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HANDBOOK OF SHIP CALCULATIONS, 
CONSTRUCTION AND OPERATION 



A BOOK OF REFERENCE FOR SHIPOWNERS, SHIP 
OFFICERS, SHIP AND ENGINE DRAUGHTSMEN. 
MARINE ENGINEERS, AND OTHERS ENGAGED 
IN THE BUILDING AND OPERATING OF SHIPS 



r 



BY 

CHARLES H. HUGHES 

NAVAL ARCHITECT AND ENGINEER 




D. APPLETON AND COMPANY 

NEW YORK LONDON 

1917 

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COPTRIOHT, 1917, BT 

D. APPLETON AND COMPANY 



Printed in the United States of America 

Digitized 






PREFACE 



This handbook has been compiled with the purpose of 
assembling in a single publication in convenient form, practical 
data for everyday reference, for men engaged in the designing, 
building and operating of ships. Theoretical calculations have 
been purposely omitted. 

Shipowners and men in the offices of steamship companies will 
find particular interest in the sections on Loading and Stowing 
of Cargoes, Maintenance, Ship Chartering, and Marine Insurance. 

To men employed in shipyards the sections on Ship Calcula- 
tions and Hull Construction, Structural Details, Machinery, 
and Ship Equipment, and the various formulae for making quick 
calculations will be of use. In making preliminary designs the 
section on Hull and Machinery Weights, as also the tables giving 
particulars of all classes of vessels, will be found convenient. 

Ship officers and marine engineers will find, in the section on 
Machinery, valuable data on the overhauling of boilers, on indi- 
cator cards, on the operating of pumps, condensers and motors, 
and many other practical subjects: They will find useful also 
the sections on Loading and Stowing of Cargoes, Ship Machinery, 
and many other subjects. 

Marine underwriters, ship brokers and freight brokers will find 
convenient data on ship construction and the stowage sizes of 
materials, with a large number of miscellaneous tables. 

For men engaged in the designing and building of war vessels 
a section on warships has been included, which describes . the 
different classes and their armor and armament. Although the 
fundamental calculations for all' vessels, merchant and war, are 
the same, the text contains frequent special references to war- 
ships, as on the subject of electric propulsion, electric steering 
gears, electric winches, etc. 

To the student of naval architecture and marine engineering 
this handbook offers a broadeF«onUfct«0i^ of practical data than 

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vi Preface 

any other published work. The very latest marine practice is given, 
and such subjects as electric propulsion, geared turbines, Diesel 
engines, and oil fuel are fully treated, as are also recent and special 
types of construction, such as tankers, battle cruisers, submarine 
chasers, and submarines. 

The handbook represents many years of collection and classifica- 
tion of material, assembled primarily for the writer's everyday use. 
The data have been obtained from many sources (see authorities), 
not only from textbooks but very largely from technical papers and 
trade literature. As it is impossible to mention in the text all the 
works consulted and used, the writer wishes to make here a general 
acknowledgment of his indebtedness to many other workers in the 
marine field. He wishes to thank particularly the editors of Inter- 
national Marine Engineering and Shipping Illustrated. Prof. H. E. 
Everett kindly revised the section on Freeboard. Mr. J. C. Craven 
checked Structural Details, while other friends in the trade read over 
various sections: To Mr. F. G. Wickware, of D. Appleton and Co., 
he is indebted for the typographical arrangement and many sugges- 
tions. 

Chas. H. Hughes. 
New York, 

June 26, 1917. 



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CONTENTS 

(See also Index) 



SECTION I 
WEIGHTS, MEASURES AND FORMULA 

PAGB 

Weights and Measures — United States and Great Britain 1 

Weights and Measures — Metric System 4 

Decimal Equivalents of Fractions of an Inch 5 

Centimeter, Gram, Second System 6 

Conversion Table — Metric Units into United States 7 

Board Measure .' 8 

Water, Weights of Different Units of 8 

Feet Board Measure in Timber 9 

Inches and Fractions in Decimals of a Foot 10 

Water Conversion Table 11 

Composition of Salt Water 12 

Specific Gravities and Weights of Materials 13 

Cubic Feet per Ton or Stowage Sines of Materials 16 

Shipping Weights of Lumber 18 

Weights of Miscellaneous Units of Different Products 19 

Bundling Schedule of Pipe 20 

Barrels, Sises of 20 

Horse Powers 22 

Equivalent Values of Mechanical and Electrical Units 23 

Comparison of Thermometer Scales 24 

Thermometers 25 

Circumferences and Areas of Circles Advancing by Eights 25 

Involution and Evolution 26 

To Extract the Square Root of a Number 26 

To Extract the Cube Root of a Number 27 

Logarithms 28 

Powers and Roots of Numbers 29 

Circumferences and Areas of Circles 29 

Geometrical Propositions 31 

Circle and Ellipse, Formula pertaining to 32 

Areas of Plane Figures and Surfaces of Solids 33 

Volumes of Solids 36 

Trigonometry— r-Trigonometric Functions 39 

Oblique Triangles 41 

Trigonometric Formula) 42 

Natural Sines, Cosines, etc., Table of 43 

Moment of Inertia, Radius of Gyration and Center of Gravity 50 

Center of Gravity of a Cross Section of a Ship 50 

Center of Gravity of a Water Plane 51 

Properties of Sections ^ f>2 



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SECTION II 
STRENGTH OF MATERIALS 

PAGO 

Definitions— Stress, Strain, Tension, etc 70 

Strength of Materials, Tables 71 

Factors of Safety 73 

Timber, Strength of 74 

Beams — Neutral Axes, Bending Moment, Shearing Stresses, etc 75 

Beam Formula 76 

Beams Under Various Loading Conditions 78 

Columns — Formulas for 84 

' Safe Loads for H and I Columns 86 

Safe Loads for Square and Round Wood Columns 87 

Safe Loads for Wrought Iron Pipe, Strong and Extra Strong Columns 88 

Torsional Stresses 89 

Springs 90 

Tubes, Pipes and Cylinders, Formulae for 90 

Bursting and Collapsing Pressures of Wrought Iron Tubes 91 

Ship Fittings, Strength of 91 

Shearing and Tensile Strength of Bolts 93 

Tests of Hooks. . .- -. 94 

Tests of Shackles 95 

Tests of Eye Bolts 95 

Tests of Hoist Hooks 96 

Tests of Turnbuckles 97 

Formula for Davits 97 

Stresses in Cranes, Derricks and Shear Legs 98 

Rivet Heads and Points 101 

Proportions of Rivets 102 

Diameters of 102 

Lengths for Ordering 102 

Signs for Rivets 103 

Shearing and Tensile Strength of Steel Rivets 104 

Formula) for Riveted Joints 105 

Shearing Value of Rivets and Bearing Value of Riveted Plates 107 

Reduction of Diameters to Inches 108 

Weight of Cone Head Rivets 109 

Number of Cone Head Rivets in 100 lbs 110 



SECTION III 

SHIPBUILDING MATERIALS 

Steel and Iron 

Steel, Methods of Manufacture Ill 

Carbon, Manganese, Nickel and Alloy Steels 112 

Structural Steel — Lloyd's, Am. Bureau of Shipping and Am. Soc. of Testing 

Materials, Requirements 114 

Rivet Steel , 117 

Cast Steel 118 



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Iron 119 

Wrought Iron . . 120 

Cart Iron 120 

Malleable Iron 121 

Pickling Steel Plates 121 

Galvanizing Fittings and Steel Plates 121 

Weights of Steel Plates in Hundredths of an Inch 122 

Standard Gauges— United States and Great Britain for Sheets and Plates ... 123 

Diamond Checkered Plates 125 

Weights of Sheets and Plates of Steel, Copper and Brass (Birmingham Wire 

Gauge) 126 

Weights of Sheets and Plates of Steel, Copper and Brass (American or Brown 

and Sharpe Gauge) 127 

Sises of Steel Plates and Heads 128 

Sizes and Properties of Structural Shapes 129 

Weights and Areas of Square and Round Bar/, and Circumferences of Round 

Bars 143 

Weights of Flat Rolled Steel Bars 149 

Non-Ferrous Metals and Alloys 

Copper 155 

Aluminum 155 

Zinc 155 

Lead 155 

Tin 155 

Bronses — Phosphor, Admiralty, Titan, Tobin, Manganese 156 

Gun Metal , 156 

Brasses 156 

Munts Metal 157 

Naval Brass 157 

Alloys 157 

Wood 

Sawing and Seasoning 157 

Hardness of Wood, How Measured 158 

Table of Relative Hardness of Soft Woods 158 

Table of Relative Hardness of Hard Woods 159 

Hard Wood Sizes 159 

Soft Wood Sizes 160 

Characteristics, Weights and Specific Gravities of Woods used in Ship- 
building 160 

Miscellaneous Non-Metallic Materials 

Oakum 162 

Caulking Cotton 162 

Portland Cement 162 

Insulating Materials — Magnesia, Asbestos, Cork, Hair Felt, Mineral Wool . . . 162 

Steam Pipe Covering 163 

Boiler Covering 163 



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Cylinder Covering 164 

Tests of Insulating Materials 164 

Relative Value of Non-Conducting Materials 165 

SECTION IV 
SHIP CALCULATIONS 

Lengths ,166 

Breadth 166 

Depth. 167 

Draft 167 

Displacement 168 

Displacement Curve 169 

Deadweight 169 

Registry 169 

Tonnage * ; 169 

Cubic Capacity 170 

Tons per Inch of Immersion 170 

Coefficients — Prismatic, Block, etc 171 

Wetted Surface. 172 

Center of Buoyancy 172 

Transverse Metacenter /. 173 

Metacentric Heights 174 

Moment of Inertia of a Water Plane about its Center Line 176 

Displacement Sheet 177 

Curves of Stability 183 

Notes on Stability 189 

Trim 190 

Moment to Alter Trim 190 

To Find the Trim by Trim Lines 192 

Quantity of Water That Will Flow Into a Ship Through a Hole in Her Side. . 195 

Compartment Flooded, Calculation of Trim, by Trim lines 195 

Compartment Flooded, Calculation of Trim, by Mean Sinkage 196 

Center of Gravity of a Vessel, Fore and Aft Position of 200 

Center of Gravity of a Vessel, Vertical Position of 202 

Heights of the Center of Gravity above the Base 202 

Heights of the Metacenter above the Base 202 

Effects of Moving Weights 203 

To Find the Center of Gravity of a Vessel by Moving Weights 204 

Freeboard 205 

Freeboard Calculations 213 

Freeboard Calculations for a Shelter Deck Steamer 218 

Freeboard Notes. 220 

Freeboard Markings 221 

Powering Vessels 222 

Approximate I. H. P. to Propel a Vessel 222 

Effective Horse Power 223 

Towing 223 

Engine Revolutions to Drive a Vessel at a Given Speed 224 

Formula for Estimating Speed of a Motor Boat 224 



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Resistance 225 

Law of Comparison 226 

Surface Friction Constants 227 

Launching 227 

Launching Ways 228 

Launching Calculations 229 

Releasing and Checking Devices 231 

Launching Data 232 

Declivity of Ways and Launching Velocity 233 



SECTION V 
HULL CONSTRUCTION 

Classification Societies and Organisations Governing Shipping 234 

Types of Merchant Vessels 238 

War Vessels 238 

Armor 244 

Armament 245 

Types of War Vessels 247 

Systems of Construction of Merchant Vessels. 253 

Frames 255 

Reverse Frames 256 

Shell Plating 258 

Double Bottom 261 

Keelsons and Longitudinals 263 

Keels. 264 

Deck Plating and Coverings 264 

Deck Beams I . . 265 

Hatchways 266 

Pillars 268 

Stringers 268 

Bulkheads 268 

Stem and Stern Frames 272 

Rudders 275 

Machinery Foundations 277 

Deck Erections 277 

Cementing 278 

Painting 279 

Wood Vessels 282 

Carpenter and Joiner Work 284 

Interior Painting 287 

Tables of Screws, Nails and Spikes 290 

Structural Strength 294 

Curve of Weights 294 

Curve of Buoyancy 296 

Curve of Loads 296 

Neutral Axis and Moment of Inertia Calculations 297 

Hogging and Sagging 298 

Curve of Shearing Stresses 298 

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Curve of Bending Moments 299 

Specification Headings for Hull 300 

Specification Headings for Machinery 301 

Specification Headings for Equipment 301 

Hull Weights, Formula for 302 

Hull Weights of Vessels 303 

Machinery Weights per I. h. p. 304 

Engine Weights 305 

Boiler Weights 306 

Weights of Water Tube Boilers 308 

Weights of Boilers, Engines and Auxiliaries 308 

Weights of Diesel Engines 309 

Data on Passenger and Cargo Steamers [reciprocating engines] 310, 311 

Data on Passenger and Cargo Steamers [turbines] 312 

Data on Excursion Vessels, Tugs, Lighters and Steam Yachts 314 

Data on Motor Ships 316 

Data on Motor Boats 317 

Data on Sailing Vessels with Motors 318 

Data on Schooners 319 

Data on Schooners with Motors 320 

Oil Carriers : 320 

Lumber Steamers 327 

Trawlers 327 

Dredges 327 

Shallow Draft Steamers 328 

Tunnel Vessels 330 

Fittings for Cattle and Horse Steamers 330 

Prices, Costs and Estimates 331 

Prices of Vessels sold in 1916 332 

Estimates for Building a Motor Schooner , 334 

Estimates for Operating a Motor Schooner 334 

Operating Costs of Diesel Engines 335 

Repair Costs of Motor Ships 336 

Costs of Electric and Refrigerating Systems 337 

Prices of Steam Engines and Boilers 337 

Estimates, Preparing 338 

Labor Costa 340 

SECTION VI 

MACHINERY 

Steam 

Definitions— British Thermal Unit, Mechanical Equivalent of Heat, Calorie.. 341 

Specific, Total and Latent Heat of Steam 342 

Saturated Steam 343 

Superheated Steam 343 

Dry Steam ' 343 

Wet Steam 343 

Steam Table— Properties of Saturated Steam ^Vf/^rvTv^ « • 344 

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Fuels 

Coal Required to Evaporate one Pound of Water 349 

Coal Consumption * 349 

Coal or Oil Consumptioon 350 

Evaporation per Pound of Combustible 350 

Heat Values of Coal 351 

Calorific Value of Coal from its Chemical Analysis 351 

Sises of Coals 351 

Heat Values of Wood 352 

Temperature of Fire 353 

Air Required for Combustion of Fuel . ., 353 

Oil 

Crude Petroleum and its Products 353 

Fuel Oil, Table of Beaum6 Gravity, Specific Gravity, etc., of. 354 

Beaum6 Gravity 355 

Specific Gravities and Weights of Oils 355 

Definitions — Flash Point, Fire Point, Viscosity, etc 356 

Oil for Boilers 356 

Heat Values of CHI 366 

Fuel Oils for Internal Combustion Engines 357 

Lubricating Oil 358 

Oil Burning Systems 360 

Boilers x 

Types of Boilers 363 

Scotch Boilers, Proportions of 363 

Scotch Boilers, Tables of 364 

Locomotive Boilers 366 

Leg Boilers 366 

Water Tube Boilers 368 

Comparison of Fire Tuoe and Water Tube Boilers 370 

Boiler Horse Power 371 

Boiler Horse Power Required for an Engine 371 

Factor of Evaporation 373 

Boiler Efficiency 374 

Gallons of Water Evaporated per Minute in Boilers 375 

Boiler Fittings . , 376 

Safety Valve < 376 

Stop Valve 377 

Feed Water Connections for Scotch Boilers 377 

Feed Check Valve 878 

Surface and Bottom Blows 378 

Steam Gauges 378 

Water Gauges and Cocks 379 

Boiler Circulators 379 

Fusible Plugs 379 

Injectors and Inspirators k 380 

Hydrometer 381 

Superheaters 382 

Aab Ejectors , 384 



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PAGE 

Boiler Operating 385 

Firing 385 

Shutting Off Boilers 386 

Overhauling Boilers ^ 386 

Boiling Out Boilers '. 387 

Draft 

Systems 389 

Measurement of Draft 389 

Velocity of Air under Pressure Escaping into the Atmosphere 390 

Air Required 390 

Blowers 391 

Forced Draft Installations 392 

Frictional Resistance of Stack 393 

Marine Steam Engines 

Types of 394 

Ratio of Cylinders and Steam Expansion 394 

Expansion, Cut-off and Back Pressure 395 

Crank Sequences 396 

Paddle Wheel Engines 397 

Valves 399 

Lap and Lead , 400 

Valve Travel 401 

Valve Mechanism 402 

Setting Valves 404 

Steam Pressure in a Cylinder at End of Stroke 404 

Steam Pressure at Different Cut-offs 405 

Cut-off and Coal or Steam Consumption 405 

Indicator Cards 406 

Mean Effective Pressure and I. H. P. Calculations 410 

Coal Consumption per I. H. P 411 

Engine Formulas— Estimated Horse Power 411 

Shafting 412 

Cylinders 413 

Connecting Rod 413 

Piston Rod 414 

Pistons 414 

Bearing Surfaces 414 

Engine Fittings 414 

.Thrust and Line Shafting Bearings 418 

Engine Room Floors 419 

Operating 419 

Trials. 421 

Propellers 

Definitions — Pitch, Driving Face, Projected Area, etc 424 

Slip 425 

Table of Propellers 426 

Formulae for Slip, Speed, Revolutions and Pitch 428 

Rule for Finding Pitch of a Propeller 428 



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Rule for Finding Helicoidal and Projected Area 420 

Propeller Thrust 429 

Propellers for Turbine Ships 429 

Formula for Keys, Nuts, etc 430 

Propellers for Motor Boats 431 

Weights of Propellers 432 

Speed Table, When Pitch, Slip and R. P.. M. Are Given 433 

Paddle Wheels 

Breadth of Floats, etc 436 

Formulas for Slip, Speed, Revolutions and Pitch 436 

Table of Paddle Wheels 437 

Steam Turbines 

Types of Turbines 439 

Geared Turbines 442 

Trials of Geared Turbines and Reciprocating Engines 443 

Turbo-electric Propulsion 444 

Comparative Performance of Different Systems of Propulsion 445 

Efficiency 446 

Steam Consumption 446- 

Weights 446 

Calculation of Horse Power 447 

Steam per Shaft Horse Power 448 

Auxiliaries 448 

Steam Plant Auxiliaries 

Definitions — Atmospheric Pressure, Gauge Pressure, etc 449 

Thermodynamics of Condensers 449 

Types of Condensers 450 

Surface Condensers 452 

Operating 453 

Vacuum and Vacuum Gauge 454 

To Find Vacuum under Working Conditions 455 

Vacuum and Corresponding Steam Temperature 456 

Jet Condensers 456 

Cooling Water Required for Surface or Jet Condenser 457 

Keel or Outboard Condensers 459 

Air Pump 459 

Circulating Pump , 462 

Feed and Filter Tank 462 

Steam Traps : 463 

Feed Water Filter 464 

Feed Water Heaters 465 

Evaporators . • 467 

Pumps, Types of 470 

Reciprocating Pumps 470 

Centrifugal Pumps 474 

Pumps installed in a Freight Steamer 477 

Installing and Operating Pumps 477 



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Internal Combustion Engines 

Fuels 478 

Operation 479 

Horse Power Formulas 480 

Table of Engines (Electric Ignition) 481 

Carburetors and Vaporizers 482 

Starting 482 

Reverse Gears 483 

Lubricating Systems 484 

Valves 484 

Ignition Systems 486 

Timers and Distributors 487 

Magnetos 489 

Spark Plugs 490 

Motor Trouble 491 

Hot Bulb Engines 492 

Diesel Engines 495 

Comparison of Diesel Engines, Steam Engines and Turbines 495 

General Features of Diesel Engines 496 

Operation 498 

Types of Diesel Engines 501 

Diesel Engine Installations 506 

Piping, Tubing, Valves and Fittings 

Trade Terms 507 

Tables of Standard, Extra Strong, and Double Extra Strong Wrought Iron 

Pipe 508, 509 

Boiler Tubes 510, 511, 512 

Copper Tubes 513 

Brass and Copper Tubes 514 

Brass and Copper Pipe 518 

Formula for Working Pressure 518 

Copper Tubes 519 

Bending Pipes and Tubes 519 

Flow of Water through Pipes 520 

Comparative Areas of Pipes 521 

Flanges 522 

Bolt and Pipe Threads 524 

Gaskets 526 

Nipples and Couplings 526 

Unions 526 

Materials for Piping Systems ,. 527 

Valves, Cocks and Fittings 528 

SECTION VII 

ELECTRICITY 

Definitions — Ohm, Ampere, Volt, Coulomb, etc 531 

Voltage 532 

Wires. Calculation of Size of 533 

Tables of Sizes of Wires 534,535, 536, 537 



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Diameters by Different Wire Gauges 538 

Wiring Systems ! 530 

Conduits 541 

Switchboards and Equipment 543 

Determination of Output 543 

Laying Out Electric Installations 544 

Wiring of a Steamer 547 

Wiring of a Motor Boat 550 

Wiring of Gasoline Engines 551 

Incandescent Lamps 552 

Searchlights 553 

Primary Batteries 554 

Storage Batteries 554 

Grouping of Cells 557 

Generating Sets 557 

Windings of Generators J 558 

Engine Horse Power 558 

Tables of Direct Connected Sets 559 

Operating Notes 560 

Electric Motors, Windings of 561 

Formula for Horse Power of Motor 562 

Weights of Motors. 563 

Current Taken by Motors 564 

Motors for Ship Work. 564 

Motor Starting and Controlling Devices 565 

SECTION VIII 

HEATING, VENTILATION, REFRIGERATION, DRAINAGE, PLUMBING 

AND FIRE EXTINGUISHING SYSTEMS 

Heat Passing Through a Ship's Side or Bulkhead 567 

Heating Systems 568 

Heating by Steam 568 

Steam Heating Installations 568 

Sizes of Radiators 560 

Square Feet of Radiation for a Room 570 

Heating Surfaces of Pipes 571 

Heating by Thermotanks 571 

Heating by Electricity 573 

Heating by Special Systems 574 

Ventilation 

Fresh Air Required. . » 675 

Air Pressure 576 

Systems — Plenum and Exhaust 576 

Ventilation of Oil Carriers 578 

Ventilation of Engine Rooms 579 

Ventilators 579 

Fans, Types of 580 

Horse Power Required to Drive a Fan 682 



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PAGB 

Ducts 582 

Data on the Escape of Air into the Atmosphere . . . . ? 583 

Duct Areas 584 

Laying Out Ventilating Systems 584 

Loss of Pressure by Friction of Air in Pipes 585 

Refrigeration 

Keeping Perishable Products 587 

Insulating Materials 587 

Cold Storage Temperatures 588 

Compression System 591 

Brine Circulating 593 

Refrigerants — Ammonia and Carbon Dioxide 594 

Different Makes of Machines 594 

Cooling by Air 595 

Pipe, Valves and Fittings 596 

Linear Feet of Pipe Required 596 

Capacity of Ammonia Compressors 597 

Refrigeration Required for Cold Storage Rooms 598 

Refrigeration Required for Stored Products 599 

Specific Heat and Latent Heat of Food Products 600 

Horse Power Required for Compressors . 60C 

Operating Notes 600 

Drainage 

Systems 601 

Main Drain 602 

Auxiliary Drain 603 

U. S. Steamboat-Inspection and Lloyd's Requirements 603 

Plumbing 

Fixtures 606 

Waste Lines 609 

Fresh Water Service 609 

Fire Extinguishing and Alarm Systems 

General Requirements 610 

Fire Main (Water) 611 

Sises of Water Streams 612 

Fire Main (Steam) 612 

Sulphur Dioxide System 613 

Sprinkler Systems 614 

Fire Alarms 614 

SECTION IX 

SHIP EQUIPMENT 

Steering Gears 615 

Steam Steering Gears 615 

Electric Steering Gears 616 

Arrangements 617 

Installations 618 



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Transmission 620 

Power Required to Turn a Rudder 623 

Pressure on Rudder 623 

Steering Chain and Rod 624 

Windlasses — Steam and Electric 624 

Table of Steam Windlasses 625 

Winches or Hoisting Engines — Steam and Electric 626 

Tables of Winches 627 

Power Required to Raise a Load 628 

Rope Capacity of a Drum 628 

Capstans and Gypsy Capstans) — Steam and Electric 630 

Tables of Capstans 630 

Towing Machines 631 

Rope, Trade Terms 632 

Hoisting Speeds 632 

Knots and Hitches , 633 

Tension in Hoisting Rope 634 

Kinds of Rope, Materials and Strands 634 

Weight and Strength of Manila Rope 636 

Weight and Strength of Hemp Clad Wire Rope 637 

Weight and Strength of Flattened Strand Hoisting Rope 638 

Table Comparing Manila and Hemp Clad Wire Rope 640 

How to Measure Wire Rope 640 

Weight and Strength of Cast Steel Wire Rope 641 

Weight and Strength of Steel Mooring Lines 642 

Formulse for Size and Weight of Rope 642 

Weight and Strength of Yacht Rigging and Guy Ropes 643 

Weight and Strength of Galvanized Steel Hawsers 644 

Weight and Strength of Galvanized Ships' Rigging and Guy Ropes 645 

Weight and Strength of Galvanized Steel Hawsers 646 

Length of Rope Required for Splices 646 

Blocks, Types of 646 

Wood Blocks for Manila Rope 648 

Steel Blocks for Wire Rope 648 

Working Loads for Blocks 648 

Tackles, Types of 650 

Power Gained with Tackles 652 

Chain 655 

Pitch, Breaking and Working Strains of Chain 656 

Anchors, Types of 657 

Anchors for Yachts and Motor Boats 657 

Anchors for Steam Vessels 658 

Anchors for Sailing Vessels 659 

Anchor Cranes 660 

Life-Saving Equipment — U. S. Steamboat-Inspection Requirements 663 

Life-Saving Equipment, Abstracts from Seamen's Bill 665 

Capacities of Lifeboats 669 

Lundin Lifeboats 670 

Engelhardt Collapsible Lifeboats 671 

Life Rafts : 672 



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Life Preservers 672 

Buoys 673 

Boats Carried by War Vessels •. , 673 

Boat Davits 673 

Rotating Davits 673 

Pivoted Davits 676 

Quadrant Davits 676 

Heel of a Vessel When Lowering a Boat 678 

Rigs of Vessels 679 

Wireless Equipment 680 

Storm Oil • 681 

Line-carrying Guns and Rockets 682 



SECTION X 

SHIP OPERATING 

Loading and Stowing of Cargoes 

General Considerations — Stability, Winging Out Weights, etc 683 

Oil Cargoes— Bulk 684 

Stowage of Oil in Barrels .-. . . 685 

Stowage of Oil in Cases 686 

Grain Cargoes 688 

Settling of Grain and Angle of Repose 688 

Rules of N. Y. Board of Underwriters 688 

Board of Trade Requirements 692 

Coal Cargoes 693 

Effect of Using Bunker Coal 693 

Rules of N. Y. Board of Underwriters 693 

Lumber Cargoes 694 

Regulations for Carrying Dangerous Articles 695 

MACHINERY OPERATING (see Index) 

Maintenance 

When Surveys Are to Be Made 696 

Hull — Shell Plating Working 698 

Decks Leaking 698 

Removing of Rubbish from Bilges 698 

Galvanic Action 698 

Corrosion in Double Bottom 699 

Sea Valves and Outboard Bearings 699 

Docking. .' 699 

Painting (see Index) 

Machinery, Care of 700 

Surveys 700 

Taking Indicator Cards 701 

Care of Boilers 701 

Log to Be Kept by Engineer 702 



Digitized 



by Google 



Table of Contents xxi 



PAOB 

; Ship Chartering 1 

Trip Charters .• 703 

Contracts for the Movement of Freight 704 

Time Charter 704 

Charter Forms 704 

Preamble Clause 707 

Delivery 707 

Redelivery 708 

Trading Limits and Insurance Warranties 708 

Speed amd Consumption -. 708 

Berth Terms 709 

Cotton Rates 709 

Abbreviations 709 

Marine Insurance 

Insurable Value 711 

Ship 711 

Freight. : 711 

Goods 711 

Policies, Paragraphs in ." 711 

Kinds of Policies. 713 

General Average 713 

Particular Average 714 

River Plate, Clause 715 

Protection and Indemnity Clause 715 

Collision or Running Down Clause 715 

Inchmaree Clause 715 

Export and Shipping Terms 

Abbreviations and Terms 716 

Authorities Quoted "*. 718 

Index 721 



Digiti 



zed by G00gk 



j 



ABBREVIATIONS AND SYMBOLS 



Weights and Measures (U. S. and English) 



oz. 


ounce 


lb. 


pound 
hundredweight 


cwt. 


in. 


inch 


// 


inch 


ft. 


foot 


/ 


foot 


yd. 


yard 
fathom 


fath. 


mi. 


mile 


kt. 


knot . 


pt. 


pint 


m. 


Weight! 
meter 


g. 


gram 



< 
> 

V 



a" 
a* 
a* 
a n 



% 

X 

log 
sin 
cos 
tan 
cotan 



qt 
gal. 

ft 

sq. 

D' 

cu. 

Ft. B.M 

C.G.S. 

bbl. 



quart 

gallon 

peck 

bushel 

square 

square foot 

cubic 

feet board measure 

Centimeter. Gram, 

Second System 
barrel 



Weights and Measures (Metric) 



equals 

less than 

more than 

sum 

square root of the 
quantity under the 
sign 

cube root of the quan- 
tity under the sign 

square root of a 

square of a 

nth root of a 

a raised to the nth 
power 



percent 

3.14159 

logarithm 

sine 

cosine 

tangent 

cotangent 



1. 


liter 


See metric system for prefixes. 


neous 
sec 


secant 


cosec 


cosecant 


F. or 




Fahr. 


Fahrenheit 


C 


Centigrade 


R 


Reaumer 


Be 


Beauine* 


I 


moment of inertia 


S 


modulus of section 


r 


radius of gyration 


Sp.gr. 


specific gravity 


g 


acceleration due to 




gravity = 32.16 ft. 




per sec. 


B.t.u. 


British thermal unit 


S.W.G. 


Stubs Wire Gauge 


B.w.g. 
B&S 


Birmingham wire gauge 


Brown & Sharpe 


A.W.G. 


American Wire Gauge 


I.W.G. 


Imperial Wire Gauge 


N.B.S. 


New British Standard 



xxm 



Digiti 



zed by G00gk 



XXIV 



ABBREVIATIONS AND SYMBOLS 



Naval Architecture 



F.P. 


forward perpendicular 
after perpendicular 


C.G. 


center of gravity 


A.P. 


B.M. 


distance between cen- 


Bet. 






ter of buoyancy and 


perps 


. length between perpen- 




metacenter 




diculars 


B.G. 


distance between cen- 


L.O.A. 


length over all 




ter of buoyancy and 


B. 


beam molded 




center of gravity 


D. 


depth molded 


G.M. 


distance between cen- 


** 


midship section 




ter of gravity and 


d.w. 


dead weight 




metacenter 


W.L. or 


G.Z. 


arm of righting couple 


w.L 


water line 


Bkhd. 


bulkhead 


C.B. 


center of buoyancy 


B.L. 


base line 


M. 


metacenter 


See Rivets and Riveting 




Machinery 




h.p. 


horsepower 


t.h.p. 


thrust horse power 


l.h.p. 


indicated horse power 


m.e.p. 


mean effective pres- 


e.h.p. 


effective horse power 




sure 


b.h.p. 


brake horse power 


r.p.m. 


revolutions per minute 


n.h.p. 


nominal horse power 


G.S. 


grate surface 
heating surface 


s.h.p. 


shaft horse power 


H.S. 




Electricity 




d.c. 


direct current 


Q. 


coulomb 


a.c. 


alternating current 


J. 


Joule 


C. 


amperes 


W. 


watt 


E. 


volts 


Kw. 


kilowatt 


R. 


Ohms 


c.p. 


candle power 


e.m.f. 


electromotive force 


cir. mils, circular mils 



Ship Chartering abbreviations. — See section on Ship Chartering. 

Marine Insurance abbreviations. — See section on Marine Insur- 
ance. 

Shipping and Export abbreviations. — See section on Shipping and 
Export Terms. 



Digiti 



zed by G00gk 



HANDBOOK OF SHIP CALCULATIONS, 
CONSTRUCTION AND OPERATION 



Digiti 



zed by G00gk 



Digiti 



zed by G00gk 



Handbook of 

Ship Calculations, Construction 

and Operation 

SECTION I 

WEIGHTS, MEASURES AND FORMULAE 

WEIGHTS AND MEASURES 

Troy Weight 
24 grains = 1 pennyweight 12 ounces = 1 pound 

20 pwts. = 1 ounce 
Used for weighing gold, silver and jewels. 

Apothecaries' Weight 
20 grains = 1 scruple 8 drams = 1 ounce 

3 scruples = 1 dram 12 ounces = 1 pound 

The ounce and pound in this are the same as in Troy weight. 

Avoirdupois Weight 
27.344 grains — 1 dram 2000 pounds — 1 short ton 

16 drams = 1 ounce 2240 pounds = 1 long ton 

16 ounces = 1 pound 

Shipping Weight 
16 ounces — 1 pound (lb.) 

28 pounds — 1 quarter (qr). 

4 quarters or 112 pounds — 1 hundredweight (cwt.) 
20 hundredweight or \ . , ^ x 

2240pounds J" " * ton ™ 

1 



2 WEIGHTS AND MEASURES 

•-*'■* Shipping Measure 
1 register ton = 100 cubic feet 

1 United States shipping ton = 40 cubic feet or o2.14 United States 

bushels or 31.16 Imperial bushels 
1 British shipping ton = 42 cubic feet or 32.72 Imperial 

bushels or 33.75 United States 

bushels 

Linear Measure (Land) 

12 inches = 1 foot 40 rods = 1 furlong 

3 feet = 1 yard 8 furlongs 1 , ., , . . . N 

5* yards = 1 rod or 5280 feetj = 1 nule (8tatute) 

Other units are: 4 inches = 1 hand; 9 inches = 1 span; 1000 
mils = 1 inch; 7.92 inches = 1 link: 100 links or 66 feet or 4 poles 
= 1 chain; 10 chains — 1 furlong. 

Mariner's Measure 

6 feet = 1 fathom 6080 feet ■» 1 nautical mile (knot) 

120 fathoms = 1 cable length 3 knots = 1 league 

1 cable length - 120 fathoms = 960 spans - 720 feet - 219.457 
meters. 

1 international nautical mile = -fa degree at meridian = .999326 
U. S. nautical miles = 1852 meters = 6076.10 ft. 

1 U. S. nautical mile is the length of one minute of arc of a great 
circle of a sphere whose surface equals that of the earth. Thus 
1 U. S. nautical mile » 1.15155 statute miles = 6080.20 ft. = 
1853.25 meters. 

1 British nautical mile = 1.15152 statute miles = 6080 feet = 
1853.19 meters. The knot generally adopted is the one of 6080 feet. 

Square Measure 
144 square inches = 1 square foot 40 square rods = 1 rood 

9 square feet = 1 square yard 4 roods = 1 acre 
30 J4 square yards = 1 square rod 640 acres = 1 square mile 

Time Measure 
60 seconds = 1 minute 24 hours — 1 day 

60 minutes — 1 hour 7 days = 1 week 

28, 29, 30 or 31 days - 1 calendar month (30 days = 1 month 
in computing interest) 
365 days * 1 year 366 days = 1 leap year 

Digitized by VJiOOQLC 



MEASURES 3 

Circular Measure 
60 seconds ~ 1 minute 90 degrees «= 1 quadrant 

60 minutes = 1 degree 360 degrees - 1 circumference 

Instead of an angle being given in degrees it can be given in 
radians, one radian being equal to the arc of a circle whose length 
is the radius. Thus if R denotes the radius, the circumference 

of the circle 2 w R, then the circular measure of 90° = — — W~~ ~ 

^; similarly the circular measure of 180° is r, 60° -£ , etc. 

An angle expressed in degrees may be reduced to circular measure 
by finding its ratio to 180° and multiplying the result by x. 

Hence the circular measure of 115° is — ^ — = .63 t 

An angle expressed in circular measure may be reduced to de- 
grees by multiplying by 180 and dividing by ir, or by substituting 

180 for x. As \£ = ~ X 180 - 84°. 
lo 15 

The angle whose subtending arc is equal to the radius, or the 

180° 
unit of circular measure reduced to degrees is = 57.2958. 

Therefore an angle expressed in circular measure may be reduced 

2 2 
to degrees by multiplying by 57.2958. Thus the angle - « ^ 

o o . 

X 57.2958 = 38.1972°. 



Dry Measure 
2 pints = 1 quart 4 pecks = 1 bushel 

8 quarts » 1 peck 36 bushels = 1 chaldron 

One United States struck bushel contains 2150.42 cu. ins. or 
1.244 cu. ft. By law its dimensions are those of a cylinder 18 }4 
ins. diameter by 8 ins. high. A heaped bushel is equal to 1 % struck . 
bushels the cone being 6 ins. high. A dry gallon contains 268.8 
cu. ins. and is H of a struck bushel. One U. S. struck bushel 
may be taken as approximately 1J£ cu. ft., or 1 cu. ft. as f of a 
busheL 

The British bushel contains 2218.19 cu. ins. or 1.2837 cu. ft. 
or 1.032 U. S. bushels. 



Digiti 



zed by G00gk 



4 WEIGHTS AND MEASURES 

Liquid Measure = 

4 gills = 1 pint 31H gallons — 1 barrel ~~ 

2 pints = 1 quart 2 barrels or 63 gallons = 

4 quarts = 1 gallon 1 hogshead 

One United States gallon contains 231 cu. ins. or .134 cu. ft., or ' 
1 cu. ft. contains 7.481 gallons. • 

The British Imperial gallon both liquid and dry contains v 277. 27 a 
cu. ins. or .160 cu. ft., and is equivalent to the volume of 10 lb. : 
of pure water at 62° F. To convert British to U. S. liquid gallons 
multiply by 1.2. To convert U. S. into British divide by 1.2. " 

Metric System 
The fundamental unit of the metric system is the meter, the 
unit of length, which is one ten-millionth of the distance from the 
pole to the equator or 39.3701 ins. From the meter the units of * 
capacity (liter) and of weight (gram) are derived with subdivisions ' 
of 10 or multiples of 10, the following prefixes being used: milli = , 

j^j, centi « ^, deci = ^, deca = 10, hecto - 100, kilo = 

1000, myrie = 10000. Thus a millimeter is ^^r of a meter, and 

so on. The units of meter, liter and gram are simply related, as 
for all practical purposes 1 cubic decimeter = 1 liter and 1 liter of 
water weighs 1 kilogram at 4° C. 

The metric system is specified by law in Argentina, Austria, 
Belgium, Bolivia, Brazil, Bulgaria, Chile, Colombia, Denmark, 
Finland, France, Germany, Holland, Hungary, Italy, Luxemburg, 
Mexico, Montenegro, Norway, Peru, Portugal, Roumania, Servia, 
Siam, Spain, Sweden, Turkey and Uruguay. 

Linear Measure 

10 millimeters = 1 centimeter = .394 inches 

10 centimeters = 1 decimeter «= 3.937 inches 

10 decimeters = 1 meter =* 39 37 inches or 3.281 feet 

10 meters = 1 decameter = 32.809 feet 

10 decameters = 1 hectometer = 328.09 feet 

10 hectometers = 1 kilometer = 3280.9 feet 



Surfaces 



surfaces 

100 square millimeters = 1 square centimeter = .155 square inches 
100 square centimeters = 1 square decimeter = 15.5 square inches 
100 square decimeters = 1 square meter — 10.764 square feet 



Digitized 



by vjOOQLC 



Decimal Equivalents op Fractions op an Inch, and Milli- 
meter-Inch Conversion Table 



Fract. 


Dec. 


Mm. 


Fract 


Dec. 


Mm. ||Mm. 


Dec. Inch 


Mm. 


Dec. Inch 


* ... 


.015625 


.397 


a 


.515625 


13.1 


1 
2 


.039370 
.078740 


51 
52 


2.007892" 
2.047262 


A.... 


.03125 


.79 


ii.... 


.53125 


13.49 


3 


.118110 


53 


2.086632 


A--- 


.046875 


1.19 


a.... 


.546875 


13.89 


4 
5 


.157480 
.196850 


54 

55 


2.126002 
2.165372 


A.... 


.0625 


1.59 


a.... 


.5625 


14.29 


6 


.236220 


56 


2.204742 


A .... 


.078125 


1.98 


ii.... 


.578125 


14.68 


7 
8 


.275509 
.314960 


57 
58 


2.244112 
2.283482 


A-... 


.09375 


2.38 


H-... 


.59375 


15.08 


9 


.354330 


59 


2.322852 


A--- 


.109375 


2.77 


«.... 


.609375 


15.48 


10 
11 


.393704 
.433074 


60 
61 


2.362226 
2.401596 


1.... 


.125 


3.17 


I.... 


.625 


15.87 


12 
13 


.472444 
.511814 


62 
63 


2.440966 
2.480336 


A-- 


.140625 


3.57 


ii-..- 


.640625 


16.27 


14 


.551184 


64 


2.519706 


A.-- 


.15625 


3.97 


H-... 


.65625 


16.7 


15 
16 


.590554 
.629924 


65 
66 


2.559076 
2.598446 


».... 


.171875 


4.37 


a.... 


.671875 


17.06 


17 


.669294 


67 


2.637816 


A.... 


.1875 


4.76 


«... . 


.6875 


17.46 


18 
19 


.708664 
.748034 


68 
69 


2.677186 
2.716566 


if...- 


.203125 


5.16 


a.... 


.703125 


17.86 


20 
21 


.787409 
.826779 


70 
71 


2.755930 
2.795300 


A-.-. 


.21875 


5.56 


Ii.... 


.71875 


18.26 


22 


.866149 


72 


2.834670 


if...- 


.234375 


5.95 


«.... 


.734375 


18.65 


23 
24 


.905519 
.944889 


73 
74 


2.874040 
2.913410 


*.... 


.25 


6.35 


!.... 


.75 


19.05 


25 


.984259 


75 


2.952780 


«.... 


.265625 


6.75 


a.... 


.765625 


19.45 


26 
27 


1.023629 
1.062999 


76 

77 


2.992150 
3.031520 


A--.- 


.28125 


7.14 


H.... 


.78125 


19.84 


28 


1.102369 


78 


3.070890 


«.... 


.296875 


7.54 


a.... 


.796875 


20.24 


29 
30 


1.141739 
1.181113 


79 
80 


3.110260 
3.149635 


A-.- 


.3125 


7.94 


ii... 


.8125 


20.64 


31 
32 


1.220483 
1.259853 


81 
82 


3.189005 
3.228375 


«-... 


.328125 


8.33 


a..-- 


.828125 


21.03 


33 


1.299223 


83 


3.267745 


«... 


.34375 


8.73 


ii.... 


.84375 


21.43 


34 
35 


1.338593 
1.377963 


84 
85 


3.307115 
3.306485 


u.... 


.359375 


9.13 


a..-. 


.859375 


21.83 


36 


1.417333 


86 


3.385855 


1.... 


.375 


9.52 


i.... 


.875 


22.22 


37 
38 


1.456703 
1.496073 


87 
88 


3.425225 
3.464595 


it.... 


.390625 


9.92 


a.... 


.890625 


22.62 


39 
40 


1.535443 
1.574817 


89 
90 


3.503965 
3.543339 


H-... 


.40625 


10.32 


ii.... 


.90625 


23.02 


41 


1.614187 


91 


3.582709 


11.... 


.421875 


10.72 


».... 


.921875 


23.41 


42 
43 


1.653557 
1.692927 


92 
93 


3.622079 
3.661449 


.7 


.4375 


11.11 


it... 


.9375 


23.81 


44 


1.732297 


94 


3.700819 


If...- 


.453125 


11.51 


a... 


.953125 


24.21 


45 
46 


1.771667 
1.811037 


95 
96 


3.740189 
3.779559 


M-... 


.46875 


11.91 


ii... 


.96875 


24.61 


47 


1.850407 


97 


3.818929 


H-... 


.484375 


12.30 


a.... 


.984375 


25. 


48 
49 


1.889777 
1.929147 


98 
99 


3.858299 
3.897669 


J.... 


.5 


12.7 


i 





25.4001 


50 


1.908522 


100 3.937043 



JvJ\Jvl^ 



WEIGHTS AND MEASURES 



Volume and Capacity 



.61 cubic inches 
6.10 cubic inches 
61.02 cubic inches 
.353 cubic feet 
3.53 cubic feet 
35.31 cubic feet 



10 milliliters = 1 centiliter 

10 centiliters = 1 deciliter 

10 deciliters = 1 liter 

10 liters = 1 decaliter 

10 decaliters = 1 hectoliter 

10 hectoliters = 1 kiloliter 

A liter is equal to the volume occupied by 1 cubic decimeter of 
water at 4° C. 

Weight 

10 milligrams = 1 centigram = .154 grains 

10 centigrams = 1 decigram = 1.54 grains 

10 decigrams = 1 gram = 15.43 grains 

10 grams = 1 decagram = 154.3 grains 

10 decagrams = 1 hectogram = .220 pound avoirdupois 

10 hectograms = 1 kilogram = 2.204 pound avoirdupois 

1000 kilograms = 1 metric ton = 2204.621 pound avoirdupois 
One gram is the weight of 1 cu. cm. of pure distilled water at a 

temperature of 39.2° F., or 4° C; a kilogram is the weight of 1 

liter (1 cubic decimeter) of water; a metric ton is the weight of 1 

cubic meter of water. 



Centimeter, Gram, Second, or Absolute System op Physical 
Measurement 

Unit of space or distance = 1 centimeter 
Unit of mass = 1 gram 

Unit of time = 1 second 



Unit of velocity = -? — 
Unit of acceleration 



= 1 centimeter in 1 second 



change of 1 unit of velocity 
in 1 second 
Acceleration due to gravity at Paris = 981 centimeters in 1 second. 



= 1 dyne! = ggj gramme 



.0022046 



981 



lb. = 



Unit of force 
.000002247 lb. 

A dyne is that force which acting on a mass of one gram during 

one second will give it a velocity of one centimeter per second. 

The weight of one gram in latitude 40° to 45° is about 980 dynes, 

at the equator 973 dynes and at the poles 984 dynes. Taking 

the value of g, the acceleration due to gravity in British measures 

at 32.185 ft. per second at Paris, and the meter as 39.37 ins., then 

32.185 X 12 nQ1 , 
1 gram = ^^ = 981 dynes. 



.3937 



Digiti 



zed by G00gk 



METRIC CONVERSION TABLE 



Metric Conversion Table 



Reading from Left to Right and Vice Versa 


Millimeters 




X 


.03937 


= 


Inches 


Millimeters 




=» 


25.400 


X 


Inches 


Meters 




X 


3.2809 


= 


Feet 


Meters 




= 


.3048 


.X 


Feet 


Kilometers 




X 


.621377 


= 


Miles 


Kilometers 




=a 


1.6093 


X 


Miles 


Square centimeters 


X 


.15500 


= 


Square inches 


Square centimeters 


= 


6.4515 


X 


Square inches 


Square meters 




X 


10.76410 


= 


Square feet 


Square meters 




= 


.09290 


X 


Square feet 


Square kilometers 


X 


247.1098 


» 


Acres 


Square kilometers 


= 


.00405 


X 


Acres 


Hectares 




X 


2.471 


= 


Acres 


Hectares 




=5 


.4047 


X 


Acres 


Cubic centimeters 


X 


.061025 


= 


Cubic inches 


Cubic centimeters 


= 


16.3866 


X 


Cubic inches 


Cubic meters 




X 


35.3156 


= 


Cubic feet 


Cubic meters 




= 


.02832 


X 


Cubic feet 


Cubic meters 




X 


1.308 


= 


Cubic yards 


Cubic meters 




= 


.765 


X 


Cubic yards 


Liters 




X 


61.023 . 


= 


Cubic inches 


Liters 




= 


.01639 


X 


Cubic inches 


Liters 




X 


.26418 


= 


U. S. Gallons 


Liters 




= 


3.7854 


X 


U. S. Gallons 


Grams 




X 


15.4324 


= 


Grains 


Grams , 




— 


.0648 


X 


Grains 


Grams 




X 


.03527 


= 


Ounces avoirdupois 


Grams 




— 


28.3495 


X 


Ounces avoirdupois 


Kilograms 




X 


2.2046 


= 


Pounds 


Kilograms 




= 


.4536 


X 


Pounds 


Kilog's per sq. 


centim. 


X 


14.2231 


= 


Lbs. per sq. inch 


Kilog's per sq. 


centim. 


= 


.0703 


X 


Lbs. per sq. inch 


Kilog's per cu. 


meter 


X 


.06243 


= 


Lbs. per cu. ft. 


Kilog's per cu. 


meter 


— 


16.01890 


X 


Lbs. per cu. ft. 


Metric tons (1000 Kg.) 


X 


1.1023 


= 


Tons (2000 lb.) 


Metric tons (1000 Kg.) 


= 


0.9072 


X 


Tons (2000 lb.) 


Kilowatts 




X 


1.3405 


= 


Horse power 


Kilowatts 




— 


.746 


X 


Horse power 


Calories 




X 


3.9683 


= 


B. thermal units 


Calories 




=» 


.2520 


X 


B. thermal units 


Example. 25.4 millimeters X . 


03937 = 1 inch. 


1 inch X 25.4 - 25.4 milli- 


meters. 










Digitized by VjiOOQIC 



8 WEIGHTS AND MEASURES 

Unit of work - 1 erg » 1 dyne-centimeter » .00000007373 ft. lb. 
Unit of power = 1 watt — 10,000,000 ergs per second 
- .7373 ft. lb. per second 

■W-7i6 hp -- 00134h P- 

Centimeter, Gram, Second (CGS) unit of magnetism — the 
quantity which attracts' or repels an equal quantity at a distance of 
one centimeter with a force of one dyne. 

CGS unit of electric current = the current which, flowing 
through a length of one centimeter of wire, acts with a force of 
one dyne upon a unit of magnetism distant one centimeter from 
every point of the wire. The ampere, the commercial unit of 
current, is one-tenth of the CGS unit. 

Board Measure 
To find the number of feet board measure in a stick of timber, 
multiply the length in feet, by the breadth in feet, by the thickness 
in inches. 

Example. Find the board measure of a piece of timber 20 ft. long, 2 ft. wide by 
2 ina. thick. 

20 ft. X 2 ft. X 2 ins. - 80 feet board measure. 

To convert board feet into cubic feet, divide the board feet by 12. 

To convert board feet into tons, divide the board feet by 12, 
and multiply the quotient by the weight of the timber per cubic 
foot, thus giving the weight in pounds. Divide the weight in 
pounds by 2240 to get it into long or shipping tons, or by 2000 to 
get into short tons. 

Example. A schooner has 1,000,000 feet board measure, of yellow pine on 
board. What is the weight of her load in shipping tons? 

1,000,000 «, 83t3 33 cu- ft> Yellow pine weighs 38 lb. per cu. ft. 
12 38 



3,166,654 lb. = 1415 tons nearly. 



Water 



One cubic foot of fresh water weighs 62.42 lb. at its maximum density 

39.1° F. 
One cubic foot of salt water weighs 64 lb. 
35.88 cubic feet of fresh water weighs one ton (2240 lb.) 
35 cubic feet of salt water weighs one ton 
One cubic foot of water (fresh or salt) = 7.48 gallons (U. S.) 
One gallon (U. S.) of fresh water weighs 8.33 lb. 
One gallon (U. S.) of salt water weighs 8.58 lb. 
One cubic foot of ice (fresh) weighs 56 lbs., specific gravity .9. 



ioogle 



BOARD MEASURE 



Feet Board Measure in Different Sizes of Timber* 



Siae in Inches 



Length in Feet 



10 12 14 



16 



18 20 22 24 26 28 



30 32 



2x4. 
2x6. 
2x8. 
2 x 10. 
2 x 12. 
2 x 14. 

2 x 16. 
2*x 12. 
2*x 14. 
2*x 16. 
3x6. 
3x8. 

3 x 10. 
3 x 12. 
3 x 14. 
3 x 16. 
4x4. 
4x6. 
4 
4 
4 
4 



6 x 

6 x 

6 x 

6 x 

6 x 

6 x 

8 x 

8 x 

8 x 

8 x 
10 x 
10 x 
10 x 14. 
10 x 16. 
12 x 12. 
12 x 14. 
12 x 16. 
14 x 14. 
14 x 16. 



8. 
10. 
12. 
14. 

6. 

8. 
10. 
12. 
14. 
16. 

8. 
10. 
12. 
14. 
10. 
12. 



61 
10 
13* 
16| 
20 
23* 
26} 
25 
29* 
33* 
15 
20 
25 
30 
35 
40 
13* 
20 
26* 
33* 
40 
46* 
30 
40 
50 
60 
70 
80 
53* 
66* 
80 
03* 
83* 
100 
116* 
133* 
120 
140 
160 
163* 
186} 



8 

12 

16 

20 

24 

28 

32 

30 

35 

40 

18 

24 

30 

36 

42 

48 

16 

24 

32 

40 

48 

56 

36 

48 

60 

72 

84 

96 

64 

80 

96 

112 

100 

120 

140 

160 

144 

168 

192 

196 

224 



9* 
14 
18} 
23* 
28 
32} 
37* 
35 
40} 
46} 
21 
28 
35 
42 
49 
56 
18} 
28 
37* 
46} 
56 
65* 
42 
56 
70 
84 
98 
112 
74} 
93* 
112 
130} 
116} 
140 
163* 
186} 
168 
196 
224 
228} 
261* 



10} 
16 
21* 
26} 
32 
37* 
42} 
40 
46} 
53* 
24 
32 
40 
48 
56 
64 
21* 
32 
42} 
63* 
64 
74} 
48 
64 
80 
96 
12 
128 
85* 
106} 
128 
149* 
133* 
160 
186} 
213* 
192 
224 
256 
261* 
298} 



12 

18 

24 

30 

36 

42 

48 

45 

52* 

60 

27 

36 

45 

54 

63 

72 

24 

36 

48 

60 

72 

84 

54 

72 

90 

108 

126 

144 
96 

120 

144 

168 

150 

180 

210 

240 

216 

252 

288 

294 

336 



13* 
20 
26} 
33* 
40 
46} 
63* 
50 
68* 
66} 
30 
40 
50 
60 
70 
80 
26} 
40 
63* 
66} 
80 
93* 
60 
80 
100 
120 
140 
160 
106} 
133* 
160 
186} 
166} 
200 
233* 
266} 
240 
280 
320 
326} 
373* 



14} 

22 

29* 

36} 

44 

61* 

68} 

55 

64* 

73* 

33 

44 

55 

66 

77 



44 

58} 

73* 

88 

102} 

66 

88 

110 

132 

154 

176 

17* 

146} 

176 

205* 

183* 

220 

256} 

293* 

264 

308 

352 

359* 

410} 



16 

24 

32 

40 

48 

56 

64 

60 

70 

80 

36 

48 

60 

72 

84 

96 

32 

48 

64 

80 

96 

112 

72 

96 

120 

144 

168 

192 

128 

160 

192 

224 

200 

240 

280 

320 

288 

336 

384 

392 

448 



17* 
26 
34} 
43* 
52 
60} 
69* 
65 
751 
86} 
39 
62 
65 
78 
91 
104 
34} 
52 



86} 
104 
121* 

78 
104 
130 
156 
182 
208 
138} 
173* 
208 
242} 
216} 
260 
303* 
346} 
312 
364 
416 
424} 
485* 



18} 

28 

37* 

46} 

56 

65* 

74} 

70 

81} 

93* 

42 

56 

70 

84 



112 
37* 
56 
74} 
93* 
112 
130} 
84 
112 
140 
168 
196 
224 
149* 
186} 
224 
261* 
233* 
280 
326} 
373* 
336 
392 
448 
457* 
622} 



20 
30 
40 
50 
60 
70 
80 
75 
87* 

100 
45 
60 
75 
90 

105 

120 
40 
60 
80 

100 

120 

140 
90 

120 

150 

180 

210 

240 

160 

200 

240 

280 

250 

300 

350 

400 

360 

420 

480 

490 

560 



21* 

32 

42}. 

53* 

64 

74} 

85* 

80 

93* 
106} 

48 

64 

80 

96 
112 
128 

42} 

64 

85* 
106} 
128 
149* 
96 
128 
160 
192 
224 
256 
170} 
213* 
256 
298} 
266} 
320 
373* 
426} 
384 
448 
512 
522} 
597* 



Thus a stick of timber 2 ins. X 4 ins. X 12 ft. long contains 
8 ft. board measure. Board measure is often abbreviated B. M. 

* From Mechanical Engineer's Handbook. W. Kent. 

Digitized by VJiOOQLC 





Inches 


and Fractions 


in Decimals op 


a Foot 


Parts of 

Foot in 

Inches 

and 

Fractions 


Decimal 
of a 
Foot 


Parts of 

Foot in 

Inches 

and 

Fractions 


Decimal 
of a 
Foot 


Parts of 

Foot in 

Inches 

and 

Fractions 


Decimal 
of a 

Foot 


Parts of 

Foot in 

Inches 

and 

Fractions 


Decimal 
of a 
Foot 


A 


.00520 


3A 


.25520 


6A 


.50520 


9A 


.75520 


y% 


.01040 


3H 


.26040 


m 


.51040 


W% 


.76040 


A 


.01562 


3A 


.26562 


6A 


.51562 


9A 


.76562 


M 


.02080 


W* 


.27080 


6M 


.52080 


9H 


.77080 


A 


.02600 


3A 


.27600 


6A 


.52600 


9A 


.77600 


H 


.03125 


2K 


.28125 


*K 


.53125 


9K 


.78125 


A 


.03640 


3A 


.28650 


CA 


.53640 


9A 


.78650 


H 


.04170 


3H 


.29170 


QH 


.54170 


9H 


.79170 


A 


.04687 


3A 


.29687 


6A 


.54687 


9A 


.79687 


% 


.05210 


W% 


.30210 


&A 


.55210 


w% 


.80210 


tt 


.05730 


3H 


.30730 


6tt 


.55730 


9H 


.80730 


& 


.06250 


3M 


.31250 


6M 


.56250 


9H 


.81250 


tt 


.06770 


3tf 


.31770 


6H 


.56770 


9tt 


.81770 


7 A 


.07290 


3% 


.32290 


&/% 


.57290 


9 7 A 


.82290 


tt 


.07812 


3tf 


.32812 


6tf 


.57812 


9H 


.82812 


l 


.08330 


4 


.33333 


7 


.58330. 


10 


.83333 


1A 


.08850 


4A 


.33850 


7A 


.58850 


10 A 


.83850 


1H 


.09375 


4M 


.34375 


7H 


.59375 


ioh 


.84375 


1A 


.09900 


4A 


.34900 


7A 


.59900 


ioa 


.84900 


l« 


.10420 


4K 


.35420 


7H 


.60420 


10M 


.85420 


1A 


.10937 


4 A 


.35937 


7A 


.60937 


10 A 


.85937 


1H 


.11460 


*K 


.36460 


7H 


.61460 


10H 


.86460 


1A 


.11980 


4A 


.36980 


7A 


.61980 


10A 


.86980 


1H 


.12500 


4^ 


.37500 


7H 


.62500 


10H 


.87500 


1A 


. 13020 


4A 


.38020 


7A 


.63020 


ioa 


.88020 


1H 


. 13540 


*K 


.38540 


W% 


.63540 


10« 


.88540 


ltt 


. 14062 


4tt 


.39062 


7H 


.64062 


10 H 


.89062 


1M 


.14580 


4% 


.39580 


7H 


.64580 


ioh 


.89580 


ltt 


.15100 


4tt 


.40100 


7tt 


.65100 


10 tt 


.90100 


i« 


. 15625 


. 4K 


.40625 


7J* 


.65625 


10H 


.90625 


1H 


.16150 


4tt 


.41140 


7tt 


.66150 


10 » 


.91150 


2 


. 16670 


5 


.41670 


8 


.66670 


n 


.91670 


2A 


.17187 


5A 


.42187 


8A 


.67187 


HA 


.92187 


2H 


. 17710 


5y s 


.42710. 


8H 


.67710 


UH 


.92710 


2A 


. 18230 


5A 


.43230 


8A 


.68230 


HA 


.93230 


2tf 


.18750 


5M 


.43750 


8^ 


.68750 


HM 


.93750 


2A 


. 19270 


5A 


.44270 


8A 


.69270 


HA 


.94270 


2^ 


. 19790 


5% 


.44790 


W% 


.69790 


UK 


.94790 


2A 


.20312 


5A 


.45312 


8A 


.70312 


HA 


.95312 


2*4 


.20830 


5H 


.45830 


8J4 


.70830 


HH 


.95830 


2A 


.21350 


5A 


.46350 


8A 


.71350 


HA 


.96350 


2^ 


.21875 


5^ 


.46875 


8$* 


.71875 


UK 


.96875 


2tt 


.22400 


5tt 


.47400 


8tt 


.72400 


litt 


.97400 


2H 


.22920 


5« 


.47920 


SH 


.72920 


nx 


.97920 


2tt 


.23437 


5tt 


.48437 


8tt 


.73437 


litt 


.98437 


2Ji 


.23950 


w% 


.48960 


8^ 


.73960 


uy 8 


.98960 


2tt 


.24480 


5tt 


.49480 


8tt 


.74480 


ntt 


.99480 


3 


.25000 


6 


.50000 


9 


.75000 


12 


1.00000 



10 



Digitized by VJ^J^VLV^ 



FRESH WATER 



11 



Fresh Water 

One Imperial gallon" = 277.27 

One Imperial gallon = . 16 

One Imperial gallon ' = 10.00 

One Imperial gallon = 4 . 54 

One Imperial gallon = 1 . 20 

One U. S. gallon = 231 

One U. S. gallon = . 134 

One U. S. gallon = 8.33 

One U. S. gallon = .83 

One U. S. gallon = 3.8 

One pound of water = 27 . 74 

One pound oi water = . 083 

One pound of water = . 10 

One cwt. of water = 11.2 

One cwt. of water = 13 . 44 

One cwt. of water = 1 . 79 

One ton of water = 35 . 88 

One ton of water =223.60 

One ton of water = 268.38 

One ton of water = 1000 

One ton of water = 1 

One cubic inch of water = .036 

One cubic inch of water = .0036 

One cubic inch of water = .0043 

One cubic foot of water = .027 

One cubic foot of water ■» . 55 

One cubic foot of water • = 62 . 42 

One cubic foot of water = 6.23 

One cubic foot of water = 7 . 48 

One cubic foot of water = 28.31 

One cubic foot of water = .028 

One liter of water = .22 

One liter of water = . 264 

One liter of water = 61 

One liter of water *» .0354 

One cubic meter of water = 220 

One cubic meter of water' = 264 

One cubic meter of water = 1 . 308 

One cubic meter of water = 35 . 31 

One cubic meter of water = 61024 

One cubic meter of water =* 1000 

One cubic meter of water = 1 

One cubic meter of water = 1000 

One Pood = 3.6 

One Eimer . =2.7 

OneVedros = 2.7 

One Miners' inch of water = 10 

One column of water 1 foot high = . 434 

One column of water 1 meter high = 1 . 43 

A pressure of 1 lb. per square inch = 2.31 
In the above, one ton = 2,240 lb. 



Cubic inches 

Cubic feet 

Lb. 

Liters 

U. S. gallons 

Cubic inches 

Cubic feet 

Lb. 

Imperial gallons 

Liters 

Cubic inches 

U. S. gallons 

Imperial gallons 

Imperial gallons 

U. S. gallons 

Cubic feet 

Cubic feet 

Imperial gallons 

U. S. gallons 

Liters (approx.) 

Cubic meter (approx.) 

Lb. 

Imperial gallons 

U. S. gallons 

Ton 

Cwt. 

Lb. 

Imperial gallons 

U. S. gallons 

Liters 

Cubic meters 

Imperial gallons 

U. S. gallons 

Cubic inches 

Cubic feet 

Imperial gallons 

U. S. gallons 

Cubic yards 

Cubic feet 

Cubic inches 

Kilos 

Ton (approx.) 

Liters 

Imperial gallons 

Imperial gallons 

Imperial gallons 

Imperial gals, (approx.) 

lib. pressure per sq. in. 

Lb. pressure per sq. in. 

Feet of water in height 



Digitized 



by Google 



12 



WEIGHTS AND MEASURES 



Weight and Size 


op Different Standard Gallons of Fresh 
Water 




Cubic " 
Inches in 
a Gallon 


Weight of 
a Gallon 
in Pounds 


Gallons 

in a Cubic 

Foot 


Weight of a cubic 
foot of fresh water, 
English standard, 
62 .321 lb. avoirdupois. 


Imperial or English . . . 
United Statea 


277.274 
231. 


10.00 
8.33111 


6.232102 
7.480519 



Salt Water 
The composition of salt water varies at different parts of the 
world, but usually contains the following to every 100 parts: 

Pure water 96.2 Sulphate of lime 08 

Common salt 2 . 71 Sulphate of magnesium ... .12 

Magnesium chloride 54 Calcium bicarbonate 01 

Magnesium bromide 01 Organic matter 33 

About 5 ounces of solid matter are present in one gallon of salt 
water, and this density can be expressed as a fraction thus 

solid matter __ 5 oz. __ 5 oz. __ 1_ 

water holding it in solution ~ lgal. "" 16 X 10 ~" 32 
that is, one part in 32 of sea water is solid matter, if an Eng- 
lish gallon of 10 lb. is used. If an American of 1 gal. = 8.33 lb., 
5 oz. 1 

"26.7 



then 



16 X 8.33 

Salt water boils at a higher temperature than fresh owing to its 
greater density, as the boiling point of water is increased by any 
substance that enters into combination with it. The property 
water has of holding chemical substances, as salts of lime in solu- 
tion, decreases as the temperature increases; from this follows that 
boilers carrying a high steam pressure form more scale than those 
working at lower temperatures and pressures. 

Water is at its maximum density at 39.1° F. or 4° C. The boil- 
ing point of fresh water at sea level is 212° F. and of salt water 
213.2. Fresh water freezes at 32° F. or 0° C; salt water freezes 
at a lower temperature. In freezing, water expands. Thus as 
hot water cools down from the boiling point it contracts to 39.1°, 
its maximum density, while below this temperature it expands again. 

The British and United States standard temperature for specific 
gravity is pure water at 62° F. Water has the greatest specific 
heat of any known substance except hydrogen, and is taken as 
the standard for all solids and liquids. 



Digiti 



zed by G00gk 



Specific Gravities and Weights op Materials* 



Material . 



Alcohol, 100%. 
Alum. 



Aluminum, bronze 

Aluminum, cast 

Aluminum, sheet 

Anthracite coal (broken) . 

Antimony 

Asbestos 

Ash, white-red 

Asphaltum 

Babbitt metal 

Barley 

Barytes 

Basalt 

Bauxite 

Beech 

Bell metal 

Benzine 

Birch 



Specific 
Gravity 1 



.79 



7.7 
2.55-2.75 



Bismuth 

Bituminous coal (broken) 

Boxwood 

Brass, cast-rolled 

Brick, common (1000 weigh about 3i tons) . 

Bronze, 7.9 to 14% tin 

Camphor 

Cedar, white-red 

Cement, Portland, loose 

Chalk 

Charcoal (piled) 

Cherry 

Chestnut 

Clay, dry 

Clay, moist 

Coal — see anthracite and bituminous. 
Coke 



Concrete, cement — stone — sand. 

Copper, cast, rolled 

Copper ore, pyrites 

Cork. 
Corn. 



Cotton, pressed 

Cypress 

Dolomite 

Earth, dry loose 

Earth, packed and moist. 

Ebony 

Elm.. 



1.4-1.7 

6.7 
2.1-2.8 
.62-. 65 
1.1-1.5 



4.5 

2.7-3.2 

2.55 



.73-. 75 



9.74 



.96 
8.4-8.7 
1.8-2.0 
7.4-8.9 



.32-. 38 
i.*8-2.'6* 



.70 
.66 



2.2-2.4 

8.8-9.0 

4.1-4.3 

.25 



1.25 
.72 



1.47-1.50 

.48 
2.9 



Weight, lb. 
per cu. ft. 



49 
107 
478 
160 
168 
47-58 
417 
153 

40 

81 
456 

38 
281 
184 
159 
' 44 
503 

46 

33 
608 

49 

63 
534 
120 
509 

62 

22 

90 

137 

10-14 

42 

41 

63 
110 

23-32 
144 
556 
262 

15.6 

48 

93 

30 
181 

76 

96 

79 

45 



1 The specific gravities of solids and liquids refer to water at 4° C. The weights 
per cubic foot are derived from average specific gravities. 
* From Pocket Companion. Carnegie Steel Co. 

1Q 



y Google 



Specific Gravities and Weights of Materials — Continued 



Material 



Specific 
Gravity 



Weight, lb. 
per cu. ft. 



Emery 

Felspar 

Fir, Douglas (Oregon pine) . 

Flagging 

Flax 

Flour, loose 

Flour, pressed 

Flint 

Gasoline 

Glass, common 

Glass, plate or crown 

Gold, cast, hammered 

Gneiss, serpentine 

Granite.- 

Graphite 

Greenheart 

Gypsum 

Hay and straw bales 

Hemlock 

Hickory 

Hornblende 

Ice 

India rubber 

Iron, cast, pig 

Iron, wrought 

Ivory 

Kerosene 

Lancewood 

Lead 

Lead, ore, galena 

Leather 

Lignum vita? 

Lime, quick, loose 

Limestone 

Linseed oil 

Locust '. 

Manganese 

Manganese ore . . . 

Mahogany, Honduras 

Mahogany, Spanish 

Maple 

Marble 

Mercury 

Mica 

Muntz metal 

Nickel 

Nitric acid 91% 

Oak, live „ 



2.5-2.6 
.51 



1.47-1.50 
.4-. 5 

.7-. 8 



.66-. 69 

2.4-2.6 

2.45-2.72 

19.25 

2.4 

2.5 

1.9-2.3 



2.3 



.42-. 52 
.74-. 84 

3. 
.88-. 92 



7.2 
7.6-7.9 



.66 



11.37 

7.3 

.86-1.02 

1.10 



2.5 



.73 

7.2-8.0 

3.7 



.65 
13.6 



8.9-9.2 
1.5 
.95 



251 
159 

32 
168 

93 

28 

47 
164 

42 
156 
161 
1205 
159 
175 
131 

62.5 
159 

20 

29 

49 
187 

56 

58 
450 
485 
114 

42 

42 
710 
465 

59 

83 

53-60 

165 

58 

46 
475 
259 

35 

53 

49 
170 
• 849 
183 
511 
565 

94 

59 



14 



Digitized by 



Google 



Specific Gravities and Weights of Materials — Continued 



Material 



Specific 
Gravity 



Weight, lb. 
per cu. ft. 



Oak, red, black 

Oats, bulk 

Oil — see gasoline, petroleum, etc. 

Olive oil 

Oregon pine 

Paper 

Petroleum, crude 

Petroleum, refined 

Phosphate rock 

Phosphor bronze 

Pine — long leaf yellow 

Pine — short leaf yellow 

Pine — white 

Pitch , 

Platinum, cast, hammered 

Plumbago 

Poplar 

Potatoes, piled 

Quartz, flint 

Rubber, caoutchouc 

Rubber goods 

Rye 

Salt, granulated, piled 

Saltpeter 

Sand, dry, loose ". 

Sand, wet 

Sandstone 

Shale, slate, piled 

Silver, cast, hammered 

Soapstone, talc 

Spruce, white, black 

Starch 

Steel, cast 

Steel, structural 

Sulphur 

Talc 

Tallow 

Tar, bituminous 

Teak 

Tin, cast, hammered 

Tin ore 

Walnut, black 

Water, fresh 

Water, salt 

Wheat 

White metal, Babbitt 

Wool, pressed 

Zinc, cast, rolled 

Zinc ore, blende 



.65 



..51 
.70 

.87 
.79 
3.2 



.70 

.6 

.41 

1.07 

21.1 



.48 



2.5 

.92 
1.-2. 



2.2 



10.4 
2.6 
.4 
1.53 



7.8 

1.93 

2.6 



.82 
7.2 
6.4r-7.0 

.61 
1. 
1.02 



1.32 

6.9 

3.9 



41 
32 

57 

32 

58 

54 

50 
200 
537 

44 

38 

26 

69 

1330 

140 

30 

42 
165 

59 

94 

48 

48 

67 

90-105 

120 

147 

92 
656 
169 

27 

96 

493 

. 490 

125 

169 

59 

75 

52 
459 
418 

38 

62. £ 

64 

48 
456 

82 
440 
253 



- 



15 



Cubic Feet per Ton (2240 Le.) op Different Materials* 



Material 


Cu. ft. 
per ton 


Material 


Cu. ft. 
per ton 


Alcohol in casks 


80 
70 
108 
120 
90 
52 
70 
50 
53 
17 
65 
90 
59 
47 
68 
47 
93 
125 
80 
54 
74 
45 
60 
85 
50 
50 
52 
85 
80 
110 
55 
80 
124 
155 
22 
65 
70 
50 
56 
43 
80 
184 
240 
40 
38 
70 
60 
80 


Cider in casks 


65 


Almonds in bags 


Cigars in cases 


180 


Almonds in hogsheads. . . 

Aniseed in bags 

Apples in boxes 


Cinchona (Peruvian bark) 

Cloth goods in cases 

Cloves in cases 


140 
87 
50 


Arrowroot in bags ...... 

Arrowroot in boxes 

Arrowroot in cases 

Asbestos in cases 


Coal (Admiralty) 

Coal (American) 

Coal (Newcastle) 

Coal (Welsh) 


48 

.43 

45 

40 


Asphalt 


Cocoa in bags 


80 


Bacon in cases 


Cocoanuts in bulk 

Coffee in bags 


140 


Bananas 


61 


Barley in bags 


Coir yarn in bales 

Coke 


190 


Barley in bulk 


80 


Beans, haricot, in bags. . 
Beans in bulk 


Copper, cast 


10 


Copper ore 


10-20 


Beef, frozen, packed 

Beef hung in quarters. . . 
Beer, bottled, in cases. . . 


Copper sulphate in casks 

Copperas in casks 

Copra in cases 


50 
52 
85 


Beer in hogsheads 

Beeswax 


Cork wood in bales 

Cotton — a bale of U. S. 
cotton is 54 ins. by 27 by 
24 to 30 ins. high de- 
pending on the com- 
pression, assuming 30 
ins. space occupied is 
25.3 cu. ft. Average 
stowage per ton 

Cotton waste 


270 


Bone meal 




Bones, crushed 




Bones, loose 




Books 




Borate of lime 




Borax in cases 




Bottles, empty, in crates 
Bran compressed in bales 
Bran in bags 


114 
170 


Cowrie shells in bags 

Creosote in casks 

Dates 


75 


Brandy, bottled, in cases 

Brandy in casks 

Bread in bulk 


60 
43 


Earth, loose 


25 


Bread in cases 

Bricks 


Earthenware in crates. . . 
Fish in boxes 


47 
95 


Buckwheat in bags 

Butter in kegs or cases. . 

Camphor in cases 

Candles in boxes 

Canvas in bales 

Carpets in rolls 

Cassia in cases 


Fish, frozen 


60 


Flax 


105 


Flour in bags 


47 


Flour in barrels 

Freestone 

Fuel oil 


60 

16 

39-40 


Furs in cases 


130" 


Cellulose 


Ginger 


80 


Cement in barrels 


Glass bottles 


85 


Chalk in barrels 

Cheese 


Glassware in crates 

Granite blocks 


180 
16 


Chicory in sacks 

Chloride of lime in casks 


Gravel, coarse 


23 


Grease 


65 









* From The Naval Constructor. 



G. Simpson. 

16 



y Google 



Cubic Peet per Ton (2240 Lb.) of Different Materials — Cont. 



Material 



Cu. ft. 
per ton 



Material 



Cu. ft. 
per ton 



Guano. . 

Gum 

Gunny bags 

Gunpowder 

Hair, pressed 

Ham in barrels 

Hay, compressed 

Hay, uncompressed . 

Hemp in bales . . 

Hemp seed in bags . . . 
Herrings in barrels . . . 
Herrings in boxes .... 

Hides in bales 

Hides in barrels 

Hops in bales 

Ice 

India rubber, crude 

Indigo in cases 

Iron, corrugated sheets 

Iron, pig 

Ivory 

Jute 

Kaolin (China clay) in 

bags... 

Lard 

Lead, pig 

Lead pipes, random sizes 

about.. 

Leather in bales 

Leather in rolls 

Lemons 

Linseed in bags 

Locust beams in bulk. . . 

Logwood 

Manure — phosphate. . . . 

Maize in bags 

Maize in bulk 

Marble in slabs 

Margarine in tubs 

Marl 

Matches 

Melons 

Milk, condensed, in cases 

Millet in bags 

Mineral water in cases . 

Molasses in bulk 

Molasses in puncheons. 
Mutton 



42 

60 

50 

48 

160 

70 

120 

140 

100 

70 

60 

85 

120 

50 

260 

39 

72 

67 

36 

10 

28 

58 

40 
70 

8 

12 
90 

220 
85 
57 
84 
92 
45 
51 
49 
17 
69 
28 

120 
80 
45 
50 
70 
25 
65 

110 



Nails, kegs .... 
Nitrate of soda 
Nuts, Brazil, in barrels. 
Nuts, pistachio, in cases 

Oatmeal in sacks 

Oats in bags 

Oats in bulk 

Oil, lubricating, in bbls.. 
Oil in drums . . . 
Oil in bottles in 
Oil cake in bags.. 
, Olives in barrels.. 
Onions in boxes . . 
Oranges in boxes . 
Oysters in barrels 
Paint in drums. .. 
Paper in rolls .... 

Peas in bags 

Phosphate of lime 
Pineapples, canned, and 

in boxes 

Pitch in barrels . . . 
Potatoes in bags . . 
Potatoes in barrels 
Prunes in casks . . . 

Raisins 

Rape seed 

Rice in bags 

Rice meal 

Rope 

Rum in bottles and cases 
Rum in hogsheads 
Rye in bags 



Salt in bulk . . . 
Salt in barrels . 

Saltpeter 

Sand, fine 

Sand, coarse. . . 

Sandstone 

Shellac 

Silk in bales . . , 
Silk in cases . . 

Slate 

Soap in boxes. 
Soda in ba_ 
Soda in cask 
Sponge. 



17 



21 
32 
90 
70 
65 
78 
61 
60 
49 
75 
50 
67 
77 
90 
60 
16 
120 
50 
42 

60 
45 
55 
68 
52 
52 
60 
48 
62 

135 
66 
70 
53 
55 
37 
52 
36 
19 
20 
14 
83 

125 

112 
13 
46 
57 
54 

152 



Cubic Feet per Ton (2240 Lb), of Different Materials — Cont. 



Material 



Cu. ft. 
per ton 



Material 



Cu. ft. 
per ton 



Starch in cases ... 

Stone, paving 

Stone, limestone 

Sugar in bags 

Sugar in hogsheads . . . 

Sugar in casks 

Sulphur in bulk 

Sulphur ip cases 

Sulphur in kegs 

Sumac in bags ..." 

Syrup 

Tallow in barrels and 

tierces 

Tallow in hogsheads. . 
Tamarinds in cases . . . 
Tamarinds in casks or 

kegs 

Tan extract 

Tapioca 

Tar in barrels 

Tea, China, in chests . . . 
Tea, Indian, in cases. . . 
Ties, oak 



100 
50 
80 
15 
13 
40 
54 
60 
27 
40 
60 
70 
34 

58 
70 
45 

54 

48 

57 

54 

100 



Ties, steel 

Tiles, roofing, in crates. 
Tobacco, Brazilian, in 

bales 

Tobacco, Turkish, m 

small bales 

Turmeric 

Turpentine in barrels . 

Vermicelli 

Water, fresh 

Water, salt 

Wheat in bags . 

Wheat iit bulk 

Whitening in casks . . . 
Woods, sawn into planks 

Ash 

Beech 

Elm 

Fir 

Greenheart 

Mahogany 

Wool in sheets 

Wool in bales, pressed 



38 
85 

40 

150 
80 
60 

110 
36 
35 
52 
48 
39 

39 
51 
60 
65 
34 
34 
260 
100 



Shipping Weights of American Lumber ' 
(Rough Lumber in lb. per lfiOO ft. board measure) 



Ash, black 3,200 

Ash, white 3,500 

Basswood 2,500 

Beech 4,000 

Birch 4,000 

Butternut 2,500 

Cherry 3,800 

Chestnut 2,800 

Cottonwood 2,800 

Douglas fir 3,300 

Elm, rock 3,800 

Elm, soft 3,000 

Gum, red 3,300 



Gum, sap 

Hemlock 

Hickory 

Long leaf pine.. 
Mahogany .... 

Maple, soft 

Maple, hard. . . 

Oak 

Poplar, yellow. 
Shortleaf pine . 

Sycamore 

Tupelo 

Walnut 



3,000 
3,000 
4,500 
3,000 
3,500 
3,000 
3,900 
3,900 
2,800 
4,200 
3,000 
2,800 
4,000 



Weight of Green Logs per lfiOO ft. board measure 

Yellow pine (Southern) 8,000 to 10,000 lb. 

Norway pine (Michigan) 7,000 to 8,000 lb. 

Hemlock (Pennsylvania), bark off w ,.. .6,000 to 7,000 lb. 



18 



bigitizedby^ 



WEIGHTS 19 

Weights of Miscellaneous Units of Different Products 

Lb. 

Keg of nails 100 

Firkin of butter 56 

Chest of tea • 68 

Barrel of flour, etc. — See Sizes of Barrels. 

Bushel of oysters 80 

Bushel of clams 100 

Bushel of barley 48 

Bushel of beans 60 

Bushel of buckwheat 48 

Bushel of charcoal 30 

Bushel of castor beans 60 

Bushel of clover seed 60 

Bushel of corn (shelled) 56 

Bushel of corn (on cob) 70 

Bushel of malt 34 

Bushel of onions - 57 

Bushel of oats 32 

Bushel of potatoes 60 

Bushel of rye 56 

Bushel of Timothy seed 45 

Bushel of wheat 60 

Quarter or 8 bushels of wheat 480 

Gallon of molasses 12 

Bale of United States cotton weighs 500 

Bale of Peruvian cotton weighs 200 

Bale of Brazilian cotton weighs 250 

Bale of East Indian cotton weighs 400 

Bale of Egyptian cotton weighs t 750 

Bale of jute weighs 440 

One bushel of wheat = 60 lb. = 1.244 cu. ft. 

Eight bushels of wheat = one quarter = 9.952 cu. ft. = 480 lb. 

One ton of wheat = 4% quarters = 46.43 cu. ft. = 2240 lb. 

A case of kerosene oil generally contains two 5-gallon cans 
or ten 1-gallon, in the former taking up 2 cu. ft. and in the 
latter 2.1. Some hold fifteen 1-gallon cans and take up 3.2 
cu. ft. 

Gallon of honey 12 

Gallon of crude oil about -. 8J^ 

7 bags of sugar (one ton) 2240 

11 bags of potatoes (one ton) 2240 

One bag of flour 140 

Cord of dry hickory 4369 

Cord of dry maple 2862 

Linoleum M of an inch thick, including cement, weighs 1.5 lb. 
per sq. ft. 

Rubber tiling, & of an inch thick, weighs 2 lb. per sq. ft. 

White tiling, A of an inch thick, weighs 6 lb. per sq. ft. 

Digitized by VJiOOQLC 



1 



20 WEIGHTS AND MEASURES 

Bundling Schedule for Buttweld Pipe 1 
This schedule applies to buttweld wrought iron pipe only. 

Standard Weight Pipe 

Size "£i2Er A ° ?SS '£°' A orBuMTn ht 

per Bundle BundfT Lb. 

H • 42(Approx.)500 120 

H 24 450 190 

Vs 18 340 190 

Y 2 12 245 210 

% 7 140 160 

1 5 100 168 

IK 3 60 138 

l l A.... 3 58 158 



Extra Strong Pipe 

Vs 42 ^ 500 157 

H 24 450 241 

Vs 18 330 244 

}4 12 245 266 

H 7 140 206 

1 5 100 217 

\\i 3 60 180 

\y 2 3 58 211 



Double Extra Strong Pipe 

Y 2 7 126 215 

M 5 95 230 

1 3 60 220 

lli 3 60 310 

\y 2 3 60 380 

1 Adopted on June 1st, 1915, at the suggestion of the National Pipe and Supplies 
Association. 

Barrels 

There is no standard size of barrel universally adopted either 
by Great Britain or the United States. In Great Britain an old 
wine barrel = 26 M imperial gallons, an ale barrel = 31 J^ imperial 
gallons and a beer barrel = 36 J^ imperial gallons. A French 
barrique of Bordeaux = 228 liters = 50 imperial gallons. Four 
barriques = 1 tonneau. 

Digitized by LiOOQ IC 



BARRELS 



21 



A barrel for fruit, vegetables and other dry commodities as 
fixed by a United States statute approved March 4, 1914, specifies 
staves 28% ins. long, heads 17% ins. dia., distance between heads 
26 ins., circumference 64 ins., all outside measurements, repre- 
senting as nearly as possible 7050 cu. ins. or 4.08 cu. ft., equivalent 
to 105 dry quarts. Besides the above the different states specify 
the dimensions of barrels for various commodities. The usual 
barrel for liquids contains 31% U. S. wine gallons of 231 cu. ins. 
Below is a table of wood barrels. 



Material Held 



Diameter 

Top and 

Bottom 

(ins.) 



Diameter 

at 

Bilge 

(ins.) 



Height 
(ins.) 



Cubic Feet 



Sugar. . . 
Flour. . . , 
Oil 

Fish. . . . 
Meat . . . 
Molasses 

Salt.... 
Cement. 
Lime . . . 
Apple... 
Potato.. 
Tar 



19% 

17% 
21% 

20 
21% 
22 % 

18%, 

16 

16 

17% 

15 

19% 



21% 

19% 
25H 

22% 
25Ji 
27% 

21 
18 
18 

19 

21% 



30 

28% 
33 

30 
33 
35 

30 

28% 
28% 
28% 



30 



5.60 

4.36 

8.37 

52 gals. 

6.23 

8.37 

10.04 

60 gals. 

5.34 

3.75 

3.75 

4.33 

3.22 

5.60 



All dimensions are outside. 
Rieley, Cleveland, O. 



The above barrels are of wood, data from G. A. 



An oil company (Piatt & Washburn Refg Co., New York) gave 
the following figures on the sizes of their wood barrels and steel 
drums: 



Material 



Wood 

Wood half barrel 
Drum (steel) 
Half-drum 



Diam. 


Diam. 






Wt. with 


Top and 


at 


Length 


Capacity 


Oil 


Bottom 


Bilge 






About 


(ins.) 


(ins.) 


(ins.) 


(gals.) 


(lb.) 


21 


26 


33Jrf 


50 


450 


17 


22 


27 


28 


205 


22 


26 


34 


50 


450 


17 


22 


27 


28 


213 



Tare 
(lb.) 



73 
45 
50 

24 



y Google 



One horse power* 



22 WEIGHTS AND MEASURES 

Horse Powers 

Horse Power (h. p.), the unit of power equivalent to raising a 
weight of 33,000 lb. one foot in one minute. 

2.64 lb. of water evaporated per hour from 
and at 212° F. 
746 watts 
.746 kw. 
33,000 ft. lb. per minute 
550 ft. lb. per second 
2,545 heat units per hour 
42.4 heat units per minute 

Indicated Horse Power (i. h. p.) is the power as measured by 
an indicator and calculated by the following formula: 

P = mean effective pressure in pounds per sq. in. on the piston 

as obtained from the indicator card 
L = length of stroke in ft. 
A = area of piston in sq. ins. 

N = number of single strokes per minute or two times the num- 
ber of revolutions' 

PLAN 



Then indicated horse power (i. h. p.) = 



33,000 



Brake Horse Power (b. h. p.) is the actual horse power of an 
engine as measured at the flywheel by a friction brake or dyna- 
mometer. It is the indicated horse power minus the friction of 
the engine. 

Boiler Horse Power. — See Boilers. 

Nominal Horse Power (n. h. p.). — Lloyd's formulae are as follows: 
D = diameter of 1. p. cylinder in ins. 
s = stroke in ins. 
H = heating surface in sq. ft. 
P = working pressure in pounds per sq. in. 
N «= number of cylinders 

(1) Where the boiler pressure and heating surface are known 
*j h n = P + 340 / D 2 y/s H\ w here boiler pressure is be- 
p ' 1000 V 100 ^ 15/ low 160 lb. 

_ P + 590 / D 2 Vs /A w here boiler pressure is 
1500 V 100 "*" 15/ above 160 lb. 
If boilers are fitted with forced or induced draft then H/12 is 
substituted for H/15. 



Digiti 



zed by G00gk 



HORSE POWER 23 

Equivalent Values of Mechanical and Electrical Units 



Unit 


Equivalent Value in 
Other Units 




Unit 


Equivalent Value in 
Other Units 


florae- 
power = 
(h. p.) 


33,000 ft.-lb. per minute 

550 ft.-lb. per second 

746 watts 

.746 kw. 

2,545 heat units (B.t.u.) 

per hour 
42 . 4 heat units per minute 
2.64 lb. water evap. per 
hour, from and at 212° F. 


1 Joule = 
(J) 


1 watt second 
.00134 h. p. second 
.000000278 kw. hour 
.000954 heat units. 
.7372 ft.-lb. 




1 Foot- 
pound = 
(ft.-lb.) 


1.356 joules 
.0000005 h. p. hour 
.000000377 kw. hour 




1,000 watts 

2,654,200 ft.-lb. per hour 
44,232 ft.-lb. per minute 
737 . 2 ft.-lb. per second 
1.34 h. p. 

3,412 heat units per hour 
56 . 9 heat units per minute 
3.53 lb. water evap. per 
hour from and at 212 d F. 


.001285 heat units 
. 1383 kilogram-meter 


1 Kilo- 
watt — 
(kw.) 


1 lb. water 
evaporated 
from and 
at 212° F. 


.379 h.p. hour 
.283 kw. hour 
751,300 ft.-lb. 
967. heat units 
1,019,000 joules 
103,900 kilogram-meters 




1 Kilogram 
meter = 
(kgm.) 




1 British 
Heat Unit 

= (B.t.u.) 


778 ft.-lb. 
.000393 h. p. hour 
.000293 kw. hour 
1048 . watt seconds 
.001036 lb. water evap. 
from and at 212° F. 


.00936 heat units 
7.233 ft.-lb. 
9.8117 joules 
.00000365 h. p. hour 
.00000272 kw. hour 



(2) If boiler pressure and heating surface are not known 

N. h. p. = for simple engines 

loU 



« 5LvT 

120 



for compound engines 



10n for triple and quadruple engines 



. (3) In vessels with Diesel engines 

80 
N X D 2 Vs 



N. h. p. = ^r for single actmg 4-cycle engines 



40 

N X D 2 Vs ~ 
20 



for single acting 2-cycle engines 
for double acting 2-cycle engines 



Shaft Horse Power (s. h. p.) is the power delivered by the engine 
or turbine to the shafting. See Turbines. 

