage of the wind. If a hold
or compartment is ventilated entirely by cowl ventilators, they should
not all be turned to the wind. The one furthest to leeward should be
open to the wind; the one furthest to windward should be turned away
from the wind to allow free outdraft. See also page 606*
In fine weather, and when the cargo is not of an explosive or inflammable
nature , such as petroleum spirit , etc., the ordinary means of ventilation
may be supplemented by taking off one or two of the hatches forward
and aft. This will give surface ventilation. In special cases where
additional ventilation is necessary, it can be obtained by rigging wind
sails into an open hatch.
The gas given off from coal cargoes is of a light nature, and rises.
It tends therefore to accumulate at the upper parts of the hold, and by
a system of surface ventilation it will be passed away from the interior
of the vessel. Petroleum vapour, on the other hand, is very much
heavier than air, and thus accumulates at the bottom of holds or other
spaces; and any system of ventilation, when carrying this spirit, to be
effective, should be such as will withdraw the vapour-laden air from the
bottom.
The holds of vessels, other than tankers carrying petroleum and other
similar spirits, should not be ventilated by removing the hatches. Proper
ventilators should be fitted extending to the bottom of the hold. These
should have large cowlheads, the openings being covered with fine
brass wire gauze.
All ventilation of crew spaces should be carefully attended to, and
kept open, when carrying any of these dangerous substances.
No one should be allowed to enter any hold or compartment where
there has been stowed any of these dangerous substances or liquids until
they have been thoroughly ventilated. There are gases which it is
dangerous to inhale, but which are odourless and give no warning of their
presence.
The presence of dangerous gases can be detected by means of a
safety lamp, specially devised for the purpose. If the light becomes
478
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
extinguished the atmosphere is in a dangerous condition. On no
account should a naked light ever be used for trying the atmosphere of any
suspected place .
ISHERWOOD SHIPS.
The vessels described so far have been designed on the transverse
frame systeip, that is, the frames have been closely spaced with widely
spaced heavy longitudinals laid across them. But longitudmal framing,
invented by Sir Joseph W. Isherwood, Bt., and now popularly known
as the Isherwood system, is extensively employed especially in the
construction of oil tankers. The frames in this system are also closely
spaced but arranged longitudinally, the transverse girders being massive
and spaced widely apart, as in Figure 78, which represents a section of
a tanker.
. A, are closely spaced longitudinal frames at the bottom, the sides
and the decks. (
B, middle line longitudinal bulkhead extending from the bottom of
the tank to the top of the expansion trunk.
G, a strong transverse girder consisting of a deep floor plate, a deep
vertical web frame in the lower hold united to a heavy lower deck
beam; a smaller web frame in the ’tween deck is associated with an
upper deck beam of proportional dimensions. Z>, brackets to secure
floor plates and beams to the midship bulkhead; note the longitudinal
stiffeners just showing on the left side of the bulkhead.
ISHERWOOD SHIPS
479
E , transverse bulkhead stiffened by horizontal angle bars, closely
spaced, and further supported by widely spaced heavy vertical stiffeners
F, sides of expansion trunk. The space between this longitudinal
bulkhead and the side of the ship is called the 4 ‘summer” or side tank.
The trunkway, which extends the whole length of each tank, is
about 7 or 8 feet in height and must not exceed m width 60 per cent,
of the vessel’s breadth. *
The Isherwood system lends itself more readily to modifications
in structure to meet special requirements than the transverse system,
especially in offering economy in the work of construction, great longi-
Fig 79 —Isherwood Framing Cargo Vessel.
tudinal strength, convenience in subdividing the ship, and in providing
clear holds for cargo. The rules of the classification societies are suffi¬
ciently flexible to allow of various modifications in the details of ship
construction so that combinations of transverse and longitudinal
framing; web frames, deep frames and ordinary frames; deep and shallow
stringers; rolled section beams and built beams; solid pillars, tubular pillars
and built pillars, etc., may be introduced into various parts of the
same ship. The longitudinal frames of Isherwood ships converge towards
the bow and stem and come too close together so that the transverse
system of framing is introduced at the ends.
480 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNO'VT'LEDGE
Figure 79 is an example of an Isherwood ship for general cargo
purposes, in which longitudinal framing is adopted for the double
bottoms, and decks, with deep frames at the sides and transverse beams
at every third frame Note the vertical stiffeners on the bulkhead
bracketed at top and bottom to the longitudinal frames, and the
tubular pillars at the hatch comers. Tubular pillars have solid heads
and heels.
Corrosion.—When steel is exposed to the action of air, or of moisture,
particularly if it be salt-laden, rust soon appears on its surface which
penetrates into the plating and corrodes it away. Oxygen is necessary
to the formation of rust, hence the reason why it is necessary to
exclude air from direct contact with iron and steel by keeping it well
coated with paint. New ships should be well coated, especially round
rivet heads, butts and laps.
When corrosion sets in all rust must be scaled or hammered ofi,
the bare metal thoroughly scraped, cleaned and dried before applying
a priming coat of paint. Several coats should be given in succession,
allowing sufficient time between each to allow the previous coat to
dry hard.
Sometimes butt straps and plate landings show signs of moisture
and when this occurs the “ weeping ” joints are made tight by cleaning
out the crevices with a wire brush and caulking the edges, which is
just burring up the edges of the plating with a chisel and hammer to
close up the joint.
Paint is composed of two ingredients, a pigment and a vehicle. The
pigment is the solid particles, the vehicle is the oil or liquid portion.
The principal pigments are white lead, zinc oxide and red lead; the
principal vehicles used on board ship are linseed oil, turpentine and
varnish. Linseed oil is a drying oil and turpentine is used for thinning
out. Driers are used to expedite the drying of the paint. The drier
acts on the oil but not on the pigment, and too much drier causes the
paint to crack and peel off. Copal varnish is mostly used for woodwork.
Red lead is supplied as a dry powder. It is a very good first coating,
is strongly adhesive, sets hard and dries quickly. The following quan¬
tities will make up 1 gallon of mixed paint ready for application, its
covering power being about 50 square yards:—20 lbs. red lead; 5 pints
linseed oil; 2 gills turpentine; 2 gills drier.
White lead produces a hard layer and is used as an undercoating.
It has more body than white zinc, which is a thinner and lighter pigment
and retains its pure colour better than white lead. White zinc is used fox
CORROSION AND PAINT
481
suitace decorative work. These paints are supplied ground in oil so
that, on board ship, it is only necessary to add linseed oil and stir well
to reduce it to the desired consistency; add a small quantity of driers.
It works out as a rule that 1 quart of oil reduces 6 lbs. of paint to a
suitable consistency having an average covering power of 50 square
yards. The pigment settles to the bottom of the pot and so must be
stirred with a stick at frequent intervals during painting operations.
When the job is finished any residue of paint should be poured back
into the container and the pot wiped out clean to be ready for next
time, otherwise, skins quickly form on the inside of the pot if paint is
left in it.
Brushes should be rubbed out as dry as possible and put in water
overnight, but if they are not to be used again for some time they
should be washed out in hot water and soap. Varnish brushes should
be put in linseed oil to keep them soft. All brushes when stored away
should be hung up or laid flat and never left standing on their bristles.
Bottom Compositions.—Underwater paints are applied in dry dock.
They are classed as anti-corrosive, anti-fouling and boot-topping.
They are expensive paints, specially manufactured with heavy pigments
which settle rapidly and have to be kept stirred continuously during
application, and a quickly evaporating vehicle which causes the paint
to dry almost as quickly as it is put on. The job has to be done quickly.
Anti-corrosive is first applied to act as a foundation and as an
insulator to prevent the destruction of the steel. The plating must be
first freed from grease and scum as the paint will not adhere to a greasy
surface and will soon flake ofl.
Anti-fouling is coated over the anti-corrosive, its purpose being to
retard marine growth, barnacles and grass mostly. Anti-fouling com¬
position consists largely of oxide of mercury, and if it comes into contact
with the bare steel it will set up corrosion, hence the needof an anti¬
corrosive as an insulator. Anti-fouling coating is usually carried up to
the light load line only and a cheaper paint, called, boot-topping, applied
between the light and load water marks when the ship is afloat.
The cellular double bottoms, inside of tanks, are usually coated
with a layer of cement deep enough to cover the rivet heads
(mixture—two parts sand to one of cement), then cement-washed
occasionally. See also page 613.
Wetted Surface.—The area of the underwater form of a ship is
given by the equation :—W S=L (1-7 d+CbxB) where
m
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
W S is the skin surface area
L the length of the ship
d the mean draught
Cb the ship’s block coefficient
B the breadth
This equation is used in some calculations dealing with the frictional
resistance offered by the surface area of the under water body of a
vessel. It may also be used to estimate the quantity of paint required
to cover an area of shell plating from a given draught downwards
by dividing this surface area by the known covering capacity of the
paint.
The coefficient of a vessel is not always known and in such cases
the manufacturers of special paints adopt empirical equations based
on the "results of experience and the average covering power of their
own products, when they wish to estimate the quantity to send to the
dry dock. Here is one such equation:—
Cwts=Z expressed in square yards and divided by 350
square yards per cwt.
Such equations can only give a rough approximation as the covering
power of patent compositions depends upon the < consistency of the
paint, the temperature, the manner in which it is applied and the
character of the coated surface. Allowance has also to be made for
considerable waste owing to the awkwardness of working under the
ship and the haste due to the economic urgency of getting .the vessel
out of dry dock as quickly as possible.
Example .—Ship 400 ft. long, 54 ft. beam, block coefficient=*8.
Find the amount of antifouling composition required to cover the
bottom up to 15 ft. draught, assuming that 1 cwt. of composition
covers approximately 3000 sq. ft.
(i) WS=L (1*7 d+CbxB)
=400 {(1 -7 X 15)+( -8 X 54)}
=400 (25-5+43-2)
=27,480 sq. ft.
A 27480
.-. ewts. — 30Q p
9*16 cwt.
(ii) Surface Area = L {B+d)
= 400 (69)
= 27,600 sq. ft.
27600
cwts. =
9*2 cwt.
Scantlings. —The term “scantlings” often appears in descriptions of
ship construction, and it would be as well to clear it off here by defining
“scantling” as the term used to indicate the sizes of the different compon¬
ent parts of a ship. The sizes are given in the Rules and Regulations ol
SCANTLINGS
483
the Classification Societies, against the scantling numbers of the ship,
in the form of a senes of Tables which give very precise information
regarding the structure. The Tables are not of much interest to anyone
other than those responsible for the building of the ship, nevertheless
they illustrate to the casual reader the scientific basis underlying the
design and construction of a ship, and, incidentally, they impress us
with the fact that no one has a free hand to build a merchant ship in
any way he fancies.
The numerals are derived from the dimensions of the proposed
ship, the bigger the ship the bigger will her numerals be and the heavier
will be her scantlings. The depth D of the proposed ship regulates
the spacing and the sizes of the side framing and the dimensions of
the floor plates. The numeral D is qualified by another number
referred to as d when entering the Tables, d being the vertical depth
at the middle of the ship’s length measured from the top of the
beams at the side of the lowest deck down to the top of the floors, or
to the top of the double bottom.
The “First Longitudinal Numeral” is length X depth (LxD), and
this number regulates the sizes of all the components forming the
double bottoms also flat plate keel, shell plating, propeller boss plates,
etc. The “Second Longitudinal Numeral” is Lx(B+D), that is
breadth added -to depth and multiplied by length. This number
regulates the scantlings of the topside structure, such as sheer strake,
stringer plates, deck plating, etc. See also page 542.
The dimensions of Caledonian Monarch are length between per-
pendiculars 430 feet, moulded breadth 56 feet, moulded depth
30 ft. 6 in. •
Her numerals would be D = 30*5
First numeral L X D = 430 X 30-5 = 13115
Second „ L X (£+X>)=430x(56+30*5)=37195
The Tables give also the scantlings for bulkheads, masts, rigging,
anchors and cables and the general equipment of the ship.
Shipyard workers and draughtsmen refer to the Tables as required
and do not attempt to memorise the contents of the fifty-six Tables
given in the Regulations, but they may remember from daily experience
and repetition work some of the relative dimensions of the more
important parts of the structure they are working on.
484 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
QUESTIONS.
1. Describe the different stresses a ship is subjected to when she
is working in a seaway.
2. What stresses would be experienced when the ship is (a) pitching
into a head sea; (b) rolling heavily in a beam sea?
3. Name the parts of a vessel specially designed to take up (a)
longitudinal stresses; (b) transverse stresses; (c) racking stresses.
4. What faulty distribution of cargo would produce (a) hogging;
(b) sagging; (c) collapsing stresses?
5. WTiat is meant by “panting”? What parts of the vessel are
most subjected to panting and what structural arrangements are made
to resist it?
6. Name the several components of (a) transverse framing; (6) longi¬
tudinal framing.
7. Which is the most important item in a vessel’s structure, and
why?
8. Sketch and describe (a) a bar keel; (b) a flat plate keel. State
why the latter is preferred.
9. What is a “floor?”
10. Show by means of a sketch how a frame, and reversed frame,
are connected to a floor plate.
11. Describe any sections, other than frame and reversed frame,
used for transverse framing.
12. How are transverse beams connected to the heads of frames?
13. Sketch several forms of beam knees.
14. What is the function of a pillar?
15. Describe a centre plate keelson and state why it is built excep¬
tionally strong.
16. What is a (a) a rider plate; (b) a foundation plate; (c) a lug piece?
17. Show by a sketch how a watertight connection is made between
the stringer plate and the shell plating at a weather deck.
18. Are all strakes of shell plating the same thickness; if not, how
do they usually vary?
19. What is a McIntyre tank? Show by a sketch its general
construction.
20. Why is the cellular double bottom system of construction
preferred to the McIntyre system?
QUESTIONS
485
21. Sketch a C.D.B. and Indicate particularly how watertight
connection is made at the bilge.
22. What is (a) a longitudinal; (b) margin plate; (c) tank side bracket;
(d) gusset plate?
23. What arrangements are made to allow water to flow from one
transverse section to the nest?
24. When and where are web frames introduced?
25. Show by a sketch the method of uniting a web frame and
stringer at their crossing.
26 Show by sketches how two plates are riveted together.
27. Sketch (a) a lap joint; (b) a butt strap joint.
28. What is zig-zag riveting and chain riveting?
29. Describe with sketches the usual system of shell plating.
30. What are the disadvantages and advantages of the “joggled”
and the “out and in” systems 2
31. What is the disadvantage of the clinker system of deck plating?
32. What is a stealer?
33. Sketch and name some of the girder sections used in ship
construction.
34. Mention the names of different kinds of rivets and illustrate
them by sketches.
35. What are the functions of a pillar? What are the structural
advantages and the commercial disadvantages of pillars in a cargo hold?
36. Sketch some forms of heads and heels of pillars.
37. How is a deck fiat made watertight at the ship’s side (a) when
both frame and reversed frame are severed; (5) when the frame is
continuous?
38. In what manner do bulkheads contribute structural strength
and safety to a vessel?
39. What minimum number of watertight bulkheads is fitted in a
steamship and what are their special functions?
40. How is bulkhead plating stiffened and how is it connected to
the shell plating?
41. A stringer is cut at a bulkhead, what method is adopted to
maintain the strength at the juncture?
42. What is the advantage of having longitudinal bulkheads in
cargo spaces?
486 NICHOLES* S SEAMANSHIP AND NAUTICAL KNOWLEDGE
43. What is a “deep” tank?
44. Describe the special structural arrangements of a deep tank,
45. Can deep tanks be completely filled with water by the same
method as D.B. tanks; if not, what may the reason be?
«
46. The cargo has just been discharged out of a deep tank, describe
exactly what should be done before the order is given to fill it with
water.
47. What are the structural disadvantages of hatch openings?
48. Describe a method whereby hatch coamings are stiffened and
strengthened.
49. How is loss of strength due to cutting transverse beams in
way of deck openmgs restored?
50. What are half beams? How, and to what are their inner ends
connected?
51. How is a watertight connection made between a hatch coaming
and the deck plating?
52. Sketch an arrangement of portable hatchway beams and fore
and afters.
53* In what way do hatch openings affect the seaworthiness of a
vessel in bad weather?
54. How is shell plating connected to the stem bar?
55. Describe a method of stiffening the bow of a vessel to resist
panting.
56. What are “breasthooks,” “crutches,” “panting beams?”
57. Sketch the stern frame of a steamship and name its different parts.
58. Where are the transom frame and the transom floor?
59 What are cant frames and cant beams?
60. Sketch the outlines of an elliptical stern and a cruiser stem,
and state the advantages and disadvantages of each.
61. Describe a single plate rudder and how it is supported.
62. What takes the weight of the rudder? What is considered to
be the angle of maximum steering efficiency and what prevents the
rudder going beyond that angle?
63. What is meant by the “centre of pressure” of a rudder and where
about is it situated?
64. Describe some forms of rudders and state some of the advantages
claimed for them.
QUESTIONS
487
65. Describe the stem tube of a steamship and how water is
prevented from entering the ship.
66 How is the tail end shaft lubricated ?
67. How is a propeller unshipped in dry dock?
68. How is the thrust of the propeller communicated to the ship’s
hull?
69. Describe the bilge and tank drainage system of a vessel you
have served in.
70. Who controls the inlet and outlet valves of tanks and bilges,
and where is the valve chest usually placed?
71 What are strum boxes and what precautions must be taken with
them?
72. Why are long pipes m a vessel not usually straight throughout
their length?
73. How is the depth of water in the various compartments
ascertained and who attends to this?
74. What should be done before ballast tanks are run up?
75. What special arrangement is fitted to the air pipes of cargo
oil tanks?
76. Describe a system of ventilation adopted in some large passenger
ships.
77. How is the stokehold and engine room ventilated?
78. Describe the special features of a vessel constructed on the
Isherwood principle.
79. What is corrosion and what parts of the ship are most subject
to its effect ?
80. How is steel work prepared before coating it with paint ?
81. Name some of the paints used at sea and state why different
kinds of paint are used for different purposes.
82. What priming coat would you give to (a) bare iron or steel;
(5) new woodwork on deck; (c) the funnel.
83. Give a description of any underwater compositions, the
preparation of the shell plating and method of applying the bottom
coatings when the ship is in dry dock.
84. What is the difference between anti-corrosive, anti-fouling and
boot topping compositions, and state why each is used ?
85. A butt strap on the shell plating shows signs of leaking, what
would you do *
CHAPTER XVIII.
STABILITY, CARGO AND TRIM
LEVERS.
Practical seamanship in many of its branches is an application of
some of the elementary principles of mechanics and hydrostatics.
Every person when moving his limbs intuitively applies some principle
of mechanics either in preserving his equilibrium, overcoming the force
of gravity or moving a weight. The human frame is a machine.
Let us refer briefly to some fundamental notions in mechanics.
The Moment of a force is its power to cause rotation. The simplest
form of schoolroom apparatus for demonstrating the law of moments
is a flat wooden ruler graduated in inches, supported on a nail through
a hole at its centre so that it is perfectly balanced but free to rotate in the
vertical plane about this axis called the Fulcrum (F).
When a 1-lb. weight (W) is hung at a distance of 12 inches to the
right of the fulcrum ( F ), the right hand end of the ruler at once turns
clockwise. The weight (TT) is called the Force, and the distance (F W)
the Arm.
The Moment of the force round the*fulcrum is therefore 12 ins. xl lb.
=12 inch-lbs., or, 1 ft.xl lb.=l foot-lbs.
If a weight (TF 1 ) of 3 lbs. be now hung at a distance of 4 inches to
the left of the fulcrum F, the ruler will turn counter-clockwise and che
488
MOMENTS
489
moment will be 4 ins. X3 lbs. =12 inch-lbs. or 1 foot-lb. Tbe 1 lb.
weight will thus be balanced by the 3 lbs. weight and we have what
is called a system of Parallel Forces. The two forces of 1 lb. and 3 lbs.
acting downwards at W and W 1 respectively are balanced by the
single, but equal and opposite force, acting upwards at F . The nail
at F is supporting a weight of 4 lbs. neglecting the weight of the ruler.
The system is in equilibrium, and all such systems must be so when
the sum of the moments on one side of the fulcrum is equal to the sum
of the moments on the other side no matter how many weights and
distances there may be. The centre of gravity of the system is at the
fulcrum F and may be defined as the single force which is equal but
opposite to the resultant of the given forces.
4
>
W‘ F
w
r i l i i i i I i 1 1
j »_s
n
\
t
3 lbs 10 lbs.
Fig. 2.
Moment=power to turn =arm X weight.
Example .—If a weight (IF) of 10 lbs. is suspended 3 feet from the
fulcrum of a freely rotating rod, where must a 3 lbs. weight (IF 1 ) be
suspended to regain the equilibrium of the system?
Weight IF 1 X FW 1 = weight IF X FW
3 lbs. X F W 1 = 10 lbs. x3 ft.
3 F IF 1 =30 foot-pounds F 1^=10 ft.
Ans .—Place the 3 lbs. weight 10 feet on the opposite side of fulcrum
to the 10 lbs. weight.
When the ruler is supported with its centre of gravity over the
fulcrum the principle is the same and the 1 lb. weight 12 inches to the
right of F will balance the 3 lbs. weight 4 inches to the left of F. We
have here a Lever, the simplest of machines. There are three kinds
490 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
of levers, first, second, and third class. The foregoing illustration is
that of a first class lever by simply substituting the term Power for one
of the weights. The relative positions of the fulcrum, weight and power
determine the class of lever.
In levers of the first class the fulcrum is between the weight and the
power (Figure 4).
Fig 4 —Lever Fust Class
Example .—Tilting up a heavy weight to get a cargo slmg under it.
A man puts his weight of 150 lbs. on the end of a lever 6 feet from the
fulcrum, the other end of the lever 2 feet on the other side of the fulcrum
is under a box. The man is just able to tip the box, what weight is it?
Arm X weight = arm X power
2 W = 6 X 150 lbs.
W = 450 lbs.
The weight of the box is therefore 900 lbs. as half its weight, 450 lbs.,
is supported by the comer resting on the floor, and half is supported
by the lever. *
Example .—A steelyard. What must be the weight or power of
LEVERS
491
the bob on a steelyard, if, at a distance of 12 inches from the fulcrum,
it balances a weight of 20 lbs. at a distance of 3f inches from it?
Arm X power
12 X P
P
— arm X weight
= 3§ X 20
18 20
= 1T X T
= 6
The bob weighs 6 lbs.
In levers of the second, class the weight is between the fulcrum and the
power (Figure 6).
Example —Find the power exerted by a man pulling upwards on
the end of a lever 10 feet long, the other end of the lever is resting on
the ground, 3 feet under and beyond the comer of a box, which weighs
500 lbs.
Arm Xpower=annx weight, but half the weight of the box, 250 lbs.,
is supported on the ground so the man has to lever up 250 lbs. only.
10 ft. X P = 3 ft. x 250 lbs.
P = 75 lbs.
The man exerts a power of 75 lbs. to tilt the 500 lbs. box.
Example. —An oar 12 feet long rests in a rowlock 4 feet from the
loom. Two rowers pull with a power of 100 lbs. each as measured by a
spring balance. Required the propelling pressure or weight acting at
the rowlock.
492
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
The resistance of the water to the movement of the blade is the
fulcrum.
Arm X weight = arm X power.
8 W = 12 x 100, W = 150 lbs.
The propelling force is 150 lbs. on each rowlock.
Fig 7.
In levers of the third class the power is between the weight and the
fulcrum (Figure 8).
Example. Up-ending a ladder. The foot of a ladder is fixed to the
ground, the other end 30 feet up is leaning on a wall with a pressure
Fig. 8 —Lever. Third Class.
of 10 lbs. A man takes hold of the ladder 5 feet up from the foot;
what power must he exert to pull the top end away from the wall?
Arm x power = arm X weight
5 P—30 X 10 /. P » 60 lbs.
The man must exert a pull of 60 lbs.
PARALLEL FORCES
493
Parallel Forces and Principle of Moments.
Example .—Two men A and B are carrying a 10-gallon drum of
fresh water on a 6-ft. pole supported on their shoulders. The drum
is 2 feet from A’s shoulder and 4 feet from B’s. The drum alone weighs
5 lbs., what load is each man supporting?
Fig. 9
One gallon F.W.=10 lbs. Total weight of 10 gallons of water
and drum is therefore 105 lbs..
If the weight were suspended at the middle of the pole (at 3 feet) the
weight would be divided equally between the two men in the proportion
as 3 is to 3, the distance of their shoulders from the weight, but the
weight is nearer to A than to B so, obviously, A*s exertion must be
the greater as the forces are balanced, otherwise, something would
happen. The exertion is in inverse ratio to the length of the arm of the
lever.
Weight borne by A ^ distance of B from weight 4 2
Weight borne by B distance of A from weight 2 1
The exertion of A is twice that of B. Divide the weight into three
parts of 35 lbs. each.
Answer.—B carries 35 lbs.; A carries 70 lbs.
Fig. 10.
We might have applied the principle of moments to this example,
using A*s shoulder as a fulcrum, to find the load carried by B.
494
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Arm Xpower=armX weight, 6xP=2xl05 .\ P —35 lbs.
Conversely, working in the other direction using B y s shoulder as a
fulcrum.
ArmXpower=armxweight 6 xP=4xl05 P—10 lbs.
Answer.—B carries 35 lbs ; A carries 70 lbs.
The Wheel and Axle is an application of the law of moments. A
dolly winch consists of a wooden barrel of small diameter with a turning
handle of larger radius fitted on the end of a spindle through its centre
as m Figure 11, (i), (ii) being an enlarged end section of the winch. The
fulcrum (F) is the spindle, F W is the radius of the barrel, F P is the
radius of the* circle described by the handle, W is the weight to be
lifted, P is the power applied to the handle.
Arm X weight = arm X power
or, FW xW = FP x P
Example .—The radius of the barrel of a hand winch is 6 inches,
the radius of the handle is 18 inches, find what weight will be sustained
by a force of 100 lbs. applied to the handle.
6 ins. XTF==18 ins. X100 lbs. TF=300 lbs., the weight which
could be held in suspension.
Example .—The radius of a capstan is 1 foot, there are 8 capstan
bars each 6 feet long measured from the spindle of the capstan when
shipped. A weight of 2 tons is being heaved in on a single wire, find the
power to be applied to each bar to hold the weight.
F PxP=P WxW, or 6 ft. xP lbs. =1 ft. X 4480lbs .\ P=747lbs,
The power on each bar is therefore 747-f8=93J lbs., neglecting friction.
SYSTEM OE WEIGHTS
495
Fig 12.
A Couple — When two equal and opposite forces act at different
points on a levsr a turning force, called a couple, is introduced which
can only be neutralised by another couple tending to produce rotation
in the opposite direction.
Examples .—Letting go the handle of the winch when the weight
is on, or letting go the capstan bars when the pawls are up; the crank¬
shaft of a reciprocating steam engine; breasting a ship round the comer
of a dock wall, as in Figure 13, where Pis the fulcrum, P the power and W
the weight. In the event of the resistance of the water on the starboard
bow and on port quarter being equal to the turning force of P, then
the couple would be neutralised and the turning of the vessel arrested.
CENTRE OF GRAVITY OF A SYSTEM OF WEIGHTS.
Example —(l) A wooden batten A B, graduated in feet, is supported
at A . A weight of 20 lbs. is suspended at B 8 feet from A. The
moment about A is 8 ft. X20 lbs.=160 foot-lbs. (Figure 14).
496
NICHOLLS’S SEAMANSFTF AND NAT7TICAL KNOWLEDGES
The distance of the centre of gravity (C. of G) of the system from A,
Moment 160
neglecting the weight of the batten, is-
—— =8 feet, which is
Weight
obvious as the weight B could be suspended in equilibrium by a cord G
if the pivot at A were withdrawn.
(ii) Distribution of Weights.—Suspend a 10 lb. weight at C 6 feet
from Ay and another 10 lb. weight at B 8 feet from A. Then moment
about ^4==(6 ft. X10 lbs.)+(8 ft. X10 lbs.)=140 foot-lbs. The bending
moment at A is now 140 foot-lbs. as against 160 foot-lbs. in example
(i), 20 foot-lbs. less, although the total weight suspended by the rod
(20 lbs.) is the same, its distribution, however, is different (Figure 15).
G
A
“F?
iO ioibs
Fig 15.
^ , Moment about A 140 _, .
The C. of G. of the system =- --- -—-—=-—=7 feet from A.
J Total weight 20
ind if the pivot at A were removed the system could be balanced in
equilibrium at G midway between the two 10 lb. weights, which is
obvious when the weight of the rod » neglected.
(iii) Redistribution of Weights.—Suspend four 5 lbs. weights at B, Gy JD
and E y points which are 8, 6, 4 and 2 feet from A respectively. Tbie
moment about A is now ( 8 x 5 )+ 16 X 5 )+( 4 x 5 )+( 2 X 5)=100 foot-lb k
SYSTEM OP WEIGHTS
497
This demonstrates that the bending moment about A is still further
reduced by a redistribution of the total weight of 20 lbs. The C. of G. of the
, . Moment about A 100 ^ n ,
system is——— --— — —— 5 feet, so that the system could be
J Total weight 20
6
A
\ A
£
O ;
c
B
t
_ t - i-
—$- i
* t
_*J
f- ? f j.
Fig. 16.
balanced at the point G, 5 feet from A. Thus an alteration in the
position of the weights alters the position of the centre of gravity
neglecting the weight of the batten.
Note that m the foregoing examples the clockwise moment about G
is equal and opposite to the anti-clockwise moment about the same
point and the rod will not rotate in either direction—it is in equilibrium.
The problem which presents itself on board ship is to find the shift
of the centre of gravity from a given position when weights are added
to, taken from or moved about in the vessel, the method of solution
being the same as in the following co-related examples of a simple rod.
K
Fig. 17.
Example. —(i) Consider again the case of our 8 ft. stick with its
C. of G. at its middle point G when unloaded. If weights of 4, 6 and
10 lbs. be placed 2, 5 and 7 feet respectively from the end E , find the
distance point G has shifted.
498
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Moment about K =(2x4)+(5x6)+(7 XlO)
Distance K G x
=108 foot-lbs
Moment
Total weight
108 * ,
: —=5*4 leer
20
The initial distance K G was 4*0 ft.
The new distance K G x is 5*4 ft
GQ X = 1*4 ft.
The addition of the weights has shifted the C. of G. i*4 leet to the
right.
(ii) Redistribution of Weights.—Suppose the 10 tbs. weight were now
shifted 3 feet to the left, find the position of the new centre ot gravity.
Fig. 18.
Draw Figure 18 for the new condition.
Moment about K =(2 x4)+(4 Xl0)+(5 X6)
Distance K G<
= 78 foot-lbs.
Moment 78
Weight 20
=3*9 feet
K G x was 5*4 feet.
KG 2 is 3*9 „
G 1 G 2 is 1 *5
Shifting the weight 3 feet to the left has shifted the C. of G. 1 *5 feet
to the left.
(iii) Lifting off a Weight.—Lift off the 4 lbs. weight and trod the
shift of the centre of gravity 6r 2 .
Draw Figure 19 for new condition
SHIFT OF CENTRE OF GRAVITY
499
<3a Q»
* *
K U ! 5 ft
l *.i ■■■■ . 1- L - -L- - r ‘ * *
H,
IO 6 443
Fig 19
Moment about E={i xl0)+(5 x6)=70 foot-ibs.
Distance K £?, = — = 4-38 feet
3 16
K G z = 3-90 „
= '43 „
Lifting off the weight has shifted the C. of G. -48 feet or 5-76 inches
to tlie right. *
Note .—Multiply decimals of a foot by 12 to convert into inches.
Example. —(i) Given a rod of negligible weight, loads of 10 lbs. and
5 lbs. are suspended at 2 feet and 8 feet respectively from a point K at
one end of the rod. Find the position of the centre of gravity of the
system (Figure 20).
K
i_L.
to
G
A ^
! 8 ft
-I_!_I_ulu_I
T
S LiS
Fig. 20.
Moment about K =(2 Xl0)+(8x5)=60 foot-lba.
66
Distance K G = — =4 feet •
15
(ii) Adding weights.—A load of 10 lbs. is now suspended 7 feet from
K. find the position of the new centre of gravity (Figure 21).
Moment about K =(2 xl0)+(7 Xl0)-f(8 X5)
„ =130 foot-lbs.
500
NICELOLLS S SEAMANSHIP AND NAUTICAL KNOWLEDGE
130 „ t
Distance K G x = —— = 5*2 feet
25
KG
= 4-0 „
G G 1 -1-2
Adding the 10 lbs. weight has shifted the C. of G. of the system 1*2
feet to the right.
a
£■ D
w
taiiis y
Fig.
A
22
C
Exampte .—A rod of wood AB is pivoted at
A so that it revolves freely in a vertical
plane. A 5 lbs. weight is suspended at B, 8
feet from A, by means of a string over a
frictionless pulley C. What weight must
be suspended at B, 3 feet from A, by a string
through the pulley E to keep the rod per¬
pendicular?
The left hand moment about A must be
made equal to the right hand moment about
A to maintain perpendicularity.
Therefore 3 ft. X W=8 ft. x5 lbs.
3 If=40 .-. W=13£ lbs.
Answer.— 13$ lbs.
EQUILIBRIUM
501
STABILITY
Equilibrium.—When solid objects are supported at their centre of
gravity they are in equilibrium; it may be stable, neutral or unstable
equilibrium.
Take an oblong block of wood as in Figure 23. Draw diagonals on
one of its faces; their intersection gives the axis of its centre of gravity
which, of course, will be situated within the block at its centre. Drive
a small tack in the block at the point where the diagonals cross and
tie the string of a plumb bob to it.
(i) Stand the block of wood on its end It is in equilibrium and
the plumb line bisects the base. The weight of the block acting down¬
wards through its centre of gravity is counteracted by the upward
force of the table and being broad of base the block is firmly established
in stable equilibrium.
(ii) Tilt the block a little to one side. It is supported on one edge,
but it is still in stable equilibrium because, if the tilting pressure of the
hand were removed, it would return to its original upright position as
indicated by the plumb line intersecting the base.
(iii) Tilt the block over a little more until the plumb line passes
through its comer. The block is then in neutral equilibrium, it cannot
remain balanced on its edge but will either return to the upright
position again or topple over on its side when the hand is removed.
(iv) Tilt it over still further until the plumb line lies outside the
base of the block. It will now be in unstable equilibrium and will
topple over on its side.
The block is in stable equilibrium when the vertical line through its
centre of gravity falls within its base, but its equilibrium is unstable
502 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
when the vertical line falls outside the base. The broader its base
the more stable will the block of wood be The same principle applies
to a person who is losing his balance but spreads out his legs to prevent
himself from falling by broadening out his base of support.
The equilibrium of a floating ship is somewhat similar but not
quite the same owing to the difference m the density of the medium
which supports her. The block of wood is supported at the surface
of the table, a ship is supported by, but not at the surface of, the water.
Displacement-Tonnage is the weight of the ship and her contents
in actual avoirdupois tons
Volume of Displacement is the quantity of water required to fill
the moulded shape of the hole left by the ship if she were lifted out of
the medium in which she floats. The weight of the water is equal to
the weight of the ship, but the volume of the water is only equal to
the volume of the underwater portion of the ship. The displacement
may be expressed in convertible terms, either m tons weight or in
measured capacity.
1 ton fresh water =36 cubic feet
1 ton salt water =35 cubic feet
The displacement tonnage can be found by multiplying the product
of the vessel’s length, breadth and mean draft by her coefficient of
fineness; this gives the volume of displacement in cubic feet, and as
there are 35 cubic feet of sea water to a ton, by dividing this volume
by 35 we obtain the displacement tonnage, thus:
Displacement tonnage £ X 23 X d Xcoefficient
in sea water 35
co cfficienf
Fjg. 24.
Coefficient of Fineness.—The coefficient of fineness of a vessel is the
ratio or proportion her underwater form bears to a rectangular shaped
block of the same length, breadth and depth (Figure 24).
It will be realised, therefore, that the finer lines a vessel has the
SHIP STABILITY
503
smaller will be her coefficient. In destroyers, yachts and vessels wneie
great speed is required the coefficient may be as small as *15, whereas
in the bluff tramp class where speed is a secondary consideration the
coefficient is often as great as *S5. Between these two extremes the
coefficient of fineness is adopted to suit the requirements of the vessel.
SHIP STABILITY,
Draw a cross section of a ship with a waterline across it. Mark a
spot G to represent the centre of gravity of the ship which is a point
where the whole weight of the ship and her contents are conceived to
act vertically downwards. Mark a spot B to represent the centre of
buoyancy of the ship. It is the point at the centre of the displaced
volume of water through which the whole supporting force of the water
is conceived to act vertically upwards. It will be the geometrical
centre of the figure W L K.
The downward force at G is equal to the upward force at B. They
are equal and opposite forces acting in the same vertical line when the
ship is at rest. When they are not in the same vertical line something
must happen as the ship cannot remain at rest as she wants, auto¬
matically, to return to her position of equilibrium. In Figure 25 K Gm
the height of the centre of gravity above* the keel, and K B the height
o£ the centre of buoyancy above the keel.
(i) Stable Equilibrium.—Figure 26 represents the same ship forcibly
inclined by an external force such as wind pressure, rolling at sea or by
a masthead tackle led ashore somewhere. The centre of gravity is
504 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
in the same position as before, because we must assume that nothing
m the ship has been shifted as the centre of gravity only moves when
weights are moved and, then, in a direction parallel to the direction
in which the centre of gravity of the weight has been moved.
KG is the same as in Figure 25, but the centre of buoyancy has
moved to the low side of the ship owing to her underwater volume
having altered its shape as indicated by the outlme of the new
W L K } so the centre of buoyancy must now be a spot a little to the
right of the ship’s vertical line at B\
The ship’s weight, indicated by W , acts downwards through G,
the water buoyancy acts upwards through B 1 and its line of action
meets the ship’s vertical line at M. This spot is called the metacentre.
The ship at sea oscillates about a rolling axis which is not fixed but
is situated in the vicinity of her centre of gravity at a point a little above
G. The ship, as illustrated in this figure, is said to be in stable equilibrium
because, when forcibly inclined, she will return to her original upright
position when the inclining force is removed. The horizontal distance
between the vertical lines through G and B 1 increases, within
limitations, as the angle of heel increases, this distance being
represented by the length of GZ in the figure. GZ is called the arm
and, in this example, a righting lever is being exerted.
The two parallel forces, acting on the lever at the two points G and Z,
form a couple which tends to turn the ship upright again. The moment
is, armXweight, or, GZxW, where GZ is the horizontal distance
between the verticals through G and B 1 , and W is the total weight of
the ship. The weight of a ship at any draught can be got from her
Bari' STABILITY
T 505
Displacement Scale. (See plan of QaXe&oman Monarch.) The arm
shall refer to later in greater detail.
(ii) Neutral Equilibrium.—When top weights are placed in the ship
so that her centre of gravity is raised gradually and approaches M , the
arm GZ gets smaller and smaller and disappears altogether when G
coincides with M. The downward force through G and the upward
force through B 1 are then acting in the same vertical line; the lever has
disappeared and the ship is now in a condition of neutral equilibrium.
(iii) Unstable Equilibrium.—When the point G is above the meta¬
centre we have the condition of unstable equilibrium and the arm GZ
operates a capsizing moment. The ship will heel over further and may
probably capsize.
The illustrations show that a ship is in (i) stable equilibrium when
G is below M, a positive G M; (ii) neutral equilibrium when G coincides
with M; and (iii) unstable equilibrium when G is above M 9 a negative
GM .
The foregoing principle of stability applies to small angles of heel
and is referred to as initial stability, which is the resistance offered by
8
506 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
the ship to small inclinations, and assumes that the line of action through
the centre of buoyancy passes through the metacentre. This is practi¬
cally so for small angles not exceeding 12 degrees, but may not be the
case at bigger angles in a ship-shaped body.
Metacentric Height.—We must know, in the metacentric system of
stability, the positions G and M relatively to the keel, or, at least, the
distance between them which is called the metacentric height (G M);
also the angle of heel, called 0, and the weight of displacement of
the ship. The height of the metacentre is assumed to be constant at
a given draught, but the position of the centre of gravity moves up
and down when weights in the ship are raised and lowered with a
consequent decrease and increase in her G M. The arm GZ becomes
smaller with every reduction in the distance G M , and the length of this
arm, as we have been endeavouring to point out, is a determining factor
in the law of moments.
The metacentre acting through Z is the fulcrum, the ship’s dis¬
placement acting through G is the power or weight, and, as before,
armxpower=moment, or, GZxW =foot-tons and expresses the
energy of the ship to return to a position of equilibrium.
Example .—If (rZ=2 feet and weight of ship=5000 tons, the moment
will be 2 X5000=10,000 foot-tons. This is equivalent to a 1 ton weight
suspended at the end of a lever 10,000 feet, nearly 2 miles, long, or,
of 10,000 tons weight at the end of a lever 1 foot long.
When weights are kept low the GM and GZ are big ar>d the ship
is said to be stiff, she is hard to incline, but when forcibly heeled over an
excessive righting moment is brought into operation which brings the ship
upright in a violent manner, making the motion uncomfortable for those
on board and straining the hull unnecessarily. Should the weights
be high so that GM and GZ become very small the ship is said to be
tender, she is easily heeled over and is slow and sluggish in returning to
the upright. She would be quite a comfortable ship at sea if she did not
capsize. The cargo when being loaded should be distributed to produce
a condition between these extremes so that the ship will be of good
behaviour at sea. In theory this is quite simple; in practice, however,
it is more complicated.
’ The metacentric height (G M) is found by actually heeling the ship
in her light condition, that is, with no ballast, cargo, bunker coal,
stores or water on board—just the completed ship with steam up. This
initial G M having been supplied by the builder, also the corresponding
HEELING EXPERIMENT
507
heights of the centre of gravity and of metacentre above the Reel,
provide information which offers a starting o£E point from whi&h the
G M for various conditions of loading may be computed.
