Full text of "The design and construction of power workboats"

See other formats

UC-NRLF

r uuo I ^

||l||!WI|||l||ii|l|l|!i|i!||

C 5 b7S ab2

!!;:■.•..«
|-.-.i

i!!:''

imre

liiili

THE DESIGN AND CONSTRUCTION
OF POWER WORKBOATS

By ARTHUR F. JOHNSON. N. A.

)!! llllltl !

i i

P'tl
! iiii;

I r
liHIiiliii i I

! ii

III I II 1

liiilii

ilr

iiliiil

:ii iHiiiiii!^

iiililii"

Bn«»n'

«eTi>i»

iV-'"'-'

Tke
Design ana Construction

-^ of

Power Workboats

Arthur F. Johnson, N. A.

and

Entered at Stationers' Hall, London

1990

By The Penton PublisKing Company
Cleveland, Ohio. U. S. A.

All

RigKts Reserved l)#/)i

Library

iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiimiinuiiiniiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiuiiniiiiiiiniiiiiiiiiiiiiiiiiiiiie

NaVal architecture as applied to power worl^-
hoats lacks literature; perhaps because bigger game
is more absorbing. When it is realized that the
future inland waterways of this country must be
developed and utilized; also that power boats will
provide the means of avoiding the repetition of
lamentable inefficiency in conveying the products
of our interior to the principal ports or centers of
distribution, proper design will be no small factor
in the solution of the problem.

4S5333

2IIIIIIIIIIIIIIIIIIIII II H

Digitized by the Internet Archive

in 2008 with funding from

IVIicrosoft Corporation

http://www.archive.org/details/designconstructiOOjohnrich

I Table of Contents

Chapter I — Advantages and Classifications 1

Chapter II — Analyzing Operating Conditions 5

Chapter III — Buoyancy, Draft and Displacement 9

Chapter IV — Laying Down and Fairing the Lines 15

Chapter V — Stem, Keel and Stern Design 19

Chapter VI — Application of Steel Construction 25

Chapter VII — Wood and Steel Transverse Framing 29

Chapter VIII — Design of Longitudinal Framing 33

Chapter IX — Bulkheads Demand Careful Planning 37

Chapter ^— Hull Planks— Fenders— Bilge Keels 43

Chapter XI — Decks for Wood and Steel Boats 47

Chapter XII — Constructing the Deck House 53

Chapter XIII — Companions — Hatches — Awnings 59

Chapter XIV — Mats — Davits — Winches — Windlasses 65

Chapter XV — Anchors — Towing — Deck Drainage 71

Chapter XVI — Auxiliary Machinery and Quarters 75

Chapter XVII — Food Storage, Heating and Lighting 79

Chapter XVIII — Painting Structure and Sheathing 83

Chapter XIX — How Concrete Power Boats Are Built 87

Appendix I — Tables of Scantlings for Power Workboats 93

Appendix II — Designs and Details of Typical Power Workboats 101

:iiuiiiiiiiiiiiiiiiiiiiiiiiiiliiiiiiliiiliiiiiliitniiniiiiiiiiint(i»tiiwwiiiiiiiiiiiiiiiiiiiiiiiliiiliiiiiiiiiiiiiiiiiiiiii^ iiiiiiiiiiiiiii:iiiiiiiiii:iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii!iiiniiiiuMiiiiiiiiiiiiiiiiiiiiiiiiiniiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii^

List of Illustrations

Page |

Fig. 1 — Cost Chart ok Power Vessels Under Normal Building Conditions (Commercial) 5 |

Fig. 2 — Cost Chart of Large Power Vessels (Commercial) Under Normal Building Conditions 6 |

Fig. 3 — Character Curves Sternwheel Power Boats (Wood) Less Than 100 Feet Long 6 |

Fig. 4 — Hull Proportions Sternwheel Power Vessels Over 100 Feet Long 7 |

Fig. 5 — Hull Proportions Power Tugs Over 60 Feet Long 7 j

Fig. 6 — Character Curves Power Lighters 8 |

Fig. 7 — Hull Proportions Small Screw Vessels (Wood) 8 |

Fig. 8 — Shows Water Pressure Acting on a Floating Vessel 10 j

Fig. 9 — Illustrates Relation Between Draft and Displacement 11 |

Fig. 10 — Indicates the Utility of Reserve Buoyancy 11 j

Fig. 11 — How External Force Causes Heeled-Over Position 12 |

Fig. 12 — Path of Water Around a Box-Shaped Hull 12 |

Fig. 13 — -Gradual Stream-Line of a Properly Formed Vessel 12 |

Fig. 14 — Lines of a SO-Foot Power Tug 14 |

Fig. is — Various Forms of Stems IS |

Fig. 16 — Various Types of Sterns 16 |

Fig. 17 — Sterns for Sh.\li.ow Draft Vessels 17 |

Fig. 18 — Paddle Wheel Stern 17 |

Fig. 19 — Illustrating a Typical Body Section 18 |

Fig. 20 — Stem of a Wooden Tug 19 j

Fig. 21 — Stem of a Small Power Workboat 19 |

Fig. 22 — Stem of a Large Vessel 250 Feet Long 19 |

Fig. 23 — Stem of a Large Wooden Vessel 20 |

Fig. 24 — Construction of Spoon Bow for Shallow Draft Bo.\ts 20 |

Fig. 25 — Clipper Stem of Auxiliary Sailing Vessel 20 |

Fig. 26— Construction- ok Bottom Girder of Large Wooden Ship 20 |

Fig. 26a — How Keel Bolts are Countersunk 21 |

Fig. 27 — Keel of a Wooden Schooner 21 |

Fig. 28 — Keel of a Wooden Tug 21 |

Fig. 29 — Keel of a SO-Foot Workboat 21 |

Fig. 30 — Keel of Shallow Draft Vessel 21 1

Fig. 31 — Overhung Transom Stern of Auxiliary Schooner 22 I

Fig. 32 — Stern of Tug or Lighter With Single Deck and Guard Timber 22 |

Fig. 33 — Transom Stern for Small Boat With Metal Rudder 22 |

Fig. 34 — Compromise Sterns Seldom Used on Workboats 22 I

Fig. 35 — Shallow Draft Stern With Stern Wheel 23 |

Fig. 36 — Longitudinal Section of Wooden Tunnel Stern Boat 23 |

Fig. 37 — Cross Sections Showing Different Tunnel Construction 23 |

Fig. 38^Bar Stems and Method of Scarphing 2S |

Fig. 39 — Three Types of Keels of Steel Vessels 25 |

Fig. 40 — Methods of Fitting Keelsons 25 |

F"ig. 41 — Center Keelson with Innercostal Plate 26 I

Fig. 42 — ^Transverse Section of Double Bottom 26 I

Fig. 43 — Construction of Overhung Transom Stern 26 |

Fig. 44 — Attaching Guards and Rails 26 I

Fig. 45 — Construction of Rudders and Strut Bearings 27 |

Fig. 46 — Elevation and Plan ok Sternwheel Vessel 27 |

Fig. 47 — How the Bottom Plating is Dished for Tunnel Stern 27 |

Fig. 48 — Stern (Or Bow) of Double Ended Steel Ferry Boat 27 |

Fig. 49 — Construction for Tugs and Power Lighters 29 |

Fig. 50 — Transverse Framing of Large Wooden Vessels 30 |

Fig. 51 — Frames for Shallow Draft Vessels 30 |

Fig. 52 — Midship Section of Steel Tug or Lighter 30 |

Fig. 53 — Where the Main Deck Overhangs the Hull 31 |

P"iG. 54 — Shallow Draft Vessels Have Straight Frames 31 |

Fig. 55 — Steel Stanchions and Stanchion Heads 32 |

Fig. 56— Longitudinal Stringers and Shelves For Wooden Tugs; Frames for Shallow Steel Vessels 33 |

Fig. 57 — Cross Sections Showing Frame Construction 34 |

^lUiiuuiumiiumaiiwniniimiiiwiMwiiuuiiiuuujiiiiiiiiMwittiuiiuwiiuijiiiijiiuiiiiiwinwiuu iiiiniiiiiiiiiiiuiiiiiiiiii iiuiiiiiiiiiiiiiimiii iiuiiijiiiiiiiiiiiiii iiiiiiuuiiiiuiiiuiiiijmuuiii iiijiiiiiiiiiiiiiiiiii iiiiiiiiiiiiiiiili?

List of Illustrations

Page

Fig. 5S — Steei, Side Keef-sons with Transverse Frami.nx 35

I Fig. 59 — Haic it and Cockpit Coami ng Construction 35

Fig. 60 — Cross Section of a Tug with Longitudinal Framing 36

I Fig. 61 — What Happens When the Bow or Stern Compartment is Flooded 38

I Fig. 62 — Transverse Watertight Bulkhead of Wooden Vessel Longer Than 125 Feet 38 |

I Fig. 63 — Transverse Watertight Bulkhead for Small Wooden Vessel 39 |

I Fig. 64 — Cross Sections of Various Minor Bulkheads for Cabins, Etc 39 |

I Fig. 65 — .Steel Bulkheads and Fastenings for Wooden Vessels 40 |

I Fig. 66 — Shows Method of Fitting "Shoes" at Bulkheads Where Keelsons and Stringers are Cut 40 |

I Fig. 67 — Construction of Tank Bulkheads for Oil and Water; Also Metal Bulkheads for Minor Com- I

I PARTMENTS 41 |

I Fig. 68 — How Stealer Plates ari: Introduced 43 |

I Fig. 68-a — Methods of Fitting Hull Plating to Frames ; 44 |

I Fig. 69 — Construction of Fenders and Bilge Keels 45 i

I Fig. 70 — How Decks are Classified 45 |

I Fig. 71 — Drawings Showing Contour of Decks and Sheer 4g |

I Fig. 72 — Methods of Laying Deck Planks 48 |

I Fig. 7.3 — Cross-Section of Wooden Deck Construction 49 j

I Fig. 74 — Construction of Decks of Steel Vessels 50 |

I Fig. 75 — Construction of Ceilings and Double Bottoms 50 |

1 Fig. 76 — Contour and Construction of Wooden Deck Houses 54 |

I Fig. n — Construction Details of Steel Houses 55 |

j Fig. 78 — Watertight Doors, Air Ports and Dead Ligh f s 56 1

I Fig. 79 — Construction of Hinged Windows a.xd Skvlights 57 |

1 Fig. 80 — Wood and Steel Companions 59 |

I Fig. 81 — Detail Construction of Companion Slides and Hatches 60 |

I Fig. 82 — Watertight Hatches and Manholes 61 I

I Fig. 83 — Construction Details of Ladders and Kails 62 i

I Fig. 84 — Awning Stanchions and Fittings 63 1

I Fig. 85 — How Pole Mast and Boom is Fitted 65 |

I Fig. 86 — Construction and Install.mion of Steel Masts, Also Boom Crotch 66 I

j Fig. 87 — Davits and How They are Installed 67 I

I F'lG. 88 — Winches, Windlasses and Ground Tackle 68 I

Fig. 89 — Anchors, Chocks and Hawse Pipes 72 |

Fig. 90 — Towing Bitts and Knees ■]■>, |

Fig. 91 — Chocks and Cleats 73 |

Fig. 92 — -Fuel or Water Tanks, Flat Side Type 75 |

Fig. 93 — Installation and Equipment of Fuel Tanks 76 |

Detail of Inlet Connection for Pipe Suctions from Sea 76 1

Detail of Soil Pipe Discharge Connection 77 1

Detail of Scupper from Tiled Toilet Space 77 |

I Fig. 95 — Built-in Refrigerator in Cabin Trunk of 50 to 75-Foot Power Boat 7g |

I Fig. 96 — Construction of Refrigerator Door 79 |

I Fig. 97 — Interior of Stack with Tanks 80 |

1 Fig. 98 — Ventilating Equipment gO |

I Fig. 99 — Ventilating Equipment 80 I

I Fig. 100 — Pipe and Transom Berths 81 |

I Fig. 101 — Bilge Keels and Sheathing 84 1

I Fig. 102 — How Wood Sheathing is Fitted on Wooden Hulls 85 1

■ Fig. 103 — Typical Section o.'^ a Concrete Hull Under Constructiu.\- 88 |

I Fig. 104 — Metal Clips Used to Support Longitudinal Rods 89 i

I Fig. 105 — Method Used in Holding Rods in Place for Pourixc; Forms 89 =

I Fig. 106 — Molded Guide Bar Punched to Receive Rods. This is a Very Satisfactory Method Used with |

I Excellent Results 89 I

I Fig. 107 — Construction of Stanchions and Girders 90 |

1 Figs. 108 and 109 — Bow and Stern Construction for a Concrete Workbjat 90 1

I Fig. 110 — Details for Attaching Miscellaneous Fittings 91 |

1 §
^lWlllltMllUluuMlUll«wlllUlllllllmlmwMWllllllllllllllllllllllllnll1UlllllllllllllNllllllHll^

Arthur F. Jihnson, N. A., authcr cf De-
sign and Cunslraciion 0/ Power Wcrl^boots,
apptars here in the unikrm of AssislanI Marine
Superintendent of the U. S. Army Transport
Seroiez. Besides being educated as a natal
architect and marine engineer, h: has had wide
experience in th: U. S. Engineer's Department
and in shipbuilding yards and as Designing
Engineer for the Fabricated Ship Corporation,
Milwaukee, Wis., so that h; has a practical as
well as a theoretical knowledge of the subject.
Mr. Johnson, at thz present writing is Produc-
tion Manager of Nelson Purchasing Organiza-
tion, Chicago, III.

liiniiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiniiiiiiiiiiiiiiiiiiliiiniiiiiiiiiuiiiiiiiiiiiiiiiiiiiiiii iiiiiiiHiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiif

CHAPTER I

Advantages ana Classincations

^^^^^HE utilization of vessels, propelled by internal
M C^\ combustion engines, for commercial transporta-
^ J tion by water is no longer in the experimental

^^^ stage; nor has there been a dearth of literature
setting forth the general characteristics of the numerous
uses to which this type of craft has been adapted. From the
very first, good engineering portended success of this class of
vessels, since there can be no sounder logic than that

points should be understood by owners, operators and
builders.

In general power workboats may be classified under
three main headings: First, service in which engaged;
second, material of which constructed; and third, type
and arrangement of propelling machinery.

With respect to service, the first consideration is
whether the waters navigated are to be "open" or

chemical energy as contained in fuel will produce maxi- "sheltered;" that is, whether the vessel is to go to sea

mum power when converted into mechanical energy at
the nearest practicable location to the point of applica-
tion of the power.

Whereas, in steam-propelled craft, the latent energy
in fuel was first converted into heat of gases due to
combustion, these gases
then transmitting their
heat to water in a
boiler, generating steam ;
this in turn passing to
the engine, losing con-
siderable heat content
en route ; in a combus-
tion engine all the en-
ergy conversion takes
place in the cylinders.
This not only results
in saving of weight by
omission of boilers and
increased space for car-
go storage due to lesser
space occupied per
horsepower, but also the
abolition of heat losses
and the carriage of wa-
ter for boiler feed.

These advantages
were at first oflfsct by
practical defects in com-
bustion engine design,
lack of skill on the part
of the operators and the
customary conservative
frame of mind on the
part of vessel owners
which is inevitable to
all radical innovations

or to operate in rivers and harbors.

Seagoing vessels to date have been mainly cargo car-
riers (wooden or steel) or auxiliary sailing craft. The
construction in these being identical with that of steamers,
has been thoroughly treated in other works of ship

design.

V e s s e Is traversing
coastwise, harbor or
inland waters are
those here to be dis-
cussed and embraced'

(1) Ferries:

(a) Fast passenger.

(b) Passenger and
freight.

(2) Tugs.

(3) Power lighters.

(4) Tank boats:

(a) Water.

(b) Petroleum prod-
ucts.

(5) Trawlers.

(6) Shop boats:
(a) Repair boats:

(Machine shops)
(Welding plants)

(7) Pumping and
wrecking boats.

Passenger ferries vary
from fine-lined relative-
ly fast vessels of from
50 or 60 feet, to 200
feet in length. Depend-
ing upon the length of
run they may vary in
speed from 10 to 20

KUMTUX, LUMBER TOW BOAT

She is 65 feet x 16 feet and is powered with a 110-horsepower Standard-Corliss

engine. She is owned by the Puget Sound Tow Boat Co. and has given her

owners great service

miles (statute). Their characteristic arrangement is to afford
maximum passenger accommodation : Sleeping, mess accom-
modations and sanitation for the large craft on long runs
(seldom more than for one night) ; and maximum seating,
sanitary and sometimes messing provisions for relatively short
Since power boats, particularly those using the lighter runs not exceeding one day (sunrise to sunset).
fuels, have practically replaced the small steamers of fore-

in industry. The tendency to let others pay for the experi-
ments incidental to practical perfection delayed progress in
development.

Power Boats Have Replaced Small Steamers

gone days, and the ones requiring considerable power
and cheap fuel have long since shown the dcsiral)ility of
diesel engines ; effort should be made to co-ordinate the
valuable experience of operators and record the features
of design in power boats. This is particularly desirable
with respect to the smaller vessels, where ordinary power-
boat construction would prove fragile and the essential

Jitney Boat for Commuters

A recent innovation in this connection has been the
"jitney boat", making runs from points within an hour's
run of a city or railroad depot, and used for transporting
commuters.

Passenger and freight ferries of moderate speed (8 to
12 miles), relatively full lines and ranging in length

The Design and Construction of Power Work Boats

welding. With the prevailing prices
at present, and as long as steel ex-
ceeds $0.03 per pound, this would not
be desirable, however.

Composite vessels arc those with
wooden hull planking and steel framing.
For boats under 100 feet long, this
is scarcely a desirable construction,
though in larger ones it is being ex-

from 50 to 200 feet are becoming in-
creasingly popular as sources of profit.
The holds and main deck are employed
for freight storage and the superstruc-
ture houses the passengers. A cargo
boom forward facilitates lifting heavy
weights, the hoisting winch being geared
from the main engine or being an inde-
pendent machine. There is a single-
ended type for voyages of more than tensively employed.

one-half hour or so ; the ones for short Wooden construction is the most
and frequent trips as well as the car universally employed and desirable for
ferries being double-ended. They may vessels less than 100 feet long. This
be propelled by screws or paddle wheels, is due to the facility in working the
Tugs comprise probably the most nu- material, simplicity of equipment needed
merous class of the commercial power in building yards and also to the fact
boats. Their lengths are from 35 to that vessels up to this size are amply
150 feet and speeds (when not towing) strong when built of wood. Steel, if too
from 8 to 12 miles. Many of the con- light, has not the requisite stiffness and
ventionalities in tug design could be corrodes through quickly. If the steel
improved or dispensed with to the ulti- is made heavier, care must be taken
mate betterment of the whole. This that the vessel is not of greater dis-
will be elaborated upon subsequently, placement than would be the case in a
The essential to a tug's success
is great pulling power at slow
speeds, requiring a heavy-duty,
slow-turning engine coupled to a
propeller of large diameter and
low pitch ratio (0.9 to 1). Power
lighters are modified types with
large decks and hold space for
cargo and a boom for loading.
Tank boats, as their name iin-
plies, carry water or petroleum
in bulk, the form being full and
the engines aft (at the stern).
Trawlers are of tug design, fit-
ted with hoisting booms and
fish tanks. They attained no-
toriety in the recent war by
their utility in mine sweeping.
Shop boats, carrying machine
shop tools, welding plants and
apparatus are becoming numer-
ous. They are constructed with
a view to bringing the repair

equipment to the disabled plant, in- wooden one of corresponding size and
stead of requiring the cripple to visit strength.

'*. --^^ ^j ^fli^r- •*_;^ i

_.*l

it_^._ —

-^ ■ ]

ir,\,,.,., , .-CnOONER CONSTANCE
One of the finest boats ever built for halibut service-
measures 87 feet on deck, 18 feet beam and carries
horsepower Standard-Frisco engine

the shipyard. Workboats used for salv-
ing and wrecking purposes carry a mis-
cellaneous equipment, such as pumping
apparatus and machines for handling
divers. With the value of vessel prop-
erty going up sky high these boats are
becotning profitable.

Steel Too High for Small Boats

By material of construction is ineant
that of which the prmcipal strength
members and hull are composed. Steel
is most universally einployed in vessels
over 100 feet long, though it has been
used in pressed form for small power
and life boats. In the writer's opinion
powerboats as small as SO feet long, pro-
viding they are full lined, could -be built
of light galvanized steel shapes and
plates, riveting being replaced by spot

Power workboats of wood are much
more substantially built than are pleas-
ure craft and it is to establish stand-
ards and details in these practical ves-
sels that this Avork is undertaken.

Reinforced concrete promises to be-
come extensively used in boat construc-
tion, particularly where a considerable
number of the same form and size
of vessels are produced. It is no longer
an experimental construction, barges and
seagoing vessels now building being the
result of observing, for years, those
already in service.

Concrete Boats for Inland IVatcrways

Steel and concrete having nearly the
same coefficients of expansion and the
fact that painting, copper sheathing and
fouling of bottoms will be troubles of

the past as well as that deterioration
is negligible, point to extensive utilization
of this desirable material, particularly
for inland waterways. A very rich
mixture (1-1-^-3) of concrete, with
gravel passing J-^-inch mesh, is used
for the hull. This is molded or "shot"
onto galvanized wire mesh supported
by ordinary reinforcing rods, the to-
tal hull thickness varying from 2 to
5 inches. Internal hull structure em-
bodies reinforcing steel skeleton
work with a leaner concrete (1-2-4) or
(1-3-5) again using fine gravel. The
density of concrete determines its
life, strength and watertightness as
well as its elasticity. Ordinary con-
crete, as commonly used ashore,
would not prove satisfactory for ves-
sels. If the ships are molded, stand-
ard metal molds may serve for nu-
merous hulls, but if one or two only
are to be built, the "gunning" meth-
od is more desirable, particularly
in view of the fact that a more
nearly ship-shape form can be
built in this manner. Molded
hulls have resulted in crude-
ness of lines and while this is
immaterial at low speeds, tugs
or finer craft would require
excessive power unless more
refined in form. The type and
arrangement of the propelling
machinery together with the
means of converting the power
generated into propulsive thrust
will not be elaborated upon
except wherein they affect hull
construction or arrangement.
The power plant itself may be
combustion engines of any one
of the following types :

(a) Diesel or oil engines, op-
erating on two-stroke or
four-stroke cycle using
heavy oil fuel (between
14 degrees and 23 de-
grees B a u m e), wherein fuel
is i n j e c ted as spray into
the cylinders with compressed
air and ignition results from
high compression of the charge.
Revolution ISO to 300.

"Semidiescl" — or heavy distillate
engines, using kerosene or dis-
tillate fuel with hot bulb igni-
tion or spark. These engines
are similar to ordinary gasoline
machines, but operate at slow
speed and are much more heav-
ily constructed. Revolutions from
200 to 600.

Gasoline engines (usually four-
stroke cycle) using light pe-
troleum distillate, with electrical
ignition, low compression and
operating (in heavy marine work)

-She
140

(b)

(c)

Advantages and Classifications

between 350 and 800 revolutions

per minute,
(d) Gas producer plants using coal,

wood or other gaseous fuel.
Diesel or oil engines being relatively
high powered, are not much used in
small commercial power boats. An in-
teresting departure from this generality
is the government tug Manteo which
has a 100-horscpower, 2-cycle, dicsel en-
gine and which is only 50 feet long.

"Semidiescl" engines, a rather vague
and incorrect term, are excellent for
heavy duty service providing the oper-
ator understands them. Such engines
should be more extensively utilized than
they now are, not only because of the
saving in fuel, but their rugged con-
struction and ability to run continuously
if properly attended. There have been
some sad experiences, however, when
inexpertly handled.

Gasoline, or light distillate engines,
of heavy duty design, are usually direct
connected to the propeller and are the
most generally employed. Sometimes,
in order to conserve space and weight,
small, high-speed engines (900 to 1200
revolutions per minute) are installed
with a reduction gear to the propeller
shaft. This system is comparatively re-
cent in ships, though long used in auto-
mobiles. It promises to become pop-

ular if light fuels do not attain pro-
hibitive prices.

Gas producer plants have never been
extensively employed, though when prop-
erly designed and operated they have
proved practical and economical. They
consist of a producer proper, where fuel
is caused to give off its combustible
gases through distillation, partial com-
bustion and sometimes chemical combina-
tion with water vapor.

The fuels used may be wood, coal
of a low grade or residue combustible
material. The gases generally pass through
a "scrubber" where foreign matter is
removed by spray or other means and
thence to an internal combustion engine.

The arguments against producer plants
are : Excess weight and space occupied
by the plant, and skill necessary to
proper operation.

The propulsive mechanism of com-
mercial power boats may be propellers
or paddle wheels.

Propellers are most commonly em-
ployed where light draft is not a factor
in design. This is because of their pro-
tected location with respect to the hull,
which minimizes damage by striking
against docks, towed vessels or by rough
seas. Another reason is that higher
revolutions with efficient propulsion ren-
der them adaptable to direct coupling

with engine shafts, with attendant re-
duction in space occupied by machinery
of a given power.

Paddle wheels (at side or stern of
vessels) are desirable in shoal water
because of efficient propulsion under
limited depth of immersion and also fa-
cility of repairing buckets damaged
through striking submerged olistacles.

The practical range of revolutions in
paddle wheels is between 20 and 40,
rendering necessary a reduction in speed
from engine to wheel. This is accom-
plished through belts, gears, chains, or
a combination of these.

Profcllcrs in Tunnel Boats

Propellers in tunnels, so that the wa-
ter surface at rest is not more than
one-third of the wheel diameter below
the upper tip of blades, are frequently
employed for shallow draft propulsion.
Though the wheel diameter is restricted
and revolutions comparatively high, ex-
cellent results have been obtained in
this way, even in tow boats. In these,
the out-of-the-way propellers present
an advantage over the projecting paddle
wheels, and the lightened and less roomy
machinery afford lighter draft on a
given size of vessel or permit of de-
crease in vessel dimensions for given
draft and power.

The Design and Construction of Pozvcr Work Boats

CHAPTER II

Analyzing Operating Conditions

"^^^^^HE first essential in selecting
m (7\ a design of power boat is a
^ J careful study of the require-
^^^^ ments imposed by the service
in which it will be engaged.
This will determine the general arrange-
ment, degree of equipment, power,
amount of fuel, stores and water, ma-
terial and construction, etc.

It is assumed that one undertaking
the construction of a commercial vessel
will familiarize himself with these re-
quirements by careful study of the local
conditions at the terminals and through
the trade route which the vessel is to
ply. Conditions are so varied and the
combinations of these so numerous that
exhaustive discussion would scarcely be
warranted.

In general the factors encountered are :

(1) Character of service.

(2) Character of materials ported.

(3) Conditions of water traversed.

(4) Terminal adaptation to the trade

contemplated.

The design as affected by character
of service has already been considered,
as have the general features called for
in passenger traffic.

Freight may be roughly subdivided
into :

(a) Fast package.

(b) Perishable.

slow.

(d) Bulk.
The first of these

has heretofore been
most extensive on
ocean or large in-
1 a n d or sea trade
routes, services in
which natural con-
ditions have pro-
hibited land trans-
portation. There is
reason to suppose
that with reliable
and well adminis-
trated inland water-
way runs, much of
this revenue earn-
ing cargo could be
diverted from the
none too punctual
rail routes of this
country. This does
not infer competi-
tion, but rather co-
operation with the
railroads, since

many water routes are shorter between
terminal points and the question of
collection and delivery may afifect to-
tal time in transit and portage charges.
Fast water freight would work well in
conjunction with passenger traffic. It is
not very many years gone that travelers
preferred canals to stage coach and the
analogy still applies insofar as comfort
and restful conditions in water travel
surpass those in a sleeping car. It is
merely a question of providing every
convenience and shortening time in
transit which are not insurmountable
difficulties in many overnight runs.

Kinds of Freight Handled

Perishable freight is of two general
kinds : That which will deteriorate due
to delay in shipment (mainly edibles) ;
and that which must be protected from
the weather. The first of these will
require refrigeration or ventilation, and
the second merely storage in holds or
under cover. Both of these classes are
readily adaptable to economical water
conveyence, delay at terminals being the
most adverse condition to be remedied.

Miscellaneous slow freight already
constitutes a considerable percentage of
the total transport material in some

sections of this country and a greater
proportion in many foreign lands than
is generally supposed. It consists of
many items in variegated sizes from
large pieces of machinery to small boxes,
cases, castings, etc.

Bulk freight lends itself most agree-
ably to storage and terminal loading
and discharge. It consists of coal,
brick, petroleum, ore, grain, etc., and
renders possible the design of vessels
specially fitted to carry the particular
commodity. Maritime traffic in this
class is also profitable and constaiith
increasing in volume. Freight affects
hull design in conjunction with the
route of travel, necessitating large closed
holds or 1)eing most expeditiously stowed
on deck in the open or under cover.
The amount to be carried per voyage is
dependent upon length of the trip (in
distance as well as duration). If the dis-
tance is considerable, the decreased num-
ber of trips will necessitate a larger
ship that profit may result. On a short
run the assumption that gross expense
of conveyance is inversely proportional
to tonnage conveyed, does not necessarily
hold, since the increased time for load-
ing and discharging may be excessive
when considering the loss in vessel's
earning power while
idle and the great-
er original invest-
ment. Again, the
depth, width and
contour of channel,
dimensions of locks,
wharves and man-
euvering space at
terminals may be
considerations af-
fectinjc size, pro-
portions and even
propelling mechan-
ism of the vessel.
Thus a compara-
tively narrow and
shallow river with
sharp bends, locks,
and sometimes rap-
ids, would necessi-
tate radically differ-
ent design from
that permissible
with a wide, deep
and open stream.
Paddle v.'heel or
tunnel-sterned boats
with shallow beamy
hulls have arisen

The Design and Construction of t'oivcr Work Boats

from the first mentioned natural limila-
tions, whereas the normally formed
screw vessel is desirable where these ob-
stacles are absent or negligible.

How to Determine First Cost

When the appropriate type and its
lengths have been decided upon, it be-
comes necessary to determine the prob-
able first cost and also the other
dimensions properly applicable. The ideal
condition with respect to funds would
be that in which these were ample for
the most desirable type of vessel. Very
often this is not the case, and modifica-
tions in design must be resorted to.

If the total costs of numerous vessels
in a class are plotted as ordinates upon
abscissa representing vessels' lengths,
it will be found that all the resulting
spots lie within an area enclosed by two
curves, which are the maximum and
minimum amounts requisite for building
this type of vessel for any length.

Figs. 1 and 2 are "cost charts" of
this nature, the smaller vessels having
cost ordinates to large scale in Fig. 1,
while the larger vessels' prices are
modified to suit the limits of Fig. 2.

It will be observed that the screw
vessels in Fig. 1 are more costly than
the shallow draft paddle vessels. This
is because of the more complex form
and rugged structure of the former,
requiring more elaborate and carefu!
workmanship to withstand the strain?
of rougher waters which are navigated
by this class. The same reasoning ap-
plies to Fig. 2, where it will be further
noted that steel vessels are most ex-
pensive in cither class.

The excess first cost of this material
is more than offset by the gain in
strength, durability and carrying ca-
pacity, for contrary to general supposi-
tion, the total weight of a wood vessel
is greater than that of a steel one hav-
ing equal strength, while the interior
volume of the wooden one, representing
cargo capacity on given dimensions, is
also less than that in the steel hull.

The costs here plotted represent re-
sults of competitive bids during normal

times, contracts having been awarded
not necessarily to the lowest, but rather
to the most responsible bidder, as deter-
mined by capital and equipment of the
boat yard.

If a certain fund is available for the
construction of power boats, the vari-
ous sizes of a given type could be
derived as follows : Assume that the
amount at hand is $40,000. Then in
Fig. 1, an 82-foot wooden screw tug
could be built to maximum equipment
standards and two 87- footers of simplest
character in normal times. At present
the costs would be higher — the above
sum affording a vessel about 70 feet
long, with all refinements and two 40-
footers which would be little beyond
hull, engine and steering gear.

On the other hand, if a vessel of
given length is to be built, its cost
range could be similarly arrived at.
In Fig. 1, a 60-foot tug (wooden)
would range between $7500 and $23,750.
The maximum figures are most nearly
in accord with present mean rates for
ordinary boats.

Beam Varies on Given Length

For a given length of vessel, the
beam (width) and the depth may vary
considerably. This variation is limited
in the case of beam, by its effect upon
stability and speed for a given power.
Also to complicate matters, where the
increased beam heightens the tendency
to resist capsizing force, it will result
in greater resistance to propulsion.

The degree to which stability may be
sacrificed to minimizing resistance has
been determined within minimum and

Analyzing Operating Condition!;

maximum limits, beyond which it is
rarely and with questionable gain, that
proportions are assigned in design.

These proportions are graphically de-
picted in Figs. 3 to 7, and dimensions
for any length selected from these can-
not fail to produce vessels of ample
strength, stability and reasonably speedy
in proportion to the power installed.

The depth of hull at mid-length is
an index to strength, just as the depth
of a girder determines ability to resist
deflection. A deeper vessel on given
length is relatively stronger than a
shallow one.

Power of the engine to drive the hull
whose dimensions have been selected,
is the next consideration. Too many
vessels, particularly in the "small boat"
class, have either too much or too little
energy in the machines driving them,
for a vessel may be over as well as
under-powered. It is fallacious to pre-
sume corresponding increase in speed
for additional horsepower.

Further, it is impossible to calculate
the exact resistance of a given sized
boat by direct mathematical analysis.
This is because, even with two vessels
having like dimensions and diplacement,
the hull forms may vary considerably.

There is at present no precise mathe-
matical formula for that peculiarly
warped surface of a hull, and until this
is established (which will only be after
years of investigation) the only ways
to properly predetermine engines, are :

(a) By comparison of results in other
similar vessels.

(b) By actually towing a model of
the vessel, to scale, and deriving the

result through the "method of com-
parison".

The first of these methods is that
most feasible in power workboat de-
sign ; the second, though in large ves-
sels usually more reliable, is too elabor-
ate and occasionally does not produce
results anticipated, particularly in un-
usual forms. Since it is impossible to
install machinery to scale in the model,
or to fit miniature propellers, thereto,
considerable experience is necessary to

foretell the energy dissipated between
engine and the point of expenditure of
propulsive thrust. Adding to this the
cost of a series of models, also the ex-
pense of conducting the tests at a
properly equipped model testing basin,
the method does not at present justify
its adoption for small commercial boats.

In these, allaround working qualities
are often superlative to minimum resist-
ance at given speed, so that unless
predecessors of like proportions have
proven uneconomical, the result of ob-
serving their features (favorable or not)
will ordinarily produce excellent re-
sults.

To this end, Figs. 3 to 7 have been
elaborated, embracing powers, displace-
ments, drafts and speeds of various
types. These are characteristics of
many boats in each class and may be
considered representative.

Working Out the Details

Assume that the vessel is to be an
80-foot stern wheel towboat of wood.
In Fig. 3, we would derive the follow-
ing limits for particulars of the hull
by reading up to the various curves as
ordinate on the abscissa labeled 80:

Length, 80 feet.

Beam, between 16 feet and 20 feet
6 inches.

Depth of hull, 32>^ inches and 51
inches.

Draft in running condition, 17 inches

and 25J4 inches.
Displacement (fresh water), between

31 tons and 73 tons.

The Design and Cunstniction of Poivcr Work Boats

Brake-horsepower of engine, 37 to 62. derived from the remaining charts if
Speed (per hour) 6 to 10 miles. other types of vessels are under consid-

These preliminary figures may be eration. It should be understood that

the lowest horsepower is the one which
will drive the narrowest hull at the
minimum speed, the higher power in
the narrower boat will probably produce
the maximum speed figure, while in
the beamier boat this power will result
in a speed intermediate between maxi-
mum and minimum.

The next consideration is that of fuel
capacity, the kind having been predeter-
mined by considerations of economy,
facility of replenishing, etc., in the
locality of the vessels' route. Gasoline
and light distillate engines will require
about a pint of fuel per horsepower
per hour. This figure is high for a
fuel consumption test with the engine
on the blocks at the factory, but it must
be understood the ordinary working
conditions in the boat will prove less
economical, due to wear, leakage, occa-
sional overheating and perhaps neg-
lect. It is therefore imperative to antici-
pate these difficulties by providing fuel
ample under worst conditions.

Fuel oil for diesel engines will be
safely estimated at 0.7 lb. per horse-
power per hour.

In our chosen vessel, at 62 horse-
power, burning gasoline or distillate,
that many pints or 7j4 gallons would
carry the wider boat eight miles and
the narrower one ten. From this the
tank capacity could be determined, de-
pending upon facility of re-fueling. If
the home dock were capable of re-filling
tanks (a desirable feature) less fuel
need be carried with increase in amount
of freight. It should not be necessary
to re-fuel oftener than once per work-
ing day, and, of course, if the voyage
required more time than this, once per
trip, if feasible.

The general arrangement will be gov-
erned by type. Accommodations for
crew need only be fitted if these can-
not return to their home port nightly,
in which case necessary plumbing, lock-
ers, etc., must also be installed. A study
of arrangement will later be made, it
being sufficient for any type to assume
a somewhat similar layout to other
boats in the same class, many of which
have been ably described by current
magazine contributions.

The preliminary study of and deci-
sions with respect to design have now
been gone over, bringing us to the stage
at which details must be understood
and perfected.

CHAPTER III

Buoyancy, Draft and Displacement

'^^^^^^HE first requirement which
m (t\ commercial vessels must have
^ 1 is the ability to float. By
^^^ this we mean that they should
be suspended on the water's surface
and that a certain portion of the hull
should be above that surface. Now
if the total weight of a boat be divid-
ed by its total watertight volume in
cubic feet, the resulting figure is the
pounds per cubic foot or the "density"
of the vessel. If this weight per unit
of volume is greater than that of a
cubic foot of water, the vessel will
sink.

Fresh water has a weight of 62.5
pounds per cubic foot, while salt wa-
ter weighs 64 pounds for an equal
volume. A cubic foot of solid iron
weighs 490 pounds and would sink
in fresh or salt water. A cubic foot

of wood which weighs from 30 to 60
pounds will float in water. If a
cubical box, 1 foot on each side, were
made of steel sheets J4 inch thick
the six plates forming the sides would
weigh 10 pounds each, making a total
weight for the box of 60 pounds. This
60 pounds is the density of the box
and since it is less than the weight
of a cubic foot of either salt or
fresh water, the steel box will float.

In fresh water we could put a load
of 2 pounds in the 60-pound steel box
and it would still float. In salt water
this load could be iYz pounds.

We thus see that the difference be-
tween the total weight of a floating
body and the weight of an equal
volume of water represents the cargo
carrying capacity and that the same

vessel will carry more cargo in salt
than in fresh water.

Experiment on Flotation

Take a shallow tray and weigh it
carefully. Then place a deep bowl
in the tray and fill the bowl brim
full of water, taking care that it is
just on the point of overflowing into
the tray but that none of the water
gets into the tray. Now weigh a
square block of wood which is about
half as wide as the bowl. Place the
block carefully on the water in the
bowl. The block will float in the
bowl and some of the water will over-
flow into the tray. Take the block
carefully out of the bowl and lift the
bowl from the tray, being sure that
no more water spills. Then weigh
the tray again with the water which

SCANDIA, SEA-GOING POWER HALIBUT BOAT OF THE TACIFIC COAST

The Design and Coiisfructioii of Power Work Boats

was displaced from the bowl by the
floating block.

Deducting the original weight of
the dry tray from the final weight
of the tray with displaced water
will give the actual weight of the
water. It will develop that the water
displaced will weigh exactly what
the block did.

We therefore see that the weight
of a floating body is exactly equal to
the weight of water it sets aside or
displaces.

Now imagine that while the block
floated in the bowl, we had frozen
the water in the bowl. Then if the
block were removed a cavity would
remain in the ice and this cavity
would have exactly the shape and
volume of that part of the block
below the water level. The shape
of this cavity is called the "under-
water surface" of the floating body.

If the water which overflowed into
the tray were pourad back into the
cavity in the ice it would be filled
and no water would remain in the
tray.

This proves that: "The volume of
water displaced by a ship is exactly

First the form of hull is carefully
drawn and its volume is calculated to
diflferent heights above the bottom of
the keel. When the volume to each
level or "water plane" has been
formed, determine the weight of an
equal volume of the water in which
the vessel is to float by multiply-
ing the number of cubic feet in the
hull to each water level by the weight
of a cubic foot of water.

In general the ton is used for dis^
placement weights in preference to
the pound, that the figures employed
may not be too large. To convert
cubic feet of hull volume to the
number of long tons (2240 pounds)
of water displaced by that volume,
divide by 35 for salt or 36 for fresh
water. This is based on the fact that
one ton of fresh water equals 35 and
of salt water equals 36 cubic feet.

Suppose that a chart is made where-
on heights above a given base line
represent draft to scale. On the base
line we can represent displacement
in tons or in cubic feet by a hori-
zontal scale measuring from left to
right. Then if our calculations at
2 feet draft had shown the vessel's

8 X 10

X 75 = 41.67 cubic feet

144

FIG. 8-SHOWS WATER PRESSURE ACTING ON A FLOATING VESSEL

equal to that part of the ship below underwater volume to be equal to 10
the waterline," and that: "The weight tons of displaced water we could in-

of the water displaced by a ship
equals the ship's weight."

This displaced water is the "dis-
placement" of the ship and may be
expressed in cubic feet or pounds.

Hold a body of known weight at
arm's length and let go of it. The
body falls to the ground. This shows
that if any mass is suspended and

dicate this displacement by a point
on the chart 2 feet above the base
and 10 tons to the right of the ver-
tical line through zero. A similar
point for the displacement corre-
sponding to each level for which the
hull volume has been calculated would
show just how the weight of dis-

not prevented from falling it will placed water increased as the vessel
answer the attraction of gravity. sank to diflferent water levels. A

Now fix a spring scale to .the body curve through these spots is known

and again hold it out. The pull on
the scale shows the body's weight.
Therefore, to prevent a body from
falling, the force holding it up must
equal the body's weight.

A body floating is subject to the
same "pull" of gravity, but is prevented
from falling, or rather "sinking" by
an upward force in the water called
"buoyancy", whose magnitude equals

as the displacement curve, one of
which has been drawn in Fig. 14.

Getting the Weight of the Lumber

After the complete plans showing
the vessel's construction and the loca-
tion of each item therein have been
drawn, it is possible to calculate the
weight of every item and of the struc-
the ship's weight and also that of the ture. For example the keel may be
displaced water. a timber of oak 75 feet long and 8

The foregoing principles are applied inches wide by 10 inches deep. The
in determining to just what level a volume of this timber in cubic feet
ship will float and the method of is obtained by multiplying the cross
doing this follows: sectional area by the length.