Digitized by vjivJUVLC 



24 



WEIGHTS AND MEASURES 



Effective Horse Power (e. h. p.) See Powering Vessels. 
Thrust Horse Power (t. h. p.) is the power delivered by the pro- 
peller for the propulsion of the ship. Owing to the friction of the 
working parts of the engine and shafting, the horse power trans- 
mitted to the propeller is about \i of the indicated. Horse power 
thrust in lb. X dist. ship travels in ft. in 1 min. 
33000 



used by the propeller = 



Thrust in lb. = 



33000 X h. p. used by the propeller 
dist. ship travels in ft. in 1 min. 



Comparison of Thermometer Scales 



Cent. 


Reau. 


Fahr. 


Cent. 


Reau. 


Fahr. 


Cent. 


Reau. 


Fahr. 


-40 


-32.0 


-40.0 


21 


16.8 


69.8 


62 


49.6 


143.6 


-38 


-30.4 


-36.4 


22 


17.6 


71.6 


63 


50.4 


145.4 


-36 


-28.8 


-32.8 


23 


18.4 


73.4 


64 


51.2 


147.2 


-34 


-27.2 


-29.2 


24 


19.2 


75.2 


65 


52.0 


149.0 


-32 


-25.6 


-25.6 


25 


20.0 


77.0 


66 


52.8 


150.8 


-30 


-24.0 


-22.0 


26 


20.8 


78.8 


67 


53.6 


152.6 


-28 


-22.4 


-18.4 


27 


21.6 


80.6 


68 


54.4 


154.4 


-26 


-20.8 


-14.8 


28 


22.4 


82.4 


69 


55.2 


156.2 


-24 


-19.2 


-11.2 


29 


23.2 


84.2. 


70 


56.0 


158.0 


-22 


-17.6 


- 7.6 


30 


24.0 


86.0 


71 


56.8 


159.8 


-20 


-16.0 


- 4.0 


31 


24.8 


87.8 


• 72 


57.6 


161.6 


-18 


-14.4 


- 0.4 


32 


25.6 


89.6 


73 


58.4 


163.4 


-16 


-12.8 


+ 3.2 


33 


26.4 


91.4 


74 


59.2 


165.2 


-14 


-11.2 


6.8 


34 


27.2 


93.2 


75 


60.0 


167.0 


-12 


- 9.6 


10.4 


35 


28.0 


95.0 


76 


60.8 


168.8 


-10 


- 8.0 , 


14.0 


36 


28.8 


96.8 


77 


61.6 


170.6 


- 8 


- 6.4 


17.6 


37 


29.6 


98.6 


78 


62.4 


172.4 


- 6 


- 4.8 


21.2 


38 


30.4 


100.4 


79 


63.2 


174.2 


- 4 


- 3.2 


24.8 


39 


31.2 


102.2 


80 


64.0 


176.0 


- 2 


- 1.6 


28.4 


40 


32.0 


104.0 


81 


64.8 


177.8 





0.0 


32.0 


41 


32.8 


105.8 


82 


65.6 


179.6 


+ 1 


+0.8 


33.8 


42 


33.6 


107.6 


83 


66.4 


181.4 


2 


1.6 


35.6 


43 


34.4 


109.4 


84 


67.2 


183.2 


3 


2.4 


37.4 


44 


35.2 


111.2 


85 


68.0 


185.0 


4 


3.2 


39.2 


45 


36.0 


113.0 


86 


68.8 


186.8 


5 


4.0 


41.0 


46 


36.8 


114.8 


87 


69.6 


188.6 


6 


4.8 


42.8 


47 


37.6 


116.6 


88 


70.4 


190.4 


7 


5.8 


44.6 


48 


38.4 


118.4 


89 


71.2 


192.2 


8 


6.4 


46.4 


49 


39.2 


120.2 


90 


72.0 


194.0 


9 


7.2 


48.2 


50 


40.0 


122.0 


91 


72.8 


195.8 


10 


8.0 


50.0 


51 


40.8 


123.8 


92 


73.6 


197.6 


11 


8.8 


51.8 


52 


41.6 


125.6 


93 


74.4 


199.4 


12 


9.6 


53.6 


53 


42.4 


127.4 


94 


75.2 


201.2 


13 


10.4 


55.4 


54 


43.2 


129.2 


95 


76.0 


203.0 


14 


11.2 


57.2 


55 


44.0 


131.0 


96 


76.8 


204.8 


15 


12.0 


- 59.0 


56 


44.8 


132.8 


97 


77.6 


206.6 


16 


12.8 


60.8 


57 


45.6 


134.3 


98 


78.4 


208.4 


17 


13.6 


62.6 


58 


46.4 


136.4 


99 


79.2 


210.2 


18 


14.4 


64.4 


59 


47.2 


138.2 


100 


80.0 


212.0 


19 


15.2 


66.2 


60 


48.0 


140.0 








20 


16.0 


68.0 


61 


48.8 


141.8 









y Google 



THERMOMETERS 



25 



Thermometers 
i 

Fahrenheit (F.) thermometer is used in the United States and 
in Great Britain. The freezing point of water is marked 32 and 
the boiling at sea level 212, the distance between these points is 
divided into 180 parts or degrees. 32 parts are marked off from 
the freezing point downwards, and the last one marked or zero. 

Centigrade (C.) is used extensively in Europe and in scientific 
calculations. The freezing point of water is marked 0, and the 
boiling point at sea level 100, and the distance between is divided 
into 100 parts or degrees. 

To convert Fahrenheit readings into Centigrade, subtract 32 
and multiply by f. To convert Centigrade into Fahrenheit 
multiply by I and add 32. 

Reaumur (R.) is used in Russia. The freezing point of water is 
taken as 0, and the boiling point 80. To convert Fahrenheit 
readings into Reaumur subtract 32 and multiply by J. 

To convert Reaumur into Fahrenheit multiply by f and add 32. 

If the temperature be below freezing, "add 32" in the formula 
becomes "subtract from 32" and "subtract 32" becomes "sub- 
tract from 32." See table on page 24. 

Circumferences and Are,:s op Circle Advancing by Eighths 



Diameter 



Circum. 



.3927 
.7864 
1.178 
1.570 
1.963 
2.356 
2.741 
. 3.141 
3.534 
3.927 
4.319 
4.712 
5.105 
5.497 
5.890 
6.283 
6.675 
7.068 
7.461 
7.854 
8.246 
8.639 
9.032 
9.424 



Area 



.0123 

.0491 

.110 

.196 

.306 

.441 

.601 

.785 

.994 

1.227 

1.485 

1.767 

2.074 

2.405 

2.761 

3.141 

3.546 

3.976 

4.430 

4.908 

5.411 

5.939 

6.491 

7.068 



Diameter 



Circum. 



9.817 
10.210 
10.603 
10.996 
11.388 
11.781 
12.174 
12.566 
12.959 
13.352 
13.744 
14.137 
14.530 
14.923 
15.315 
15.708 
16.101 
16.493 
16.886 
17.279 
17.671 
18.064 
18.457 
18.850 



Area 



7.669 
8.295 
8.946 
9.621 
10.321 
11.045 
11.793 
12.566 
13.364 
14.186 
15.033 
15.904 
16.800 
17.728 
18.665 
19.635 
20.629 
21.648 
22.691 
23.758 
24.850 
25.967 
27.109 
28.274 



y Google 



26 WEIGHTS AND MEASURES 

MATHEMATICAL TABLES 
Involution and Evolution 

The quantity represented by the letter a multiplied by a quan- 
tity represented by the letter b, is expressed a X b or ab. 

Quantities in brackets thus (a + b) (a + b) signify they are to 
be multiplied together. 

To square a number multiply the number by itself. Thus the 
square of 4 (often written 4 2 ) is 4 X 4 = 16. 

To cube a number multiply the square by the number. Thus 
cube of 4 (written 4 3 ) = 4X4X4 = 16 X4= 64. 

To find the fourth power of a number, multiply the cube by 
the number. Fourth power of 4 = 64 X 4 = 256. 

The nth power of a number as a n is obtained by multiplying 
the logarithm of the number by n and then finding the number 
corresponding to the logarithm. Thus 5 18 = log. of 5 X 1.8, and 
from the table of logarithms find the number corresponding to this 
logarithm. 

y/~~ isthe radical sign and either with or without the index figure 
2 as \/ indicates that the square root of the quantity under it is 
to be taken. Thus the VI is 2. \/ indicates the cube root is 

to be taken as \/& is 2. \J~ that the fourth root as \/256 is 4. 
The fourth root is the square root of the square root, and the sixth 
root is the cube root of the square root. 

Any root of a number as fya may be obtained by taking the 
logarithm of the number a and dividing it by the index n and from 
the table of logarithms finding the corresponding number. 

To Extract the Square Root of a Number. — Point off the given 
number into periods of two places each beginning with units. If 
there are decimals, point these off likewise beginning at the decimal 
point, and supplying as many ciphers as may be required. 

Find the greatest number whose square is less than the first left- 
hand period, and place it as the first figure in the quotient. Sub- 
tract its square from the left-hand period, and to the remainder 
annex the two figures of the second period for a dividend. 

Double the first figure of the quotient for a partiaj^ivisor. Find 
how many times the latter is contained in the dividend exclusive 
of the right-hand figure, and set the figure representing that num- 
ber of times as the second figure in the quotient and annex it to 
the right of the partial divisor, forming the complete divisor. Mul- 



y Google 



SQUAKE AND CUBE ROOT 27 

tiply this divisor by the second figure in the quotient and subtract 
the product from the dividend. To the remainder bring down 
the next period and proceed as before, in each case doubling the 
figures in the root already found to obtain the trial divisor. Should 
the product of the second figure in the root by the completed di- 
visor be greater than the dividend, erase the second figure both from 
the quotient and from the divisor, and substitute the next smaller 
figure or one small enough to make the second figure by the divisor 
less than or equal to the dividend. 
Find the square root of 3.141592 

3.141592 1 1.772 + square root 
1 



27 


214 

189 


347 


2515 
2429 


3542 


8692 
7084 



To Extract the Cube Root. — Point off the number into periods 
of three figures each, beginning at the right hand or units' place. 
Point off decimals in periods of three figures from the decimal point. 
Find the greatest cube that does not exceed the left-hand period, 
write its root as the first figure in the required root. Subtract 
the cube from the left-hand period, and to the remainder bring 
down the next period for a dividend. 

Square the first figure of the root, multiply by 300, and divide 
the product into the dividend for a trial divisor, write the quotient 
after the first figure of the root as a trial second figure. 

Complete the divisor by adding to 300 times the square of the 
first figure, 30 times the product of the first by the second figure 
and the square of the second figure. Multiply this divisor by the 
second figure, and subtract the product from the remainder. Should 
the product be greater than the remainder the last figure of the root 
and the complete divisor are too large; substitute for the last figure 
the next smaller number and correct the trial divisor accordingly. 

To the remainder bring down the next period, and proceed as 
before to find the third figure of the root; that is, square the two 
figures of the root already found, multiply by 300 for a trial di- 
visor, etc. If the trial divisor is less than the dividend bring down 
another period of three figures, and place in the root and proceed 
as before. 

Digitized by VJiOOQlC 



28 WEIGHTS AND MEASURES 

The cube root of a number, will contain as many figures as there 
are periods of three in the number. 
Find the cube root of 1,881,365 

1,881,365 | 123. -f- cube root 



300 X l 2 ^ = 30Q. 


881 


30X1X2,= 60 


* 


2* - i 
364 


728 


300 X 12 2 - 43200 


153365 


30 X 12 X 3 - 1080 




3 s - 9 




44289 


132867 



[Above examples from Mechanical Engineer's Pocket Book. Wm. Kent.] 

Logarithms 

The logarithm (log.) of a number is the exponent of the power 
to which it is necessary to raise a fixed number or base to produce 
the given number. Thus if the base is 10, the log. of 100 is 2, for 
10 2 = 100. Logarithms having 10 as the base are called common 
or Brigg's logarithms, while those with 2.718281 are hyperbolic or 
Naperian. Common logarithms are given in the table on pages 29-30. 
The hyperbolic log. of a number is equal to the common log. of the 
number X 2.302585. 

With the aid of logarithms, multiplication, division, involution 
and evolution of large numbers may be shortened. Thus, to mul- 
tiply two numbers, add their logarithms, and then find the number 
whose logarithm is their sum. To divide one number into another, 
subtract the logarithm of the smaller from the larger, and find the 
number whose logarithm is the difference, which number will be 
the quotient. 

To raise a number to a given power, multiply the logarithm of 
the number by the exponent of the power, and find the number 
whose logarithm is the product. 

To find any root of a number, divide the logarithm of the number 
by the index of the root, and the quotient will be the logarithm of 
the root; then by referring to the table of logarithms the number 
can be found. 

The logarithm of a number consists of two parts, viz., a whole 
number called the characteristic, and a decimal or mantissa. The 
characteristic is one less than the number of figures to the left 

Digitized by VJiOOQ 1C 



Squares, Cubes, Square Roots, Cube Roots, Logarithms, 
Circumferences and Circular Areas of Nos. from 1 to 50 















No. 


- Dia. 




Square 


Cube 


Square 
Root 


Cube 
Root 


Log. 






No. 


















Circum. 


Area 


1 


1 


1 


1.0000 


1.0000 


0.00000 


3.142 


0.7854 


2 


4 


8 


1.4142 


1.2599 


0.30103 


6.283 


3.1416 


3 


9 


27 


1.7321 


1.4422 


0.47712 


9.425 


7.0686 


4 


16 


64 


2.0000 


1.5874 


0.60206 


12.566 


12.5664 


5 


25 


125 


2.2361 


1.7100 


0.69897 


15.708 


19.6350 


6 


36 


216 


2.4495 


1.8171 


0.77815 


18.850 


28.2743 


7 


49 


343 


2.6458 


1.9129 


0.84510 


21.991 


38.4845 


8 


64 


512 


2.8284 


2.0000 


0.90308 


25.133 


50.2655 


9 


81 


729 


3.0000 


2.0801 


0.95424 


28.274 


63.6173 


10 


100 


1000 


3.1623 


2.1544 


1.00000 


31.416 


78.5398 


11 


121 


1331 


3.3166 


2.2240 


1.04139 


34.558 


95.0332 


12 


144 


1728. 


3.4641 


2.2894 


1.07918 


37.699 


113.097 


13 


169 


2197 


3.6056 


2.3513 


1.11394 


40.841 


132.732 


14 


196 


2744 


3.7417 


2.4101 


1.14613 


43.982 


153.938 


15 


225 


3375 


3.8730 


2.4662 


1.17609 


47.124 


176.715 


16 


256 


4096 


4.0000 


2.5198 


1.20412 


50.265 


201.062 


17 


289 


4913 


4.1231 


2.5713 


1.23045 


53.407 


226.980 


18 


324 


5832 


4.2426 


2.6207 


1.25527 


56.549 


254.469 


19 


361 


6859 


4.3589 


2.6684 


1.27875 


59.690 


283.529 


20 


400 


8000 


4.4721 


2.7144 


1.30103 


62.832 


314.159 


21 


441 


9261 


4.5826 


2.7589 


1.32222 


65.973 


346.361 


22 


484 


10648 


4.6904 


2.8020 


1.34242 


96.115 


380.133 


23 


529 


12167 


4.7958 


2.8439 


1.36173 


72.257 


415.476 


24 


576 


13824 


4.8990 


2.8845 


1.38021 


75.398 


452.389 


25 


625 


15625 


5.0000 


2.9240 


1.39794 


78.540 


490.874 


26 


676 


17576 


5.0990 


2.9625 


1.41497 


81.681 


530.929 


27 


729 


19683 


5.1962 


3.0000 


1.43136 


84.823 


572.555 


28 


784 


21952 


5.2915 


3.0366 


1.44716 


87.965 


615.752 


29 


841 


24389 


5.3852 


3.0723 


1.46240 


91.106 


660.520 


30 


900 


27000 


5.4772 


3.1072 


1.47712 


94.248 


706.858 


31 


961 


29791 


5.5678 


3.1414 


1.49136 


97.389 


754.768 


32 


1024 


32768 


5.6569 


3.1748 


1.50515 


100.531 


804.248 


33 


1089 


35937 


5.7446 


3.2075 


1.51851 


103.673 


855.299 


34 


1156 


39304 


5,8310 


3.2396 


1.53148 


106.814 


907.920 


35 


1225 


42875 


5.9161 


3.2711 


1.54407 


109.956. 


962.113 


36 


1296 


46656 


6.0000 


3.3019 


1.55630 


113.097 


1017.88 


37 


1369 


50653 


6.0828 


3.3322 


1.56820 


116.239 


1075.21 


38 


1444 


54872 


6.1644 


3.3620 


1.57978 


119.381 


1134.11 


39 


1521 


59319 


6.2450 


3.3912 


1.59106 


122.522 


1194.59 


40 


1600 


64000 


6.3246 


3.4200 


1.60206 


125.66 


1256.64 


41 


1681 


68921 


6.4031 


3.4482 


1.61278 


128.81 


1320.25 


42 


1764 


74088 


6.4807 


3.4760 


1.62325 


131.95 


1385.44 


43 


1849 


79507 


6.5574 


3.5034 


1.63347 


135.09 


1452.20 


44 


1936 


85184 


6.6332 


3.5303 


1.64345 


138.23 


1520.53 


45 


2025 


91125 


6.7082 


3.5569 


1.65321 


141.37 


1590.43 


46 


2116 


97336 


6.7823 


3.5830 


1.66276 


144.51 


1661.90 


47 


2209 


103823 


6.8557 


3.6088 


1.67210 


147.65 


1734.94 


48 


2304 


110592 


6.9282 


3.6342 


1.68124 


150.80 


1809.56 


49 


2401 


117649 


7.0000 


3.6593 


1.69020 


153.94 


1885.74 


50 


2500 


125000 


7.0711 


3.6840 


1.69897 


157.08 


1963.50 



of the decimal point in the number whose logarithm is to be found. 
Thus the -characteristic of numbers from 1 to 9.999 is 0, from 10 to 
99.999 is 1, and so on. Should the number be a decimal with no 
figures to the left of the decimal point, then the characteristic is 
negative and is equal to the number of places the first figure is from 

<j/\ Digitized by VjUUV 



Squares, Cubes, Square Roots, Cube Roots, Logarithms, 
Circumferences and Circular Areas of Nos. from 51 to 100 















No. 


= Dia. 




Square 


Cube 


Square 
Root 


Cube 
Root 


Log. 






No. 


















Circum. 


Area 


51 


2601 


132651 


7.1414 


3.7084 


1.70757 


160.22 


2042.82 


52 


2704 


140608 


7.2111 


3.7325 


1.71600 


163.36 


2123.72 


53 


2809 


148877 


7.2801 


3.7563 


1.72428 


166.50 


2206.18 


54 


2916 


157464 


7.3485 


3.7798 


1.73239 


169.65 


2290.22 


55 


3025 


166375 


7.4162 


3.8030 


1.74036 


172.79 


2375.83 


56 


3136 


175616 


7.4833 


3.8259 


1.74819 


175.93 


2463.01 


57 


3249 


185193 


7.5498 


3.8485 


1.75587 


179.07 


2551.76 


58 


3364 


195112 


7.6158 


3.8709 


1.76343 


182.21 


2642.08 


59 


3481 


205379 


7.6811 


3.8930 


1.77085 


185.35 


2733.97 


60 


3600 


216000 


7.7460 


3.9149 


1.77815 


188.50 


2827.43 


61 


3721 


226981 


7.8102 


3.9365 


1.78533 


191.64 


2922.47 


62 


3844 


238328 


7.8740 


3.9579 


1.79239 


194.78 


3019.07 


63 


3969 


250047 


7.9373 


3.9791 


1 . 79934 


197.92 


2117.25 


64 


4096 


262144 


8.0000 


4.0000 


1.80618 


201.06 


3216.99 


65 


4225 


274625 


8.0623 


4.0207 


1.81291 


204.20 


3318.31 


66 


4356 


287496 


8.1240 


4.0412 


1.81954 


207.35 


3421.19 


67 


4489 


300763 


8.1854 


4.0615 


1.82607 


210.49 


3525.65 


68 


4624 


314432 


8.2462 


4.0817 


1.83251 


213.63 


3631.68 


69 


4761 


328509 


8.3066 


4.1016 


1.83885 


216.77 


3739.28 


70 


4900 


343000 


8.3666 


4.1213 


1.84510 


219.91 


3848.45 


71 


5041 


357911 


8.4261 


4.1408 


1.85126 


223.05 


3959.19 


72 


5184 


373248 


8.4853 


4.1602 


1.85733 


226.19 


4071.50 


73 


5329 


389017 


8.5440 


4.1793 


1.86332 


229.34 


4185.39 


74 


5476 


405224 


8.6023 


4.1983 


1.86923 


232.48 


4300.84 


75 


5625 


421875 


8.6603 


4.2172 


1.87506 


235.62 


4417.86 


76 


5776 


438976 


8.7178 


4.2358 


1.88081 


238.76 


4536.46 


77 


5929 


456533 


8.7750 


4.2543 


1.88649 


241.90 


4656.63 


78 


6084 


474552 


8.8318 


4.2727 


1.89209 


245.04 


4778.36 


79 


6241 


493039 


8.8882 


4.2908 


1.89763 


248.19 


4901.67 


80 


6400 


512000 


8.9443 


4.3089 


1.90309 


251.33 


5026.55 


81 


6561 


531441 


9.0000 


4.3267 


1.90849 


254.47 


5153.00 


82 


6724 


551368 


9.0554 


4.3445 


1.91381 


257.61 


5281.02 


83 


6889 


571787 


9.1104 


4.3621 


1.91908 


260.75 


5410.61 


84 


7056 


592704 


9 . 1652 


4.3795 


1.92428 


263.89 


5541.77 


85 


7225 
7*396 


614125 


9.2195 


4.3968 


1.92942 


267.04 


5674.50 


86 


636056 


9.2736 


4.4140 


1.93450 


270.18 


5808.80 


87 


7569 


658503 


9.3274 


4.4310 


1.93952 


273.32 


5944.68 


88 


7744 


681472 


9.3808 


4.4480 


1.94448 


276.46 


6082.12 


89 


7921 


704969 


9.4340 


4.4647 


1.94939 


279.60 


6221.14 


90 


8100 


729000 


9.4868 


4.4814 


1.95424 


282.74 


6361.73 


91 


8281 


753571 


9.5394 


4.4979 


1.95904 


285.88 


6503.88 


92 


8464 


778688 


9.5917 


4.5144 


1.96379 


289.03 


6647.61 


93 


8649 


804357 


9.6437 


4.5307 


1.96848 


292.17 


6792.91 


94 


8836 


830584 


9.6954 


4.5468 


1:97313 


295.31 


6939.78 


95 


9025 


857375 


9.7468 


4.5629 


1.97772 


298.45 


7088.22 


96 


9216 


884736 


9.7980 


4.5789 


1.98227 


301.59 


7238.23 


97 


9409 


912673 


9.8489 


4.5947 


1.98677 


304.73 


7389.81 


98 


9604 


941192 


9.8995 


4.6104 


1.99123 


307.88 


7542.96 


99 


9801 


970299 


9.9499 


4.6261 


1.99564 


311.02 


7697.69 


100 


10000 


1000000 


10.0000 


4.6418 


2.00000 


314.16 


7852.98 



the decimal point. Thus the characteristic of numbers from .1 
to .999 is - 1, from .01 to .099 is - 2, .0000072 is - 6, etc. The 
mantissa or decimal part is only given in the table/ the decimal 
point being omitted. The minus sign is frequently placed above 
the characteristic thus: log. .31830 = 1.50285 or 9.50285 - 10. 



30 



JvJ\JvI^ 



GEOMETRICAL PROPOSITIONS 31 

If a number is multiplied or divided by any integral power of 
10, producing another number with the same sequence of figures, 
the mantissae of their logarithms will be equal. To find the logarithm 
of a number take from the table the mantissa corresponding to its 
sequence of figures, and the characteristic may be prefixed by the 
rule given above. 

Thus if log. of 3.053 = .484727 

log. 30.53 = 1.484727 log. .3053 - 9.484727 -10 
log. 305.3 =2.484727 log. .03053 =8.484727-10 
log. 3053. = 3.484727 log. .003053 = 7.484727 -10 

The above property is only enjoyed by the common or Brigg's 
logarithms and constitutes their superiority over other systems of 
logarithms. 

-Geometrical Propositions 

The sum of the angles of a triangle is equal to 180°. 

If a triangle is equilateral it is equiangular. 

In a right-angled triangle the square on the hypothenuse is equal 
to the sum of the squares of the other two sides. 

A straight line from the vertex of an isosceles triangle perpendicu- 
lar to the base bisects the base and the vertical angle. 

A circle can be drawn through any three points not in the same 
straight line. 

If a triangle is inscribed M in a semicircle, it is right-angled. 

In a quadrilateral the sum of the interior angles is equal to four 
right angles or 360°. 

In a parallelogram the opposite sides are equal, as also the oppo- 
site angles are equal. 

A parallelogram is bisected by its diagonals, which in turn are 
bisected by each other. . 

If the sides of a polygon are produced, then the sum of the exterior 
angles is equal to four right angles. 

The areas of two circles are to each other as the squares of their 
radii. 

If a radius is perpendicular to a chord, it bisects the chord and 
the arc subtended by the chord. 

From a point without a circle only two tangents can be drawn 
to the circle. The tangents so drawn are equal. 

A straight line tangent to a. circle meets it at one point, and it 
is perpendicular to the radius drawn to that point. 



Digitized 



by Google 



32 WEIGHTS AND MEASURES 

If an angle is formed by a tangent and a chord, it is measured 
by one-half of the arc intercepted by the chord. 

If an angle at the circumference of a circle between two chords 
is subtended by the same arc as an angle at the center between 
two radii, the angle at the circumference is equal to half the angle 
at the center. 

Properties op Circles and Ellipses 

Circle. — The ratio of the circumference of a circle to its diameter 

is 3.141592 and is represented by the symbol ir (called Pi) 

Circumference of a circle = diameter X 3.14159 

Diameter of circle X .88623 1 ., - , 

Circumference of circle X .28209 } = Slde of equal 8quaXe 

Circumference of circle X 1.1284 = perimeter of equal square 

Side of square of equal periphery as circle = diameter X .7854 

Diameter of circle circumscribed about square = side X 1.4142 

Side of square inscribed in circle = diameter X .70711 

To find the length of an arc of a circle, multiply the diameter 

of the circle by the number of degrees in the arc and this product 

by .0087266. Or let C represent the length of the chord of the 

arc and c the length of the chord of half the arc, then the length 

t *u 8c - C 
of the arc = — 5 

Chord of the arc = 2 X radius X sin angle ^g"* 8 

Rise (the perpendicular di stance from the center of t he chord 

to the arc) = radius — X A V 4 radius 2 — length of chord 2 

o w j- w • 9 an 8 le in degrees 

= 2 X radius X sin 2 — -. — - 

4 

For areas of segments and sectors see Areas. 

x = 3.1415926 log. = 0.497149 

ir __ 

T ~~ 

1 = 

x 

ir _ 
180 ~ 
180 



.7853982 


log. = 1.895090 


.0318309 


log. = T.5028501 


.0174533 


log. = 2.2418774 


57.2957795 


log. - 1.7581226 




Digitized by VjiOOQ 1C 



AREAS 33 



Ellipse. Let D «= major axis 
d *s minor axis 



Approximate circumference = 3.1416 y ^ — 

Area = D XdX .78539 
_ ££* X 3.14159 

Areas of Plane Figures and Surfaces of Solids 
Plane Figures. 

Triangle = b ase X Vi altitude 

= y/ s (s — a) (a — b) (a — c) where 8 = J^ sum 
of the three sides a, b and c 
Parallelogram = base X altitude 

Trapezoid = altitude X 14 the sum of the parallel sides 

Trapezium = divide into two triangles and find area of the 

triangles 
Circle = diameter 2 X .7854 = x X radius 2 

Sector of circle = length of arc X \i the radius 

_ it X radius 2 X angle in degrees ^.^ ^ 

360 = - 0087266 x 

radius 2 X angle in degrees 
Segment of circle. — Where the line forming the segment cuts the 
circle, draw lines to the center forming a sector and a center angle A. 

r™ - , radius 2 /3. 1416 X A in degrees . A 
Then area of segment = — ^ — 1 ioq ~ — — sm A 1 

Circle of same area as square: diameter = side X 1.12838 

Square of same area as circle: side — diameter X .88623 

Ellipse = long diameter X short diameter X .7854 

Parabola = base X % perpendicular height. 

Regular polygon = sum of its sides X perpendicular from its 
center to one of its sides divided by 2. Or multiply J^ the 
perimeter by the perpendicular from the center to a side. 

Irregular polygon: draw diagonals dividing it into triangles, and 
find the sum of the areas of the triangles. 

Trapezoidal Rule. — To find the area of a curvilinear figure, as 
ABC D (see Fig. 1), divide the base into any number of con- 
venient equal parts, and erect perpendiculars meeting the curve. 
To the half sum of the first and last perpendiculars add the sum of 
all the intermediate ones; then the sum multiplied by the common 
interval will give the area. 

Digitized by VjOOQIC 



34 



WEIGHTS AND MEASURES 



m j j i r 

t ^ T V *» » * 

Figure 1 

Let 7i = the common interval 

2/i, ffc) etc., lengths of the perpendiculars to the line A D 

Then the area A B C D = h {^^ + 2/2 + 2/* + 2/4 + 2/5 + 2/e) 

Simpson's First Rule. — This rule assumes that the curved line 
B C forming one side of the curvilinear area A B C D (see Fig. 2) 
is a portion of a curve known as a parabola of the second order 
whose equation is y = ax 2 + bx + c. 




Figure 2 



Divide the base into any convenient even number of parts, and 
erect perpendiculars to meet the curve. To the sum of the end 
perpendiculars or ordinates add four times the even numbered 
ordinates and twice the odd numbered ordinates. Multiply the 
sum by one-third the common interval and the product will be 
the area. 

Thus the area A B C D in Fig. 2=4" (2/1 + %2 + yz) 

o 

Or the area of A B C D in Fig. 1 = y (y x + 42/ 2 + 2y*+ 4y 4 + 2y h 

+ 42/6+ 2/7) 



Digiti 



zed by G00gk 



SIMPSON'S SECOND RULE 



35 



It is found that areas given by the above approximate rule for 
curvilinear figures are very accurate, and the rule is extensively 
used in ship calculations. 



Example. The ordinates to a curve are 1.5, 3.1, 5.2, 6.0, 6.5, 7.0, 8.1, 8.5 
.ad 9 .0 ft., the common interval is 3 ft. Find the area. 


Number of 
Ordinate 


Length of 
Ordinate 


Simpson's 
Multipliers 


Functions of 
Ordinates 


1 


1.5 
3.1 
5.2 
6.0 
6.5 
7.0 
8.1 
8.5 
9.0 


1 
4 
2 
4 
2 
4 
2 
4 
1 


1 5 


2 


12 4 


3 


10 4 


4 


24 


5 


13 


6 


28 


7 


16 2 


8 


34 


9 


9.0 



Common interval » 3 ft. 

Then the area = H X 3 X 148.5 = 148.5 aq. ft. 



148.5 



. The multipliers may be ^ of those given in the example, viz., 
1 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, Yz and the sum of the functions multiplied 
by % the common interval as above. The H multipliers are in 
some cases easier to work with, as the sum of the functions is a 
smaller number. 

Simpson's Second Rule assumes that the curve B C (see Fig. 3) 
is part of a parabola of the third order, where y — ax + bx + ex. 



LLU, 



Figure 3 



Sh 



The area of the curve A B C D y Fig. 3, is -g- {yi + Zy 2 + Sy» + 2/0 

or the curve in Fig. 1 is -g- (y x + 3y 2 + 3y 8 + 2t/ 4 + 32/5+ 3i/ 6 + t/ 7 ) 
Here the number of ordinates must be a multiple of 3 plus 1. 

Digitized by VjiOOQIC 



36 WEIGHTS AND MEASURES 

Simpson's first rule is used more than the second as it is simpler 
and is quite as accurate. 

Surface of Solids. — Lateral surface of a right or oblique prism 
or cylinder = perimeter of the base X lateral length. To get the 
total surface add the areas of the bases to the lateral surface. 

Pyramid or cone, right and regular, lateral surface = perimeter 
of base X X A slant height. To get total surface add area of base. 

Frustum of pyramid or cone, right and regular parallel ends, 
lateral surface = (sum of perimeters of base and top) X M slant 
height. To get total surface add areas of the bases to the lateral 
surface. 

Surface of a sphere = 4 ir radius 2 = w diameter 8 . 

Surface of spherical sector = J^ x r (4 6 + c). See Fig. 4. 

Surface of a spherical segment = 2 *• r 6 =■ % * (4 6 2 + c 2 ). See 
Fig. 5. 

Surface of a spherical zone = 2 w r b. See Fig. 6. 

Surface of a circular ring = 4 ir 2 R r. See Fig. 7. 

Surface of a regular polyhedron (a solid whose sides are equal 
regular polygons) = area of one of the faces X the number of faces. 

Volumes of Solids 

Prism, right or oblique regular or irregular. — Volume = area of 
section perpendicular to the sides X the lateral length of a side. 

Cylinder, right or oblique, circular or elliptic, etc. — Volume = 
area of section perpendicular to the sides X the lateral length of 
a side. 

Frustum of any prism or cylinder. — Volume = area of base X 
perpendicular distance from base to center of gravity of opposite 
face. 

Pyramid or cone, right or oblique, regular or irregular. — Volume 
= area of base X H the perpendicular height. 

Frustum of any pyramid or cone, parallel ends. — Volume = 
(sum of the areas of base and top plus the square root of their 
products) X H the perpendicular height. 

Wedge, parallelogram face. — Volume = sum of three edges X 
perpendicular height X perpendicular width. 

Sphere. — Volume = }x (radius) 8 or (diameter) 8 X .5236. 

Digitized by VjiOOQIC 



VOLUMES OF SOLIDS 



37 




Volume - 3i x r* b . 



Figure 4 

Spherical Sector 




Volume - \i ir 6* (3 r - 6) 



Figure 5 
Spherical Segment 



—I 

5 



Volume = ^ x 6 (3a*+ 3c»+ 46») 



Figured 
Spherical Zone 





^-/? — ihA* 


b 


d 



Volume - 2 ** 22 r« 



Figure 7 

Circular King 
3 



Digiti 



zed by G00gk 



38 



WEIGHTS AND MEASURES 




Volume » \4 rrab 



V-^r^£*%j 



Figure 8 

Ellipsoid 




Volume = % x r 8 h 



Figure 

Paraboloid 



Regular polyhedron. — Volume = area of its surface X H the per- 
pendicular from the center to one of the faces. 

The volume of any irregular prismatic solid may be obtained by 
dividing it into prisms or other bodies whose contents can be calcu- 
lated by the above formulae. The sum of the contents of these 
bodies will give the total volume of the solids. 

To find the volume of a solid bounded by a curved surface, as the 
underwater portion of a ship's hull, divide the solid by a series of 
planes or sections spaced an equal distance apart. 

The area of each section can be calculated by either the tra- 
pezoidal or Simpson's rule, or by means of an instrument called a 
planimeter. The areas of the sections can be laid off on ordinates 
which are spaced the same distance apart as the sections which 
the body was divided into. A curve is drawn through the points 
laid off on the ordinates, and the area of the curvilinear figure is 
the volume of the solid. 

Example. The areas of cross sections of a ship below the load water line are 1.2, 
17.6, 41.6, 90.7, 134.3, 115.4. 61.7, 30.4 and 6.6 sq. ft. The sections are 0.5 ft. 
apart. Find the volume in cubic feet, and the displacement in tons of salt water. 



Digitized by > 



JvJ^Vl^ 



TRIGONOMETRY 



39 



Number of Section 


Area 


Simpson's 
Multipliers 


Functions of Areas 


1 


1.2 

17.6 

41.6 

90.7 

134.3 

115.4 

61.7 

30.4 

6.6 


1 
4 
2 
4 
2 
4 
2 
4 
1 


1.2 


2 


70.4 


3 


83.2 


4 


362.8 


5 


268.6 


6 


661.6 


7 


123 4 


8 


121.6 


9 


6.6 








1,699.4 



Volume - X X 9.5 ft. X 1,699.4 = 5,381.4 cu. ft. 
5,381.4 

Displacement = = 153.7 tons 

35 

To find the volume of a cross coal bunker or a side bunker having 
the same cross section throughout, divide the height into inter- 
vals and calculate the area of the section by Simpson's first rule. 
Multiply the area thus found by the length of the bunker, giving 
the capacity in cubic feet. To convert this into tons divide by 
42, as 42 cu. ft. is usually taken as one ton of 2240 lb. 




Trigonometry 

The complement of an angle or arc is what remains after sub- 
tracting the angle or arc from 90°. If an arc is represented by A, 
its complement is 90° —A. Hence the complement of an arc that 
exceeds 90° is negative. 

The supplement of an angle or arc is what remains after sub- 
tracting the angle or arc from 180°. If A is an arc, its supplement 
is 180° —A. The supplement of an arc that exceeds 180° is negative. 



jvJ^v^ 



40 WEIGHTS AND MEASURES 

As the sum of the three angles of a triangle is equal to 180°, any 
angle is the supplement of the other two. 

Trigonometric Functions. — In the right triangle (Fig. 10) if A 
is one of the acute angles, a the opposite side, b the adjacent side 
and c the hypotenuse, 

sineof angle A . yorfte side _ a 

hypotenuse c 

cosineofangle A - ^jacentside . ± 
hypotenuse c 

tangent of angle A - ^B2g*gJ^ » _ « 
-^y. adjacent side b 

cotangent of angle A - ^jacent^e . ± 
opposite side a 

seeantof angle A = hypotenuse _ e 
adjacent side o 

cosecant of angle A - ^^"j* - -£■ 
opposite side <* 

versed sine of angle A — 1 — cosine A 

exsecant of angle A — secant A — 1 

For angle B 



a 

b 

tan B - - 
a 

cosec £ — 4" 
o 

tan A — cotan B — -r- cosec A = sec 2* =» — ■' 

6 a 

If a circle is divided into four quadrants, the upper right-hand 
quadrant is called the first, the upper left the second, the lower 
left the third, and the lower right the fourth. The signs of the 
functions in the four quadrants are as follows: 



sin B — — 
c 








cotan B — 


coeB -i 
c 








sec £ - 


tanfl - -^ 
a 








cosec £ — 


sin A = cos 


B 


- 


C 


cotan A =» 


cos A — sin 


B 


- 


b^ 

c 


sec A — 



OBLIQUE TRIANGLES 41 

First Second Third Fourth 

Sine and cosecant + + — — • 

Cosine and secant -f — — + 

Tangent and cotangent + — + — 

The symbol sin' 1 ^ means the angle whose sine is x, and is read 
inverse sine of x and anti sine of x (also arc sine x). Similarly 
cos _1 x, tan~ l z, etc. While the direct functions sine, cos, etc., are 
single valued, the indirect are many, thus sin 30° = .5, but sin _1 .5 = 
30° or 150°. 

If an acute angle and one side or if two sides of a right triangle 
are given the other elements can be determined. Let A and B be 
acute angles (see Fig. 10), a and b the sides opposite them. The 
acute angles are complementary, that is A + B = 90°. ~Five cases 
may be distinguished. 

Given c and A then a — c sin A, b » e cos B 
a " A b = a cot A, c = a cosec A 

b " A a = b tan A, c — b sec A 

a " c A - sin" 1 y, 6 =V( c +a) ( c -a) 

a " b A - tan _1 y, c - Vtf+& 

Solution of Oblique Triangles. — If any three of the six elements 
(three angles and three sides) of a triangle are known, the remain- 
ing three can be found, provided one of the given three is a side. 
There are four cases as follows: 

Case 1. Given one side and two angles. 

The third angle equals 180° minus the sum of the two given. 

-r* xu • • j u *v * a sin B , a sin C 

If the given side be a then 6 — —. — j- and c « — - : — r- 

sm A Bin A 

Case 2. Given two sides (a and b) and the included angle C. 

Then A = H (A + B) + Yz (A - B) 

B - H(A+H) -H(A -£) 

a sin C 

c -= — : — j- 
sm A 

Case S. Given two sides a and 6, and the angle A opposite one 
of them. 

sin B « — sin A giving two values of B, one acute and one 
a 

obtuse unless sin B > 1 in which case the data are impossible. Call- 
ing these two values 2?i and B 2 , then 



Digiti 



zed by G00gk 



42 WEIGHTS AND MEASURES 

corresponding to B h d = 180 — (A + #)i and ci = — — j^ 

sin A 



B„ ft = 180 - (A + *), 



a sin ft . 



sin A 
That is, there are two solutions unless ft<0 when only the first 

holds. A triangle should be constructed as then the two solutions 

will become more evident. 

Case 4. Given the three sides. Let * = }4 (<* + b + c) 



Then cos }4 A - i /* ( * ~ a) 
r 6c 



%£ -|/t 



6c 



cosHC»4/L(i^l> 
f ab 



There are two kinds of trigonometrical tables for the computa- 
tion of the sides and angles of a triangle, viz., natural sines, tan- 
gents, etc., and logarithmic sines, tangents, etc. Natural sines, 
tangents, etc., are calculated for a circle whose radius is unity, 
and logarithmic sines, tangents, etc., for a circle whose radius is 
10,000,000,000. With natural sines long operations in multipli- 
cation and division are necessary, while with logarithmic sines 
these operations in conjunction with a table of logarithms are 
reduced to addition and subtraction. 

Trigonometric Formulae. — tan A ■■ -p sec A a — 

B cos A cos A 

tan A = — 7 r cotan A = — — -r cosec A 



— cotan A— sin A sin A 

sin 1 A + cos* A = 1 

i + tan* A « sec* A 1 + cotan* A = cosec 1 A 

sin (A + B) = sin A cos B + cos A sin B 

cos (A + B) = cos A cos B — sin A sin B 

sin (A — B) =■ sin A cos B — cos A sin B 

cos (A — B) = cos A cos B + sin A sin B 

2 tan A 



sin 2 A = 2 sin A cos A tan 2 A 
cos 2 A a cos* A — sin 1 A cotan 2 A 



1 -tan 2 A 
cot* A - 1 

2 cotan A 



aia^-*, / 1 -^ tan HA^i /)-^ 
V 2 V 1 + cos A 

cos A 



cos J^ A - ± |/L±|°lii C otan H A = ± j/^ 



Digiti 



cos A 

zed by G00gk 



SINES, COSECANTS, TANGENTS, ETC. 43 

Natural Sines, Cosecants, Tangents, etc. 



• 


1 


Sine 


Cosecant 


Tangent 


Cotangent 


Secant 


Cosine 


• 


o 








.000000 


Infinite. 


.000000 


Infinite. 


1.00000 


1.000000 





M 




10 


.002909 


343.77516 


.002909 


343.77371 


1.00000 


999996 


50 






20 


.005818 


17188831 


.006818 


171.88540 


1.00002 


999983 


40 






30 


.008727 


114.59301 


.008727 


114.58865 


1.00004 


'. 999962 


30 






40 


.011635 


85.945609 


.011636 


85.939791 


1.00007 


.vWtMJ 


20 






50 


.014544 


68.757360 


.014545 


68.750087 


1JD0011 


.999894 


10 




1 





.017452 


57.298688 


.017455 


57.289962 


1.00015 


.999848 





89 




10 


.020361 


49.114062 


.020365 


49.103881 


1.00021 


.999793 


50 






20 


.023269 


42.975713 


.023275 


42.964077 


1.00027 


.999729 


40 






30 


.026177 


38.201550 


.026186 


38.188459 


1.00034 


.999657 


30 






40 


.029085 


34.382316 


.029097 


34.367771 


1.00042 


.999577 


20 






50 


.031992 


31.257577 


.032009 


31.241577 


1.00051 


.999488 


10 




2 





.034899 


28.653708 


.034921 


28.636253 


1.00061 


.999391 





88 




10 


.037806 


26.450510 


.037834 


26.431600 


1.00072 


.999285 


50 






20 


.040713 


24.562123 


.040747 


24.541758 


1.00083 


.999171 


40 






30 


.043619 


22.925586 


.043661 


22.903766 


1.00095 


.999048 


30 






40 


.046525 


21.493676 


.046576 


21.470401 


1.00108 


.998917 


20 






50 


.049431 


20.230284 


.049491 


20.205553 


1.00122 


.998778 


1C 




3 





.052336 


19.107323 


.052408 


19.081137 


1.00137 


.998630 





87 




10 


.055241 


18.102619 


.055325 


18.074977 


1.00153 


.998473 


50 






20 


.058145 


17.198434 


.058243 


17.169337 


1.00169 


.998308 


40 






30 


.061049 


16.380408 


.061163 


16.349855 


1.00187 


.998135 


30 






40 


.063952 


15.636793 


.064083 


15.604784 


1.00205 


.997357 


20 






50 


.066854 


14.957882 


.067004 


14.924417 


1.00224 


.997763 


10 




4 





.069756 


14.335587 


.069927 


14.300666 


1.00244 


.997564 





86 




10 


.072658 


13.763115 


.072851 


13.Z26738 


1.00265 


.997357 


50 






20 


.075559 


13.234717 


.075776 


13.196888 


1.00287 
1.00309 


.997141 


40 






30 


.078459 


12.745495 


.078702 


12.706205 


.996917 


30 






40 


.081359 


12.291252 


.081629 


12.250505 


1.00333 


.996685 


20 






50 


.084258 


11.868370 


.084558 


11.826167 


1.00357 


.996444 


10 




5 





.087156 


11.473713 


.087489 


11.430052 


1.00382 


.996195 





85 




10 


.090053 


11.104549 


.090421 


11.059431 


1.00408 


.995937 


50 






20 


.092950 


10.758488 


.093354 


10.711913 


1.00435 


.995671 


40 






30 


.095846 


10.433431 


.096289 


10.385397 


1.00463 


.995396 


30 






40 


.098741 


10.127522 


.099226 


10.078031 


1.00491 


.995113 


20 






50 


.101635 


9.8391227 


.102164 


9.7881732 


1.00521 


.994822 


10 




• 





.104528 


9.5667722 


.105104 


9.5143645 


1.00551 


.994522 





84 




10 


.107421 


9.3091699 


.108046 


9.2553035 


1.00582 


.994214 


50 






20 


.110313 


9.0651512 


.110990 


9.0098261 


1.00614 


.993897 


40 


83 


o 


i 


Cosine 


Secant 


Cotangent 


Tangent 


Cosecant 


Sine 


' 


o 



For functions from 83° 40' to 90° read from bottom of table upwwd. 

Digitized by VJiOOQLC 



U WEIGHTS AND MEASURES 

Natural Sines, Cosecants, Tangents, etc. — Continued 



o 


/ 


Sine 


Cosecant 


Tangent 


Cotangent 


Secant 


Cosine 


' 


e 


6 


30 


.113203 


8.8336715 


.113936 


8.7768874 


1.00647 


.993572 


30 






40 


.110093 


8.6137901 


.116883 


8.5555468 


1.00681 


.993238 


20 






60 


.118982 


8.4045586 


.119833 


8.3449558 


1.00715 


.992896 


10 




7 





.121869 


8.2055090 


.122785 


8.1443464 


1.00751 


.992546 





83 




10 


.124756 


8.0156450 


.125738 


7.9530224 


1.00787 


.992187 


50 






20 


.127642 


7.8344335 


.128694 


7.7703506 


1.00825 


.991820 


40 






30 


.130526 


7.6612976 


.131653 


7.5957541 


1.00863 


.991445 


30 






40 


.133410 


7.4957100 


.134613 


7.4287064 


1.00902 


.991061 


20 






50 


.136292 


7.3371909 


.137576 


7.2687255 


1.00942 


.990669 


10 




8 





.139173 


7.1852965 


.140541 


7.1153697 


1.00983 


.990268 





82 




10 


.142053 


7.0396220 


.143508 


6.9682335 


1.01024 


.989859 


50 






20 


.144932 


6.8997942 


.146478 


6.8269437 


1.01067 


.989442 


40 






30 


.147809 


6.7654691 


.149451 


6.6911562 


1.01111 


.989016 


30 






40 


.150686 


6.6363293 


.152426 


6.5605538 


1.01155 


.988582 


20 






60 


.153561 


6.5120812 


.155404 


6.4348428 


1.01200 


.988139 


10 




9 





.156434 


6.3924532 


.158384 


63137515 


1.01247 


.987688 





81 




10 


.159307 


6.2771933 


.161368 


6.1970279 


1.01294 


.987229 


50 






20 


.162178 


6.1660674 


.164354 


6.0844381 


1.01342 


.986762 


40 






30 


.165048 


6.0588980 


.167343 


5.9757644 


1.01391 


.986286 


30 






40 


.167916 


5.9553625 


.170334 


5.8708042 


1.01440 


.965801 


20 






50 


.170783 


5.8553921 


.173329 


5.7693688 


1.01491 


.985309 


10 




* 10 % 





.173648 


5.7587705 


.176327 


5.6712813 


1.01543 


.984808 





80 




10 


.176512 


5.6653331 


.179328 


5.5763786 


1.01595 


.984298 


50 






20 


.179375 


5.5749258 


.182332 


5.4845052 


1.01649 


.983781 


40 






30 


.182236 


5.4874043 


.185339 


5.3955172 


1.01703 


.983255 


30 






40 


.185095 


5.4026333 


.188359 


5.3092793 


1.01758 


.982721 


20 






50 


.187953 


5.3204860 


.191363 


5.2256647 


1.01815 


.982178 


10 




11 





.190809 


5.2408431 


.194380 


5.1445540 


1.01872 


.981627 





70 




10 


.193664 


5.1635924 


.197401 


5.0658352 


1.01930 


.981068 


50 






20 


.196517 


5.0886284 


.200425 


4.9894027 


1.01989 


.980500 


40 






30 


.199368 


5.0158317 


.203452 


4.9151570 


1.02049 


.979925 


30 






40 


.202218 


4.9451687 


.206483 


4.8430045 


1.02110 


.979341 


20 






50 


.205065 


4.8764907 


.209518 


4.7728568 


1.02171 


.978748 


10 




1» 





.207912 


4.8097343 


.212557 


4.7046301 


1.02234 


.978148 





78 




10 


.210756 


4.7448206 


.215599 


4.6382457 


1.02298 


.977539 


50 






20 


.213599 


4.6816748 


.218645 


4.5736287 


1.02362 


.976921 


40 






30 


.216440 


4.6202263 


.221695 


4.5107085 


1.02428 


.976296 


30 






40 


.219279 


4.5604080 


.224748 


4.4494181 


1.02494 


.975662 


20 






50 


.222116 


4.5021565 


.227806 


4.3890940 


1.02562 


.975020 


10 


77 





/ 


Cosine 


Secant 


Cotangent 


Tangent 


Cosecant 


Sine 


' 


o 



For functions from 77° 10' to 83° 30' read from bottom of table upward. 

Digitized by LiOOQ LC 



SINES, COSECANTS, TANGENTS, ETC. 45 

Natural Sines, Cosecants, Tangents, etc. — Continued 



o 


i 


Sine 


Cosecant 


Tangent 


Cotangent 


Secant 


Cosine 


' 


o 


13 





.224051 


4.4454115 


.230868 


4.3314759 


1.02630 


.974370 





77 




10 


.227784 


4.3901158 


.233934 


4.2747066 


1.02700 


.973712 


50 






20 


.230616 


4.3362150 


.237004 


4.2193318 


1.02770 


.973045 


40 






30 


.233445 


4.2836576 


.240079 


4.1652998 


1.02842 


.972370 


30 






40 


.236273 


4.2323943 


.243158 


4.1125614 


1.02914 


.971687 


20 






50 


.236098 


4.1823785 


.246241 


4.0610700 


1.02987 


.970995 


10 




14 





.241022 


4.1335655 


.249328 


4.0107809 


1.03061 


.970296 





76 




10 


.244743 


4.0859130 


.252420 


3.9616518 


1.03137 


.969588 


50 






20 


.247563 


4.0393804 


.255517 


3.9136420 


1.03213 


.968872 


40 






30 


.250380 


3.9939292 


.258618 


3.8667131 


1.03290 


.968148 


30 






40 


.253195 


3.9495224 


.261723 


3.8208281 


1.03363 


.967415 


20 






50 


.256008 


3.9061250 


.264834 


3.7759519 


1.03447 


.966675 


10 




15 





.258819 


3.8637033 


.267949 


3.7320508 


1.03528 


.965926 





75 




10 


.261628 


3.8222251 ' 


.271069 


3.6890927 


1.03609 


.965169 


50 






20 


.264434 


3.7816596 


.274195 


3.6470467 


1.03691 


•.964404 


40 






30 


.267238 


3.7419775 


.277325 


3.6058835 


1.03774 


.963630 


30 






40 


.270040 


3.7031506 


.280460 


3.5655749 


1.03858 


.962849 


20 






50 


.272840 


3.6651518 


.283600 


3.5260938 


1.03944 


.962059 


10 




16 





.275637 


3.6279553 


.286745 


3.4874144 


1.04030 


.961262 





74 




10 


.278432 


3.5915363 


.289896 


3.4495120 


1.04117 


.960456 


50 






20 


.281225 


3.5558710 


.293052 


3.4123626 


1.04206 


.959642 


40 






30 


.284015 


3.5209365 


.296214 


3.3759434 


1.04295 


.958820 


30 






40 


.286803 


3.4867110 


.299380 


3.3402325 


1.04385 


.957990 


20 






50 


.289589 


3.4531735 


.302553 


3.3052091 


1.04477 


.957151 


10 




17 





.292372 


3.4203036 


.305731 


3.2708526 


1.04569 


,956305 





78 




10 


.295152 


3.3880820 


.308914 


3.2371438 


1.04663 


.955450 


50 






20 


.297930 


3.3564900 


.312104 


3.2040638 


1.04757 


.954588 


40 






30 


.300706 


3.3255095 


.315299 


3.1715948 


1.04853 


.953717 


30 






40 


.303479 


3.2951234 


.318500 


3.1397194 


1.04950 


.952838 


20 






50 


.306249 


3.2653149 


.321707 


3.1084210 


1.05047 


.951951 


10 




18 





.309017 


3.2360680 


.324920 


3.0776835 


1.05146 


.951057 





72 




10 


.311782 


3.2073673 


.328139 


3.0474915 


1.05246 


.950154 


50 






20 


.314545 


3.1791978 


.331364 


3.0178301 


1.05347 


.949243 


40 






30 


.317305 


3.1515453 


.334595 


2.9886850 


1.05449 


.948324 


30 






40 


.320062 


3.1243959 


.337833 


2.9600422 


1.05552 


.947397 


20 






50 


.322816 


3.0977363 


.341077 


2.9318885 


1.05657 


.946462 


10 




19 


o' 


.325568 


3.0715535 


.344328 


2.9042109 


1.05762 


.945519 





71 




10 


.328317 


3.0458352 


.347585 


2.8769970 


1.05869 


.944568 


40 






20 


.331063 


3.0205693 


.350848 


2.8502349 


1.05976 


.943609 


40 


70 


e 


/ 


Cosine 


Secant 


Cotangent 


Tangent 


Cosecant 


Sine 


/ 






For functions from 70° 40' to 77° 0' read from bottom of table upward. 



Digiti 



zed by G00gk 



46 WEIGHTS AND MEASURES 

Natural Sines, Cosecants, Tangents, etc. — Continued 



• 


/ 


Sine 


Cosecant 


Tangent 


Cotangent 


Secant 


Cosine 


' 


o 


19 


30 


.333807 


2.9957443 


.354119 


2.8239129 


1.06085 


.942641 


30 






40 


.336547 


2.9713490 


.357396 


2.7980198 


1.06195 


.941666 


20 






50 


.339285 


2.9473724 


.360680 


2.7725448 


1.06306 


.940684 


10 




20 





.342020 


2.9238044 


.363970 


2.7474774 


1.06418 


.939693 





70 




10 


.344752 


2.9006346 


.367268 


2.7228076 


1.06531 


.938694 


50 






20 


.347481 


2.8778532 


.370573 


2.6985254 


1.06645 


.937687 


40 






30 


.350207 


2.8554510 


.373885 


2.6746215 


1.06761 


.936672 


30 






40 


.352931 


2.8334185 


.377204 


2.6510867 


1.06878 


.935650 


20 






50 


.355651 


2.8117471 


.380530 


2.6279121 


1.06995 


.934619 


10 




21 





.358368 


2.7904281 


.383864 


2.6050891 


1.07115 


.933580 





00 




10 


.361082 


2.7694532 


.387205 


2.5826094 


1.07235 


.932534 


50 






20 


.363793 


2.7488144 


.390554 


2.5604649 


1.07356 


.931480 


40 






30 


.366501 


2.7285038 


.393911 


2.5386479 


1.07479 


.930418 


30 






40, 


.369206 
.371908 


2.7085139 


.397275 


2.5171507 


1.07602 


.929348 


20 






50 


2.6888374 


.400647 


2.4959661 


1.07727 


.928270 


10 




22 





.374607 


2.6694672 


.404026 


2.4750869 


1.07853 


.927184 





08 




10 


.377302 


2.6503962 


.407414 


2.4545061 


1.07981 


.926090 


50 






20 


.379994 


2.6316180 


.410810 


2.4342172 


1.08109 


.924989 


40 






30 


.382683 


2.6131259 


.414214 


2.4142136 


1.08239 


.923880 


30 






40 


.385369 


2.5949137 


.417626 


2.3944889 


1.08370 


.922762 


20 






50 


.388052 


2.5769753 


.421046 


2.3750372 


1.08503 


.921638 


10 




23 





.390731 


2.5593047 


.424475 


2.3558524 


1.08636 


920505 





07 




10 


.393407 


2.5418961 


.427912 


2.3369287 


1.08771 


.919364 


50 






20 


.396080 


2.5247440 


.431358 


2.3182606 


1.08907 


.918216 


40 






30 


.398749 


2.5078428 


.434812 


2.2998425 


1.09044 


.917060 


30 






40 


.401415 


2.4911874 


.438276 


2.2816693 


1.09183 


.915896 


20 






50 


.404078 


2.4747726 


.441748 


2.2637357 


1.09323 


.914725 


10 




24 





.406737 


2.4585933 


.445229 


2.2460368 


1.09464 


.913545 





00 




10 


.409392 


2.4426448 


.448719 


2.2285676 


1.09606 


.912358 


50 






20 


.412045 


2.4269222 


.452218 


2.2113234 


1.09750 


.911164 


40 






30 


.414693 


2.4114210 


.455726 


2.1942997 


1.09895 


.909961 


30 






40 


.417338 


2.3961367 


.459244 


2.1774920 


1.10041 


.908751 


20 






50 


.419980 


2.3810650 


.462771 


2.1608958 


1.10189 


.907533 


10 




25 





.422618 


2.3662016 


.466308 


2.1445069 


1.10338 


.906308 





05 




10 


.425253 


2.3515424 


.469854 


2.1283213 


1.10488 


.905075 


50 






20 


.427884 


2.3370833 


.473410 


2 1123348 


1.10640 


.903834 


40 






30 


.430511 


2.3228205 


.476976 


2.0965436 


1.10793 


.902585 


30 






40 


.433135 


2.3087501 


.480551 


2.0809438 


1.10947 


.901329 


20 






50 


.435755 


2.2948685 


.484137 


2.0655318 


1.11103 


.900065 


10 


04 


e 


' 


Cosine 


Secant 


Cotangent 


Tangent 


Cosecant 


Sine 


• 


e 



For functions from 64° 10' to 70* 30' read from bottom of table upward. 



Digiti 



zed by G00gk 



SINES, COSECANTS, TANGENTS, ETC. 47 

Natural Sines, Cosecants, Tangents, etc. — Continued 



• 


/ 


Sine 


Cosecant 


Tangent 


Cotangent 


Secant 


Cosine 


' 


• 


26 





.438371 


2.2811720 


.487793 


2.0503038 


1.11260 


.898794 





64 




10 


.440984 


2.2676571 


.491339 


2.0352565 


1.11419 


.897515 


50 






20 


.443593 


2.2543204 


.494955 


2.0203862 


1.11579 


.896229 


40 






30 


.446198 


2.2411585 


.498582 


2.0056897 


1.11740 


.894934 


30 






40 


.448799 


2.2281681 


.502219 


1.9911637 


1.11903 


.893633 


20 






50 


.451397 


2.2153460 


.505867 


1.9768050 


1.12067 


.892323 


10 




27 





.453990 


2.2026893 


.509525 


1.9626105 


1.12233 


.891007 





63 




10 


.456580 


2.1901947 


.513195 


1.9485772 


1.12400 


.889682 


50 






20 


.459166 


2.1778595 


.516876 


1.9347020 


1.12568 


.888350 


40 






30 


.461749 


2.1656806 


.520567 


1.9209821 


1.12738 


.887011 


30 






40 


.464327 


2.1536553 


.524270 


1.9074147 


1.12910 


.885664 


20 






50 


.466901 


2.1417808 


.527984 


1.8939971 


1.13083 


.884309 


10 




28 





.469472 


2.1300545 


.531709 


1.8807265 


1.13257 


.882948 





62 




10 


.472038 


2.1184737 


.535547 


1.8676003 


1.13433 


.881578 


50 






20 


.474600 


2.1070359 


.539195 


1.8546159 


1.13610 


.880201 


40 






30 


.477159 


2.0957385 


.542956 


1.8417409 


1.13789 


.878817 


30 






40 


.479713 


2.0845792 


.546728 


1.8290628 


1.13970 


.877425 


20 






50 


.482263 


2.0735556 


.550515 


1.8164892 


1.14152 


.876026 


10 




29 





.484810 


2.0626653 


.554309 


1.8040478 


1.14335 


.874620 





61 




10 


.487352 


2.0519061 


.558118 


1.7917362 


1.14521 


.873206 


50 






20 


.489890 


2.0412757 


.561939 


1.7795524 


1.14707 


.871784 


40 






30 


.492424 


2.0307720 


.565773 


1.7674940 


1.14896 


.870356 


30 






40 


.494953 


2.0203929 


.569619 


1.7555590 


1.15085 


.868920 


20 






50 


.497479 


2.0101362 


.573478 


1.7437453 


1.15277 


.867476 


10 




30 





.500000 


2.0000000 


.577350 


1.7320508 


1.15470 


.866025 





60 




10 


.502517 


1.9899822 


.581235 


1.7204736 


1.15665 


.864567 


50 






20 


.505030 


1.9800810 


.585134 


1.7090116 


1.15861 


.863102 


40 






30 


.507538 


1.9702944 


.589045 


1.6976631 


1.16059 


.861629 


30 






40 


.510043 


1.9606206 


.592970 


1.6864261 


1.16259 


.860149 


20 






50 


.512543 


1.9510577 


.596908 


1.6752988 


1.16460 


.858662 


10 




31 





.515038 


1.9416040 


.600861 


1.6642795 


1.16663 


.857167 





59 




10 


.517529 


1.9322578 


.604827 


1.6533663 


1.16868 


.855665 


50 






20 


.520016 


1.9230173 


.608807 


1.6425576 


1.17075 


.854156 


40 






30 


.522499 


1.9138809 


.612801 


1.6318517 


1.17283 


.852640 


30 






40 


.524977 


1.9048469 


.616809 


1.6212469 


1.17493 


.851117 


20 






50 


.527450 


1.8959138 


.620832 


1.6107417 


1.17704 


.849586 


10 




32 





.529919 


1.8870799 


.624869 


1.6003345 


1.17918 


.848048 





58 




10 


.532384 


1.8783438 


.628921 


1.5900238 


1.18133 


.846503 


50 






20 


.534844 


1.8697040 


.632988 


1.5798079 


1.18350 


.844951 


40 


57 


e 


t 


Cosine 


Secant 


Cotangent 


Tangent 


Cosecant 


Sine 


' 


o 



For functions from 57° 40' to 64° 0' read from bottom of table upward. 

Digitized by VJiOOQLC 



48 WEIGHTS AND MEASURES 

Natural Sines, Cosecants, Tangents, etc. — Continued 



• 


' 


Sine 


Cosecant 


Tangent 


Cotangent 


Secant 


Cosine 


' 


o 


32 


30 


.537300 


1.8611590 


.637079 


1.5696856 


1.18569 


.843391 


30 






40 


.539751 


1.8527073 


.641167 


1.5596552 


1.18790 


.841825 


20 






50 


.542197 


1.8443476 


.645280 


1.5497155 


1.19012 


.840251 


10 




33 





.544639 


1.8360785 


.649408 


1.5398650 


1.19236 


.838671 





57 




10 


.547076 


1.8278985 


.653531 


1.5301025 


1.19463 


.837083 


50 






20 


.549509 


1.8198065 


.657710 


1.5204261 


1.19691 


.835488 


40 






30 


.551937 


1.8118010 


.661886 


1.6108352 


1.19920 


.833886 


30 






40 


.554360 


1.8038809 


.666077 


1.5013282 


1.20152 


.832277 


20 






50 


.556779 


1.7960449 


.670285 


1.4919039 


1.20386 


.830661 


10 




34 





.559193 


1.7882916 


.674509 


1.4825610 


1.20622 


.829038 





56 




10 


.561602 


1.7806201 


.678749 


1.4732983 


1.20859 


.827407 


50 






20 


.564007 


1.7730290 


.683007 


1.4641147 


1.21099 


.825770 


40 






30 


.566406 


1.7655173 


.687281 


1.4550090 


1.21341 


.824126 


30 






40 


.568801 


1.7580837 


.691573 


1.4459801 


1.21584 


.822475 


20 






50 


.571191 


1.7507273 


.695881 


1.4370268 


1.21830 


.820817 


10 




35 





.673576 


1.7434468 


.700208 


1.4281480 


1.22077 


.819152 





55 




10 


.575957 


1.7362413 


.704552 


1.4193427 


1.22327 


.817480 


50 






20 


.578332 


1.7291096 


.708913 


1.4106098 


1.22579 


.815801 


40 






30 


.580703 


1.7220508 


.713293 


1.4019483 


1.22833 


.814116 


30 






40 


.583069 


1.7150639 


.717691 


1.3933571 


1.23089 


.812423 


20 






50 


.585429 


1.7081478 


.722108 


1.3848355 


1.23347 


.810723 


10 




36 





.587785 


1.7013016 


.726643 


1.3763810 


1.23607 


.809017 





54 




10 


.590136 


1.6945244 


.730996 


1.3679959 


1.23869 


.807304 


50 






20 


.592482 


1.6878151 


.735469 


1.3596764 


1.24134 


.805584 


40 






30 


.594823 


1.6811730 


.739961 


1.3514224 


1.24400 


.803857 


30 






40 


.597159 


1.6745970 


.744472 


1.3432331 


1.24669 


.802123 


20 






50 


.599489 


1.6680864 


.749003 


1.3351075 


1.24940 


.800383 


10 




37 





.601815 


1.6616401 


.753554 


1.3270448 


1.25214 


.798636 





53 




10 


.604136 


1.6552575 


.758125 


1.3190441 


1.25489 


.796882 


50 






20 


.606451 


1.6489376 


.762716 


1.3111046 


1.25767 


.795121 


40 






30 


.608761 


1.6426796 


.767627 


1.3032254 


1.26047 


.793353 


30 






40 


.611067 


1.6364828 


.771959 


1.2954057 


1.26330 


.791579 


20 






50 


.613367 


1.6303462 


.776612 


1.2876447 


1.26615 


.789798 


10 




38 





.615661 


1.6242692 


.781286 


1.2799416 


1.26902 


.788011 





52 




10 


.617951 


1.6182510 


.785981 


1.2*722957 


1.27191 


.786217 


50 






20 


.620235 


1.6122908 


.790698 


1.2647062 


1.27483 


.784416 


40 






30 


.622515 


1.6063879 


.795436 


1.2571723 


1.27778 


.782608 


30 






40 


.624789 


1.6005416 


.800196 


1.2496933 


1.28075 


.780794 


20 






50 


.627057 


1.5947511 


.804080 


1.2422685 


1.28374 


.778973 


10 


51 


e 


$ 


Cosine 


Secant 


Cotangent 


Tangent 


Cosecant 


Sine 


$ 


e 



For functions from 51° 10' to 57° 30' read from bottom of table upward. 

Digitized by VJiOOQLC 



SINES, COSECANTS, TANGENTS, ETC. 49 

Natural Sines, Cosecants, Tangents, etc. — Continued 



e 


/ 


Sine 


Cosecant 


Tangent 


Cotangent 


Secant 


Cosine 1 ' 


« 


30 





.829320 


1.5890157 


.809784 


1.2348072 


1.28676 


.777146 





51 




10 


.631578 


1.5833318 


.814612 


1.2275786 


1.28980 


.775312 


50 






20 


.633831 


1.5777077 


.819463 


1.2203121 


1.29287 


.773472 


40 






30 


.636078 


1.5721337 


.824336 


1.2130970 


1.29597 


.771625 


30 






40 


.638320 


1.5666121 


.829234 


1.2059327 


1.29909 


.769771 


20 






50 


.640557 


1.5611424 


.834155 


1.1988184 


1.30223 


.767911 


10 




40 





.642788 


1.5557238 


.839100 


1.1917536 


1.30541 


.766044 





50 




10 


.645013 


1.5503558 


.844069 


1.1847376 


1.30861 


.764171 


50 






20 


.647233 


1.5450378 


.849062 


1.1777698 


1.31183 


.762292 


40 






30 


.640448 


1.5397690 


.854081 


1.1708496 


1.31509 


.760406 


30 






40 


.651657 


1.5345491 


.859124 


1.1639763 


1.31837 


.758514 


20 






50 


.653861 


1.5293773 


.864193 


1.1571495 


1.32168 


.756615 


10 




41 





.656050 


1.5242531 


.869287 


1.1503684 


1.32501 


.754710 





40 




10 


.658252 


1.5191759 


.874407 


1.1436326 


1.32838 


.752798 


50 






20 


.660439 


1.5141452 


.879553 


1.1369414 


1.33177 


.750880 


40 






30 


.662620 


1.5091605 


'.884725 


1.1302944 


1.33519 


.748956 


30 






40 


.664796 


1.5042211 


.889924 


1.1236909 


1.33864 


.747025 


20 






50 


.666966 


1.4993267 


.895151 


1.1171305 


1.34212 


.745088 


10 




42 





.669131 


1.4944765 


.900404 


1.1106125 


1.34563 


743145 





48 




10 


.671289 


1.4896703 


.905685 


1.1041365 


1.34917 


.741195 


50 






20 


.673443 


1.4849073 


.910994 


1.0977020 


1.35274 


.739239 


40 






30 


.675590 


1.4801872 


.916331 


1.0913085 


1.35634 


.737277 


30 






40 


.677732 


1.4755095 


.921697 


1.0849554 


1.35997 


.735309 


20 






50 


.679868 


1.4708736 


.927091 


1.0786423 


1.36363 


.733335 


10 




43 





.681998 


1.4662792 


.932515 


1.0723687 


1.36733 


.731354 





47 




10 


.684123 


1.4617257 


.937968 


1.0661341 


1.37105 


.729367 


50 






20 


.686242 


1.4572127 


.943451 


1.0599381 


1.37481 


.727374 


40 






30 


.688355 


1.4527397 


.948965 


1.0537801 


1.37860 


.725374 


30 






40 


.690462 


1.4483063 


.954508 


1.0476598 


1.38242 


.723369 


20 






50 


.692563 


1.4439120 


.960083 


1.0415767 


1.38628 


.721357 


10 




44 





.694658 


1.4395565 


.965689 


1.0355303 


1.39016 


.719340 





46 




10 


.696748 


1.4352393 


.971326 


1.0295203 


1.39409 


.717316 


50 






20 


.698832 


1.4309602 


.976996 


1.0235461 


1.39804 


.715286 


40 






30 


.700909 


1.4267182 


.982697 


1.0176074 


1.40203 


.713251 


30 






40 


.702981 


1.4225134 


.988432 


1.0117088 


1.40606 


.711209 


20 






50 


.705047 


1.4183454 


.994199 


1.0058348 


1.41012 


.709161 


10 




45 





.707107 


1.4142136 


1.000000 


1.0000000 


1.41421 


.707107 





45 


• 


* 


Cosine 


Secant 


Cotangent 


Tangent 


Cosecant 


Sine 


• 


« 



For functions from 45° 0' to 51° 0' read from bottom of table upward. 



Digiti 



zed by G00gk 



60 



WEIGHTS AND MEASURES 



Moment of Inertia, Radius op Gyration and Center op Gravity 

Moment of Inertia. — The moment of inertia of a section is the 
sum of the products of each elementary area of the section times the 
Square of its distance from an axis through the center of gravity 
of the section or other axis assumed for purposes of computation. 
Thus suppose an area A be divided into a large number of small 
areas a, and that each has its own radius r, from the assumed axis, 
then the moment of inertia / — ^ a r 2 . See table on page 52. 

Radius of Gyration. — This is equal to the square root of the 
quotient of the moment of inertia divided by the area of the section, 

expressed, R — A/ I /A. The radius of gyration is used in column 

calculations. The unbraced length of the section divided by the radius 
of gyration is termed the ratio of slenderness. See Columns. 

Center of Gravity of a body is that point about which, if sus- 
pended, all the parts would be in equilibrium, that is, there would 
be no tendency to rotate. If a body is suspended at its center 
of gravity, it will be in equilibrium in all positions. If it is sus- 
pended at any other point it will swing into a position such that 
its center of gravity is vertically below its point of suspension. 

To Find the Center of Gravity of a Cross Section of a Ship. — 
First find the moment of the area about an end ordinate by taking 
each ordinate and multiplying it by its distance from the end 
ordinate. These products put through Simpson's rule will give the 
moment of the figure about the end ordinate, which moment divided 
by the area will give the distance of the center of gravity of the 
area from the end ordinate. 



Example. A section of a steamer has half breadths beginning at the load water 
line, 4.86, 4.20, 3.40, 2.42, 1 .33, .70 and .10 ft. spaced 2 ft. apart. Find how 
far from the load water line the center of gravity of the section is. 



Number 
of 


Length 


Simpson's 
Multi- 


Function 
of 


Number of 
Intervals 


Products 
for 


Ordinate 


Ordinate 


pliers 


Ordinates 


from No. 1 


Moments 


1 


4.86 


1 


4.86 





.00 


2 


4.20 


4 


16.80 


1 


16.80 


3 


3.40 


2 


6.80 


2 


13.60 


4 


2.42 


4 


9.68 


3 


29.04 


5 


1.33 


2 


2.66 


4 


10.64 


6 


.70 


4 


2.80 


5 


14.00 


7 


.10 


1 


1.00 


6 


6.00 




44.60 


90.08 



Digitized 



by Google 



CENTER OF GRAVITY 



51 



Half area from load water line = X X 2 X 44 . 60. 

Moment of half area about load water line = X X 2 X 2 X 90.08. 

Distance center of gravity of section below load water line 



X X 2 X 2 X 90.08 



» 4.03 ft. 



HX2 X44.60 
If the total area or total moment was desired multiply by 2. 

To Find the Center of Gravity of a Water Plane from its Middle 
Ordinate. — Lay off a table thus: 



Number of 
Ordinate 


Length of 
Ordinate 


Simpson's 
Multipliers 


Functions of 
Ordinates 


Number of 

Intervals 

from Middle 

Ordinate 


Products for 
Moments 


1 

. IX 
2 
3 
4 
5 


.10 
2.48 
4.86 
8.75 
11.16 
12.12 

12.25 

12.25 
11.92 
11.12 
9.10 
6.80 
3.90 


X 
2 

IX 
4 
2 
4 

2 

4 

2 

4 

IX 

2 

X 


.05 

4.96 

7.29 

35.00 

22.32 

48.48 

24.50 

49.00 
23.84 
44.48 
13.65 
13.60, 
1.95 


5 

*X 

4 

3 

2 

1 



1 

2 

3 

4 

4H 

5 


.25 
22.32 
29.16 
105.00 
44.64 
48.48. 


6 


249.85 


7 

8 

9 

10 

n 


49.00 
47.68 
133.44 
54.60 
61.20 
9.75 


. 


289.12 


355.67 



Ordinates 9.5 ft. apart 

355.67 -249.85 - 105.82 
Distance center of gravity aft of the middle ordinate 

105.82 X9.5 



289.12 



= 3.47 ft. 



Or let 

A = sum of functions of ordinates 

B — sum of products of moments forward of the middle ordinate 

C = sum of products of moments aft of the middle ordinate 

subtract~the smaller sum of products of moments from the larger 

and let the difference be D. 

I Then the distance of the center of gravity from the middle ordinate 
_ D X distance the ordinates are apart 
A 

and whether the distance is forward or aft depends on whether B 

or C is the largest. 

Digitized by VjiOOQLC 



52 



WEIGHTS AND MEASURES 
Properties of Various Sections 



Sections 



Area of Section 
A 



Distance from Neutral 

Axis to Extremities 

of Section 

x and xi 



— *-Hfr 



T 






T 

1 



a 



-I 

1 



£ 



hfrgH 



»»-«i> 



T 




a = -7z=.70Ta 



y Google 



PROPERTIES OF VARIOUS SECTIONS 53 

Properties of Various Sections — Continued 



Moment of Inertia 
1 


Section Modulus 

XI 


Radius of Gyration 


a* 

12 


a» 
• 


JL-=.2Wa 
Vl2 


** 
3 


a» 

3 


'*-"*. 




a«-*« 

fia 




12 


. , f*F. 


12 


r-^==.118a« 
6 V 2 


-4==. 280a 
V12 

- uigiiizsucirvjOOS? 



54 WEIGHTS AND MEASURES 

Properties of Various Sections — Continued 



Sections 



£ 



T 

1 



Area of Section 
A 



bd 



Distance from Neutral 
Axis to L 
, of Section 
x and ii 




bd 



» = d 



Y-& 



V 

1 







6d-bidi 



i 




bd 



d 



bd 



Vb» + d» 



y Google 



PROPERTIES OF VARIOUS SECTIONS 55 

Properties of Various Sections — Continued 



Moment of Inertia 
I 


Section Modulus 
8--L 


Radius of Gyration 


12 


fad> 
6 


-7==.280d 
V12 


fa* 
3 


fad> 
3 

1 • 


\/3 




i 

b#-Wdi» 
6d 


- 


bd«-bidi« 
12 


/ b#-bidi' 

y 12 (bd - udi) 


fatf 


\ ! 
; ' i 

i b»d« 


bd 


6(b» + d») 


i 6Vb»-fd« 5 


V 6 (b» + d J ) 



y Google 



66 WEIGHTS AND MEASURES 

Properties op Various Sections — Continued 



Sections 



Area of Section 
A 





bd 



M 
2 



Distance from Neutral 

Axis to Extremities 

of Section 

xandxt 



dcosa-4-bsun 



d 



2d 
* = F 




bd 
2 



* = d 




i=.w# 



x »"-o 



y Google 



^ 



PROPERTIES OF VARIOUS SECTIONS 57 

Properties op Various Suctions — Continued 



Moment of Inertia 

I 



~(d»ecrfa + b«Bin««) 



Section Modulus 
8 = 1 



db/ d»coe» 
6 V dooft 



» + b ana ; 



Radius of Gyration 



-A 



/■ 



' d» cqb» a + b» an* a 
12 



36 



b# 
34 



Vl8 



= .236d 



b# 
12 



12 



vr 



>.408d 



^=.049* 



-w= [ 



<XWd» 







by Goog le 



58 WEIGHTS AND MEASURES 

Properties of Various Sections— Continued 



Sections 






W—6 M 



Area of Section 
A 



»r(d»-di») 




= .785(d*-di») 



8 " 



Distance from Neutral 

Axis to Extremities 

of Section 

x and xi 



«-!*-■«" 



i = ^ L -4 L d =>288d 



b + bi 



. d 



-|d"tan.30°=.866d« 



b + 2bi d^ 
s b + bi *3 

bi + 2b ^ 
= b + bi *3 



Digitized by VJ \J\J V LV^ 



PROPERTIES OF VARIOUS SECTIONS 59 

Properties op Various Sections — Continued 



i 



Moment of Inertia 



r (»-&«) 
64 



= M9(&-&x<) 



frr*-64 
1152v ' 



d>s.007d> 



b» + 4bh + bi» 

36(b + b») ' 



A r d»(l + 2coB«30 o )1 
12 I 4cos*30* J 



= .06d« 



Section Moadulus 



S-I 



32 d "- 098 d 



frr»-64 
102 (3» - 4) 



. d>=.024d» 



b» + 4bb» + hi* 
12 (bi + 2b) 



. d* 



A. r d(l + 2cos»30°) ] 
6 I 4 co* 30° J 



= .12d» 



Radius of Gyration 



Vd» + df 

4 



V r »r«~64 



12fT 



. d=.132d 



6(b+bi)y 



2(b* + 4bbi + bi«) 



4 ops 30* Y 



2 coe» 30° 
3 



= .2Md 



y Google 



60 



WEIGHTS AND MEASURES. 
Properties of Various Sections — Continued 



Area of Section 
A 



Distance from Neutral 

Axia to Extremities 

of Section 

x and zi 




|-d»tan.30°=-.8fl6d* 



= 2^W= 577d 



/T\ 



2d»tnn.22* , = .828d» 



i 



z 




^=.785 bd 



»"?T 



y Google 



PROPERTIES OF VARIOUS SECTIONS 61 

Properties of Various Sections — Continued 



Moment of Inertia 

I 



a rd»(i + 2<x»>ao*) i 

12 L 4 corf 30° J 



- .06* 



8ection Modulus 
8 = 1 



A. rd(t + 2ocW30*)1 
6 L 4cos30° J 



= .104d» 



Radius of Gyration 



-«4 



d / l + 2 coB» 30° 

4 cob 80° y 3 



= .264d 



A, rd»(l + 2oos«22n '| 
12 L 4cos»22*° J 



= .055d* 



A r d (1 +-2 ooa* 22m 

6 L 4ooB22i* J 

= .10W» 



4oos22i 



/1JH200 
• V 3 

= .257d 



eoe»22i B 



vbd> 
04 



>bd« 
32 



= .098bd» 



j i y i u^uyCoOgl e 



62 WEIGHTS AND MEASURES 

Properties of Various Sections — Continued 



Sections 






Area of Section 
A 



td + 2b' (s + nO 



Distance from Neutral 

Axis to Extremities 

of Section 

x and xi 



d 




td + 2b' (a + nO 




td + b' (a + nO 



Digitized by VJ vJvJ V LV^ 



PROPERTIES OF VARIOUS SECTIONS 63 

Properties of Various Sections — Continued 



Moment of Inertia 

I 


Second Modulus 

s.I 

zt 


Radius of Gyration 

-A 


£[„*_£*_„] 


21 
d 


-A 


i[b»(d-M + W 
+ i(b.-f)] 


21 
b 


•ys_ ■ 


![!*-£*.-»] 


1 

21 
d 


■ .-/?'• 



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64 



WEIGHTS AND MEASURES 
Properties of Various Sections — Continued 



Sections 




*££ 



13 



^ 

& 



i 



1" 






■* u — r 

I- — </■ 



ILfc 



Area of Section 
A 



td + b'(a + nO 



bd - h (b - t) 



bd - h (b - t) 



Distance from Neutral 

Axis to Extremities 

of Section 

x and xi 



x = [b% + ^+.f (b-t)»| 

(b + 2t)] 4- A I 

xi = b — x 



-4 



Digitized by 



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PROPERTIES OF VARIOUS SECTIONS 65 

Properties of Various Sections — Continued 



Moment of Inertia 
I 


Section Moduli* 

XI 


Radius of Gyration 

-VI 


y[2sb» + lt»+!.(b«-t«)] 

-A* 


I 


-vl 


• 


bd» - h> (b - t) 
6d 




bd» - h> (b - t) 
12 


/ M»-h»(b-t) 

y i2[bd-h(b-t)] 




2sb> + ht* 
6b 




2sb> + bt* 
12 


/ 2sb» + ht> 
y 12[bd-h(b-t)] 



66 WEIGHTS AND MEASURES 

Properties op Various Sections — Continued 



Sections 



K^ 



1 



ls> 



JL 



<*» 






* 






-j 



Area of Section 
A 



bd - n (b - t) 



bd-h(b-t) 



Distance from Neutral 

Axis to Extremities 

of Section 

x and xi 



d 



_ 2b*i + W 
X "~ 2A 
xi = b — x 




td + s (b - t) 



Digitized by Vji\J vJ V LV^ 



PROPERTIES OF VARIOUS SECTIONS 67 

Properties op Various Sections — Continued 



Moment of Inertia 
I 



bd» - h» (b - t) 
12 



2sb» + ht» 



- Ax« 



td» + a» 0> - t) 
12 



Section Modulus 
8-1 



bd» - h» (b - t) 
6d 



I 
b -x 



td» -f a» (b - t ) r 
6d 



Radius of Gyration 



/ 



bd» - h» (b - t) 
12[bd-h(b-t)l 



v- 



td» + af (b - t) 
12 (td + s (b - t) 1 



y Google 



68 



WEIGHTS AND MEASURES 
Properties of Various Sections — Continued 



Sections 



ta 



i 



a 






Area of Section 
A 



be + ht 



Distance from Neutral 

Axis to Extremities 

of Section 

x and xi 



d»t + s»(b-t) 
X ~ 2A 

n = d — x 






J« "<? >> 



bs + ht + bis 



td« + s«(b-t) + g(bi-t)(2d-B) 
2A 
xi = d — x 




iWH 




bs + 



h (t + 1.) 



3bs> + 3th (d + s) + h (ti - 1) (h + 3s) | 



6A 
xi = d — x 



y Google 



PROPERTIES OF VARIOUS SECTIONS 69 

Properties of Various Sections— Continued 



Moment of Inertia 

I 



to* + bx* - (b - t) (x - b)« 



Section Modulus 
fl-i- 



I 

d- x 



Radius of Gyration 



Vi 



/■ 



to» + bx» - (b - t) (x - g)» 
3(bs + ht) 



bx» + bix,» - (b - t) (x - s)» 



3 

(fa - t) (Xl - 8 )» 

3 



I 

d-x 



bx» -f DM* - (b - t) (x - g)» 
3 (be + ht + bis) 

(fa - t) (xi - 8K | H 
3(be + ht + bi8)J 



4bB» + h»(3t + ti) 
12 



-A(X-8)» 



I 

d -x 



^ 



y Google 



SECTION II 
STRENGTH OF MATERIALS 

Stress is the general term denoting the force or resistance which 
acts between bodies or parts of a body when under the influence 
of a load. It is measured either in tons or lb. per square inch of 
sectional area. 

Strain is the change in form produced by stress. 

Tension. — A body is said to be under tension when the action 
of a force tends to extend it in the direction of its length. Tensile 
strength is the resistance per unit of surface which the molecular 
fibers oppose to separation. 

Compression. — A body is said to be under compression when 
the action of a force tends to compress it in the direction of its 
length. 

Shearing Strain. — A body is said to be subjected to a shearing 
strain in any cross section when the distorting force acts in the 
plane of that cross section. 

Elasticity is the power to resist permanent deformation. The 
elastic limit is the limit of stress that can be withstood without 
permanent elongation. The continued application of a stress in 
excess of the original elastic limit will eventually cause fracture 
owing to fatigue of the material. 

The modulus or coefficient of elasticity is the ratio between the 
stresses and corresponding strains for a given material. If I be the 
strain or increase per unit length of a material subjected to tensile 
stress, and p the unit stress producing the elongation, the modulus 

of elasticity E is equal to -y-. 

Modulus of rupture is the strain at which the molecular fibers 
cease to hold together. 

70 



ULTIMATE STRENGTH 



71 



Ultimate Strength. — The load producing rupture gives the 
strength of a material, .and it is usual to denote the strength by 

the expression ^-r. — . In this expression the original cross 

cross section 

section is taken before it has been decreased by the stress. 

Strength op Materials* 
(Stresses per Square Inch) 



Metals and Alloys 



Streams in Thousands of Pounds 



Ten- 
sion 
Ulti- 



Elastic 
Limit 



Corn- 



Ulti- 
mate 



Bend- 
ing 
UlS- 



ing 
Ulti- 



Modulus 
of Elastic- 
ity. Lb. 



Elong- 
ation 

% 



Al uminum — 

cast 

bars, sheets 

wire annealed 

Aluminum bronze — 

5%toZ^%al 

10% al 

Brass— 

17% zinc 

30% zinc... 

cast, common 

wire annealed 

Bronze — v 

8% tin 

13% tin 

24% tin 

gun metal — 

9% copper, l%tin.. 
manganese, cast — 

10% tin, 2%mang... 
manganese, rolled — 

10%tin,2%mang... 
phosphorus, cast — 

9% tin, l%phos 

phosphorus, wire — 

9% tin, l%phos 

tobin, cast — 
38% zinc, VA% tin, 

HIead 

tobin, rolled — 
38% zinc, 1H% tin, 

Mlead 

Copper — 

cast 

plates, rods, bolts 

wire annealed 

Delta Metal- 
cast f 55-60% copper 
plates! 38-40% zinc 
bars 1 2- 4%iron 
wire I 1- 2%tin 



15 
24-28 
20-35 

75 

85-100 

32.6 

28.1 

18-24 

50 

28.5 
29 4 
22 

25-55 

60 
100 

50 
100 

66 

80 

25 

32-35 

36 

45 

68 
85 
100 



6.5 

12-14 

14 



8.2 



19 
20 
22 

10 

30 

80 

24 



6 
10 
10 



120 



30 



42 
53 
114 



125 



40 
32 



23 
26 
20 



34.5 
32 



22 



12 



30 



11,000,000 



9,000,000 
14,000,000 

10,000,000 



10,000,000 



4,500,000 
10,000,000 

15,666,000 



26.7 
20.7 



5.5 
3.3 



♦Carnegie Steel Co. Handbook 



Digitized 



by Google 



72 



STRENGTH OF MATERIALS 



Strength op Materials — Continued 
(Stresses per Square Inch) 





Stresses in 


Thousands of Pounds 


Modulus 
of Elastic- 
ity, Lb. 




Metals and Alloys 


Ten- 
sion 
Ulti- 
mate 


Elastic 
Limit 


Com- 
pression 
Ulti- 
mate 


Bend- 
ing 
Ulti- 
mate 


Shear- 
ing 
Ulti- 
mate 


Elong- 
ation, 

% 


Gold— 


20 
30 

15-18 
18-24 
27-35 

1.8 

2.2-2.5 

3.3 

53 
32 
40 

58-68 

55-65 
52-62 

55-65 
45-55 

60 
70 
80 

55-70 

85-100 

65-110 

120 

80 

3.5-1.6 

48 
50 

80 
60 

4-6 
7-16 


4 

6 
15-20 

H tens. 