THE HEELING EXPERIMENT TO FIND GM.
The displacement of the ship is carefully calculated by the builders
by adding up the weights of all the materials in her construction and
of stores, equipment and any ballast or cargo that may be on board
at the time. Let us assume a displacement of 2000 tons; the ship
should be upright, loosely moored by the head and stem, absolutely
free to incline and the weather should be calm
(1) A known weight, say 10 tons, is placed exactly in the middle
line of the vessel (56-lb. weights are convenient to handle and are
uniform in shape). A cord is fixed to a hatch coaming with a plumb
bob attached to its lower end reaching down into a hold and free to
pendulate across the face of a batten fixed athwartship and divided
into fractions of an inch. The initial position of the cord P Q on the
scale is carefully noted.
(ii) The 10-ton weight is then shifted from the middle line to one
side of the ship and the exact distance the centre of the weight has been
moved transversely is accurately measured, say 20 feet. This gives a
“shift” moment of 10 tons X20 feet=200 foot-tons, or, in general terms.
shift moment, where w is the weight and d the distance it has
been moved athwartships.
The distance, R Q in Figure 30, through which the plumb line has
508
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
moved is measured on tiie batten, also its perpendicular length PQ
This gives two sides of the right angled triangle P Q R from which Z.P,
usually called 0, can be found. Suppose R Q=12 inches and P Q=20
feet then cotangent 0=^-^ = —=20 .\ 0=2° 52' (from N one's
RQ 12 ms
Nautical Tables).
Fig. 30.
The 10-ton weight may then be shifted over to the other side of the
ship and the experiment repeated as a check on the first trial. The
angle of heel is greatly exaggerated in the figure to open out the angle 0.
(iii) The following deduction is then made. It is required to find
the distance between G and M, the positions of which are not yet known.
But G actually moves to G x in a direction parallel to that of the weight
and is therefore parallel to Q R\G X M is parallel to R P and Z_M =/_P
=/_0 so that triangles PQ R and M G G x are similar.
The ship is in equilibrium so her centre of gravity must be in the
same vertical line as her centre of buoyancy and M , by definition, must
be the metacentre.
The shift moment ot G is proportional to the shift moment of w,
that is G G x x W—dxw from which GGy==^^- . . . Equation (1)
where GG X is the transverse shift of G
W the ship’s displacement in tons
d the distance through which the weight w has been
moved
HEELING EXPERIMENT
509
But G M = G G x cot 0, and by substituting Equation (1) for G G t we
d'KW
cot 0, which is the general equation to find the initial
get G M —
GM
W
The information may be written in the form of a question. Given
ship’s displacement during the inclining experiment 2000 tons; weight of
10 tons moved transversely across the deck 20 feet; length of plumb
line 20 feet; deflection of plumb bob 12 inches. Required the GM —
Equation :—G M
dxw
~W
cot 0
240 ins. X10 tons X 240 ins.
2000 tons X12 ins.
24 ms
The metacentric height is 2 feet.
This brief description indicates in general terms the principle of the
inclining experiment, but various adjustments have to be made before
the G M corresponding to the actual light condition of the ship can be
ascertained, because the experiment only determines the G M for the
particular condition of the ship at the time, and the efleet of additional
weights on board and of those yet to come iave to be allowed for.
Example .—In a vessel of 4000 tons displacement it was found
desirable to lower the existing centre of gravity which was 18 feet above
the keel. A tank was filled with 300 tons of water, its centre of
gravity being 2 feet above the keel. Required the new vertical centre
of gravity.
G Gj, =
wxd
HT
Where G G x is the shift of G
w the weight of water in the tank, 300 tons
d the vertical distance between the centres of gravity of ship and
tank
W the displacement after the tank is filled
300 tons x 16 feet , ^ .
G & =-—--=1-1 feet
1 4300 tons
The new V.C.G. is 18—1-1=16*9 feet above keel.
GRAPHS.
Various graphs and curves are used by ship designers by which
irregular areas, positions of centres of gravity and of buoyancy and
other variable elements may be co-ordinated. It is the business of the
shipbuilder to ascertain from the plans of the ship the information
510 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
necessary for drawing such curves and it is the duty of the ship’s
officer to be able to read them intelligently.
We shall illustrate five curves which are associated with the loading
of a ship, viz., curves of displacement, tons per inch immersion, stability,
buoyancy and metacentre.
Displacement and Tons per Inch Curves.—The scale of feet at the
side of Figure 31 is a scale of draughts and against each even foot is
the displacement (weight of ship-(-bunkers and cargo) given in tons, the
displacement in F.W. is given to the left of the draught scale and for
S.W. to the right.
The light load line is 8 feet and at this draught the displacement
of the ship is 3500 tons in F.W. and 3600 tons in S.W.
The load line draught is 20 feet in S.W. and the corresponding
displacement is 10,100 tons. The deadweight or carrying power of the
ship is (10,100—3600)=6500 tons when loading in S.W. The tonnage
at intermediate draughts can be found by simple proportion, but ship
draughtsmen dearly love a curve although the two shown here are
nearly straight.
The vertical lines (ordinates) represent draughts, the horizontal
lines (abscissae) indicate a scale of displacement at the bottom and a
scale of tons per inch immersion at the top, the two curves having been
drawn on the same sectional paper for convenience.
Example .—Required (a) the displacement and (6) the tons per inch
at 12 feet draught.
(a) Find 12 feet on the draught scale and trace along the horizontal
line until the displacement curve is reached, then move "vertically
downwards to the bottom scale and read the displacement in tons.
It is a little less than 5600 tons, say about 5570 tons.
(b) Continue along the 12 feet line to the T.P.I. curve, then move
vertically upwards and read the T.P.I. whi<?h is a little more than 42|,
say 43 tons per inch.
Example .—Required the displacement and tons per inch at a draught
of 17 ft. 6 ins.
Answer .—Displacement 8600 tons. T.P.I. 48 tons.
Curves seldom give results as accurate as the information they are
derived from, and usually on board ship any information desired is
read from the scale, interpolating between the even feet when necessary.
draught
CURVE OP DISPLACEMENT
513
Fig. 31.
512
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
For example, the displacement given
at 17 feet is 8320 tons
• at 18 „ 8900 „
Difference in 12 ins. 580 ,, Diff. for 1 in. is 48*3 T.P.I
„ 6 ins. 290 „
add for 17 ft. 0 „ 8320 „
Displacement at 17 6 8610 „
„ 8 0 3600 „ From Displacement Scale.
Deadweight in S.W. 5010 tons, at a draught of 17 ft. 6 ms.
CURVE OF STABILITY
A curve of suability is one which shows graphically the relative
leverages exerted by the ship to restore herself to a position of equili¬
brium when she has been forcibly inclined by the wind or sea. The
reading of this curve calls for a general understanding of the principles
of stability as already explained.
ABC D
- * ««/ * --
Curvc or Stability
Graph X
Fig. 32.
The figures of the inclined ship show a vessel at different angles of
heel and in each case G represents the centre of gravity of the ship
which is a fixed position unless the weights in the ship are altered.
The whole weight of the ship acts vertically downwards through G as
represented by G W.
B is the centre of buoyancy of the ship and*is the centre of the volume
of the water displaced. It changes its position along with the change
in shape of the underwater form of the ship. The total upward pressure
of the water, which is equal to the whole weight of the ship, acts vertically
upwards through B in the direction B W .
In the successive figures A, B and O the righting arm GZ is pro¬
gressively increased, and the ship has an increasing tendency to return
to an upright position. But in figure D the G Z has disappeared, the ship
is m neutral equilibrium, she is ineit and cannot by her own effort
return to an upright position. Figure E illustrates the ship in a position
of unstable equilibrium, because it will be seen that the downward force
through G and the upward force through B have conspired to produce
a lever GZ which will capsize the ship.
The abscissa is a scale of degrees to represent angles of heel of the ship
and the ordinate is a scale of feet to represent the length of GZ the
righting arm.
To Read the Stability Curve —Fig. A represents the ship heeled to
an angle of 7°. Find 7° on the horizontal scale, move vertically up¬
wards to the curve at A, then horizontally to the left and read off the
length of GZ from the scale. The righting arm or lever is inches
long, or 45 feet. If the weight of the ship were 5000 tons, then the turning
power exerted by the ship to bring herself to an upright position is
5000 tons X 45 feet=2250 foot-tons.
» Figure B represents a heel of 26°. The length oiGZ from the curve
is 2*2 feet, the moment, or turning power, would be 5000 tons X 2 *2
feet=ll,000 foot-tons.
Figure G represents a heel of 46°, the length of G Z from the curve
is about 3*6 feet, the righting moment would be 5000 tons X 3 *6 feet
=18,000 foot-tons. This is the position of maximum effort, for it
will be seen that as the angles of heel increase beyond 45° the ship
becomes more reluctant to return to the upright as evidenced by the
diminishing lengths of the righting arms and, at an angle of about 78°, GZ
disappears and the “range” of the stability curve is complete, for on
heeling beyond 78° the ship will capsize if left to herself.
514
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
METACENTRIC DIAGRAM AND CURVE OF BUOYANCY.
Sometimes, but very rarely, curves of metacentres and of centres
of buoyancy are supplied by the builder They give the heights of the
metacentre and the centre of buoyancy above the keel as calculated for
various draughts by the ship designer.
The vertical scale and the horizontal scale in the figure are equal
and represent the draught of the ship. The diagonal line KY is drawn
at an angle of 45° for convenience in plotting so that the figure K X Y Z
is a square.
The heights of the centres of buoyancy for a series of draughts
having been calculated are plotted as B v B 2 , B 3 , etc., and a curve,
which is almost straight, is drawn through the spots.
Thus E x B x is the V.C.B. for 5 feet draught
E 2 B 2 „ 10 „
B z „ 15 „
The heights of the metacentres above the keel {K M) are also
CURVE OF BUOYANCY
515
k 2 m 2
K Z M Z
calculated and plotted on their respective ordinates, and the curve of
metacentres, which is a bold curve, drawn through the spots.
Thus K x M 1 is the height of the metacentre for *5 feet draught
99 99 10 ),
99 1 ^ 99
The vertical distance between the curves gives the B M at any
desired draught.
Thus B t M x is the B M for a draught of 5 feet
■®2 ^2 » 10 ,,
B z M z „ 15 „
A graph for centres of gravity is never given as the V.C.G. alters
with every re-distribution of the weights in the ship, but if the height
of the C. of G. above the keel (K G) is given for certain definite conditions
of loading then those spots could also be plotted on the metacentric
diagram and the G M recorded for at least those particular conditions.
This information is usually worked out for (1) the light load line con¬
dition; (2) with water ballast tanks filled and a particular quantity and
distribution of bunkers on board.
Example .—The ship’s centre of gravity for the light condition at a
mean draught of 10 feet is computed to be 12 feet above the keel.
Required the metacentric height from the diagram.
Find the 10 feet draught on the horizontal scale; it is at K 2 . Measure
K 2 ff 2 12 feet upwards and this gives the.position of the C. of G. The
vertical distance G 2 M 2 is the metacentric height required. It measures
3 feet from the scale.
Example .—The 0. of G. with ballast tanks and bunkers filled is
computed to be 11 feet above the keel at a mean draught of 15 feet.
Required the GM.
Find the 15 feet draught on the horizontal scale and measure the
height of the metacentre above the keel; it is
K z M z = 14 ft. 6 ins.
K z G z = 11 ft. 0 ins.
G Z M Z = 3 ft. 6 ins. the metacentric height required
CARGO AND STABILITY*
It was pointed out on page 506 that the height of the initial centre
of gravity and of metacentre above the keel for the ship in her light
load line condition is supplied by the builder and that this information
offers a starting off point from which the G M for other conditions of
516 NICHOLLS’S SEAM AIN SHIP AND NAUTICAL KNOWLEDGE
loading may be computed. The procedure is to consult the cargo plan
and ascertain the height of the centre of gravity above the keel (K G)
of each superimposed block of cargo and also its weight. The position
of the centre of gravity (V.C.G.) will be approximately near the middle
line of the block of cargo when it is of equal density throughout. A
simple example will perhaps indicate the principle.
* Fig. 34.
Example .—A vessel’s light displacement is 1200 tons and initial
centre of gravity 10 feet above the keel (K G ). She loads 3000 tons of
coal in her lower holds, the estimated centre of gravity being 14 feet; and
1000 tons in her ’tween decks, the centre of gravity being 24 feet. If
her metacentre at load draught is 17 feet above k£el (J KM), required
her G M when loaded.
Tons
V.C.G.
Moment (foot-tons)
Coal
3000
14 ft.
42,000
»
1000
24 ft.
24,000
Ship
1200
10
12,000
5200 78,000
CARGO AND STABILITY
517
moment
The new C. of G. above K =-—— =
weight
K G 1 after loading is 15 feet
KM „ 17 „
78,000
5200
= 15 feet
G 1 M
2
»»
The figure indicates the positions of the weights and of G and M
relatively to the keel.
In order to associate the idea of the system of cargo weights with
our previous examples of simple systems of moments on a wooden
rod, we could turn the ship, as illustrated, on her side and by conceiving
K L to represent a horizontal rod with the weights suspended at their
respective distances from K the new centre of gravity can be determined
in exactly the same way by summing up the moments about K .
Example .—The displacement of a ship in light condition is 3250
tons, centre of gravity 20 feet above keel, metacentre 22 feet above keel.
Cargo is then loaded as follows:—
Weight of cargo—Tons 1000 1500 1250 1100 900 600 400
V.C.G. above keel—Feet 24 22 21 19 23 25 18
Ft
Tons
.25,
GOO
l
24
l
j. .1909
23.
L 99.9
J27
. J. 5 99
G —
1250
5- -20
k 3250
19
ILQO
Find the new metacentric height assuming K M
to be the same.
Arrange the work as follows.
Weights
V.C.G.
Moments
400 tons
18 feet.
7200
1100
19
99
20,900
G 3250
9)
20
99
' 65,000
1250
99
21
99
26,250
1500
99
22
9*
33,000
900
99
23
99
20,700
1000
99
24
99
24,000
600
99
25
99
15,000
181 .A°°
i
I
I
l
l
K
Fig. 35.
10,000
KG 1 —
moment 212,050
212,050
: 21*2 feet
weight 10,000
K G 1 when loaded=21-2 feet
KM •, =22-0 feet
G 1 M = 0*8 feet=9*6 inches
518
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
At the first port of call the following cargo was discharged. Find
the new G M assuming K M to remain the same.
ft
Tons
Weight of cargo—Tons 400 300
500 600
2d
600
V.C G. above keel—
Feet 20 22
23 24
Weights
V.C.G.
Moments
23
5 0 o
400 tons
20 feet
8000
300 „
22 „
6600
500 „
23 „
11,500
HJ22
- $P9
600 „
24 „
14,400
a--!';
Removed 1800 tons
40,500 foot-tons
From 10,000 „
212,050
Remaining 8200 „
171,550
20.
<
!
400
i
Z^- 171 ’ 550 -
8200
20*9 feet
K G 1 for new condition = 20*9 feet
K n. m „ - = zz-u
Fig. 36. (PM „ =1*1
CARGO PLAN.
Cargo plan (Figure 37) is that of a vessel laden with a cargo from
U.S.A. Given the following information calculate the vessel’s meta-
sTq#hag£ orekuc
Hat MO
MACHIHERT
morons
EToks ISO ms Floor
meal 80 - Figs
WTTtm
Si rats
wmiwc*
800 Tons
WHEAT
158T TORS
8ARLET
\ttsoi> tahx-Empty \mosrm empty i R* FOB rm empt* maor*FMprr
Fig. 37.
centric height. Light displacement 4450 tons, height above keel of
initial centre of gravity 13 feet (K G); the height of metacentre in load
condition 18 feet (KM).
r ‘
Compartment
Contents
Tons
VCG.
Moments
(Foot-tons)
feet
No. 1. Lower
Barley & wheat
942
14
13188
'Tween deck
Apples seed, etc
115
26
2990
Shelter deck
Flour
161
32
5152
No 2. Lower
Barley
1397
14
19558
'Tween deck
Apples, etc.
80
25
2000
Shelter deck
Flour, figs
210
31
6510
No 3. Lower
Wheat
804
14
11256
'Tween deck
Flour, etc.
197
25
4925
Shelter deck
Meal
6
31
186
Deep tank
Wheat
750
16
12000
No 4. Lower
1 Rye
1178
14
16492
'Tween deck
Apples
60
25
1500
Shelter deck
Flour
260
31
8060
No 5 Lower
Wheat
933
16
14928
'Tween deck
Barley
110
26
2860
Cross bunker
Coal
660
16
10560
No 3 D B. tank
Fuel
103
2
206
After peak tank
Water
27
12
324
Ship
C of B.
4450
13
57850
1
12443
190545
KQi _moment_ 190545 __
tons 12443 ~~ °
KM = 18 0
new GM = 27
We have computed the moment for each weight but, obviously,
those having their centres of gravity at the same height above the keel
could be slumped together and so reduce the number of items.
CARGO AND TRIM.
The ship supported as she is by fluid pressure is free to incline in
any direction under the action of forces. The forces acting on the
ship and the effects produced when dealing with inclinations in a fore-
and-aft direction are similar to those just described for transverse
inclinations. In Figure 38 B denotes the longitudinal position of the
centre of buoyancy (L.C.B.) and (zthe longitudinal position of the centre
of gravity (L.C.G.). It should be observed that in any vessel the longi¬
tudinal metacentric height (L.G.M.) is considerably greater than the
transverse metacentric height (<? M) and consequently the ship is very
much stiffer in a fore-and-aft direction than transversely. The ship
will always be stable in a fore-and-aft direction as it is practically
impossible to raise the C. of G. above the longitudinal metacentre.
520
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
The height of the metacentre above the centre of buoyancy is
U
BM =
12 D
Where L is the ship’s length and D the draught tor box-shaped
vessels.
Figure 38 represents a ship tipped by the head by some external
force. B moves to B 1 but the C. of G remains at G as no alteration
has been made in the distribution of weights in the ship. M is the
point where the vertical line through the new C. of B. intersects the
vertical line through the original C. of B. and this defines the longitudinal
metacentre. GZ is the arm of the moment tending to bring the ship
back to an even keel and, as in the case of transverse inclinations, the
moment will be WxGZ.
The draught of a ship is given at the stem and stern and there seems
no particular reason why it should not also be given amidships. The
draught figures are § inches in depth and the space between them
is also 6 inches.
When the draught is greater at one end than the other the ship is
said to be trimmed so much by the head, or by the stem, as the case
may be.
The tipping centre is assumed to be at the middle of the vessel’s
length for approximate calculations involving small changes of trim.
If a weight (w), say 90 tons, be placed exactly over the tipping centre
(T.C.) the ship will sink bodily and, if her tons per inch immersion
CARGO AND TRIM
521
at this draught be 30 tons., the sinkage would he 3 inches forward
and 3 inches aft, thus increasing her mean draught 3 inches.
But if the weight (w), 90 tons, were placed 100 feet before the tipping
centre the vessel would trim by the head and the ship’s waterline W L
would be changed to W 1 L 1 , showing a wedge of immersion forward
Fig. 39.
and a wedge of emersion aft as in Figure 39. Conversely, if the weight
were placed aft the ship would trim by the stem. In order to compute
the change of trim we must know:—
(1) The weight required to alter the mean draught 1 inch, that is
the “tons per inch immersion,” abbreviated to T.P.I. (get used to these
abbreviations as they save a lot of writing). This quantity varies
slightly with change of draught owing to the altering shape of the
underwater form of the ship.
The T.P.I. can be got from the displacement scale.
(2) The Moment to Alter Trim by 1 Inch, or Inch-Trim-Moment,
abbreviated to I.T.M. This information should be supplied by the
builders as it is determined by calculation or by experiment, and it
also varies with the draught.
The following formula gives an approximate inch-trim-moment.
I.T.M.
30 T 2
B
where T = tons per inch immersion as found from the Displacement Scale
B = moulded breadth of vessel
(3) The weight added to, discharged from, or moved about in the
ship and the longitudinal distance of its centre of gravity from the
tipping centre must also be known; then weight X distance ^moment.
Knowing the T.P.I. and the I.T.M. the method of computing the
change of trim may perhaps *be best demonstrated by means of an
example.
Example .—Given T.P I. 40 tons, I.T.M. 1500 foot-tons, draught
12 ft. 00 ins. forward, 14 ft. 00 ins. aft. The after peak tank, 180 feet
522
NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
from tipping centre, is then filled with 40 tons water. Required the
new draught.
Fig 40.
Mean sinkage ~r j^p D j ~ = = 1 inch
Total trim
total moment
LTM.
180X40 72
1500 “15
= 4*8 ins.
Half trim =2*4 ins.
Forward Aft.
ft.
ins.
ft.
ins.
Original draught
12
00
14
00
Mean sinkage
1
1
12
01
14
01
Half trim
—
2*4
+
2-4
Fmal draught
11
10*6
14
03-4
Half the total trim is allocated to each end.
Example .—Given T.P.I. 53. tons, I.T.M. 1423 foot-tons. Find the
effect of adding 100 tons to No. 1 hold 150 feet forward of the tipping
centre.
Fig. 41
CARGO AI-TD TRIM
523
i'.L r ! , , tOnS 100
Change of mean draught=—— =— =1-89 inches
1 Jr 1. 53
Total trim =
total moment 150 X100
I.T.M.
1423
=10*5 inches
Half the total trim is allocated to each end of the ship so that she
will go down 5J ins. forward and rise 5 J ins. aft and increase her mean
draught 1«89 inches.
A rough approximation of the I T M. may be found when one has a
ship to experiment with by noting very carefully the ship’s draught,
then running up a double bottom tank, and again carefully noting the
new draught. The weight of water in the tank can be got from tne
ship’s displacement scale and the distance of its centre of gravity from
the tippmg centre measured from the profile plan.
Example .—The centre of gravity of No. 6 D.B. tank is 150 feet
abaft the tipping centre and contains 221 tons water.
ft. ins. ft. ins.
Draught before filling 12 06 F 12 06 A
Draught after filling 11 06 13 06
— 1 00 + 1 00
The total alteration of trim is therefore 24 inches.
Total trim =
total moment
I.T.M.
or, 24 ins.=
150 ft. X 221 tons
LfM.
I.TM. = 150x221^24=1381 foot-tons.
. The I.T.M.=1381 foot-tons, a. quantity which would yield, theoreti¬
cally, answers approximately correct for that particular draught.
Example ,—The draught of a ship on arrival at a port of call will be
22 ft. 01 ins. forward, 24 ft. 10 ins. aft, when cargo will be discharged
as follows: T.P.I. 53 tons; I.T.M. 1423 foot-tons, what will her draught
be then ?
524
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
From hold
Tons
Distance
Moment in
from T.C.
foot-tons
No. 1
500
150 F.
75000 Ford.
2
67
88 F.
5896 „
3
125
23 F.
2875 „
4
370
100 A.
37000 Aft
5
150
152 A.
22800 Aft.
1212
83771 Ford.
—
59800 Aft.
The resultant decrease of moment
23971 Ford.
AFT
Forward
Feet
152 lOO
25
68 too
i r~
T ’ C 1
1 1
Tons
v ♦
iso mo
♦
•OS
V |
•7 500
Fig 43.
tons 1212
Mean rise =——- =——==22-9 inches
T.P.l. 53
Total trim = 23971-f- 1423=16*8 indies
Forward
Aft
ft.
ins
ft.
ms.
Original draught
22
01
24
10
Mean decrease
l
10*9
1
10-9
20
02*1
* 22
1M
Half total trim
—
8*4
+
8-4
New draught
19
5*7
23
7*5
Example .—Assuming the ship’s draught as in .previous question
to be 19 ft. 5*7 ins. forward, 23 ft. 7*5 ins. aft, required to find the distance
400 tons will need to be moved to bring the ship on to an even keel;
LT.M. 1423.
ft.
ins.
Draught forward
19
05*7
" aft
23
07*5
Total trim
4
01*8 = 49*8 inches
CARGO AND TRIM
525
If total trim
total moment
I.T.M.
then 49*8 ins.=
moment „
1423
Moment=49*8x1423=70865 *4 foot-tons and—
Distance =moment weight=70865 *4-HW30=177 ft.
The centre of gravity of the 400 tons weight would need to be
shifted forward 177 feet from its present position to bring the ship on
to an even keel, or 800 tons moved forward half the distance, viz., 88$
feet, would bring about the same result.
STABILITY EQUATIONS.
1 .<?<?,_ £ 4 ?
1 W
Where G G x is the shift of G
d the distance through which
w the weight has been moved
W the ship’s displacement.
2. G M = G G x cot 0.
Where G M is the metacentric height
0 the angle of heel.
3
GM =
d X w
W
cot 0.
4. GZ = <?Msin0.
Where GZ is the righting arm.
5. I.T.M.
LGM X W
12 x l
Where I.T.M. is the inch-trim-moment
LGM the longitudinal metacentric height
W the ship’s displacement
l her length between perpendiculars
‘ 30 T 2
6. I.T.M. (approx.) =
Where T = tons per inch immersion
B = breadth of ship
626 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
L 2
7 -' M =12l
Where L is the length of the vessel
d is the draught
BM the longitudinal metacentric height.
8. Total trim =
Trim moment
not
9. T.P.I. =
L x B
12x35
for box-shaped vessels.
10. T.P.I. =
L x B x Coefficient
12x35
for ship-shaped vessels.
11. Transverse BM = j^gfor box-shaped vessels.
. where B is the breadth and d the draught.
B 2
12. BM = gj- is constant for a triangular body apex down
L 2
13. Longitudinal GM = j^pfor box-shaped vessels.
Stability equations are simplified when applied to box-shaped
vessels of rectangular form as indicated by the following worked
examples. A few similar examples for practice are given in the
exercises which follow from number 34 onwards.
On a vessel of displacement 4000 tons and transverse metacentric
height 1*8 feet, a weight of 12 tons is moved 40 feet across the deck,
find the angle of heel.
dX w 40x12
- W ~ 4,000
==•12 feet.
n . GM _ 1*8 log 0-255273
Lot 0= - .12 log 9-079181
Angle of heel 0*=3° 49' Cot 11-176092
CARGO AND TRIM
527
W
Given KM 16 feet, KG 13*8 feet, dis¬
placement 6000 tons, angle of heel 8°, find
the vessel's righting moment.
GZ=GM Sin 6=2-2 ft x Nat Sin 8°
GZ=2-2ft.x;-1391=-306
Righting moment = W X GZ
= 6000 x -306
= 1836 foot-tons
Find the height of the transverse metacentre about the centre of
buoyancy in a box-shaped vessel, 36 feet beam and 18 feet draught.
B 2
BM = ilr
36x36
12x18
=6 feet.
Metacentre is 6 feet above C. of B.
KB=9 feet, BM=6 feet KM =15 feet.
A box-shaped vessel 200 feet long and 30 feet beam, what will
be her tons ‘per inch immersion ?
T.P.I.
LxB
~ 12x35
200x30
12x35
=14-285 tons.
A rectangular-shaped vessel draws 8 feet. If her I.T.M.=480
foot-tons, and 40 tons is shifted 36 feet towards the stem, find the
new draughts.
Total moment = 40 x 36 = 1440 foot-tons. '
Total trim=
Total moment 1440
I.T.M.
480
=3 Inches.
528
NIOHOLLS’S SEAMAN SHIP AND NAUTICAL KNOWLEDGE
F A
Original draught ... 8ft. Oins. 8ft. Oins.
Half-trim. ljins. 1 Jins.
New draught ... 7ft. 10Jin 8ft. ljin.
Given the following ship dimensions, find her coefficient of
fineness.
L, 450ft., B 56ft., d 24ft., displacement, 12,900 tons.
Jv , , . , L x B x d x coeff.
Displacement m tons =-gg-
„ Displ. x 35 12900 X 35 „ .
•'- Coeff - = LxBxi = 450 x 56 x 24 = ‘ 74
A rectangular tank, 60 feet long, 15 feet wide, and 10 feet deep,
floats at a draught of 5 feet. The tank is divided into three equal
compartments, each 20 feet long. If the middle compartment gets
bilged what will be the new draught of the tank ?
SO_20 20*
A D
When a compartment gets flooded and laid open to the
sea, the mean sinkage of the vessel is equal to the volume of the
lost buoyancy divided hy the area of the waterplane remaining
intact. That is to say :—
Mean sinkage in feet V° lume of V^onABCD cubicfeet.
Area of EB .+ area of CF in square feet.
_ 2Q X 15 >< 5 ,
“ 20x15x2 ~ 2 i feet -
The new draught is 5 feet + 2£ feet = 7| feet.
There is no change of trim, as the centre of gravity has not
changed in a fore and aft direction.
CARGO AND TRIM
529
a box-shaped vessel 200 feet x 42 feet x 20 feet floats on an
even keel, drawing 10 feet. A weight of 10 tons is moved from one
end to the other, required her new draughts.
WL is the original waterline, wl is the waterline after the 10
ton weight has been shifted from one end to the other.
Find (1) T.P.I.
Find (2) I.T.M.
LxB
12x35
30T 2
B
200 x 42
12x35
= 20 tons.
30 x 20 2
42
285*7 foot-tons.
Find (3)* Total trim =
Find (4) Draught
J-trim ...
Trim moment 10 tons x 200ft.
I.T.M.
10ft. Oins.
+ 3 ^-
285*7
10ft. Oins.
- H
=7 ins.
New draughts 10ft. 3£ins. 9ft. 8Jins.
Given a vessel of 2000 tons displacement and a KG of 14 feet,
She then loads 2800 tons, KG 16ft., 800 tons, KG 13ft., 300 tons.
KG 2ft., 200 tons, KG 25ft. When loaded her KM is 15*7 feet.
Find her GM.
Tons.
V.C.G.
Moments.
2800
16
44800
800
13
10400'
300
2
600
200
26
5000
2000
14
28000
6100
88800
530 NICHOLLa S SEAMANSHIP AND NAUTICAL KNOWLEDGE
New KG = = 14*56 feet.
oIUu
but KM when loaded= 15*70
therefore her GM = 1*14 feet.
Required (1) the transverse BM, (2) the longitudinal BM of a
box-shaped vessel, length 150ft., breadth 30ft, draught 15 ft.
(1) BM =
. B 2 30x30
12d ~ 12x15
= 5 feet.
(2) BM =
L 2
12d
150x150
12x15
= 125 feet.
QUESTIONS.
1. What is meant by the moment of a force ?
2. What conditions must be fulfilled to maintain equilibrium
when parallel forces are acting on a body ?
3. Explain what is meant by moment=arm x weight.
4. What is the difference between levers of the first, second and
third class ?
5. Describe and illustrate what is meant by a couple.
6. Describe what is meant by a body being in stable, unstable
and neutral equilibrium. Illustrate your answer in the case of a
cone.
7. Explain what is meant by (i) displacement; (ii) coefficient of
fineness of a ship.
8. Define the terms (i) centre of buoyancy ; (ii) centre of gravity ;
(iii) transverse metacentre; (iv) moment of stability as applied to a
ship.
9. Draw figures and describe exactly the conditions required to
produce stable, unstable and neutral equilibrium in a ship.
10. A ship at sea rolls violently, what may this be attributed to ?
11. Explain what is meant by a ship being (i) too stiff; (ii) too
tender ; and what might be done to remedy the conditions ?
QUESTIONS
531
12. Explain tho abbreviations KM , KG and GM.
13. Draw a figure to illustrate a ship having a negative GM.
14. When and by whom is the initial KG determined ?
15. Describe in detail the inclining experiment to ascertain the
GM of a new ship.
16. Define the terms (i) trim ; (ii) tipping centre ; (iii) tons per
inch immersion ; (iv) inch trim moment; (v) total trim.
17. Explain the principle of computing th£ total trim oi a vessel
when a weight is moved forward or aft.
532
NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
EXERCISES.
18 In an inclining experiment 100 tons of ballast was shifted from
starboard to port, its centre of gravity moving through a distance of
30 feet and inclining the ship 8°—ship’s displacement 9000 tons.
Required the G M, Answer. —2-37 ft.
19. The displacement of a ship was 2600 tons when an inclining
experiment was being conducted. A weight of 3 tons was moved 40
feet transversely from gort to starboard and a plumb line 29 ft. 6 ins.
long was deflected 2 inches. Find the G M. Answer. —8-17 ft.
20 A ship is loaded as follows:—
Cargo—Tons 500 750 620 550 400* 300 200
V.C.G.—Feet 12 14 16 18 20 22 23
Initial displacement of ship 1600 tons and KG 12 feet 11 K M in
load condition is 17 feet, find the new G M.
Answer. — G M 18 feet.
21. A vessel’s displacement on arrival in port is 6000 tons, the
V.C.C. being 16 feet. Cargo is to be discharged as follows when K M
will be 13-5 feet. Find what the G M will be after discharging from—
’Tween deck 1500 tons, V.C.G. 21 ft.
Lower holds 2000 „ „ 17 „
„ 1200 „ „ 12 „
Answer. —1*1 feet.
*
22. A tanker has 10,000 tons of oil in her main tanks, the C. of G
being 20 feet above the keel; ten summer tanks each of 200 tons
capacity having their C. of G. 30 feet above the keel. The ship’s light
displacement is 4500 tons and initial C. of G. 18 feet above keel. If
the K M in load condition is 22 feet, find the new G M.
Answer. — G M 1*3 feet.
23. A ship of 5000 tons displacement has a weight of 200 tons
shifted from 10 feet above her C. of G. to 10 feet below it. Find the
new G M the old G M being — 3 inches.
Answer .— G M 6*6 inches.
24. (i) From the following information calculate the ship’s G M.
Displacement 4650 tons in light condition and V.C.G. 22 feet, the
K M after the following loads were put on board being 23-6 feet.
Tons 1500 2500 1700 1950 1700 1000
V.C.G.—Feet 22 24 26 28 18 16
Answer. — G M 10’8 inches.
EXERCISES
533
(ii) The following bunkers were worked off during the passage.
Required the new GM, assuming the K M for the new draught to be
24 feet:—
Tons 300 200 500
V.C a.—Feet 24 26 18
Answer.—G M 1*2 feet.
25. Eocample —From the following information construct a cargo
plan and fill in the column headed “Moments,” also the blank spaces
and compute the ship’s G M when loaded.
Given light displacement 2000 tons, height of centre of gravity
(K G), 12 feet height of metacentre (K M) 17 feet when loaded with
cargo as indicated below.
Compartment
Contents
Weight
Tons
VCG
Feet
Moments
No 1. Lower
Coal
800
11
’Tween deck
General
200
23
No 2. Lower
Rails
300
Paint
100
15
Tubes
300
15
Cement
100
15
’Tween deck
General
> 300
23
No 3. Lower
Cement
500
7
Bales
100
15
Paper
200
15
’Tween deck
General
200
23
No. 4. Lower
Coal
700
11
’Tween deck
General
200
23 !
Side bunkers
400
9
Weight of ship
2000
12
6400
ZG 1 =
moment
— — feet
weight
K G 1 in.
load condition
= feet
EM
»> >»
— feet
G 1 M
= 4-15 feet.
26. (i) The vertical centre of gravity of a ship of 3500 tons
displacement in light condition is 18 feet above the keel. Cargo is
to be received and stowed as follows:—
Weight—Tons 400 1000 1200 1100 900 600 400
V,C.G*—Feet 16 18 20 24 26 28 30
5S4
NJCHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Find the position of the resultant C. of G., and also the G M if the
metacentre is 205 feet above the keel.
Answer. — G M —'4 feet.
(ii) The above GM being unsatisfactory it is decided that two
ballast tanks shall be run up, No. 3 tank 300 tons, V.C.G. 2 ft. and No. 4
tank 400 tons, V.C.G. 1 *5 ft. Find the new G M assuming the K M
to be 20*5 feet.
Answer .— G M 1 foot.
27. Given the following information from a cargo plan. Find the
new C. of G., and if the KM is 22 feet find also the G M .:—
Weightr-Tons' 1000 1500 1250 1100 900 600 400
V.C.G.—Feet 24 22 21 19 23 25 18
Light condition of ship 3250 tons displacement, initial C. of G. 20
feet above keel.
Answer —*8 feet.
28. At the first port of call the following cargo was discha ged from
the above ship, find the new GM assuming KM to be 22 feet:—
Weight—Tons 400 300 500 600
V.C.G.—Feet 20 22 23 24
Answer. —11 foot.
29. A ship arrived in port, draught 21 ft. 00 ins. forward, 23 ft. 00 ins.
aft, and discharged cargo as follows:—If her T.P.I. is 45 tons and her
I.T.M. is 1100 foot-tons, find her new draught.
Cargo in tons 200 450 300 500 200
Distance from T.C. in feet 30F 25 F 50 F 35 A 40 A
Answer. —17 feet 8^ in^. forward.
20 „ 2} „ aft.
30. It is desired to bring a ship on to an even keel, her present
draugnt is 17 ft. 08*2 ins. forward, 20 ft. 01-6 ins. aft. and I.T.M. 1100.
foot-tons. What distance must 300 tons of cargo be shifted forward
to do so?
Answer. —107*8 feet.
EXERCISES
535
31. A ship in light condition has displacement of 2000 tons, centre
of gravity being 17 feet above keel. She loads:—
(a) 5000 tons cargo C of G. 16 feet above keel.
(b) 300 „ „ 10
(c) 100 „ „ 20
Find the height of the centre of gravity of loaded ship.
Answer. —New KG 16*1 feet.
32. A vessel displaces 4000 tons. Initial transverse metacentric height
1-2 feet. A weight of 40 tons deck cargo is shifted to the lower hold a
distance of 20 feet vertically. Find the final metacentric height.
Answer —New G M 1 *4 feet.
33. A vessel in light condition displaces 1800 tons and the C of G. is
10 feet above the keel. She loads 3400 tons of cargo 9 feet above keel,
and 400 tons bunkers 16 feet above keel. The height of the transverse
metacentre in the loaded condition is 12 feet above the keel. Find the
metacentric height.
Answer. —New G M 2 ft. 2*2 ins.
34. A box-shaped vessel 600 feet long is floating at a mean draught of
10 feet forward and aft. If the moment to change trim 1 inch is 240
foot-tons, find the change of trim caused by shiftingg 20 tons aft through
48 feet.
Answer. —9 ft. 10 ins. forward, 10 ft. 2 ins. aft.
35. Ship 2000 tons displacement. A weight of 10 tons is shifted
20 ft, transversely across the deck. Find the shift of the centre of
gravity. If the vessel were upright before shifting the weight and she
heeled 8°, find, the initial transverse metacentric height.
Answer. —6? G f 1 =0-1 ft. (?M=0*7 ft.
36. A box-shaped vessel floating upright, at 7 feet draught is 180 ft.
long, 20 ft. wide, 10 ft. deep, and has no G M. Find the G M when a
weight of 40 tons is shifted from the deck to the bottom of the vessel.
Answer.—GG 1 ^ 0*55 ft. G M= 0-55 ft.
37. Ship 1500 tons is floating at 12 ft. draught. A weight of 25
tons is moved from the lower hold port side to the ’tween deck starboard
side through a distance of 55 ft. Find the shift of G G.
Answer ,— G G x .=; 11 ins.
636 NICHOLL&’s SEAMANSHIP AND NAUTICAL KNOWLEDGE
38. Vessel 210 ft. long is drawing 10 ft. on even lccel in salt water.
A weight of 25 tons is moved horizontally towards the stern 30 ft. Find
the new draughts, assuming the centre of flotation to be amidships
and the I T.M.=250 foot-tons.
Answer —Forward 9 ft. 10J ins. Aft 30 ft. 1| ins.
39. —Ship 300 ft. long, draught 21 ft. forward and 22 ft. aft. The
I.T.M.=480 foot-tons and a weight of 40 tons is moved 50 ft. aft. Find
the new draughts.
Answer .—Forward 20 ft. 9*9 ins. Aft 22 ft. 2*1 ins.
40. Find the total pressure on a keel plate 20 ft. X 3 ft. at 10 ft. draught
on an even keel in salt water.
Answer, —38,400 lbs.
41. A vessel’s light displacement is 3 800 tons K.G.=10 ft. She loads
3400 tons of cargo, K.G.=9 ft., and 400 tons bunkers, K.G. 16 ft. Find
the new K.G.
Answer. —9*82 ft.
42. Ship of 1600 tons displacement has C.B. 8 ft. above keel, K.G.
10 ft and K.M* 11*5 ft. Find the angle of heel if a weight of 8 tons were
moved 20 ft. transversely
Answer .—3° 49'.
43. A box-shaped vessel 200 ft. X 40 ft. X18 ft. floats at a draught of
10 ft. Find K.M.
Answer. —K.M. 18*33 ft.
44. A vessel of 5000 tons displacement with K.G. 15*8 ft. has hex
transverse metacentre 18 ft. above the keel Find her righting moment
when she is heeled 7°.
Answer .—Righting moment of 1340 foot-tons.
45. A ship of 3330 tons displacement draws 17 ft. 0 ins. forward and
16 ft. 6 ins. aft. Her T.P.I. is 21 and her I.T.M. 275 foot-tons. Her
No. 5 tank of capacity 78 tons is run up. Find her new draught if
CG of the ballast is 50 ft. abaft the tipping centre, which is assumed to
be amidships.
Answer. —Forward 16 ft. 8*6 ins. Aft 17 ft. 4*8 ins.
46. Required (1) the transverse B.M.; (2) the longitudinal B.M.;
EXERCISES
637
(3) tons per inch immersion (4) inch trim moment of a rectangular
shaped vessel length 200 ft., breadth 30 ft., draught 10 ft.
Answer. (—1) 7| feet; (2) 666.6 ft.; (3) 14f- tons; (4) 204 foot-tons.
47. A rectangular tank 100 feet long, 10 feet broad, 12 feet deep
draws 4 feet of water. The tank is divided into five equal watertight
compartments, but Nos. 2 and 4 get bilged; find the mean sinkage due
to the loss of buoyancy.