Oak weighs about 54 pounds per
cubic foot when saturated with water
and allowing for fastenings. There-
fore the keel of the vessel would
weigh:

41.67 X 54 = 2250.18 pounds or
slightly more than one long ton.

Performing a similar calculation for
the other framing, the hull planking,
the deck beams and planking, the
bulkheads, deck houses, tank and
engine foundations, masts, booms,
deck fittings, life boats, furniture and
joiner work, machinery, tanks, steer-
ing gear, etc., we obtain the com-
plete hull weight in pounds. Divid-
ing this sum by 2240 gives the tons
for the vessel's light displacement.
If the holds are calculated full of
the cargo which is to be carried and
the water and fuel in the tanks are
added to this, the sum of these three
figures is the total deadweight of
cargo which may be added to the
light displacement thus getting the
full load weight or displacement of
the vessel.

Now on the base line of the dis-
placement curve find the figure cor-
responding to the light displacement
in tons. Draw a vertical line from
this point to the curve. Then at
the point where this vertical line cuts
the curve, draw a horizontal line over
to the scale showing draft. The figure so
found will be the light draft of the
vessel and a similar procedure with
the load displacement will indicate
the full load draft.

After the vessel is built the dis-
placement scale is useful in finding
the weight of cargo carried per trip.
This is done by taking the vessel's
light displacement in tons from the
load displacement as obtained from
the curve by reading the tons corre-
sponding to the draft with cargo
on board. The diflference gives the
long tons of cargo.

An Illustration of Buoyancy

Fig. 8 shows the water pressures
acting on a floating vessel. These
may be divided into horizontal and
vertical forces and are shown by
arrows. The horizontal forces on
the sides are equal and opposite at
each depth below the surface and
therefore balance each other so that
there is no tendency to move side-
wise, "d" is the draft in feet and
the upward pressures on each square
foot of the bottom equal "d" times
the weight of a cubic foot of water.
The sum of all such upward pres-
sures equals the force "buoyancy"
which keeps the vessel afloat.

Buoyancy, Draft and Displacement

Fig. 9 illustrates the relation be-
tween draft and displacement with
and without cargo. When the vessel
is light, "d" is the draft, "DC" the
water line and the rectangle "D C E F"
a cross section of the hull below wa-
ter. "C B" is the center of gravity of
the displaced volume and is called the
"center of buoyancy". The upward
force of the water is assumed to be
concentrated at this point.

When cargo is placed aboard, the
vessel's weight increases and the
force of buoyancy acting in the light
condition is not sufficient to support
it. The vessel, therefore, sinks to
the new water level "A B" where
buoyancy as represented by the in-
creased weight of displaced water
becomes equal to the augmented
weight of the vessel, "d' " is the new
draft and "C B'" the new center of
buoyancy.

The height "f" of the deck above
the water line is called the "free-
board". It is a measure of the weight
which can be added to completely
submerge the vessel by increasing the
displacement by the volume "H K A
B". This volume is called the "re-
serve buoyancy" and is necessary for
stability and safety against sinkage.

What is Meant by Reserve Buoyancy

In Fig. 10 the utility of reserve
buoyancy is indicated. Assume that
the box-shaped vessel has two walls
or "bulkheads" (G M and FN) divid-
ing it into three compartments, and
that the vessel floats at the water
line W L. Suppose that a hole is
made in the bottom of the central
compartment so that sea water enters
between the bulkheads. Before this
occurred the volume of the hull (B
CFG) between these bulkheads dis-
placed a certain amount of water and
thus helped to float the vessel or
rather to support as much of the total
vessel's weight as would equal the
water displaced. When water en-
tered the compartment the section
between the bulkheads no longer af-
forded buoyancy since the volume of
sea water originally displaced rushed
back into the cavity. Meanwhile the
vessel's weight has not changed and
since this weight exceeds the net
amount of intact buoyancy represent-
ed by the displaced volumes A B G H
plus C D E F, the vessel will sink
until the weight of water displaced
again equals the original amount.
This sinkage is assumed to the water
line W L'. During the sinkage the
water rose freely inside the damaged
compartment to the level M N and no
buoyancy could therefore be regained
in that compartment.

FIG. 9— ILLUSTR.'\TES RELATION' BETWEEN DKAFT AND DISPLACEMENT

When sinkage has ceased, the vol-
ume L M G H plus the volume N P
F E equals the original volume A D
E II, and since by taking B C F G
from A D E H we get the same vol-
umes as by taking L M B A and
N P D C from the sum of L M G H
and N P E F, we see that the added
end displacements LMBA plus NP
DC must equal B CFG.

Figuring Reduced Freeboard

Notice that the original freeboard
"I" has been reduced to "{'". This
reduced freeboard is easy to calculate
in the case of a box. For example
assume that the vessel in Fig. 10 is
100 feet long, 30 feet wide and 10
feet deep. Suppose the bulkheads
G M and FN to be at a distance of
40 feet from each end, or that the
distance between them (B C) is 20
feet. If the draft (A H) is 5 feet
before the bottom is punctured, what
will be the new draft after the acci-
dent to the central compartment?
First calculate the volume of the orig-
inal displacement

A D E H = 100 X 30 X 5 cubic
feet = 15,000.
15,000

Then — • = 428 4/7 tons of salt

35
water or
15,000
:= 416 2/3 tons of fresh water.

Then when G F is punctured the
lost volume of displacement is B C F
G = 20 X 30 X 5 = 3000 cubic feet.

Therefore the amount of original
displacement remaining is
15,000 — 3000 = 12,000 cubic feet =
ABGH plus CDEF.

The lost 3000 cubic feet must be
replaced by volumes LMBA plus
N P D C which are each 40 feet
long and 30 feet wide but whose

heights L.'\ arc not known.

Volume LMBA = 40 X 30 X
(LA) feet; volume NPDC = 40
X 30 X (LA) feet.

Volume LMBA = 1200 X (LA)
feet; volume N P D C = 1200 X (L A)
feet.

LMBA + NPDC = 2 X 1200
X LA feet = 2400 X LA' = 3000
cubic feet.

3000

LA ^ =: 114 feet which is

2400
the amount the vessel will sink. The
new draft is 5 plus \]4 = 6j4 feet.

The Value of Transverse Bulkheads

The foregoing shows the value of
transverse bulkheads and also makes
it clear that the volume above the
original water line W L and outside
of the damaged compartment (B C
G F) must be greater than the lost
buoyancy (B C G F), for unless this
can be regained in the undamaged
ends, the sinkage (L A) will be great-
er than the freeboard and the vessel
will not float after the accident.

When some external force inclines
a boat the conditions which exist in
the heeled-over position are shown in
Fig. 11. The water line when up-
right was at W L and the displace-
ment volume had the rectangular
cross section R A S T. Point B is
the center of buoyancy when upright
and point G the center of gravity
of the vessel and its contents. W' L'
is the new water line when heeled
over and it crosses the original water
line at point O.

An Analysis of Stability

Observe that the cross section
N D S T of the underwater bedy has
been changed to the form of a trape-
zoid, whose center of gravity is at
B'. This point is therefore the center

.^'l l

. .n

p 'i m'l'

"' ivi.

D i W L

;

i -1

1 1

FIG. 10— INDICATES THE UTILITY OF RESERVE BUOYANCY

The Design and Constnicfion of Power Work Boats

i-r;. 11— how external iouce causes heeled-over position

of buoyancy when heeled over and
we see that a change in the form of
a vessel's underwater body causes a
shift of the center of buoyancy.

Now the force of buoyancy acts
vertically upward through B' and is
equal to the vessel's weight acting
downward through G, which point is
not changed in position. The two
parallel forces are a distance of G Z
apart and are called a "couple". They
tend to rotate the vessel in a direction
opposite to the motion of a clock's
hands, or "counter clockwise", which
in Fig. 11 tends to return the vessel
to the upright. The magnitude of
this couple equals one of the forces
times the lever arm "G Z". Let W
equal the vessel's weight (also the
buoyancy or displacement in pounds
or tons). GZ is in feet so when
W multiplies it we have:

'jV>

I El

F1(J. 12— PATH UE WAIER ARUUNU A
BOX-SHAPED HULL

W X GZ = the foot pounds tend-
ing to turn the vessel upright.

This product is called the moment
of "statical stability".

It will be noticed that the force of
buoyancy intersects the vessel's cen-
ter line at the point M which is called
the "metacenter". The distance G M
is the "metacentric height" and is a
direct measure of the distance G Z.
GZ

( = sine of angle GMZ)

FIG. 13— GRADUAL STREAM-LINE OF A
PROPERLY FORMED VESSEL

If M is above G the vessel tends
to right itself and G M is called posi-

tive. When M is below G the couple
is reverse in direction and would
upset the vessel. G M is then called
negative. This unstable condition can
exist if the point G is high up such
as with very heavy deck loads.

The method of calculating stability
is too complicated for discussion in
this article, but can be obtained by
consulting Attwood's work on "Theo-
retical Naval Architecture".

The box-shaped vessels we have
thus far considered would carry a
maximum amount of cargo with given
limiting dimensions of length, beam
and draft. Ease of propulsion plays,
however, an important part in con-
tributing toward earning capacity.

Resistance of the Movixg Hull

Figs. 12 and 13 illustrate the eflfect
of hull form upon the resistance set
up by the water when a vessel moves
through it.

Looking down on a box-shaped
moving boat, the arrows in Fig. 12 are
the paths taken by particles of water
which are deflected when the boat
passes them. Notice the sharp right
angle turn or sudden changes in
direction of the particles' flow. These
paths of flow are called "stream-
lines". The sharp changes in direc-
tion cause eddies at the two forward
corners of the box form and also at
the after portion.

Experience has shown that all
changes in direction of streamlines
should be gradual as in Fig. 13 and
that a vessel properly formed will
offset the loss in carrying capacity
by the facility of propulsion.

Resistance to propulsion is made
up of three distinct components:

(1) Surface friction or "frictional
resistance" which depends upon the
area of submerged or "wetted" surface
and the smoothness and the rough-
ness of this surface.

(2) Eddy making resistance, set up
by abrupt changes of surface con-
formation and is most serious at the
after end of vessels.

(3) Wave-making resistance which
is the power expended in generating
the familiar bow and stern waves.
This is affected by the form of hull
and speed.

Sometimes wave and eddy-making
resistances are grouped under the
name "residual resistance". This is
because frictional resistance is the
only portion which can be fairly ap-
proximated by calculations and if this
is subtracted from the total resistance
the result is the sum of wave and
eddy resistances.

The power actually required to pull
a vessel at various speeds, thus over-
coming the resistances encountered, is
the Effective Horsepower (EHP). Be-
tween the machinery which generates
the power and the propeller or pad-
dle wheel which converts the power
into thrust driving the vessel, there
is mechanical loss due to friction
in the machinery parts, etc. There-
fore, the power at the engines must
be greater than the E II P by the
amount of this loss.

Indicated Vs. Brake Horscpoiver

When power at the engines is de-
rived from indicator cards which show
the work done by the gases in the
cylinders, it is the indicated horse-
power (I H P). If the engine power
is measured by the actual torsion in
the crank shaft it is called the Brake
Horsepower (B H P).

Clearly the less power lost between
engine and propeller, the greater the
efficiency and a measure of this can
be expressed by the ratio of EHP to
I H P or B H P. This ratio is called
the "Propulsive Coefficient" and is
from SO to 70 per cent in ordinary
vessels. Of course it will be higher
when B H P is used than with I H P
because there are losses in the engine
itself between the power developed
in cylinders and that delivered at the
crank shaft. This engine efficiency
B H P

(a ratio of ) should be from 80

I H P
to 92 per cent. »

The surface to which a ship's hull
is formed or molded is known as the
"molded surface". It is parabolic in
nature so that a section in any direc-
tion between a plane and the surface
is a parabolic curve.

If the hull is cut by a number of
planes in various directions, the re-
sulting curves of intersection between
the planes and hull surface show the
character of surface and may be used
as a guide in constructing the vessel.
The drawing so made is called the
"sheer draft" or more often the
"Lines."

Biiovnncv, Draft and Displacement

M AT AMEK— OWNED BY COPLEY AMORY, OF CAMBRIDGE, MASS.
Used in I.abradore; 36 feet long by 8 feet 9 inches beam; driven by Lawley 2-cylinder, 4-cycIe engine

The Design and Constrtictioii of Power Work Boats

CHAPTER IV

Laymgf Down-Fairing tne Lines

HAST chapter we explained as
simply as an intricate question
will permit, the principles in-
volved in designing a workboat
hull. There are certain fundamental fea-
tures of every successful power-driven
boat which must be molded into a homo-
geneous model, otherwise a boat ma}'
be satisfactory in some respects and
entirely lacking in other requisites of
performance.

Now having mastered the principles
of displacement, buoyancy, stability,
etc., we will endeavor to apply them
to the job in hand, of creating a
design from which construction of
the hull may be accurately carried out.
Fig. 14 is the "Lines" for a SO-foot
power tug and consists of three
views; a longitudinal elevation, a plan
view or "half breadth" and an end
view or "body plan". The relative
location of these views is conven-
tionally arranged as in the figure with
the forward part of the boat or the
"bow" toward the right hand.

In the elevation and body plans
a horizontal base line is drawn at the
lowest point and all vertical measure-
ments or "heights" are measured from
this. This base line
is really the edge
of a horizontal
plane and numer-
ous other horizon-
tal planes are shown
at distances above
it. These latter
planes are as near-
ly parallel to the
load water line as
can be estimated
and are called
"water plan es."
They are labeled
"2' 6" W L," "3'
6"W L," "Designed
W L," etc., and ap-
pear as St r a i g h t
horizontal lines in
the elevaticn and
body plans. Where
the hull is cut by
water planes a
series of longitudi-
nal horizontal
curves result. These
c ur v e s can be
shown onlv in a

plan view and are "water lines." They
are labeled in conformity to the watei
plane, which cuts them from the hull
surface.

The upper hull limiting line is
called the "sheer line" and may be
curved or straight in elevation. It
is usually higher at the bow than
at the stern and if curved, its lowest
point is at about one-third of the
length from the stern, the line rising
from this low point to the forward
and after ends.

The plan view of the sheer line
in the half breadth plan is widest
and parallel to the longitudinal center
line at about mid-length. From this
it curves inward to the bow and stern
respectively.

At the extreme ends in the eleva-
tion two vertical lines are drawn
and are the "forward" or "after per-
pendicular" respectively. The distance
between these is divided into ten or
more equal lengths and perpendiculars
are erected at the points of division.
These vertical profile lines are the
edges of cross sectional planes which
are passed through the hull perpendi-

FIG. 15— VARIOUS FOKMS OF STEMS

cular to the base plane and the
longitudinal center plane. The sec-
tional planes intersect the molded
hull surface in curves called "cross
sections" which are shown in the
"body plan" or end view.

The fullest of these sections is
usually half-way between the end
perpendiculars and is called the mid-
ship section. Its characteristics are
similar to Fig. 19, where the section
intersects the half siding of the keel
at the "rabbet line." From this lower
point and depending upon the type of
vessel, a "line of bottom" extends to
the "lower turn of bilge". If the
line of bottom is produced to the
vertical line tangent to the widest
point of the section, the height of
the point where the two lines inter-
sect above the lowest point of sec-
tion, is called the "deadrise". Con-
tinuing from the lower turn of bilge,
the section rounds sharply upward to
the point where it is tangent at the
vertical line showing the maximum
width. This vertical line is the "line
of half breadth" and the maximum
width of section to this line is the
"m o 1 d e d beam."
From the upper
turn of bilge the
section may be ver-
tical to the point
where it cuts the
deck side, and a
vessel with this
type of section is
called "wallsided."
If the upper part
of the section falls
in from the upper
turn of bilge to
the deck at side,
the amount of fall
in from the line
of half breadth is
called the "tumble
home." This fea-
ture is not essen-
tial to efficient de-
sign, being retained
mainly through the
dictates of custom.
The height from
the point where
the midship section
intersects the keel

Tlic Design and Ccnstntction of Po7ver Work Boats

fSMER

CovnTEit

'SxX;y-^TEnN POST
RUPDEn^fOST

^De/iDWooD <~BcTTCfi Of Kcei.

FIG. 16— VARIOUS TYPES OF STERNS

to the upper deck at side is the "mold-
ed depth."

When the deck is rounded up or
"cambered" the crown of deck at
center above deck at side is usually
to the amount of % inch per foot
of deck width. This curvature may
be more or less and is often entirely
dispensed with. Its purpose is mere-
ly to drain the deck, but since few
vessels are on an even keel very
often, camber can be omitted with
attendant gain in simplicity of con-
struction.

The sections forward and aft of
amidships are finer than the midship
section and it is desirable to have
the forward ones U-shaped at their
lower endings, while the after ones
are V-shaped.

When a portion of the hull amid-
ships has the same cross section as
at the midship section, it is called the
"parallel middle body" and it may be

as great as 60 per cent of the length.
The hull forward of the parallel mid-
dle body is the "forebody", that aft
of the parallel middle body the "after
body".

If a series of planes is passed
through the hull at varying distances
from and parallel to the vertical
longitudinal center line plane, the
intersections of these planes with the
molded surface are curves shown in
the longitudinal elevation as "but-
tocks" and labeled "1' Butt", "2'
Butt", etc.

Buttock planes appear as vertical
straight lines in the body plan and
as horizontal lines in the half breadth.
The spacing of buttock planes should
be the same as for water planes.

Fairing the Lines
The process of delineating a ves-
sel's molded surface is called "fairing
the lines". When "faired", the lines
should be smooth, pleasing to the

eye, free from sudden bumps or hol-
lows and the volume of the under-
water body should afford the proper
displacement and location of the
center of buoyancy under the center
of gravity. Proper stability and trim
are dependent on the lines. In gen-
eral, the location of any point on
the hull surface should be the same
height above base line in elevation
and body plans, the same width from
the longitudinal center plane in half
breadth and body plan, and the same
longitudinal location in the elevation
and half breadth plans.

A detailed description of the fair-
ing process will be found in "A Manual
of Laying Off", by Watson, while
elaborated descriptions of displace-
ment, stability and trim calculations
are set forth in "Theoretical Naval
Architecture", by E. L. Attwood.
Forms for Bow or Stem

The bow or stem may have one of
the forms in Fig. IS. (a) and (b) are
"plumb stems" with rounded or
abrupt forefoot. The former type is
extensively used on tugs, lighters and
other small vessels under ISO feet
long. Its name is derived from the
fact that the portion above the water
line is vertical.

Fig. IS-c is a "raked stem", where
the part above the water line slopes
forward, (e) is the stem of a shal-
low draft vessel, differing from the
ordinary plumb stem by the wide for-
ward deck end which is used to push
barges, (d) is a rounded stem, curved
from sheer line to keel and used in
tugs or lighters. (f) is the spoon
bow used in some shallow draft work.
It has relatively high resistance and
is less desirable than type (e) though
simpler in construction.

Various types of after vessels' ends
or sterns are shown in figures 16 and
17. Tugs and lighters have rounded
sterns (Fig. 16-a) with a vertical sur-
face between sheer and knuckle to
which heavy fenders are attached. The
rabbet line which was parallel to the
bottom of keel amidships, rises at the
after deadwood and merges into the
counter. The structural appendages
to which propeller and rudder are
attached should be as narrow as prac-
ticable to reduce eddying.

Fig. 16-c is an overhung transom
stern, the transom being a transverse
plant or cylindrical surface which
may slope as shown or be vertical.
Employed in auxiliary sailing vessels.

Fig. 16-b is the semielliptical stern
used in large vessels. Fig. 16-d is
the compromise stern not common to
workboats because difficult to con-
struct. It is popular in cruisers and
now often adopted in large com-
mercial vessels.

Fig. 16-e, the full transom stern is

Laying Doiuii and Pairing the Lines

used in small boats of all types. The
transom may be flat, cylindrical or
V-shaped.

Sterns for shallow-draft vessels are
of the tunnel or paddle wheel type.
Fig. 17-a shows the elevation plan
and half section of a tunnel stern.
It was originated by the necessity for
a larger propeller than could be fitted
under the hull with the limited draft.
Consequently, a depression was made
in the way of the propeller, as shown
by the dotted lines in elevation and
plan views. A cross section of the
tunnel at any point in its length is
the arc of a circle.

Fig. 18 is the outline in eleva-
tion, plan and section of a paddle
wheel stern. The hull terminates at
the transom, as shown, while the pad-
dle wheel is overhung on two or more
girders.

When the proper stem, stern, mid-
ship section and sheer line have been
decided upon, they are drawn in on
the rectangular layout of water planes,
buttock and cross sectional planes in
the line drawing.

Drazving in the Rabbet Line
The rabbet line joining the lower
end of stem with the stern is now
drawn in the elevation. Its height
above the bottom of keel amidships
equals the depth of keel timber minus
the thickness of garboard plank. The
forward and after endings of the
rabbet line depend upon the cross
sections, but may be roughed in for
final fairing later on.

A line showing the half width of
keel, stem and deadwood is drawn
parallel to the longitudinal center line
in the half breadth and body plans.
Then the width of forward stem

,VI*LHW^y

tLUVATIOh/i

Section A-A

FIG. 17— ST1LRN.S FOR SIIAU.OW DR.\FT VESSELS

edge is indicated by a line at half
this width parallel to the center line
at the forward end of the half breadth
plan. This surface on fore edge of
stem varies from one-half "to three
inches and serves as a backing for
the half round iron bar which is
screwed to it and protects the stem
timber. All water lines end at this
line forward and on the half siding
of deadwood and keel aft.

A trial load water line is now
drawn in the half breadth of proper
width at the midship section and
with forward and after ends fixed
from the points where fore edge of
stem and rabbet line are cut by the
load water plane in the elevation.

Then two sections located midway
between amidships and the ends can
be derived from the half breadth by
taking their widths on the trial
water line and the sheer line. These
widths are placed at the proper levels
in the body plan, care being taken
tliat the forward section is on the
right and the after section on the left
of the vertical center line. The
height of sheer and of rabbet on these
sections is measured from the eleva-
tion.

Intermediate water lines are then
drawn in the half breadth plan by
taking widths from the three sections
already shown in body plan, and by
finding the forward and after endings
in the elevation.

These water lines should always
spring to a fair curve when using a
slender wooden "spline" or "batten"

, WHfO.

FIG. 18— PAUDLE WHICKL STERN

which is bent through the points
through which the line should pass.
If this cannot be done, the batten
should pass through a majority of the
points and spring fair between them.
The corrected line may then be drawn
in and the width of section
through whose spot the batten would
not spring, should be made that of
the fair line on that section and
transferred to the proper water plane
in the body plan. The section curve
should then be corrected to pass
through this new point and the other
fixed points.

A buttock line half way between
center line and molded beam line can
now be drawn in the elevation, taking
the heights from intersection of the
chosen plane with the sections of the
body plan and transferring these
heights to their proper sections in the
elevation. By squaring up from the
half breadth to the elevation, the
longitudinal locations of points where
the water lines and sheer line cut the
chosen buttock plane, it is possible to
obtain the abrupt curvature of the
ends of the buttock line.

Continuing this fairing process for
the remaining water lines, buttocks
and sections, correcting all unfair
points as the work proceeds, the lines
will finally be "faired".

Next the volume of displacement
should be calculated as heretofore
described and if the ship's weight is
such as to result in proper draft and
trim, the lines are complete. If this
is not the case, the proper volumetric
correction must be made before mak-
ing the "'ofifset table" which gives the
molded surface dimensions of all the
lines.

A final check on the fairness is
obtained by passing diagonal planes,
shown in the body plan of Fig. 14.
The slope of these planes is such as
to be at nearly right angles to most
of the sections and to cut the bilge
of the midship section. Such a plane
cuts a curve called a "diagonal" from

The Design and Construction of Poivcr Work Boats

the hull surface.
Sometimes more
than one diagonal
is employed. The
true shape of a
"diagonal" is ob-
tained by "expand-
ing" the inclined
plane into the
horizontal. To do
this, the plane is
assumed to revolve
about its intersec-
tion with the lon-
gitudinal center
line plane, so that
the curve is shown
as it really ap-
pears on the di-
agonal plane. The
exact distances
from the center
line are measured

TunBLB Hone:
3HECFI LiriB

CAMBrH

-ffABBET LirfS

<porTon OF HE£i-

'UPPER Tuffii ofBiloe

TVffff OF 0/t&£
OCAD ff/se

^SASE Li He

FIG. 19— ILLUSTRATING A TYPICAL BODY SPXTION

Dimensions of the
different lines at
the va r i o u s sec-
tions are record-
ed in three
groups: those
showing heights of
sheer, buttock and
rabbet lines above
the base in the ele-
vation ; those giv-
ing widths of sheer,
water line and
keel from the cen-
ter line in the
half breadth
and those giving
true distances
along the diagonal
plane from the
center line to each
section in the
body plan. All

along the diagonal plane to each lines, and the distances along the offsets are recorded in three fig-
section in the body plan and are diagonal to these two can be ex- ures representing feet, inches and
then laid off below the center line panded at the points so found in the eighths of inches. For example, in

in the corresponding sections on the half breadth.

half breadth plan. The offset table is used as a

The heights at which the inclined guide for drawing the lines in the

plane cuts the transom and the half boatyard to the full size of the ves-

siding of stem are transferred to the sel. This is done on a smooth floor

elevation and squared down to the called the mold loft and ensures elimi-

half breadth plan. This gives the nation of the inaccuracies which would

longitudinal location of the diagonal result if molds were made from the

endings at the transom and the rabbet original small scale line drawing.

the table on Fig. 14, the figure to
the right of the word "sheer" and
directly below "stem", is 9-1-0. This
indicates that the stem is 9 feet
1 inch above the base line at the
stem.

The profile and plan of stem and
stern should be dimensioned in the
elevation and half breadths, to estab-
lish their true outline.

CHAPTER V

Stem, Keel and Stern Design

^>^^^^HE fore end of a vessel is a
M C^\ ridge formed by the intersec-
^ I tion of the side surfaces, the

^•^^ structure consisting of a bar
called the stem. This bar may be of
wood or of steel in conformation to the
material composing the hull. Attached
to the stem are the side planking or
plating, the longitudinal framing of
the hull, the forward end of the keel
and keelsons, and some of the ex-
treme forward frames.

Stem construction for wooden ves-
sels is shown in Figs. 20, 21 and 22.

Fig. 20 is the stem of a wooden tug
between 90 and ISO feet long. The
stem log is backed by an "apron",
both timbers being fastened together
with through bolts having counter-
sunk heads riveted over ring wash-
ers. Where the longitudinals end and
at the deck, these bolts extend through
heavy knees called "breasthooks".
The lower ends of stem and apron
are scarphed to the stem knee and its
backing timbers (called the forward
deadwood) as shown. In Fig. 22 the
stem of a larger vessel, the deadwood
is heavier; while in Fig. 23, the stem
of a large vessel (250 to 325 feet
long), the forefoot is formed by two
knees scarphed to the stem, apron,
keel, keelsons and filling piece, the
whole being backed by deadwood
timbers.

Fig. 21 is the stem of a small ves-
sel or shallow draft one with model
bow. The stem and keel are con-
nected by a natural crook knee, mean-
ing one in which the grain follows
a curve. These knees (formerly of
hackmatack but now frequently of
locust, oak or fir), are cut from tree

Stopwatar

FIG. 21— STEM OF A SMALL POWER
WORKBOAT

stumps, one arm of the knee being
in the lower extremity of the trunk
and the other in one of the large
main roots diverging therefrom. The
single knee forefoot is applicable to
..mall vessels only, being limited in
use by the maximum size of knees
available. It is unusual to obtain these
with arms longer than 6 feet.

(A-A), (B-B) and (C-C) in Fig. 20
are cross sections at various points
in the stem structure. The hull plank-

frames are notched into the dead-
wood as in section at frame (1),
Fig. 23.

The construction of a "spoon bow"
for shallow draft vessels is as indicat-
ed in Fig. 24. One or more heavy
"bow timbers" extend across the for-
ward hull end, being scarphed to
receive the deck, bottom and side
planking. The trusses ordinarily built
into the shallow hull for longitudinal
strength, terminate against the bow

^Rabbet Line
'SBsaiStprr) Bo

'and

C-C

FIG. 20— STEM OF A WOODEN TUG

ing joins the stem and keel at a
recess or "rabbet", the intersection
between outside of plank and side of
keel or stem being the "rabbet line".
In large wooden vessels with "mod-
el" or ship-shaped forms, the stem
is arranged somewhat as in Fig. 23.
Apron and stem terminate at their
lower ends in scarphs bolted to knees
and deadwood. The keelsons and
keel scarph into the after knee, while
the space between end portions of
these and the knee is fitted with a
filling piece. The extreme forward

i'op Wafer

■Sropy^ai'^''

FIG. 22— STEM OF A LARGE VESSEL
250 FEET LONG

timbers; while the space between
these timbers and the first beam and
floor, are fitted with filler pieces. A
filler is also fitted at the intersec-
tion between upper and lower chords
(if the dimension "d" is small enough
to bring this about).

Auxiliary sailing vessels are fitted
with "clipper stems" afifording a
maximum outreach for the forestays
with increased jib areas. Fig. 25 indi-
cates construction of the upper part
in wooden clipper (or overhang)
stems.

Keels form the strong center line
girder connecting lower extremities of
stem and stern post. Since their
function is contribution of longitudinal
strength, it is essential that their
structure be continuous. In wooden
vessels this feature is particularly
necessary but is prohibited by limited
lengths in which timber is obtain-
able. This in turn varies with kind
of timber.

Oak formerly was almost altogether
used in keels. Oregon fir now has
become popular, principally because
of its large sizes, long lengths,
strength and durability.

The Design and Constnietion of Power Work Boats

When the vessel is of such size
that a continuous keel timber is un-
obtainable, two or more lengths are
"scarphed" together as shown in the
longitudinal section of Fig. 26. The
"hook scarph" here shown is securely

Fig. 27. An intercostal filler is lilted Figs. 31 to 36 inclusive are various

lietween keel and keelsons while the types of sterns in wooden vessels,

frames have no joint in the center An auxiliary schooner or large cargo

line. The lower keelson is shown carrier (ISO to 300 feet long) may

notched over the frames. have an overhung transom stern

Fig. 28 is the keel and keelson of ('■'S- 31). The keel extends beyond

a wooden tug with continuous trans- ^^^ rudder post, forming a lower

verse frames; while Fig. 29 is a step-bearing for the rudder. Both

similar detail of boats 50 to SO feet s'^""" ^"d rudder posts mortice into

The keelson in the latter is '^e keel, the "shoe" between their

long.

directly on the keel, forming there-
with a rabbet and having the frames
butted on the center line. Additional
longitudinal strength is contributed
by the engine keelsons which are
notched over the deep transverse

FIG. 23— STEM OF A LARGE WOODEN
VESSEL

FIG. 24— CONSTRUCTION OF SPOON

fastened with countersunk head bolts
with ends riveted over ring washers,
the recesses at bolt ends being plugged
in white lead. (Fig. 26-a.)

Fig. 23 shows a cross section and
a longitudinal section of the center
line hull bottom girder formed by
conjugation of the keel and center
line "keelsons". The five keelsons
(as large as 18 x 18 inches each) are
bolted together horizontally and ver-
tically, their scarphs being spaced
well apart to avoid excessive weaken-
ing, l-ong vertical bolts (b) pass
from keelson through the double
frames to the keel. Shorter tlirough
bolts connect keelsons to frames out-
board of the keel. The false keel
is spiked to the keel proper over
the metal hull sheathing and is read-
ily detachable when worn.

The extra heavy planks adjacent
to the keel and called the "gar-
boards" are sometimes rabbeted in:o
the keel (Figs. 27, 28 and 29) or
they may be fitted closely against the
keel as in Fig. 26. Where garboards
are of considerable thickness, they
may be edge bolted to the keel.

At points where scarph joints cross
the rabbet throughout the stem, keel
and stern, wooden plugs called "stop-
waters" are fitted across the joint
(Figs. 17 to 23 and Fig. 26). These
prevent entrance of seawater through
the joint into the hull.

The keel of a wooden schooner,
110 to 160 feet long, is shown in

lower ends being reinforced by nat-
ural crook knees which form the lower
arch of the propeller aperture.

The line of counter is formed by

a heavy "horn timber", morticed to

take the upper end of the stern post

floor timbers and extend as far fore and to permit passage of rudder post

and aft as practicable. and stock. The forward end of horn

Shallow draft vessels may be as in timber extends into the hull and is

Fig. 30 or the keel may be of same securely bolted to the deadwood and

shaft log, against which it terminates.
Notice the way the beveled ends of
all timbers are cut to prevent feather
edges. At its upper and after end
the horn timber is let into the knuckle
timber (Fig. 31), or the rim logs
(Fig. 32).

The propeller shaft passes through
a hole cut in a "shaft log" which
has a stuffing box at its inboard end
and is morticed to the sternpost at
its outer terminus. Great care must
be observed in boring out the shaft
log, particularly if it is long, so that
alignment with machinery may result.
Sometimes it is made in halves (sec-

U(JW FOR SHALLOW DRAFT BOATS

thickness as remainder of bottom
planking. The reduction in strength
is justified by considerations of draft

increase of interior hull strengthen-
ing.

Drainage of bilge water in all these
types is effected through "limber
holes" cut in the frames as shown.
Galvanized "limber chains" pass con-

and is reimbursed by corresponding tion "A-A" Fig. 32), facilitating this.

All such joints must be well coated
with thick white or red lead and
securely bolted. Shaft logs may be
lined with a lead sleeve bedded in
white lead and flanged at the extremities
under flanges of stuffing box and
stern bearings. Ordinary pipe may be
used here and threaded into the
fittings at its end, sufficient clear-
ance about the shaft being provided
to insure against binding.

The frames whose lower ends con-
verge at acute angles at the stern are
let into deadwood timbers and secure-
ly through bolted. Abaft the stern-
post they butt against the horn tim-
ber, which is rabbeted to take the

FIG. 2,i— CLIPPER STEM OK Al'.XlI.
lARY SAILING VESSEL

Limber
St,

7rornav6r3e ■5e>ofian

Lonijiucllnal Sccticn

FIG. 26— CON.STRUCTION OF BOTTOM GIRDER OF LARGE WOODEN SHIP

hull plank ends as indicated in Fig. 31.
The upper end of rudder post is
securely bolted to the deck beams and
forms the forward side of a watertight
box or "rudder trunk" through which
the rudder stock passes to the quad-

tinuously through these holes so that
when drawn back and forth the holes
will be cleared of clogging matter.
The "limber strakes" fitted in the
ceiling of large' vessels afford access
to the limber holes.

Stem, Keel and Stern Design

rant or tiller. A stuffing box em-
braces the stock at top of trunk un-
der the "rudder support bearing"
which carries the weight of the rudder
The trunk is large enough to permit
unshipping the rudder.

"hrouqk'Bol+'-

FIG. 26a— HOW KEEL BOLTS ARE
COUNTERSUNK

The rudder blade is formed by
heavy timbers fitted as shown and
edge bolted together. Metal straps
assist in tying them together and are
formed into sockets at their forward
ends. Hinge bolts or "pintles" fit
into these sockets or "gudgeons" and
corresponding ones on the rudder post,
the gudgeons sometimes having me-
tallic bushings. Notice that the rud-
der stock extends in one piece to
the keel. Where this is impracticable
the two lengths should be securely
scarphed. Lugs called "stops" on the
rudder post should bear against sim-
ilar ones on the rudder stock, pre-
venting a rotation of more than 45
degrees on each side of center line.
Rudder chains, shackled to an eye
on the rudder blade are led to pad
eyes on each side of the stern and
serve as emergency stops in event of
breakdown.

Between the knuckle and upper
deck, transom frames are fitted as in
Fig. 31, the transom planks extend-
ing athwartships being fastened there
to. The outline of transom forms a
knuckle and a heavy timber conforms
with it, being scarphed to take the
ends of the hull and transom planks.
The knuckle timber and rim logs
(Fig. 31) form parts of this transom
margin log.

Tugs and power lighters have us-
ually but one deck and a semi-elliptical

Tfobbct

FIG. 27— KEEL OF A WOODEN
SCHOONER

Stern whose general construction is
as heretofore described. In Fig. 32
the main point of difference is at the
deck where heavy rim logs are shown
and a guard timber is securely bolted
to these. The rudder stock passes

through the deck and is covered by a
grating upon which Iiawsers are
stowed. Sometimes the quadrant is
below decks. Sterns of this type
are common to tugs and lighters be-
tween SO and ISO feet long .

Full transom sterns (Fig. 33) are
common to small craft of all descrip-
tions up to 80 or 90 feet long. The
transoms may be variously formed as
previously described but the same
general construction applies for all of
them. Keel, deadwood, shaft log and
horn timber have already been con-
sidered, except that where a metal
rudder is fitted the shoe is formed
by a casting as shown.

Hechon

Rabbtt

FIG. 28— KEEL OF A WOODEN TUG

The rudder stock passes through a
lead-lined opening in horn timber and
bearing log. A natural crook knee
connects horn timber keelson or
stringer ends to transom framing.
Cheek plates are sometimes fitted
over the junction of shaft log and
deadwood with sternpost.

The proper rudder areas for vari-
ous small boats will be considered
under steering gear. In event of
breakdown to this gear a spare tiller
may be inserted through the deck
plate shown in Fig. 33 and fitted over
the square rudder head.

^Enain

HcalsonS

FIG. 29— KEEL OF A 50-FOOT
WORKBOAT

Transom sterns properly formed
are desirable for the additional hold
storage space, the wider deck, the
tendency to prevent squatting when
under way and the facility of con-
struction. They do not render a
vessel difficult to steer nor make
her uncomfortable in quartering seas
unless they are extremely broad and
flat underneath.

Compromise sterns (Fig. 34) are
seldom fitted to commercial power
boats. They are similar in structure
to the stem, having a central ridge
formed by the horn timber, a knee
and the stern log. The planking
scarphs to these timbers and care must

be observed that the plank ends fit
properly and are not too narrow.
The flat iron shoe shown in Fig. 34 is
not recommended but is indicated
merely as common in pleasure boats.
Such a shoe affords little protection
to the propeller since it is liable to
distortion on contact with submerged
obstacles, in which case the rudder
may be thrown out of alignment or
twisted and jammed.

Shallow draft sterns with stern-
wheels are as indicated in Fig. 3:.
The flat bottom planking rises to
a transom whose lower edge is at or
near the water line. The hull is not
pierced as in vessels formerly con-
sidered but rudder stocks extend
up to the house deck as shown.
Bearings at the transom and house
decks support these stocks and the
tiller arms are linked together over
the house or "texas".

Multiple rudders are necessary be-
cause of the limited draft and un-
wieldiness of the boxlike hull. The
forward upper edges of these rudders
are very close to the bottom planks
so that obstructions cannot wedge

l«*4«\/^

ri/ss

Gorboard

FIG. 30--KEEL OF SHALLOW DRAFT
VESSEL

themselves between rudder and hull.
Details of construction will be consid-
ered under steering gear.

The stern wheels, whose details of
construction will be later taken up,
are supported upon two or more
overhung girders whose inboard ends
securely bolted through the main
deck to the longitudinal trusses in
the hold. If the continuous trusses
do not end under these girders it is
necessary to provide auxiliary trusses
or other reinforcing. The extreme
outboard ends of wheel girders are
connected by a heavy transverse tim-
ber and walkways are provided out-
side of the outer girders to facilitate
inspection and repairs to the wheels.

Vibration is minimized by hog posts
and tie rods as shown which form part
of the longitudinal strengthening truss
above the hull necessary in these
shallow hulled boats.

The paddle wheels revolve in a
clockwise direction, dip of the buckets
being fixed by vessel's draft, but sel-
dom exceeding 27 inches. The after
deckhouse bulkhead is termed the
"splash bulkhead" and is watertight.

The Design and Coiistniclioii of Fotver Work Boats

imrm

VJ^^

*^tal3e teel

7ov

'Shoe
FIG. 31-OVERHUNG TRANSOM STERN OF AUXILIARY SCHOONER

The wheel shaft bearings fitted on
each girder are bolted to timber pads.
Wheel girders are designed as canti-
levers to take the wheel weight but a
high factor of safety must be em-
ployed to allow for the vibrational
stresses. At the same time these
overhung weights are not directly sup-
ported by buoyancy so that care must
be taken not to trim the vessel by the
stern. In most cases it is necessary
to locate the engine and fuel tanks
well forward to oflfset the stern
weights.

Propeller-driven, shallow-draft boats
are very successful if properly de-
signed. Their advantages over stern-
wheel vessels are reduced machinery
weights, less difficulty in obtaining
proper trim, improved maneuvering
qualities, greater free deck space and
compactness of hull appendages.
Higher speed of the propeller permits
of lighter and better balanced machin-
ery for the same power.

Fig. 36 is a longitudinal section
through a wooden tunnel-stern vessel;

Fig. 37 ("a" and "b") are two cross
sections at "A-A" of Fig. 36 for dif-
ferent tunnel constructions. Two or
more propellers are necessary since
the limited draft cuts down permis-
sible diameter and the total thrust
area must therefore be distributed.

The tunnel should be a smoothly
scooped out recess in the vessel's bot-
tom and the propeller tips should
fit into this with minimum practicable
clearance (J/2-inch if possible). The
highest point of tunnel should not
be more than one-third the propeller
diameter above the water line and
the after end should just touch the
water line at the stern. If this is
not practicable, a vertically hinged
flap should cover the after tunnel end,
opening with the stream flow when
going ahead. This is to insure good
backing qualities, the water filling

Full Transom SrrRN

■■5 pare Ttilc-r

FIG. 33— TRANSOM STERN FOR SMAI.I.

r.OAT WITH METAL RUDDER

fcalcuart t-ail

FIG

STERN OF TUG OR LIGHTER WITH SINGLE DECK AND GUARD TIMBER

^—F/of Iron Shoa
FIG. 34— COMPROMISE STERNS SELDOM USED ON WORKBOATS

the tunnel when flap is forced closed
by astern motion.

Cross sections along the tunnel
should be circles with varying diame-
ters and their upper points in the
longitudinal profile curve of tunnel.

Workmanship in wooden tunnel
sterns must be of highest class, since
smooth water flow is essential and leak-
age is likely due t > complex struc-
ture.

In Fig. 37-a the tunnel is merely a
watertight box with arch beams to
whici! is fastened a metal fairwater
top ; 37-b has the tunnel formed
by bottom planks which are cut and
bent into place, calked and fastened to
arch beams inside the hull.