Vt tens, 
^tens. 

J^tens. 
Htens. 

27 
31.5 
36 

33 

55 

50 

40-70 

60 

40 
1.5-1.8 

26 

27 

27' 
4 


80 
46' 

tensile 

tensile 
tensile 

tensile 
tensile 

tensile 
tensile 
tensile 

tensile 

tensile 

tensile 

"6' 

tensile 
tensile 

18 


30 

25-33 

30 

tensile 

tensile 
tensile 

tensile 
tensile 

tensile 
tensile 
tensile 

tensile 

tensile 

tensile 

"4' 

tensile 
tensile 

7 


18-20 
'46' 

% tens. 

^tens. 
% tens. 

%tens. 
%tens. 

%tens. 
%tens. 
\i tens. 

%tens. 

%tens. 

^i tens. 

|tens. 
§ tens. 


8,000,000 
12,000,000 

1,000,000 

1,000,000 

720,000 

29,000,000 

29,000,000 
29,000,000 

29,000,000 
29,000,000 

29,000,000 
29,000,000 
29,000,000 

29,000,000 

29,000,000 

29.000,000 

iooo.'obb 

28,000,000 
28,000,000 

15,000,000 
25,000,000 

13,000,000 








Iron, Cast — 












Lead — 
cast 












Platinum wire — 












Steel— 
Bhip 


25.9- 


boiler — 
fire box 


22.1 
27.3- 


flange plates 

• rivets — 

ships 


23. 
28.8- 
24.2 

27.3- 


boilers 


23. 
27.3- 


castings — 
soft 


23. 

22. 




18. 


hard 


15. 


concrete bars, plain, struc- 
tural grade 

concrete bars cold twisted 

nickel, 3.25% nickel, 

shapes, plates, bars . 

springs, untempered.. . 
wire unannealed. ......' 


25.4- 
20. 
5. 

17.6- 
15. 


Tin, cast 




Wrought Iron — 








wire 

unannealed 

annealed 




Zinc — 
cast 




rolled sheets 
















Die 


itized by V 


jOOQk 





WORKING STRESS 



73 



Strength of Materials — Continued 
(Stresses in Pounds per Square Inch) 





Ultimate Average Stresses 


Modulus 

of 
Elasticity 


Safe Working Stresses 


Building Materials 


Com- 
pression 


Ten- 
sion 


Bend- 
ing 


Com- 
pression 


Bear- 
ing 


Shear- 
ing 


Stone— 
bluestone 


12,000 
12.000 
8,000 
5,000 
10,000 

10,000 
6,000 

30.000 

700 

5,000 

1,700 

1.200 

500 


1,200 

1,200 

800 

150 

3,000 

200 

3,000 
70 


2,500 
1,600 
1,500 
1,200 
5,000 

600 
3,000 


7,000,000 
7,000,000 
7.000,000 
3,000.000 
14,000,000 

8,000,000 


1,200 

1,200 

800 

500 

1,000 

420 
350 
280 
140 
280 
168 


1,200 

1,200 

800 

500 

1,000 

600 
500 
400 
250 
500 
300 


200 


(granite 


200 


limestone — marble.-. . 
sandstone 


150 
150 


slate 


175 


Brick- 
common, good 

pressed and paving. . . 

Masonry — 

granite 

limestone— bluestone . 

sandstone 

nibble 




concrete 1, 2H, 5 

brick, common 

Miscellaneous — 

glass, common 

plaster , 

terracotta , 


:::: 


Concrete — 

1, 2^, 5, hard stone. . 

soft stone 

cinders 


Rxintorced Concrete— Safe Working Stresses 
Elastic Modulus— 
2,000,000 if ultimate compression is up to 2,200. 


1. 2H. 5, means 1 part 
cement, 2\£ sand, 5 
stone 


2J500i000 if ultimate compression is over 2,200. 

3,000,000 if ultimate compression is over 2,900. 
Compression — 

22.5% of ultimate compression on piers or columns of 
lengths not exceeding 12 ins. 
Bearing— 

32.5% of ultimate compression on surfaces of at least 
twice the loaded area. 
Shearing — 

2% of ultimate compression, horizontal bars. 

3% for reinforcement with bent up bars. 

6% for thoroughly reinforced webs. 
Bond— 

4% of ultimate compression for plain bars. 

2% for drawn wire. 



Working Stress: Factor of Safety. — The stress allowed under 
working conditions is only a fraction of the ultimate strength and 
is called the working stress. The factor of safety is that number 
which is divided into the ultimate strength to arrive at the working 

stress. Thus working stress = -= — r-^ — ! e f ~ . The factor of 

factor of safety 

safety depends to a great extent on the nature of the forces acting 

and on the material. 

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BEAMS 

Factors of Safety 



75 



Material 


Steady 
Load 


Load Varying 
from Zero to 

Maximum 
in One 

Direction 


Load Varying 
from Zero to 

Maximum 
in Both 

Directions 


Suddenly 
Varying 

Loads 
and 

Shocks 


Cast iron 


6 
4 
5 
8 
15 
15 


10 
6 
6 
10 
20 
20 


15 
8 
8 
15 
25 
25 


20 


Wrought iron 

Steel 


12 
12 


Wood 


' 20 


Brick 


30 


Stone 


30 







Hemp rope for running rigging factor of safety 8-9 
Steel rope for running rigging factor of safety 6-7 
Steel rope for standing rigging factor of safety 5-6 



Beams 

The strength of a beam depends on the form of its cross section, 
how the load is distributed and on the way the beam is supported. 
In the majority of cases in ship construction beams are fixed at 
both ends, although some fixed at one end occur in fittings as bitts, 
davits, etc. 



+ a- 



iwbi ffdxi cth 



</-> 



«i 



** 



Figure 11 



When a beam is loaded there is always compression in the top- 
most fibers and tension in the bottom. There is a position in the 
cross section at which the fibers are neither in compression nor 
tension, and this position is the neutral axis of the section. Thus 
the neutral axis passes through the center of gravity of every cross 
section and is at right angles to the direction in which the load acts. 



nvJ^v^ 



76 



STRENGTH OF MATERIALS 



The algebraic sum of the moments of the external forces about 
any point in a beam is the bending moment at that point; that is, 
the bending moment at any point is the moment about that point 
of either reaction minus the sum of the moments of the intermediate 
loads about the same point. The bending moments at several points 
on the beam shown in Fig. 11 are: at Wi = Ria, at W% = Ri (a + b) 
- Wi b, at Wz = Ri (a + b + c) - [W* c + Wi (b + c)]. Various 
methods of loading are shown under Bending Moments of Beams. 

Fibers which are at equal distances from the neutral axis will 

be deformed to the same extent. The resistance to bending is the 

combination of the resistances to tension and compression. Thus 

let 

bending moment 

distance from the outermost fiber to the neutral axis 

moment of inertia of the section 

safe or allowable unit fiber stress in pounds per square 

inch 



M 

V 

I 

V - 



Then -^ 



M 



or p 



My 



or M = 



V 
The moment of resistance M x of 



and — the section modulus = a, 

y 

a beam is the sum of the moments about the neutral axis of all the 
stresses in the fibers composing the section. Hence Mi — 8 p; that 
is, the safe resisting moment is equal to the safe fiber stress multi- 
plied by the resistance. 




Figure 12 
The reactions or supporting forces of a beam must equal the 
load on it. If the load on a beam is uniformly distributed, applied 
at the center of the span or symmetrically placed and of equal 
amount on each side of the center, the reactions Ri and Ri will each 
be equal to one half the load. When the load is not symmetrically 
placed, the reactions are found by the principle of moments. 



• 



le 



BEAMS 71 

Suppose a beam as in Fig. 12 is supporting loads Wi, W* and Wi, 
I the span or distance between the reactions Ri and R* t a, b t and c 
the distances from the reaction Ri to the loads W\, W2 and Wi. 

Then the righOhand reaction & = <^X«)+(TT,X 6)+qT.X c). 

Hence to find the reaction at either support, multiply each load by 
its distance from the other support, and divide the sum of these 
products by the distance between supports. Since the sum of the 
reactions must equal the sum of the loads, if one reaction is found 
the other can be obtained by subtracting the known one from the 
sum of the loads. 

The loads and reactions, besides causing bending or. flexure, 
create shearing stresses in the beam by their opposing tendency; 
that is, as the reactions act upward, and the loads downward, 
the effect is to shear the fibers of the beam vertically. At any 
section, the shear is equal to either reaction minus the sum of the 
loads between that reaction and the section considered. The 
maximum shear is always equal to the greatest reaction. For a 
single beam with a uniformly distributed load, the maximum shear 
is at the supports, and is equal to one half the load or the reac- 
tion; the shear changes at every point of the loaded length, the min- 
imum shear being zero at the center of the span. The maximum 
shear in a simple beam having a single load (omitting weight of 
beam) concentrated at the center is equal to one half the load, 
and is uniform throughout the beam. When a beam supports sev- 
eral concentrated loads, changes in the amount of shear occur only 
at the points where the loads are applied. 

Examples. What is the greatest safe load that can be lifted by a boat davit 
having an outreach of 5 ft. and a diameter of 7 ins. The davit is of wrought iron. 

This is a case of a beain with one end fixed and with the load at the other, hence 
the bending moment is M = W X L, where L is the outreach of the davit or 5 ft. 

From the beam formula M = — 

V 

p — safe load for wrought iron = 5 tons 

L « 5 ft. X 12 ins. « 60 ins. 

/ "• 

= section modulus = S 
V 
d ■■ diameter = 7 ins. 



W XL = v X^- 



V 

,*d* 



p X S 5 tons X "32 
Hence W = 2^_ — = — = 2\£ tons. See also formula for 



L 60 

Boat Davit. 



Digitized 



by Google 



78 STRENGTH OF MATERIALS 

Find the safe resisting mpment of a Northern yellow-pine beam 10 ins. wide by 
12 ins. deep, using a factor of safety of 4. 

Here Afi = 8 p. 

The section modulus S (see table) is ~ or 10 X 12 X 12 » 2 40 

o o 

The modulus of rupture for Northern yellow pine is 6,000 lb. 

The desired factor of safety being 4, the safe unit stress p = ~ — — 1,500 lb. 

4 

Substituting these values in the formula, safe resisting moment M\ = 5p, we 
have 1,500 X 240 = 360,000 as the safe resisting moment of the beam section in 
inch pounds. 

[Above paragraph contains abstracts from Building Trade Handbook, Int. School 
of Correspondence.] 

Beams Under Various Loading Conditions 

[From Pocket Companion, Carnegie Steel Co.] 

Bending Moments and Deflections 

Notation in Formulae 

A = area of section in square inches 

y = distance from center line of gravity to extreme fiber in inches 

/ = moment of inertia about center line of gravity in inches* 

8 = section modulus = — in inches 8 
V _ 

r = radius of gyration = if ~a m inches 

/ = bending stress in extreme fiber in pounds per square inch 

E = modulus of elasticity in pounds per square inch 

I = length of section in inches 

d — depth of section in inches 

b =* breadth of section in inches 

t * = thickness of section in inches 

W, Wi, Wi = superimposed loads supported by beam in pounds 

w = superimposed loads in pounds per unit length or area 

W max. = maximum safe load at point given in pounds 

R, 'Ri = reactions at points of support in pounds 

Af, Mi, M% = bending moments at points given in inch pounds 

M max. = maximum bending moment in inch pounds 

D, Di = deflections at points given in inches 

D max. — maximum deflection at point given in inches 

• Digitized by VjiOOQ 1C 



CANTILEVER BEAM 79 

1. Cantilever Beam. — Concentrated load at free end. 




r *v* 



Ri (max. shear) 
M, distance x 
M max. at R\ 

IF max. 
D max. 



W 

Wz 
Wl 



Li 
i 

3E I 



2. Cantilever Beam. — Uniformly distributed load. 

Ri (max. shear) 
M, distances 
IT max. 
D max. 




- W 



Wx* 
21 



2fs 

I 



Wl* 
8E I 



3. Cantilever- Beam. — Load increasing uniformly to fixed end. 

Ri (max. shear) 




M, distances] 
M max. at R\ 
IP max. 
D max. 

Digiti 



w 

Wx* 
30 

Wl 
3 

3/j 
I 

Wl* 
15EI 



zed by GOOgk 



80 STRENGTH OF MATERIALS 

4. Beam Supported at Ends. — Concentrated load near one end. 








R (max. shear if 6 > a) 


Wb 

I 


Ri (max. shear if a > 6) 


_ Wa 

I 


M, distance x 


Wbx 

I 


M max. at point of load 


Wab 
I 


IF max. 


fsl 
ab 


D max. 


= 


Wab(a + 26) V3o (o +26) 



27 E II 

5. Beam Supported at Ends.— ^Concentrated load at center. 




• 
R (max. shear) = Ri 


W 

2 


M, distance x 


Wx 
2 


M max. at point of load 


IF* 
4 ' 


IF max. 


4/8 

I 


D max. 


" 48#7 



6. Beam Supported at Ends. — Two unsymmetrical concentrated 
loads. 

R (max. shear if o < 6) = 




$6 62 



Hi 



M , distance a = Ra = 

Mi max. distance b (6 >a) = /fr6 = 

^ /J _l_ IA 

"2T. 0+«-*> 

IF 
Ma, distance 3=#a; — ■— (3— a) 



TF max. (6 > o) = 



2J/a 



6 (* + a - 6) 

Digitized by VjiOOQ LC 



BEAM SUPPORTED AT ENDS 81 

.7. Beam Supported at Ends. — Two symmetrical loads. 

R (max. shear) = Rx 
^r ' "\. Mm/r* M* distance x 




W 
2 



Wx 

2 



M max. at and between loads 



Wa 
2 



|*0 O^ ' 



W max. 
D max. 

8. Beam Supported at Ends. — Three concentrated loads 



- '** 



-iTWl «"-«') 




t 1 > 



■u 



Wb + Wtbi + Wtb* 
I 



10 




** 



Rx « Wa + Wl ai + ^ a> 

3f at W = Ra 

M max. if TF = or > J2 

Af at TFi = ftoi - TT(oi - a) 

Af max. ifJFi + TF = ffor > ft 
Af max. if Wx + TT« = ft, or > ft, 

Af at TPj = fta* - W (at - a) - 
Wx (jot - ax) 
M max. if JFa = ft, or > ft 



9. Beam Supported at Ends.— Uniformly distributed load, 




w 

R (max shear) - Rx = ~- 



M, distance x 



-?0-f) 



Af max. at center = 
IF max. 
Z> max. 



8 

8 fa 

I 

6WP 



384J57 J 

Digitized by VjOOQLC 



82 



STRENGTH OF MATERIALS 



10. Beam Supported at Ends. — Load increasing uniformly to one 
end. 



2W 

Rt (max. shear) — — ^~ 




M, distance x 



Wx/ _xf\ 
- 3 V 1 l) 



x* a- * *V3 2 Wl 

M max. distance — - — — — ■=. 



TPmax. 
D max. 



9V3 
27 fa 
2W3* 
.013044 WP 
EI 



11. Beam Supported at Ends. — Load decreasing uniformly to 
center. 




R (max. shear) = R\ 
M, distance x 



W 
2 



w /l x , 2x*\ 



M max. distance i 
IF max. 
D max. 



IFJ 
12 

12/8 

I 
3 TTP 
320^7 



12. Beam Supported at Ends. — Load increasing uniformly to 
center. 




R (max. shear) = Ri 
M, distance x = 
M max. distance \ 
Wmax. 
D max. 



W 
2 



^•(i-£) 



TfJ 



6/a 



Digitized 



byGoOgl 



60^7 



BEAM SUPPORTED AT ENDS 



83 



13. Beam Supported at Ends. — Uniform load partially distributed. 

R (max. shear if a < c) = 

W (2c 4- b) 

21 
W (2a + b) 
2L 
M, distance x — a or <a = Rx 




Ri 



Mi, distance x > a 



■■ Rx - 



W(x - o)» 
26 



^ x zp ^ 



Jfj, distance x > (a + b) *= 

_ TF (2x - 2a - b) 
** 2 

Jf max. distance o + -= = 
W (2c + b) [4«i + b (2c + b)] 



IF max. 



8ft /g 



(2c + 6) \4al + b (2c + b)] 

14. Beam Supported at Ends. — Uniform load partially discon- 



tinuous. 




u-4-/ 



# (max. shear if W > Wi) = 

W (21 - a) +Wic 

21 
Wi (21 - c) + Wa 



Ri 



21 



M, distance x < a = R x r — 

Mi, distance x > a — 



Rx - 



W(2x -a) 



M max. distance x ■» 

2 TFo/ - Fa* + Wi Ca 



2 WI 



and Wa > Wic 
W max. 



= 2W 
2/a 



15. Beam Continuous over Two Supports. — Two exterior sym- 
metrical loads. 






T 



Ri 




R (max. shear) 

M, distance x 

M max. from R to Ri 

TFmax. 

u 

Wa (3oZ - 4a ! ) 



W 
2 
Wx 

2 
Wa 

2 



2fs 



D t distance a 



Di, distance 



I 



12 E I 
Wa (l - 2<r.)g 



2 16 tf / 

Digitized by VJiOOQ 1C 



84 STRENGTH OF MATERIALS 

16. Beam Continuous over Two Supports. — Uniformly distributed 
load. 

w 

B — Ri = -= t max. shear 



Wa 

I 



M, distance x •• 



r m T\2 a ) 

TF(x* -Ix + oJ) 



21 

-4a) 



|«— | / A Mi at J2 and «i - -^f- 






21 _ 
max. if a > I (Vi - i) 
„ . . W (I - 4a) 
ift at center = - 

max. if a < I ( VT - *) 

Wimax . „*M± 

max. if a > I ( V* — i) 

JF.max. -y^ii- 

J — 4a _ 

max. if a < I ( V* - §) 

Deflection. — Formula for deflection is given in section on Beams 
under Various Loading Conditions. The depth of rolled steel beams 
should not be less than ix of the span, and plate girders not less 
than t^. 

Columns 

It was formerly assumed that the strength of a column depended 
largely on the condition of its ends. Many engineers now make no 
difference in their calculations for round-ended, pin-ended and 
square-ended 'columns. Usual factor of safety 5 or 6. 

Below are formulae for calculating the strength of columns:* 

(1) Steel Columns. 

P — total centrally applied load on column in pounds, in- 
cluding proper allowance for impact 
A = minimum area of cross sections in square inches 
I = total length of column in inches 
r = its least radius of gyration 
Then for steel columns of ordinary length where l/r does not ex- 
ceed 120 for the principal members, or 150 for the secondary mem- 
bers, and where P/A does not exceed 14,000 lb. \ 



P = A (l6,000 - 70 y) 



♦Formulae from Electrical Engineer's Handbook. 

Digitized by LiOOQ 1C 



COLUMNS 85 

(2) Cast Iron Columns. 

d =» diameter of circular column or shortest side 01 rect- 
angular column in inches 

-j- not to exceed 40 
a 

P - A (6,100 - 32 -j) 

(3) Timber Columns. 

Long-leaf yellow pine P = A |1300 f 1 - ^\ 1 

Short-leaf pine and spruce P = 4 1 1100 (l - ^J I 

Or if p is taken as the ultimate load in pounds per square inch, 
then the safe load for a given section may be obtained by multiply- 
ing the value of p as found from the formulae given below, 41 by the 
area of the section and dividing by the factor of safety. . 

Steel column with both ends fixed or resting on flat supports. 

50000 



1 +, 



36000 r» 

Steel column with one end fixed and resting on flat supports 
and the other end round or hinged. 

50000 
V - n — 



1 +; 



24000 r* 

Steel column with both ends round or hinged. 

50000 



V - 



1 + 



18000 r* 



Cast iron columns solid with both ends fixed or resting on flat 
supports, d = diameter of column. 

80000 

V - — 



i+ p 



800 d* 
* From Machinery's Handbook. 

Digitized by LiOOQ LC 



86 



STRENGTH OF MATERIALS 



Columns of H and I Sections* 
(Safe loads in thousands of lbs.) 
Allowable fiber stress per square inch, 13,000 lb. for lengths of 
80 radii or under; reduced for lengths over 60 radii. 





Depth and Weight of Sections 


Effective 
Length 


H 


I 


in 
Feet 


8-in. 

34 1b. 
perfi. 


6-in. 


5-in. 


4-in. 


15-in. 


12-in. 


10-in. 


9-in. 


8-in. 


7-in. 


6-in. 


5-in. 


4-in. 




23.8 
lb. 


18.7 
lb. 


13.6 
lb. 


42 1b. 
per ft. 


31H 
lb. 


25 
lb. 


21 
lb. 


18 
lb. 


15 
lb. 


12M 

lb. 


9H 
lb. 


7}4 
lb. 


• 2 
3 


130. 
130. 
130. 
130. 
130. 
130. 
130. 
130. 


91. 
.91. 
91. 
91. 
91. 
91. 


71.5 
71.5 
71.5 
71.5 
71.5 


52. 
52. 
52. 


162.2 
162.2 
162.2 
162.2 


120.4 
120.4 
120.4 
120.4 


95.8 
95.8 
95.8 


82. 
82. 
82. 


69.3 
69.3 
69.3 


57.5 
57.5 


46.9 
46.9 


37.3 
37.3 
33.3 

22.7 


28.7 
28.5 


4 


56.8 
50. 
43.2 
36.4 


44.5 
38.5 
32.5 
26.5 


24. 


5 


50.7 
45.7 
40.6 
35.6 
30.5 


94.4 
85.3 
76.2 
67.1 
58. 


77.8 

69.4 

61. 

52.6 

44.2 


63.2 

55.6 

48. 

40.4 

35. 

31.2 

27.4 
23.6 

19.8 
16. 


19.5 


6 


153.9 
140.1 
126.2 
112.3 
98.5 


109.9 
98.9 
87.9 
76.9 
65.9 


15.2 


7 


66. 
60.5 
55. 
49.5 

44. 

38.5 


18.8 
16.1 
13.5 
10.8 


13. 


8 
9 


86.7 

80.9 

75.1 

69.3 
63.5 

57.7 
51.9 


30.3 

26.9 

23.5 

20.1 
16.7 

13.3 


22.9 

19.9 

16.8 

13.8 
10.8 


10.8 
8.5 


10 


125.8 

119.4 
113. 

106.6 
100.2 

93.8 
87.3 
80.9 
74.5 


26.7 

24.2 
21.7 

19.2 
16.6 

14.1 


50.2 

45.7 
41.1 

36.5 
32. 

27.4 
22.9 


40. 

35.8 
31.5 

27.3 
23.1 

18.9 




11 
12 


86. 
79. 

72.1 
65.2 

58.2 
51.3 
44.4 
37.4 


59.9 
54.4 

48.9 
43.4 

37.9 
32.4 
26.9 




13 
14 


35.8 
33. 

30.3 
27.5 
24.8 
22. 

19.3 
16.5 




15 
16 

17 
18 


47.6 
44.7 
41.8 
38.9 

36. 
33.1 




19 
20 


69. 
65.8 




Area in 
sq. ins. 


10. 


7. 


5.5 


4. 


12.48 


9.26 


7.37 


6.31 


5.33 


4.42 


3.61 


2.87 


2.21 



Safe load values above, upper zigzag line are for ratios of — not 
over 60, those between the zigzag lines are for ratios up to 120 
and those below lower zigzag line for ratios over 200. 

* Carnegie Steel Co. Pocket Companion. 



Digiti 



zed by G00gk 



SQUARE WOODEN COLUMNS 



87 



Cast iron column, hollow, round, both ends fixed or resting on 
flat supports, d = outside diameter of column. 

80000 

P "" Hi— 

1 + 



800 cP 

Cast iron column, hollow, square, with both ends fixed or resting 
on flat supports, S = outside dimension of square. 

80000 

p- — 

1 + 



1000 & 

For square wood columns with flat supports, the side of the 
square being S, 

5000 

V *— 



1 + 



250 /S* 



Square Wooden Columns 

(Safe loads in thousands of pounds) 

America Railway Engineering Association Formulae 

Long-Leaf Pine — White Oak — 1,300 f 1 — — ^J 



Length 
Feet 



Side of Square (Inches) 



10 



12 



16 



18 



20 



10 
11 
12 



14 
16 



18 
20 



15.6 



15.6 
14.6 
13.5 



12.5 
11.4 



10.4 



35.1 



34.3 
32.8 



31.2 
29.6 
28.1 



25.0 



62.4 



62.4 
60.3 
58.2 



54.1 
49.9 



45.8 
41.6 



97.5 



93.6 

88.4 



83.2 

78.0 



140.4 



137.3 



131.0 
124.8 



191.1 



189.3 
182.0 



249. C 



315.9 



390.0 



~ 



88 



STRENGTH OF MATERIALS 



Round Wooden Columns 

(Safe loads in thousands of pounds) 

Long Leaf Pine— White Oak— 1,300 (l - ^gj 



Length 


Diameter (Inches) 


Feet 


4 


6 


8 


10 


12 


14 


16 


18 


20 




12.3 


27.6 


49.0 


76.6 


110.3 


150.1 


196.0 


248.1 




5 
6 
7 


12.3 
11.4 
10.6 

9.8 
9.0 

8.2 




8 
9 


27.0 
25.7 

24.5 
23.3 
22.1 

19.6 




10 
11 
12 


49.0 
47.4 
45.7 

42.5 

39.2 

35.9 
32.7 




14 


73.5- 

69.4 

65.3 
61.3 




16 


107.8 

102.9 
98.0 




18 
20 


148.7 
142.9 


306.3 



Loads above horizontal lines are the maximum allowable safe 
loads. 

Safe Load on Standard Wrought Iron Pipe Columns 

(For table of sizes see page 508.) 

Both Ends Fixed Factor of Safety = 6 In Tons of 2000 lb. 



Size 


Length of Column — Feet 


Pipe 
Inches 


8 


10 


12 


14 


16 


18 


20 


2 


2.0 


1.8 


1.4 










2V 2 




3,35 


2.8 


2.4 


2.1 






3 




4.8 


4.3 


3.8 


3.36 


3.08 




VA 




6.07 


5.52 


5.1 


4.47 


4.02 




4 




7.67 


7.1 


6.56 


6.02 


5.4 




4« 




9.32 


8.69 


8.16 


7.52 


6.98 




5 






10.53 


9.93 


9.33 


8.6 


8.0 


6 






14.6 


13.82 


13.03 


12.37 


11.75 


7 






18.58 


17.9 


17.2 


16.5 


15.76 


8 






23.13 


22.45 


21.7 


20.85 


20.11 



JUUVlL 



TORSIONAL STRESSES 



89 



Safe Load on Strong and Extra Strong Wrought Iron Pipb 

Columns 

Both Ends Fixed Factor of Safety « 6 In Tons of 2000 lb. 

Strong 



Size 


Length of Column — Feet 


Pipe 
Inches 


8 


10 


12 


14 


16 


18 


20 


2 

2H 

3 

3^ 

4 

5 

6 

7 
8 


3 


36 


3.10 
4.93 
6.78 
9.05 
11.56 
12.23 


2.46 

4.41 

6.21 

8.43 

10.94 

11.62 

15.94 

23.03 

29.24 

33.84 


ski 

5.64 
7.80 
10.30 
10.97 
15.27 
22.18 
28.52 
33.34 


5.10 
7.18 
9.52 
10.18 
14.40 
21.26 
27.73 
32.53 


i'.w 

6.58 
8.88 
9.64 
13.67 
20.54 
26.90 
31.63 


\2.M 
19.80 
25.73 
30.68 









Extra Strong 








2 


6.04 


5.57 


4.43 










2H 




8.79 


7.86 


6.80 


6.12 






3 




13.19 


12.08 


10.97 


9.92 


8.94 




3H 




16.55 


15.41 


14.26 


13.13 


12.05 




4 




21.24 


20.11 


18.92 


17.50 


16.32 




4^ 




25.29 


24.03 


22.69 


21.05 


19.94 




5 






29.58 


28.35 


26.73 


25.38 


24.11 


6 






42.79 


41.21 


39.50 


38.16 


36.80 


7 






56.23 


54.85 


53.34 


51.73 


49.49 


8 






65.66 


64.70 


63.11 


61.37 


59.52 



Torsional Stresses. — To find the safe torsional load of a circular 

shaft. 

T = twisting moment 

d\ = outside diameter of the shaft 

d\ = inside diameter of the shaft 

/ = safe stress per square inch of section 

. d t * - a\* 



Then for a hollow shaft T - jzf 



di 



If the shaft is solid d 2 = 0and!T = ^/(i 8 



Digiti 



zed by G00gk 



90 STRENGTH OF MATERIALS 

Springs. — To determine the size of steel wire for wire springs, 
Let D s = mean diameter in inches of coii. 

W = total load in pounds 

d = diameter of round or side of square steel wire in inches 

c = 11,000 

Then d = 3|/^^ 

To obtain the number of free coils N when the above data are 
known and the compression C is decided on, use the formula 
_ Cd'a 
WD* 
where d = size in sixteenths of an inch 

a = 26 for round (British Admiralty) or 22 (Board of 
Trade) 
= 32 for square (British Admiralty) or 30 (Board of 
Trade) 
Formula for Calculating Strength of Tubes, Pipes and Thin 
Cylinders. — The one (Barlow's) commonly used assumes that the 
elasticity of the material at the different circumferential fibers 
will have their diameters increased in such a manner that the 
length of the tube is unaltered by the internal pressure. 
Let t = thickness of wall in inches 

p = internal pressure in pounds per square inch 

S = allowable tensile strength in pounds per square inch 

D = outside diameter in inches 

n = safety factor as based on ultimate strength 

rm. P 2* J DP 

Then -g- - jj * ~ -2S 

_2St _ D P 

P - ~D S - ~2t 

S = for butt-welded steel pipe 



n 

50000 
n 

60000 
n 

28000 



for lap-welded steel pipe 
for seamless steel tubes 
for wrought iron pipe 



n 
In the above, the thickness of the wall t is assumed to be small 



ioogle 



WROUGHT IRON TUBES 



91 



compared to the diameter. The thicknesses of thin pipes under 
the same internal pressure should increase directly as their diameters. 
A cylinder under exterior pressure is theoretically in a similar 
condition to one under internal pressure as long as it remains a 
true circle in cross section. 

BUBSTING AND COLLAPSING PRESSURES OP WROUGHT IRON TUBES 
[Lukens Iron & Steel Co.] 







Burst- 


Collaps- 






Burst- 


Collaps- 




Thick- 


ing 


ing 


External 


Thick- 


ing 


ing 


Exter- 


Per 


Per 


Per 


Per 


nal Dia. 


ness 


Sq. Inch of 


Sq. Inch of 


Dia. 


ness 


Sq. Inch of 


Sq. Inch of 






Internal 


External 






Internal 


External 






Surface 


Surface 






Surface 


Surface 


(Ins.) 


(Ins.) 


(Lb.) 


(Lb.) 


(Ins.) 


(Ins.) 


(Lb.) 


(Lb.) 


1.25 


.083 


7700 


6500 


3.25 


.12 


4000 


2700 


1.375 


.083 


6900 


5800 


3.5 


.134 


4200 


2700 


1.5 


.083 


6200 


5200 


3.75 


.134 


3900 


2400 


1.625 


.083 


5700 


4700' 


4. 


.134 


3600 


2100 


1.75 


.083 


5300 


4300 


4.25 


.134 


2400 


1900 


1.875 


.083 


4900 


4000 


4.5 


.134 


3200 


1700 


2. 


.083 


4500 


3700 


4.75 


- .134 


3000 


1600 


2.125 


.095 


4900 


3800 


5. 


.134 


2800 


1400 


2.25 


.095 


4600 


3600 


5.25 


.148 


3000 


1400 


2.5 


.109 


4800 


3600 


5.5 


.148 


2800 


1200 


2.75 


.109 


4300 


3100 


5.75 


.148 


2700 


1100 


3. 


.12 


4400 


3000 


6. 


.148 


2600 


1000 



Strengths of Various Fittings. — 

Let d — diameter of iron in inches 

Then working load of a hook = -.- tons 

working load of a ring bolt =» 2d 2 tons 
working load of eye bolt = 5cP tons 
working load of a straight shackle = 3d 2 
working load of a bow shackle = 2 l /faP 
Suppose in a chain having a shackle, hook and ring bolt, it is de- 
sired to have all the parts of approximately the same strength, 
assuming the link of the chain as 1, then the eye of eye bolt = 1% 

shackle = 1% 

ringbolt = 1% 

hook at back =3}^ 
See also Chain table. 

[Abstracts from Naval Constructor, G. Simpson.] 

Digitized by LiOOQ 1C 



92 



STRENGTH OF MATERIALS 



The strength of a bitt or bollard can be calculated as a beam 
supported at one end and loaded at the other. Usually a thickness 
of 1}4 his. is sufficient, but the outside diameter depends on the 
size of the chain or hawser that will be used. For steel wire hawsers, 
bitts should not be less in diameter than four times the circumference 
of the hawser. 

Riding Bitts or Bollards 



Dia. in Inches 


Dia. of Cable in Inches 


16 


m 


18 


m 


20 


i% 


22 


IK 


24 


2 


26 


2H 


28 


2M 



As to the working load for rivets 

allow 1 ton for each % inch rivet 
2 tons for each J£ inch rivet 
S}4 tons for each 1 inch rivet 

The breaking stress in tons of a rivet in single shear is about 
25 times the sectional area A of the rivet, and in double shear 50 
times. 

If S — safe shearing stress on a rivet in tons per square inch 
W = working load on a rivet 
A — sectional area of the rivet in square inches 

Then W — S A f or single shear, or 
— 1% S A for double shear 

See also section on Rivets and Riveting. Bolts may be similarly 
calculated. 



Digiti 



zed by G00gk 



BOLTS 93 

Shearing and Tensile Strength of Bolts 





Area 


Shearing Strength 


Tensile Strength 


Ultimate 




CroeB Sections 


Safe Loads 


Safe Loads 


Tensile and 

Shearing Strain 

at 50,000 lb. 


du: 

of 
Bolt 


Full Bolt 


Root of Thd. 


Root of Thd. 


Per Square Inch 




Bolt 


Root 

of 

Thread 


7500 
lb. per 
Sq.In. 


10000 
lb. per 
Sq.In 


7500 
lb. per 
Sq. In. 


10000 
lb. per 
Sq.In. 


10000 
lb. per 
Sq.In. 


12500 
lb. per 
Sq.In. 


Full 
Bolt 


Root 

of 
Thread 




sq. m. 


sq. in. 


lb. 


lb. 


lb. 


lb. 


lb. 


lb. 


lb. 


lb. 


H 

P. 

A 


.049 
.076 
.110 
.150 


.026 
.045 
.067 
.093 


368 
575 
828 
1127 


491 
767 
1104 
1503 


202 
341 
509 
700 


269 
454 
678 
933 


269 
454 
678 
933 


3*36 
568 
848 
1166 


2455 
3835 
5520 
7515 


1345 
2270 
3390 
4665 


A 

Vs 
H 
% 


.196 
.248 
.306 
.441 
.601 


.125 
.162 
.201 
.302 
.419 


1472 
1861 
2301 
3314 
4510 


1963 
2485 
3068 
4418 
6013 


943 
1216 
1514 
2265 
3145 


1257 
1621 
2018 
3020 
4193 


1257 
1621 
2018 
3020 
4193 


1571 
2026 
2523 
3775 
5241 


9815 
12425 
15340 
22090 
30065 


6285 
8105 
10090 
15100 
20965 


1 

m 


.785 

.994 

1.227 

1.484 


.551 

.693 

.889 

1.054 


5891 
7455 
9204 
11137 


7854 
9940 
12272 
14849 


4133 
5198 
6674 
7906 


5510 
6931 
8899 
10541 


5510 
6931 
8899 
10541 


6888 
8664 
11124 
13176 


39270 
49700 
61360 
74245 


27550 
34655 
44495 

52705 




1 767 
2.073 
2.405 
2.761 


1.293 
1.514 
1.744 
2.049 


13253 
15554 
18040 
20709 


17671 
20739 
24053 
27612 


9704 
11362 
13081 
15368 


12938 
15149 
17441 
20490 


12938 
15149 
17441 
20490 


16173 
18936 
21801 
25613 


88355 
103695 
120265 
138060 


64690 
75745 
87205 
102450 


2 

2H 
2M 


3.141 
3.976 
4.908 
5.939 


2.300 
3.021 
3.716 
4.619 


23562 
29821 
36815 
44547 


31416 
39761 
49087 
59396 


17251 

22660 
27872 
34647 


23001 
30213 
37163 
46196 


23001 
30213 
37163 
46196 


28751 
37766 
46454 
57745 


157080 
198805 
245435 
296980 


115005 
151065 
185815 
230980 


3 

3tf 
3H 
3^ 


7.068 
8.295 
9.621 
11.044 


5.427 
6.509 
7.549 
8.641 


53015 
62219 
72158 
82835 


70686 
82958 
96211 
110447 


40708 

48819 
56618 
64809 


54277 
65092 
75491 
86412 


54277 
65092 
75491 
86412 


67846 
81365 
94364 
108015 


353430 
414790 
481055 
552235 


271385 
325460 
377455 
432060 


4 

4* 
4H 
4N 


12.366 
14.186 
15.904 
17.720 


9.992 
11.330 
12.740 
14.220 


94248 
106397 
119282 
132904 


125664 
141863 
159043 
177205 


74947 
84977 
95554 
106654 


99929 
113302 
127405 
142205 


99929 
113302 
127405 
142205 


124911 
141628 
159256 
177756 


628320 
709315 
795215 
886025 


499645 
566510 
637025 
711025 


5 

5V£ 
5« 


19.635 
21.647 
23.758 
25.967 


15.765 
17.574 
19.267 
21.262 


147263 
162356 
178187 
194754 


196350 
216475 
237583 
259672 


118244 
131809 
144509 
159465 


157659 
175745 
192678 
212620 


157659 
175745 
192678 
212620 


197074 
219681 
240848 
265775 


981750 
1082375 
1187915 
1298360 


788295 
878725 
963390 
1063100 


6 


28.274 


23.094 


212057 


282743 


173210 


230947 


230947 


288684 


1413715 


1154735 



Google 



94 



STRENGTH OF MATERIALS 



Tests of Hooks and Shackles 

Experience has shown that the same brand of iron or steel will 
not maintain the same tensile strength under various conditions. 
The following tables give the results of tests of hooks from % in. to 
3 ins. diameter and of shackles from 3^ in. to 3 ins. diameter/ the 
figures being taken from the catalogue of the Boston & Lockport 
Co., Boston, Mass. In the column "Size, Inches," the diameter 
of the hook or shackle is meant. It is suggested that not more 
than 20% of the tensile strength as given in Column 2 be reckoned 
as the working load, and on this basis Column 4 is calculated. 
Ordinarily the hook of a block is the first to give way, and when 
heavy weights are to be handled, shackles are far superior to hooks. 
By many tests it has been proven that flattening a hook adds from 
12 to 15% to its ultimate strength. " 



Tests of Hooks 

[Boston & Lockport Co.] 
In column Size, Inches, the diameter of the hook or shackle is meant. 



Size, Inches 


Tensile 
Strength, Lb. 


Description 
of Fracture 


Working Load in Lb., 

Based on 20% of 

the Tensile Strength. 

That is a Factor of 

Safety of 5 


% 


1,040 

1,^15 

2,010 

2,650 

3,210 

4,750 

6,680 

13,720 

14,540 

16,950 

18,340 

21,220 

25,780 

30,250 

38,100 

41,150 

46,145 

65,150 

110,000 


Straightened 
the Hook 

u 
u 
It 
It 
tt 
ft 
ft 
tl 
ft 
tt 
tt 
tt 
tt 
ft 
tf 
ft 
tf 
tt 


208 


A 


249 


y 2 


402 


& 


530 


y 8 


612 


% 


950 


J4 


1,336 


1 


2,744 


m - 

\\i 


2,908 
3,390 


1% 


3,668 


\y 2 


4,244 


\y, 


5,156 


1% 


6,050 


iu 


7,620 


2 


8,230 


2M 


9,229 


2 X A 


13,030 


3 


22,000 







y Google 



Tests op Shackles 



Sise, Inches 



Tensile 
Strength, Lb. 



Description 
of Fracture 



Working Load in Lb., 

Based on 20% of the 

Tensile Strength 



H 

% 
% 
V* 

l 

IX 
IK 

W% 
l l A 
IX 

2 

2H 
2V 2 
3 



15,400 

20,500 

22,700 

40,100 

66,380 

68,900 

78,900 

105,900 

121,850 

126,700 

150,600 

170,500 

230,200 

260,500 

280,600 

498,000 



Sheared 
Shackle Pin 



3,080 
4,100 
4,540 
8,020 
13,276 
13,780 
15,780 
21,180 
24,370 
25,340 
30,120 
34,100 
46,040 
52,100 
56,120 
99,600 



Weldless Eye Bolts 
(Either plain or shoulder pattern) 



Shank 




Diameter Eye 


Capacity, Net Tons 






Maxi- 
mum 


























Standard 


Length 






Safe 


Average 


Approx- 


Diam- 


Length 
Under 


in 


Inside 


Outside 


Working 


Load at 


imate 


eter 


Stock 






Load 


Elastio 


Breaking 




Eye 










Limit 


Strain 


X 


IX 


4M 


1 


m 


.7 


1.4 


3. 


A 


IX 


IX 


1* 


1H 


1. 


2. 


4. 


X 


IX 


*X 


1A 


2A 


1.3 


2.5 


5. 


A 


W 


m 


1A 


2A 


1.5 


3. 


6. 


X 


W 


±X 


IX 


2« 


2. 


4. 


8. 


X 


2 


5 


IX 


2*i 


3. 


6. 


12. 


X 


2X 


5 


Itt 


3M 


3.5 


7. 


16. 


l 


2y 2 


5 


1*1 


3A 


4. 


8. 


20. 


1H 


IX 


5 


2 


4 


5. 


10. 


23. 


Hi 


3 


6 


2A 


4A 


7.5 


15. 


33. 


IX 


3^ 


6 


2X 


5A 


9. 


18. 


42. 


IX 


3X 


6 


2H ■ 


6A 


11. 


21. 


53. 


2 


4 


6 


3M 


6H 


13. 


25. 


68. 


2X 


5 


6 


4 


8A 


16. 


32. 


85. 



05 



Drop Forged Hoist Hooks With Eye 
(Capacity with plain shank the same) 



Diameter of Eye 


Ertreme Dimensions 


Capacity, Net Tons 












Average 


Approximate 










Safe 


Load 


Load 


Inside 


Outside 


Length 


Width 


Working 
Load 


at 
Elastic 
Limit 


Required to 

Straighten 

Out 


X 


IX 


4H 


2^ 


.5 


.9 


1.9 


X 


IX 


m 


3H 


.6 


1.2 


2.3 


1 


2 


5Vs 


3H 


.7 


1.5. 


3. 


IX 


2X 


6A 


3^ 


1.2 


2.5 


5.7 


V4 


2}4 


■VA 


4^ 


1.7 


3.5 


7. 


1% 


2X 


7X 


4% 
5^ 


2.1 


4.2 


8.5 


IX 


3 


8A 


2.5 


5.4 


10. 


m 


ax 


9A 


6^ 


3. 


6.2 


13. 


IX 


VA 


10^ 


6% 


4. 


8. 


17. 


2 


4 


11H 


7J^ 


4.7 


9. 


19. 


2% 


4% 


13 


8}< 


5.5 


11. 


26. 


2H 


5X 


14K 


9M 


6.8 


13. 


32. 


vx 


VA 


ViX 


10K 


8. 


17. 


35. 


ZX 


7. 


l»H 


13 


11. 


21. 


48. 


4 


&X 


22^ 


14% 


20. 


40. 


80. 







Iron Guy Shackles 






Sise in 
Inches of 


Gov. Test 
Maximum 


Length 


Width 

Between 

Eyes 

Inches 


Diameter 
of Pin 


Approximate 
Weight 


Shackle 


Strength 


Inside 


of Each 


(Diam. of 
Iron in Bow) 


in 
Pounds 


Inches 


Inches 


in 
Pounds 


H 


10,890 


IK 


% 


A 


0.30 


ft 


15,200 


VA 


H 


ti 


0.48 


18,390 


VA 




0.70 


A 


24,800 


VA 


H 


0.90 


X 


33,400 


2X 


1A 


X 


1.40 


X 


43,400 


3 


i& 


% 


2.20 


X 


55,200 


3^ 


\x 


1 


3.40 


1 


74,900 


4 


IX 


IX 


5.00 


IX 


90,200 


4^ 


va 


IX 


6.80 


IX 


92,040 


5 


2 


m 


9.40 


1% 


94,100 


VA 


2% 


m 


12.20 


IX 


103,800 


6 


2X 


w% 


16.40 


W% 


155,542 


6^ 


2A 


m 


19.00 


IX 


172,400 


7 


2X 


VA 


24.00 


2 


235,620 


8 


Wa. 


2A 


38.20 



From J. H. Williams & Co., Brooklyn. 

96 



Digitized by 



Google 



TURNBUCKLES 



97 



TURNBUCKLES 

Drop-forged, with hook and eye, shackle and eye, two eyes, two 
hooks, two shackles, or hook and shackle. 



Size Turn- 






Amount 








buckle 






of 




Length 




and 


Approxi- 


Recom- 


Take-up 


Length 


Pull to 


Approxi- 


Outside 


mate 


mended 


Length 
in the 


Pull 


mate 


Diameter 


Breaking 


Working 


Buckle 


When 


Weight 


of 


Strength 


Load 


Clear 


Outside 


Extended 


Each 


Thread 


in Pounds 


in Pounds 


Between 


in Inches 


in 


in Pounds 


in 






Heads 




Inches 




Inches 






in Inches 








H 


1,350 


270 


4 


4J£ • 


12 


.40 


ft 


2,250 


450 


4J* 


5M 


13H 


.60 


3,350 


670 


VA 


6% 


14 


.90 


S 


4,650 


930 


5 


VA 


16J* 


1.31 


6,250 


1,250 


6 


m 


18M 


1.87 


A 


8,100 


1,620 


7K 


9 


23H 


3.00 


H 


10,000 


2,000 


sy 2 


103^ 


24^ 


3.69 


*A 


15,000 


3,000 


9X 


llJi 


27^ 


5.81 


v% 


21,000 


4,200 


10 


12X 


30M 


8.$1 


1 


27,500 


5,500 


11 


14 


33 


12.56 


\y% 


34,500 


6,900 


12 


15H 


39 


17.00 


Wa. 


44,500 


8,900 


13 


165* 


40 


25.00 


m 


52,500 


10,500 


14 


18 


50 


36.00 


1H 


64,500 


12,900 


15 


19M 


51 


40.00 


W& 


75,500 


15,100 


16 


21 


51^ 


48.00 


l« 


87,000 


17,400 


' 18 


23 


55H 


52.00 


W* 


102,500 


20,500 


18 


23 


66 


89.00 


2 


115,000 


23,000 


24 


31 


74 


98.00 


2H 


132,500 


26,500 


24 


31 






2H 


151,000 


30,200 


24 


32 







Formulae for Circular Davits. — 



D 
W 



R = 

a = 

K - 



diameter of each davit in inches 

weight of boat with full complement of equipment and 

persons (figured at 165 lb. each) plus weight of 

tackle and blocks, all in pounds 
radius of overhang of davit arm in inches 
increase of W to take care of increase in stresses 

when ship is listed 15° 
fiber stress allowed in pounds per square inch 



Then D 



-?■ 



1W XRX (1 +a) 



XK 



Digiti 



zed by G00gk 



STRENGTH OF MATERIALS 



The average values given below substituted in the above formula 
will give a handy equation for calculating the diameter of the davit. 
• a = 25 and K = 12000 
Hence D - .0812 %/~W~~XR 
For davits of structural steel their dimensions must give the 
same strength as round bar davits as figured with the above formula. 
Lloyd's rule for boat davits. 
L = length of boat 
B = beam of boat 
D = depth of boat 

H = height of davit above its uppermost point of support 
S = spread 

AU the above dimensions are in feet. 
C = constant = 82 when the davit is of wrought iron and 
of sufficient strength to safely lower the boat fully 
equipped and carrying the maximum number of 
passengers 
d = diameter of davit in inches 



-v 1 - 



IL X B X D (H + 4S) 
C 

Davits may be calculated as beams, fixed at one end and loaded 
at the other. See also section on Anchor Davits. 

Stresses in Cranes, Derricks, and Shear Poles. — The stresses 
in any member can be found graphically. Thus in Fig. 13 lay off 




^Bwro^sar 



Figure 13 



Digiti 



zed by G00gk 



CRANES, DERRICKS, SHEAR POLES 



99 



the distance p to any scale, say 1 inch = 1,000 lb., it representing 
the downward force or weight of the load, and draw a parallelo- 
gram with the sides b t parallel to B and T so that p is the diagonal. 
By scaling t the tension in the tie T is obtained and similarly the 
compression b in the brace. The above also applies to Fig. 14. 




Figure 14 
In a guyed crane or derrick as Fig. 15 the strain in B is 



PXB 

A 1 



A 1 being that portion of the vertical included between B and T 
wherever T may be attached to A. If T is attached to B below its 




Figure 15 



K^AV^/^^WWiUIWw 



Digiti 



zed by G00gk 



100 



STRENGTH OF MATERIALS 



extremity, there may be in addition a bending strain B due to a 

tendency to turn about the point of attachment of T as a fulcrum. 

The strain in T may be calculated by the principle of moments. 

The moment of P is P X c The moment of the strain on T is 

P X c 
T X d t therefore the strain on T is — . As d decreases the 

strain on T increases. 

The strain on the guy rope G is calculated by the principle of 

moments. The moment of the load about the bottom of the mast 

is P X c. If the guy is horizontal the strain in it is F and its 

P X c 
moment is F X /, and F — — 7 — . If it is inclined, the moment 

is the strain G X the perpendicular distance of the line of its direc- 
P Xc 



tion or g, and G 



The guy rope having the least strain is 



the horizontal one F, and the strain in G = strain in F X secant of 
the angle between F and G. As G is made more nearly vertical g 
decreases and the strain increases. 

Another case is where the tie T is not perpendicular to A 1 , or 
the post A may be omitted and T extended to the ground. The 
parallelogram of forces may be applied and the equations, 

D y (P D y D 

(1) tension in T = — jr — and (2) compression in B = — — — ,hold. 




Figure 16 

Shear poles with guys. See Fig. 16. First assume that the two 
masts act as one placed at B D and the two guys as one at A B. 

Digitized by VJiOOQlC 



RIVETS AND RiyETING 



101 



Calculate the strain in A B and B I) as in the previous case. Mul- 
tiply half the strain in A B (or B D) by the secant of half the angle 
the two masts or guys make with each other to find the strain in 
each mast or guy. 

(From Mech. Eng'rs Pocket Book. W. Kent) 

RIVETS AND RIVETING 

Different types of rivets are shown in Fig, 17. Pan- and button- 
head rivets % hich in diameter or over have coned or swelled necks 
for punched plates, and straight necks for drilled. The advantage 
of swelled-neck rivets is that the diameter of the punched hole 
on the die side is always slightly larger than on the punched side. 
In assembling the plates are reversed, and thus with swelled-neck 
rivets the holes are completely filled. 



//ecrc/± 



u u 



o a o 




_^"«* nee* I 



A 

9 9 £ 

Figure 17.— Rivet Heads and Points. 

A = pan head. B = snap or button head, makes a neater appearance than pan 
head. C = flush or countersunk flat head. D = countersunk raised head. E = 
tap rivets. They are H of an inch greater diameter than is required for a plain 
rivet to the same thiciaiess of plate or shape (Am. Bureau of Shipping Rutes). 
F " snap point, proportions same as button head. G «= hammered point. H =* 
countersunk point, proportions same for countersunk head. 



Digiti 



zed by G00gk 



102 .. • - -STRENGTH. OF MATERIALS 

Form of Rivet in outside plating 



I* A/- 




Proportions. — The proportions of 

the heads and countersinks vary 

Tapered neck to with the different classification 

feguf in* *i£ societies. The U. S. Navy has its 

tion to thick- own standard. There are thus no 

universal standards, although 

Lloyd's is doubtless adopted more 

than any other for merchant work. 

Below are Lloyd's proportions. 



Countersink. 



YZZ^ 



W-3-4 



Diameter of Rivet, Ins. 


A, Ins. 


B, Ins. 


y* 


1 

1A 


H 


% 


It 


y % 


1 


1A 


\y % 


1A 







Countersink to extend through the whole thickness of the plate 
when less than U / M or .7 ins. thick, when .7 ins. or above the coun- 
tersink to extend through nine-tenths the thickness of the plate. 



Lloyd's Rules for the. Diameter of Rivets 



Thickness of plate in ins. 
Diameter of rivet in ins. 



.22 and 


.34 and 


.48 and 


.66 and 


.88 and 


under .34 


under .48 


under .66 


under .88 


under 1.14 


H 


% 


H 


1 


M 



1.14 and 
under 1.2 



Lengths of Rivets for Ordering. — The length for ordering pan- 
and button-head rivets is measured exclusive of the head; for 
countersunk rivets and taps the ordered length includes the head 
to the top of the countersink. 



Digiti 



zed by G00gk 






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sp«aq 



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•+ 



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I* 



J* 






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H 



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opisisj 



opie JS9^T 



sopis q^og 



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9piS Jfto££ 





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103 





zed by G00gk 



104 



STRENGTH OF MATERIALS 



Allowance for Points in Length of Rivets with Two Thick- 
nesses Connected 



Type of Point 


Diameters of Rivets (Ins.) 




H 


H 


H 


Vi 


i 


1M 


Countersunk 

Hammered 

Snap '. 




H 

1 

7 A 


H 

H 
1H 


k 


i 

H 
IN 


1M 


Oval 









The above allowances are based upon the average practice at 
various U. S. Navy and private ship yards. 

Rivets are usually shipped in kegs of 100 and 200 lb. In ordering 
the diameter should be given first thus: }4 in. X 3 ins. 

Materials. — To prevent galvanic action as far as possible iron 
rivets should be used in iron plates, and steel in steel plates. It 
is important that rivets have a high tensile strength and resistance 
to shear. For specifications see Shipbuilding Materials. 

Strength of Rivets. — The diameter of a rivet in inches for 
single shear is given by the formula D =>i/ — ^ and in double 



shear, 



■•/s 



or .707 D in single shear, where 



D = diameter of rivet 

c = factor of safety 

F = shearing force 

S = ultimate shearing strength of the material 



Shearing and Tensile Strength of Steel Rivets in Pounds 
per Square Inch 



HIn. 



Kin. 



»/» In. 



Kin. 



Hln. 



Shearing lb. per sq. in. 
Tensile lb. per sq. in. 



9,225 
10,600 



13,150 
16,500 



18,000 
20,000 



20,525 
23,800 



27,100 
31,400 



RIVETED JOINTS 



105 



Table of Ultimate Single Shearing Strength of Rivets 



Diameter in Fractions (Ins) 



Diameter 

in Decimals 

(Ins.) 



Steel at 

40,000 Lb. 

Per Sq. Inch 



Steel at 

45,000 Lb. 

Per Sq. Inch 



x. 



& 



B: 

it 



.125 
.187 
.250 
.312 
.375 
.437 
.500 
.562 
.625 
.687 
.750 
.812 
.875 
.937 
.000 
.062 
.125 
.187 
.250 
.312 
.375 
.437 
.500 



490 

1,104 

1,963 

3,068 

4,418 

6,013 

7,854 

9,940 

12,272 

14,848 

17,671 

20,739 

24,052 

27,611 

31,416 

35,465 

39,760 

44,300 

49,088 

54,120 

59,396 

64,920 

70,684 



552 

1,242 

2,209 

3,452 

4,970 

6,735 

8,836 

11,183 

13,806 

16,705 

19,880 

23,332 

27,060 

31,064 

35,343 

39,899 

44,731 

49,838 

55,224 

60,885 

66,820 

73,035 

79,519 



From Lukens Iron & Steel Co. 

Riveted Joints. — A riveted joint may fail: (1) in the plate, by 
tearing out or across from hole to hole; (2) in the rivet, by shearing; 
and (3) in the plate or rivet, by a crushing of the material. 

The failure of a joint by the tearing out of the plate in front 
of the rivet may be prevented by placing the rivets at a proper 
distance from the edge of the plate. This has been found to be 
about one diameter in the clear or one and a half diameters of the 
rivet from the edge of the plate to the center of the rivet. . 

To determine the efficiency of a riveted joint, calculate the 

ways it may fail, and the one giving the least result will show the 

actual strength of the joint. If this equals T r and T equals the 

tensile strength of the solid plate then the efficiency of the joint 

T 
is 7=r which can be expressed as a percentage. Thus the average 

relative strengths of joints in boilers are as follows: 

Single riveted lap 55% 



Digitized 



by Google 



106 STRENGTH OF MATERIALS 

Double riveted lap 70% 

Single riveted butt joint 65 

Double riveted butt joint 75 

Triple riveted butt joint 80 

Quadruple riveted butt joint 85 

From the following equations the unit stresses may be computed 
when the other quantities are known, and by comparing them 
with proper allowable unit stresses the degree of security of the 
joint is estimated. 

d — diameter of rivets T = tensile strength of plate 

t =s thickness of plate C — crushing strength of rivets 

p = pitch of rivets S = shearing strength of rivets 

All dimensions are in inches, and stresses in pounds per square 
inch. 

Lap Joint Single RiveteU. 

Resistance to tearing plate between rivets = t (p — d) T 

Resistance to crushing of one rivet =■ tdC 

Resistance to shearing of one rivet = Ji r d? S 

Lap Joint Double Riveted. 
Resistance to tearing plate between two rivets — t (p — d) T 
Resistance to crushing of two rivets = 2 t d C 



Resistance to shearing of two rivets 



2*d*S 



Butt Strap, Single Riveted, Two Cover Plates. 
Resistance to tearing plate = t (p — d) T 

Resistance to crushing of one rivet «* tdC 



Resistance to shearing of one rivet 



2ird*S 



Butt Strap, Double Riveted, Two Cover Plates. 

Resistance to tearing plate = t (p — d) T 

Resistance to crushing of two rivets = 2 t d C 



Resistance to shearing of two rivets 



4«-«PS 



The total shearing strength of a rivet in double shear is usually 
taken as about 1.75 the strength in single shear. 



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108 



Number of Cone Head Rivets In 100 Pounds* 
Scant Diameter 



Length 
Under 
Head 



Diameter 



W 



H" H* H" H" H 



1H" IK 



l 

i« 
ig 

2 

2H 
2H 
2% 

i 

2% 
3 

vt. 

4 

m 

5 

»: 

6 , 
6H 

7 . 



1162 
1075 

1010 
943 
892 
840 
800 
757 
724 
689 



632 
609 
584 
561 
543 
523 
507 

490 
460 
436 
411 

390 
371 
354 



324 
311 



277 

258 



242 



840 
787 

735 
694 
657 
621 
591 
564 
537 
515 

495 
476 
456 
440 
425 
409 
396 
384 

371 
350 
331 
313 



284 
271 
259 

248 



221 



213 
199 



186 



645 
606 

568 
537 
510 
483 
460 
440 
420 
403 

387 
371 
358 
346 
333 
322 
312 
302 

293 
276 
261 
248 



225 
215 
205 

197 
189 
182 
176 



158 
148 



446 
423 
401 
383 
364 
349 
334 
321 

308 
296 
286 
276 
267 
258 
250 
242 

235 
222 
210 
200 

190 
181 
173 
166 

159 
153 
147 
142 

137 
128 

120 



855 
337 
821 
306 



259 

249 
240 
232 
224 
216 
210 
203 
197 

191 
181 
172 
163 

156 
149 
142 
136 

131 
126 
121 
117 

113 
106 

100 



275 
262 
251 
240 
230 
221 
213 

205 
198 
191 
185 
179 
173 
168 
163 

159 
150 
143 
136 



124 
119 
114 

109 
105 
101 
98 

95 



84 



217 
208 
200 
192 
185 
178 

172 
166 
161 
156 
151 
147 
142 
138 

135 
128 
120 
114 

109 
105 
101 
97 

9-* 
90 

86 
83 

80 
75 

71 



153 
147 
142 
136 
131 
128 

123 
119 
114 
112 
108 
105 
103 
100 

97 
92 

87 
84 

80 
76 
74 
70 

68 
66 
63 
61 

59 
56 

52 



Exact 
Dia. 



107 
104 
100 
97 
93 

90 
87 
85 
82 
80 
78 
75 
74 

71 
68 
65 
62 



Exact 
Dia. 



78.7 
75.7 
73.5 
71.4 

68.9 
67.1 
65.3 
63.2 
61.7 
60.2 
58.4 
57.1 

55.8 
53.1 
50.7 
48.7 

46.7 
44.8 
43.1 
41.6 

40.1 
38.7 
37.5 
36.3 

35.2 
33.2 

31.3 



* Cone head sometimes called pan head. (Hoopes & Townsend, Phila., Pa.) 
f All Rivets larger than one inch are made to exact diameter. 

In rivet calculations, it is customary to disregard friction and to 
proportion rivets to the entire stress to be transmitted. They must 
be of sufficient size and number to resist shear and to afford such 
bearing area as not to cause distortion of the metal at the rivet holes. 

(Pocket Companion, Carnegie Steel Co.) 



109 



Digiti 



zed by G00gk 



Weight of Cone Head Rivets Per 100* 
Scant Diameter 



1 Length 
Under 


Diameter 




















Head 


M" 


A* 


H* 


tt* 


K* 


H* 


H" 


1' 


IK" 


IK" 


«:::::::: 


8.6 


11.9 


15.5 












t 


t 


9.3 


12.7 


16.5 




. . . . 








Exact 


Exact 




















Dia. 


Dia. 


1 


9.9 


13.6 


17.6 


22.4 


28.1 


34.5 










1H 


10.6 


14.4 


18.6 


23.6 


29.6 


36.3 










1H 


11.2 


15.2 


19.6 


24.9 


31.1 


38.1 


46 


65 






1H 


11.9 


16.1 


20.7 


26.1 


32.6 


39.8 


48 


68 


93 




1H 


12.5 


16.9 


21.7 


27.4 


34.1 


41.6 


50 


70 


96 


127 


\y% 


13.2 


17.7 


22.7 


28.6 


35.6 


43.4 


52 


73 


100 


132 


IK 

m 


13.8 


18.6 


23.8 


29.9 


37.1 


45.1 


54 


76 


103 


136 


14.5 


19.4 


24.8 


31.1 


38.6 


46.9 


56 


78 


107 


140 


2 


15.1 


20.2 


25.8 


32.4 


40.1 


48.7 


58 


81 


110 


145 


2M 


15.8 


21.0 


26.9 


33.7 


41.6 


50.5 


60 


84 


114 


149 


2H 


16.4 


21.9 


27.9 


34.9 


43.1 


52.2 


62 


87 


117 


153 


2H 


17.1 


22.7 


28.9 


36.2 


44.6 


54.0 


64 


89 


121 


158 


2J4 


17.8 


23.5 


30.0 


37.4 


46.1 


55.8 


66 


92 


124 


162 


2% 


18.4 


24.4 


31.0 


38.7 


47.6 


57.5 


68 


95 


128 


166 


»:::::::: 


19.1 


25.2 


32.0 


39.9 


49.1 


59.3 


70 


97 


132 


171 


19.7 


26.0 


33.1 


41.2 


50.6 


61.1 


72 


100 


135 


175 


3 


20.4 


26.9 


34.1 


42.5 


52.1 


62.8 


74 


103 


139 


179 


3Ji 


21.7 


2$. 5 


36.2 


45.0 


55.1 


66.4 


78 


108 


146 


188 


»:::::::: 


22.9 


30.2 


38.2 


47.5 


58.1 


69.9 


83 


114 


153 


197 


24.3 


31.9 


40.3 


50.0 


61.1 


73.4 


87 


119 


160 


205 


4 


25.6 


33.5 


42.4 


52.5. 


64.1 


77.0 


91 


124 


167 


214 


4K 


26.9 


35.2 


44.4 


55.0 


67.1 


80.5 


95 


130 


174 


223 


4** 

4k 


28.2 


36.9 


46.5 


57.5 


70.1 


84.0 


99 


135 


181 


232 


29.5 


38.5 


48.6 


60.0 


73.1 


87.6 


103 


141 


188 


240 


5 


30.8 


40.2 


50.6 


62.6 


76.1 


"91.1 


107 


146 


195 


249 


5H 


32.1 


41.9 


52.7 


65.1 


79.1 


94.6 


111 


151 


202 


258 


&K 


33.4 


43.5 


54.8 


67.6 


82.1 


98.2 


115 


157 


209 


266 


34.7 


45.2 


56.8 


70.1 


85.1 


101.7 


120 


162 


216 


275 


6 


36.0 


46.8 


58.9 


72.6 


88.1 


105.2 


124 


167 


223 


284 


6H 


38.7 


50.2 


63.0 


77.6 


94.1 


112.3 


132 


178 


237 


301 


7 


41.3 


53.5 


67.2 


82.7 


100.2 


119.4 


140 


189 


251 


319 


Weight of 






















Heads... 


4.7 


6.9 


9.3 


12.3 


16.1 


20.4 


26 


38 


54 


75 



* Cone head sometimes called pan head. (Hoopes & Townsend, Phila., Pa.) 
f All Rivets larger than one inch are made to exact diameter. 



Boiler Rivet Steel.— The Am. Soc. for Testing Materials states 
that the steel shall be made by the open hearth process. Chemical 
composition, manganese .3O-.60%, phosphorus not over .04%, sul- 
phur not over .045%. Tensile strength 45,000-60,000 lb. per sq. 
in., yield point minimum .5 tensile strength/elongation in 8 ins. mini- 



i per cent r 2 4 — but not to exceed 30%. 

* tens. str. 



110 



Digitized 



by Google 



SECTION III 
SHIPBUILDING MATERIALS 

IRON AND STEEL, NON-FERROUS METALS AND ALLOTS, 
.WOOD, MISCELLANEOUS NON-METALLIC MATERIALS 

IRON AND STEEL 
Steel is a compound of iron and carbon intermediate in com- 
position between cast and wrought iron, but having a higher spe- 
cific gravity than either. 

Per cent, of carbon Sp. gr. Properties 
Cast iron 5 to 2 7.2 not malleable 

nor temperable 
Steel 1.5 to .10 7.8 malleable and 

temperable 
Wrought iron 30 to .05 7.7 malleable, not 

temperable 
1 The principal methods of manufacture are the crucible process, 
the open hearth process, and the Bessemer. In the crucible, im- 
pure wrought iron or blister steel with carbon and a flux is fused in 
a sealed vessel which air cannot enter: the best tool steels are made 
thus. In the open hearth process, pig iron is melted, wrought 
iron scrap being added until the proper degree of carbonization 
is secured. In the Bessemer process, pig iron is completely decar- 
bonized in a converter by an air blast and then recarbonized to the 
proper degree by the addition of spiegeleisen. The metal for the 
open hearth or for the Bessemer converter is cast into ingots which 
are rolled in mills to the required forms. The open hearth pro- 
cess produces steel for shafts, axles, armor plate and for structural 
purposes, and the Bessemer process mainly produces steel for rail- 
road rail. [Mechanical Eng're Handbook, Kent.] 

The physical properties of* steel depend upon the method of man- 
ufacture and chemical composition, carbon being the controlling 
element in regard to strength, and the same is the case with respect 
to ultimate elongation. The higher the percentage of carbon 
within a reasonable limit the greater the strength and the less the 



112 SHIPBUILDING MATERIALS 

ultimate elongation. Steel may be given special properties by 
adding other elements as nickel, chromium, etc., in which case 
the steel is known as alloy or special steel, being given the name of 
the element added, as nickel steel, chromium steel, etc. 

Carbon Steel. — Here carbon is the controlling element. Carbon 
steel may be classified as follows: 

Soft, .05-.20% carbon not temperable, easily welded 

Medium, .15-40% carbon poor temper, weldable 
Hard, ,3O-.70% carbon temperable, welded with difficulty 
Very hard, .60-1% carbon high temper, not weldable 
Increasing the carbon content of steel increases its strength, 
hardness, brittleness, and susceptibility to cracking under sudden 
cooling or heating, it also diminishes the elongation and reduction 
of area to fracture. Phosphorus increases the tensile strength 
about 1,000 lb. per square inch for each .01% but tends to make the 
metal brittle. 

Average Properties op Steel in Pounds per Square Inch 

Medium Hard 

Elastic limit in tension and compression 35,000 50,000 

Elastic limit shear 30,000 40,000 

Tensile strength 60,000 100,000 

Compressive strength 60,000 * 120,000 

Shearing strength 50,000 75,000 

Modulus of rupture 110,000 

Modulus of elasticity, tension 30,000,000 30,000,000 

Modulus of elasticity, shear . 12,000,000 12,000,000 

Ultimate elongation ranges from 5 to 30%, the higher the amount 
of carbon the less the elongation. Reduction of area follows the 
game rule, ranging from 10 to 60%. Coefficient of expansion 
.0000065° F. Sp. gr. about 7.8. Weight per cu. ft. 490-491 lb. 

Manganese Steel. — Manganese increases the tensile strength 
from 80 to 400 lb. per square inch for each .01% depending on the 
carbon present and whether the steel is acid or basic. In its most 
serviceable form manganese steel contains about 13 to 14% of 
manganese and is practically non-magnetic. On account of its 
extreme hardness it is difficult to machine. 

The usual analysis of manganese steel lies between the following 
limits, manganese 11 to 14%, carbon 1. to 1.3%, silicon .3 to .8%, 
phosphorus .05 to .08%, the sulphur content being so as to be 
negligible. Manganese steel when tested in the form of a %-in. 

Digitized by VJiOOQ 1C 



NICKEL STEEL 



113 



round bar should show a tensile strength of 140,000 lb. per square 
inch, elastic limit 90,000, reduction of area not less than 50%, 
elongation in 2 ins. not less than 20%. Castings on cooling shrink 
to a noticeable extent, and an allowance of about & of an in. should 
be made per foot. 

Nickel Steel. — Ordinarily contains 1.5 to 4.5% of nickel and 
.2 to .5% of carbon. Nickel steel has a larger resistance to wear 
and abrasion than carbon steel and greater resistance to corrosion. 
When the percentage of nickel is less than 5%, the elastic limit 
and tensile strength are increased without any reduction in the 
elongation or in the contraction of area. Because of this increase 
in strength without loss of ductility nickel steel is used for shafting, 
connecting rods, etc., where a steel is required that will combine 
great strength and toughness. Tests made at the Watertown 
Arsenal (Watertown, Mass.) on a 3.37% nickel steel gave an aver- 
age elastic limit of 56,700 lb. per square inch and a tensile strength 
of 90,300. It is practically non-corrodible, and has a high electrical 
resistance which does not seem to vary much with the percentage 
of nickel. 



Compakison op Simple Steel and Nickel Steel Forgings 



Steel Forging 


Nickel Steel Forging 


Car- 
bon 


Tensile 
Strength 


Elastic 
Limit 


Elong- 
ation, 
% 


Reduc- 
tion of 
Area, 

% 


Car- 
bon 


Nick- 
el 


Tensile 
Strength 


Elastic 
Limit 


Elong- 
ation, 
% 


Reduc- 
tion of 
Area, 

% 


.20 
.30 
.40 
.50 


55,000 
75,000 
85,000 
95,000 


28,000 
37,000 
43,000 
48,000 


34 
30 
25 
21 


60 
50 
45 
40 


.20 
.30 
.40 
.50 


3.5 
3.5 
3.5 
3.5 


85,000 
95,000 
111,000 
125,000 


48,000 
60,000 
72,000 
85,000 


26 
22 
18 
13 


55 
48 
40 
32 



Nickel steel in the form of shapes, plates, or bars containing 
3.25% nickel has a tensile strength of 85,000-100,000 lb. per square 
inch, elastic limit 50,000, shearing % of the tensile strength, mod- 
ulus of elasticity 29,000,000, elongation 17.G-15%. Sp. gr. of low 
carbon nickel steel containing up to 15% nickel is from 7.86 to 
7.9 and from 19 to 39% is 7.91 to 8.08. 

Silicon Steel. — The addition of silicon to steel appears to in- 
crease the strength about 80 lb. per square inch for every .01% up 
to a content of 4%; beyond this it impairs the ductility. 

Tungsten Steel is characterized by hardness and toughness and 

Digitized by VJiOOQlC 



114 SHIPBUILDING MATERIALS 

its remarkable tempering properties. The tungsten content 
ranges from .5% in ordinarybar steel, 2 to 5% in finishing and in- 
termediate steels, 4.5 to 12% in self-hardening or air-hardening 
steels and 14 to 26% in high speed steels. 

Vanadium Steel. — The vanadium content is usually less than 
3%. Its effect is to improve the tensile strength, hardness and 
toughness. 

Chromium Steel. — Here the percentage of chromium varies 
from 2.5 to 5%, and of carbon from .8 to .2%. This steel is very 
hard and tough. Armor-piercing projectiles are made of it. 

Chromium-Nickel Steel. — The influence of both chromium and 
nickel is to increase the hardness and strength. Gears, axles, 
shafts, and gun barrels are made of it. 

Chromium-Vanadium Steel. — Particularly suitable for springs. 
Axles and gears are also made of this steel. 

Structural Steel. — This is carbon steel rolled into shapes and 
plates. Lloyd's rules state: "Steel for shipbuilding shall be made 
by the open hearth process, acid or basic. The tensile breaking 
strength of steel plates shall be between the limits of 28 and 32 
tons per square inch. Plates intended for cold flanging, the tensile 
strength shall be between 26 and 30 tons per square inch. The 
elongation measured on a standard test piece having a gauge length 
of 8 ins., shall not be less than 20% for material .375 inch in thick- 
ness and upwards, and not less than 16% for material below .375 
inch in thickness. The tensile strength of angles, channels, etc., 
shall be between 28 and 33 tons per square inch. The elongation 
on a standard test piece having a gauge length of 8 ins. shall not 
be less than 20% for material .375 inch in thickness and upwards, 
and not less than 16% for material below. For cold and temper 
tests the test pieces shall withstand without fracture, being doubled 
over until the internal radius is equal to 1^ times the thickness 
of the test piece and the sides are parallel." 

American Bureau of Shipping Rules state: "Steel plates, angles 
and shapes shall have an ultimate tensile strength of from 58,000 
to 68,000 lb. per square inch of 'section, an elastic limit of one- 
half the ultimate tensile strength, a reduction of area at point of 
fracture of at least 40% and an elongation of 22% in 8 ins. for plates 
18 lb. thick and over, and 18% for plates under 18 lb. Material 
of greater ultimate tensile strength than 68,000 lb. per square inch 
and not above 70,000 lb. may be accepted provided the elongation 
and reduction are as specified and the bending tests meet the re- 
Digitized by vjOOQ 1C 



BEND TESTS 115 

quirements. Shapes and angles in excess of 68,000 lb. tensile 
strength must be capable of being efficiently welded. Specimens 
for all materials (plates and shapes) must stand bending through 
180° on a radius of one-half its thickness without fracture on the 
convex side either cold or after being heated to cherry red and 
quenching in water at 80° F." 

Abstracts from the Specifications of Structural Steel for Ships, 
issued by the American Society for Testing Materials, are as follows: 
"The steel shall be made by the open hearth process and shall con- 
form to the following requirements as to chemical composition. 

_, , ( Acid not over .06% 

Phosphorus:^ . n .ir 

( Basic not over .04% 

Sulphur not over .05% 

"Tension Tests.— Tensile strength 58,000-68,000 lb. per square 

inch. 

Yield point maximum .5 tensuVstrength. 

1 500 000 

Elongation in 8 ins. minimum per cent. 7 r. — f -r 

tensile strength 

"For material over % inch in thickness, a deduction of one from 
the percentage of elongation as given above shall be made for 
each increase of J^ inch in thickness above % inch to a minimum 
of 18%. For material x /i inch or under in thickness the elongation 
shall be measured on a gauge length of 24 times the thickness of 
the specimen. 

"Bend Tests. — The test specimen shall bend cold through 180° 
without cracking on the outside of the bent portion as follows: 
For material % inch or under in thickness, around a pin the diam- 
eter of which is equal to the thickness of the specimen, for material 
over % inch to and including \ x /i inch in thickness around a pin 
the diameter of which is equal to \ l A times the thickness of the 
specimen, and for material over 1J^ inch in thickness around a 
pin the diameter of which is equal to twice the thickness of the 
specimen. 

"Test Specimens. — Tension and bend test specimens shall be 
taken from the finished rolled material. The specimens have a 
parallel section not less than 9 ins. long by \ X A ins. wide, broad- 
ened out at each end to about 2 ins. in width by about 3 ins. long, 
making approximately a total length of 18 ins. 

"Permissible Variations. — The cross section or weight of each 
piece of steel shall not vary more than 2.5% from that specified; 

Digitized by vjOOQ IC 



116 



SHIPBUILDING MATERIALS 



except in the case of sheared plates which shall be covered by the 
following permissible variations to apply to single plates. 

"When ordered to weight for plates 12 J^ lb. per square foot or 
over, under 100 ins. in width, 2.5% above or below the specified 







Allowable Excess, Expressed as Percentage of 




Nominal Weight, 
Lb. per Sq. Ft. 


Nominal Weight for 


Width of Plate as Follows: 


Thickness 
















Ordered, Ins. 




50 Ins. 






75 Ins. 


100 Ins. 


1151ns. 






Under 


to 70 


70 Ins. 


Under 


to 100 


to 115 


or 






50 Ins. 


Ins. 
Excl. 


Over 


75 Ins. 


Ins. 
Excl. 


Ins. 
Excl. 


Over 


Hto«/a 


5.10 to 6.37 


10 


15 


20 










•&* 


6.37 to 7.65 


8.5 


12.5 


17 










7.65 to 10.20 


7 


10 


15 












10.20 








10 


14 


18 




A 


12.75 








8 


12 


16 




7& 


15.30 








7 


10 


13 


17 


■ $ 


17.85 








6 


8 


10 


13 


20.40 








5 


7 


9 


12 


Over y* 


22.95 








4.5 


6.5 


8.5 


11 


25.50 








4 


6 


8 


10 










3.5 


5 


6.5 


9 



Principal Requirements for Steel and Iron for U. S. Naval 

Vessels 







Minimum Ten- 


Elongation 


Quality of 
Material 




sile Strength, 






Use 


Lb. per Square 










Inch 


Percent 


Ins. 


Medium steel, open 


Plates and shapes for 


60,000 


25 


8 


hearth, carbon. 


hull.' 








High tensile steel, 


Plates and shapes for 


80,000 


20 


8 


open hearth, car- 


hull. 








bon, nickel, or sil- 










icon. 










Medium steel, open 


Rods and bars for riv- 


<lHin.dia., 


28 


8 


hearth, carbon. 


ets, bolts, stanchions, 


=58,000 








davits, etc. 


>lHindia., 

60,000 
< 1H in. dia., 


30 


32 


High-tensile steel, 


Rods and bars for riv- 


23 


8 


open hearth, car- 


ets, bolts, stanchions, 


=75,000 






bon, nickel, or sil- 


davits, etc. 


>lHin.dia., 


25 


2 


icon. 




75,000 






Steel f orgings, Class 


Forgings exposed to 


80,000 


25 


2 


A, open hearth, 
nickel or carbon. 


dynamic actions as 








gun mounts. 








Steel f orgings, Class 


Stems and stern posts, 


60,000 


30 


2 


B, open hearth, 


rudder stocks, eto. 








carbon. 










Steel castings, Class 

A. 
Steel castings, Class 


Hawse pipes, turret 

tracks, etc. 
Stems, stern posts, rud- 


80,000 


17 


2 


60,000 to 80,000 


22 


2 


B. 


der frames, struts, 
etc. 








Wrought iron 


Miscellaneous forgings. 


48.000 




*Ir 8 








by VjUUJ 


ac 



RIVET STEEL 117 

weight; 100 ins. in width or over 5% above or below the specified 
weight. For plates under 12J£ lb., under 75 ins. in width 2.5% 
above or below the specified weight, 75 to 100 ins. exclusive in 
width 5% above or 3% below the specified weight, 100 ins. in 
width or over 10% above or 3% below the specified weight. 

"When ordered to gauge, the thickness of each plate shall not 
vary more than .01 inch under that ordered. An excess over the 
nominal weight corresponding to the dimensions on the order shall 
be allowed for each plate, if not more than that shown on the table 
given on page 116, one cubic inch of rolled steel being assumed to 
weigh .2833 lb." 

The ultimate strength of steel in tension and compression is 
practically the same, and may for different kinds of steel be assumed 
as follows: 



Kind of Steel 


Ultimate Strength, 
Pounds per Square Inch 


Structural steel for rivets 


55,000 
60,000 
50,000 
60,000 
75,000 
90,000 
100,000 
125,000 


Structural steel for beams 


Boiler steel for rivets 


Boiler steel for plates 


Machine steel 


Gun steel 


Axle steel 


Spring steel 



Rivet Steel. — Lloyd's requirements are: "The tensile strength 
of steel rivet bars shall be between the limits of 25 and 30 tons per 
square inch of section with an elongation of not less than 25% of 
the gauge length of eight times the diameter of the test piece." 

American Bureau of Shipping: "Materials for rivets shall be 
of best open hearth steel, limit of phosphorus and sulphur .04 of 
one per cent. Tensile strength to be not less than 45,000 nor 
more than 55,000 lb. per square inch." 

Abstracts from the Specifications for Rivet Steel for Ships issued 
by the American Society for Testing Materials are as follows: 
"The steel shall be made by the open hearth process and shall con- 
form to the requirements given below: 

„, , ( Acid not over .06% 

Phosphorus :•{„ . . n ,ir 

* ( Basic not over .04% 

Sul P hur • not over .045%, o M e 



118 SHIPBUILDING MATERIALS 

' ' Tension Tests.— Tensile strength 55,000-65,000 lb. per square inch. 
Yield point minimum, .5 tensile strength 

1,500,000 
Elongation in 8 ins. minimum per cent, tensile strength 

"For bars over % inch in diameter, a deduction of one from the 
percentage of elongation specified above shall be made for each 
increase of y% inch in diameter above % inch. 

"Bend Tests. — The test specimen shall bend cold through 180° 
flat on itself without cracking on the outside of the bent portion. 

"Flattening Tests. — The rivet head shall flatten while hot to 
a diameter of 2H times the diameter of the shank without crack- 
ing at the edges. 

"Permissible Variations. — The gauge of bars 1 in. or under in 
diameter shall not vary more than .01 inch from that specified; 
the gauge bars over 1 in. to and including 2 ins. in diameter shall 
not vary more than A under nor more than ^ inch over that 
specified." 

See also Rivets and Riveting. 

Cast Steel. — A malleable alloy of iron cast from a fluid mass. 
It is distinguished from cast iron which is not malleable by being 
much lower in carbon and from wrought iron by being free from 
intermingled slag. Stern frames, tillers, quadrants, gun mounts, 
etc., are made of it. 

Lloyd's rules state: "The tensile breaking strength determined 
from test pieces of standard dimensions is to be between 28 and 
35 tons per sq. in. with an elongation of not less than 20%. 
They must also stand being bent cold through an angle of 120°, 
the internal radius not being greater than one inch. The castings 
are also to be subjected to dropping and hammer tests." 

American Bureau of Shipping requirements are: "Tensile 
strength not less than 60,000 lb. per sq. in., elongation not less 
than 15% in 8 ins. For moving parts a bar one inch square 
shall bend cold through an angle of 120° over a radius not exceed- 
ing 1J^ ins. and without showing cracks or flaws. For other cast- 
ings, tests will be the same except that the angle may be reduced 
to 90°. Drop tests shall be made from a height not exceeding 
10 ft. on a hard road or floor." 

The following abstract is from the Specifications of Steel Cast- 
ings issued by the American Society for Testing Materials: "These 
specifications cover two classes of castings, viz., Class A ordinary 
castings for which no physical requirements are specified, and 

Digitized by vjOOQ 1C 



IKON 



119 



Class B for which requirements are specified. There are three 
grades in Class B, hard, medium and soft. 

"Chemical Composition. — 

Class A Class B 

Carbon not over .30% 

Phosphorus not over .06% 

Sulphur 

"Physical Properties. — 



not over .05% 
not over .05% 





Hard 


Medium 


Soft 


Tensile strength, lbs. per sq. in 


80,000 
36,000 

15 

20 


70,000 
31,500 

18 

25 


60,000 
27,000 


Yield, ooint, lbs. per sq. in 


Elongation in 2 ins., per cent 


22 


Reduction of area, per cent 


30 







"Bend Tests. — The test specimen for soft castings shall bend 
cold through 120°, and for medium castings through 90°, around 
a 1-inch pin, without cracking on the outside of the bent portion. 
Hard castings shall not be subject to bend test requirements. 

"Heat Treatment. — Class A castings need not be annealed 
unless otherwise specified. Class B shall be annealed, which con- 
sists in allowing the castings to become cold, and then uniformly 
reheating them to the proper temperature to refine the grain, and 
allowing them to cool uniformly and slowly. All castings for ships 
shall be annealed. 

"Percussion Test. — The casting is suspended by chains and 
hammered all over by a hammer of a weight approved by the pur- 
chaser. If cracks, flaws or weakness appear after such treatment 
the casting will be rejected." 

" Shrinkage allowed for casting about A of an inch per foot. 
Weight per cubic foot, 490 lb. Sp. gr. 7.8-7.9. 

Iron. — Iron plates and shapes for ships have been superseded 
by steel as the former are heavier for a given strength. Lloyd's 
states: "Deck plating and ordinary floors, also the floors, girders 
and top plating of double bottoms in holds, coal bunker and other 
bulkheads, shaft tunnels, casings around engines, hatchway 
coamings, bulwarks and deck houses may be of iron 10% in excess 
of the thicknesses in steel where scantlings for the same are pro- 
vided for in the Rules. No other parts of the vessel are to be of 
iron without the special sanation of the Committee." Pure iron 
has a tensile strength of 40,000 lb. and is very ductile. Weight 
per cubic foot 480 lb. Sp. gr. 7.70. 

Digitized by LiOOQ LC 



120 SHIPBUILDING MATERIALS 

Wrought Iron. — Is tough, ductile, malleable, weldable but can- 
not be tempered. Boat davits, rail stanchions and a variety of 
fittings are made of it. It is composed chiefly of pure iron and 
slag (iron silicate) and, in small amounts, the following impurities: 
Common wrought iron Best wrought iron. 

Carbon .05% .06% 

Phosphorus .35 .18 

Sulphur .06 .04 

Silicon .23 .20 

Manganese .... .06 

Siag about 3.3 2.80 

Tension. — Average of many tests at Columbia University, New 
York, on good wrought iron for general purposes: 

Elastic limit pounds per square inch 31,000 

Ultimate strength 51,000 

Elongation in 8 ins. per cent 21 

Reduction of area per cent. 30 

Modulus of elasticity pounds per square inch. . 28,200,000 
Shear and Torsion. — I^st wrought iron which had an ultimate 
tensile strength of 48,400 gave as follows: 

Ultimate strength in single shear pounds per 

square inch 42,000 

Elastic limit in torsion 20,530 

Ultimate strength 56,400 

Modulus of elasticity 12,800,000 

Compression. — Ultimate compressive strength of good wrought 
iron varies from 55,000 to 60,000 lb. per square inch. Elastic limit 
in compression is from 40 to 50% the ultimate strength. • Weight 
per cubic foot, 485 lb. Sp. gr. 7.6-7.9. 

(From Civil Engineer's Handbook, M. Merriman.) 

Cast Iron. — Is brittle, weak in tension and strong in compres- 
sion. Its great usefulness comes from the fact that it can be readily 
cast in a variety of forms. For engine cylinders hard close grain 
iron is called for. Cast iron when exposed to continued heat 
becomes permanently expanded lJi to 3% of its length, hence 
grate bars should be allowed about 4% play. 

Carbon, silicon and other impurities affect the physical properties. 
Carbon occurs as combined carbon or as a graphite or uncombined 
carbon. When the former the metal is hard, brittle, white, weak in 
tension and strong in compression, while in the latter (graphitic 

Digitized by VjOOQ 1C 



PICKLING AND GALVANIZING 121 

carbon) the iron is soft, gray, and weak in tension and compres- 
sion. Silicon in cast iron up to .5 % increases its compressive strength, 
and the tensile strength is increased up to 2%. Manganese when 
below 1 % is not injurious, but when above, it causes hardness and 
brittleness. Phosphorus makes the iron weaker and becomes a 
serious impurity when it occurs in quantities above 1.5%. Sulphur 
causes whiteness, brittleness, hardness and greater shrinkage, and 
is in general an objectionable impurity. 

Cast iron has an average tensile strength of 22,500 lb. per square 
inch, compression about 90,000, modulus of elasticity in tension 
varies from 15,000,000 to 20,000,000 lb. per square inch, and in 
shear 5,000,000 to 7,000,000. Weight per cubic foot, 449.2. Sp. 
gr. 6.85 to 7.4. 

Malleable Iron. — This is cast iron that has been heated to a 
temperature of about 2,000° F. The castings are packed in retorts 
or annealing pots and an oxide of iron (generally hematite ore) 
is packed with them. The castings are kept red hot for several 
days, causing the carbon near the surface to be burned out, leaving 
the outer surface tough and strong like wrought iron while the 
interior is hard. Pipe fittings largely are made of it. Tensile 
strength 37,000 lb. per square inch. 

Pickling and Galvanizing 

Pickling. — Steel plates as received from the mill have a scale 
which must be removed before they can be painted or cemented, 
otherwise when the scale falls off bare places will be left. The 
scale is removed by pickling, the plate being stood on end in a 
hydrochloric acid bath (19 parts water and 1 of acid), for about 
12 hours, then taken out and thoroughly washed with fresh water. 

Galvanizing. — Cast iron and wrought- iron fittings exposed to 
the weather or to dampness, and sometimes the steel frames and 
floors of torpedo boats and destroyers are galvanized. Before 
galvanizing all paint must be burned off and the fittings cleaned, 
after which they are placed in a bath of one part of hydrochloric 
acid and 40 parts of water to remove rust and grease. They are 
next dried and placed in a zinc bath from which they are taken 
after a sufficient coating of zinc has been deposited on them. The 
additional weight due to galvanizing by the hot process is 2J4 to 2 l A 
ounces and by the electric process about 1 ounce per square foot 
of exposed surface. All steel plates less than Y% of an inch thick 
should be galvanized before assembling. ^ r^r^Mo 

Digitized by vjitJOx L*~ 



122 



SHIPBUILDING MATERIALS 



The outward appearance of any galvanized article is not neces- 
sarily an indication of its excellence. The only final test of a 
zinc coating is the test of time under actual conditions of exposure. 
As this takes too long for commercial purposes, various tests have 
been devised; among them may be mentioned the lead acetate 
by Prof. W. H. Walker (Massachusetts Institute of Technology, 
Boston, Mass.). This test is designed to show the weight of actual 
coating covering products, and takes into consideration the im- 
purities in the coating. The solution employed removes from the 
articles both the zinc and zinc iron alloys present. The accurate 
weight before and after testing furnishes the basis for computing the 
quantitative value of the coating. The weighings must be accurate 
to one milligram. The length of time the sample is being tested 
is about 3 minutes. For further particulars see "Galvanizing 
and Tinning," by W. T. Flanders. 