Answer. —2f feet.
A Cargo of Esparto Grass.
CHAPTER XIX.
THE REGISTRATION AND CERTIFICATION OF
SHIPS AND SEAMEN.
The Shipping Industry is subject to the provisions of the
Merchant Shipping Act, which is the longest Act on the Statute
Book. The responsibility for its administration is vested in several
Government Departments.
The Board of Trade is charged with the duty of not only
drawing up rules and regulations for the safeguarding of life and
property at sea but of ensuring that they are adhered to ; such, for
example, as the Load Line Regulations which are now International
in application, the carriage of goods by sea, life-saving appliances
on board ship, navigational apparatus, registration of ships, inquiry
into casualties, shipping and discharging crews and their accommoda¬
tion on board, certification of masters, mates, engineers and
lifeboatmen.
The Customs and Excise is the office through which ships are
registered as having cleared inwards and outwards at British ports.
All goods imported into the country or exported must be recorded
and vouched for at the Custom House and duty thereon paid, or
guaranteed, before they are released for shipment.
The Ministry of Health is responsible for granting pratique to
vessels arriving from overseas, and the visiting medical officer
decides whether the ship is healthy, suspect or infected. The
inspection of the crew accommodation from a sanitary point of
view is carried out by this Department and also the deratisation of
The Home Office is concerned with the administration of the
Factory Act as applied to docks and ships.
The Ministry of Labour, through its exchanges, deals with
questions of employment, unemployment, payment of benefits, etc.
538
REGISTRATION AND CERTIFICATION OF SHIPS AND SEAMEN 539
Ministry of Agriculture and Fisheries attends to the
carriage of live stock in home trade and foreign-going vessels, also
to the interests of the fishing industry generally and the policing of
prohibited fishing areas.
Port and Local Authorities are responsible for the administra¬
tion of the areas within their jurisdiction and of such statutory
powers as have been granted to them by the Legislature, such as
the effective lighting and buoying of harbour approaches, pilotage,
levying dock dues, etc.
Classification Societies are not Government Departments
although they work in co-operation with the Marine Department on
matters affecting the seaworthiness of ships.
There seems to be a somewhat unnecessary distribution of ship
inspectorate duties amongst the several Government Departments,
particularly that of the Board of Trade and the Home Office, and
when, as on the recent occasion of a modern up-to-date cargo vessel
undergoing a routine overhaul, there were seventeen individual
surveyors inspecting various things during the ten days she was in
port it would seem that there is an opportunity here for introducing
a little more concentration of supervisory control.
His Majesty’s Stationery Office.—Passing reference to such
regulations as enter directly into the business of the seaman have
been made throughout this book, but only briefly, and in part, as
the precise detail of the many regulations and their modified
application to meet uncommon conditions occupies many pages of
numerous publications. The Board of Trade issues periodically a
“ List of the Principal Acts of Parliament, Regulations, Orders,
Instructions, Notices, etc., relating to Merchant Shipping/’ with
a special list of any Supplementary Circulars that may have been
issued since the previous List was published. The List may be
obtained from His Majesty’s Stationery Office, Adastral House,
Kingsway, London, W.C.2, price 6d.
The existence of these publications is not known generally to
seagoing men as they are grouped according to the- following
interests :—Shipowners ; Fishing Boat Owners ; Boiler Makers and
Users; Boat Builders; Shippers of Cargo ; Manufacturers of
Anchors and Chain Cables, Fire Extinguishers, Fog Homs and
540 NICHOLLS’S gEAMANSHIP AND NAUTICAL KNOWLEDGE
Steam Whistles, Nautical Instruments and Ships’ Navigation
Lanterns.
We give here a list of the more important of these publications
but not of the numerous supplements issued separately as
circumstances may dictate.
1. Anchors and Chain Cables Act. 1/-
2. Coal Cargoes, various circulars.
3. Dangerous Goods. 2/-
4. Deck Cargoes. Deport on Timber. 2/-
5. Emigrant Ships. 1/-
6. Eire Precautions, various circulars.
7. Grain Cargoes. 6d.
8. Instructions as to Survey of Life-saving Appliances. 2/6
9. Load Line Pules. 1/9
10. International Convention respecting Load Lines. 3/-
11. National Health and Pensions Insurance.
12. Instructions as to the Survey of Passenger Steamships. 1/6
13. Safety of Life at Sea, International Convention. 4/-
14. Tonnage Measurements. 9d.
15. Instructions as to the Survey of Master’s and Crew
Spaces. 6d.
16. Examination Regulations; Masters and Mates in the
Mercantile Marine. 1/6
“Carriage of Dangerous Goods and Explosives in Ships,”
1935. H.M.S.0.2/-.—This is a Report of a Departmental Committee
appointed to consider the existing Board of Trade Memorandum on
the Carriage of Dangerous Goods. The Board has decided to
adopt in substitution of the present Memorandum that part of the
Report which contains particulars of packing, labelling and stowing
applicable to various substances.
The substances have been classified into seven categories, viz.
1. Explosives. 2. Compressed “permanent,” liquefied and dis¬
solved gases. 3. Substances which become dangerous by interaction
with water or air. 4. Substances giving ofi inflammable vapours.
6. Poisonous substances. 7. Miscellaneous.
A section is devoted to each category in which is grouped in
alphabetical order the names of dangerous goods with instructions*
to manufacturers, packers and stevedores regarding the packing,
PLANS
541
marking and stowage thereof, with notes for the information of
officers as to the dangerous properties of the various substances.
The danger may arise from liquefied gases that are poisonous
or inflammable, such as chlorine, hydrocyanic acid, etc.; or gases
carried in cylinders under pressure which may expand with heat
and burst the containers. Leakage of vapour which may form
explosive or inflammable mixtures with air, or substances that
become dangerous on contact with water, calcium preparations
for example, petroleum spirits, etc.
In general, all such goods should be stowed away from foodstuffs
and living quarters, in cool, well ventilated spaces, and if on deck
they should be protected from the rays of the sun. The quantity
of deck goods should not exceed 50 per cent, of the total deck
area. Cylinders containing gases under pressure should be stowed
not less than 8 feet from the ship’s side under cover. Dangerous
goods to be distinctively labelled and the nature of the danger,
whether inflammable, corrosive or poisonous to bo clearly stated
on the package.
PLANS.
The upper drawing is a profile or sheer plan of a vessel showing
the position of three waterplanes.
The waterplanes are projected on to the half breadth plan,
which exhibits as curves the shape of each waterplane area as if
ttie vessel were sliced into horizontal sections at the level of each
respective waterplane.
The vertical lines numbered 1, 2, 3, etc., are frame stations.
542 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
and these are drawn on the body plan, as they would he seen if
the ship were viewed end on from forward and from aft. The
frames are bent to their curvature as shown on the body plan.
The fore and aft line on the half breadth is called a bow and
buttock line, and it is represented on the body plan by the two
vertical lines on the fore and after body’s. If the ship were sliced
vertically-for the whole of her length along that line her side would
be laid open and the shape of the opening would be the same as the
curved line running fore and aft on the sheer plan.
By reconciling or fairing up ” the respective lines and curves
on the three plans the naval architect designs the shape the vessel
will eventually be when built.
THE NEW SHIP.
The preliminary arrangements to finance the ship having been
satisfactorily completed a ship is ordered. The contract price
usually stipulates that the builder shall receive one-fifth when the
keel is laid, one-fifth when framed, one-fifth when plated, one-fifth
when launched and the final fifth of the purchase price when the
completed ship is handed over to the owners.
UNDER Ketu Buock^
Fig- 1.—The Keel Blocks are removed before the vessel is Launched.
Plans of the proposed vessel are submitted by the builder to the
Classification Society’ under whose rules she is to be built, either
Lloyd’s or British Corporation. During the period of her construction
the ship is frequently inspected by the surveyors of the Society.
Reference is made on pages 482 and 483 as to how the scantlings of
various parts of the structure is regulated by numerals. The
LAUNCHING THE SHU-
543
Equipment Numeral, which is perhaps of more interest to the deck
executive than the others, is determined by the Second Numeral,
Lx (B + D), with some modification for superstructures; for
example, a ship of the dimensions of the Caledonian Monarch, a
vessel of 9,400 deadweight, has an Equipment Numeral 37195, and
we find, on referring to Lloyd’s Tables, that such a vessel must
have three bower anchors weighing 63f ewts. each, tested to
50| tons.
Stud chain cable, 270 fathoms, minimum size 2J inches, proved
to a load of 91 tons, breaking test 127^ tons, minimum weight
682 cwts.
One stream anchor, weighing 17£ cwt., tested to 18| tons
and 90 fathoms of lj-inch stream chain, or, as an equivalent to chain,
90 fathoms of 4f-inch steel wire of breaking test, 47 tons.
A towline, ,120 fathoms of 14-inch hemp, or, as an equivalent,
120 fathoms of 5-inch wire.
Two hawsers, 90 fathoms each of 8 inch hemp, or 2f-inch
wire.
Two warps of 7-inch hemp, or 2|-inch wire.
A vessel of approximately 5,000 tons deadweight having an
equipment number 24200 is provided with bower anchors weighing
45 cwt. each and a 12-cwt. stream anchor with a 4£-inch steel wire.
The size and number of shrouds is regulated by the length of the
mast measured from the upper deck to the hounds. A mast, 50 feet
long, must be fitted on each side with three shrouds of at least
3f-inch wire, one topmast backstay of 3-inch wire and one forestay
of 3|-inch wire.
LAUNCHING THE SHIP.
The weight of the vessel during construction is borne on the
keel blocks and on bilge shores, but when being launched she slides
down on launching ways. These are rectangular timbers laid the
whole length of the ship, parallel to each other, to form a trackway
extending beyond the slipway into the water. They measure
about 4 feet wide and 18 inches thick, placed on each side of the
keel about one-third of the vessel’s breadth apart with a declivity
of about eleven-sixteenth inch to the foot.
REGISTRATION AND CERTIFICATION OF SHIPS
545
The ways are in two parts ; the standing ways have their
foundation on the ground and have vertical lengths of wood bolted
along their outer edge to prevent the sliding ways, which rest on
top of the standing ones, from slipping outwards.
A framework of wood and iron is built under the vessel and
wedged up tight under her bottom to form'a cradle for her to rest
on. The sliding part of the ways, that is the top logs, forms the
bed of the cradle which supports the weight of the ship for about
80 per cent, of her length. The ends of the cradle are carried higher
up the ship’s side than the intermediate part, the end part of the
structure being called the forward and after poppets. When ready
for launching the building blocks are knocked clear of the ship,
the cradle takes the weight of the vessel, then, when the last
supporting block is removed, the moving log, cradle and ship all
slide together down the well greased ways. The vessel is then
taken to the fitting out berth.
REGISTRATION AND CERTIFICATION OF SHIPS.
Carving Note.—Before the ship is handed over by the builders
the owner gets from the Custom House a form called a “ carving
note ” which he fills in, stating the proposed name of the vessel,
her port of registry, tonnage, etc., and requests that she may be
registered. This note takes its name from the fact that the ship’s
tonnage and official number are carved or cut out on her main beam
or hatch coaming.
The Certificate of Registry is then granted by the Custom
House. It is, as it were, her birth certificate. It gives particulars
of the ship, when and where built, her type, name, port of registry,
official number, signal letters, horse power of engines, principal
dimensions, cubic capacity and other points of identification, also
the owner’s name.
The master’s name is endorsed on the register. This must be
done as soon as he takes command by the Chief Officer of Customs
at the Custom House, or by the British Consul at a foreign port.
Changes of ownership must be endorsed on the certificate, and if
the ship be lost, or passes under a foreign flag, the certificate is to
be returned to the Board of Trade.
546 NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
The certificate of registry is inspected by Custom House officers
at home and abroad every time the ship is entered inwards or
outwards at a port. The Shipping Office routine with regard to
depositing the Register, the crew's articles of agreement and
recordmg changes m the crew as carried out at a homo port in the
Mercantile Marine Office is transacted abroad by the British Consul.
Anchors and Chain Cables Act.—A certificate is granted by
a Lloyd’s Proving House licensed by the Board of Trade for the
testing of anchors and chain cables according to this Act. Refer
back to pages 122 and 123.
The Freeboard and Load Line Certificate is granted by
the Board of Trade, or by one of the three assigning authorities,
and subsequently ratified by the Board of Trade. Refer also to
pages 376 to 378.
Life-Saving Appliances Safety Certificate.—The* Marino
Department of the Board of Trade is charged with the responsibility
of ensuring that the Rules and Regulations relating to the Safety
of Life and Property at Sea are complied with. The surveyors
are departmentalised as Engineer, Shipwright and Nautical
Surveyors ; the engineers attend to the engines and boilers; the
wrights to the hull and structure ; the nauticals to the navigational
and life-saving appliances. The duties of each may occasionally
overlap.
Cargo Vessels are granted a L.S.A. Certificate by the Board
of Trade after inspection of life-saving appliances, lights, sound
signals, etc. The Surveyors are at liberty to board British ships
at any port in the U.K. to m ak e this inspection or they may be
called in for the purpose. The period of validity of this certificate
is not specified, but they are renewed from time to time,
*
Passenger Vessels.—When a passenger vessel is to be surveyed,
the hull is examined in dry dock and cables ranged, shackle pins
removed and replaced, and her certificate of cables and anchors
verified. All holds and bilges are thoroughly cleaned and examined#
Boats, davits and equipment, life-saving appliances, lights, signals,
compasses, lifebelts and lifebuoys, fire-extinguishing apparatus, etc.,
all inspected and passed; boats lowered into the water and
REGISTRATION AND CERTIFICATION OF SHIPS
547
examined for leakage ; medical stores, hospitals, dispensary are
also inspected by the Board of Trade.
Crew’s accommodation examined for space, fittings, ventilation,
ladder ways, lavatory conveniences, and the certificates of the
master, officers and engineers inspected. All watertight doors, deck
equipment and gear are subject to inspection, and in fact everything
that the Surveyor may consider tends to make any part of the ship
and conveniences efficient. Compasses must be adjusted occasionally,
and a certificate is required of the master that any errors are known
to him.
Safety Radiotelegraphy Certificate.—Under the Merchant
Shipping Safety and Load Line Convention, 1932, the wireless
apparatus of both passenger and cargo vessels is subject to an
annual survey by the Board of Trade. In the case of cargo vessels
a Safety Radiotelegraphy Certificate is issued, but in passenger
ships this certificate is embraced by the Passenger and Safety
Certificate.
International Load Line Certificate.—Under the above
Convention, the freeboard is required to be verified annually. This
is carried out by the Classification Surveyor, and the International
Load Line Certificate is endorsed accordingly in the space provided.
The certificate is renewed every four years when the class survey
is carried out.
Survey of Master’s and Grew Spaces.—A deduction is
allowed from the tonnage measurement of the vessel in respect of
space solely appropriated for the use of seamen and apprentices,
the deductible space consisting of sleeping rooms, messrooms,
bathrooms, washing places, oilskin and overall lockers, pantries,
food lockers, drying room, hospital.
There must be for each man a space not less than 120 cubic
feet and 15 superficial feet, the space to be at least 6 feet high, and
the flooring to be of wood or an approved composition laid on a
steel deck.
The living quarters must be efficiently lighted, the minimum
standard to be the provision of sufficient natural light when the
ship is new and paint clean, that it will be possible in clear weather
to read the print of an ordinary newspaper in any part of the space.
548 NIOHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
If this standard is impracticable electric lighting may be accepted
under approved conditions. Satisfactory ventilation must be
provided and the spaces protected from effluvium which may be
caused by cargo or bilge water. Provision should be made to
ensure daily a sufficient supply of fresh water for washing purposes.
Grew Spaces must be Clean and Clear.—In addition to a
daily cleaning out, crew spaces should be thoroughly cleaned, the
partitions, sides and bunks being washed three or four times a year,
and the space should be painted, preferably white or a light coloV
as a rule, every two years. All crew spaces must be kept in a fit
condition for the proper accommodation of the men who occupW
them, and if in a dirty condition, and this condition is not remedied
forthwith, the space may be disallowed as tonnage. WheneveM a
ship is being registered or re-registered a certificate to the effect tbiat
the crew space has been inspected must be sent by the Surveyor
to the Registrar of Shipping at the port of registry. j
Certificated Lifeboatmen.—Passenger ships are those carryin*
more than 12 passengers on international voyages or home trad®.
Emigrant ships are those carrying from the British Isles to a«|
port out of Europe or the Mediterranean more than 50 steeragBp
passengers, or a greater number than one passenger for ever®
20 tons of the registered tonnage. ^
The crews of such ships shall include for each boat at least two ’
certificated lifeboatmen when the prescribed complement of the
boat is less than 41 persons; three lifeboatmen when the boat's
complement is from 41 to 61 persons; four lifeboatmen from 62
to 85 persons, and when the complement is over 85 persons five
lifeboatmen per boat.
An applicant for a lifeboatmen’s certificate must be at least
18 years of age, has had sufficient service at sea, and has been
trained in all the operations connected with launching lifeboats and
the use of oars, and that he is acquainted with the practical handling
of the boats themselves. The applicant has to submit himself for
examination at such times and places as may be directed by the
Board of Trade, and, if found satisfactory, the Board issues a
certificate. The Board of Trade hold the examination on board a
ship, but only at the request of the owner, provided there be a
sufficient number of candidates to form a boat's crew. No official
PANAMA AND SUEZ CANAL CERTIFICATES
549
provision on a national basis for the effective training of ship’s
crews in boat work has, so far (1936), been established in the
United Kingdom.
PANAMA AND SUEZ CANAL CERTIFICATES.
Under Deck Tonnage is a measure of the internal space
between the top of the ceiling or double bottom in the hold and
pig 4 —Steamship in Canal Lock.
the under surface of the tonnage deck. The unit of measurement
is a ton of 100 cubic feet.
Gross Register Tonnage is a measure of the total internal
volume of the ship, and is equal to the under deck tonnage plus the
tonnage of all enclosed spaces above the tonnage deck.
550 NICHOLLS’S SEAMANSIIIP AND NAUTICAL KNOWLEDGE
Net Register Tonnage is the residual tonnage after various
allowances for propelling power, crew spaces and navigation spaces
have been deducted from the gross tonnage.
Canal dues are payable on the tonnage stated in the certificates
granted by the Panama and Suez Canal Authorities respectively.
The assessable tonnage space is based on the Panama and Suez
rules which, in some respects, differ from each other and from
the British rules, so that all vessels using these Canals must be
inspected and measured for these certificates. The Panama Canal
net tonnage is based on the ship’s actual earning or cargo carrying
capacity, and includes all covered in spaces such as forecastle,
poop, bridge space, shelter deck or ’tween decks, and this tonnage
determines the canal dues to be paid by the ship. The tolls are
$1.25 per ton for loaded vessels and $0 75 per ton when in ballast
with, in the latter case, a restriction as to the quantity of bunkers
that may be allowed in lieu of ballast. The Suez Canal toll is 5/9 per
ton for loaded ships and half that amount for vessels in ballast, with a
levy for passengers: 5/9 for each adult and 2/10J for each child
between 3 and 12 years of age. Additional charges are made by
both Canal Authorities for pilotage, towage, etc.
MINISTRY OF HEALTH.
Port Local Authority.—When a vessel enters a port from
overseas she is visited by the boarding Medical Officer of Health,
to whom the master gives in the following form a “ Declaration of
Health.” If the ship is healthy the medical officer certifies that he
has examined the ship and finds no medical reasons for withholding
pratique.
The Immigration Officer ascertains, with regard to aliens
entering the country, the length of their stay, the purpose of their
visit and the amount of money in their possession. No alien is
allowed to land who is a lunatic or mentally defective, or suffering
from T.B., leprosy, etc., or in a verminous condition.
DECLARATION OF HEALTH
(To be rendered by the Master of a foreign-going ship arriving in Great Britain
or Northern Ireland from a foreign port)
The attention or the Master is directed to the Instructions
under Articles 5, 6 and 19.
Name of Vessel ............
From ... Via .....
Nationality .... Net Registered Tonnage .
DECLARATION OF HEALTH
651
HEALTH QUESTIONS
1. Has there been on board during the voyage * any case or
suspected case of Plague, Cholera, Yellow fever. Typhus
fever, or Smallpox ? (Give particulars in the Schedule) .
2. Has plague occurred or been suspected amongst the rats or
mice on board during the voyage ? *
3. Are you aware of sickness or deaths amongst the rats or mice
on board other than is attributable to poison or any other
method employed for killing them ...
4. Has any person died on board during the voyage * otherwise
than as the result of accident ? (Give particulars m the
Schedule) ...*, . .
5. Is there on board or has there been during the voyage * any
case of illness which you suspect to be of an infectious
nature ? (Give particulars in the Schedule)
Note.— In the absence of a surgeon, the Master should
regard the following symptoms as grounds for suspecting the
eolstence of infectious disease :—Fever accompanied by
prostration or persisting for several days, or attended with
glandular swellings; or any acute skin rash or eruption,
with or without fever ; severe diarrhoea or diarrhoea with
symptons of collapse; jaundice accompanied with fever.
6 . Are you aware of any other condition on board which may
lead to infection or to tlio spread of infectious disease ? .
* I hereby declare that the particulars and answers to the questions given in
this Declaration of Health (including the Schedule) are true and correct to the
best of my knowledge and belief.
Date . (Signed) .
( Master)
(Countersigned) .
(Ship*s Surgeon)
*If more than six weeks have elapsed since the date on which the voyage
began, it will suffice to give particulars for the last six weeks.
DUTIES OF MASTER.
Health Conditions on Board.
Article 5.—The Master of a foreign-going ship approaching a district
from a foreign port must ascertain the state of health of all persons on board,
and in terms of Article 13 shall fill in and sign the Declaration of Health.
Article 6 (Wireless Messages). —If the answer to any of the questions
I to 6 is “ Yes,” free pratique will not be granted by His Majesty’s Customs
552 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
until the vessel has been visited by the Port Medical Officer. The Master
should therefore:—
(1) Send a wireless message to the Port Local Authority stating the
name of his vessel and the time when the ship is expected to arrive. This
message must be sent off not more than twelve hours and not less than
four hours before the arrival of the ship.
(2) If the ship is not fitted with wireless, notify the Port Sanitary
Authority of the arrival of the ship as soon as possible.
Article 9 and Third Schedule (Use of Flags and Signals). —The
Master should hoist whichever of the Quarantine Signals is appropriate, as set
out in page 356 of the British Edition of the 1931 International Code of Signals
for Visual Signalling, in accordance with Part II. of the Third Schedule, as
follows:—
“ (a) By Day , during the whole time between sunrise and sunset, when the
ship is within three miles of the coast or is within the limits of
the district—
(i.) the Flag Signal Q, meaning—‘ My ship is healthy, and
I request free pratique ’;
(ii.) the Two-Flag Signal QQ, meaning—* My ship is
suspect, that is to say, I have had a case or cases of
infectious disease more than five days ago, or there is
an unusual mortality among rats on board 5 ; or
* (in.) the Two-Flag Signal QL, meaning—* My ship is
infected, that is to say, I have had a case or cases of
infectious disease less than five days ago.’
The day signal shall bo shown at the masthead, or where it can
best be seen.
“ ( 6 ) By Night , during the whole of time between sunset and sunrise,
but only when the ship is within the limits of the district, a
signal comprising a red light over a white light, the lights being
not more than six feet apart and meaning * I have not free
* pratique.’
The night signal shall be shown at the peak or other conspicuous
place where it can best be seen.”
Article 19 (Deratisation and Deratisation Exemption Certificates .
Under Article 19, when a ship arrives from a foreign port, the ship’s Deratisation
Certificate or Deratisation Exemption Certificate must be produced for
inspection by the Officer of the Port Local Authority.
This Declaration of Health must be completed and ready to deliver to the
Officer of 'H.M. Customs, or Officer of Port Sanitary Authority, whichever
shall first board the vessel.
THE MAXIMUM PENALTY FOR BREACH OF THE PORT
SANITARY REGULATIONS IS ONE HUNDRED POUNDS.
DERATISATION
553
FOR USE OF PORT LOCAL AUTHORITY.
Certificate.
Port of Issue.
Date.
Fumigant Used
Deratisation
Deratisation Exemption
DEKATISATION.
Deratisation Certificate.— The International Sanitary
Convention of 1926 made it necessary for all ships to obtain from
the Port Sanitary Authority a “ Certificate of Deratisation,” but
if a ship can be shown to the satisfaction of the Port Authority to
be reasonably free from rats a “ Certificate of Exemption from
Deratisation ” will be granted. Both certificates hold good for six
months.
The onus of keeping the ship free from rats is thrown upon the
ship. If the ship is kept free the Certificate of Exemption will be
issued, if not, then fumigation will have to be undertaken. The
certificate, when issued, must be kept on board the vessel with the
ship’s papers in order that it may be produced at every port. Unless
this is done the ship will have to be inspected again with the
possibility of fumigation having to be carried out. The certificate
will be accepted by every country signing the Convention as
evidence of the ship^being free of rats.
Rats begin to breed from the age of two to three months, period
of gestation three weeks, litter eight to ten rats, very prolific. It
is estimated that the progeny of a pair of rats may reach the colossal
total of 860 in the course of a twelvemonth. There are two species,
the brown rat and the black rat. The brown species is a shore
dweller and burrows; the black rat is a climber, frequents ships and
is a plague carrier, the disease being transmitted to human beings
by fleas.
RATS AND MICE (DESTRUCTION) ACT, 1919.
The attention of Ship’s Master is drawn to the following provisions of the
Act and requirements of the Local Authority:—
PROVISIONS OF THE ACT.
(1) The Rats and Mice (Destruction) Act applies to a vessel as if the vessel
were land, and the Master of the vessel the occupier thereof. Section 6 (1).
(2) The Local Authority may by notice served on the Master of a vessel
554 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
within its district require him to take such necessary and reasonably practicable
steps as are prescribed by the notice, for preventing the escape of rats ami
mice from the ship, and if the Master fails to comply with the requirements
of any such notice he shall be liable, on summary conviction, to a fine not
exceeding Twenty Pounds.
REQUIREMENTS OF LOCAL AUTHORITY.
(A) To prevent the passage of rats from the vessel to the wharf, the
following precautions must be taken:—
(1) Rat guards should be affixed to mooring ropes in such manner that the
passage of rats from the ship to the wharf is prevented; or
(2) The moorings should be wrapped in canvas and tarred for about two
feet as they leave the ship and reach the wharf.
(3) Cargo gangways should be withdrawn, or tarred or whitewashed, whilst
the ship is “ silent.” Passenger gangways should be well lighted at
night, or removed.
(4) Ship stores and gear should periodically be moved to prevent harbour¬
ing rats, and no refuse food-stufis allowed to accumulate whilst in
port.
(B) To rid a vessel of rats:—
(1) Ships trading with Mediterranean ports east of Marseilles or with other
ports east of the Suez Canal should be deratised at the termination
of each voyage, and whilst the holds are empty. Similar precautions
should be observed on ships trading with South American ports,
and with such other ports as are from time to time reported as
infected with plague.
(2) The most effective method for destroying rats on board ship is by
fumigating the holds, alleyways, cabins, food stores, pantries, living
quarters, chain-lockers, and peaks with sulphur gas, and the Master
or Owner of any vessel which is found to be definitely infested will
be required to use this method.
(3) Simultaneously with this a deck search should be instituted of boats,
steam-pipe casings, winch barrels, or other places which may afford
shelter to rats.
(4) Systematic trapping should be earned out both whilst the vessel is in
port and at sea. If the ship is empty, regular inspection should be
made of holds, store rooms, and elsewhere, and rat hunts instituted.
( 5 ) The keeping of cats on board is of definite advantage.
(6) It is of considerable value when rats are confined within the limits of a
ship to catch them alive, to kill all the females, and to set the males
at liberty on board.
(G) Precautions in handling rats:—
(1) Rats caught alive should be drowned and then burned in the ship’s
furnace. At no time should rats be handled directly owing to the risk
FUMIGATION
555
of accidental plague infection. No rats, dead or alive, must b© taken
outside the dock gates except by consent of the Port Local Authority.
(2) Effort should be directed to keeping the ship rat-free. Any increase in
the number of rats on board or unusual mortality among them
should be reported to the Port Medical Officer immediately the ship
arrives in port.
N.B.—Nothing m this Act affects the power of the Port Local Authority to
deal with rats as a preventive measure against plague. Under the Plague
Regulations, any obstruction offered to an Officer of the Authority involves a
penalty not exceeding One Hundred Pounds, with an additional Fifty
Pounds for each day the obstruction continues.
Fumigation.—In all cases fumigation should, where possible,
be carried out between the completion of discharge and commence¬
ment of loading, in order to prevent any possible damage to cargo,
such as galvanised iron, tin plates, etc., by sulphur, and to moist
cargo, such as salt, by hydrocyanic acid.
Preparation.—The vessel may be fumigated by sulphur fumes
or hydrocyanic acid gas ; the latter is rather dangerous, and special
precautions have to be taken after fumigation to ensure that the
vessel is gas-free before persons, other than the sanitary officials,
are allowed on board.
Limber boards should be removed in the holds and pipe casings
and bilges opened up. ’Tween deck hatches removed, weather
deck hatches to have alternate boards removed and covered with
two thicknesses of tarpaulin. Doors to be opened if leading to the
space being fumigated. Dunnage removed or stacked on an elevated
platform to avoid harbourage for rats. Windsails to be suspended
in readiness for ventilation when fumigation is completed.
Doors of all accommodation should be kept open to allow free
flow of gas; ports to be workable. Keys to be at the disposal of
the fumigating staff before the ship is placed under gas. Cupboards,
lockers, drawers, bins, fuse boxes, etc., to be open, and all beds
lifted. Vents to be closed at deck outlet. Galley fires to be
extinguished.
Immediately before fumigation an officer of the ship is required
to sign a form certifying that all ship’s crew and contractors’ men
are off the ship. After fumigation has commenced, no persons are
allowed on the ship except the fumigation staff or officials of the
556 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Port Sanitary Authority unless at the discretion of the medical
officer or chemist in charge of the fumigation
The time required to clear the ship of gas varies from two to
four hours depending upon the weather conditions, the clearance
being expedited if there is a good breeze to create an active
circulation of air throughout the ship. When a clearance certificate
has been procured from the chemist of the fumigation contractor
it will be safe for persons to go on board. Caution should be observed
in opening any compartments adjacent to those fumigated that
have remained locked for any reason, and a good airing should be
given before such compartments are considered habitable
“The Principle of Hygiene” on board ship is the same
as on land, and is just the observance and practice of health laws
in the prevention of disease. These laws may be summed up in
the one word “ Cleanliness.” Cleanliness in person, clothing,
accommodation and surroundings ; good ventilation in sleeping
quarters, good sanitary and drainage arrangements, good food and
temperate living.
A carbolic disinfectant should be used when washing out crews*
quarters and cleaning up bilges, privies, etc. Bedding and clothing
should be brought on deck for airing and ventilation when
opportunity offers. Caro should be taken with regard to under¬
clothing when passing quickly from one climate to another,
especially in damp and warm weather, so as to protect the body
from sudden changes of temperature. It is asking for trouble to
lie out on deck on a close sultry evening wearing thin cotton
underwear and little else on, then to fall asleep and wake up chilled
during the early hours of a dewy morning. Woollen underclothing
is best. Eating tainted food or too much fruit in tropical countries
is a frequent cause of gastric troubles and feverish disorders.
If infectious disease breaks out on board, such as measles,
diphtheria, fevers, etc., the patient should be isolated from the
rest of the crew and the ventilating, disinfecting and cleansing of
all living accommodation more stringently exercised, and fumigated
if need be to prevent the outbreak spreading.
The patient’s clothing and bedding should be disinfected in
boiling water with a little carbolic acid in it, and, after a few hours’
soaking, they should be exposed to the sun to dry.
TRANSPORT OP LIVE STOCK
657
National Health Insurance applies to all persons over 16 years
of age whose remuneration does not exceed £250 per annum When
estimating the income of an officer there is added to his wages the
value of the board and lodgings provided at the rate of 4/- per
day when serving in cargo vessels and 5/- per day when in passenger
vessels.
Insurable persons join an approved society; the Seamen’s
National Insurance Society is constituted to meet the special
requirements of seafarers. The weekly contribution for members
serving in foreign-going ships is 8d. for men and 7d. for women,
and every four contributions paid on behalf of a contributor in any
calendar year counts as five contributions.
The benefits include medical, sanatorium, dental, sickness and
disablement treatment. Participation in some of the benefits
depends on the number of contributions, and a proportionate loss
of benefit is incurred if the member gets into arrears with his
contributions
THE ANIMALS (SEA TRANSPORT) ORDER OF 1930.
(Pamphlet No. 923).
The Ministry of Agriculture a ^d Fisheries is empowered under
the Disease of Animals Act to issue Regulations relating to vessels
and animals carried thereon ; animals being defined as cattle,
sheep, goats, all other ruminating animals, and swine.
Restrictions.—Animals shall not be carried on more than
three decks, nor on an open main (freeboard) deck, nor on any
deck that is not completely closed and covered with a permanent
deck above ; neither shall they be carried in tiers above a compart¬
ment where other animals are carried, nor in any part of the vessel
where they would interfere with the proper management or
ventilation of the vessel.
Space.—Sufficient space shall be provided in every pen to
enable the animals therein properly to feed and rest during the
voyage, the minimum space per head being 2 feet 6 inches in width
for fat cattle and 2 feet in width for store cattle under 1,000 lbs.
weight. No pen shall exceed 11 feet in length (fore and aft) and
9 feet in breadth, and its construction shall be of such character
and strength as to be able to withstand the action of the weather
558 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
and the weight of the animals thrown against it The floors of
pens and gangways to be fitted with battens or other proper
Footholds.
There shall be a continuous fore and aft gangway at least 3 feet
wide between every two rows of animals and an athwartship
passageway at least 18 inches wide communicating with the fore
and aft passageway in each compartment.
The compartments shall be efficiently ventilated by electric
fans or otherwise of sufficient capacity entirely to change the air
once every three minutes, and the compartments to be adequately
lighted.
All cattle to be securely tied by the head or neck in such manner
as not to cause unnecessary suffering and so as to stand athwartships
facing the passageways.
Gangway doors not less than 5 feet 6 inches in height and
3 feet 9 inches in width shall be fitted in the ship’s side above the
main deck, so placed that the animals can be driven direct across the
deck clear of hatchways or other obstruction.
Every consignment to be under the charge of a responsible
foreman with competent assistants, numbering, with himself, three
attendants for every 100 head of cattle. Proper accommodation
for all these persons shall be provided.
The master of every ship carrying cattlemen from overseas to
a port in the United Kingdom shall furnish to the Immigration
Officer immediately on arrival particulars with regard to any
cattlemen carried, their name, nationality and proposed address.
Every vessel shall carry an approved killing instrument to
slaughter seriously injured animals. A record of casualties shall
be kept stating how many animals died or were killed or injured on
the voyage and the cause of such death.
The Schedules to the Order specify in detail the dimensions
to be observed in the construction of pens and fittings for the
protection of animals. Cattle pens, for example, are 8 ft. x 2£ ft.
X 7 ft. (140 cubic feet), but four are usually carried in a 10-ft.
stall in regular cattle boats.
** Specification for Pitting Ships for the Conveyance of
Horses or Mules” is issued by the Sea Transport Department,
Board of Trade.
659
employees’ liability
THE FACTORY AND WORKSHOPS ACT.
The requirements of this Act are supervised by surveyors
appointed by the Home Office. The part of the Act applying to
ships comes under Dock Regulations, copies of which are exhibited
within the precincts of harbours and on board ships. Penalties are
imposed on employers, employees and other persons who contravene
or fail to comply with the Regulations. Nautical officers should
be conversant with the requirements, and we here refer to some of
the more important that are likely to come within their province.
The United Kingdom Steamship Assurance Association in a
report under the heading “ Loss of Life and Personal Injury/ 9
remarked that “ the most frequent causes of accidents on board
ship are defective hatch covers resulting in men falling into ships
hold and defective gear. If only ships 9 officers would guard against
these two things probably 25 to 50 per cent, of the deplorable
accidents could be prevented.”
Gangways.—When a ship is loading or discharging cargo or
bunkers at a wharf, a gangway shall be provided for the safe means
of access of authorised persons, and when alongside other vessels
or barges the ship with the higher freeboard shall provide the
gangway.
The gangway has to be at least 22 inches wide, properly secured
and fenced throughout on each side to a clear height of 2f feet by
means of upper and lower rails, taut ropes or chains, or by other
equally safe means.
Access to holds, unless permanent footholds are fitted according
to prescribed regulations, shall be by means of ladders, and these
are only to be deemed safe when the cargo is stowed far enough
from the ladder to have at each of its rungs sufficient room for a
man’s feet. All parts of the ship to which persons employed may be
required to proceed in the course of the employment shall be
sufficiently lighted, subject to the safety of the ship, her cargo,
navigation, or to bye-laws or regulations of Harbour Authority.
Hatches.—Portable hatch beams to have suitable gear for
lifting them. Hatch beams and covering to be plainly marked for
the position they belong, and adequate hand grips to be fitted on all
hatch coverings. A hatch is defined as an opening in the deck used
C6U NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Fig. 4 shows the “ T ” and “ B ” Patent Shding Hatch Beam.
Time is saved and accidents avoided when this beam is fitted, as it need
not be unshipped but simply pushed by hand forward or aft to any desired
position as indicated in the illustration.
for the purpose of handling cargo, for trimming, or for ventilation,
and the coamings are less than 2 feet 6 inches in height; such
hatches shall either be fenced to a height of 3 feet or be securely
^overed. Hatch coverings shall not be used in the construction of
deck or cargo stages, or for any other purpose which may expose
them to damage.
No person shall, unless duly authorised or in case of necessity,
remove or interfere with any fencing, gangway, gear, ladder, hatch
SAFEGUARDS
561
covering, life-saving means or appliances, lights, marks, stages or
other things whatsoever required by these Regulations to be
provided. If removed, such things shall be restored at the end
of the period during which their removal was neecssary by the
persons last engaged in the work that necessitated such removal
The fencing required by the Regulations shall not be removed
except to the extent and for the period reasonably necessary for
carrying on the work of the dock or ship, or for repairing any fencing.
If removed it shall be restored forthwith at the end of that period
by the persons engaged in the work that necessitated its removal.
Every 'person employed shall use the means of access provided in
accordance with the Regulations, and no person shall authorise or
order another to use means of access other than those provided in
accordance therewith.
No person shall go upon the fore and aft beams or thwartship
beams for the purpose of adjusting the gear for lifting them on
and off nor shall any person authorise or order another to do so.
LIFTING GEAR.
(а) All lifting machinery shall have been tested and examined by
a competent person in the manner set out in the Schedule to these
Regulations before being taken into use.
(б) (i.) All derricks and permanent attachments, including bridle
chains, to the derrick, mast and deck, used in hoisting or lowering
shall be inspected once in every twelve months and be thoroughly
examined once at least in every four years.
(ii.) All other lifting machinery shall be thoroughly examined once
at least every twelve months.
(iii.) For the purposes of this Regulation thorough examination
means a visual examination, supplemented if necessary by other
means such as a hammer test, carried out as carefully as the
conditions permit, in order to arrive at a reliable conclusion as to
the safety of the parts examined ; and if necessary for the purpose,
parts of the machines and gear must be dismantled.
(a) No chain, ring, hook, shackle, swivel or pulley block shall be
used in hoisting or lowering unless it has been tested and examined
by a competent person in the manner set out in the Schedule to
these Regulations.
562 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
(b) All chains, other than bridle chains attached to derricks or
masts, and all rings, hooks, shackles and swivels used in hoisting
or lowering shall, unless they have been subjected to such other
treatment as may be prescribed , be effectually annealed under the
supervision of a competent person and at the following intervals :—
Fig. 5.
A netboard for lifting small cased goods up to a maximum
weight of 25 cwt.
(i.) half inch and smaller chains, rings, hooks, shackles and
swivels in general use, once at least in every six months;
(ii.) all other chains, rings, hooks, shackles and swivels in
general use once at least in every twelve months,
(a) No rope shall be used in hoisting or lowering unless—
' (i.) it is of suitable quality and free from patent defect, and
TESTS FOR CARGO GEAR
563
(ii.) in the case of wire rope, it has been examined and tested
by a competent person in the manner set out in the
Schedule to these Regulations,
(6) Every wire rope in general use for hoisting or lowering shall
be inspected by a competent person once at least in every three
months, provided that after any wire has broken in such rope it
shall be inspected once at least in every month.
Fig. 6.
A chain slmg with hook. £ inch link, 16 to 24 feet long for slinging
cases. Maximum safe working load 6 d 2 tons, where "d” is the
diameter (m inches) of the iron of which the links are made.
6 x£"x£"=l£ tons.
(c) No wire rope shall be used in hoisting or lowering if in any
length of eight diameters the total number of visible broken wires
exceeds ten per cent, of the total number of wires, or the rope shows
signs of excessive wear, corrosion or other defect which, in the
opinion of the person who inspects it, renders it unfit for use.
(d) A thimble or loop splice made in any wire rope shall have
at least three tucks with a whole strand of the rope and two tucks
with one half of the wires cut out of each strand. The strands in
all cases shall be tucked against the lay of the rope. Provided that
564 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
this Regulation shall not operate to prevent the use of another form
of splice which can be shown to be as efficient as that laid down in
this Regulation.
No pulley block shall be used in hoisting or lowering unless the
safe working load is clearly stamped upon it.
Means shall be provided to enable any person using a chain or
wire rope sling to ascertain the safe working load for such chain or
sling under such conditions as it may be used.
(a) As regards chain slings, such means shall consist of marking
the safe working load in plain figures or letters upon the
sling or upon a tablet or ring of durable material attached
securely thereto.