Sinn, Kci'l and Stern Dcsiyii

u J u J u u u I

Stern

=^-/~^.-lL,^'

■iT-^'i— TT- ill! I|

^y^^^i^

'" "

/ ^Multiple ^Dsodwood \^ottOrn

FIG. 35— SHALLOW DRAFT STERN WITH STERN WHEEL

II II

JM- 'ilk kb ' *f' *t '

oHorn

IUNN£.L St£RN
FIG. 36— LO\G[TUniNAL SECTION OF WOODEN TUNNEL STERN BOAT

Co)

(Tunnel
■^ICol-hns

Jection Tti hough Tunnll Sterns

FIG. 37— GROSS SIXTIONS SHOWING DIFFERENT TUNNEL CONSTRUCTION

The Design and Constntction of Power Work Boats

KAMCHATKA— A SAILING VESSEL RECENTLY CONVERTED INTO AK AUXILIARY FOR USE AS A WHALER IN THE

ARCTIC OCEAN AND BERING SEA

144 feet long by 31 feet beam by 15-foot depth. Fitted with a 300-horsepower Macintosh & Seymour diesel engine, which drives her
at 7'/i knots loaded. Two auxiliary engines, one 25 horsepower Burn-Oil, and a 20 horsepower gasoline engine installed.

CHAPTER VI

Application of Steel Construction

long.

^TEEL construction as here
considered will be limited to
practice in commercial ves-
sels between SO and 250 feet
Bar stems are ordinarily fitted in
these and are scarphed to the plate
keel or bar keel as in Fig. 38-a and b.
The length of these scarphs is nine
times the thickness of bar stem and keel
and the scarph faces are machined to
fit closely together (Fig. 38-6). The
shell plating is flanged to the stem and
is connected thereto by through rivets
with countersunk heads. In small ves-
sels a single row of rivets is used but
in vessels more than 75 feet long two
rows of zig-zag rivets are employed.
When bar stems join a plate keel (Fig
38-0 ) their lower ends are flattened out
and riveted thereto (Section Frame 2).
At one-twentieth of the vessel's length
from the stem a transverse watertight
bulkhead extends from side to side and
from keel to upper deck. This is the
"forepeak" or "collision" bulkhead and
the space between it and the stem is the
"forepeak".

Deep transverse floor plates whose
upper edges are stiffened by the reverse
frames, connect the lower ends of frames
and are cut to permit passage of the
center keelson plate and angles (Sec-
tion Frame 2). Where longitudinal gir-
der angles (called keelsons or stringers,

according as they are on the vessel's
bottom or sides), join at the stem, they
are connected by horizontal bracket
plates or "breasthooks" which are con-
nected to the hull plating between frames
by short "shell clips" and have their

after edges stiffened by an angle. Large
breasthook and floor plates are pierced
with "lightening holes" cut from the
least affected part to reduce the weight.
Limber holes drain the spaces between
floors (Section Frame 2).

FloorPlcr^^ci+f

Gorboard
StraK«>

Keelson Plo*6

) Qt-boord
Stroke,

"iSide Bar Keel

'Bacboard
Plote Kee.1 PI 0+6

(b) Co)

FIG. 39— THREE TYPES OF KEELS OF STEEL VESSELS

Floors

, Ke«ldon IS

"P/ frame
Keels

Fowndift'ion "Plate

lonTlate CUpi
To Flo<7r6

Limber
Hole

FIG. 40— METHODS OF FITTING
KEELSONS

KeeliOM cups
To F\oors.

'Foonddftic>r\'T\a\-e

Bar S+er

3c'C.tion

Fra me Z
^/cufei He.e>l
^Bci^ Stem
FIG. 38— BAR STEMS AND METHOD OF SCARPHING

Keels of steel vessels are of three
types: plate, bar and side bar (Fig. 39-
a-b-c). Plate keels are common to large
steel vessels and to those of shallow
draft.

Bar keels are used in tugs, power
lighters and in general for vessels up
to ISO feet long.

Side bar keels are not extensively em-
ployed due chiefly to the difficulty of
obtaining good rivet connections through
the five thicknesses of metal (two gar-
board plates, two keel bars and the
center keelson plate).

The Center Keelsons

Center keelsons form a girder with
the keel and their construction is affect-
ed by the size of vessel together with
the method of making connection with
transverse "floor plates" which are a
part of the framing and will be later
discussed. With respect to these

Tlic Design and Coustriiiiiou of Pozvcr Work Boats

Siringftr A^^^le-

FIG. 43 — CONSTRUCTION

OF OVERHUNG TRANSOM

STERN

Knuckh
r^udd&rTruriK

I? dddfrf Coupling.
f7udd&rFrafTn

-Snoe

"floors", keelsons may be built above
them and extend continuously fore and
aft; the floors may be cut at the cen-
ter line to admit a continuous plate
keelson extending down to the keel ; or
the keelson plate may be intercostal be-
tween floors, with continuous keelson
angles on top of floors.

Fig 40-a is a continuous keelson on
floors, attachment to upper edge of floor
plates being by rivets through the re-
verse frames on one side and a clip on
the other side of plates.

The keelson may consist of two
angles, as shown; of two bulb angles,
four angles with a rider plate over the
upper ones, whose long flange is horizontal,
or four angles with a "foundation plate"
under the lower angles and on top of
floors, a rider plate being fitted over the
upper angles.

When through keelson plates of floor
depth are fitted (Fig. 40-6), the upper
keelson angles may be above the floor
tops, or (in small vessels) below this
level. The upper part of keelson girder
may vary in structure as did the type
entirely above floors. Double clips are
always fitted connecting the keelson and
foundation plates to the floors. When
a bar keel is employed the lower edge
of keelson plate butts against it without
angle connections. In the case of a

Lficai-pul '~Rot«.He*l

Asttt-fi/aK Bulhhcad

1 C_ From} to, R

Sten

plate keel this is connected to the keel-
son plate by continuous double keel
angles (Fig. i^-c).

Fig. 41 shows a center keelson with
intercostal plate and continuous upper

Ivinet BoM-orM

■Vivtrie finable

Foojndatton ,_, ^j/

Floor

FIG. 42— TRANSVERSE SECTION OF
DOUBLE BOTTOM

angles. The intercostal plate is in sec-
tions of frame space length which are
cut to pass the frames and heel pieces
at keel and the reverse frames and re-
verse frame clips at floor top. With bar
keels there is no lower keelson plate

/Plate

-e\ate.

Jy,terco6tal ■<ee\ '^'"'^'fitir^ I III 1 ' i-i I

connection, but double intercostal keel
angles are fitted with plate keels.

Tanks built in the ordinarily wasted
space below floor tops are used for
fresh water, fuel oil or ballast water.
The floor tops are plated over by an
"innerbottom"' or "tank top". Center
keelsons in these "double bottom" com-
partments are composed of continuous
girder or keelson plates with double
keelson angles and top angles to the
inner bottom plating. Fig. 42 is a trans-
verse section through a keelson in dou-
ble bottoms. Generally double bottom
tanks e.xtend the full vessel's length be-
tween peak bulkheads, but often they
are limited to spaces under machinery
compartments. When this is so the
keelsons outside of tank are of the con-
structions in Figs. 39 to 41.

Steel sterns applied to commercial
power craft are ordinarily limited to
those in Figs. 43 to 48 inclusive.

Passenger and cargo or au.xiliary sail-
ing vessels may be fitted with semi-
elliptica! or overhung transom sterns
(Fig. 43), where the transverse framing
extends aft to the "transom floor",
which is a deep vertical transverse plate
against which the upper end of rudder

rBulivark Rail

Bulwcurki

BulwarK BracKet
' or f offlcd S-t-gy
JBitt_liM_WH mi Ml

awser Sraiin^

c«ci ■piate Keel ^

FIG. 41~CI-:NTER KEELSON WITH I.NNERCOSTAL PLATE

FIG. 44— ATTACHING GUARDS AND
RAILS

post is clipped with double angles. The
rudder and stern posts, connected at
their tops as shown and at their lower
ends by a "shoe", form the "stern
frame" forging. This is scarphed at its
forward end to the plate or bar keel,
tapering down to the horizontal plate
connection in the former case and being
connected as for stems in the latter
instance. This keel scarph should begin
at least two and one-half frame spaces
forward of the stern post which is
"bossed" to permit passage of the cen-
ter line propeller shaft, which passes
through a cast steel stern tube to the
after peak bulkhead, where a stuffing
box is fitted.

When twin screws are fitted no screw
aperture is necessary unless the pro-
peller tips overlap at or C(jme close to
the center line. Fig. 45 is a twin screw
frame and indicates the forged stmt
which supports each wing shaft.

The shoe under the propeller aperture
is of flattened elliptical section and ex-

Application of Steel Constniction

tends beyond the rudder post to form
a step bearing for the rudder.

Forged to the sternpost are eyes or
"gudgeons" which receive the pintles
about which the rudder hinges and
which may l»e bushed with metal or
lignum vitx wood. At the upper end
of the rudder post, heavy lugs are
forged to form "rudder stops" which
prevent greater angular swing than 45
degrees.

Large vessels have their rudder stock
coupled to the blade, as in Fig. 43, this
connection being a horizontally or verti-
cally transverse flanged or a scarphed
joint.

Rudder Construction
Double plate rudders (Fig. 43) con-
sist of a forged or cast frame with
plates riveted on each side and the in-
tervening space filled with pine well
coated with pitch or other preservative.
Single plate rudders (Fig. 45) are com-
posed of one plate riveted to forged
arms on the rudder stock.

■Bo++oin Plafm^

FIG. 46— ELEVATION AND PLAN OF STERN WHEEL VESSEL

or serve as a trimming tank when filled
with or emptied of sea water.
Fantail sterns are similar in construc-

the vertical distance between deck and
knuckle is just sufficient to attach the
heavy guard shown in Fig. 44. Being
common to tugs and lighters and con-
sequently constructed for towing, a
bulwark rail strongly supported by
forged stanchions or brackets is fitted.
The tiller or quadrant cannot usually
be installed below deck due to lack of
space, and is therefore covered by an
ash grating upon which hawsers may
be coiled when not in use.

Shallow draft sternwheel vessels have
the same characteristic construction as
was pointed out under wooden hulls,
and Fig. 46 is an elevation and plan of
this type.

A tunnel stern (Fig. 47) has the bot-
tom plating dished to the tunnel con-
tour and the bottom angles forged in
conformity. It is much more readily
and simply fitted in steel than in wood-
en vessels. The stern casting shown
All rudder heads must pierce the hull tion to the overhung type but differ at flanges to the outside of tunnel and has

Rodde*-

Plo\Te»

FIG. 45— CONSTRUCTION OF RUDDERS AND STRUT BEARINGS

through some form of watertight box
or "trunk", at the top of which is a
stuffing box and the rudder support bear-
ing, surmounted by the steering arm or
quadrant. This trunk is connected to
the afterside of transom floor and
shaped to permit unshipping the rudder.
The side and top trunk plates are con-
nected by forged angles caulked water-
tight.

Aft of the transom floor ordinary
transverse framing is supplanted by ra-
diating "cant frames" and beams,
strongly bracketed together and at their
forward ends to the transom beam and
floor. Cant frames are spaced around
the knuckle at intervals equaling the
ordinary frame spacing amidships.

A watertight "flat" or short deck
usually extends from after the peak bulk-
head to sternpost, the space beneath
which is too fine and congested for
cargo stowage and is termed the "after
peak tank." It may store fresh water

the deck marginal connection, where a bearing at the after end with the

FIG. 47— HOW THE BOTTOM PLATING IS DISHED FOR TUNNEL STERN

--i-vHK--L L

FIG. 48— STERN (OR BOW) OF DOUBLE ENDED STEEL FERRY BOAT

28 The Design and Construction of Power Work Boats

usual stuffing box inboard. frames need not be fitted though they der. In such a case the rudder may be
The stern (or bow) of a double-ended sometimes are, particularly in wooden formed to fair into the normal hull sur-
screw steel vessel, such as ferry boats, vessels. Heavy longitudinals should, face, but this is an unnecessary elab-
is shown by Fig. 48, the peculiar con- however, be introduced to absorb the ^^^j|^^ ^^^ forward rudder is al-
tour of stern frame being the only rad- end thrust in docking. When side pad- . > . . ,• ■ ^ l
ical departure from ordinary stern con- die wheels are employed the screw aper- ^^^^ ^'^^^'^ °" *^^ «"'^'" ''"^ ^"^«'' ^^
struction. Because of the relatively ture is dispensed with and the sternpost =» through pin from the deck or by lock-
wide ending of deck in this type, cant is located close to inboard edge of rud- ing the rudder stock.

CHAPTER VII

Wooci and Steel Transverse Framing

CHE watertight hull cannot be
made sufficiently thick to with-
stand longitudinal, transverse
or local stresses, for the light
displacement would be thereby in-
creased to an uneconomical degree;
even assuming that the required
strength could be brought about by
such cumbersome construction. An
inner system of framing accordingly
has been introduced to suitably re-
inforce the skin and is called the
framing.

It can be readily seen that this
framework must run both longitudi-
nally and transversely, and that one
system must be predominant because
of structural limitations. Now the
most severe strains are ordinarily
longitudinal in character, which would
make it desirable to run the princi-
pal framing in fore and aft directions.
This is practicable in steel and small
wooden ships, though the construction
is complicated by the warped and
refined hull surface at the vessel's
extremities.

(a) Wood Framing

Large wooden vessels (100 feet
long and above) cannot be rigidly
constructed with longitudinal frames
because the framing timbers are rela-
tively short, the end connections be-
tween timber lengths weak, the tim-
bers cannot be suitably bent and
beveled without serious loss of
strength by cutting across grain, and
finally the planking which is in nar-
row strips could not be properly fast-
ened. To run this hull planking trans-
versely would seriously increase the
resistance and result in loss of
strength by the already comparatively
weak structure.

Framing of Wooden Vessels

The transverse framing of large
wooden vessels is similar to Fig. SO.
Here the frames, relatively heavy tim-
bers, are sawn to shape and fitted in
two thicknesses (doubler), with butts
of sections in each thickness stag-
gered with those of the adjacent mem-
ber of that frame. Butt joints at the
center line are avoided and the molded
dimensions of timbers (that measured

in the vessel's transverse planes) may
be constant or gradually decreasing
from keel to frame head at upper
deck. The two sections of each frame

FIG. 49 — CONSTRUCTION FOR TUGS
AND POWER LIGHTERS

are bolted together. Sided dimensions
of frames (measured in fore and aft
direction) are usually the same from
keel to head.

Except at the vessel's extreme end,
all frames are perpendicular to the
keel. At the ends where the inward
curvature of water line would entail
extreme bevel with accompanying loss
of frame thickness, the frames are
placed nearly at right angles to most
of the water lines. These radiating
frames, called "futtocks", are shown
ir Fig. 50 (a), which is a plan view
of the vessel's end framing with the
ceiling and longitudinals omitted.

When wooden bulwarks are fitted,
one of the double frame heads passes
through the deck margin planks to
form a bulwark stanchion. Every al-
ternate or third frame is thus ex-
tended.

Frame heads are connected to the
deck beams by continuous longitudi-
nal clamp and shelf timbers, as
shown.

In wooden construction the deck
beam ends do not always butt against
nor lap on the frame heads, though
this should be so if practicable. At
least every third or fourth beam
should be directly connected to frame
heads by heavy natural crook timber
knees the intermediate beams landing
on the clamp and shelf which are
through bolted to these and the frame
heads.

Limber holes must be cut at the
lowest point of frame heels providing
longitudinal drainage for bilge water
to the pump suctions. In wooden
ships limber chains are fitted in these
holes.

Tuys (Did Power Lighters

Tugs and power lighters have mid-
ship sections similar to Fig. 49. The
frames cross or are butted at the
center line, tapering to reduced
molded dimensions at the deck. Ex-
cept in extremely light construction,
frames are sawn in sections with
double timbers and staggered butts,
through bolted longitudinally. Light
frames may sometimes be bent to
shape but this is not practicable with
large timbers which tend to split and
are stiff. Bending is preceded by
steaming the timber in a box and
then forming it to the proper crook.
Frames in shallow draft vessels are
straight on the bottoms and sides,
butting against a timber called the
"bilge log" at each bilge. (See Fig. 5L)
Where considerable deadrise exists
and always in the machinery space,
heavy transverse floor timbers should
be fitted at the lower point of frames
on center line. These floors are
sometimes introduced all fore and aft.
Wooden deck beams extend in one
length from side to side except where
hatches or other deck openings neces-
sitate cutting them (Figs. 49 and 50).
In this case the resultant "half beams"
are butted against or mortised into
heavy longitudinal "carlins" which
bound the opening.

The weather deck beams are some-
times sawn to a camber on their up-
per edges, the lower edge being flat
and the ends reduced in depth. When
beams are light enough to permit,
they may be steamed and bent to cam-
ber. The outer ends of beams should
be notched over clamp timbers and
kneed to frames, as previously de-
scribed. Inner ends of half beams
where the stanchions are fitted should
have a natural knee.

Hold beams consisting of heavy
double timbers widely spaced, are in-
troduced in larger vessels. The beam
ends bear on hold stringers or shelf

The Design and Conslntction of Pozver Work Boats

ffail Leg

Oul itrtrh 3tQnth\or\

Filhng Block
Qetweeit Frame
Hca/i

FmURE A-S-(h)

Hull Plank

FievttE 49 fi)

FIG. SO— TliANSVICKMC ]■ lIAMINr,' UK L.MMilC \\(10i)i:.\ VESSKLS

and cianip, to which they may be necting upper end of frames to deck
kneed in vertical and horizontal direc- beams, deck beams and stanchions
tions. Where stanchions mortise supporting these.

through double hold beams, metal Frames may be one of the various

cheek straps should be fitted (Fip. 50). structural shapes shown by "Sections

Stanchions supporting the uccks at A-A" Fig. 52. Angles and channel
are fitted in wide vessels and deep
holds. They should always be on a
frame and their lower end or "heel"
should bear on a keelson and have
wooden knees. Sometimes a forged
metal strap is employed at heads and
heel connections or the heel may
notch over a keelson and be through
bolted. (Fig. 49.)

Stanchions should always be fitted
at each corner of large deck openings

KIG. 51_FR.\MES FOR .<^II.\M.O\V
DRAFT VESSELS

center keelson, and were shown in
diagram of the latter. When floors
are not cut at center lines the frame
heels butt at this point and a heel
bar 3 feet long is fitted on the oppo-
site side of floor.

Good Riveting is Essential

Reverse frames which stiffen the
inner edge of frame angles and ex-
tend along the floor tops on side
opposite to frames, form an inner
flange to which keelsons, stringers
and other members may be conven-
iently attached. The overlap of frames
and reverse frames should be suffi-
cient to ensure good riveting. When
frames are of bulb, channel or zee
section, reverse frames are fitted on
upper edge of floor plates only, but
ordinary angles and reverse bars are
used at the ends of the vessel where
the channels and "Z" bars would be
difficult to bend and bevel.

Reverse frames at floor tops are
single except under machinery foun-
dations where they are doubled. At
the vessel's ends it is necessary to
keep the athwartship frame flange in
a transverse plane and to bevel the
shell flange in conformation to the
hull form. (Fig. 52.) This bevel
should always be "open", that is, the
angle between flanges should never
be less than 90 degrees. This is es-
sential to good riveting. The lower
ends of frames at the vessel's bow
and stern are lapped at the keel and
riveted together.

Tlie bending of steel frames to
proper contour and bevel is per-

and to every third intermediate frame '^^''^ ^""^ most frequently used. They formed by means of templates as

at hatch cabins. The upper ends or
"heads" should be strongly kneed to
carlins and deck beams.

When fitted in holds, stanchions
should support adjacent beams
through a longitudinal girder fitted at
heads. (Fig. 51.)

In shallow draft hulls the hold
depth in proportion to beam and
length renders it imperative to intro-
duce strengthening "trusses" running
longitudinally and athwartships. In
these trusses the girders at stanchion
heads and keelson at heels are termed
the upper and lower "chords". Diag-
onal tie timbers serve as compression
members against racking. (Fig. 51.)

The longitudinals are from one to
four in number depending on the
beam. Transverse trusses or simply
"transverses" are at every tenth or
twelfth frame.

(b) Steel Framing

Fig. 52 is the midship section of a
steel tug or lighter. The transverse
framing is composed of frames ex-
tending from keel to deck, floor plates
at keel, knees or beam brackets con-

are spaced from IS to 27 inches apart guides which are secured to a heavy

and are in one length from keel to cast metal slab. The frame bar is

deck. Frame ends at keel are de- heated, placed on the slab and bent

pendent upon the type of keel and against this template, the standing

I An^le.

^Fi^au- Channt,!-. fVoct-ttor Srtaptt

FIG. 52— MIDSHIP SECTION OF STFJ^L TUG OR LIGHTER

Wood and Steel Transverse framing

(lange being properly beveled at the
same time. Spring "clogs" of round
bar iron clamp the horizontal frame
flange to the "bending slab" being
driven into square holes closely spaced
in the slab. Bevel templates of light
wood or metal, cut to the proper
slope which has been obtained from
the lines, are used as guides in prop-
erly beveling the standing flange.

Machines for bending and beveling
structural shapes have been employed
successfully in many shipyards.

The shell flange of frames must
bear directly against the hull plating
and since the longitudinal strakes of
this are usually lap jointed, it is clear
that either the frames or plates must
be joggled (Figs. 52 and 53).

The practice of bending frames to
a fair curve and fitting liner pieces
between shell flange and outside hull
plates is still used but should be
avoided because of the excess weight
of structure and generally unsatisfac-
tory structural fitting resulting there-
from.

Where the Main Deck Overhangs

Passenger and ferry boats for in-
land waters usually have the main
deck overhang the hull. This over-
hang may be supported on brackets
or be formed by a sudden hull pro-
tuberance above the waterline (Fig.
S3a). In the first construction the
transverse framing resembles that for
tugs or lighters, while in the second
the frames are knuckled to conform
with the deformed hull surface. This
overhang is to afiford a maximum of
deck space with minimum permissible
beam of actual hull, so that the speed
may not be seriously reduced.

Shallow draft vessels (Fig. 54) have
straight frames on their bottoms and
sides. The bilges are usually rounded
and a bracket may be introduced to
join side and bottom lengths. This
avoids furnacing the frames and is as
satisfactory a construction as when

-D«tl« House [TexasJ

,Coamtrn?life

Met.l Psr.der

10) (W CO

FIG. 54— SHALLOW DRAFT VESSELS HAVE STRAIGHT FRAMES

Ul^H'C-ni

the side frames are bent to the bilge
radius and overlapped on the bottom
frames (Fig. 54a). In small vessels
it may be possible to obtain the frame
shapes in sufficient lengths to extend
in one piece from gunwale to gun-
wale, but this is not ordinarily feas-
ible.

Square bilges with heavy bilge
angles connecting the side and bot-
tom plating may be employed and if
the hull ends are properly modeled
this will not prove a serious detri-
ment to efificient propulsion. Bilge
brackets are in this case also em-
ployed. (Fig. 54b.)

Of late the bilges have occasion-
ally been cut at an angle and a flanged
bilge plate fitted to forged frames.
(Fig. 54c.)

Web frames (Fig. 52) are fitted on
every sixth to tenth frame and at the
ends of the large hatches or fore-

'^:::'-'0

-Dauble I26/«'-s« F">-aivi<i

FIG. 53— WHERE THE MAIN DECK
OVERHANGS THE HULL

castles, bridges and poop erections.
They consist of a web plate from 14
to 42 inches wide connected to the
hull by single or double angles and
faced with half round or angle "face
bars". The outline of a web frame
is indicated by the broken line in the
midship section (Fig. 52). The lower
ends of web frames fair into floors
and are connected thereto by lapped
joints. The face angles continue along
upper edge of floor plates in similar
manner to reverse frames. Web
plates may have lightening holes cut
in them.

Floor plates from 8>^ to 36 inches
deep at the center line form trans-
verse brackets at the lower ends of
side framing. The depth at a dis-
tance from center line of J4 the half
beam must be at least half what it
is on the center line for large vessels.
With a flat bottom this sometimes
permits of sloping the upper edge of
floor plates downward and outward to
save structural weight and gain hold
space.

It is usually preferable to have the
upper floor edge horizontal and in
small boats this is usually done re-
gardless of the consequent reduction
in overall width of floors.

Where the side frames join the
floor plates the reverse angles diverge
from the frames crossing the bottom
of vessel at the upper edge of floors.
If frames are of channels, zee bars,
or bulb angles, these may be run
along the lower edge of the floors to
the keel and a reverse angle bar be
fitted to upper edge of floors on the
opposite side to the frames. Such
reverse bars overlap the frames at
the outboard floor ends. (Fig. £2d.)

The Desiijn and Construction of Po7t'er Work Boats

In the Machinery Space

Sometimes the channels, bulbs or zee The saving in furnace work and fitting portion to their sectional depth ren-

bars are split at their junction with expense of the attached members of ders it necessary to support them at

the floor ends and the upper portion the ships' structure is considerable. intervals by stanchions extending

forged to join the reverse bar on floor Where hatches or trunks necessitate to the vessel's bottom. The unsup-

tops, while the lower half joins a cutting deck beams the severed beam ported beam length should not exceed

frame angle at lower edge of floors ends are connected by angle clips to IS feet for ordinary construction and

(Fig. S2c). a strong longitudinal coaming plate must be less than this if heavy deck

which forms a girder supporting the loads are carried.

deck sides between the hatch ends. Stanchions may be disposed longi-

Floor plates in machinery space Heavy girder beams at the ends of tudinally on alternate frames or they

should be thickened by 0.04 inches these deck openings take the abut- may be widely spaced with girders

and the reverse bars be doubled at ments of longitudinal coamings and under deck beams connecting their

their tops. In the peak tanks at the are built up of a plate witli upper and heads. Closely spaced stanchions, as

forward and after ends of vessel, lower angles. These heavy beams the former are termed, may be of

floors are deepened to form stron.g are usually bracketed to web frames. solid round bars or of extra heavy

brackets .'.t the acute lower interser.- In forming beam brackets to frames wrought iron pipe welded to forged

tion of the hull sides. The reverse it was formerly common to split the heads and heels. This type should

angles are also fitted at their tops, beam section, bend tlie lower por- be fitted at the corners of all hatches

ana floois in after peak tanks some- tion downward and weld a piece of

times support the shaft tube which plate into the forked opening at beam

pierces them. ends thus formed. This expensive

All floors may be lightened by cir- method has been replaced by . rivet-

cular or elliptical holes cut at their ing beam and frame ends to a bracket The heel is forged to a flat palm in

neuiral axes. Care should be tak'ir. plate (Fig. 52) whose inner edge may this case, but if the stanchion steps

that depth of lightening holes does, be flanged (Fig. S3), and into which on a steel flat the heel is connected
not exceed one-half
the depth of the

and large deck openings.

Fig. SSa shows a closely spaced pipe
stanchion with head having a vertical
palm connected to a bulb angle beam.

flrtMll4»tsV>l^

A+Huior't'ahilP

Lon(\i'todina\
E\«vation

LonnlTudinol J \ f

I + H

id)

le)

3 MMM

Inner

FIG. 55— STEEI. STANCHIONS AND STANCHION HEADS

plate. Deck beams gl^-^Jl" p

are of angles, bulb fe|,_^_ r'

angles, channels or

bulb Tees, fitted in

one length across

the deck and brack-
eted at the deck

side.- to ihe frame

heads. -Angles, bulb

angles or chamiels

face in opposite di-

r e c t i o n to the

frames .so that they

may be connected

back to back at

the beam brackets.

When the deck is

of steel plating,

beams are fitted on

each frame while

with a wooden deck the steel beams lightening holes may be cut.

are on alternate frames. The depth ("d" Fig. S3) at the in-

It is common to bend or "crown" ner bracket end on deck beam should

deck beams upward in a circular arc not be less than six times the diame-

so that the heiglit at center above ter of rivets connecting the bracket

sides is J^-inch per foot of deck width to the beam; while the depth "h"

at the particular beam considered, and length "w" of bracket sides on

This camber was formerly claimed to frame and beam respectively, should

contribute transverse deck strength be three times the beam depth.

due to the arching efi^ect. The fal- In holds of considerable depth it

lacy of this theory is tliat all arch becomes necessary to introduce widely and the foundation channels extend

at least three frame spaces. It is
desirable to fit all stanchions above
the longitudinal girders in a ship's
bottom known as "keelsons".

Shallow draft hulls have the stanch-
ions on frames in the longitudinal
trusses. Bracket plates connect the
stanchions to the upper and lower
chord shapes and to the diagonal
angle braces.

to an angle clip by
a vertical palm
similar to the head
here shown. If the
deck beam is of
channel section the
stanchion head may
have a horizon-
tal palm as in the
heel here shown.
The objection to
closely spaced
stanchions is the
degree of obstruc-
tion to cargo stow-
age which they in-
troduce. Widely
spaced stanchions
of tubular or oth-
er sections (Fig.
S5-b-c-d-e) are now
fitted to most ves-
sels carrying hold cargoes. Longitu-
dinal and transverse bracket plates
connect the heads to the beam girders
and deck beams (Fig. SSb) ; while
the heels are bracketed to foundations
on the inner bottom plating or the floor
tops (Fig. 55). In the latter case, brack-
ets clii)ped to the reverse frames afford
double angle connection to tlie floors

thrusts are taken at the ends which spaced "hold beams" which tie the

in this case are tne relatively fle.vible ship's sides together and end on

.ship's sides. Camber is now em- "stringers" or heavy longitudinal side

ployed for drainage purposes only, girders. Strong vertical and hori-

but since a ship is very seldom on zontal brackets are fitted at hold

an even keel. ^ en this is scarcely beam ends to these stringers and to

warranted, since the water often ac- web frames which should coincide in

cumulates on the high side of deck spacing with the hold beams. Hold

houses and coamings amidships. beams are usually built up of a plate

Flat deck beams or those with with double upper and lower angles

straight ridged sides rounded at the or of two channels back to back,

center line, are becoming widely used. The long length of beams in pro-

CHAPTER VIII

Design of Longitudinal Framing

^^^^^HE principal strains set up in
m C^\ ordinary vessels are longitu-
^ J dinal in character and can be

^^^^ best understood if it is as-
sumed that a wave of the vessel's length
has its crests at the bow and stern ; or
this same wave has a crest amidships and
a trough at the bow and stern.

The length of a wave is measured be-
tween the highest points of two suc-
cessive crests or the low points of two
successive troughs. The height of a
wave is the vertical distance between
the lowest point of a trough and the
highest point of a crest. This height
is taken as one-twentieth of the wave
length, so that a 100-foot wave would
be 5 feet high. The profile of a wave
is -a curve called a "trochoid," gener-
ated by a point on the circumference
of a rolling circle.

Wave Action Causes Strain

When the vessel's water line has a
wavy contour, the maximum longitu-
dinal strains are set up in the vessel by
a wave of its length. Where the crests
are at the bow and

the keel. The cross section of the ves-
sel is that of an equivalent girder and
the longitudinal bending strains can be
taken only by the hull planking or plat-
ing and such longitudinal framing as
may be fitted.

When the wave crest is amidships,
the deck tends to hog and the bow
and stern to sag. Tension is here set
up in the deck and compression at the
keel. In either case the midship section
is that most greatly strained and the
change from tension at the top to
compression at the bottom, or vice
versa, is gradually reduced from maxi-
mum intensity at the extreme top and
bottom to zero at a point about halfway
between the keel and the deck. The
plane of zero stress is called the neutral
axis.

If the moment of inertia of the
midship section were calculated about
the neutral axis and the greatest bending
moment for hogging and for sagging
were derived from curves showing the
longitudinal distribution of hull weight
and buoyancy, the stress in the ex-

stern and the
trough is amid-
ships it will be
seen that displace-
ment is concentrat-
ed at the ends and
lacking amidships.
Since the vessel's
weight is greater at
midlength due to
the machinery and
cargo, the tendency
would be for the
unsupported middle
body to sag. The
hull in this case
resembles a beam
supported at the
ends and with a
downward load
midway between
the supports. This
sets up compres-
sive strains tending
to crumple the deck
and tensile strains
tending to stretch

S+ern

,Hull Plank

Stem

/Tmniverie Frames
Widely &i>Aced.

Ofiok Lc»n<)i+i/el/r»al4-

BoTtom l.onO)ifud\na\6

FIG. 56-

LONGITUDINAL STRINGERS AND SHELVES FOR WOODEN TUGS AND
FRAMES FOR SHALLOW STEEL VESSELS

treme deck and keel structure could be
calculated from the well known formula :
SI

M equals

c
where M is the bending moment in foot
pounds or tons.
6" is the stress in pounds or tons

per square inch.
/ is the rectangular moment of
inertia of the midship sec-
tion.
c is the vertical distance from
neutral axis to upper edge
of deck or lower edge ©f
keel.

Strength of Framing Defined

Ordinarily it is not necessary to per-
form this complicated and extensive
calculation for strength, since the ex-
periences of years have established the
proper sizes and disposition of the hull
structure. For steel vessels this has
been particularly well accomplished by
the large marine insurance societies such
as the American Bureau of Shipping,
Lloyd's Register of Shipping, The
Bureau Veritas, etc.
Here the various
structural members
are tabulated ac-
cording to the di-
mensions of the
vessel and if these
are known it is a
simple process to
select the proper
scantlings. Large
wooden vessels
have been similarly
tabulated but not so
thoroughly, since
wood as a ship mar-
terial has been so
broadly replaced by
steel. In smaller
vessels the reverse
is true and wood
will doubtless con-
tinue the material
composing hulls less
than 100 feet long.
At the conclusion
of these chapters
a tabular scantling

Comityoofiort.

The Desian and Cotistrurtiou of Power Work Boats

table for commercial power boats will be
appended and duly explained, with a
view to facilitating the construction of
commercial power boats.

If the above theory held in practice,
the longitudinal framing would be
strongest on the vessel's bottom and
at the deck and little or none would be
needed at the sides. This is not quite
true in practice because the vessel may
be subjected to hogging and sagging
stresses whole it is rolled over at an
angle. The sides would here contribute
toward resisting the longitudinal strains
and even disregarding this condition it
is necessary to reinforce the ordinary
transverse frames by side longitudinals
to withstand the local bending intro-
duced when striking or rubbing against
docks or other vessels.

Keelsons

Longitudinal girders on the vessel's
bottom are termed keelsons and should

arc covered by the false keel. The keel-
son timbers are also bolted together by
vertical bolts between the frames and
by horizontal bolts uniformly spaced to
clear the vertical fastenings.

Notched Keelsons Not Necessary

Sometimes the keelson timbers are
notched over the inner frame edges
with a view to reducing the tendency
to trip in the latter. The added labor
in constructing notched keelsons and
the weakened cross section caused by
cutting away material at the notches
together with the difficulty of obtaining
accurate joints, render it doubtful
wliether this elaborated construction is
justifiable.

In all cases where wooden longi-
tudinals are composed of more than
a single timber and it • is impracticable
to extend these in one length from
stem to stern, the butt scarphs in the
various timbers should be carefully dis-

• rioll y>\ank6eami

FIG. 57— CROSS SFXTTONS LONGITUDTNAI. SHOWING FRAME CONSTRUCTION

extend as far for and aft as possible.
They are ordinarily not more than
8 feet apart at the midship section.
There is usually a center keelson fitted
in conjunction with and directly above
the keel. Side or "sister" keelsons are
between the center keelson and the
lower turn of bilge. "Bilge keelsons"
are at the turn of bilge. "Engine keel-
sons" are fitted under the main engines
and should carry the machinery vibra-
tional strains to the other framing.

Fig. 49 indicates the disposition of
keelsons in a large wooden vessel (from
100 to 300 feet long). The center keel-
son is composed of two or more limbers
side by side and superposed in pyra-
midal fashion. Long vertical bolts pass
through each keelson timber and each
transverse frame, the bolt ends being
riveted over countersunk ring washers.
Those timbers directly above the keel
are vertically bolted to it at each frame
and the countersunk lower bolt heads

posed so tliat no two joints are at or
near the same point. By this means
the loss in longitudinal strength at the
butt joints is not such as to materially
weaken the girder.

Other forms of wooden and steel
center keelsons in vessels with trans-
verse framing were discussed in con-
junction with keels in Chapter V.

Side or sister keelsons are fitted in
large wooden vessels as in Fig. 49.
Where there is but one on each side
of the center line the hold stanchions
should step on it and be connected
thereto with natural crook timber knees
or forged metal brackets. Where prac-
ticable the side keelsons should form
part of the engine foundation framing,
particularly in small vessels. If the
alignment of the engine bed casting
does not conform with the top of the
continuous side keelsons, auxiliary tim-
bers of proper shape and dimensions
should be bolted on top of the keelsons

to receive the engine, or should rest on
the tops of transverse framing imme-
diately alongside the side keelsons, be-
ing side bolted thereto.

Engine Keelsons Should be Long

When it is not practicable to incor-
porate the side keelsons with the engine
keelsons, the latter should be of con-
siderable length. The timbers to which
the engine is bolted are usually too
close together to pass the large flywheel
of most internal combustion engines.
For this reason these local timbers are
bolted to and inboard of a keelson
on each side and the difficulty of pass-
ing the flywheel is obviated by the
thickness of the foundation timbers.

If it is not feasible to extend the
engine keelsons all fore and aft they
may butt against forged angle collars
on the forward and after engine room
bulkheads, particularly if these are of
steel.

It is not customary to fit more than
than one side keelson in large wooden
vessels, since the ceiling timbers on
the inside of transverse frames from
the center line to the bilge are made
extra heavy. Care should be taken to
stagger the end joints of adjacent and
neighboring ceiling timbers in the same
way as for center and side keelsons,
in order that no serious local weakening
may result.

Steel side keelsons, one or more in
number, are fitted in transversely framed
vessels as in Fig. 58 (a) to (c). They
consist of continuous longitudinal steel
shapes on the floor tops, with or without
intercostal plates extending between the
floors to the sheel plating. Types (a),
(b) and (c) are fitted in large vessels.
They consist of continuous angles, bulb
angles or a built up girder connected
to the floor tops by a reverse bar clip
having at least three rivets. The inter-
costal plates have their upper edges
riveted between the continuous keelson
angles and are notched to permit pass-
age of the frame, reverse frame and
reverse slip. A vertical clip joins the
intercostal plates to each floor while
lightening holes may be cut to save
weight.

Bilge keelsons are usually part of
the heavy bottom ceiling timbers in
large wooden vessels (Fig. SO). Small
wooden vessels usually have two or
more square bilge keelsons sprung into
place and through bolted to the frames
(Fig. 49).

Steel bilge keelsons consist of two
angles or bulb angles fitted back to
back on the inner edges of transverse
framing at the bilges. (Fig. 52 (c) and
(d).

Steel engine keelsons (Fig. S3) are
longitudinal plate girders on tops of
the floor plates, with angles at the
lower edges riveted to the reverse

Dcshiit of Longitudinal Framing

frames. The engine base is bolted to
continuous angles on the upper edges
of the engine keelsons.

Where possible, as in the case of
wooden vessels, one of the engine keel-
sons should merge into a side keelson,
the keelson plate being deepened locally
to the proper height for receiving the
engine base. Transverse brackets clipped
to the keelson plates and the reverse
frames should support the engine girders
at each frame.

Keelsons in shallow draft vessels con-
sist of the lower truss chords previ-
ously described (Fig. 51 and 54) and
the bilge log or the bilge angle.

Stringers

All longitudinal girders on the ves-
sel's side above the bilge are covered
by the term "stringers". The location
determines the nomenclature of each
stringer, so that :

(a) Hold stringers are those between
the bilge and the lowest deck.

(b) Stringers at sides of decks or
on tiers of beams in the hold are
called "uper deck stringers", "lower
deck stringers", "hold beam stringers",
etc.

(d) Short stringers at the vessel's
ends are called "panting stringers".

Large wooden vessels usually have
heavy ceiling on the inner edges of the
side framing, rendering it necessary
only to fit stringers on top of the deck
beams at their endings on the frames.

Upper deck stringers are sometimes
called "margin planks" and are fitted
to wooden vessels. If the frames extend
through the stringer to form bulwark
stanchions, a continuous stringer timber
is fitted inboard of a notched margin
plank fitting closely around and be-
tween the frame heads. This notched
plank may be dispensed with by fitting
filling blocks between the frame heads
and the continuous stringers inboard
of these. When the frames do not pierce
the weather deck, tlie rail is on top
of the continuous margin plank.

Lower deck stringers in wooden con-
struction consist of one or more con-
tinuous timbers, side by side or one
above the other such as the hold beam
stringer.

Side stringers may lie fitted in line
with the lower fender with through
bolts thereto.

All wooden stringers should be se-
curely through bolted to every frame
and to the beams on which they lie.
The vertical bolts should pass through
shelf timbers if these are fitted under
the 1)eams. Timbers should be in long

lengths with scarphs in adjacent tiniljers
widely separated.

Clamps

Clamps are heavy timbers on the
inner edges of frames under the end-
ings of beams. They may be of a

Continuous
Ke«lson San.

"R'derTld-tS

frame edges, to which they are securely
joined, with short angle clips in addi-
tion to the reverse frame angles. An
intercostal plate may fit between the
stringer angles and between the frames
to the shell plating where an intercostal
clip secures its outer edge.

Su'a Kcclbois It
- Double Bo1t{jm„.

lrtn»r "Bottom^

- .n\erc06ja\
KeeUon Tlati

nTe.rU)>ta\ SViell flntjle''
(.<») CW CCJ

, WatertKiVit or/ ^BracV:eTF'loor'

FIG. 58— STEEL SIDE KEELSONS WITH TRANSVERSE FRAMING

single plank with its long side vertical
and notched under the beam. Or sev-
eral timbers may be used. Through
bolts should be used transversely
through clamps and frames or vertical-
ly through clamps and beams.

One or more timbers under beam
ends may be fitted inboard of clamps
and are called the "shelf". Tliese assist
in tying the beams to the frames and
are through bolted to both.

The forward and after endings of
stringers, clamps and shelves should be
as in Fig. 56, with overlapped termina-
tions to breast hooks or to filling blocks
between the deck beams and to the
stem logs.

Steel deck stringers are heavy hori-
zontal plates at the sides and securely
riveted to ends of deck beams. A
continuous outer angle connects these
stringer plates to the shell plating.
In lower decks the frames usually
pass up through slots in the outer edge
of the stringer plate and the continuous
stringer angle is fitted along the inner
frame edges, being riveted to the
stringer plate and to the reverse frame.

Good practice calls for side stringers
at least every 8 feet and this may
require additional short stringers in
overhung sterns, where the extreme
slope of the ship's sides creates ex-
cessive length of unsupported side
framing between decks.

Panting stringers are fitted at the bow
between the endings of continuous side
stringers. Heavy breast hooks or bracket
plates connect the ends of these at the
stem. These panting stringers serve to
reinforce the fine forward hull against
the heavy local strains set up by en-
countering waves.