Weights of Steel Plates 


in Hundredths of 


an Inch 




Weight in 




Weight in 


Thickness, Ins. 


Lb. per 

Sq. Ft. 


Thickness, Ins. 


Lb. per 
Sq. Ft. 


1 




55 




ioo 


.408 


loo 


22.44 


5 
100 


2.04 


60 
100 


24.48 


10 




65 




loo 


4.08 


loo 


26.52 


15 




70 




Too 


6.12 


loo 


28.56 


20 




75 




100 


8.10 


loo 


30.60 


25 
100 


io.20 


80 
100 


32.64 


30 




85 




loo 


12.24 


100 


34.68 


35 
100 


14.28 


90 
100 


36.72 


40 
100 


16.32 


95 
100 


38.76 


45 
100 


18.36 


100 
100 


40.80 


50 








loo 


20.40 







Google 



Standard Gauges 





Thickness in Decimals of an Inch 


Number 
of Gauge 


Birmingham 

Wire Gauge 

(B.w.g.) 


British 
Imperial 


United States 
Standard 


Brown 
and Sharpe 


Stu 
Ste 
Wi 


t>'s Washburn 
el and 
re Moen 


0000000 





.500 


.500 








000000 


.... 


.464 


.46875 








00000 




.432 


.4375 








0000 


.454 


.400 


.40625 


.46*" 




" .3938 


000 


.425 


.372 


.375 


.40964 




. .3625 


00 


.380 


.348 


.34375 


.3648 




. .3310 





.340 


.324 


.3125 


.32486 




. .3065 


1 


.300 


.300 


.28125 


.2893 


'.25 


17 .2830 


2 


.284 


.276 


.265625 


.25763 


.21 


L9 .2625 


3 


.259 


.252 


.25 


.22942 


.21 


12 .2437 


4 


.238 


.232 


.234375 


.20431 


.2( 


)7 .2253 


5 


.220 


.212 


.21875 


.18194 


.2( 


M .2070 


6 


.203 


.192 


.203125 


.16202 


.2( 


)1 .1920 


7 


.180 


.176 


.1875 


.14428 


.11 


)9 .1770 


8 


.165 


.160 


.171875 


.12849 


.11 


YI .1620 


9 


.148 


.144 


.15625 


.11443 


.11 


)4 .1483 


10 


.134 


.128 


.140625 


.10189 


.11 


)1 .1350 


11 


.120 


.116 


.125 


.090742 


.1* 


*8 .1205 


12 


.109 


.104 


.109375 


.080808 


.1* 


S5 .1055 


13 


.095 


.092 


.09375 


.071961 


.1* 


12 .0915 


14 


.083 


.080 


.078125 


.064084 


.1* 


*0 .0800 


15 


.072 


.072 


.0703125 


.057068 


A\ 


r8 .0720 


16 


.065 


.064 


.0625 


.05082 


.Vt 


!5 .0625 


17 


.058 


.056 


.05625 


.045257 


.Vt 


12 .0540 


18 


.049 


.048 


.05 


.040303 


A( 


18 .0475 


19 


.042 


.040 


.04375 


.03589 


At 


)4 .0410 | 


20 


.035 


.036 


.0375 


.031961 


.1( 


U .0348 


21 


.032 


.032 


.034375 


.028462 


.1* 


57 .03175 


22 


.028 


.028 


.03125 


.025347 


.1* 


55 .0286 


' 23 


.025 


.024 


.028125 


.022571 


M 


>3 .0258 


24 


.022 


.022 


.025 


.0201 


At 


51 .0230 


25 


.020 


.020 


.021875 


.0179 


A* 


t8 .0204 


26 


.018 


.018 


.01875 


.01594 


.1^ 


L6 .0181 


27 


.016 


.0164 


.0171875 


.014195 


.14 


13 .0173 


28 


.014 


.0148 


.015625 


.012641 


Ac 


$9 .0162 


29 


.013 


.0136 


.0140625 


.011257 


At 


$4 .0150 


30 


.012 


.0124 


.0125 


.010025 


a: 


17 .0140 


31 


.010 


.0116 


.0109375 


.008928 


.IS 


50 .0132 


32 


.009 


.0108 


.01015625 


.00795 


.11 


L5 .0128 


33 


.008 


.0100 


.009375 


.00708 


.11 


L2 .0118 


34 


.007 


.0092 


.008593 


.006304 


.11 


L0 .0104 


35 


.005 


.0084 


.007812 


.005614 


.1( 


)8 .0095 


36 


.004 


.0076 


.007031 


.005 


.1( 


)6 .0090 


37 




.0068 


.006640 


.004453 


.1( 


)3 


38 




.0060 


.00625 


.003965 


.1( 


)1 


39 


.... 






.003531 


.01 


)9 


40 








.003144 


.01 


)7 



123 



ioogle 



United States Standard Gauge for 
and Steel 



Sheet and Plate Iron 





Approximate Thick- 


Approximate Thick- 


Weight per Square 


Number of Gauge 


ness in Fractions 


ness in Decimal 


Foot in Pounds 




of an Inch 


Parts of an Inch 


Avoirdupois l 


0000000 


1/2 


.5 


20. 


000000 


15/32 


.46875 


18.75 


00000 


7/16 


.4375 


17.5 


0000 


13/32 


.40625 


16.25 


000 


3/8 


.375 


15. 


00 


11/32 


.34375 


13.75 





5/16 


.3125 


12.5 


1 


9/32 


.28125 


11.25 


2 


17/64 


.265625 


10.625 


3 


1/4 


.25 


10. 


4 


15/64 


.234375 


9.375 


5 


7/32 


.21875 


8.75 


6 


13/64 


.203125 


8.125 


7 


3/16 


.1875 


7.5 


8 


11/64 


.171875 


6.875 


9 


5/32 


.15625 


6.25 


10 


9/64 


.140625 


5.625 


11 


1/8 


.125 


5. 


12 


7/64 


.109375 


4.375 


13 


3/32 


.09375 


3.75 


14 


5/64 


.078125 


3.125 


15 


9/128 


.0703125 


2.8125 


16 


1/16 


.0625 


2.5 


17 


9/160 


.05625 


2.25 


18 


1/20 


.05 


2. 


19 


7/160 


.04375 


1.75 


20 


3/80 


.0375 


1.5 


21 


11/320 


.034375 


1.375 


22 


1/32 


.03125 


1.25 


23 


9/320 


.028125 


1.125 


24 


1/40 


.025 


1. 


25 


7/320 


.021875 


.S75 


26 


3/160 


.01875 


.75 


27 


11/640 


.0171875 


.6875 


28 


1/64 


.015625 


.625 


29 


9/640 


.0140625 


.5625 


30 


1/80 


.0125 


.5 


31 


7/640 


.0109375 


.4375 


32 


13/1280 


.01015625 


.40625 


33 


3/320 


.009375 


.375 



124 



Digiti 



zed by G00gk 



United States Standard Gauge for Sheet and Plate Iron 
. and Steel — Continued 





Appro ximateThick- 


Approximate Thick- 


Weight per Square 


Number of Gauge 


ness in Fractions 


ness in Decimal 


Foot in Pounds 




of an Inch 


Parts of an Inch 


Avoirdupois 1 


34 


11/1280 


.00859375 . 


.34375 


35 


5/640. 


.0078125 


.3125 


36 


9/1280 


.00703125 


.28125 


37 


17/2560 


.006640625 


.265625 


38 


1/160 


.00625 


.25 



On and after July first, eighteen hundred and ninety-three, the above and no 
other shall be used in determining duties and taxes levied by the United States of 
America on sheet and plate iron and steel. But this act shall not be construed to 
increase duties upon any article which may be imported. 

In the practical use and application of the standard gauge hereby established a 
variation of two and one-half per cent, either way, may be allowed. Approved 
March 3, 1893. • 

The weight of flat galvanized sheets is based on the weight of black sheets and 
two and one-half (2}$) ounces per square foot added for the increase caused by 
galvanising. 

1 This is based on a cubic foot of wrought iron weighing 480 lb. Steel would be 
about 2 per cent heavier. 



Diamond Checkered Plates for Engine and Boiler Room 

Floors 

(Carnegie Steel Co.) 



Thickness of 

Plate— Rib &* 

Above Plate 


Width and Length in Inches 


Weightper 

Square Foot 

in Pounds 


6*toll% # 


12* to 48' 


48H" to 00" 


% 


120 
120 
120 
120 
120 
120 


240 
240 
240 
240 
240 
180 


240 
240 
240 
240 
240 
240 


21.4 


A 


18.9 


y % 


16.3 


A 


13.8 


\i 


11.2 


A 


8.7 







Classification of Gauges. — Brown & Sharpe (B & S) = Amer- 
ican Wire Gauge (AWG); United States Standard Gauge (U S S G) ; 
Birmingham Wire Gauge (B W G) ; New British Standard (N B S) = 
British Imperial Wire Gauge (I W G) - British Standard Wire 
Gauge (S W G). 



Digiti 



zed by G00gk 



125 



Weights op Sheets and Plates of Steel, Copper and Brass 
(Birmingham Wire Gauge) 







Weight per Square Foot 


No. of 


Thickness 
in Inches 








Gauge 












Steel 


Copper 


Brass 


0000 


.454 


18.5232 


20.5662 


19.4312 


000 


.425 


17.3400 


19.2525 


18.1900 


00 


.380 


15.5040 


17.2140 


16.2640 





.340 


13.8720 


15.4020 


14.5520 


1 


.300 


12.2400 


13.5900 


12.8400 


2 


.284 


11.5872 


12.8652 


12.1552 


3 


.259 


10.5672 


11.7327 


11.0852 


4 


.238 


9.7104 


10.7814 


10.1864 


5 


.220 


8.9760 


9.9660 


9.4160 


6 


.203 


8.2824 


9.1959 


8.6884 


7 


.180 


7.3440 


8.1540 


7.7040 


8 


.165 


6.7320 


7.4745 


7.0620 


9 


.148 


6.0384 


6.7044 


6.3344 


10 


.134 


5.4672 


6.0702 


5.7352 


11 


.120 


4.8960 


, 5.4360 


5.1360 


12 


.109 


4.4472 


4.9377 


4.6652 


13 


.095 


3.8760 


4.3035 


4.0660 


14 


.083 


3.3864 


3.7599 


3.5524 


15 


.072 


2.9376 


3.2616 


3.0816 


16 


,065 


2.6520 


2.9445 


2.7820 


17 


.058 


2.3664 


2.6274 


2.4824 


18 


.049 


1.9992 


2.2197 


2.0972 


19 


.042 


1.7136 


1.9026 


1.7976 


20 


.035 


1.4280 


1.5855 


1.4980 


21 


.032 


1.3056 


1.4496 


1.3696 


22 


.028 


1.1424 


1.2684 


1.1984 


23 


.025 


1.0200 


1.1325 


1.0700 


24 


.022 


.8976 


.9966 


.9416 


25 


.020 


.8160 


.9060 


.8560 


26 


.018 


.7344 


.8154 


.7704 


27 


.016 


.6528 


.7248 


.6848 


28 


.014 


.5712 


.6342 


.5992 


29 


.013 


.5304 


.5889 


.5564 


30 


.012 


.4896 


.5436 


.5136 


31 


.010 


.4080 


.4530 


.4280 


32 


.009 


.3672 


.4077 


.3852 


33 


.008 


.3264 


.3624 


.3424 


34 


.007 


.2856 


.3171 


.2996 


35 


.005 


.2040 


.2265 


.2140 


36 


.004 


.1632 


.1812 


.1712 


Specific gra 
Weight of « 


vities 


7.85 


8.72 


8.24 


i cubic foot... 


489.6 


543.6 


513.6 


Weight of a 


cubic inch . . 


.2833 


^itizsS 146 


£[ e .2972 



126 



Weights of Sheets and Plates of Steel, Copper and Brass 
(American or Brown and Sharpe Gauge) 







Weight per Square Foot 


No. of 


Thickness 
in Inches 








Gauge 












Steel 


Copper 


Brass 


0000 


.460000 


18.7680 


20.8380 


19.6880 


000 


.409642 


16.7134 


18.5568 


17.5327 


00 


.364796 


14.8837 


16.5253 


15.6133 





.324861 


13.2543 


14.7162 


13.9041 


1 


.289297 


11.8033 


13.1052 


12.3819 


2 


.257627 


10.5112 


11.6705 


11.0264 


3 


.229423 


9.3605 


10.3929 


9.8193 


4 


.204307 


8.3357 


9.2551 


8.7443 


5 


.181940 


7.4232 


8.2419 


7.7870 


6 


.162023 


6.6105 


7.3396 


6.9346 


7 


.144285 


5.8868 


6.5361 


6.1754 


8 


.128490 


5.2424 


5.8206 


5.4994 


9 


.114423 


4.6685 


5.1834 


4.8973 


10 


.101897 


4.1574 


4.6159 


4.3612 


11 


.090742 


3.7023 


4.1106 


3.8838 


12 


.080808 


3.2970 


3.6606 


3.4586 


13 


.071962 


2.9360 


3.2599 


3.0800 


14 


.064084 


2.6146 


2.9030 


2.7428 


15 


.057068 


2.3284 


2.5852 


2.4425 


16 


.050821 


2.0735 


2.3022 


2.1751 


17 


.045257 


1.8465 


2.0501 


1.9370 


18 


.040303 


1.6444 


1 .8257 


1.7250 


19 


.035890 


1.4643 


1.6258 


1.5361 


20 


.031961 


1.3040 


1.4478 


1.3679 


21 


.028462 


1.1612 


1.2893 


1 .2182 


22 


.025346 


1.0341 


1.1482 


1.0848 


23 


.022572 


.92094 


1.0225 


.99608 


24 


.020101 


.82012 


.91058 


.86032 


25 


.017900 


.73032 


.81087 


.76612 


26 


.015941 


.65039 


.72213 


.68227 


27 


.014195 


.57916 


.64303 


.60755 


28 


.012641 


.51575 


.57264 


.54103 


29 


.011257 


.45929 


.50994 


.48180 


30 


.010025 


.40902 


.45413 


.42907 


31 


.008928 


.36426 


.40444 


.38212 


32 


.007950 


.32436 


.36014 


.34026 


33 


.007080 


.28886 


.32072 


.30302 


34 


.006305 


.25724 


.28562 


.26985 


35 


.005615 


.22909 


.25436 


.24032 


36 


.005000 


.20400 


.22650 


.21400 


37 


.004453 


.18168 


.20172 


.19059 


38 


.003965 


.16177 


.17961 


.16970 


39 


.003531 


.14406 


.15995 


.15113 


40 


.003144 


.12828 


.14242 


.13456 



127 



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128 



Digiti 



zed by G00gk 



Sizes and Weights of Structural Shapes. 

A = area of section in square inches 

y — distance from center of gravity to extreme fiber in inches 

/ = moment of inertia about line through center of gravity 

S — section modulus = — 

y 



r «= radius of gyration 



/? 



Dimensions in inches, or functions of inches 
Weights in pounds per foot. 

Shipbuilding Channels 
(Carnegie Steel Co.) 



L.^J 



2 



Depth 


Weight 


Area of 


Width 

of 
Flange, 
Inches 


Thick- 












Dis- 
tance 


of 


Per 


Action 


ness 


Axis 1-1 




Axis 2-2 


Chan- 
nel, 
Inches 


Foot 

in 

Pounds 


in 
Square 
Inches 


of 
Web, 
Inches 












X 

for Axis 


/ 


8 


R 


/ 


8 


R 


2-2 
Inches 


13 


55.0 


16.17 


4.529 


0.904 


334.5 


51.5 


4.55 


18.1 


5.2 


1.06 


1.00 




50. 


14.71 


4.416 


.791 


313.8 


48.3 


4.62 


16.7 


4.9 


1.07 


.98 




45. 


13.24 


4.303 


.678 


293.1 


45.1 


4.71 


15.3 


4.6 


1.08 


.97 




40. 


11.76 


4.190 


.565 


272.3 


41.9 


4.81 


13.9 


4.3 


1.09 


.97 




37. 


10.88 


4.122 


.497 


259.9 


40. 


4.89 


13.1 


4.2 


1.10 


.98 




35. 


10.29 


4.077 


.452 


251.6 


38.7 


4.95 


12.5 


4.1 


1.10 


.99 




32. 


9.30 


4.000 


.375 


237.6 


36.6 


5.06 


11.6 


3.9 


1.12 


1.01 


12 


50. 


14.70 


4.140 


.840 


268.6 


44 .'8 


4.27 


17.8 


5.8 


1.10 


1.06 




48.4 


14.22 


4.100 


.800 


262.8 


43.8 


4.30 


17.3 


5.7 


1.10 


1.05 




46.3 


13.62 


4.050 


.750 


255.6 


42.6 


4.33 


16.6 


5.5 


1.11 


1.05 




44.3 


13.02 


4.000 


.700 


248.4 


41.4 


4.37 


16.0 


5.4 


1.11 


1.05 




40. 


11.76 


3.895 


.595 


233.3 


38.9 


4.45 


14.6 


5.1 


1.11 


1.05 




35. 


10.30 


3.773 


.473 


215.8 


36. 


4.58 


13.0 


4.8 


1.12 


1.07 , 




40.8 


12.00 


3.700 


.700 


217.9 


36.3 


4.26 


11.3 


4. 


.97 


.89 




37.2 


10.92 


3.610 


.610 


205.0 


34.2 


4.33 


10.4 


3.8 


.98 


.89 




32.7 


9.60 


3.500 


.500 


189.1 


31.5 


4.44 


9.4 


3.6 


.99 


.89 




30.2 


8.88 


3.440 


.440 


180.5 


30.1 


4.51 


8.8 


3.5 


.99 


.90 


10 


40. 


11.77 


4.091 


.741 


157.1 


31.4 


3.65 


15.4 


5.2 


1.14 


1.11 




36.9 


10.86 


4.000 


.650 


149.5 


29.9 


3.71 


14.3 


4.9 


1.15 


1.11 




34.4 


10.11 


3.925 


.575 


143.2 


28.6 


3.76 


13.4 


4.8 


1.15 


Lll^T^ 




31.8 


9.36 


3.860 


.500 


137.0 


27.4 


3.83 


12.4 


4.6 


1.15 


1.13 



129 



r 



Shipbuilding Channels— Continued 























Dis- 


Depth 
of 


Weight 
Per 


Area of 
Action 


Width 


Thick- 
ness 


Axis 1-1 




Axis 2-2 


tance 

X 


Chan- 


Foot 
in 


in 
Square 


of 

Flange, 

Inches 


of 
Web, 












forAxis 


nel, 














2-2 


Inches 


Pounds 


Inches 


Inches 


/ 


S 


R 


/ 


S 


R 


Inches 




30.0 


8.83 


3.797 


.447 


132.6 


26.5 


3.88 


11.7 


4.4 


1.15 


1.14 




32.2 


9.75 


3.675 


.675 


124.0 


24.8 


3.57 


9.1 


3.3 


.97. 


.89 




30.6 


9.00 


3.600 


.600 


117.7 


23.5 


3.62 


8.5 


3.1 


.97 


.88 




28.9 


8.50 


3.550 


.550 


113.6 


22.7 


3.66 


8.2 


3.1 


.98 


.88 




27.2 


8.00 


3.500 


.500 


109.4 


21.9 


3.70 


.78 


3. 


.99 


.89 




26.4 


7.75 


3.475 


.475 


107.3 


21.5 


3.72 


7.6 


2.9 


.99 


.89 




28.5 


8.38 


3.575 


.575 


108.0 


21.6 


3.58 


7.7 


2.8 


.96 


.84 




26.0 


7.63 


3.500 


.500 


101.7 


20.3 


3.65 


7.1 


2.7 


.97 


• 84. 




24.3 


7.13 


3.450 


.450 


97.5 


19.5 


3.70 


6.8 


2.6 


.97 


.85 




22.6 


6.63 


3.400 


.400 


93.4 


18.7 


3.75 


6.4 


2.5 


.98 


.86 




21.7 


6.38 


3.375 


.375 


91.3 


18.3 


3.78 


6.2 


2.5 


.99 


.87 


9 


35.5 


10.43 


4.025 


.675 


117.0 


26. 


3.35 


14.1 


4.9 


1.16 


1.16 




34.7 


10.21 


4.000 


.650 
.550 


115.6 


25.7 


3.36 


13.8 


4.9 


1.16 


1.16 




31.7 


9.31 


3.900 


109.5 


24.3 


3.43 


12.6 


4.6 


1.16 


1.17 




28.6 


8.41 


3.800 


.450 


103.4 


23. 


3.51 


11.4 


4.4 


1.16 


1.19 


8 


27.2 


8.00 


3.625 


.625 


68.9 


17.2 


2.94 


8.4 


3.2 


1.02 


.98 




26.5 


7.80 


3.600 


.600 


67.8 


17. 


2.95 


8.2 


3.1 


1.03 


.98 




25.2 


7.40 


3.550 


.550 


65.7- 


16.4 


2.98 


7.8 


3. 


1.03 


.98 




23.8 


7.00 


3.500 


.500 


63.6 


15.9 


3.01 


7.4 


3. 


1.03 


.99 




21.5 


6.32 


3.415 


.415 


60.0 


15. 


3.08 


6.9 


2.9 


1.05 


.99 




21.0 


6.16 


3.000 


.469 


54.1 


13.5 


2.96 


4.3 


1.9 


.83 


.79 




17.6 


5.16 


2.875 


.344 


48.8 


12.2 


3.07 


2.8 


1.3 


.74 


.80 


7 


24.5 


7.20 


3.600 


.600 


48.9 


14. 


2.61 


7.9 


3.1 


1.05 


1.04 




23.3 


6.85 


3.550 


.650 


47.5 


13.6 


2.63 


7.5 


3. 


1.05- 


1.04 




22.1 


6.50 


3.500 


.500 


46.0 


13.2 


2.66 


7.1 


2.9 


1.05 


1.05 




20.9 


6.15 


3.450 


.450 


44.6 


12.7 


2.69 


6.7 


2.8 


1.05 


1.05 




19.7 


5.80 


3.400 


.400 


43.2 


12.3 


2.73 


6.3 


2.7 


1.05 


1.07 




21.9 


6.43 


3.575 


.575 


42.6 


12.2 


2.57 


6.5 


2.5 


1.01 


.99 




18.6 


5.46 


3.438 


.438 


38.7 


11. 


2.66 


5.7 


2.3 


1.02 


.96 




16.5 


4.85 


3.350 


.350 


36.2 


10.3 


2.73 


5.1 


2.2 


1.03 


.99 




15.6 


4.59 


3.313 


.313 


36.1 


10. 


2.77 


4.8 


2.1 


1.03 


1.01 


6 


21.5 


6.33 


3.685' 


• .535 


33.3 


11.1 


2.29 


7.8 


3.1 


1.11 


1.16 




19.0 


5.58 


3.560 


.410 


31.1 


10.4 


2.36 


6.8 


2.9 


1.10 


1.18 




15.0 


4.46 


3.500 


.350 


25.0 


8.3 


2.37 


5.2 


2.1 


1.08 


1.08 




18.1 


5.33 


3.063 


.563 


25.4 


8.5 


2.18 


3.5 


1.6 


.82 


.80 




13.0 


3.83 


2*813 


.313 


20.9 


7. 


2.34 


2.6 


1.3 


.82 


.81 




17.0 


4.97 


2.781 


.531 


23.5 


7.8 


2.18 


2.8 


1.3 


.77 


.73 




12.5 


3.66 


2.563 


.313 


19 6 


6.5 


2.31 


2.1 


1.1 


.75 


.74 


Wt 


17.0 


4.99' 


3.500 


.375 


25.8 


9. 


2.28 


5.8 


2.5 


1.08 


1.15 


4 


13.6 


4.00 


2.500 


.500 


8.8 


4.4 


1.49 


2.2 


1.4 


.74 


.87 




6.4 


1.86 


.875 


.375 


3.2 


1.6 


1.31 


.08 


.13 


.21 


.27 


3 


7.1 


2.05 


1.984 


.250 


2.8 


1.9 


1.17 


.75 


.60 


.60 


.72 



Ordering Shapes and Plates. — Structural beams, H beams, 
structural channels, shipbuilding channels, bulb angles, bulb beams, 
Tees and Zees should be ordered to weight per foot. Angles may 
be ordered either to weight per foot or to thickness. 

Orders for rounds, squares and other bar mill products should 
specify width and thickness in inches and the length in feet and 
inches. 
, Orders for plates should specify all dimensions in inches. 

In the calculation of the areas and weights of the sections on the 
following pages, the fillets have been disregarded in accordance with 
the rules of the Association of American Steel Manufacturers. 

DigitizedbyVj VJVJYIC 




Size, Inches 




Weight 

*£ot 
Pounds 



56.9 
54.0 
51.0 
48.1 
45.0 
42.0 
38.9 
35.8 
32.7 
29.6 
26.4 
37.4 
35.3 
33.1 
31.0 
28.7 
26.5 
24.2 
21.9 
19.6 
17.2 
14.9 
30.6 
28.9 
27.2 
25.4 
23.6 
21.8 
20.0 
18.1 
16.2 
14.3 
12.3 
19.9 
18.5 
17.1 
15.7 
14.3 
12.8 
11.3 
9.8 
8.2 
6.6 
17.1 
16.0 
14.8 
13.6 
12.4 



Area of 
Section, 
Sq. Ins. 



16.73 
15.87 
15.00 
14.12 
13.23 
12.34 
11.44 
10.53 
9.61 
8.68 
7.75 
11.00 
10.37 
9.73 
9.09 
8.44 
7.78 
7.11 
6.43 
5.75 
5.06 
4.36 
9.00 
8.50 
7.98 
7.47 
6.94 
6.40 
5.86 
5.31 
4.75 
4.18 
3.61 
5.84 
5.44 
5.03 
4.61 
4.18 
3.75 
3.31 
2.86 
2.40 
1.94 
5.03 
4.69 
4.34 
3.98 
3.62 



Axis 1-1 and Axis 2-2 



98.0 

93.5 

89.0 

84.3 

79.6 

74.7 

69.7 

64.6 

59.4 

54.1 

48.6 

35.5 

33.7 

31.9 

30.1 

28.2 

26.2 

24.2 

22.1 

19.9 

17.7 

15.4 

19.6 

18.7 

17.8 

16.8 

15.7 

14.7 

13.6 

12.4 

11.3 

10.0 

8.7 

8.1 

7.7 

7.2 

6.7 

6.1 

5.6 

5.0 

4.4 

3.7 

3.0 

5.3 

5.0 

4.7 

4.3 

4.0 



2.42 
2.43 
2.44 
2.44 
2.45 
2.46 
2.47 
2.48 
2.49 
2.50 
2.51 
1.80 
1.80 
1.81 
1.82 
1.83 
1.83 
1.84 
1.85 
1.86 
1.87 
1.88 
1.48 
1.48 
1.49 
1.50 
1.50 
1.51 
1.52 
1.53 
1.54 
1.55 
1.56 
1.18 
1.19 
1.19 
1.20 
1.21 
1.22 
1.23 
1.23 
1.24 
1.25 
1.02 
1.03 
1.04 
1.04 
1.05 



17.5 
16.7 
15.8 
14.9 
14.0 
13.1 
12.2 
11.2 
10.3 
9.3 
8.4 
8.6 
8.1 
7.6 
7.2 
6.7 
6.2 
5.7 
5.1 
4.6 
4.1 
3.5 
5.8 
5.5 
5.2 
4.9 
4.5 
4.2 
3.9 
3.5 
3.2 
2.8 
2.4 
3.0 
2.8 
2.6 
2.4 
2.2 
2.0 
1.8 
1.5 
1.3 
1.0 
2.3 
2.1 
2.0 
1.8 
1.6 



2.41 
2.39 
2.37 
2.34 
2.32 
2.30 
2.28 
2.25 
2.23 
2.21 
2.19 
1.86 
1.84 
1.82 
1.80 
1.78 
1.75 
1.73 
1.71 
1.68 
1.66 
1.64 
1.61 
1.59 
1.57 
1.55 
1.52 
1.50 
1.48 
1.46 
1.43 
1.41 
1.39 
1.29 
1.27 
1.25 
1.23 
1.21 
1.18 
1.16 
1.14 
1.12 
1.09 
1.17 
1.15 
1.12 
1.10 
1.08 



131 



y Google 



Equal Angles — Continued 





Weight 


Area of 


Axis 1-1 and Axis 2-2 


Site, Inches 


Foot 


Section 
Sq. Ins. 




















Pounds 


A 


I 


R 


S 


X 


3HX8HX H 


11.1 


3.25 


3.6 


1.06 


1.5 


1.06 


ft:::::: 


9.8 


2.87 


3.3 


1.07 


1.3 


1.04 


8.5 


2.48 


2.9 


1.07 


1.2 


1.01 


ft:::::: 


7.2 


2.09 


2.5 


1.08 


.98 


.99 


5.8 


1.69 


2.0 


1.09 


.79 


.97 


3* X 34 X ^ . 


11.5 
10.4 
9.4 
8.3 
7.2 
6.1 
4.9 
7.7 


3.36 
3.06 
2.75 
2.43 
2.11 
1.78 
1.44 
2.25 


2.6 
2.4 
2.2 
2.0 
1.8 
1.5 
1.2 
1.2 


.88 
.89 
.90 
.91 
.91 
.92 
.93 
.74 


1.3 

1.2 

1.1 
.95 
.83 
.71 
.58 
.73 


.98 




.95 


15 


.93 


■rir 


.91 


£| 


.89 


A 


.87 


H.;..: 


.84 


2H X 2M X H 


.81 


ft::::::" 


6.8 


2.00 


1.1 


.75 


.65 


.78 


5.9 


1.73 


.98 


.75 


.57 


.76 


£::;::: 


5.0 


1.47 


.85 


.76 


.48 


.74 


4.1 


1.19 


.70 


.77 


.39 


.72 


A:::::: 


3.07 


.90 


.55 


.78 


.30 


.69 


2.08 


.61 


.38 


.79 


.20 


.67 


2 X 2 X A- 


5.3 

4.7 

3.92 

3.19 

2.44 

1.66 

4.6 


1.56 

1.36 

1.15 

.94 

.71 

.48 

1.34 


.54 
.48 
.42 
.35 
.28 
.19 
.35 


.59 
.59 
.60 
.61 
.62 
.63 
.51 


.40 
.35 
.30 
.25 
.19 
.13 
.30 


.66 


A A g 


.64 


A . ". 


.61 


g 


.59 


*..... 


.57 


#::::: 


.55 


IX X IH X A 


.59 


3.99 


1.17 


.31 


.51 


.26 


.57 


ft:::::: 


3.39 


1.00 


.27 


.52 


.23 


.55 


2.77 


.81 


.23 


.53 


.19 


.53 


ft:::::: 


2.12 


.62 


.18 


.54 


.14 


.51 


1.44 


.42 


.13 


.55 


.10 


.48 


W X W X H 


3.35 


.98 


.19 


.44 


.19 


.51 


ft:::::: 


2.86 


.84 


.16 


.44 


.16 


.49 


2.34 


.69 


.14 


.45 


.13 


.47 


ft:::::: 


1.80 


.53 


.11 


.46 


.10 


.44 


1.23 


.36 


.08 


.46 


.07 


.42 


1HXIH X p 


2.33 


.68 


.09 


.36 


.11 


.42 


1.92 


.56 


.08 


.37 


.09 


.40 


&::::: 


1.48 


.43 


.06 


.38 


.07 


.38 


1.01 


.30 


.04 


.38 


.05 


.35 


1 X 1 XW 


1.49 


.44 


.04 


.29 


.06 


.34 


A 


1.16 
.80 


.34 
.23 


.03 
.02 


.30 
.31 


.04 
.03 


.32 


5::::::.:.. 


.30 







Stove Bolts.*— Have either button or flush head similar to ordi- 
nary wood screws, but have threads for nut at end. 

Dia. of bolt, in. V % A A A l A A % 
Threads per in. 32 28 24 22 18 18 16 

Carriage Bolts. — Have button heads, and below is a square shank 
at end of which are threads for a nut. 

Diameter of bolt, in. KA^A^A^Ji^ 1 
Thickness of head, in. H AAAMAA^A^ 
Diameter of head, in. % % U % 1 W% IH Wt 1% 2 

The length of thread depends on the length of the bolt, the thread 
being about three times the thickness of the nut. See Table of Bolts 
and Nuts. 



132 



Digiti 



zed by G00gle 



Unequal Angles 








Weight 


Area of 




Axis 1-1 


Alia 2-2 




Sue, Inches 


Foot 


Section 
Sq.Ins. 






























Pounds 


A 


/ 


8 


B 


■ 


1 


5 


ft 


V 


8X6X1 ... 


44.2 


13.00 


80.8 


15.1 


2.49 


2.65 


38.8 


8.9 


1.73 


1.65 


H.... 


41.7 


12.25 


76.6 


14.3 


2.50 


2.63 


36.8 


8.4 


1.73 


1.63 


y& . . . . 


39.1 


11.48 


72.3 


13.4 


2.51 


2.61 


34.9 


7.9 


1.74 


1.61 


+| •• • • 


36.5 


10.72 


67.9 


12.5 


2.52 


2.59 


32.8 


74 


1.75 


1.59 


££.. . . 


33.8 


9.94 


63.4 


11.7 


2.53 


2.56 


30.7 


69 


1.76 


1.56 


if... 


31.2 


9.15 


58.8 


10.8 


2.54 


2.54 


28.6 


6.4 


1.77 


1.54 


». . 


28.5 


8.36 


54.1 


9.9 


2.54 


2.52 


26.3 


5.9 


1.77 


1.52 


A... 


25.7 


7.56 


49.3 


8.9 


2.55 


2.50 


24.0 


5.3 


1.78 


1.50 


i . 


23.0 


6.75 


44.3 


8.0 


2.56 


2.47 


21.7 


4.8 


1.79 


1.47 


v :::: 


20.2 


5.93 


39.2 


7.1 


2.57 


2.45 


19.3 


4.2 


1.80 


1.45 


8X3MX1 .. 


35.7 


10.50 


66.2 


13.7 


2.51 


3.17 


7.8 


3.0 


.86 


.92 


g:: 


33.7 


9.90 


62.9 


12.9 


2.52 


3.14 


7.4 


2.9 


.87 


.89 


31.7 


9.30 


59.4 


12.2 


2.53 


3.12 


7.1 


2.7 


.87 


.87 


»-. 


29.6 


8.68 


55.9 


11.4 


2.54 


3.10 


6.7 


2.5 


.88 


.85 


k- 


27.5 


8.06 


52.3 


10.6 


2.55 


3.07 


6.3 


2.3 


.88 


.82 


H-. 


25.3 


7.43 


48.5 


9.8 


2.56 


3.05 


5.9 


2.2 


.89 


.80 


*.. 


23.2 


6.80 


44.7 


9.0 


2.57 


3.03 


5.4 


2.0 


.90 


.78 


A- 


21.0 


6.15 


40.8 


8.2 


2.57 


3.00 


5.0 


1.8 


.90 


.75 


H- 


18.7 


5.50 


36.7 


7.3 


2.58 


2.98 


4.5 


1.6 


.91 


.73 


A- 


16.5 


4.84 


32.5 


6.4 


2.59 


2.95 


4.1 


1.5 


.92 


.70 


7X3HX1 .. 


32.3 


9.50 


45.4 


10.6 


2.19 


2.71 


7.5 


3.0 


.89 


.96 


S :: 


30.5 


8.97 


43.1 


10.0 


2.19 


2.69 


7.2 


2.8 


.89 


.94 


28.7 


8.42 


40.8 


9.4 


2.20 


2.66 


6.8 


2.6 


.90 


.91 


«.. 


26.8 


7.87 


38.4 


8.8 


2.21 


2.64 


6.5 


2.5 


.91 


.89 


«.. 


24.9 


7.31 


36.0 


8.2 


2.22 


2.62 


6.1 


2.3 


.91 


.87 


«.. 


23.0 


6.75 


33.5 


7.6 


2.23 


2.60 


5.7 


2.1 


.92 


.85 


N- 


21.0 


6.17 


30.9 


7.0 


2.24 


2.57 


5.3 


2.0 


.93 


.82 


A. 


19.1 


5.59 


28.2 


6.3 


2.25 


2.55 


4.9 


1.8 


.93 


.80 


«.. 


17.0 


5.00 


25.4 


5.7 


2.25 


2.53 


4.4 


1.6 


.94 


.78 


ft:: 


15.0 


4.40 


22.6 


5.0 


2.26 


2.50 


4.0 


1.4 


.95 


.75 


13.0 


3.80 


19.6 


4.3 


2.27 


2.48 


3.5 


1.3 


.96 


.73 


6X4X1 .... 


30.6 


9.00- 


30.8 


8.0 


1.85 


2.17 


10.8 


3.8 


1.09 


1.17 


8-- : 


28.9 


8.50 


29.3 


7.6 


1.86 


2.14 


10.3 


3.6 


1.10 


1.14 


27.2 


7.98 


27.7 


7.2 


1.86 


2.12 


9.8 


3.4 


1.11 


1.12 


«.... 


25.4 


7.47 


26.1 


6.7 


1.87 


2.10 


9.2 


3.2 


1.11 


1.10 


8.... 


23.6 


6.94 


24.5 


6.2 


1.88 


2.08 


8.7 


3.0 


1.12 


1.08 


«.... 


21.8 


6.40 


22.8 


5.8 


1.89 


2.06 


8.1 


2.8 


1.13 


1.06 


«.... 


20.0 


5.86 


21.1 


5.3 


1.90 


2.03 


7.5 


2.5 


1.13 


1.03 


A-.. 


18.1 


5.31 


19.3 


4.8 


1.90 


2.01 


6.9 


2.3 


1.14 


1.01 


H- ... 


16.2 


4.75 


17.4 


4.3 


1.91 


1.99 


6.3 


2.1 


1.15 


.99 


A.... 


14.3 


4.18 


15.5 


3.8 


1.92 


1.96 


5.6 


1.8 


1.16 


.96 


N-... 


12.3 


3.61 


13.5 


3.3 


1.93 


1.94 


4.9 


1.6 


1.17 


.94 


6X3HX1 .. 


28.9 


8.50 


29.2 


7.8 


1.85 


2.26 


7.2 


2.9 


.92 


1.01 


1: 


27.3 


8.03 


27.8 


7.4 


1.86 


2.24 


6.9 


2.7 


.93 


.99 


25.7 


7.55 


26.4 


7.0 


1.87 


2.22 


6.6 


2.6 


.93 


.07 


24.0 


7.06 


24.9 


6.6 


1.88 


2.20 


6.2 


2.4 


.94 


.95 



133 



Unequal Angles — Continued 





Weight 


Area of 




Axial-l 






Axis 2-2 




Size, Inches 


per 
Foot 


Section 
Sq. Ins., 


































Pounds 


A 


/ 


S 


R 


X 


/ 


8 


R 


y 


6 X3M X %.. 


22 4 


6.56 


23.3 


6.1 


1.89 


2.18 


5.8 


2.3 


.94 


.93 


«•• 


20.6 


6.06 


21.7 


5.6 


1.89 


2.15 


5.5 


2.1 


.95 


.90 


• %.. 


18.9 


.5.55 


20.1 


5.2 


1.90 


2.13 


5.1 


1.9 


.96 


.88 


ft.. 


17.1 


5.03 


18.4 


4.7 


1.91 


2.11 


4.7 


1.8 


.96 


.86 


**.. 


15.3 


4.50 


16.6 


4.2 


1.92 


2.08 


4.3 


1.6 


.97 


.83 


fc: 


13.5 


3.97 


14.8 


3.7 


1.93 


2.06 


3.8 


1.4 


.98 


.81 


11.7 


3.42 


12.9 


3.3 


1.94 


2.04 


3.3 


1.2 


.99 


.79 


ft.- 


9.8 


2.87 


10.9 


2.7 


1.95 


2.01 


2.9 


1.0 


1.00 


.76 


5X4X %.... 


24.2 


7.11 


16.4 


5.0 


1.52 


1.71 


9.2 


3.3 


1.14 


1.21 


if.... 


22 7 


6.65 


15.5 


4.7 


1.53 


1.68 


8.7 


3.1 


1.15 


1.18 


&.... 


2l!l 


6.19 


14.6 


4.4 


1.54 


1.66 


8.2 


2.9 


1.15 


1.16 


8:::: 


19.5 


5.72 


13.6 


4.1 


1.54 


1.64 


7.7 


2.7 


1.16 


1.14 


17.8 


5.23 


12.6 


3.7 


1.55 


1.62 


7.1 


2.5 


1.17 


1.12 


ft.... 


16.2 


4.75 


11.6 


3.4 


1.56 


1.60 


6.6 


2.3 


1.18 


1.10 


M-... 


14.5 


4.25 


10.5 


3.1 


1.57 


1.57 


6.0 


2.0 


1.18 


1.07 


ft:::: 

5X3HXK-.. 


12.8 


3.75 


9.3 


2.7 


1.58 


1.55 


5.3 


1.8 


1.19 


1.05 


11.0 


3.23 


8.1 


2.3 


1.59 


1.53 


4.7 


1.6 


1.20 


1.03 


22.7 


6.67 


15.7 


4.9 


1.53 


1.79 


6.2 


2.5 


.96 


1.04 


tt... 


21.3 


6.25 


14.8 


4.6 


1.54 


1.77 


5.9 


2.4 


.97 


1.02 


X... 


19.8 


5.81 


13.9 


4.3 


1.55 


1.75 


5.6 


2.2 


.98 


1.00 


8::: 


18.3 


5.37 


13.0 


4.0 


1.56 


1.72 


5.2 


2.1 


.98 


.97 


16.8 


4.92 


12.0 


3.7 


1.56 


1.70 


4.8 


1.9 


.99 


.95 


S::: 


15.2 


4.47 


11.0 


3.3 


1.57 


1.68 


4.4 


1.7 


1.00 


.93 


13.6 


4.00 


10.0 


3.0 


1.58 


1.66 


4.0 


1.6 


1.01 


.91 


ft... 


12.0 


3.53 


8.9 


2.6 


1.59 


1.63 


3.6 


1.4 


1.01 


.88 


M-- 


10.4 


3.05 


7.8 


2.3 


1.60 


1.61 


3.2. 


1.2 


1.02 


.86 


ft... 


8.7 


2.56 


6.6 


1.9 


1.61 


1.59 


2.7 


1.0 


1.03 


.84 


5X3Xfl 


19.9 


5.84 


14.0 


, 4.5 


1.55 


1.86 


3.7 


1.7 


.80 


.86 


H 


18.5 


5.44 


13.2 


4.2 


1.55 


1.84 


3.5 


1.6 


.80 


.84 


it 


17.1 


5.03 


12.3 


3.9 


1.56 


1.82 


3.3 


1.5 


.81 


.82 


^ 


15.7 


4.61 


11.4 


3.5 


1.57 


1.80 


3.1 


1.4 


.81 


.80 


ft 


14.3 


4.18 


10.4 


3.2 


1.58 


1.77 


2.8 


1.3 


.82 


.77 


M 


12.8 


3.75 


9.5 


2.9 


1.59 


1.75 


2.6 


1.1 


.83 


.75 


ft 


11.3 


3.31 


8.4 


2.6 


1.60 


1.73 


2.3 


1.0 


.84 


73 


Vs 


9.8 


2.86 


7.4 


2.2 


1.61 


1.70 


2.0 


.89 


.84 


.70 


ft 


8.2 


2.40 


6.3 


1.9 


1.61 


1.68 


1.8 


.75 


.85 


.68 


4MX3XH-.. 


18.5 


5.43 


10.3 


3.6 


1.38 


1.65 


3.6 


1.7 


.81 


.90 


%... 


17.3 


5.06 


9.7 


3.4 


1.39 


1.63 


3.4 


1.6 


.82 


.88 


\\... 


16.0 


4.68 


9.1 


3.1 


1.39 


1.60 


3.2 


1.5 


.83 


.85 


%-■ 


14.7 


4.30 


8.4 


2.9 


1.40 


1.58 


3.0 


1.4 


.83 


.83 


ft-- 


13.3 


3.90 


7.8 


2.6 


1.41 


1.56 


2.8 


1.3 


.85 


.81 


H-- 


11.9 


3.50 


7.0 


2.4 


1.42 


1.54 


2.5 


1.1 


.85 


.79 


ft-- 


10.6 


3.09 


6.3 


2.1 


1.43 


1.51 


2.3 


1.0 


.85 


.76 


H-. 


9.1 


2.67 


5.5 


1.8 


1.44 


1.49 


2.0 


.88 


.86 


.74 


4X3HXil'^ 


7.7 


2.25 


4.7 


1.5 


1.44 


1.47 


1.7 


.75 


.87 


.72 


18.5 


5.43 


7.8 


2.9 


1.19 


1.36 


5.5 


2.3 


1.01 


1.11 


&... 


17.3 


5.06 


7.3 


2.8 


1.20 


1.34 


5.2 


2.1 


1.01 


1.09 


tt... 


16.0 


4.68 


6.9 


2.6 


1.21 


1.32 


4.9 


2.0 


1.02 


1.07 


H-. 


14.7 


4.30 


6.4 


2.4 


1.22 


1.29 


4.5 


1.8 


1.03 


1.04 


ft... 


13.3 


3.90 


5.9 


2.1 


1.23 


1.27 


4.2 


1.7 


1.03 


1.02 


H-.. 


11.9 


3.50 


5.3 


1.9 


1.23 


1.25 


3.8 


1.5 


1.04 


1.00 


fe:: 


10.6 


3.09 


4.8 


1.7 


1.24 


1.23 


3.4 


1.3 


1.05 


.98 


9.1 


2.67 


4.2 


1.5 


1.25 


1.21 


3.0 


1.2 


1.06 


.96 


ft... 


7.7 


2.25 


3.6 


1.3 


1.26 


1.18 


2.6 


1.0 


1.07 


.93 


4X3XH 


17.1 


5.03 


7.3 


2.9 


1.21 


1.44 


3.5 


1.7 


.83 


.94 


M 


16.0 


4.69 


6.9 


2.7 


1.22 


1.42 


3.3 


1.6 


.84 


.92 


H 


14.8 


4.34 


6.5 


2.5 


1.22 


1.39 


3.1 


1.5 


.84 


.89 


% 


13.6 


3.98 


6.0 


2.3 


1.23 


1.37 


2.9 


1.4 


.85 


.87 


ft 


12.4 


3.62 


5.6 


2.1 


1.24 


1.35 


2.7 


1.2 


.86 


.85 


M 


11.1 


3. 55 


5.0 


1.9 


1.25 


1.33 


2.4 


1.1 


.86 


.83 


ft 


9.8 


2.87 


4.5 


1.7 


1.2-i 


1.30 


2.2 


1.0 


.87 


.80 



134 



y Google 



Unequal Angles — Continued 





Weight 


Area of 




Axis 1-1 






Axis 2-2 






Foot 


Section 
Sq. Ins.. 


















Siae, IncheB 




















Pounds 


A 


/ 


S 


R 


X 


/ 


8 


R 


V 


4 X3 XH 


8.5 


2.48 


4.0 


1.5 : 


1.26 


1.28 


1.9 


.87 


.88 


.78 


ft::::: 


7.2 


2.09 


3.4 


1.2- 


1.27 


1.26 


1.7 


.74 


.89 


.76 


5.8 


1.69 


2.8 


1.0 


1.28 


1.24 


1.4 


.60 


.89 


.74 


3JiX3XH- 


15.8 


4.62 


5.0 


2.2. 


1.04 


1.23 


3.3 


1.7 


.85 


.98 


14.7 


4.31 


4.7 


2.1. 


1.04 


1.21 


3.1 


1.5 


.85 


.96 


■H*' 


13.6 


4.00 


4.4 


1.9 


1.05 


1.19 


3.0 


1.4 


.86 


.94 


H— 


12.5 


3.67 


4.1 


1.8 


1.06 


1.17 


2.8 


1.3 


.87 


.92 


1::: 


11.4 


3.34 


3.8 


1.6 


1.07 


1.15 


2.5 


1.2 


.87 


.90 


10.2 


3.00 


3.5 


1.5 


1.07 


1.13 


2.3 


1.1 


.88 


.88 


ft::: 


9.1 


2.65 


3.1 


1.3 


1.08 


1.10 


2.1 


.98 


.89 


.85 


7.9 


2.30 


2.7 


1.1 


1.09 


1.08 


1.8 


.85 


.90 


.83 


ft::: 


% 6.6 


1.93 


2.3 


.90 


1.16 


1.06 


1.6 


.72 


.90 


.81 


5.4 


1.56 


1.9 


.78 


1.11 


1.04 


1.3 


.58 


.91 


.79 


3K X 2H X «• 

78- 


12.5 
11.5 


3.65 
3.36 


4.1 
3.8 


1.9 
1.7 


1.06 
1.07 


1.27 
1.25 


1.7 
l.G 


.99 
.92 


.69 
.69 


.77 
.75 


ft: 


10.4 


3.06 


3.6 


1.6 


1.08 


1.23 


1.5 


.84 


.70 


.73 


9.4 


2.75 


3.2 


1.4 


1.09 


1.20 


1.4 


.76 


.70 


.70 


8: 


8.3 


2.43 


2.9 


1.3 


1.09 


1.18 


1.2 


.68 


.71 


.68 


7.2 


2.11 


2.6 


1.1 


1.10 


1.16 


1.1 


.59 


.72 


.66 


ft: 


6.1 


1.78 


2.2 


.93 


1.11 


1.14 


.94 


.50 


.73 


.64 


4.9 


1.44 


1.8 


.75 


1.12 


1.11 


.78 


.41 


.74 


.61 


3 X 2H Xft.-- 


9.5 


2.78 


2.3 


1.2 


.91 


1.02 


1.4 


.82 


.72 


.77 




8.5 


2.50 


2.1 


1.0 


.91 


1.00 


1.3 


.74 


.72 


.75 


A-- 


7.6 


2.21 


1.9 


.93 


.92 


.98 


1.2 


.66 


.73 


.73 


8... 


6.6 


1.92 


1.7 


.81 


.93 


.96 


1.0 


.58 


.74 


.71 


ft::: 


5.6 


1.62 


1.4 


.69 


.94 


.93 


.90 


.49 


.74 


.68 


4.5 


1.31 


1.2 


.56 


.95 


.91 


.74 


.40 


.75 


.66 


3 X 2 X H 


7.7 


2.25 


1.9 


1.0 


.92 


1.08 


.67 


.47 


.55 


.58 




'6.8 


2.20 


1.7 


.89 


.93 


1.06 


.61 


.42 


.55 


.56 


Si 


5.9 


1.73 


1.5 


.78 


.94 


1.04 


.54 


.37 


.56 


.54 


5.0 


1.47 


1.3 


.66 


.95 


1.02 


.47 


.32 


.57 


.52 


4.1 


1.19 


1.1 


.54 


.95 


.99 


.39 


.25 


.57 


.49 


2J4X2XH... 

ft::: 


6.8 


2.00 


1.1 


.70 


.75 


.88 


.64 


.46 


.56 


.63 


6.1 


1.78 


1.0 


.62 


.76 


.85 


.58 


.41 


.57 


.60 


5.3 


1.55 


.91 


.55 


.77 


.83 


.51 


.36 


.58 


.58 


I: 

2HX1HXA- 


4.5 


1.31 


.79 


.47 


.78 


.81 


.45 


.31 


.58 


.56 


3.62 


1.06 


.65 


.38 


.78 


.79 


.37 


.25 


.59 


.54 


2.75 


.81 


.51 


.29 


.79 


.76 


.29 


.20 


.60 


.51 


1.86 


.55 


.35 


.20 


.80 


.74 


.20 


.13 


.61 


.49 


3.92 
3.19 


1.15 
.94 


.71 
.59 


.44 
.36 


.79 
.79 


.90 
.88 


.19 
.16 


.17 
.14 


.41 

.41 


.40 
.38 


A- 


2.44 


.78 


.46 


.28 


.80 


.85 


.13 


.11 


.42 


.35 


2M X im X H. 


5.6 
5.0 


1.03 
1.45 


.75 
.68 


.54 

.48 


.68 
.69 


.86 
.83 


.26 
.24 


.26 
.23 


.40 
.41 


.48 
.46 


4.4 


1.27 


.61 


.42 


.69 


.81 


.21 


.20 


.41 


.44 


I 

JXWXH... 

1: 

2XMXH'- 
IK X IK X K. 


3.66 


1.07 


.53 


.36 


.70 


.79 


.19 


.17 


.42 


.42 


2.98 


.88 


.44 


.30 


.71 


.77 


.16 


.14 


.42 


.39 


2.28 


.67 


.34 


.23 


.72 


.75 


.12 


.11 


.43 


.37 


3.99 
3.39 


1.17 
1.00 


.43 
.38 


.34 

.29 


.61 
.62 


.71 
.69 


.21 
.18 


.20 
.17 


.42 
.42 


.46 
.44 


2.77 


.81 


.32 


.24 


.62 


.66 


.15 


.14 


.43 


.41 


2.12 


.62 


.25 


.18 


.63 


.64 


.12 


.11 


.44 


.39 


1.44 


.42 


.17 


.13 


.64 


.62 


.09 


.08 


.45 


.37 


2.55 
1.96 


.75 
.57 


.30 
.23 


.23 
.18 


.63 
.64 


.71 
.69 


.09 
.07 


.10 

.08 


.34 
.35 


.33 
.31 


2.34 
1.80 


.69 
.53 


.20 
.16 


.18 
.14 


' .54 
.55 


.60 

.58-- 


.09 
.07 


.10 
.08 


.35 
.36 


.35 
.33 


1.23 


.36 


.11 


.09 


.56 


.56 


.05 


.05 


.37 


.31 


W2XVAX A. 
A^ 


2.59 
2.13 


.76 
.63 


.16 
.13 


.16 
.13 


.45 

.46 


.52 
.50 


.10 
.08 


.11 
.09 


.35 
.36 


.40 
.38 


1.64 


.48 


.10 


.10 


.46 


.48 


.07 


.07 


r* 7 


.35 



135 



uiflitizsa by V-jvJ<J^L ' C 



I Beams 




Depth 

Of 
Beam 


Weight 


Ana 

of 

Section 


Width 
of 

J Vuv 


Thiek- 


Aria 1-1 


A™ 2-2 


per 
loot 


of 
Web 


/ 


S 


R 


/ 


S 


fi 


27 


83. 


24.41 


7.5 


.424 


2888.6 


214. 


10.88 


53.1 


14.1 


1.47 




115.0 


33.98 


8. 


.750 


2955.5 


246.3 


9.33 


83.2 


20.8 


1.57 


24 


110.0 


32.48 


7.938 


.688 


2883.5 


240.3 


9.42 


81. 


20.4 


1.58 




105. 


30.98 


7.875 


.625 


2811.5 


234.3 


9.53 


78.9 


20. 


1.60 




100. 


29.41 


7.254 


.754 


2379.6 


198.3 


9.00 


48.6 


13.4 


1.28 




95. 


27.94 


7.193 


.693 


2309. 


192.4 


9.09 


47.1 


13.1 


1.30 




90. 


26.47 


7.131 


.631 


2238.4 


186.5 


9.20 


45.7 


12.8 


1.31 




85. 


25.00 


7.070 


.570 


2167.8 


180.7 


9.31 


44.4 


12.6 


1.33 




80. 


23.32 


7. 


.5 


2087.2 


173.9 


9.46 


42.9 


12.3 


1.36 




69.5 


20.44 


7. 


.39 


1928. 


160.7 


9.71 


39.3 


11.2 


1.39 


21 


57.5 


16.85 


6.5 


.357 


1227.5 


116.9 


9.54 


28.4 


8.8 


1.30 


20 


100. 


29.41 


7.284 


.884 


1655.6 


165.6 


7.50 


52.7 


14.5 


1.34 




95. 


27.94 


7.210 


.810 


1606.6 


160.7 


7.58 


50.* 


14.1 


1.35 




90. 


26.47 


7.137 


.737 


1557.6 


155.8 


7.67 


49. 


13.7 


1.36 




85. 


25.00 


7.063 


.663 


1508.5 


150.9 


7.77 


47.3 


13.4 


1.37 




80. 


23.53 


7. 


.6 


1466.3 


146.6 


7.86 


45.8 


13.1 


1.39 




75. 


22.05 


6.399 


.649 


1268.8 


126.9 


7.58 


30.3 


9.5 


1.17 




70. 


20.59 


6.325 


.575 


1219.8 


122. 


7.70 


29. 


9.2 


1.19 




65. 


19.12 


6.25 


.5 


1169.5 


117. 


7.83 


27.9 


8.9 


1.21 


18 


90. 


17.65 


7.245 


.807 


1260.4 


140. 


6.90 


52. 


14.4 


1.40 




85. 


15.93 


7.163 


.725 


1220.7 


135.6 


6.99 


50. 


14.0 


1.42 




80. 


13.53 


7.082 


.644 


1181. 


131.2 


7.09 


48.1 


13.6 


1.43 




75. 


22.06 


7. 


.562 


1141.3 


126.8 


7.19 


46.2 


13.2 


1.45 




70. 


20.59 


6.259 


.719 


921.2 


102.4 


6.69 


24.6 


7.9 


1.09 




65. 


19.12 


6.177 


.637 


881.5 


97.9 


6.79 


23.5 


7.6 


1.11 




60. 


17.67 


6.095 


.555 


841.8 


93.5 


6.91 


22.4 


7.3 


1.13 




55. 


15.93 


6. 


.46 


795.6 


88.4 


7.07 


21.2 


7.1 


1.15 




46. 


13.53 


6. 


.322 


733.2 


81.5 


7.36 


19.9 


6.6 


1.21 


15 


75. 


22.06 


6.292 


.882 


691.2 


92.2 


5.60 


30.7 


9.8 


1.18 




70. 


20.59 


6.194 


.784 


663.7 


88.5 


5.68 


29. 


9.4 


1.19 




65. 


19.12 


6.096 


.686 


636.1 


84.8 


5.77 


27.4 


9. 


1.20 




60. 


17.67 


6. 


.59 


609. 


81.2 


5.87 


26. 


8.7 


1.21 




55. 


16.18 


5.746 


.656 


511. 


68.1 


5.62 


17.1 


5.9 


1.02 




50. 


14 71 


5.648 


.558 


483.4 


64.5 


5.73 


16. 


5.7 


1.04 




45. 


13.24 


5.550 


.46 


455.9 


60.8 


5.87 


15.1 


5.4 


1.07 




42. 


12.48 


5.5 


.41 


441.8 


58.9 


5.95 


14.6 


5.3 


1.08 




36. 


10.63 


5.5 


.289 


405.1 


54. 


6.17 


13.5 


4.9 


1.13 


12 


55. 


16.18 


5.611 


.821 


321. 


53 5 


4.45 


17.5 


6.2 


1.04 




50. 


14.71 


5.489 


.699 


303.4 


50.6 


5.54 


16.1 


5.9 


1.05 



136 



y Google 



I Beams — Continued 



Depth 


Weight 


Area 


Width 


Thick- 


Axifll— 1 






Axis 2— 2 


of 
Beam 


Foot 


of 
Section 


of 
Flange 


ness 

of 

Web 














/ 


i 
S 


R 


/ 


8 


B 


12 


45. 


13.24 


5.366 


.576 


285.7 


47.6 


4.65 


14.9 


5.6 


1.06 




40. 


11.84 


5.25 


.460 


269. 


44.8 


4.77 


13.8 


5.3 


1.08 




35. 


10.29 


5.086 


.436 


228.3 


38. 


4.71 


10.1 


4. 


1.09 




31.5 


9.26 


5. 


.35 


215.8 


36. 


4.83 


9.5 


3.8 


1.01 




27.5 


8.04 


5. 


.255 


199.6 


33.3 


4.98 


8.7 


3.5 


1.04 


10 


40. 


11.76 


5.099 


.749 


158.7 


31.7 


3.67 


9.5 


3.7 


.90 




35. 


10.29 


4.952 


.602 


146.4 


29.3 


3.77 


8.5 


3.4 


.91 




30. 


8.82 


4.805 


.455 


134.2 


26.8 


3.90 


7.7 


3.2 


.93 




25. 


7.37 


4.66 


.310 


122.1 


24.4 


4.07 


6.9 


3. 


.97 




22. 


6.52 


4.67 


.232 


113.9 


22.8 


4.18 


6.4 


2.7 


.99 


9 


35. 


10.29 


4.772 


.732 


111.8 


24.8 


3.29 


7.3 


3.1 


.84 




30. 


8.82 


4.609 


.569 


101.9 


22.6 


3.40 


6 4 


2.8 


.85 




25. 


7.35 


4.446 


.406 


91.9 


20.4 


3.54 


5.7 


2.5 


.88 




21. 


6.31 


4.33 


.29 


84.9 


18.9 


3.67 


5.2 


2.4 


.90 


8 


25.5 


7.50 


4.271 


.541 


68.4 


17.1 


3.02 


4.8 


2.2 


.80 




23. 


6.76 


4.179 


.449 


64.5 


16.1 


3.09 


4.4 


2.1 


.81 




20.5 


6.03 


4.087 


.357 


60.6 


15.2 


3.17 


4.1 


2. 


.82 




18. 


6.33 


4. 


.27 


56.9 


14.2 


3.27 


3.8 


1.9 


.84 




17.5 


5.15 


4.33 


.21 


58.3 


14.6 


3.37 


4.5 


2.1 


.93 


7 


20. 


5.88 


3.868 


.458 


42.2 


12.1 


2.68 


3.2 


1.7 


.74 




17.5 


5.15 


3.763 


.353 


39.2 


11.2 


2.76 


2.9 


1.6 


.76 




15. 


4.42 


3.66 


.25 


36.2 


10.4 


2.86 


2.7 


1.6 


.78 


6 


17.25 


5.07 


3.575 


.475 


26.2 


8.7 


2.27 


2.4 


1.3 


.68 




14.75 


4.34 


3.452 


.352 


24. 


8. 


2.35 


2.1 


1.2 


.69 




12.25 


3.61 


3.33 


.23 


21.8 


7.3 


2.46 


1.9 


1.1 


.72 


5 


14.75 


4.34 


3.294 


.504 


15.2 


6.1 


1.87 


1.7 


1. 


.63 




12.25 


3.6 


3.147 


.357 


13.6 


5.5 


1.94 


1.5 


.92 


.63 




9.75 


2.87 


3. 


.21 


12.1 


4.8 


2.05 


1.2 


.82 


.65 


4 


10.5 


3.09 


2.88 


.41 


7.1 


3.6 


1.52 


1. 


.7 


.57 




9.5 


2.79 


2.807 


.337 


6.8 


3.4 


1.55 


.93 


.66 


.58 




8.5 


2.5 


2.733 


.263 


6.4 


3.2 


1.59 


.85 


.62 


.58 




7.6 


2.21 


2.66 


.190 


6. 


3. 


1.64 


.77 


.68 


.59 


3 


7.5 


2.21 


2.521 


.361 


2.9 


1.9 


1.15 


.60 


.48 


.52 




6.5 


1.91 


2.423 


.263 


2.7 


1.8 


1.19 


.53 


.44 


.52 




5.5 


1.63 


2.33 


.170 


2.5 


1.7 


1.23 


.46 


.40 


.53 



Half Rounds 



Diameter A" to J£*\ inclusive, advancing by 64ths. 
ft" " 1%', a * 16ths. 

2", 2W, 3", 



Rounds 



Diameter - 



tA' to \ % /i' y inclusive, advancing by 64ths. 
Iff' u W, * tt * 32nds. 

a 3A' a 7", «" u 16ths. 

See also page 143 



137 



Digiti 



zed by G00gk 



Bulb Beams 



12 



f 



j% 



Depth 


Weight 


Area 


Width 


Thick- 




Axis 


1—1 






Axis 2— 2 


• 


of 
Beam 


per 
Foot 


of 
Section 


of 
Flange 


of 
Web 


















/ 


A 


R 


X 


/ 


S 


R 


V 


10 


36.6 


10.62 


5.500 


.625 


140.4 


25.3 


3.64 


4.45 


7.6 


2.8 


.84 


2.75 




28.1 


8.12 


5.250 


.375 


118.6 


20.7 


3.82 


4.28 


6.3 


2.4 


.88 


2.63 


9 


30.1 


8.83 


5.125 


.563 


95.8 


19.4 


3.29 


4.06 


5.4 


2.1 


.78 


2.56 




24.3 


7.15 


4.938 


.375 


84.0 


16.6 


3.43 


3.95 


4.6 


1.9 


.80 


2.47 


8 


24.2 


7.11 


5.156 


.469 


62.8 


14.1 


2.97 


3.54 


4.5 


1.7 


.79 


2.58 




20.0 


5.86 


5.000 


.313 


55.6 


12.2 


3.08 


3.43 


3.9 


1.6 


.82 


2.50 


7 


23.3 


6.85 


5.094 


.531 


45.5 


11.7 


2.57 


3.11 


4.3 


1.7 


.79 


2.55 




18.1 


5.32 


4.875 


.313 


38.8 


9.7 


2.70 


2.98 


3.6 


1.5 


.82 


2.44 


6 


17.2 


5.00 


4.524 


.430 


24.4 


7.2 


2.20 


2.61 


2.7 


1.2 


.73 


2.26 




14.0 


4.11 


4.375 


.281 


21.6 


6.1 


2.28 


2.46 


2.2 


1.0 


.72 


2.19 



H Beams 




Depth 
of 


Weight 


Area 
of 


Width 
of 


Thick- 
ness 


Axis 1 — 1 


Axis 2— 2 


per 


of 
Web 










Beam 


Foot 


Section 


Flange 


/ 


S 


R 


/ 


S 


R 


8 


34. 


10. 


8. 


.375 


115.4 


28.9 


3.40 


35.1 


8.8 


1.87 


6 


23.8 


7. 


6. 


.313 


45.1 


15. 


2 54 


14.7 


4.9 


1.45 


5 


18.7 


5.50 


5. 


.313 


23.8 


9.5 


2.08 


7.9 


3.1 


1.20 


4 


13.6 


4. 


4. 


.313 


10.7 


5.3 


1.63 


3.6 


1.8 


.95 



138 



y Google 



Bulb Angles 



if 



■*? 



/ 

T 
X 



Depth 
of 


Weight 


Area 
of 


Width 
of 


Thick- 
ness 


Axis 1—1 


Axis 2— 2 


per 


of 
Web 


















Angle 


Foot 


Section 


Flange 


/ 


S 


B 


X 


/ 


S 


R 


V 


10 


32.0 


9.41 


3.500 


.625 


116.0 


21.6 


3.51 


4.62 


6.2 


2.3 


.82 


.77 




2b. 6 


7.80 




.484 


104.2 


19.9 


3.66 


4.75 


5.0 


18 


.80 


.72 


9 


21.8 


6.41 




.438 


69.3 


14.5 


3.33 


4.21 


4.3 


1.5 


.82 


.72 


8 


19.3 


5.66 




.406 


48 8 


11.7 


2.95 


3.83 


3.7 


1.3 


.81 


.71 


7 


20.0 


5.81 


3.000 


.500 


36.6 


10.0 


2.51 


3.34 


2.9 


1.3 


.71 


.70 




18.3 


5.37 




.438 


34.9 


9.6 


2.56 


3.36 


2.6 


1.1 


.69 


.68 




16.1 


4.71 




.b44 


32.2 


8.7 


2.61 


3.30 


2.7 


1.2 


.76 


.72 


6 


17.3 


5.06 




.500 


23.9 


7.6 


2.16 


2.84 


2.5 


1.1 


.70 


.71 




15.0 


4.38 




.406 


21.1 


6.7 


2.19 


2.84 


2.3 


1.0 


.72 


.69 




13.8 


4.04 




.375 


20.1 


6.6 


2.21 


2.96 


1.9 


.82 


.69 


.65 




12.4 


3.62 




.313 


18.6 


5.7 


2.28 


2.71 


1.8 


.75 


.70 


.64 


5 


13.2 


3.82 


3.500 


.375 


13.5 


4.9 


1.88 


2.22 


3.3 


1.24 


.92 


.86 




10.0 


2.94 


2.500 


.313 


10.2 


4.1 


1.86 


2.49 


.95 


.49 


.57 


.57 




8.3 


2.44 




.240 


8.6 


3.4 


1.89 


2.41 


.91 


.47 


.61 


.55 


4V?, 


6.7 


1.95 


2.250 


.220 


5.6 


2.4 


1.69 


2.12 


.60 


.34 


.56 


.50 


4 


14.3 


4.21 


3.500 


.500 


8.7 


3.7 


1 44 


1.65 


3.9 


1.5 


.96 


.99 




11.9 


3.48 




.375 


7.9 


3.5 


1.50 


1.77 


3.1 


1.2 


.94 


.94 


3 


3.60 


1.08 


2.000 


.190 


1.3 


.74 


1.09 


1.24 


.31 


.20 


.54 


.45 




3.25 


.97 


1.750 


.160 


1.2 


.72 


1.13 


1.31 


.21 


.16 


.47 


.41 


2H 


2.66 


.84 


1.500 


.150 


.74 


.55 


.94 


1.17 


.12 


.11 


.38 


.36 



Band Edge Flats 



%' 




wide 


X No 


. 18 


A' 




« 


X 


19 


V*' 




u 


X 


22 


A' to 


i', 


u 


X 


23 


1A' " 


2', 


u 


X 


22 


2A' « 


3', 


u 


X 


21 


3A' « 


3H', 


u 


X 


20 


3A* « 


4', 


it 


X 


19 


4A' « 


4^', 


u 


X 


18 


4A' « 


5A', 


a 


X 


17 


VA" " 


6W, 


u 


X 


16 


»tt' « 


m: 


u 


X 


14 


sh' • 


9%", 


u 


X 


12 



m « 



139 



Digiti 



zed by G00gk 



7 






Sin 






























Weight 
Foot 


Area 
of 

Sec- 




Axis 1-1 




Axis 2-2 








Minimum 

Thickness 




















Flange 


Stem 






tion 


/ 


8 


B 


X 


/ 


8 










R 






Flange 


Stem 




















4 


4 


M 


8 


13.5 


3.97 


5.7 


2. 


1.20 


1.18 


2.8 


1.4 


.84 






H 


10.5 


3.09 


4.5 


1.6 


1.21 


1.13 


2.1 


1.1 


.83 


3H 


M 


H 


^ 


11.7 


3.44 


3.7 


1.5 


1.04 


1.05 


1.9 


1.1 


.74 






% 


-a 


9.2 


2.68 


3.0 


1.2 


1.05 


1.01 


1.4 


.81 


.73 


3 


3 


H 


9.9 


2.91 


2.3 


1.1 


.88 


.93 


1.2 


.80 


.64 






6 


« 


8.9 


2.59 


2.1 


.98 


.89 


.91 


1.0 


.70 


.63 






7.8 


2.27 


1.8 


.86 


.90 


.88 


.90 


.60 


.63 






£ 


ft 


6.7 


1.95 


1.6 


.74 


.90 


.86 


.75 


.50 


.62 


2H 


2H 


6.4 


1.87 


1.0 


.59 


.74 


.76 


.52 


.42 


.53 








A 


5.5 


1.60 


.88 


.5 


.74 


.74 


.44 


.35 


.52 


2H 


2H 


A 


ft 


•4.9 


1.43 


.65 


.41 


.67 


.68 


.33 


.29 


.48 






Vi 


4.1 


1.19 


.52 


.32 


.66 


.65 


.25 


.22 


.46 


2 


2 


A 




4.3 


1.26 


.44 


.31 


.59 


.61 


.23 


.23 


.43 






yi 


y^ 


3.56 


1.05 


.37 


.26 


.59 


.59 


.18 


.18 


.42 


IH 


IH 


\i 


H 


3.09 


.91 


.23 


.19 


.51 


.54 


.12 


.14 


.37 


V4 


m 


i^ 


X 


2.47 


.73 


.15 


.14 


.45 


.47 


.08 


.10 


.32 






| 


ft 


1.94 


.67 


.11 


.11 


.45 


.44 


.06 


.08 


.32 


IH 


1M 


2.02 


.69 


.08 


.10 


.37 


.40 


.05 


.07 


.28 








A 


1.59 


.47 


.06 


.07 


.37 


.38 


.03 


.05 


.27 


1 


1 


A, 


A 


1.25 


.37 


.03 


.05 


.29 


.32 


.02 


.04 


.22 






K 


H 


.89 


.26 


.02 


.03 


.30 


.29 


.01 


.02 


.21 



Over 



3' 


u 


5' 


5* 


u 


V 


V 


u 


7H* 


7W 


u 


8' 



Square Edge Flats 
%" to 3" wide X any thickness, y% up to width. 

X u u K" to 3', inclusive. 

X " " H" tt 2", « 

X a u A' u M, " 

X u " A' u 1", u 

Squares 
Size A" to 2", inclusive, advancing by 64ths. 
tt 2A' u *Wi u u tt 32nds. 

u 3 A' " W, " u a 16ths. 

Round Cornered Squares 
Size Ji* to Ji", inclusive, advancing by 



140 



64ths. 



Unequal Tehs 
12 



2F 



III 





Size 




























Weight 
Foot 


Area 
of 
Sec- 




Axis 1-1 




A 


ois 2-2 






Minimum 
Thickness 




















Flange 


Stem 






tion 


/ 


8 


R 


X 


/ 


S 












R 






Flange 


Stem 




















5 


3 


H 


11 


13.4 


3.. -3 


2.4 


1.1 


.78 


.73 


5.4 


2.2 


1.17 




2H 


N 


A 


10.9 


3.18 


1.5 


.78 


.68 


.63 


4.1 


1.6 


1.14 


4H 


m 


A 


H 


15.7 


4.60 


5.1 


2.1 


1.05 


1.11 


3.7 


1.7 


.90 




3 


N 


% 


9.8 


2.88 


2.1 


.91 


.84 


.74 


3. 


1.3 


1.02 




3 


ft 


ft 


8.4 


2.46 


1.8 


.78 


.85 


.71 


2.5 


1.1 


1.01 




2H 


9.2 


2.68 


1.2 


.63 


.67 


.59 


3. 


1.3 


1.05 




2H 


ft 


A 


7.8 


2.29 


1. 


.54 


.68 


.57 


2 5 


1.1 


1.05 


4 


5 


8 


15.3 


4.50 


10.8 


3.1 


1.55 


1.56 


2.8 


1.4 


.79 




5 


8 


11.9 


3.49 


8.5 


2.4 


1.56 


1.51 


2.1 


1.1 


.78 




4H 


II 


14.4 


4.23 


7.9 


2.5 


1.37 


1.37 


2.8 


1.4 


.81 




4K 


H 


11.2 


3.29 


6.3 


2. 


1.39 


1,31 


2.1 


1.1 


.80 




3 


H 


H 


9.2 


2.68 


2. 


.9 


.86 


.78 


2.1 


1.1 


.89 




3 


ft 


ft 


7.8 


2.29 


1.7 


.77 


.87 


.75 


1.8 


.88 


.88 




2H 


8.5 


2.48 


1.2 


.62 


.69 


.62 


2.1 


1. 


.92 




2H 


ft 


ft 


7.2 


2.12 


1. 


.53 


.69 


.6 


1.8 


.88 


.91 




2 


7.8 


2.27 


.60 


.40 


.52 


.48 


2.1 


1.1 


96 




2 


ft 


ft 


6.7 


1.95 


.53 


.34 


.52 


.46 


1.8 


.88 


.95 


2K 


4 


12.6 


3.70 


5.50 


2. 


1.21 


1.24 


1.9 


1.1 


.72 




4 


K 


H 


9.8 


2.88 


4.30 


1.5 


1.23 


1.19 


1.4 


.81 


.70 




3 


H 


H 


10.8 


3.17 


2.4 


1.1 


.87 


.88 


1.9 


1.1 


.77 




3 


*A 


M 


8.5 


2.48 


1.9 


.89 


.88 


.83 


1.4 


.81 


.75 




3 


ft 


H 


7.5 


2.20 


1.8 


.85 


.91 


.85 


1.2 


.68 


.74 


3 


4 


X 


11.7 


3.44 


5 2 


1.9 


1.23 


1.32 


1.2 


.81 


.59 




4 


ft 


ft 


10.5 


3.06 


4.7 


1.7 


1.23 


1.29 


1.1 


.7 


.59 




4 


9.2 


2.68 


4.1 


1.5 


1.24 


1.27 


.9 


.6 


.58 




M 


M 


X 


10.8 


3.17 


3.5 


1.5 


1.06 


1.12 


1.2 


.8 


.62 




3H 


ft 


ft 


9.7 


2.83 


3.2 


1.3 


1.06 


1.1 


1. 


.69 


.60 




3H 


8.5 


2.48 


2.8 


1.2 


1.07 


1.07 


.93 


.62 


.61 




2H 


H 


H 


7.1 


2.07 


1.1 


.6 


.72 


.71 


.89 


.59 


.66 




2H 


ft 


ft 


6.1 


1.77 


.94 


.52 


.73 


.68 


.75 


.50 


.65 


2H 


3 


7.1 


2.07 


1.7 


.84 


.91 


.95 


.53 


.42 


.51 




3 


A 


A 


6.1 


1.77 


1.5 


.72 


.92 


.92 


.44 


.35 


.50 




IH 


ft 


ft 


2.87 


.84 


.08 


.09 


.31 


.32 


.29 


.23 


.58 


2 


3.09 


.91 


.16 


.15 


.42 


.42 


.18 


.18 


.45 


1J4 


2 


ft 


ft 


2.45 


.72 


.27 


.19 


.61 


.63 


.06 


.08 


.92 




IK 


1.25 


.37 


.05 


.05 


.37 


.33 


.04 


.05 


.32 


IK 


^ 


H 


H 


.88. 


.26 


.01 


.01 


.16 


.16 


.02 


.04 


.31 



Keys. — For square and flat steel keys, let d = diameter of shaft, 
w = width of key, t = thickness, all in inches. Then w = -r + A", 
t = o + 14", common taper }4" = V, length 1.5<J. 

141 



8 



Zees 




Siae 


Weight 


Area 

of Sec- 
tion 


Axis 1-1 


Axis 2-2 


Depth 


Flanges 


Thickness 


Foot 


/ 


s 


R 


/ 


S 


R 


m 


3^ 


H 


34.6 


10.17 


50.2 


16.4 


2.22 


19.2 


6.0 


1.37 


6A 


3A 


tt 


32.0 


9.40 


46.1 


15.2 


2.22 


17.3 


5.5 


1.36 


6 


3»^ 


% 


29.4 


8.63 


42.1 


14.0 


2.21 


15.4 


4.9 


1.34 


6H 


3^ 


8 


28.1 


8.25 


43.2 


14.1 


2.29 


16.3 


5.0 


1.41 


6^ 


3A 


25.4 


7.46 


38.9 


12.8 


2.28 


14.4 


4.4 


1.39 


6 


3^ 


A 


22.8 


6.68 


34.6 


11.5 


2.28 


12.6 


3.9 


1.37 


6H 


3^ 


H 


21.1 


6.19 


34.4 


11.2 


2.36 


12.9 


3.8 


1.44 


6* 


3A 




18.4 


5.39 


29.8 


9.8 


2.35 


11.0 


3.3 


1.43 


6 


3^ 


% 


15.7 


4.59 


25.3 


8.4 


2.35 


9.1 


2.8 


1.41 


5H 


SH 


H 


28.4 


8.33 


28.7 


11.2 


1.86 


14.4 


4.8 


1.31 


5A 


3ft 


/4 


26.0 


7.64 


26.2 


10.3 


1.85 


12.8 


4.4 


1.30 


5 


3M 


■$ 


23.7 


6.96 


23.7 


9.5 


1.84 


11.4 


3.9 


1.28 


w% 


3H 


H 


22.6 


6.64 


24.5 


9.6 


1.92 


12.1 


3.9 


1.35 


5A 


3ft 


A 


20.2 


5.94 


21.8 


8.6 


1.91 


10.5 


3.5 


1.33 


5 


VA 


H 


17.9 


5.25 


19.2 


7.7 


1.91 


9.1 


3.0 


1.31 


5H 


3H 


A 


16.4 


4.81 


19.1 


7.4 


1.99 


9.2 


2.9 


1.38 


5tV 


3ft 


H 


14.0 


4.10 


16.2 


6.4 


1.99 


7.7 


2.5 


1.37 


5 


3^ 




11.6 


3.40 


13.4 


5.3 


1.98 


6.2 


2.0 


1.35 


*H 


3ft 


23.0 


5.75 


15.0 


7.3 


1.49 


11.2 


4.0 


1.29 


4A 


20.9 


6.14 


13.5 


6.7 


1.48 


10.0 


3.6 


1.27 




3ft 


H 


18.9 


5.55 


12.1 


6.1 


1.48 


8.7 


3.2 


1.25 


4H 


3ft 


& 


18.0 


5.27 


12.7 


6.2 


1.55 


9.3 


3.2 


1.33 


4A 


3H 


15.9 


4.66 


11.2 


5.5 


1.55 


8.0 


2.8 


1.31 




3ft 


ft 


13.8 


4.05 


9.7 


4.8 


1.55 


6.7 


2.4 


1.29 


4^ 


3ft 


12.5 


3.66 


9.6 


4.7 


1.62 


6.8 


2.3 


1.36 


4A 


m 


ft 


10.3 


3.03 


7.9 


3.9 


1.62 


5.5 


1.8 


1.34 


4 * 


3ft 


8.2 


2.41 


6.3 


3.1 


1.62 


4.2 


1.4 


1.33 


3A 


3 


ft 


14.3 


4.18 


5.3 


3.4 


1.12 


5.7 


2.3 


1.17 


3 


12.6 


3.69 


4.6 


3.1 


1.12 


4.9 


2.0 


1.15 


3* 


234 


ft 


11.5 


3.36 


4.6 


3.0 


1.17 


4.8 


1.9 


1.19 


3 


2tt 


9.8 


2.86 


3.9 


2.6 


1.16 


3.9 


1.6 


1.17 


3* 


2H 


ft 


8.5 


2.48 


3.6 


2.4 


1.21 


3.6 


1.4 


1 21 


3 


2H 


6.7 


1.97 


2.9 


1.9 


1.21 


2.8 


1.1 


1.19 



Hexagons. 

Size from flat to flat \i" to If!" inclusive, advancing by 32nds. 

a a a a a ^ « 3^ « « a 16thg 

a a « a « 3 A* 



142 



Digiti 



zed by G00gk 



Weights and Areas of Square and Round Bars and Circum- 
ferences of Round Bars 
One cubic foot of steel weighs 489.6 lb. 