(b) As regards wire rope slings, such means shall consist of either
the means specified in paragraph (a) above or a notice or
notices, so exhibited as to be easily read by any person
concerned, stating the safe working loads for the various
sizes of wire rope slings used.
Chains shall not be shortened by tying knots in them; and
suitable packing shall be provided to prevent the links coming into
contact with sharp edges of loads of hard material.
SAFETY PRECAUTIONS.
All motors, cog-wheels, chain and friction gearing, shafting, live
electric conductors and steam pipes shall (unless it can be shown that
by their position and construction they are equally safe to every
person employed as they would be if securely fenced) be securely
fenced so far as is practicable without impeding the safe working of
the ship and without infringing any requirement of the Board of
Trade.
Adequate measures shall be taken to prevent exhaust steam from,
and so far as is practicable live steam to, any crane or winch obscuring
any part of the decks, gangways, stages, wharf, or quay where
any person is employed in the processes .
'Appropriate measures shall be taken to prevent the foot of a
derrick being accidentally lifted out of its socket or support.
Precautions shall be taken to facilitate the escape of the workers
when employed in a hold or on 'tween decks in dealing with coal
or other bulk cargo.
HATCH BEAMS AND COVERS
565
When the working space in a hold is confined to the square
of the hatch, hooks shall not be made fast in the bands or fastenings
of bales of cotton, wool, cork, gunny bags or other similar goods,
nor shall can hooks be used for raising or lowering a barrel when,
owing to the construction or condition of the barrel or of the hooks,
their use is likely to be unsafe.
Nothing in this Regulation shall apply to breaking out or making
up slings.
When work is proceeding on any skeleton deck, adequate staging
shall be provided unless the space beneath the deck is filled with
cargo to 'within a distance of two feet of such deck.
Where stacking, unstacking, stowing or unstowing of cargo or
handling in connection therewith cannot be safely carried out
unaided, reasonable measures to guard against accident shall be
taken by shoring or otherwise.
The beams of any hatch in use for the processes shall, if not
removed, be adequately secured to prevent their displacement.
When cargo is being loaded or unloaded by a fall at a hatchway ,
a signaller shall be employed, and where more than one fall is being
worked at a hatchway , a separate signaller shall be employed to
attend to each fall.
Provided that this Regulation shall not apply in cases where a
barge, lighter or other similar vessel is being loaded or unloaded if
the driver of the crane or winch working the fall has a clear and
unrestricted view of those parts of the hold where work is being
carried on.
( When any person employed has to proceed to or from a ship by
water for the purpose of carrying on the processes , proper measures
shall be taken to provide for his safe transport. Vessels used for
this purpose shall be in charge of a competent person, shall not bo
overcrowded, and shall be properly equipped for safe navigation
and maintained in good condition.
There are various registration forms issued by the Home Office
to be filled in when winches, derricks, cargo blocks and gear have
been inspected. Particulars of the testing of any chain, ring, hook,
shackle or swivel, or any pulley, gin or block, is given on the certificate
granted by the firm authorised by the Home Office to carry out such
tests, the maximum safe working load of the several items being
specially mentioned. This certificate remains in force until the next
annual examination and annealling of chains, etc., is called for.
566
NIGHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
SCHEDULE.
Manner op Test and Examination before taking Lifting Machinery and
Gear into Use.
(a) Every winch with the whole of the gear accessory thereto (including
derricks, goosenecks, eye-plates, eye-bolts or other attachments) shall be tested
with a proof load which shall exceed the safe working load as follows :—
Safe working load. . Proof load.
Up to 20 tons. 25 per cent, in excess.
20-50 tons. 5 tons in excess.
Over 50 tons. 10 per cent, in excess.
The proof load shall be applied either (i) by hoisting movable weights or
(ii) by means of a spring or hydraulic balance or similar appliance, with the
derrick at an angle to the horizontal which shall be stated in the certificate of
the test. In the former case, after the movable weights have been hoisted,
the derrick shall be swung as far as possible in both directions. In the latter
case, the proof load shall be applied with the derrick swung as far as practicable
first in one direction and then in the other.
(6) Every crane and other hoisting machine with its accessory gear aha ]]
be tested with a proof load which shall exceed the safe working load as follows:
Safe working load .
Up to 20 tons.
20-50 tons.
Over 50 tons.
Proof load .
25 per cent, in excess.
5 tons in excess.
10 per cent, in excess.
The said proof load shall be hoisted and swung as far as possible in both
directions. In the ease of a jib-crane, if the jib has a variable radius, it shall
be tested with a proof load as defined above at the maximum and minimum
radii of the jib. In the case of hydraulic cranes or hoists where, owing to the
liimitation of pressure, it is impossible to hoist a load 25 per cent, m excess of
the safe working load, it shall be sufficient to hoist the greatest possible load.
(c) Every article of loose gear (whether it is accessory to a machine or
not) shall be tested with a proof load at least equal to that shown against the
article in the following table :—
Article of Gear.
Chain .
Shackle
Swivel
Proof load .
Twice the safe, working load.
Puaey Blocks :
Single Sheave Block
Multiple Sheave Block with safe work¬
ing load up to and including 20
t<was ..
}
Four times the safe wording
load.
Twice the safe working load.
QUADRENNIAL SURVEYS
567
Multiple Shea\o Block with safe woik-
mg load over 20 tons up to and
including 40 tons
Multiple Sheave Block with safe work¬
ing load over 40 tons . .
i
I
20 tons m excess of the safe
working load
One and a half times the safe
working load.
Provided that where the Chief Inspector of Factories is of opinion that,
owing to the size, design, construction, material or use of any such loose gear
or class of such gear, any of the above requirements are not necessary for the
protection of persons employed , he may by certificate m writing (which he may
in his discretion revoke) exempt such gear or class of gear from such requirement
subject to such conditions as may be stated m the certificate.
(' d) After bemg tested as aforesaid, all machines with the whole of the
gear accessory thereto and all loose gear shall be examined, the sheaves and
the pms of the pulley blocks being removed for the purpose, to see that no
part is injured or permanently deformed by the test.
(e) In the case of wire ropes, a sample shall be tested to destruction and
the safe working, load shall not exceed one-fifth of the breaking load of the
sample tested.
CLASSIFICATION SURVEYS.
To receive the distinctive mark 100 A1 in Lloyd’s Register,
the vessel must be surveyed periodically. Surveys become due at
4 years (No. 1 Survey), 8 years (No. 2 Survey) and 12 years (No. 3
Survey) from the date of build, a year’s grace being permitted in
“which to complete the survey. The conditions of survey are as
follows:—
SPECIAL SURVEY No. 1.
1. The vessel is to be placed on blocks of sufficient height in a
dry dock, or on a slipway; proper stages are to be made, and the
holds and peaks are to be cleared for examination.
2. In vessels having a single bottom the limber boards and
ceiling equal to not less than two strakes fore and aft on each side
are to be removed, one such strake being taken from the bilges.
Where the ceiling is fitted in hatches, the whole of the hatches and
one strake of ceiling at the bilges are to be removed.
3. The coal bunkers of steam vessels are to be cleared for
examination, and ceiling is to be removed as in the holds. The
bilges and limbers all fore and aft are to be cleaned out, so as to
allow of these parts being properly examined.
4. The framing and both surfaces of shell plating are to be
*568 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
exposed, and cleaned and coated where necessary. Special attention
should be given to the examination of the ash shoots, and the shell
plating in way of the openings.
5. In cases in which the inner surface of the bottom plating is
coated with cement or asphalt, the removal of this coating may bo
dispensed with, provided it be carefully inspected, tested by beating
or chipping, and found sound and adhering satisfactorily to the
steel.
6. If the vessel has a double bottom a sufficient amount of ceiling
is to be removed to enable the condition of the tank top to be
ascertained, and if it is found that the platmg is free from dirt and
rust, the removal of the remainder of the ceiling may, in the case
of the First Special Survey, be dispensed with.
7. The double bottom tanks are to be tested by a head of water
to the light water-line, but in no case less than 8 feet above the
inner bottom. Double bottom compartments, which are used for the
carriage of oil fuel, are to be tested by a head of water extending
to the load water-line, or by a head sufficient to give the maximum
pressure which can come upon, them in practice, whichever is the
greater.
Where peak tanks or other deep tanks for carrying water ballast
are fitted, their watertightness is to be tested by a head of water
not less than 8 feet above the crown of the tank.
All water ballast tanks are to be cleaned out to admit of their
being properly examined inside, special attention being given to the
tanks under the boilers.
All peak tanks, deep tanks and bunkers specially constructed
for carrying oil fuel are to be examined internally and are to be
tested by a head of water equal to 30 per cent, of the depth of the
tank, or 8 feet, whichever is the greater, provided the tanks are
fitted with overflows or other means to prevent a greater pressure
than indicated above. Where the tanks are not fitted with over¬
flows or other similar devices, they must be tested by a head
sufficient to give the maximum pressure which can be experienced
in practice.
In the case of motor and other vessels burning oil fuel and
carrying it in the double bottom and other tanks, upon the occasion
of the First Special Survey No. 1 these tanks, with the exception of
QUADRENNIAL SURVEYS
569
the fore and aft peak tanks,‘need not be examined internally,
provided upon a general external examination of the tanks the
Surveyor finds their condition to be satisfactory. In these cases
the tanks are to be tested by a head of water of not less height
than that stated above.
8 When a deck originally required to be 3 inches thick is worn
to inches, 2J inches to 2 inches, it is to be renewed. If, however,
such deck is found on survey to be in good condition the case will,
upon application, receive the consideration of the Committee.
9. The masts, spars, rigging, anchors, and general equipment of
steam and sailing vessels are to be examined and either found, or
placed, in good and efficient condition.
10. The hatch covers and supports throughout are to be
examined in position at the hatchways, and, if defective, are to be
renewed or made good.
The Surveyors should report on the efficiency of the tarpaulins,
cleats, and battens, or other means of securing the hatches.
The ventilator coamings and covers are to be examined, and
special care is to be taken to see that they are in an efficient
condition.
11. The steering engine and its connections, the telemotor gear,
the steering rods, chains, blocks, rudder, quadrant, tiller, steering
gear, windlass, pumps, sluice valves, watertight doors, and air and
sounding pipes are to be carefully examined, and their condition is
to be stated on the Surveyor’s report.
The Surveyor is to see that doubling plates are fitted under all
sounding pipes.
12. Where holds are insulated for the purpose of carrying
frozen or chilled meat, and the vessel in way of the insulation was
examined by the Society’s Surveyors at the time such insulation
was fitted, it will be sufficient at the first Special Survey No. 1 to
remove the limbers and hatches to enable the plating to be examined.
13. The freeboard recorded in the Register Book is to be verified.
14. The main and auxiliary engines and boilers are to be examined
and favourably reported on by the Society’s Engineer Surveyors.
U
570 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
SPECIAL SURVEY No. 2.
Survey No. 2 is the same as for Survey No. 1 and in addition—
The plating in way of the side-lights is to be examined, and if
the Surveyor deems it necessary he may require holes to be drilled
in any portion of the structure where signs of wastage are evident.
The chain cables are to be ranged for inspection, and the anchors
and chains are to be examined and placed in good working order.
If any length of cable is found to be reduced in mean diameter at
its most worn part it is to be renewed. The chain locker is to be
examined internally.
SPECIAL SURVEY No. 3.
All the requirements of Survey No. I and No. 2 have to be
complied with, and in addition all rust is to be removed from iron
and steel work throughout the ship, and the Surveyor is to satisfy
himself as to the condition of the plating which may, if considered
necessary, be drilled to test for thickness at places indicated by him,
afterwards all scaled and chipped parts to be coated.
All iron, steel and wooden masts, derricks, etc., are to be tested
by hammering, and, if considered necessary, drilled to test for
thickness of plating, etc. Mast wedges to be removed and replaced.
Where holds are insulated, inspection holes in the insulation
to be cut and frames and plating in the way of same to be examined.
The Machinery Survey is carried out periodically at the same
time as the hull survey. Boilers, however, when they are six years
old come under an annual survey.
The Steam Steering Engine and its connections, the steering
rods, chains, blocks, rudder, quadrant, tillers, steering gear, windlass
pumps, sluice valves, watertight doors, air and sounding pipes are
to be carefully examined, and the condition of same is to be stated
on the Surveyor’s report. The Surveyor must see that the doubling
plates are fitted under all sounding pipes.
Double Bottom Ta/iks.—The ceiling of double bottom is
removed and the efficiency of the tanks tested by a head of water
to the height of the load waterline. Peak tanks a,nd deep ballast
tanks are tested by a head of water not less than 8 feet (or 30 per
MERCANTILE MARINE OFFICE
571
cent, of depth of tank, whichever is greater) above the crown of the
tank. See remarks on water pressure on pages 363 to 372.
Subsequent Surveys.—The Second No. 1, No. 2 and No. 3
Surveys are due, respectively, when the vessel is 16, 20 and 24
years old, and the inspection increases in rigorousness witB the age.
SHIPPING OFFICE ROUTINE.
ENGAGEMENT OF CREW.
The master must produce the certificates of himself and such of
his officers, engineers and crew as require them, also the ship’s
Freeboard Certificate and Certificate of Registry.
The Articles must be dated and signed first by the master.
The Articles of Agreement (Form Eng. 1) must be in a form
approved by the Board of Trade, and two copies are signed—one
is retained by the superintendent, the other the master takes with
him.
The Agreement must specify the following particulars:—
(а) The nature, and as far as practicable, the duration of the
voyage, maximum period of engagement, and ports or
places to which the voyage is not to extend, and the
limits of latitude.
(б) The number and description of crew, and how many are
engaged as sailors.
(c) Time at which each seaman is to be on board, or to begin
work.
(d) Capacity in which each is to serve.
(e) Scale of provisions.
(/) Regulations as to conduct on board, fines, etc., for mis¬
conduct.
When the crew are duly engaged the superintendent issues to
the master a certificate which the master must produce at the
Custom House when clearing his ship outwards. This certificate
is the A.A. in the case of foreign going vessels, and the C.C. for
home trade vessels.
The master also receives the Official Log, a copy of the Articles,
the Return List (or Form Eng. 2), Abstract of Articles for placing
572
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
on board in a place accessible to the crew, Wages Account Forms,
and National Health Insurance Schedules
The Form Eng. 2 must, before finally leaving, be filled up and
sent to the nearest superintendent. It shows the changes made in
the crew (if any) since signing articles, and the names of those
shipped as substitutes for those who have not joined.
Penalty for failing to comply with this part of the Act, a sum not
exceeding £5.
Apprentices do not sign the Articles of Agreement, they are
bound to the shipowner for the period of their apprenticeship, but
their indentures are produced at the Shipping Office when the
crew sign on, and their names, ages, etc., entered on the Articles.
Failure to do so involves a penalty not exceeding £5.
Cadets, however, sign the Articles, as their agreement is for the
voyage only, just the same as other members of the crew.
Failure to Join.—Where a seaman has been duly engaged,
but after receiving and cashing an advance note wilfully or through
misconduct fails to join or deserts his ship before the note becomes
payable, he is liable to a fine of £5 or 21 days’ imprisonment. The
seaman gets someone to advance to him the amount of money therem
stated and to endorse the note to that effect. The person who
advances the money is repaid by the shipowners on presenting the
note so many days, usually three, after the ship has sailed, pro¬
vided, of course, that the seaman goes in the ship.
Articles for more than One Voyage.—Coasting Articles for
home trade ships and Running Agreement Articles for vessels on
short voyages to ports situated just beyond home trade limits
may be opened to avoid the delay of paying off and signing on
again at frequent intervals. Such articles do not extend for a period
exceeding six months and terminate automatically on the last day
of June and December, three weeks’ grace being allowed in which
to return them to the Mercantile Marine Office.
The home trade applies to vessels trading within the following
limits:—The United Kingdon, the Channel Islands, the Isle of
Man, and the Continent of Europe between the River Elbe and
Brest inclusive.
Certificated Officers.—Certification of officers and engineers
in home trade cargo ships is not compulsory, but all foreign-going
MERCANTILE MARINE OFFICE
573
vessels and home trade passenger vessels must carry a duly
certificated master; and all such vessels of 100 tons burden and
upwards must also carry a duly certificated mate in addition to the
master. Foreign-going vessels carrying more than one mate must
have at least the first and second mates duly certificated.
Foreign-going steamships of 100 N.H.P. or upwards must have
at least two engineers, one first class and one second class, duly
certificated, and foreign-going steamships and home trade passenger
vessels of less than 100 N H.P. must have at least one certificated
engineer.
DISCHARGING THE CREW.
The master must pay to each seaman, on the lawful termination
of his engagement, two pounds (£2), or one quarter of the amount
of wages due to him, whichever is least. The crew to be paid off
within two clear days (Sundays, holidays, etc , not counted).
The master must deposit the Articles and Official Log within
48 hours of arrival; or when paying the crew off, if that takes
place within 48 hours.
On the satisfactory closing of the Articles the superintendent
must deliver to the master a certificate to that effect (the B.B.).
The B.B. must be produced to the officer of Customs when the
ship is cleared inwards (see Custom House Regulations).
Dispute on Paying Off.—Any question of whatever nature and
whatever the amount in dispute between a master or the owner
and any of his crew if raised before a Superintendent of a Mercantile
Marine Office, and both parties agree in writing to submit the same
to him. The Superintendent shall hear and decide the question
submitted, and his decision shall be conclusive.
Seaman left behind in Hospital.—The man’s wages and
effects, together with a list of same in duplicate, one for the patient
and one for the Consul, are handed to the British Consul and
sufficient money is left to cover all the man’s expenses. This is all
carefully recorded in the Official Log. The British Consul attends
to the repatriation of the man when he is discharged from hospital.
Ship Abandoned.—In the event of shipwreck the crew are
entitled to two months’ pay from the date of abandonment, unless
574 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
they are offered and accept equivalent employment in another
ship.
Period of Agreement Expiring Abroad.—If the date of term¬
ination of the Articles of Agreement occurs when the vessel is abroad,
the Consul may grant an extension of the period, but if not it then
becomes a question of a mutual agreement between the master
and the crew regarding rate of wages. Failing an agreement on the
point, the crew must be repatriated and wages paid up to the date
of their arrival home, $
Deserters.—A seaman is said to be a deserter when he
unjustifiably leaves a ship in the course of a voyage or engagement
without having been discharged and with the intention of not
returning
In the event of any of the crew deserting the ship, notice should
at once be given to the Local Authorities (Police) with a full
description of the men and any other useful information having a
view to their arrest and return to ship. In many places the ship is
liable to a heavy fine if they remain ashore.
Take the Articles to the Shipping Master or Consul and have
them endorsed with a certification that the reason of the men being
left behind is desertion. This is very important, as otherwise the
deserter will probably become classed as a “ distressed seaman ”
and as such the owner will become liable for repatriation expenses.
Make an entry in the official log book of the fact and details of
the desertion, also a list of the effects left on board and the amount
due on account of wages.
Deserters forfeit all the wages they have earned and any effects
they may leave on board. Their effects must be handed over to
the Superintendent of a Mercantile Marine Office at the end of the
voyage within 48 hours of arrival, also their wages less all expenses
incurred in engaging substitutes. These expenses must be set out
in a “ re-imbursement ” account form provided by the Board of
Trade, and should be supported by vouchers whenever possible.
In this account may also be included the amount paid to the
substitutes beyond what the deserters would have earned.
The Consul may order the effects left behind by deserters in a
foreign port to be sold, in which case the amount realised, less the
expense incurred, is handed to the Consul. The master or owners
MERCANTILE MARINE OFFICE
^75
are entitled to be re-imbursed for any sum properly chargeable
against deserters, and the balance, if any, is paid into the Exchequer
through the Board of Trade.
Joining the Navy.—If a seaman leaves his ship to enter the
Naval Service forthwith and is accepted for such service, he is not
deemed to be a deserter. The master shall deliver to him his effects
and pay any balance of wages to the naval officer who receives the
seaman, and who shall give the master a receipt for same. Should
the seaman be in debt to the ship, the owner can recover the amount
from the Accountant General of the Navy.
Distressed British Seamen.—British Consular officers and
other officers of His Majesty in foreign countries are empowered to
provide maintenance for distressed British seamen found abroad
and to put them on board a British ship bound to the United
Kin gdom or to the British possession to which the seaman belongs.
But should a British ship in the port be in want of men to make
up its full complement, the Consul should, of course, endeavour
to ship the men back under “ Articles ” and not as distressed seamen.
The master of a British ship is bound by the Merchant Shipping
Act to take on board his ship any distressed British seamen, but
not necessarily more than one for every 50 tons burden, and to
provide them with proper accommodation and food.
The master must make a sworn declaration giving all particulars
of the men and the number of days they have been on board the
vessel, the full complement of the ship’s crew must also be stated.
The owner is paid out of the Mercantile Marine Fund for every day
the distressed seamen have been on board, but only for those
distressed British seamen in excess of the normal complement of
the ship.
OFFICIAL LOG.
The master is responsible for the Official Log being properly
kept. The draught and freeboard must be entered whenever leaving
port. A list of the entries required to be made is given at the
beginning of the log book.
Amongst these the principal are :—
Offences committed by any member of the crew, or conviction
by any legal tribunal.
576 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Any offence for which punishment is inflicted on board, and the
punishment.
The names, also a statement of the conduct, character, and
qualifications of each member of the crew, or a statement that the
master declines to give an opinion on these particulars.
Every case of illness ; the treatment adopted, etc.
Every case of birth, death, or marriage.
Every change of crew during the voyage.
The amount of wages due to any seamen who enters His Majesty’s
service.
The wages account of any seaman or apprentice who dies during
the voyage, including a statement of each article sold, and the
amount received for it
Every collision with any other vessel.
A statement of every occasion on which boat drill is practised
on board the ship, and on which the hfe-saving appliances on board
have been examined to see if they are fit and ready for use. It
must be shown to any officer of the B O.T. on demand. Penalty
for infringement, £10.
When entries are made in the Official Log, they must be made
as soon as possible after the occurrence to which they relate, and
must be dated. Entries made in respect of an occurrence happening
before the arrival at the final port of discharge must be made within
24 hours of arrival.
AH entries must be signed by the master and by the mate, or
some other member of the crew.
In the event of disrating or penalising a member of the crew
for incompetency or misconduct, the entry in the Official Log must
be read over to him and a copy of the entry must be given to the man.
The amount of any fines imposed must be paid over to the Superin¬
tendent of the Mercantile Marine Office.
The Official Log is returned to the Mercantile Marine Office
on the termination of the Articles of Agreement; or on the transfer
of ownership if the ship is abroad, or if the ship be lost or abandoned.
Death at Sea.—In the event of a member of the crew or a
passenger dying at sea, the master must make a full and detailed
entry in the Official Log Book, and, if there is not a qualified medical
MERCANTILE MARINE OFFICE
577
man on board, he should describe the person’s illness, or accident,
as the case may be, the treatment adopted, etc., the exact time of
death and the ship’s position at the moment.
The entry to be signed by the Chief Officer and by some of the
friends of the deceased person, especially by any of the men who
had been detailed to look after him. The ship should be stopped and
Christian burial conducted.
The property and money due to a deceased seaman is delivered
to the Superintendent of a Mercantile Marine Office within 48 hours
of ship’s arrival at a home port. But if the effects are sold on board
by public auction an accurate entry giving the following particulars
must be made in the Official Log and duly signed by an officer and
a member of the crew.
(а) A statement of the amount of the money and a description
of the effects.
(б) A description of each article sold and the sum received for
each.
(c) A statement of the sum due to the deceased for wages and
the amount of deductions (if any) to be made from the
wages.
CASUALTIES-
44 Courts of Enquiry,”—In the event of a shipping casualty,
the Board of Trade usually hold a preliminary inquiry on the result
of which the Board may order a formal investigation into the
circumstances to be held before a Commissioner of Wrecks, who
will be assisted by nautical assessors appointed by the Home Office.
The Legislature of any British possession has also power to
authorise a tribunal to make inquiries as to shipwreck or other
casualties affecting ships, or as to charges of incompetency or mis¬
conduct of masters, mates and engineers.
44 A Naval Court” may be summoned by a commanding
naval officer on any foreign station, or by a Consular officer, whenever
a complaint of serious breaches of discipline which appears to that
officer to require immediate investigation is made to him by the
master of a British ship, or officers or members of the crew; when¬
ever the interest of the owner or of the cargo thereof appears to
578 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
require it; and into any cases of the wreck or abandonment of a
vessel.
The Naval Court must be properly constituted, and shall consist
of at least three members, one of whom shall be a naval officer not
below the rank of Lieutenant, one a Consular officer, and one a
British shipmaster.
These several courts have similar powers and may cancel or
suspend the certificates of masters, mates and engineers, remove any
members of the crew, impose fines and punishment for mis¬
demeanours ; in short, all the powers of a court of summary
jurisdiction.
“ A Court of Survey ” consists of a judge or magistrate and
two assessors, either nautical or engineer, or persons having special
qualifications to investigate the question at issue.
The Court deals with complaints regarding the seaworthiness
of the vessel and her equipment and cargo, and has powers to
order the inspection of every part of the ship, the removal of her
cargo, and to detain or release the ship as the court may decide.
A ship may be “ unseaworthy ” in ways other than that of
structural weakness ; for example, a ship having masters or officers
without the necessary qualifications, or being undermanned, or being
short of bunker coals, provisions, stores or any part of the usual
and necessary equipment, is not in “ every way fitted for the voyage ”
and is therefore technically “ unseaworthy.”
The cases which most frequently come before courts of summary
jurisdiction in this country are breaches of the Regulations of the
Factory Act as applicable to the loading and discharging of cargo;
failure to comply with the requirements of medical officers re crews’
quarters, etc.; throwing refuse overboard within the limits of a
port; oil pollution of harbours ; overloading ; carrying an excessive
or improper deck load ; smuggling by members of the crew, etc*
CHAPTER XX.
SHIP’S BUSINESS.
Modern shipping business is transacted with greater rapidity
than formerly due to the development of telegraphic communication
between ships at sea and land stations, thus enabling the owner
to keep in constant touch with the shipmaster so, nowadays, it is
seldom that the master of a ship is called upon to transact business
as if he were the sole representative of the ship completely cut
off from the shipowner, consignees or agents, and acting on his
own initiative. Most of the business is done by the owners’
authorised agents, who make the necessary arrangements pending
the ship’s arrival, and often complete the essential documents
after she has sailed. This is particularly the case in cargo liners
owned by firms that grant through bills of lading from the place of
origin to destination, no matter how far inland they may be, the
forwarding business being transacted by the owners’ agents at the
various places of transfer where the goods may be handled. But
the system of examination in the commercial and legal duties of
shipmasters assumes that the candidate is not merely master of the
vessel but, in effect, the owner also, and, as such, he is expected to
approach all matters connected with the transaction of the ship’s
business, whether it be of an ordinary or of an extraordinary
character, with prescience, and to act to the best of his ability as
if the ship and cargo were uninsured and belonged solely to himself.
Every shipmaster should have a copy of the Merchant Shipping
Act at hand for reference in cases of doubt or difficulty.
For convenience of reference the following subjects have been
arranged in alphabetical order:—
A. A.—A certificate given to the master of a foreign-going vessel
by the superintendent of the shipping office. It certifies that the
master has engaged his crew and has produced the ship’s register,
his certificate, officers* and engineers’ certificates, load line certificate,
579
680 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
apprentices’ indentures, etc. The A A. has to be produced at the
Custom House for clearance outwards.
Advance Notes.—The Merchant Shipping Act provides that a
seaman may, conditionally on his going to sea in pursuance of his
agreement, receive an advance note for a sum not exceeding the
amount of one month’s wages. Note that this is different to an
i( allotment ” note. The seaman cannot claim an advance note if
the master desires to withhold it.
Allotment Notes.—A seaman may claim an allotment note
of any part (not exceeding one-half) of his wages in favour either of
a near relative or a savings bank. The Superintendent or other
officer before whom the seaman is engaged, shall, after the seaman
has signed the agreement, inquire if he wishes to have an allotment
note ; and, if he does, shall insert such fact in the agreement with
the crew, and it shall be deemed to have been agreed to by the
master.
The master has the option of advancing cash and granting
shore leave in a foreign port, and should a seaman want to send home
part of his wages and the master decides to grant him facilities for
doing so, then the master may give him a note on the owners for the
amount, enter it in the man’s account of wages, and get his receipt
for it. *
Average.—There are two kinds of average, “ Particular ” and
" General.”
Particular Average represents an accidental loss arising
from some peril insured against, such as loss of masts or spars
through stress of weather, damage to hull or machinery through
fire, collision, or stranding, etc.
Particular average losses are borne by the parties on whom
they fall; that is, there is no general contribution by all concerned.
In the case of an accident affecting the ship only, the cargo owners
do not contribute, and vice versa .
Particular average losses are not recoverable from the under¬
writers unless they amount to 3 per cent, on the value insured.
Shipowners, however, usually cover small damage up to 3 per cent,
by insuring in Mutual Clubs and Protection Associations, the
members’ contributions being collected by ** calls ” on the ship-
VORK-ANTWERP RULES
581
owners, the amount being determined annually by the total tonnage
of the ships owned by the firm and the extent of the claims paid by
the Mutual Insurance Association.
General Average arises when some loss or expense has been
wilfully and voluntarily incurred in order to save the ship and
cargo, or what remains of them. It is termed “ General,” because the
loss is borne generally by all interested in the ship, freight and
cargo, each one’s share of the loss being proportioned to the value
he had at stake.
York-Antwerp Rules.—These form a code of rules for the
settlement of cases of General Average, and are now universally
adopted. They only apply, however, when expressly agreed upon
in the charter-party and bills of lading. Where this is not done the
average would be settled according to British law, which differs
from the York-Antwerp Rules in one or two respects.
The Rules define broadly what may or may not be made good
under general and particular average, and they serve as a guide to
average adjusters in deciding how the various interests involved in
the venture shall contribute their financial share of the loss.
The rules are recorded under the headings of :—Damage to ship
and cargo in consequence of jettisoning cargo. Jettison of deck
cargo is not made good as general average.
Extinguishing fire on shipboard and the resultant damage by
fire and water.
Cutting away wreck.
Voluntarily running the ship ashore to avoid total loss or greater
Damage to engines in the endeavour to refloat.
Expenses incurred in lightening a ship when ashore.
Cargo and material burnt for fuel if ship runs short of bunkers
through unforeseen circumstances.
Expenses at port of refuge in discharging, storing and reloading
cargo and damage to cargo during the process.
Wages and maintenance of crew in port of refuge.
Loss of freight, etc.
Average Adjuster is one whose special business it is to make '
out and draw up statements of general average, showing the amounts p
582
NICHOLLS~S SEAMANSHIP AND NAUTICAL KNOWLEDGE
payable by each party. The appointment of the average adjuster
lies with the shipowner or master.
Average Bond.—This is an agreement between the master of
a vessel and the consignees of the cargo, whereby they agree to pay
to the master their respective proportion of the average when
adjusted. The shipowner is entitled to require a deposit in advance,
in addition to, or in place of the Average Bond.
Whenever a case of General Average arises, the master should
get the Average Bond signed before delivering up the cargo, or see
that proper security for the payment is obtained from the
consignees.
Barratry.—Any illegal or fraudulent act wilfully committed
by the master or any member of the crew to the prejudice of the
shipowner. Examples—Smuggling without consent of owners;
fraudulent dealing with ship and cargo ; wilful resistance to a right
of search ; wilful breach *of blockade ; sailing from a port without
leave in breach of an embargo.
B. B.—A certificate issued at the shipping office certifying that
the master has deposited his “Articles” and Official Log Book with
the Superintendent; has accounted for the whole of his crew;
and, if any of the seamen have died, that he has settled the accounts
for their wages and effects. The B.B. must be produced to the
Customs Officer when the ship is cleared inwards.
Bill of Exchange.—A bill of exchange is an unconditional order
in writing, addressed by one person or firm to another, requiring
them to pay a certain sum of money to a person named on the
bill, or to bearer. The bill may be made payable on demand, or at
a certain number of days after sight.
(Specimen.)
No. 9515. The Bank of London,
London, April 28, 1936.
Sixty days after sight of this First of Exchange (second and
third of same tenor and date being unpaid), pay to the order of
B. S. & F. two hundred pounds sterling value received.
For the Bank of London,
J. R. SMITH, Manager .
To the Bank of Adelaide,
Adelaide, S. A.
BILL OF LADING
m
\
A bill of exchange 'which is payable at a fixed number of days
after sight must be first presented for acceptance. The person
or firm to whom it is addressed, if they accept it, will write the
word ‘ ‘ accepted * ’ across the face of the bill, and duly sign
and date the acceptance At the expiration of the specified number
of sight days the bill is said to have matured, and is then payable.
There are, however, always three days of grace allowed beyond the
sight days, if required by the acceptors
An inland bill of exchange is one drawn and payable in the same
country; any other is a foreign bill.
A bill of exchange which is payable on demand or at sight must
be paid when presented, no days of grace being allowed in this case.
4 If the holder of a bill of exchange, payable at some future date,
wishes to realise the money before that date, he can, if the bill be a
good one , get it discounted ; the banker who discounts it will pay
him the money, minus the discount at the current rate of interest.
Bill of Health.—A document stating the health of the port
with respect to infectious diseases at the time of the vessel’s
departure. There are three kinds: clean, suspected and foul.
British ships obtain their bills of health from the British Consul
when leaving a foreign port, and from the Custom House when
leaving a British port. It must be officially stamped or signed by
the Consul of the country to which the ship is bound.
Bill of Lading.—A stamped document, usually signed by the
master acknowledging the receipt on board, of the goods described
in the bill, and undertaking to deliver them at the port of destination.
Requires a sixpenny stamp, which must be an impressed and not an
adhesive stamp . It must be stamped before being signed. Penalty
for signing an unstamped bill of lading, £50.
At the time of signing the bill of lading, the mate’s receipt for
the goods referred to in the bill should be produced, and the master
should see that the bills accurately correspond to the mate’s receipt
before signing them. The mate’s receipts should bo preserved and
retained by the master.
Generally (but not always) there are three bills of lading to a
set. In all cases the number to be signed by the master is stated
at the foot of the bills. An unstamped and unsigned copy is retained
by the master for future reference.
584
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
The master should, before signing bills of lading, see that they
are consistent with the charter-party, and that the interests of the
ship are duly protected by the insertion of such clauses as may be
necessary in respect of the nature of the goods
If the freight as per the bill of lading is less than that in the
charter-party, the master should refuse to sign them unless the
difference is made good in cash before signing This would not
apply if the charter-party states that the master “is to sign bills
of lading at any rate of freight without prejudice to the charter-
party/'
After reaching the port of destination the cargo must be delivered
to the party presenting the bill of lading, duly indorsed by the
shipper. The master should retain the indorsed bill of lading.
When writing out a set of bills of lading for signature, an extra
copy is made out, but it is left unstamped and unsigned, and across
it is written “ Captain’s Copy.” This copy is carried in the ship
for the captain’s information, also to ensure that no fraudulent
alteration has been made in the signed documents, and also for
production on demand if boarded by a belligerent visiting officer.
Protective Clauses.—It is essential in dealing with the question
of shortage, pillage and damage, that the general terms of the bill
of lading is understood. A clean bill of lading is a shipowner’s
agreement to deliver the package in the same good order and
condition as when received, and unless exception is taken to the
package at shipment and the bill duly claused, the ship is responsible
for any shortage or damage occurring. In loading cargo, therefore,
the officers should keep a strict watch for cargo that is not in
sufficiently sound condition to enable it to stand the stress of the
voyage and handling, and then allow it to be delivered to the
consignee intact.
Clauses can be added to the bills of lading in accordance with the
mate’s receipts and are a protection in the event of claims arising.
Such clauses as frail package, renailed, unprotected, contents rattling,
skeleton cases, dented, old bags, resewn bags, ullaged, contents
leaking, rusty, stained and wet, etc., as the case may be.
The number of packages so queried should be specifically stated,
giving the marks, numbers, etc., for identification purposes.
In bills of lading issued for optional ports the destination must
CHARTER-PARTY
585
be declared by the consignee forty-eight hours before the vessel
arrives at her first port, otherwise this cargo will be landed at the
first port mentioned in the bill of lading, unless a special condition
is attached to the bill.
Bottomry Bond.—A bill, by means of which a ship or the
freight she earns is pledged in return and as security for money
advanced.
A bottomry bond must only be raised when it is impossible to
obtain credit, or to raise money by giving bills on the owners. It
must be clearly a case where the money is necessary to enable the
ship to proceed to her port of destination. Money advanced to the
master on a bottomry bond must only be expended on what is necessary
for the continuance and completion of the voyage.
More than one bottomry bond may be raised if circumstances
arise rendering it necessary. The last raised must be repaid first.
If the ship is lost before reaching her port of destination, the
lender loses the money advanced. If she arrives, he is repaid the
amount, plus the agreed upon interest or premium.
C. C.—A certificate for the coasting trade, corresponding to the
A.A. certificate for foreign-going vessels.
Charter-party.—A charter-party is a contract or agreement
whereby a shipowner or master covenants for the use of the ship
by the charterer for a specified voyage or time.
Special forms of charter-party are in use for particular trades or
voyages ; but in all charter-parties the master or owner warrants
the ship to be tight, staunch, and strong, and fitted for the voyage—
i.e., she shall be seaworthy.
The following are some of the principal points which generally
appear in charter-parties:—
Freight Clause.—Stipulating the amount of freight, and when
and how it is to be paid.
Lay Days or Hours. —The charter-party specifies the number
of lay days or, in some cases, the number of hours, in which the
cargo is to be loaded and discharged. It also specifies the kind of
lay days or hours, i.e., whether “ working ” or “ running ” days, etc.
If “ working ” days, then all the days on which it is not usual to
work, at the port where the ship is, axe not counted. If “ running ,r
days, then every day counts. “ Weather working ” days are some-
586
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
times specified, and in others a definite date is fixed by which time
the cargo is to be loaded.
Demurrage.—If the ship is not loaded or discharged at the
expiration of the lay days, and delay arises from the fault of the
charterer or his agents, the charter-party specifies that he must
pay a fixed sum per day or hour for the time the ship is
detained. This payment is termed 44 demurrage.” It must
be claimed daily, and the claim for Sundays must be made on
Saturday. Generally the charter-party specifies the number of
days during which a ship can be kept on demurrage, and states
that at the expiration of the demurrage days the ship is to be at
liberty to sail, full or not full, and if not fully loaded the charterer
is to pay “ dead freight ”* on the shortage. This, however, depends
upon the actual wording of a charter-party
Despatch Money is the reverse of demurrage. It is a sum of
money paid by the shipowner to the charterer for despatching the
ship before the expiration of the lay days.
Floating Clause.—This stipulates that the ship shall proceed
to her port of destination, or as near thereunto as she can safely
get, where she can safely lay afloat at all times and tides.
Deviation from Voyage.—The charter-party specifies that the
ship must proceed direct to her port of destination j that is, she
must not deviate unnecessarily from her course.
Deviation and Towing Clause.—This is a clause usually
inserted in steamers’ charter-party, giving them liberty to tow or
be towed, or to assist other vessels, and to deviate, if necessary, for
this purpose. Without this clause a vessel would only be justified
in standing by another in distress, in order to save life, and not
with the view of earning salvage.
Exceptions or Negligence Clause.—By this clause the ship
is excepted from responsibility for act of God, perils of the sea,
fire, etc. The following negligence clause is copied word for word
from a Welsh coal charter-party :—“ The act of God, the King’s
enemies, restraints of princes and rulers, and perils of the seas
excepted. Also fire, barratry of the master and crew, pirates,
collisions, standings and accidents of navigation, or latent defects
♦See “ Dead Freight,”
BARTER-PARTY
587
in, or accidents to, hu) an d/ or machinery, and/or boilers, always
excepted, *even when e&sioned by the negligence, default, or error
in judgment of the^°^> master, mariners, or other persons
employed by the or for whose acts he is responsible,
not resulting, howeA m any case from want of due diligence by
the owner of the sib or by the ship’s husband or manager.”
Penalty GW e *—This clause specifies the penalty for non¬
performance. jb usual penalty is proved damages not exceeding
the estimated f&ount of freight,
if the shi/is likely to have to discharge into lighters, there
should be a <ause specifying on whom the expense of lighterage is
to fall j
A cha^r-party requires a sixpenny stamp to make it legal.
■ An a Jesive stamp may be used if affixed before signing, and
w&st be ? cancelled by the last person signing.
6 A c^iter-party may be stamped with an impressed stamp, after
bing f gned upon the following terms ■ —
)f Within seven days, on parent of duty and a penalty of
, 4s. 6d
‘h. After seven days and ■within one month, on payment of
/ duty and a penalty of £10
f 3. A charter-party first executed abroad may be stamped
# within ten days after it has been received in the United
' Kingdom, or before it has been signed by any person in
' the United Kingdom.
| The charterers should be notified in writing when
* the ship is ready to receive cargo,
! A charter-party only comes into operation when one man or
/ firm owns a vessel and another man or firm charters her. When
1 an/owner or a regular line of steamers send a vessel of their own
or a voyage, a charter-party, of course, is not required.
* Commission.—The amount payable to a shipbroker when he
is the medium through which the charterers and shipowners are
introduced to each other. It is calculated as a percentage on the
freight payable on the charter-party.
Commission is also a term denoting the amount payable to agents
for transacting ship’s business.
Address commission is commission payable at port of discharge.
PP|fl S OTCHOtLS’S SEAMANSHIP AND KNOWLEDGE
IS
Consignee* — The person or firm ^
consigned, that is, the one authorised
agents are authorised to act for the owm^ a ' TOgge | j n a foreign
port, they are termed the “ consignees of
cm goods or cargo
receive them. Where
Constructive Total Loss.—A vessel is . nstrucl i ve total loss
when she is so badly damaged that the cost e p air i ng her would
exceed her value when repaired. A survey ^ ie vesse l should
be held and an estimate of the cost of repairs a | nec f Also, the
master should get a certificate stating what woi •j De ^e va j ue G f
the vessel if repaired. The report of surveyors, c na ^ e Q f cos ^ Q f
repair, and certificate, should be sent to the owners
Where a vessel becomes a constructive total los^ e £ Wne r is
entitled to claim for a total loss supposing the vesseh msur ed.