Cartings

Wherever it is necessary to cut hatches
or other large openings in the decks
so that the beams must be cut, a seri-
ous loss of deck strength results. It
is necessary to compensate for the
weakness so caused by butting the
short cut beams on longitudinal girders
which span I)ctween the intact beams
at tlie ends of the hatch or opening.
In wooden vessels these longitudinal
girders are called "carlings".

. Hatch
Cover

• Meldine)

IJ«elcMart)iii'PJuHle

-Fencer

ShetrT\<\nk

Outside
Tiankinj

Coaming T'late-'

FK;. 59— HATCH AND COCKPIT COAMING CONSTRl'CTION

The space between frames, stringer angle
and shell plating, should be filled with
cement or by a tightly fitted wooden
block.

Between deck or hold, stringers of
steel may lie of two angles or bulb
angles fitted liack to back on the inner

Carlings are heavy strong timbers,
always in one length and should always
l)e supported by stanchions at their
ends. When more than 10 feet long,
an extra stanchion should support each
carling midway between the ends. These
stanchions should have heavy timber

The Design avd Construction of Power Work Boats

knees to the carliiig and the beam at
their heads. The short deck beams
should be morticed to the carlings at
their inljoard ends. Heavy horizontal
timber knees should connect the ends
of carlings to the beam at ends of the
opening against which they butt. Natur-
ally these knees should not ordinarily
obstruct the hatch opening but should
be fitted on the outboard side of car-
lings under the deck planking. All
connections where possible, should be
through bolted.

Coamings and Sills — Wood

The edges of all deck openings should
have heavy coaming timbers fitted above
the carlings and deck beams at ends.
These coamings reinforce the carlings
and prevent wash of considerable mois-
ture into the hatches. They are rab-

Lonq

itwdmal Wamma V^'''*' •Single ■BaHbn

"Bee
ftuf

ForTank Vessels.
Suitable For Ordina.-M ■&^\\! Ca<-il<i Ul'\Ms
'^ut^. Of P».Uoni S^n ■Bet-u.^f -1 Tr.r.«y«r«
>cirtini f€ilini U LB»ttem fff H»U.)

TVansvaoc f^raff\c.

employed in smaller fishing boats, the
coaming may be a continuous heavy
oak plank extending above the deck
as in Fig. 59c. This is securely bolted
to a carling which fits between the
coaming and the inner edges of the
frames. A heavy cap rail may be let
over the upper edge of the coaming
plank and a ]4 round molding is fitted
at the junction of coaming with deck
planking.

Steel hatch coamings are shown in
cross section by Fig. 59 (a and b). The
upper edges are fitted with angles or
a special steel molding in which the
wooden hatch covers rest. Steel hatch
covers will be later taken up. The ends
of cut deck beams are clipped to the
coaming plate, as shown, and a margin
plate is fitted on deck all around the
hatch opening. This margin plate is

lb)

WiTh Double Botfortl-

FIG. 60— CROSS SECTION OF A TUG WITH LONGlTtJDINAL FRAMING

beted at their upper inner edges to
receive hatch covers and are fitted with
lugs to support the ends of portable
hatch girders under these covers.
Coamings should be through bolted to
the carlings.

When carlings are fitted below the
lower edges of deck beams, heavy fill-
ing pieces should be fitted between the
ends of deck beams which extend over
the carling. This provides solid timber
between the carling and the coaming
or lower deck house sill which rests
on top of the inboard beam ends.

All through bolts in wood construc-
tion should pass through solid timber,
for if there were a space between the
timbers in which the bolt heads are
embedded, the two timbers would spring
when the bolt was tightened.

Cockpits in Small Boats
With wide open cockpits such as are

connected to the coaming plate by the
riveted coaming angle.

The lower edge of coaming plates
should be fitted with angles or chan-
nels to form a stiff girder at the sides
of the hatch. Sometimes this lower
edge of coaming plate is flanged over,
as in Fig. 59b.

Deck girders over the heads of
stanchions and supporting the deck beams
are fitted of wood or steel if the
stanchions are widely spaced. Shallow
draft hulls which are not deep enough
to be rigid have longitudinal trusses
in the holds. These consist of a con-
tinuous lower girder or chord on the
bottom, and upper chord under the
deckbeams and stanchions between these
chords at intervals of from 3 to 6 feet.
Diagonal braces extend from the foot
of one stanchion to the head of the
next in zig-zag manner. These hold

trusses may be wooden or of steel
angles and bracket plates.

Longitudinal Frames — Wood

The fitting of most of the internal
hull framing in a fore and aft direction
is becoming very popular and properly
so. In light pleasure boats these longi-
tudinals are peculiarly desirable with
"V" bottom hulls. This is because the
relatively slight curvature of any cross
section permits the use of wide planks
and light longitudinals are fitted over
each longitudinal plank seam.

In power workboats with shipshaped
hulls it is impracticable to fit planks
wide enough to allow for sufficiently
heavy longitudinal frames at each seam.
To lighten the frames in keeping with
the plank width should not be attempted
without study. Fig. 57 (a) and (b)
shows the application of heavy longi-
tudinal framing to workboats. Trans-
verse frames at intervals of from 4 to
8 feet are fitted inside the longitudinal
frames which are spaced from 12 to 18
inches apart. It is necessary to fit
filling pieces between the hull plank and
the widely spaced transverses, so that the
plank seams between longitudinals are
properly supported.

It would be simpler to run the hull
planking transversely or diagonally
across the longitudinal frames as is
done in some barge construction. This
is not recommended for vessels which
are self-propelled unless the bottom is
sheathed with metal, because the rough-
ness of the surface is increased with
respect to the direction of travel and
more power is lost in skin frictional
resistance.

Longitudinal steel framing is not used
in vessels of smaller sizes, but has
been considerably employed in barges
and box-shaped hulls. In steel ship-
building this is known as the "Isher-
wood" system, having been patented
under that name.

Fig. 60 is the cross section of a tug
built on the longitudinal system of
framing. Continuous bulb angles spaced
from 20 to 27 inches apart extend fore
and aft on the inside of the shell
plating and under the deck. At the ves-
sel's ends where the girth of section
is less than amidships, it is necessary to
stop some of the longitudinals at the
peak bulkheads to which they should be
bracketed. It is common to stop all
longitudinals at these peak bulkheads
and to substitute ordinary transverse
framing from these points to the stem
and stern, respectively.

Heavy transverses which are merely
web frames spaced from 10 to 12 feet
apart, are fitted as in Fig. 60 to resist
transverse and local stresses.

CHAPTER IX

Bulkheads Demand Careful Planning

'LL vertical partitions in a ves-
sel are called "bulkheads."
They are what correspond to
the interior walls in an ordi-
nary house. They are classified accord-
ing to their strength and purpose as :

(a) Structural: Non watertight,
watertight, oil tight.

(b) Divisional, partitions, etc.

Bulkheads running across the ship
are called "transverse" and those ex-
tending fore and aft are "longitudinal
bulkheads."

Steel or wood may be used in bulk-
head construction. Watertight bulk-
heads are fitted in the holds of most
vessels, their object being to minimize
the danger of sinkage by confining
the seawater to any compartment in
which the hull may be damaged by
collision, grounding or other accident.
Transverse bulkheads are most effec-
tive for this purpose. Tanks contain-
ing fresh water, water ballast or for
fish preservation in trawlers are also
fitted with watertight bulkheads. The
number of watertight bulkheads in-
stalled varies with the size and type
of vessel.

The Collision Bulkhead

Nearly all vessels have one trans-
verse watertight bulkhead called the
"collision" or "forepeak" bulkhead.
This is fitted near the bow and should
be on a transverse frame. In large
vessels the distance abaft the stem is
one-twentieth of the vessel's length,
but in vessels less than 125 feet long
this distance is greater (from one-
eighth to one-si.xteenth of the length).

There is also a watertight bulk-
head at each end of the machinery
space and usually enclosing compart-
ments in which fuel is carried in
separate tanks. When (in the case of
steel vessels) the fuel tanks are part
of the hull, the bounding bulkheads
must be of especially tight construc-
tion to prevent leakage.

In a previous article the need of
reserve buoyancy and the purpose of
bulkheads was demonstrated by as-
suming that a central compartment
of a box shaped hull was punctured
and that the bulkheads in this com-
partment prevented the inrushing

water from flooding the entire hold.
The vessel then sank until the volume
of water which the damaged compart-
ment had originally displaced, was re-
gained by the intact parts of the hull
on each side of the damaged compart-
ment. The symmetry of the regained
buoyant volumes caused the vessel to
settle parallel to her original water
plane.

Fig. 61 shows what occurs to a
vessel when damaged in the more
usual and less favorable manner of
having a compartment near the bow
or stern torn open to the sea.

Suppose that the water plane
(VV-L) is that at which the vessel
floated before the compartment
(RSTV) was damaged. The point
(B) will represent the center of
buoyancy of the original underwater
volume (DEFV) and the point (G)
is the center of gravity of the vessel's
structure and contents. These two
points are located on the axis (X-X)
which is perpendicular to the original
water line (W-L). Now when the
sea water enters compartment
(RSTV), the displaced volume is de-
creased by the portion (HFTV), and
the vessel may be assumed to settle
to the water line (w-1), which is
parallel to (WL). The volume
(OliPH) between these water planes
must equal the lost displacement
(HFTV) and the new intact under-
water volume is (ODRT). The point
(B') halfway between the bulkhead
RT and the end OD is the center
of buoyancy of this new imderwater
volume and it is to the left of the
original center (B). If the vessel
floated at (w 1) after damage as
assumed, the force of buoyancy would
act through the point B' and upward
on the line (y-y) which is perpendicu-
lar to the line (w-1). The vessel's
weight would act downward through
the center of gravity (G) and along
the line (x-x). This line is also per-
pendicular to the line (w 1) so that
we would have two equal forces act-
ing in opposite directions as shown
and separated from each other by the
distance (h) between (x-x) and (y-y).
These two forces form what is called
a couple and would tend to rotate the
vessel in the direction taken by the

hands of a clock (called clockwise).
It will also be seen that when these
two forces act in the same straight
line there will no longer be a tend-
ency to rotate the vessel and since
the forces are equal but opposite, the
vessel will then come to rest.

Accordingly let W'L' be the in-
clined water plane to which the vessel
will incline or "trim" when the forces
of buoyancy and the vessel's weight
are again vertically in the same
straight line (z-z). The final under-
water volume (ARTD) will equal the
original displaced volume (EFVD)
and (B") is the final center of
buoyancy.

It is possible to calculate the posi-
tion of the inclined water plane
(W'L') and consequently the effect
upon the vessel of flooding any com-
partment. This calculation is involved
and of too great length to be con-
sidered here. For a complete dis-
course on this subject refer to Att-
wood's text book on "The Theoreti-
cal Naval Architecture" or to Biles'
"Design and Construction of Ships."

Notice that the freeboard is less
at the damaged than at the intact end
of the vessel and that the draft S V
is greater at the damaged end than
the draft A D at the other end.

The quality which a vessel has of
inclining in the above manner is
known as "changing trim." The dif-
ference in feet and inches between the
draft S V at the low end and A D
at the high end is called the "change
of trim" and is equal to the sum of
F S and A E. But F S and A E arc
the changes in draft from the original
water line W L to the new water
line W' L'. Therefore, the "change
of trim" is equal to the sum of the
changes in draft at the forward and
after ends of the vessel. Change of
trim may be produced by moving a
weight from its position on the
vessel, to a point nearer the bow or
stern. The weight which must move
one foot to cause a change of one
inch in trim, is called the moment to
change trim one inch.

Large ships are so designed that if
two adjacent hold compartments
should be flooded, the change of trim
will not be excessive and the vessel

The Design and Construction of Poivcr Work Boats

FIG. 61— WHAT HAPPENS WHEN THE BOW OR STERN COMPARTMENT IS

FLOODED

will float, or if three remote com-
partments are flooded the vessel will
not sink.

Small vessels can with difficulty be
made to conform to such require-
ments, since the increased number of
bulkheads necessary would make the
hold compartments too small to carry
cargo economically.

Again, wooden bulkheads or steel
bulkheads in wooden hulls cannot be
made absolutely watertight in case of
hull damage. This is because the
seams of the hull planks would
ordinarily "start" for some distance
on each side of the point of impact,
permitting the water to leak around
the margin of the bulkheads to the
other compartments.

Bulkheads serve to retard the leak-
age and to save the vessel if action is
quickly taken and the pumps have
sufficient capacity to discharge the

water as it leaks in. Steel bulkheads
in steel vessels can be made water-
tight, but do not necessarily make the
vessel "nonsinkable." This term is
a fond dream concocted in the fertile
imagination of laymen.

In very small vessels such as life-
boats where the holds are not used
to carry cargo, watertight metal tanks
are sometimes built into the hold
compartments and they afford suffi-
cient buoyancy to float the boat if the
exterior hull is damaged. If these
tanks are also punctured, their utility
ceases and the boat will sink.

Wooden Bulkheads

Fig. 62 is a transverse watertight
bulkhead in the hold of a wooden
vessel longer than 125 feet. The
ceiling which contributes to the
longitudinal strength of the vessel,
should not be cut at the bulkhead

JBi

^S3 — ^

Tran6\/erse 6ect'»on

Loncfifuciincil Elevation.

FIG. 62— TRANSVERSE WATERTIGHT BULKHEAD OF WOODEN VESSEL
LONGER THAN 125 FEET

which fits closely inside of the in-
ternal longitudinal hull timbers. Two
thicknesses of tongue and groove
planks with a layer of canvas in thick
white lead, tar or paint between them,
form the bulkhead proper. The seams
of these two thicknesses of planking
are at right angles to each other, one
set running vertically and the other
horizontally; or both sets being at
complementary angles of 45 degrees
to the vertical ship's center line.

The bulkhead planks are through
bolted between two deck beams at
their tops and between heavy bulk-
head margin timbers all around their
edges. Canvas strips thickly coated
with thick lead and called stop waters,
are fitted between the bulkhead plank-
ing and the margin timbers. In very
heavy construction all the bulkhead
planking and margin seams should
be calked, particularly if one of the
compartments is to form a permanent
water tank.

A steel angle iron properly forged
to fit closely around the bulkhead
edges may be substituted for the mar-
gin timbers and canvas stop waters or
calking should also be used in the
seams where the bounding angle fits
against the bulkhead planking and the
longitudinal ceiling.

Heavy stiffening timbers should re-
enforce the bulkhead plank on each
side. They should be spaced about
four feet apart and should be logs
whose square section is at least four
times the bulkhead thickness. The
stiflfeners extend vertically on one
side and horizontally on the other
side of the bulkhead. Heavy natural
crook timber knees or forged metal
brackets connect the ends of bulk-
head stiffeners to the deck and ceil-
ing. Where practicable, stiffeners
should terminate on keelsons and
stringers.

The thickness of bulkhead planking
for the above construction varies
from one-half inch for each layer (one
inch total thickness) in small boats
(30 to SO feet long); to four inches
for each layer (eight inches total
thickness) in vessels 325 feet long.

These larger bulkheads may be con-
structed of one thickness of six to
eight-inch planking, calked on both
sides, but the strength and tightness
are not equal to those obtained with
the double layers at riglit angles to
each other.

Transverse Watertight Bulkheads

The transverse watertight bulkheads
of small vessels in which the ceiling
planks are not fitted for strength,
may be constructed as in Fig. 63. In
this case the only longitudinal fram-
ing which passes through the bulk-
l-.ead consists of keelsons, stringers.

Bulkheads Demand Careful Planniiig

clamps and shelf logs. The bulkhead
planks extend out to the hull plank-
ing with double frames and beams
forming the margin logs. Canvas stop
waters are bolted between the bulk-
head planking and the marginal fram-
ing. Steel angle bar staples are
forged to fit around the longitudinals
which pass through the bulkheads.

In this connection it may be re-
marked that watertight bulkheads
were not fitted in holds during the
period when wooden ships were pre-
dominant.

Longitudinal watertight bulkheads
of wood are not often fitted. The
construction is identical with that for
transverse bulkheads when they are
used.

Engine Bulkheads Fireproof

It is desirable to render bulkheads
in the engine room fire resisting and
this is accomplished by covering the
side toward the engine room with a
layer of asbestos mill board or other
insulator. Galvanized sheet iron is
tacked over this insulation. Yellow
pine or fir planks are used for water-
tight bulkheads.

Divisional or minor wooden bulk-
heads serve to divide the interior of
vessels into the various compartments
for berthing, messing, storage, etc.
They may be longitudinal or trans-
verse and built of vertically staved
tongue and grooved planks, panels or
composition wallboard tacked over
wooden staves.

When extending athwartships it is
desirable that they fit against a trans-
verse deck beam (Fig. 64-a). The
lower ends of bulkhead stavings are
set into a grooved sill as shown and
the planks driven home then blind
nailed at top and bottom. If the
height is more than seven feet (un-
supported planks) and the thickness
is less than one inch, an intermediate
horizontal studding should be fitted
between vertical stiff eners of 2 x 4-inch
timber spaced not more than four
feet apart.

This same reasoning applies to
panels (Fig. 64-f), but the studding
should be lighter and the paneling be
fitted on both sides thereof (Fig
64-k).

Bulkheads In the Cabins

Divisional longitudinal bulkheads in
living spaces extend to a scantling
which is grooved to receive the bulk-
head sheathing and is fitted under the
transverse deck beams (Fig. 64-b).
This leaves an open space for ventila-
tion between the top of the bulkhead
and the deck above. This space may
be left open or fitted with a grill of
wood or metal.

Galleys, pantries, baths and toilet

■^c^^'^''

Vertical STif^ENCR.

SlOe JTRtN&«R.

BuuKHEftD ■pLANlCINtr,

t 1 1^ Sr«pi.E flwaiUE.

Jk ll£l \.l<&ELi.ON'

Keeu

PlTHW/^ieTSHlP View LON&ITi^DIVrtL El^vAT'ON.

FIG. 63-TRANSVERSE WATERTIGHT BULKHEAD FOR SMALL WOODEN VESSEL

spaces should be completely shut oflf
from the other compartments by ex-
tending the longitudinal bulkhead
sheathing between the beams to the
deck or cabin top overhead as in Fig.
64-c. A quarter round or other mold-
ing is neatly fitted around each beam.

Galvanized sheet iron, zinc or lead
should line the bulkheads in shower
or bath compartments to protect the
wood from the splash. Tongue and
groove bulkheads may be of V cham-
fered or of beaded planks (Figures
64-d and e respectively) and vary in
thickness from ^-inch to IJ^-inch.

Bulkheads of composition wallboard
in combination with staving are
shown in Fig. 64-g and h. The wall-
board varies from 3/16 inch to S/16-
inch in thickness and the sheets are
securely tacked to the staving. A
molding strip is nailed over the wall-
board seams and may be of stained
wood, thus affording a paneled affect.
When the staving is solid as in Fig.
64-g, the thinner wallboard is em-
ployed, but heavy board should be

used with widely spaced staving (Fig.
64-h). These staves are from J^-inch
to lJ4-inch thick and from 3 to 4
inches wide. A clear space of from
two to four inches may be allowed
between staves.

Divisional bulkheads may be fitted
in the deck houses and superstructure
of steel vessels. The construction is
the same as in the case of wooden
boats and the object of using wood is
to lighten the minor bulkheads, thus
reducing the total structural weight
and gaining carrying capacity on a
fixed load displacement.

Steel Bulkheads

These may really be made water-
tight or oil tight in steel vessels and
they are more nearly so than wooden
ones in wooden vessels. The common
practice is to make the bulkheads en-
closing the machinery space of steel,
for fire resisting and to build the
bulkheads in holds outside the engine
room of wood in wooden vessels.

Where continuous inner wooden

[ l-0e«M

tbl

(c)

(d)
m^m^^. iii.,i {fj

T&G- or
Bnel

gfe%^ ^%a ^^ \gmii u^ vm (h)

FIG. 64— CROSS SECTIONS OF VARIOUS MINOR BULKHEADS FOR CABINS, ETC.

The Design end Construction of Power Work Boats

(b)

(c)

Web S>t<f{ener

FIG. 65— STEEL BULKHEADS AND FASTENINGS FOR WOODEN VESSELS

ceiling is fitted for strength of recesses filled with cement or wooden

wooden vessels, the steel bulkheads plugs. These radiating bolts on

fit inside the ceiling (Fig. 65-a) and opposite sides of the bulkhead should

have double steel margin angles, be staggered as shown in (Fig. 6S-a

Sometimes wooden margin timbers and b), to prevent local weakening

are fitted on both sides of the steel of the frames due to material cut

bulkhead plating which is bolted to away. They should also clear the

them. (Fig. 6S-b). bolts or spikes which fasten the hull

Canvas stopwaters in white lead are planking to the transverse frames,

inserted between the margin angles Bulkhead plating in holds varies in

or timbers and the ceiling. Through thickness from 5 pounds per square

bolts spaced between the ones join- foot (J^-inch thick), to IS pounds per

ing the margins to the bulkheads, ex- square foot (5-^-inch thick), the width

tend to the outside of the transverse and depth of bulkhead regulating the

frames, where the bolt heads are thickness,

countersunk over washers and the The number of plates in a bulk-

7T'

mrr

FIG 66-SHOWS METHOD OF FITTING "SHOES" AT BULKHEADS WHERE
KEELSONS AND STRINGERS ARE CUT

head is governed by the maximum
width to which the steel mills can roll
and varies according to the thickness,
width and length of the plate. This
is governed by the size of steel billet
from which the plate is rolled and the
width of the plate rolls.

Use Standard Plates

The steel companies publish tables
stating the standard widths of plates
for each thickness and the layout of
bulkhead plating should be such that
standard plates may be used where
possible. This will reduce wasted ma-
terial and extra expense involved by
sheering and planing the plates.

The seams of bulkhead plating are
lapped and single or double riveted.
The plate edges of seams in water-
tight bulkheads should be planed to a
slight bevel and should be calked after
riveting. Calking of steel plates will
be taken up in connection with shell
plating, as will also riveting. The
scantling tables appended to this
series of articles, sets forth the proper
thickness of steel bulkheads, the size
and spacing of rivets and stiffeners.
Rivet holes in seams should always
be punched from the "faying" surfaces
which are those bearing together at
the seam.

Bulkhead plating is so thin relative
to its depth and width that structural
stifTeners consisting of angle bars,
bulb angles, channels or deep web
plates in conjunction with angles
must be fitted. (Fig. 65-c and d).
These are usually fitted vertically at
intervals of from 18 to 27 inches.

Deep bulkheads have horizontal
stiffeners on the opposite side of plat-
ing to which vertical ones are fitted.
Horizontal stifTeners are spaced about
four feet apart.

Bulkheads In Steel Vessels
Transverse watertight bulkheads in
steel vessels are similar to those in
wooden ones except that the marginal
angles are riveted to the shell plating
and the stifleners are bracketed at
their ends. No stop waters are fitted
and all the angles and rivets are
calked. Fig. 66 is a transverse and
longitudinal elevation of this type of
bulkhead.

Keelsons and stringers may be
cut at the bulkhead and secured there-
to with bracket plates and angle clips
or may pass through openings in the
bulkhead plating and then be made
watertight with forged staple angles
or "shoes" as in Fig. 66. These
alternatives also apply to longitudinal
frames where the vessel is so con-
structed.

Observe that the vertical stiffening
angles are on the side of bulkhead
plating away from that on which the

Bulkheads Demand Careful Planning

plating is joggled for seam laps; that
the vertical seams of bulkhead plates
are located between stiffeners and
that in the case of a vessel with
wooden decks (Fig. 66) a steel deck
plate is fitted under the deck planks
for one beam space on each side of
the bulkhead so that the upper stiflf-
ener brackets may be riveted to it.

Where it is necessary for piping to
pierce watertight bulkheads, a flanged
joint is fitted at the bulkhead plating.

Tank Bulkheads — Steel

Compartments designed to carry
water, oil or other fuels in bulk, re-
quire heavier bulkhead construction
than was the case in those where
safety against sinkage was the main
object of installation, The severe
stresses due to washing of the con-
tents from side to side calls for closer
subdivision so that longitudinal bulk-
heads are usually fitted on the vessel's
center line and "swash bulkheads" are
fitted to cut down the surge of the
fluid.

These swash bulkheads are merely
flanged plates, stiffened vertically and
extending between the ends and sides
of the compartment (Fig. 67-a) or
m.ay be continuous light plates with
large holes cut in them (Fig. 67-b).
Vertical angles about 24 inches apart
stiffen the light swash plates and con-
nect them to the watertight bulkheads
at the tank ends and sides. Swash
bulkheads are spaced from 8 to 12
feet apart.

Longitudinal watertight or oil tight
bulkheads should have their lower
plating formed by deepening the cen-
ter or side keelson plates and these
plates should always be continuous.
All transverse framing on the vessel's
bottom should be cut at the longi-
tudinal bulkhead and connected to it
by bracket plates. Sometimes deck
beams extend through the top of
longitudinal bulkheads and forged
angle stapling is fitted around the
beams to prevent leakage. More
often the beams are cut and bracketed
to the bulkhead, resulting in lessened
expense of construction and ample
strength.

Longitudinal centerline bulkheads
have double angle bars all around
their margins, affording connection to
the keel plate, deck plating and trans-
verse bulkheads against which the
longitudinal bulkhead terminates.

Longitudinal bulkheads forming
wing tanks are located on side keel-
sons and usually have a single large
margin angle.

The lower plating of watertight and
oiltight bulkheads is usually heavier
than the upper strakes because of the
greater pressure imposed on the lower
portion of the bulkhead by the

"hydrostatic head." In any fluid the
pressure increases with the depth and
is equal to the weight of a cubic unit
of the liquid multiplied by the depth
of the surface acted upon below the
surface. Thus the weight of fresh
water is 62.5 pounds per cubic foot
and the pressure on an area one foot
square at a depth of 10 feet below
the water surface would be 10x62.5
or 625 pounds.

Center of Pressure

It is usual to assume that all the
pressure load on a submerged sur-
face is concentrated at a point called
the center of pressure. This is located
on the surface at the level correspond-
ing to the center of gravity of an
area formed by a curve showing the
variation of the pressure load with

.lioiolloiiO

^iOjiOiiO o

the depth. If the surface is rectangu-
lar, the pressure load will be equal
to the pressure per square foot times
the area of a strip one foot wide
whose center is at the depth con-
sidered. By computing the pressure
at successive depths and plotting it
to scale at that depth, a series of
points will result, through which a
curve may be drawn. This curve of
pressures is a straight line since the
widths are constant and the center
of gravity of the triangular area be-
tween the pressure curve and the
bulkhead is two-thirds of the sub-
merged depth below the surface. It
is possible to calculate the strength
of bulkheads, but the assumptions
made require considerable detailed
computations. Ordinarily the thick-
ness of plating and size of stiffeners

=¥==i

r^^

Cej (f)

(hj

FIG. 67— CONSTRUCTION OF TANK BULKHEADS FOR OIL AND WATER;
ALSO METAL BULKHEADS FOR MINOR COMPARTMENTS

The Design and Conslrnclion of Poiver Work Boats

is taken from previous successful
practice.

The vertical stififeners of longi-
tudinal bulkheads are located at each
transverse ship's frame and are of the
same size as those for transverse
bulkheads of the same depth.

Web stiffeners are on every fourth
transverse frame of longitudinal bulk-
heads and on every keelson at trans-
verse bulkheads. These web frames
are formed of a tapered plate secured
to the bulkhead by a vertical angle
and having double face angles on
their vertical outer edges. Flanged
bracket plates connect the lovifcr end
of web stiffener plates to the trans-
verse floor plates and to the deck
plating.

Wing Tank Bulkheads

In deep tanks it is necessary to
support the vertical stiffeners midway
of their depth. This is done in wing
tank bulkheads by angles sprung be-
tween the side stringers and the bulk-
head on alternate frames (Fig. 67-c).
Bracket plates connect these stay
angles to the stiffeners and to the
side stringers if the latter consist of
two shapes on the inside of frames.
If the stringer has a wide shelf plate
as shown in the figure, the stay angle

is riveted directly on top of this
plate.

The intermediate stiffener support
for bulkheads on the ship's center line
and for deep transverse bulkheads, is
provided by a plate shelf as in Fig.
67-a. Brackets support this shelf
from the bulkhead at every stiffener.

Bulkheads in vessels with longi-
tudinal framing have horizontal stiff-
eners at the same level as the hull
side frames and bracketed to these at
their junction. Deep vertical web
stiffeners are at every deep "trans-
verse" at distances of from 8 to 10
feet apart in the tanks.

Minor Steel Bulkheads

Minor compartments may be en-
closed by three types of steel bulk-
heads extending transversely or
longitudinally:

(a) Steel plate.

(b) Deformed steel.

Minor steel plate bulkheads con-
sist (Fig. 67-d) of an upper and lower
coaming plate connected to the decks
by angles. Lighter plating is fitted
between these coamings with vertical
butt seams which are covered with a
wide butt strap as shown. This con-

struction has a paneled appearance on
the side where these seam straps are.
Vertical stiffening angles support
these bulkheads at intervals of three
feet and wooden sheathing or paneling
may be fitted on the stiffener side by
nailing it to furring strips bolted to
tiie stiffeners.

Partitional bulkheads of deformed
steel are shown in Fig. 67-e, f and g,
being composed of galvanized sheet
metal which is corrugated or paneled.
The corrugated types (Fig. 67-e and
f) require no vertical stiffening but
present difficulty in fitting at the
decks. The upper and lower mar-
gins may be of wood or steel angles
and the corrugations are nailed,
riveted or spot welded where they
touch these margin moldings. The
space between the margins and the
hollows of the bulkhead sheathing
may be filled with wood blocks or
with light cement.

Sheet metal panels may be nailed
to wooden framework to form a very
attractive bulkhead (Fig. 67-g).

Spaces requiring ventilation and
light such as galleys, bakeries, etc.,
may be fitted with partitions of heavy
galvanized wire mesh with a metal
frame bolted to angles at the decks.
(Fig. 67-h).

CHAPTER X

Hull Planks — Fenders — Bilge Keels

*'^^^J HE hull planks of wooden ves-
m C^ sels are usually put on with
^ M the longitudinal seams butted,

^^^^ forming a smooth exterior
surface. These are called "carvel"
planked hulls (Figs. 57, 62, 63 and 65).

Small boats are sometimes "clink-
er" built, that is, the longitudinal hull
plank seams are lapped and riveted
together. Clinker built boats are not
caulked and require careful work-
manship to construct properly since
the frames must be notched to fit the
inside of planking.

The more commonly employed car-
vel system of hull planking has all
seams calked with one or more
threads of cotton or oakum, the num-
ber of threads depending upon the
plank thickness. Calking and fasten-
ing of planks will be subsequently
discussed.

One or more planks immediately
next to the keel are made thicker than
the rest of the hull planking and are
called "garboard planks" or simply
"garboards."

Small vessels (up to 50 feet long)
have but one garboard plank from
six to eight inches wide and from
154 inch to 2^/2 inches thick. Vessels
from 50 to 100 feet long have two
garboards from 2j^ to 4j4 inches
thick and from 6 inches to 12 inches
wide. Larger vessels have two or
three garboards up to 6 inches thick.
Occasionally, when two or more gar-
boards are fitted, the plank next the
keel is of maximum thickness and
the second or third garboard has a
thickness between this and that of
the hull planking.

The Garboard Planks

Where oak can be obtained in long
lengths, garboards are of this ma-
terial, but yellow pine and fir are
most often employed. Garboard planks
are rabbeted to the keel as has been
shown and should be edge bolted
thereto if practicable. The ends of
garboard planks if 2 inches or more
thick should be scarphed, the scarph
length being three times the plank
width. Garboard plank ends less than
2 inches thick are butted between
frames, a "butt block" to which the
plank ends are riveted, being fitted

between the frames at the butt. End
butts or scarphs of garboard planks
should be well clear of those on the
neighboring planking, keel and other
longitudinals.

The uppermost hull plank follows
Ihe line of sheer and is sometimes
made of oak. It is usually wider than
the remaining hull planks and is cut
and bevelled to fit the sheer profile.
It is called the sheer plank and is of
the same thickness as the other hull
planking.

Hull planking between the gar-
boards and sheer plank is generally
of imiform thickness (from 54 '"ch
to 5 inches) depending upon size of
vessel. Sometimes in large vessels
the bottom planking is from J4 inch
to 1 inch thicker than the side plank-
ing. The width of these planks

FIG. 68— HOW STEALER PLATES ARE
INTRODUCED.

varies from four to eight inches in
vessels with curved frames. Greater
widths than eight inches are not
employed in this case because it is
difficult to fit the inner surfaces to
the outer edges of the transverse
frames. Thin planks may be steamed
and bent to this transverse curva-
ture but thick planks are slightly
hollowed with an adz, since they tend
to split when bent transversely as
well as fore and aft. Vessels with
straight or slightly curved frames
such as barges and shallow draft craft
have planking up to 12 inches wide,
the objections to transverse bending
being absent.

Tapering the Planks at the Ends

In fitting hull planks they are spaced
off (girthed) on the midship section
and are of maximum width at this

section. The number of planks is then
counted and the girths of several end
sections of the vessel are divided
into the same number of parts. The
planks are tapered to fit fair at or
near these points of division, but
should not be too greatly reduced in
width at the end frames. A minimum
width for the reduced ends of one-
half the midship plank width is good
practice.

Where the girth of end sections is
so much less than the midship section
that excessive reduction in plank
widths would result if the same
number of planks were used at the
vessel's extremeities, the number of
planks may be reduced by fitting one
wide plank at the ends of two narrow
ones. Such a plank is a "stealer" and
is fitted with a butt block covering
the two planks which it replaces.

The extreme forward ends of hull
planking fit into a rabbet on the stem
and the workmanship at this point
should be very accurate. The after
ends of planks in transom sterns cover
the ends of the transom planks and
are fastened to the transom rim log.
A sheet metal flashing is tacked over
the after plank ends at transoms to
protect the ends of wood grain against
wear and decay. In overhung or
fantail sterns where the after plank
ends terminate on the horn timber,
the plank ends are notched to a rab-
bet on that timber, care being taken
that the nibbed ends are not too
nearly a feather edge.

If the planks cannot bend to the
hull form due to the warped nature
of the surface, it is necessary to
"steam" them. This is done by build-
ing a box long enough to take the
longest planks and closing the ends.
The whole is then calked and a steam
pipe introduced at one or both ends
with a drain pipe at the center. After
the planks or other timbers which are
to be bent, have been put into the
box, usually through one end, the
steam is turned on and permitted to
flow until the planks have become
pliable. This time is less for timbers
of small section than for large tim-
bers. A hot water bath may be
used for light planks instead of the
steam box.

The Design and Construction of Pozver Work Boats

Hull planking may be secured to
the framing by:

(a) Screws

(b) Rivets

(d) Bolts

Screws and rivets are used in small
vessels where the plank thickness is
not over two inches. Brass screws
are best and should have heads
countersunk in the planking, the holes
being closed with wooden plugs in
thick white lead. The screws should
extend two-thirds of the way through
the framing.

Copper or galvanized iron rivets
should have their outer ends over

more than eight inches wide have
three.

The butt joints of hull planks should
be between frames and butt blocks
are fitted between the frames at the
plank ends. The plank ends should
be through fastened to the butt blocks
and butt joints should be widely
placed in neighboring planks, to pre-
vent loss of strength in the hull
structure.

Hull Plating

The various methods of fitting hull
plating to the frames are shown in
Figure 68 (a to f). The "in and out"
system of plating (Figure 68 a and
b) is perhaps the most common, the

//, ane/ Oq-<^ ?yQ?^/z^ (■^C^jW.^^/tt^J

/f? arte/ (Put' 7^/dT^f
(^^Stra/ffhT- /-/hens)

^JTcff /e</ 7~ya ?fe^^

CTAnMet 7^a tincf
C TTj Jber ed Z/ners)

FIG. 6S-A— METHODS OF FITTING HULL PLATING TO FRAMES

washers in countersunk holes plugged
as for screws. The inner rivet ends
extend through the frames and are
hammered or clinched over washers.
Galvanized iron spikes with round
heads may be used in very heavy
planking in conjunction with through
bolts. One or two spikes and one
bolt are introduced in each plank
at every frame. The spikes should be
driven in holes drilled slisfhtly smaller
than the spike and the 'ke shank
may be "ragged" or rou^. '.o re-

duce the tendency to w out.

Planks up to eight inches wide have
two fastenings per frame. Those

longitudinal seams being lapped as
shown necessitate that the plates be
fitted in this manner. The frames
may be joggled so that the shell
flanges fit over the staggered shell
plates (a). If the frames are bent to
a fair curve liners must be fitted
between their shell flanges and the
outer hull plates (b).

Joggled hull plates (c) avoid the
use of shell liners with "faired"
frames. Clinker plates (d) are not
extensively used but it is necessary
to employ this system at the vessel's
ends when "stealers" which will be
taken up shortly, are introduced.

Flush plating (e and f) is not
commonly employed. Yachts and
other vessels where the appearance of
plate seams would be undersirable, are
built as in (e).

The lowest "strake" of plating next
to the keel, is the garboard strake and
is sometimes thicker than the other
bottom plating. It is edge lapped to
plate keels and flanged to bar keels.

The uppermost continuous hull plate
against which the upper deck stringer
is fastened, is the "sheer strake." It
is heavier than the lower side plating
and extends above the deck to a
height permitting two rows of rivets
in the sheer strake butt joints to be
above the stringer angle. In large
vessels the strake of plating below
the sheer strake is made heavier than
the remainder of the hull side plating
to the upper turn of bilge. Ordinarily
the side plates from sheer strake to
bilge are of one weight and the bot-
tom plates • from the garboard strake
to the bilge are of one weight,
slightly heavier than the side plating.

Since the greatest tensile and com-
pressive stresses are amidships, the
plating at bow and stern may be
lighter than that for a distance of
one-fourth the vessel's length on each
side of the midship section. Where
severe local stresses are encountered
due to panting at the bow and around
the propeller bossing at the stern,
the hull plating is made the same
thickness as amidships on the same
strake.

If the vessel is to operate in heavy
ice floes doubling plates are fitted at
the bow near the water plane. Doub-
ling plates are also introduced where
openings in the hull entail loss of
strength, such as at large ports or
sea suction and discharge orifices for
machinery piping connections. At the
points where long bridges, forecastles
and poops end, diagonal doubling
plates are fitted to prevent weakness
arising from the sudden loss of ma-
terial in the cross section of the hull.

Where the girthed section of the
hull is so reduced at the bow and
stern that the number of plating
strakes fitted amidships would be-
come very narrow, stealer plates are
introduced to replace two strakes
(Figure 68-g).

Laying Out the Hull Plates

The laying out and ordering of hull
plates is done by arranging the stock
widths as obtained from the plate
tables of the steel company, on the
girth of the midship section. Care
must be taken to include the width
of lapped joints in the width of
strakes. It is undesirable to rivet
more than two thicknesses of metal

Hull Planks — Fenders — Bilge Keels

together because of the difficulty in
making tight rivet connections. For
this reason the shell angles of keel-
sons, tank margins, stringers or other
longitudinal framing should be lo-
cated between the longitudinal seams
of the hull plating.

If the vessel has a flat bottom and
sides, the plating can be ordered
from a drawing called the "shell ex-
pansion." This drawing is made by
"expanding" the transverse frames
at their proper position on the ves-
sel's length and drawing in all frames
(transverse and longitudinal), decks,
keelsons, stringers, bulkheads, margin
angles of double bottoms, bilge keels,
side fender angles, etc. For the length
of the parallel middle body the bot-
tom plates are then drawn in with
their edges parallel to the center of
keel and having the width at the mid-
ship section. The side plates are
drawn in parallel to the expanded
sheer line in the same way. The
girthed frames beyond the parallel
middle body are divided into the
number of equal parts in which there
are plates on the midship section, and
fair lines representing the center line
of longitudinal plate laps are drawn
through the points of division. Steal-
er plates as necessary are introduced
at the extreme ends.

The above shell expansion cannot
be applied in ordinary plates for ves-
sels having the usual shipshaped hull,
because such a hull has a "warped
surface" which means that it cannot
be "expanded" or rolled out onto a
plane. Plates for these vessels are
ordered from a model on which the
shell has been laid out just as it
would appear when fitted in place.
The longitudinal seams of hull
plating are single riveted in small
vessels, double riveted in medium
sized ones and treble riveted in larg-
est ones. Butt joints of hull plates
are double, treble or quadruple riv-
eted. At one quarter of the vessel's
length, from the bow and stern, the
shearing stresses in the hull plating
are maximum, so that in large ves-
sels it is common to introduce an
additional row of rivets in the hull
seams at these localities.

The size and spacing of rivets is
given in riveting rules published by
the American Bureau of Shipping.

Hull rivets usually have counter-
sunk points on the outside, the rivet
filling the hole in the plate and being
slightly convex. The countersinking
extends nearly through the plate. All
rivet holes should be punched from
the faying surface and slightly small-
er than the rivet diameter. The holes
should then be reamed to proper
size for the rivet, the reaming re-

FIG. 69— CONSTRUCTION OF FENDERS AND BILGE KEELS

moving the weakened steel imme-
diately around the punched hole. No
holes in curved or furnaced plates at
the bilge or the stern should be
punched. These holes are drilled after
the plate has been fitted to the hull.
Where two thicknesses of plating are
riveted together, the size of rivet
should be governed by the thicker
plate.

Fenders

All harbor vessels should be fitted
with side fenders to protect the hull
when rubbing against docks or other
vessels. These fenders are construct-
ed of heavy wood securely bolted to
the hull structure and having a flat
or oval facing strip of metal which is
spiked to the fender logs with round
spikes having countersunk heads. The
number of fenders varies with the
freeboard and they are usually from
three to six feet apart.

The upper fender is at or near the
upper deck and follows this deck
from stem to stern. The lower fender
is near the water line at the lowest
point of sheer and is usually parallel

Shelter Dec hed Ve^el-

to the upper fender over that portion
of the hull which is vertical or nearly
so. The lower fender is not neces-
sary at the bow or stern where the
sides overhang to such a degree as
to render it superfluous.

Tugs are an exception to this rule
since they have the lower fender run-
ning to the bow with sometimes an
additional bow fender. Tugs also
have the space between the upper
and lower fenders filled with wood
as in Figure (69-a). This minimizes
the likelihood of damaging the hull
if the fender on a vessel alongside is
between those on the tug. This
crude precaution is improved upon
by "swinging" fenders of hard wood
which are suspended from pad eyes
as in (Figure 69-b). When not in
use these fenders are swung up on
the deck to reduce the resistance
which would be considerable if their
ends dragged in the water. Fenders
of steel with hollow half round sec-
tion may be riveted to the hull (Fig-
ure 69-c). The space between these
steel fenders and the hull may be
empty or filled with cement.