Thickness 

or 
Diameter 
in Inches 


Weight of 
■ Bar 

One Foot 
Lome 


Weight of 
• Bar 

One Foot 
Long 


Area of 

■ Bar 

in Square 

Inches 


Area of 

• Bar 

in Sauare 

Inches 


Circumfer- 
ence of 
• Bar 
in Inches 


A 

* 

A 


.013 
.021 

.030 
.041 


.010 
.016 

.023 
.032 


.0039 
.0061 
.0088 
.0120 


.0031 
.0048 
.0069 
.0094 


.1964 
.2454 
.2945 
.3436 


1 

ft 


.053 
.067 
.083 
.100 


.042 
.053 
.065 
.079 


.0156 
.0198 
.0244 
.0295 


.0123 
.0155 
.0192 
.0232 


.3927 
.4418 
.4909 
.5400 


A 
ft 
A 
ft 


.120 
.140 
.163 
.187 


.094 
.110 
.128 
.147 


.0352 
.0413 
.0479 
.0549 


.0276 
.02124 
.0376 
.0431 


.5891 
.6381 . 
.6872 
.7363 


1 

ft 
A 
ft 


.212 
.240 
.269 

.300 

• 


.167 
.188 
.211 
.235 


.0625 
.0706 
.0791 
.0881 


.0491 
.0554 
.0621 
.0692 


.7854 
.8345 
.8836 
.9327 


A 

ft 
ft 
ft 


.332 
.366 
.402 
.439 


.261 
.288 
.316 
.345 


.0977 
.1077 
.1182 
.1292 


.0767 
.0846 
.0928 
.1014 


.9818 
1.0308 
1.0799 
1.1290 


f 

ft 
H 
ft 


- .478 
.519 
.561 
.605 


.376 
.407 
.441 
.475 


.1406 
.1526 
.1650 
.1780 


.1104 
.1198 
.1296 
.1398 


1.1781 
1.2272 
1.2763 
1.3254 


A 
ft 
ft 
ft 


.651 
.698 
.747 
.798 


.511 

.548 
.587 
.627 


.1914 
.2053 
.2197 
.2346 


.1503 
.1613 
.1726 
.1843 


1.3745 
1.4235 
1.4726 
1.5217 


A 

H 


.850 

.904 

.960 

1.017 


.668 
.710 
.754 
.799 


.2500 
.2659 

.2822 
.2991 


.1963 
.2088 
.2217 
.2349 


1.5708 
1.6199 
1.6690 
1.7181 


A 

II 

ft 


1.076 
1.136 
1.199 
1.263 


.845 
.893 
.941 
.992 


.3164 
.3342 
.3525 
.3713 


.2485 
.2625 
.2769 
.2916 


1.7672 
1.8162 
1.S653 
1.9144 


I 

1 


1.328 
1.395 
1.464 
1.535 


1.043 
1.096 
1.150 
1.205 


.3906 
.4104 
.4307 
.4514 


.3068 
.3223 
.3382 
.3545 


1.9635 
2.0126 
1.0617 
2.1108 



143 



Square and Round Bars — Continued 



Thickness 

or 
Diameter 
in Inches 


Weight of 
■ Bar 

One Foot 
Long 


Weight of 
• Bar 

One Foot 
Long 


Area of 

■ Bar 

in Square 

Inches 


Area of 

#Bar 

in Sauare 

Inches 


Circumfer- 
ence of 
• Bar 
in Inches 


1 


1.607 
1.681 
1.756 
1.834 


1.262 
1.320 
1.380 
1.440 


.4727 
.4944 
.5166 
.5393 


.3712 
.3883 
.4057 
.4236 


2.1599 
2.2089 
2.2580 
2.3071 


i 


1.913 
2.245 
2.603 
2.988 


1.502 
1.763 
2.044 
2.347 


.5625 
.6602 
.7656 
.8789 


.4418 
.5185 
.6013 
.6903 


2.3562 
2.5526 
2.7489 
2.9453 


1 

A 


3.400 
3.838 
4.303 
4.795 


2.670 
3.015 
3.380 
3.766 


1.0000 
1.1289 
1.2656 
1.4102 


.7854 

.8866 

,9940 

1.1075 


3.1416 
3.3380 
3.5343 
3.7306 


A 
A 


5.3J3 
5.857 
6.428 
7.026 


4.172 
4.600 
5.049 
5.518 


1.5625 
1.7227 
1.8906 
2.0664 


1.2272 
1.3530 
1.4849 
1.6230 


3.9270 
4.1234 
4.3197 
4.5161 


A 

1 

ii 


7.650 
8.301 
8.978 
9.682 


6.008 
6.519 
7.051 
7.604 


2.2500 
2.4414 
2.6406 
2.8477 


1.7671. 
1.9175 
2.0739 
2.2365 


4.7124 
4.9088 
5.1051 
5.3015 


4 
4 


10.41 
11.17 
11.95 
12.76 


8.178 
8.773 
9.388 
10.02 


3.0625 
3.2852 
3.5156 
3.7539 


2.4053 
2.5802 
2.7612 
2.9483 


5.4978 

. 5.6942 

5.8905 

6.0869 


2 

A 


13.60 
14.46 
15.35 
16.27 


10.68 
11.36 
12.06 
12.78 


4.0000 
4.2539 
4.5156 

4.7852 


3.1416 
3.3410 
3.5466 

3.7583 


6.2832 
6.4796 
6.6759 
6.8723 


A 

I 


17.21 
18.18 
19.18 
20.20 


13.52 
14.28 
15.06 
15.87 


5.0625 
5.3477 
5.6406 
5.9414 


3.9761 
4.2000 
4.4301 
4.6664 


7.0686 
7.2650 
7.4613 
7.6577 


i 

A 
i 

ii 


21.25 
22.33 
23.43 
24.56 


16.69 
17.53 
18.40 
19.29 


6.2500 
6.5664 
6.8906 
7.2227 


4.9087 
5.1573 
5.4119 
5.6727 


7.8540 
8.0504 
8.2467 
8.4431 


i 

i 


25.71 

26.90 
28.10 
29.34 


20.19 
21.12 
22.07 
23.04 


7.5625 
7.9102 
8.2656 
8.6289 


5.9396 
6.2126 
6.4918 
6.7771 


8.6394 
8.8358 
9.0321 
9.2285 








144 




3§k 



Square and Round Bars — Continued 



Thickness 

or 
Diameter 
in Inches 


Weight of 
■ Bar 

One Foot 
Long 


Weight of 
• Bar 

One Foot 
Long 


Area of 

■ Bar 

in Square 

Inches 


Area of 

• Bar 

in Square 

Incnes 


Circumfer- 
ence of 
• Bar 

in Inches 


3 

A 
i 
A 


30.60 
31.89 
33.20 
34.55 


24.03 
25.05 
26.08 
27.13 


9.0000 
9.3789 
9.7656 
10.160 


7.0686 
7.3662 
7.6699 
7.9798 


9.4248 
9.6212 
9.8175 
10.014 


A 

t 
A 


35.92 
37.31 
38.73 
40.18 


28.21 
29.30 
30.42 
31.55 


10.563 
10.973 
11.391 
11.816 


8.2958 
8.6179 
8.9462 
9.2806 


10.210 
10.407 
10.603 
10.799 


i 
A 

■A 


41.65 
43.15 
44.68 
46.23 


32.71 
33.89 
35.09 
36.31 


12.250 
12.691 
13.141 
13.598 


9.6211 
9.9678 
10.321 
10.680 


10.996 
11.192 
11.388 
11.585 


i 
* 


47.82 
49.42 
51.05 
52.71 


37.55 

38.81 
40.10 
41.40 


14.063 
14.535 
15.016 
15.504 


11.045 
11.416 
11.793 
12.177 


11.781 
11.977 
12.174 
12.370 


4 
. A 

A 


54.40 
56.11 
57.85 
59:62 


42.73 
44.07 
45.44 
46.83 


- 16.000 
16.504 
17; 016 
17.535 


12.566 
12.962 
13.364 
13.772 


12.566 
12.763 
12.959 
13.155 


A 

i 

A 


61.41 
63.23 
65.08 
66.95 


48.24 
49.66 
51.11 
52.58 


18.063 
18.598 
19.141 
19.691 


14.186 
14.607 
15.033 
15.466 


13.352 
13.548 
13.745 
13.941 


i 
A 
f 

14 


68.85 
70.78 
72.73 
74.71 


54.07 
55.59 
57.12 

58.67 


20.250 
20.816 
21.391 
21.973 


15.904 
16.349 
16.800 
17.257 


14.137 
14.334 
14.530 
14.726 


A 

J 
ii 


76.71 

78.74 
80.80 
82.89 


60.25 
61.85 
63.46 
65.10 


22.563 
23.160 
23.766 
24.379 


17.721 
18.190 
18.665 
19.147 


14.923 % 
15.119 
15.315 
15.512 


5 
A 

A 


85.00 
87.14 
89.30 
91.49 


66.76 
68.44 
70.14 
71 86 


25.000 
25.629 
26.266 
26.910 


19.635 
20.129 
20.629 
21.135 


15.708 
15.904 
16.101 
16.297 


i 

A 

1 
A 


93.71 
95.96 
98.23 
100.5 


73.60 
75.37 
77.15 

78.95 


27.563 
28.223 
28.891 
29.566 


21.648 
22.166 
22.691 
23.221 


16.493 
16.690 
16.886 
17.082 








145 


Digitize 







Squab 


B and Round Bars 1 — Continued 




Thickness 

or 
Diameter 
in Inches 


Weight of 
■ Bar 

One Foot 
Long 


Weight of 
• Bar 

One Foot 
Long 


Area of 

. BBar 

in Square 

Inches 


Area of 
• Bar 
in Square 

Inches 


Circumfer- 
ence of 
• Bar 
in Inches 


5 A 
I 


102.9 
105.2 
107.6 
110.0 


80.78 

82.62 
84.49 
86.38 


30.250 
30.941 
31.641 
32.348 


23.758 
24.301 
24.851 
25.406 


17.279 
17.475 

17.672 
17.868 




112.4 
114.9 
117.4 
119.9 


88.29 
90.22 
92.17 
94.14 


33.063 
33.785 
34.516 
35.254 


25.967 
26.535 
27.109 

27.688 


18.064 
18.261 
18.457 
18.653 


6 
A 
i 
A 


122.4 
125.0 
127.6 
130.2 


96.13 
98.15 
101.8 
102.2 


36.000 
36.754 
37.516 
38.285' 


28.274 
28.867 
29.465 
30.069 


18.850 
19.046 
19.242 
19.439 


1 
A 

A 


132.8 
135.5 
138.2 
140.9 


104.3 
106.4 
108.5 
110.7 


39.063 
39.848 
40.641 
41.441 


30.680 
31.296 
31.919 
32.548 


19.635 
19.831 
20.028 
20.224 


1 

A 
i 
ii 


143.7 
146.5 
149.2 
152.1 


112.8 
115.0 
117.2 
119.4 


.42.250 
43.066 
43.891 
44.723 


33.183 
33.824 
34.472 
35.125- 


20.420 
20.617 
20.813 ' 
21.009 


i 

M 
J 
if 


154.9 

157.8 
1G0.7 
1G3.6 


121.7 
123.9 
126.2 
128.5 


45.563 
46.410 
47.266 
48.129 


35.785 
36.451 
37.122 
37.800 


21.206 
21.402 
21.599 
21.795 


7 
A 

A 


166.6 
169.6 
172.6 
175.6 


130.8 
133.2 
135.6 
138.0 


49.000 
49.879 
50.766 
51.660 


38.485 
39.175 
39.871 
,40.574 


21.991 

22.188 
22.384 
22.580 


i 

A 


178.7 
181.8 
184.9 
188.1 


140.4 

142.8 
145.2 
147.7 


52.563 
53.473 
54.391 
55.316 


41.283 
41.997 
42.718 
43.446 


22.777 
22.973 
23.169 
23.366 


A 

i 


191.3 
194.5 
197.7 
200.9 


150.2 
152.7 
155.3 
157.8 


56.250 
57.191 
58.141 
59.098 


44.179 
44.918 
45.664 
46.415 


23.562 
23.758 
23.955 
24.151 


1 

i 

H 


204.2 
207.5 
210.9 
214.2 


160.4 
163.0 
165.6 

168 .2 


60.063 
61.035 
62.016 
63 004 


47.173 
47.937 
48.707 
49.483 


24.347 
24.544 
24.740 
24.936 



146 



Digitized by VJ vJvJ V LV^ 



Square and Round Bars — Continued 



Thickness 

or 
Diameter 
in Inches 


Weight of 
■ Bar 

One Foot 
Long 


Weight of 
• Bar 

One Foot 
Long 


Area of 

■ Bar 

in Square 

Inches 


Area of 

• Bar 

in Square 

Inches 


Circumfer- 
ence of 
• Bar 

in Inches 


8 

A 

i 
A 


217.6 
221.0 
224.5 

227.9 


170,. 9 

173.6 
176.3 
179.0 


64.000 
65.004 
66.016 
67.035 


50.266 
51.054 
51.849 
52.649 


25.133 
25.329 
25.526 
25.722 


i 

A 
i 

A 


231.4 
234.9 
238.5 
242.1 


181.8 
184.5 
187.3 
190.1 


68.063 
69.098 
70.141 
71 . 191 


53.456 
54.269 
55.088 
55.914 


25.918 
26.115 
26.311 
26.507 


A 

i 


245.7 
249.3 
252.9 
256.6 


192.9 
195.8 
198.6 
201.5 


72.250 
73.316 
74.391 
75.473 


56.745 
57.583 
58.426 
59.276 


26.704 
26.900 
27.096 
27.293 


J 


260.3 
264.0 
267.8 
271.6 


204.4 
207.4 
210.3 
213.3 


76.563 
77.660 
78.766 
79.879 


60.132 
60.994 
61.863 
62.737 


27.489 
27.685 

27.882 
28.078 


9 

A 
I 
A 


275.4 
279.2 
283.1 
287.0 


216.3 
219.3 
222.3 
225.4 


81.000 

82.129 
83.266 
84.410 


63.617 
64.504 
65.397 
66.296 


28.274 

28.471 
28.667 
28.863 • 


1 

A 
i 

A 


290.9 . 
294.9 

298.8 
302.8 


228.5 
231.6 
234.7 

237.8 


85.563 
86.723 
87.891 
89.066 


67.201 
68.112 
69.029 
69.953 


29.060 
29.256 
29.453 
29.649 


A 

t 


306.9 
310.9 
315.0 
319.1 


241.0 
244.2 
247.4 
250.6 


90.250 
91.441 
92.641 
93.848 


70.882 
71.818 
72.760 
73.708 


29.845 
30.042 
30.238 
30.434 


i 


323.2 
327.4 
331.6 
335.8 


253.8 
257.1 
260.4 
263.7 


95.063 
96.285 
97.516 
98.754 


74.662 
75.622 
76.589 
77.561 


30.631 
30.827 
31.023 
31.220 


10 

A 

A 


340.0 
344.3 
348.6 
352.9 


267.0 
270.4 
273.8 
277.1 


100.00 
101.25 
102.52 
103.79 


78.540 
79.525 
80.516 
81.513 


31.416 
31.612 
31.809 
32.005 


i 

A 
1 


357.2 
361.6 
366.0 
370.4 


280.6 
284.0 
287.4 
290.9 


105.06 
106.35 
107.64 
108.94 


82.516 
83.525 
84.541 
85.563 


32.201 
32.398 
32.594 
32.790 



117 



Square and Round Bars — Continued 



Thickness 

or 
Diameter 
in Inches 


Weight of 
■ Bar 

One Foot 
Long 


Weight of 
• Bar 

One Foot 
Long 


Area of 

■ Bar 

in Square 

Inches 


Area of 

• Bar 

in ►Square 

Inches 


Circumfer- 
ence of 
• Bar 
in Inches 


10 i 

1' 


374.9 
379.3 
383.8 

388.4 


294.4 
297.9 
301.5 
305.0 


110.25 
111.57 
112.89 
114.22 


86.590 
87.624 
88.664 
89.710 


32.987 
33.183 
33.380 
33.576 


i 

i 


392.9 
397.5 
402.1 
406.7 


308.6 
312.2 
315.8 
319.5 


115.56 
116.91 
118.27 
119.63 


90.763 
91.821 
92.886 
93.957 


33.772 
33.969 
34.165 
34.361 


u 
* 

i 
A 


411.4 
416.1 
420.8 
425.5 


323.1 
326.8 
330.5 
334.3 


121.00 
122.38 
123.77 
125.16 


95.033 
96.116 
97.206 
98.301 


34.558 
34.754 
34.950 
35.147 


1 


430.3 
435.1 
439.9 
444.8 


338.0 
341.7 
345.5 
349.3 


126.56 
127.97 
129.39 
130.82 


99.402 
100.51 
101.62 
102.74 


35.343 
35.539 
35.736 
35.932 


i 

f 

tt 


449.7 
454.6 
459.5 
464.4 


353.2 
357.0 
360.9 
364.8 


132.25 
133.69 
135.14 
136.60 


103.87 
105.00 
106.14 
107.28 


36.128 
36.325 
36.521 
36.717 


1 


469.4 
474.4 
479.5 
484.5 


368.7 
372.6 
376.6 
380.5 


138.06 
139.54 
141.02 
142.50 


108.43 
109.59 
110.75 
111.92 


36.914 
37.110 
37.307 
37.503 



From Handbook, Cambria Steel Co. 



Notes on Gearing. — Circular pitch = 



_ 3.1416 X dia. ins. 



; diaraet- 



number of teeth 
• • number of teeth 

ical pitch = dja of pitch circle in ing 

Formulae for Gears. Two gears are to run together, and for 
the large let D = diameter of pitch circle, D = whole diameter, 
N = number of teeth, V = velocity, and for the small d — diameter 
of pitch circle, d = whole diameter, n = number of teeth, v = veloc- 
ity. Also let a = distance between centers of the two wheels, 6 = 

number of teeth in both wheels. Then N= ^ ; n == — 1_; V = 

V v + V 

Vil - NV ♦ D'= 2av - D = 2ajnjf_2). , /= 2aV 
N ' n ' v+V ' 6 v+V 



* Brown and Sharpe Mfg. Co. 



148 



Digiti 



zed by G00gk 



Weights of Flat Rolled Steel Bars 

Pounds per Lineal Foot 

One cubic foot of steel weighs 489.6 pounds 

For thicknesses from ft in. to 2 ins. and widths from 1 in. to 12% ins. 



Thickness 
in Inches 


1* 


IK* 


IK 


IH" 


2* 


2X* 


2X* 


2X" 


12» 


ft 


.638 
.850 


.797 
1.06 


.956 
1.28 


1.12 
1.49 


1.28 
1.70 


1.43 
1.91 


1.59 
2.13 


1.75 
2.34 


7.65 
10.20 


A 

X 

ft 


1.06 
1.28 
1.49 
1.70 


1.33 
1.59 
1.86 
2.13 


1.59 
1.91 
2.23 
2.55 


1.86 
2.23 
2.60 
2.98, 


2.13 
2.55 
2.98 
3.40 


2*39 
2.87 
3.35 
3.83 


2.66 
3.19 
3.72 
4.25 


2.92 
3.51 
4.09 
4.68 


12.75 
15.30 
17.85 
20.40 


i 


1.91 
2.13 
2.34 
2.55 


2.39 
2.66 
2.92 
3.19 


2.87 
3.19 
3.51 
3.83 


3.35 
3.72 
4.09 
4.46 


3.83 
4.25 
4.68 
5.10 


4.30 
4.78 
5.26 
5.74 


4.78 
5.31 
5.84 
6.38 


5.26 
5.84 
6.43 
7.01 


22.95 
25.50 
28.05 
30.60 


IS 

a 
i 


2.76 
2.98 
3.19 
3.40 


3.45 
3.72 
3.98 
4.25 


4.14 
4.46 
4.78 
5.10 


4.83 
5.21 
5.58 
5.95 


5.53 
5.95 
6.38 
6.80 


6.22 
6.69 
7.17 
7.65 


6.91 
7.44 
7.97 
8.50 


7.60 

8.18 
8.77 
9.35 


33.15 
35.70 
38.25 
40.80 


1A 

IX 
1A 
IX 


3.61 
3.83 
4.04 
4.25 


4.52 
4.78 
5.05 
5.31 


5.42 
5.74 
6.06 
6.38 


6.32 
6.69 
7.07 
7.44 


7.23 
7.65 
8.08 
8.50 


8.13 
8.61 
9.08 
9.56 


9.03 

9.56 

10.09 

10.63 


9.93 
10.52 
11.10 
11.69 


43.35 
45.90 
48.45 
51.00 


1A 

IX 

1ft 


4.46 
4.68 
4.89 
5.10 


5.58 
5.84 
6.11 
6.38 


6.69 
7.01 
7.33 
7.65 


7.81 
8.18 
8.55 
8.93 


8.93 

9.35 

9.78 

10.20 


10.04 
10.52 
11.00 
11.48 


11.16 
11.69 
12.22 
12.75 


12.27 
12.86 
13.44 
14.03 


53.55 
56.10 
58.65 
61.20 


ltt 

1% 


5.31 
5.53 
5.74 
5.95 


6.64 
6.91 
7.17 
7.44 


7.97 
8.29 
8.61 
8.93 


9.30 

9.67 

10.04 

10.41 


10.63 
11.05 
11.48 
11.90 


11.95 
12.43 
12.91 
13.39 


13.28 
13.81 
14.34 
14.8a 


14.61 
15.19 
15.78 
16.36 


63.75 
66.30 
68.85 
71.40 


itt 

2 


6.16 
6.38 
6.59 
6.80 


7.70 
7.97 
8.23 
8.50 


9.24 

9.56 

9.88 

10.20 


10.78 
11.16 
11.53 
11.90 


12.33 
12.75 
13.18 
13.60 


13.87 
14.34 
14.82 
15.30 


15.41 
15.94 
16.47 
17.00 


16.95 
17.53 
18.12 
18.70 


73.95 
76.50 
79.05 
81.60 



149 



Digiti 



zed by G00gk 



Weights of Flat Rolled Steel Bars — Continued 



Thickness 
in Inches 



3K" 



S l A" 



WS 



±K" 



4W 



W 



\2" 



A 

X 

A 
H 
A 
H 

9 

% 
J* 

H 

Vs 

a 



1A 

1M 

1A 
i« 
1A 
1J* 

1A 
i% 
1H 
lJi 

1H' 
IK 
1H 

2 



1.91 
2.55 

3.19 

3.83 
4.46 
5.10 

5.74 
6.38 
7.01 
7.65 

8.29 

8.93 

9.56 

10.20 

10.84 
11.48 
12.11 
12.75 

13.39 
14.03 
14.66 
15.30 

15.92 
16.58 
17.21 
17.85 

18.49 
19.13 
19.76 
20.40 



2.07 
2.76 

3.45 
4. -14 
4.83 
5.53 

6.22 
6.91 
7.60 
8.29 

8.98 

9.67 

10.36 

11.05 

11.74 
12.43 
13.12 
13.81 

14.50 
15.19 
15.88 
16.58 

17.27 
17.96 
18.65 
19.34 

20.03 
20.72 
21.41 
22.10 



2.23 
2.98 

3.72 
4.46 
5.21 
5.95 

6.69 
7.44 
8.18 
8.93 

9.67 
10.41 
11.16 
11.90 

12.64 
13.39 
14.13 
14.88 

15.62 
16.36 
17.11 

17.85 

18.59 
19.34 
20.08 
20.83 

21.57 
22.31 
23.06 
23.80 



2.39 
3.19 

3.98 

4.78 

5 

6 

7.17 
7.97 

8.77 
9.56 

10.36 
11.16 
11.95 
12.75 

13.55 
14.34 
15.14 
15.94 

16.73 
17.53 
18.33 
19.13 

19.92 
20.72 
21.52 
22.31 

23.11 
23.91 
24.70 
25.50 



2.55 
3.40 

4.25 
5.10 
5.95 
6.80 

7.65 

8.50 

9.35 

10.20 

11.05 
11.90 
12.75 
13.60 

14.45 
15.30 
16.15 
17.00 

17.85 
18.70 
19.55 
20.40 

21.25 
22.10 
22.95 
23.80 

24.65 
25.50 
26.35 
27.20 



2.71 
3.61 

4.52 
5.42 
6.32 

7.22 

8.13 

9.03 

9.93 

10.84 

11.74 
12.64 
13.55 
14.45 

15.35 

16.26 
17.16 
18.06 

18.97 
19.87 
20.77 
21.68 

22.58 
23.48 
24.38 
25.29 

26.19 
27.09 
28.00 
28.90 



2.87 
3.83 

4.78 
5.74 
6.69 
7.65 

8.61 

9.56 

10.52 

11.48 

12.43 
13.39 
14.34 
15.30 

16.26 
17.21 
18.17 
19.13 

2Q.08 
21.04 
21.99 
22.95 

23.91 
24.86 
25.82 

26.78 

27.73 
28.69 
29.64 
30.60 



3.03 
4.04 

5.05 
6.06 
7.07 
8.08 

9.08 
10.09 
11.10 
12.11 

13.12 
14.13 
15.14 
16.15 

17.16 
18.17 
19.18 
20.19 

21.20 
22.21 
23.22 
24.23 

25.23 
26.24 
27.25 

28.26 

29.27 
30.28 
31.29 
32.30 



7.65 
10.20 

12.75 
15.30 
17.85 
20.40 

22.95 
25.50 
28.05 
30.60 

33.15 
35.70 
38.25 
40.80 

43.35 
45.90 
48.45 
51.00 

53.55 
56.10 
58.65 
61.20 

63.75 
66.30 

68.85 
71.40 

73.95 
76.50 
79.05 
81.60 



150 



Digiti 



zed by G00gk 



Weights op Flat Rolled Steel Bars — Continued 



Thickness 
in Inches 



5H" 



W 



5K" 



W 



GX" 



W 



12" 



A 
X 

A 
H 
A 
K 

A 

k 

» 

K 

H 

K 



1A 
IK 
1A 
IK 

1A 
IK 
1A 
IK 

1A 
IK 
1H 
IK 

1H 
IK 
1H 

2 



3.19 
4.25 

5.31 

6.38 
7.44 
8.50 

9. 50 
10.63 
11.69 
12.75 

13.81 

14.88 
15.94 
17.00 

18.06 
19.13 
20.19 
21.25 

22.31 
23.38 
24.44 
25.50 

26.56 
27.63 
28.69 
29.75 

30.81 
31.88 
32.94 
34.00 



3.35 
4.46 

5.58 
6.69 
7.81 
8.93 

10.04 
11.16 
12.27 
13.39 

14.50 
15.62 
16.73 
17.85 

18.97 
20.08 
21.20 
22.31 

23.43 
24.54 
25 .'66 
26.78 

27.89 
29.01 
30.12 
31.24 

32.35 
33.47 
34.58 
35.70 



3.51 
4.68 

5.84 
7.01 
8.18 
9.35 

10.52 
11.69 
12.86 
14.03 

15.19 
16.36 
17.53 
18.70 

19.87 
21.04 
22.21 
23.38 

24.54 
25.71 
26.88 
28.05 

29.22 
30.39 
31.56 
32.73 

33.89 
35.06 
36.23 
37.40 



3.67 
4 

6.11 
7.33 
8.55 
9.78 

11.00 
12.22 
13.44 
14.67 

15.88 
17.11 
18.33 
19.55 

20.77 
21.99 
23.22 
24.44 

25.66 
26.88 
28.10 
29.33 

30.55 
31.77 
32.99 
34.21 

35.43 
36.66 

37.88 
39.10 



3.83 
5.10 

6.38 

7.65 

8.93 

10.20 

11.48 
12.75 
14.03 
15.30 

16.58 
17.85 
19.13 
20.40 

21.68 
22.95 
24.23 
25.50 

26.78 
28.05 
29.33 
30.60 

31.88 
33.15 
34.43 
35.70 

36.98 
38.25 
39.53 
40.80 



3.98 
5.31 

6.64 

7.97 

9.30 

10.63 

11.95 
13.28 
14.61 
15.94 

17.27 
18.59 
19.92 
21.25 

22.58 
23.91 
25.23 
26.56 

27.89 
29.22 
30.55 
31.88 

33.20 
34.53 
35.86 
37.19 

38.52 
39.84 
41.17 
42.50 



4.14 
5.53 

6.91 

8.29 

9.67 

11.05 

12.43 
13.81 
15.19 
16.58 



4.30 
5.74 

7.17 

8.61 

10.04 

11.48 

12.91 
14.34 
15.78 
17.21 



17. 
19.34 
20.72 
22.10 

23.48 
24.86 
26.24 
27.63 

29.01 
30.39 
31.77 
33.15 

34.53 
35.91 
37.29 
38.68 

40.06 
41.44 
42.82 
44.20 



9618 



65 
20.08 
21.52 
22.95 

24.38 
25.82 
27.25 
28.69 

30.12 
31.56 
32.99 
34.43 

35.86 
37.29 
38.73 
40.16 

41.60 
43.03 
44.47 
45.90 



7.65 
10.20 

12.75 
15.30 
17.85 
20.40 

22.95 
25.50 
28.05 
30.60 

33 ..15 
35.70 
38.25 
40.80 

43.35 
45.90 
48.45 
51.00 

53.55 
56.10 
58.65 
61.20 

63.75 
66.30 
68.85 
71.40 

73.95 
76.50 
79.05 
81.60 



151 



Digiti 



zed by G00gk 



Weights op Flat Rolled Steel Bars — Continued 



Thickness 
in Inches 



7X" 



7H" 



7H" 



W 



8H* 



8K' 



12» 



X 
A 

H 

A 



K 

1 



1A 
i« 
1A 

IK 

1A 
1H 
1A 
1H 

1A 
1H 



2 



4.46 
5.95 

7.44 

8.93 

10.41 

11.90 

13.39 

14.88 
16.36 
17.85 

19.34 
20.83 
22.31 
23.80 

25.29 
26.78 
28.26 
29.75 

31.24 
32.73 
34.21 
35.70 

37.19 
38.68 
40.16 
41.65 

43.14 
44.63 
46.11 
47.60 



4.62 
6.16 

7.70 

9.24 

10.78 

12.33 

13.87 
15.41 
16.95 
18.49 

20.03 
21.57 
23.11 
24.65 

26.19 
27.73 
29.27 
30.81 

32.35 
33.89 
35.43 
36.98 

38.52 
40.06 
41.60 
43.14 

44.68 
46.22 
47.76 
49.30 



4.78 
6.38 

7.97 

9.56 

11.16 

12.75 

14.34 
15.94 
17.53 
19.13 



4.94 
6.59 

8.23 

9.88 

11.53 

13.18 

14.82 
16.47 
18.12 
19.76 



20.72 
22.31 
23.9lf24 
25.50 



21.41 
23.06 
24.70 
26.35 



27.09 
28.69 
30.28 

31.88 

33.47 
35.06 
36.66 
38.25 

39.84 
41.44 
43.03 
44.63 

46.22 
47.81 
49.41 
51.00 



28.00 
29.64 
31.29 
32.94 

34.58 
36.23 
37.88 
39.53 

41.17 

42.82 
44.47 
46.11 

47.76 
49.41 
51.05 
52.70 



5.10 
6.80 

8.50 
10.20 
11.90 
13.60 

15.30 
17.00 
18.70 
20.40 

22.10 
23.80 
25.50 
27.20 

28.90 
30.60 
32.30 
34.00 

35.70 
37.40 
39.10 
40.80 

42.50 
44.20 
45.90 
47.60 

49.30 
51.00 
52.70 
54.40 



5.26 
7.01 

8.77 
10.52 
12.27 
14.03 

15.78 
17 53 
19.28 
21.04 

22.79 
24.54 
26.30 
28.05 

29.80 
31.56 
33.31 
35.06 

36.82 
38.57 
40.32 
42.08 

43.83 
45.58 
47.33 
49.09 

50.84 
52.59 
54.35 
56.10 



5.42 
7.23 

9.03 
10.84 
12.64 
14.45 

16.26 
18.06 
19.87 
21.68 

23.48 
25.29 
27.09 
28.90 

30.71 
32.51 
34.32 
36.13 

37.93 
39.74 
41.54 
43.35 

45.16 
46.96 

48.77 
50.58 

52.38 
54.19 
55.99 
57.80 



5.58 
7.44 

9.30 
11.16 
13.02 

14.88 

16.73 
18.59 
20.45 
22.31 

24.17 
26.03 
27.89 
29.75 

31.61 
33.47 
35.33 
37.19 

39.05 
40.91 
42.77 
44.63 

46.48 
48.34 
50.20 
52.06 

53.92 
55.78 
57.64 
59.50 



7.65 
10.20 

12.75 
15.30 
17.85 
20.40 

22.95 
25.50 
28.05 
30.60 

33.15. 
35.70 
38.25 
40.80 

43.35 
45.90 
48.45 
51.00 

53.55 
56 . 10 
58.65 
61.20 

63.75 
66.30 
68.85 
71.40 

73.95 
76.50 
79.05 
81.60 



152 



Digiti 



zed by G00gk 



Weights op Flat Rolled Steel Bars — Continued 



Thickness 
in Inches 



W 



9X" 



W 



10* 



10K" 



10H" 



10M* 



12" 



ft 
ft 



ft 



lA 

lA 
lJi 

lA 
i» 
lA 

134 

1A 
i« 
1H 

1% 

1H 
i« 
1H 

2 



5.74 
7.65 

9.56 
11.48 
13.39 
15.30 

17.21 
19.13 
21.04 
22.95 

24.86 
26.78 
28.69 
30.60 

32.51 
34.43 
36.34 
38.25 

40.16 
42.08 
43.99 
45.90 

47.81 
49.73 
51.64 
53.55 

55.46 
57.38 
59.29 
61.20 



5.90 

7 

9.83 
11.79 
13.76 
15.73 

17.69 
19.66 
21.62 
23.59 

25.55 
27.52 
29.48 
31.45 

33.42 
35.38 
37.35 
39.31 

41.28 
43.24 
45.21 
47.18 

49.14 
51.11 
53.07 
55.04 

57.00 
58.97 
60.93 
62.90 



6.06 
8.08 

10.09 
12.11 
14.13 
16.15 

18.17 
20.19 
22.21 
24.23 

26.24 
28.26 
30.28 
32.30 

34.32 
36.34 
38.36 
40.38 

42.39 
44.41 
46.43 
48.45 

50.47 
52.49 
54.51 
56.53 

58.54 
60.56 
62.58 
64.60 



6.22 
8.29 

10.36 
12.43 
14.50 
16.58 

18.65 
20.72 
22.79 
24.86 

26.93 
29.01 
31.08 
33.15 

35.22 
37.29 
39.37 
41.44 

43.51 
45.58 
47.65 
49.73 

51.80 
53.87 
55.94 
58.01 

60.08 
62.16 
64.23 
66.30 



6.38 
8.50 

10.63 
12.75 

14.88 
17.00 

19.13 
21.25 
23.38 
25.50 

27.63 
29.75 

31.88 
34.00 

36.13 
38.25 
40.38 
42.50 

44.63 
46.75 
48.88 
51.00 

53.13 
55.25 
57.38 
59.50 

61.63 
63.75 
65.88 
68.00 



6.53 
8.71 

10.89 
13.07 
15.25 
17.43 

19.60 
21.78 
23.96 
26.14 

28.32 
30.49 
32.67 
34.85 

37.03 
39.21 
41.38 
43.56 

45.74 
47.92 
,50.10 
52.28 

54.45 
56.63 
58.81 
60.99 

63.17 
65.34 
67.52 
69.70 



6.69 
8.93 

11.16 
13.39 
15.62 
17.85 

20.08 
22.31 
24.54 

26.78 

29.01 
31.24 
33.47 
35.70 

37.93 
40.16 
42.39 
44.63 

46.86 
49.09 
51.32 
53.55 

55.78 
58.01 
60.24 
62.48 

64.71 
66.94 
69.17 
71.40 



6.85 
9.14 

11.42 
13.71 
15.99 
18.28 

20.56 
22.84 
25.13 
27.41 

29.70 
31.98 
34.27 
36.55 

38.83 
41.12 
43.40 
45.69 

47.97 
50.26 
52.54 
54.83 

57.11 
59.39 
61.68 
63.96 

66.25 
68.53 
70.82 
73.10 



7.65 
10.20 

12.75 
15.30 
17.85 
20.40 

22.95 
25.50 
28.05 
30.60 

33.15 
35.70 
38.25 
40.80 

43.35 
45.90 
48.45 
51.00 

53.55 
56.10 
58.65 
61.20 

63.75 
66.30 
68:85 
71.40 

73.95 
76.50 
79.05 
81.60 



153 



Digiti 



zed by G00gk 



Weights of Flat Rolled Steel Bars — Continued 



Thickness 
in Inches 



A 



k 

X 

H 

H 
tt 



1A 
V/s 
1A 
lJi 

1A 
i« 
1A 

1A 
i« 
Hi 
IX 

1H 

IK 

itt 

2 



11* 



7.01 
9.35 

11.69 
14.03 
16.36 
18.70 

21.04 
23.38 
25.71 
28.05 

30.39 
32.73 
35.06 
37.40 

39.74 
42.08 
44. 41 
46.75 

49.09 
51.43 
53.76 
56.10 

58.44 
60.78 
63.11 
65.45 

67.79 
70.13 
72.46 
74.80 



11M" 



7.17 
9.56 

11.95 
14.34 
16.73 
19.13 

21.52 
23:91 
26.30 
28.69 

31.08 
33.47 
35.86 
38.25 

40.64 
43.03 
45.42 
47.81 

50.20 
52.59 
54.98 
57.38 

59.77 
62.16 
64.55 
66.94 

69.33 
71.72 
74.11 
76.50 



IW 



7.33 

9.78 

12.22 
14.66 
17.11 
19.55 

21.99 
24.44 
26.88 
29.33 

31.77 
34.21 
36.66 
39.10 

41.54 
43.99 
46.43 

48.88 

51.32 
53.76 
56.21 
58.65 

61.09 
63.54 
65.98 
68.43 

70.87 
73.31 
75.76 
78.20 



llM" 



7.49 
9.99 

12.48 

14.98 
17.48 
19.98 

22.47 
24.97 
27.47 
29.96 

32.46 
34.96 
37.45 
39.95 

42.45 
44.94 
47.44 
49.94 

52.43 
54.93 
57.43 
59.93 

62.42 
64.92 
67.42 
69.91 

72.41 
74.91 
77.40 
79.90 



7.65 
10.20 

12.75 
15.30 

17.85 
2Q. 40 

22.95 
25.50 
28.0. r 
30.60 

33.15 
35.70 
38.25 
40.80 

43.35 
45.90 
48.45 
51.00 

53.55 
56.10 
58.65 
61.20 

63.75 
66.30 

68.85 
71.40 

73.95 
76.50 
79.05 
81.60 



12H" 



7.81 
10.41 

13.02 
15.62 

18.22 
20.83 

23.43 
26.03 
28.63 
31.24 

33.84 
36.44 
39.05 
41.65 

44.25 
46.86 
49.46 
52.06 

54.67 
57.27 

59.87 
62.48 

65.08 
67.68 
70.28 
72.89 

75.49 
78.09 
80.70 
83.30 



12^* 



7.97 
10.63 

13.28 
15.94 
18.59 
21.25 

23.91 
26.56 
29.22 
31.88 

34.53 
37.19 
39.84 
42.50 

45.16 
47.81 
50.47 
53.13 

55.78 
58.44 
61.09 
63.75 

66.41 
69.06 
71.72 
74.38 

77.03 
79.69 
82.34 
85.00 



12H" 



8.13 
10.84 

13.55 
16.26 

18.97 
31.68 



3g« 



c a r ~ 

11 



s: 



g>«eoS 
ft+* fcio 



* *.g ft 

*"' in O O 

Slat 

o 03 a 



154 



Digiti 



zed by G00gk 



METALS AND ALLOYS 155 

NON-FERROUS METALS AND ALLOYS 

Copper. — There are three recognized grades, viz., electrolytic, 
Lake, and casting. The first is refined by electrolytic methods 
and is very pure. Lake is also very pure in its natural or mineral 
state and requires simply to be melted down to bars for convenient 
handling. Casting copper contains more impurities and runs lower 
in conductivity than either electrolytic or Lake. 

Copper is very ductile and malleable and can be rolled into sheets, 
drawn into wire, or cast. Electric conductivity equal to that of 
silver fuses at around 1930° F. Cast copper tensile strength 25,000, 
elastic limit 6,000, copper plates, rods and bolts tensile strength 
33,500, elastic limit 10,000, annealed wire 36,000 tensile strength 
and elastic limit 10,000. Weight per cubic foot 554 lb. Sp. gr. 8.9. 

Aluminum. — A very light and non-corrosive metal that is soft, 
ductile and malleable. Is acted on by salt water. The tensile 
strength can be increased by cold rolling, and is about the same 
as for cast iron. Aluminum castings have a tensile strength of 
about 15,000 lb. and elastic limit 6,500, sheets 24,000 and 12,000, 
bars 28,000 and 14,000. Weight per cubic foot 159 lb. Sp. gr. 
2.56. Can be welded by electricity. 

Zinc is practically non-corrosive in the atmosphere, hence is 
suitable for a coating for iron and steel surfaces exposed to the 
weather. See Galvanizing. Is ductile and malleable but to a 
less extent than copper. Melts at 780° F. Weight per cubic foot 
436 lb. Sp. gr. 7.14. 

Lead is a very malleable and ductile metal, but it is difficult 
to draw it into wire. Is rolled in sheets and pipe. Has* a low 
tensile strength and elastic limit, hence lead pipes are only for 
low pressures. They are not affected by water containing car- 
bonates or sulphates as a film of insoluble salt is formed which 
prevents action. Tensile strength 1,600 to 2,400 lb. Melts at 
620° F. Weight per cubic foot 709 lb. Sp. gr. 11.07. 

Tin is a white malleable metal that is not oxidized by moist air. 
It melts at 450° F., and is often used for safety plugs in boilers 
and also for protecting iron and copper from moisture. Weight 
per cubic foot 455 lb. Sp. gr. 7.3. 

Bronzes. — Alloys of copper and tin with sometimes other metals 
added. Bronze as ordinarily understood is an alloy of copper 
and tin varying from 8 to 25% of tin. Average weight 530 lb. 
per cubic foot. Sp. gr. 8.62. Gun metal contains 8 to 10% tin, 

Digitized by VjiOOQ 1C 



156 SHIPBUILDING MATERIALS 

and the metal in bells 25%. Cast gun metal, according to U. S. 
Navy Dept. specifications, contains 87-89% copper, 9-11% tin, 
1-3% zinc, iron not to exceed .06% and lead not over .2%. 
Minimum tensile strength 30,000 lb. 

Phosphor Bronze. — The strength varies with the percentage of 
copper, tin, lead and phosphorus. The following may be taken 
as a fair average, 82.2% copper, 12.95% tin, 4.28% lead and .52% 
phosphorus. Stems, sternposts and outboard castings of sheathed 
and composite vessels are made of it. It is harder, closer-grained 
and stronger than Admiralty bronze, has a tensile strength of 
about 50,000, elastic limit 24,000. Weight per cubic foot 508 lb. 
Sp. gr. 8. 

Admiralty Bronze for propeller blades, etc., in the British Navy, 
is a mixture of 87% copper, 8% tin and 5% zinc. Average tensile 
strength 32,000 lb., with an elongation of 7J^% in 2 ins. Sp. gr: 
8.66. 

Titan Bronze is an alloy of copper and zinc having the color of 
gold. Can be forged from a cherry red heat down to a black heat, 
while ordinary brass is only slightly malleable. It resists corro- 
sion better than brass and is suitable for pump plungers, propeller 
bolts, motor boat shafts, etc. Castings have a tensile strength of 
60,000 to 63,000 lb., elastic limit 35,000 to 40,000 lb. per square 
inch, elongation 15 to 20% in 2 ins.' May be obtained in bars, in 
which case it has a tensile strength of 70,000 to 80,000, elastic 
limit 40,000 to 48,000, elongation 40% in 2 ins., reduction of area 
45 to 50%. 

Tobin Bronze is not affected by salt water, hence is suitable for 
propeller shafts of motor boats, valve stems and for other pur- 
poses where a strong material is required that is not acted on by 
salt water. Contains 59 to 63% copper, % to 1H% tin and re- 
mainder zinc. Tensile strength 60,000 to 65,000, compression 
170,000 to 180,000. Weight per cubic foot 525 lb. Sp. gr. 8.4. 

Manganese Bronze contains 56% copper, about 41% zinc and 
small quantities of iron, tin, aluminum and manganese. Used for 
outboard castings of sheathed and composite vessels. Tensile 
strength 60,000. 

Brasses. — These consist of alloys of copper and zinc, the per- 
centage of zinc varying from 10 to 50%. Brass castings have a 
tensile strength of 26,000 to 31,000 lb., but when the percentage 
of zinc exceeds about 45% the tensile strength falls off to around 
20,000. Average weight per cubic foot 505 lb. Sp. gr. 8.10. 



ioogle 



WOOD 



157 



Muntz Metal is a brass containing 60% copper and 40% zinc. 
When rolled and annealed it has the properties of steel, being both 
malleable and strong, having a tensile strength of 50,000 to 65,000. 

Naval Brass contains 62% copper, 36 to 37% zinc and 1 to l l A% 
tin. Is not affected by salt water. When rolled into rods accord- 
ing to the U. S. Navy requirements it must show a tensile strength 
of at least 60,000, an elastic limit of at least l A the ultimate strength 
and an elongation of not less than 25% in two inches. 

Common Allots 



Alloy 

Admiralty bronze 

Aluminum bronze 

Babbitt (light) 

Babbitt (heavy) 

Brass (common yellow metal) 

Brazing metal 

Gun metal 

Manganese bronze 

Muntz metal 

Navy brass 

Navy composition 

Parsons white metal. , 

Phosphor bronze 

Steam metal 

Tobin bronze. 

White metal 



Proportions 



Copper 87, tin 8, zinc 5 

Copper 89 to 98, aluminum 11 to 2 

Copper 1.8, tin 89.3, antimony 8.9 

Copper 3.7, tin 88.9, antimony 7.4 

Copper 65.3, zinc 32.7, lead 2 

Copper 84, zinc 16 

Copper 89, zinc 2.75, tin 8.25 

Copper 88.64, zinc 1.57, tin 8.7, iron 

.72, lead .3 
Copper 60, zinc 40 
Copper 62, zinc 37, tin 1 
Copper 88, zinc 2, tin 10 
Copper 1.68, zinc 22.9, tin 72.9, lead 

1.68, antimony .84 
Copper 90 to 92, phosphide of tin 

10 to 8 
Copper 85, tin 6.5, zinc 4.5, lead 4.25 
Copper 59 to 61, tin 1 to 2, zinc 37 

to 38, iron .1 to .2, antimony .30 

to .35 
Antimony 12, lead 88 



Weights of Copper and Brass Sheets, see pages 126 and 127. 



WOOD 

Sawing. — The manner in which lumber is sawed has considerable 
influence on its qualities. By flat sawing is meant cutting the 
timber tangential to the annual rings. Rift or quarter sawing is 
cutting the boards out of a log so the annular rings are cut as nearly 
as possible in a radial direction. Flat sawing and rift sawing 
give rise in the trade to the terms "flat grain" and "edge grain" 



Jle 



158 



SHIPBUILDING MATERIALS 



respectively. Rift sawing is done for the sake* of the beauty of 
the grain, and furthermore the lumber shrinks less, does not sliver, 
and wears more evenly and smoother than flat grain. 

All timber when first cut contains a large quantity of moisture 
that must be got rid of by seasoning. Seasoning is either by 
natural means, as by leaving the timber exposed to a free circu- 
lation of air, or by artificial, as by putting it in a kiln. As a whole 
the former gives better results than the latter. The drier the 
timber the less likely it is to shrink and decay. 

In general, the term "soft wood" is given to all trees of the 
coniferous or needle-leaved family, as pines, firs, spruces, hemlocks, 
cypress, larch, redwood, cedars, etc. The term "hard wood" is 
commonly applied to the broad-leaved family, as oaks, maples, 
hickories, elms, basswood, beech, walnut, birch, etc. In the U. S. 
Forestry Service hardness is determined by the weight required to 
force a steel ball .444 of an inch in diameter one-half its diameter 
into the wood. Tests of woods are given in the following table, 
the species being arranged from the softest to the hardest as ex- 
pressed by the pressure in pounds necessary to make the required 
indentation. 

As no two trees of the same species are exactly alike, the weights, 
strength, and other properties as given in the tables may vary 
within rather wide limits, so in making comparisons and in all 
strength calculations an ample factor of safety should be taken. 

Hardness of Various Woods 

Pressure in pounds required to indent specimen to depth of one- 
half diameter of a .444-inch diameter steel ball. 

Soft Woods 



Fir, Alpine 219 

Spruce, Englemann. . , 243 

Cedar, Western Red 246 

Cedar, Northern White. . . 266 

Pine, White 296 

Pine, Lodgepole 315 

Pine, Western Yellow 320 

Pine, Sugar 324 

Fir, White 328 

Pine, Table Mountain .... 333 



Pine, Norway 342 

Spruce, Red 346 

Cypress 354 

Tamarack 375 

Fir, Grand 375 

Hemlock, Eastern 406 

Douglas Fir ,408 

Hemlock, Black 464 

Pine, Longleaf 512 



Average hardness, 340 

Digitized by LiOOQ 1C 



HARD WOOD SIZES 



159 



Hard Woods 



Basswood 

Buckeye, Yellow. 
Willow, Black . . . 

Butternut 

Cherry, Red 

Elm, White 

Ash, Black 

Sycamore 

Maple, Silver 

Maple, Red 

Cherry, Black . . . 

Tupelo 

Birch, Yellow 



242 
286 
334 
386 
386 
511 
548 
580 
592 
612 
664 
700 
745 



Ash, Pumpkin 

Beech 

Maple, Hard 

Elm, Rock 

Ash, White 

Oak, Red 

Oak, White 

Oak, Swamp White . 
Laurel, Mountain. . . 

Dogwood. 

Locust, Black 

Locust, Honey 

Osage, Orange 



752 

824 

882 

888 

941 

982 

1063 

1158 

1299 

1408 

1568 

1846 

2037 



Average hardness, 844 



Hard Wood Sizes 

The standard sizes adopted by the National Hardwood Lumber 
Association are as follows: 

Standard lengths are 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 and 16 
ft., but not over 15% of odd lengths are admitted. 

Standard thicknesses are H, %, A, %, %, 1, 1^, IK, 1%, 2, 
2J4 3, SA, 4, 4^, 5, 5A and 6 ins. 

Standard thicknesses for surfaced lumber are: 



Rough 



Surfaced 



% ins. S-2-S* to A ins. 

A " A 

% " A 

K " A 

1 " tt 

1A " 1A 

VA " 1H 



Rough 



Surfaced 



VA ins. S-2-S to 1^ ins. 

2 " lJi 

2H " 2H 

3 " 2% 

*A " ZH 

4 " 3% 



* S-2-S signifies surfaced on 2 sides. 

Lumber surfaced one side only must be A inch full of the 
above thicknesses. 

The standard sizes for hardwood lumber surfaced two sides 
adopted by the Hardwood Manufacturers' Association are as above, 
except that these manufacturers work %-in. stock to A-in. instead 
of A-in. 

Digitized by VjiOOQIC 



160 SHIPBUILDING MATERIALS 

Soft Wood Sizes 

The standard lengths of soft woods are commonly in multiples 
of 2 ft., beginning at 4 or 6 ft., and standard widths in multiples 
of 2 ins., beginning at 4 ins. 

Common Woods. 1 — Ash, white and red, the former often used for 
oars, is close grained, takes a good polish and warps very little. 
Weight per cubic foot 43 to 45 lb. Sp. gr. .75. Crushing strength 
along the fiber in pounds per square inch, 5,000 to 9,000. 

Balsa, very light-; life preservers are sometimes made of it. 

Black walnut, heavy, strong and durable; for cabinet work and 
interior, decoration. Weight per cubic foot 38 lb. Sp. gr. .61. 

Cedar (red), fine grained, strong, easily split, especially durable 
in contact with water. Used for planking in high grade motor 
boats. Weight per cubic foot 20 to 25 lb. Sp. gr. .33. There is 
also a white cedar that is soft, light and fine grained but lacking the 
strength and toughness of the red. 

Cherry, for interior finish, has a close fine grain, and is very 
durable. Weight per cubic foot 42 lb. Sp. gr. ^70. 

Chestnut, comparatively soft, close grained, is brittle, but is 
durable when exposed to the weather. Weight per cubic foot 
28 lb. Sp. gr. .45. 

Cork, a tree growing in Southern Europe, the bark of which is 
used in life preservers and for insulation purposes in refrigerating 
rooms. To avoid sweating in cabins below a steel deck the plating 
may be coated with granulated cork. First a coat of sticky varnish 
is applied, then the cork dusted thickly over it and painted with 
two or three coats of white paint. Weight per cubic foot 15.6 lb. 
Sp. gr. .24. 

Cypress, light, hard, close grained and durable, adapted for both 
outside and inside work. Weight per cubic foot 30 lb. Sp. gr. .48. 

Douglas fir. — This term covers the timber known as yellow fir, 
red fir, western fir, Washington fir, Oregon or Puget Sound fir, 
northwest and west coast fir. Crushing strength parallel to grain 
2,920 lb. per square inch. Weight per cubic foot 34 lb. Sp. gr. 
.54. Douglas fir is exceptionally strong for its weight, is durable 
and does not shrink much. 

1 Note. — Only those are given that are common in ship construction. The 
specific gravity and weight of the same wood varies; the value given is a fair 
average for seasoned wood. The moisture contents varies in seasoned timber from 
15 to 20% and in green timber up to 50%. Sp. gr. and weight from 10th U. 8. 
Census. 

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HACKMATACK 161 

Hackmatack, a strong wood for knees connecting beams and 
frames of wood vessels. Weight per cubic foot 35 to 40 lb. Sp. 
gr. .59. 

Lignum vitas, hard, strong and close grained with fibers running 
radially and tangentially. Is resinous and is difficult to split. 
Is used in ship's blocks, and stern and outboard bearings. Tensile 
strength along the fiber 14,800 lb. per square inch, crushing 7,000. 
Weight per cubic foot 60 to 65 lb. Sp. gr. 1.14. 

Locust has a peculiar striped grain, is hard, and is suitable for 
exposed places where great durability is required. Weight per 
cubic foot 46 lb. Sp. gr. .73. 

Mahogany, hard, close grained, difficult to split, takes a fine 
polish. The straight-grained varieties are little affected by the 
weather,- although the cross varieties warp and twist. Used for 
planking in high speed motor boats, deck houses, etc., and interior 
finish. Weight per cubic foot 46 lb. Sp. gr. .73. The soft and 
inferior grades from Honduras and Mexico are called baywood. 

Maple, light colored, fine grained, strong and heavy, used for 
interior trim. Weight per cubic foot 43 lb. Sp. gr. .68. 

Oak (white), very durable, largely employed in wood vessels 
for frames and beams, can be steamed and bent. Is not suit- 
able for steel vessels as it contains an acid which attacks the steel. , 
Weight per cubic f6ot 46 lb. Sp. gr. .74. 

Oak (live), the strongest of the oaks, seldom comes in long 
straight pieces. Weight per cubic foot 59 lb. Sp. gr. .95. 

Pine, long-leaf or Southern pine, hard and strong, extensively * 
used for decks. Weight per cubic foot 44 lb. Sp. gr. .70. 

Pine (Oregon) — same as Douglas fir. See above. 

Pine (short-leaf), much resembling long-leaf, but inferior to it. 
Suitable for interior finish, flooring, etc. Weight per cubic foot 
38 lb. Sp. gr. .61. North Carolina pine is the trade name given, 
to that species of short-leaf pine known as the loblolly. 

Pine (white), light, very strong and easily worked. Weight 
per cubic foot 26 lb. Sp. gr. .41. 

Poplar or whitewood, light, brittle and warps if weather changes. 
Is cheap and easy to work. Weight per cubic foot 30 lb. Sp. gr. .48. 

Spruce, light, strong, tougher and more durable than white . 
pine. Varieties: black, white and red. Norway spruce or white 
deal has a tough, straight grain which makes it an excellent ma- 
terial for masts. Spars, paddles and oars are often made of spruce. 

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162 SHIPBUILDING MATERIALS 

Black spruce is used for wharf piling. Weight per cubic foot 27 
lb. Sp. gr. .4 to .46. 

Teak, a heavy, strong wood suitable for railings, armor backing, 
etc., does not readily split nor warp when exposed to alternate 
moisture and dryness. Will stand heavy wear, and contains a 
resinous oil which prevents the rusting of steel and iron when in 
contact with it. Weight per cubic foot 52 lb. Sp. gr. .82. 

Physical tests, see Strength of Materials. 

Feet board measure, see page 9. 

Shipping weights, see page 18. 

MISCELLANEOUS NON-METALLIC MATERIALS 

Oakum. — Consists of hemp fibers obtained from old rope. For 
caulking decks with oakum a light one-handed mallet is employed, 
the caulker hitting a thin flat chisel, forcing the oakum between 
the planks. In heavy work, as in the outside planking as a final 
operation, a large horsing mallet is used. After the deck seams 
are caulked, the oakum being slightly below the surface of the 
planks, they are payed, i. e., hot pitch is poured into the seams. 
Oakum is put up in standard bales weighing 50 lb. gross. 

Caulking Cotton. — For caulking yachts and motor boats where 
the planking is thin, instead of oakum. 

Portland Cement.^-When mixed with sand and water is laid as 
a covering for the shell plating in the inner bottom. It not only 
protects the plating against the corrosive action of foul bilge water 
but against the erosive action of hard substances which may be 
washed about. In oil tankers the cement may be omitted, but 
vessels carrying sugar and copper ore should have a thick coat. 
Portland cement is not readily affected by ordinary substances 
but is softened by sulphate of ammonia. When laid, say 1J^ ins. 
thick, the proportion should be 3 parts of sand to 1 of cement, 
"but if less thickness is required the proportion may be as 2 to 1. 
Pure Portland cement weighs about 120 lb. per cubic foot; if laid 
with sand, 128 lb. See also Structural Details. 

Insulating Materials. — These are magnesia, asbestos, cork and 
hair felt — the two former for covering hot surfaces, as steam pipes 
and boilers, and the two latter for cold pipes, as those containing 
brine. 

Magnesia is the best non-conducting material and is the most 
expensive. In combination with asbestos as 85% magnesia and 
15% asbestos it can be obtained in a variety of forms as in sec- 
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ASBESTOS 163 

tional pipe covering, blocks, sheets and cement. A bag of 85% 
magnesia weighs 60 lb. and will cover approximately 40 sq. ft. 
one inch thick. 

Asbestos will soften when in contact with water and should 
not be used where parts are subject to moisture as under the engine 
room floor plates or on cold water pipes. It can be obtained in 
sectional pipe covering, blocks, sheets and cement. A bag of 
asbestos cement weighs 100 lb. and will cover about 40 sq. ft. one 
inch thick. 

Either cork or hair felt may be fitted around cold water and 
brine pipes but should not be on steam. Cork may be obtained 
in the granulated form or in sheets. Hair felt comes in rolls \i, 
14, % 1 and 1 Yz ins. thick by 6 ft. wide, and after being put around 
a pipe is covered with canvas. See Refrigeration. 

Mineral Wool, a fibrous material made from blast furnace slag, 
is a good non-combustible covering, but is brittle and liable to 
fall to powder where much jarring exists. 

Air space alone is one of the poorest non-conductors, though 
the best owe their efficiency to the numerous minute air cells in 
their structure. This is seen in the value of different forms of 
carbon, from cork charcoal to anthracite dust, the former being 
three times as valuable, though in chemical constitution they are 
practically identical. 

Based on one inch thickness, the approximate efficiencies of the 
following coverings referred to bare pipes are — asbestocel, 76.8%, 
magnesia, 83.5%, asbestos, Navy brand, 82%. 

Steam Pipe Covering is made in standard lengths 3 ft. long, 
which when placed around a pipe are fastened on by brass bands; 
in addition canvas may be sewed around them. The best and most 
expensive is magnesia, which has high non-conducting qualities 
and is also very light. Next to this are asbestos sheets made 
into pipe form so there are air cells, thus giving (as air is an excel- 
lent non-conductor of heat) a cheap and efficient covering. For 
high-pressure steam piping 85% magnesia is used, while for lower 
pressure and exhaust piping asbestos with air cells, about one inch 
thick, answers. Valves and fittings are covered with cement, and in 
some instances the flanges have coverings that can be easily removed. 
Boiler Covering. — For the best results on high temperatures 
1J^- to 2-inch magnesia blocks are wired on, and finished with a 
coat of magnesia cement. A cheaper covering for pressures over 
125 lb. may consist of 2-inch asbestos blocks, covered with wire 
mesh and finished with a 3^-inch coat of cement. 



y Google 



164 



SHIPBUILDING MATERIALS 



Cylinders may be covered with asbestos or magnesia blocks 
wired on and then inclosed* in teak or mahogany vertical strips 
secured with brass bands. Sheet iron is sometimes put on instead 
of wood strips. 

Abstract of Specifications Issued by U. S. Navy Department 



Part 


Covering 


Lagging 


Main cylinders and valve* chests. 

• 
Upper cylinder heads 


Magnesia 
Magnesia 

Magnesia 

Magnesia 
2}^ ins. 


Lagged all over with 

galvanized sheet iron 

Neatly fitted iron floor 


Steam and exhaust pipes, valves, 
fittings and flanges, separators, 
feed water heaters 

Boiler drums 


plates, with flat top- 
ped corrugations 

t 

Canvas sewed on and 
painted 







Magnesia for lagging, and in uptakes, smoke pipes, etc., will be 
composed as follows: 

Carbonate of magnesia 85% 

Asbestos fiber 15% 

Canvas on pipes 2 ins. dia. and smaller 8 oz. per yard 

Canvas on pipes above 2 ins. dia., separators, etc. 15 oz. per yard 



Tests of Insulating Materials 









Transmission 






Transmission 


in B.t.u. per 






in B.t.u. per 


Square Feet 




Thick- 


Square Feet 


per Degrees F. 


Material 


ness 


per Degrees F. 


Difference in 




Inches 


Difference in 


Temperature 
per One Inch 






Temperature 
per 24 Hours 






Thickness 








per 24 Hours 


Composition cork board (granu- 








lated cork and asphalt) 


2 


4.5 


9 


Slag wool in board form, some- 








times called rock cork 


2 


3.8 


7.6 


Nonpareil cork board 


1 


6.2 


6 2 


Nonpareil cork board 


2 


3. 


6 


Nonpareil cork board 


3 


2.2 


6 6 







Google 



NON-CONDUCTING MATERIALS 



165 



Percentage of Heat Transmitted Through Various Pipe 
Coverings 

(The heat loss from an uncovered pipe is taken as 100%) 



Substance 



Heat Low 
Per Cent. 



Pipe without covering 

Pipe painted with black asphaltum 

Pipe painted with light drab lead paint 

Pipe painted glossy white 

Asbestos paper, two layers one inch hair felt canvas covered 

Asbestos paper, 4 thicknesses 

Asbestos paper, 2 thicknesses. 

Asbestos, molded, mixed with plaster of Paris.' 

Asbestos and wool felt 

Magnesia, molded, applied in plastic form 

Magnesia as a class 

Mineral wool as a class 

Rock wool as a class 

Fossil meal as a class , 



100 
105 
107 
95 
15 
50 
75 
30 
20 
25 
20 
20 
22 
25 



From Plumbers' Handbook, Int. Text Book Co. 



Table of Relative Value of Non-Conducting Materials 



Substance 



Value 



Loose wool 

Geese feathers 

Felt, hair, or wool 

Carded cotton 

Mineral wool 

Carbonate of magnesia 

Rice chaff, loose 

Paper 

Cork 

Sawdust 

Wood ashes 

Wood across grain 

Coal ashes 

Asbestos, paper 

Asbestos, fibrous 

Air space undivided. . . 
Sand 



3.35 

1.08 

1.00 

1.00 

.68 to .83 

.67 to .76 

.76 

.74 

.71 

.68 

.61 

.40 to .55 

.35 to .49 

.47 

.36 

.14 to .22 

.17 



.50 to 
.61 to 



From Handbook, Lukens Iron & Steel Co. 



Digiti 



zed by G00gk 



SECTION IV 
SHIP CALCULATIONS 

Length over all is* the length measured from the foremost tip of 
the stem bar to the aftermost tip of the overhang of the stern. 

Length between Perpendiculars. — For vessels with straight 
vertical stems, the length between perpendiculars is taken from the 
fore side of the stem bar to the aft side of the stern post. When 
the stem is raked, that is, inclined forward, the length is measured 
from the fore side of the stem bar at the upper deck. Should the 
vessel have a clipper or curved stem, the length is measured from 
the point where the line of the upper deck beams would intersect 
the fore edge of the stem if it were produced in the same direction 
as the part below the cutwater. 

Lloyd's Length is measured from the fore part of the stem to the 
after part of the stern post on the range of the upper deck beams 
except in awning or shelter-deck vessels, in which cases the length 
is measured on the range of the deck beams next below the awning 
or shelter deck. In vessels in which the stem forms a cutwater the 
length is measured from the point where the upper-deck beam line 
would intersect the fore edge of the stem if it were produced in the 
same direction as the part below the cutwater. In vessels having 
cruiser sterns, the length is taken as 96% of the extreme length 
from the fore part of the stem on the range of the upper-deck 
beams to the aftermost part of the cruiser stern, but it is not to be 
less than the length from the fore part of the stem to the after 
side of sternpost when fitted, or to the fore side of the rudder stock 
when a sternpost is not fitted. 

Length for Tonnage. — See Registry. 

Extreme breadth is measured over the outside plating at the 
greatest breadth of the vessel. 

Breadth molded is taken over the frames at the greatest breadth. 

166 

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DEPTH OF HOLD 



167 



jrfw/r/fff or S/t*/jherhecA or 3r/afoe2>ec£< 






3 




Figure 18 

Depth, Lloyd's (molded) (Fig. 18) is measured at the middle of 
, the length from the top of keel to the top of beam at the side of the 
uppermost continuous deck, except in awning or shelter-deck 
vessels, where it may be taken to the deck next below the awning 
or shelter deck, provided the height of 'tween-decks does not exceed 
8 ft. When the height of 'tween-decks exceeds 8 ft. the depth is to 
be measured from top of keel to a point 8 ft. below the awning or 
shelter deck. 

Depth of Hold is measured from top of ceiling at the middle of 
the length in vessels with ordinary floors or from top of ceiling on 
double bottoms if ceiling is laid, or when no ceiling is laid from the 
tank top plating to the top of the beams of the first deck. Two 
and a half inches is the usual allowance for the ceiling. 

Draft — Most vessels have their draft load line parallel to the 
keel so that the draft at any point is the same, but in vessels with 
a drop or drag keel the draft is taken from the lowest point of the 
drag. The actual or extreme draft includes the depth of the keel. 
Figures which are placed at the bow and stern for indicating draft 
read to the lowest point of the figure and are 6 ins. high; so if the 



ile 



168 



y 



SHIP CALCULATIONS 



water was half way up on 10, the draft would be 10 ft. 3 ins. or if 
just covering it, 10 ft. 6 ins. 

Extreme Proportions. — A vessel is said to have extreme propor- 
tions when her length exceeds eleven times her molded depth. In 
such a vessel additional longitudinal strength is required. 

Displacement is the amount of water displaced by a vessel. If 
she is floating in equilibrium in still water, the weight of water she 
displaces equals the weight of the vessel herself with everything on 
board. The displacement in cubic feet when floating in salt water 
divided by 35, and when floating in fresh water divided by 36, 
gives the total weight of a ship and her cargo in tons; as 35 cu. ft. 
of salt water weighs 1 ton (2240 lb.) and 36 cu. ft. of fresh water 
the same amount. 

The displacement of a steel vessel is calculated to the molded 
lines, and, as a rule, no allowance is made for the thickness of the 



7b/ts soo 




Figure 19.— Curves of Displacement and Dead Weight* 

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CURVE OF DISPLACEMENT 169 

shell plating, although the excess of water displaced by the shell 
amounts to about 1% of the total. For wooden vessels (motor 
boats, tugs, lighters, etc.) the displacement is calculated to the 
outside of the planking. On the Great Lakes (United States) the 
displacement is calculated in tons of 2000 lb., elsewhere in tons of 
22401b. 

Displacement = dead weight X 1.64 (approximately). 

For calculation of displacement see "Displacement Sheet." 

A curve of displacement (see Fig. 19) can be plotted as follows: 
Lay off on the line OL to any convenient scale the draft in feet of 
the vessel, as 1, 2, 3, etc., and draw in the water lines. On the 
load-water line lay off to any convenient scale divisions representing 
tons, the distance WL representing the displacement at the load- 
water line, WL' the displacement at the second water line, and so 
on. A curve drawn through the points W, W' t etc., to O is the 
curve of displacement. From this curve, knowing the draft, any 
displacement can be readily obtained. 

Dead weight is the carrying capacity and includes the tons of 
cargo and generally the coal. The dead weight equals about 64% 
of the displacement. 

The registry of a vessel as prescribed by the U. S. Treasury 
Department, Revised Statutes, Section 4150, is as follows: 

The registry of every vessel shall express her length and breadth, together with 
her depth and the height under the third or spar deck, which shall be ascertained 
in the following manner: The tonnage deck in vessels having three or more 
decks shall be the second deck from below; in all other cases the upper deck is the 
tonnage deck. The length from the fore part of the outer planking on the side of 
the stem to the after part of the main stern-post of screw steamers and to the 
after part of the rudder-post of all other vessels measured on the top of the tonnage 
deck shall be accounted the vessel's length. The breadth of the broadest part on 
the outside of the vessel shall be accounted the vessel's breadth of beam. A 
measure from the under side of the tonnage-deck plank, amidships, to the ceiling 
of the hold (average thickness) shall be accounted the depth of the hold. If the 
vessel has a third deck, then the height from the top of the tonnage deck plank to 
the under side of the upper-deck plank shall be accounted as the height under the 
spar deck. All measurements to be taken in feet and fractions of feet, and all 
fractions of feet shall be expressed in decimals. 

Register ton measurement is the measurement based on a ton of 
2240 lb. occupying 100 cu. ft. 

Gross tonnage is the measurement in register tons of the interior 
capacity of the entire ship. 

Net tonnage is the tonnage in register tons upon which payment 

Digitized by vjOOQ LC 



170 SHIP CALCULATIONS 

is made, and is the «pace available for cargo and passengers. 
Roughly, for freight steamers, if the net tonnage is multiplied by 
2.5, the tons of cargo that can be carried are obtained. This 
assumes that the cargo occupies 40 cu. ft. per ton. For calculation 
of tonnage for vessels using the Suez Canal, see " Suez Canal 
Tonnage Rules," published by Board of Trade, London; and for 
those using the Panama Canal see " Panama Canal Rules," 
published by the Treasury Department, Washington. 

Cubic Capacity. — When the term " cubic capacity cargo space " 
is used, this is taken as the cubic capacity of the cargo holds cal- 
culated to the molded lines of the vessel. Cubic grain measure- 
ment is sometimes taken one or two inches inside the molded lines. 
Cubic bale measurement is generally understood as being to the 
bottom of the deck beams and to the inboard face of the reverse 
frames. 

Tons per Inch of Immersion. — It is often necessary to find the 
distance a vessel will sink when known weights are placed on board, 
or how much she will rise if weights are removed. 

If A is the area of a water plane in square feet, then the displace- 
ment of a layer 1 ft. thick, supposing the vessel to be parallel sided, 

is A X 1 = A cu. ft., or ^r tons in salt water. For a layer \ in. 

oO 

thick, the displacement is „, 19 tons, and this is the number of 

tons that must be placed on board to make a vessel sink 1 in., or 
the number of tons to be removed to lighten her 1 in. 

Examples. — (1) A steamer 350 ft. long, 45 ft. beam, has a draft of 20 ft. How 
many tons must be placed on board to make her sink 1 in.? 

First find the area of the water plane, assuming a coefficient of fineness of the 

water plane as .85. Then the area is 

.85 X 350 X 45 = 13,387.5 sq. ft. 

_ . , . . . area of water plane 13,387.5 0< _ . 
Tons per inch of immersion = * = — j^n — = 31 -8 tons - 

Therefore, when the steamer is drawing 20 ft., 31.8 tons would have to be placed 
aboard to make her sink 1 in. 

(2) At a draft of 16 ft., the tons per inch of immersion of a steamer are 12.5. If 
75 tons of cargo were removed, find the decrease in draft and the new draft. ' 

Decrease in draft = ■-%-? = 6 ins. 
u.o 

New draft = 16 fl*6 ins. = 15 ft. 6 ins. 

A curve of tons per inch of Immersion (see Fig. 20) can be 
plotted as follows: Lay off on the line OL to any convenient scale 

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TONS PER INCH OF IMMERSION 



171 



the draft in feet of the vessel, as 1, 2, 3, etc. (in a large vessel take 
water lines say 4 ft. apart), and draw in the water lines. On the 
water lines lay off to any convenient scale divisions representing tons, 
that must be added to make the vessel sink 1 in. A curve through 
the points is the curve of tons per inch of immersion. 




fO // fz /3 Tons 

Figurj 20.— Curve of Tons per Inch of Immersion. 

Approximate Formulae for Tons per Inch of Immersion. — Let 
L = length of water line in ft.; 
B = beam in ft. 



For fine vessels, tons per inch of immersion 
For medium vessels, tons per inch of immersion 
For cargo vessels, tons per inch of immersion 



LXB 

600 
LXB 

550 
LXB 

500 



The coefficient of fineness of water plane is the ratio of the area, 
of the water plane to the circumscribing rectangle. For ships with 
fine ends this is 0.7; for ships of ordinary form, 0.75; for ships with 
bluff ends, 0.8 to 0.89. 

Prismatic coefficient is the ratio between the volume of the dis- 
placement and a solid having a transverse area equal to the area of 
the immersed midship section multiplied by the length taken for 
calculating the displacement. 

Digitized by LiOOQ LC 



f 



Y72 # SHIP CALCULATIONS 

The coefficient of fineness of midship section is the ratio of the 
area of the immersed midship section to the area of its circumscribing 
rectangle. The coefficient for ordinary ships varies from .85 to .95, 
the latter value being for a section with a very flat bottom. 

The block coefficient is the ratio of the volume of the displace- 
ment to the volume of a block having the same length, breadth and 
mean draft. Below are the block coefficients of various types of 
vessels: 

Barges 85 to .9 

Very full cargo vessels up to 8 knots .8 to .85 

Full cargo vessels up to 12 knots 76 to .82 

Large cargo vessels up to 12 to 14 knots 7 to . 76 

Intermediate cargo and coastwise vessels 65 to . 7 

Fast Atlantic liners 6 to . 65 

English Channel passenger steamers 5 to. 6 

Steam trawlers, tugs 56 to ^6 

Paddle passenger steamers 46 to .57 

Battleships 6 to . 65 

Cruisers 48 to .55 

Torpedo boats and destroyers 4 to .48 

Sailing vessels 6 to .72 

Steam yachts 45 to .6 

Sailing yachts 3 to .52 

Above coefficients from Design and Cons, of Ships, J. H. Biles. 

Wetted Surface is the area of the immersed portion of a vessel. 

Let W = displacement in tons; L — length of vessel in ft.; 

D — mean draft in ft.; V =» volume of displacement in cu. ft. 

V 
Wetted surface in sq. ft.-1.7LXD + j; 

or - 15.5 VW X L, 

or - (LxBXl.7) + (LXBXblockcoefficient); 



or 



^F«(a.4+2^=) 



Center of Buoyancy is the center of gravity of the displaced 
water and is determined solely by the shape of the under water 
portion of a ship's hull. For calculations see " Displacement Sheet." 

In vessels of ordinary form the vertical position of the center of 
buoyancy below the foad-water line varies from .4 to .45 of the 
mean draft to the ttrp of the keel, the latter (.45) being the value 
in. vessels of full form. For yachts and vessels of unusual shape 
the above approximate rule does not apply. 



Digitized 



by Google 



TRANSVERSE METACENTER 



173 



Morrish's approximate formula for the distance of the center of 
buoyancy below the load-water line is as follows: 

Let V = volume of displacement up to the load-water line in 
cu. f t. ; A =» area of load-water plane in sq. ft. ; d — mean draft to 
top of keel in ft. 

Then the center of buoyancy below the load-water line =■ 



\32 ^ Af 



To find the fore and aft position of the center of buoyancy of a 
vessel, having given the areas of equidistant cross sections. Lay 
off a table as below which is of a vessel with cross sections 9.5 feet 
apart, the position of the center of buoyancy being desired from 
the middle station, that is, No. 5. 



Station 


Area 

of 

Section 


Simpson's 
Multi- 
pliers 


Functions 

of 

Area 


Number of 

Intervals 

from Middle 

Station 


Moments 


1 


1.2 
17.6 
41.6 
90.7 

134.3 

115.4 

61.7 

30.4 

6.6 


1 

4 
2 
4 

2 

4 
2 
4 

1 


1.2 

70.4 

83.2 

362.8 

268.6 

661.6 

123.4 

121.6 

6.6 


4 
3 
2 

1 



1 
2 
3 
4 


4.8 


2 


211.2 


3 


166.4 


4 


362.8 






5 


745.2 






6 


661.6 


7 


246.8 


8 


364.8 


9 


26.4 








1699.4 


1299.6 



Excess of products aft = 
Volume of displacement cubic feet = 
Then center of buoyancy aft of middle 
station or ordinate 5 = 



1299.6-745.2 = 554.4 
M X 9.5 ft. X 1699.4 

HX9.5X 9.5 X 554.4 



MX9.5X 1699.4 
« 3.9 ft. 

Transverse Metacenter. — Assume that a vessel is floating in still 
water under normal conditions (see Fig. 21), W L being the water 
line, B the center of buoyancy, and<G the common center of gravity 
of the hull, engines, boilers and all other weights on the vessel. 

Digitized by VJiOOQLC 



174 



SHIP CALCULATIONS 




, FIgTn*81 

If the vessel is inclined at a small angle, then W U is the 
new water line, and the new volume of displacement has its 
center of buoyancy at B'. The upward force of buoyancy acts 
through B\ while the weight of the ship acts vertically down through 
G, the center of gravity. The vertical line through B' cuts the center 
line of the vessel at M , and this point M is called the meta- 
center and the distance G M the transverse metacentric height. 

Table of Metacentric Heights 



Type of Ship 


Value of 0. M. 


Harbor vessels, as tugs 


15 to 18 ins. 


Small cruisers 


2 ft. to 2 ft. 6 ins. 


Battleships 


4 ft. to 5 ft. 


Shallow draft gunboats for river use 

Merchant steamers 


12 ft. 

1 ft. to 3 ft. 


Sailing vessels % 


3 ft. to 3 ft. 6 ins. 







See also table on Merchant Vessels and table in paragraph To Find Vertical 
Position of the Center of Gravity. 

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HEIGHT OF METACENTER 175 

A ship with a large transverse metacentric height comes to the 
upright position very suddenly, while a ship with a small one comes 
to the upright position more slowly and is more comfortable in a 
seaway. 

Referring to the figure it will be noted that the weight of a vessel 
acting vertically downward through the center of gravity, and the 
buoyancy of the water acting vertically upward through the new 
center of buoyancy form a couple. Draw G Z perpendicular to 
B' M. Then G Z is the arm of the couple, and the moment ot 
the couple is W X G Z. 

If G is below M the ship is in stable equilibrium. 
If G is above M the ship is in unstable equilibrium. 
If G coincides with M the ship is in neutral or indifferent equi- 
librium. 

For small angles up to 10° to 15°, M practically remains in a 
constant position, hence G Z — G M X sin 8. As G Z is the arm 
of the couple, then the moment of the couple is W X G M X sin 8, *- \{ jL y 
and if M is above G, this moment tends to right the ship, and is 
called the moment of statical stability at the angle 8. 

The above is called the metacentric method of determining a ' 
vessel's stability, and can only be used for small angles up to 15°. 
For larger angles cross curves of stability are calculated. (See 
section on Cross Curves.) 

. Example. A vessel 250 ft. long having a displacement of 3300 tons has a meta- 
centric height of 2 ft. 6 ins. What is her righting moment if she is inclined at an 
angle of 12 degrees? 

Righting moment = W XO M X Bin 

- 3300 X 2.5 X sin 12° = 1715 ft.-tons. 

To Find Height of Metacenter Above the Base Line. — The follow- 
ing formula* gives the height with a fair degree of accuracy. 

Let H = draft in feet , 
B = beam in feet 

a = a coefficient varying between .57 and .54, depending on 
the coefficient of fineness and exact shape of lines, and decreasing 
for the same vessel about .01 as the draft increases from 12 ft. 
to 24 ft. The values .57 to .54 are for coastwise passenger and 
freight steamers of modern design, having a fine load water line 
forward and full midship section. 

* From International Marine Engineering, New York. 



Digiti 



zed by G00gk 



176 



SHIP CALCULATIONS 



C = coefficient of .078 to .082 for coastwise passenger and 
freight steamers. 

Then the height of the metacenter above the base = a X H -\- 
CX B* 

H ' 

To Find the Moment of Inertia of a Water Plane About the Center 
Line. — Divide the length of the plane into a convenient number of 
parts and arrange a table as follows: 



Number 

of 
Ordinate 


Semi- 
ordinates of 
Water Planes 


Cubes of 

Semi- 
ordinates 


Simpson's 
Multipliers 


Functions 

of 

Cubes 


1 

2 

3 
• 4 
etc. 






1 

4 
2 
4 

etc. 





The sum of the functions of cubes X H the common distance the 
ordinates are apart X H X 2 (as only semi-ordinates were taken) 
= the moment of inertia of the water plane about its center line. 

Approximate Formula for the Moment of Inertia of a Ship's Water 
Plane About the Center Line. 

Let L = length in feet 
B = beam in feet 
n = coefficient for ships with fine water-line planes .04 

coefficient for ships with moderate water-line planes .05 
coefficient for ships with very full water-line planes .06 
J = moment of inertia 
Then / = n L B* 



Formula for Finding the Distance of the Transverse Metacenter 
above the Center of Buoyancy. 

/ = moment of inertia of water plane about its center line 
V = volume of displacement in cubic feet 



Then B M = y. 



See Displacement Sheet. 



Digiti 



zed by G00gk 



DISPLACEMENT SHEET 177 

Approximate Formula for the Distance of the Transverse Meta- 
center above the Center of Buoyancy. 

The formula for the transverse metacenter is B M = -y 

Let B — beam in feet 

D — molded draft in feet 

a = # a coefficient of .08 to .1 (say .09 for a vessel with 

a block coefficient of .75) 

B 2 
Then B M - a X -^ 

Displacement Sheet. — The procedure outlined below is the one 
usually employed in calculating the displacement, centers of buoy- 
ancy and metacenters. 

On a profile of a vessel drawn to a convenient scale, say H in. = 
1 ft. for small, and \i in. = 1 ft. for large, divide the distance be- 
tween the forward and after perpendiculars into any number of 
even parts. At these divisions erect perpendiculars, take cross 
sections, lay out a body plan and on it draw water lines. In the 
displacement calculations made for the tug on page 180, 10 sections 
or ordinates were taken with half-ordinates at both ends, the ordi- 
nates being 9.5 ft. apart. The water lines were spaced 2 ft. apart, 
with a one-foot water line between the base line and second water 
line. Half-ordinates and an additional water line were taken so 
the calculations would be close. 

Rule a sheet as shown on page 180 and write in a horizontal 
row the figures 1, 2, 4, etc., for the water lines and below Simpson's 
multipliers as H, 2, 1% 4, etc. In the vertical column at the left 
write the numbers of the ordinates as 1, 1J^, 2, etc., and in the next 
column Simpson's multipliers as J^, 2, 1J^, 4, etc. From the body 
plan scale the distances from the center line to the intersection at 
the second water line and write it down (generally in red ink) 
under 2 water line as .10; do this for the 1J^ ordinate which is .33, 
and so on for alt the water lines. 

Multiply the Simpson's multipliers below the water lines by 
the half-breadths and write the products below. Thus .10 X 1J^ 
= .15, .33 X lj^ = .50, etc. Add these products horizontally for 
each ordinate as for No. 1, .15 + .4 + .2 -f .4 -f .1 = 1.25 and 
write the sum in the column functions of areas. Multiply the func- 
tions of areas by Simpson's multipliers as J^, 2, 1J^, 4, etc., writing 
the products in the column multiples of areas. Add up this column 

Digitized by VJiOOQ 1C 



178 



SHIP CALCULATIONS 



which in the present case is 3256 and multiply it by }4 of each in- 
terval and by }4 of the distance the water lines are apart, thus, }£ 
X 2 ft. X H X 9.5 ft. X 2 (as half-breadths were taken), which will 
give the volume of the displacement in cubic feet as 13748, and 
to convert it into salt water tons divide by 35, as 35 cu. ft. of salt 
water weigh one ton. 

To find the fore and aft center of buoyancy, multiply the multiples 
of areas by their lever arm from the midship ordinate, thus giving 
forward and after moments as .60 X 5 = 3., 35.22 X4H = 158.49, 
etc. Add up the forward moments and the after ones. In the pres- 
ent case the after sum or 3287.92 is the largest, so subtract the 
forward from it leaving a remainder of 617.95. Multiply 617.95 
by 9.5 ft., the distance the ordinates are apart, and the product 
divided by the sum of the multiples of areas will give the location 
of the center of buoyancy; in the present vessel it is aft of No. 6, 
the midship ordinate, a distance of 1.83 ft. 

t- To find the vertical position of the center of buoyancy, multiply 
the half-breadth as for 2 W. L. at No. 1, viz.: .10 by Simpson's 
multiplier J^ giving .50; do the same for the next half-breadth, 
as .33 by 2, giving .66, writing the products in the column to the 
right and so on. Continue thus for the other water lines, and add 
up each as 2.75, 133.33, 170.90, etc., multiplying them by Simp- 
son's multipliers as }4, 2, 1%, 4, etc., the products being 1.37, 
246.66, 256.35, etc. Take moments about the base line which is 
with arms H, 1, 2, 3, etc., the sum of which is 9416.47. Multiply 
9416.47 by the distance the water lines are apart or 2 ft., and divide 
by the sum of the multiples of areas, the quotient being 5.78 ft., 
which is the distance the center of buoyancy is above the base line. 

The'above calculations may be simplified by using a planimeter 
for getting the areas of the cross sections. Thus for the displace- 
ment lay off a table as below: 



Station 


Reading of 
Planimeter 


Simpson's 
Multipliers 


Functions of 
Areas 


1 

2 

etc. 




2 
etc. 





Then instrument scale constant X sum of functions of areas 
X M common interval X 2 (if only half-areas of sections were 

Digitized by VjiOOQ 1C 



CENTER OF BUOYANCY 



179 



taken) = volume of displacement in cubic feet, which divided by 
35 will give the displacement in salt water tons. 

To find the fore and aft center of buoyancy use a table as follows: 



Station 


Planimeter 
Reading 


Simpson's 
Multipliers 


Functions 
of Areas 


Arms 


Functions 
of Moments 


Sum of 
Functions 














Forward 
Aft 



difference between sum of functions of moments X interval 



= distance 



sum of functions of areas 
center of buoyancy is from the station the moments were taken 
about. If the after moments are the greatest then the center of 
buoyancy will be aft of the station taken, and if less then forward 
of it. 
* To find the vertical center of buoyancy lay off a table thus: 



Water 
Plane 


Reading of 
Planimeter 


Simpson's 
Multipliers 


Functions 
of Areas 


Arms Above 
Base Line 


Functions of 
Moments 


1 

2 
etc. 












sum of functions of moments X distance water planes are apart 



sum of functions of areas 
distance center of buoyancy is above the base line. 

For the metacenters lay off a table as on page 181. To find the 
transverse metacenter multiply the cubes of the ordinates or half- 
breadths by tSimpson's multipliers as l A, 2, 1J^, 4, etc, writing 
the products in the column of functions of cubes. Take the sum 
of this column which is 34488.92 and multiply it by % of the dis- 
tance the ordinates are apart, which in the present case is 9.5 ft. 
also by }4 and by 2 (if half-breadths were taken) giving a product 
of 69359.21, which is the moment of inertia J of the water plane 
about its fore and aft center line. The distance between the trans- 
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182 SHIP CALCULATIONS 

verse center of buoyancy and transverse metacenter B M is given 

by the formula B M = -~?> / being the moment of inertia of the 

water plane as just found and V the volume of the displacement in 

cubic feet. Thus BM = i = 69 f Q 5 , 9 ; Q 21 = 5.04 ft. 
V Io74o 

To find the longitudinal metacenter multiply the functions of 
ordinates by the arms or levers there are from the midship ordinate, 
writing the product in the column Functions for Center of Gravity 
of Water Plane. Add up the forward and after functions, and as 
the after in the present vessel is the largest, subtract the forward 
from it, giving a remainder of 105.82. Multiply 105.82 by the 
distance the ordinates are apart, viz.: 9.5 ft., and divide the 
product by the sum of the functions of ordinates 289.12, the quo- 
tient being the distance the center of gravity of the water plane is 
aft of No. 6 ordinate. 

Multiply the functions for the center of gravity of the water 
plane by the arms 5, 4J^> 4, etc., writing the products in the column 
of functions for moment of inertia, the sum of the products being 
1758.32. 

As the longitudinal metacenter is to be referred to the center 
of gravity of the load water plane, a correction is necessary to the 
sum of the functions for moment of inertia, viz., 1758.32. 

Let / = moment of inertia about the middle ordinate 

y = distance the center of gravity is from the middle ordi- 
nate 
A — sum of the functions of ordinates X H distance ordi- 
nates are apart 
Then the new moment of inertia I around the center of gravity of 
the water plane is given by the expression I = I — Ay* 

By referring to page' 181 the various calculations are shown, 
giving a value of I as 982923. Hence if B M is the distance be- 
tween the longitudinal center of buoyancy and the longitudinal 
metacenter, I the moment of inertia as just found and V the vol- 
ume of the displacement in cubic feet, then B M = -^ and sub- 

982923 
stituting in this formula the values previously found \ojaq ^ en 

the quotient is 64.2 ft., which is the longitudinal metacentric 
height. 

Digitized by LjOOQ IC 



CURVES OF STABILITY 183 

Curves of Stability.* — These are obtained by calculating and then 
plotting the length of the righting arm or lever at different angles 
of inclination of the vessel and drawing a curve through the points 
found. For these calculations there must be known: (1) the posi- 
tion of the center of buoyancy in the upright position; (2) the 
position of the center of gravity of the vessel; (3) the volume of 
the displacement; and (4) the value of the moment of transference 
of the immersed and emerged wedges parallel to the new water line. 

The resulting curves (see Fig. 22) are important and are often 
given to the captain so he will know the condition of his vessel 
under various loadings. (See Loading of Cargoes.) The minimum 
value of the distance between the center of gravity and metacenter* 
(G M) in steamers of medium size is about one foot when loaded 
with a homogeneous cargo that brings them to the load water line. 
For small cargo vessels the distance between the center of gravity 
and the metacenter should not be less than 9 ins. provided a right- 
ing arm of like amount is obtained at 30° to 40°. For sailing 
vessels a higher value of G M is required, the minimum being 3 ft. 
to 3 ft. 6 ins. with a homogeneous cargo. 

Referring to Fig. 22, the righting levers are given vertically 
and the angles of inclination of the ship given horizontally in de- 
grees. The important features in the curves are: the inclination 
of the curve to the base line at its origin, the angle at which the 
maximum inclination occurs, and the length of the righting lever 
at this angle. 

Increasing the beam of a vessel increases the initial stability 
but does not greatly influence the area inclosed by the curve of sta- 
bility or its range. 

Increasing the freeboard has no effect on the initial stability 
(supposing the increase of freeboard does not affect the position 
of the center of gravity), but it has a most important effect in 
lengthening out the curve and increasing its area. 

In the table in Fig. 22 various conditions of loading a steamer 
391 ft. 6 ins. long, 51 ft. 6 ins. beam, and 29 ft. 3 ins. deep are given. 

(1) In Curve A, the ship is light, water in boilers, but no cargo, 
bunker coal, stores or fresh water on board, and all ballast tanks 
empty. 

(2) B same as (1), but with bunker coal, stores and fresh water 
on board. 

(3) C ready for sea, water in boilers, bunker coal, stores and 
fresh water aboard, and the holds and 'tween-decks filled with a 

♦From Ship Cons, and Calculations, G. Nicol. OOS 




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184 



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CROSS CURVES OF STABILITY 



185 



homogeneous cargo of such a density as to bring the steamer to her 
summer load line. 

(4) D same as (3), with bunker coal, stores and fresh water 
consumed, approximating to the end of the voyage. 

(5) E ready for sea, water in boilers, bunker coal, stores and 
fresh water aboard, and all ballast tanks filled. 

(6) F same as (5), but with bunker coal, stores and fresh water 
consumed. 

(7) G same as (3), but loaded with a coal cargo, part of the 
'tween-decks empty. 

(8) H same as (7), but with bunker coal, stores and fresh water 
consumed. 

Cross Curves of Stability.* — These are calculated for two or three 
conditions as, when the vessel is light, loaded, and loaded with the 
bunkers empty. Select angles of inclination as 15°, 30°, 50°, 70° 
and 90°. Prepare body plans for the fore body (see Fig. 23) and 
after body, and draw on them the load water line and the inclined 
Make the calculation first for the loaded condition. 

X 




* From A class book on Naval Architecture, W. J. Lovet% igiti 



186 



SHIP CALCULATIONS 



Find the area of each section of immersion and emersion at the 
assumed inclination, by a planimeter preferably, altho these can be 
found by Simpson's rules. Mark the center of gravity of each 
section. Draw a line X X perpendicular to the inclined water 
plane. This is the line about which the moments of the wedges 
are taken. Prepare a table as follows for the submerged wedge. 



Ordinates 


Areas 


Simpson's 
Multipliers 


Products 


Levers 
About X X 


Moments 


1 
2 
3 
4 
5 
etc. 




1 

4 
2 
4 

2 
etc. 










s 


M 



M 
Distance of center of gravity of wedge from X X = -5- 

o 

Also find volume of wedge by multiplying S by J| common 
interval. Repeat this calculation for the emerged wedge. Lay out 
a table thus: 





Volume 


Levers About X X 


Moments 


Submerged wedge .... 
Emerged wedge 










St 


M 



Digiti 



zed by G00gk 



TO FIND THE AREA 



187 



Si is the difference between the volumes of the submerged and 
emerged wedges. Make a correction for the difference, laying out 
a table thus: 











s 




Leverage 


Moments 










a 
















a 












m 

§ 
o 


© 

a 

3 


I 
I 


i 


•43 

r 

a 

a3 


5 

j 


I 

© 
S 

1 


I 
i 


1 


1 

© 

a 


1 






1 














2 






4 














3 






2 














etc. 






etc. 
















5 


+ s 


1? 








• 










-E 






S)- 












The leverage is half the difference of the two ordinates. 
Total moment M ± Si X G 



Total volume of displacement 



= BR 




zed by G00gk 



188 



SHIP CALCULATIONS 



In Si X G note if the greater volume is on the emerged side and 
the center of gravity of it on the emerged side, then the moment 
obtained has to be deducted from the total moment. If the greater 
volume is on the submerged side and its center of gravity on the 
submerged side the moment has to be added to the total moment. 



GZ - B R—B G sin 6 

BR 

BM 



sin 



Proceed to find B R in the same manner for SO , 50°, 70° and 90°. 
Also find B R for other drafts for all the angles of inclination. 
When this is done the cross curves of stability may be constructed, 
by setting up at the different drafts the G Z found for the different 
inclinations. Run lines through each series of spots and these lines 
are the cross curves of stability. See Fig. 25. 




To construct stability curves (Fig. 26) lay off the inclinations 
15°, 30°, etc., horizontally and vertically the values of GZ as 
previously found. Draw curves through the points thus laid off. 

The cross curves show constant inclination at varying displace- 
ments. The stability curves show constant displacement at vary- 
ing inclinations. The cross curves show the value of the righting 
arm G Z. A curve of righting moments could also be made show- 
ing the foot-tons (the value of W [displacement] X G Z). In 
preparing the body plan the sections are drawn to the uppermost 
continuous deck. If a watertight poop, bridge or forecastle become 
immersed at the higher angles of inclination, the value of their 
buoyancy should be calculated. 

As the above curves have been considered with the vessel station- 
ary, they are called static curves. 



NOTES ON STABILITY 



189 



Notes on Stability. — For ordinary vessels the transverse meta- 
center remains practically unchanged up to 10° inclination. The 
value of G M should not be less than 10 ins. and have a righting 
arm of at least 10 ins. at 45°. 




An ordinary seagoing ship should have a range of stability of 
70°. Stability varies as the square of the breadth and inversely 
as the draft. A 300-foot steamer when loaded had a maximum 
righting lever of 8 ins., while a similar one under similar conditions 
but 2 ft. broader had a maximum righting lever of 12 ins. Free- 
board is an important factor in stability, as the stability imme- 
diately begins to decrease when the edge of the deck gets under 
water, so , that every additional inch of freeboard increases the 
vessel's range. 

Approximate Formula for Calculating Stability (G Z). 

Let = angle the vessel is inclined, that is, the angle between 
normal water line and the inclined 
G M = distance between the center of gravity and the 
metacenter 

B M = distance the metacenter is above the center of 
buoyancy, 
righting arm 



GZ - 
Then 

GZ - 



G M sin + ^ tan 2 sin 6 



Up to an angle of 30°, provided the ratio of the beam to the draft 
is not abnormally great, the above formulae may be used instead 
of the long stability calculations. The values at inclinations of 

Digitized by VJiOOQLC 



190 



SHIP CALCULATIONS 



10°, 15° and 20° are practically the same as obtained with the 
usual stability calculations. 

Trim is the difference between the forward and aft draft of a vessel. 
Thus, suppose a vessel draws 12 ft. forward and 15 ft. aft; then she 
is said to trim 3 ft. by the stern. 

Longitudinal Metacenter. — Let B (see Fig. 27) be the center of 
buoyancy when floating on an even keel, W L, and suppose the trim 
of the vessel to change, the displacement being the same, then Bi 
is the new center of buoyancy. Draw B\M a vertical line meeting 
B M at M . Then M is the longitudinal metacenter, and the dis- 
tance G M the longitudinal metacentric height. 




Figure 27 



Moment to Alter Trim One Inch. — Suppose a weight w is moved 
from w to w, then the change of trim = W Wi + LL\ = (Wi S + 
S Li) X tan — length of load water line X tan 0. 