It must, however, be clearly proved that the vessel > ac tuallv a
constructive total loss, and that her condition is sue that \he
shipowner himself, if the vessel was uninsured, would m attempt
to repair or refit her.
CUSTOM HOUSE REGULATIONS (BRITISH
Entering Inwards.—The master of every vessel, e th»>r
laden or in ballast, must, within 24 hours of arrival at any port
in the United Kingdom, make due report of such vessel the.
Collector of Customs, and such report (except in cases speedily
provided for) must be made before breaking bulk. Penalty for >ot
reporting or for false report, £100.
Papers Required.—The papers required are register, nanifet
of cargo and stores, certificate of pratique,* and last ligh ■ bib,
also, if a grain-laden ship, the grain certificate. \
Masters have also to state at the time of reporting whether vhey
have passed any dangers to navigation such as wreckage, dereict 1
vessels, or ice, and if so to specify particulars. Also to make v a
declaration that all letters (if any) carried by the ship have beei
delivered to the Post Office.
Clearing Inwards.—When the inward cargo is discharged the
Customs Examining Officer finally rummages the vessel and checks
the stores remaining on board. He then calls on the master or person
* Obtained from the Customs officers at the landing station on entering
the port.
CUSTOM HOUSE
589
in charge of the vessel for the B.B.* certificate, and on its production
he issues the inward clearing bill or jerque note.
Entry Outwards.—No outward cargo must be shipped until
the ship is entered outwards at the Customs. In entering outwards
the jerque note mentioned above is supposed to be produced.
The practice, however, varies at different ports, and in large ports
the ship may, if necessary, be entered outwards previous to the
discharge of the inward cargo, the Customs officer on board tailing
care that no outward cargo is shipped until complete separation
between it and any mward cargo remaining in the vessel is assured.
Clearance Outwards.—The master must produce the following
documents:—
The register.
The outward light bill, receipted.
The A.A. certificate if a foreign-going ship, the C C. if in the
home trade.
He must also answer any questions asked by the Collector of
Customs relating to the ship, cargo, or voyage, and make a declaration
of the contents of cargo and stores.
The clearance label (or cocket card), with the victualling
billf attached, which form the clearance and authority for the
departure of the ship, are then signed and given to the master.
Vessels leaving in ballast do not have to produce the outward
light bill receipt, unless carrying passengers, as they are exempt.
The inward light bill receipt must, however, be produced.
Bills of health are issued at the Customs Clearing House when
required.
Dead Freight.—Freight paid on vacant stowage space, i.e.,
when the amount of cargo shipped is less than the amount specified
in the charter-party. The shipowner is entitled to freight on the
shortage, just the same as if the ship carried it, and this is termed
“ Dead Freight ”
Derelict.—The master of every British ship, who shall become
aware of the existence on the high seas of any floating derelict
* See BJB.
t This is a document showing the bonded stores on board shipped solely
for the vessel’s use.
590 NICHOLLS.S SEAMANSHIP AND NAUTICAL KNOWLEDGE
vessel, must notify the same to the Lloyd’s agent at his next place
of call on arrival. He must also give all such information as he may
possess regarding the supposed locality or identity of such derelict
vessel, the date and place where she was observed, etc.
The penalty for failing to make such a report is a sum not
exceeding £5.
Disbursements.—Money disbursed by the master in financing
the ship. Vouchers are receipts preserved by the master for
production to the owners, along with his disbursement account.
The agents in a foreign port usually advance money to the
master as cash for current expenditure, or there may be a balance
of freight to draw upon. But if neither of those means are available
and there are considerable expenses to be met, then the master
may give the creditor * a f< bill ” on the owners
Grain Certificate.—Before a British ship laden with a grain
cargo at any port in the Mediterranean or Black Sea, and bound
to ports outside the Straits of Gibraltar, or laden with gram cargo
on the Coast of North America, leaves her final port of loading, or
within 48 hours after leaving that port, the master shall dehver,
or cause to be delivered to the British Consular officer, or if the port
is in a British Possession, to the chief officer of Customs at that
port, a notice stating:—
(а) The draught and freeboard after the loading of her cargo
has been completed.
(б) 1. The kind of grain and the quantity thereof.
2. The mode in which the grain cargo has been stowed.
3. The precautions taken against shifting.
When arriving at a port in the United Kingdom the master shal
also deliver a similar document to the proper officer of Customs
This is done when the vessel is entered in at the Custom House.
Penalty for failing to make this report, or for making a fals<
statement, a sum not exceeding £100 (Merchant Shipping Act
1894, Section 454).
Insurance Policy.—An agreement containing the condition
under which a ship is insured, and the perils she is thereby insure<
against. The policy is nullified if—
The ship deviates from her voyage.
If she be engaged in any illegal trade.
If she was unseaworthy at the time of insuring.
MARINE INSURANCE
591
The underwriters are those who render themselves liable for the
insurance by signing or underwriting their names at the foot of the
policy There is usually a clause at the foot of a policy excluding
claims which do not amount to 3 per cent, of the value insured.
It is very important where a vessel has put into port in distress
to have a certificate of seaworthiness before leaving.
Warranties.—Where a ship in an insurance policy is warranted
to sail on or before a date named. Other clauses in an insurance
policy are also termed warranties ; for example—the ship and freight
are warranted free from average under 3 per cent., unless general,
or the ship be stranded.
Invoice.—A list of goods, cargo, or stores, with the original
prices of each, and intermediate charges, such as freight, insurance,
etc.
Jetsam.—Goods or cargo cast into the sea for the preservation
of the ship and remainder of cargo, the ship being lost afterwards,
notwithstanding the effort made to save her by relieving her cargo.
Jettison.—The act of throwing goods overboard for the safety
of the ship. When such goods sink to the bottom and are buoyed
by those throwing them over, the term *'‘ Ligan ” is applied to
them.
Flotsam is the term applied to goods which are left floating when
a vessel is lost or wrecked.
Jerquing.—A Custom House term denoting the final examina¬
tion of the accounts of the cargoes landed by vessels.
Jerque Note.—When a vessel has discharged the whole of her
cargo she is finally rummaged by the Customs officer, who also
overhauls and checks stores, etc. If all is in order he issues the
inward clearing bill, or jerque note.
Lien.—A legal right over property, or goods, to hold it until
the claim against the owner of it has been satisfied. The shipowner
has a lien on the cargo for freight unless the charter-party states
the reverse, and if the freight is not paid the owner or master of the
ship may warehouse the goods, giving the wharfinger or warehouse¬
man a written notice that they are to be retained until the lien is
discharged.
At the expiration of ninety days (or at an earlier date if the
592
NTCHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
cargo is a perishable one) ihe goods may be sold by public auction,
but notice of the sale must be duly given, by advertisement in the
local newspapers. The expenses of warehousing must be borne by
the owner of the goods The owner has no hen on the cargo for
demurrage or dead freight unless stated in the charter-party.
Maritime Lien.—The lien which the master and crew have on
a vessel for their wages. The master also has a lien for any necessary
expenses he has incurred on behalf of the vessel.
Light Dues.—A charge levied upon vessels for providing and
maintaining the lighthouses, vessels, beacons, buoys, etc., for the
benefit of shipping and navigation.
A vessel entering for bunker fuel only—providing she has not
broken bulk, or taken on board mails, cargo or passengers, or called to
receive orders—is exempt from light dues.
Vessels in distress, vessels navigated wholly and bona fide in
ballast, several classes of small vessels, His Majesty’s ships, and ships
belonging to foreign Governments, are also exempt. (See Second
Schedule to Merchant Shipping Act, 1898.)
A receipt for light dues must be given to the person who pays it,
and a ship may be detained at any port until this receipt is produced
to the officer of Customs.
Lime Juice.—One ounce each man per day to be served out to
the crew as soon as they have been at sea ten days.
Lloyd’s Agent.—In all parts of the world the Corporation of
Lloyd’s have agents. One of their duties as agents is to render
to masters of vessels any advice or assistance which they may
require in case of shipwreck, or damage to vessel or cargo. It must
be remembered that Lloyd’s agents have no official authority
whatever over the master, and that they are the servants of Lloyd’s.
The master of the ship is responsible for both ship and cargo, and
need not employ Lloyd’s agent or follow his advice unless at his
own discretion.
In case of loss or damage from some peril insured against, the
* settlement of claims, if the ship is insured at Lloyd’s, will be much
facilitated if immediate notice is given to the nearest Lloyd’s agent.
Manifest.—A document containing a description of a ship, and
a list of her passengers (if any), cargo and stores.
COMPULSORY PILOTAGE
593
Mortgage of Ship.—A deed by which a ship is mortgaged or
pledged as security for money advanced. Only the owner can
mortgage a vessel
Pilot.—Legally the master is responsible to some extent for the
safe navigation of a ship when a pilot is on board, even if pilotage
is compulsory. The master may depose him if he proves incapable,
either from illness, drunkenness or any other cause.
The master is also responsible for seeing that the pilot's
instructions or orders are duly carried out.
The master is bound, if requested, to declare his vessel's draught
of water to the pilot. Penalty for refusal—a sum not exceeding
double the pilotage rates.
Penalty for fraudulently altering the marks denoting the draft—
a fine not exceeding £100.
If a master knowingly continues to employ an unqualified pilot
after a qualified pilot has offered his services, he is liable to a fine
of double the pilotage.
The same fine is payable if a master continues to navigate his
own vessel in a compulsory district after a qualified pilot has offered
his services ; that is, of course, if the master is not exempt from
pilotage, owing to his having obtained a pilotage certificate.
An owner or master shall not be answerable to any person for
damage or loss occasioned by the fault or incapacity of any qualified
pilot acting within a compulsory pilotage district, providing there
is no contributory fault on the part of the master or crew.
The pilot, however, is only liable up to the amount of his bond,
that is, £100, and the fee then being earned.
Portage Bill. —A bill, showing the wages earned, and the
amounts due to each member of the crew at the end of the voyage.
Primage. —A percentage beyond the freight paid by the
charterer.
Promissory Note.—A note promising unconditionally to pay
a certain fixed sum to a specified person at a determinable time.
Protest. —When the ship arrives at her port of destination, or if
she is obliged from any accident to put into an intermediate port,
the master should appear before a public notary, or the Consul if
594 NICHO-LLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
in a foreign port, and cause an entry or note of protest to be made,
and sign it himself.
The entering or noting a protest should be done as soon after
arrival as possible. It should be done within 48 hours, but if delayed,
a note giving the reason of the delay should be entered on the
protest.
The protest may afterwards be extended. This must be done
within six months of being noted. The extended protest should
contain a full narrative of the facts which form the subject of the
protest; the facts being taken from the log book, or supplied from
the recollections of the master, mate, or trustworthy seaman.
In most foreign countries the noting and extending of a protest
must be made within a specified time limit in order to make it
effective.
Protests are of great importance in connection with claims that
may arise under insurances, and also in the adjustment of averages
or claims on damaged cargo.
Copies of protests should be sent home to the owners.
Receiver of Wreck.—An officer appointed by the Board of
Trade. He is generally the chief officer of Customs at the nearest
port. His duty is to receive any wreck or wreckage which may be
brought to or washed up in his district. A list is issued by the
Board of Trade, setting out the different districts and receivers.
Register or Certificate of Registry.—When a vessel is
registered as a British ship, a certificate is issued to that effect, and
it contains particulars as to her name, port of registry, tonnage,
build, principal dimensions, and other points identifying the vessel;
also particulars as to her origin and name, and description of owner
or owners.
The master of a vessel must see that his name is endorsed on the
Register. This must be done in ordinary circumstances by the
chief officer of Customs at the Custom House at a home port, or
by the British Consul at a foreign port.
The certificate must only be used for the navigation of the
vessel; that is, for production at the Custom House when entering
or leaving port, and in other cases where it may be necessary.
Respondentia is a term, used to denote the fact of money
SHIPS AND CARGO SURVEY
595
being raised on the cargo as security. It differs from bottomry
in the fact that the cargo is pledged as security, and that, even
though the ship might be a total loss, if enough cargo was saved,
the bond would have to be repaid.
Salvage.—An allowance or compensation paid to those who,
by their efforts, have saved a vessel or goods from being lost.
Survey—Of Hatches.—The hatches should be surveyed before
opening, and should be opened in the presence of the surveyor.
A certificate should be obtained from him certifying to this fact;
also when the ship is full of cargo the certificate should state that on
lifting the hatches the vessel was found to be quite full. This may
be valuable in case of a claim for short delivery of cargo
Of Cargo.—Damaged cargo should be surveyed before being
disturbed so that the surveyor or surveyors may determine whether
it has been properly stowed and dunnaged, etc. If the damage
arises from insufficient dunnage or bad stowage the ship is liable for
the amount of damage. Particulars as to the amount and extent
of damage should be certified before the cargo leaves the vessel.
Of Vessels.—If a vessel receives material damage through
stress of weather, stranding, or other causes, a survey should be
held. The survey certificate should state fully the particulars of
damage, how caused, and recommendations as to what must be
done.
When repairs are completed a second survey should be held, and
a certificate of seaworthiness obtained before proceeding to sea.
For such surveys, wherever there are competent surveyors to
the Lloyd’s Register, it is desirable that they be called in with the
approval of Lloyd’s agents, and the co-operation and approval,
so far as possible, of any surveyor called in on behalf of underwriters
or special officer appointed by a Salvage Association on behalf of
underwriters should be obtained.
Surveyors.—At some ports there are licensed surveyors who
are specially employed on these duties. For surveying cargo, at
least one shipmaster or other person of nautical experience should
be employed. For survey of ship, two shipmasters or, in tfieir
absence, two other qualified persons.
- All surveyors must be disinterested parties.
596
NICHOLLS’S SEAMANSTTTP ANT) NAUTICAL KNOWLEDGE
The master should always bo present, and all parties whose
interests are concerned should bo notified when a survey is to be
held.
If damaged cargo is surveyed for the purpose of assessing the
amount of damage, two produce merchants acquainted with the
nature of the cargo (disinterested) should be employed.
CHAPTER XXI.
MISCELLANEOUS.
We have included in this chapter various drawings and subject
matter which might have been more appropriately given in other
parts of the book.
© © © ® ©
© ' © © ©
Fig I.—Some Built Section
Some Built Sections.—Eig. 1.
A —Two angles back to back, heels together.
B —Two angles back to back, heel and toe.
C —Two channel sections, back to back.
D —Four angles, heels together.
E —Bulb plate stiSened with two angles.
F —Girder web stiffened on both edges with angles.
Q —Girder same as F but further stiffened with a rider plate and
a foundation plate.
H —Girder web stiffened top and bottom edge by single angles.
I —A box girder formed by four plates connected at the inside
comers by angles.
See also page 448.
597
598
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Fig 2—Cellular Double Bottom.
Cellular Double Bottom.—Fig. 2 showing how the centre girder
is connected to the floors and to the inner and outer bottom.
A —A continuous fore and aft centre plate.
a x —Continuous fore and aft angles connecting centre plate
to inner bottom.
a 2 —Continuous fore and aft angles connecting centre plate to
the flat plate keel.
/ 3 —Short vertical angles connecting the floor plate to the centre
plate.
DETAIL OF DOUBLE BOTTOM
599
Fig. 3, showing the tank side arrangement of a C.D.B.
/ 4 —A vertical angle connecting the floor plate to the margin
plate 0.
h —A vertical angle connecting the tank side bracket H to the
maxgin plate G.
c —A continuous fore and aft angle connecting the lower edge
of the margin plate to the shell plating.
K —A hole in the floor to reduce the weight of material and to
provide access to the cellular spaces.
The upper figure shows in plan how the connection of the tank
side bracket to the margin plate may be strengthened by means
of a half-diamond plate.
C —The flange of the margin plate.
G —The half-diamond riveted to the flange and to the reverse
frame H on the upper edge of the bracket.
F —The stiffening angle along the top edge of the floor.
D —The inner bottom plating.
Figures 2 and 3 are enlargements from the drawing on page 440.
Stringer.—Figure 4 shows a plan and a sectional elevation of
part of a stringer.
S —A continuous stringer angle.
I —Intercostal plate slotted in way of frames F and F.
C —Chock angles fitted between the frames to connect the stringer
plate to the shell plating P.
L —A short lug piece to connect the continuous stringer angle 8
to the inner edge of the bulb frame.
600
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Web Frame (see also page 443).—Figure 6 (i), (ii), (iii) are
three views of a web frame at its juncture with a stringer.
(i) This is a view from aft.
c —The frame angle riveted to shell plating.
a —The web stiffened on its inner edge by angles 6.
k —A diamond plate as shown in (ii).
h —Short angles connecting the web to the stringer plate.
g —Short chock angle fitted between the frames to connect
stringer to shell plating.
(ii) A side view.
k —Diamond plate connecting the continuous vertical angles
b on the edge of the web a and the angles e on the edge of
the stringer plate d.
(iii) A plan view of the stringer,
c—The frame angle.
g —Chock angle.
dr —Stringer plate notched in way of frames to fit against shell
plating.
A WATERTIGHT FLAT
601
h —Angles connecting web to stringer plate.
/—Angle on under side of stringer plate connecting it to the
frames.
e—Stiffening angles on inner edge of stringer.
h —The diamond plate.
Watertight Flat (see also page 452). Fig. 6—
W (H>
Fig. 6.—Watertight Flat.
(i) The frame and reverse frame are cut to allow the dock flat plating
to fit against the shell plating B, to which it is connected by the
continuous fore and aft angle a,
di —Bracket riveted to the frame.
d 2 —Angle connecting bracket to deck plating.
E —Beam, and e ly the beam knee.
(ii) A view in plan, the index lettering being the same as above.
v
602 mOHOLLS’s SEAMANSHIP AND NAUTICAL KNOWLEDGE
Hatch Coaming (see also page 459). Fig. 7—
(i) A —Coaming plating.
a \—Angle connecting coaming to deck plating.
d 2 —Deck beam.
a 2 —Vertical angles inside coaming to form a slot to receive the
end of the portable athwartship beam, they also stiffen
the plating.
a t —A half round section on upper edge of coaming.
It will be noticed that the end of the half beams are connected
to the lower edge of the coaming in conformity with modern practice.
Formerly, however, the ends of half beams were connected to an
independent fore and aft vertical plate called a “carling” which
extended the length of the hatchway. A plate similar to a hatch
carling may be fitted to secure the inner end of a half beam when cut
in the way of a mast coaming. These fore and aft vertical plates are
then called the mast “partners.”
Fig. 8.
HATCH COaMINGS
603
(ii) This is a hatch end.
B —The athwartship coaming.
6 2 —Carrier for the end of the portable fore and aft beam K to
rest in. Length of bearing 3 inches.
61 —Angle connecting coaming to deck plating.
/—Wood hatch covers at least 2\ inches thick.
—Ledge 2 -| inches broad for hatch covers to rest on.
g —Tarpaulin.
a 6 —Cleats 2 feet apart and 2 £ inches wide.
e—Flat iron bar to grip the tarpaulin when wedged up tight at
the cleats.
Deep Tank Top.—Fig. 9 illustrates a method of making the
portable top of a tank watertight or oiltight. Note the washer of
soft material, rope or rubber usually, between the top edge of the
Washer
coaming and the under side of the steel cover, and how close contact
is secured by means of numerous bolts and nuts round the eoaming.
Wing nuts are usually fitted to the deck hatches of oil tankers*
Note also the hinged bolts which fit into slots in the edge of the
cover.
604 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
jjig. 16 .—A hatch coaming as sometimes fitted in small vessels
A —Wooden hatch cover resting on ledge B and on wood fore-
and-after < 7 , which in turn rests on the portable hatch beam D.
E —Stiffening angles on lower and upper edge of hatch beam.
F —Angle connecting coaming to deck plating.
G —Stanchion connected to coaming and to deck plating by lug
pieces to give support to coaming.
H —Bulwark stanchion.
J —Large bracket to contribute compensation for loss of strength
due to cutting beams in way of wide hatchway.
Strifm Box.—Fig. 11 shows a strum box enclosing a bilge suction
BILGE PUMPS
605
v*j
to protect the end of the pipe. At least one side of theVbox is
removable for cleaning-out purposes ; this drawing shows thc^fOur*
sides as a sliding fit into the framework of the box. Suction ends
in hold spaces are enclosed in strum boxes having perforations not
more than three-eighths inch in diameter, whose combined area is
not less than twice that of the suction pipe.
It is very important to make sure that the strum boxes are cleaned
out and the suction ends clear before commencing to load cargo.
Downton Pump (Fig. 12).—This hand pump is operated by
means of a flywheel and a handle which turns a crank inside the
housing. The crank lifts and lowers the piston, or plunger, and an
inspection of the sectional drawing will indicate how the suction
and delivery valves open and close turn about as the piston goes up
and down.
The tail pipe is fitted with a gooseneck to fit on to various bilge
suction pipes, or to a sea connection.
This pump may be utilised to pump out any compartment
fitted with connections, and the delivery may be directed on deck
as indicated by the hose coupling, or discharged overboard.
Freeing Ports.—The openings in the bulwarks to clear the
decks of water when heavy seas are shipped may be left as openings
with safety bars across them spaced not more than 9 inches apart,
or they may be fitted with a hinged door which opens and closes
automatically.
606
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Fig. 13 illustrates one type of closing port. It is hinged about
one-third from the top edge. The end elevation shows that when
the vessel rolls the water runs to leeward, pushes outwards against
the port, which it opens, and flows overboard.
The area of freeing ports depends upon the area of the bulwarks
according to the following scale :—
Well deck in feet 25 ; area of openings in sq. ft. 9
» 99 ^ 9 99 99 »> 11
J) 99 ^ 9 99 99 99 13
In well decks above 65 feet in length the area of freeing port
is 1 square foot for every 5 feet of bulwark, thus, 80 feet bulwark
would require 16 square feet of openings.
Ventilator.—Fig. 14 illustrates a common type of ventilator,
It is trimmed as required by turning the cowl A on its coaming B ,
which is secured to the deck by a watertight collar C. An inner
tube of smaller diameter than the coaming leads down to the lower
hold. The current of air passes down the inner tube of the ventilator
to the lower hold, but some of the air is diverted into the ’tween
deck through the annular space between the tube and the coaming.
Two or more ventilators are fitted to each hold in tramp steamers,
one, the lee one usually, being trimmed mouth to wind and the other
one back to wind, thus forming a downtake and an uptake to create
a continuous current of air throughout the hold. Some cargoes give
off gases lighter than air, coal for example, and in such cases surface
VENTILATION OP HOLDS
607
ventilation is needed, and the ventilators should be turned backs to
the wind. Coal is leas likely to ignite if starved of air. See page 392.
When ted weather approaches, especially at night, and the
vessel is lik Ay to ship heavy water, it may be necessary to turn all
ventilators oack to wind and perhaps to put a canvas cover over the
Lower t-joi-P
Fig. 14.—Ventilator.
cowl if they are not high enough to prevent spray and sea water
getting into them. During heavy weather at night time it is desir¬
able to inspect occasionally the ventilators and hatch covers to
ensure that everything on deck, fixed or movable, fittings or cargo»
is secure, and that deck openings are properly covered and water¬
tight.
FROZEN MEAT.
The following photographs illustrate a method of slinging carcases
of frozen meat. The carcases are stowed in the canvas sling head
and tail alternately. About 80 carcases can be lifted in one sling
without risk of damage and with a minimum opening of the
608
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Fig 15.—The set made up in tiers head and tail alternately.
Fig. 16.—View of sling when being lifted.
RELIEVING TACKLES
609
hatchways. The carcases are stowed in the hold tore and aft, bottom
tier on their backs and belly to belly afterwards. The hold
temperature during the passage is kept as near as possible to 15°
Fahr. See also page 410.
Fig 17.—An end view of sling.
RELIEVING TACKLE,
When there is considerable play on the rudder due to worn
pintles and the back kick on the steering gear is severe, especially
during heavy weather, it is desirable to fit an arrangement to reduce
the wear due to constant jolting. The kick of the rudder causes a
sudden jerk on the steering gear, and in small vessels steered by
hand gear the back-lash may be heavy enough to throw an unsus¬
pecting helmsman over the wheel if he held on to it.
Fig. 18.
610
Nicholas’s seamanship and nautical knowledge
Fig. 18 shows a simple relieving tackle for small vessels, but in
large vessels this is quite inadequate, and many are fitted with a
friction brake, one of the simplest and most effective being the
“ Dunstos ” Rudder Brake as illustrated.
Fig 19
Fig. 19 gives a general view of the arrangement. Two brackets
are fitted on deck, one on each side of the quadrant, and a free wheel
rotating on a vertical axis, the foundation of which is bolted to the
middle of the quadrant near to its circumference. The end of a
wire is shackled to one bracket, a turn of the wire is taken round the
pulley, and the other end of the wire is set up tight to the other
bracket by means of a tightening screw.
Frictional resistance to back-kick is obtained as follows (see
Figs. 19 and 20):—
A base plate A with a central axis having a recess all round bs
securely bolted to the quadrant, the circular recess in base is fitted
with hardwood in segments B.
A double grooved sheave G is fitted, free to revolve on the axis
of the base plate, the bottom of the sheave rests upon the wood B,
ROPE AND ITS PRESERVATION
611
and a loose plate or cover D rests on top of the sheave, with wood
ring E between them. This cover is prevented from turning by pins.
A hand wheel engages with a screw operating a spring ; by turn¬
ing this wheel the grooved pulley is compressed against the wood
and retarded or released at will
As the rudder moves, the sheave revolves, and by simply turning
the hand wheel any desired resistance can be applied, this depending
on the state of the weather ; you simply screw down httle by little,
till the gear stops kicking, and as the weather moderates ease up to
suit. In fine weather the sheave runs freewheel, or the wire may be
taken off. In the event of a steering cham carrying away, the
quadrant may be held in position by screwing the brake hard down
until the hand gear is connected or the chain repaired or replaced.
ROPE.
Rope is made of manilla, sisal, hemp or coir fibres twisted into
yarns, the yarns into strands, and three strands, sometimes four,
are laid up together to form a rope.
Manilla is glossy, smooth, and pliable and good.
Sisal is stiff, harsh, short fibre and not so good. A proportion
of both manilla and sisal is frequently worked into one rope.
Hemp is the best fibre, of great strength and durability, flexible
when wet and wears to the last rope yam.
Boltrope is tarred hemp used for sewing round sails to strengthen
the head, foot and leech, also for lanyard rigging.
Coir is made from cocoanut husk fibre ; it is reddish in colour,
light in weight, about half the strength of manilla, stretches before
parting, and is often used for mooring alongside a wharf where a
ground swell is making a ship range heavily. Coir does not absorb
water, is buoyant, and therefore handy for harbour work when
running hauling lines by boat across a dock.
Hawsers.—Any rope over 5 inches may be ca3ed a warp or
hawser.
Small Stuff.—Marline is two yarns of tarred hemp spun to¬
gether ; housline is three yarns, and both are used for worming and
serving ropes and for seizings, Spunyarn is softer, made of two or
three coarse yarns and is used for serving and general work on
board ship.
612
NICHOLLS’s SKAMANS1I1J? AND NAUTICAL KNOWLEDOB
Fig 21.
Protection of Rope.—Some ropes have to be protected from
chafing. The rope is first wormed by filling in the lay with small
stuff to make it more nearly round, it is then parcelled with strips
of tarred canvas about 2 inches broad and finally it is served, that
is, spunyam is. wound tightly round the parcelling with a serving
mallet or board, all according to the rhyme, “ Worm and parcel
with the lay, turn and serve the other way.”
Preservation of Rope.—Taut ropes when dry should be slacked
off when wet. They should not be coiled away when wet or damp,
but coiled down loosely on gratings or flaked over a boom to ensure
them being well aired and dried before storing them away.' Rope
lockers should have sparred shelving and all ropes should be brought
on deck occasionally to be sunned and aired, as particles of salt
remaining in the rope draw dampness, which produces dry rot.
Hauling lines stored on deck should be covered over, especially
those aft, to protect them from grit and cinders from the funnel.
Ratline is small rope made of tarred hemp, and its size is
referred to as 15, 18 or 21 thread ratline as the case may be. Its
original purpose was to form a rope ladder across the shrouds by
which to climb the rigging, but wooden battens or iron rods are now
more commonly used. Many steamships have an iron ladder built
on the mast, and big ships may have the ladder leading to the
crow’s nest inside the mast.
To rattle down you begin at the bottom and rattle up, but first
the shrouds are set up equally taught, widely spaced battens are
seized across them to keep the shrouds rigid, and the ratline, direct
from the coil, is clove-hitched loosely round each shroud from left
to right except the forward and after shrouds, to which it is seized.
The eyesplice on the end of the ratline is seized to the right .
PARALLELOGRAM OF FORGES
613
hand shroud, then tightened up from right to left, and finally the
other end is seized to the left hand shroud.
The next higher ratline is done in the same way, and they are
spaced 15 inches apart.
The Lansley Stress Finder comprises a set of movable metal scale
bars which can be set to solve the various parallelograms of forces
in connection with derrick work without calculation.
A B represents the mast which
is adjustable up or down to
suit the height of span above
the gooseneck.
B D the span or topping lift.
G D the derrick.
B E shows the stress on the
block at B.
D F gives the thrust on the
derrick.
G R is the stress on the heel
block at C.
The other arms show the various
component stresses involved.
• The makers are Messrs. Kelvin,
Bottomley and Baird, Glasgow.
PAINT.
^ (See also page 480.)
Preparation of Surfaces.—All loose paint, rust, dirt and grease
should be removed from ironwork and the metal thoroughly dried
before applying the paint. The preparation of the material is of
groat importance to enable the paint to secure a firm grip on. the
material by penetrating into the surface pores. Paint won’t cling
to a dirty face.
Paint is usually sent on board ready mixed and only requires
stirring, and perhaps thinning with linseed oil and turpentine before
application. Red lead, however, is generally in powder, and if mixed
solely with oil the heavy pigment settles and forms a hard, solid
mass on the bottom of the container. This tendency is reduced
by first mixing the powder with water to form a stiff paste, then,
614 mCHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
by adding linseed oil gradually the water is displaced which oozes
to the surface and can be poured off. This seems to prevent the
particles from uniting so firmly as to form a solid mass.
Covering Properties.—This vanes considerably according to
the consistency of the paint, the roughness of the surface, and the
temperature. A fair average is 50 square yards per gallon for good
paint.
Bituminous Compositions.—This composition is largely com¬
posed of pitch, and other ingredients as rosin, cement, slaked lime
and petroleum. It is made up as a solution, an enamel and a cement.
Bituminous paint solutions are applied with a brush; enamel is
applied hot and is poured or spread over the surface ; bituminous
cement is also applied hot on horizontal surfaces. The cement is
used as a protective coating in ballast tanks, chain lockers, bunkers,
engine and boiler foundations, and as a damp proof coating where
required.
Antifouling compositions referred to on page 481 are poisons
manufactured usually from copper, mercury, arsenic or other mineral
poisons, the object of the composition being to dissolve slowly on
contact with the sea water so as to form an antiseptic film or surface
to destroy the marine growth before it has time to develop.
Marine Growths.—The innumerable animalculae which live
in the sea are known as plankton, and this microscopic animal and
plant life is usually more abundant in coastal waters than in mid¬
ocean. The plant life forms weed or “ grass ” fouling on the sub¬
merged shell of the ship, but as this green growth requires light its
location is confined to a strip along the waterline.
The Barnacle which attaches itself to the skin surface starts
off as a microscopic egg floating about in the sea On reaching the
larval stage it swims freely, develops eyes, and appendages bearing
suckers furnished with glands which secrete an adhesive cement
thus enabling it to attach itself to hard underwater surfaces. The
barnacle having fixed itself to the plating of a ship grows gradually
into adult form and cements its back to the plating and feeds on
any microscopic organism that comes within range of its legs,
which are fringed with fine hairs to scoop into its mouth the organ¬
isms.
The Toredo Worm bores its way into timber. It is a mollusc
floating in the sea which, on finding a suitable medium, enters the
UftYDOCKING AND PAINTING
615
wood by cutting a small hole the size of a pinhead. The mollusc
then bores its way into the wood, develops in length to a few inches,
and lines its burrow with a shelly substance which it secretes.
The wood in time soon becomes riddled with holes and crumbles
away.
DR YD O CKING.
(See also page 339.)
A Graving Dock is one with a cofferdam gate. The gate is
opened, the ship floated in, the gate is then closed, the water pumped
out, and the ship is left resting on keel blocks and steadied upright
by side shores and bilge shores.
A Floating Dock has no ends, but has a double bottom and
high side tanks. The tanks are flooded with water until the bottom
of the structure sinks below the level of the vessel’s keel. The vessel
is floated in, and steadied into position, the tanks are then pumped
out, and the dock rises under the vessel and lifts her up.
A Slipway is a cradle on an inclined railway track extending
into the water. The cradle is run down the trackway under the
vessel, which she approaches bow on, rides on the cradle, and is
hauled up the slip by means of winches and wire purchases.
In Dry Dock.—Examine all underwater valves, sea cocks,
injection and ejection pipes, and particularly rudder pintles, gudgeons
and bearings for clearances and renewals. Take a note of any in¬
dented plates if they are*not to be renewed, remembering that they
are indicated by letters A, B, C , etc., from the keel upwards and
numbered 1, 2, 3, etc., from aft forward. Propeller nut and boss
should be examined for corrosion, and zinc plates, if any, renewed.
Look for evidence of leakage at riveted joints in way of peak tanks,
and bulkheads due to panting, and encircle the rivets with a
chalk mark as they will either have to be caulked or renewed.
When any rivets have been knocked out for the purpose of
draining water ballast tanks it will obviously be necessary to make
sure that the holes have been reriveted.
When repairs and painting have been completed notify the chief
engineer when water is to be run into the dock, so that he may ensure
that all underwater openings will be closed.
616
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
A Sailing Ship (Fig. 23).—A head-on view showing the square
sails on the foremast. The names, given in their order upwards
are :—Foresail, lower topsail, upper topsail, topgallant sail, royal.
Note the bunthnes for hauling the foot of the sail up to the yard.
They are seen girting across the belly of each sail.
Fig. t>X
Fig. 24.—A broadside view. The square sails are named the
same on each mast as on the foremast, with the exception of the
lower sail on the mizzen, which is called the crojack. The
and crojack in the photograph are furled. The fore, main and
A SAILING SHIP
617
royals have just been unfurled, to be ready for setting by hauling out
their clews by means of their sheets to the yardarms of their re¬
spective topgallant yards, and then hoisting the yards to the royal
masthead by the halliards.
T*i
Fig. 24.
Barque Carradale launched 1SS9, scrapped 1925.
The fore and aft sails that are set, starting aft, are named:—
Spanker, jigger staysail, mizzen topmast staysail, and on the bow¬
sprit there are the fore topmast staysail, inner jib and outer jib.
618
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Spare parts for rod and chain steering gear; by agreements
between the Ministry of Shipping and the Shipping
Federation.
Ships under 12 knots:—
1 complete spring buffer and 1 spare spring. 2 tested chains
equal to the longest length in the gear or, alternatively,
1 spare set of all the lengths on one side.
2 bottle screws; 2 sheave pins; 4 shackles; 4 connecting links;
4 rod pins.
Ships over 12 knots and all Home Trade ships and Coasting
vessels.
1 tested chain equal to the longest length in the gear.
1 spring buffer; 1 bottle screw.
4 shackles; 4 connecting links * 4 rod pins; 2 sheave pins.
CHAPTER XXII.
INTERNATIONAL CODE OF SIGNALS.
CHAPTER XXII.
THE INTERNATIONAL CODE OF SIGNALS.
EXTRACT FROM THE REGULATIONS.
There are seven editions of the International Code of Signals translated
into seven languages, English, French, German, Italian, Japanese,
Spanish, Norwegian, and from January 1, 1934, the new Code will
supersede the former Code. The book consists of two volumes, Volume
I. is devoted to Visual Signals by Flags, Morse and Semaphore; Volume
II. to Radio Signalling.
Although the majority of radio signals to and from ships are, and
doubtless will continue to be, transmitted in plain language, and
between foreigners often in the English language, it was considered
that an International Code for use by radio was needed to make full use
of the exceptional means of communication with which radio provides
them, and because tlier^ are in many parts of the world those who are not
well conversant with any other language than their own. A further
advantage of the new Code lies in the fact that nautical and technical
expressions have been adjusted in the seven editorial languages so that
the use of the Code should facilitate the exchange of correct and concise
information between people not speaking the same language.
The Code is primarily intended for use by ships and aircraft; and, via
shore radio stations, between ships or aircraft and authorities ashore,,
such as harbour authorities, quarantine authorities, agents, etc.
621
622
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
The one, two, three and four-letter flag hoists are arranged in alpha¬
betical order, as also are the chief words of their corresponding phrases
and sentences, so that coding and decoding can usually be made at one
opening of the book. The four-flag signal letters of ships are given in
a separate book entitled The Mercantile Navy List and also in another
book called Signal Letters of British Ships. The top flag of the hoist
indicates the nationality of the vessel; for example, the top letter of
the names of British ships is flag “(?” or flag “ M.”
THE CODE FLAGS.
The set of Code flags consists of 26 alphabetical flags (one for each
letter of the alphabet), 10 numeral pendants (one for each unit 1, 2, 3, 4,
5, 6, 7, 8, 9, 0), 3 substitutes and the Code pendant—40 flags in all.
Five new flags have been introduced, C, Z), E , F and G , to replace
those letters of the former Code which were represented by pendants;
those pendants, without alteration, now indicate respectively the
numerals 1, 2, 3, 4 and 5 of the new Code with the addition of five
new pendants to make up 6, 7, 8, 9 and 0, the decimal point being
indicated by the Code pendant. A pendant now represents a numeral
only and is referred to as No. 1 numeral, No. 2 numeral, etc., and a
flag represents a letter of the alphabet and is referred to as letter “A”
or letter etc.
Single-letter signals, one for each flag, are either very urgent or
of very common use. A second series of single-letter hoists are towing
signals. See page 636.
Two-letter hoists are mostly distress, urgent and important signals
with the addition of a few general signals of common use. See examples,
pages 636 and 637.
Three-letter signals are general in character and are used for words,
phrases and sentences. See examples, page 637.
Four-letter hoists commencing with the letter “A” are geographical'
signals, and four-letter hoists commencing with letter G are the signal
letters of British ships.
USE OF THE SUBSTITUTES,
The substitutes are intended to indicate a repeat of the same flag,
or pendant, in a hoist, so that double or even treble letters or figures
may be conveyed in the same hoist by one set of flags only.
THE INTERNATIONAL CODE OF SIGNALS
623
GEOGRAPHICAL HOISTS
Example .—Letters A A AS mean Aberdeen, Scotland, and would
be hoisted.—
1st substitute means repeat the top letter of
the hoist, namely A, and 2nd substitute
means repeat the second letter of the hoist,
which, in this case, is also A , thus making
the hoist A A A S,
Note ,—It might be a useful lesson in flag identification if the student
were to put m the colourings of the respective flags in the several
illustrations given here.
Example ,—Letters A BU V mean Blacksod Bay, Ireland, and
would be hoisted.
A
B
tE
u
3rd sub
3rd substitute means repeat the third letter
of the hoist, which in this case is Z7, thus
making the signal A B U U.
These are two examples of geographical signals intimating th#
names of places and all such signals are four-flag hoists beginning with
flag A . The hoists and the names of the places are arranged in the
Code book in strictly alphabetical order, in parallel columns, the name
of the place and Its hoist being alongside of each other, so that code
and decode are made simultaneously at the same opening of the book.
624
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
NUMERAL HOISTS
Example .—Numeral signals are made without reference to the Code
book. If it were required to signal the number 2266, then the hoist
would appear—
No. 2 pend’t
1st sub
No. 6 pend’t
3rd sub
1st substitute means repeat the top
numeral of the hoist, which is 2, and 3rd
substitute means repeat the third num¬
eral of the hoist, which is 6, thus mak¬
ing the signal 2266.
Example .—Signal the number 5555.
1st substitute means repeat the top
numeral.
2nd substitute means repeat the second
numeral ju»t as if No. 5 pendant had
been hoisted instead of 1st substitute.
3rd substitute means repeat the third
numeral from the top, just as if No. 5
pendant had been hoisted instead of 2nd
substitute, thus making the signal 5555.
This is the extreme limit to which the use of the substitutes can go,
and no substitute can be used more than once in the same group.
Example .—To signal the fishing vessel registration number Y H 344,
we would hoist—
The 2nd substitute, in this sense, means
repeat the second numeral, viz., No. 4
pendant, because the 2nd substitute is in
the numeral part of the hoist, thus com¬
pleting the signal YarmoutH 344.
THE INTERNATIONAL CODE OF SIGNALS
625
SINGLE-LETTER HOISTS.
Single-letter hoists relate to important phrases which are in common
use.
Single-letter Signals.
Only those maiTced with an asterisk should be used by flashing
A I am undergoing a speed trial.
B I am taking in or discharging explosives.
G Yes (affirmative).
D Keep clear of me—I am manoeuvring with difficulty.
E I am directing my course to starboard.
*j F I am disabled. Communicate with me.
G I require a pilot.
H I have a pilot on board.
I I am directing my course to port.
J I am going to send a message by semaphore.
You should stop your vessel instantly.
*Z You should stop. I have something important to communicate.
M I have a doctor on board.
N No (negative).
*0 Man overboard.
*P In harbour (Blue Peter)—All persons are to repair on board as
the vessel is about to proceed to sea. (Note: To be hoisted
at the foremast head.)
At Sea —Your lights are out, or burning badly.
Q My vessel is healthy and I request free pratique.
*R The way is off my ship; you may feel your way past me.