•Shelter X>ecU

C^ai'K-PSJ^^

1
1

)

T— -

,/^/a,Vi DecA

"~|

1
1

'^op

e«/o«e»

foKecA^n-E's.

—. ^

' [

1 ~
1

. 1

1 y

SvAf-rmK aeeir-s

BR/t6ea

/=ijKeea3rt-£-

"TT'r,.,

-<'-i'

(P)

C^J

[cj

(dj

FIG. 70— HOW DECKS ARE CLASSIFIED

The Design and Constntction of Power Work Boats

The degree and period of rolling
in a seaway may be considerably re-
duced by "bilge keels" which serve
as a paddle surface in the direction
of roll. The further these bilge keels
are located from the center about
which the vessel rolls, the greater
will be their effect. Care must be ob-
served that they are far enough under
the bilge curve not to project beyond
the vertical hull sides and thus strike
docks, etc. They must also be far
enough up on the bilge so that their
outer edge is not below the line of
the vessel's bottom. These consid-
erations limit the width of bilge keels,
whose construction is shown in cross
section by Figures 69 a-b-d-e-f and g.
These keels are located at the mid-
dle of the vessel's length and lie in
a diagonal plane. They should co-
incide with the flow of the stream
lines so that they do not introduce
resistance to propulsion. Usually it
is satisfactory to place the bilge keel
in the plane of a bilge diagonal.
Their length is from one-third to
one-half that of the vessel and the
ends should be faired into the hull
surface by a curve which gradually
reduces their width.

Sometimes bilge keels carry away
(are torn loose) in heavy weather or
by striking a submerged obstacle.
For this reason they are attached to
steel hulls with tapped rivets so that
no serious leakage will occur in this
event. If the bilge keels are formed
of a plate attached to angles or tee
bars, the rivet connections to the hull
are stronger than those between the
bilge keel plate and the connecting
bar so that if the plate is torn off

the hull rivets will hold the structural
bar.

Wooden bilge keels and fenders are
usually through bolted to the vessel's
frame and sometimes to clamps,
stringers and bilge keelsons. (Fig.
69-a).

Steel fenders and bilge keels are
riveted to the shell plating and
may be of a single bulb angle or
tee angle (Figure 69 e and f). They
may be formed of a bulb plate con-
nected to the hull by single or double
angles or a tee bar (Figure 69 b and
d). Sometimes a plane plate is em-
ployed, the outer edge of which is
re-enforced with a steel half round
bar on one or both sides (Figure
69-d). Large vessels have bilge keels
formed of two flanged plates with a
stiffening bar at their outer edge and
the space between the plates filled
with yellow pine in pitch or with
cement (Figures 69-g).

Decks may be classified according
to their location as those in the hull
proper and those in the superstructure
above the hull. Their number varies
from one in small vessels, to eight in
the largest. The names of decks vary
with their location and the purpose
which they serve, there never having
been a standardization of the terms
applied. It is becoming popular to
letter or number them in order, from
the topmost down or the reverse. The
confusion in naming decks forming
a part of the hull has not been as
serious as that concerning those in
the superstructure.

Hull decks contribute structural
strength to the vessel, while super-
structure decks are merely light plat-
forms or shelters.

If the vessel's sheer line is con-
tinuous from bow to stern, the up-
per hull deck is made watertight ex-
cept inside of deck houses which may
be built upon it. This upper deck is
usually the most strongly constructed
of them all (Figure 70-b). When the
continuous upper deck is not the main
strength deck, the next deck below
it constitutes the top of the hull
proper. Then the hull sides between the
second or "main" deck are lightened
and merely serve as a shelter to the
space between these two decks. Such
a lightened upper deck is a "shelter,"
"shade," or "awning" deck and is
found in vessels carrying cargo above
the main deck. The freeboard of
such vessels is considered from the
second or main deck to the water
Iilane (Figure 70-a).

Cargo vessels often have "deck erec-
tions" (Figure 70-c) where the hull
sides are extended above the main
deck to produce a "forecastle," "poop"
or "bridge." If these erections (some-
times called islands), are short, they
do not assume the stresses set up in
the hull by hogging or sagging on
the waves, being therefore of rela-
tively light construction. When
longer than one-tenth of the hull
length, however, it is necessary to
strengthen their construction since
the hull stresses are transmitted to
their structure. The depressed spaces
on the main deck included between
the poop, bridge and forecastle, are
termed "wells."

Poop decks are sometimes only half
of the normal deck height of eight
feet above the main deck. Such low-
ered poops (Figure 70-d) are called
quarter decks.

CHAPTER XI

Decks for Wood anci Steel Boats

'LL decks exposed to the weath-
er should be properly drained
and should afford a foothold
when wet. The first of these
results is obtained by fitting drainage
pipes or "scuppers" in gutters or "water-
ways" around the deck margin and by
the introduction of large openings or
"freeing ports" in the bulwarks if the
vessel has these.

Rounding decks up athwartships is
frequently resorted to for drainage
purposes. The round up (called
"camber" or "crown" of the deck)
is a measure of the deck height at
the center line above the level at
the ship's side and a customary de-
termination thereof is one-quarter
inch per foot of deck width at each
point in the length. The deck is
then arched to the arc of a circle
which passes through the points at
each side of the deck and the raised
point on the vessel's center line.
(Fig. 71-a.)

Instead of this rounded form, the
decks may be sloped on each side of
the center line where a circle joining
the sloped sides eliminates the sharp
ridge which would otherwise appear.
(Fig. 71-b.)

Since a vessel is very seldom on
an "even keel" that is perfectly up-
right, and because even with cam-
bered decks the water does not drain
well when the vessel is listed, the
decks may be perfectly flat athwart-
ships. (Fig. 71-c.) This avoids the
expense of sawing or bending wooden
or steel deck beams and affords a
deck which is satisfactory for all
practical purposes.

"Sheer" is the upward curve of the
decks at the bow and stern of a
vessel and is common to most vessels.
The lowest point of the curve show-
ing the deck elevation is called the
"lowest point of sheer" and is located
amidships or else between the mid-
ship section and the stern. (Fig. 71-
d.) The heights of the forward and
after deck end" above the lowest
point of sheer are called the "rise
of sheer forward" and "rise of sheer
aft," respectively. The rise of sheer
is greater at the bow than at the
stern, while the degree of sheer is
greater in small than in large ves-

sels. The lowest point of sheer is
usually between the midship section
and the stern.

IIoiv Sheer Is Determined

Amount of sheer is arbitrarily de-
termined and is governed by

(a) The type of vessel

(b) The appearance

Given a certain depth of hold it is
apparent that the raised forward and
after deck will result in greater free-
board, so that the decks will be
relatively dryer in rough water.
Double ended vessels such as ferry
boats have a "reversed sheer," i. e.,
the deck is higher amidships than at
the ends.

Straight sheer lines (Fig. 71-e and
f) are becoming very common in
vessel design. The principal advan-
tages are (a) simplicity of construc-
tion, (b) increased depth of hold
amidships for a given freeboard at
the bow and the stern. Naval vessels,
power yachts and the famous Eng-
lish "turret deck" ships first em-
ployed straight sheers.

There are three methods of adapt-
ing this design to vessels. The first
is applicable to small vessels oper-
ating in choppy water where more
freeboard is needed forward than aft.
The deck is pitched as in (Fig. 71-e)
and the degree of rise varies from one
foot for every 25 feet of length, down
to one foot in SO feet of leng*h. The
larger pitch applies to shorter ves-
sels.

If the profile of the vessel with
sheer lines the deck is horizontal (Fig.
71-f) and a forecastle is constructed
at the bow. This forecastle may be
from 18 inches to eight feet above
the main deck. The low forecastles
are used in small boats and the ones
of maximum height in larger vessela

If the profile of the vessel with
straight sheer appear inferior to that
with curved, the bulwark rail may
be curved as in (Fig. 71-g) and the
deck made straight.

Wooden Decks

Wooden decks are most frequently
employed in all types of vessels,
mainly because of the good foothold
which they afford when wet. In many

steel vessels the weather deck is of
wood and decks in the hold are of
steel either bare or covered with a
suitable material.

The thickness of deck planking and
method of its installation depend upon
the deck where fitted. If the deck
is a part of the hull and contributes
to the vessel's strength, and if the
traffic on the deck is heavy so that
excessive wear in the deck planking
may be expected, the planks are made
from two to four inches thick. The
width of deck planks varies from 2J^
to 6 inches.

All decking should be laid with the
grain of the wood vertical and wher-
ever planks rest on beams, plates or
other structural members, the bear-
ing surfaces should be painted before
the planks are laid. The plank seams
may be straightened parallel to the
longitudinal center line of the deck,
or they may be curved parallel to the
side of the deck.

The outer boundary of deck plank-
ing is fitted with a wide "margin
plank" against which the deck planks
are butted with "nibbed" ends at the
bow and stern or where curved deck
openings cut the plank seams at an
acute angle. (Fig. 72-a and b.) Planks
laid parallel to the deck side have a
wide "kirig plank" on the center line
against which the plank ends are nib-
bed over wooden butt blocks fitted
underneath.

Material Used for Decks

Yellow pine, white pine, teak, ma-
hogany, oak or fir are the woods
used for decking. Of these the
pines and fir are most general in
commercial vessels. Oak is some-
times used for margin or king planks.
Teak and mahogany are employed in
yacht work.

The lumber should be close grained,
free from knots, checks and other
defects and well seasoned. Planks
should be planed smooth on all four
sides, the vertical edges being slightly
bevelled to allow for calking.

Planks up to IJ^ '"ch thick may be
blind nailed or screwed to the wooden
deck beams, screw heads being count-
ersunk and plugged with wood. Light
wooden decks on steel beams or

The Design and Construction of Poiver Work Boats

Canttri ■

Circular Arc

ifrliji\f I-'"*

La)

Fhf Deck.

Aft-

■i^-

Rise OfShnr Aft.

DecJr CtnUr

Ccj

Ptt* pf SJ>for FhruiarJ

'*- rr0ttcard ^Deck 6 ide

iej

fForve^^f/^

^^T"^

(fj

^--r— '

Sheer^y Bti/utarA ^

~£ i-f;-a,fjf-t Dfciiy"

(3)

FIG. 71— DRAWINGS SHOWING CONTOUK OP DECKS AND SHEER

plating should have wooden nailing
strips bolted to the beams under the
planking.

Decks from two to four inches
have carriage bolts (round headed)
countersunk in the planking with the
nut under the beam. A cotton thread
dipped in white lead is fitted as a
ring under these bolt heads and is
called a "grommet." Deck plugs over
bolt heads should have their grain
parallel to that of the planking and
be dipped in white or red lead.

Planks from 1^ inch up to 4 inches
thick have the seams calked with
from one to three threads of cotton
or oakum, after which the seams are
filled (payed) with pitch or seam
cement. The deck surface is then
planed and sandpapered smooth.

Planks on weather decks less than
1J4 inch thick are of tongue and
grooved material over which canvas

(No. 6 or No. 8) is tacked on thick
paint, marine glue or felt. The can-
vas must be tightly stretched before
tacking with galvanized or copper
tacks and is finally given three coats
of lead paint, the final coat being
buff, gray or other approved color.

Fig. 12) (a to h) shows wooden
deck construction, (a) to (d) being
for superstructure decks, (e) and
(f) for main decks, (g) and (h) for
lower decks and cockpit floors re-
spectively.

The superstructure deck planking is
laid on beams spaced from 15 to 20
inches apart and resting on the house
cap log as shown. The inner house
sheathing or panelling extends be-
tween the beams, filling blocks being
fitted in the space over the cap log.
Lead sheets are tacked on; the can-
vas under all deck fittings, or wooden
blocks may be substituted to protect

,nai-i)ir TUnk

T'/onk ie'rx • Para Hal
■ti (Tenfar i-me.

Planh Ssams Tara/I^
to Veck aTJia'

FIG. 72— METHODS OF LAYING DECK PLANKS

the canvas and prevent cutting it
with the sharp base of the metal
filling. Scuppers are located to drain
these decks.

Main decks (Fig. 12>-^ and f) in
wooden vessels have extra heavy
beams, particularly in tugs or other
vessels which must withstand side
crushing. These beams are from 18
to 24 inches apart and their attach-
ments have been discussed under
stanchions, clamps, shelves and knees.
These decks are always calked water-
tight.

Lower decks (Fig. 73-g) are water-
tight in living spaces but not in
cargo holds. When such lower decks
are very short platforms, they are
called "flats" and may be fitted
locally over hold beams or built up as
separate structures on suitable stan-
chions, carlings and beams only
partly across the hold. Flats in the
engine room may have gratings or
corrugated plating substituted for the
wood planking, or sheet copper ham-
mered rough may serve to protect the
wood against the damage due to
placing heavy machinery parts on the
fiat when conducting repairs. Copper
is not recommended because of the
slippery surface caused by grease.

Linoleum Is Good Covering

Linoleum forms an excellent cov-
ering for hold decks in living quar-
ters since it is warm, easily cleaned
and neat appearing. It varies in thick-
ness (good quality Navy) from %
inch to ]4 inch and should be care-
fully laid at a temperature of about
70 degrees. In unrolling cold linoleum
cracks will develop. The linoleum
should be rolled out flat in the com-
partments where fitted and be allowed
to lie unfastened for several days.
After this it may be cemented or
nailed to the deck (steel or wood)
and no bulges will develop. All
hatches or other deck openings in the
linoleum should be fitted with sheet
brass bounding strips at least }i
inch wide.

The decks in galleys, toilets and
lamp rooms should be cemented and
are usually tiled. In wooden vessels
the deck planks are first covered with
watertight sheet zinc or lead which
is flashed up the bulkheads to a height
of 6 inches. Then from }i inch to
l]4 inch of neat cement mortar is
placed on the metal and finally the
nonporous or glazed tiling is placed
on the cement. The tile is hammered
down level by striking a plank laid
thereon and a thin grouting or cement
wash is applied to fill the cracks be-
tween the tile. It is well to use
rounded tile in the edges formed at
the bulkheads and to carry the tile

Decks for Wood and Steel Boats

up the bulkheads. This permits wash-
ing down the deck. Drainage scup-
pers should always be installed in
cemented or tiled spaces.

Cockpit floors (Fig. 73-h) are be-
low the level of the main deck and
are not usually fitted in vessels more
than 65 feet long. They should
always be at least six inches above
the load water line so that the sea
water can drain freely through scup-
pers if waves should be shipped.
Such cockpits are termed "self bail-
ing." Sometimes ball or flap check
valves are fitted in the scupper pipes
and these prevent the sea water from
flooding the cockpit by washing back
through the drain pipes. A water-
tight base board is installed all
around the edges of cockpit floors to
a height of from six to twelve inches,
while tongue and groove vertical ceil-
ing sheaths the sides of cockpits up
to the main deck. A deep coam-
ing extends all around the cockpit
at the main deck. (Fig. 5>'9^c.)

Decks — Steel Vessels
Steel vessels' decks may be wooden
planking on steel beams, steel plating
on steel beams or composition ce-
ment material on light steel plating.
In (Fig. 74-a to c) the construction
of superstructure decks and decks
on house tops are shown. (a) is
house top with tongue and groove
planks nailed to wooden battens which
are fitted in the bosom of the steel
beam angles. These angles have their
horizontal flanges at their lower
edges and are riveted to margin
plates around the upper deck house
and coaming. The wooden beam strips
are side bolted to the vertical steel
beam flange with countersunk bolts.
The house top overhangs the side
and end house bulkheads and a con-
tinuous molding angle is clipped to
the overhung beam ends. A margin
plank extends around the deck edge
and the canvas covering is lead
flashed to it. The scuppers are close
against the margin plank and their
pipes pass through the overhang to
the deck below.

Fig. 74-(b) shows a house top
which overhangs to the vessel's side,
forming a shelter to the deck below.
The beams of the lower deck house
are similar to those in 74-(a) and
terminate in a steel stringer plate
which is riveted through a stringer
angle to a sheer plate. Stanchions
of pipe, solid round bars, angles or
other structural steel shapes support
this marginal deck girder from the
deck below. Three alternative con-
structions of the margin girder are
shown.

Fig. 74- (c) is a steel house top
with light plating joggled over steel

beams and riveted to them. The
plating is 7.6 pounds to 10.2 pounds
per square foot (3/16 inch to % inch)
in small vessels such as tugs and has
an overhang formed by two angle
bars as shown or by a channel (Fig.
74-d). Sometimes no overhang is
introduced, the house margin being
plain as in Fig. 74-(l) or having the
house side plating extended up to
form a waterway. (Fig. 74-m.) The
house top plating in large vessels may

which a cement or bituminous com-
pound is laid as a substitute for wood.

Decks planked with wood may have
their beams fitted on alternate frames,
the timber being stiff enough to sup-
port itself over the intervening span
with ordinary loads. Steel plated or
cemented decks should have beams on
every frame.

A wide heavy "stringer plate" forms
a marginal girder for all decks in
steel vessels and is connected to the shell

(CV

(h>

(CJ

'■ii^^^///41^i^^9imfimi=^,

r/^^k^^^/y^^^^^^y^^^^■^wiyy/^

(f)

■ 1 r '' f"^ «.^

"v'

FIG. 73— CROSS-SECTION OP WOODEN DECK CONSTRUCTION

be covered with wood planking or a
composition deck cement (Fig. 74-e).
Half round steel molding bars are
usually riveted at deck edges for ap-
pearances as shown in the figures.

Hull decks exposed to the weather
in steel vessels are more strongly
built than the superstructure decks.
They may be composed of steel beams
partially plated over and covered with
wood planking; of steel beams cov-
ered with steel plating; or of steel
beams covered with light plating on

plating by a continuous stringer
angle (Fig. 74 (f) and (g).) In lower
decks where the frames pass up
through the stringer plate, the con-
tinuous stringer angle is fitted in-
side the frames and riveted to the
reverse frame or to a clip on the
frames if these are of bulb angle.
(Fig. 74-h.) Intercostal clips join
the edge of such stringer plates to
the shell plating and the space be-
tween frames outside of the con-
tinuous stringer angle is filled with a

The Design and Construction of Power Work Boats

T?e.moyeD To ihou Sr£e.L Beoms.

'Cunt Beam 6.

D«lc Beams. fl« Ever^ t=1-ar»itf

(•ftnchor
Clip.

^TEEL OecKT-Ti-OTCO.

PIG. 74— CONSTRUCTION OP DECKS OF STEEL VESSELS

wood block, cement or a forged or
a cast shoe of angle section.

Tie plates from six to eight inches
wide are fitted under the deck plank-
ing and serve to connect the deck
sides and ends. Margin plates are
fitted around all deck openings to take
the planking ends and to re-enforce
the locally weakened structure. (Fig.
74-n.) The deck planks are cut to
fit over all deck plates and are bolted
to the deck beams as in the case of
wooden vessels.

Covering for Steel Decks

A waterway angle (Fig. 74-f and
n) is fitted from 9 to 12 inches
inboard of the stringer angle against
the margin plank or the composition
deck covering. The object of fitting
planking or other deck covering over
steel decks is to afford a secure foot-
hold when the decks are wet.

Asphalt cement mortar or numer-
ous patent compositions may be sub-
stituted for planking. If asphalt is

used it should be specified to the
consistency employed in the street
paving of cities in the locality in
which the vessel is to operate. This
will insure good wear and provide
against undue softening in warm
weather.

Bonding clips of flat metal are
bolted or spot welded to the deck
plating before putting on the deck
covering (Fig. 74-p). The thickness
of composition deck covering ,b
from one to two and one-half inches.

Wi'tti Ordii

^baffen

FIG.

ie)

Z)c/it T/a^t Ce/7/'na

73— CONSTRUCTION OP CEILINGS
DOUBLE BOTTOMS

AND

PIG. 75— CONSTRUCTION OF CEILINGS

Steel weather decks are sanded
while the paint is wet to provide a
footing.

Watertight lower decks are fitted
over deep tank tops and are com-
pletely plated over with steel beams
on every frame. Where side deck
margins butt against the hull plating
or steel bulkheads pass through them,
it is necessary to fit a continuous
stapled margin angle around the
frames and the bulkhead stiffeners
(Fig. 74-i). It may be necessary,
particularly if the hull has a slope as
at the stern, to cut the frames or the
bulkhead stiffeners and bracket them
above and below the deck (Fig. 74-
k). In this case a continuous mar-
gin angle passes all around the deck
and the frame; brackets are cut to
clear this angle. These brackets are
at least three times the depth of the
frame or stiflfener angles to which
they are fastened and have their inner
edges flanged.

All steel deck beams except those

Decks for Wood mid Steel Boats

abaft the transom (in overhung
sterns) extend athwartships. The
beam at the frame to which the stern-
post is connected is called the tran-
som beam. Aft of this the beams
radiate (Fig. 74-n and o) to coincide
with the cant frames previously de-
scribed. These "cant beams" are
bracketed to the transom beam and
to the cant frames.

In cargo holds it is necessary to
prevent package freight or bulk solids
from getting between the vertical
floors and keelsons of the ship's
bottom. This is done by building
a wooden platform called a "ceiling"
on the floor tops (Fig. 75-a). Ceiling
timbers are framed together in sec-
tions which can be removed for in-
specting, cleaning or painting the

bilges. The planks do not contribute
strength in steel vessels and are
about two inches thick. If dry bulk
cargo such as grain or coal is car-
ried, the ceiling should be "dust tight"
by building it of two thicknesses of
one inch planks with the seams stag-
gered. Where keelsoms project above
the floor tops in single bottomed
vessels, it is necessary to fit padding
timbers to protect the structure and
cargo from damage.

Ceiling on double bottoms is raised
some two inches above the inner bot-
tom plates by "sleepers" of 2x4
timbers which extend athwartships
and are spaced about four feet apart.
This is to permit moisture on the
inner bottom to drain the bilges
without damaging the cargo. Fill-

ing timbers are fitted between the
frames where the ceiling joins the
hull sides and "cargo battens" are
installed inside the vertical side fram-
ing and on the bulkhead stiffeners in
package or miscellaneous cargo holds.
These battens may be in built up sec-
tions bolted to the reverse frames, in
single strips bolted to the reverse
frames or in single strips supported
by "batten hooks" (Fig. 7S-b). Cargo
battens in steel ships longitudinally
framed are fitted vertically (Fig. 7S-d).
The battens are usually l^x 4-inch
timbers spaced about 6 inches on centers.
Large wooden vessels have perma-
nent ceiling inside the frames. Tank
vessels have no ceiling, the liquid
cargo occupying all the spaces be-
tween the framing.

The Design and Construction of Po7vcr Work Boats

ONE OF THE FAMOUS "AKK MODEL" FISHING BOATS BUILT AND OPERATED
BY THE SOUTHWEST FISH COMPANY OF VERMILION, OHIO

CHAPTER XII

Constructing tne Deck House

OECK houses arc usually fitted
above the hull proper to pro-
vide living or operating ac-
commodations. They are usu-
ally of wood in wooden vessels and of
wood or of steel in steel vessels. The
structure is made as light as possible
without being too weak to withstand
the rough seas or to support other
houses, lifeboats, etc., which may be
above them. This light construction is
in order not to raise the vessel's center
of gravity by the presence of excessive
topside weights, for if made too heavy,
especially in small vessels with large
deck erections, the vessel would be
rendered unstable.

The house tops usually follow the
sheer line of the upper hull deck,
being sheered and cambered or
straight and flat as previously de-
scribed under "decks." The forward
end of deck houses are sometimes
perpendicular to the sheer line at that
point or else they are at an angle
half way between a vertical line and
one perpendicular to the sheer at the
point where their lower edge strikes
the deck (Fig. 76-a). The after ends
of deck houses are usually vertical.
For structuial simplicity, particularly
with straight sheers, the forward and
after deck house ends may be square
to the deck. Another reason for
this will be discussed under "doors
and windows."

Deck Houses Generally Rounded

In plan view the forward and after
deck house ends may be straight
across the deck and joined to the
house sides with a radius of from
nine to eighteen inches. This is
nearly always done at the after end,
but the forward end, particularly of
pilot houses is more often rounded.
In lower deck houses the rounded
forward end is laid in by taking a
radius equal to the forward width of the
deck house. An arc is drawn with
this radius, its center being on the
vessel's longitudinal center line. This
arc is then joined to the house sides
by one equal to one-quarter or one-
third of the forward house width.
Pilot house fronts may also be drawn
in this way or by a semi-circle whose
diameter is the width of the pilot

house. No gain is experienced by
rounded house ends particularly in
low speed vessels, and it is be-
coming customary to make the house
front straight with rounded corners.
This affords more room in the house
and simplifies construction.

Deck house sides may be parallel
to the upper hull deck side, at a dis-
tance in from the rail sufficient to
afilord a passageway beside the house.
This passage is from 18 inches to
24 inches wide in small boats and up
to five or six feet in large boats.
Sometimes the house side is straight
and parallel to the longitudinal cen-
ter line, but unless the vessel has
a long middle body, care must be
taken not to reduce the interior house
room too greatly. It may be pos-
sible to build the forward house
sides straight and parallel, tapering
the after sides to keep the outside
passage at nearly a constant width.

Height of Deck Houses

The usual height of deck houses,
measured from the top of the plank-
ing under foot to the top of the
planking overhead, is from seven to
eight feet. Sometimes in shallow
draft river vessels the height is more
than this, as much as 10 or 12 feet.
Pilot houses are usually higher than
other deck houses which may be
abaft them on the same deck. This
permits of placing transom windows
in the after end of the pilot house
above the top of the other deck
houses, so the helmsman can see
astern. Pilot house floors are raised
above the normal deck level to
enable the wheelman to see through
these windows and close down over
the bow.

Small boats may not have sufficient
depth of hold to permit the ma-
chinery to be entirely below the
upper hull deck. In this case head
room and ventilation are obtained by
building a low deck house or "trunk"
whose height is from two to four
feet above the upper hull deck.

The length and width of deck
house in a given boat is determined
by the accommodations it must en-
close as well as the external deck
arrangement which is influenced by

the service which the vessel is to
engage in. For example, although
a certain number of staterooms, gal-
ley, messroom, upper engine room
and toilet spaces could be placed in
one deck house on the upper deck,
there must be a passage outside
the house on each side of the ves-
sel, or a large hatch may be re-
quired on the forward deck. These
factors will limit the width and for-
ward ending of the house.

Then perhaps a mast with a heavy
boom and hoisting winch may be
needed forward, further affecting the
forward end of the house. If the
vessel is to tow astern, heavy towing
bitts must be placed on deck behind
the deck house. These bitts should
be located as far forward of the
stern as possible to permit of easy
steering while towing. This will
affect the after end of the deck
house.

Wooden Deck Houses

Figure 76-d is a cross sectional
elevation of a typical wooden deck
house side. The lower coaming or
"sill" is of heavy timber and is se-
curely bolted on top of the deck
planking, the bolts passing througla
the beams of the deck below. A
stopwater of flannel dipped in thick
white lead should fit between the sill
log and the deck planking to prevent
leakage under the house sides into
the cabin. In Fig. 76-t the house
is a trunk built over a deck open-
ing and the sill is bolted directly
to the carling which supports the
cut beam ends. Here the deck plank-
ing is fitted close beside the outer
edge of the sill and the seam thus
formed is calked in the same way as
for the other deck seams.

A frame work of vertical stanchions
is erected on the sill. These stan-
chions are from two to four inches
molded and usually four-inch sided,
having their lower ends notched into
the sill and their upper ends into
the "cap" or upper coaming timber.
The vertical stanchions are spaced
from two to three feet apart. At
the height of the window sills, it
is common to fit horizontal strut
timbers between stanchions and

The Design and Coiislnictioii of Poivcr Work Boats

'iherr.

^Deck Houie Side
Tlnrallel it ■iJteer cr
ii Ct»ttr Aiint-

/Trunk -

(cj

(h)

, Coomm4 r/ate

i^J

' , CoaminJ ^i^'*

ii/IL^

,CJ

Coanmt 'PJa'tt

Oeek-P^t4.

FIG. 7G— CONTOUR AND CONSTRUCTION OF WOODEN DECK HOUSES

sometimes diagonal brace logs are
built into the house framing.

The cap is above the tops of
window frames and may be under
the house top beams with filling
blocks between them, -or may be at
the ends of the beams. Various
wood house tops have been con-
sidered under "decks" in Chapter XI.

Long steel holding down bolts are
passed from the upper side of the
cap to the under side of the beams
or carlings on the deck below. These
rods are from l^-inch to ?4-'nch in
diameter with nuts over washers on
their upper and lower ends. The
rod spacing is from six to eight
feet and they should be located
close to a heavy stanchion so that
when tightened up they will not cause
a spring in the cap or carling.

How Sheathing is Fastened

Deck house sheathing is fastened
outside and also usually inside of the
framing. The material used in com-

mercial vessels is usually pine al-
though mahogany or other hard
woods are still employed in yachts,
especially for the inside sheathing.
Formerly the sheathing was panelled,
but it is now usually of tongue and
grooved planks.

The outside sheathing is from fl-
inch to ^-inch thick, the planks run
horizontally and the whole is usually
painted a light color. A half round
molding may be fitted at the level of
the window sills.

Inside sheathing is panelled in pass-
enger vessels but it is becoming more
usual to make it of V" chamfered
tongue and groove planks built in
vertically. The thickness of inside
sheathing is from ^-inch to §^-inch
and the finish is natural wood or
stained. A "wash board" or lower
molding plank from four to six
inches high and ^-inch thick ex-
tends around the inside of deck
house sheathing and partition bulk-
heads as in Fig. 76-d. A similar

upper molding, notched around the
beams is often fitted. Sometimes a
quarter round molding strip is sub-
stituted for this upper molding.

Care should be taken that the
seams of inner and outer sheathing
planks are parallel to the edges of
doors and windows. All sheathing
should be blind nailed to the stud-
dings and hammer marks should not
show.

The deck overhead in a deck house
is sometimes panelled but only in
saloons of passenger boats. Usually
it is sufficient to finish the under side
of the house top planking in a smooth
and neat manner. Deck beams are
sometimes boxed in with light sheath-
ing to make them appear massive.

Where considerations of draft
render it desirable to eliminate un-
necessary structural weight, the in-
side sheathing is omitted entirely or
is composed of composition wall
board. This compressed pulp ma-
terial is from tV-inch to A-inch thick
and should be treated so that it will
not absorb moisture. It is obtained
in sheets from three to five feet
wide and should be carefully fitted.
Molding strips of stained wood, 54-
inch thick by 2 to 4 inches wide
should fit over the joints and the
intermediate nailings. Wallboard

should be nailed at not more than
6-inch intervals along the edges and
intermediate rows of nails should be
not over 18 to 20 inches apart so that
buckling will not ensue.

Pilot Houses of Wood

Wooden deck houses are sometimes
fitted on steel vessels as in the case
of pilot houses or of light deck
houses in shallow draft steamers.
Pilot houses of wood are to minimize
the effect of surrounding steel on
the compass needle. All metal with-
in a radius of IS feet from the
compass should be non-magnetic to
render the error in reading less
marked. Even with this precaution a
steel vessel which pursues a fixed
course for a considerable period, or
which lies at a dock, will become
polarized by the earth's magnetic lines
of force, so that the vessel itself is
one large magnet which will act upon
the compass needle just as two mag-
nets affect each other. In order to
overcome this source of error in the
compass reading, compensating mag-
nets are fitted in the binnacle stand
which carries the compass and the
ship is "swung at her anchorage" or
turned around from time to time.
If the modern gyroscopic compasses
are used, these troubles are avoided.
Pilot houses are often made of steel
regardless of the above discussion,
for purposes of strength and be-

Constructing the Deck House

cause of the relatively slight in-
crease in error when the rest of the
ship is steel and when the com-
pass is properly constructed and at-
tended to.

Fig. 76-f shows the attachment of
a wooden pilot house to a steel
deck. Observe tlie deck plate to
which the house sill is bolted and
also the firring strips on the steel
deck beams to which the light deck-
ing inside of the house is nailed.

The lower deck house or "texas"
of a shallow draft river vessel is
sometimes attached to a vertical steel
coaming plate as in Fig. 76-g. Here
the coaming plate is riveted to a deck
plate by a coaming angle and the
sill timber is bolted on an inverted
angle bar several inches below the
top of the coaming plate. The outer
sheathing should cover the top of the
coaming plate and a molding strip
be fitted for sightlines as shown. The
extreme after end of the "texas" is
exposed to constant splashing from
the stern wheel and is therefore made
watertight. This can be done either
with two thicknesses of closely fitted
tongue and groove planking running
at right angles to each other, or by
making the bulkhead of light sheet
steel or galvanized corrugated steel.

Steel Houses for Tugs

Deckhouses of steel are sometimes
fitted on wooden vessels such as
tugs which navigate rough waters.
The lower attachment of such a
house to the wooden deck is shown
in Fig. 76-h where the steel lower
coaming plate is bolted sidewise
through a heavy sill log. The lower
coaming angle is riveted to the
coaming plate and secured to the
deck by bolts with countersunk heads
which pass vertically through the sill
log and deck beams below. A can-
vas stopwater dipped in thick white
or red lead is inserted between the
coaming angle and the sill log to
prevent leakage.

An alternative construction is given
in Fig. 76-k in which a steel deck
plate is fitted on the beams under the
deck planks. This plate is through
bolted to the deck beams and the
lower house coaming angle is riveted
to it and to the lower coaming plate

Steel houses in steel vessels (Fig.
77-a, b and c) have their side and end
bulkheads composed of:

1. A lower coaming piate which is
secured to the deck plating or to a
tie plate under the deck planking by
a lower coaming angle.

2. An upper coaming plate which
fastens to the house top with an up-
per coaming angle in one of the
ways already described.

3. House side plating which fits

between the upper and lower coam-
ing plates and is stiffened by vertical
angle bars bracketed at their tops
and sometimes at their bottoms.

The lower coaming plate is usu-
ally %-mQ.h to A-inch thick (weigh-
ing from 10.2 to 12.8 pounds per
square foot). Its height above the
deck beams is from 9 to 12 inches,
so that it need not be cut where
doors are fitted but the door sills
rest on its upper edge. The lower
coaming angle is of the same thick-
ness as the lower coaming plate. The
vertical flange of this angle is deep
enough to project above the deck
planking, being from 2}/^ to 3j4 inches
high and secured to the coaming
plate by a single row of rivets. The
deck flange of this lower coaming
angle is single riveted to the deck
or tie plating and is from 2^ to 3
inches wide. The tie plate is from
8 to 15 inches wide and weighs
from 7.6 to 10.2 pounds per square
foot.

The upper coaming plate is from
7.6 to 10.2 pounds per square foot
and from 6 to 9 inches high. The
upper coaming angle is of the same
thickness and has flanges from 25^2
iiiches by 2J^ inches to 3 inches by
3 inches, single riveted to the coam-
ing plate and the house top. The
tops of window and door frames fit
against the lower edge of the upper
coaming plate.

The intermediate house side plating
weighs from S.l to 7.6 pounds per
square foot (from J^-inch to A-inch
thick) and is cut out where win-
dows and doors are fitted. Some-
times this plating extends to the
house top and no upper coaming
plate is fitted. The exterior of the
house side plating may be flush with
butt straps fitted to the seams on the
inside (Fig. 77-c) or it may present
a paneled appearance by fitting these
butt straps on the outside of the
seams between the upper and lower
coaming plates (Fig. 77-a and b).

i^J

V---Xr.

Tint*.

— An<jlf

(i>

Um.'I.

xVer+cl
■Bo-tt 6trnf

(CJ

/ 1*

1 '■ 1

••

W
\ 1

" \
1

Lj .^_..

1 rn

ci.ofli'if''i^p'^''i"'

'•■ButtStra^

of C«) f*""^

of CIpJ) frtrr,
O^fiide of flooi*

i
(
I
I

l~anq;it)dina I l/lfo)
of Cc)fri>m

Out»io(e ef-Houif.

FIG. 77— CONSTIiUCTION DETAILS OF STEKL HOUSES

The Design and Construction of Power Work Boats

Doors are of the same material as
the bulkheads through which they
afford a passage, except that some-
times wooden doors are fitted in steei
bulkheads. Watertight doors are
usually of steel and are fitted to
watertight bulkheads. They are ar-
ranged to hinge and clamp shut with
dogs or to slide vertically or horizon-
tally.

Fig. 78-a is a hinged watertight
door on a steel bulkhead. The door
opening is 2 feet 2 inches wide by
5 feet 6 inches high and has rounded
corners to prevent weakness at these
points. A continuous forged frame
angle is riveted around the opening
or "arch" to make up for the
strength lost by cutting out the bulk-
head plating. This frame angle bears
against a rubber gasket on the door,
the gasket being secured to the door
plate by rabbeted steel strips fas-
tened with composition machine
screws. The door plate is stiffened
by an angle around the edge or the

plate may be "bumped" out as an
alternative. When closed the door
is held tight by "dogs" which clamp
over bronze wedges on the door
plate with handles on each side of the
bulkhead as shown. The bolt about
which the dogs pivot, passes through
a bronze bushing and has a nut on
one end to permit removal.

Vertical sliding watertight doors
are most frequently used in large
vessels and may be operated from the
deck above or from below. They
slide in cast steel guides riveted to
the bulkhead on each side of the
"arch" and have wedges on the door
which bear against sloped flanges on
the guide castings and force the
door against the bulkhead when
closed. The door may be raised and
lowered by means of a pinion and
rack or by a threaded spindle pass-
ing through a fixed nut on the door.
The rack shaft or the spindle are
turned by an endless chain on a sheave

KI(J. 7S~WATi:i! TICIIT DOOlt.S, All! POUTS AM) DEAD LIGHTS

or by electric motors. Sometimes a
releasing device is attached so that
the door may drop quickly in case
of accident.

The hinged watertight door is
most common in tugs and other
commercial power boats.

Interior Doors

Interior doors through joiner bulk-
heads are similar to those used in
building construction, being of wood
:iiid panelled. They are usually hcav
ier than doors of buildings and
should be carefully fitted. Some-
times horizontal sliding doors are
used where space is restricted, such
as in staterooms, but this type is
not satisfactory in practice since
difficulty in opening or closing arises
if the door leaves the guide runners.

Deck house doors of wood or
steel sometimes are in halves so
that the upper part may be opened
for ventilation. The upper and lower
halves bolt together and the lock
is on the lower half. A sliding bolt
holds the upper and lower halves
of such doors together. Pilot house
doors may have glass fitted in the
upper half, but if care is not taken
the glass will be broken frequently.
Wired plate glass offers a solution of
this difficulty.

Deck house doors have their upper
and lower edges parallel to the sheer
and their sides vertical. This cus-
tom renders doors very expensive un-
less the sheer is a straight line when
all doors are similar.

Occasionally it is necessary to fit
a bulkhead in passages for strength
only, in which case passage through
the bulkhead is afforded by an open
"arch" re-enforced by a bounding
angle and the door is omitted.

Openings in the sides of the hull

are called "ports" and are employed

for loading cargo or for furnishing

light and air to the living spaces.

Cargo ports are not fitted in wood-
en vessels and should be as small
as possible in steel ones, that the
hull strength may not be seriously
reduced. Coastwise vessels with "well"
decks have large swinging ports at the
sides of the wells. These are not com-
mon to power vessels and will not be
studied.

Small side ports often also serve
as doors to the upper between decks
in large vessels and are in halves
with a deadlight in the upper por-
tion. They are held watertight by
strongbacks or by dogs around tlie
edges and a gasket is fitted on the

Construcliiig the Deck House

rim which bears against the angle
framing arch. This type is sekloni
employed in power boat construction.

Construction of Air Ports

Air ports (Fig. 78-1)) consist of
a circular glass plate in a metal
frame which is hinged to a casting
riveted or bolted to the hull. The
glass is from .>^-inch to J^-inch
thick, depending upon the diameter.
The size of an airport is expressed
by the clear diameter of the glass
and ranges from 6 inches in small
boats to 18 inches in large vessels.

The rim in which the glass is fixed
is usually of polished brass or com-
position metal, although galvanized
cast steel is sometimes used. The
glass is secured to the rim by a
circular brass ring of quarter round
cross section which is held in place
by small machine screws. Cement is
usually introduced between the glass
and the rim to prevent leakage. Some-
times a cast metal cover or "dead-
light" is hinged over the glass rim
on the inside of the vessel. This
is usually hinged up and hooked to
the deck overhead. Its use is to
close the port hole in case the glass
becoiTies broken. A rubber gasket is
packed into a groove around the edge
of the deadlight cover and a similar
gasket is on the frame casting which
is riveted to the hull.

Circular ridges on the glass rim
bear on these gaskets when the port
is closed and when the cover is
down and prevent the entrance of
water into the vessel. Three hinged
eyebolts provided with butterfly nuts
are equally spaced around the edge
of the port and the cover and swing
into lugs on the rim of these. The
ports are held tight against the hull
by screwing down on the nuts. A
gasket is fitted between the airport
frame and the hull on the outside,
while a ring over this gasket fits
securely to the frame. The frame
casting passes from the inside of
the inner sheathing to the outside of
the hull planking or plating. Usually
a square wooden frame surrounds the
airports on the inside of the hull
and in large wooden vessels this
frame should be bevelled to afford
maximum light diffusion. This is
because of the excessive thickness of
the hull.

Air ports should be spaced midway
between the frames which should not
be cut in fitting the ports. Care
should be taken not to locate air
ports in the hull closer than two

and preferably three frame spaces
apart.

Stock air ports are carried by most
ship chandlers and can be selected from
their catalogs.

Fixed ports or "side lights" admit
light only to spaces in the hull which
are near the water line or are placed
in steel doors of deck houses. The
circular glass is in a watertight
frame of bronze which is riveted or
bolted to the hull and does not hinge
open.

Air ports and fixed ports near the
hawse pipes are protected by steel
bars or as will be studied under
"anchor handling."

Wire Glass for Windozvs

Windows of the drop or hinged
type are commonly fitted in deck
houses. Their advantage is in the
increased light and ventilation which
they afford, although they are more
liable to breakage in rough seas.

This danger was formerly reduced
by fitting wooden storm shutters out-
side of the windows. The shutters
could be taken down and stowed
away. Since the introduction of
"wired plate glass," shutters are not
needed if the panes are of this ma-
terial. The glass is poured with a
woven wire mesh in it, and acts
in the same way as re-enforced con-
crete. It will shatter under a direct
blow but does not fall out. Pilot
house doors should be fitted with wired
glass in all cases.