The movement of the weight w causes the center of gravity of 
the vessel to move aft a distance Gi G. Let W = the displacement 
in tons, a = the distance the weight w is moved, then 



(?iG = (?MXtanH W £ a and tan 6 - 



change of trim 



W 



w X a 
WXGM 



length of load water line 

Change of trim in feet = length of load water line (L) X tan $ = 
L X w X a 
WXGM 



Digiti 



zed by G00gk 



CALCULATIONS FOR TRIM 191 

To get the moment to alter trim one inch substitute in w r , = 

change of trim ., , t . , , w X a A 

length of load line IT X G M L 

Therefore the moment to alter trim one inch = w Xa — T -j — 

WXGM 



LX12 



foot-tons. 



Example. A 350-ft. steamer, displacement 6700 tons at her designed draft, has 
a longitudinal metacentric height of 350 ft. If 10 tons of cargo in her forward 
hold was moved 100 ft. aft, find the change in trim. 

W X Q M 6700 X 350 
Moment to change trim one inch = = ■ * = 55.8 foot-tons. 

Li X 1« OOU X 1^ 

Moment aft from shifting cargo — 10 tons X 100 ft. = 1000 foot-tons. 

Hence change of trim aft = ' -- ■ = 17.9 ina 
55.8 

Approximate Calculations for Trim. — In the formula, moment 

W X G M 
to alter trim one inch = T foot-tons, if G M is assumed 

Li X 1^ 

to be equal to L the length of the ship, which is roughly true in 

the case of ordinary cargo vessels at their load displacements, the 

W 
trimming moment per inch becomes y^ foot-tons. 

Another approximate formula giving closer results than the 
above is the following: 

T = tons per inch of immersion 
A = area of load water plane in square feet 
L = length on the load water line in feet 
B = breadth of ship amidships in feet 
V = volume of displacement in cubic feet 
W = displacement in tons 

The height of the longitudinal metacenter above the center of 

A 2 X L 
buoyancy in ordinary cargo steamers is B M = .0735 fi 

™ *j- si %, i xxr vol. of displacement V 
assuming B M = G M , and as W = ~ = rr 

Digitized by VjiOOQIC 



192 SHIP CALCULATIONS 

WXGM 



LX 12 



Then the moment to alter trim one inch 

V x 07 o 5 A'XL 

35 BxF A* 30.9 X T 2 

t — +ty — .000175 -g- foot-tons, or « foot-tons. 

Another formula for the moment to alter trim one inch is 

length on water line X displacement 

n X draft 

where n for fine vessels = 190 

where n for ordinary = 180 

where n for cargo = 172 

To Estimate the Displacement of a Vessel when Floating Out of 
Her Designed Trim. 

T — tons per inch of immersion 

y = center of flotation aft of amidships in feet . 

L ~ length of vessel in feet 

Then the extra displacement for one foot of extra trim = 

Example. A steamer 350 ft. long, draws 17 ft. forward and 24 ft. 3 ins. aft, thus 
trimming 7 ft. 3 ins. by the stern. When loaded she trims 5 ft. by the stern. If 
the center of flotation is 14 ft. aft amidships, and the tons per inch of immersion 35, 
what is the steamer's displacement? 

At a draft of 20 ft. 1 H ins. I ' « — ' ' I ner displacement from the 

displacement curve is 5850 tons. 

12 X 35 X 14 
The displacement for one foot of extra trim = 5^ =" 16.8 tons, and 

for 2 ft. 3 ins. extra trim = 37.8 tons. 

Thus new displacement = 5850 + 37.8 » 5887.8 tons. 

To Find the Distance the Longitudinal Metacenter is Above the 
Center of Buoyancy. 

Let V = volume of displacement in cubic feet 

I = moment of inertia of water plane about a transverse 
axis passing through the center of flotation. 

Then the longitudinal metacentric height B M — ^. See Meta- 
centers, page 186. 

To Find the Trim Corresponding to any Mean Draft and Longitud- 
inal Position of the Center of Gravity by Trim Lines or Curves.*— 
See. Fig. 28. Draw a line W L to represent the mean draft for 

* From Ship Calculations and Cons., G. Nicol. 

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CALCULATIONS FOR TRIM 



193 



which the trim line is required. On this line a point B is taken 
as the longitudinal position of the center of buoyancy at a level 
keel, and a line N N is drawn representing the midship line of the 
vessel. Thus the distance B N represents the distance the center 
of buoyancy is from amidships, which in the present case is forward 
of it. 




The horizontal distance from B of the center of buoyancy of the 
vessel trimming 2 ft. by the stern is calculated as follows: 
Change of trim = length of water line X tan (for see Fig. 27) 
a — change of trim 
~~ length of water line 
Now G Gi equals nearly B Bi, or the distance between the cen- 
ters of buoyancy before and after the trim has been changed, so 
G Gi = B Bx = G M X tan 0. 
G M is approximately equal to the length of the ship L on the 

c hange of trim 
L 
, w change of trim , 2 ft. 
L X ^ = LX ~T 



water line, then substituting G M = L and tan 



G Gi = B Bx = G M X tan $ 



and in the present case this distance is set off from B. 

Next calculate the position of the center of buoyancy with the 
vessel trimming 4 ft. by the stern, the same method as just out- 
lined being used, and lay off this distance as B B 2 . 

At Bi and B 2 verticals are erected, and the corresponding trims 
(2 ft. and 4 ft.) laid off, the same scale being used. Through the 
points thus found and the point B a line is drawn, which is the trim 
line required. 

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194 SHIP CALCULATIONS 

For forward trims the trim line should be continued below its 
level line to indicate the movement of the center of buoyancy in 
that direction. It should be noted that the center of gravity and 
center of buoyancy are here assumed to travel the same distance 
when a change of trim takes place. This is not quite true as B is 
below G and therefore more remote from M , and moves a greater 
distance. For very accurate work the distance plotted from B 
towards W should be the calculated travel of the center of gravity 
plus B G X tan 0. It is not necessary to proceed to this refinement 
in ordinary cases, as the error involved is not worth considering. 

From the trim line just drawn can be determined any trim 
up to 4 ft. (other trims, as 6 ft., 8 ft., etc., could be plotted if de- 
sired), due to the movement of weights on board. For if the dis- 
tance the center of gravity travels aft on account of the movement 
of the weights be ascertained and plotted from B along the level line 
C, and a vertical line be erected to intercept the trim line at Z), C D 
must be the trim by the stern, as the center of buoyancy and center 
of gravity are always in the same vertical line. 

A trim line is only reliable at its own draft, and when the change 
of displacement is considerable a new curve is required. For 
ordinary purposes three conditions are sufficient, viz., load, ballast, 
and light. 

Effect of Flooding 'a Damaged Compartment. — To find the effect 
of a compartment being thrown open to the sea by collision or other 
accident, account must be taken not only of the water that would 
enter if the ship remained in her original position, but also of the 
additional water which will enter due to the heel, change of trim, 
and sinkage caused by such flooding. 

When the compartment is wholly under water, and the water 
is prevented from spreading by a watertight deck or inner bottom 
the effect is the same as of adding a weight in a known position. 

To Find the Trim when a Compartment is Flooded. — The weight 
of the water in the compartment up to the original water line should! 
be found and the parallel sinkage determined assuming the com- 
partment open to the sea and the admitted water placed with its 
center of gravity in the vertical plane containing the center of 
gravity of the added layer of displacement. This distance measured 
in the trim diagram above the height of the original water plane, 
will give the point from which the level line and corresponding trim 
fine should be drawn. The trim can then be obtained (as described 
in the paragraph on Trim Lines) by finding the travel aft of the 

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CALCULATIONS FOR TRIM 



i 
195 



center of gravity, assuming the weight to be translated to its true 
position. 

It will next be necessary to calculate the weight of water in the 
compartment, assuming the surface to rise to the level of the new 
draft, and to use it in the same way in another trim estimate. If this 
should differ much from the first calculation, it may be necessary 
to proceed to a third. 

Or instead of the above, which is the trim line method, first de- 
termine the amount of mean sinkage due to the loss of buoyancy, 
and second, determine the change of trim caused. 

Quantity of Water That Will Flow into a Ship Through a Hole 
in Her Side. 

Let H = distance center of the hole is below the water line in feet 
A = area of hole in square feet 
g = acceleration due to gravity (32.16) 
V — rate of flow i n feet per second 

Then V = V2 g H - S\/H approximately 
The volumejn cubic feet of water passing through the hole per sec- 
ond = 8 VH X A 

Example. A hole having an area of 2 sq. ft., 4 ft. below the water line was made 
in the side of a ship. What would be the approximate tons of water that would 
flow into her per minute? 

Cubic feet per second = 8 \/H X A - 8 \/l X 2 - 32. 

Cubic feet per minute - 32 X 60 = 1920. 



1920 
Tons per minute = "35"" 



54.85 tons. 



Calculating the Trim by the Trim Line Method when a Compart- 
ment is Flooded.* — Assume a box-shaped vessel 210 ft. long, 30 ft. 
beam, and 20 ft. deep, drawing 10 ft. forward and aft. Suppose 
she is in collision and a compartment at the after end is flooded 
Find the draft. (See Fig. 29.) 



B 


► 






c 


W 






'Sz 




S< 




A 









Figure 29 
* From Ship Calculations and Cons., G. Nicol. 



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196 SHIP CALCULATIONS 

Using the trim line method, first obtain the trim line at 10 ft. 
draft. W L is the level water line, W2L2 and W^L A those when 
at 2 ft. and 4 ft. by the stern. 

Assuming the vessel to be floating in salt water, her displacement 

210 X 30 X 10 
is — = 1800 tons, and in passing from the W L to 

W%Li y the wedge of displacement LSI* moves to the position 
W S W t . As S L is half the vessel's length, and L L 2 one foot, the 

volume of the wedge is = 1575 cu. ft., and in moving 

aft its center of gravity travels a horizontal distance g x g 2 or 
105X2: + 105X2 _ 140ft . 

The corresponding movement of the vessel's center of buoyancy 
is from B to B t) then BBt^GM XtanS 

i^Xl40 
. n wXa 35 A1W 1575 

tan v = — 



W X G M 1800 X 140 1800 X 35 
an A » » 1575 X 140 

aBdBBt 'mi x35 =s3 - 5ft - 

That is the horizontal travel of the center of buoyancy with the 
vessel trimming 2 ft. by the stern is 3.5 ft. With the vessel 4 ft. by 
the stern, the horizontal travel is double 3.5 ft. or 7 ft. 

From the above, a trim line can be drawn for the initial draft. 
Trim lines corresponding to other displacements can be obtained 
in the same manner. Fig. 30 is the complete diagram for the vessel 
and shows cross curves with a range of from 7 ft. 6 ins. to 15 ft. draft. 

Next begin with the calculation for the bilging. 

10 X 10 X 30 
Weight of water in bilged compartment = — = 85.71 

uu 

tons; 

Parallel sinkage assuming water situated amidships and compart- 

85.71 X35 X12 .. 
ment open to sea = t^t ^ — = 6 ins. 

Horizontal travel aft of vessel's center of gravity, assuming the 

* Center of gravity of a wedge is H from the apex. 

f The length of the water line, instead of being 210 ft., is now 200 ft., as the 
compartment flooded is 10 ft. long. 

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CALCULATIONS FOR TRIM 



197 



water at the increased draft to move into its true position and the 

ship's bottom to be intact: 

new draft of 10' 6" X 10' length X 30' beam ^ x 

w = ^z — 90 tons 

oo 

__ 210' — 10' (length of compartment) inA . 

a — gy sB 1UU It. 

W = original displacement of 1800 tons + 90 tons = 1890 tons. 



w 



1890 




Figure 30 



Referring to Fig. 30 the trim line corresponding to a level line at 
10 ft. 6 ins. can be drawn, and by measuring 4.76 ft. along this line 
from A B, and erecting a perpendicular and scaling it, its length 
2 ft. 10Ji ins. is the trim by the stern. The drafts will be 

Forward = 10' 0' + parallel sinkage of 6' - y 2 (2' 10M") = 

'9' oy 8 " 

Aft - 10' 0' + parallel sinkage of 6" + % (2' 10^") - 

11' UK' 
v In the second approximation, start with the vessel in the above 



8 



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198 SHIP CALCULATIONS 

trim. The weight of the water in the bilged compartment will be 
11.86 X 10 X 30 



35 



= 101.66 tons. 



D „ , . ! 101.66 tons X 35 cu. ft. X 12 ins. a% , . 

Parallel smkage = 210 ft. X 30 ft = ^ ins ' 

nearly. 

Taking the center of gravity of the water line at. the middle of 
the length of the compartment, then the travel of the vessel's center 

wXa 101.66 X^ 
of gravity due to admission of water = w = 1800 . 101 66 = 

5.35 ft. aft. By laying this off on the trim diagram, on the water 

line, and scaling up to the trim line, the trim will be found to be 

3 ft. 2J£ ins. by the stern. 

Dividing this equally forward and aft, and adding 6% ins. as the 

parallel sinkage, the drafts become 

Forward 10' 0* + 6M' - 1' W% = 8' 11^" 
Aft . 10' 0* + 6M" + 1' 7%" = 12' 2%* 

Calculating. the Trim by Mean Sinkage when a Compartment is 
Flooded.* — A rectangular lighter 100 ft. long, 40 ft. beam, 10 ft. deep, 
floating in salt water at 3 ft. draft, has a collision bulkhead 6 ft. 
from the forward end. If the compartment forward of this bulk- 
head is flooded, what would be the trim in the damaged position? 
(See Fig. 31.); 

(1) Determine the amount of mean sinkage due to the loss of 
buoyancy. 

(2) Determine the change of trim caused. 

(1) The lighter, due to the damage, loses an amount of buoyancy 
represented by the shaded part G B, and if it is assumed the lighter 
sinks down parallel, she will settle down at a water line w I such that 
volume wG = volume G B. This will determine the distance x 
between w I and W L. (?L = 6 ft., w H = 94 ft. 

For the volume w G = w H X 40 f t. X x 
For the volume G B = G L X 40 ft. X 3 ft. 
G L X 40 X 3 18,. 01/ . 
a; = -^tfxl0- = 94 ftor2 ^ mS - 

(2) Change of trim. 

* From Theo. Naval Architecture, L. T. Attwood. 

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WHEN COMPARTMENT IS FLOODED 



199 



Volume of displacement in cubic feet = 100 X 40 X 3 
100X40X3 2400 
35 7 



Displacement 



= 342 tons, and this 



weight acts through G, the center of gravity, which is 50 ft. from 
either end. 



UL- 


A 


£ 1 






W 


A 








L 


V 


ef 




<9 

a 


//// 





Figure 31 

But there has been lost the buoyancy due to the part forward of 
the bulkhead E F, and the center of buoyancy has now shifted back 
to B 1 such that the distance of B l from the after end is 47 ft. 

Therefore W, the weight of the lighter, acts down through G 1 

and W the upward force of buoyancy acting through B\ forming a 

240ft ' 720ft 

couple of W X 3 ft. = =y^ X 3 = -~ = 1028 foot-tons, tending 

to trim the lighter. 

To find the amount of this trim, the moment to change trim one 
inch must be found by the formula. 

Now G M equals B M nearly, therefore the moment to change 



trim one inch = 



342 



XBM = ^XBM. 



100 X 12 ~ 7 

Let / = the moment of inertia of the intact water plane about 
a transverse axis through its center of gravity. 

V = volume of displacement in cubic feet = 12000 



'-i^ 94 



BM = ^ = 



Moment to alter trim one inch = 
nearly. 



X 40) X 94* 

40 X 94 s 
12 X 12000 

2 X 40 X 94* 



7 X 12 X 12000 



= 66 foot-tons 



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200 



SHIP CALCULATIONS 



7200 

Therefore change of trim =» -^- — -^- 

do oo 

The new water line W 1 & will pass through the center of gravity 

of the water line wl at K, and the change of trim aft and forward 

must be in the ratio 47:53, 

47 

100 

53 



Decrease of draft aft 



15J^ ins. 



X 15^ - 7M ins. 



Increase of draft forward « 



100 



X 15J^ - SH ins. 



New draft aft « 3 ft. + 2H ins. [from (1)] - 7% ins. = 2 ft. 7 ins. 
New draft forward = 3 ft. + 2\i ins. [from (1)] + 8M ins. = 
3 ft. 10H ins. 



CENTER OF GRAVITY. 

Coincident with the calculations of the displacement and cen- 
ters of buoyancy, are made calculations of the fore and aft, and ver- 
tical positions of the common center of gravity of the hull, ma- 
chinery and cargo. The fore and aft position of the center of 
gravity of all the weights must come over the fore and aft position 
of the center of buoyancy. If on the first estimate it does not, 
then the weights must be shifted until it does. 

On a profile of the vessel draw a vertical line midway between 
the forward and aft perpendiculars. Also draw a base line 
parallel to the water line, for getting the vertical distance of the 
center of gravity. Except when the keel is given a drag, the base 
line is taken as the molded line of the frames at the keel. 

To find the fore and aft position of the center of gravity of the 
hull, lay off a table as follows: 



Items 


Weights 


Dist. Cent, of Grav. 
from Amidships 


Moments 


Aft 


Forward 


Aft 


Forward 


Shell plating 

Bulkheads 

Deck plating 

&c. 














w 


M aft 


M forward 



y Google 



CENTER OF GRAVITY 



201 



Assuming the moments aft to be greater than those forward then 

moments aft — moments forward ,. , . - .. . - A 
1~ n — distance center of gravity is aft 

of amidships. 

To find vertical position of center of gravity of the hull, lay off a 

table thus: 



Items 


Weight 


Dist. Cent, 
of Grav. 
from Base 


Moment 


Shell plating 








Rillkhparjs , 




Deck plating 




Web frames 




&c. 




• 


w 


M 



The sum of the moments divided by the sum of the weights gives 
the distance the center of gravity is above the base. 

To find fore and aft position of the center of gravity of a ship, 
rule a table as below: 



Items 


Weights 


Dist. Cent, of Grav. 
from Amidships 


Moments 




Aft 


f orward 


Aft 


Forward 


Hull 












Boilers 




Engines 




Cargo in forward hold. . . 

Cargo in aft hold 

Stores forward 




Stores aft 




Rankers 




Water ballast forward. . . 

Water ballast aft 

Fresh water 




&c. 




W 


M aft 


Mfor'd 



y Google 



202 



-SHIP CALCULATIONS 



Assuming the moments aft to be greater than those forward then 

moments aft — moments forward ,. A ' 

~p- = distarice of center of gravity 

aft of midships. 

To find vertical position of the center of gravity of a ship, lay off 

the following table: 



Item 


Weight 


Dist. Cent, of 

Grav. Above 

Base 


Moment 


Hull 


" 






Boilers 




Engines . . 




Cargo in forward hold 




Cargo in aft hold 




&c. 






w 


M 



The sum of the moments M divided by the sum of the weights 
W will give the distance the center of gravity is above the base. 

Care must be exercised in locating the engines, boilers, cargo, 
tanks and other weights in a ship. If they are placed too high, 
the ship will be unstable and if too low she will be very uncom- 
fortable in a seaway, owing to too quick a return to the vertical 
position. 

The table below gives the heights of the center of gravity of 
ordinary passenger and freight steamers, and of freight steamers. 









Center of Gravity Above Base 




Length 


Breadth 


Depth 
Molded 






Metacenter 






Above Base 








Machinery 


Equipped Vessel 




150' 


30' 


15' 


10' 6' 


IV 6* 


25' 0* 


200' 


35' 


20' 


11' 0" 


14' 6' 


23' 0' 


250' 


40' 


22' 


12' 0' 


15' 0* 


18' 0' 


300' 


45' 


24' 


12' 6' 


17' 6' 


19' 0' 


350' 


48' 


28' 


13' 0* 


19' 6' 


20' 6' 


400' 


50' 


32' 


16' 0* 


22' 0* 


22' 0' 


450' 


54' 


36' 


18' 0' 


23' 0' 


23' 0' 



Approximately the vertical height of the center of gravity of a 
ship is .50 to .70 of the molded depth. 

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EFFECT OF MOVING WEIGHTS 203 

Effect of moving weights on the center of gravity of a vessel. 
(1) Suppose the Weight Was Raised. — The distance the center 
of gravity of the vessel was raised would be found by multiplying 
the weight moved by the distance it was moved and dividing the 
result by the total weight or displacement. 

Example. A weight of 30 tons was raised from the hold and placed on the deck 
of a steamer at a distance of 20 ft. from its original position. The steamer had a 
displacement of 1000 tons. Find the distance the center of gravity was raised. 

weight X distance _ 30 X 20 _ 
displacement = 1000 "" 6 ft * 

(2) The Weight Was Removed. — In this case multiply the weight 
by its distance from the center of gravity of the ship, and divide 
the product by the displacement after the weight was removed. 

Example. A weight of 30 tons 10 ft. below the center of gravity of a ship of 

1000 tons displacement was removed. How much was the center of gravity raised? 

weight X distance 30 X 10 



displacement — weight 1000 — 30 



.3 ft. 



(3) Adding a Weight. — Multiply the new weight by its distance 
from the center of gravity of the vessel and divide by the new 
displacement. 

Example. A weight of 30 tons was placed on board of a steamer with an original 
displacement of 1000 tons 10 ft. below her center of gravity. Find the distance 
the center of gravity was lowered. 

weight X distance _ 30 X 10 _ 300 _ 
displacement + weight ~ 1000 + 30 ~ 1030 "" - 28ft ' 

(4) Moving a Weight Athwartships. — Multiply the weight by 
the distance moved and divide by the displacement. 

Example. A weight of 20 tons at the center of the upper deck was moved 10 ft. 
to starboard. The steamer had a displacement of 1000 tons. Find the distance 
her center of gravity was moved. 

weight X distance 20 X 10 , 

displacement = ""lOOCr = ' 2 ft ' to larboard. 

(5) Afoving a Weight in Two Directions. — The new positions 
of the center of gravity can be found by using formulae (2) and (4). 

Example. In a vessel of 4000 tons displacement, 100 tons of coal were shifted 
so its center of gravity moved 18 ft. transversely and 4 ft. 6 ins. vertically. Find 
the new position of the center of gravity. 

100X4.5 
By (2) the center of gravity will move vertically ^qqq — = . 11 ft. 

100 X 18 
By (4) the center of gravity will move horizontally — —£- — = 45 ft 

4000 
(Author not known) 

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204 SHIP CALCULATIONS 

In this case, however, the angle of heel is usually calculated instead of the dis- 
tance the center of gravity moves. Thus in the above example assuming the 

20 X 10 20 X 10 

steamer had a Q M of 2 ft. the angle of heel would be « 

1000 X G M 1000 X 2 
= .10, consulting the table of natural sines, the angle is found to be 5 degs. 75 mins. 

To Find the Center of Gravity of a Vessel by Moving Weights.* — 
Even if the position of the transverse metacenter is known, it is 
of itself of no value in predicting a vessel's initial stability as the 
center of gravity of the entire vessel (hull, machinery, and cargo) 
must be known. The center of gravity can be calculated as out- 
lined above, or it can be obtained by the inclining experiment as 
described below. 

A perfectly calm day should be selected, all the crew ordered 
off the vessel, all movable weights made fast, and the vessel trimmed 
so she is perfectly upright. A plumb line is hung down one of the 
hatches (sometimes two at two different hatches), usually as near 
amidships as possible. At the end of the plumb line a horizontal 
batten is placed on which can be marked the deviation of the plumb 
line when the vessel is inclined. 

A weight 1 is shifted from port to starboard on the top of weight 
3, through a distance of d feet, and the deviation of the plumb line 
noted. 

Weight 2 is shifted from port to starboard on top of weight 4 
and the deviation of the plumb line noted. 

The weights 1 and 2 are then replaced in their original position, 
the vessel returning to the upright position again. 

Weight 3 is moved from starboard to port on top of 1 and the 
deviation of the plumb line noted, and similarly 4 is moved on top 
of 2. Then the weights are returned to their original position. 

If to = weight moved in tons 

W — displacement of vessel in tons 

a = deviation of plumb line along the batten in ins. 

I = length of plumb line in ins. • 

d «- distance weight is moved in ft. 

GM = distance between the center of gravity and the trans- 
verse metacenter in ft. 

wXdwXdXl 



Then G M 



TTxf WXa 



* From Theo. Naval Architecture, E. L. Attwood. 

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FREEBOARD 



205 



Example. A steamer has a displacement of 5372 tons, and draws 16 ft. ins. 
forward and 22 ft. 10 ins. aft. Weight used for inclining 50 tons, which was moved 
36 ft. Length of plumb line 15 ft. Two plumb lines were used. 





Deviation of Plumb line 
in 15 ft. 




Forward 
(Inches) 


Aft 
(Inches) 




5H 
iom 

10H 


5H 




10% 








5H 




10J4 







Thus the mean deviation in 15 ft. for a shift of 25 tons through 36 ft. is 10 A 
ins. - 10.312 ins. 

w X d X I 25 X 36 X 15 X 12 * 



Then OM — w x q - 53?2 x 1Q ^ 

1 Multiply by 12 to reduce to ins. as the deviations are in ins. 



■ 2.92 ft. 



FREEBOARD * 

The full scantling vessel is taken as of sufficient strength, and is the 
standard by which strength is gaged. Vessels which are less strong 
are required to have more freeboard. For the full scantling vessel 
the freeboard is determined solely by the desirable reserve of buoy- 
ancy. 

The percentage of the total volume which is given on Plate I 
as a reserve buoyancy for a vessel of given type and dimensions 
will be the amount of volume that must be left out of the water. 
If a line be drawn upon this displacement curve at a draft sufficient 
to cut off the given percentage of total volume, the height of side 
above this draft will be the freeboard required. 

In order to simplify and reduce the work that would be involved 
by the above mode of determining the maximum allowable draft 
and the consequent freeboard that corresponds to a given percentage 
of reserve buoyancy, tables were evolved which, for a ship that con- 
formed to a so-called "standard" ship, gave directly the percentages 
of reserve of buoyancy and freeboards necessary for different sizes 
and types of vessel. The curves of Plates 2 and 3 are plotted from 
these tables. 

The standard ship was considered to be a flush deck ship 
with a certain sheer which was termed standard or normal sheer, 
with a certain proportion of length to depth and with a standard 

* Published in Int. Marine Engineering by Prof. H. A. Everett, revised by him. 
April, 1917. 



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206 SHIP CALCULATIONS 

roundup of deck beams, and for this vessel the curves read directly. 
Deck erections contribute to safety and are taken account of as a 
corrective term, as are also other variations from the standard ship. 
In practice the freeboard is actually assigned after the ship is built 
and usually by one of the classification societies' agents, but its pre- 
liminary determination is an important and necessary item in the 
design of any vessel, as the draft plus the freeboard gives the depth. 

The complete tables as issued by the British Board of Trade 
take up a variety of modifications and corrections which are in- 
volved by vessels differing from the arbitrarily assumed standard. 
The following work is based upon the rules directly, although the 
presentation and the wording are modified. The curves given on 
Plates 1-4 are a graphical representation of corresponding tables 
in the rules. Spar deck steamers and sailing vessels are not in- 
cluded as these classes are not numerous in present-day designs. 

The limitations of loading as laid down by the above act (for 
complete text see publication issued by Marine Department of the 
British Board of Trade, entitled Instructions to Surveyors, Load 
Line) are represented by a disk and number of horizontal lines 
which are cut and painted on the side of the ship amidships as 
shown in Fig. 32. The upper edge of each line is the point of meas- 
urement. 

The word "freeboard," legally, denotes the height of the side 
of the ship above the water line, measured at the middle of her 
length along the load water line. It is measured from the top of 
the deck at the side. The reserve of buoyancy necessary for flush 
deck steamers of full scantling and awning deckers are given by 
the curves on Plate 1 and these curves hold for any and every vessel 
regardless of proportions. For the standard vessel of these classes 
and within the dimensions given the freeboards required may be 
read directly from Plates 2 and 3. 

For awning deck vessels the freeboards are determined more 
by considerations of structural strength than by reserve of buoy- 
ancy, and indicate the dej)th of loading beyond which it is probable 
that first class vessels of this type would be unduly stressed when at 
sea. Therefore the freeboards and percentages of reserve buoyancy 
are in excess of what would be required for full scantling vessels. 
They are measured to the deck below the shelter or awning deck. 
The freeboards given in the curves are for flush deck vessels in all 
cases, and for the standard ship — a ship which has no deck erections, 
has a proportion of length to depth of 12, has a roundup of deck 

Digitized by vjOOQ 1C 



























«0 




















































V 

X 

N 


























> 


























* 
** 


























•0 

<0 


























•0 


























•0 














c\ 












•0 ^ 








A 






C; 












<* 


















^ 








<0 
























' 


























- 


si 






















\ 
















^ 




« 




\ 




1 


<0 




■0 


*> 












58 


!? 


^ 



JC/0Ju*c/ &£JJO /b/7& &/IS?&*£/ 



207 



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zed by G00gk 



208 SHIP CALCULATIONS 

beams of \i inch per foot of beam, and has a mean sheer in accord- 
ance with that derived from the curves shown on Plate 4. 

The data required for determining the freeboard by the curves 
are: 

1. Type of ship 

2. Dimensions 

3. Mean sheer 

4. Round of beam 

5. Description of deck (where statutory deck line is placed) 

6. Coefficient of fineness 

The type of ship must be agreed upon in order to ascertain which 
table will meet the case and whether modifications are necessary. 

The length for freeboard is measured at the load line from the 
fore side of the stem to the after side of the sternpost in sailing 
ships, and the after post in steamers. 

The breadth for freeboard is the extreme breadth measured to 
the outside of plank or plating as given on the certificate of the 
ship's registry. 

The depth for freeboard is the depth of hold as given on the cer- 
tificate of the ship's registry. This is the depth for determining 
the coefficient of fineness. (Upper deck beam at side in flush deck 
vessels, main deck beam at side in spar and awning deck vessels 
to top of ceiling or sheathing on double bottom.) 

Coefficient of Fineness. — This in one-, two-, and three-deck 
vessels is found by dividing 100 times the gross registered tonnage 
of the vessel below the upper deck by the product of the length, 
breadth, and depth of hold. In shelter deck vessels the registered 
depth and tonnage are taken to the deck below the shelter deck. 

Molded Depth. — The molded depth of an iron or steel vessel, 
as used in the curves, is the perpendicular depth taken from the 
top of the upper deck beam at side, at the middle of the length of 
the vessel to the top of the keel and the bottom of the frame at the 
middle line. This is the depth for the proportion of length to depth. 

Freeboard.' — The molded depth, taken as above described, is 
that used in the curves for ascertaining the amount of reserve 
buoyancy and corresponding freeboard in vessels having a wood 
deck, and the freeboard is measured from the top of the wood deck 
at side, at the middle of the length of the vessel. Where wood 
decks are not fitted on the upper decks, the freeboard should be re- 
duced by the thickness of the wood deck or the percentage of it 

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210 SHIP CALCULATIONS 

corresponding to the percentage of the length covered by substantial 
deck erections if they cover less than 70%. 

The following example will illustrate the application oj the curves 
when dealing with a standard vessel. Jn a steamer 357 ft. long, 
extreme beam 40 ft., depth of hold 26 ft., registered tonnage under 
deck 2,980 tons, molded depth 29.8 ft., under deck capacity 298,000 
cu. ft., which divide by 382,000 — that is, the product of the length, 
breadth, and depth of hold — the quotient is .78 or the coefficient 
of fineness. 

Referring to Plate 2 at 29.75 ft. molded depth and coefficient 
.78, the winter freeboard given for a standard steam vessel (with- 
out erections and length 12 times the molded depth) is 7 ft. 7 ins., 
which corresponds to a reserve buoyancy of 32% of the total bulk. 

Vessels rarely conform to the proportions assumed for the stand- 
ard, and the correct determination of freeboard for the actual 
vessel becomes a matter of properly applying the corrections to 
allow for the departure from the standard. The variations most 
commonly met with are the sheer, deck erection, and proportions 
of length to depth. The corrections for each of these items must be 
made and in the order given, as the correction for erections is based 
upon the difference between the freeboard for full scantling vessels 
corrected for sheer and the freeboard for awning deck vessels (un- 
corrected). 

Sheer. — The tables are framed for vessels having a mean sheer 
of deck measured at the side, as shown in the sheer diagram of Plate 4. 

In flush dock vessels and in vessels with erections on deck, 
when the sheer of deck is greater or less than the above, and is of 
gradual character, divide the difference in inches between it and 
the mean sheer provided for by 4, and the result in inches is the 
amount by which the freeboard amidships should be diminished or 
increased, according as the sheer is greater or less. 

In all cases the rise in sheer forward and aft is measured with 
reference to the deck at the middle of the length, and where the 
lowest point of the sheer is abaft the middle of the length, one-half 
of the difference between the sheer amidships and the lowest point 
should be added to the freeboard specified in the tables for flush 
deck vessels and for vessels having short poops and forecastles only. 

Erections on Deck. — For steam vessels with topgallant fore- 
castles having long poops, or raised quarter decks connected with 
bridge' houses, covering in the engine and boiler openings, the 
latter being entered from the top and having an efficiently con- 
Digitized by vjiOOQ 1C 







211 



Digiti 



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212 



SHIP CALCULATIONS 



structed iron bulkhead at the fore end, a deduction may be made 
from the freeboard given in the curves according to Curve A, Plate 4. 

When the erections on a vessel consist of a topgallant forecastle, 
a short poop having an # efficient bulkhead and bridge house discon- 
nected, the latter in steamers covering the engine and boiler open- 
ings, and being efficiently inclosed with an iron bulkhead at each 
end, a deduction may be made from the freeboard given in the 
curves, according to Curve B, Plate 4. 

When the erections consist of a topgallant forecastle and bridge 
house only, the latter in steamers covering the engine and boiler 
openings, and being efficiently inclosed with an iron bulkhead at 
each end, a deduction may be made from the freeboard given in 
the curves according to Curve C, Plate 4. 

When the erections on a steamer consist of a short poop or raised 
quarter deck of a height from 3 ft. to 6 ft. for lengths of ship of 250 ft. 
to 400 ft., and topgallant forecastle only, the former being inclosed 
at the fore end with an efficient bulkhead, and when the engine and 
boiler openings are entirely covered, a deduction may be made 
from the freeboard given in the curves according to Curve D, 
Plate 4. 

Vessels of Extreme Proportions. — For vessels whose length is 
greater or less than 12 times the molded depth for which the curves 
are framed, the freeboard should be increased or diminished as speci- 
fied in the following table: 

Table 1 



Correction in freeboard. for a 


Molded Depth 


Length 


Change of 10 ft. 


in Length 


Ft. 


Ft. 


1.2 




20 -23 


240-276 


1.3 




23^-25^ 


28S-306 


1.4 




26 -28 


312-336 


1.5 




2S 1 A-30*A 


342-366 


1.6 




31 -33 


372-396 


1.7 




33^-50 


402-600 



For shelter deck vessels the correction is Y* that specified in the above table. 



Thus if the vessel in the above example were 367 ft. long, the 
winter freeboard would be 7 ft. 7 ins. plus 1.5 ins., or 7 ft. 8.5 ins. 
For steam vessels with normal inclosed deck erections as on Plate 4 



jvJ^v^ 



ROUND OF BEAM 213 

(Curves A and B), extending over A or more of the length of the 
vessel, the correction for length should be % that specified in the 
table. 

Round of Beam. — In calculating the reserve of buoyancy an 
allowance has been made for the roundup of % inch for every foot 
of the length of the midship beam. When the total roundup of the 
beam in flush decked vessels is greater or less than given by this rule, 
divide the difference in inches by 2 and diminish or increase the free- 
board by this amount. For vessels with erections on deck the 
amount of the allowance should depend on the extent of the main 
deck uncovered. 

Breadth and Depth. — It has been assumed that the relation 
between the breadth and depth is reasonable, and for vessels of less 
relative breadth the freeboard should be increased to provide a suffi- 
cient range of stability. The following illustrates the application 
of the curves when dealing with a vessel not conforming to the 
standard type: 

A vessel 234 ft. long, 29 ft. beam has a molded depth of 17 ft., 
the coefficient of fineness being .72. Suppose she has a poop and 
bridge house of a total length of 121 ft. and a forecastle of 20 ft., 
and the sheer forward measured at the side 4 ft. 6 ins., and aft 
2 ft. 1 in. 

Ft. Ins. 
Freeboard by Plate 2, if of standard proportions, without 

erections and with the normal amount of sheer 2 11 

The mean sheer by rule is 33.4 ins., or 6 ins. less than that 
in the vessel, and the reduction in freeboard is 6 ins. di- 
vided by 4 \ x /i 

Freeboard of vessel without erections and with 39 J^ ins. 

mean sheer 2 9M 

Freeboard by Plate 3 as awning deck 93^ 

Difference 2 

The combined length of the erections is \\\ or six-tenths of the 
length of the vessel, and the allowance for erections from Curve A, 
Plate 4, will be four-ten the of 24 ins. or 9}^ ins. Thus 

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214 



SHIP CALCULATIONS 



Deduct Ins. 

Amount deducted from freeboard for excess of sheer 1J^ 

Amount deducted from freeboard for erections 9 A 

Amount deducted if vessel be fitted with an uncovered 
iron main deck = A X Z l A 2 



The length being 30 ft. in excess of that for which the 
tables are framed, the addition to the freeboard for 
excess length is A of \% or 1.1 ins. or 



13 



1H 



That is \\ X A ins. is to be deducted from 2 ft. 11 ins. leaving a win- 
ter freeboard of 1 ft. \\ X A ins. Corresponding summer freeboard 
1 ft. 9 ins. 

Vessels loaded in fresh water may have less freeboard than that 
given in the several tables, according to the following scale: 



Table 2 





Reduction in Freeboard 


Molded Depth in Ft. 


Vessels Without 
Erections on Deck 


Shelter and Awning 
Deck Vessels 


19 and under 22 


4 

5 
6 


4^ 


22 and under 25 


5 


25 and under 28 


5M 


28 and under 31 


6 


31 and under 34 


VA 







The weight of a cubic foot of salt water is taken in the above table as 64 lb. and 
of fresh water 62.5 lb. 

In no case shall the deepest load line in salt water, whether in- 
dicating the summer or Indian summer line, be assigned at a higher 
position than the intersection of the top of the upper deck with the 
vessel's side at the lowest part of the deck. In the case of shelter 
deck vessels the deck next below the shelter deck is to be regarded 
as the upper deck. 

So far the question of freeboard determination has been con- 
sidered from the viewpoint of its determination for some existing 
ship whose characteristics are known. The most useful function 
of the work as presented here is to permit a solution for the depth 
of vessel under design. The accurate determination of freeboard 



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216 SHIP CALCULATIONS 

should properly be attempted only from the complete tables re- 
ferred to earlier, but from the information here presented, it is pos- 
sible readily to determine the freeboard and therefore depth for a 
proposed design which has progressed sufficiently to have its length, 
draft, block coefficient, and general arrangement selected. In gen- 
eral the coefficient of fineness is sufficiently close to the block co- 
efficient to accept the latter for entering the curves. 

In considering a vessel under design, the general procedure 
for determining the freeboard of a full scantling vessel should be 
as follows: 

1. Assume a molded depth which seems reasonable, enter the 
curves, and for this depth read off the freeboard for the proper co- 
efficient of fineness. 

2. Correct this freeboard for sheer and erections and add the 
corrected freeboard to the draft to determine a revised molded 
depth. Multiply it by 12 and the difference between this and the 
actual length gives the basis for determining the corrections for 
proportions. 

3. Determine the correction for proportions and the original 
freeboard corrected for these three elements (sheer, erections, and 
proportions), when added to the draft, should give a molded depth 
in agreement with that originally assumed. If it does not, repeat 
the solution, starting with a modified assumed depth. The first 
trial will rarely give agreement but the second or third should 
suffice. 

Shelter deck steamers now form such a large proportion 
of the tonnage afloat that they need to be treated as a special class, 
and the revised rules do so take cognizance of them. The freeboard 
of a shelter deck steamer must in no case be less than the freeboard 
which would be assigned to a complete awning deck steamer of the 
same dimensions. The shelter deck rules are framed for a vessel 
having a complete superstructure covering the full length of the 
vessel, the deck continuous and unbroken at the side, but having 
one or more openings along the middle line of the deck, such open- 
ings not to have permanent means of closing in the shape of hatch- 
ways fitted with coamings, cleats, etc. The deck below the shelter 
deck is called the upper deck and is the one to which freeboard is 
measured. 

For shelter deck vessels the steps for determination of freeboard 
are the same as in full scantling vessels, considering them as full 
scantling vessels with very long erections, and the freeboard is 

Digitized by UOOQ LC 



ASSIGNING FREEBOARDS 217 

measured to the deck below the shelter deck (upper deck). There 
is no correction for round up of deck beams for awning and shelter 
deck vessels. The order of procedure is: 

1. Assume a reasonable depth (molded) and read the freeboard 
from the curve for this abscissa on Plate 2. 

2. Correct this for sheer and use this corrected freeboard in esti- 
mating allowances for erections. 

3. Correct for erections. 

4. Use this newly corrected freeboard for determining the depth 
(molded) for proportions. Multiply it by 12 and correct for pro- 
portions. 

5. Add this final freeboard to the draft and get a depth which 
should agree with that first assumed. If it does not, repeat the 
solution. Two or three trials should suffice. 

In assigning freeboards to shelter deck vessels, the following 
rules should be observed: 

1. In making the sheer correction in accordance with the para- 
graph on Sheer, the sheer is to be measured at the ends of the vessel 
and the freeboard corrected for sheer is to be used in estimating 
the allowance for erections. 

2. (a) If there is but one opening in the shelter deck the allow- 
ance for deck erections is to be determined from Curve A, Plate 4, 
provided that the effective length of the shelter deck is not less than 
six-tenths of the length of the vessel. 

(b) If there are two or more openings in the shelter deck the 
allowance for deck erections is to be determined from Curve B, 
Plate 4, provided that the effective length of the shelter deck, ex- 
cluding openings, is not less than six- tenths of the length of the 
vessel. 

3. The effective length of the shelter deck is to be calculated in 
the following manner, provided the openings in the shelter deck do 
not exceed half the vessel's breadth at the middle of the length of 
the opening. The length is taken as if each opening were an open 
well. The value of each part is assessed in accordance with the 
different regulations affecting poops, bridge houses, and forecastles, 
open or close^. The final allowance for erections will depend upon 
whether or not temporary but efficient means are provided for 
closing the openings in the shelter deck. 

(a) If efficient means as specified below are provided for tem- 
porarily closing the openings in the shelter deck, the effective length 
of the shelter deck is to be reckoned as the length computed as 

Digitized by VjiOOQ 1C 



218 SHIP CALCULATIONS 

prescribed above, plus half the difference between that length and 
the length of the vessel. 

(b) If efficient means for temporarily closing the openings are 
not provided, the effective length of the erections is to be computed 
by adding to the length computed as above, one-fourth, instead of 
one-half the difference between that length and the length of the 
vessel. 

(c) If the openings in the shelter deck are wider than the half- 
beam at that point, the addition to the assumed length of erec- 
tions is to be modified in proportion to the relation which the actual 
opening holds to the specified breadth and to a complete well. 

To illustrate the method of determining the depth for a new 
design, and also the application of the rules to the shelter deck type 
of vessel, note the following: A complete shelter deck vessel 490 ft. 
long, 58 ft. beam, 28 ft. draft, block coefficient .80, has one tonnage 
opening in the shelter deck. Assume for the first trial depth 

r^ or -T5- = 40 ft., approximately 

Ft. ' 
At 40 ft. depth and .80 coefficient of fineness the freeboard 

for a full scantling vessel is 11 ft. 8 ins. (Plate 2) 11 . 67 

The sheer forward is 9 ft. and aft 3 ft., so the mean sheer is 

9-1-3 

«T X 12 = 72 ins. The standard or normal mean sheer 
2i 

from Plate 4 is 60 ins., so that the excess sheer is 72 — 60 = 

12 

12 ins., and the sheer correction is -r — 3 ins. = .25 ft 25 

.4 

This is to be subtracted, as the sheer is greater than the nor- 
mal, then freeboard corrected for sheer is 11 .42 

Freeboard for awning deck (Plate 3) (uncorrected) 8.41 

Difference 3.01 

The correction for erections is 90% of this (Curve A, Plate 4), 
as the erections cover 95% of the vessel length, .9 X 3.01 = 2.71. 
The freeboard corrected for sheer and erections then becomes 
11.42 - 2.71 = 8.71 ft. This, with a draft of 28 ft., gives a molded 
depth of 8.71 + 28 = 36.71 ft. 

A standard ship of this depth would have a length 12 times as 
great or 36.71 X 12 « 440 ft. (approximately), which is 50 ft. 
shorter than the actual ship, so the freeboard must be increased 

Digitized by VJiOOQ 1C 



FREEBOARD OF SCANTLING VESSEL 216 

1 7 
to correct for proportions. From Table 1 this correction = -57- 
inch for every 10 ft. excess of length, and the correction in feet is 

¥ x B x S= o708x § = - 35ft - 

Therefore the freeboard corrected for sheer, erections and propor- 
tion becomes 8.71 + .35 = 9.06 ft., and the molded depth is 9.06 + 
28 = 37.06 ft. 

This depth does not agree with that first assumed, so a second 
solution will be made using the depth just found as a trial depth. 
Assume for the second solution a trial depth of 37 ft. • 

Freeboard of full scantling vessel 10 . 50 

Less sheer correction .25 

10.25 
Freeboard for awning deck vessel 7 . 25 

Difference * 2.99 

Correction for erections .9 X 2.99 2.69 

Freeboard corrected for sheer and erections 7 .56 

Draft '. 28. 

Depth of ship at 28 ft. draft 35.56 

Corresponding length of standard ship 427. 

Length of actual ship 490. 

Difference 63. 

Correction for proportions (.0708 X 63) 43 

Final corrected freeboard 7.56 + .43 7.99 

Depth at 28 ft. draft = 28 + 7.09 35.99 

Repeating this process for a third trial depth of 35 ft., a re- 
sulting depth of 35.31 ft. and freeboard of 7.31 ft. is obtained. 



Table 3 

Allowable reduction from winter freeboard for summer free- 
board. Double these reductions allowed for the Indian Summer line 
and 2 ins. more required for the Winter North Atlantic line if of 330 
ft. length or less. 



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220 



SHIP CALCULATIONS 



Molded Depth 


Reduction 


Molded Depth 


Reduction 


Ft. 


Ins. 


Ft. 


' Ins. 


16.5 to 19 


2 


34 to 35.5 


6 


19 " 22 


*A 


36 " 37.5 


VA 


22.5 " 24.5 


3 


38 " 39.5 


7 


25 " 26.5 


% *A 


40 " 41.5 


m 


27 " 28.5 


4 


42 " 43.5 


8 


29 " 30 


*A 


44 " 45.5 


SH 


30.5 " 32 


5 


46 " 47.5 


9 


32.5 " 33.5 


VA 


48 " 50 


9>i 



Miscellaneous Notes 

In the United States there are no standard requirements although 
the American Bureau of Shipping has made suggestions as to the 
loading as follows: "No vessel is to be loaded so that the freeboard 
(measured at the lowest point of sheer) from the main deck . 
stringer plate to the water edge shall be less than is indicated in 
the following table: 



Depth of Hold from Top of Ceiling to Under 
Side of Main Deck Beam 


Freeboard at Lowest Point 

of Sheer for Each Foot 

Depth of Hold 


8 ft 


W 

2 

2Ji 

2% 
3 

za 

ZA 


ins. 


10 " 


it 


12 " 


n 


14 " 


a 


16 " 


a 


18 " 


tt 


20 " 


<t 


22 " 


it 


24 " 


a 


26 " 


u 


28 " 


a 


30 " 


u 







"It is suggested by the Rules Committee that the minimum free- 
board for hurricane deck vessels should not be less than A or for 
raised quarter deck vessels % of that indicated in the table. 

"The depth of hold for regulating freeboard to be measured to 
and the freeboard from, the second deck of hurricane deck vessels. 

"The depth of hold for regulating freeboard to be measured to 



y Google 



MARKING FOR STEAMERS 



221 



and the freeboard from, the main deck of vessels having a raised 
quarter deck." 

In Great Britain a committee was appointed by the Board of 
Trade in 1883, to formulate rules for the assigning of freeboard to 
vessels. These rules were revised in 1906, and with slight altera- 
tions remain in force today. Although Lloyd's assign freeboard to ves- 
sels yet perhaps the final authority or rather the authority Lloyd's 
follows are the regulations of the British Board of Trade. 

Freeboards are measured from a horizontal line squared out from 
the inner edge of a water way of assumed width (see Fig. 32). This 
horizontal line is called the statutory deck line and the vertical 
distance between it and the deck at the side the statutory allowance 
which averages about % of the round of beam. 



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Figure 32. — Freeboard Markings. 



Digiti 



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222 SHIP CALCULATIONS 

The freeboard regulations consist essentially of a number of 
tables which give in feet and inches the freeboards of vessels of 
any depth, within certain limits, that is vessels having a certain 
ratio of depth to length. The tables only strictly apply to standard 
vessels but provision is made for adapting them to those of various 
types. (For calculations and the assumptions made see Freeboard 
Tables, Board of Trade, London.) 

Freeboard Markings. — Center of disk to be placed on both sides 
of vessel amidships, i.e. at the middle length of the load water line. 
The disks and lines must be permanently marked by center punch 
marks or cutting. L R indicates Lloyd's Register. If the free- 
board has been assigned by the Bureau Veritas the letters used are 
B V. FW = Fresh Water, I S = Indian Summer, S - Summer, 
W = Winter, W N A = Winter North Atlantic. 

POWERING VESSELS 

The following formulae apply to all power-driven craft except 
hydroplanes. The results obtained should be compared with those 
of actual ships as given in tables on pages 310-320. 

To Find the Approximate I. H. P. to Propel a Vessel at a Certain 
Speed. 
Let H = indicated horse power of the engine 
D = displacement in tons 
V = speed in knots 

K = coefficient for small launches = 100 to 150 
yachts moderately fine and fair 

speeds = 200 
merchant vessels of moderate size = 220 to 

250 
larger vessels = 250 to 300 
fast passenger boats = 220 to 280 
torpedo boats = 200 
cruisers and battleships = 200 to 250 

Thenff = g and 7=^-^7==- 

Example. It is proposed to build a freight steamer 280 ft. long, displacement 
3800 tons, speed 10 knots. Find the approximate indicated horse power for the 
engine. 

Assume £ = 220 

Then H = g X </» - 12 Xj^ggog , 1190 
K 220 



Digitized 



by Google 



EFFECTIVE HORSE POWER 223 

Also for estimating the i. h. p. the following formula can be 
used, but it does not apply favorably to fast vessels but is suitable 
for low and moderate speeds. (See also paragraph in "Marine En- « 
gines" on estimating horse power.) 
H = i. h. p. 
V = speed in knots 
S = wetted surface in square feet 
K — coefficient for short beamy ships = 6. 

merchant vessels of ordinary form = 5. 
fine ships = 4. 
KXSXV* 



Then H « 



100000 



Effective Horse Power (e. h. p.) at a given speed is the horse 

power required to overcome the various resistances to a vessel's 

progress at that speed. Calling these resistances R and the 

R X Sf 
speed in feet per minute S then the e. h. p. = Q >fflnn • The ratio 

of effective horse power to the indicated horse power, viz. . ' 

at any speed, is the propulsive coefficient at that speed. For modern 
vessels with fine lines a propulsive coefficient of 50% may be ex- 
pected. In cases with extremely fine forms and fast running engines, 
the percentage increases. 

Towing. — To find the horse power required at a given speed, as, 
for instance, when a tug is towing a barge. 

R = resistance to motion in lb. 

v = speed in feet per minute 

V — speed in knots per hour 

H = horse power 

T . „ RXv RXV , 
Then//s= 33000= ^2G- nearly 

Example. At a speed of 10 knots per hour (or 1013 ft. per minute) the tow rope 
strain on a tug towing a barge was 10770 lb. Find the horse power necessary to 
overcome the resistance of the barge Alone. Work done per minute in foot- 
pounds = R X v = 10770 lb. X 1013 ft. 

RXv 10770 X 1013 00/1 



H = 



33000 33000 



17 X 27 X 45 
A 158 ft. tug, engine 5^ L (see table of Excursion and 

Harbor Vessels), can tow three barges of 1800 tons deadweight each 

Digitized by VjOOQ 1C 



224 SHIP CALCULATIONS 

at a sea speed of about 7 knots per hour. A 90-ft. tug, engine 

— — — , for harbor service can easily handle two square-ended 

scows 90 ft. long by 30 ft. beam. In ocean towing, the barges 
should be several hundred feet apart, as they tow more satisfactorily 
in this way than close together. 

To Find the Number of Revolutions of the Engine to Drive a 
Vessel at a Certain Speed.* 

P = pitch of the propeller in feet 

S = required speed in knots 

R = revolutions per minute at required speed 

N = number of feet in a knot (6080) 

8 = per cent of slip of propeller expressed as a decimal. 

6080 X S 



Then R, revolutions of engine 
S the speed in knots = 



60 X P X (1 - s) 
60XPXflX(l-s) 



6080 

Example. The pitch of a propeller is 16 ft. How many revolutions must it 
make to drive a ship at a speed of 10 knots per hour, the slip of the propeller being 
estimated at 10%. 

From the above formula the revolutions 

r = 6080 XS 6080 X 10 ?ol/ 

60 X P X (1 - s) " 60 X 16 X (1 - .1) "" * 

To Find the Number of Revolutions per Minute at Which to Run 
the Engine to Give a Required Speed.* 

R = revolutions* per minute for a given speed 
S = given speed 
Ri — required revolutions 
Si = required speed 

Then A -^|* 

Example. If a vessel travels at the rate of 16 knots an hour when the engine 
is making 64 revolutions per minute, what should be the number of revolutions 
per minute to reduce the speed to 14 knots? The revolutions required are given by 

the formula Ri = — = — substituting the above values, then — =-s — ™ 66 revolu- 
a io 

tions per minute. 

Formula for Estimating the Speed of a Motor Boat 

M — speed in statute miles per hour 
L = length over all (feet) 
♦From Mariner's Handbook 



THRUST HORSE POWER 225 

' B = extreme beam (feet) 
P = brake horse power of engine 
C = constant =9.5 moderate speed type 
8.5 high speed type 

- cVlxp 

M £— 

Thrust horse power, see Horse Powers. 

Calculation of thrust, see Propellers. 

Resistance. — The total resistance of a vessel is made up of fric- 
tional resistance, eddy making, and wave forming. The eddy mak- 
ing is about one-tenth of the frictional and does not exceed 5% of 
the power required to drive a vessel. As to the wave forming, it 
has been found impossible to formulate a practical law. Experi- 
ments made by Mr. Froude in England showed that the frictional 
resistance at a 6-knot speed is about J£ of a pound per square foot 
of wetted surface for ordinary painted ship's bottoms, and that the 
total resistance varies about as the square of the speed. Using 
Froude's value for frictional resistance as % lb. per square foot at 
6 knots, then frictional resistance of a vessel = square feet of wet- 
ted surface X }i lb. per square foot X I ^ — I 

, . resistance X speed in feet per minute 
and horse power m ^ K 

The actual resistance of ship to progress through the water is 
the e. h. p. (effective horse power) required, which is perhaps J^ of 
the indicated horse power. Within the lower limits of power and 
speed only the frictional resistance need be considered. The fol- 
lowing applies in general from J£ to J£ full power. 

1. The indicated horse power varies as the square of the speed. 

2. Consumption of fuel varies as the square of the speed. 

Example. If a steamer burns 40 tons of coal per day at a speed of 20 knots per 

hour, how many would she burn at 21 knots? 

40 
The consumption per knot at 20 knots is — = 2 tons 

Then the consumption per knot at 20 knots : to the consumption at 
21 knots = square of the speed at 20 knots : is to square of speed 
at 21 knots. 

2 : x - 20* : 21* 

2 X21 » _ _ . . . 

x — — 2oT~ = 2 * 2 ton8 P 61 " * cnot 

or 21 knots V 2.2 tons = 46.2 tons per hour. 
(Author not known.) • 

Digitized by vjOOQIC 



226 SHIP CALCULATIONS 

3. Total fuel consumption for any distance varies as the square 
of the speed times the distance. 

At half-speed the frictional resistance will be only \i of the frac- 
tional resistance at full speed. Since the power required to propel 
a ship is proportional to the product of the frictional resistance and 
the speed, it follows that the power delivered by the propeller is 
proportional to the cube of the speed. Thus at half-speed the out- 
put from the propeller is only y% of the output at full speed. This 
relation is not exact but is nevertheless widely used in making ap- 
proximate calculations, for the power required increases at high 
speeds more rapidly than as the cube of the speed. 

Table of Approximate Values for the Frictional Resistance 

of Snips 



Displacement in Tons 


Frictional Resistance in Pounds 

Per Ton at a Reference 

Speed of 20 Knots 


500 


42 


1,000 


34 


2,000 


26 


4,000 


18- 


8,000 


12 


16,000 


9 


32,000 


7 







From the above table it will be noted that for a given speed the 
frictional resistance per ton gradually decreases with increasing size 
of ship and attains a low value in large ships. 

Example. Find the thrust horse power of a 4000-ton ship when at a speed of 
22 knots. 

From the table the frictional resistance at a speed of 20 knots is given as 18 lb. 
per ton. For a speed of 22 knots the frictional resistance is 



(!)' 



4000 X I =gj X 18 = 87120 lb. 

rvu ^ ^^ 87120 X 22 knots X 6080 ft. 

Then thrust horse power = eo min . X 33000 lb. 59 °° nearly ' 

The law of comparison, or Froude's law, states: "The resistances 
of similar ships are in the ratio of the cubes of their linear dimensions, 
when their speeds are in the ratio of the square root of their dimen- 
sions." The speeds which are connected by this relation are 
known as corresponding speeds. The law applies only to that re- 
sistance for which the dynamic conditions are similar irrespective 

Digitized by VjOOQ 1C 



LAUNCHING 



227 



of size. However, this is not the case so far as fractional resistance 
of a ship is concerned and the law does not apply to it. For this 
reason the results of experiments with models have to be corrected 
for friction when they are applied to the ship; (See Ship Forms, 
Res. and Screw Propulsion, by B. S. Baker.) 

Froude's Surface Friction Constants for Weli^Painted Ships 
in Sea Water* 



Length of 

Vessel in 

Feet 


Coefficient 
. of 
Friction 


Power 

According 

to which 

Friction 

Varies 


Length of 

Vessel in 

Feet 


Coefficient 

of 

Friction 


Power 

According 

to which 

Friction 

Varies 




/ 


n 


/ 


n 


100 
120 
140 
160 
180 
200 
250 
300 


.00923 
.00916 
.00911 
.00907 
.00904 
.00902 
.00897 
.00892 


1.825 
1.825 
1.825 
1.825 
1.825 
1.825 
1,825 
1.825 


350 
400 

450 
500 
550 
600 


.00889 
.00886 
.00883 
.00880 
.00877 
.00874 


1.825 
1.825 
1.825 
1.825 
1.825 
1.825 



Let / = coefficient of friction from the above table 
8 = wetted area in sq. ft. 
V = speed of vessel in knots per hour 
R — frictional resistance 
Then R =fSV n -/SF 1 * 
( 71826 » i g y X 1.825) 



LAUNCHING 

Care must be exercised in the building so that when a vessel is 
ready for launching there are no heavy weights on deck or high 
above the keel. For a vessel in the launching condition has a light 
draft, great freeboard, and a high center of gravity. An estimate 
can be made of the metacentric height and if this is not sufficient 
the ship should be ballasted to lower the center of gravity. A 
minimum height of transverse metacenter above the center of 
gravity, of one foot, should be provided in the launching condition. 

Vessels are launched either stern first or sideways, the latter 
being the practice on the Great Lakes (U. S.). Where there is a 
considerable rise and fall of the tide, the launching ways extend 

♦From Naval Architecture, C. H. Peabody. 



Digiti 



zed by G00gk 



228 SHIP CALCULATIONS 

usually to the level of the water at low tide, but in cases where the 

tidal rise is small it may be necessary to carry them further out. 

The ways for vessels to be launched stern first should be so 

located under the hull that they come under a longitudinal or a 

keelson. The breadth of the ways depends on the launching weight. 

To determine the breadth, 

Let W = launching weight in tons 

I = length of cradle or sliding ways, which is about .8 the 

length of the vessel 

b « breadth of each way 

area of sliding ways = 2 6 X I 

W 
Then the average pressure per square foot on the ways = — 

The area of the ways should be such that the pressure per square 

W 
foot is not more than 2.5 tons. Thus let 2.5 = 7 — hence the 

Zo X * 

breadth of each way = . . . . — ,J~ e — -rp. See Launching Data. 
5 X length of cradle & 

The declivity of the ways should be' from ^ of an in. to the 
foot in large vessels to % in small. The camber or longitudinal cur- 
vature is from 12 to 15 ins, in 500 ft. 

In launching there are two critical periods: first, when the center 
of gravity has passed over the ends of the ways, for there is then 
little support aft and the ship has a tendency to turn about the after 
end of the ways and so concentrate the weight at that point; and 
second, when the buoyancy aft is sufficient to lift the ship and cause 
her to turn about the fore end of the cradle, there is then a long 
length' of structure unsupported and a great pressure is exerted over 
a short length at the fore end of the cradle and the launching ways. 

Launching Calculations.* — Assuming that the vessel has no tip- 
ping moment but gradually lifts aft as she launches, when she is 
almost entirely in the water — say when the fore poppet is over the 
end of the standing ways — the force of buoyancy pressing upward 
will react at the fore poppet, causing a downward pressure on the 
ways, tending to spread out the standing ways, to break the fore 
poppets, or to crush in the bows of the vessel. 

For calculating this pressure, first find the declivity of the ship 
on the ways, and of the launching ways, and also the position of 
the upper fine of the standing ways from the keel of the ship. As- 
certain the depth of water expected on the day of the launching. 

* From A Class Book of Naval Architecture, W. J. Lovett. 

Digitized by VJiOOQ LC 



-*-• 



\ 




*F?J? 



229 



Digiti 



zed by G00gk 



230 SHIP CALCULATIONS 

Make a tracing of the ship to a small scale (see Fig. 33), and di- 
vide it into displacement ordinates. Calculate the area of each 
section up to the several water planes and draw curves of areas at 
each section. 

Arrange for different positions of the ship. Place the tracing 
on the first shift on the drawing (say 250 ft.) and find the volume 
of displacement of the ship in the water, and the position of the cen- 
ter of buoyancy from the after perpendicular. Do likewise for 300-, 
350- and 450-foot shifts, or the shifts could be 25 ft. apart, if desired, 
instead of 50. 

Estimate the longitudinal position of the center of gravity of the 
ship. (See Center of Gravity.) Set up to scale the moment of 
weight about the fore end of the sliding ways or fore poppet. This 
is obtained by multiplying the weight of the ship by the distance 
of the center of gravity from the fore end of the ways. Next find 
the moment of buoyancy about the fore end of the ways. This is 
obtained from the equation 

Moment of buoyancy about the fore end of ways = 
volume of displacement X center of buoyancy from fore end of ways 

35 
35 cubic feet of salt water = 2240 lb. = one ton. 

Do this for each shift. Set off to the same scale the various values 
found for the moment of weight and the moment of buoyancy, and 
where they cross each other the ship will commence to rise. 

Set up the displacement at each shift and draw a displacement 
curve. Find the displacement at the point where the ship com- 
mences to rise. The difference between the displacement of the 
ship in the water and the displacement when she begins to rise, 
gives the weight bearing on the fore poppet. Find the moment 
of the weight about the after end of the standing ways. Also find 
the moment of buoyancy about the after end of the standing ways 
for each shift. Draw curves as in Fig. 34. If the curve of moment 
of buoyancy cuts the curve of moment of weights about the after 
end of standing ways, there will be a tipping moment, but when they 
do not cut there is a lifting moment. The different shifts are ob- 
tained by shifting the center of gravity of the vessel so many feet 
aft. The moment of weight about the after end of the ways is 
calculated by multiplying the weight of the ship by the distance 
of the center of gravity from the end of the ways at the different 
shifts. Thus when the center of gravity is exactly over the end of 
the ways, and the displacement taken at say 6000 tons, there would 

Digitized by VjOOQ 1C 



MOMENT OF BUOYANCY 



231 







be no moment of weight about the after end, because 6000 multi- 
plied by the distance of the center of gravity from the after end 
of ways, which is 0, is 0. At the 50-foot shift the moment will be 
6000 X 50 = 300,000 foot-tons, etc. 

y\ 

111 

TO! 

//&#?&,*£/ 

rajs* 7 



The moment of buoyancy is calculated by multiplying the actual 
displacement at the different shifts by the distance of the center 
of buoyancy of the various displacements from the end of the 
ways. The Weight on the fore poppets is obtained by reading the 
displacement when the ship begins to rise, which in Fig. 34 is at x. 
The displacement is P. Subtract O P from the displacement at 
the launching draft and the difference will be the weight on the fore 
poppets. 

tipping moment 

weight of ♦ship 

The tipping lever diyided by the length of the ship should have a 
certain ratio. A ratio of 1/18 is quite safe, but if more than 1/11 
there is likely to be trouble. 

Releasing, Starting and Checking Devices. — The former often 
consists of two dog shores with their heads toward the bow of the 
vessel and caught under a piece fastened to the sliding way. The 
heads and the bearings for them should be covered with steel plates. 
The dog shores are knocked down by simultaneously dropping 
weights on them, the weights being suspended by a single rope which 
on being cut will cause both to drop at the same time. A vessel 
may also be released by sawing through the sliding ways that have 

Digitized by vjOOQ 1C 



Tipping lever = 



232 



SHIP CALCULATIONS 



been extended and fastened at the shore ends. Care must be taken 
that both planks are sawn at the same rate. 

Should the vessel refuse to start when released, a hydraulic ram 
or jack- may be brought to bear at the end of each launching way, 
and also against the stem. 

To check the vessel after she has left the ways, hawsers are 
made fast to the hull, which are fastened to heavy chains on shore 
that are laid in piles at intervals. To prevent snubbing by sudden 
stopping, hawsers may be carried beyond the bitts and lashed at 
intervals to another hawser on the deck, the lashings being torn 
away as the vessel continues to move, thus gradually bringing her 
to rest. In some instances a wooden shield is fixed at the stern, 
but care must be taken that the shield has not such an area that the 
vessel will be stopped on the ways when only partly waterborne. 
Launching velocities vary from 13.7 to 17 ft. per second, and the 
distance run at these velocities is about % of the length of the vessel. 

The above applies to end launching, that is, stern first, which 
is the usual practice. For side launching the ways 'are given a 
steeper incline, and instead of only two there are several. One of 
the advantages of side launching is that the vessel may be built 
on an even keel. 

Launching Data 



Paddle 
Wheel 
Steamer, 
190' X 
22' X 
9' 



Screw Steamer 



234' X 

33' X 

18' 



270' X 

34' X 

19' 



330' X 

43M' X 

30^' 



360' X36' 
X28' 



400' X42' 
X29H' 



Declivity of keel per ft 
Declivity of standing 

ways per ft 

Camber of standing ways 
Length of standing ways 
Length of sliding ways . 
Breadth of sliding ways. 
Area of sliding ways in 

square ft 

Total fall in length of 

standing ways 

Water on way ends .... 
Draft of ship forward . . . 

.Draft of ship aft 

Mean draft.. 

Displacement in tons. . 
Mean pressure per sq 

ft. on sliding ways in 

tons 



A* , 

IS to At 

8* 

195' 

160' 

1'3* 

375 

12' 0* 
2' 9" 
4'0* 
3' 10" 
3' 11* 
215 



.57 



AtoM 

l'Q* 
267' 
180' 
1'9* 

630 

ISM* 
2' 8" 
5' 9" 
9'0* 

V 4^* 

. 865 

1.37 



a to n 

1' 10* 
300' 
200' 
1'9* 

700 

15' 6* 
3' 7* 
5' 7* 
10' 8* 

8' m» 

1000 



1.40 



A toil 
I'll* 

348' 
240' 
l'lO* 

880 

21' 6* 

3' 9* 

6'6V^* 

9' 5 1 2 * 

8'0* 

1660 



1. 



l'O*^ 
367' 
284' 
1'9* 



994 

18' 9* 
6'0* 
11' 6* 
14' 0* 
12' 9* 
2500 



2.51 



Atott 
1'2* 
395' 
330' 
1'9* 

1155 

19' 7" 
4' 4* 
7/0* 
10' 10^* 

9'03£* 
2157 



Above table from Design and Construction of Ships, J. H. Biles. 

Digitized by VjOOQ 1C 



U. S. BATTLESHIP "ARIZONA" 



233 



U. S. Battleship "Arizona," 600. ft. water line, 97 ft. beam, launching 
weight exclusive of cradle and ways 12,800 tons, total weight on 
grease 13.350 tons, sliding ways and cradle 70 ins. wide, effective 
length 505 ft., initial pressure per square foot on the grease 2.27 
tons, maximum observed velocity 21 ft. per second, was afloat in 
about 42 seconds. 

Freight steamer "Chokyu Maru," 277 ft. 7 ins. O. A., 268 ft. between 
perpendiculars, beam molded 40 ft. 9 ins., depth molded 23 ft. 6 ins.; 
draft loaded 19 ft. 9% ins., designed displacement 4887 tons, dead- 
weight 3067 tons, engine 19 X 3 *^ X 52 , i. h. p. 1060, speed 11 
knots. 

Declivity of keel blocks 1/17 

Declivity of launching Ways 1/16 

Length of sliding ways 217 ft. 

Width of sliding ways 1 ft. 9 ins. 

Width of standing ways 2 ft. 

Center to center of sliding ways 14 ft. 6 ins. 

Average pressure on standing ways 1.35 tons 

Maximum pressure on fore poppet when the stern 

lifted 315 tons 

Height of water at the end of standing way 5 ft. 6 ins. 

Launching speed ' 16.2 ft. per min. 

Launching weight, including cradles 1033 tons 

Average draft when afloat 4 ft. 7}^ ins. 

Displacement when afloat 971 tons 

Center of gravity of the hull and cradles, .83 ft. aft amidships 



Declivity op Ways and I<aunching Velocity 



Length of 


Launching 


Declivity 


Declivity 


Vessel 


Weight 


of Ways 


of Keel 


in Feet 


in Tons 


per Foot 


per Foot 


200 


200 


H 


tt 


280 


1,000 


A 


H 


300 


2,200 


A 


A 


430 


4,000 


Yt 


460 


5,000 


X 


H 


500 


7,000 


A 


A 



Camber 
of Ways 



Launching 
Velocity 
Feet per 
Second 



none 
6 ins. in 300 ft. 
9 ins. in 400 ft. 



14 ins. in 560 ft. 



12 to 13 

15 to 17 

18 



16 



- 



SECTION V 
HULL CONSTRUCTION 

CLASSIFICATION SOCIETIES AND ORGANIZATIONS 
GOVERNING SHIPPING 

Merchant vessels are built and maintained under the rules pre- 
scribed by any of the following societies: Lloyd's Register, Amer- 
ican Bureau of Shipping, British Corporation, Bureau Veritas ; 
and Norske Veritas. By so doing the owner can get more favorable 
insurance rates than if his vessel had not been constructed and 
was not kept up to the requirements of one of the above societies. 
Motor boats, that is, small pleasure and commercial craft, are not 
built according to any rules, and are consequently not classed. 

Lloyd's Register of Shipping, founded in 1760, is the largest and 
oldest society. Its head office is in London, England, with branches 
all over the world. In the case of a new vessel intended for classi- 
fication, the plans are first submitted to be approved by the Com- 
mittee and the building proceeds under the supervision of a local 
surveyor. No steel is used which has not been produced at approved 
works and tested at the works by the surveyors. When com- 
pleted a character is assigned to the vessel by the Committee upon 
the surveyor's report. 

Vessels built according to Lloyd's Register and classed with 
the Society are required at intervals of four years to be given special 
surveys. These surveys are designated as Nos. 1, 2, and 3, and 
as long as the vessel maintains her structural strength she keeps 
her class. 

Lloyd's Register issues annually to its subscribers a register book 
containing particulars of all seagoing vessels of 100 tons and up- 
wards, including those to which classes have been assigned. The 
figure 1 after the character assigned to a vessel thus, 100 A 1, de- 
notes that her equipment is in good condition and in accordance with 
the rules of the Society. The star or cross before the figure denotes 
that the vessel was built under special survey. If the engines and 
boilers were built and installed according to the rules, then it is 

Digitized by \J\JU\?Lt 



SHIPPING 235 

registered thus in the book »J« L M C. The highest rating is 
-f 100 A 1 *%* L M C. 

Lloyd's, the headquarters of the British Underwriters (an organ- 
ization entirely separate from Lloyd's Register of Shipping), was 
incorporated by act of Parliament in 1871, for the carrying on of 
the business of marine insurance by members of the Society. It 
comprises about 600 underwriting members and about 200 non- 
underwriting members > besides some 500 annual subscribers. 
The underwriters pay a large entrance fee and an annual subscrip- 
tion, and to place their credit beyond a doubt, they are required 
to deposit as a minimum $25,000 as security with the Committee 
* of Lloyd's. A primary object of the society is the protection of 
the interests of members in respect of shipping, cargoes and freight. 

By no means the least important function of Lloyd's is "the 
collection and diffusion of intelligence and information bearing on 
shipping matters." It has agents all over the world, but these 
agents are not insurance agents; in fact they are strictly forbidden 
to act as such. Their dutie3 may be broadly defined as follows: 
In case of shipwreck to render to masters of vessels, of which 
there are over 40,000 certificates in the British mercantile marine, 
any advice or assistance they may require. Moreover they are 
required to dispatch every item of information likely to be of in- 
terest to the members of Lloyd's by the most expeditious route, 
telegraphic or otherwise, during the day or night, Sunday and 
weekday. It is thus that Lloyd's is enabled to compile and print 
and issue numerous large and instructive books and pamphlets. 

American Bureau of Shipping. — This society was incorporated 
by Act of the Legislature of the State of New York in 1862, for the 
purpose of collecting and disseminating information upon subjects 
of marine or commercial interest, of encouraging and advancing 
worthy and well qualified commanders and other officers of vessels 
in the merchant service, of ascertaining and certifying the qualifi- 
cations of such persons as shall apply to be recommended as such 
commanders or officers, and of promoting the security of life and 
property on the seas. Home office in New York. 

Vessels built in conformity with the American Bureau of Shipping 
Rules and under its inspection are classed thus: 

First Class A 1 for 20 years. 

Second Class A 1 for 16 years. 

Third Class A 1 for 12 years. 



i 



Digiti 



zed by G00gk 



236 HULL CONSTRUCTION 

If built under special survey there is a prefix +. If the machinery 
passes the requirements it is indicated in the registry book of the 
society as M. C. 

British Corporation. — The British Corporation for the Survey 
and Registry of Shipping was founded in 1890 for the purpose of 
providing for the classification of steel ships and the registration 
of vessels classed with the Society, and was appointed by the Board 
of Trade (English) to approve and certify load lines under the 
Merchant Shipping Acts. 

The registry is under the control of the Committee of Manage- 
ment which is composed of shipowners, engineers, shipbuilders and 
representatives of underwriting and other associations, and is in- 
corporated under articles of association wherein provision is made 
that the funds of the Society cannot become a source of profit to 
any member or to any person claiming through any member of the 
corporation. The head office is in Glasgow, Scotland. 

In the British Corporation Rules, items of longitudinal strength 
have their scantlings determined by the length of the vessel in 
conjunction with either breadth or depth. Items of transverse 
strength have their scantlings determined by length or breadth, or 
both combined, no numbers being used, the dimensions alone de- 
termining the scantlings. For example, a vessel 400 ft. long requires 
twenty-five fortieths of shell plating. Vessels built under these 
rules and surveys are classed B. S.* If not under survey but 
under the rules they may be classed B. S. There is only one class 
and not several, as 100 A 1, 100 A, etc., as in Lloyd's. The ma- 
chinery requirements are confirmed with the letters M. B. S. 
The highest class a steamer can receive is B. S.* M. B. S.* 

Bureau Veritas. — This Society has been recognized in France by 
decree of the Minister of Marine Sept. 5, 1908, for carrying out 
the law of April 10, 1907, regarding the safety of marine navigation. 
Vessels holding the highest class of the Bureau Veritas are exempt, 
in obtaining permits of navigation, from examination and tests in 
connection with the hulls, engines, and boilers and their accessories; 
that is to say, on points which are covered by the surveys pre- 
scribed in the present classification rules. 

The Bureau Veritas British Committee has been delegated by 
the Board of Trade in conformity with the Merchant Shipping Act 
of 1894 to assign and mark load lines on their behalf on British 
vessels, also on vessels of other nationalities trading to British 



ioogle 



BOARD OF TRADE 237 

ports and which are not provided with freeboard certificates and 
its marks are recognized as equivalent to British requirements. 

Vessels are divided into three divisions, viz., I, II, and III. In 
order to retain their class, vessels must be subjected to the inspec- 
tion of a surveyor to the Bureau Veritas at the following periods: 

Vessels of the I division every 4 years. 

II division every 3 years. 

Ill division every 3 years. 

The large I denotes first division classification (out of three). 
Two rings around the (p indicate that the ship is divided into a 
sufficient number of watertight compartments so she will float 
with any two in communication with the sea. Very few vessels 
have the double ring, but some have the single ring ® y indicating 
they can float with any one compartment in communication with 
the sea. '/s denotes completeness and efficiency of hull and machin- 
ery; the letter following 8 / 3 indicates the navigation for which the 
vessel is intended for. The first I shows that the wood parts of 
the hull are entirely satisfactory and the second I refers to the 
masts, spars, rigging, anchors, chains and boats. Thus a vessel 
built to the highest class would be given the following characters 
+ 0»A L I.I. 

Norske Veritas. — This Society was established in 1864 by various 
marine insurance clubs of Norway, who prior to its establishment 
had separate surveyors of their own. A large number of Nor- 
wegian vessels are built according to the rules of this society. 
I A I denotes compliance with the rules in regards the hull. M 
& K. V. signifies that the boilers and engines comply. The third 
figure, I, denotes the efficient state of the equipment, and the + 
that the vessel was built under special survey. Thus a vessel built 
to the highest class would be registered thus + I A I I +M& 
K. V. 

Reglstro Nazionale Italiano was formed in 1910 to take over the 
Registro Italiano which was founded in 1861. The society has 
adopted the rules of the British Corporation, and has an arrange- 
ment with the British Corporation by which it can use the services 
of that society in British and foreign ports. 

Great Lakes Register. — Rules under which steamers to ply on the 
Great Lakes, North America, are built. 

Board of Trade. — Although not a classification society, yet the 
Board of Trade is the final authority on British marine matters. 
The Board of Trade gets its authority from the Merchant Shipping 

Digitized by vjOOQ 1C 



238 HULL CONSTRUCTION 

Act of 1894. It has passed regulations on many important subjects 
as freeboard, tonnage, bulkheads, etc. Referring to freeboard, it 
has published tables giving the freeboard of vessels, and has granted 
the right to assign freeboards to Lloyd's, Bureau Veritas, and the 
British Corporation. 

United States Steamboat-Inspection Service, a part of the Depart- 
ment of Commerce with headquarters at Washington, D. C. It 
has inspectors at all the large shipping cities in the United States. 
Rules and regulations are published by it pertaining to the construc- 
tion and inspection of boilers, lifeboats to be carried, wireless equip- 
ment, and other matters relating to the equipment and running of 
motor boats, sail and steam vessels. 

TYPES AND STRUCTURAL FEATURES OF 
MERCHANT VESSELS 

The rules published by Lloyd's Register of Shipping, American 
Bureau of Shipping, Bureau Veritas, or other society, specify the 
size of the frames, beams and other structural members. In Lloyd's, 
for obtaining the scantling numeral which gives the sizes of the dif- 
ferent members, the dimensions used are length (see page 166), 
molded breadth and depth, the latter varying with the type of 
vessel. In Bureau Veritas the same dimensions are used, but in 
the American Bureau of Shipping the half-breadth and half-girth 
are also included in making up the scantling numeral. The differ- 
ence in the frames, beams, etc., for a vessel built according to any 
society is slight, but there is variance in the height of the bulkheads. 

Broadly speaking, merchant vessels have their machinery amid- 
ships, the chief exceptions being tankers, colliers, and lumber car- 
riers. They have double bottoms which are often utilized for 
carrying oil fuel and water ballast. For ships which have to make 
long voyages in ballast, top side tanks together with the usual 
double bottom give a good distribution of the ballast weights. 

Merchant' vessels, according to Lloyd's, can be divided into the 
following classes: shelter, awning and bridge deck, one, two, three, 
etc., deck vessels and sailing vessels. The only reduction allowed 
in the above by Lloyd's is in the shelter, awning and bridge deck 
classes. In all cases the uppermost continuous deck has the heaviest 
scantlings whether shelter deck or otherwise. Freeboard on these 
ships where there are no regular tonnage openings is practically the 
same as on a full scantling freighter. 

Digitized by VjiOOQIC 



MERCHANT VESSELS 



239 



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Figure 35. — Typea of Merchant Vessels. 



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240 . HULL CONSTRUCTION 

Shelter deck vessels (see Fig. 35) are usually three deck vessels 
with a complete erection all fore and aft inclosed from the sea with 
the exception of a few openings for ease in loading and discharging 
cargoes. They have on the upper or shelter deck at the middle 
line one or more openings which are not fitted with permanent 
means of closing like ordinary covered hatchways. 

A shelter deck as now constructed in large vessels is a super- 
structure extending all fore and aft. The peculiar feature is, that 
the 'tween-deck space it incloses is not included in the vessel's reg- 
ister tonnage, this omission being allowed by the existing British 
tonnage laws on the condition that somewhere in the deck there 
is an opening with no permanent means of closing it, and that no 
part of the 'tween-deck space is partitioned off or closed in a per- 
manent manner. The necessary opening, referred to as the tonnage 
opening, may be formed by one of the hatchways, usually the 
after one which may or may not have coamings, but it must not 
have any permanent means of being closed. Sometimes a special 
hatchway is provided about 4 ft. long by half the beam of the ship. 

Shelter deck vessels built to Lloyd's must have the strength 
members carried to the level of the shelter deck. When there are 
no tonnage openings the vessel may be loaded proportionately to 
the structural efficiency of the upper works. When there are ton- 
nage openings in the shelter deck and transverse bulkheads are lo- 
cated in the 'tween-decks closely adjacent to the openings, the 
freeboard has been approximated to that of the normal awning deck 
vessel. Shelter deckers are largely used for carrying cattle, and 
also as bulk oil carriers. See Fig. 40. 

One, two, three, etc., deckers have no awning or shelter decks 
with tonnage openings but continuous decks. These vessels have 
the heaviest scantlings of any built, and are designed to engage in 
ocean trading with the minimum amount of freeboard. 

Sailing Vessels. — Here special attention is given to the transverse 
strength, heavy webs being fitted in way of the masts. The shell 
plating is increased .10 in. when the longitudinal number exceeds 
11,000 and when the number is over 13,000 three strakes at the 
bilge are increased .06 in. Other special stiffening in the shape of 
diagonal tie plates in way of the masts and special panting stringers 
at the ends. 

Hurricane deck vessel is an American term of a type built to 
the rules of the American Bureau of Shipping, This type is divided 
into two classes, viz., one for engaging in the transatlantic and 

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TURRET VESSEL 



241 




Figure 36. — Midship Section of a Turret Vessel. 



general ocean trade (corresponding in many respects to Lloyd's 
shelter deckers except in the heights of the bulkheads) and the 
other for engaging in the coastwise trade, as from New York to New 
Orleans, the latter having lighter scantlings than the former. In 
all hurricane deckers, the depth is taken from the top of the keel 
to the top of the second deck beam amidships at middle line, and 
the collision bulkhead extends only to the second deck. 

The important difference between the two classes is in the fram- 
ing. Vessels built for the transatlantic trade have all their frames 
extend to the hurricane deck, while those for the coastwise extend 
alternately to the second and hurricane decks except for one-sixth 
of the length from the bow where every frame extends to the hurri- 

Digitized by VJ UUv LL 



r 



242 



HULL CONSTRUCTION 



cane deck, but in no case need this exceed 60 ft. As to the reverse 
frames for the transatlantic they extend to the under side of the 
hurricane deck stringer, and for the coastwise for a certain length 
alternately to the hurricane deck. 

Raised Quarter Deck. — Here (see Fig. 35) the main deck is raised 
3 ft. for vessels up to 100 ft. in length, 4 ft. up to 250 ft. and 6 ft. 
up to 400 ft. Although it is customary to speak of the raised quarter 
deck being aDove the main deck, yet neither plates nor beams are 
fitted at the main deck immediately under the raised quarter deck 
except for a short distance at the forward end or at the "break," 
as it is often called. Practically what has been done is to raise up 
the main deck for part of its length. This construction is par- 
ticularly suitable for vessels of about 250 ft., where the machinery 
is amidships, for it gives additional space in the after hold (which 




Figure 37.- 



-Midship Section of a Trunk Vessel. 

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bogle 



WAR VESSELS 243 

is often limited by the shaft tunnel) and thereby prevents a steamer 
from trimming by the head, as the after hold is larger than the 
forward. 

Turret Vessels. — See Fig. 36. These were originally designed to 
save tonnage under the Suez Canal system of measurement. They 
are popular in the Far East trade and are relatively stronger than 
the ordinary* ship of the same dimensions owing to the turret sides. 

They have a continuous center turret which forms with the harbor 
deck an integral part of the hull. They are built without sheer, 
and may have on the top of the turret deck erections as poop, 
bridge, and forecastle, or such erections may be on the harbor deck, 
but in this case the turret must be continuous from the poop to 
the forecastk into which it is scarped. Cutting away the outboard 
parts of the upper 'tween-decks served the double purposes of re- 
ducing the tonnage measurement and port charges, and providing 
a center trunk that served as an expansion chamber and made the 
vessels self-trimming when loaded with grain or similar cargoes. 
They are inferior in stability to the usual type when heeled to an 
excessive angle. 

Trunk Vessels. — These (see Fig. 37) are a modification of turret 
vessels and are of the heaviest type. They have on the upper deck, 
in addition to the poop, bridge', and forecastle, a continuous trunk. 



WAR VESSELS 

The war in Europe (1914r- ) showed particularly the advantages 
of certain types of war vessels, viz., submarines, torpedo boat de- 
stroyers, and battleships, while others which were at one time 
looked upon as important have proved to be of little use. With 
no intention of discussing the advantages and disadvantages of 
every type, yet there stand out preeminently submarines for prey- 
ing on merchant vessels, torpedo boat destroyers for patrol pur- 
poses and to war on submarines, and battleships for shelling land 
fortifications while troops are landing. Modern sea fights between 
armored ships are fought at ranges of 3 or more miles, the guns in 
many cases being elevated so projectiles will drop on the decks, 
thus causing more damage than if fired directly at the sides which 
are heavily protected by armor. 

Aside from the special types of construction for the different classes, 
there should be noted the method of propulsion and the fuels. 

Digitized by VjiOOQ 1C 



244 HULL CONSTRUCTION 

Referring to the former there has been a notable use of steam tur- 
bines either driving the propellers direct or by gears; or the turbines 
may be connected to generators which furnish current to electric 
motors that propel the vessel. See Electric Propulsion. 

Operating conditions for war vessels are different from those of 
merchant. In war vessels it may be necessary to drive the vessel 
at maximum speed at a very short notice, hence the importance of 
water tube boilers for raising steam quickly. Then again a warship 
must have machinery that is economical in the consumption of 
fuel for long distance cruising. Diesel engines have been installed 
chiefly in submarines. As to fuels, many warships are equipped 
for either coal or oil. The chief advantages of oil being that it is 
easier to stow and contains more heat units per pound, thus giving 
a larger steaming radius. 

In the United States Navy all large vessels are framed on the 
longitudinal system (this does not mean on the Isherwood system), 
the keel being continuous as also the fore and aft members on either 
side called longitudinals, while the frames are intercostal. This 
system of framing is carried out from the keel to the protective 
deck including the inner bottom which extends as far forward and 
aft as possible. Above the protective deck the transverse members 
are continuous. Forward and aft of the inner bottom the frames 
are continuous on both sides of the vertical keel and the longitudinals 
are intercostal between them. 

In torpedo boats and small vessels having no inner bottoms the 
frames are continuous from keel to 'gunwale, and closely spaced 
to support the shell plating. Here the longitudinals are intercostal. 
No standard rules, as Lloyd's or British Corporation, are followed, 
the U. S. Navy Department, Admiralty, and the various Govern- 
ment Navy Departments drawing up their own plans and specifi- 
cations. 

Armor. — This may be divided into: (1) broadside extending 
fore and aft sufficiently to cover the ammunition rooms and the 
machinery space; (2) armored transverse bulkheads dividing the 
ship into watertight compartments; (3) armor around the large 
guns which are mounted in turrets; and (4) a protective deck. 

The armor on the sides has a cement backing, back of which is the 

hull plating that in turn is reinforced with heavy frames. The 

armor is bolted to the hull by bolts screwed into the back of the 

• armor. The outer face is given a hard surface while the rear has 

a much softer one and possesses different properties. The manu- 



y Google 



THE PROTECTIVE DECK 245 

facture of a plate either by the Harvey or Krupp process requires 
great care and from 4 to 9 months, depending on the thickness. 
Plates made by either process are alike; that is, they have a hard 
outer surface to resist the penetration of a projectile and a tough 
back to prevent the shattering of the plate by the impact. The 
turret and barbette armor are supported by heavy structural 
shapes and plates. 

The protective deck consists of special treated steel plates about 
23^ ins. thick that slope upwards from the sides of the vessel to a 
flat portion amidships or the deck may extend straight to the shell 
plating. See Fig. 38. This deck serves to protect the machinery 
and other parts below it. 

As an example of the armor of a battleship take the U. S. battle- 
ship Nevada, one of the latest types (1916). The main armor belt 
is 13 J^ ins. thick from its top to 2 ft. below the designed water 
line, whence it is tapered uniformly to 8 ins. at the bottom. Aft 
of the main belt the armor is 13 ins. The forward athwartship 
armor and aftermost armor bulkhead is 13 ins. The barbettes are 
13 and 4J^ ins. thick, the latter being amidships and out of reach of 
the guns of the enemy. There are 4 turrets, 2 having 3 guns each, 
and the other 2 having 2. The 3-gun turrets have 18- and 9-inch 
armor and the 2-gun, 16 and 9. The armor is of the Krupp type. 
There is also a protective deck. 

Armament. — Under this heading are included the guns ranging 
from the 15-inch mounted in the turrets of battleships to light 
saluting guns and also torpedoes. Naval engagements are now fought 
at long ranges and this is due to the development of the modern 
high-powered gun, which brought about the building of the all big 
gun or Dreadnaught type of battleship. 

In the British Navy, 15-inch guns have been installed (Royal 
Sovereign class, 10 15-in., 16 6-in., 12 3-in. or 12-pounders) while 
the largest in the United States (1916) is 14 in., altho battleships 
designed to carry 16-in. guns have been authorized. A popular 
British gun is the 9.2 and a U. S. is the 6-inch, which are largely to 
repel the attacks of torpedo boats and submarines. 