S My engines are going full speed astern.
T Do not pass ahead of me.
* U You are standing into danger.
*F I require assistance.
*W I require medical assistance.
X Stop carrying out your intentions and watch for my signals.
Y lam carrying mails.
* Z To be used to address or call shore stations.
026 NICHOLLS'S SEAMANSHIP ANr> NAUTICAL KNOWLEDGE
Letters P, T and X have also special significance when signalling
latitudes, longitudes, times, courses and bearings in degrees, all of which
are made by means of the numeral pendants without reference to the
Code book, as per following examples:—
LATITUDE AND LONGITUDE
Letter P refers to position and is the top letter of the numeral
hoist when signalling latitude and longitude.
P
3
6
2
4
N
Means Lafc 86° 24' N., a six-flag hoist.
P
7
0
2nd sub
5
E *
Means Long. 70° 05' E., a six-flag hoist,
_ When the longitude is 100° or more the first figure need not be
hoisted unless to prevent misunderstanding as to whfther the degrees
THE INTERNATIONAL CODE OP SIGNALS
627
are under or over the 100, thus Long. 176° 40' W. may appear as hoists
(i) or (ii).
(i.) (n.;
P
l
7
6
4
0
W
Nor need the letters N or S (North or South) in latitude signals, or
the letters E or W (East or West) in longitude signals be hoisted unless
to avoid confusion should the latitude be near the equator, or the
longitude close to the Greenwich or to the 180th meridians.
TIME SIGNALS.
The letter T refers to time and is the top letter of the numeral
hoist when signalling hours and minutes. Time is expressed in four-
figure notation, the first two figures of the group indicate the hours, the
second two figures indicate the minutes, thus:
T
1
8
3
5
Greenwich mean time for chronometer comparison may be signalled
in the same way, the first two numerals indicating the hour and the
623
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
second two numerals an approaching exact minute of time about to
occur. The “exact” time will be that moment at which the signal is
sharply hauled down.
An exact time may be signalled in the Morse code by first sending
the time in advance and following the time signal with a long flash
(dash) of about 5 seconds duration, the end of the flash (dash) being the
exact time indicated by the four numerals.
COURSES AND BEARINGS.
Letter X refers to courses and bearings. It is the top letter of the
numeral hoist when signalling direction expressed in degrees from 000°
to 359°, the direction to be read as true courses or true bearings unless
expressly stated otherwise.
The position of a place may be signalled by means of its bearing
and distance from a stated place, the procedure to be always in the
order, Bearing—Distance-Place.
Example —“185°, 20 miles from the Lizard” would appear in three
hoists.
X
1
8
5
(ii.)
(iii.)
A
J
K
#
E
i
185°
20 miles. The Lizard
England
POINTS OP THE COMPASS.
Each of the 32 points of the compass is allocated a group of three
letters in the Signal Code, thus J V O means N.N.E.; N T L means
S.E., etc.
THE INTERNATIONAL CODE OP SIGNALS
RELATIVE BEARINGS.
629
Bow, beam and quarter bearings for each point and for every 10°
round the horizon are also given in the Code.
Examples —
AAA
means
1 point on the port bow.
A AH
on the port beam.
ABQ
99
3 points abaft the starboard beam.
A AW
99
80° to port.
AOG
»
120° to starboard.
EBF
»
right ahead.
RGA
99
right astern.
ALPHABETICAL SPELLING SIGNALS.
By this method each flag represents the actual letter of the alphabet
corresponding to its name. Thus flag A stands for letter a, flag B for
ietter 6, and so on, and this being understood, any name or word can be
spelt by the flags themselves without referring to the Signal Book.
When spelling by this method the three following signals must be used
in order to indicate that the flags are to be given their alphabetical
meaning for the purpose of spelling words:—
Signal Meaning
Code Flag over E - Alphabetical Signal No. I indicating that the
flags hoisted after it, until alphabetical signal
No. 3 is made, do not represent the signals in
the Code, but are to be understood as having
their alphabetical meanings, and express
individual letters of the alphabet which are
to form words.
F Alphabetical signal No. 2 indicates the end of a
word or dot between initials
0 - Alphabetical signal No. 3 indicates that the .
. alphabetical signals are ended.
630 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Example .—To spell William John Perry, the procedure would
be as follows:
(i.) (ii.) (iii.) (iv.) (v.) (vi.) (vii.) (viii).
MEANING
The letters which follow are alphabetical:
William
End of word
John
End of word
Perry
End of spelling.
William may be signalled as one group by hoisting the flagB
“W I L 3rd substitute 2nd substitute A M’\
Bach hoist is kept flying until the receiving ship acknowledges it by
hoisting her answering pendant
HOIST
(i.) CodeE,
(ii.) WILL)
(iii.) 1AM J
(iv.) Code F,
(v.) JOHN
(vi.) CodeF,
(vii.) PEMY
(viii.) Code G,
SfOTES
831
634
THE INTERNATIONAL CODE OP SIGNALS
635
THE SIGNAL BOOH.
The following excerpts from the Signal Book are intended to
convey an idea of the layout of the Book and to provide examples
for exercise as given in the Catechism, page 660.
SPEED.
V Z You should increase your speed to speed indicated
WO You should proceed at your utmost speed
W D You should reduce your speed to speed indicated
W F Are you proceeding at full speed
W F What is your present speed
TOWING SIGNALS.
To be used only when towing and being towed.
These signals are to be made—
By Day.—A single flag, which may be exhibited by being held in
the hand or by hoisting at the stay or fore shrouds, or at the
gaff, according to circumstances.
By Night. —By flashing , care being taken not to confuse other
ships.
Towing Signals.
By the Ship Towing.
A Is the towing hawser fast? A
B Is all ready for towing? B
C Yes (or affirmative) C
B Shorten in the towing hawser JD
E I am altering my course to starboard E
F Pay out the towing hawser F
G Cast off the towing hawser G
H I must cast off the towing hawser H
1 I am altering my course to port I
J The towing hawser has parted J
K Shall I continue the present course ? K
E I am stopping my engines L
M I am keeping away before the sea M
N No (or negative) N
0 Man overboard 0
P I must get shelter or anchor as soon P
as possible
Q Shall we anchor at once? Q
R I will go slower R
S My engines are going astern S
T I am increasing speed T
U You are standing mto danger U
V Set sails V
W I am paying out the towing hawser W
X Get spare towing hawser ready X
Y I cannot carry out your order Y
Z I am commencing to tow Z
By the Ship Towed.
Towing hawser is fast
All is ready for towing
Yes (or affirmative)
Shorten m the towing hawser
Steer to starboard
Pay out the towing hawser
Cast off the towing hawser
I must cast off the towing hawse
Steer to port
The towing hawser has parted
Continue the present course
Stop your engines at once
Keep away before the sea
No (or negative)
Man overboard
Bring me to shelter or to an anchor
as soon as possible
I wish to anchor at once
Go slower'
Go astern
Increase speed
You are standing into danger
I will set sails
I am paying out the towing
hawser
Spare towing hawser is ready
I cannot carry out your order
Commence towing
Note .—The Towing Signals C, E, J, N, 0, 5, and U when made by the
ship towing have the same meanings as those of the single-letter signals on
page 625
TWO-LETTER SIGNALS.
♦
Tow—Towing,
I am disabled. Will you tow me in or into place indicated L J
X S I am towing a float
XT I am towing a target
XU I cannot take yon, or vessel indicated, in tow
I have parted towing hawser, can yon assist me * * I* U
XV I, or vessel indicated, require,s towing
X W I require a boat or tug to tow me to berth
X Y Can yoh take me in tow
X Z Shall I take you in tow
THE INTERNATIONAL CODE OF SIGNALS
637
Weather.
Y T Bad weather is expected from direction indicated
Y U Gale is expected from the direction indicated
Y V Heavy gale coming: take necessary precautions
Cyclone, hurricane, typhoon is approaching. You should put
to sea at once. G Y
Thick fog is coming on.- - - HU
Y W Weather report is not available
You should prepare for a cyclone, hurricane, typhoon - IK
Y X You should wait until the weather moderates
Y Z Is bad weather expected
Z A What is the barometer doing
Z B What is the weather forecast for tcT-day
Z G What is the weather forecast for to-morrow
GENERAL CODE.
CEO Boat,s
(Not to be used in the sense of ship)
G G L You should send your boat to pass towing hawser
G GM You should veer a boat astern
G G N Your boat, s should keep to leeward until picked up
Your boat, s should keep to windward until .hoisted - F Z
G GO Are there any boats in sight
N LG Signal, s
Signalling- Am, 1s, Are
N LH Signalled- Has, Have,ing »
N M J l wish to signal to vessels number indicated if necessary on
bearing indicated from me
I wish to signal to you. Will you come within easy signal
distance .- - - * U Z
NMK The signals are not intended for you
N M L Signal exercise finished
Signal is not understood though flags are distinguished - V B
You are flashing your signal too quickly - - • - GHF
Station
0 B B Stationed at (Located at)
OBG Keep,s station, on
Keeping station, on - Am, Is , Are
0 B D Kent station, on- Has, Havering
B38 NICHOLLS’S SEAMAN SHI JP AND NAUTICAL KNOWLEDGE
0 B E Take,s station
Taking station- Am, Is, Are
0 B F Taken, Took, station- Has, Have,in#
Towing Hawser,s .. ' RM X
P F L I cannot send towing hawser
I have made chain cable fast to towing hawser C Q C
I have parted towing hawser; can you assist me - - DU
P F M Towing hawser has parted
P F N Towing hawser is damaged
P F O Towing hawser is fast
P F P You should ease up dead slow, I want to secure towing hawser
P F Q You should have a towing hawser ready
You should shorten the towing hawser - •> - NHL
You should veer the towing hawser - - • • P T H
P F R Are towing hawsers fast
P F S CAST,S off TOWING HAWSER,S
Casting off towing hawser’s- Am, Is, Are
P F T You should cast off the towing hawser
P F V Cast off towing hawser,s- Has, Have,ing
P R B International Code of Signals
„GEOGRAPHICAL SECTION.
A ACC
Adderley Hd. - ...
- New Zealand
AACD
Adelaide -------
- S. t Australia
A ACE
Adelaide, Port ------
- S. Australia
AACF
Aden - -- -- -- -
- Arabia
AACG
Aden, G. of ......
RELATIVE BEARINGS.
* Arabian Sec.
AAA
1 point on the port bow
AAB
2 points on the port bow
AAC
3 points on the port bow
AAD
4 points on the port bow
AAE
3 points before the port beam
AAK
3 points abaft the port beam
AAL
on the port quarter
AAM
3 points on the port quarter
A AN
2 points on the port quarter
A AO
1 point on the port quarter
THE INTERNATIONAL CODE Of SIGNALS
639
A A P 10° to port
A A Q 20° to port
AAR 30° to port
A AS 40° to port
A AT 50° to port
A BY 10° to starboard
A BW 20° to starboard
A B X 30° to starboard
A BY 40° to starboard
A B Z 50° to starboard
FLAGS TO 8E FLOWN BY BRITISH MERCHANT SHIPS.
Section 74 of the Merchant Shipping Act, 1894, provides as follows:—
1. A ship belonging to a British subject shall hoist the proper
national colours—
(a) On a signal being made to her by one of His Majesty’s ships
(including any vessel under the command of an officer of His
Majesty’s Navy on full pay); and
(b) On entering or leaving any foreign port; and
(c) If of 50 tons gross tonnage or upwards, on entering or leaving
any British port.
2. If default is made on board any such ship in complying with this
section the master of the ship shall for each offence be liable to
a fine not exceeding £100.
3. This section shall not apply to a fishing boat duly entered in the
fis ing boat register, and lettered and numbered as required by
the fourth part of this Act
640
NICHOLAS'S SEAMANSHIP aWD NAUTICAL KNOWLEDGE
SEMAPHORE.
Procedure.
1. The person intending to semaphore hoists semaphore flag («T;
where most convenient and where best seen.
2. The other ship will then hoist the answering pendant at the dip
to indicate that flag (J) has been observed, and when she is ready to
read the message the answering pendant will be hoisted close up.
3. The sender keeps semaphore flag (J) flying while the message is
being made and hauls it down on completion of the message.
4. All messages are semaphored in plain language and numbers
occurring in a message are spelt out in words.
5. The special signs are, “Attention” and “Break” as per illustrations;
Answering Sign (0) and a “succession of E’s (EEEEEEEEEE)
to indicate that an error has been made. The Erase should be followed
by the last word transmitted correctly and the message continued.
A R means “end of message.”
6. After sending each word the signalman drops his arms to the
break position and waits until the receiver replies with the answering
sign ( C ). If the receiver does not do so the sender repeats the word.
When double letters occur in a word the sender drops his arms
momentarily to the break position and carries on.
7. When vessels are a considerable distance apart and perhaps
signalling with a mechanical semaphore, the receiving vessel acknow¬
ledges each word by means of the answering pendant.
8. When ships are close to one another the semaphore flag (J)
and answering pendant need not be hoisted, but if not, the attention
sign and answering sign (0) may be used instead.
0. When a number of ships are together and there is doubt as to
which vessel is intended to answer the signal, the sender will hoist the
particular vessel’s signal letters, tack line J .
A man-of-war wishing to semaphore to a particular merchant
vessel will' do the same, viz., hoist signal letters, tack line J
and in addition will hoist the Code pendant in a conspicuous position.
T11E INTERNATIONAL CODE OK SIGNALS
645
Use of Procedure Signals and' Signs*
C
The letter C signifies “You are correct.”
When a word, or group, in the text of a message, is repeated back,
the letter “C” is used by the transmitting ship to indicate to the receiving
ship that the repetition has been made correctly.
De (•■ ■« •), *
The word “De” used in the identity signifies: “From-.” Thus:
DeGX DE, “From ship whose signal letters are G X D E”
G (—■ — ■).
The letter G signifies “Repeat back.” It may be inserted at the
beginning of the text of a plain language message, and is signalled
separately. When so used it signifies: “Everything which follows
in this message is to be repeated back, word by word, as soon as received.”
R (« —-)
The letter R signifies: “Message received.”
T (-)
The letter T is used to indicate the receipt of each word in the text
of a 'plain language message.
W (--)
The letter W used as a message in itself signifies: “I am unable to
read your message owing to light not being properly trained or light
burning badly.” This is to be made by the receiving ship at any stage
of the message, if required, and is to be answered by the transmitting*
ship showing a steady light until the receiving ship is satisfied with
the light and ceases to make W,
Call for Unknown Ship and General Call.
The call for unknown ship and general call AA AA, etc. (■—« « —
• — mmmm 9 etc.), is used to attract attention when wishing to signal
to a ship whose name is not known. It is the normal method of calling,
up at sea, and is to be continued until the ship addressed answers.
646
NICHOLLS’S SEAMANSH T P AND NAUTICAL KNOWLEDGE
Answering Sign.
The answering sign TTTTTTTT, etc. — — — — etc.),
is used to answer the call. It is to be continued until the transmitting
ship ceases to make the call.
Space Sign.
The space sign 11 (■ - * -) is used to separate the signs A A, A B,
W A and W B from the identifying words or groups which follow them.
It is also used to separate whole numbers from fractions.
Break Sign.
The break sign B T (— - ■ - —) is used to precede the text. It is to
be repeated back, but its repetition by the receiving ship is not acknow¬
ledged with “C” by the transmitting ship.
Erase Sign.
The erase sign EEEEEEE, etc. (-«■«*.-•, etc.), is used to indicate
that the last word or group was signalled incorrectly. It is to be
answered with the erase sign. When answered, the transmitting ship
will repeat the last word or group which was correctly signalled, and
then proceed with the remainder of the message.
If the mistake was not discovered until after the message has been
completely signalled, a new message must be made.
If it is desired to cancel the whole of a message while in process of
transmissi on, the era se sign must be made, followed by the ending
sign, viz., EEEEEE AR
Repeat Sign.
The repeat sign UD (-- — — ■•) is used to obtain a repetition of
the whole or part of a message.
To obtain a repetition of the whole message.
The repeat sign made singly signifies: “Repeat the last message.”
The repetition is signalled by making the message through in exactly
the same form as it was originally transmitted. Note.— In Sound
Signalling the repeat sign made singly signifies: “I missed nhe last
Word (or group), please go back a few words (or groups) and continue
the message.”
THE INTERNATIONAL CODE OP SIGNALS
647
To obtain a repetition of a part of a message .
The repeat sign is used in conjunction with the signs A A, A B, W A
or W B, and an identifying word or group, the last two being separated
by the space sign thus:—
4t TJD A A II VESSEL,” — signifies: “Repeat all after the
_ word VESSEL.”
“UD AB II JEM — signifies: “Repeat all before the
—. _ — group JEM.”
“UD WA II KIC — signifies: “Repeat the group after
__ KIC.”
“UD WB II FLAGS — signifies: “Repeat the word before
FLAGS.”
If a message is not understood , or tf a coded message , when decoded , is
not intelligible , the repeat sign is NOT used . The receiving ship must
then make the appropriate signal from the Signal Code .
^ Ending Sign.
The ending sign AR (• — « — •) is used in all cases to end a message.
International Code Group Indicator “P R B. M
In messages transmitted by means of the Morse Code, the Inter¬
national Code group indicator “P R D” is to be used as the^first group of
the coded text to indicate that the message which follows consists of
Code groups from the International Code of Signals and not plain
language.
SIGNALLING BY FLASHING
Component Parts of a Message
A message made by flashing is divided into the following components,
although all of these components are not necessarily signalled in every
message:—
1. Call. 2. Identity. 3. Break sign. 4. Text. 5. Ending.
How to Signal.
Component 1 .—The Call —The transmitting ship will commence
signalling by making the call, which will be flashed continuously until
answered.
NTCHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
648
The call consists of:—
(i.) The general call (A A A A A A) etc., or
(ii.) The signal letters of the ship to be called.
On observing the call, and when ready in all respects to read and
write down, the receiving ship will answer by making the answering sign.
Component 2.— The Identity .—It will not always be necessary for two
ships to establish their identity; should such necessity exist the two
ships will carry out the following procedure: when the call has been
answered the transmitting ship will make “de (from)/’ followed by her
signal letters. This will be repeated back The receiving ship will then
signal her own signal letters, which the transmitting ship will repeat
back. If either ship fails to repeat back immediately, or repeats back
incorrectly, the other will make her signal letters again until they are
correctly repeated back.
Component 3.— The Break Sign (BT) is next inserted. It is to be
repeated back, but the transmitting ship does not in this case acknow¬
ledge the repetition by the receiving ship of the break sign (BT) by
making “C” for the reason that it is not a part of the text. If the
receiving ship fails to repeat back the break sign (BT) correctly, the
transmitting ship will make “BT” again until it is repeated back
correctly.
The break sign is not inserted before the text of messages requesting
repetitions.
Component 4c .— The text consists of words of plain language or of
groups of Code. Each word or group is signalled separately. The
receiving ship will—
(a) Acknowledge the receipt of each plain language word with “ T ”
(h) Repeat back all Code groups, numbers signalled as figures
(that is not spelt out), procedure signals and signs except “ C”
and punctuation signs. If the repetition is correct, the
transmitting ship will made “C” if incorrect she will make the
group again.
If the receiving ship does not acknowledge the receipt or repeat back,
the transmitting ship should immediately signal again the last word oi
group.
Component 5 .—The ending consists of the ending sign (AR). The
ending is answered by
THE INTERNATIONAL CODE OF SIGNALS
649
Omitting the Call and Identity.
When two ships are signalling for a considerable period and several
messages are passed between them, the call and identity need be signalled
m the first message only, in order to avoid delay.
Example 1 . —A Simple Message.
Ship Orotava (signal letters 0 N B T) wishes to signal to ship Oroya
signal letters OBEY . the following message: “Owners have agreed to
discharge cargo at Aden.”
Component
Ship Orotava
Ship Oroya
transmits
receives and makes
Call
A A A A A A etc.
TTTTTT etc.
Identity |
De GN BT
GBFY
DeGNBT
— GBFY
Break Sign
BT
BT
r
Owners
T
have
T
agreed
T
Message
to
T
discharge
T
cargo
T
at
T
Aden i
T
Ending
Tr
R
Note.-—T he interchange of signal letters is always repeated in
acknowledgment, but when identity has been established they are not
repeated in further communication between the ships.
Example 2.—A Coded Message.
Messages may be morsed by transmitting the appropriate signal
letters from the Visual Code book.
The letters PUB mean “The International Code of Signals.”
Group KMG means “Owners have agreed to discharge cargo at.”
Group A AO F means “Aden.” An alternative method of Example 1
of making this message would be as follows:—The call and the break
sign are made and answered as usual, but each Code group as above
650
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
when morsed is repeated by the receiving ship and acknowledged by
the transmitting ship making C , meaning correct, before carrying on
with the next group.
Component
f
Transmitting
ship makes
Receiving
ship makes
Call
A A A A A A etc.
TTTTT etc.
Break sign
BT
BT
PRB
G
PRB
Coded
EMC
EMC
message
C
AAGF
AAGF
G
Ending
A R
R
Example 2.—Coded Message as Morsed*
The signalling of the message in Example 2 would appear in Morse
in the following order, the signals in brackets being those of the receiving
ship.
A A A A A A T s
------ ( - )
BT BT P R B PR
— ( -) -— — ( .— —
B G E M G EM G ,
—-) --(---- 1
0 A A C F A A C F ■
-—- - (._- - -)
<7 AR R
Call (Answer) Break sign (Break sign) P R B “International
Code of Signals” (P R B) Correct E M G “Owners have agreed
discharge cargo at” ( EMC) Correct AAOF “Aden** (A AO
Correct Ending (Received)
^ S'
THE INTERNATIONAL CODE OR SIGNALS
651
Example 3.—Ship “ X” to “ Ship “ Y.”
Note.—The replies of Ship “ Y ” are the signals within the brackets .
(—) - . (—>
■ ■ m mmm m (—) ■ m tmm m
H)
«)
Call (Answer) Break sign (Break sign) What (T) is ( T) the (T)
weather (T) forecast ( T) for ( T) to-morrow ( T ) Ending (Received.)
Ship “ Y” to Ship « X.” An example of repeat “ all after.”
Note.—The replies of Ship “ X ” are the signals within the brackets .
. — ( - ) -
— ■ (-)
Call (Answer) Break sign (Break sign)- Cyclone (T) approaching
(T) you (T) should (T) put (T) to (T) sea (T) or (T) strengthen (T)
moorings (Repeat all after, the word or) Repeat all after the word
or (C?) strengthen (T) moorings (2) Ending (Received).
652
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Example 4.—Aircraft to Ship
Note.—The replies from the Ship are the bracketed signals.
— ■ (—) ■ (« — -)
Call (Answer) Break sign (Break sign) What (T) is ( T) my (T)
position ( T) Ending (Received).
Ship to Aircraft.
Example of Numerals and Erase.
Note.—The Aircraft signals are those given in brackets.
- ( ----j
-- (.—)
Call (Answer) Break sign (Break Sign) Position 52° 37' (position
52° 37') Correct Position 81° 46' Erase (Erase) Position 18° 46'
(position 18° 46') Correct Ending (Received)
EXAMPLES FOR EXERCISE.
^ Interpret the following Morse Messages*
---- - (-—) —- -
--- — - --« ---
THE INTERNATIONAL CODE OF SIGNALS
653
654
NIOHOLLS’S SEAM AN SB.if AND NAUTICAL KNOWLEDGE
EXAMPLES FOR EXERCISE.
- Interpretation.
1. Call (Answer) from GPRB (from GPRB) (MLYT) MBIT
Break sign (Break sign) My (T) positron (T) is (T) P 2115 (P 21° 15')
Correct P 3022 (P 30° 22') Correct Ending (Received)
Note.— The message is from the ship holding signal letters GPRB
to the ship whose signal letters ar & M LY T.
THE INTERNATIONAL CODE OF SIGNALS 655
2. Call (Answer) from G D V R (from G D V R) (G M QN)
GMQN Break sign (Break sign) Did (T) you ( T ) sight (T) derelict
( T) Ending (Received)
3. Call (Answer) Break sign (Break sign) Yes (T) dismasted (T)
and (T) decks {T) awash (T) fifty (T) miles (T) south (T) from
( T) Cape (T) Clear (T) Ending (Received)
4. Call (Answer) from GBFY (from G B F Y) (GTRM)
G T RM Break sign (Break sign) P R B (P R B) Correct 0 B B
(0 B E) Correct A A L (A A L) Correct W C (W C) Correct Ending
(Received)
Note. —Refer to pages 548-551 and decode the above International
Code groups as follows:
P RB International Code of Signals
0 B E Take station
AAL On port quarter
W C You should proceed at your utmost Bpeed
5. Call (Answer) Break sign (Break sign) Rendezvous (T) P 23 19
(P 23° 19')
' P 78 45 (P 78° 45') 6 30 (T) PM (T) Ending (Received)
6. Call (Answer) Break sign (Break sign) Have (T) you (T) the
(T) latest (T) Notice ( T ) to (T) Mariners ( T) on ( T) board ( T)
Ending (Received).
7. Call (Answer) Break sign (Break sign) My (T) latest (T) copy
k T) is (T) July (T) nineteen (T) thirty-two (T) Ending (Received)
8. Block Test.
GLPSE KGBXK YXWSO
TJEMYT PLHGY AZGEF
ZVINR TQM IP i DBGXP
FAWJO VURNJ
SIGNALLING BY SOUND.
Caution, —The misuse of sound signalling being of a nature to create
serious confusion in the highways at sea, the captains of ships should
use these signals with the utmost discretion. Owing to the nature
of the apparatus used (whistle, siren, foghorn, etc.) sound signalling is
necessarily slow, and it is for this reason that it is necessary for ships
to reduce the length of their signals as much as possible.
656
NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
(а) Sound signalling in fog should be reduced to a minimum. Signals
other than single-letter signals should be used only in extreme emergency
and never in frequented navigational waters.
(б) For the reasons just stated the procedure indicated in the following
example should be observed.
Example. —You are instructed to signal “What is the depth of
water” by means of the steam whistle, no other system of transmission
being convenient. Describe the procedure.
I would make a succession of double separate A A’s, until the
receiving ship or station answered with T’ s.
I would then morse the message, “What is the depth of water,”
then give {AJR) to indicate signal ended.
The receiving ship or station would then answer with (22) meaning
received.
Assuming the reply to be 19 feet then
She would make A A’s « — - — « — •*— - — - —
1 would answer With T’s mm mm mm* mmm mmm mm
She would make *********** mm * m **** ****»• - ■ —
then (AR) * — -•—«
1 would answer with ( R) - —■ - to indicate that I have received
the message, viz., 19 feet.
Note.—T he transmitting ship sends her message right through
without waiting for acknowledgment by the receiving ship, but if the
receiver misses a word or group he makes the repeat sign ( UD), on
hearing which the transmitting ship will cease signalling and then go
back a few words or groups and continue the message.
QUARANTINE SIGNALS
The following signals are to be shown on arrival by vessels requiring
or required to show their state of health:—
In the Daytime .
Q flag— signifying - - - “My ship is 'Healthy/ and I request
free pratique.”
Q flag over first substitute (Q Q) —
signifying - - - “My ship is 'Suspect/ i.e., I have had
cases of infectious diseases more
than five days ago, or there has
been unusual* mortality among
jfche rats on board my ship.”
THE INTERNATIONAL CODE OF SIGNALS
65 ?
Q flag over L flag ( Q L) — signifying “My ship is ‘Infected,’ i e , I have had
cases of infectious diseases less
than five days ago.”
By Night.
Red light over a white light—
signifying - - - - “I have not received free pratique.”
(Only to be exhibited within the
precincts of a port. The lights
should not be more than 6 ft.
apart.)
DISTRESS SIGNALS
(International Convention for Safety of Life at Sea , Convention
for the Regulation of Aerial Navigation.)
When a vessel or aircraft is in distress and requires assistance, the
following are the signals to be used or displayed either together or
separately:—
In the Daytime.
(1) A gun or other explosive signal, fired at intervals of about a
minute (for vessels only).
(2) The International Code Signal N C, signifying: “I am in distress
and require immediate assistance.”
(3) A continuous sounding with any fog-pignal apparatus; in the
case of aircraft, sound apparatus.
(4) The signal SOS made by Radiotelegraphy, or by any other
distance signalling method.
(5) The distance signal, consisting of a square flag having either
above or below it a ball or anything resembling a ball.
For aircraft -only:— . »
(6) The signal consisting of a succession ol white lights projected
into the sky at short intervals.
(7) The International distress call “MAYDAY” (corresponding to
the French pronunciation of the expression “m’aider”) by
means of Radiotelegraphy.
At Night.
(1) A gun or other explosive signal, fired at intervals of about a
minute (for vessels only).
658 NICHOLLS*S SEAMANSHIP AND NAUTICAL KNOWLEDGE
(2) Flames on the vessel (as from a burning tar barrel, oil barrel,
etc.) (for vessels only).
(3) Rockets or shells, throwing stars of any colour or description,
fired one at a time, at short intervals (for vessels only).
(4) A continuous sounding with any fog-signal apparatus; in the
case of aircraft, sound apparatus.
(5) The signal SOS made by Radiotelegraphy, or by any other
distance signalling method.
For aircraft only:—
(6) The signal consisting of a succession of white lights projected
into the sky at short intervals.
(7) The International distress call “MAYDAY” (corresponding to
the French pronunciation of the expression “m’aider”) by,
means of Radiotelegraphy.
Note.— The instructions for the use of SOS and MAYDAY are
contained in the Radiograph Regulations.
PILOT SIGNALS.
The following signals, when used or displayed together or separately,
shall be deemed to be signals for a pilot:—
In the Daytime .
(1) The International Code Signal 0 signifying “I require a pilot.”
(2) The International Code Signal P T signifying “I require a pilot.”
(3) The Pilot Jack hoisted at the fore.
At Night .
(1) The pyrotechnic light, commonly known as a blue light, every
fifteen minutes.
(2) A bright white light, flashed or shown at short or frequent
intervals j*ust above the bulwarks for about a minute at a time.
(3) The International Code Signal PT by flashing.
GALE WARNING SIGNALS
The Meteorological Office sends to certain Signal Stations a warning
telegram on any occasion when, a gale is expected to occur in the vicinity
of the station. The fact that one of these notices has been received
at any station is made known by hoisting a black canvas cone, 3 feet
high and 3 feet wide at the base, which appears as a triangle when
hoisted.
THE INTERNATIONAL CODE OP SIGNALS
659
The South Cone (point downwards) is hoisted for gales commencing
from a Southerly point; such gales often veer, sometimes to as far as
North-west.
For gales commencing from East to West the South cone will be
hoisted if the gale is expected to change to a southerly direction.
The North Cone (point upwards) is hoisted for gales commencing
from a Northerly point; for gales commencing from East or West the
North cone will he hoisted if the gale is expected to change to a northerly
direction.
RADIO SIGNALS. VOLUME II.
The radio signals are arranged five-letter groups representing
various words, phrases and sentences which might be required to
transact ship’s business by wireless telegraphy. In common with all
telegraphic codes it is necessary to be familiar with the contents and
arrangement of the book in order to obtain from it the most accurate
and economic results. The Code groups and the text are arranged
alphabetically side by side, and a Table is provided so that the receiver
may be able to trace and to rectify an error in a mutilated group as the
Code groups are constructed on an arithmetical system that will ensure
that they will differ from one another by at least two letters and that
no two groups can occur containing the same five letters with a pair
of adjacent letters inverted.
When International Code Signal groups of letters are to be trans¬
mitted by radio the message is preceded by “I N T 0 0” to indicate
that the following is coded from the International Code of Signals.
Bearings, courses numbers, latitude, longitude, time, etc., are expressed
in five-letter Code groups.
When a message is to be sent a series of Code groups are selected to
make up the desired message, the following being an example, taken
from the Medical Section, of one ship asking from another the assistance
of a doctor.
MOGAJ
KV EBP
MOVMI
NANNU
MOT BA
MOTOM
MOTUY
NIMAO
I have a sailor
Age 18
has compound fracture of
thigh
bleeding severely from wound
but has been arrested temporarily by tourniquet
bleeding cannot be stopped
Will your doctor come on board
660
NICHuLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
CATECHISM. ,
1. How many hoists should be shown at a time?
Usually one hoist, but if more than one group of hoists are shown
they should be kept flying until answered by the receiving ship.
2. Name the order in which several hoists should be read when displayed
simultaneously.
(i) Masthead, (ii) triatic stay, (xii) starboard yardarm, (iv) port
yardarm.
3. Suppose more than one group is shown on the same halyard, how
are they separated and read?
They are separated, by a “tack” line about 6 feet long, and the
groups are read in their order from the top group downwards.
4. A vessel is flying several groups of signals on different halyards at the
same yardarm; in what order should they be read?
From the outboard yardarm hoist inwards.
5. Several hoists are shown from different halyards on the triatic
stay; in what order should they be read ?
From forward aft.
6. Define what is meant by superior and inferior signals.
Signals take their superiority from the order and position in which
they are hoisted, the follow up groups being called inferior signals.
The first signal hoisted is superior in point of time to the second one
hoisted, and so on.
Similarly, they take superiority from the position in which they are
hoisted, viz.: ( i) masthead, (ii) triatic stay, (iii) starboard yardarm,
(iv) port yardarm.
7. Describe the procedure of signalling to another ship.
I would hoist my signal letters, and when the other vessel replied by
hoisting her answering pendant close up, or showing her signal letters,
I would hoist each group in turn keeping each hoist flying until it was
answered by the other vessel.
After completing the signal I would hoist my answering pendant
close up. The receiving ship would do the same.
THE INTERNATIONAL CODE? OF SIGNALS
661
8. A vessel is flying your signal letters, what would you do?
She wants to communicate with me. I would hoist my answering
pendant close up When she hauled the letters down I would lower
my answering pendant to the dip and look out for her next hoist.
9. How can one tell if the Code pendant is at the dip?
Unless it is lowered well down it is sometimes difficult to see whether
it is close up or not, especially if flown from the triatic stay, so it is
better to hoist the answering pendant at the masthead ox yardarm.
10 You cannot distinguish the signal made by another ship, or cannot
decode them intelligibly; what would you do?
Keep my answering pendant at the dip and hoist:
U W —I cannot distinguish your flags. Or,
V B —Signal is not understood though flags are distinguishable.
11. How can you tell when a man-of-war is communicating with a
merchant ship?
She flies the Code pendant in a conspicuous position during the
whole time the signal is being made.
12. Decode the following signals from the specimen code given on
pages 636 to 639:—
“Ship A hoists”
(i) L J. (ii) A AG G\ (iii) Code flag.
(l) I am disabled; will you tow me into
(ii) Aden
(iii) Signal completed.
“Ship B hoists”
(i) 0. (ii) PFQ. (iii )OBE. (iv)AAC. (v) COL. (iv) Code flag.
(i) Yes
(ii) You should have a towing hawser ready
. (iii) Am taking station
(iv) Three points on the port bow
(v) You should send your boat to pass towing haserw
(vi) Signal completed
13. Decode the following signal and explain the procedure and inter*
pretation:—
(i )GNBT. (ii )OGN. (iii) GLY F
662 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
v i) The first signal-letter hoist indicates that the signal is addressed
to ship Orotavo,
(li) Means “Your boat should keep to leeward until picked up.'*
(iii) The second signal-letter hoist indicates that the message ,**
from ship Orsova instructing Orotavo what to do.
14. How is a geographical signal distinguished?
It is a four-flag hoist with letter A on top.
15. Are there any pther special four-flag signals?
Yes; ship signal-letters are always four-flag hoists, the top flag
and, in some cases the top two flags, of which indicate the nationality
of the vessel. Thus letter G or M on top indicates a British vessel.
16. What is a substitute and what is it for?
A substitute is a triangular flag. There are three substitutes, 1st,
2nd and 3rd. They are used when a letter is repeated in a group,
thus, A ABB would appear when hoisted as A 1st substitute, B 3rd
substitute.
17. How is a numeral signal made?
By means of the numeral pendants, simply by bending them together
in the order to make up the number, introducing substitutes when
double figures appear in the groups.
18. How are position signals in latitude and longitude distinguished?
The top flag is P, followed by the numeral pendants giving the
latitude and longitude.
19. How are time signals recognised?
The top flag is T, followed by numeral pendants giving the time
in hours and minutes as per the four-figure notation.
20. If you are signalling the exact time by flags, or Morse, how is the
exact instant transmitted to the other vessel?
An even minute is chosen and the hoist intimating the hours and
this minute is hoisted a few minutes in advance. The signalman, as
the time approaches, is on the alert to haul down the flags sharply
whenever a timekeeper stationed at clock or chronometer calls out to
him to do so. The moment of lowering the hoist sharply is the exact
minute. The same system is adopted when morsing an even minute -of
THE mTERSTATtOlsrAt, CODE 0£ StGHALS
663
time. The time is signalled first, then a long fiash is shown, the end of
the fiash being the exact time that has previously been signalled.
21 How are course and bearing signals distinguished?
By letter X being the top flag of the numeral hoist indicating the
direction. Courses and bearings are given in degrees, true from 0° to
359°.
Bearings are signalled in the order
Bearing from Distance from Place
22 In the absence of the Code book, how may communication be
established with International Code flags?
By spelling out each word, the preliminary hoist being Code over E,
meaning “I am going to spell the words.” Code over F is hoisted after
each word, and Code over G is hoisted when the spelt message is finished.
23. What is a <e weft ” ?
A weft is a flag with its fly tied to the halyards. It is now obsolete.
A weft was introduced to cover the period of transition from the
old to the present system of signalling, a period during which both
Codes were in use. The Code pendant as a weft, for example, meant
<e I wish to signal with the new International Code.” This is no
longer necessary.
24. When and by whom must National colours be shown!
By all British vessels when entering or leaving foreign ports, and
on a signal being made from a Government ship. Vessels under 50 tons
gross are exempted when entering or leaving British ports, so also are
registered fishing vessels.
The master is liable to a fine of £100 for contravention of this
regulation of the Merchant Shipping Act.
25. How is the signal “Man Overboard” made?
By hoisting flag 0, and Morse O made on the whistle or by flashing.
26. What is the flag hoist for (a) in distress, (b) want a pilot?
(a) Letters N O or W, (b) letters P T or G.
27. Describe flag letter C.
A square flag having five equal horizontal stripes in the order
downwards—blue, white, red, white, blue.
664 NICHOLAS'S SEAMANSHIP aND NAUTICAL KNOWLEDGE
28. What is the Morse call sign and its answer?
A succession of double separate A’s, answered by a succession of T *a
29. What does B T (— ■ ■ - —) mean?
Just a break between the call up and the text of the message to be
transmitted. It also serves to indicate that the receiver is ready’to
read. It is answered by the receiving ship repeating it back.
30. What does G (—» ■— •) signify?
It indicates that the sender wishes the receiver of the message to
repeat back everything word for word as received instead of replying
to each word by the general acknowledgment T.
31. What does W («—■—) signify?
It is made by the receiving ship at any stage of the message to
inform the transmitting ship that her signal light is not properly trained
or burning badly. The transmitting ship should show his signalling light
steady whilst adjusting it until the receiving ship ceases to make IP’s.
32. What is the space sign?
The space sign is II («- «■) and is used to separate the repeat
signs A A A B W A and W B from the words or groups asked to
be repeated.
33. How may a mistake in sending be rectified?
By the sending ship making Erase («------) a succession of E* s,
which is repeated by the receiving ship. The sender then repeats the
last word or group which was correctly signalled and carries on with
the rest of the message.
34. What does UD (* «»** « ») mean ?
It means repeat the message, or such part of it as may be indicated
by A A (ah after), A B (all before), W A (word after), W B (word
before).
33. Describe flag letters D, E, F, G.
D is yellow, blue, yellow horizontal stripes, the blue being treble
the depth of the yellow stripes.
E is blue over red horizontal half and hall
F is white with a red diamond.
Q is six equal vertical stripes yellow and blue*
THE INTERNATIONAL OODE OF SIGNALS
665
36. Describe the three substitutes.
The substitutes are triangular flags.
1st substitute is yellow with blue border.
2nd substitute is blue with white fly.
3rd substitute is white with a horizontal black stripe across the
middle of it.
37. What are the functions of the Code flag?
(а) When hoisted preliminary to signalling it means that the 1931
International Code is to be used.
(б) When hoisted at the dip by a receiving ship it means signal seen,
and when hoisted close up it means signal understood.
(c) It is used as an answering pendant to acknowledge each hoist as
received.
(d) It indicates the decimal point in a numeral signal
{e) It is associated with letters E 9 F and G 9 when spelling opt words.
EXAMINATION PAPERS.
SECOND MATES.
Cargo Work and Elementary Ship Construction.
B.T. Specimen Paper. (3 hours)
1. If you sounded a double bottom tank and found 16 feet of water,
what action should be taken?
2. What is a displacement scale ? State its uses.
3. How is the draught of a vessel affected when passing froro salt
water to fresh water? Give reason The loaded draught of a
vessel is 22 feet 6 ins. and the fresh water allowance inches.
The vessel is loading in dock, density of water 1016. Calculate
draughts forward and aft, to which you would load, vessel to be
6 inches by the stern.
4. What is meant by (a) centre of gravity; (b) centre of buoyancy?
5. What are deep tanks and why are they fitted ?
6. Give a brief description of (a) deck stringer; (b) panting beam;
(c) beam knee.
7. What is a bilge keel? Give a rough sketch.
8. What precautions must be taken when loading general cargo for
several ports?
9. State fully how a cargo of rice is stowed in a ship.
Paper 1.
1. What arrangements of derricks would you suggest for loading
cargo and lifting 5 cwt. per sling?
2. How would you prepare a hold for loading a cargo of coal
Describe the system of ventilation you would adopt.
3. Describe the gear you would use to take in bunker coal from a
lighter in bags when filling the side bunkers.
4. Sketch and describe an arrangement of portable hatchway beams
667
663
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
5. Name the several components of {a) the transverse framing;
(b) the longitudinal framing.