Drop windows when open, fit into
a pocket between the inner and outer
house sheathing. A recessed grip
in the top of the sash should pro-
ject above the sill so the window can
be raised. The sill may form a
hinged cover over the window pocket,
to present a pleasing appearance.
The pocket is lined with sheet cop-
per or galvanized sheet iron with a
drain to the outer deck. The sash

FIG. 79— CONSTIiCCTION OF ni.N(iKI) Wl.NllDWS ANU SKYI.KIIITS

The Design and Construction of Pozver Work Boats

C. WASHINGTON COLYER, HOCKAWAY BEACH EXCURSION BOAT
This craft powered with a 6-cyl., 7^ x 9" Automatic, carries 200 passengers and is operated by a captain

and two hands

slides in a groove in the sides of the
frame and the bottom pushes out
over a ridge. (Fig. 79-a). Pilot
house windows sometimes slide on
vertical brass rods (Fig. 79-b). Win-
dows with curved panes at house
corners are sometimes installed, but
should be avoided if possible because
of the cost of the special panes and
sash.

Hinged windows (Fig. 79-c) have
the upper part of the .=ash in two
sections hinged together. There is
a deep channel at the top of the
frame with clearance enough for vhe
sash to raise over the ridge on the
sill before hinging open. A hook
on the house beams keeps the win-
dow open. Hinged windows are
mostly fitted in the bunk cabins of
small vessels or in the after ena of
pilot houses which are raised above
the deck house enough to permit the
helmsman to see astern.

Skylights of wood (Fig. 79-d) or
steel (Fig. 79-e) usually hinge up

and may be opened or closed from
within by means of a lifting gear.
The covers are hinged at the center
and the frames must be watertight.

How Skylights Are I'ittcd

Wooden skylights have a wooden
coaming bolted to the carlings and
end beams of the skylight opening.
Engine room skylights should be
portable to permit removing machin-
ery for shop repairs or renewal.
The gabled skylight ends are con-
nected at the tops by a heavy rwlge
timber to which the hinges are
screwed. A drainage groove fits all
around the edge of the sashes to
prevent drip into the cabin below.
This groove drains to the deck at the
ends of ridge timber and at the
sides of the sashes. Unless the
light panes are of wire glass it is
necesary to fit a metal grid over
them for protection againt breakage
by falling objects. A canvas cover
or "tarpaulin" fits completely over

MANHATTAN WITH A DECK LOAD

Another Rocliaway Beach excursion boat with same power and capacity as Coli/er

the skylight and is lashed to the
coaming in heavy weather.

Steel skylights (Fig. 79-e) usually
have circular ports in the sash. The
steel coaming is riveted to a plate
top which is cut out in way of the
hinged sashes, the opening being sur-
rounded by an angle bar. The cages
of the sash are flanged downward
to minimize leakage and a rubber
strip or "gasket" extends around the
edges. Light metal strips screwed
to the sash secure the gasket. Stiff-
ening angles or tee bars re-enforce
the coaming and tops of the sky-
lights. The coaming is riveted to an
angle bar and is clipped to the ends
of deck beams v.'hich have been cut.
A margin plate surrounds the sky-
light opening and is riveted to ttie
beams and the coaming angle. In
small skylights through which it is
not necessary to remove machinery
or fittings, the deck beams extend
across the opening to maintain the
necessary strength of the deck.

Skylight lifting gear (Fig. 79-e)
may be of several diflFerent types but
a usual one consists of a vertical
shaft having a handwheei which can
be turned from within the cabin.
One or more bearings support this
shaft and its length varies according
to the point from which the sky-
light is desired to be opened. A
worm at the upper end of this ver-
tical shaft actuates a worm wheel
keyed to a horizontal shaft. The
worm and wormwheel may or may
not be enclosed in a casing (Fig. 79-e).

The horizontal shaft has one or
more levers keyed to it at one end
and pinned to the lower end of a
corresponding number of links as
shown. The upper ends of the links
are pinned to bearings on the sky-
light shutters so that rotation of the
levers by means of the worm, worm-
wheel and horizontal shaft, will raise
or lower the skylight shutters. The
wormwheel acts as a lock on the
worm for any amount of opening of
the skylight.

Some skylights have a slotted
quadrant bar pinned to the shutter
as in (Fig. 79-d). The slots in the
ciuadrant engage a pin on the sky-
light coaming and the shutter is
lifted from the deck above to the
renuired amount of opening.

Deck lights (Fig. 78-c and d) are
fitted over compartments where ordi-
nary airports, sidelights or skylights
cannot be provided. They may have
a cast bronze frame in which the
circular glass is cemented watertight
(Fig. 78-c), the frame being screwed
to the deck planks or plating. A
less desirable type has a thick prism
of rectangular glass with beveled
edges in thick white lead between
deck planks (Fig. 78-d).

CHAPTER XIII

Companions — Hatches — Rails — Awnings

GOMPANIONS are openings in
the deck which afford access
to the compartments below
or above it. They may be in
the sides of the deck-house or may con-
sist of a hut-like hood over a hatchway
having a ladder leading downward.

Fig. 80-a is a sliding companion
hatch of wood. It consists of a small
house built upon an opening in the
deck. A carling at each side joins
the deck beams at the ends of the
hatch and the intermediate beams
which were cut are notched into the
carlings. A coaming is bolted all
around the hatch to the deck beams
and carlings. The front of the com-
panion has double doors which vary
in height from 30 inches to 6 feet 6
inches. If these doors do not afford
full headroom, the top of the com-
panion slides back as shown to per-
mit entrance.

The sliding top may slope straight
back, traveling on girders as shown
or it may be rounded as in Fig. 80-b.
The minimum width of deck opening
should be 30 inches and the length
varies according to the slope of the
ladder so that the head of an aver-
age man would not strike the deck of
the opening in coming up.

Companion Slides

Deck houses and trunks of small
vessels where the height above the
coammg or sill is not sufficient to
permit the fitting of doors which are
of full headroom height (6 feet 6
inches above the deck), have a com-
panion slide or hinged hatch over the
low doors (Fig. 81-a and b). The
slide is the same, as for companion
hatches and has brass metal strips
fastened to wooden guide pieces with
countersunk screws (Fig. 81-b). The
door closes against the front of the
sliding top and is usually secured by
a hasp and padlock. If the hatch is
on a cambered deck and slides athwart-
ship, drain holes are cut in the
slide strips as shown. If the com-
panion top is hinged, the construction
is the same except that the slides are
omitted and hinges are fitted to the
cover at the side away from the door.
It is also desirable to install hinged
rods at the sides of the hinged cover

so that it may be opened to a degree
affording headroom without throwing
it completely back upon the deck.
Companions of this type are difficult
to screen properly and should be
avoided if possible.

Fig. 80-b is a full height steel com-
panion hatch with deadlights in the
sides. The coaming plate and con-
nections at the deck are the same as
for deck houses and a continuous
corner angle bar is riveted to the
sides, front and back. The steel

door closes against this angle at the
top and sides while a reversed angle
at the top of the coaming plate forms
a sill. The side and back plates to-
gether with the door are of from S.l
to 10.2 pound plating (% to % inch
thick) with single riveted "equal"
angle bars and stiffeners of the same
thickness.

Companion doors may be single,
double or divided. The latter two
types are as in Fig. 81-c and d.
They are resorted to where the pas-

/r'uneyerte •SecT/on.

Lon^rtiidinol

ff=

■ « ■ nv^pn

!::■:,---—

ib)

L "

FIG. 80— WOOD AND STEEL COMPANIONS

The Design and Construction of Pozver Work Boats

^ra/r: Aa/e

^Cem^nion ill tie y ■.

T"^^

lar^au/tfj^

Lej

3ech

iVooden Match.
(5mallj

■Coamma

C-'J

^^or//ro

Pack "Beam.

KIG. 81— np:TAIL CONSTliUCTlON OK

sage into which they swing open is
restricted. The hinges and locks
should be extra heavy and arrange-
ments should be made to hold the
doors open by brass hooks or by
spring catches. Rubber topped buf-
fers should be on all doors which
open against interior or exterior
joiner work having a fine finish.

The deck immediately in front of
companion doors is subjected to
severe wear so that treads of hard-
wood strips are fastened to the decks
at this point. Sometimes cast brass
or iron plates which are roughened
by a pattern or which have a cement
or lead filling in grooves, are used in
the deck in front of doors.

liow Hatches Arc Classified

Hatches may be roughly classed as
watertight, non-watertight, flush or
raised. Watertight hatches are fitted
over all compartments opening onto
decks exposed to the weather.

Wooden hatches are difficult to
keep tight. They consist of a coaiu-

COMP.UMO.N SLIDCS AND IIATCIIKS

ing bolted to the carlings and beams
around the deck opening. This coam-
ing has a rabbet on its upper edge
and the hatch cover fits securely into
i;. If the hatch is small the top may
be in one piece, usually rectangular,
composed of tongue and grooved
planks with a rabbeted frame and
short beams. Hooks on the coaming
engage eyes on the cover frame and
clamp the hatch closed. Sometimes
hinged hasps on the cover fit over
staples on the coaming, and pins
through the staple hold the cover
down. If the hatch is hinged, a pad-
lock on one staple may be used and
the hooks also be fitted at the sides.
(Fig. 81-e.)

Large wooden watertight hatches
have sectional covers on portable
beams resting in the notched and
rabbeted upper coaming timber. A
heavy canvas tarpaulin is stretched
tightly over the closed hatch by
means of an iron bar which is wedged
into metal lugs on the coaming. (Fig
81-f.)

Watertight steel hatches when small
are called "manholes" or "scuttles"
and may open into tank compart-
ments below decks as well as to the
weather. Manholes to tanks which
are seldom entered should be bolted
closed as in Fig. 82-a. The opening
should not be less than 11 inches wide
by IS inches long with circular ends.
A forged channel or double angle
ring encloses the opening, the cover
plate bolting on the upper flange as
shown. A gasket of hemp or canvas
fits between the cover and the coam-
ing ring. The tank, bulkhead or deck
plating which has been cut at the
luanhole, has a re-enforcing plate or
"doublcr" riveted all around the open-
ing to compensate for the lost
strength.

Manholes of Various Types

Manholes fitted with "strongbacks"
arc common to tank compartments.
The elliptical manhole plate is in two
thicknesses, the upper of which is
rarrov<er than the lower. The plates
are riveted together and a gasket is
fitted on the shoulder as shown in
Fig. 82-e. Two shoulder bolts are
riveted through the cover plate and
"strongback" bars fit over the screwed
er.ds of these bolts, extending across
ihc narrower dimension of the man-
hole. Nuts over washers tighten the
cover against a flanged manhole ring.

Hinged manholes fitted with "dogs"
are as shown in Fig. 82-c. They may
be square, round or elliptical and have
a number of forged lugs which engage
hinged bolts with wing nuts around
tlicir edges. The hinges have an oval
slot on the pin to permit of tighten-
ing the cover.

This type of fastening is employed
for steel watertight or oiltight
hatches with hinged covers. A plate
coaming from 9 to 48 inches high
surrounds the hatch opening and has
a coaming angle at the deck. If the
coaming height exceeds 20 inches it
is necessary to stiffen the plate with
brackets and angle clips. A rubber
gasket at the upper edge of the coam-
ing plate is clamped thereto by an
angle or by a flat iron bar. Cast or
forged steel lugs riveted to the coam-
ing, attach the hinges and the ring
bolts.

If the hatch is more than 24 inches
square, the cover plate should be
strengthened by an angle around the
edge. Hatches smaller than this
usually have a flat bar around the
edge of the cover for strength.
Hatches more than 48 inches square
should have stiffeners of angles or
bulb angles across the cover at inter-
vals of 24 inches.

Deck scuttles are of cast steel or
composition metal, not less than 18

Companions — Hatches — Rails — Aivnings

nor more than 24 inches in diameter.
They consist of a flush ring casting,
bolted or riveted to the deck planking
or plating and having a depressed
circular ridge on which a rubber
gasket in the cover bears. The cover
varies from ^ lo % inch in thick-
ness, is roughened on the upper sur-
face and has two hinged ring bolts
which lie flush in depressions and by
means of which the cover may be
lifted. The cover is tightened against
the ring casting on the deck by means
of six bolts with heads resembling
horizontal cams, or else by a central
bolt which screws into a bossing on
a hinged strongback under the scuttle.
A special wrench is provided to
tighten the scuttle fastening bolts.
When the cover is removed a cast
iron grating fits into the opening and
affords ventilation. This grating may
stow in three clips on a bulkhead
near the scuttle or may rest in de-
pressed lugs under the cover when
the scuttle is closed.

Steel cargo hatches usually have
wooden covers which rest on portable
beams in the hatch opening. A
tarpaulin is stretched over the top of
the hatch in the manner described for
wooden hatches.

Ladders and stairways may be of
metal or of wood and are vertical or
inclined. Inclined ladders should not
extend athwartships in vessels for
rough water service, unless this ar-
rangement cannot be avoided. This
is because of the danger of falling
down them when the vessel is rolling.
In passengers' living spaces stairways
are usually built with a slope of 45
degrees and with good wide treads
and ornamental railings. These some-
times turn from two athwartship sec-
tions to a "grand stairway" opening
in the saloon. Curved stairways are
not recommended for use on vessels,
it being better to change the direc-
tion of the stairs by introducing a
landing.

All ladders are composed of two
side pieces which are parallel and
fastened at the top and bottom ends
to the decks. Horizontal rungs or
"risers" are fitted between the treads
pieces and spaced about 9 inches
apart in vertical direction. Sometimes
"risers" are fitted between the treads
to close the openings between them.
Sloping ladders have hand rails of
ornamental wood or of plain iron or
brass pipe.

Fig. 83-a is a typical wooden slop-
ing ladder of ash or oak. Angle iron
clips are bolted to the sides and to
the deck below as well as to the
hatch coaming at the top of the
ladder. A sheet brass covering is
tacked over the door sill at the top
of the ladder and the treads have a

lb)
Watertight
Jl^ack £cuft/e-

^as/eat

(C)

Hin^e<J Wtifert/ffht
/"Janhok-

KIU. 82— WATERTIGHT HATCHES AND MANHOLES

protective covering of rubber, linoleum
or of brass castings with lead or
cement filling in grooves thereon.
The front edges of the treads have
sheet brass strips to reduce the wear.
If risers are installed they are pro-
tected by polished sheet brass "kick
plates" neatly tacked on. The hand
rail is fitted to cast or forged sockets
on the outside of the side pieces.
The treads should be at least 6 inches
wide.

Engine Room Ladders
Steel ladders may be similar in con-
struction and are generally fitted in
the engine rooms. The side strips are
from 14 to f^ inch thick and at least
4 inches wide. The treads are cast
iron with ribbed or roughened top
and bolted to the sides by angle iron
clips. "Subway" or similar gratings
form an excellent tread for such lad-
ders. No risers are fitted and the
rails are always of metal.

Vertical wooden ladders have the
same construction as that in Fig. 83-a

except that the risers are omitted.
Sometimes a strip of canvas is lashed
under open ladders to close the open-
ings between treads, particularly in
side ladders which lead from the deck
to the water. Such ladders are sup-
ported by forged arms from sockets
on the side of the vessel and have
wooden gratings at the top and bot-
tom. They are arranged to hoist up
by a block and tackle on a small
davit and to be removed and stowed
in the hold during the voyage. In-
stead of a pipe rail a rope is led
through forged stanchions around the
gratings and down the sides of the
ladder.

Vertical steel ladders to holds and
compartments entered only at inter-
vals, are composed of two flat bar
strips with round or square bars for
rungs. These rungs are riveted into
the side bars. Sometimes the rungs
are forged to a U shape with flattened
ends which rivet to the bulkhead
plating. Such rungs are at least 3

The Design and Construction of Poiver Work Boats

iktiterCoifBrtii

Lmolfum. ruhhtr, or caSf irva ^//M

y <fnb Ftf//

(4J

,l'/e"P,fre

yi'Pipt

'f^'

Ccj

C/dPi

r/^et

Frame

^^E-

("J

[A.

(AJ

FIC. 83— COXSTKUCTION DRTAILS OP LADDKHS A.ND HAILS

inches clear of the bulkhead. Again
the bar rungs may rivet through two
of the vertical bars which stiffen the
bulkhead and also serve as sides for
the ladder.

On a non-watertight steel bulkhead
forming a chain locker partition or a
swash bulkhead in a deep tank, semi-
circular holes may be cut 12 inches
apart horizontally and 9 inches ver-
tically to form a ladder. These holes
should be at least 4 inches wide to
fit the foot of an average man.

Ladders are fitted on masts and in
ventilators or trunks between decks
to form emergency exits. Where a
ladder without side rails or a vertical
ladder has an open passage or a
bulkhead at the top, grab rails should
be fitted above the ladder (Fig. 83-b),
or the rail should extend above the
top of the ladder so that a person
may stand erect when coming up or
going down.

It is often necessary to hinge lad-
ders at their tops in order to lift them

out of the way. Means should be
provided for hooking the lower ends
of such ladders to the deck above
when hinged up. The width of lad-
ders constantly used should not be
less than 27 and preferably 30 inches.
Ladders occasionally used may be as
narrow as 10 or 12 inches.

Rope ladders with wooden rungs
are called "Jacobs ladders" and are
used for getting into small boats be-
side the vessels.

Rails and Their Construction

Rails should be fitted around the
edges of all decks, around all open-
ings in the deck except at the point
of access, at the margins of all cabin
tops or house tops which are fre-
quented by persons. Grab rods are
fitted at the sides of trunk cabins,
around the front of pilot houses, in
passageways and at tops of ladders.

Open rails may be of metal or
wood (Fig. 83-c to f). Closed rails
or bulwarks of metal or wood are

sliown in Fig. 83-g to 1. Fig. 83-c is
a rail of standard pipe (galvanized).
It consists of 1^-inch stanchions
spaced from 3 feet 6 inches t6 4 feet
apart having standard flanges screwed
to their lower ends. These flanges
are screwed or bolted to the deck
planks or plating. If such rails are
fastened to the upper edge of a sheer
strakc, it is necessary to weld the
lower end of the pipe to a forged
palm as in Fig. 83-d. The pipe rails
arc from 2 feet 6 inches to 3 feet
6 inches above the deck, and there
may be two or three of them. The
top rail is usually from 1 to 1^-inch
pipe screwed to the stanchions by a
standard "T." Where the rail turns
at right angles a sight outlet "L" or
"T" may be fitted.

The intermediate rails may be the
same size as the top rail and the
stanchions, but are usually from J4
to 1 inch in diameter. Their connec-
tions to the stanchions are by crosses.
Side outlet "T's" are fitted at turns.

Forged or cast rail stanchions may
replace those of ordinary pipe (Fig.
83-d), the sizes and connections being
as shown. The rails in this case
should also be of standard galvanized
pipe. Sometimes the pipe rails are
replaced by a single wire rope or "life
line" passed through the forged
stanchions. Occasionally in passenger
vessels the upper rail is of wood on
metal stanchions as shown.

Metal grab rails (Fig. 83-m) have
small forged or cast stanchions
screwed or bolted to the sides or top
of deck houses. Wooden grab rails
are shown in Fig. 83-o and p.

Wooden rails (Fig. 83-e and f)
have plain or ornamental stanchions
supporting a top rail and having
metal clips screwed to the deck. The
sides are of light planks or rope
netting.

"Bulwarks" or rails solidly enclosed
except for deck drainage openings,
are fitted on tugs and the lower decks
of cargo and passenger vessels. They
tend to prevent waves from washing
over the deck but are not desirable if
heavy seas are encountered, since they
trap the water and make it difficult
for the vessel to free itself of seas
which have been shipped.

Metal bulwarks have plating from
10.2 to 25 pounds (Fig. 83-g, h and
k) which is riveted to the upper edge
of the sheer strake. A rail of channel
or bulb angle is riveted at the top of
the bulwark plating and stanchions of
forged round or structural steel sup-
port both the bulwark and rail as
shown. Wooden bulwark rails are
fitted on passenger vessels and tugs.
In the former case the rail is of 2 x
4-inch or 3 x 6-inch hardwood, bolted
to an angle (Fig. 83-k), the bolt heads

Companions — Hatches — Rails — Awnings

being countersunk and the holes
pkigged with wood. Tug rails arc of
oak 4 X 8-inch to 4 x 16-inch.

The height of bulwarks in tugs is
18 to 24 inches above the deck. In
passenger vessels the height corre-
sponds to that of open rails.

Wooden bulwarks (Fig. 83-1 and
n) have stanchions formed by ex-
tending the upper ends of frames
through the deck. The rails are of
the same height as those on steel
bulwarks. Small power tugs have
low rails of a single log, tapered as
shown and with a rail on top.
"Scuppers" or drainage ports are cut
at intervals in wooden bulwarks.

Azvring Stanchions and Fittings

Awnings of canvas are fitted over
open deck spaces for shelter from the
sun. They may be stretched over a
pipe frame and lashed at the edges;
or, in larger vessels, may have a
wooden ride bar and spreaders (Fig.
84-a). The canvas is white or khaki
colored and of No. 4 or No. 6 weight.
Small boats have awnings rolling over
a rounded pipe frame or of the "auto-
mobile" top type which folds down.

Vessels operating in warm climates
may have double awnings with an air
space between and the edges of the
canvas may overhang the ship's sides.

It is conventional to install a canvas
"eyebrow" over the windows at the
front of pilot houses (Fig. 84-b).
This is painted green underneath but
does not afford real protection from
the glare of the sun which is re-
flected upward from the water to the
eyes of the helmsman. The eyebrow
serves to keep rain oflf the pilot house
windows to an extent but is not really
needed.

Canvas "weather clothes" lashed to
the rails at the front and sides of the
bridge protect the occupants from the
wind. They sometimes extend to the

FIG. 84— AVVNI.NG STANCHIONS AND FITTINGS

level of the eye (about 4 feet 9 inches
above the deck).
Awnings and weather clothes should

always be fitted on the bridge, even
though not installed elsewhere on
the vessel.

The Design and Construction of Power Work Boats

o c

CHAPTER XIV

Masts — Davits — Wmclies — Wmcllasses

XN MOST commercial power
boats the sole use of masts
and rigging is for cargo hoist-
ing and for signaling either
liy flags or by radio telegraphy, com-
monly known as "wireless." Vessels
rigged to carry sails and fitted with
engines for propelling them in calms
or to assist the sails in a light breeze,
are not properly "power boats" and will
not be considered in detail here. The
rigging is complicated and caries con-
siderably according to the method of
fitting the sails. In general the sails
are carried by from one tO' four masts
in vessels which are "square rigged"
and from one to seven masts on "fore
and aft" or "schooner" rigged ves-
sels.

The maats are named up to four
and beginning at the forward one as
"fore," "majn," "mjzzen" and "jig-
ger" or "jury." So, if there are two
masts, the forward one is the "fore-
mast" and the after one the "main-
mast." If there are three masts, the
forward one is the "foremast," the
center one or second one the "main-
mast," and the third or after one is
the "mizzenmast." The fourth mast
or "jigger" is not common in square
rigged ships and has its sails fore
and aft as a rule.

Masts and Rigging

Masts are a single pole or in two
lengths on modern vessels. If in
two lengths, the lower piece is the
lower ma'st and the upper section is
the top mast. The point at which the
topmaist is fastened to the mainmast
is also that at which the strong
athwantship guys or "shrouds" sup-
port the mast. This point in all
maists is the "hounds." It is also
n-ecessary to fit longitudinal guys
called "stays" to the masts. These
are "backstays" if cm the after side
of the mast, "forestays" if on the
forward side and "springstays" if
horizontal or nearly so between two
masts. The stays and shnouds are
fixed and have no blocks or tackle
on them except means for tightening
or I'oosen'ing; they are termed "stand-
ing rigging." Ropes used for hoist-
ing and lowering sails, spars or cargo

booms are fitted with block and tackle
and known as "running rigging."

Since the wind pressure against the
sails tends to bend the masts for-
ward, they are inclined backward
so the backstays will have a greater
spread and the mast be subject to
less strain. This backward imclina-
tion is from -J^-inch to ^-inch per

foot oif height in common practice
and is called a "rake." Pole masts
in vessels without sails need not be
raked except to conform with cus-
tom which has affected judgment of
appearances.

Most sailing vessels have a bow-
sprit at the stem to afford great
spread of the forestays and permit

Fia. 85— IlOW POLE MAST AND BOOM IS KITTKU

7 iic Design and Constrnctiou nf Po7ver Work Boats

(CO

(b)

O O

D£7fi/l />7/liT F'^/^^£'?'S

/^/<yr rt:>aA'£>/?7/o/rc>-

'V/iir /^ac/y/^/ir/iO^

-3ooiv
\ Crafc/?-

KUi. 8G— CONSTnUCTlON ANO INSTALLATION OK STKKL MASTS. ALSO BOOM CItOTtll

carrying jilisails of larger area. Sonie-
'times the bowspri-t has an extensioin
spar or jib boom at its outer end.

The "rig" of a vessel is named
from the cut and position of its sails.
Where these are rectangular and hung
from a spar at their upper edge, the
spar being fastened at its middle to
the mast, the vessel is called' "square
rigged." When Ihe forward verti-
cal edge of the sail is attached to
the mast, the vessel is "fore and aft
rigged" or "schooner rigged."

Pole maisits as fitted to commercial
power boats are similar in arrange-
ment to !""ig. 85 and are usually ot
wood in vessels up to ISO feet long,
that is where the pole is of such
height as to be obtained in a single
length of the proper maximum diame-
ter to withstand the stress due to the
load'S. The cross section is circular

and is greatest at the point where the
mast passes through the upper deck.
Here strong wedgmg called the "part-
ners" is fitted, the mast tapering up-
ward to the hounds and downward to
the foundation or "step." The re-
dixtion in area at the hounds is
about 18 per cent of that at the part-
ners.

Steel mas'ts are not usuailly fitted in
power boats, being confined to I'arge
seagoing vessels. The mast may be
a solid steel tube, a built-up tube
stiffened inside with angle bars, a
structural or built-up "H" section, or
a latticed girder. (Fig. 86-a, b, c, d).

The lower end attach^ment of masts
is known as the foundation or "step."
It is usually fitted on the center keel-
son as in Fig. (86-h-i and k), although
sometimes where the hold is deep the
masts extend to one of the lower

decks or the top of a shaft tumiel.
In this case it is necessary to fit
heavy stanchions under the deck sup-
porting the mast or to .introduce a
transverse bulkhead. The foundations
must be braced athwartship by heavy
knees in single bottomed vessels,
but steel vessels with double bottoms
require .merely a heavy doubling plate
on the tank top at this point.

Wooden masts should be mortised
into the foundation timbers. Steel
ma'sts are riveted to the foundation
girders .by angles as shown.

At the point where masts pierce the
upper or main strength deck they
must be rigidJy secured against de-
flection by a structure call'ed the
"partners." This conisists ol deck)
beams forward and aft of the mast
with connecting longitudinail carlings
clo'se to the deck o.penin.g. There
should be but one set of "partners,"
the spar being free to deflect be-
tween t.his poiint, the hounds and the
foundation. The decking is locally
stren.gthened by miargin .planks in
wooden vessels or .by doubling plates
with an angle rinig or clips im steel
vessels (Fig. 86-e-f and g).

Partners on weather decks must be
made watertight at the wedges by
fittin.g a canvas or metal hoo.d'. Struc-
tural masts have stapled partner an-
gles without wedgiing and calked
watertiight. If the mast passes
through a deck house top which
is of light construction, the partners
are on the next lower strength deck
and a flexible canvas hood is tacked
wiatertight air.ound the opening where
the mast pierces the .light super-
structure .deck.

Cargo Booms for W orkboats

The power workboats it is customary
to fit cargo booms on. the mast .thus
facilitating the loadin.g of heavy car-
go. The bo'om is pivoted at its lower
end to a point on the mast just above
the partners as in Fig. 85. This
.point is pivoted in two directions
so the outer end O'f the boom can be
either elevated' ("topped") or swung
ho.rizon tally in transferrin.g the car-
go fpom the wharf to the vessel's
• deck. Two forged rings (a) are
fitted tightly to 'the mast and a strong
vertical pin (b) with an eye and
shoulder at its Uip.per end is .passed
through vertical bearings on the for-
ward side of the mast rings. A nut
or split pin is at the lower end of
tlie large vertical pin. to prevent it
from jumpiu'g out. A pronged forging
is tightly fitted to the low^er end
of the boom and engages the eye in
the pin on the mast by means of a
strong horizontal bolt or pin (c).
The upper mast ring has an addition-

Masts— Davits — Winches — Windlasses

al eye (d) for atfachiiiig' the guide pul-
ley (e).

The ib'O-om \s usually of wood al-
thoaig'hi it may be a steel eyebeam or
a latticed steel 'g-irder. At the free
enid of the boom is a forged ring
(f) with usually four eyelets. The
I'ower of these eyes (g) receives the
lifting tackle (usually inultiple effect).
The uipp«r eye (h) secures the lower
block ol tihe "toppinig lift" tackle
which naises or lowers the boom.
Swinging the 'boom from ship to dock
is done by the "varags" which -attach
to the eyelets on eaoh side of the
end ring. The vamg on the side
toward the dock is of fixed length so
the iboom -with its load is free to
swiii'g toward the wharf but cannot
swing lOUitward' beyonid the hatch
opening. When the vessel is under
way the boo'm is lowered to a hori-
zontal position and supported at its
outer end by a "boom crutch" (Fig.
86-mi). This is a portable structure of
forged bars or structural shapes with
a semicincular depression, at the top
into whi'ch the boom fits and is held
by a cover piece hinged or bolted
over. The lower ends of the crutch
bolt to flush castings or angle clips
on deck.

Davits

Davits are really small cranes and
are employed for hoisting or lower-
ing anchors, Mfeboats or companion
ladders. Occasionally where light
cargo is -handled a davit with block
and falls is installed on deck at each
side of the hatch instead of the cus-
tomary mast and boom. Fig 87 (a)
show:S a typical' davit made of a
forgied round bar. The head is shaped
at the sides as two eyes for attacb-
mient of guys and stays while a hole
is drilled vertically to take the eye
b'olt 'from which the lifting gear is
hung. A cleat is welded to the davit
below the curve of the overhung
arm for securing the hoisting line.
Sometimes this cleat is served to the
davit with wire. A support bearing
is situated on the vertical shank just
below the curve of outreach. This
bearing -should be metalline or bronze
bushed as -shown and is usually an
independent forging o-r casting se-
curely bolted to the deck house,
cabin trunk or -bulwark rail, de-pend-
in-g upon the locationi and utility of
the davit.

If the davit passes througb a deck
at the support bearing, a canvas
hood is fitted above this bearing
to prevent leakage. The lower end
of the davit is rounded and rests on
a hardened steel butto-n in a step
bearing -casting. Some vessels with
open bulwarks have the davits at the
rail, making it necessary to fit a

Brtvjf JUL,

(3J

, SuaA/na — ,

.y^

^■

FIG. 87— DAVITS AND HOW THEY ARE INSTALLED

single casting which acts as a coin.-
bined support and step bearing. (Fig.
87-ib).

Boat side l-adder an-di car-go- davits
are as in Fig. 87 (a and b). Fig.
S7-C is -an anchor davit.

Large vessels w-ith heavy bo-ats
sometimes have rotary davits of struc-
tural I-beams bent to shape. Special
davits of the pivoted, link or quadrant
types (Fig. 87-d to f) are also used
in large vessels but will not be de-
scribed in detail since they are too
bulky and expensive for use in most
smaller vessels.

Life boats should be carried by all
power boats and should accommvo-
date the maxim-um number of per-
sons which the vessel is apt to carry.

The lifeboats for large vessels are
usually of the double ended "whale-
boat" type of w-ood or steel. They

have a rated carrying capacity of one
person -for each 10 cubic feet of hull
volume -and- have air-tight compart-
ments at the ends and under the
thwarts to afford safety against
sinkage. The cockpit floor is above
the water level and is water tight.
Check o-r flap valves which -open out-
ward are in drain pipes from the
cockpit, so that water shipped over
the side will quickly run off and
lighten the boat. Oars with rowlocks
for pulling and steering purposes are
in the boat, als-o a "breaker" or sni-all
cask of water and a tin of sea bis-
cuit. A light lime with cork buoys
is fitted through eyes all around the
gun-wale and a portable rudder with
tiller is provided.

The entire lifeboat is sto-wcd on
wooden or light metal "boat chocks"
or cradles and a davit is at each

The Design and Construction of Poxvcr Work Boats

end of the boat. The lifting tackle
is shackled) to patent quick-releasing
hooks at each end of the boat. These
hooks will collapse and release the
tackle when the boat is water borne
or when a tripping device is operated
by one of the o'ccupants. The outer
boat chock is collapsible or hinges
down so the boat will swing outboard
with a minimum of hoisting and its at-
tendant delay.

Ordinarily the boat is secured: in
the chocks by laslhings fronn a 'carovas
cover which stretches over a ridge
bar and is fastened all around the
gunwale. In tinies of danger when
the boat may be needed quickly, it is
Ewun.g out over the vessel's side and
lashed to a spar fitted with heavy
pads, which spreads between the
davits. This spar is known as a
"pudding boom."

A solid rrt'C'tal rod with shackles
and turnbuckles, spans from the head
of one davit to^ the other when the
boat is stowed inboard. Wire rope
guys with turnbuckles and thimbles
are secured to the outside of each
davit head and to pad eyes on the
deck. The davits are thus held in
posiition when not in use.

Lifeboats are carried on the house
tops Oir trunk top in most power
boats. When, the distance between
the rail and the deck house is great,
causing an excessive outreach of the
davit arm by the usual method of
boat stowage, skid beams are fitted
over the passage at the house side
and the boats stowed on a slatted
platform over these beams. By this
arranigement the davits can be at the
vessel's siide and the boats dropped
clear of the rail.

//IJ £LEYAT/OfY

III! I

(£-^ .SSackle

Chair)'

(r)

6f-ui^ Lmk Chair?

((S) Pel/cart h'ook.

0J EfevATiOff

-2)rum H«ae^

jTo^fan Bar
'' SocksTs

■ tVAt/jbs
^Drcim

P4ia//^iH

yarr^ea/ ^Jiifi:

■^auiit
T'l/be

^haifiuJai

FIO. 88— WINCHES, WINDLASSES AND GROUND TACKLE

Tvarge vessels should always have
at least one lifeboat fitted with a
gasoline engine. It may not -be pos-
sible to accommodate all the passen-
gers in boats but liferafts are then
stacked on the deck house to make
up tbe s'hortage. These rafts may
be of pontoons w.ith slatted wooden
pliatforms on top and underneath,
with buoyed life lines, oars and row-
locks. Modern types resemble large
elliptical ring buoys and have rope
nets ill the center.

Small power vessels use their life-
boats for dinghies and such boats are
either flat bottomed or dories. They
are lashed bottom up on the cabin trunk
and have lig'ht davits, or if light
enough, are lifted over the side by
hand.

In general, precaution s'hould be
taken that wooden lifeboats are put
into the water frequently so that
the seams will not leak due to drying
out of the planking. Metal lifeboats
shoaild be kept well painted. Tackle
and releasing gear 'sihould be fre-
quently overhauled and kept free from
paint. The crews of all boats should
1)6 schooled in rapidly manning,
launiching and rowing the boats.

Winches for Hoisting Cargo

Winches are machines for hoisting
cargo and are fitted at the base of
masts or derrick posts close to
hatc'hes. They may be hand, steam
or electric driveni and oonsist of on€
or more dmums attached through
mechanical gearing.

Fig. 88-a is a hand powered winch
for small boats. The power is ap-
plied by turning crank (a) which
is keyed to shaft (b) and also car-
ries the pinion (c). The spur gear
(d) is keyed to the countershaft (e)
which also 'Carries the pinion (f).
The Shaft (h) has ispur wheel (g)
driven by the pinion (f) and carries
the druim (i) on -which the hoisting
rope is wound. The entire mech-
anism is supported by bearings in the
pedestal castings (k) which are bolt-
ed to the deck through a bed plate.
Gypsy heads may be fitted on each
end of the drum shaft (h) and are
used for swinging the boom. If the
winch is to be used for topping the
boom an additional drum is necessary
to take the lead from the topping
lift. If the winch is of higher power,
driven by gasoline, steam or electrici-
ty, the principle is similar to this
but the crank (a) is replaced by the
crank pins of two horizontal steam
cylinders, or a worm shaft driven
by an electric motor or gasoline engine.
.\ countershaft with clutch may drive

Masts — Davits — Winches — Windlasses

the winth from the main propelling
engine. The winch is conti-olled by
throttles or controller for regulating
the applied power and has brakes
for holding the drums. A clutch is
fitted to the shafts of all drums if
more than one is on the winch.

Capstans (Fig. 88-'b) are used for
handling towlines at the towing titts
or on the forecastle and- for warping
the vessel. They consist of a drum
with whelps driven through a ver-
tical shaft by an engiine or motor
usually below decks. They may be hand
operated by inserting long wooden cap-
stan bars into the sockets shown and
having the crew push these bars when
walking around the barrel. Small elec-
tric capstans with motor inside the drum
may be obtained and work very sat-
isfactorily.

Windlasses are used solely for
anchor liandling and warping the
vessel. They are hand operated and
fitted in co'mibination with mooring
bitts on small vessels. Windlasses
with independent motor or engine
are used on large vessels. The loca-
tion is near the bow close to the
hawse pipes.

A typical windlass has a 'horizontal
shaft sup'ported by bearings in ped-
estal castings. Gypsy heads are us-
uaMy keyed to the outer ends of this
shaft and revolve with it. One or
two "wildcats" are on the horizontal
shaft inside of the pedestal bearings
and a screw operated cone clutch
thrown in or out by a wheel causes
the wildcats to revolve with the hori-
zontal shaft or to remain stationary
w'bile the shaft turns. A brake on
each wildcat holds it fast if desired.
The main shaft is driven through
a worm and worm wheel by a motor

or engine which may be close to the
windlass on the same deck or, in
large vessels, on the deck below.

Fig. 88 (c) and (d) is a diagram
showing a typical windlass in rela-
tion to the mooring or anchor gear.
The anchor cliain is stared in a conv
partment called the "chain locker" at
the forward end of the vessel. The
inner end of the dhain is securely
.shackled to a ring or pad eye on
the bottom of the chain locker. If
there are two anchors it is neces-
sary to fit a central bulkhead in the
chain locker so the two chains will
not become tangled. The chain leads
up throiugfli a chain pipe which pierces
the deck and has a removable wood-
en or sheet steel cover fitting snugly
around the chain to keep water out
of the chain locker in wet weather.

The chain then passes around the
wildcat, which is merely a large
chain sheave with jaws fitting the
links. The wildcat 'may be on a
horizontal shaft as shown or it may be
on a vertical shaft under a capstan.
From the wildcat the chain passes to
the upper end of the chain pipe in
large vessels, or thro-ugh a chock
on deck at each side of the bow
in small vessels. A chain stopper
is installed between the wiildcat and
hawse pipe on large vessels, to pre-
vent the chain frorn running out too
rapidly. The chain is attached to a
shackle on the upper end of the an-
chor shank.

Anchor chain consists of links, the
size of chain being designated by
the diameter of the bar of which
the link is composed. Figs. 88-(e) and
(f) show "open link" and "stud
link" chain, the two types univer-
sally used. A shackle with its pin
connection to the anchor is shown

by (Fig. 88-e). Sometimes provision
is made for letting go the anchor
chain in an emergency by a "pelican
hook" (Fig. 88-g).

Hawse pipes are of cast iron or
steel and consist O'f a deck ring cast-
ing to which is rabbeted- the pipe
itself. The deck ring vs extra heavy
on the after side to- allow for wear
by rubbing from the anchor chain.
Doubling plates and closely spaced
beams with carlings form a founda-
tion under the deck ring casting. The
li-olding down bolts are countersunk
on the upper ends with gjro-m.mets
and washers under the nuts.

The lower end of the chain pipe
is bolted or riveted to the hull by
an elliptical flange with rolled face
and the frames are extra strong at
this point. Usually one or more of
the transverse frames are out to pass
the hawse pipe, in which case short
local stringers join the cut frame
ends -to the adjacent intact frames.
A doubling plate is fitted under the
shell flange of the hawse pipe, to
strengthen the hull and provide
against wearing away when hoisting
or lowering the anchor. All airports
near the anchor should have heavy
bars outside to protect the glass from
breakage.

Hawse pipes are not usually fitted
on vessels less than 125 feet long, in
which case the anchor chain passes
throuiglh a mooring chock (Fig. 89-f),
I>assing th.rougih the bulwark or fore-
castle side. If there is no bulwark,
an open chock usually with a -roller on
a bronze pin (Fig. 89-g) is used to
hold the anchor chain in position.
In small vessels the anchor is at-
tached to a wire rope or manila
hawser instead of to chain.

Photo copyright by Edw.
CAJIOUFLAOKD 110-FOOT IIMTI-n ST.XTKS SUBM.VKINE CHASEIt
Over 400 of these boaLs ucre built since June, 1017, mostly by yacht and tioat Ijuildeis in the United States — They penetrated every iiart of tlie war zone, and

made a wonderful record for sea^-orthiness and reliability

The Design and Construction of Power Work Boats

"IIAAKU.X"
A southern Alaska canning; company's herring seiner and cannery tender

CHAPTER XV

Anchors — Bitts — Towing — Deck Drainage

'NCHORS are varied in type
(Fig. 89-c-d-e) and are of
cast or forged steel. Stocked
anchors (Fig. 89-e) were orig-
inally the prevalent design. They con-
sist of a metal shank with two curved
metal arms terminating in strong trian-
gular flukes. The upper end of the shank
has the usual shackle for attaching the
anchor chain and just below this is a
stock of wood or bar iron, turned at
right angles to the plane of the arms.
This type of anchor is still considerably
employed in vessels without hawse
pipes.

An anchor davit must be used to
lift this anchor on deck by means of
a block and falls which is hooked
to the "catting shackle," located at
the anchor's center of gravity on the
shank. The anchor is lashed secure-
ly to wooden chocks on deck when
not in use. Sometimes a "billboard"'
or sloping platform is built on each
side of the deck close to the bow.
The stocked anchor is then lashed in
place on the billboard and arranged to
launch itself wlien a tripping device
is released by pulling a lanyard.
With this arrangement the anchor
chain may lead from the anchor
down over the vessel's side to a
hawse pipe, through
which the chain re-
turns up to the
windlass on deck.
This, however, is
much less con-
venient than using
stockless anc h o r s
as below described.
Whenever a hawse
pipe is fitted, and
sometimes even in
small vessels with-
out this pipe, a
stockless anchor
(Fig. 89-A-C) is
used. This is the
mo.st prevalent of
anchors at this
writing. It consists
of a forged shank
with chain shackle
at upper end, cat-
ting shackle at
point of balance
and a pin at the
lower end. The

flukes are shaped as shown with a
swelled body connecting them and
hinged about the pin. The flukes can
open to 45 degrees on each side of the
shank but are prevented from swinging
beyond this by stop lugs on the fluke
body. Stockless anchors are housed in
the hawse pipe when not in use (Fig.
89- A).