The ammunition is either loose, that is, the powder and the pro- 
jectile are put in the gun separate, or fixed, the powder being in a 
brass case to which the projectile is fastened. Guns 5 ins. and over 
generally use loose ammunition. On some battleships 14-inch 
guns are mounted, firing a projectile weighing about 1,200 lb. and t 
requiring 500 lb. of powder. The powder and projectiles are 



Digiti 



zed by G00gk 



246 



HULL CONSTRUCTION 



stored in ammunition rooms and are brought up to the men operating 
the gun by hoists driven by electric motors or through tubes oper- 
ated by compressed air. The guns in the turret are raised and low- 
ered and the turret turned by electric motors, the turret with its 
armor and guns resting on rollers. Guns using fixed ammunition 
are divided into rapid fire, semi-automatic and automatic. 

Torpedo tubes are of two types, one where the tubes are on deck 
and the other where they are below the water line, the former for 
torpedo boats and the latter for submarines, cruisers, and large 
war vessels. The torpedoes are discharged from the deck tubes by 




—9S'-&i '3ean to outside <fart 

Figure 38. — Midship Section of a Battleship. 

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BATTLESHIPS 247 

a small charge of powder, but after they have cleared the tube and 
the side of the vessel they travel by their own motive power operated 
by compressed air. The driving mechanism for keeping the tor- 
pedo in a straight line and at a given distance from the surface is 
very complicated. At the front is the warhead, which contains the 
high explosive (generally gun cotton) that is discharged when the 
torpedo strikes a ship . Torpedoes are 20 feet or more long, 20 ins. 
or so in diameter and have a range of 2 or more miles. Deck tor- 
pedo tubes are now mounted in pairs, the two tubes being placed 
side by side. Torpedoes from underwater tubes, as fitted on sub- 
marines and other war vessels, are discharged by compressed air, 
the pressure being about 1,200 to 1,800 lb. per square inch. The 
range and when to fire are given from the central station. 
Warships may be divided into the following classes:* 
Battleships. — Designed to fight the most powerful ships of an 
adversary and thus having the heaviest armor and armament. 
Displacement 11,000 to 40,000 tons, speed 16 to 25 knots. The 
term "Dreadnaught" is often applied to a modern battleship, 
which simply means that she has four or more turrets with at least 
13-inch guns, with a secondary battery of 5- or 6-inch. In the 
United States Navy the large guns are in turrets located on the fore 
and aft center line, while in some European countries the turrets 
are on each side (port and starboard). In some U. S. battleships 
having four turrets, two turrets have three guns each, and the 
other two, two guns. In the four battleships authorized in 1916, 
each will have a main battery of 8 16-in., 45 cal. guns. As to 
armor this is the heaviest carried by any vessel; in fact the weight 
of the armor is about 26% of the displacement. The following 
table gives fair values of the weights of armor, hull, etc., of a 
battleship. 



Item 



Weight as Percentage of 
Total Displacement 



Hull 

Armor 

Armament 

Propelling Machinery. 

Coal 

General Equipment. . . 



35.0 
26.0 
19.0 
10.5 
5.5 
4.0 



100.0 



* This division based on one in Naval Construction, by R. H. M. Robinson, 



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248 HULL CONSTRUCTION 

English battleships are fitted with torpedo nets as a protection 
against torpedoes when at anchor. One of the latest types of U. S. 
battleships is the Pennsylvania^ laid down in 1914. Length over 
all 625 ft., water line 600 ft., beam 97 ft., draft 28 ft. 10 ins., normal 
displacement 31,400 tons, turbines 31,500 h. p., speed 21 knots, 
oil fuel only. Has 12 14-inch guns (3 in each turret), 22 5-inch, 
4 3-pounders, 4 21-inch submerged torpedo tubes, 16-inch armor 
belt amidships. One of the latest (1915) English battleships, viz., 
the Royal Sovereign, has' 15-inch guns. Length 630 ft., beam 95 
ft., displacement 29,000 tons, turbines 44,000 h. p., speed 22.5 knots, 
bunkers 4,000 tons of coal. Ten 15-inch guns, 16 6-inch, 12 12- 
pounders, 5 torpedo tubes, armor belt 13 J^ ins., protective deck, 
3 ins. 

Battle Cruisers or Armored Cruisers. — Expected to do some 
advance duty, but capable of taking position in line with battle- 
ships. Have a displacement equal to a battleship, carry heavy 
guns with lighter armor but have a speed of 22 to 31 knots. In 
many instances it is difficult to distinguish between an armored or 
battle cruiser and a battleship. A typical example is the Tiger 
(Great Britain) laid down in 1913. She is 725 ft. over all, 87 ft. 
beam, maximum draft 30 ft., displacement normal 27,000 tons, 
full load 31,000, complement 1,000 men, turbines of 75,000 h. p., 
speed 27 knots, coal normal 1,000 tons, maximum 3,500 plus 1,000 
tons of oil. Has 8 13.5-inch guns, 16 4-inch, 2 submerged torpedo 
tubes on broadside and 1 at stern, 9-inch belt amidships, 4 ins. at 
ends. 

Monitors. — For coast and harbor defense, are now obsolete. 
Had a single turret with 12-inch guns and a secondary battery of 
G- and 4-inch, small freeboard and low speed. U. S. Ozark (1900), 
253 ft. water line, 50 ft. beam, 12 ft. 6 ins. draft, displacement full 
load 3,356 tons. Two 12-inch guns, 4 4-inch, 3 6-pounders, armor 
belt amidships 11 ins., at ends 5 ins., speed about 11 knots. 

Light Cruisers. — These include cruisers with light side armor 
of 2 or 3 ins. and with a protective deck, and those without any side 
armor and with only a protective deck. The heaviest gun usually 
carried is a 6-inch. Light cruisers range from about 3,000 to 
10,000 tons displacement, are speedy and are primarily for preying 
on merchant vessels, while in times of peace they are largely used for 
official business, such as representing their Government at a cele- 
bration at a foreign port. Below are descriptions of two light cruis- 
ers, one with side armor and the other without. Nottingham, 

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TORPEDO BOAT DESTROYERS 249 

British (1914), 430 ft. between perpendiculars, 49 ft. 10 ins. beam, 
displacement 5,400 tons, Yarrow boilers, Parsons turbines of 22,000 
h. p., speed 24.75 knots, coal 650 tons, can also carry oil, 9 6-in. 
guns, 4 3-pounders, 2 21-inch submerged torpedo tubes, 2-in. side 
armor, 2-in. protective deck. Yarmouth, British (1912), 430 ft. 
between perpendiculars, 48 ft. 6 ins. beam, mean draft 15 ft. 3 ins., 
Yarrow boilers, Curtis turbines 24,000 h. p., speed 26 knots, nor- 
mal coal 750 tons, 8 6-in. guns, 4 3-pounders, 2 21-in. submerged 
torpedo tubes, 2-in. protective deck. 

Scouts. — These are seagoing high speed vessels for finding out 
the position of an enemy's fleet. They are lightly built and the 
guns carried are of small sizes. They have no armor and every- 
thing has been subordinated to produce a fast seagoing vessel. 
U. S. Chester (1905), 420 ft. water line, 47 ft. 1 in. beam, 16 ft. 
9 in. draft, displacement 3,750 tons, 4 screws, turbines of total 
16,000 h. p., speed 26 knots, bunkers 1,250 tons. Two 5-in. guns, 6 
3-inch, 2 3-pounders, 2 21-in. torpedo tubes. 

Gunboats. — Small light draft vessels for use on shallow rivers 
and bays. Their displacement is seldom over 1,700 tons, and they 
have a speed of around 14 knots. U. S. Paducah, 174 ft. water 
line, 35 ft. beam, draft 13 ft. 6 ins., twin screw with a total of 1,000 
h. p., speed 12.9 knots, coal normal 100 tons, maximum 236, dis- 
placement 1,085 tons. Six 4-in. guns, 4 6-pounders, 2 1-pounders. 

Torpedo Boats. — About 170 ft. long, 80 to 180 tons displacement, 
lightly built, with a few small guns mounted, and carrying two 
or more torpedo tubes. Have a speed of 28 knots or better, many 
using oil fuel and being driven by turbines. Of recent years, owing 
to the development of submarines, torpedo boats have been little 
used for the purpose they were originally intended for, viz., dis- 
charging torpedoes at larger war vessels and then running away. 
As a class few are now being built. British torpedo boat (1906), 
172 ft. long, 18 ft. beam, 5 ft. 3 ins. mean draft, Parsons turbines, 3 
screws, total 3,750 h. p., speed 26 knots, Yarrow boilers, oil fuel, 
normal 20 tons, 2 12-pounders, 3 18-in. deck torpedo tubes. 

Torpedo Boat Destroyers. — Larger and more powerful than tor- 
pedo boats, carrying heavier guns. Are primarily designed to de- 
stroy torpedo boats, are seagoing, and have a large radius of action. 
Many of the latest types use oil for fuel, and are driven by steam 
turbines. Make good patrol boats and during the European War 
proved of great value in destroying submarines; for on account of 
their speed it is difficult for a submarine to escape when once sighted. 

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250 HULL CONSTRUCTION 

Geared turbines were installed in the U. S. torpedo "boat destroyer 
Wadsworth, which went in commission in 1915. There are 4 ahead 
turbines (Parsons) driving by gears, 2 shafts, while for going astern 
there are two other turbines that revolve in a vacuum when the 
destroyer is going astern. The Wadsworth made 33 knots on trial. 
She is 310 ft. long on water line, 29 ft. 8 ins. beam, mean draft 
9 ft. 4J^ ins., block coefficient .44, displacement 1,050 tons, turbine 
17,500 s. h. p., high pressure turbine 2,495 revs, per min., low 
pressure 1,509, geared down to 450, propellers 7 ft. 7% ins. dia., 
pitch 8 ft. 7]/2 ins., oil burned per knot at speed of 30.72 knots 
507 lb., water per s. h. p., 11.19 lb., carries four 4-in. rapid fire guns 
and four 21-in. twin torpedo tubes. Direct drive turbines are in- 
stalled on many destroyers. 

Submarines. — The war in Europe (1914-) has shown the damage 
these craft can do. At first they were only experimental affairs, but 
now they are seagoing, with a radius of operation of 3,000 to 8,000 
miles or more, and speeds of 14 knots or better per hour when 
running on the surface and 8 or more when submerged. When run- 
ning on the surface they are driven by Diesel engines, and when 
submerged, by storage batteries furnishing current to electric mo- 
tors. Besides being armed with submerged torpedo tubes, the 
latest types have guns, some one or two three-inch. 

The hull may be either single or double. In the former the main 
ballast tank? are located within a strong outer hull, which in sec- 
tion is in the main part circular or nearly so, with elliptical sections 
forward and aft. In the double hull there is a more or less complete, 
strong, pressure-resisting internal hull, which is surrounded by an 
external hull of lighter construction, the^greater part of the water 
ballast being in the space between the two hulls. The single hull 
is represented by the Holland and Lake types as in the United 
States, British, and German navies, and the double hull by the 
Laubeuf . Horizontal rudders are usually fitted at the bow and stern, 
and are sometimes combined with one or more sets of inclining 
planes. In submerging the bow is always slightly depressed. The 
reserve buoyancy varies from 25 to 40%. 

Of the types in the United States Navy are the Holland (built 
by the Electric Boat Co.) and the Lake (built by the Lake Sub- 
marine Boat Co.). In the former the hull proper is circular in cross 
section, on the top of which is built a superstructure, the water 
being allowed to enter and leave it of its own accord, and having 
nothing to do with the trimming. The superstructure is a con- 



ioogle 



SUBMARINES 

Submarines 



251 



Particulars 



U.S. 

K 
Class 



Eng- 
lish 
D 



French 
Bru- 
maire 



U. S.i 



Eng- 
lish 
E 



German 
U-33 , 

to 
U-42 



Length , 

Surface displacement, tons .... 
Submerged displacement, tons. 

Engines 

Horse power, surface 

Speed, surface, knots 

Speed, submerged, knots 

Armament, torpedo tubes .... 
Armament, guns 



153' 4* 

389 

519 

Diesel 

900 

14 * 

10^ ' 

4 



150' 
550 
615 
Diesel 
1200 

14 

8-9» 

3 



400 

550 

Diesel 

850 

$ 

1 



230' 6* 

663' 

912 

Diesel 

2000 

17 
10H 
8 . 



175' 

730 

825 

Diesel 

1600 

15-16 

9-10 

6> 

2 



223' 

665 

822 

Diesel 

2300 

17 

10 

5* 

2 



1 A late design of the Electric Boat Co. * Doubtful. From paper by L. Y. Spear, 
published in Trans. Am. Soc. of N. A., 1915. 

venient means for handling the submarine when coming alongside 
a pier. There is a common tank at the lower part along the keel 
into which the various tanks drain, and from this common tank 
the water is discharged should the submarine desire to come to the 
surface. In some instances the water is pumped out and in others 
forced out by compressed air, the latter being the quickest but most 
expensive. With all deck fittings fast it takes about 2>£ minutes 
for a submarine to get under the surface traveling at J£ speed. 
# The crew depend for air for breathing while submerged on the 
free air in the submarine at the time of submerging and on the 
compressed air carried in the storage flasks, which is used in freeing 
ballast tanks of water as well as for breathing. In the average 
submarine at the present writing (1917) the air contained at the 
time of submerging is sufficient to last the officers and crew 
numbering say 18 men, from 9 to 12 hours. If the air from the 
storage flasks is used^— the time may be increased from 30 to 36 
hours. In computing the time, the safe C 2 (carbon dioxide) that 
should be allowed to accumulate in the air at any time is taken at 
2 per cent. 

In general there are 2 or 3 pairs of rudders, the vertical ones for 
steering to port or starboard, and the horizontal ones for diving 
and rising, assisted by fins forward. In sinking the horizontal rud- 
ders are deflected when under way, water also being taken into the 
tanks. To come to the surface the horizontal rudders are inclined 
and the water is blown out of the tanks by compressed air. 

In the latest Holland types (1916) there are fins on each side 
forward, that are extended when a torpedo is fired, tending to keep 

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252 HULL CONSTRUCTION 

the submarine on an even keel. Forward there are 5 separate 
tubes from which 'the torpedoes can be discharged. Over the ends 
of the tubes fits a cap that revolves so that a torpedo can be dis- 
charged from any tube. 

The Lake submarine has a single hull, with tanks along the keel 
and also on both sides at the top, the top plating of the tanks thus 
forming a flat deck. There are 4 fins, 2 on each side forward and 
the same number aft for steadying when discharging a torpedo and 
keeping the submarine on a level keel. On some there is a small 
vertical rudder aft extending above the deck, besides the one aft 
of the propeller. 

When running below the surface, by means of a periscope ex- 
tending above the water the positions of other vessels are reflected 
so they can be seen by the navigator of the submarine. One of the 
latest models consists of a tube with lenses and at the bottom a 
binocular eye-piece into which the navigator looks. The periscope 
is only for daylight navigation, for when dusk comes it is useless. 
The passing of the image through the various lenses and prisms re- 
duces the brilliancy to such an extent that even if it is magnified 
to above normal the image is so thin it cannot be seen. This forces 
the submarine to become vulnerable in making an attack at night, 
as it is necessary for the conning tower to be brought a sufficient 
distance above the surface of the water for the commanding officer 
to secure natural vision. 

Recent practice is towards building two classes of submarines; 
one about 100 feet or so in length, with a comparatively small 
radius of action, for harbor defense only, and the other of 200 to 
300 feet, that can proceed to sea with the fleet and only have to 
return at long intervals to the home port. 

Submarine Chasers. — These are small seagoing high speed boats, 
carrying 2 or more small guns, and are primarily designed to harass 
and destroy submarines. On account of their size and ability to 
maneuver quickly they are difficult to hit with a torpedo, and with 
their speed they can follow the wake of a submarine when one is 
running submerged, and should the submarine attempt to come to 
the surface the chaser opens fire on her. 

Several were built in the United States in 1915, and below *are 
particulars of one of ten for the Russian Government. Sixty ft. 
long, 10 ft. beam, 2 ft. 10 ins. draft, V-bottom construction with 
the floors flattened aft, oak frames, one-inch cedar planking, 4 steel 
watertight bulkheads, 3 gasoline (petrol) motors each of 175 h. p. ; 

Digitized by vjOOQ 1C 



STRUCTURAL DETAILS 253 

guaranteed speed 26.1 miles per hour, actually made 28, fuel carried 
in four 270-gallon tanks, total 1080 gallons, cruising radius at 26 
miles an hour 500 to 600 miles, accommodations for 6 men and 2 
officers; has 2 rudders, steel deck house forward for pilot, 2 small 
guns. The United States authorized the building of several in 1917, 
110 ft. long. 

Auxiliaries. — These include colliers, repair ships, supply ships, 
and tenders for submarines. They do not carry heavy guns, but 
may have a few small ones to repel torpedo boat and submarine 
attacks. Many are converted merchant vessels, while others are 
specially designed for the service in which they are to be used. 

STRUCTURAL DETAILS 

Systems of Construction. — There are two systems for merchant 
vessels, viz., the transverse as shown in Fig. 39, following Lloyd's 
or other societies' rules, and the longitudinal or Isherwood as in 
Fig. 40. The former has a large number of comparatively small 
frames closely spaced, connected by brackets to beams thus forming 
a complete section. Broadly speaking these transverse sections 
are the fundamental strength members, but to obtain the requisite 
fore and aft strength, keelsons, longitudinals, and stringers are neces- 
sary. See paragraphs on these subjects as also on Frames. The 
transverse system has been universally adopted, although for oil 
carriers and steamers for grain and coal the longitudinal has been 
used mostly in late years. 

In the longitudinal or Isherwood system the transverse frames 
and beams are at widely spaced intervals, the average distance 
being about 12 ft. These heavy frames form complete belts around 
the ship. They are riveted to the shell plating and deck, and arc 
made of not less strength than the number of transverse frames 
that are fitted in ordinary vessels for corresponding length of ship. 
These strong frames are slotted around their outer edges to admit 
of continuous longitudinal stiffeners or frames being fitted not only 
at the deck but on the sides, bottom, and under the tank top. 

The longitudinal stiffeners, being riveted to the deck plating, 
prevent the plating from buckling, which has happened to transverse 
framed vessels having no fore and aft support to the plating be- 
tween the beams. In vessels with double bottoms, transverse floor 
plates are fitted intermediate to those at the sides and decks. Bulb 
angles can be used as longitudinals under the tank top and on the 



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Figure 39. — Transverse System. 

254 



. FRAMING 255 

inside of the shell plating, thereby providing a double bottom which 
is easier of access than one built on the transverse system. See 
Fig. 40. 

In the Isherwood system the inner bottom may extend to the skin 
of the ship whereas in a transverse framed ship it usually stops just 
before the lower turn of the bilge, leaving a space that is of no value for 
carrying cargo. Among the advantages claimed by the Isherwood 
system are increased longitudinal strength, increased deadweight 
carrying capacity, holds free from small pillars, and a reduction in 
the shell plating due to the increased longitudinal strength obtained 
by the fore and aft members. 

The location and number of the bulkheads are the same irre- 
spective of the system of construction. In the following paragraphs, 
excepting frames, keelsons, and those relating to transverse framing, 
the others, as shell plating, bulkheads, etc., in general apply to 
the longitudinal as well as to the transverse system. 

Framing. — Until recent years iron and steel merchant vessels 
were framed on the transverse system, but in certain types, as bulk 
cargo and oil tankers, this has been replaced by the longitudinal or 
Isherwood system. The frames of a transverse framed steel ship 
vary in size and spacing according to the rules, viz., Lloyd's, Amer- 
ican Bureau of Shipping, or other society, to which she is built. 
In Lloyd's rules the frames depend on the transverse number, 
B + D, which is the sum of the molded breadth B and the molded 
depth D, which is the depth at mid-length from top of keel to top 
of uppermost continuous deck, except in awning and shelter deck 
vessels, where it is taken to the deck next below the shelter deck ' 
provided the deck height does not exceed 8 ft., in which case it is 
taken to a point 8 ft. below the shelter deck. A second depth d has 
also to be considered in getting the size of the frames, this depth 
being measured from the top of the floors at the center in a single 
bottom ship, and from the margin plate at the side in a double 
bottom ship, to the top of the beams of the lowest laid deck or tier 
of beams at the side. 

The frames vary in size from 2J4 X 2J4 angles to 12 X 4 X 4 
channels, and in spacing from 20 to 33 ins. from heel to heel, while 
in peak tanks 24 ins., and one-fifth of the length forward to the 
collision bulkhead the spacing is not to exceed 27 ins. 

The framing of a single bottom ship consists of a frame, reverse 
frame, and floor plate. The frame in this case usually extends in 
one length from the center line to the top deck. In deep framing 

Digitized by vjOOQ 1C 



256 HULL CONSTRUCTION 

it is common practice to place a small angle at the lower edge of the 
floor plate overlapping the larger side frame at the bilge, and thus 
save weight. In most merchant vessels deep frames are used in 
conjunction with side stringers formed of plate and angle, thus 
giving a clear hold with unbroken stowage. These deep frames may 
be formed of two angles riveted together, but the more common 
is the equivalent bulb angle or channel section. Web frames and 
side stringers with small intermediate frames can also be used, but 
this construction is not much in favor on account of the interference 
with the cargo. 

The toes of all frames forward of the midship section point aft, 
while those aft of the midship section have the heels aft and the 
toes forward. This gives open bevels and thus room for driving 
the rivets connecting the frames to the shell plating. The frames 
are in some instances joggled, in which case no liners are required 
even if the plating is worked in and out. In fact it is usual 
to joggle the frames for about three-fifths of the length amid- 
ships when they are not more than 10 ins. deep and thus save 
the weight of the frame liners. This makes a better job than 
joggling the plating which is apt to leak and work in a seaway. 
Joggled frames can be employed to advantage in the Isherwood 
system, as they are in rather short pieces, one template doing for 
a large number, the joggling being done cold. 

Reverse frames extend from bilge to bilge doubled in engine and 
boiler rooms; where the framing is built up of frame and reverse 
frame they run up the frame above the bilge, depending on the depth 
d (see above). 

The depth of the floor plates at the center line is governed by the 
same transverse number used for the frames. The floor plates are 
to be molded not less than one-half their depth at a point three- 
fourths the half-breadth of the vessel from the center line and to 
extend up the bilge in a fair curve terminating at a point on the 
frame not less than twice their midship depth at center line, this 
height to be maintained for one-fourth the vessel's length amid- 
ships; they may then be gradually lowered forward and aft until 
the upper edges are level; depending on the shape of the Vessel 
from this point to the ends they may be gradually increased in 
depth to give better connection. In the engine room the floors 
must be increased .04 in. over the midship thickness and in the 
boiler room .10 in. 

The above applies in general to vessels without double bottoms. 

Digitized by VJiOOQ 1C 



FRAMING 



257 



Double bottoms are usually built on the cellular system with solid 
floors either at every frame or on alternate frames, or other con- 
struction followed subject to the approval of the society to whose 
rules the vessel is being built. See also Double Bottom. 



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Figure 40. — Longitudinal or Isherwood System. 

Frames usually extend in one piece from the center line to the 
margin plate and if floors are on alternate frames heavier scantlings 

Digitized by VjiOOQ 1C 



258 HULL CONSTRUCTION 

are required for the intermediate frames. When the vessel's length 
exceeds 400 ft. solid floors are required at every frame* and also 
in single deck vessels which exceed 26 ft. molded depth. 

Reverse frames are generally in one length from the center line 
to the margin plate and doubled in the engine room to the girder 
or longitudinal next beyond the engine seating and under the 
boiler bearers. In double bottoms with floors at alternate frames 
the alternate rsverse frames may be dispensed with provided the 
inner bottom plating be increased .04 in. in thickness. In the 
boiler room the floors are increased .10 in. When floors are on 
alternate frames bracket plates are to be fitted on alternate frames 
at the center line and at the margin plate, and additional girders 
are to be fitted under the engine seating. 

A reduction in the thickness of the shell plating is allowed when 
solid floors are on every frame, provided the thickness does not 
exceed .66 in. 

Shell Plating. — The shell plating may be worked as, in and out 
"strakes, joggled, clinker, or flush as shown in Fig. 41. In and 
out strakes are largely adopted, the keel, bilge, and sheer strakes 
being made outside strakes for ease of removal in case of damage. 
When a vessel is so plated parallel liners are required between 
the frames and' the out strakes. If the plating is joggled no liners 
are necessary, while in the clinker only tapered liners are needed. 
Flush plating calls for extensive linering and is chiefly for yachts 
for appearance' sake, as the liners materially add to the weight of 
the hull. 

The widths of the plates selected should be as near as possible 
the same for all the strakes, thus making the plates interchange- 
able. The following table gives the maximum width of the shell 
plates according to Lloyd's rules. 



Depth of Vessel in Feet 


Maximum Breadth of 
Strake Plating in Inches 


Not exceeding 20 


54 


Above 20, not exceeding 24 


60 


Above 24, not exceeding 28 


66 


Above 28 


72 







The widths are laid off on the midship frame of the body plan 
(one-half fore body and the other after body), and the plate lines 
sketched in, keeping the lines or sight edges parallel amidships 



nvJ^Vl^ 



1 



SHELL PLATING 



259 



and tapered slightly at the ends above the water line, thus requir- 
ing as the stem and stern are approached the working in of stealers 
in the lower strakes, one stealer taking the place of two or more 




5s 








X\ 


=S^ \ 


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ti 


frame j 


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Figure 41.— Shell Plating. 



Digiti 



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260 HULL CONSTRUCTION 

narrow strakes of plating. In the after body the plating between 
the oxter and sheer strake is divided into the same number of 
strakes and lines run in, stealers being employed where necessary. 
By so dividing the strakes, all the difficult work may be in one 
plate, that is, in the oxter, instead of in several. The above pro- 
cedure is followed in laying out the plating for a single screw vessel. 
In a twin, triple or quadruple screw the forebody is worked the 
same as for a single, but in the after body care must be taken in 
laying out the plating around the shaft tubes so the plates may be 
easily worked, short plates being selected for furnacing. 

Coincident with the laying out of the shell plating on the body 
plan and the making of a drawing of the shell expansion, a model 
is made. In large vessels the plates may be 24 to 28 ft. in length, 
but care must be taken in selecting a length that can be easily 
handled. In ordering shell plates it is usual to take the widths 
from the mold loft and only the lengths from the model as this 
gives less scrap. 

The thickness of the plating, sizes of laps and butts are given 
in the rules of the classification societies. In Lloyd's there is 
now no garboard strake except in the case of a vessel with a bar 
keel. Bottom and bilge plating all have the same thickness. In 
some large vessels the sheer strake is doubled for half the length 
amidships. The thickness of all the strakes is greatest amidships 
and is gradually reduced at the ends, although doubling plates are 
required around cargo ports, hawse pipes and other parts subject 
to excessive local stresses. When lap butts are selected the laps 
should face aft, so that when the vessel is moving alongside a pier 
no projecting parts will catch; and furthermore there is no resist- 
ance offered by them when the ship is moving through the water. 

In laying out the shell plating a good shift of butts should be 
secured and they must not come* in the same frame space as those 
of the keel, tank top plating, longitudinals or deck stringers. 
Lloyd's rules state: no butts of outside plating in adjoining strakes 
to be nearer each other than two frame spaces, and the butts of 
alternate strakes must not be under each other, but shifted not 
less than one frame space. The sheer strake must extend suffi- 
ciently above the* upper deck ends to take at least two rows of 
rivets vertically in the butts above the upper flange of the gunwale 
bar. 

All shell plates are flush riveted with perhaps the single exception 
of the sheer strake in large vessels where there are doubling plates, 

Digitized by VJiOOQ LC 



BULWARKS « 261 

in which case the riveting may be done by machine, the rivets 
being given button points. In fitting doubling plates tack rivets 
are driven along the edges as also in the middle portions of the plates. 

Lloyd's requires all flush butts of plating to be planed and fitted 
close, all overlapped butts and edges to be sheared from the faying 
surfaces, or the burr caused by shearing to be carefully chipped 
off, and all outside edges of seams and lapped butts to be either 
planed or chipped fair. The rivet holes are to be punched from 
the faying surfaces, opposite each other in the adjoining parts, 
laps, lining pieces, buttstraps and frames. 

In the garboard strake or the strake next to the keel brass plugs' 
are sometimes fitted, by unscrewing which when in dry dock the 
inner bottom compartments may be drained. 

Bulwarks. — These are sometimes fitted forward to keep the 
water off the deck, or in the wells of large vessels, or on bridge or 
promenade decks. The plating is usually light of about 12.5 lb. 
and may be supported by wrought iron stanchions, by flanged 
plates or by bulb angles, spaced not more than 6 -ft. apart, and the 
top finished off with a bulb angle or channel. Teak rails are only 
fitted on passenger steamers and then very rarely on account of 
the cost. In the bulwarks are openings called freeing ports for the 
water to run off the deck, and also openings through which the 
lines for handling the vessel can pass. 

Double or Inner Bottom. — This is important as it serves not 
only to prevent water from entering the ship should the shell plat- 
ing be pierced, but also provides a means for carrying water ballast. 
or oil fuel. It extends approximately from bilge to bilge, and 
as far forward and aft as practical. The frames and reverse frames 
are usually joggled in a double bottom as they are smaller than the 
main frames which are connected by brackets to the margin plate, 
the margin plate being near the turn of tha bilge. See Fig. 39. 

The breadth of the bracket at the ship's side and its rivet attach- 
ment to the frame angle must in no case be less than its breadth 
and attachment at the margin plate. At the lower edge of the 
margin plate is a continuous angle riveted to the shell, while the 
upper part of the plate is flange4 over, generally inboard, and riveted 
to the inner bottom plating (tank top). A gusset plate is riveted 
over the flange of the margin plate and also to the reverse angle 
of the vertical frame, depending on the size of the ship. If the ship 
is large enough to have gussets at every frame it is usual to carry 

Digitized by VjiOOQIC 



262 



HULL CONSTRUCTION 



the double bottom plating over on the margin brackets and an angle 
is fitted at both the top and bottom of the margin plate. 

Instead of the above construction the tank top may extend 
to the shell plating with an angle connection, and be flanged con- 
nected thereto at the ends. A flanged plate is employed at the 
ends on account of the difficulty of riveting an angle to the shell 
and tank top. The frame bracket is riveted to the top of the 
tank top, but this construction interferes with the stowage of 
cargo and is not adopted as extensively as the one outlined in the 
previous paragraph. 

The thickness of the plating is specified by the rules. Under 
the boilers it is increased in thickness. The seams run fore and 
aft, and care must be taken to secure a good shift of butts that 
will not coincide with those of the shell, center keelson and longi- 
tudinals. The plating may be either alternately in and out or 
one edge in and the other out. 

When a double bottom extends through the engine and boiler 
spaces, a well should be formed between the after engine room 
bulkhead and the floor immediately forward of it for drainage 
purposes, or open gutterways of sufficient size should be made in 
the wings so as always to be accessible. To give* access to the 
floors and longitudinals manholes are fitted in the tank top; these 
manholes may be plates bolted to the plating or they may have 
hinged covers that can be bolted down. 



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Figure 42. — Bar Keel. 



Where the side girders are spaced more than 6 tt. apart the 
watertight floors in double bottoms are to be stiffened by vertical 

Digitized by VjiOOQIC 



AIR PIPES, THE TANK TOP, ETC. 263 

angles of the size of the frame angle on the floor, spaced midway 
between the girders. Every floor in the engine space should have 
double reverse angles, as also on each floor in way of boiler bearers. 
They are to extend in all cases from the middle line to beyond 
the girder next outside the engine seating. 

Air pipes should be fitted in sufficient number and size and 
wherever necessary, one being at each end of each tank on both 
sides of the vessel. 

The tank top may be covered with a bituminous compound instead 
of a wood ceiling (see Carpenter Work), the former having the advan- 
tage of well protecting the plating when properly applied. 

Keelsons and Longitudinals or Side Girders. — In a vessel without 
a double bottom there is a fore and aft center plate with angles 
at the top and bottom, called the center keelson, and between it 
and the turn of the bilge, one or more plates with angles called side 
keelsons, and at the bilge another of similar construction called 
a bilge keelson. These same members in a vessel with a double 
bottom are often given the names of center girder and side girders 
or longitudinals, which in the latter case are numbered as first 
longitudinal, second, and so on. 

The center girder is continuous fore and aft and is riveted to the 
tank top and to the keel, and also to the stem and stern post. It 
is usually watertight but not necessarily caulked, although the rivets 
may be given a watertight spacing. In the way of tanks it is 
caulked. Lloyd's recommend "that keelsons be carried fore and 
aft continuously through bulkheads, the latter being made water- 
tight around them. Side and bilge keelsons are fitted with inter- 
costal plates attached to the shell plating by angles as may be 
required. All angle and bulb angle bars of keelsons are to be in 
long lengths, properly shifted and wherever butted to be connected 
with angles not less than 2 ft. long fitted in the throat of them, 
properly riveted to each flange." See section on Oil Carriers. 

Longitudinals are intercostal in some vessels between the frames, 
while in others, as in battleships, they are continuous, the frames 
being cut. They have lightening holes, but in large vessels with 
several longitudinals one or more of them are made watertight. 
Wherever possible they should be arranged so that in the engine 
room they form part of the engine foundation. They should not 
be stopped abruptly, but be gradually reduced in size beyond ths 
distance they are called on to extend by the rules. 

Digitized by VjiOOQIC 



264 



HULL CONSTRUCTION 



Instead of running the keelsons continuously through the bulk- 
heads they may be stopped and bracketed to them. 

Keels. — Figs. 42 and 43 show different types. Flat plate keels for 
large vessels, while for tugs, lighters and other small craft, bar keels. 
With flat plate keels intercostal keelson plates or vertical center 
plates must be fitted close down on the keel plate and connected to 




£65 ' Sf earner 



Figure 43.— Plate Keel. 



it by double angles riveted all fore and aft to the keel plate and 
keelson. Bar keels should be worked in long lengths, connected 
together by rigfft and left hand scarphs that are generally nine 
times the thickness of the bar in length. 

Bilge keels may be of a single bulb angle or of a plate and 
angle, or bulb plate and T bar or plates arranged with a V-cross 
section packed with wood and riveted to angles that in turn are 
riveted to the shell. Bilge keels are to prevent excessive rolling and 
extend about two-thirds or less of the length of the vessel; they 
should be carefully located so as not to retard the speed. A 160-ft. 
steamer had fitted bilge keels consisting of a 5-in. X 4^in. X 15-lb. 
T bar to which was riveted a 10-in. X H-in. bulb plate. In large 
vessels the keels may be 24 ins. or more in width. 

Docking Keels.— Only installed on war vessels; consist of a 
fore and aft timber about 12 ins. wide by 6 ins. thick, connected 
to the shell plating by angles. The keels should be placed under 
longitudinals so when the vessel rests on them in dry dock the shell 
plating will be well supported. They extend a little over one- 
half the length of the vessel. 

Deck Plating and Coverings. — The plating is riveted to the deck 
beams and is laid with alternate in and out strakes, or one edge of a 

Digitized by VjOOQLC 



DECK PLATING 265 

strake in and the other out, or the plating may be flush or joggled. 
When the plating is not to be covered the strakes may be arranged 
in and out so that water on the deck will flow towards the water- 
ways, and thence through the scuppers and overboard. Flush decks 
made by joggling down the beams and fitting joggled plating are 
much cheaper than flush decks with planed and fitted edge laps, 
equally efficient for trucking, and better from the riveting and 
structural point of view. Strake next to the shell; that is the 
stringer is heavier than the others. The plates are ordered in long 
lengths, the seams running fore and aft, the sizes of laps and butt- 
straps are given by the rules (Lloyd's, American Bureau of Shipping, 
etc.). All the riveting has watertight spacing and the plate edges 
caulked. 

The deck plating is invariably continuous, the bulkheads being 
intercostal (see Bulkheads). When the frames extend through a 
watertight deck, stapling may be worked between the frames and 
riveted to them as well as to the deck and shell plating, after which 
the stapling is caulked. Or, as more usually the case, the frames 
are cut and bracketed to the watertight deck or flat. 

Deck planking (see Carpenter and Joiner Work). 

When vertical donkey boilers are placed on a steel deck, the 
deck underneath them is to be covered with fire brick or cement 
not less than 2 ins. thick. The deck on which fires may be drawn 
from a donkey boiler is also to be protected by fire brick or cement 
not less than 2 ins. thick. 

In the galley, toilets, bathrooms, and where it is necessary to 
flush the floors frequently, other material than wood is laid for 
covering the steel deck.. In some instances linoleum, it being 
fastened down by cement or by metal strips bolted to the deck. 
In the toilets and bathrooms either rubber or clay tiling embedded 
in cement or an asphalt flooring may be laid. 

Deck beams are connected to the frames by knees or brackets 
which are in accordance with Lloyd's or other societies' rules. The 
beams on the upper decks are given a camber of about ]/i of an inch 
to the foot in the ship's width. Those on the lower decks and in 
the holds are often straight. 

Beams are to be fitted at every frame: 

(a) At all watertight flats; 

(b) At upper decks of single deck vessels above 15 ft. in depth; 

(c) At unsheathed upper decks when a complete steel deck is 

Digitized by VJiOOQ 1C 



266 HULL CONSTRUCTION 

required by the rules, also at unsheathed bridge decks, 
awning or shelter decks. In vessels over 450 ft. in length 
the beams of the upper, awning or shelter decks are to be 
fitted at every frame whether the plating is sheathed or 
not. Upper decks in way of poops, forecastles and bridges 
of vessels not exceeding 66 ft. in breadth may have the 
beams fitted at alternate frames except for one-tenth the 
vessel's length within each end of the bridge where they 
are to be fitted at every frame; 

(d) Where no wood deck is laid on a steel or iron deck (required 
by the rules) at sides of hatchways including those of engine 
and boiler room openings. 

Elsewhere deck beams must in no case be spaced more than two 
frame spaces apart and only when the frame spacing does not ex- 
ceed 27 ins. (Lloyd's requirements). 

When it is intended to suspend chilled beef or similar products 
from the beams, the beams and the girders under them must be 
of extra strength. Strong beams in the machinery space are to 
have double angles on their upper and lower edges unless cross tie 
plating is fitted on them, in which case only single angles are re- 
quired on the upper and lower edges. 

Single deck vessels can be built according to Lloyd's without 
any intermediate hold beams; in fact the rules cover single deckers 
up to 31 ft. in depth. 

Hatchways. — Beams forming the end of hatchways above 10 ft. 
in length where beams are at every frame are to be not less than the 
size required for beams at alternate frames. To the deck are 
riveted angles which are riveted to coaming plates. The thickness 
of these plates is according to Lloyd's or other societies' rules and the 
angles connecting same are to be the same thickness as the plates 
and welded at the corners. 

Side coamings are to extend below the beams and be flanged 
for a breadth of 6 ins. under the half-beams when hatches exceed 
10 ft. in length, and also are stiffened near the top by horizontal 
bulb angles not less than 7 ins. in depth or their equivalent. The 
athwartship plates may be worked with an incline or pitch, the 
highest part being at the center, and they are not given the camber 
of the deck beam as the hatch covers will fit better without it. 
See Hatch Covers. 

Digitized by LiOOQ IC 



HATCH OPENINGS 



267 




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Figure 44. — Section Through Hatch Coaming. 

Height of Coamings. — On upper, awning or raised quarter deck 
exposed 24 ins. 

On decks of superstructures other than awning decks, where 
exposed to the weather, within one-quarter length from the 
stem 24 ins., when aft of one-quarter length, 18 ins. 

On decks inside superstructures, the openings in the latter 
having no means of closing, 18 ins. 

On decks inside superstructures the openings in the latter 
being closed by strong wood doors or shifting boards fitted in 
channels, 9 ins. 

On decks below the upper or awning decks or within an 
intact superstructure the coaming plates need not extend 
above the deck, but in such cases an angle coaming should 
be fitted around these hatchways. 

Hatch openings should have round corners on weather decks 
and on the top of the coaming plate have riveted either a special 
rolled section (see Fig. 44), or a Z bar. On the outside are cleats 
spaced about 9 ins. from the corners and 2 ft. apart, and at such 
a distance from the top that the tarpaulin cover can be easily 

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r 



268 HULL CONSTRUCTION 

fitted when the battening bar, say 2\4 his. X X A in., is placed in 
position. On the sides are two or three lashing rings. 

On large hatches heavy portable fore and afters and beams 
are fitted (maximum spacing 4 ft. 6 ins.) to support the covers 
efficiently. 

Pillars or stanchions are of wrought iron pipe or of plates and 
angles extending from the beams of one deck to the plating of the 
one below. In vessels with several decks or tiers of beams, in 
order that the stanchions develop their full efficiency they should 
extend from the center keelson or tank top to the upper deck as 
nearly as possible in a vertical line so as to form a continuous tie, 
the upper stanchions being fighter than those in the hold. 

It is now the practice in cargo steamers to have large stanchions 
widely spaced; a single row for vessels up to and not exceeding 
44 ft. beam, double row from 44 ft. to 50 ft. and three rows above 
50 ft., which may support fore and aft girders fastened to the 
under side of the deck and to the deck beams. With this arrange- 
ment holds are obtained that are free from a number of small 
pillars. An example of a girder and pillar is shown in Fig. 45. 

Stringers. — These are continuous angles on the inside of the 
frames, and when the frames exceed a certain depth, Lloyd's re- 
quires intercostal plates to be fitted, attached to the shell plating 
by angles of the thickness of the intercostal plates. The stringer 
angles are attached to each reverse frame or to angle lugs on the 
frames with at least two rivets, and connected by brackets to the 
transverse watertight bulkheads. They should be perpendicular to 
the shell, thus giving the maximum support to it. The outboard 
angles should be worked straight without any bevel. When the 
stringers are 18 ins. in width or over, Lloyd's requires bracket plates 
to be fitted below them, except, however, should the web frames 
in the vessel be spaced 8 ft. apart. 

Panting stringers consist of plates and angles similar to side 
stringers and are located forward to stiffen the frames and shell 
plating, as the comparatively fiat surfaces of the plating have a 
tendency to pant, that is, move in and out in a seaway. The 
panting stringers from both sides are connected at the stem to a 
common plate called a breasthook. 

Bulkheads. — The number and height of watertight bulkheads 
are fixed by the rules (in Great Britain by the Board of Trade) 
under which the vessel will be built. Watertight transverse bulk- 
heads are of value as they give structural strength, prevent fires 

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BULKHEADS 



269 



C///9 Ad ofccA 
/ rWcrte prefer s&ecA 




a/ p///crr 




Spec/a/ afS/ffe/tt/Ty 

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2 frcr/7?e spaces 



L oppeefp/crfe 
arp/pe c/epe/ttf/Tp 
o/j s/ze 



t-oca/ cfoi/6/er 
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Figure 45.— Hold Pillar. 

from spreading, and also prevent water from flowing into other 
compartments should one compartment be flooded. Longitudinal 
bulkheads are valuable structurally as they form a vertical web, 



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270 



HULL CONSTRUCTION 



thus adding greatly to the fore and aft strength of a vessel. Battle- 
ships, tankers and large passenger vessels have suqh bulkheads. 

Lloyd's states: "Screw steamers are to have a watertight bulk- 
head at each end of the engine and boiler space. A watertight 
collision bulkhead is in addition to be fitted at not less than 5% 
of the vessel's length abaft the fore part of the stem measured at 
the fore part of the stem at the load waterline and a watertight 
bulkhead is also to be fitted at a reasonable distance from the 
after end of the vessel. 

"The foremost or collision bulkhead is to extend from the floor 
plates to the upper, awning or shelter deck and its watertightness 
is to be tested by filling the peak with water to the height of the 
load line. 

"In vessels above 285 ft. and not exceeding 335 ft., an additional 
bulkhead is to be fitted in the main hold about midway between 
the collision and boiler room bulkheads. 

"In vessels above 335 ft. and not exceeding 405 ft. two additional 
watertight bulkheads are to be fitted one in the fore hold and one 
in the after hold. 



Vessels Above 


And Not Exceeding 


Additional Watertight Bulk- 
heads to be Fitted 


405 ft. 
470 " 
540 " 
610 •" 


470 ft. 
540 " 
610 " 
680 " 


3 
4 
5 
6 



"Where the machinery is fitted aft in vessels above 220 ft. and 
not exceeding 285 ft., a watertight bulkhead is to be fitted about 
midway between the collision bulkhead and the bulkhead at the 
fore end of the engine and boiler space. 

"The bulkheads are to extend to the height of the upper deck 
except in awning or shelter deck vessels in which cases the bulk- 
heads with the exception of the collision, may extend to the deck 
next below the awning or shelter deck. In awning or shelter deck 
vessels with a continuous superstructure or bridge house a deep 
web frame or partial bulkhead is to be fitted on each side in the 
'tween-decks over each of the watertight bulkheads which extend 
only to the deck next below the awning or shelter deck. Partial 
bulkheads may be dispensed with if other efficient strengthening 
is provided to the satisfaction of the Committee. The after col- 



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THICKNESS OF THE PLATING 271 

lision bulkhead may extend to the first deck above the load line 
subject to the approval of the Committee, provided this deck 
forms a watertight flat from the bulkhead to the stern, otherwise 
it must extend to the upper deck." 

American Bureau of Shipping states: "All vessels must have a 
forward watertight collision bulkhead extending to the upper and 
to second deck in hurricane deck vessels. As to the after collision 
bulkhead this is to extend to the upper deck, second deck in hurri- 
cane and three deck vessels and have a watertight steel flat extend- 
ing aft from it to the stern post so as to form a watertight com- 
partment around the stern tube for the screw shaft." 

The Bulkhead Committee of the British Board of Trade issued 
a report in 1915 requiring that all vessels carrying 12 passengers 
or over must be subdivided according to definite standards. The 
most important factor regulating the subdivision is the freeboard 
ratio or the ratio of freeboard to draft. If this is small, the surplus 
buoyancy of a vessel is small and the spacing of the bulkheads is 
close. If large holds are required the freeboard ratio must be 
considerable, which may be obtained by either limiting the draft 
or increasing the depth. In some cases the bulkheads are carried 
to a deck higher than what would otherwise be the bulkhead deck. 

The plating of transverse as also longitudinal bulkheads is 
invariably worked intercostal between the decks. In transverse, 
the plating may be either in vertical or horizontal strakes, or a 
combination of the two. By using a vertical plate on each side at 
the shell, the others may be rectangular with the seams horizontal 
if desired. The side plates are connected to the shell by single or 
double angles as called for by the rules, and the upper plates to 
the deck by single or double angles. As the holes caused by the 
riveting of two angles to the shell weaken the shell, this is strength- 
ened by adding doubling plates or liners. Lloyd's states that 
doubling plates between frames and outside plating in way of bulk- 
heads are to extend in one piece from the foreside of the frame 
before to the afterside of the frame abaft the bulkhead frames, or 
they may be of an approved diamond shape. These doubling plates 
may be dispensed with provided the transverse watertight bulk- 
heads are connected to the sides of the vessel by brackets, fitted 
at each side stringer and hold stringer. 

The thickness of the plating varies, the lightest being at top. 
The plating is stiffened by vertical stiffeners bracketed in some 
instances to the deck, and to the tank top as may be required by 

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272 HULL CONSTRUCTION 

the rules, which also give the thickness of the plating and the 
riveting. Vertical stiffeners are the only ones (except in tankers 
which also have horizontal stiffeners) 'required by Lloyd's in accord- 
ance with the tables issued in May, 1915. In torpedo boats and 
in other high speed vessels, instead of vertical stiffeners the plates 
are sometimes flanged, thus saving weight. 

To secure waterti^htness bulkheads must > be caulked, and this 
is usually done on the after side of bulkheads forward of amid- 
ships, and on the forward side of those aft. The stiffeners are 
arranged so they do not come on the side to be caulked. As 
a rule it is necessary to caulk only one side of a bulkhead. In 
tankers the greatest care must be exercised to get oil tightness, not 
only by spacing the rivets closer but by additional care in caulk- 
ing. See section in Oil Carriers. 

Stopwaters. — These consist of packing pieces or liners applied 
locally. They are fitted when the caulking edge is inaccessible, 
as in a watertight bulkhead when stiffeners are placed on the caulk- 
ing side crossing the seams of plating. Stopwaters may be of 
canvas, burlap, or felt soaked in red lead, in tar, or a mixture of 
red lead and tar. One of the best materials is hempfelt sheeting 
soaked in tar. 

Stem and stern frames may be of cast steel or of forgings. In 
large vessels they are in two or more parts riveted together. Their 
sizes are specified in the rules, Lloyd's, American Bureau of Ship- 
ping, etc. In bar keel vessels the lower part of the stem is of the 
same molding as the keel and is fastened to it by a scarph of the 
same length as the keel scarph (see Keels). In flat keel vessels the 
center keelson extends well forward and is riveted to the stem 
when possible and in addition the angles on each side of the center 
keelson extend as far forward as practical and are riveted to the 
stem as well as to the flat keel. 

The stern frame consists of two posts, the forward or body post 
and the after or stern post, that are connected at the bottom by a 
flattened portion, and at the top by an arched. In vessels whose 
longitudinal number (Lloyd's) is over 16,000 the forward or pro- 
peller post should extend sufficiently above the arch of the stern 
post to be efficiently connected to the plating on the beams and 
to a deep transom plate. In single and triple screw vessels the 
body post is swelled out to take the stern tube. The spur or heel 
for connecting to the keel (bar or flat) is usually 2 l A frame spaces 
long. The center keelson is connected as outlined for the stem. 



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STERN TUBE 273 

To the after or stern post are forged or cast (depending on whether 
the post is a forging or a casting) gudgeons for the rudder pintles. 
The upper gudgeon should be as near as is practical to the rudder 
trunk, while the others are 4 ft. C ins. to 5 ft. apart. One of the 
gudgeons in small vessels and two in large are shaped so as to* form 
a hard-over stop for the rudder. At the bottom of the stern post 
there may be a spur extending aft that takes the lower rudder 
pintle. Gudgeons must not be less in depth than seven-tenths the 
diameter of the rudder head, and the thickness one-half the diam- 
eter of the pintles. The stern post must extend sufficiently above 
the counter to be connected to the full depth of the transom plate. 

Stern Tube. — This in a single screw vessel extends from the stern 
post to the after collision bulkhead. The after end at the stern 
4 post has a composition bushing with lignum vitae strips, with the 
grain set perpendicular to the shaft. The shaft in the way of 
the strips has a brass sleeve. At the collision bulkhead is a stuffing 
box. 

Propeller Struts. — These are usually of cast steel with an elliptical 
cross section, the forward part having a larger radius than the 
after. The center of the strut should be placed on a frame so as 
to secure the maximum stiffness. In wake of the upper palm 
doubling plates should be fitted on the shell plating, while the 
lower palm should be riveted to the keel. Struts should be set so 
as to conform to the run of the water, so the arms will not cross the 
stream lines and interfere with the speed of the vessel. 

Simpson's formula* for propeller struts is as follows: 
R = revolutions of engines per minute 
P — indicated horse power for one shaft only 
I = outboard length of shaft from stern tube outer bearing to 

center of boss in ins. 
k = coefficient =» .0633 R 

. , </R XPXl 
Then area in squaro inches = -r 

The proportion s of the pea r-shaped arm are: 
Length = \/ 5.3 X area 
Distance maximum breadth from the forward end = .33 X 

length 
Maximum breadth = .25 X length 
Radius at forward end = .25 X maximum breadth 
Radius at after end = .50 X radius at forward end. 

*From The Naval Constructor, G. Simpson. 

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274 HULL CONSTRUCTION 

For the lesser powers and for brackets intended for wood of 
composite vessels, the brackets should be of gun metal or bronze, 
and for higher powers and steel ships of cast steel. 

Spectacle Frames. — These have taken the place of propeller 
struts in large twin and triple screw vessels. They are of cast 
steel and their cross section may be calculated by the same formula 
as for propeller struts and the result multiplied by two, as in this 
case there is only one arm whereas in the other there are two. The 
shell plating is worked completely around the frames, thus inclosing 
the propeller shaft. Additional strength must be obtained in 
wake of the spectacle frames by increasing the floors and doubling 
the ship's frames. 

Rudders may be of cast steel, or a steel plate riveted to wrought 
iron arms, or a wrought iron frame packed with wood and then 
covered with steel plates. Cast steel rudders, particularly if only 
one is required, are expensive, while those packed with wood are 
heavy. The most satisfactory is a single plate riveted to arms 
on alternate sides, the plate varying from % to \ x /i ins. in thick- 
ness depending on the size of the vessel. 

A quick formula for calculating the diameter of the rudder stock 
is given in the British Corporation rules (see also Lloyd's, Amer- 
ican Bureau of Shipping, etc.) as follows: 

Let d = diameter of stock in ins. 

A = area of rudder in sq. ft. 

r = distance from center of gravity to axis in ft. 

V = speed in knots 
Then d = .26 \/ r A F* 

The rudder stock may have a vertical or horizontal palm, which 
is bolted to a corresponding one on the frame, a key being inserted, 
or the parts may be scarphed together. The pintles should be 
separate from the rudder frame and of a cone shape (see Fig. 46) 
and one, called the locking pintle, must have a nut to prevent the 
rudder from jumping in a seaway. To the rudder stock is keyed 
either a tiller or a quadrant — if the steering engine is located 
forward. If a tiller is selected it is necessary to have sheaves to 
take up the slack rope, but if a quadrant no sheaves are necessary. 
See Steering Engines. 

The forward side of the rudder frame is made preferably in one 
continuous line with the projections for the pintles forged or cast 
on, as by so doing a strong frame is obtained. To nil in the spaces 

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4 



Passenger j Cargo Sf earner 



State Wfree/ Stee/ner 








RW 

§ 






j3a/f/e Sh//> 




Figure 46. — Rudders. 
275 



Digiti 



zed by G00gk 



276 HULL CONSTRUCTION 

between the pintles, plates are riveted to the outside of the frame. 
Rudders for sidcwheelers often have a bumpkin at the after part 
to which the steering gear is attached. In this case the rudder is 
turned by pulling on the bumpkin, the rudder post serving only as 
a pivot. 

As to shapes there is a variety as shown in Fig. 45. For tugs, 
lighters and side-wheel steamers the maximum width is near the 
load water line and the area is large. For ocean-going vessels the 
area is smaller in proportion to their length and the maximum 
width is about % from the load water line. The balanced rudder 
is extensively used, particularly on warships. In this type a por- 
tion of the area is forward of the rudder stock. The rudders of 
warships are broader and shallower than those of merchant vessels 
so as to keep them and the steering gear well below the water line. 

Below are ratios of the areas of rudders to the areas of lateral or 
longitudinal planes of different types of vessels. 

Ratio of Area of Rudder to Area of Lateral Plane* 



Type of Vessel 


Unbalanced 
Rudder 


Compensated 
Rudder 


Paddle wheel 


.021 
.016 
.020 
.025 




Large passenger 




Ordinary screw 


.024 


Armored ships 


•030 







As an example take the U. S. fuel oil ship Cuyama f 455 ft. long, 
56 ft. beam, 35 ft. 9J^ ins. depth of hold, trial displacement 14,500 
tons, speed loaded 14 knots, rudder of balanced type, area to 26 ft. 
4 ins., water line 190 sq. ft. abaft of pintles and 35 sq. ft. forward 
of pintles, total area 225 sq. ft., extreme working angle of rudder 
from amidship to hard over,' 35°. Engine, two-cylinder, each 10 
ins. dia. by 10 ins. stroke, steam 125 lb., can put rudder hard over 
in 30 seconds when vessel is going full speed. 

Where the rudder enters the counter there is a watertight trunk, 
which should be of sufficient size so the rudder may be readily 
unshipped. For appearance* sake and to prevent the constant 
flowing in and out of the water, the lower part of the trunk is cov- 
ered over by a bolted plate. 

Suitable stops for the rudder should be securely fastened to the 
deck in way of the tiller or quadrant. When the quadrant is geared 
direct to the steam steering engine the deck stops may be dispensed 

* From Naval Architecture, C. H. Peabody. 

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MACHINERY FOUNDATIONS 277 

with. The stops for the steering engine should be at a smaller 
angle of helm than the rudder stops. 

Machinery Foundations. — Foundations for the engines, boilers, 
pumps, and auxiliary machinery should be well and strongly built. 
Scotch boilers should be kept up high enough to allow a man to get 
under them and also there should be room between them and t!:e 
deck above to adjust safety valves and other boiler fittings. Care 
should be taken that the boiler saddles do not come in line with the 
circumferential seams of the boiler, as the latter at the bottom of 
the shell are liable to leak. The U. S. Steamboat-Inspection Rules 
state: "All boilers shall have a clear space of at least 8 ins. between 
the underside of the cylindrical sheet and the floor or keelson. All 
boilers shall have a clear space at the back and ends thereof of 2 ft. 
opposite the back connection door, provided that on vessels con- 
structed of iron or steel with metal bulkheads the distance back 
of the doors and such metal bulkheads shall not be less than 16 ins." 

In Scotch boilers the saddles may extend a distance of about % 
of the diameter of the boiler around the bottom. The boilers 
rest on these saddles and may be connected to them by rods from 
pad eyes riveted on the boiler to others on the saddles. Or instead 
of this, plates may be riveted to the boilers at each side and these 
plates bolted to I beams extending fore and aft that are fastened 
to the floors, in which case no rods are required. In both cases, 
to prevent fore and aft movement of a boiler, chocks consisting 
either of a casting or built up of plates and angles are fastened 
to the tank top at the forward and after ends. 

Water tube boilers should be located so that their drums are 
readily accessible. 

In laying off engine foundations give all heights from the center 
of the shaft down and allow' % to 1 inch for lining up. They 
should if practicable be part of the longitudinals, or if this cannot 
be arranged they should be rigidly connected to them or else addi- 
tional longitudinals fitted. 

Circulating pumps, generating sets, and other auxiliaries should 
be securely bolted to foundations that are strongly built of plates 
and angles. 

Deck Erections. — For the usual cargo steamer the deck erections 
above the weather deck consist of a forecastle forward, bridge 
amidships, and poop aft, thus giving what is commonly called 
"three islands." The ship's frames may extend through the deck 
and serve as the vertical stiffeners for the side plating, and to them 

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278 HULL CONSTRUCTION 

may be bracketed beams over which there may be a light steel deck 
with a wood deck on top, or simply tie plates with a wood deck. 

There has been a general tendency to increase the length of the 
bridge house in the three-island type, but there are two conflicting 
considerations to fixing the extent of the deck erections, more 
especially in British-owned vessels. These are freeboard on the 
one hand and tonnage measurement on the other. An increase in 
substantially constructed and efficiently protected deck erections on 
a vessel of full scantlings permits of a reduction of freeboard and 
therefore of an increase in weight of cargo carried. But if these 
deck erections are permanently closed-in spaces, they must be 
measured for tonnage and therefore dues based upon tonnage 
must be paid on them. 

A typical freight steamer as outlined in the table on page 311, 
with the machinery amidships, has a forecastle forward for the crew, 
then a house amidships with quarters for the engineers, and a poop 
aft for stores or for cargo. In some with the machinery aft and 
of the three-island type, the crew is forward, then in the center 
house or island are the officers' quarters while away aft over the 
machinery are the engineers and firemen. In passenger steamers 
carrying one class the passengers are amidships, while in those with 
three classes, the steerage are forward, the first class amidships, 
and the second aft. Here the crew are forward while the officers 
and engineers are partly divided with quarters amidships and aft. 

Deck houses that are away from the sides of the vessel have 
vertical stiffeners with bracket plates riveted to the deck, while 
at the top are other brackets which are riveted to the deck house 
beams. These beams are connected by tie plates over which a 
light wooden deck is laid. 

Cementing. — The entire bottom' of a vessel up to the turn of 
bilges, and the forward and after trimming tanks should be covered 
with the best quality Portland cement — except in oil tankers where 
the cement may be omitted in the oil compartments. In the after 
trimming tank and in other places where a considerable depth of 
cement is required, a thin coating of neat cement is applied to the 
metal, then cork, coke or other light material is put over it, and 
cement poured on top until the whole mass is solid. Drinking 
water tanks should have three washes of neat Portland cement. 

The American Bureau of Shipping Rules state: "The inside of 
all vessels from the keel to the turn of the bilge to be coated with 
approved hydraulic cement. If a mixture of Portland cement and 

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PAINTING 279 

Sand is used the cement and sand should be mixed in about equal 
proportions. The sand should be sharp dry river sand — salt water 
sand must not be used. At middle line the cement should be laid 
sufficiently thick to form a level surface right fore and aft flush 
with the lower side of the limber holes. From middle line to 
bilges the cement must cover all the rivet heads on flange or frames 
and on inside strake butt straps, being correspondingly thicker 
on the outside strakes of skin plating. Vessels fitted with a double 
bottom should have a thin coating of cement laid on the upper 
side of inner bottom plating. It is recommended to coat the floor 
plates with a cement wash in lieu of paint." Lloyd's requirements 
are similar to the above. Before applying the cement all mill 
scale and dirt must be removed from the plates. 

Painting. — All steelwork to be painted must first be carefully 
scraped, scaled and cleaned. Care should be taken that no paint 
is applied to steel which is to be covered with Portland cement. 
The entire structure except as just noted should have a priming 
coat of red lead. After this is dry all rivet heads and flush seams 
and butts, and in general all exposed flush surfaces should be 
smoothed as necessary with an approved rivet cement. 

The outer surface of the hull may be divided into three parts: 
(1) the under water portion, (2) the part that is under water when 
the vessel is loaded and out when she is light called the boot top, 
and (3) the top which is exposed to the weather only. The under 
water portion should be painted with anti-corrosive and anti- 
fouling paints, the boot top with a special paint that is not affected 
by the weather or water, and the top sides with a weather paint. 

The hull of the vessel inside and out, steel decks, bulkheads and 
steel structures, that will be ceiled or covered with wood, should 
be given two good coats of red lead, the priming coat mentioned 
above being considered the first coat. These two coats of red lead 
are in addition to the finishing coats. In some vessels, compart- 
ments finished in red lead only shall be given at least three coats 
in all. Areas finished in white or spar color should have at least 
two coats of the color in addition to the red lead. 

Before launching the underwater body, including the rudder, 
to a suitable distance above the load water line should be given 
one coat of anti-corrosive paint. 

There are a variety of anti-fouling and anti-corrosive paints 
on the market, a few of which are mentioned below. The Am. 
Veneziani Paint Co., New York, N. Y., make a red anti-corrosive 

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280 HULL CONSTRUCTION 

paint that also protects the steel plates from galvanic action. On 
top of this is applied Lamoravia green anti-fouling composition 
(made by the same company) which has a grease base. This green 
composition is sold in a solid mass and must be heated in a boiler 
or kettle to a temperature of 180 degs. F. before it can be applied. 
When melted it is easily applied with brushes like any oil paint. 
One gallon of the anti-corrosive paint will cover about 28 sq. yds., 
and one gallon of the anti-fouling composition about 6 sq. yds. 

Another anti-corrosive and anti-fouling paint for steel vessels 
is the International, the makers (Holzapfels Am. Comp. Co., New 
York) claiming that it dries quickly and resists the corrosive action 
of salt and fresh water. 

A plastic paint, trade name Tockolith, is made by Toch Bros., 
New York. After the hull has been scraped and well cleaned, 
Tockolith is applied; it strongly resists the corrosive effects of salt 
water and abrasion by floating objects which the hull may come in 
contact with. When this is dry an anti-fouling paint consisting 
of copper and mercury is applied which prevents fouling by bar- 
nacles, grass, and other marine growths. For the area that is alter- 
nately exposed to the water and to the air, a special or boot topping 
paint may be put on. This, as made by Toch Bros., is a black, 
waterproof material which retains its color and body, and does not 
flake or peel off. 

Attention should be called to Bitumastic enamel (American Bitu- 
mastic Enamels Co., New York) that is particularly adapted for 
interior surfaces as in pontoons of floating docks and of double 
bottoms of ships, as it can withstand the presence of oxygen and 
water without deterioration. Bitumastic enamel is a solidified 
bituminous composition applied hot to any thickness desired, 
forming a bright black coating that hardens quickly. The surface 
to be coated is first thoroughly cleaned and then given a p rimin g 
coat of Bitumastic solution applied cold which is allowed to dry 
from 12 to 24 hours. Then Bitumastic enamel is applied, it being 
heated to about 380° F., and brushed on while in the molten state. 

Owing to its exceptionally adhesive and penetrating nature, the 
priming coat forms an intimate bond with the steel, and the base 
of the two coatings being identical, they combine, the result being 
a hard, heavy and elastic coating which is absolutely impervious 
and practically indestructible. 

On many ships Bitumastic enamel has been applied to tank 
tops and bilges to a thickness of % in., to double bottoms and peak 

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ENGINE ROOM 281 

tanks ]/% in. on vertical surfaces, and \i in. on shell in double bottom, 
and the engine and boiler seatings covered to the height of the plat- 
forms with a thickness of % to \i in. 

The bottoms of wood vessels are often painted with copper paint. 
One maker (Holzapfels) claims that his paint is a reliable substitute 
for copper sheathing, and for a long time protects the wood against 
the ravages of the boring worm, and the surface against the ad- 
hesion of grass, barnacles and mussels. It should be applied with 
clean brushes on a dry and clean surface. Only one coat is re- 
quired, which takes about half an hour to dry, and when it has dried, 
it presents a smooth and enamel-like surface. 

For yachts and motor boats, great care is taken to have a perfectly 
smooth surface before painting, by puttying all holes and seams. 
Then sandpaper to an even surface and apply the first coat of paint, 
as Devoe's metallic copper paint, allowing for brown or red six hours 
to dry before applying the second coat. When using green, the 
first coat must be thoroughly hard before applying the second coat. 
On new work, two coats of copper paint should be used. With 
brown and red copper paint, the best results are obtained by allow- 
ing the second coat 24 hours to dry before launching. When using 
green copper paint never launch immediately after applying the 
second coat, but allow time for it to become thoroughly hard. 

On old boats or on boats whose bottoms are to be repainted they 
should be cleaned as thoroughly as possible with a steel wire brush, 
and when using brown and red copper paint, it may be applied to 
a damp surface if time and place make \t imperative to paint be- 
tween tides, although it is best to wait until the bottom is thoroughly 
dry. When repainting one coat is generally sufficient, but on bot- 
toms where the old paint is pretty well worn off, use two coats. 

When using green copper paint, never apply over old coats of 
brown or red copper paint. Thoroughly scrape or burn off before 
painting, in which case two coats are necessary. In event of green 
copper paint having been previously used and same being in good 
condition, sandpaper with No. 1 sandpaper and finish with one coat 
of green copper paint. 

The lower parts of the engine room bulkheads and a large portion 
of the boiler room are painted red or brown on account of the wear 
and the dirt, while the upper parts may be painted white to improve 
the light. Black is used on the gratings, furnace fronts and various 
metal parts. 

See also Interior Decoration and Painting of Pipes. 

Digitized by LiOOQ IC 



282 HULL CONSTRUCTION 

WOOD VESSELS 

In the coastwise trade in the United States, wood schooners are 
largely employed, and for harbor service, wood lighters, tugs, ferry- 
boats and excursion steamers. The displacement is usually calculated 
to the outside planking, and the mold loft lines given to the inside. 

Motor boats and other small craft with rounded bilges have 
steam bent frames, while those with V cross sections have a straight 
piece to the bilge and another vertical to it. 

In tugs, lighters, schooners, and barges the frames are of several 
pieces, that are bolted or treenailed together. All butts of timbers 
must be close and not less than \i of their molding. Heads and 
heels of the timbers should be square. The frames may be of all 
one material as oak, although some vessels have mixed frames, that 
is one piece of oak and the next one of chestnut. For the curved 
parts as at the bilge, pieces are selected that can be trimmed, when 
in place, to the lines of the vessel. The sizes and spacing of the 
frames are given in the rules of the American Bureau of Shipping. 

The keels are of oak into which is rabbeted the planking. The 
planking is of long leaf yellow pine or oak, and at the bilge both the 
ceiling (inside planking) and the outside planking are increased in 
thickness. Salting is recommended while building. Salt stops 
must be fitted in all salted vessels just above the air strakes and at 
the turn of the bilge. The use, however, of salt as a preservative is 
rapidly giving place to creosote and carbolineums. All vessels must 
have proper air strakes or air holes below the two upper strakes of 
clamps under all decks. .The planking is caulked with oakum and 
cotton, and thus made watertight. 

All vessels over iooo tons whose length exceeds ten times their 
depth, must be diagonally strapped with iron plates of suitable 
width and thickness on the outside of the frames. The straps 
should be placed at an angle of 45° and extend from the covering 
to the heads of the floor timbers. Four at least of these diagonals 
should cross one another on each side in the body of the vessel. 
These straps should be riveted together where crossed and should 
be let into the timbers and fastened to every frame by two bolts; 
the upper end should be connected to a horizontal strap passing 
around the hull. 

The beams are in a single piece connected to the frames or to 
the inside planking by wood knees. At the center they are sup- 
ported by a row of wood pillars, or if the span is excessive there 
are two or more rows as may be required by the rules. 



ioogle 



WOOD VESSELS 



283 




Figure 47. — Midship Section of Four Mast Schooner. 



Some large schooners and barges are built with two complete 
decks, while others only have one, in which case if the depth in the 
clear from the keelson to the deck beam exceeds 13 ft., then hold 
beams must be installed. 

Vessels for carrying lumber have bow ports, one on each side, 
through which the lumber is loaded and discharged. There are no 
cross bulkheads, thus giving a long hold. For carrying coal the 
arrangement is different, there being transverse bulkheads and 
large deck hatches through which the coal is loaded and discharged. 

The maximum size of a wood schooner does not exceed as a rule 
3,000 tons deadweight, for above this the stiffening required to get 



y Google 



284 



HULL CONSTRUCTION 



the necessary structural strength is excessive when compared to 
the additional carrying capacity secured. As to barges for carrying 
coal a fair average for those along the Atlantic. Coast, that are 
towed as from Norfolk, Va., to Boston, Mass., is about 1,800 tons 
deadweight, a single tug towing 3 of these barges at a speed of 
about 7 knots an hour. 
See tables of Schooners, Tugs, Lighters and Motor Boats. 

CARPENTER AND JOINER WORK AND INTERIOR 
DECORATION 

Carpenter work may be said to include the laying of wooden 
decks, installing the ceiling and cargo battens in the holds, fitting 
masts and spars, bitts, chocks, cleats, etc. Under the heading 
Joiner Work is included the building of cabins and fine cabinet 
work in mahogany or other expensive wood. 

For data on Woods, see Shipbuilding Materials. 

For feet board measure, see page 9. 

Deck Planking. — The weather decks are usually covered with 
yellow pine or white pine planking. The butts should be carefully 
arranged so that there are at least three clear shifts between every 
two butts in the same beam space. When the planks are 6 ins. 
or under in width a single through bolt through every beam is suffi- 
cient; when they are above 6 ins. and not exceeding 8 ins. there must 
be two bolts in every plank one of which may be a short screw bolt, 
while planks exceeding 8 ins. must have two or more through bolts. 
The bolts must be properly sunk into the wood, and their heads 

Number op Deck Bolts per 1,000 Feet Board Measure of 

Planking 

Planks 26 ft. long 



Thick- 






Spacing of Frames in 


Inches 






Weight of 
100 Bolts 


ness of 




















Plank, 






















Inches 


18 


20 


22 


24 


26 


28 


30 


32 


HIn. 


Hln. 


V4 


2980 


2712 


2492 


2312 


2160 


2024 


1912 


1812 






2 


2235 


2034 


1869 


1734 


1620 


1518 


1434 


1359 


22.60 


39.40 


2H 


1785 


1628 


1495 


1385 


1295 


1215 


1145 


1086 


25.48 


43.60 


3 


1490 


1356 


1246 


1156 


1080 


1012 


956 


906 


28.92 


48.00 


3H 


1275 


1162 


1067 


990 


924 


867 


818 


775 


32.10 


52.80 


4 


1118 


1017 


934 


867 


810 


759 


717 


679 


34.75 


57.00 


4M 


994 


904 


831 


771 


720 


675 


637 


604 


39.40 


61.40 


5 


893 


814 


748 


693 


648 


608 


573 


543 


40.50 


65.55 



Thus for a plank 3 ins. thick by 6 ins. wide with a beam (frame) spacing of 24 ins., 
the number of bolts will be -~— * 193 per 1000 feet beard measure. 



y Google 



CABIN AND STATEROOM BULKHEADS 285 

covered with wood plugs of the same material as the deck planks, 
imbedded in white lead. The seams between the planks must be 
well caulked with oakum and payed with pitch or marine glue. 

The margin plank, that is the one next to the waterway, is 8 to 
12 ins. wide, and into it are nibbed at the ends the narrower widths 
of planking. The planks around the deck house and skylights are 
increased in width to 6 to 8 ins. Under the winches, windlasses, 
capstans, etc., the planking is increased in thickness so as to be 
1 or 2 ins. above the deck. 

Cargo battens, often referred to as open sparring or spar ceiling, 
are fastened to the reverse frames to prevent cargo from injury 
by coming in contact with the sharp edges of the reverse frames. 
Lloyd's requires all vessels to have cargo battens in the holds except 
those carrying coal, ore, oil, and wood. See Loading and Stowing 
of Cargoes. The battens are usually pine planks about 2 ins. thick, 
6 to 9 ins. wide and spaced 9 to 12 ins. apart. They may be bolted 
to every third or fourth reverse frame, or they may be held in 
place by cleats fastened to the frames, in which case they are port- 
able. Bulkhead stiffeners having sharp corners should be covered 
with battens about 1J^ ins. thick. 

Ceiling. — On the tank top of cargo steamers the ceiling, often 
spruce or yellow pine, may be omitted except under the hatches and 
at the bilges. If the ceiling is omitted under the hatches' the tank 
top plating must be increased .08 in. in thickness in way of the 
hatchways. Vessels not having double bottoms are to be ceiled, 
the thickness varying from 2-inch pine planking in small vessels 
to 2 J^ in large, by about 10 ins. wide, arranged in portable sections 
approximately 9 ft. long that can be readily handled. The ceiling 
must not be fastened through the tank top. 

Hatch covers are of spruce or yellow pine, made in sections about 
24 ins. wide, and provided with lifting rings. Lloyd's states: "All 
hatches to be solid (or gratings of sufficient strength) and not less 
than 2J^ ins. thick in hatchways not exceeding 16 ft. in breadth, 
when this is exceeded they are to be not less than 3 ins. where fore 
and afters are fitted. Efficient supports are to be provided having 
at least 19£-inch bearing for the ends of the hatches. Where no 
fore and afters are fitted, hatches to be not less than 3 ins. and 
supports have not less than 3 ins. bearing for the ends of the hatches 
at the end coamings. 7 ' 

Cabin and Stateroom Bulkheads. — Bulkheads forming passage- 
ways are built with vertical frames which are covered on the outside 

Digitized by VjiOOQ 1C 



286 



HULL CONSTRUCTION 




Dome /Toof 




S/o/>//y ftoof 



QIQQ 



F/at ftoof 




1 




Compan/o/? IVay 

Figure 48. — Skylights and Companion Way. 

Digitized by VJiOOQLC 



• SKYLIGHTS 287 

with panels of polished hard wood or pine enameled white and on 
the inside with panels or tongue and groove boards. To provide 
for a free passage of air the upper part of the bulkhead between the 
beams may consist of an ornamental metal grating. The partitions 
between the staterooms may be of double tongue and groove board- 
ing about % in. thick in two courses at right angles. The doors 
to the staterooms are 2 ft. 6 ins. to 3 ft. wide. 

Skylights. — Different types are shown in Fig. 48.* The dome 
roof over the main cabin saloon and social halls on passenger steam- 
ers makes a good appearance. The sloping roof is fitted over engine 
rooms and may be built of steel plates and angles instead of wood. 
Companionways are of steel, teak, or mahogany. For motor 
boats and fine yachts the skylights, companionways, and deck 
houses are of mahogany or teak. 

Miscellaneous Notes. — Thwartship flights of stairs should be 
avoided as much as possible, for in descending a person has to meet 
the rolling of the vessel. In laying out stairs, take the sum of 
two risers from 24 ins. and the remainder will be the required tread. 

Berths in passenger quarters are of metal, about 30 ins. wide 
and approximately 36 ins. between the upper and lower one. In 
cabins de luxe are beds as on shore. In crew's quarters pipe berths 
may be installed about 2 ft. 3 ins. wide by 6 ft. 3 ins. long, the 
bottom of the first berth being 10 ins. from the floor and of the 
second 46 ins. from the floor. The U. S. Steamboat-Inspection 
Rules state that berths can only be two high. 

The height of a chair seat or seats along the side of an excursion 
steamer varies from 17 ^ to 18 ins. above the deck. Depth of seat 
15 to 16 ins. 

Writing and dining tables are 2 ft. 5 ins. high. Mess tables 
and benches are of white ash. 

Interior decoration and painting should be governed by the trade 
and climate. If the vessel is to run in the tropics the rooms should 
be light and airy and finished off in white; if in cold regions then 
dark woods and the reverse of the treatment for the tropics should 
be followed. 

Staterooms are invariably finished off in white enamel paint and 
mahogany — and the smoking rooms in oak. If the deck heights 
permit, a ceiling may be built under the beams, thus giving a space 
in which wires and pipes may be run and yet be easily accessible by 
having a few panels portable. 

* From Practical Shipbuilding, A. C. Holmes. 

Digitized by VjOOQiC 



288 HULL CONSTRUCTION 

As a vessel's saloons are seldom high enough for indirect lighting, 
wall brackets are necessary. The lighting of a saloon at night is 
improved if lights are placed around the skylight, otherwise the 
skylight makes a black patch and puts the middle of the room in 
shadow. 

New wood, particularly on outside work, as deck houses, hatches, 
spars, etc., should first have a coat of a wood primer. Open- 
grained woods, as oak, ash, chestnut, mahogany, and walnut, should 
then be filled with a wood filler. After the filler is dry (24 hours) 
it should be sandpapered with the grain of the wood to a smooth 
surface. Close-grained woods, as cherry, birch, white wood, and 
maple, should have a coat of primer but the filler may be omitted. 
On interior work it is not necessary to use both primer and filler, 
the primer alone on close-grained woods or the filler alone on open- 
grained being sufficient. After the primer and filler or either 
alone have been applied, and the surface is dry, it is then ready 
for varnishing. Painting and varnishing should not be done on 
a damp or cold day. One gallon of varnish will cover about 500 
sq. ft. for the first coat and about 600 sq. ft. for the second. 

Ceilings, furring strips, battens and the faying surfaces of wood 
decking should be well painted; the wood to be painted on all 
sides except for decks and such work as is to be finished bright. 

Below are abstracts from the specifications of a steamer for the 
U. S. Coast Survey. "Areas finished in white or apar color shall 
have at least two coats of the color in addition to the red lead 
specified. Soft woods, in furniture details and the like will have a 
coat of white shellac and where painted shall have at least three 
coats of oil paint. Wood work to be bright shall be filled, shellacked, 
varnished and rubbed down to a dull finish. In all cases each coat 
of paint or varnish must be dry and hard before the next coat is 
put on. 

"Cork paint shall be applied to interior surface of outside plating 
and to frames in living quarters, storerooms and holds. 

"A wash strake 4 ins. high shall be painted around the bottom 
of all steel and wood bulkheads in living quarters and passages, the 
color to match the color of the deck surface in the respective com- 
partments. 

"All piping whether bare or covered shall be painted to match 
the compartment in which it runs. 

"Galvanized work may be painted with aluminum paint, as also 

watertight door dogs, grab rods, and steam radiators in the crew's 

quarters, while the radiators in the officers' will be finished in gilt. 

o 



MEASURING SCREWS 



289 



"The waterways on the upper deck and the exposed upper deck 
plating way forward shall be painted buff, as also the canvas cov- 
ered deck forming the top of the deck house. Linoleum shall not 
be painted but shall be thoroughly cleaned and heavily waxed. 
If directed it may be shellacked." 

Cork paint is not used in holds of merchant ships as it is too expen- 
sive, but is used in the living quarters. 

Measuring Screws. — Flat head wooden screws are measured over 
all, round head from under the head, and oval head from the edge 
of the bevel. Lag screws have square heads and are measured from 
under the head. Machine screws, fillister and round heads, are 
measured from under the head, flat heads over all, and oval heads 
from the edge of the bevel. 

Lag Screws 
Square heads, cone or gimlet points. Gimlet point screws only 
supplied from 5 /ie in. to J£ in. dia. inclusive. 



Diameter of Screw (Inches) 


Approx- 
imate 






















Length 


M*A 


% 


i 7 » 


a 


&*% 


H 


H 


1 


IX 


VA 


of 
Thread 


Length under Head to Extreme Point (Inches) 


Diam- 
eters 


IX 


VA 


VA 


VA 














.* To head 


2 


2 


2 


2 


2 












VA 


2H 


2H 


2H 


2A 


2A 


2X 










2 


3 


3 


3 


3 


3 


3 


3 








2\i 


3H 


3^ 


3H 


SX 


3^ 


3A 


SX 


3A 






2X 


4 


4 


4 


4 


4 


4 


4 


4 






3 


4^ 


VA 


4H 


VA 


VA 


VA 


VA 


VA 






3X 


5 


5 


5 


5 


5 


&A 


5 


5 


5 




4 


5H 


VA 


5H 


VA 


VA 


VA 


VA 


VA 




4 


6 


6 


6 


6 


6 


6 


6 


6 


6 


6 


VA 






M 


6H 


QX 


VA 


VA 


VA 


QA 


VA 


; b 






7 


7 


7 


7 


7 


7 


7 


7 


5 






7A 


7H 


7X 


7X 


7X 


7X 


7A 


7H 


; e 






8 


8 


8 


8 


8 


8 


8 


8 


6 






9 


9 


9 


9 


9 


9 


9 


9 


6 








10 


10 


10 


10 


10 


10 


10 


7 « 








11 


11 


11 


11 


11 


11 


11 


7 








12 


12 


12 


12 


12 


12 


12 


7 


Threads Per Inch 




10 


7 


7 


6 


5 


VA 


4M 


3 


3 


3 




Size of Heads (Inches) 




% i* 


A 


n 


*A 


n is 


VA 


1t b « 


VA 


ltt 


y/ 


• Wi %Ip 


A U 


h 


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% 


31 S3 


i 9 « 


U 


% 


11 


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Google 



Weight of Lag Screws per 100 



Length 
Under 




Diameter 










Head 














to Ex- 














treme 


























Point 


A 


H 


i 7 * 


H 


A 


% 


X 


% 


1 


IK 


1M 


IX 




lb. 


lb. 


lb. 


lb. 


lb. 


lb. 


lb. 


lb. 


lb. 


lb. 


lb. 


lb. 


VA 


4.2 


6.5 


9.2 


13.0 


















IH 


4.7 


7.1 


10.0 


13.8 


















2 


5.2 


7.7 


10.9 


14.0 


23.0 


24.8 














2X 


5.7 


8.4 


11.8 


16.1 


24.5 


27.3 














2H 


6.2 


9.2 


12.7 


17.4 


26.0 


29.0 


43.0 












3 


7.2 


10.6 


14.6 


•19.0 


29.2 


32.9 


48.3 


75.0 










3M 


8.2 


12.0 


16.6 


21.5 


32.5 


36.9 


53.8 


78.5 


90 








4 


9.2 


13.5 


18.8 


24.0 


35 .9 


41.0 


59.6 


82.0 


99 








4H 


10.2 


15.0 


20.7 


26.5 


39.3 


44.9 


65.5 


86.0 


108 








5 


11.3 


16.5 


22.8 


29.0 


42.7 


48.8 


71.5 


90.0 


118 


i50 






5X 


12.4 


18.0 


24.9 


31.5 


46.1 


52.7 


77.5 


98.0 


128 


163 






6 


13.5 


19.5 


27.0 


34.0 


49.5 


56.6 


83.5 


106.0 


138 


176 


240 




7 






31.1 


39.0 


56.3 


64.5 


95.5 


122.5 


158 


203 


270 




8 






35.2 


44.0 


63.1 


72.5 


107.6 


139.0 


178 


230 


300 


420 


9 








49.0 


69.9 


80.5 


119.8 


155.6 


198 


257 


332 


468 


10 








54.0 


76.7 


88.5 


131.0 


172.0 


219 


284 


365 


516 


11 










83 .5 


96.5 


143.1 


188.5 


240 


311 


395 


564 


12 










90.5 


104.5 


155.4 


205.0 


261 


338 


425 


612 


13 












112.5 


167.6 


221.5 


282 


365 


459 


660 


14 












121.0 


179.8 


238.0 


304 


393 


493 


710 


15 












129.5 


192.0 


255.0 


326 


421 


527 


760 


16 












138.0 


204.0 


272.0 


348 


449 


562 


810 



Number of Lag Screws in 250-lb. Keg 
(Approximate) 



Length 
Under 






Diameter 






Head to 












Extreme 












Point 


i 8 « 


*A 


X 


% 


X 


IX 


5700 


3700 








2 


4600 


3300 


1600 


1000 




2A 


3600 


2800 


1400 


900 


500 


3 


3000 


2500 


1300 


800 


450 


3X 


2600 


2300 


1200 


700 


425 


4 


2300 


1900 


1000 


625 


375 


4K 


2000 


1700 


850 


550 


325 


5 


1800 


1500 


700 


500 


300 


5H 


1600 


1400 


650 


450 


275 


6 


1400 


1250 


600 


375 


250 


7 




1100 


550 


325 


225 


8 




1000 


475 


270 


200 



292 



Google 



LAG SCREW TESTS 



293 



Lao Screw Tests 
Screws drawn out of yellow pine 



Diameter of Screw . 
Wood (deep) inches 
Drew out (lb.) 




Standard Steel Wire Nails* 
Sizes, Lengths, and Approximate Number per Pound 



Sises 



Length 
(Inches) 



Common 



Diameter 



B. W. G. 



Inch 



No. Per 
Pound 



2d 

3d Com 

4d 

6d 

6d 

7d 

8d 

9d 

lOd 

12d 

16d 

20d 

30d 

40d 

50d 

60d 



.072 
.083 
.102 
.102 
.115 
.115 
.124 
.124 
.148 
.148 
.165 
.203 
.220 
.238 
.259 
.284 



900 
615 
322 
250 
200 
154 
106 

85 

74 

57 

46 

29 

23 

17 

13^ 

10h 



* Common nails have flat heads and may be barbed or smooth. Brads have 
small circular heads and come in the same mses as common nails. There is little 
difference in the weight of a common nail and a brad. 



Square Boat Spikes 
Approximate Number in a Keg of 200 Pounds 



Sise 


Length of Spike (Inches) 


(Ins.) 




























3 


4 


5 


6 


7 


8 


9 


10 


11 


12 


14 


16 


M 


3000 


2375 


2050 


1825 


















A 


1660 


1360 


1230 


1175 


990 


880 














H 


1320 


1140 


940 


800 


650 


600 


525 


475 










A 






. . . 


600 


590 


510 


400 


360 


320 


230 






8 




. . . 




450 


375 


335 


300 


275 


260 


240 














... 


260 


240 


220 


205 


190 


175 


160 



11 



Co ogle 



294 HULL CONSTRUCTION 

STRUCTURAL STRENGTH 

As to proportions of vessels for strength, Lloyd's Rules state: 
"All vessels exceeding 14 lengths in depths to have special stiffen- 
ing which must be approved by the Committee, and all exceeding 
13J^ depths must have a bridge extending over the midship half 
length of the vessel or such special compensation for extreme pro- 
portions as may be required by the Committee." 

The American Bureau of Shipping Rules state: "Their rules 
apply only to steam vessels the length of which does not exceed 11 
times their depth and to sailing vessels the length of which does 
not exceed ten times their depth. Vessels whose length to depth 
exceed these proportions must have their scantlings augmented 
and additional strengthening fitted." 

For ordinary vessels of standard proportions built according to 
Lloyd's, the American Bureau of Shipping, or other recognized so- 
ciety, usually no strength calculations are made, but they are made 
for commercial craft of exceptional proportions, and for warships. 
Below are outlined strength calculations and the curves that can 
be plotted for them. 

Curve of Weights.* — Divide the length of the vessel into a number 
of equal parts, and calculate the weight of the materials for one foot 
of length. These weights per foot are then set off from the base 
line on their respective ordinates and the points joined together, 
forming a jagged line which represents the hull weights. 

Next calculate the weights of the cargo, coal, engines and boilers, 
and stores — and if a warship, of the guns and armor — which can 
be added as rectangles to the curve of hull weights. The machinery 
calculations can be divided as follows: 

(1) Boilers. — Everything connected with the boilers as uptakes, 
funnels, pumps, etc., to be uniformly distributed over the length of 
the boilers. 

(2) Engines. — Everything connected with the engines as con- 
densers, pumps, etc., all being assumed to be uniformly distributed 
over the length of the bed plate. 

(3) Shafting. — Weights are taken from the forward end of the 
thrust to the after end of the propeller shaft, and assumed to be 
distributed over this length. The weight of the bearings is to be 
included. 

(4) Propeller. — The weight is assumed to be uniformly distributed 
over the length of the propeller boss. 

♦Abstracts from Ship Cal. and Cons., G. Nicola. 



Digitized 



by Google 



CURVES OF AN OIL TANKER 



295 



T^Tu^s 




8.9 « * 



J? s 



E 



si 5 

fa" a I 



Eg - 

. I 
111 

Mi* 



-1 -a 

l!l 
j 



II 
« i 

si 



S*tf*i/fJ* 9/&*S 



J***/ Jt/ffJoSct * 



*.1 



II 






Digiti 



zed by G00gk 



296 HULL CONSTRUCTION 

A curve including both the hull and machinery weights, and if 
a warship the guns and armor, can be plotted, the area of which is 
equal to the displacement of the vessel, and the center of gravity 
of this new curve should come over the center of buoyancy. 

Curve of Buoyancy. — The above curve gives the weight per foot 
of a vessel and to find the support given it by the water, a curve 
of buoyancy is plotted. To do so, the displacement in tons per foot 
of length is calculated by finding the area of each section in square 
feet (the sections are preferably taken at the same intervals as 
selected when the calculation for the curve of weights was made), 
multiplying by 1, as a section is assumed as 1 ft. in length, and di- 
viding the product by 35, to get the buoyancy in tons per foot 
of length in salt water. These quantities are laid off at the same 
intervals as selected for the curve of weights, and a curve through 
the points is known as the curve of buoyancy, the area of which 
should equal the displacement of the ship. 

By examining the curve of buoyancy in conjunction with that 
of the curve of weights, the portion of the vessel where the weights 
exceed the supporting pressure due to the buoyancy of the water 
may be noted. 