6. What are “strum” boxes and what precautions must be taken
with them'?
7. Two hundred iron tanks 3 ft. x 3 ft. X 2 ft. 6 ins. are stowed
when empty in No. 3 hold, the ship’s mean draught being then
18 ft. 6 ins. The tanks were then filled with beans in bulk at
48 cubic feet per ton. What will the mean draught be when the
tanks are filled, the ship’s T.P.I. being 35 ?
8. Find the total load on a double purchase and the pull on the
hauling part of the fall when rove to advantage and lifting 20
cwt. . State what allowance, if any, you have made for friction.
Paper 2.
1. How is the density of sea water ascertained ? Distinguish between
•"density ” and <c specific gravity.”
2. A cargo of grain in bags has just been discharged, describe fully how
you.would prepare the holds and be ready to load a general cargo.
3. A vessel at a mean draught of 14 feet has a deadweight of 1372 tons
and at 15 feet mean draught her deadweight is 1588 tons. If the
vessel has a mean draught of 14 ft. 6 ins. and loads an extra 50
tons, what would be her new mean draught, and what deadweight
would she then have on board ?
4. Sketch (a) a lap joint; (6) a butt strap joint.
5. What are the advantages and disadvantages of the “joggled” and
the “ out and in ” systems of plating? Illustrate by sketches.
6. What are “ crutches ” and “ panting beams ” ?
7. Assuming the righting levers (GZ's) of a ship at 10° heel to be -5 ft.;
at 20% 1”1 ft.; at 30% 1*6 ft.; at 40% 1*95 ft.; at 50% 1*7 ft*;
at 60% 1*1 ft.; at 65% *5 ft: construct a graph and from it find
the righting arm at 25% also the “ range” of the ship’s stability.
8. A caisson when filled with ballast weighs 10 tons and measures 200
cubic feet. What weight will be on the crane when the caisson is
lowered into sea water?
9. A derrick is at an angle of 40° from a vertical mast. A weight of
10 tons is being lifted with a guntaekle purchase, the hauling part
leading from the upper block down the derrick to a winch at the
heel of the derrick. Find the stress on the shackle at the derrick
head, allowing one-tenth for friction at each sheave.
EXAMINATION PAPERS
669
Paper 3.
1 How would you prepare a hold for a full cargo of jute, and how
would you stow the bales ?
2 Describe the preparations you would make regarding winches and
cargo gear preparatory to discharging cargo.
3 Is ventilation provided for the bilges when a ship is fully loaded ?
Give reasons.
4 A ship’s hold is 50 feet long, 28 feet broad and 20 5 feet deep In
it is stowed a tier of barrels which go 250 to the tier. Each
barrel stows at 12 cubic feet. What is the height remaining over
the top of the barrels ]
5. What is the function of a pillar] Show by a sketch how the head
and heel of a pillar are connected to its adjacent parts.
6. What arrangements are made to allow water to flow from one
transverse section to another ?
7. Cargo has just been discharged from a deep tank, describe exactly
what should be done before the order to fill it with water can be
given.
8. A steamer’s draught in light load condition is 10 ft. 6 ins. aft, 7 ft.
8 ins. forward. The following ballast tanks are then filled with sea
water—No. 1, 186 tons; No. 2, 498 tons; No. 3, 219 tons; No. 4
221 tons; also her permanent bunker space of 19,980 cubic feet
with coal at 45 cubic feet per ton. Assuming the T.P.I. to be 30,
find the ship’s new mean draught if she trims 2 feet b j the stern.
#
Paper 4;
1. Describe in detail how you would prepare a hold for a cargo of grain
in bulk.
2. How and where would you stow glass and grindstones as part of a
general cargo ]
3. What precautions against fire are taken when loading cotton?
4. A hold has a cubic capacity of 38,640 feet. At the bottom of the
hold 643 packages (2 ft. X 1 ft. X 1 ft.) and weighing 200 lbs.
are placed; 5 per cent, of the cubic capacity of the Cargo is allowed
for broken stowage. On top of this a parcel of 325 tons of wheat
is placed stowing at 55 cubic feet to the ton. What tonnage
remains in the hold at 40 cubic feet to the ton ]
670
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
5. Define what is meant by the terms “ centre of gravity ” and “centre
of buoyancy” as applied to a ship.
6. A box-shaped vessel when light has a mean draught of 2 feet and
its loaded draught is 10 feet forward and 11 feet aft. If the T.P.I
is 10, how much cargo can be loaded m the vessel ?
7. What faulty distribution of cargo would produce (a) hogging;
(b) sagging; (c) collapsing stresses?
8. Sketch and describe how beams are connected to the frames.
9. Draw a figure of the load lme marks of a steamship, naming the
several lines, and state to which edge a vessel is loaded.
Paper 5.
1. Is it advisable to use a swinging derrick when unloading a bag cargo?
Give reasons.
2. State fully how you would dunnage and load a cargo of cement in
barrels. '
3. What precautions, if any, should be taken with deck winches in
cold weather? Steam is escaping badly from the cylinders of
a winch, what is this due to and how is it remedied ?
4. What principal purposes do transverse watertight bulkheads fulfil ?
5. What is a stringer plate? Sketch and describe how it is fitted at an
upper deck.
6. The sea-cock of a double bottom is left open, the waterline is 10 feet
above the top of the tank, the area of which is 1500 square feet.
What is the total upward pressure on the tank top?
7. Given the following data, construct a graph:—
Mean draught 2 ft. 3 ft. 5 ft. 7 ft.
T.P.I. 4*7 tons 10*7 tons 13*6 tons 15*5 tons.
If the vessel loads 40 tons of cargo at a mean draught of 4 feet,
what is the change of draught.
8. What is meant by “ pounding ” and how is it counteracted ?
9. Draw the following to scale:—Length of derrick 50 feet; from heel
of derrick to span on mast 40 feet; angle between derrick and
mast 30°; weight suspended from the end of derrick, 3 tons.
From your figure find the approximate thrust on the heel of the
derrick and the strain on the span.
EXAMINATION PAPERS
671
Paper 6.
1. How is a cargo of rice ventilated ?
2. Describe the permanent and portable dunnage usually fitted in ships.
3. Describe the usual arrangement of derricks and winches in an
ordinary cargo ship.
4. Where should the following goods be stowed, and why:—Acids,
explosives, oil in barrels, tallow?
5. Sketch an ordinary floor, describe it and name the parts to
which it is attached.
6. What are “ breasthooks ” ? Where are they placed, and why ?
7. A hold of capacity 42,000 cubic feet has in it 150 tons of iron,
stowed at 12 cubic feet per ton. How many bales of esparto grass
can be stowed in the hold at 100 cubic feet to the ton and allowing
6 bales to the ton ?
8. Define “ centre of gravity ” and state how it would be found in (a)
a square plate; (b) a circular plate, omitting the thickness of the
plate.
9. Explain why a piece of steel sinks when thrown into the water, and
why a steel ship does not sink.
Paper 7.
1. Sketch a barrel and name its parts, including hoops.
2. How would you separate (a) parcels of timber; (6) parcels of rod iron?
3. How would you stow boxes of green fruit? Describe the arrange¬
ments made for ventilation.
4. How is a cargo of frozen meat ventilated? What precautions are
taken when loading?
5. A ship’s hold capacity is 34,440 cubic ft. 745 tons of coal are stowed
in it at 42 cub. ft. per ton. 225 tons of rails are then put in to
fill the hold. Find the stowage capacity of the rails.
6. Describe a watertight bulkhead and how it is connected to the
adjacent parts.
7. What was the length of your last ship? How many bulkheads had
she and how many of these were watertight?
8. A homogeneous log of rectangular shape measures 12'x2'xJ'.
It floats in F.W. at a depth of 9 inches, what is its weight? f
672
NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
9. Construct a displacement curve for the following*—
Displacement tons 334 1020 1950 2930 3830 4840
Draught 2' 6" 5' 0" 7' 6" 10' 0" 12' 6" 15' 0"
Find draughts corresponding to 2340 and 4500 tons displacement.
Using above curve if the vessel started loading at 7' 6" draught
and while loading she pumped out 510 tons ballast, find the cargo
loaded if she completes loading at 15 feet draught.
Paper 8.
1. How would you tally a general cargo and what would you note m
the tally book?
2. How do you stow a riding tier of barrels? How high do you stow
barrels, hogsheads, puncheons, butts? State the capacity of
each in gallons.
3. Describe the construction of a grain feeder used when loading grain
in bulk. What percentage of the cargo should it contain?
4. How and where are explosives stowed? What precautions are
taken when loading?
5. A hold having a capacity of 36,218 cub. ft. has stowed in it 212
tons of steel. The remainder of the space contains 626 tons of
coal stowing at 45 cub. ft. Find the stowage of the steel in cub. ft.
per ton.
6 Sketch and describe a single plate rudder.
7 What is the angle of maximum efficiency of the rudder and what
prevents it going over too far?
8. A homogeneous log 8' long and 18" diameter floats half submerged
in F.W., find weight of the log.
9 Construct a T.P.I. ’curve from the following data:—
Draughts 2 ft. 5 ft. 8 ft. 11 ft. 14 ft.
T.P.I. 8 13-5 16*2 17*7 18*5
Find T.P.I for draughts 7, 12 and 13 feet.
At a draught of 10 feet the vessel takes on board 25 tons F.W.,
find hef new draught.
Paper 9.
1. How is cargo prevented from touching the ship's side while loading,
and what additional precautions are taken when loading rice or
a similar cargo?
EXAMINATION PAPERS
673
2 What is “broken stowage” and where is it most likely to occur?
3. What would you do when discharging if you found damaged cargo?
4. What are shifting boards? When are they necessary and how are
they erected?
5. The capacity of a hold is 48,696 cub. ft. In it are stowed 312 tons of
slab marble at 18 cub. ft. per ton. How many cases of macaroni
can be stowed above the marble if 35 cases occupy a ton space of
40 cub. ft.?
6 Sketch and describe a stem frame.
7. How is a propeller secured to the shafting?
8. A vessel has four W.T. bulkheads in the double bottom. How are
the pipes led to the forward tank and how are they led through
the bulkhead?
9. Construct a curve of displacement having given:—
Displacement tons 270 830 1370 2020 2750 3630
Draught in feet 2' 4' 6' 8' 10' 12'
(a) If the vessel’s draught when light is 6' 4", what is her dead¬
weight, her load draught being 12 ft.?
(b) If she has 510 tons of ballast on board what would her mean
draught be?
Paper 10.
1. Describe the duties of a second mate when loading the following
cargoes:—(a)' A heterogeneous cargo, (b) Rice in bags from
lighters. ( c) A bag cargo of wheat for three ports.
2. Freight is charged at 24s. to the ton, measuring 40 cub. ft. per ton.
A package 10' 6"x4' 6 // x7 // weighs 7 tons 4 cwts. Find the
freight (a) by weight; (b) by measurement.
3. What are intercostals? How are the compartments in a C.D.B.
made accessible foT inspection and cleaning?
4. What is a stem bar? How is it connected to (a) a bar keel; (b) to &
flat plate keel?
6. A ship has a deep tank extending the breadth and depth of the
vessel and has double bottom tanks of the same capacity. Will
there be any difference in the effect of the C. of G. if these tanks are
filled separately, and if so, for what reason?
674
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
6. A ship’s starboard double bottom tank was filled up, how would
this aflect her centre of gravity?
7. A block of marble weighing 1 ton falls into the dock while dis¬
charging; would the strain on the cargo gear when lifting it to the
surface of the water be greater or less than when lifting it out of
the hold? Give reasons.
8. If a vessel displaces 100 tons in salt water what weight will she
displace in F.W.?
9. Displacement tons 376 736 1352 2050 3140 4450
Draught in feet 2' 4' V 10' 14' 18'
At draught 8' 8" she loaded 750 tons and discharged 100 tons, find
new draught. When she had discharged 2973 tons cargo and taken
in 725 tons water her draught was 9 ft. Find her original draught.
Paper 11.
1. When discharging a bag cargo you find some bags empty and some
torn, what action would you take?
2. How would you prepare a hold for, and stow, a cargo of frozen
meat?
3. In what direction does heated air travel in a confined space? And
of what benefit is this knowledge to a ship’s officer?
4 Hold capacity 41,500 cub. ft., 14,500 bags of cement, weighing 112 lbs.
per bag, are stowed at the bottom, the rest of the hold is filled with
403 measurement tons of 40 cub. ft. Find how many cub. ft. per
ton the cement slows at.
5. How are dirt and mud prevented from entering the pipes used to
pump out bilges and ballast tanks?
6. Describe a hatch coaming and how it is strengthened, and what parts
of the structure are connected to it.
7. Describe and name the parts of a complete transverse member of
an ordinary cargo steamer having cellular double bottom.
8. What is displacement? If the total volume of the immersed part
of a vessel is 85,750 cub. ft., what is the equivalent in tons when
the vessel floats in salt water?
9. Mean draughts 3 ft. 6 ft. 9 ft. 12 ft. 14 ft.
T.P.I. 10-7 14*7 16*8 18*0 ‘ 18*5
Find T.P.I* at 5, 7 and 13 ft. If the mean draught is 7 ft. and the
vessel discharges 45 tons, find her new draught
EXAMINATION PAPERS
675
Paper 12.
1. With two derricks at a hatch, ng cargo gear for starboard side, to
lift 30 cwt. at a time.
2. A hold has a capacity of 35,530 cab. ft. In it are stowed 10,400
bags of cement, each weighing 70 lbs. and stowing at 35 cub. ft. to
the ton. How many cases stowing at 22 per ton of 40 cub. ft. can
now be stowed in the hold?
3. Describe how a centre through plate is connected in a C.D.B.
4. What is a margin plate? How is it connected to adjoining parts?
5. Explain carefully why some woods float and others sink?
6. A motor vessel bums all the fuel oil in her D.B. tanks, what eflect
will this have on her centre of gravity?
7 * A vessel's volume of displacement is 393,503 cub. ft. Find her
displacement in tons (a) in water density 1025; (5) in water of
density 1015, at same draught.
8. From a scale of deadweight the following was taken:—Draught 18 ft.
D.W. 4800 tons. Draught 18' 6", D.W. 4980 tons. How many
tons of cargo would be required to immerse the vessel from 18' 1"
to 18' 4" and what deadweight is there on board at the latter
draught?
9. A homogeneous log of 18" square section floats at even draught of
3" with one face parallel to the surface of the water; find the height
of the centre of gravity above the centre of buoyancy.
FIRST MATES.
Ship Maintenance, Routine, and Cargo Work.
B.T. Specimen Paper. (3 hours)
1. Your vessel has sustained damage leaving harbour. Where and
how should this be recorded ?
2. How often should the crew be exercised at boat drill ? Draw up
your routine for boat drill.
3. The bilges of your ship are choked and very dirty. State in detail
how you would clean them.
4. What precautions must be taken when loading a full cargo of sawn
timber ?
5. How should a magazine for explosives be constructed ?
!
676
NICBEILLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
6. The derricks of a vessel are tested to lift 5 tons each, no heavy
derrick being available. There is a weight of 6 tons to be lifted
out of the hold. What gear would you rig to land this weight on
deck ?
7. One of the steering chains has carried away. What action would
you take %
Paper 1.
1. Describe types of slings and gear used for slinging different kinds of
cargo.
2. Ship in ballast trim, you are to load general cargo in all holds.
When and what tanks would you pump out, and give reasons ?
3. Describe how you would prepare a ship for a cargo of grain in bulk
when loading at a port in U.S A.
4. Describe how a wood deck is fitted on transverse beams. How
would you prevent decay in wooden decks ?
5. What entries are made in the mate’s log book in port ? Why is
accuracy important with regard to log book statements ?
6. A derrick 40 feet long has to lift a weight of 6 tons with a guntackle
purchase. The span is made fast 50 feet above the heel and the
purchase fall is led down the derrick. Find the stress on the span
and the thrust on the derrick, assuming the weight plumbs a point
25 feet from the mast.
7. Describe the emergency steering gear of any ship you have served in.
Paper 2.
1. Prepare holds for a general cargo. Describe how you would stow it
and distribute the weights.
2. What particulars would you give when indenting for the following
stores:—Canvas, paint brushes, blocks, manila rope, shackles, reel
for mooring wire, lugsail for life-boat, nuts and bolts ?
3 The ship has just completed loading. State all that should be done
with regard to hatches, cargo gear and cleaning up the decks
preparatory to going to sea.
4. You are responsible for receiving cargo. What precautions should
be taken to safeguard the ship’s interests ?
EXAMINATION PAPERS
677
5. A ship of 3520 tons deadweight has on board 490 tons of stores,
water and bunkers. Her hold capacities are No. 1, 55,100 c.f:
No. 2, 55,970 c.f: No. 3, 44,100 c.f: No. 4, 35,900 c.f. It is
required to stow phosphate at 35 c.f. per ton, and hay at 120 c.f.
per ton to maximum capacity; find the quantity of each.
6. You are loading the following cargo:—What form of slinging would
you adopt and what quantity per sling (i) iron tubes; (ii) bales;
(iii) bags of salt; (iv) cement in casks; (v) oilman’s small stores;
(vi) reels of paper?
7. A span is formed by two pendants which make angles of 30° and 50°
with two vertical masts. A load of 8 tons is hanging from the
span ; find by construction the load on each pendant.
Paper 3.
1. Describe in* detail the rigging of a heavy derrick to lift a weight
of 40 tons.
2. The bilges are rusted, how would you clean them and prevent
subsequent rusting ?
3. Where would you expect to find early indications of corrosion in a
ship and state what you attribute the cause to ?
4. Describe fully how a cargo of rice is stowed, dunnaged and
ventilated.
5. What is meant by “ ullage ” in a tanker ? What special precautions
are taken when carrying petroleum spirit in bulk ?
6. Describe the operation of dry docking a ship.
7. Loading esparto grass in bales (110 cub. ft. per ton) and ore in bags
(15 cub. ft. per ton); ship’s d.w. 3500 tons; stores, water and bunkers
480 tons; hold capacities, No. 1, 36,000 cub. ft.; No. 2, 37,500 cub.
ft.; No. 3, 37,200 cub. ft.; No. 4, 35,300 cub. ft. Required the
quantity of each to fill the ship to capacity. Draw a cargo plan
and dispose the cargo in a single deck ship.
8. Two masts each 45 feet in height are 80 feet apart. Between the
masts are two spans, one 35 feet, the other 60 feet long. At the
point where they join a gun tackle purchase is made fast, the
hauling part leading down to a winch at the nearest mast. Find
the stress on each span when lifting a weight of 2 tons, allowing
for friction.
67&
NICHUiiLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Paper 4.
1. How are the following goods stowed:—Frozen mutton, chilled beef
bananas ?
2. Describe the cargo gear carried in your last ship.
3. Discuss the question of dunnaging cargoes and what you consider to
be a reasonable amount for various cargoes. What precautions
would you take against the pilfering of cargo ?
4. What precautions should be observed at sea when carrying a cargo
of coal ?
No. 2 hold is heating very considerably, what would you do to
prevent the coal going on fire ?
5. Describe a type of steam steering gear and how the rudder is
operated by the helmsman.
6. Coal is loaded into the bridge space banker from six barges whose
holds are 50 ft. long. X 6 ft. deep X 18 ft. wide at top X 16 ft.
wide at bottom. After steaming for 12 days there remains a
wedge of coal against a bulkhead whose triangular end is 6 ft.
high X 10 ft. wide and whose length is 50 ft., also two full coal
shoots each 4 ft. 6 ins. X 4 ft. 6 ins. X 22 ft. deep. Find the
consumpt per day if the coal stowed at 45 cub. ft. per ton.
7. A derrick at an angle of 50° with a vertical mast is supported by a
topping lift making an angle of 40° with the mast. Find the
thrust on the derrick and the tension on the lift when a weight
of 8 tons is suspended from the head of the derrick.
Paper 5.
1. How would you make cargo hatch openings perfectly watertight
and secure ?
2. You are loading the following cargo, in No. 2 hold, an equal
weight of each item, construct your cargo plan and describe the
maimer of stowing and protecting the goods (a) iron tubes;
' (b) bales; (c) bags of salt; (d) cement in casks; (e) oilman’s stores;
(/) reels of paper.
What stevedoring precautions should be taken when handling any
of those goods 7
3. A vessel of 5000 tons d.w. has 500 tons of coal and stores on board.
She is to load 1000 tons manganese in bags at 25 cub. ft. per ton.
Her total hold capacity is 275,000 cub. ft. Find the quantity of
EXAMINATION PAPERS
679
jute at 66 cub. ft., and copra at 80 cub. ft., she can stow in the
remaining space.
4. Describe the fire appliances in your last ship.
5. Why are the mate’s receipts for cargo received of commercial
importance? What particulars should he verify before signing ?
6. Describe the load line marks on a ship over 330 feet in length.
7. What guarantee have you that the anchors and cables are in
good order ?
8. You join a strange ship as chief officer, what investigations would
you make regarding her deck equipment, condition of holds,
tanks and the ship’s condition generally ?
Paper 6.
1. Lifting a weight of 15 tons with a luff-tackle rove to disadvantage,
find the total load on the upper block and the pull on the hauling
part which is led vertically down, allowing 10 per cent, of the
weight for the friction of each sheave.
2. What life-bo at equipment must a cargo ship be provided with ?
3. Describe bulkhead sluice valves and the attention they require.
4. Draw up a station bill for fire drill for a cargo steamship of 5000
tons deadweight.
5. What should the chief officer of a ship attend to with regard to
receiving and stowing cargo for several ports ?
6. A vessel has steamed 1600 miles at 12 knots on 32 tons of coal per
day, find her speed to do 1800 miles with only 150 tons
remaining.
7. State what you know of the conditions attached to carrying timber
deck cargoes.
8. You are about to load a cargo of rice (50 cub. ft. to the ton).
Ship’s deadweight 4200 tons. Bunkers 450 tons. Cargo 900 tons
for London, 900 tons for Hamburg, 1000 tons optional (London or
Hamburg) and the remainder for Havre. Hold capacities No. 1,
42,500 cub. ft.; No. 2, 52,000 cub. ft.; No. 3, 50,800 cub. ft.;
No. 4, 42,200 cub. ft. Show on a cargo plan how you would
distribute this cargo. Order of discharge: Havre, Hamburg 1 ,
London.
What precautions would you take with regard to stowage
f dunnage, separation and ventilation?
680
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Paper 7.
1. What is mill scale? Is it injurious or does it help to preserve the
plate? How is it treated?
2. In ballast, loading at a single coal tip, when would you pump out
your ballast tanks and in what rotation? What special precautions
would you take?
3. Enumerate the entries made in the mate’s log at sea, in port,
and when lying at anchor.
4. Discuss the methods of ventilating a general cargo.
5. Describe fully how you would stow bag grain and state the
precautions you would take against damage from sweat.
6. Describe in detail the construction of feeders for a bulk grain cargo.
7. A square cargo tray 4 feet by 4 feet, slung with four legs each 6 feet
long meeting in a ring at the top, supports a weight of 15 cwts.
Find the stress on each leg of the slings.
8. Stow any four of the following in one hold of an ordinary ’tween deck
steamer:—Brigs of manure, bags of flour, drums of asphalt, cases
of dried fruit, cases of canned goods, cases of tinplate, barrels of
cotton seed oil, bags of grain.
Draw a rough cargo plan showing the method of stowage, dunnage,
separation and ventilation.
Paper 8.
1. What ventilation would you provide for green fruit in boxes for a
short passage?
2. How would you separate different parcels of (a) coke, (6) rod iron,
and (c) sawn timber?
3. What is the rough log and who keeps it?
4. Describe a suitable routine for the inspection and upkeep of lifeboats
and life-saving appliances.
5. What precautions should be taken when pumping and draining
double bottom tanks with one centre suction at the after end?
6. What precautions would you take when renewing deck planks
over a steel deck?
7. A vessel 3890 tons deadweight has on board coal, stores and fresh
water amounting to 520 tons. The hold capacities are;—No. 1
52,200 cub. ft.; No. 2, 55,600 cub. ft.; No. 3, 44,500 cub. ft.; No. 4, %
EXAMINATION PAPERS
681
40,200 cub. ft. The vessel has to be loaded down to her marks
with the maximum quantities of wheat stowing at 48 cubic feet
per ton and oats stowing at 80 cubic feet per ton. Required the
quantity of each.
8. A beam 8 feet long weighs 4 tons. Find the minimum length of
each leg of the slings required to support the beam if the safe
working load of the only available wire is tons.
Paper 9.
1. What routine duties would you assign to the carpenter?
2. A ship’s company consists of the master, 3 mates, 4 engineers, 1 W/T
operator, 4 stewards, 10 sailors, and 11 firemen. Draw up a plan
of boat stations and allot duties to each man.
3. A white painted steel deckhouse shows signs of corrosion. State
fully how you would treat it.
4. How would you mix cement for application to a double bottom and
how would you apply it?
5. Describe how you would stow a full cargo of iron ore (a) in a ’tween
deck vessel; and (b) in a single deck vessel.
6. What is me&nt by “bleeding” bags? Would you advocate this
procedure?
7. A derrick makes an angle of 50° with a vertical mast and 12 tons is
being lifted with a double purchase. Find the stress on the shackle
at the derrick head allowing 10 per cent, for friction, also the
stress on the shackle at the lead block at the derrick heel if the
winch is 10 feet from the heel of the mast.
8. Find the approximate amount of paint required to cover the ship’s
bottom up to 15 feet draught allowing 1 cwt. of paint per 3000
square feet. Length 280 ft., breadth 38 ft., coefficient of fineness
*80.
Paper 10.
1. What entries are made in the mate’s log after a collision?
2. What are the merits and demerits of patent driers? How would
you treat lifeboat air tanks with a view to preserving them?
3. Describe in detail how you would treat new hatch covers and
tarpaulins.
683 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
4. How do you measure rope and find its safe working load? How
do you measure blocks? What size of block would you use with 2|"
wire and with 3" manilla rope?
5. What are the duties of a watchkeeping officer with regard to
ventilation of cargo?
6. (a) What is the difference between grain space and bale space?
(b) Distinguish between deadweight and measurement cargo.
7. Ship 3300 tons deadweight. Stores and fuel 440 tons. Loading
cotton at 70 cubic feet per ton as follows:—Osaka 900 tons; Osaka-
Kobe (optional) 1000 tons; completing for Kobe. The hold
capacities are:— No. 1, 49,700 cub. ft.; No. 2, 51,350 cub. ft.; No. 3,
41,570 cub. ft.; No. 4, 36,000 cub. ft. Describe the stowage,
dunnage, separation and ventilation.
8. A three-fold purchase is used to lift out a 2-ton weight. A luff tackle
is attached to the hauling part of the purchase. Find the minimum
force required to lift out the weight and the stress on the supporting
shackle allowing 10 per cent, for friction.
FIRST MATE.
Ship Construction and Stability.
B.T. Specimen Paper. (3 hours)
1. Sketch and name the various rolled sections used in ship
construction.
2. What is the usual method adopted for distinguishing the strakes
and plates of a ship ?
3. What is a web frame ? Give a rough sketch showing how it is built
up.
4. Name the different members of the transverse framing in a ship with
ordinary floors.
5. Define (a) reserve bouyancy, (6) displacement, (c) centre of gravity,
(d) centre of buoyancy.
6. How does increase of freeboard affect stability ?
7. In a vessel of 3000 tons displacement a weight of 100 tons is moved
20 feet, and a weight of 50 tons moved 10 feet upwards in a
vertical direction.* Calculate the effect on centre of gravity.
8* What is meant by a vessel being {a) stiff, ( b ) tender ? What effect
has the flooding of a double bottom tank on the stability of a ship?
EXAMINATION PAPERS
683
Paper 1.
]. Show by means of a sketch, how a frame and reversed frame are
connected to a floor plate, indicating clearly the various
connections.
2. What is a stringer ? Sketch and describe a deck stringer
3. When and where are web frames introduced ?
4. What stresses is a vessel in a seaway subjected to ?
5. What is meant by a vessel being stable and unstable ? Illustrate
by sketches.
6. How is a curve of buoyancy constructed ?
7. What is a bilge keel ?
Paper 2.
1. Name the component parts of a transverse section of a ship having
cellular double bottom.
2. Sketch a bar keel and a flat plate keel and explain how they are
connected to the hull.
3. What system is adopted in a shipyard to identify a particular plate
of shell plating %
4. Name the several parts which contribute longitudinal strength to the
ship.
5. If you fill a double bottom tank at sea what difference will it make
to the centre of buoyancy and the transverse metacentric height ?
6. In a vessel of 3000 tons displacement it was found desirable to lower
the existing centre of gravity which was 16 feet above the keel. A'
tank was filled with 260 tons of water, its centre of gravity being
3 feet above the keel. [Required the height of the new centre
of gravity.
Paper 3.
1. What are the advantages and disadvantages of joggled plating?
Illustrate by a sketch.
2. Describe several forms of rivets used in ship construction.
3. How is a watertight bulkhead stiffened and how is it connected to
the shell plating ?
4* Describe the bilge and tank drainage system ot a vessel you have
served in.
654 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
5. Name and sketch the rolled sections used as ship’s beams.
6. A vessel of 1600 tons displacement; centre of buoyancy 8 feet above
the keel; centre of gravity 10 feet above the keel; transverse
metacentre 11*5 feet above the keel Find the angle of heel if a
weight of 8 tons is moved 20 feet across the deck.
7. When and by whom are ships surveyed for re-classification ?
Paper 4.
1. Describe how a stem bar is connected to a flat plate keel.
2. Sketch a stem frame and name its several parts.
3. What are half beams ? How, and to what are their inner ends
connected.
4. Name the components which contribute longitudinal strength to
the ship.
5. Draw a figure to illustrate a vessel in unstable equilibrium.
6. What effect on a ship’s stability has slack water in a double
bottom tank ?
7. What is a stealer ?
Paper 5.
1. What is meant by the “centre of pressure” of a rudder and where
about is it situated?
2. How is the thrust of the propeller communicated to the hull ?
3. Sketch and describe the construction of a cellular double bottom,
4. What are the advantages of having longitudinal bulkheads in cargo
spaces ?
5. Define “coefficient of fineness,” and find ship’s coefficient, having
given, length 400 ft.; breadth 42 ft.; draft 21 ft. in S.W.; dis¬
placement tonnage 7640 tons.
6. Does corrosion take place more rapidly on the inside or outside of a
vessel? Give reasons.
7. Explain how a curve of stability is constructed.
Paper 6.
1. Are solid floors always fitted at every frame in a cellular double
bottom ship ? If not, what is the alternative arrangement ?
2. How are a web frame and a stringer united at their crossings 1
EXAMINATION PAPERS
6£
3. Describe and illustrate by a sketch how a deck flat is made wate
tight at the ship’s side.
4 Illustrate and explain the various methods of connecting the but
in shell plating.
5 What are “ cant ” frames and where and how are they fitted 2
6. A ship’s load displacement is 3420 tons and its C.G is 12 feet abo>
the keel. Oil was consumed during the voyage as follows: 1C
tons C.G. 1*5 feet above the keel, and 80 tons C.G. 6 fed above tl
keel. Find the new centre of gravity. Show also how the initi;
transverse metacentric height will be affected if the transvers
metacentre remains the same.
7. Who assigns the load lines to a ship?
, Paper 7.
1. Distinguish between structural and local stresses as applied to stean
ships. Where are local stresses usually found and what is done t
guard against their effects?
2. Describe a complete transverse member in a ship with ordinary floor
3. Describe how a manhole door is fitted and made watertight.
4. Differentiate between web framing and ordinary framing.
5. What are tie plates and what useful purpose do they serve?
6. (a) Define displacement, deadweight and block coefficient. 0
Define “buoyancy,” “reserve buoyancy,” “centre of buoyancy
and “freeboard.”
7. Ship 2000 tons displacement. A weight of 10 tons is moved 20 fee
transversely across the deck. Find the shift of C.G. If tl
vessel were upright before shifting the weight and she heeled i
find the initial transverse metacentric height.
Paper 8.
1. Show by a sketch how a plated bulwark is fitted.
2. Sketch a main hold ventilator showing the connections to ’twee
deck and lower hold.
3. Describe how decks are strengthened in the way of hatchways i
compensate for the cutting of deck beams.
4. Explain the principal differences between a cellular double bottoi
and a McIntyre tank
686
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
6. What is tipping moment? Define “inch trim moment’ 5 and
longitudinal metacentric height.
6. A ship with a deck load of timber takes a very heavy list, what
steps would you take to make her more seaworthy?
7. A box-shaped vessel floating upright at 7 feet draught is 180 feet
long and 20 feet beam and 10 feet deep. She has no metacentric
height. Find the G.M. when a weight of 40 tons is shifted from
the deck to the bottom of the vessel.
Paper 9.
1. After crossing the North Atlantic, light ship in heavy weather,
where would you particularly look for damage, and why?
2. Describe in detail the fitting and strengthening of shifting boards.
3. (a) What is meant by “breadth moulded,” “depth moulded” and
“length between perpendiculars?” (6) Define “deck sheer,”
“beam camber,” and “tumble home.”
4. (a) State the relative positions of the C.G., C.B., and the metacentre
to obtain stable equilibrium, (b) If a weight is moved across
the deck how does this affect the C.G , C.B. and the metacentre?
5. Define T.P.I., and state where it is generally found. Find the
T.P.I. of a box-shaped vessel 210 feet long by 35 feet beam.
6. Describe the various transverse members in a cellular double bottom.
7. Ship 210 feet long is drawing 10 feet on even keel in salt water.
A weight of 25 tons is moved 30 feet aft. Find the new draughts
assuming the centre of flotation to be amidships and the I.T.M.=
250 foot-tons.
Paper 10
1. What is meant by opening up for survey and at what periodical
intervals are these surveys held? Which survey is the most
important?
2. How are the following tested for watertightness:—Double bottom
tanks, collision bulkheads, hold bulkheads, and decks?
3. Sketch and describe a McIntyre tank.
4. Describe various methods of joining plates together and of connecting
the raised strakes of plating to the frames.
5. (a) Define “righting arm” and “righting moment.” (5) Given the
K.G. of a light ship, how would you find the KG. when loaded?
ID CO
EXAMINATION PAPERS
687
6. Ship 3000 tons displacement is in neutral equilibrium. A weight
of 60 tons is lowered 20 feet into the hold. Find the metacentric
height.
7. A box-shaped vessel is drawing 8 feet on even keel. A weight of
40 tons is moved 36 feet towards the stem. If the I.T.M. is 480 ft.
tons, find the new draughts.
MASTERS.
Ship Construction and Stability.
B.T. Specimen Paper. (3 hours)
1. What are Lloyd’s numerals and how are they obtained ?
2. Sketch in outline a midship section of a ship built with ordinary
floors, naming the various parts.
3. How is continuity of strength provided at the break of a raised
quarterdeck ?
4. What is a 4 ‘joggled plate”? State its advantages and dis¬
advantages.
. What are the main features governing freeboard assignment ?
. What is the efleet of concentrated loads in a ship ? What would
you consider a bad distribution of weight and buoyancy ?
7. A box-shaped vessel 210 feet in length, 32 feet beam, and 16 feet
depth floats on an even keel at draught of 8 feet. The G.M. is 2*8
feet. Calculate new G.M. after placing 64 t tons on deck, vessel
remaining on even keel.
8. A box-shaped vessel of same dimensions as above floats on an even
keel at 8 feet draught. A weight of 50 tons is moved 40 feet forward
in a horizontal direction. Calculate change of trim.
Paper 1.
1. Describe with sketches a plated bulwark.
2. Sketch the rolled sections used in ship construction and state where
they &re frequently introduced.
3. How are the butts of shell plating connected? A butt joint is
“ weeping,” what would you do ?
4. What is an “open survey”? Describe the chief requirements of a
No. 3 survey-
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
5. A ship has a transverse metacentric height of 1*1 foot, and centre of
gravity 12 feet above the keel. 200 tons of water ballast were
taken in, the centre of gravity being 2 feet above the keel. Ship’s
displacement 3500 tons. Find the new metacentric height.
6. What is (a) moulded breadth; (6) moulded depth?
Paper 2.
1. Define Lloyd’s numerals and give their use.
2. Sketch and describe a system of ventilation to a lower hold.
3. Sketch and describe a balanced freeing port.
4. Of what use are transverse bulkheads ?
5. What precautions would you take when pumping up a ballast tank?
6. A vessel of 4500 tons displacement has a G.M. of 2*4 feet. A weight
of 20 tons is moved 24 feet from amidships to one wing. Find the
angle of heel.
Paper 3.
1. Where is the transom floor and how is it fitted ?
2. Describe fully what is meant by a stifl ship,
3. Name the different Classification Societies and state how often ships
are opened for survey.
4. Show by sketches how beams are joined to frames and frames to
floors.
5. How are ballast tanks, bulkheads, and decks tested for water¬
tightness ?
6. A box-shaped vessel 600 feet long is floating at a mean draught of
10 feet forward and aft. If I.T.M. is 240 foot-tons, find the new
draught due to shifting 20 tons aft through 48 feet.
Paper 4.
1. Sketch and describe how a flat plate keel is fitted to a cellular
double bottom.
2. Describe a margin plate and how fitted,
3. What is meant by the terms “tender” and “stiff”! Describe
the condition to produce this in a vessel.
4. Define (a) deadweight; (6) tons per inch immersion.
EXAMINATION PAPERS
689
5. A vessel of 4000 tons displacement has initial transverse G M. of 1*2
foot. 40 tons of cargo was lowered vertically 20 feet into the
lower hold. Find the vessel's new G.M.
Paper 5.
1 Sketch a mast and describe the stepping of a mast in a modern
steamer,
2. Define “buoyancy" and “centre of buoyancy."
3. What is “ hogging" ? Describe a simple method of determining
whether a vessel is hogged or sagged.
4. Describe shifting boards and how they are fitted.
5. What is register tonnage ? Who measures it and for what purpose ?
6. A ship 1800 tons light displacement with C. of G. 10 feet above the
keel loads 3400 tons, the C. of G. of which is 9 feet above the keel
and 400 tons having its C. of G. 16 feet above the keel. Her final
transverse metacentre is 12 feet above the keel. Find her
metaeentric height. %
Paper 6.
1. Describe the stem tube of a single screw steamship and how water
is prevented from entering the ship.
2. Describe how, and when, a curve of metacentres is constructed.
Draw a rough metaeentric curve to illustrate your answer.
3. What minimum number of watertight bulkheads are fitted in a
steamship ?
4. How is the stem of a ship strengthened to withstand pounding
and vibration ?
5. What are the special features of an 4 4 Isherwood " ship ?
6. A vessel’s draught was 17 ft. forward and 16 ft. 8 ins. aft. Her
T.P.I. was 21 tons and her I.T.M. 275 foot-tons. Her No. 5 tank,
* holding 78 tons and 50 feet from amidship, was filled. Find her
new draught.
Paper 7.
1. Show by means of a sketch a transverse bulkhead in a tonnage
opening. What governs the spacing of tonnage openings?
2. What is a hawse pipe? How is it fitted?
690
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
3< Describe how wooden decks are fitted when there are no steel decks.
4. Describe an oxy-acetylene blow-lamp and its uses.
§. Describe and sketch a cellular double bottom with solid floors at
alternate frames.
6. A vessel of 1700 tons displacement having her centre of gravity 17
feet above the keel takes the following cargo on board:—
3600 tons wheat, C.G. 16 ft. above keel.
1000 tons barley C.G. 20 „
100 tons oats C.G. 10 „
What is the height of her centre of gravity when loaded.
Paper 8.
1. What is “synchronism”? How and why should it be avoided?
2. What is the difference between a cellular double bottom and a
McIntyre tank?
3. What is meant by length between perpendiculars, moulded breadth,
moulded depth?
4. Sketch a stem frame and show how it is connected to the hull of the
vessel.
5. (a) What are metacentric curves? (b) Define “metacentric stability.”
6. At the commencement of a voyage a vessel has a displacement of
4500 tons and a K.G. of 11 feet. Initial metacentric height 1 foot.
During the voyage she consumes 150 tons of bunkers from No. 3
hold with a K.G. of 14 feet and 150 tons of water are run into No. 4
tank with a K.G, of 2 feet. Find the metacentric height on
arrival.
Paper 9*
1. How is a mast stepped (a) with a single deck; (&) with two decks?
2. How are the following tested for watertightness:— (a) ballast
tanks; (b) collision bulkheads; (c) decks?
3. Sketch a midship section of a cargo steamer. State the type of
vessel selected, and the system she is built on. Give length,
breadth, depth, also spacing of frames.
£. What is statical stability? What information could you derive from
a curve of stability?
5. Describe how a stem tube is connected in a single screw steamer,
and illustrate by means of sketches.
EXAMINATION PAPERS
691
6 A vessel’s centre of gravity is 8 feet above the centre of buoyancy
and 10 feet above the keel. The transverse metacentre is 11*5
feet above the keel and the ship’s total displacement is 1600 tons.
A weight of 8 tons is moved athwartships 20 feet. Find the angle
of heel.
Paper 10.
1. What is the meaning of the following expressions heard in shipyards
doing repairs:—(a) Chopping; (6) off and fair; (c) fair on?
2 How are rivets in a riveted joint tested? What is the pitch of rivets
in (a) shell plating; (b) margin frame angles; (c) tank reverse angles?
3. What is meant by opening out for survey, and at what periodical
intervals are the surveys extended?
4. Sketch a section through a hatchway and show the connections of
hatchway beams and coamings.
5. Define transverse metacentre and initial transverse metacentric
height. A vessel of 5000 tons displacement, transverse meta-
centre 18 ft. above the keel and centre of gravity 15 8 ft. above
the keel. The vessel is heeled 7°. Find her righting moment.
6. A vessel is 3330 tons displacement, has a draught 17 ft. forward and
16 ft. 6 in. aft. Her T.P.I. is 21 tons and her I.T.M. 275 foot-tons.