Mushroom anchors (Fig. 89-D) are
mostly used on small vessels and light-
ships. While their holding powers are
perhaps the most certain it is difficult to
stow them in the larger sizes because of
their bulk. Lightships have the hawse
pipe through the stem at or near the
water line and the anchor can conse-
quently be housed securely without
fouling the ship's side. A hole cut in
the dished blade serves to take the
hook on the catting tackle.

The size of all anchors is specified
by stating their weight in pounds.

Bitts for Towing and Mooring

Bitts or "bollards" (Fig. 90-A to D)
are mainly used for towing or for
mooring large vessels. Towing bitts
are usually of cast steel (Fig. 90-A)
with two posts on opposite sides of
the vessel's center line. Strong bolts
through the base secure the bitt to a

TUG FOR GOVERNMENT WORK
A type of boat in which towmg aiul deck equiiniient is given particular attentioi.

heavy foundation under the deck. If
fitted on a steel deck the deck plates
should be increased in thickness or
have a doubling plate under all bitts.
On wooden or concrete decks a pad
of timbers from lj4 to 3 inches thick
should be under the 'bitts. The metal
posts are cored out to decrease the
weight.

Sometimes in small vessels the tow-
ing bitts are single or double hard
wood posts with rounded corner edges.
These wooden bits extend through the
deck planking to the floors or keelsons
and are through bolted to a heavy deck
beam fitted against their after sides.

Large tugs may have a mainmast
to which is secured a strong steel
hook for towing. The hawser is
looped over this hook and a hinged
"keeper bar" is closed over the hook
opening so the hawser cannot jump
off the hook.

The towing bitts thus far discussed
are located aft of the deck house or
trunk and are used only when the
towed vessels are astern of the one
doing the pulling.

Three precautions should be taken :
(a) Locate the bitts as far forward
as practicable so that the vessel will
not be difficult to
steer if the tow
"yaws" or swings
to one side or the
other.

(b) Make the
deck under the
towing bits extra
strong.

(c) If the vessel
does much towing
in open water, have
the bitts high
enough above the
deck so that the
hawser may not
bear too heavily
on the rail at the
stern, in which case
following seas
would come on
deck.

Large deep sea
tugs have a towing
engine which auto-
matically winds or
pays out the hawser

The Dcsian and Conslnntion of Pozver Work Boats

keeping it at a constant tension. They
also have a yoke or frame of struc-
tural or cast steel which guides the
hawser to the bitts or towing engine
and keeps it raised above the stern rail.
The towing hawser when not in use
may be coiled on the ash grating over
the rudder quadrant at the after end
of the deck, or it may be reeled on

In harbors and fairly crowded wa-
ters the barges are towed alongside
of propeller-driven power boats and
"side bitts" (Fig. 90-B and C) are
fitted at about one quarter of the ves-
sel's length from the bow and stern
at each side of the deck. With a
high bulwark rail the bitts are as in
(Fig. 90-B), the rail timber being wid-

(A)

.Deck

(SJ

l^^'^"' ^fe/.,

[fO Ekref/o/)

JUL

FIG. 89— ANCHORS, CHOCKS AND HAWSE PIPES

spools under an overhang of the deck
house top, thus being kept out of the
weather. All power workboats should
have towing bitts and hawsers for use
in emergency.

On the western rivers of th? United
States the towboats having stern paddle
wheels push the barges which are se-
curely lashed together and "stacked"
against the wide forward deck. Two
strong posts called "stack knees" (Fig.
90-E) brace the towboat bow against
the nest of barges.

ened locally to embrace them. Flanges
on the bitt casting provide for bolting
securely to the rail, bulwark and deck.
Sometimes the bitt has only one post
instead of two as shown and the cast-
ings are always cored out for light-
ness.

With a low bulwark rail or an open
pipe rail, ordinary mooring bitts (Fig.
90-C) may be used for towing. In
small wooden power boats the side
bitts may be hardwood posts through

the deck and securely bolted to the
framing, clamps, etc.

A set of bitts are usually located
on the deck center line near the bow,
for riding at anchor or towing when
backing away from the vessel being
pulled. These bitts of steel or wood
usually have the windlass secured to
them in vessels up to about 130 feet
long. Larger vessels have an inde-
pendent windlass.

Niggerhcad on Tugboats

Finally the practice of extending the
stem or apron up to form a "nigger
head" (Fig. 90-D) is common in tug
boats. This may be of steel bolted
on top of the deck and extending above
the rail, or of wood as shown on the
sketch. The size of a bitt is indicated
by the diameter of its posts.

"Cleats" or cavels (Fig. 91-A) are
used for securing mooring lines on deck
or for running lines and lanyards on
spars in the rigging. They are of cast
steel or cast iron and their size is
stated as the length in inches from
tip to tip of horns. When on deck
they are located at the quarters just
inside of the water way or the deck
margin.

The lines lead from the cleats on
the mooring bitts through "fairleaders"
or "chocks" (Fig. 89-F and G) (Fig.
91-B and C). "Mooring ports" or
"Bulwarks Chocks" are similar to Fig.
89-F, but usually lead straight through
instead of at an angle as shown for
this special one which is at the bow.

Open chocks (Fig. 91-B) are usually
one forward and aft of each mooring
bitt or cleat. Closed chocks (Fig.
91-C) are less frequently used due to
the difficulty of passing lines through
them. They were designed to prevent
the line from jumping out.

Roller Chocks on Large Vessels

Roller chocks (Fig. 89-G) are mostly
used in large vessels and have been
previously described. They are apt not
to function if care is not taken to keep
the roller well oiled and the pin clean.
Roller chocks are sometimes fitted on
top of the rail aft and the towing hawser
led through instead of being free to
slide on the rail log from side to side.
If the towing hawser rests on the
wooden bulwark rail in towing, there
should be two half round or half oval
iron bars on top of the rail to pre-
vent excessive wearing of the wood.
These guard irons are fastened to the
rail log with countersunk head screws.

Scupper Ports for Draining Decks

Decks and housetops exposed to the
weather are provided with means for
draining the rain or sea water by
"scuppers" and "freeing ports."

Scuppers are openings in the deck

Anchors — Toiving — Deck Drainage

at the low points. They consist of a
deck casting with a slotted bronze
strainer and have a pipe leading down
which carries off the water. Light su-
perstructure decks and house tops have
the scupper pipes discharge onto the
lowest weather deck. The downcomer
pipes are of copper or lead, from
1 to 2 inches in diameter and spaced
at intervals of 6 or 8 feet around the
edge of the deck. Deck house and

trunk tops have the pipes close to the
house sides and turned outward at the
bottom ends. Light upper decks with
wide overhangs have the scupper pipes
close to the stanchions supporting these
decks at the vessel's sides.

The lower weather deck in small boats
is drained directly through long shal-
low ports cut into the log rail. If
there is a ridge at the deck margin,
caused by the deep margin planks, the

£on*/Te/t/ioa/ jE/evaf/o/f

T.'HJr Si/ffif c/oy^aif

3/0£ "Bji-r

13)

if}

Ccj

Trtn »i/*ree S/eytff/e n

/^/^^er //eaaf

) (

'— — —tmaa

d>nf/T'i/t///7a/ /fv^»7//^

II
ii

^-,

-Tl
II
'I

Elei/af/'orr

(A)

■p/an

Cleat

Elevat/oy;
T/an

C/70C/C

cle vat/on

C/ojea'

Cfyoc/c

FIG. 90— TOWLNG BITTS A.ND KNEES

FIG. 91— CHOCKS AND CLEATS

waterway thus formed is drained by
scupper openings with strainers. Pipes
lead from these openings down into
the hold and out through the vessel's
sides. The main deck scuppers in steel
vessels are usually elliptical to fit
between the waterway angles and still
be large enough to carry off the water.
The lower end of the scupper pipe at the
ship's side has a casting with a pro-
jecting lip and a flap valve to pre-
vent sea water from coming on deck
through the scuppers. If scupper pipes
have right angle turns in them, there
is a screwed plug at each corner for
cleaning out purposes.

Freeing ports are large openings in
high bulwarks to quickly free the
deck of water which comes aboard
through waves. The ports sometimes
have a hinged flap opening out-
ward, but modern practice is to just
cut a large opening and stiffen the
edges with a bar. A grill of iron rods
is fitted over such open ports.

The Design and Construction of Power Work Boats

Typical "Handliner"
Power Fishing Boat

Fleet of Seine Fish-
ermen and Hand-
liners at Boston
Fish Pier.

Unloading a Catch
at the Fish Pier.

Crew Opening Mus-
sels and Baiting
Trawls. There are
400 Hooks to Each
Tub.

CHAPTER XVI

Tanks — Auxiliary Machinery — Quarters

CANKS may be used for carry-
ing liquid cargo, fish, fuel,
potable (drinking) water, lu-
bricants, and to afford a stor-
age hydrostatic head in gravity plumbing
or heating systems.

Large steel vessels have parts of the
hull especially constructed to form
cargo, fuel and drinking water tanks.
Such construction has been consid-
ered in previous articles. Concrete
vessels also have their tanks formed
by the hull.

Wooden vessels are not used for
liquid cargo to any extent. While
large tanks have occasionally been
built in such hulls by calking the
wooden ceiling and bulkheads, the
practice is not considered advisable
because the water is acting on both
sides of the hull structural surface so
that deterioration is more rapid.

As a rule the tanks in wooden hulls
are separate watertight steel compart-
ments. These may have flat sides,
properly formed to fit into the hull
and re-enforced by stiffening plates, or
else they may be cylindrical drums
which are riveted or welded.

Built-in tanks have their sides, top
and bottom re-enforced by angle stif-
feners at two-foot intervals, while
transverse and longitudinal swash dia-
phragms spaced six to twelve feet
apart, prevent excessive motion of the
liquid contents. Swash plates have
holes to permit flow of the liquid
through them but not enough metal
is cut away to prevent their reducing
the "wash." The flat heads are
flanged to the side plates and the
plate edges should be planed before
calking.

Heavy transverse foundation tim-
bers or "cradles" support the tanks
as indicated while chocks at the sides
and ends prevent lateral motion. For
painting or coating of tanks see Arti-
cle XII.

Cylindrical tanks are composed of
a rolled shell with a lap riveted longi-
tudinal seam and "bumped" or
"dished" heads. Some tanks are
"seamless welded," meaning that they
consist of two deep capsule shaped
ends with a circumferential seam at
the middle of the length. This seam

is welded and re-enforced by an ex-
ternal butt strap, also welded on. The
dished heads have a spherical form
and may be welded or lap riveted to
the cylinder shell.

All tanks should have filling pipes,
drain pipes, gage pipes, vent pipes
and manholes or hand holes.

Vent pipes should lead to the out-
side air in petroleum tanks and should
have a return bend at their upper end,
fitted with a wire mesh screen. Natur-
ally the vent should connect to the
highest point in the tank.

Filling pipes may lead to screw
plates in the deck arranged to re-
ceive the contents of the tank through
a hose or a large funnel with strainer.
If such a pipe is too long there is
danger of its breakage through un-
equal expansion and vibrations of the
hull and tank top. Therefore, the fill-
ing pipe sometimes ends just below
the deck plug and has an independent
cap. Such a filling connection may
serve as a vent for water tanks if
small holes are drilled just below the
cap. ;

Gage connections vary according to
type of measuring instrument used
and are sometimes dispensed with if
the contents are measured through the
filling pipe by means of a calibrated
sounding rod. In this case a small
re-enforcing plate should protect the
tank bottom where the rod strikes.
The kind of gages depend upon size
of tank and accuracy of measurement
desired. Gage columns of the simple
tubular glass type are subject to
danger of breakage and should be

protected by vertical rods or a ver-
tically slotted metal pipe around the
glass columns. Reflex gages consist
cf heavy plate glass in a metal frame.
The front glass has vertical "V"
grooves in it and causes the liquid to
appear dark as it rises between the
two glass plates. Float gages have a
twisted metal ribbon extending from
a horizontal dial in the tank top to
the bottom of the tank. The upper
end of the ribbon strip has a needle
attached. A small cork or hollow
metal float slides up or down the
ribbon as the level of liquid varies,
but the float is prevented from turn-
ing by vertical guide rods. As a re-
sult the ribbon turns the pointer as
the float rises or falls. Pneumerica-
tors are frequently use^ in large tanks
and afford the advantage of having
the tank contents observed at some
remote point.

Drainage connections are for suc-
tion pipes to the point at which the
tank contents are utilized or dis-
charged. Sometimes a screw plug is
fitted to a flange at the lowest point
so that the tank may be entirely
emptied and dried out.

Sediment chambers may be fitted
to fuel tank discharge lines to catch
and retain impurities or foreign mat-
ter. The suction is at a point near
the top of such chambers and a clean
out plug is at the bottom. This pre-
caution is not considered necessary if
the fuel is strained through fine copper
screen as the tank is fitted.

All pipe lines should have offsets or
bends to permit of expansion without

FIfi. 02— KUi;i. oil WATKI! TANKS, FLAT SIDE TYPE

/:>

7(y

The Design and Construtiou of Pozvcr Work Boats

Vcni Pi/ic

Cvt/NDPICflL fVEL T/INKS

Iti fMGiME Room Wings

ruH Pipe

( ^ yCever Plate

DCTMIL /IT /I
OCl/IRO STRIPS WHCflE
FUEL SUPPtV P/PE TO
EN&IHE CWOSSES FLOOR

'vel FromT^nk

fuel Line
' To Enyt'n*

Screu/ed
' OfCK Plate

llUnj pijie

3EDIMEMT CH/IMDEff

DETAIL C
Deck C/isting &
Filling Pipe

FIG. 93— INSTALLATION AND EQUIPMENT OF FUEL TANKS

Straining or breaking the pipes and
connections. Valves and pipes should
be within access at all times and
clearance around the outside of tanks
should be sufficient to permit of clean-
ing and painting the tanks and sur-
rounding hull structure. No pipes
should be threaded to the tank plat-
ing but riveted flanges of cast steel
or heavy plating should take the
screwed connections.

Auxiliary machinery for hoisting
purposes has been discussed in a
previous article. That for pumping,
lighting and miscellaneous purposes is
located in the engine room if possible
and is usually a part of the engine.

Electric Generaling Sets

Electric generating sets vary from
one-half to five kilowatts capacity and
are driven by independent internal
combination engines or by a silent
chain or belt from the main engines.
Independent sets of standard com-
mercial makes are preferable, since
they do not require running the main
engine if light is desired when the

Ca.r\vas Pachtnf tn
White Letd

MM y»ii»!

Hvll Pianktnf

OCTAIL OF
IHLET CONNECTION

FOR Pipe Suctions
Fho/i 5Ef\

vessel is not under way. The ca-
pacity of the set varies with the num-
ber of lights on the vessel. A stor-
age battery is usually "floated in the
line" from the generator, so that it
becomes automatically charged and
may afford current when the genera-
tor is idle. A switchboard of slate or
other nonconducting material is fitted
near the generator and has the usual
volt meters, ammeters, rheostat,
switches, fuses, ground lights, auto-
matic cutouts, etc. The various cir-
cuits should be arranged to lead direct
from the switchboard and to be inde-
pendent. This is particularly im-
portant in the case of the running
lights and the searchlight. A "tell-
tale" should be in the pilot house so
the helmsman can see that the run-
ning lights are in order. All running
lights if fitted for electric equipment
should have duplicate oil lamps which
are used in case of emergency.

The number and location of run-
ning lights are regulated by the Bu-
reau of Navigation, Department of
Commerce, Washington, D. C. They
vary with the size and type of vessel.

Searchlights may be of the arc or
the incandescent filament type. The
latter are considered ample for the
average small work boat, since their
power consumption is less and they
are not expensive or complicated.

Lights in the living quarters should
be tasteful and ornamental. Frosted
globes add to their attractiveness and
soften their glare.

Lights in machinery spaces, pas-
sages, holds and on deck are in vapor
tight fixtures ard should be guarded
by wire. In the engine room, cargo
holds and tank spaces, plugs should
be fitted so that portable hand lights

may be connected when needed. The
cable for these lamps should be suf-
ficiently long to insure being able to
see any point which may require ex-
amination or repairs.

If there is electric power at the
docks where the vessel ties up, and
the voltage of the ship's circuit agrees
with that on shore, it is well to fit
plugs outside the deckhouse so that
current may be taken from the dock
lines if the boat is tied up for ex-
tended periods.

The wiring on decks and elsewhere
except in the living quarters should
be in metal conduit, with standard
metal junction boxes. Wood molding
may be used in the living spaces.

Pumps and Drainage

Piping for the "Pumping and Drain-
age Systems" has the following uses:

(a) Draining the bilges,

(b) Filling and emptying water
tanks,

The main engines are usually fitted
with two water pumps of the plunger
or the centrifugal type, driven from
the crankshaft or the camshaft. One
of these pumps circulates the water
for cooling the engine cylinders. It
draws its supply from overboard
through a sea connection on the hull,
near the turn of bilge. Be careful
that this location will provide against
danger of stopping up due to the ves-
sel's grounding and that it will always
remain below the water. A strainer
covers the pipe opening to prevent
solids from entering and clogging the
pipe line to the circulating pump. A
valve in the suction pipe, close to the
sea connection, provides for closing
off the sea water in case of damage
to the pipe line, or if the pump is to
be used for draining the bilges.

The cooling water passes from the
circulating pump to the cylinder jack-
ets and discharges overboard at or
near the water line. Frequently the
cooling water discharge pipe is tapped
into the exhaust pipe from the mam
engine.

The suction pipe to the circulating
water pump may be arranged to draw
from the bilges by connecting to the
bilge manifold. This gives the boat
additional pumping facilities in case
of emergency, when the sea injection
valve may be closed and the bilge
water discharged through the cylinder
jackets of the main engine.

The second pump above mentioned
is not fitted to all engines particu-
larly in the smaller sizes. It serves
as a bilge pump, drawing directly

Tanks — Auxiliary Machinery — Quarters

from the bilge suction pipe lines and
discharging overboard. It may also
be piped to the sea connection which
admits water to the circulating pump,
and thus used to provide sea water
on deck for washing down or fire pur-
poses.

Power tugs from about fifty feet
upwards in length usually have an
auxiliary gasoline engine which drives
a generator and sometimes an air
compressor and water pump as well.
This pump is piped to the bilges, the
fire and deck service and the sanitary
service, through a manifold in the en-
gine room.

A hand-operated bilge pump should
be fitted on all power boats.

The sanitary system is piped to
flush closets, urinals, for water supply
to baths, wash bowls and even for
cooking purposes, on boats operating

tuiaUc o/ Hull

DETAIL OF
SOIL PIPE DiSCHnROE
CONNECTION

Noie: Drain fiit>^i end
Scupper Ouil'is jrein levels
w<it mbaue wnier Jine hM4
not i^ fitted withfltp vtlve.

in fresh water. Salt water vessels use
sea water for flushing and bathing
only, fresh water being taken from
the tanks for cooking and potable
purposes.

Pressure is provided through an
overhead gravity tank which may be
on top of the deck house or the cabin
trunk. Connections to the sanitary
supply tank are a filling pipe, a dis-
charge line, an overflow, a vent pipe
and a drain plug. It is essential that
the tank be protected against freezing.
Boats with a ventilating stack may
have the tank in this.

Mention has been made of pipe con-
nections on deck for washing down
and fire uses. Brass capped plugs at
the sides of deck houses, with hose
racks on the bulkheads nearby, should
be on boats from about 75 feet long
upward. Vessels smaller than this
have fire buckets in racks on deck
and chemical fire extinguishers, lo-
cated where readily reached in case of
fire.

Fire Losses Are Preventable

The majority of fire losses in power
boats are preventable by proper de-

sign and the observance of due pre-
caution when in service. Most fires
are due to one of the following:

(a) Improper ventilation of the fuel
tank and engine room.

(b) Leaks in the fuel pipes and
fittings because no allowance is made
for vibration and expansion, or the
pipes and fittings are inaccessible for
repair.

The first of these causes will be
taken up under ventilation; the second
has been discussed under fuel piping
and the third may be avoided as fol-
lows. Fit a sheet metal drip pan
under all fuel and oil tanks and under
the engines. This pan may be of
black or galvanized iron or copper,
and of width and depth to catch and
retain all drip from the machine under
which installed. A slight drainage
slope should be given the bottom of
the pan and there should be a large
well or "sump" at the low end, from
which the drippings may be pumped,
bailed or swabbed.

All water piping may be galvanized
wrought iron with malleable screwed
fittings. Valves should have compo-
sition seats.

Air pumps, supplying pressure for
starting the main engines, blowing the
whistle, affording a head in the water
or fuel tanks when these are low
down in the hull, are sometimes
driven from the main engine or by the
auxiliarj' gasoline set.

Power boats in northern waters
should have some form of heating
system. When less than 50 feet long
small oil flame heaters, securely fast-
ened to the deck may be in each
compartment to be heated. The deck
and bulkheads near all heaters should
be protected against the heat by a
sheet of asbestos board covered with
sheet metal.

Larger boats have central heating
plants of the hot water or steam type,
with piping to the radiators in heated
spaces. Such heaters may burn coal
or oil and should be in the engine
room or the galley. A small galvan-
ized or black iron smoke pipe carries
the heater gases to the stack, when
such is fitted. Otherwise the smoke
pipe projects above the cabin or trunk
and has a metal cap or hood to ex-
clude rain water. Sometimes this
hood turns with the wind thus in-
creasing the draft by ejection effect.

There should be about one square
foot of heating surface in the radia-
tors to each fifty or seventy cubic
feet of space to be heated.

Hot water systems require an ex-
pansion tank located in the top of the
engine room or the stack. This tank
has an overflow connection to the
deck outside and is piped to the radi-
ators and to the cool water inlet of
the heater. The heater should be be-
low the level of the radiators if pos-
sible, so that the hot water leaves the
top of the heater, flows upward
through the radiators to the expansion
tank and then down to the heater
again.

A coal bin or fuel tank is located
close to the heater.

The heater is provided with the fol-
lowing fittings:

Thermometer,

Pressure gage.

Water gage,

Safety blow valve.

Damper,

Drain plug.

Air relief valves should be on all

Stfniner

^ Sheet
fieUL

Scretved .
Flanged

DET/\\L OF

scupper from tiled
Toilet sppiCe ,

radiators and the entire system should
be carefully drained through cocks at
the low points, in case the vessel is
laid up during freezing weather.

Steam heating systems are similar
in arrangement and fittings except
that tlie expansion tank is lacking.

In large vessels, thermostatic con-
trols may be fitted in the heated com-
partments to automatically regulate
the temperature.

Radiators vary from ordinary pipe
on brackets, to cast iron, pressed steel
or brass ones of the upright or the
wall type. Pilot house radiators and
piping within ten feet of the compass
should be brass, because of the effect
of iron or steel on the magnetic
needle.

Insulating pipe covering should be
on all heater pipes, on the exhaust
pipes from machinery and on all hot
pipes where extreme temperature will
endanger personal safety or result in
loss in efficiency.

Tubular boilers on large diesel en-
gined vessels sometimes derive their
heat from the exhaust gases of the
main engines, generating steam for
auxiliary engines and for heating.

The Design and Construetion of Power Work Boats

Oure.7

/l,/e P/iiiM£

FIG. 95— Bl ILT-IN UKFIilCKIlATOIi IN (AniN TKUNK OF 50 TO Tu-FOOT I'OVVEU BOAT

Vessels of this type use electrical
pumps, winches and other auxiliaries,
the current being supplied by a gen-
erator driven by a diesel engine.

Plumbing Fixtures

Plumbing fixtures are too often not
installed where their presence would
introduce low additional cost while
affording real comfort and sanitary
surroundings. This applies to nearly
all power workboats, which should at
least have a self-flushing water closet
and lavatories with running water.

If the crew is quartered on board
it is imperative that bathing and gal-
ley plumbing fixtures be fitted; for a
clean and well fed crew means a neat
and well kept ship.

Water closet bowls should always
be located in a well lighted and ven-
tilated space, partitioned off from the
rest of the living quarters by odor
tight bulkheads. There should be at
least one bowl for every twelve or
fifteen persons. The discharge or
"soil" pipe should be large (at least
three inches in diameter). Too much
emphasis cannot be laid on this point,
for clogged bowls are a cause of dis-
satisfaction and disgust. The flushing
water should be taken from the sea
and the bowls located above the load
water line if practicable. This will
eliminate the necessity for pump type
closets if the boat has a sanitary pres-
sure system. Bowls if below the
water line, should always be of the
pump type.

Urinals are fitted in larger vessels
and should be of a type readily
cleaned, not subject to clogging.

All sanitary fixtures should be as

close to the ship's side and to the
source of water supply as practicable.
Lavatory and toilet spaces should be
easily entered without undue disturb-
ance of the privacy of living quarters.

Water supply pipes may be galvan-
ized wrought iron, with valves having
bronze stems and seats. Discharge or
"soil" pipes may be wrought iron or
lead, terminating in cast iron flap
valves at or near the water line on the
hull. If the pipes have bends (which
should be avoided) there should be a
clean-out plug at each turn in the
pipeline.

The deck in toilet spaces should
never be of wood or other material
which tends to absorb moisture and
odors. Tiling in cement or plain ce-
ment are best suited for such decking.
Wooden decks should be protected
against the likelihood of moisture
getting under the deck covering, by
having a watertight sheet lead, zinc
or galvanized iron pan fitted tightly
all around the compartment and ex-
tending at least up onto the bulk-
heads. This "flashed" metal should
extend at least six inches above the
top of the tile or cement. Plain ce-
ment decks in toilet spaces should
have portable gratings of oak or ash.

The corners of all toilet space decks
should be generously rounded (coved)
and drainage provided at the low cor-
ners by scupper openings having per-
forated brass strainers. Pipes dis-
charge from these scuppers into the
soil pipes or the deck scupper pipes.

Where bathtubs or showers are
fitted, these should be located apart
from the toilet spaces and should have
running hot or cold water. The sup-

ply for these is usually from the sea,
but on salt water ships fresh water
is from the ships' tanks and salt water
1.; provided as well.

Lavatories and sinks in galleys or
pantries should have spring faucets to
minimize waste of water. They dis-
charge into the soil pipes and some-
times into the bilge.

All toilet fixtures above mentioned
should be of porcelain enameled iron,
with nickeled brass fittings so they
can be kept clean and sanitary.

Hand pumps of brass or with brass
linings, are fitted to galley sinks from
the fresh water supply system.

In sone harbors the discharge of
waste from plumbing fi.xtures is pro-
hibitive and vessels navigating such
waters require a large tank in the
hold. The waste matter from these
tanks is forced overboard by com-
pressed air, steam, or a pump for that
purpose, after the vessel has got
away from the prohibitive waters.

Messing Equipment

Messing equipment is that devoted
to feeding the crew, including the
storage of unprepared food in store-
rooms and refrigerators; the prepara-
tion of the food in the galley and the
serving of the food.

Canned food supplies or those such
as rice, beans, flour, sugar, etc., which
keep relatively long without refrigera-
tion, are termed "drystores." Lockers
or storerooms with shelves and bins
for such stores may be located in the
hold and should be dry and well ven-
tilated.

Vegetables should be placed in
grilled boxes or bins, in the open air
if possible but with covered tops.
Such vegetable lockers may be located
on top of the cabin or trunk to which
they are securely fastened. They con-
sist of oak or pine slats with a rain-
proof hinged top. Vegetable lockers
of strong wire mesh are desirable in
larger vessels.

Small bins or jars in the galley
should be fitted to provide an imme-
diate supply for cooking.

Perishable supplies such as fruit,
eggs and other dairy products, meats,
etc., are carried in refrigerators. These
should be easily reached from the
galley and may be either built into
the ship or of standard commercial
type strongly secured in place.

Refrigerator capacities average from
2..S to 3 cubic feet of volume for each
person for which cold stores are pro-
vided.

CHAPTER XVII

Food Storage, Heating and Lighting

'MALL refrigerators in vessels
shorter than 100 feet, are usu-
ally cooled by ice carried in
a compartment within them-
selves. Larger ones are cooled by re-
frigerating machines, using ammonia,
carbon dioxide, sulphur dioxide, ethyl
chloride or dense air as the cooling
medium. The smallest of such ma-
chines have a capacity of one-quarter
ton of ice per day. They are driven
by electric or internal combustion mo-
tors.

The outside refrigerator walls are
of steel or wood, usually tongue and
grooved, from % inch to 1% inch
thick. The inside of these bulkheads
has a layer of tarpaper or building
paper. A layer of insulating material
is inside the paper and is from four
to eight inches thick. The best of
such materials is pure block cork,
usually fitted in two layers with the
seams staggered. Sometimes a sec-
ond layer of thick paper is between
the two thicknesses of cork, while a
final paper coat is always inside the
insulating material. Ground pressed
cork, mineral wool or even air cells
are often used to form the refrigera-
tor walls but these are not recom-
mended. The insulation should be
packed tightly and fastened by ce-
ment, «o< by nails or other metal fasten-
ings which conduct heat. The inside
refrigerator walls are of sheet zinc,
porcelain enameled iron, glass, or
wood soldered or cemented in place.

In designing refrigerators remember
that cold air from the ice or the cool-
ing coils always settles to the bottom
and replaces warmer layers. There-
fore, the ice or coils should be at the
top of the box to insure circulation.
The air in refrigerators should be kept
as dry as possible.

If ice is used it is placed in the
upper part of the refrigerator on a
metal shelf which has pipe drains to
the bilges. Air spaces above and at
the sides of the ice provide cooling
circulation.

Refrigerator doors are double rab-
beted with rubber gaskets. Small
boats may have refrigerator boxes
opening on top located in the holds
or under locker seats. A convenient

arrangement where there is a separate
galley, is to have the refrigerator in
one corner with its top just below the
windows of the cabin or trunk. The
ice and cold stores may be passed
through a window directly into such
a box. Still larger vessels with galley
on the main deck may have a door in
the deck house at the refrigerator.
Both these arrangements prevent the
soiling of interior of the cabin or
trunk when stocking up the ice box.

Dryslorcs

iftj-reiv J^AeT/f/^tiS -

seCT/OH TH/?U FffAMS of

FIG. 00— CONSTRUCTION OF KEFKIGERATOR
DOOR

hold and should be dry and well ven-
tilated.

Vegetables should be placed in
grilled boxes or bins, in the open air
if possible but with covered tops.
Such vegetable lockers may be located
on top of the cabin or trunk to which
they are securely fastened. They con-
sist of oak or pine slats with a rain
proof hinged top. Vegetable lockers
of strong wire mesh are desirable in
larger vessels.

Small bins or jars in the galley
should be fitted to provide an imme-
diate supply for cooking.

Galley ranges vary from small blue
flame kerosene stoves with one or
two burners to large ranges burning
oil or coal. The small stoves may be
in a drawer lined with sheet metal
so that the stove is out of the way
when not in use. A small fuel tank
is usually fitted to such kerosene
stoves and sometimes there is a small
hand operated air pump to generate
pressure in the tank.

Oil burning ranges use fuel oil of

heavy gravity and are used only in
vessels with diesel engines or in large
vessels. The burner atomizes the fuel
by air, steam or mechanical means.

Coal ranges are usually fitted in ves-
sels above 100 feet long. There is a
fuel locker close to such ranges and
they have a tank attached for heating
water. This may be piped to the hot
water sanitary system if desired.

All ranges are securely fastened in
place by screws, angle lugs, or stay
rods. There is a nickeled guard rail
on top of the ranges to prevent pots
and pans from sliding off.

The deck and bulkheads near ranges
are protected against the heat by
sheet asbestos covered with galvan-
ized iron.

A stack over the ranges carries off
gases and odors.

Dressers for Food

Beside the ranges, sink and plumb-
ing thus far mentioned, galleys have
dressers for preparing the raw food
for cooking. This dresser may serve
as a mess table with hinged stools
attached or arranged to stow under-
neath. Lockers and drawers under
the dresser and the sink afford stow-
age for cooking utensils. Racks and
shelves on the bulkheads are provided
for the dishes. These shelves have
covered fronts with a Y-shaped slot
in them so that dishes are put in at
the top and cannot slide out when on
tlie shelf. Cups and other china dishes
with handles are hung from hooks
underneath the shelving.

The decking of galleys in small
boats may be linoleum, while in larger
ones it is usually tile.

When meals are not served in the
galley there may be a saloon, although
this is not common in workboats.

Berthing accommodations are not
needed in boats which have short runs
but it is well to provide sleeping facil-
ities for emergency use. To this end
hinged bunks of galvanized pipe may
be installed in the forehold or even in
the wings of the engine room. The
berths may have lashed canvas or
spring bottoms and mattresses. Bed-
ding is stored in lockers nearby.

Sometimes cushioned seats or "tran-

fLtM

£LE\^Arie^

piQ, 97— INTERIOR OF STACK WITH TANKS

soms" are arranged to slide out form-
ing berths when extended. The cush-
ions are designed to fit the extended
transom and serve as mauresses.
Cushions are filled with hair or buoy-
ant fibre such as kapok. They may be
covered with leather, imitation leather
or velvet. The imitation leather is
recommended as being durable and
best for ordinary workboats.

Lockers, drawers and shelving
should be provided wherever possible
by utilizing unoccupied corners or
spaces under berths and seats.

Means of Ventilation
The usual means for ventilation are:
(a) Cowl ventilators, (6) mushroom
ventilators, (c) wind chutes, (d) vent
pipes or "goosenecks," (e) skylights and
hatches.

Cowl ventilators may be fixed or
portable and are arranged to be turned
'into the wind" by shafting and gears

^^n// VENTILATOR

The Design and Construction of Power Work Boats

operated from below or by handles
on the cowl itself. They are of sheet
iron, galvanized or painted. Small
cowls on yachts are sometimes of pol-
ished brass. The cowl is mounted on
a fixed trunk fastened to the deck by
an angle ring. This trunk may extend
to any desired distance below the deck
and the part below the deck ring may
be circular or rectangular. Sometimes
it is necessary to offset the trunk be-
low decks so it will not prove an ob-
struction. The cowl opening is usu-
ally twice the diameter of the ventila-
tor trunk and the upper edge projects
slightly beyond the bottom of the
opening. The metal forming the cowl
is bumped and welded or riveted to
shape. A split pipe or half round bar
re-enforces the edges of the cowl
opening.

Mushroom J'cntilators

Mushroom ventilators are not "wind
catchers" as is the case with the cowl
type. They are merely "up comers,"
meaning that they release impure air
but do not admit a fresh supply. They
consist of a short pipe fastened to the
deck with an angle ring. A screw
down cap covers the top of this pipe
and seats on a watertight rubber
gasket or a ground joint. A central
rod with acme or square screw threads
ill a guide is turned from below by a
handwheel or crank, thus raising or
lowering the cap. The cap projects
over and down around the outside of
the pipe, so the vent may be opened
slightly in rainy weather. Mushroom
vents may be of cast steel or bronze.
They are usually fitted over toilet
spaces or living quarters where mild
circulation of the air is preferable to

i!l^"

/^USHf^OOM
V£NT/LATOf?-

H/)NOLei To

'7a Peer

Ma/^pl£- To

FIG. 98— VENTILATING F,QUIPMENT

PL/IN \//ewaf='

11 G. 99— VENTILATING EQUIPMENT

the direct draft afforded by the cowl
type.

Types of IVindchutcs

Windchutes are of two types; the
canvas ones for ventilating holds and
other spaces not requiring permanent
vents, and the "airport type" which
may be used in living quarters.

Canvas windchutes arc used in cargo
vessels and are simply a long canvas
trunk which has an opening near the
top. Wing flaps at the sides of the
opening help catch the air and force
it down through the trunk. The en-
lire canvas windchute is suspended
from the mast or rigging by its
hooded top and the lower end passes
through a hatch into the compartment
which is being aired out.

Airport windchutes are of galvan-
ized sheet iron, scoop shaped and de-
signed to be pushed through open
airports so that air will be deflected
laterally into the compartments of the
hull. They sometimes have screens
at their inner ends.

Ventilators of various types are sold
by ship chandlers in stock sizes.

Vent pipes or "goosenecks" are
placed over tank spaces and consist
of standard pipe extending above the
deck with a return bend at the top.
A standard pipe flange connects the
lower end of the pipe to the deck.

Forced ventilation is employed on
large vessels but not in the conven-
lional power workboat. Such a sys-
tem has a central blower plant taking
air from vent cowls and forcing it to
remote spaces in the hull through
sheet metal ducts or conduits.

.'\ few of the cardinal principles of
ventilation might well be discussed
and should be borne in mind when
designing power workboats.

First: Warm and impure air Is
ligliter than cool fresh air. Therefore,
the supply ventilator trunks should
lead well down into the ventilated
compartment, while exhaust vents
open from the highest points therein.
Skylights form good exhaust but poor
supply ventilators.

Second: The motion of air currents

Food Storage, Heating and Lighting

/■

CAifi/'i LiisMmo To

S'Pear'I'MSXL

x-i. i

H/N6£P -P/P^ S^PTH-

gC/^^^x <Se'r.

c/^ass secT/a/r or
5LIPIN(S TRAN50P1 B^PTM

H//VC7fP Tf?AN50M BfRTH

FIG. 100— PIPE AND TRANSOM BERTHS

inside the hull is from aft forward so
that supply vents should be at the
after end of compartments and ex-
haust vents at the forward ends.

Third: A mild air current well dis-
tributed is more effective than a

strong current which is local. Do not Fourth: Gasoline fumes are heavier

forget the corners of compartments than air and tend to accumulate in

and see that the circulation is diag- the bilges. Arrange for circulation

onally upward by staggering the sup- low down in engine or fuel tank

ply and exhaust vents about the com- spaces by using an open rather than

partment's centerline. a ceiled type of structure.

The Desifin and Construction of Poivcr Work Boats

jMary p. m:rn, power fishing sciioonkr

Owned by Cspe Aim Cold Storage Co. Equipped with 80-horsepower Wolverine engine.

Under command of Capt. Patrick Murphy . This has been

one of the most successful craft in New England waters

CHAPTER XVIII

Painting Structure and Sheathing

•EASURES must be taken to
protect a boat's structure
against the various elements
tending to cause deterioration.
Wood will decay or be attacked by
marine growth and animals. Steel will
corrode, decompose by electrolic action
or become fouled with marine growth.
First consider briefly the causes and
prevention of decomposition in wood.
Decay is brought about by micro-
scopic plants called "molds" or
"fungi." These tiny organisims grow
in the wood fiber as parasites, and
their growth is aided by oxygen,
water, heat and food, just as in the
case of other plants. If wood is kept
absolutely dry or constantly sub-
merged in water, it will not decay. If
the wood is in a moist atmosphere at
ordinary temperatures, it will decay
rapidly. If moisture is held in the
wood and cannot escape (as when
green timber is painted) decay will set
in. Sapwood decays more rapidly
than that from the heart.

Different Forms of Decay

Different forms of decay are "dry
rot", "wet rot", "sap rot", "brown
rot", and "blue stain". The latter is
not seriously detrimental to strength
of the timber and occurs in the sap-
wood of pine or other evergreens.
Such timber is treated by dipping
into a solution of 5 per cent solution
of carbonate of soda heated between
130 and ISO degrees Fahr.

Decay which exists in the heart-
wood of living trees, ceases when the
tree is cut and does not spread to
other sound pieces of wood nearby.

Softwoods which are exposed to the
weather wear away. This is known
as "weathering."

Where the Teredo Works

There are small marine animals of
various kinds in the salt waters of
warm climates which attack wood by
boring. The teredo worm is best
known of these. It has a hard horny
head, a long body and a feathery tail
of gills. When it has penetrated the
surface of a timber, the teredo works
along the grain and does not cross
seams which have been tarred or
calked. Fresh water kills the teredo

worm and vessels are sometimes taken
into rivers to eliminate the pest. When
properly sheathed with metal, hulls
are not attacked by the teredo or
that other insect, the wood louse
(limnoria). The teredo is not found
in cooler salt waters (temperatures
below SS degrees), nor in brackish
waters.

The wood louse is found along the
coasts of New England, the Gulf of
Mexico and the northern Pacific
states. It lives only in pure salt
water. Dirty water will kill it.

How to Prevent Decay

Prevention of decay in timber has
its initial step in seasoning or drying
out the moisture from the green
wood. Green wood contains from half
to three-quarters of its total weight
in water. Seasoned wood (air dried)
has from 10 to 20 per cent of its dry
weight in contained water. This re-
duction of moisture content lessens
the tendency for fungi to grow and
assures a minimum of shrinkage and
warp after becoming part of the
vessel's structure.

Timbers being air dried have a
tendency to split or "check." This is
minimized by painting or creosoting
the ends of the logs, or else by driv-
ing "S" shaped wedges about J^-inch
thick at the base onto the log ends.
Small timbers are sometimes put into
a concentrated salt solution where
they remain from a day to a week to
prevent their checking while season-
ing. They may be dried in bone char-
coal which also prevents checking.

Kiln drying is usually done in a
large heated and ventilated building
through which the lumber passes in
successive steps. It comes in at one
end as green wood and leaves at the
other end of the building in seasoned
condition. Soft woods can be dried
more rapidly and at higher tempera-
tures than hard woods, without loss
of strength.

Seasoned timber after incorporation
in the hull structure is protected by
saturating with various compounds to
exclude moisture and decay or by
coating with elastic waterproof pig-
ments. The saturating process is little
used in boat building, the preservative

chemicals mostly employed being
"creosote", chloride of mercury and
chloride of zinc.

Creosote is Best Preservative

Creosote (creosote oil or dead oil of
coal tar) is the best of these preserva-
tives. Owing to its penetrating odor
it is only used on vessels where the
cargo (if subject to taint) and the
living quarters are remote from the
treated timbers. Vessels such as shal-
low draft lighters or self-propelled
barges, which do not carry cargo in
the holds, may be creosoted. The
wood should be cut and trimmed to
fit before being treated. It is then
creosoted.

Creosote is a by-product from the
manufacture of coke or illuminating
gas. It is the residuum of tar after
the light oils have distilled off. Its
chemical composition is very involved.
It varies in weight as purchased and
the heavier grades are the best. The
timber to be treated has the coal tar
creosote forced into its wood cells
under pressure.

A number of compounds with trade
names such as "carbolineum" are ap-
plied with the brush as substitutes for
creosote.

The seasoned and cut timber is
placed in a heated chamber wherein a
partial vacuum is then created. This
expells moisture from the ducts and
cells in the wood and the creosote oil
is forced in to replace it. There are
various methods for performing the
processing, some more economical as
regards use of the fluid or less apt to
break down the structure of the wood
contributing to strength, than others.

Surface Preservatives

Surface preservative coatings for
wood are divided into (a) fillers, (b)
paints, (c) varnishes.

Fillers are used to close the pores
of woods which are to be given a
high polish. As such polished finishes
do not find general application except
for furniture, models, musical instru-
ments, etc., they will not be dis-
cussed here.

Paints for wooden surfaces contain
a basic pigment of lead or zinc, mixed
with an oil, a thinner and a dryer.

The Design and Construction of Power Work Boats

FIO. 101-BILGK KEELS AND SHEATHING

White lead, zinc wliite (oxide of
zinc) and leaded zincs (mixtures of
zinc oxide and sulphate of lead) are
used for the pigments. The lead and
zinc pigments are mixed in best
paints because zinc alone sometimes
causes check and scale, while lead
gives rise to scales or blisters. These
basic pigments in paint are improved
by adding small percentages of finely
ground crystal salts, barium sulphate
(barytes), oxide of silicon (silex) and
aluminum silicate (climaclay), being
most often used.

The desired tint is obtained by add-
ing colored pigments, the more usual
of which are lampblack, umbre, ochre,
sienna, chrome yellow and Prussian
blue.

Pure raw linseed oil is the best for
general paint use on wood. It causes
rapid drying and gives a hard finish.
Boiled and raw oils are mixed for
metallic paints.

Substitutes for linseed oil are
menhaden fish oil, used in marine
paints because it resists moisture. It
is apt to darken and to take dust.
China wood oil is used for water
proofing paints after being tested
with driers by heating. Corn oil and
cotton seed oil are sometimes used
but dry very slowly. Injurious effects
are brought about by use of petro-
leum or rosin oils. These tend to
produce checks and dry slowly.

Paints are sometimes sold in paste
form to be thinned when used by add-
ing oil. Chief among these are zinc
iron and lead oxide pastes.

Red lead is bought dry as a rule
and is mixed with free litharge to
get best protective results. About 10
to IS percent of litharge is added to
the red lead and causes the forma-
tion of a hard waterproof skin.

Turpentine is the most commonly
used paint thinner although petroleum
distillates of about the same weight
and quickness of evaporation some-
times give good results.

Driers when mixed with paint at-
tract oxygen of the air, thus hastening
the drying. They are made by boil-
ing manganese and lead oxides in oil.

Varnishes are made by melting tree
gums in oil and thinning with tur-
pentine. For outside work use a
"long oil" varnish, i.e. one containing
a large amount of oil. The best in-
terior varnishes contain small amounts
of oil. The best way to select a
varnish is by comparative tests under
working conditions or by experience
of the user or his friends. Many so-
called "varnishes" are not at all satis-
factory for marine use.

Painting Wooden Hulls

The following is a brief outline of
the usual painting procedure for
wooden work boats.

All parts of the structure to be
permanently covered over, such as
where timbers are joined or on the
inside of hull and outside of ceiling
in a ceiled vessel, should be carefully
painted before assembling. Where
wood and steel surfaces come together
a thick coating of red or white lead
and a layer of tar felt should be used.

All surfaces to be painted should
be sand-papered smooth. Knots
should be touched up with shellac.
Wood bruises caused by heads of fast-
enings should be plugged with wood
if large or puttied up if small. All
calking and filling of seams should
be done before painting begins.

First fill all seams over calking,
plane the surface fair and smooth,
mark on the "water line" which is

really above the level at which the
boat floats. This line is the upper
limit of the "boot topping."

The hull below water if not
sheathed with metal, should get at
least two coats of good copper paint,
but do not apply this paint to iron
surfaces.

The hull above water should receive
a priming coat and two finishing coats
of the selected color. Black, white,
dark green are the usual hull colors
used for work boats. Boot topping
is red or bright green.

Wood rails, fender logs, wood decks,
gratings and trim are usually finished
natural. All these except decks and
gratings should be varnished.

Deck houses and superstructure are
sometimes of the same color as the
hull above water. Often lighter shades
are used, white, gray, reds and buffs
being most frequently employed.
Canvas decks are finished in grays or
buff after laying.

Spars are usually varnished. Stacks
may be any distinctive color with
markings or insignia. Life boats are
of the same color as deck houses.
Rails, fixed awnings, life rings, etc.,
are mostly white.

Inside finishes should be in light
shades, such as white, french gray,
light green, light buff or natural
varnished.

Two or three coats are the usual
practice for all painted surfaces.

Painting Steel Structures

When steel is received from the
mills it has a coating of "mill scale"
or iron oxide which protects it
temporarily. After being built into
the hull most of this scale has rusted
off. Before any steel parts are riveted
together, clean the contact surface
with wire brushes and apply a thick
coating of red lead or other steel
priming paint of approved commercial
grade.

All surface irregularities can be
filled smooth with good trowel cement
made for steel. The first coat is the
red lead or other selected anticorro-
sive, after which parts above water re-
ceive two finishing coats of the de-
sired color.

The final coat below water line is
"anti fouling" paint containing chem-
icals, principally mercury oxides, iron
oxides and zinc oxides dissolved in
shellac and alcohol. Anti fouling
paints dry quickly and can be put
on during a day in drydock. The
usual marine growths are retarded in
their tendency to attach to the vessel
by these paints, but the effect wears
off and the paint must be renewed
after the steel has been scraped,
usually once every six or nine months.

Wooden hulls to be used in salt

Painting Structure and Sheathing

water infested by marine borers
should be sheathed with metal or
wood.

For a time sheet copper was used
as the only metal sheathing. It is
still employed in high class work but
not so extensively as heretofore, due
principally to the prohibitive cost of
raw material. Yellow metal (copper
alloys) has also found extensive use.

For power workboats an excellent
and relatively inexpensive metal
sheathing is galvanized sheet iron.
This has an added advantage of
greater strength and consequently
less danger of being torn when strik-
ing subsequent obstacles.

All metal sheathing is from 1/32-
inch (about No. 20 B. & S. gage) to
1/16 inches thick.

The wooden hull is calked and then
coated with thick pitch to the top
limit of the metal sheathing. This is
usually from 4 to 12 inches above the
load water line. A layer of tar felt
is sometimes used under the sheathing
instead of pitch.

The metal sheets are then fastened
on with tacks of similar material.
Care should be taken that all seams
lap and are tight. No buckles should
be in the sheathing and this is
avoided by fastening successive sheets
from the center to the edges. The
entire area of each sheet is studded
with tacks at intervals of four to six
inches in each direction.

Sometimes if the sheathing is on
too tightly it will split after the vessel
has been launched. This is due to
expansion of the hull planking when
absorbing a certain amount of sea
water. If there is no danger of dam-
age to the wood from borers where
the boat is built, it is well to launch
the hull before sheathing is applied
and later haul it out for sheathing
before delivery.

Hotv to Prevent Galvanic Action

If the propeller and other under-
water fittings are bronze when iron

-s-

M/^^
7'i^/yH

F/TC/t' £)/Z

FIG. 102— HOW WOOD SIIE.4THING IS FITrED ON WOODEN TIULLS

sheathing is used, or if of iron when
copper or brass sheathing is fitted,
protection against galvanic action in
salt water should be provided by us-
ing zinc strips on the iron or steel
parts near the copper or bronze.
These strips are rapidly eaten away
and must be renewed about every six
or nine months when the boat is
drydocked. It 'S best to avoid this
source of weakness by making all
underwater fittings of the same or
electrically similar metals.

Wooden rudders are sheathed in
the same manner as the hulls to
which fitted.

Where bilge keels or false keels are
used, they are apt to wear off or
break off frequently. The hull
sheathing should therefore be between
these appendages and the hull itself

and the sheathing for attached parts
is put on after they have been fast-
ened in place. (Fig. 101).

Wood sheathing was formerly used
in large wooden ships and is still
often employed on barges or very
heavy workboats. It is usually of the
same wood as the hull planking and
is fitted with the seams and butts of
the sheathing planks staggered with
those of the hull timbers. (Fig. 102).

The sheathing is bolted • to the
planking and is of about half the hull
plank thickness. Thick pitch is ap-
plied between the outside of hull and
the wood sheathing. Lag screws with
heads in recesses which are plugged
attach the sheathing to the hull planks
and should not extend through the
latter. Plank sheathing may be creo-
soted to advantage.

Tlie Design and Conslrnclion of Power Work Boats

" Elizabeth C." of Greenport, N. Y. A 16 ton Auxiliary Schooner owned by Capt. S. B.
Bushnell. Carrying a cargo of 200 bushels of potatoes. Mainpower plant four cylinder
40 H. P. Frisbie engine equipt with a Paragon Reverse Gear. In service seven years.

_ - CHAPTER XIX

How Concrete Power Boats Are Built

CONCRETE as a boat building
material has been employed to
some extent for years, particu-
larly in barges and for small
boats. The results in service of such
vessels have shown that a very long life
may be anticipated, that hull repairs are
practically eliminated and that such ves-
sels are highly satisfactory. When
one takes into account that very little
is known of this material in ship
work, such results would seem to
warrant a hearty endorsement of con-
crete small boats of every type, espe-
cially if num'bers are constructed from
the same design.

Several widely advertised boats
have been crudely designed although
successful with respect to strength,
carrying capacity and seaworthiness.
This may have resulted in a popular
impression that graceful designs can-
not be made of concrete. As a mat-
ter of fact, the concrete vessel can
be as well designed as those of other
materials and it possesses the added
advantage of being monolithic (seam-
less), a result striven for since the
origin of shipbuilding.

Concrete itself is a mixture of Port-
land cement with coarser aggregate
such as sand and gravel or stone.
In marine work, lighter materials are
sometimes substituted for the sand
and gravel, thus lightening the con-
crete without appreciable loss in
strength. In an ideal concrete the
particles forming the mass are grad-
ed as to size, the theory being that
the voids between the coarse ma-
terial are filled by the finer and that
the cement fills the smallest voids and
thoroughly coats each particle in
the mass. The ingredients are mixed
with water to a pasty consistency,
then poured between wooden molds
or "forms" and allowed to harden or

"set." The amount of water used
has a marked effect on the ultimate
strength, best results being when the
mixture starts to flow on a slope of
3S degrees from the horizontal and
will just stay on a shovel. Concrete
alone is strong in compression but
weak in tension. Steel rods or mesh
are therefore imlbedded in ,the
mass and so disitributed as to absorb
all tensile sitresses. This steel is called
the "re-enforcing" and concrete so
Strengthened is termed "re-enforced
concrete." Sheering strains are also
absorbed by the steel rods which
run in two directions; longitudinally
and transversely. Sometimes wire
mesh or metal lath is used in con-
junction with steel rods to prevent
formation of hair cracks. The steel
should be well protected against cor-
rosion since it will expand and crack
or "spawl" the surrounding concrete
and give rise to rust streaks. There
is no danger of this if the rods are
at a depth of 154 times their diameter
from the surface and have been well
coated with the cement. Pockets
and porous spots are avoiided by tamp-
ing the concrete around the steel and
vibrating the rods during pouring.

Since there is scant data to deter-
mine structure from previous boats
such as has been the case in steel
or wood designs, it is necessary to
make careful strength calculations
not only for hogging, sagging and
sheer but also to ensure ample
strength in resisting local strains.

First the usual weight, buoyancy,
load, sheer and bending moment
curves are calculated for both light
and load displacements with the ves-
sel assumed floating on a wave whose
length from crest to crest equals
that of the vessel. This well known
and lengthy calculation is clearly ex-

plained in books on naval architecture
as previously noted. In these calcu-
lations the vessel is taken as a float-
ing girder and the strength of sec-
tion most severely stressed is de-
rived from the formula:
S I

M =: C

Here M is the bending moment in
foot tons.

S is the maximum unit tensile or
compressive stress.

I is the moment of inertia of the
midship section.

C is the distance from neutral axis
to extreme upper or lower point of
the section under stress.

For cargo vessels and others of
ordinary form,

M = W X L

30 to 35

Where W is the displacement in
tons,

L is the length of vessel in feet.

30 or 35 are constants.

For vessels of unusually shallow
hold depth the constant may be as
low as 20.

The unit stress S is taken as 16,000
pounds per square inch tension for
re-enforcing steel and 850 pounds
per square inch compression for con-
crete. The section of greatest sheer
is at about one-fourth of the length
from each end. The greatest allow-
able sheering stress is 250 to 300
pounds per square inch in the con-
crete.

Longitudinal hull girders are in-
cluded in the calculations for moment
of inertia in hogging or sagging.
Transverse frames are not but should
be spaced as determined from local
"slab" calculations. Here the hull sur-
face is divided into rectangles prefer-
ably twice as long as they are wide.

The Design and Constriicfion of Poivcr Work Boats

Then from slab streng-th formulas
(see "Hoole & Johnson" on re-en-
forced concrete) the stresses and pro-
portions of concrete and steel are
determiined.

Deck strains in slab calculations
are obtained from deck loads or if
none are carried, a head of water of
four feet may be taken on the main
deck as representing a wave which
has come aboard.

Slab loads on the sides are due to
the combined downward thrust of
deck load and the side thrust of the
water outside, whose head is equal to
the molded depth.

Bottom loads are net from down-
ward weight of hold cargo, down-
ward thrust of deck load through
sides and stanchions and upward
thrust of buoyancy on outside due
to head equaling the molded depth.

In all calculations the number of
steel rods is found by assuming them
to be of standard commercial dia-
meters (from one-sixteenth of an inch

upward in round bars). After the
total sectional area of steel has been
calculated to withstand the tensile
and sheering stresses, the number
of rods and their spacing are de-
rived by dividing this required total
area by the area per rod of the
selected size. Usually it is most
economical to use rods between %"
and Yi" in diameter. Larger rods
are used in stanchions and framing.
Smaller rods are used in hulls of un-
usual thinness (less than 154" thick).

Types and disposition of re-enfor-
oing will be considered under "Con-
structions."

The theories and factors affecting
calculations for strength of re-en-
forced concrete are complex and can-
not be discussed here at length. Pros-
pective builders or owners are re-
ferred to the numerous articles and
typical plans on concrete ship de-
sign published within the past year.
Radical departures from these de-
signs or even conventional ships

FIG. 103— TYPICAL SECTION OF A CONXHETE HULL UNDER CONSTRUCTIO.N

where best results are desired should
be referred to some competent author-
ity on the subject of concrete ves-
sels.

Fig. 103 is a typical section of a
concrete hull under construction on
the building ways. Notice that the
concrete hull with its reinforcing bars
and structural framing is encased in
wooden molds or "forms" which are
supported by cribbing, scaffolding,
trusses and suspension rods.

The inner surface of the outside
forms is smooth and shaped to the
exact molded surface of the hull
These outer forms are of varied con-
struction but (for medium sized ves-
sels) are from 5^-inch to 2-in<;h thick
pine or fir planks with closely fitted
edges. Tongue and groove lumber
may be used on flat surfaces.

The framework and scaffolding out-
side of the forms should be strongly
designed but readily removable with-
out material damage to the timbers.
The forms may be in panels with
framing all around the seams to pre-
vent getting out of line. When the
hull has been molded and the con-
crete has hardened or "set", the forms
are removed or "stripped" by taking
down the scaffolding and sections of
form above the bilge, then un-
bolting and stripping the bilge forms ;
and finally the bottom forms are
stripped as follows: First take down
alternate cribs under the bottom, strip
the forms which the removed cribs
had supported, replace the cribs
under the exposed concrete, after
which the remaining cribs and panels
may be taken down and all the cribs
replaced under the bare hull.

The reinforcing steel is placed in-
side of and supported by the outer
forms. Then the inside forms are put
up as the pouring of concrete pro-
gresses. Owing to the cut up and
framed nature of the inner hull sur-
face these forms are in small sec-
tions so they can be quickly erected,
and also to permit their removal
through whatever size hatch, scuttle,
door or other opening may be in the
particular compartment after molding
is finished.

When the forms have been erected
and the reinforcing steel and all
fittings piercing the hull are in plact
the next operation is molding the
concrete. A coating or wash of lime
is applied to forms so they will not
adhere to the hull. Then the con-
crete is molded by (a) pouring, (b)
gunning or (c) a combination of the
two.

Before taking up molding, consider
the various types of reinforcing mem-
bers and their disposition within the

How Concrete Pozvcr Boats Are Built

concrete. The main strength is in the
basketlike network of rods encased by
the hull. This is augmented by
girders, beams, frames, floors, keel-
sons, stanchions, stringers and bulk-
heads; so that the surface of the hull
consists of a number of relatively
th'in panels or "slabs" supported by
the internal framing. Usually the hull
steel runs longitudinally and trans-
versely, although some ships have
been built with the rods diagonal and
and at right angles to each other.

There are many kinds of rods and
more methods of spacing and securing
them in place. Rods or bars are of
two principal kinds, (a) the plain
rounds and (b) the deformed bars.
The plain round bars are sufficient
for all practical purposes. Some en-
gineers contend that deformed bars
are more securely bonded to the con-
crete and perhaps this is so. At any
rate, the round bars if properly spaced
and secured give excellent service and
are therefore considered by the writer
as answering all requirements.

Regardless of the type of rod se-
lected these must be supported at the
correct distance from the surface of
the concrete and at their proper
spacing between centers in both di-
rections. If rods are not securely
held in place they will sag toward or
to the surface of the concrete, thus
becoming exposed when forms are
stripped and requiring the concrete
to be cut out at such spots so the
rods can be bent into place. The
rods are also apt to slide on one
another and become irregularly spaced
when molding takes place. This will
locally weaken the structure and pro-
duce undesirable voids. The sim-
plest and usual way to support bars
is by small concrete blocks or metal
clips between them and the outer
forms (Figs. 104 and 105). These
are spaced closely enough to carry
the rods without appreciable sag and
remain imbedded in the concrete after
forms have been stripped.

The rods are prevented from slip-
ping on each other by wiring them
together at alternate intersections or
by welding them at these points.
These are the methods usually em-
ployed for shore structures of con-
crete where most of the surfaces are
flat slabs of simple curvature. They
have been used in many concrete
vessels but are not considered the
most positive and economical for this
purpose. Some type of molded guide
bar of flat iron, angle or other struc-
tural shape which can be bent to the
curvature at any transverse section
and then slotted or punched to re-
ceive the rods, would be better.

//a/i>e fvK/fs

FIG. 104— MET.VL CLIPS USED TO SUPPORT LONGITUDINAL RODS

Such a system has been employed
satisfactorily in a number of con-
crete hulls with excellent results and
is shown in Fig. 106. The supporting
framework of transverse and longi-
tudinal angles is riveted together and
erected in the forms. The spacing of
these angles is about four feet in
each direction and they are very light.
The round bars are then threaded
through or laid into the punched
slots by unskilled laboi.

Bulkheads are constructed and re-
inforced the same as the shell. All
door frames, pipe stuffing boxes or
other aperatures must be located in
the forms before molding begins.

The number of rows of reinforcing

wires of light steel rounds (from J^
inch to y% inch in diameter) absorb
the sheering stresses in each member.
The girders and stanchions are calcu-
lated to withstand the loads on deck,
side and bottom slab areas which they
support. For stanchions this area
is the distance between them in each
direction. For frames it is their
spacing on the ships side in bending
and half the distance between ships
side and the first row of stanchions
in compression. For beams and gird-
ers it is their spacing times their
span. Details of beam and column
calculations are in texts on rein-
forced concrete construction.

Reinforcing rods should be as long

/,Vi/P£ I'^a/rir^i

v/zmzm^'^ '':':-:...mm^

FIG. 105— METHOD USED IN HOLDING RODS IN PLACE FOI{ POURING FORMS

depends on the steel required. A
general rule is that diameter of rods
ihould be less than one-fifth of the
thickness of concrete in which imbed-
ded. Fig. 104 shows two rows of
longitudinal and one row of trans-
verse bars. Figs. 105 and 106 show
one row of bars in each direction.
Sometimes wire mesh or expanded
metal is fastened to the outer row
of bars to prevent the formation of
hair cracks in the concrete.

Columns or "stanchions" and gird-
ers are constructed as in Fig. 107.
Extra heavy rods (from J4 inch to
1^ inches in diameter) take the prin-
ciple stresses being run up and hooked
over as shown. Stirrups and binding

as possible and the lapped or
butted ends should be well staggered
to prevent local weakening of the
structure.

The simplest way to join rod ends
is by lapping them at lleast 40
diameters and binding them with
wire. Special clamps are made which
grip the butted ends of rods similarly
to an outside pipe nipple. Best of
all the butted ends can be welded.

Since the girth of cross sections on
the hull becomes less toward the
bow and stern than it is amidships,
the rod spacing will vary throughout
the length of all types of vessels ex-
cept those with box sections such as
the simplest barges. When the rods

Ojre/z. Fbami

FIG.106— MOLDED GUIDE BAR PUNCHED TO RECEIVE RODS. THIS IS A VERY S.WISF.VCTORY
.METHOD USED WITH EXCELLENT RESULTS

The Design and Construction of Power Work Boats

/i-aXt-UL-i.lli-fili:liJT-i-'-'=KiJJ>yjJ.tiJ

FIG. 107— CONSTRUCTION OF STANCHIONS AND GIRDERS

Corracre Ponat Tiy6.

• SoHT^i-f-re

Bom Pure

Sect/oa/ 'Afi'

FIG. 108 AND 109— BOW AND STERN CONSTRUCTION FOR A CONCRETE WORKBOAT

come closer than half their spacing
amidships, they are dropped.

Rods at the stem and stern are
run over to the other side of the
hull and hooked into the steel struc-
ture at these points. Fig. 108 shows
bow construction for the workboat
of concrete. A "V" shaped steel
plate or a "T" bar form the cut-
water and are anchored into the con-
crete as shown (107-b and c). The
rod ends pass through the anchors
and hook over.

Stern construction is a point to be
carefully studied. If the conventional
"deadwood" type is followed, it is
necessary to support the forged or
cast steel stern frame by large steel
plates anchored into the hull. There
must also be a deep and heavy block
of concrete which contributes no
strength, reduces the cargo dead-
weight and is very crude.

Fig. 109 is a type considered
stronger, simpler and lighter. It was
used in two classes of concrete ves-
sels designed by the writer and has
proven successful. The line of counter
is produced to its intersection with the
keel '.vhich it joins by a circular arc.
The cross sections at any point of
this stern are "V" shaped. Care
should be taken not to have flattened
sections which would cause eddying
in the vessel's wake and render it
difficult to steer properly. The rud-
der is balanced and supported by a
cast steel bracket which has a large
palm through bolted to the hull. A
strut supports the propeller, being se-
cured as shown for single or twin
screw vessels. Iron pipe or sheet steel
tubes form the rudder trunk and also
receive the stern tube.

All hull fittings are similar to those
previously described and are bolted
through the concrete with wooden
pads on the deck to which they are
attached. Short lengths of pipe one-
eighth inch larger in diameter than
the bolts are inserted in the forms
before molding and the flanges for
attaching the fittings can be drilled
from templates taken of these pipes
after the concrete has set. No
anchor bolts should be used if pos-
sible and then only where the at-
tached equipment is not likely to need
removal for repairs or replacement.

Portland cement, sand, coarser ag-
gregate and water are used. The ce-
ment should be such that about 78
per cent of it will pass through a
wire gage of 200 openings per inch.
The sand should be clean (free from
loam or other impurities) and should
feel sharp when rubbed between the
fingers. The coarse aggregate should
be not over J4 inch in size while

How Concrete Power Boats Are Built

for hulls less than 2J4 inches thick,
it should be under % inch.

The proportions used vary con-
siderably but the following will be
found good for all watertight parts of
the hull such as shell, bulkheads, water-
tight decks, tanks etc.

Two-thirds of a part of cement, one
part of sand, one and one-third parts
of gravel. The aggregate components
are screened to size before mixing
and are thoroughly mixed while dry
before adding the water. Concrete
mixing machines are used for large
work and the work of molding should
not stop when it has been once start-
ed on watertight work. The mixture
or "batch" is poured through chutes
and conveyed to the proper point in
wheelbarrows. The first of these
schemes is best calculated to produce
good results.

The concrete is carefully tamped in
place and the reinforcing rods are
vibrated during pouring to release all
air bubbles and prevent formation
of voids.

A leaner and cheaper concrete (1
part cement, 2 parts sand and 4
parts gravel) may be used for stan-
chions, girders and other structural
members where strength but not
watertightness is required.

Fused shales and clays have been
used for hull concrete and found
amply strong. They result in a reduc-
tion of weight from about 145 pounds
for ordinary sand and gravel to be-
tween 100 and 120 pounds for the
fused aggregates.

Thus far the concrete has been
used for hulls only, deckhouses and
other superstructure having been of
wood or steel. There is, however,
no reason why concrete cannot be
used above decks except in the light-
est partitions.

There are many reasons why con-
crete barges and workboats should
be used in the future, especially if
the main points of design for par-
ticular sizes and types become less
numerous through compromise and
quantity of production.

Regardless of whether power boat
hulls are wooden, steel or concrete, the
writer feels that their present number

and types will be constantly increasing.
When we begin to realize the many
advantages of power workboats over
those propelled by steam, besides the
many uses which could profitably be
found for such craft, particularly in
the central and eastern portion of these
United States; when we awake to their
even greater importance than their nu-
merous blood sisters, the pleasure power
boat, a prosperous future presents
itself.

Power workboats could and should
be used wherever there are waterways.

They relieve congestion in crowded sec-
tions and can do the transporting more
cheaply than the rail or truck methods.
They promote commerce and can bring
the market to many now isolated pro-
ducers, whether these be farmers, manu-
facturers, fishermen, commuters or any
others who rely on cheap means of
transportation.

It is hoped that the details described
herein will work for more and better
power boats and will answer some of
the many questions constantly to be met
by the practical boat builder and owner.

M/i-l. /^TT/ti/Y/VSA-T^.

Co/iat^T:t Pb^k

/youjM.

t-^"-!-

yT^ir/^f-j-T.

■^ ■*«»*«« 'Vi/rA 'fv<j'>»i£r

^JTTrc ^-LMne

^'^^'jP^S^/vgvwr^it/.*^ j

/nACM/JXlS.-/ FhfMDAT/aMt.

riG. 110— DETAUa FOR ATTACHING MISCELLANEOUS FITTINGS

I uu u

APPENDIX I

Working Tables of Scantlings for Power WorKDoats

from 20 to 100 Feet m Lengtk, Including Tugs,

Tenders, and OtKer Heavy Duty Vessels

For Scantlings of Sizes
Between Those Given,
Use Averages to Stand-
ard Timbers

;aiiiiiiiiuiiuuiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiuiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiuiiiiiiiii!iiiiiiiiiiiiiii'iiiiiiiiiiiiiiiiii^

/rs:/^

2o'

/3-0'*6''O"

4,0'

Zo-oji/ag"

90'

j^^/fOrr

Ca<
/Z"/>1-6''S

p//rs

OAK
/2''k9"

OAK

/^'/V-ZZS

^ncfro/?i

/'£^*

/-4l7*

/- ire*

/- ZSO"
J- /On *

7-300*
/-/SO*

/•loo*'

/•Z60 *

J-iOO*

z-yaoo'

^^TTEA/S. C^K&O, /^M^-O

—

P/yre

PfME

P///S

PVAB

f'CeMreEi

/2-y

1>AX ^

p/ZlfE

P/Afe.

/8'c

P/Ar£
/3'C

/5V

II • /"^AjvPecK'

//2"/>}-/Z'i

z''/v-/^s

3'i"Ar-z's

^'/»-^"£

r'A<-(i''s

fO'^-^"S

/a'i'e''

//"k6"

/f/v-^'s

Mouse Ck T^Ufnt Top

/Z"

/r"

/8"

/s"

2Z'

20"

^0"

/'/z"M-/'i

3"^t-Z'i>

P'/re

i'M.Z-'S

p/Aiie

r- PiM£

/z"

/z'

/6"

/£'

/6"

CocfPir Crt.

HOLP /='iA-r

SPAiC f"

z'A/-/;i"^-

Pwa

^"M-Z'i

f>//V>£

4"jr2'

^'CkZ"

P/yy^e

^"a:2"

ff/Li,£ /rke^i.-

—

Oak

Oax

6"aS"

"l^/rrs-iSouA^PiJ-Tow/vs

.OAK.

AAK

dAiT/ieof

Ct<>j-r/iepiir

■fAi T /AOY
/6"ff0U&L£

/CiMi'PaueiE

CAirSTL
//"D31

CASrSTESC

CASrSTEEt.

/2''P3i.

M - ^/{>sae/^aa^///<i>

—

Oak
8'j<8"6iir<ui

7Ji"Sz/y6

CAsrSrEEi

OfiK

^"jtM"

OAK

6"Pacicie

aAK

/OWO'PSi

r'DBL

9^"P8L

CastJteei

/o'psi.

B^-^xi^r./^^^Zv^sJ

—

Oak

Z"7f*/£K

OAK

Oak

Oak-.
4"p

OAK

8'S

^'^£/UT/^aoir6

CAK

OAK

aA<

£'/>?■

Oak

OAK
S'PI

£?AK

/Z'AI

3.^M....7%z%^:j',,^

Tivo

/fj^pav

V~ivo

Pbiy/z

Tm/^eb

77/<fe£

nteBS:

/nOO^Z

zs-zw

2TV/tK

2. T/^/in

/ rwxK

TWO- sn/KK

2 TM/ck-

Z7f^u<

2TM/Ct<

2. V^/iir

/y,'P///£

P/Ay£
4"k<Z»

2 V* "

T/vs

Z'xAi^'

P//rE

pzM-£

y>vo-

-nyo

Tyyo

7>ya

i/^.T.ireei.-
' " - ^jLAre Tk/cifA/ess

Vs"(f^'-^-

'A"

'/¥"

^A'//'

//z.\i>yv'ii

Z'^z'j'^m"^

z''yoii

Z'ZA'>^!CL

J>2^/*^/^

3A2yz^^/

di^Sy'^i'l

PcOBtS

2\Z'lr%'Z.

txzr^'i

Z"x2^>/A

y*2h'A^i'i.

jx^'/t^^^/a

3)^3^'^

_ Minor. Piw^/aA/AL

P//rs

P/zr-E

P///S

7VAZM

/^//^Oie Pi V/jJOVAl -

Z"xZ"

zizy."

ZxS%,

Z'rS^"

Z"y^"

Z'x^"

Zlx't^"

2%^'

Z.'aM"

BoL ^/i/i/r ?i/9/V>f//v6

Oak

0>AK_
S"/V-3"S

Pi/fe
S'/H'Z'S

^J^-iK'^

" - ^T/Fref^E/^i

Sak

*-S^^cJ^

*'S^iJen

■^^CoTTOV

■O'^CaiVof^

*4'Ccrr.

^ifCarnvr

^d'orro/r'

^^rorzun

^^drra/y

„ Aw/yAv&s ai.Bj.07-

/• "

n n

*4. "

"^iCemrf

*6 .. .

iCarray

*6<rorrc)/^

"^^rroz*

*£<:imAy

f/f/B

P/ATE

^)i.'/>f,3"S

P//VE
S"Af. -^"i

P/A'£ ,,

P/A'S

OAK ^
S"M-iVyiJ.

P//rE

£"Af -■¥".<.

Pz/re
/a'x/o'

1pS/K£

P/^r/£
/ZjfZZ "

P//rc
Z"j.£"

P//re
2"rH/cK

z'T^/ck:

P/ys ^
Z'A-Tm.

P'/A'£

Ct^AiN - A/^cMaff

V/i-'fAt..

so i^Arr/

7i-pAr/f

Jfy"^ZfL

CLOCKS. Soy\^ee<fc/AxrEK

2,-0oui

Z-BoW

*/ aiuAir-re/t
/Z"Ops/V

4
/3"0P£/i'

PO"OPE^/

22 "^/"^/V

z^^apE/f

A/rjWiM/Pi- f//iiT ■^cA/VTj^/^Ai^ii'EA, /i/V<i4.o£j:>, ^ECo/ira /i^^DEff A/ £A£f^ i^AjE /Pa-^) Sotai /^JfE /y3>? 7/mEE^ ^.S F/M/iMEe

/T/^/^.

-?»<3

JTO

/(?a

Ci-^»p

OAK ^

i"/f.2".i

/o"/»-«"$

/2'/n.s1s

f//r£. z

/"//r£-i
/d'M-6-'S

Ci.efiT$-/Ci>y£Li) />?OOK//^Cir

(fAiv./au/^

(}/)i.l//IZt>A'

S-/2'ZaMi

/-/rf"

ft%c"

err.

<'3a"

CoAm/f/A- CocKP/r:

OaK
S"/1- t'S

— -

—

D£«ovi/ooei-fS^£<i)-AFr

Oak

7'a.

P/A-S.

PJJfE
JO

PmE

^-..^^^.y^ri-j^-^

4"6.

Py*K

OAK

8'^

PZ/fE

pyjTE

p»tr

/^ya"-''^'

/^•'mS"

m/i-si

OAK

^'TTfic/c

PtNE

MfLO PLdTS On Cock fir

F/A/£

Pz/fg

PyM£

pyy>'£

Oak

A^.s',.

3lv-/2"6

3'A'-/2"

/W^-2'S

P/A/£ ,

2y„W2lifS

ZW'3'

P/Mi:

^ou//CA r/6/v£^6^'^£

OAK
2'A"S

^-A-
3^"^

/fWO"

^'^■,y»

OAK
/i"A/2'

F£f^O£a- lOiV£/t

OAK

FAe£4vVe

dAK6''i~

fACES-iV/

- c/^P£/e

Oak- 3 ".t J'
/4 '//ia/y»

0ak8"'S",

^-5c ■%'■/-

Fcao/fi- £/v^/MS Xbo/tf

OAK-

/2"/>f- 2 'i

Oak

?£

r'Ai-/'/t"i

t/a.

OAtr

F«A/H£i- SPACWi a^

^"Cbhtbh

/2'Krnre/ii

OAJf- SAWN

/e" ^

/6'd

/SV

/a"^

/5V

- S/P£P

i ^J,^

/^■'

^^'«

i'A-

Oae/Si.£

OouBue

opciai£

Zli,"

2^"

/a'

£rvif/fv£ ^o»^

" -/7^LD£o^rV£eK

J'A'

Z^^'

e^'

' - £ic>£e>

y/t"

//2

Z'A"

i>p</aif

Pat/SJ-E

Z^'

Zfi'

i-i

//^Hoi-Pi-

/^"

Z^'

<^4"

/o"

^AKBOAtP Vj^fJXi

Oak

Pz/fi:.
3"/V-/Z-'i

Z- P//f£

s'i'Zi"

P//rj£ - 2.
3AK/0

/^//r/!-3

p/J?e

P/&£.

p//t^e
8'P>-£'i

— -

P//rs

P/'V£

P//r£

P//fe

C^^Wtf/W^ PiAf/K

—

/f/tWS£K,i - Tow/^a

3"^A/r/iA

^"/V/tiriL'i

3i'»P"r

6"/fAJr/ui

g"A>A/rii.A

» - Afopje//^^

S9Pr

s'/Vif/r/iy)

3 "/v/tirrt^

/So P^

J'AfA/V/LA

zoo'

^"/fa/r/LA

^OKA/TiMBE/f

^'^^>,

/2"y>t-(,'s

OAK „
/O'aZo"

/ay/Z"

/Z'yfi"

y*"5

Py/f£.

6''/H-Z"s

P/j^e

PZA/r

3 'kS "

3^A'yS"

^/v" s

//is

/y'/>i-z'6

Z^'

-S^v^"

3'*S'

j/i.-'-^S'

A>pr/^u/s F. J'/inf/Aaft-

ZTS/^.

/ao

ZC^ec

S"/»-S"^

(^K-P/>fe

/0'/1-g'i

OAK-pyff£

/Z-Ar'/f'S

Oak-
/2y>i-/2"J

" -F/iLAf^jMae)

Ml'

0»K

OAK _

2'm. e£

OAK

2"At-S"6

'4'M-/2i

/f/setso/zs- G/A(i£

TWO -P>V£

■^"yv-6"s

Ai"xb"

4 '^6'

B"x6"

8"xS'

" - C£f^r£fs

OAK

f/^/£

/'//y£

6"/>t-/a"£

P/n>e
/a"M.S"£

PA>E

P/Jr£
/2"Af.//l''s

7'/A'£

•> - £//q///e

Oak

0/)K ,

P//m
/o "/>i-/e 'i

P'/rS

P/Ar£
/2'ir/O'

P/aS-
/Z'xyz"

•' - i/peC^i/sro^

/^''Al-^-'i

p/Jre

^A/l-iBc/H^/t/SK

Oak- ^

M-^"^

OAK

O/lie

S''AI-/2*3

J?//ytJio<f

^/i/£

/a"M-/s'6

/Z'/*7

/2"Al

aA/< „
/2"/^-/&S

^VOO£K-A/?£A Sq. ^.

/3/9i./t/vcee>

2-f

^S-

SJr

'• - Posr

OiaK

d"AI-(,"i

OAK

/2'PI-/a'i

JB/ZASi-ir

3f- Jr.

Oak

Oak- ^^

OAk

» - Stock

3fe- ar

Oak- 7'P'A
METAi-2'A"

3ak-S''/>-
MerM-3V.

■ 8"^'A

OAK
9*6

/0''6

0 - Pii97£-:f///flE,

3jf/.'TM/CK

J>^"77f^cK

SK- STT

Ss-ir-

3/4f ' Thick

SKJT
r/A"WCK

//b'

Z^."

S/^Afrrloct

OAK

IPAK-

d/>K „

OAK

(MT-t
/l'/V-8"i

OAk-2

J/^£'9r/f/y6-'^MA£>t

P//r£

P^M£ •

P/^£^

P/Air

P/z/S

Haute OK

ffAf£

Va-TAH

P/^£

p/y£

P/aQT

Ctr^i'arPiQMT

Coffee
/6 az..

/Saz..

<iAL /jee/n'

*/0dAli(f£

>Vg

'°JSk^£

P/a'jS

S^eoiPt-^vK

Oak

^^K

//i,'ii.

OAK'f/K,

f Oak

^/y£-3.
s>y»'3fis

^/A'£3

^H^LP

a-J^z/y-A

z-F'/yB.

Z- X'/AT^

2-P//f£

J P/fJE

i-F^£
6'x6"

3P/y^

/'//r/£

P//<1S

^//^E

r/tf-4'i

p/jra.

/'y/^e

6T^rrc^.^s.%'>^^^J^rf.'^

■Z-*3' '

4"^ 4'

6'^ 6"

P//ire
/o'/c/a'

■

P//r£

6'x6"

/O'x/6'

• House OeTbuy^K

/>/f/£
2'* I'

i'/x*!'/!'

IpU'

^/A'£

ZlixA

,PyJM

ST£/»'

OAk-

OAT

OAK

7"i

(Oak

9z''^^8'^6

/2'J>>-91s

/■z'/v-zai

3a^

^T£/>tJ[?^/ro.

ir££i-

'irsief/T'asr.

pr.

Oak

6 "' ?-^'^

a/,K

Oak

dAK

OAK
/Z '^-/*i'i

9x,K

Oak- ^

2 -ays'

^T^/A/&£KS- J/JPS

— .

TTvO- 7='//v-iE

Tn/a-Fivte

P/A'£ 3

77/tV/9^T3-

//^1>f-/aV&

'7Jb/9/vsaM /^A/ec.

OAK
4'g

OAK

" - /^Ip^^/'/K

a /IK

10 /IK

3"x3'

Oak

P/y^e

P//t'£
£"A6-

e"KS-

" - ^<*A'r/A(f

P/MB-Cee/m

y*VyVTS

V/^£
Z'

P//r£

2'yi"

2%"

P/Af£

P/A>£

y^^0^-/<^/f

in n

APPENDIX II

Designs and Details
Typical Power Workboats

u u II u n u li II I I II r

n3
C

•OX)

-Ttf? C^rf AJiSydUQ r3fU

102

a ii

Q -1
< >.»

OS s'S
op

^ *^ a!

■<; -c 2

Oil
o ^

1 £ S
O S

1^ Ca 3

103

:i
a

u
J)

-C
U

0
0

104

Tf^

'^' O

JI^ JS

pii

r.-3

>-J

?ia

c.-

•^ .

S tn

"vs

? ^

»— t

o3 OJ

()

105

106

1
•g

•a

I
I

<
1-1
a.

H
Z
u

M
O
Z

OS
05
<

Q
Z

■<

tn ■g

Z S-s;
►J 8-=

i's^-

ililllllililmi?

107

0
I

S
o

o
z

2 !^

< -

0. ."=

W s

a E

108

H
U

Z
<

z
<

<
>

M
►J
M

0..2

1 =

109

CO
05

• 1—1

-♦->

0
0

t, o

^^s

cczq

®=:S

^^::^*'

'DO

110

tn "

in =

> "-

>■ 1

« •?

U s

a "

< s

u %

z g

O s

d. °

111

05
O

a
H

• fH

112

Power Towboat for Harbor Work

Length over all, 73 feet

Beam, 18 feet 4 inches

Draft, 8 feet

Power, 250 horsepower oil engine

Propeller, 6 feet 6 inches

An oil-burning engine of 250-liorsepower turns a 63^^ foot propeller

^ I ""HE accompanying plans are those of a power towboat
^ designed by R. E. Winslow, of Bristol, R. I. She
is 73 feet over all, 18 feet 4 inches beam and 8 feet
loaded draft. The follows the general design of the
smaller type of steam harbor towboats, but has many
interesting features and by using a gas engine running
on iow cost fuel she will be able to handle tows that
would not pay a big steam tug to handle, as well as
saving money owing to the smaller crew and no fuel
expense except when under way.

She is designed to handle any ordinary work in a har-
bor such as a 20 per cent larger steam tug would be
required to do, and can go in shoaler water than a steam
tug of similar power. She would be especially adapted
to canal towing and river work and still is seaworthy
enough to do sound and coastwise work. Her freeboard
to deck at bow is 6 feet 10 inches and least 2 feet 11
inches; at stern 3 feet S inches; so she will be quite
seaworthy and still not high enough out of water to
save unnecessary windage.

113

FOURTEEN DAY USE

RETURN TO DESK FROM WHICH BORROWED

„. /fGINEERING LIBRARY

Ihis book IS due on the last date stamped below,' or

on the date to which renewed.

Renewed books are subjea to immediate recall.

LOAN

'JUN 2d m

LD 21-100m-2,'55
(8139822)476

General Library
University of California
Berkeley ^m

YF 00372

46i;333

UNIVERSITY OF CALIFORNIA LIBRARY

Internet Archive Audio

Featured

Top

Images

Featured

Top

Software

Featured

Top

Books

Featured

Top

Video

Featured

Top

Mobile Apps

Browser Extensions

Archive-It Subscription

Save Page Now

Full text of "The design and construction of power workboats"

See other formats