Her No. 5 tank, which holds 78 tons, is run up. Find her new draught
if the centre of gravity of the ballast is 50 feet abaft the tipping
centre assumed amidships
ANSWERS.
EXAMINATION PAPERS.
SECOND MATES.
Cargo Work and Elementary Ship Construction,
B.T, Specimen Paper.
3. Draught 22 ft, 5 ins forward; 22 ft. 11 ms aft.
Paper 1.
7. Draught 18 ft 8*7 ins.
8. Load 28 cwt Pull 5 6 cwt., allowing 10 per cent, of load for eacJh sneave
for friction
Paper 2.
3 Draught 14 ft. 8*8 ins. D.W. 1530 tons.
7. GZ at 25° - 1*4 ft. Range 69°.
8. Weight on crane 4 285 tons.
9. Stress 15 1 tons.
Paper 3.
4, Height 18 ft. 4*3 ins.
8, Draught 12 ft. 5 ins. forward; 14 ft. 5 ins. art
Paper 4,
4. 181*55 tons.
6. 85 tons x 12" = 1020 tons.
Paper 5,
6. Pressure 428*5 tons.
7, Change of draught 3*3 ins.
9. Thrust 3*8 tons. Stress 1*9 tons.
Paper 8*
7. 2412 bales.
692
ANSWERS
693
Paper 7.
5. 14 cubic feet
8. 10 cwt.
9 2340 tons at 8 ft. 6 ins.; 4500 tons at 14 ft. 2 ins.; cargo 3400 tons
Paper 6.
5. 38 cub. ft. per ton.
8. 4*93 cwt.
9 15 3 tons at 7 it.; 18 tons at 12 ft ; 18 22 tons at 13 ft.; draught 10 ft
1 5 ins
Paper 9 >
5. 37,695 cases.
9 (a) 2160 tons; (b) 7 ft, 10 ins.
Paper 10
2. £8 12s. lOd. by weight. £9 18s. 5d. by measurement.
8. 100 tons.
9. (a) 11 ft 4 ins.; (6) 17 ft. 00 ins.
Paper 11.
4. 35 cub ft. per ton.
8 2450 tons
9. 13 3 at 5 ft.; 15 4 tons at 7 ft.; 18*3 tons at 13 ft.; draught 6 ft.t 9 ms.
Paper 12
2. 13,266 cases.
7. (a) 11,254; (5) 11,144.
8 90 tons. 4920 tons deadweight.
9. 7 5 ins.
FIRST MATES.
Ship Maintenance, Routine and Cargo Work.
Paper 1.
6. Thrust 8 4 tons. Stress 4 tons
, Paper 2,
5. Hay 1000 tons. Phosphate 2030 tons
7. Loads 6*2 tons, 4*2 tons.
Paper 3.
7. Ore 1960 tons * 29,400 cubic ft.
Grass 1060 tons = 116,600 cubic ft.
8. Tension 2*45 tons on short span, 2*9 tons on long span. Stress at span
connection 2*9 tons.
694
NICHOLLS*S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Paper 4-
6 Consumpt 52 24 tons per day.
7. Thrust 6 1 tons. Tension 5 1 tons.
Paper 5*
3. Jute - 2143 tons » 141,438 cubic ft
Copra - 1357 tons = 108,560 cubic ft.
Manganese 1000 tons — 25,000 cubic ft.
Paper 6.
1. Load 21*5 tons-}-weight of tackle. Pull 6 5 tons.
6. Speed 10’39 knots.
8. Hold No. 1 No. 2 No. 3 No. 4
Capacity 42,500 cu. ft. 52,000cu. ft 50,800 cu. ft. 42,200cu, ft.
Percentage capacity
22* %
27* %
27* 7.
22* 7.
Havre
214
256
256
214
London
202
248
248
202
Hamburg
203
248
248
203
Optional
225
275
275
225
Note —Figure out for each hold its percentage of the total capacity of the
ship, then distribute the cargo for each port on this basis of percentage.
Paper 7.
7. 4*3 cwts. on each leg.
Paper 8.
7. 2409 tons wheat, 961 tons oats.
8. Length 6*7 feet.
Paper 9.
7. 15*5 tons at derrick head. 8*5 tons at the heel.
8. 5*2 cwts. paint.
Paper 10
Hold
No. 1
No. 2
No. 3
No. 4
Capacity
49,700 cu. ft.
51,350 cu. ft.
41,570 cu. ft.
36,580 cu. ft.
Percentage capacity
m %
28} 7 0
m %
m°u
Osaka
250 tons
259
209
182 tons
Optional
277
288
232
203 „
Kobe
166
276
223
104 „
8. Force 3*5 cwts. Stress 2*53 tons.
ANSWERS
695
Ship Construction and Stability*
B.T. Specimen Paper.
7. C. of G. moves up 9 9 inches
6. C. of G 15 feet above keel.
6 Heel 3 C 24'.
5 Coefficient *75.
Paper 2.
Paper 3.
Paper 5.
Paper 6.
6. C. of G 12 47 ft. above keel. GM reduced *47 fi-
Paper 7
7. Shift of C.B. 0*1 ft, G M 0 7 ft.
Paper 8.
7. G.M. % ft
Paper 9*
6. T.P.I. 17-5 tons.
7. 9 ft. 10$ ins. ford.; 10 ft. 1$ ins. aft.
Paper 10*
6. G G. 1 0 4 ft. G.M. 0*4 ft
7* 7 ft. 10$ ins ford.; 8 ft. 1$ ins. aft
MASTERS;
Ship Construction and Stability.
B.T. Specimen Paper.
7. This example is complicated owing to lack of information. It is worked
in six steps as follows:—
(i) To find BM at 8 ft. draught.
Waterline rectangular 210' x 32'.
Transverse moment of inertia = I.
7 r- LB * — 210 x 32 A » 573440 ft.*
12 12
Volume of displacement — V *= 210' X 32' X 8' = 53760 ft.*
BM = — - 573440 = 10-67 ft.
V ~ 63760
696
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
(ii) To find height of C.G. before adding 64 tons.
C B at half draught - - - - KB = 4 00 ft
BU = 10 67
KM = 1467
Given GM — 2 80
C.G. above keel .... KG = 11-87 ft.
(iii) To find rise of C.G due to adding 64 tons at 16 ft. above keel
16 — 11 87 = 4 13 ft.
V 53760
Displacement in tons at 8 ft. draught ~— = 1536 tons
35 35
New displacement = 1536 -f- 64 = 1600 tons.
Rise in ship’s C.G = 6 - 4 , X f 13 = 0'17 it.
1600
.*. KG, — J i-87 + -17 = 12 04 ft.
(iv) To find new BM — B X M X .
(v) New draught.
T.P.I.
LB
210 X 32
35 X 12" ““
Increase of draught =
420
51 =
16
\ New draught 8*33 ft.
= 16 tons.
' = *33 ft.
(vi) New height of metacentre and new GM.
KB X «. 4 17 ft. at half draught.
B X M X = 10-24
KM X = 14*41
KG t = 1204
G % M X = 2*37 ft.
8. The solution of this question requires three steps as follows:*—
(i) To find longitudinal BM.
Longitudinal moment of inertia = I
Longitudinal BM = I~
* V 53,760
BL* _ 32 X 210*
12 12
24,696,000
459$ ft.
(ii) Moment to change trim 1 inch.
I.TJVt. 1636 X 459| ft. 2g0
12 £. 12 x 210 ft. ‘ iw ’
Assuming BM = GM to be a good approximation.
ANSWERS
697
(ui) To find change of trim.
Trimming moment = 50 tons x 40 ft.
= 2000 ft tons
Change of trim = ^^2 = ~i inches by the head.
*o(J
5. New GM 1 6 feet.
6. Heel 2° 33'.
Paper 1.
Paper 2.
Paper 3.
6. Draught 9 ft. 10 ms. forward; 10 ft. 2 ms aft.
5. New GM 1 4 ft.
6. GM 2 18 ft.
Paper 4;
Paper 5s
/Paper 6;
5 Draught 16 ft 8 6 ms. forward, 17 ft. 6 8 ms. alt.
Paper 7.
6. KG. = 16-8 ft.
Paper 8.
6. GM =1 4 ft.
6. 0=3° 49'.
Paper 9
Paper 10. •
5. Moment 1340 foot-tons. ■
6. Draught 16 ft. 8 6 ms ford., 17 ft 4 8 ms. aft.
INDEX,
A
PAGE
A.A.
.. 579
Accidents—
Anchor foul ..
.. 328
Disabled ship
. 329
Engine breakdown
325, 330
Fire
.. 174
Funnel damaged
.. 324
Hatches at sea
.. 323
Man overboard
.. 325
Report of
.. 237
Rudder damaged
326
Steering gear
323, 609
Vessel aground
325, 332
Windlass damaged ..
.. 328
Advance note .
.. 580
Agriculture, Ministry of
.. 539
Air fog signals
.. 247
Allied Signal Manual
.. 631
Allotment note
.. 580
Anchor—
Bower .. 116, 329, 333, 543
Dredging
.. 304
Kedge
.. 298
Lights
.. 192
Mooring
.. 117
Mushroom
.. 119
Patts of
.. 115
Riding at
.. 310
Screw.
.. 118
Sea
114, 119, 331
Shackles
.. 120
Stockless
.. 115
Stoppers
117
Stream
115, 543
Tending ship at
296, 310,313
Testing of
115
Watch
179, 298
Work.
.. 314
Anchors and Cham Cables Act 122, 546
Anchoring and mooring
.. 319
Aneroid barometer
.. 146
Animals (sea transport)
.. 557
Annealing
.. 115
Answers.
.. 692
Antifouling paints 339, 406, 481, 614
Apprentices
.. 572
Areas and volumes
347
Articles of agreement ..
.. 571
Articles, Rule of Road
184, 206
Atmospheric sounders ..
.. 364
Average adjuster
PAGE
.. 581
„ bond ..
.. 582
„ general
.. 581
„ particular
.. 580
B
BB .
.. 582
Balanced ruddeis
.. 466
Ballast tanks .. 438
457, 604
Barnacles
.. 614
Bar keel.
432, 435
Barometer
141, 146
Barograph
146
Barque.
4, 7, 616
Barratry
.. 582
Beacon, wireless
.. 248
Beam—
Deck .. .. 432, 437, 458, 460
Hatch
458, 602
Knees .
437, 450
Panting
.. 460
Berthing ship ..
.. 300
Bells
2, 255
Bends and hitches ..
.. 8-19
Blackwall hitch
14
Bowline
10
Catspaw
17
Camck bend *.
18
Clove hitch
12
Fishermen's bend
14
Half hitches
11
Marline-spike hitch .
16
Midshipman’s hitch ..
15
Mousing
19
Reef knot
17
Rolling hitch
12
Sheet bend
17
Sheepshank
16
Timber hitch
13
Whippings
63
Bending and unbending sail
9
Bilges.
.. 441
Bilge keels
.. 435
,, keelson
.. 435
,, suction pipe
475, 604
Bill of exchange
.. 582
„ health
«. 583
„ lading
.. „ 583
Bitts or bollards
$
.. m
700 NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Bitumastic paints
PAGE
614
Block —
Cargo
28, 564
Clump
26
Coefficient
502
External bound
27
Gin
28. 286
Internal bound
27
Metal
28
Snatch..
27
Board of Trade ..
.. 538
,, ,, Syllabus
.. xin
Boat —
Beaching of ..
.,
78, 97
Beaching signals for
.. 249
Capacity of .
109
Carvel and clincher
.. 103
Construction of
99
Classes of
107
Davits
84
Davit falls
91
Drill .
90, 112, 177
Equipment
105
Gybing
76
Hoisting
90
Launching
83
Lowering
87
Lugsail
66, 71
Management ..
97
Man overboard
77
Motor
92
Markings
no
Names of parts
100
Number of
108
Parts of a
99
Position of
.. 113
Pontoon
107
Rigs
75
Rule of Road
80
Sails
66
Sailing
.66, 82, 268
Sailing terms ..
68
S ea anchor ..
79
Sections
99
Signals
79, 249
At sea . -
e. 91
Tanks ..
.. 107
Tacking
.. 70,73
Titanic
83
Types of
.. 107
Boiler, Scotch ..
.* 166
„ water-tube
.. 1 168
Bolt-rope
63, 611
Bond average ..
.. 582
, „ bottomry ..
.. 585
w respondentia
.. 594
Boot-topping paint
. 481, 814
Bosom piece
.. 446
Boss propeller ..
463, 474
Bower anchor
PAGE
166, 543
Boyle's Law
..
130
Bracket plate
..
. 439
Brails
60
Breast hooks and crutches
461
Breeches buoy
251
Brig
4
British Corporation
542
Brushes, paint
.. 481
Body post
.. 461
Bowline
11
Bull rope
. . 387
Bunker coal
.. 140
Buoyage System
.. 245
Buoyance
361, 503
„ Centre of
503
„ Curve
.. 514
,, Tanks
Bulb angles
107
441, 449
Bulkhead
.. 453
„ Collision
.. 454
,, Doors
.. 155
„ Sluices
154
„ Frames
.. 456
„ Stiffeners
.. 455
Bulkhead, watertight .
454, 456
Bulk cargo
*,
.. 392
Butt joints
• •
445*
Buttock lines
••
.. 541
C
C.C.
« •
.. 585
Cable—
Cham
• •
.. 119
Marking
.,
. > 121
Mooring swivel
..
.. 119
Inspection
,,
.. 121
Laid rope
«*
8
Length
* *
.. 120
Shackles
„,
121
Slips ..
. ,
122
Strength
*,
122
Veering
..
311
Canal dues
*. 550
Caledonian Monarch ,
Plans—
•See Pocket
Camber ..
* ,
402, 433
Cant frames
463
Canvas, rope, sails
62
Capacity plans — See
Pocket
Capstans
. ,
165, 495
Carburetter
94
Cargo work
* *
391, 559
Barrels
«*
.. 400
Bags ,. *,
* *
.. 401
Bales .. # *
*.
401
Bananas
*•
.. 414
Battens „.
* *
.. 390
Capacity
.. 421
Coal „,
*.
392, 402
INDEX
701
Cargo work (cont )—
PAGE
Dangerous .. 172,
405, 477, 540
Deck ..
379, 408
Explosives
172, 402, 540
Frozen
410, 607
Food and fruit
413
Flour ..
400
Gear ..
386, 561
Grain ..
394,401, 406
Hatches
457, 559
Liquid
402, 416
Mineral
. . 404
Mixed ..
.. 399
Oil .
408, 416
Ore ... .. .
392
Plans
420, 518
Preparation ..
391, 398
Questions
398
Railway iron ..
399
Rice
394
Receiving
396, 404, 412
Responsibility
386, 398, 404
Safety precautions .
564
Sections built
597
Spaces
474
Spans ..
269
Special
405
Stowage
395
Stability and trim
515, 519, 530
Stresses
273
Sugar
399
Testing gear
561, 566
Timber
408
Cargo ventilation of
392, 476, 606
Cargo gear—Bull ropes, can
hooks, gins, guys.
nets,
shackles, slings, snotters,
trays ,. 386,
387, 562, 563
Carlings ..
602
Carving note
545
Casualties
577
Cattlemen
558
Cavitation
.. 288
Ceiling.
.. 390
Cellular double bottom
439, 442, 598
Cementing
481, 568, 614
Central Training Board
. . XXI
Centre of buoyancy
503
,, effort ..
268
„ gravity
495, 514, 516
„ pressure
.. 466
„ tipping
520
Certificate —
Anchors and cables .,
115, 543
Cargo lifting gear
561
Crew spaces ..
.. 548
Declaration of health
.. 550
Deratisation ..
553
Grain ..
590
PAGE
Certificate (cont )—
Lifeboatmen . .. - * 548
Life-saving appliances .„ 546
Load line .. .. .. 546
Panama and Suez Canals .. 549
Passenger ship .. . .. 546
Radiotelegraphy .. .. 547
Ship's; register . * .. 545
Certification of ships .. .. 538
Cham strength . .. .. 38
„ hoists . .. .. 47
„ stud link .. .. 119
„ stopper .. .. 33, 117
Charter-party— .. .. 585
Commission .. ,. . . 587
Consignee .. .. *. 588
Demurrage . .. .. 586
Despatch money .. .. 586
Floating clause .. .. 586
Freight clause .. .. 585
Lay days .. . • . ♦ 585
Negligence clause .. .. 586
Penalty clause .. .. 587
Towing clause .. .. 586
Classification societies .. .. 539
Classification surveys .. .. 567
Clear hawse .. .. .. 313
Cleats, hatch .. .. 458, 602
„ stop .. .. .. 465
Coal consumption .. .. ■ 140
Coamings .. .« 458, 602
Code of Signals . .. . 621
Coefficient of fineness . • 373, 502
Cofferdam .. .. 516
Collars' thrust block .. .. 474
Collision—
Avoiding .. .. .. 213
, Bulkhead . . .. .. 454
Diagrams 81, 96, 211, 212, 214, 220,
222, 228, 230, 232, 234
Prevention of .. .. 183
Procedure after .. .. 236
Risk of .210
Compositions, antifouling .. 614
Composition paints .. 481, 613
Conning the ship .. .. 3
Constructive total loss .. 588
Corrosion . .. .. 480
Couple, mechanical .. .. 495
Court of Inquiry .. .. 577
„ Survey . .. 578
„ Naval .. . .. 579
Crankshaft .. .. . • 169
Crew—
Engagement of . . * 571
Advance note . : . 580
Allotment note * .. ( 580
Apprentices ., .. . - 572
♦ Articles of agreement 571, 572
702
Nicholas’s seamanship ant> nautical knowledge
PAGE
Crew (cont)—
Death at sea ..
. . 576
Deserters
574
Distressed British seamen
575
Discharge of
573
Engagement of
571
Failure to join
.. 572
Fines and forfeitures
574
Joining Navy
Officers' certificates ..
575
572
Official log
575
Paying off
573, 574
Period of agreement
.. 574
Seamen left abroad ..
573
Ship abandoned
573
Spaces
.. 547
Crutches and breasthooks
461
Current sailing ..
263
,, wake
.. 287
Cuive of buoyancy
.. 514
,, displacement .
.. 511
„ metacentre
.. 514
,, stability
512
,, tons per inch .
511
Custom House
588, 594
.. cocket card
589
entering and clear-
mg
588
„ papers required at
' * * 588, 589
D
Dangerous cargoes 172, 405, 477, 540
Davits, gravity
85
„ number of
109
„ radial ..
84
„ Welm-Maclachlan
85
Day at sea
2
Day signals for—
Aircraft
2 ay
Cable ship
186
Escorting submarines
.. 239
Examination ship
238
Fishing vessels
189, 243
Mine-sweeping
238
Navigating stern foremost
243
Not under command
186,196
Requiring pilot
188
Steamer under sail only
193
Vessels m distress
253
Wreck marking
.. 246
Deadweight
373
Deadwood
101, 102
Deck appliances
.. 124
Bulkhead doors
155
Docking telegraphs ..
.. 126
Drill, fire and boat ..
177
Engine-room .. ,.
124
Echo sounding
132
Deck appliances (cont)—
Fire appliances
PAGE
175
Lead lines
127
Meteorological instruments
141
Navigation lights sentinel
127
Radio direction finder
152
Soundmg machine
3 29
Steering gear
357, 609
Steam capstan
164
,, winch
164
,, windlass
165
Deck beam
432
Deck camber
402
,, planking .
. 449
,, line
378
Deep tanks
456
Demurrage
586
Density
360, 374
Deratisation
553
Derelict
589
Derricks . 45, 55,
271, 561
,, heavy lifts 44, 45, 46, 388
,, rigging of
45,46
Diagrams—
Buoyage
245
Rule of the Road 211,
220, 222,
Screw race
230, 234
289
Ship's lights ..
195
,, and signals 238,
242, 250
Diaphone fog horn
247
Disbursement
590
Displacement tonnage ..
.. 373
„ volume *.
502
Distress signals
209, 253
Docking and mooring
301
Door in bulkhead
155
Double bottom * ,.
457, 598
Dowels
449
Downton pump
605
Drainage system
441, 474
Draught, change of 272,
373, 374
,, indicator
371
„ marks
377,378
Dredging anchor
.. 406
Dry docking .. JJ3&
430, 613
Dunnage . *
.. 391
Dunstos brake
.. 610
E
Echo sounding machine
132
Edge sight
446, 448
Economical speed
140
Electric navigation lights
257
Engine—
Break down of
325, 330
Cylinders
,* 171
Deck
164, 165
Internal combustion
m
INDEX 70S
PAGE
PAGE
Engine (cont)—
Forces, parallel .
, *
489
Marine motor
93, 171
Fore and afters ..
458, 561
Reciprocating
168
Foundation plate
436
Speed
140
Frames
432, 461, 463
Steam circulation
170
,, cant
463
Steering
159
,, liner
447
Telemotor
160
,, longitudinal
434, 478
Turbine
168
„ reversed
432
Ensign, flying ..
639
„ spacing of
434, 442
Equations—
,, stern
463
Cham
38
,, web
442, 471
Coal consumption
140
Freeboard
480, 404
Stability
525
Freeing ports
605
Strength of rope
34, 38
Freight
584, 585, 589
Equilbnum
496, 501
Frictional resistance
39
Examination papers
667
Fuel consumption
140, 182
„ syllabuses
Xlll, XXI
„ tank gauges
370
Expansion trunk
365
Fulcrum .
. * 489
Fumigation
555
P
Funnel damaged
324
Factor of safety
34
Gr
Factory and Workshops Act
389, 559,
Gangways
554, 559
567
Garboard strake
432, 435
„ gangways
559
Gauge, ram
151
„ hatches
559
,, rope
25
„ lifting gear
561
Gauge tank
367
,, safety precautions
564
Gear, cargo
386, 559
,, testing schedule
566
,, steering
157, 609
Fairing the plans
541
Geometrical figures—Areas and
Fathom w .
127, 343
volumes of barrel,box,circle.
Fid topmast
. . 51, 53
cone, cylinder, pnsm, pyra¬
Fire appliances ..
175
mid, rectangle, ring, sector.
,, chemical extinguishers
173, 176
square, sphere,
triangle,
„ detection
172, 174
wedge ' .
347-349
„ drill and inspection
176
Getting under way
300
„ muster list ..
.. 177
Girders, ship
424
„ precautions
172
Gland, stem tube
470
,, tube boiler
166
Gram certificate
590
Firefoam .. ..
173
Grain feeders . ..
392, 407
Flags
.. 624
,, cargo
392, 401, 406
Flat plate keel ..
436, 441
Graphs and curves
509
Floating clause
586
Graving dock
615
Floating drydock
615
Gravity, centre of
495, 514, 516
Floor .. 432, 438, 440
, 441, 469
Gripe, boat
87
,, transom ..
.. 463
Gross tonnage ..
373, 549
Fog signals
193-204
Grounding
325, 332
Cable ships
193
Gudgeons, rudder
462
Fishing vessels
192
Gun line throwing
253
Fog horns
247, 256
Gun tackle
31
Information re
247
Gunwale bar
606
Not under command
194
Gusset plate
441, 460
Shore stations
247
Gybing ..
.. 69, 76
Steam vessels
193
tr
Submarine
.. 248
XX
Towing,
194
Hatch-
Vessels at anchor
.. 193
Cargo ..
..
.. 457
Wireless signals
.. 248
Beams
•.
458, 559, 602
Wreck marking
.. 246
Cleats • • • •
*.
458
Forces, moment of
.. 488
Coamings
• •
.. 458
704
NICHOLLS’S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Hatch (cont )-—
PAGE
Deep tank
. .. 457
Openings
. . 458
Tarpaulins
402 ,569
Hatches, survey of
595
Hatch sliding beam
560
Hawsers ..
543, 611
Heading? how is she
221
Health, declaration of
550
Health insurance
557
Heaving to
325
Heavy derricks ..
45
Heeling experiment
507
Heel piece
435
Helm orders
3
His Majesty's Stationery Office 539
Hitches
8-19
Hogging.
418
Hold, preparation of 392, 393, 395, 406,
/tn
Hold, pillars
. . 450
Home Office
538, 559
Hose, fire
176
Hound band
49
Housing
53
How is she heading?
221
Hydrometer
359
‘Hydrostatics
359
Hygrometer
151
I
Inch-trim-moment
. .. 523
Indicator of draught
a . 371
Infectious diseases
551
Initial stability ..
505
Inner bottom plating
441
Insurance policy
590
Intercostals
. 435, 440, 469
Internationa] Code of Signals .. 624
„ load lines
376
„ Rules, Preventing
Collision
183-206
Invoice
591
Isherwood ships
478
J
Jack, Pilot
625, 631, 668
Jerquing
Jettison a • • •
591
.. 591
Jetsom ..
a a 591
Joggled plating ..
a a 447
Jury rudder
a a 335
„ steering gear .. 334
K
Kedge anchor ..
. 115,298,328
Keels
.a 435
Keelsons
434, 468
Knees, beam
437, 450
PAGE
Knees, boat
99
Knots —See Bends and Hitches
9-20
L
Landing edge
445, 447
Launch, motor
92
Launching ways
..
543
Lay days
585
Lead line
127
,, cast of
129, 131
Leach
67
Levers
488, 490, 492
Lien
,.
591
Lifeboatmen
548
Life-belts
Ill, 346
Life-boats
107, 346
Life-buoys
106, 110, 346
Lifting gear
561
Light dues
592
Lights —
Identification of
195
Screening of ..
256
Stern
256
Side
256
Masthead
256
Lights to be carried by —
Cable ships
186
Examination vessels
238
Fishing vessels
189
Mme-sweepers
238
Overtaken vessels
192
Pilot vessels ..
188
Sailing ..
187
Steam „
185
Small ,,
187
Towing ,, a.
187
Vessels at anchor
192
„ aground
193
,, not under command
186
„ wreck-marking
,,
246
Lime juice
592
Live-saving apparatus
251
,, penalties ♦ •
113
„ precautions
112
„ rules
113
„ service
249
„ signals
249
Lloyd's Corporation
542
„ agent
»
592
Lightening holes
441
Limbers
432
Line-throwing gun
253
Lloyd's signal stations
553
Load draught *.
373
„ lines . * 373,
376, 378, 380
Load line, assigning
377, 546
„ authorities
, t
377
„ deck cargo . -
a a
378
„ seasons
* .
380
INDEX
705
Load line, tankers
PAGE
380
Log book
340, 382
,, patent
135
,, common
434
,, electrical
128
Long splice
21
Longitudinal framing ..
434, 437
,, bulkheads
.. 456
,, stresses
426
Lookoutman
2
Lower-mast, parts of ..
53
Luff tackle
31
Lugsail ..
67
M
Machinery—
Boiler
.. 166
Compound engine
169
Deck.
'164, 165
Motor engine
93, 171
Steermg engine
159
Triple engine
170
Turbine
168
Magneto ..
94
Management of vessel at anchor 315
Mamfest ..
592
Man overboard .. 77,
Manila rope
94, 297, 320
8, 35, 611
Margin plate
438, 440,599
Marine growths
614
Man-time lien .. . *
592
Marking of ships
372, 377
Matenals, strength of ..
.. 346
Mast and rigging
49, 543
McIntyre tank
436
Mechanical advantage ..
31, 42
Mensuration
.. 343
Merchant Shipping Act
381, 538
Metacentnc height
506, 514, 520
„ diagram ..
514
Meteorological instruments—
Aneroid, barometer,thermo¬
meters, hygrometer, rain
gauge .. .. 144-152
Metric measures and weights .. 345
Millibar.143
Ministry of Agriculture .. 539
„ Health .* 538,550
Moment to change trim . 521
Moment of a force .. .. 488
Mooring .. 117, 264, 297, 319, 554
„ buoy. 118
Mortar and rocket apparatus .. 251
Mortgage . w .. .. 593
Motor boat . 92
„ manoeuvring . 94
* f , engine .. .. „ 93
„ Rule of Road . * 95
Motor ship .. . * «* 171
Mousing
PAGE
19
Muster list
177
Mushroom anchor
119
N
National health insurance
557
Nautical mile
134, 343
Nautophone fog horn ..
248
Naval Court
577
Navigation lights
195
Negligence clause
586
Net tonnage
373, 550
Neutral axis
427
Non-return valve
475
Notices to Manners—
Aircraft at anchor
239
,, m distress ..
239
Air fog signals by bells, dia-
phone, gun, nautophone.
whistle
247
Buoyage system
244
Buoys and beacons ..
246
Closmg of ports
.. 238
Collision with lightvessels
242
General notices
247
Lightvesssls
241
Life-saving service
.. 249
Mine-sweepmg
238
Navigating stem foremost
243
Pilots
241
Salvage of torpedoes
.. 240
Seme net boats
.. 243
Squadrons
239
Submarines ..
239
Submarine cables
.. 243
„ sound signals
Wireless fog signals ..
.. ,248
248
Wreck-marking signals
246
Numerals
482, 542
0
Oertz rudder
.. 467
Officers* certificates
572
Official log
575
Oil cargo
.. 416
„ flash point ..
420
„ on waves
97
„ linseed
.. 480
„ turpentine ..
.. 480
Oscillator submarine signal
248
Ore carrier
393, 430
P
Paint and painting
480, 613
Panting ..
429, 461
Parallelogram of forces—
Action of rudder
m
706
NICHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
PAGE
Parallelogram of lorces (coni )—
Canal boat
263
Cargo spans
269
Current sailing
263
Derricks
271
.Moorings
.,
264
Sail propulsion
268
True and apparent wind .. 266
Parbuckling
402
Parcelling
Partners' mast ..
49, 612
602
Penalties relating to—
Boat drill
113
Life-saving appliances
113
Collision
236, 242
Reporting accidents
237
Gram cargoes
408
Load lines
373, 377, 383
Not showing ensign
... 551
Penalty clause C/P
587
Pilot
241, 593
Pillars
434, 450
Pintles . .
465
Pipe lines
419, 441,474
Pipe sounding ..
475
Piston
171
Plating, shell
446
„ deck
, .. 447
Plan cargo
420
Planking boat .
103
„ deck ,.
... 449
Plans, shear, body, half breadth 541
Pneumercator .
368
Poop fittings
158
Poppets or cradle
..
544
Portage bill
..
593
Port Authorities
..
539, 550
Port Sanitary Authority
553
Post, propeller .
461
,, *rudder
464
Power of purchases
.. 31, 41
Preparing for sea
294
Pressure of water
365
Promissory note
593
Proof strength ..
..
346, 566
Propeller—
Action of
287
Bossing
463, 474
Bush
328
Cavitation
287
Race
289
Shaft
472, 473
Slip
140
Speed .
139
Steering effect
290
Strut
474
Thrust
288
To unship
328, 472
Propelling machinery
166
Protecting detunes B/L
PAGE
584
Protest .
593
Pumps .. . 416,474,602
Pulleys .
28
Purchase—
Advantage of
31, 39, 44
Diffeiential
47
Equations
42, 346
Friction
39
Gun tackle
42
Handy billy
43
Luff tackle
43
Single, double, treble
.. 31. 41
Spanish burton
32
Watch tackle
43
Q
Quadrant rudder .. 158, 334, 609
Quarter
2
Questions on—
Accidents
322
Anchoring and mooring 9
.. 319
Anchor work .
.. 314
Anchors and cables .
.. 122
Boat lowering
9
„ construction
.. 103
„ drill
87
,, equipment
Cargo .
105
422, 424
Cargo and trim
527
Collision regulations ..
.. 215
Deck appliances
.. 180
Docking and berthing
.. 402
Fire emergency
172
Fog signals
.. 204
Getting underway
305
Heaving off .
.. 332
How is she heading?
.. 225
Hydrostatics .
♦ . 383
Life-saving appliances
110
Motor boat
93
Notices to Mariners ..
.. 259
Parallelogram of forces
277
Rigging and sails
65
Rope and wire puichases
48
Lights
184
Mensuration .
355
Ship construction
.. 483
,, handling
.. 294
Ship log books
.. 340
„ stability
.. 59?
E
Racking ., .. ,*
.. 429
Radio direction finder ..
.. 152
Raft construction • *
339
Rain gauge
.. 151
Ratline .. .. „,
.. 612
Rats .. „ * • ♦
.. 563
ikj)ex 707
Receiver of wreck
PAGE
594
Reciprocating engines
168
Red lead
480, 613
Reef
74
Refrigeration of cargoes
410, 414, 609
Register certificate
545, 594
Register tonnage
373, 549
Registration of ships
538, 545
Regulations, Examination xm
„ sea service
. . XX
„ collision ..
183
Relief valves
168, 171
Relieving tackle
609
Reports of accidents
237
Rescuing a crew
339
Respondentia bond
594
Reversed frames ' .
432
Rider plabe
433, 434
Rigging of steamships
. 49-65
Righting levers
504
Rivets and riveting
444
Risk of collision
.. 210
River work and berthing
- 303
Rockets
249, 251, 254
Rope—
Bolt.
63, 611
Canvas and sails
62
Knotting
10
Preservation of
612
Splicing
20
Strength of
34
Wire ..
36
Rdpe preservation
612
Jtudder—
Action of
264, 291
Balanced .. ..
.. 466
Bearing pintle
465
Brake
158, 610
Centre of pressure
466
Coupling
465
Damaged
326, 327, 334
Gudgeons
.. 462
Jury.
.. 335
Single plate ..
464
Spade .
466
Stops .
465
Streamline
.. 467
S
Safe working loads
35, 38, 346
Sagging.
.. 427
Sails—
Bending
63
Parts of
61
Propulsion by
.. 268
Reefing
74
Setting and furling ..
57-60
Sheet.
57
Spanker
60
Sails (cont)—
PAGE
Staysail
.. 59
Tack
.. 57
Trysail
57
Sailing ship types
4, 616
Salvage
595
Salvage of torpedoes
240
Scantling
482, 542
Schooner
4
Scotch boiler
166
Screemng of lights
256
Screw aperture . .
463
Screw race
287, 289
Screw twin
293
Scuppers
437
Sea anchor
331
Sea service qualifications
. . XX
Section-built
597
Section, transverse
432
Seme net fishing
243
Senior officer's duties ..
322
Sentinel navigation lights
127
Sending topmasts up and
down 51, 54
Serving ..
49, 612
Shackles ..
120
Shaft coupling ..
472
Shaft tail end
472
Sheaves
26
Sheepshank
16
Sheet
57
Ship construction
426
Areas and volumes ..
350, 516
Ballast tank ..
f .. 438
Bar keels
435
Beams
432
Beam knees ..
450
Breasthook
.. 461
Built sections
597
Butts
445, 480
Bulkheads
453
Camber
402, 433
Caulking
449
Cellular double bottom
439, 598
Centre keelson
434
Chock angles .
600
Decks
447
Deck planking
449
„ bolts
.. 449
Deep tank
456, 603
Diamond plate
443, 661
Floors .. .. 432,
438, 440, 469
Frames* . 432, -
161, 463, 478
Girder ship .
426
Keels and keelsons ..
435
Landing shell
445
Longitudinal framing
434, 437, 478
Pillars
438, 450
Plating
446
Planking . * ..
.. 449
708
NICHOLLS’s SEAMANSHIP AMD NAUTICAL KNOWLEDGE
Ship construction (cont)—
PAGE
Rivets, riveting
Rudders
Sagging and hogging
Scantlings
Sheer strake ..
Shell plating ..
Sluices
Sole piece
Sounding pipes
Stability-
Stealers
Steam circulation
Stern frame ..
„ tube
„ post
Strakes, shell plating
Stringers
Stringer plate
Stresses, various
Transverse flaming ..
Watertight bulkhead
„ flats
Web frame
Ship handling
Docking and berthing
Disabled
Getting under way .
Management at anchor
Manoeuvring
Man overboard
River work
Tending at anchor .,
Shipping office papers ..
Shrouds
444
444
427
482
433
446
154
462
475
501, 503,
525
448
,,
170
..
462
. ,
462
462
433,
446
436, 443,
559
437,
604
426
-431
. ,
432
454,
456
452,
601
443,
600
. ,
294
. ,
302
. .
329
305
310
*292,
295
325
„.
301
296,
310
571,
588
49,
543
Signalling—
Alphabet flag ., .. 622
Catechism .. .. .. 660
Courses and bearings signals 628
Distress signals ,. .. 657
Gale warning signals .. 658
Geographical signals 623, 638
General code signals ., 637
International Code signals .. 621
Latitude and longitude signals 626
Morse alphabet .. ., 643
„ how to signal .. 647
„ exercises .. .. 649
„ by radio .. ,. 659
>, by sound .. 655
Numeral signals. 624
Pilot signals.658
Pilot Jack signals .. .. 631
Quarantine signals .. .. 656
Semaphore signals .. .. 640
Ship's letters ..632
Single letter hoists .. 625, 636
Substitutes, use of ♦, *. 622
Time signals , * ,, ,, 627
Signalling (cont)—
PAQ
Towing signals
63
Simpson's Rules
35
Slings
277, 38
Slip of propeller
14
Slipping cable
31
Sloop
Sluices
.. 15
Snatch block
2
Snubbing round
32
Sounding machines
128, 13
Sounding pipes
.. 47
Spanish burton .
3
Spanish windlass
f
• * A
Spanker
(
Specific gravity
360, 3(
Speed and fuel ..
14
Splice, eye
2<
„ grommet
25
long
21
short
?C
„ wire
23, 563
Sprocket chain .
47
Stability and calculations
403, 501, 525
Stability calculations ..
503-5: 0
Standing orders
.. 178
Stays
49, 543
Steam circulation
170
Steamship types
5
Steamship, Rule of the Road 214
Steering chains
618, 158
„ emergency gear
164, 315, 609
„ hand gear
157
„ engines
159, 570
„ telemotor
.. 161
„ turning circles
266, 293
,, rules
206,210,215
Stern framing .
.. 463
„ tube .
,, 472
„ cruiser
466
Stiff ship
403, 506
Stowage of cargo
386-421
Stowage factors
.. 347
Stop valves
,, 418
Stops, rudder
465
Strakes of plating
433, 446
Stream anchor
135, 543
Strength of cargo gear
346, 481, 561
Strength of material ..
.. 346
Stresses .,
426
Strum box
804
Struts.
.. 473
Strum or rose box *.
398/604
Submarine boll
.. 248
Submarine cable , *
.. 243
„ escort y *
239
», signals
.. 248,
Summer tanks ,.
385, 417,478
Summer load line
.. 878
INDEX
709
Survey—
PAGE
Court of Survey
.. 578
Classification .
567
Of cargo
.. 595
Of hatches
595
Of vessels
595
Of crew spaces
547
Machinery
570
Steering engine
570
Tanks ..
570
T
Table wire rope
37
Tack
57
Tackles, various
.. 31-41
Tati shaft
472
Tank deep
456
Sounding *
475
Tanks—
Gauge
367
McIntyre
. 438
Side
438
Testing
.. 364
Tankers—
Air valves
419
Cofferdam
416
Expansion trunk
416
Eire precautions
420
Flash point oil
420
Heating coils .
.. 418
Xsherwood system
.. 478
Pipe lines
.. 419
Pump room
416
Steam valves
418
Summer tanks
357, 407, 478
Trunk
478
Ullage
365, 418
Tarpaulin
402, 569
Tender ship
403, 506
Telegraphs •
124
Telemotor
.. 160
Temperature, standard
.. 360
Tending ship at anchor
310
Testing material
121, 566
Thermometers
147-150
Thermotank ventilation
476
Thrust block
.. 474
Tide, effect of ..
.. 311
Tide rode
.. 296
Tiller ’.
3, 609
Timber load line
.. 379
„ deck cargo
408
Tipping centre
.. 520
Tons per inch
510
Tonnage, gross, net
373, 502, 549
Toredo worm
614
Torpedo, salvage of
.. 240
Topmast fitted ..
53
w telescopic
51
Towing ..
PAGE
329, 336
Towing clause C/P
586
Transom frame .
463
Transverse section
432, 478
„ thrust
288
Trestle-trees
54
Trim
519
Trunk, ship
393, 416
Trysail
.. 57, 63
Tube, boiler
168
,, sounding .. .. ^
Turbine
366
168
Turbme circle ..
266, 293
„ centre
265
Twin screws
293, 473
Types of ships ..
.. 4, 5
U
Ullage.
365, 418
Unstable equilibrium ..
505
Upper deck
.. 437
Uptake m boilers
166
V
Valves, tank air «. .. 419
„ stop .. .. 418,475
Veering cable .. . 311
Vehicle paint . .. .. 480
Ventilation of ship 172, 392, 395, 476,
606
Volumes and surface areas of
box-shaped bodies, cylinders
and wedges.. . .. 349
Volume of displacement .. 502 f
Vernier .. .. . „ 143
W
Water pressure
Watertight flats
„ bulkheads
„ doors
Wake current
Warranties
Wash ports
Waterplanes
Watches at sea
Weather tide
Weighing anchor
Weights and measures—Troy,
avoirdupois, lineal, survey¬
ors', square, cubic, liquid,
dry, time, angular, metric,
miscellaneous ship measures
Wetted surface equation
Web frames
Weeping butts
Wheel and axle
Whippings v *.
. 363
452, 601
454
155
287
. • 591.
.. 605
541
3
296
507
343
481
442, 478
482, 815
494
»
710 ‘ , , NJCHOLLS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE
Whistles
PAGE
255
Winches and capstan ..
164
Windlass
165
Windlass damaged
328
Wind and tide
312
Wind rode
296
Wind, true and apparent
266
Winging out weights . .
403
Winter load line
378
Wire, care of
36
„ gauge
25
„ grip
25
,, sections
25
„ T . . ^AGE
Wire, Splicing .. ., 22-24, 563
„ strength .. .. . . gg
Wireless bearing .. . , 154
Wireless fog signal .. . . 248
Wood decks .. .. .. 449
Y
York-Antwerp Rules .. . . rjg j
Yard, signal .. .. , . 52
Z
Zones, seasonal .. . „ ,. 3 go
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