Curve of Loads. — By measuring the difference between the 
ordinates of the curves of weights and buoyancy, and laying them 
off on the same intervals, a curve of loads is obtained. Having this 
curve, a ship may be considered as a beam and the calculations 
pertaining to shearing and bending be made. For instance, suppose 
a vessel is supported at the bow and stern by a wave, leaving the 
middle portion unsupported. This is a case of a beam supported 
at the ends with a uniformly distributed load, if the weight per foot 
of length of the cargo and machinery space is the same. Or should 
the vessel be light and the machinery be amidships, this would be 
a case of a beam supported at the ends and loaded in the middle. 
Similarly a vessel may be supported at the middle by a wave, the 
weights at the ends tending to cause her to hog. 

- Thus by the formula •*- = -j the stress on any portion of the hull 

may be obtained, but before using this formula there must be 
found: (1) the position of the neutral axis which passes through 
the center of gravity of the section; and (2) the moment of inertia 
of the section about the neutral axis. 

Two calculations are necessary, one for the section under a hog- 
ging moment and the other under a sagging. In each case the posi- 

Digitized by vjOOQ 1C 



CURVE OF LOADS 



297 



tion of the neutral axis and moment of inertia of the section will be 
different. 

As to the stresses in the materials in both instances, that above 
the neutral axis will be subjected to a different one than below. 
For materials in tension, allowance must be made for lightening 
and rivet holes, but in compression this is not necessary. Wood is 
commonly taken as being equivalent to ^ its area in steel for ten- 
sion and compression, while armor is considered to be of no value 
in tension, but is in compression. 

Neutral Axis and Moment of Inertia Calculations. — Take a plan 
of the midship section of a vessel with all the scantlings on it and 
draw a horizontal line one-half the depth of the section, assuming 
this line as the temporary neutral axis. Lay off a table as below, 
the areas being in square inches and the distance their center of 
gravities are from the assumed neutral axis in ft. 



1 

Items 


2 

Scant- 
lings 
in Ins. 


3 

Effective 
Area in 
Sq. Ins. 


4 

Lever 
in 
Ft. 


5 

Moment 


6 

Lever 
in 
Ft. 


7 

Moment 

of 

Inertia 


8 

A A 

X A» 






















A 




M 




J 


% 



In Column 5 some of the items are above the neutral axis and 
others below, hence the algebraic sum M of this column is divided 
by A, the sum of the effective areas, the quotient being the distance 
in feet the real neutral axis is from the assumed. 

The levers in feet in Column 6 are the same as those in 4, and 
by multiplying these levers by the moments in Column 5, there is 
obtained the areas times the square of their distances from the as- 
sumed neutral axis, which are positive quantities, their sum being 
designated by 7. 

For the portions of the sections which are vertical as the strakes 
of shell plating at the water line, an addition is required for the 
moment of inertia of the items about axis through their own cen- 
ters of gravity, which is given by the formula ^i X h*. For por- 
tions of the sections which are horizontal as in the deck plating, 
where h is small, the additions may be neglected. 



Digitized 



by Google 



298 HULL CONSTRUCTION 

Thus the moment of inertia about the assumed neutral axis is 
I a = / + h ana " to transfer this moment to the true neutral axis, 
from I a subtract the product of the effective areas A times the 
square of the distance d } the real neutral axis as found above is 
from the assumed neutral axis. Therefore the real moment of 
inertia = I a — A X <P. 

Knowing, then, the location of the neutral axis and the moment 

of inertia, by applying the formula — = t there can be calcu- 

V * 
lated the stress on the material farthest from it. 

Example. Steamer 350 ft. long, 60 ft. 4 ins. beam, 28 ft. molded depth, load 
displacement 9600 tons, draft 23 ft. 9 ins., neutral axis above base 12 . 82 ft., distance 
(y) top of section from neutral axis 23.18 ft., moment of inertia about neutral 
axis 285442. 

The maximum bending moment on a wave crest is usually taken as ^ of the 
displacement times the length, thus in the above steamer the maximum bending 

moment M is 96 °° * 35 ° ' = 96000 foot-tons. 

oo 

Using the formula —- = y, where the greatest stress p in tons per square inch 

M. £6000 g^ 
under a hogging strain = / = 28544 2 « to ■■ 7.79 tons per square inch. 
V "23TI8 12314 

Stresses as just given vary in different vessels, for in large ones 
a stress of 10 tons per square inch is considered safe on a standard 
wave length, that is, one supporting the bow and stern, for such a 
Wave would doubtless never be encountered, while ships of 300 and 
400 ft. have stresses of 6 to 7 tons. 

For hogging as in the above the full area below the neutral axis 
is taken, and often A the full area above the axis to allow for rivet 
holes. 

To obtain the greatest stress under a sagging. strain, a new 
moment of inertia calculation is necessary, otherwise the work is 
the same. For sagging the full area above the axis is' taken, and 
A the full area below the axis to allow for rivet holes. 

Curve of Shearing Stresses. — Calculate the area of the curve of 
loads from the forward end, and at each interval (using the same 
intervals as when making the calculations for the curve of weights), 
set off the areas and draw a line through the points. The result- 
ing curve is the curve of shearing stresses. From it the shearing 
force at any point in the length of a vessel may be expressed as the 
algebraic sum of all the stresses caused by the excess of weight 
or buoyancy from either end. 

Digitized by VjOOQ LC 



CURVE OF BENDING MOMENTS 299 

The shearing force in a ship amidships is usually zero, and is at 
a maximum about a quarter the length from each end. This in 
large ships calls for extra riveting, for Lloyd's Rules state: "In 
vessels of 480 ft. and upwards, the landing edges are to be treble 
riveted for one-fourth the vessel's length in the fore and after 
bodies for a depth of one-third* the depth." 

Curve of Bending Moments. — This is obtained from one of shear- 
ing stresses by taking the area from the forward end to any given 
ordinate and laying this area off perpendicular to the base line. 
A curve through the points gives the curve of bending moments. 
The bending moment at any point in the length of a vessel may be 
expressed as the algebraic sum of all the shearing stresses from 
either end. 

The maximum bending moment may be approximately found by 

multiplying the displacement D by ^ to Jg of the length L of 

D V Li 
the ship, thus — ~= — . See example above. 

The minimum tension per square inch on the sheer strake equals 
maximum bending moment X distance neutral axis below sheer strake 
total moment of inertia 

In all the above calculations the ship is assumed to be in still 
water, but as this is seldom the case, the curves do not represent 
the true stresses as experienced when in a seaway where there 
is a continuous changing of excess weight over buoyancy. Hence 
ample factors of safety must be allowed. 

Transverse Section. — As a vessel may be taken as a beam and 
calculations as outlined above made on her strength, the form of 
transverse or cross section is important. The average vessel may 
be assumed to have a rectangular one, and although such a section is 
a strong one, yet by adding a center longitudinal web or bulkhead 
its strength can be greatly increased, the web taking the strains 
to a large extent off the sides or shell plating, and furthermore 
serving as a support to the deck and deck beams. 

Hence the importance of a fore and aft bulkhead, particularly in 
wide and shallow draft vessels, which should not be abruptly 
stopped but continued some distance as a girder with a gradually 
decreasing strength section. In many vessels it is not practical, 
owing to the nature of the cargo to be carried, to have a fore and 
aft bulkhead, and instead a heavy girder is connected to the under 
side of the deck beams, which is supported by widely spaced pillars. 
(See Pillars.) The depth from the tank top to the main deck 

Digitized by VjiOOQ LC 



300 



HULL CONSTRUCTION 



and the distance to the first tier of beams must not exceed a certain 
limit (see Lloyd's, British Corporation, etc.)i for if they do the 
rules require the sizes of the frames and other parts to be increased. 
Submarines are given circular, or nearly so, cross sections, for the 
reason that flat surfaces would require exceptional stiffening to 
prevent them from collapsing. For when a body is submerged in 
water every part of its surface is subjected to an equal pressure, 
viz., top, sides, and bottom, and the strongest form to resist these 
pressures is a circular one. Submarines have sufficient strength 
to sink to a depth of about 100 ft.; some have gone to 175 ft. 



SPECIFICATION HEADINGS 

In preparing the specifications of a vessel it is often of service 
to have a list of the hull, engine, boiler and miscellaneous equip- 
ment that may be required. Below is a list that will serve as 

a guide. . 

Introduction 



Dimensions, class and general 
characteristics of the vessel 

Carrying capacity — passengers 
and freight — speed 

Classification Society 



Payments 

Insurance 

Trial 

Builder's guaranty 



Frames, size pi and spacing 


Hatches 


Web frames 




Stem and stern posts 


Floors 




Rudder 


Beams 




Deck house 


Beam brackets 




Bridges 


Keel 




Masts and rigging 


Keelsons 




Watertight doors 


Side stringers 




Cement 


Inner bottom 




Bollards (bitts) and chocks 


Longitudinals 




Rail and awning stanchions 


Foundations for engines, 


boilers, 


Bulwarks 


pumps, etc. 
Pillars (stanchions) 




Scuppers 
Boat davits 


Shell plating 
Bilge Keel 




Anchor, chain, chain stoppers 
Joiner work—- passengers', crew's 
and officers' quarters 




Cargo ports 




Airports 
Bulkheads 




Cargo battens 




Painting 


Deck plating 







Google 



MACHINERY 



301 



Machinery 



Engines — type, I. H. P. 
Steam 


Hot well 


Evaporator 


Revolutions 


Covering of steam and exhaust 


Number and size of cylinders 


pipes 


Cylinders — liners 


Boilers — type and size of 


Relief valves and drains 


Steam 


Bed plate 


Heating surface and grate 


Columns 


area 


Connecting and piston rods 


Circulators 


Pistons 


Gauges — steam and water 


Water service 


Fittings — safety valve, blow- 


Lubricating system 


off valve, feed water con- 


Valves — piston — slide 


nections, etc. 


Reversing gear 


Grate bars 


Turning gear • 


Covering 


Throttle valve 


Draught — natural or forced 


Separator 


Fans — capacity — turbine or 


Shafting — crank — thrust — line 


steam engine driven. 


Bearings — linings 

Propeller — size — blades bolted 


Uptake and stack 
Boiler feed pumps 


on — material 


Injectors 


Fairwater 


Floor plates in engine and boiler 


Condenser — type 
Sq. ft. of cooling surface 


rooms 


Spare parts for engine, boilers, 


Fittings 


and auxiliary machinery 


Air pumps 


Fuel oil pumps 


Circulating pump 


Superheaters 


Feed water heater 





Systems and Equipment 



Electric 


Ventilating 


Size and type of generating 


Pressure or exhaust 


units 


Fans 


Location , 


Ducts 


Light and power circuits 


Ventilators 


Wiring system — size of wires 




and conduits 


Plumbing 


Switchboard 


Toilets, washstands, bath tubs 


Number of lights, size and 
where located 


Check valves on discharge 
pipes 


Searchlights 
Storage batteries 


Drainage 
Pumps 
Sluice valves 


Heating 


Steam, thermotank or electric 


Strainers 



y Google 



302 



HULL CONSTRUCTION 
Systems and Equipment — Continued 



Fire systems 
Water and steam 
Pumps 
Hose 

Fresh water 
Pumps 
Tanks 

Refrigeration system 

C0 2 , ammonia or dense air 
Insulation 

Ship machinery 
Steering engine 
Capstan 
Windlass 
Winches 

Interior communication 
Signal system between pilot 
house and engine room 

Life boats, rafts and life pre- 
servers. If a U. S. vessel, see 
U. S. Steamboat Inspection 
Rules. 

Carpenter's stores 

Boatswain's stores 

Lights 



If [a U. S. vessel, see 
U. S. Steamboat Inspection 
Rules 

Navigating instruments 

Tarpaulin covers 

Baking outfit 

Galley outfit 

Pantry outfit ' 

Glassware 

Dishes 

Cutlery and plated ware 

Linen 

Bedding 

Flags 

Wireless 

Storm oil 



HULL WEIGHTS 

The difference in finished steel weights of a ship built to Lloyd's, 
Bureau Veritas, and British Corporation Rules is very small. 
For quickly determining the approximate weight of a steel hull 
either of the formulae given below may be used; one is known as 
the cubic and the other as the surface foot. 

Cubic. — Weight of finished steel in hull in lb. = length X breadth 
X depth X coefficient. The coefficient varies from .0036 to 
.0043, the larger coefficient for vessels having the greatest 
ratio of length to depth and breadth to depth. 



ioogle 



WEIGHTS 



303 



Surface Foot — Let d = depth of vessel measured from the 
bottom of the flat plate keel to the uppermost continuous 
. deck. Then surface foot = length X (breadth + 2d). 
The pounds per square foot vary from 97 to 125 and taking 
a mean value of 111, the surface foot found by the formula, 
length X (breadth + 2d) multiplied by 111 will give the 
weight in lb. of the finished steel in a vessel. 
Of the total weight of hull steel, from 70 to 80% is taken up by 
the keel, frames, beams, keelsons, deck and shell plating. The re- 
maining 30 to 20% represents bulkheads, engine foundations, 
masts, etc. 

Percentages of total angles and plates for ordinary vessels of 
about 400 ft. long and .75 coefficient, built to Lloyd's 100 A. I. 
three deck class, with deep framing in lieu of hold beams, and with 
double bottoms, are given in the following table. C is a steamer 
built to British Corporation Rules of the highest class, but other- 
wise similar to A and B. 



Table op Weights* , 






Items 


A 

Steamer 


B 
Steamer 


c 

Steamer 


Main frames and reverses 


Per cent. 

7.5 
2.1 

1.8 
1.7 

4.4 
5.8 
6.9 
3.3 
2.2 
2.4 

10.4 
1.8 
4.8 
1.6 
4.8 

26.8 
3.3 


Per cent. 

7.6 
2.2 
2.0 
1.3 
6.2 
5.8 
6.3 
2.7 
2.2 
1.7 

10.0 
1.7 
4.6 
2.1 
4.2 

26.4 
3.9 


Per cent. 

7.2 


Tank frames and reverses , 


1.5 


Connecting angles, etc., in tank 

Hatches 


1.7 
3.2 


Side keelsons 


3.8 


Main deck plating 


6.2 


Upper deck plating 


6.3 


M ain deck beams 


2.2 


Upper deck beams 


1.8 


Casings ." 


2.4 


Floors and Intercostals 


7.8 


Center longitudinal and margin plate. . 
Tank top .- 


1.7 
3.5 


Tunnel/. 

Bulkheads 


1.9 
3.0 


Shell 


26.6 


Erections 


5.8 







* From A Class Book on Naval Architecture, W. J. Lovett. 



Digiti 



zed by G00gk 



304 



HULL CONSTRUCTION 



Steel Weights of a Steamer* 

430 ft. long, 46 ft. beam, 34 ft. 3 ins. deep, built to Lloyd's 3-deck 

rule. 



Part of Hull 



Keel bars and stem 

Stern post, rudder frame and struts 

Frames, reverse frames and doub- 
lings 

Floors and tail plates 

Beams and carkngs 

Keelsons .' 

Bulkheads (W. T.). 

Bunker casings 

Engine and boiler seats 

Shaft tunnel and stools 

Inner bottom plating 

Shell plating, including bulkhead 
liners 

Stringers and ties 

Deck plating 

Cargo and coal hatches .... 

Engine and boiler casings 

Deck houses 

Sundry deck and hold work .... 

Fresh water tanks 

Slip iron 

Molding and copes 

Rivet heads. 



Finished steel, weight. 



Weight 

in 

Tons 



3.5 
20.0 

275.0 

301.0 

225.4 

142.5 

102.7 

40.0 

25.0 

37.7 

119.4 

734.2 

217.6 

305.3 

37.5 

77.6 

140.0 

25.0 

13.2 

57.0 

46.5 

44.0 



2990.0 



Forcings . 
Angles 
Plates. 
Bulb Tee 

Slips 

Moldings 

Castings 

Rivet heads, 



Summary 

Tons 

6.0 

587.0 

2063.6 



168.4 
57.0 
46.5 
17.5 
44.0 



Total 2990.0 



* From the Naval Constructor, G. Simpson. 

See also table of Merchant Vessels. 



MACHINERY WEIGHTS 

Total weight of machinery (steam engine, boilers, water, etc.) 
is about 448 lb. per i. h. p. for forced draught boilers and 558 lb. 
per i. h. p. for natural draught. 

The i. h. p. per ton of engines, boilers, and water (that is, water 

in boilers) is about 5.5. Thus the machinery weight of a steamer 

460 ft. long, 58 ft. beam and 27 ft. draft, having an engine of 4,000 

4000 
i. h. p. would be -=-=- = 730 tons approximately. 

Digitized by VJiOOQlC ' 



MACHINERY WEIGHTS j 305 

or making a preliminary estimate note the following weights: 

Main engines. 60 lb. per i. h. p. 

Shafting and wheel 40 lb. per i. h. p. 

Condensing equipment 15 lb. per i. h. p. 

Auxiliary machinery 20 lb. per i. h. p. 

Piping 15 lb. per i. h. p. 

Boilers, see following tables, also section on Boilers. 
Total machinery of stern wheelers built to run on the Mississippi 
River (U. S.) weigh from 415 to 560 lb. per i. h. p. 

The sum of the cylinder diameters in feet multiplied by 2.4 to 2.5 
gives an average length of the engine room in feet for a triple 
expansion engine. If all the pumps are independent of the engine 
the above length should be slightly increased. 

The total length of the boiler room with single end Scotch 
boilers and one stokehold is equal to the length of the boilers 
multiplied by about 1.83. When there is a common stokehold for 
boilers arranged fore and aft, it is usual to allow 2 ft. to 2 ft. 6 ins. 
more than for a single stokehold. An approximate figure for the 
total weights in a boiler room in tons may be obtained by multi- 
plying the volume of the boilers in cubic feet by .04 to .05 de- 
pending on whether the boilers have natural or forced draft. 

(From Mar. Eng'g Estimates, C. R. Bruce.) 

Machinery Weights* 



Engine 



I. H. P. 



Boiler 
Press 



Engine 



Weight 
Boilers 



Funnel, 
Mount- 
ing, etc. 



Water 



Total 



Weight 

Per 
I. H. P. 



19 X 30 X 50 


33 
22 X 35 X 57 


42 

24 X 38 X 62 


42 
24 X 39 X 64 


33 
30 X 46 X 75 


45 
31 X 50 X 82 



57 



860 
1383 
1585 
1786 
2600 
2850 



160 
150 
160 
160 
160 
160 



(tons) 
68 

105 

125. 

93 

157 

251 



(tons) 
35.8 

62.5 

64. 

80. 
116.5 
146. 



(tons) 
8.5 

17.6 

20.9 

12.4 

31.4 

42.5 



(tons) 
20.7 

35. 

46. 

52. 

80. 

82.5 



(tons) 
133. 

221. » 

363.9 * 

237.4 

385.75 

535.5* 



(tons) 
.154 

.16 

.166 

.133 

.148 

.184 



* Marine Eng'g, Seaton. l Includes 2 tons of spare gear. * Includes 8 tons of 
spare gear. * Includes 3 . 5 tons of spare gear. 



Digitized 



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306 



\ 



HULL CONSTRUCTION 
Weights op Engines Au>ne* 



Horse Power 


Type 


Weight 
Lb. 


12 


Compound 

n 

u 
u 

Triple 

tt 

tt 
tt 
<« 
n 
tt 
u 
tt 
tt 


290 


25 


590 


70 


1,509 

3,050 

1,075 

2,100 

3,050 

4,450 

5,900 

10,000 

12,992 

17,024 

22,200 


90 


75...... 


150 


200 


275 


325 


425 


550 


800.... 


1,000 


1,500 


32,150 





* High speed engines built by Chas. Seabury & Co., New York. 

Boiler Weights. — Weight of Scotch boilers without water per 
sq. ft. of heating surface is from 25 to 30 lb., and for water tube 
12 to 20. The weight of the contained water per square foot of 
heating surface is from 12 to 15 lb. for Scotch boilers and from 
1.5 to 3 lb. for water tube. Thus Scotch boilers with water will 
weigh from 30 to 35 lb. per square foot of heating surface, and 
water tube will weigh from 13.5 to 23 lb. 

Weight of 3-furnace single-end Scotch boiler, 10 

ft. 6 ins. long by 13 ft. 6 ins. dia., without water 25 tons 
Weight of water 15 

Total 40 tons 

Weight of 3-furnace double-end Scotch boiler, 18 

ft. long, 13 ft. 6 ins. dia., without water 45 tons 

Weight of water 25 

Total 70 tons 

Three-furnace double-end Scotch boiler, 21 ft. 10 ins. long by 
16 ft. 5 ins. dia., weighed empty, 105 tons.. Twenty-nine such 
boilers were installed on the White Star steamer Britannic (1915). 
[Steamer Britannic mentioned above sunk in European War 1916.] 

Digitized by VjiOOQ 1C 



MISCELLANEOUS WEIGHTS 307 

Four-furnace single-end Scotch boiler, 11 ft. long 

by 16 ft. dia., without water 40 tons 

Weight of water 20 

Total 60 tons 

Four-furnace double-end Scotch boiler, 20 ft. 

long by 16 ft. dia., without water 70 tons 

Weight of water . . 40 

Total 110 tons 

Formula for, Finding Weight of a Single or Double-End Scotch 
Boiler* 

Let D = diameter of boiler in feet 

L — length of boiler in feet 

P — working pressure 
C for ordinary single-end boilers «= 725 
C for ordinary double-end boilers = 765 

Weight of bare boiler in tons = ^ X L^X \/P 

Formula for Finding Weight of Water (assumed to be cold) in 
Scotch boilers. 

Assume the water to be 7 ins. above the top of the combustion 
chamber 

D = diameter of boiler in feet 
L = length of boiler in feet 

ryt w t 

Weight of water in tons = — 

Miscellaneous Weights. 

Ordinary fire bars, 5 ft. 6 ins. long 66 lb. 

Ordinary fire bars, 5 ft. ins. long 691b. 

Howden's fire bars, 5 ft. 9 ins. long 47 lb. 

Howden's fire bars, 5 ft. 6 ins. long 45 lb. 

Weight of fire bricks 140 lb. per cubic foot. 
Weight of covering (lagging) about one-half a pound 
per square foot. 

Above formula from Marine Boilers, J. Gray. 

Digitized by LjOOQ LC 



308 



HULL CONSTRUCTION 



Weights of Water Tube Boilers 1 
(No water included.) 



Grate Surface 
Sq. Ft. 


Heating Surface 
Sq. Ft. 


Weight 
Lb. 


3.5 


120 
222 

333 

516 

307 

521 

750 

1,087 

1,310 

1,649 

1,920 

2,846 

1 1,650 

* 3,300 


1,290 
2,170 
4,020 
6,520 
3,550 
5,600 
8,180 


4.94 


9.5 


12.25 


8.48 


12.9 


21.0 : 


33.4 


9,670 
14,100 
16,500 
22,680. 


41.0 


39.5 


53.75 


77.57 


29,460 


52.0 : 


17,000 
30,000 


101.0 





1 Boilers built by Cbas. Seabury & Co., New York. They have a single steam 
drum connected to two lower or mud drums, one on each side, by two nests of 
bent tubes inclosing a large combustion chamber. 

' Special. 

Finished Weight of Machinery, "Steam Up, 1 ' cargo steamer 377 
ft. bet. perps., 49 ft. 3 ins. beam, 28 ft. 9 ins. deep, draft 23 ft. 6 
ins., displacement 9750 tons, block coefficient .78. Two single end 
Scotch boilers 16 ft. dia. X 12 ft. long, 180 lbs. working pressure, 
each with three furnaces, Howden's forced draught, total heating 

surface 6200 sq. ft., total grate area 120 sq. ft., engine jx » 

68 revs, per min., 1. H. P. 1900, giving a speed of 10 J4 knots. 



Main Boilers (bare) 

Boiler mountings. . . . '. 

Furnace fittings (ex. fronts) 

Smoke boxes 

Funnel and fittings 

Ventilators 

Floor plates, gratings, etc. . . 
Sundries in boiler room 

Water in main boilers 

Lagging 

Fire bricks and clay 




207.20 



WEIGHTS OF DIESEL ENGINES 



309 



Howden's Forced Draft 

Fan engine 

Furnace fronts ". 

Retarders 

Air trunks and heater boxes 

Main Engines — proper. 

Condenser 

Thrust shaft and block 

Tunnel and propeller shaft 

Pipes, valves and pieces 

Ballast pipes and chests 

Floor plates, gratings, etc 

Special spare gear 

Outfit and sundries in engine room . 

Water in engines 

Lagging 

Auxiliaries 

Weir's pumps and heater 

Filter 

Evaporator 

Ballast pump 

Donkey pump 

Fresh water donkey pump 

Telegraphs 

Ash hoist 

Auxiliary condenser 

Winch Outfit 

Donkey boiler (complete) 

Feed pump for 

Winch pipes 



Total Weight of Machinery, "Steam Up" . . 



Tons 



2.5 
3.15 
1.75 
4.6 
107.0 
9.5 
7.25 
45.85 
9.0 
5.7 
11.8 
12.0 
5.0 
4.5 
1.0 

3.8 
.8 

2.5 

1.6 
.4 
.3 
.1 
.8 

1.4 

20.0 

.3 

5.2 



Tons 



12.00 



218.60 



11.70 



25.50 



475.00 



[Above steamer from Marine Eng'g Estimates, C. R. Bruce.] 

Weights of Diesel Engines 

500 h. p. Diesel engine in motor ship Vulcanite, 180 r. p. m., 
engine alone weighed 42 tons or 188 lb. per b. h. p., entire plant 
with piping reservoirs, etc., 85 tons, equivalent to 380 lb. per b. h. p. 

Twin Diesel engines with a total of 1,600 h. p. in motor ship 
Monte Penedo, both weighed 110 tons, engines alone, piping reser- 
voirs, and accessories 44 tons, reserve air compressor about 6 tons, 
total 224 lb. per b. h. p. 

See also section on Diesel Engines. 

DATA ON VESSELS 
Merchant Vessels. — Under this heading are included ocean-going 
vessels for carrying passengers and freight. See also sections on 
Types and Structural Features. 

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HARBOR VESSELS 313 

Harbor Vessels and Steam Yachts. — Under this heading are 
included steamers engaged in the excursion business carrying pas- 
sengers and freight for short distances but never out of sight of land, 
also tugs and lighters. See pages 314 and 315. 

Excursion steamers are usually side wheelers, although stern 
wheelers are very common on the Mississippi River and its tribu- 
taries. Side wheelers with large deck areas are obtained by extending 
the decks over the hull. In estimating on the carrying capacity, 
7 sq. ft. per person is a fair average. Few are built to the rules of 
any society or with double bottoms, the owners following the 
structural details of their previous vessels. The frames are often of 
bulb angles with the top of the floor plates flanged over, thus doing 
away, with reverse frames. In long, shallow draft vessels, the 
hull is strengthened by longitudinal trusses from the floors to the 
main deck. Above the main deck there may be several uprights 
or posts over which pass rods that are connected to the hull at both 
ends to prevent it from sagging. The deck beams may be of bulb 
angles with one on every frame. The guard beams should be 
bracketed to the sheer strake and secured to the lodger plate in- 
stead of the main deck beams extending from outside to outside. 
Guard braces may be of trusses, pipe, or solid bars. Sponsons are 
required only on the largest steamers. 

The machinery of side wheelers varies from the old simple beam 
engine to the modern compound and three-cylinder compound 
inclined and four-cylinder compound double inclined. The simple 
beam engine has great durability, low initial cost and low mainte- 
nance. The boilers for this type of engine are of the flue and return 
tubular type having a working pressure of around 55 lb., with long 
grates, high fire boxes, and simple forced draught, both under and 
over the grates. With inclined engines, they have Scotch boilers, 
steam 130 to 180 lb., equipped with Howden's forced draught 
system. Stern wheelers have horizontal engines (see section on 
Marine Engines). 

Tugs for ocean towing are preferably of steel, while for harbor 
service of wood, as also are lighters. Steam yachts of 150 ft. or 
over have steel hulls. Tugs and yachts having steel hulls are 
usually built to the rules of a classification society. 

Motor Ships. — These are built with steel hulls, classed by Lloyd's 
or other society, and engage in foreign and domestic trade. They 
are driven by Diesel or semi-Diesel engines, the auxiliaries (winches, , 

Digitized by VjiOOQ 1C 









Excursion Vessels, Tugs, 


Type of Vessel 


Length 

Between 

Perpendiculars 


- Beam 


Depth 


Draft 


Material 
of Hull 


Carrying 
Capacity 


Tug * 


70' 6* 
75' 0* O.A. 


18' 8* 


7'0* 


4' 3* 


Wood 










109' 0* O.A. 
90'0"O.A. 

102' or, 


23' 0* 
20' 0* 

20' 7" 


11' 3' 
9'8» 

13' 0* 


9'0* 
12' 6' 


Wood 
Wood 

Wood 








Tug ••••ii to** » *■«.» 


.... 


Tttg -rv*»».r.. 


119' 6* 
130' 0* O.A. 


25' 9* 


lo'3» 


12' 0» 


Steel 


• «»» 


Tug '. 


158' 0* 

iey o* o.a. 


29' 4 # 


19' 0* 


.... 


Steel 








Lighter T 


95' 0* 
110' 0* 
130' 0" 


28' 0* 
30' 0» 
28' V 


9'0* 
11' 0* 
12' V 


.... 


Steel 
Steel 
Steel 


820 tons 


Ughtw... .-. T - TTt - f .-•-•- . 


450 tone 


Day Excursion „ A . 


500 pas- 
sengers) 


Stern Wheel 


135' 0* 
156' 0* O.A. 


23' 4' 


4'0* 


8'9* 


Steel 




Western River 




Side Wheel Excuraion . . 


180' 0* 


32' 0*. over 
guards. 54' 0* 


9'0» 


6'0* 


Steel 


1000 


Side Wheel Excursion . . 


180' 0* 


31' 0» over 
guards 53' 0* 


WO* 


.... 


Steel 


.... 


Side Wheel Excursion . . 


190' 0* 


34' 0». over 
guards 00' 0* 


irr 


rv 


Wood 


2200 


j8ide Wheel Excursion . 


200' 0» 
211'0"O.A. 


33' 0*\ over 
guards 59' 0* 


9/0* 


4'0* 


Steel 


.... 


8erew passenger. ...... 


200' 0» 
213' 0» Q.A. 


35' 0*, over 
guards 42' 0* 


n' r 


WO* 


Steel 


541st 

48 3d 


Side wheel passenger. . . 


260' 0* 
263' 0* O.A. 


35' 0*\ over 
guards 63' 0' 


ll'V 


...- 


Steel. 


.... 


Steam Yacht 


153' 0* 
185' 0* OJL 


83' if 


iro* 




Wood 























314 



Lighters and Steam Yachts 



— 


I.H.P. 


Boilers 


Steam, 
Lb. 


Speed, 
Miles 
Per 
Hour 


Remarks. 


Twin screw 
8 X18 

12 


total, 
300 


Water tube: grate sur* 

face, 35 sq. ft.; besting 

surface, 110 sq. ft. 


200 


11 


Oil burner, 1,700 gal. of oil; 
fresh water, 1.300 gab; con- 


15 X32 
22 


450 


One 12' dia. by 11' 7" 

long: grata, 54 sq. ft.; 

besting, 1772 


165 


12 


Condenser, 632 sq. ft. ; wheel, 
8'0*dis,byl0 7 9*pitoh. 


14 xao 

20 


.... 


Loco, type: 8' 4* dia.; 

13' 0* long; grate, 50 

sq. ft.; heating, 1,300 

sq.ft. 


125 


12 


Bunker, 20 tons; fresh water, 
3.000 gala.; cond. ( 550 sq. 
ft.; wheel, 7' 4* dia.; 10* 
pitch. 


1ft X 32 

22 
138 rev. 


580 


One— 11' 3* dia. by 
12' 8* long; three 36' 
furnaces; grate sur- 
face, 54 sq. ft.; heat- 
ing surface, 1,365 sq. ft. 


160 


13 


Cooling surf see of condenser, 
843 sq. ft.; wheel, 8' 0* dia. 
by 10' 9* pitch; coal bunker 
50 tons; fresh water, 6,900 
gallons. 


22 X48 

36 
130 rev. 


1250 


Two— 14' 6' dia. by 
12' long 


140 


•• 


Total heating surface of boil- 
ers, 4,600 sq. ft.; grate. 168 
sq. ft.; condenser, 2,500 sq. 


1? X 27 X 45 


1100 


Two— 13' 0* dia. by. 
1' 2* long 


175 


•-• 


Tow 3 barges of a total ca- 
pacity of 4,000 tons at 9 
knots; bunker, 300 tons. 


30 


13 X26 

18 


...w 


One boiler 10' 0* dia. 
by 10' 0* long 


125 


•• 


Surfsce condensing; wheel 6' 
9* dia.; 4 blades. 


Single 22 


.... 


One boiler 10' 0* dia. 
by 16' 0* long 


125 


- 




26 




18X36 
/ 30 


650 


Two water tube: heat- 
ing surface, 3,350 sq. 
ft.; grate, 106 sq.ft. 


..-. 


- 


Weight of boilers and water, 
20 tons. 


Comp. horiiontsl 

12* A 24* by 6' 

Stroke 


400 


Western river type, 3 
off, 40* dia. by 28' long 


180 


10 


Stern wheel; Western river* 
19' 6* din., by 16' wide, 30 
buckets. 


Single inclined 

25*dia. by V 

stroke 


600 


Two cylindrical, 10' 

3* dia. by 10' 0* 

long 


00 


14 


Paddle wheels 18' 5* dia., 7' 
6* long, 3' wide. Displace- 
ment, 480 tons; surface con- 
denser. 1,380 sq. ft 


8ingle,.42"die, 
by UK stroke 


\ 




60 




Paddle wheels, 24' din.; coal 




bunkers, 25 tons: freshwater, 
two tanks, each 750 gallons. 


Snsje. 62* dia. 
by 9 7 stroke 


1400 


Two wagon top 


52 


19 


Paddle wheels, 23' 6* dia.; 
llbuekets. 


Single. 51* dia. 
by 8* stroke 


.... 


One wagon top, 10' 
dia. by 27' long 


50 




Surfsce condensing: wheels, 
20' dia.; 35 rev. per min. 


18 X 29 X 48 
30 


1350 


Two boilers, 10' 6* 
dia. by 12' 9* long 


... 


15 


26 state rooms, river service; 
wheel, 10' 6* dia.; 4 blades. 


Single cylinder, 

55' di*. by 10' 

stroke 


1800 


Two, 9' 6* dia. by 
26' 6' long 


50 


21 


Jet condenser. 


13HX21 X34 




Two water tube: best- 
ing surf see, 3,748 sq. ft. 
grate surf see, 95 sq. f 1 


... 


18 


Carries 10.000 gsL of water, 
100 tons of coat 


21 



315 



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HULL CONSTRUCTION 



capstans, etc.) being steam or electric operated. For cost of up- 
keep see Internal-Combustion Engines. 

Motor Boats. — There are no rules for their scantlings. As to the 
hull forms there is the V bottom for cruisers and runabouts where 
the cross sections are Vs, and the ordinary curved or round bot- 
tom. Hydroplanes have practically flat bottoms with steps, the 
hydroplane lifting and running on a step when at full speed. Gaso- 
line engines have superseded steam for pleasure craft from 30 to 
100 ft., for not only are the former easier to handle, but they take 
up less space and a smaller crew is required. 

Motor boats over 15 tons come under the supervision of the U. S. 
Steamboat-Inspection Service, and are classed as steamboats. 
While limited as to carrying capacity motor boats are allowed more 
passengers than steamboats of the same size. Their operating 
conditions are set forth in their certificates of inspection. In some, 
the equipment includes air tanks, under the decks, of sufficient 
size to float the boat with her complete complement of passengers 
with the hull full of water. Boats over 65 ft. long, carrying freight 
for hire are required to have a licensed pilot and engineer. 

After January 1, 1915, the U. S. Steamboat-Inspection Service 
requires that all ocean steam vessels of over 2,500 gross tons carry- 
ing passengers and whose course takes them 200 miles or so off- 
shore shall be equipped with not less than one motor-propelled 
lifeboat. 

See tables of Motor Ships and Motor Boats. 

Schooners and Sailing Vessels with Motors. — The schooners in 
the following table are typical ones engaging in the coastwise trade 
in the United States, the larger sizes trading with South American 
countries. The fishing schooners given run out of Boston, Mass. 
Schooners generally have wood hulls. 

Sailing vessels with motors of the larger sizes are ship rigged, 
have steel hulls and engage in the transatlantic or ocean trade. 
Many of these vessels are owned by Norwegians. 

See Wood Vessels. 

Sailing Vessels Fitted with Motors 



Length 

Breadth 

Depth 

Deadweight (tons) 

Number of Engines 

Brake h. p. of each 

Total brake h. p 



97' 5" 


135' 0* 


142' 0* 


165' 0' 


226' 0* 


27' 3* 


30' 0* 


26' 9" 


33' 0' 


36' 0' 


12' 3* 


10' 10* 


15' 8* 


12' 9' 


23' 6* 


335 


500 


460 


750 


1900 


1 


1 


1 


1 


2 


80 


160 


120 


240 


120 


80 


160 


120 


240 


240 



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42' 8' 
26' 10* 
3900 J 
2 

160 
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Fishing Schooners Fitted with Motors 



Length 

Breadth 

Depth 

Gross tons . . . 

Net tons 

Engines 

Speed 

Consumption 



~ 96' 


100.1' 


23.7' 


22.7' 


11' 


9.8' 


115 


94 


79 


64 


Two 4-cycle each 
37.5 h.p. 


Two 4-cycle each 
37.5 h.p. 


7H knots 


9 knots 


6H gals, of gasoline 


7 gals, of gasoline 


per hour 


per hour 



103' 
24' 
11.8' 
141 
93 
Two 4-cycle each 
50 h.p. 
8 knots 
7}i gals, of gasoline 
per hour 



MISCELLANEOUS VESSELS 

Oil Carriers. — Owing to the extensive use of oil and the finding 
of it in many parts of the world, several types of bulk oil carriers 
have been developed. Among them may be mentioned: (1) those 
with the usual transverse system of framing as per Lloyd's rules 
or other classification society; (2) those built on the longitudinal 
or Isherwood system; and (3) those built with large cylindrical 
tanks with the usual transverse framing modified to suit. 

Ships built according to (1) and (2) have a complete subdivision, 
there being a longitudinal bulkhead with several transverse. 
Lloyd's specify "that oil compartments are not to exceed 24 to 28 
ft. in length." As a rule oil carriers are built with the propelling 
machinery aft, thus giving the entire forward part of the vessel 
for the carrying of oil. In vessels having the machinery aft, a poop 
must be fitted of sufficient length to cover the machinery space. 
When the engines are amidships the bridge is to be of sufficient 
length to overlap the ends of the middle bulkhead in the oil com- 
partments. The pump room is often amidships even when the en- 
gines and boilers are aft. 

Some vessels are designed to have sufficient stability when empty 
or with just enough water ballast to give the proper trim, but this 
gives a vessel, when loaded, excessive stability and makes her an 
uncomfortable roller. In others when the oil is discharged and 
they are to proceed again to sea without a cargo it is necessary to 
fill several of #ie oil tanks with water to get the desired stability. 
This must only be done in port and great care must be taken. 

To provide for the expansion and contraction of the oil each com- 
partment has an expansion trunk large enough to keep the compart- 
ment always full, but with a small free surface so that the fluidity 
of the oil will not cause much if any loss of stability. The trunks 
are arranged so the surface of the oil will not fall below the sides 



nvJ^v^ 



COFFERDAMS 321 

when the vessel is rolling or pitching in a seaway. When the 
breadth of the expansion trunk exceeds 60% of the breadth of the 
vessel or the height of the trunk exceeds 8 ft. above the top of 
the oil compartment, Lloyd's require the plans to be submitted to 
their Committee for special approval. 

Cofferdams are fitted at the forward and after ends of the oil 
space, and when the machinery is amidships they are also fitted 
at each end of the machinery space so that the oil cargo will be 
isolated from the engine and boiler spaces. The cofferdams must 
not be less than two frame spaces in length and must extend from 
the keel to the continuous expansion trunk for the full breadth of 
the vessel. The cofferdams are practically additional bulkheads 
and are connected to the ship's bulkheads by plates and angles. 

The best of workmanship is required in the building of oil carriers. 
The riveting must be thoroughly oiltight, the spacing never ex^ 
ceeding 3 or 3H diameters, and the rivet points left full or convex. 
The caulking side of the center line bulkhead should be reversed 
in each tank and the transverse bulkheads should be caulked on 
the forward side in one case and on the after side in the next. This 
simplifies testing to a great extent. Portland cement is not re- 
quired in compartments where oil is carried. 

When cylindrical tanks are installed, these rest on the top of 
the tank top, the oil not coming in contact with the hull. 

The American Bureau of Shipping recommends that "the three 
deck or spar deck type, with the main or second deck forming the 
crown of the oil holds and the 'tween-deck be dispensed with. 
Furthermore the oil holds are not to exceed 32 ft. in length and 
are to be divided by a longitudinal oiltight bulkhead extending 
to the top of the expansion trunks connected with all the oil holds. 
To provide for the expansion and contraction of the oil, each hold 
or compartment is to connect with one or two trunks extending 
from the deck forming the crown of the hojds to the deck above." 

Some of the latest bulk oil carriers are shelter deckers. y All the 
societies insist that vessels carrying oil in bulk be well ventilated, 
requiring that efficient means be provided for clearing the com- 
partments from dangerous gases by the injection of steam or other 
artificial ventilation. •* 

Lloyd's Rules state: "Oil fuel the flash point of which by Abel's 
close test does not fall below 150° F. may be carried inordinary 
cellular double bottoms either under engines or boilers or under 
ordinary cargo holds, also in peak tanks or in deep tanks or in oil 
bunkers specially constructed for this purpose. 



322 



HULL CONSTRUCTION 




Figure 50. — Pump Installation on Tanker La Brea. 



"Cellular double bottoms when fitted for oil fuel are to have 
oiltight center divisions and the lengths of these compartments 
are to be submitted for approval. 

"All compartments intended for carrying oil fuel must be tested 
by a head!of water extending to the highest point of the filling pipes, 
12 ft. above the load line or 12 ft. above the highest point of. the 
compartment, whichever of these is the greatest. r * 

"Each compartment must be fitted with an air pipe to be always 
open, discharging above the upper deck. It is recommended 

Digitized by VjUUv LC 



OIL FUEL COMPARTMENTS 323 

that all double bottom compartments used for oil fuel should have 
suitable holes and doors of approved design fitted in the outer 
bottom plating. 

"Efficient means must be provided by wells or gutterways, and 
sparring or lining to prevent any leakage from any of the oil fuel 
compartments from coming into contact with cargo or coal, and to 
ensure that any such leakage shall have free drainage into the 
limbers or wells. 

"If double bottoms under holds are used for carrying oil fuel 
the ceiling must be laid on transverse battens, leaving at least 2 
ins. air space between the ceiling and tank top, and permitting 
free drainage from the tank top into the limbers. 

"The pumping arrangements of the oil fuel compartments must 
be absolutely distinct from those of other parts of the vessel. 

"If it is intended to carry sometimes oil fuel and sometimes 
water ballast in any of the compartments, the valves or cocks 
connecting the suction pipes to these compartments with the ballast 
donkey pump and those connecting them with the oil fuel pump 
must be so arranged that the oil may be pumped from any one 
compartment by the oil fuel pump at the same time as the ballast 
donkey pump is being used on any other compartment. 

"All oil fuel suction pipes should have valves or cocks fitted 
at the bulkheads where they enter the stoke hold, capable of being 
worked both from the stoke hold and from the deck. Valves or 
cocks similarly worked are to be fitted to all pipes leading from 
the settling or service tanks. 

"Oil fuel pipes should, where practicable, be placed above the 
stoke hold and engine room plates, and where they are always 
visible. 

"No wood fittings or bearers are to be fitted in the stoke hold 
spaces. 

"Where oil compartments are at the sides of or above, or below 
the boilers, special insulation is to be fitted where necessary to 
protect them from the heat of the boilers, smoke boxes, casings, etc. 

"Water service pipes and hoses are to be fitted so that the stoke 
hold plates can at any time be flushed with sea water into the 
bilges. 

"If the oil fuel is sprayed by steam, means are to be provided 
to make up for the fresh water used for this purpose. 

"If the oil fuel is heated by a steam coil the condensed water 
should not be taken directly to the condensers, but should be led 

Digitized by VJiOOQlC 



324 HULL CONSTRUCTION 

into a tank or an open funnel mouth and thence led to the hot well 
or feed tank." 

* General Notes on Oil Carriers. — Oil in tankers is carried to 
the skin of the vessel (except those with cylindrical tanks) and in 
many cases no water ballast tanks are below the oil tanks but may 
be in the machinery space. Vent pipes must be fitted to the oil 
tanks, the tops of the pipes having covers of wire gauze sheets to 
prevent sparks or hot cinders from entering the tanks. 

The pump room may be forward of the machinery space (which 
is usually aft), or it may be amidships with water ballast tanks 
below it. In some large steamers there are two pump rooms, one 
forward of the machinery space and the other amidships; 

The oil pumps are kept entirely separate from the pumps which 
fill or clear the water ballast spaces of water, aftid no water ballast 
pipe passes through an oil compartment or vice versa. There 
are two main lines of suction pipe, one on each side of the center 
longitudinal bulkhead. Each line has a suction to each tank on 
its own side of the ship t and may have one passing through the longi- 
tudinal bulkhead to the corresponding compartment on the other 
side. Two valves are fitted to each suction and these are operated 
by rods on the weather deck. There are thus two sections in each 
compartment and four in each tank, an arrangement which per- 
mits both sides of the vessel to be dealt with through the same line 
simultaneously. In other cases each line has only one suction on 
each side of the center line bulkhead with valves worked from the 
upper deck, a master valve being in each line at the bulkheads 
also controlled from the upper deck. 

When oil is carried in the summer tanks, these may have drop 
valves which permit the contents of a tank being drained into 
the one immediately below and then discharged through the main 
lines. This involves carrying the same quality of oil in the 'tween- 
deck spaces as is carried in the corresponding hold space. On 
many vessels the summer tanks have an independent line of about 
4 ins. diameter. 

In emptying the tanks of oil, the pumps will clear the whole of 
the cargo in the tanks but will leave the pipe lines full. Ordinarily 
this is drained into the end compartment and dealt with by a hand 
pump or by buckets. 

Steam heating coils are often placed in the tanks, for when heavy 

* Abstracts of a pamphlet on "Description and Construction of Oil Steamers" by 
J. Montgomerie of Lloyd's. 



Digiti 



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PIPING ARRANGEMENT 325 

viscous oil is carried it is difficult to handle it at ordinary tem- 
peratures; in fact a temperature of 120° may be required. 

Steam fire extinguishing apparatus is carried by all oil vessels 
and provision is made for steaming out the tanks, which may 
consist of hoses attached to a steam line on deck. Or, instead, a 
system of 6opper pipes with 1 J^-in. branches extend to within a foot 
of the bottom of the tanks. In this case the fire extinguishing 
and steaming out installations may be combined in one set of pipes, 
by having holes cut in the pipes just below the deck. 

When general cargo is carried the tanks are ventilated in the 
ordinary way by upcast and downcast ventilators, and when oil is 
carried the ventilators are closed by blank flanges. Except in 
vessels carrying benzine, the tanks are kept as far as possible sealed, 
there being only a vapor cock in the side coamings of the hatch- 
ways. When benzine is carried vapor pipes of about 2J^ ins. 
diameter are connected to the main tanks, and of 2 ins. to the sum- 
mer tanks, with cocks at each tank, the pipes being led to one of 
about 3 ins. which runs up one of the masts, or there may be two 
such pipes. 

In some cases after the oil has been pumped out the heavy 
air mixed with the gas from the oil is partially removed by opening 
the hatches and fixing up a canvas ventilator the bottom of which 
extends nearly to the top of the floors. The fresh air entering the 
ventilator forces upward the heavy air out through the hatch 
openings. Sometimes a fan assists in the movement of the air. 

See also Loading and Stowing of Cargoes. 

Piping Arrangement. — The following system was installed on 
a 410-ft. steamer, the F. H. Buck, having a cargo capacity of 63,900 
barrels of oil: "Two duplex pumps having 18 inch steam cylin- 
ders, 15 inch oil cylinders with 18 inch stroke. The suction system 
consists of two 12 inch mains run one on each side of the center 
line bulkhead with a 10 inch branch to each tank. Bypass arrange- 
ments are made so that any tank on one side of the ship can be 
emptied and discharged either overboard, through seacocks or 
into any other tank on the opposite side. Each pump can separately 
or together discharge into an 8-inch belt discharge main' running 
along the top of the expansion trunk from which 8 inch branches 
are fitted for discharging overboard or back to the tanks by 6 inch 
branches. Discharges are so arranged that either pump can dis- 
charge into one side of the main or the other and division valves 
are provided so that one pump can be working at a heavier pressure 

Digitized by VjiOOQIC 



326 



HULL CONSTRUCTION 



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LUMBER STEAMERS 327 

than the other. An independent 6-inch suction is fitted to one set 
of the main cargo tanks to discharge into the fuel tanks. The 
discharge system is so arranged that it can be used as suction for 
one or both pumps. Each pair of tanks is fitted with a 6-inch 
equalizing valve. Two turbine fans are fitted in the* pump room 
to discharge air either into the pump room or into 12-inch suction 
pipes to the cargo tanks." See Lloyd's Rules above and also 
General Notes. A midship section of the F. H. Buck is shown on 
page 257. 

Lumber Steamers. — These often have only a single deck with a 
center longitudinal bulkhead, the machinery being aft. They are 
given extra beam, and the main deck is strengthened for carrying 
a deck cargo, and special bulwarks built. Cargoes up to 14 ft. in 
height may be carried on some steamers. An example of a steamer 
designed for the lumber trade is the Wm. O'Brien. She is 361 ft. 
between perpendiculars, 51 ft. beam, 27 ft. deep, draft loaded 21 
ft. 6 ins., Jumber capacity 3,000,000 ft., single deck, watertight 
center line bulkhead entire length of cargo holds from keel to main 
deck, machinery aft, 3 single-end Scotch boilers 13 ft. 8 ins. by 

m c. c • * ion ik • 24K X 3 8^ X 67 nn 

10 ft. 5 ins., steam 180 lb., engme jr-^ , 90 r. p. m., 

i. h. p. 2,150, speed 11 knots. 

Trawlers. — Small steel fishing vessels common in the North Sea 
(Europe) built to Lloyd's rules, with machinery aft, thus giving 
a large hold forward for carrying fish. They are strongly built 
and keep at sea until they have secured a cargo of fish before re- 
turning to port. The fish are caught in a large cone-shaped net 
that is drawn through the water at a slow speed. A typical trawler 
is the following: 130 ft. long, 22 ft. beam, 11 ft. deep, gross ton- 

13 X 22 X 36 
nage 251, net 171, machinery aft, engine ^= , single 

Scotch boiler, steam 150 lb., bunkers 100 tons, speed about 10 
knots on 5 tons per 24 hours. 

Dredges. — Under this heading is included only those with steel 
hulls, ship-shaped, having their own motive power and designed 
for dredging channels to sea ports and offshore work. Many of 
these dredges are equipped with buckets fastened to an endless 
chain, which pick up the material and discharge into hoppers in 
the dredge. When the Jioppers are filled the dredge steams out to 
sea and there discharges. An example of this type is the King 
George, 170 ft. long, 34 ft. beam, 13 ft. 3 ins. deep, steel hull, twin 

Digitized by VjOOQ 1C 



328 HULL CONSTRUCTION 

screw, triple expansion engines each of 600 h. p. •Each engine 
can be coupled to the dredging gear. The dredging buckets have 
a- capacity of 9 cu. ft. each and are fastened on an endless chain. 
There are 32 buckets, with a cast steel body and manganese iron 
cutting lips. The rate of travel is about 16 buckets per minute. 

Another type is the suction, where the material is drawn from 
the bottom through a pipe by means of a powerful centrifugal pump. 
Such a dredge is the Balari, 333 ft. long, 54 ft. 6 ins. beam, 22 ft. 
3 ins. deep, has a hopper capacity of 71,600 cu. ft. The hull and 
machinery are built to Lloyd's highest class. Propelling machinery 
consists of two triple expansion engines. There are four large single- 
end and horizontal boilers, steam 180 lb. The pumping outfit 
placed forward of the hopper in an independent compartment 
consists of a tripie expansion engine directly connected to a cen- 
trifugal sand pump designed to raise and discharge about 5,000 
tons of sand and silt per hour. The pump is connected to a suction 
pipe at the bow. The suction end of the pipe is fitted ,with a spe- 
cially designed nozzle to suit the character of the material to be 
dredged; a grid is fastened to the nozzle to exclude material which 
might choke or injure the pump. The suction pipe is controlled 
by a steam winch placed on deck. The pumping engine has its 
own condenser. 

Shallow Draft Steamers, — These may be divided into stern 
wheelers and tunnel vessels. The former are extensively used on 
the Mississippi River and its tributaries in the United States, also 
on South American and African rivers. Those in the United States 
have generally wooden hulls with boilers forward and engines aft (see 
Marine Engines) . When handling barges they push the barges ahead, 
which is the reverse to ocean towing. They often have three or 
four rudders placed forward of the stern wheel. The rudders are 
given a large area; in fact the immersed area of three rudders aver- 
ages from 115 to 150 sq. ft. A typical example is the towboat 
Warioto, 141 ft. over all, 120 ft. between perps., 27 ft. beam, depth 
at side 5 ft., crown of deck 6 ins., draft with 30 tons of coal on 
board 3 ft. 8 ins., displacement about 270 short tons (2,000 lb.), 
block coefficient .78, steel hull, 4 watertight transverse bulkheads, 
center line bulkhead, 2 longitudinal trusses, 3 boilers, steam 200 lb., 
externally fired, 40 ins. diameter by 24 ft. long, three 9-inch flues, 
three 6-inch, grate area 48 sq. ft., heating surface 1,365 sq. ft., 
engine developed 304 i. h. p., 26.9 lb. of steam being required per 
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329 



yGoigle 



I 




O 


s 


rH 




3 




CO 


M 1-4 
































s 


a 

§ 


O 

rH 


rH 


•8 


WD 


8 


S 


8 

rH 



330 HULL CONSTRUCTION 

towboat 125 ft. long there were installed two tandem compound 

12 X 24 
engines — =^ — which weighed complete with condensers and pip- 

ing 81,345 lb., and the two boilers, including superheaters, stack, 
etc., 94,460 lb. The engines turned a stern wheel 22 to 24 r. p. m., 
18 ft. diameter, buckets 17 ft. long, width 30 ins., 12 arms. Total 
weight of wheel 9,380 lb. 

Tunnel vessels are driven by propellers running in tunnels, the 
propellers being completely surrounded with water. The hulls 
may be built of steel plates, that are shipped in sections and are 
assembled at their destination. The engines are of the usual 
vertical marine type. Below is outlined the Shu Hun, a steamer 
built for service on the Yangtse Kiang, China. Hull of steel, length 
190 ft., beam 30 ft., draft with cargo of 300 tons 5 ft., 2 doable-end 
water tube boilers, supplying steam to two 1,000 h. p. engines. 
Another tunnel boat is the following, which was built to run on the 
Ob River, Siberia. Length on water line 90 ft., beam 15 ft., depth 
5 ft., draft loaded 2 ft. 1J^ ins., steel hull, twin tandem engines each 

6 ^ 8^ 13 ^ t0tal h " P ' ° f b ° th at 28 ° f * P * m ' 13 °- Jet condensin g> 
boiler 5 ft. 8 ins. diameter by 12 ft. 4 ins. long, steam 140 lb. 



FITTINGS FOR CATTLE AND HORSE STEAMERS. 
Weight of Fittings per Head of Cattle Carried. 

Cementing on deck 1% ins. thick 185.00 lb. 

Total woodwork including bolts 139 . 62 

Steel angle footlock clips 11 .43 

Castings and fittings 37 . 19 

Gnawing strips 6 . 00 

Solid cattle stanchions ". 9 . 74 

Hollow stanchions 11 . 02 



Total per head 400.00 lb. 

Sufficient light must be provided for the proper tending of ani- 
mals at all times. For ventilating purposes under deck canvas 
bags should be fitted to ventilators provided with iron rings at 
the bottom, and reaching within 18 ins. of the deck under foot. 

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PRICES, COSTS AND ESTIMATES 



331 



Weight of Fittings per Horse Carried. 

Cement on deck V/k ins. thick 185.00 lb. 

Total woodwork including bolts 273 . 55 

Kicking pieces and bolts 34 . 11 

Castings and fittings 200.34 

Total per horse (London regulation) 693 .00 lb. 

Leaving an American port deduct close division 

boards 135.00 lb. 

Total per horse (American regulation) . . 558.00 lb. 

For complete specifications for the requirements for shipping 
cattle and horses see U. S. Regulations published by Dept. of 
Agriculture. 

The cost of fitting, a steamer with stalls averages $8 to $10 per 
head under deck and $12 to $15 per head on deck. It is estimated 
that the average expense for food for horses and attendants for a 
voyage from New York to Liverpool is about $5 a head. 



PRICES, COSTS AND ESTIMATES 
In Great Britain a fair average price for medium size cargo 
steamers in ordinary times is from $40 to $45 a ton per deadweight. 
Similar vessels if built in the United States would cost approximately 
one and one-half times as much. Below are tables of steamers 
sold in May, 1915, and May, 1916. The rise in price being due 
to the European war and the demand for tonnage. In general 
even the prices quoted in May, 1915, are about 35% above normal. 

Steamers Sold in May, 1915 

Name D.W. Built Price Rate per ton 

Rossia 7,600 1900 £52,000 £6 16 

Whitgift 7,350 1901 51,500 7 

Drumlanrig 7,300 1906 73,000 10 

Rhodesia 7,200 1900 49,000 6 16 

Dongola 7,100 1898 48,500 6 16 

Whindyke 6,500 1901 45,000 6 18 

St. Fillans 6,400 1900 45,000 7 

Kalypso 6,000 1904 60,000 10 

Winnfield 5,800 1901 40,000 6 17 

Woolstan 5,400 1900 40,000 7 8 

Denaby 5,100 1900 38,000 7 9 

Amphitrite 4,400 1897 28,000 6 7 

Leafield 4,340 1905 36,000 8 5 

Hartburn 3,820 1900 28,000 7 6 

Gledhow 3,800 1891 20,000 5 5 

Lula 3,600 1890 19,250 $ 6 

Digitized by VjiOOQIC 



332 HULL CONSTRUCTION 

Steamers Sold in May, 1915 — Continued 

Name D.W. Built Price Rate per ton 

Brynhild 3,450 1899 £30,000 £8 13 

Lisl 3,100 1888 18,000 5 15 

Girda Ambatiellos 2,755 1888 15,000 5 8 

Axminster 2,750 1891 16,500 6 1 

Citrine 2,750 1899 25,000 9 1 

Karmo 2,300 1882 16,000 6 19 

Carmelina 2,300 1904 24,000 10 8 

Allan 1,900 1907 26,000 13 13 

Rign 1,900 1897 19,000 i0 

Arena 1,400 1883 12,000 8 11 

Roar 950 1904 12,000 12 12 

Netta 480 1909 9,000 18 15 

Jessie 180 1902 3,000 15 9 

Steamers Sold in May, 1916 

Name D.W. . Built Price Rate per ton 

Daldoreh 7,700 1907 £150,000 £19 9 

New Steamer 7,500 1916 180,000 24 

Globe 7,450 1909 135,000 18 2 

Crown 7,335 1906 115,000 15 13 

River Forth 7,300 1907 110,000 15 .1 

King 7,300 1906 125,000 17 2 

Orkedal 6,650 1906 178,000 26 15 

Calimeris 6,250 1905 140,000 22 8 

Llansannor 6,250 1900 175,000 28 

Woodbridge 6,060 1900 90,000 14 16 

Navarchus Coundouritos. . 5,550 1898 155,000 27 19 

Agenoria . . 5,200 1902 70,000 13 9 

Huldavore 5,000 1889 100;000 20 

Zulina 5,000 1899 140,000 28 

Astarloa 4,500 1896 101,000 22 8 

New Steamer 3,500 1916 70,000 20 

New Steamer 3,300 1916 85,800 26 

Antonios Embiricos 3,100 1891 62,000 20 

Sirte 2,900 1887 45,000 15 10 

Bizcaya 2,300 1878 41,000 17 16 

Harpalys 2,200 1895 33,000 15 . 

John 1,600 1881 36,250 22 13 

Alfred Kreglinger 1,500 1909 37,000 24 13 

Alfred Dumois 1,300 1890 13,000 10 

Artigas 1,100 1911 20,000 18 3 

Allerton 830 1914 31,000 37 9 

St. Katharine 570 1905 17,500 30 14 

Portaferry 240 1884 6,500 27 1 

The following are miscellaneous quotations made in the United 
States early in 1916. 

Coal barge, ship shape, wood hull, 200 ft. long, 32 ft. beam, by 
20 ft. deep, new to build $35,000. 

Digitized by LiOOQ LC 



PRICES ASKED IN 1916 333 

Dump scow 120 ft. by 35 ft. by 13 ft., 800 cu. yd., wood, good 
condition, but second-hand $4,500. 

Deck scow 90 ft. by 27 ft. by 9 ft., good condition, second-hand 
$1,000. 

Tug, wood hull, 72 ft. long, compound engine, good condition, 
second-hand $8,000. 

Motor boat 30 ft. long, 15 h. p. engine, new to build $1,500. 

Motor yacht 60 ft. long, 35 h. p. engine, new to build $11,000. 

Steamer 257 ft. between perpendiculars. 36 ft. 6 ins. beam, 17 ft. 
3 ins. deep, single deck, long raised quarter deck with short well 
forward, forecastle, machinery amidships, 2,250 tons deadweight 
on 16 ft. draft, $225,000, or if machinery aft $190,000. Prices 
quoted are to build. 

U. S. collier, 13,500 tons displacement, $987,500. 

186 ft. O. A., 1,000 tons (Jisplacement, twin screw, single deck 
vessel for U. S. Coast and Geodetic Survey, bids ranged from 
$163,300 to $266,000. 

The prices asked in 19 16 for delivery in New York of the wooden 
schooners, particulars of which are given in the table on page 319, 
are as follows: 

Built 
165 ft 1883 $25,000 

195 ft 1901 50,000 

196 ft 1891 50,000 

211 ft 1890 50,000 

218 ft x. . . . v 1894 55,000 

In comparing the above prices the age and deadweight should 
be considered. One yard quoted a price of $80,000 for building a 
single deck, 3-mast wooden schooner of 1,200 tons deadweight. 

A wooden schooner 260 ft. long on water line, 46 ft. beam, 23.1 ft. 
deep, gross tonnage 2,556, net 2,125, built in 1901, sold in New 
York in May, 1916, for $195,000. Name of schooner, Rebecca 
Palmer. 

A round bottom work boat 40 ft. long, 9 ft. beam, having good 
lines, with no pilot house, the boat being open with short decks 
forward and aft, oak keel, stem, and frames, white cedar planking, 
galvanized iron fastenings, cost $1,950. The same size but with 
a V bottom cost $1,650, and one 50 ft. by 12 ft. round bottom 
cost $3,000 and with a V bottom $2,400. The above prices do 
not include motor, fuel tank, or auto top; neither do they include 
the installation of the motor, other than a properly constructed 
foundation. 



Digiti 



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334 



HULL CONSTRUCTION 



Estimates on Building a Motor Schooner on the Pacific 
Coast (1916) and of Running her from Seattle, -*. 
Wash., to New York* 
Dimensions, Equipment and Capacity 

Length (custom house) 225' 0* 

Breadth 42' 6' 

Depth. 18' 0' 

Gross tonnage, about 1,250 

Net tonnage, about 1,125 

Speed, knots, loaded (engine) 7 

Lumber capacity 1,500,000 ft. B. M. 

Machinery, two oil motors, 160 h. p. each 

Cost of the Vessel 

Cost of ship complete (wood construction) 

Machinery installation 

All auxiliary installations 



320 

$85,000 

19,000 

18,000 

Cost complete $122,000 

Design, contracts, supervision at 5% $6,100 

Cost of Operating 
Crew — Captain $125 per month 

First mate 90 

Second mate 75 

Cook 50 

Cabin boy : 20 

Eight sailors at $30 240 

Chief engineer 100 

Assistant 75 



$775 X 12 



Food, at 68c per man, 15 men for 1 year. 
Crew expense per day 



$9,300 
3,723 

$13,023 
$35.67 



Engine Room Expense 
One engine: 160 h. p. X l A lb. oil = 80 lb. per 

hour » \i bbl. at 95c per bbl 

Lubricating oil at 41c 

Fuel and lubricant per hour 

Fuel and lubricant, 24 hours 

•From Shipping Illustrated, New York. 



$0,237 
.060 

.297 
$7.13 



Digiti 



zed by G00gk 



OPERATING COSTS OF DIESEL ENGINES 335 

Operating cost per day, 2 engines $14 .26 

Operating cost per year . 5,204.80 

Engine supplies 200.00 $5,404.80 

Taxes at V 2 % 600.00 

Depreciation, 5% * 6,100.00 

Insurance, 7% 8,540.00 

Liability, ty 2 % 1,830.00 

Upkeep and repairs 5,000.00 

Total expense per year $40,497 .80 

Operating cost per day (ship and engine) 110. 95 

Operating cost engine per day 14 .26 

Operating ship only per day $96 . 69 

To New York with Lumber from Seattle, Wash, 

Loading time, 100,000 ft. per day 15 daysv 

Expense of ship loading 15 days at — 

Captain, mate, engineer, cook. . . $12.00 

Food 2.72 

Fixed charges per day 60. 47 

$75 . 19 X 15 days $1, 107 . 85 

Loading, at 85c per M board feet of lumber 1,275.00 

Canal charges, $1.20 per net ton 1,350.00 

Pilotage, canal 22.00 

18 days engines $256.68 

36 days ship 3,480.84 $3,737.52 

Unloading N. Y., 15 days X 96.69 1,450.35 

Unloading, stevedores 1,275.00 



$10,217.72 
Laid down N. Y. per M board feet $6.81 

Operating Costs of Diesel Engines on the Pacific Coast 
of the U.'S. 

Passenger boat 92 ft. long, 16 ft. beam, 5 ft. draft, driven by 
180 h. p. Nlseco Diesel engine, speed 16 miles. Name Suquamish. 

The Suquamish ran miles per day 132 

Season's mileage, May 1 to Nov. 1 24,300 

Season's fuel consumption, gallons 15,000 

Cost of fuel oil for season $325 . 13 

Digitized by VjiOOQLC 



336 HULL CONSTRUCTION 

Cost of fuel oil per day of 12}^ hours $1 . 76 

Cost of fuel oil per mile lj^c 

Cost of repairs, nominal 

Tug 70 ft. long, 18 ft. beam, 10 ft. draft, 240 h. p. Nlseco Diesel 
engine. Name Chickamauga. 

Hours towing 662 

Hours running light 188 

Total working hours 850 

Total fuel consumption, gallons 7725 

Total cost of fuel $167.79 

Fuel consumption per hour, gallons 9.1 

Total cost of fuel per hour 19J£c 

Cost of repairs, nominal. 

Cannery tender 75 ft. long, 18 ft. beam, 8 ft. draft, 120 h. p. 
Nlseco Diesel engine. Name Chomly. 

Working time 1489 hrs. 

Gallons of fuel consumed 8664 

Fuel consumption per hour, gallons 5.8 

Price of fuel per barrel 95c 

Hourly running cost 13 . lc 

Total fuel bill for season $195.97 

Cost of repairs $2.00. 

Repair Costs of Motor Ships 

Name of ship. SembUan London Myer 

No. of voyages made . . 90 in 3 years 60 in 20 mos. 2 per month 
Total cost of repairs... About $2,400 About $1,600 Nil 
Total time lost for re- 
pairs Very little Very little Nil 

time time 

Deadweight capacity . . 300 tons 1750 tons 1750 tons 

Horse power 200 1400 1400 

Fuel consumption per 

geogr. mile 0.02 tons 0.08 tons 0.08 tons 

Fuel consumption per 

i. h. p. hr 0.16 liter 0.18 liter 0.18 liter 

The Diesel engines of the Sembilan, London and Myer were 
built at the Werkspoor Works, Amsterdam. The fuel consumption 
at sea averaged .30 lb. per i. h. p. hour, compared with 1.20 lb. per 
i. h. p. for an oil-fired steamer. 

Digitized by VjOOQ LC 



COST OF ELECTRIC INSTALLATIONS 



.337 



Cost of Electric Installations. — Cost of marine generating sets only, 
$60 to $80 per kw. 

Cost of electric plant complete, including apparatus and in- 
stalling: 

(Data from Stand. Elect. Engr'a Handbook.) 



Type of Vessel 


Size of 
Generating Set 


Lamps 


Total 
Cost 


Tug 


3kw. 
20 kw. 
20 kw. 

150 kw. 


50 

300 

150 lamps 

searchlight 


$1,100 
3,000 


Ferryboat 


Freight steamer 

Oil tanker 


5,000 
7,500 


Passenger and freight 
steamer 


1,200 lamps 

searchlight 

electric heating 

system 


27,000 







Cost of Refrigerating Systems. — Cork insulation alone on sides, 
decks, bulkheads and inner bottom averages about 70 cents per 
square foot of surface for an entire compartment. The cost of the 
insulation, refrigerating machinery, brine tanks, compressors, 
piping, etc., averages for a steamer for carrying frozen or chilled 
meat 70 to 75 cents per cubic foot. These prices could be taken 
for other products also. 

Prices of Steam Engines and Boilers. — The prices of steam engines 
alone as given in the table Weights of Engines Alone, page 306, 
varied from $1.20 to $1.28 per i. h. p. 

Scotch boilers about 10 cents a pound. Water tube boilers as 
in the table Weights of Water Tube Boilers, page 308, varied from 
23 to 25 cents a pound. 
Cost of Fitting up a Steamer for Carrying Cattle, see page 331. 
Percentage of Cost of the Parts of a Motor Boat — The following 
figures apply to motor boats up to about 100 ft. in length, built 
for pleasure purposes and having a speed of around 10 miles an 
hour. 

Per cent. 

Main power plant 24. 2 

Power plant accessories 2.4 

Electrical equipment 7.5 

Miscellaneous equipment 2.7 

Finished hull 46.0 

Deck equipment 11 .0 

Cabin equipment 6.2 

Total cost 100.0 



338, HULL CONSTRUCTION 

The equipment items for a 33-foot raised deck cruiser are as follows' 

Main power plant, 20 h. p., 4-cycle motor, magneto, fuel tanks, 
piping, etc. 

Electrical equipment, running lights, switches, storage battery, 
dynamo, and fixtures.. 

Miscellaneous equipment, charts, marine glasses, navigating 
instruments. 

Finished hull, planked with 1^-inch cedar, mahogany interior 
and cockpit finish, eight built-in lockers, ice box, galley, brass air 
ports, bronze rudder and shoe, steering wheel, skylight, signal 
mast, ventilators, etc. 

Deck equipment, dinghy, life preservers, anchors, moorings, 
buoys, etc. 

Cabin equipment, cushions, chairs, clock, bedding, rugs, stove, 
galley equipment. 

Estimates. In preparing a bid on the building of a vessel or on 
repair work, the bid should be divided into three parts: (1) the 
overhead expenses, (2) the actual cost and (3) the»profi^. In the 
overhead is included such items as taxes, insurance, rent, interest 
on the money invested, salaries of non-producers as clerks, etc., and 
trial trip expenses, preparation of slip, launching ways, etc., directly 
charged to the vessel bid on — or if it is a repair job then include 
wharfage, water, etc. 

The (2) or actual cost includes the cost of the materials and the 
time spent by the workman in completing and putting into place 
the finished product. 

To the overhead expenses and actual cost is added a percentage 
for the profit to the yard for undertaking the work. The per- 
centage is a variable quantity depending on how close the competi- 
tion is and how badly the yard wants the particular contract. 

Workmen in shipyards are divided into two classes, viz., piece 
workers and hour or day workers. Riveting, putting on shell 
plates and other structural work is generally done by piece work — 
while the men in the machine shop, outside machinists installing 
engines, boilers, etc., are paid by the hour or day. Naval Cons. 
W. B. Ferguson, U. S. N., in his book on "Art of Estimating" states — 
"If an operation is to be performed by day work, the relative 
efficiency of the day workers and of piece workers must be taken 
into account in estimating. The cost per day work will average 
between 25 and 50% greater than piece work cost under the 
ordinary form of management." 

Digitized by LiOOQ 1C 



MARINE PROPELLING MACHINERY 



339 



The parts pertaining to the hull are estimated in detail, as the 
cost of the raw material of each part, and the labor on it. The 
labor can only be closely estimated by making a note of every 
operation and the men's time, laying out sheets as the following: — 

ESTIMATE SHEET. 



Estimate No. 
For 








Submitted 

Date of Estimate 




Cost 
Delivered 


Handling 

at 

Yard 


Labor 


Total Cost 


Item 


Time 

(hours) 


Rate 


Total 
Labor 


Material 
and Labor 

















All detail figures should be checked by referring to the costs of pre- 
vious similar work. In many cases the hull cost can be reduced to a 
pound price — and the labor bears a percentage to the cost of the 
raw material. .For example, the figures in the table Labor Costs 
per Pound are for direct labor cost only for the hull work of four 
types of vessels. The labor costs per pound in the table are for 
vessels built mostly by day work, and are considerably higher on 
the average than would be expected for piece work, bonus or 
contract system. The types selected for comparison are all United 
States Naval vessels: (1) battleship of New York class, (2) torpedo 
boat destroyer of 1,000 tons, (3) collier of Jupiter class and (4) 
standard 500-ton Navy coal barge. 

Relative Cost of Different Types of Marine Propelling Machinery 



Type of Vessel 



Description of Machinery 



Cost per 
1. H. P. 

(trial trip) 



Cost per 

ton of 
Finished 

Wt. 
Steam Up 



Lance cargo steamers 

Medium cargo steamers . . 

Intermediate ocean liners 

Medium passenger and 

cargo 



Twin screw, 3 cylinder, triple 
Single screw, 3 cylinder, triple 
Twin screw, 4 cylinder, quad. . 
Twin screw, and single screw, 
3 cylinder, triple 



£5.5-£6.5 
£5.0-£5.5 
£6.25-£7.5 

£5.5-£6.26 



£27.-£33. 
£22 .-£27. 
£33.-£39. 

£30.-£36. 



Table from Marine Eng'g Estimates, C. R. Bruce. 



In estimating on the cost of machinery (boilers, engines, etc.) 
sheets may be ruled similar to the one for the hull as given above, 
so the different parts may be itemized for obtaining the costs of the 
raw materials and the labor. Note the following table : 

Digitized by VjiOOQIC 



340 



.HULL CONSTRUCTION 



Direct Labor Costs per Pound in Cents* 



Items. 



& 



Ordinary steel in hull 

Plating, outer and inner bottoms 

Framing 

Bulkheads 

Decks 

Bridges, hammock berthing and cofferdams 

Foundations for armor, turrets and guns 

Work around secondary battery, etc 

Foundations for machinery i 

Inclosures • 

Metal masts and spars 

Rivets 

Steel castings and f orgings forming structural parts of hull . 

Deck pillars or stanchions 

Deck planking and wood in docking and bilge keels 

Linoleum, tiling, etc 

Joiner work 

Carpenter work 

Wood ladders 

Wood masts and spars 

Metal ladders 

Pamt, cement, etc 

Turret turning machinery, roller tracks and rollers 

Fixed ammunition hoist machinery and gear 

Rudder and' steering gear 

Cranes, davits and other gear for handling boats 

Coaling gear v 

Pumping and drainage, and sea connections 

Plumbing work, including fresh and salt water systems. . . . 

Ventilation . . . 

Anchor and cable gear 

Warping and towing gear 

Hand rails and awning stanchions, canopy frames and hatch 

cranes 

Air ports, deck lights and light boxes 

Water tight doors 

Non water tight doors , 

Manhole covers, scuttles, etc 

Miscellaneous hull fittings 



7.7 
4.0 
7.0 
8.0 
6.0 
15.0 

15.0 
10.0 
15.0 

25.0 
16.1 
12.1 
8.0 
8.0 
30.0 
12.0 

35.0 
25.0 
13.4 

20.0 
13.8 
10.0 

40.0 
25.0 
51.0 
13.3 
15.0 

30.0 
25.0 
44.2 
18.1 
4f30. 
25.0 



.3 



1.1 
1.0 

.7 
1.1 

.6 



11.0 



1.1 



38.0 
4.0 
2.5 



3.0 



2.3 
0.9 



17.1 
8.7 

16.8 

17.2 
2.6 

13.3 



0.8 



* From "The Art of Estimating the Cost of Work." 
Constructor, U, 8. N. 



W. B. Ferguson, Naval 



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SECTION VI 
MACHINERY 

STEAM, FUELS, OIL, BOILERS, MARINE STEAM ENGINES, 

STEAM TURBINES, STEAM PLANT AUXILIARIES, 

INTERNAL COMBUSTION ENGINES, PIPING, 

TUBING, VALVES AND FITTINGS 

STEAM 

One British Thermal Unit (B. t u.) is the quantity of heat re- 
quired to raise the temperature of one pound of water one degree 
Fahrenheit when the water is at its greatest density (39.1° F.). 
Thus to raise the temperature of one pound of water from 39° to 
40° requires one B. t. u., and to raise the temperature of one pound 
of boiler feed water from 67° to 212° requires approximately 212 — 
67 « 145 B. t. u. 

1055 watt-seconds 



1 Heat unit (B. t. u.) equals 



778 foot-pounds 
.000293 kw. hour 
.000393 h. p. hour 
Calorie (French or Metric Unit of Heat). — One calorie is the 
quantity of heat required to raise one kilogram of water one degree 
Centigrade. One calorie = 3.968 B. t. u. = 4158.6 watt seconds = 
3065 ft. lb. = .0015 h. p. hour. One B. t. u. = .&52 calorie. 

Mechanical Equivalent of Heat. 

1 B. t. u. = 778 foot-pounds 

1 foot-pound = ==£ B. t. u. 

Specific Heat of Steam, or the coefficient of its thermal capacity, 
is the ratio of the heat required to raise its temperature one degree 
to that required to raise the temperature of water one degree 
from the temperature of its greatest density, viz., 39.1° F. 
Specific heat of saturated steam = . 48 
Specific heat of superheated steam = . 77 r 
^4-1 



342 MACHINERY 

Total Heat of Steam (H) is the quantity of heat required to 
generate one pound of steam from water at a temperature of 32° F. 
to any given temperature and pressure. It is made up of the latent 
heat of evaporation and the sensible heat indicated by the ther- 
mometer. 

Let t = temperature of steam 

Then H (total heat of steam) = 1082 + .305 times t 

Latent Heat of Steam (L) is the quantity of heat required to trans- 
form one pound of water into steam at a given pressure, together 
with an amount of heat required to produce the external work 
.done by increasing the volume of the water. 

internal heat + external heat = latent heat of steam 

Then L (latent heat of steam) = 1114 — .7 times t f where t = 
temperature of the steam. 

In raising the temperature of one pound of water from 67° to 
212° F., 145 B. t. u. are required, but after a temperature of 212° 
is reached, heat can be imparted to the water until it is all changed 
into steam with no increase in temperature, 970.4 B. t. u. being 
required for the change in converting one pound of water at 212° 
into one pound of steam at atmospheric pressure. The value 
970.4 B. t. u. is known as the latent heat of steam or the heat 
of vaporization of steam at 212°. Some authorities, instead of 
using 970.4, use 966. Thus to change or evaporate into steam 
one pound of water at 212° requires 970.4 (or 966) units of 
heat. 

Efficiency of the Steam in an engine is the ratio of the work 
done on the pistons in a given time (as measured by indicator 
diagrams) to the energy contained in the steam passing to the en- 
gine during the same time. In good modern engines using from 
14 to 18 lb. of steam per i. h. p. per hour, this corresponds with 
steam efficiencies of 16 J^ to 12 H%- 

Steam Consumption per 1. h. p. in condensing engines averages 
about 13.65 lb. 



Type of Engine 


Pounds of Steam 

per i. h. p. per 

Hour 


Single non-condensing 


30 


Single condensing 


20 


Compound condensing 


15 


Triple expansion condensing 


12 







y Google 



KINDS OF STEAM 343 

(See tables under Turbines; also under Marine Engines.) 

Kinds of Steam. — Saturated steam is steam of the temperature 
due to its pressure — not superheated. y 

Superheated steam is steam heated to a temperature above that 
due to its pressure. The advantages claimed are fuel economy, 
water economy, and consequently increased carrying capacity of 
the vessel. Superheated steam is more common in Europe than 
in the United States. The degree of superheat may be divided as 
follows: low from zero to 50° F.; moderate 50° to 125°; and high 
125° and upwards. Generally with turbines working at a pressure 
of 175 to 200 lb. there is a saving in steam consumption of about 
one per cent, for each 10° of superheat — which is true for recipro- 
cating engines also. In a test made on a triple expansion engine, 
with an average superheat of 85° at the engine, there was a saving 
in the coal of about 9% (see table under Superheaters). With 
superheated steam the pipe lines and fittings should be of steel 
and cast steel respectively. Other materials as copper and bronze 
lose their strength in high temperatures and should be avoided in 
piping and fittings for highly superheated steam. As to the engine 
valves the high pressure cylinder valve should be of the piston 
type, preferably with an inside admission. For equal engine 
power the cut-off with superheated steam must be somewhat in- 
creased above that for saturated steam. 

Superheated steam is greater in volume than saturated steam 
of the same pressure. Linde's equation is 

p v - .5962 T - p (1 + .0014 p) ^ l50 ^ 000 _ .0 833 ^ 

where p = pressure in pounds per square inch, 
v = volume in cubic feet, 
T = absolute pressure. 

The table on page 344 from Peabody's Steam Tables gives the 
mean specific heat of superheated steam from the temperature of 
saturation to various temperatures at several, pressures. 

Thus the mean specific heat of steam at 142.2 lb. pressure when 
superheated to 572° F. is .53. The heat required to raise one 
pound of steam from a saturation temperature of 354° to 572° is 
(572 - 354) .53 » 115.5 B. t. u. The total heat of the super- 
heated steam is the sum of this quantity and the heat in the satu- 
rated steam. See also Superheaters. 

Dry steam is steam that contains no moisture. 

Wet steam is steam containing intermingled moisture, mist or 

Digitized by VjiOOQIC 



344 



MACHINERY 



Kilograms 
























per square 


1 


2 


4 


6 


8 


10 


12 


14 


16 


18 


20 


centimeter 
























Pounds per 
























square inch 


14.2 


28.4 


56.9 


85.3 


113.8 


142.2 


170.6 


199.1 


227.5 


256.0 


284.4 


Temp. 








» 
















saturation 


99 


120 


143 


158 


169 


179 


187 


194 


200 


206 


211 


°C. 
























Temp. 
























saturation 
°F. 


210 


248 


289 


316 


336 


354 


369 


381 


392 


403 


412 


op 


°C. 
























212 


100 


.463 






















302 


150 


.462 


.478 


.515 


















392 


200 


.462 


.475 


.502 


.530 


.560 


.597 


.635 


.677 








482 


250 


.463 


.474 


.495 


.514 


.532 


.552 


.570 


.588 


.609 


.635 


.664 


572 


300 


.464 


.475 


.492 


.505 


.517 


.530 


.541 


.550 


.561 


.572 


.585 


662. 


350 


.468 


.477 


.492 


.503 


.512 


.522 


.529 


.536 


.543 


.550 


.557 


752 


400 


.473 


.481 


.494 


.504 


.512 


.520 


.526 


.531 


.537 


.542 


.547 



spray. It has the same temperature as dry saturated steam of 
the same pressure. 

Miscellaneous Notes. — The temperature of steam in contact 
with water depends upon the pressure under which it is generated. 
At the ordinary atmospheric pressure (14.7 lb. per square inch) its 
temperature is 212° F. As the pressure is increased, as by the 
steam being generated in a closed vessel, its temperature and that 
of the'water in its presence increases. 

Absolute zero is taken by different authorities as being from 
459.2° to 460.66° below the Fahrenheit zero. The value, 460°, is 
close enough for all engineering calculations. 

Steam Table. — The following table contains the properties of 
dry saturated steam. Column 1 gives the absolute pressure of the 
steam in pounds per square inch, the gauge pressure being 14.7 lb. 
less. Column 2 gives the corresponding temperature of the, steam 
in Fahrenheit degrees. Column 3 gives the heat of the liquid, or 
the heat necessary to raise one pound of water from 32° to the 
boiling point corresponding to the pressure. Column 4 gives the 
latent heat, or the heat necessary to change a pound of water at 
the temperature of the boiling point into steam at the same temper- 
ature. Column 5 gives the total heat of the steam, and is the 
sum of the quantities in Column 3 and Column 4. Column 6 is 
the volume of one pound of steam at the different temperatures. 
Column 7 is the weight of one cubic foot of steam at the different 
temperatures. 



Properties of Saturated Steam 



Abs. 
Pressure 


Temper- 
ature 
Degrees 


Heat 


Latent 
Heat 


Total 


Specific 
Volume 


Density 
Pounds 


Abs. 
Pressure 


Pounds 


of the 


of 


Heat of 


Cu. Ft. 


Pounds 


per 
Sq. In.* 


Liquid 


Evapora- 
tion 


Steam 


per 
Pound 


per 
Cu. Ft. 


per 
Sq. In. 


P 


t 


h 


L 


H 


V 


_i 

V 


P 


.0886 


32 





1072.6 


1072.6 


3301.0 


.000303 


.0886 


.2562 


60 


28.1 


1057.4 


1085.5 


1207.5 


.000828 


.2562 


.5056 


80 


48.1 


1046.6 


1094.7 


635.4 


.001573 


.5056 


1 


101.8 


69.8 


1034.6 


1104.4 


333.00 


.00300 


1 


2. 


126.1 


94.1 


1021.4 


1115.5 


173.30 


.00577 


2 . 


3 


141.5 


109.5 


1012.3 


1121.8 


118.50 


.00845 


3 


4 


153.0 


120.9 


1005.6 


1126.5 


90.50 


.01106 


4 


5 


162.3 


130.2 


1000.2 


1130.4 


73.33 


.01364 


5 


6 


170.1 


138.0 


995.7 


1133.7 


61.89 


.01616 


6 


7 


176.8 


144.8 


991.6 


1136.4 


53.58 


.01867 


7 


8 


182.9 


150.8 


988.0 


1138.8 


47.27 


.02115 


8 


9 


188.3 


156.3 


984.8 


1141.1 


.42.36 


.02361 


9 


10 


193.2 


161.2 


981.7 


1142.9 


38.38 


.02606 


10 


11 - 


197.7 


165.8 


978.9 


1144.7 


35.10 


.02849 


11 


12 


202.0 


170.0 


976.3 


1146.3 


32.38 


.03089 


12 


13 


205.9 


173.9 


973.9 


1147.8 


30.04 


.03329 


13 


14 


209.6 


177.6 


971.6 


1149.2 


28.02 


.03568 


14 


14.7 


212.0 


180.1 


97Q.0 


1150.1 


26.79 


.03733 


14.7 


15 


213.0 


181.1 


969.4 


1150.5 


26.27 


.03806 


15 


16 


216.3 


184.5 


967.3 


1151.8 


24.77 


.04042 


16 


17 


219.4 


187.7 


965.3 


1153.0 


23.38 


.04277 


17 


18 


222.4 


190.6 


963.4 


1154.0 


22.16 


.04512 


18 


19 


225.2 


193.5 


961.5 


1155.0 


21.07 


.04746 


19 


20 


228.0 


196.2 


959.7 


1155.9 


20.08 


.04980 


20 


21 


230.6 


198.9 


958.0 


1156.9 


19.18 


.05213 


21 


22 


233.1 


201.4 


956.4 


1157.8 


18.37 


.05445 


22 


23 


235.5 


203.9 


954.8 


1158.7 


17.62 


.05676 


23 


24 


237.8 


206.2 


953.2 


1159.4 


16.93 


.05907 


24 


25 


240.1 


208.5 


951.7 


1160.2 


16.30 


.0614 


25 


26 


242.2 


210.7 


950.3 


1161.0 


15.71 


.0636 


26 


27 


244.4 


212.8 


948.9 


1161.7 


15.18 


.0659 


27 


28 


246.4 


214.9 


947.5 


1162.4 


14.67 


.0682 


28 . 


29 


248.4 


217.0 


946.1 


1163.1 


14.19 


.0705 


29 


30 


250.3 


218.9 


944.8 


1163.7 


13.74 


.0728 


30 


31 


252.2 


220.8 


943.5 


1164.3 


13.32 


.0751 


31 


32 


254.1 


222.7 


942.2 


1164.9 


12.93 


.0773 


32 


33 


255.8 


224.5 


941.0 


1165.5 


12.57 


.0795 


33 


34 


257.6 


226.3 


939.8 


1166.1 


12.22 


.0818 


34 


35 


259.3 


228.0 


938.6 


1166.6 


11.89 


.0841 


35 


36 


261.0 


229.7 


937.4 


1167.1 


11.58 


.0863 


36 


37 


262.6 


231.4 


936.3 


1167.7 


11.29 


.0886 


37 


38 


264.2 


233.0 


935.2 


1168.2 


11.01 


0908 


38 


39 


265.8 


234.6 


934.1 


1168.7 


10.74 


.0931 


39 


40 


267.3 


236.2 


933.0 


1169.2 


10.49 


.0953 


40 


41 


268.7 


237.7 


931.9 


1169.6 


10.25 


.0976 


41 


42 


270.2 


239.2 


930.9 


1170.1 


10.02 


.0998 


42 


43 


271.7 


240.6 


929.9 


1170.5 


9.80 


.1020 


43 


44 


273.1 


242.1 


928.9 


1171.0 


9.59 


.1043 


44 


45 


274.5 


243.5 


927.9 


1171.4 


9.39 


.10C5 


45 


46 


275.8 


244.9 


926.9 


1171.8 


9.20 


.1087 


46 


47 


277.2 


246.2 


926.0 


1172.2 


9.02 


.1109 


47 


48 


278.5 


247.6 


925.0 


1172.6 


8.84 


.1131 


48 


49 


279.8 


248.9 


924.1 


1173.0 


8.67 


.1153 


49 


50 


281.0 


250.2 


923.2 


1173.4 


8.51 


1175 


50 


51 


282.3 


251.5 


922.3 


1173.8 


8.35 


1197 


51 


52 


283.5 


252.8 


921.4 


1174.2 


8.20 


.1219 


52 


53 


284.7 


254.0 


920.5 


1174.5 


8.05 


.1241 


53 



* To get the gauge pressure subtract 14.7 lbs. from the absolute. 

345 



Google 



Properties of Saturated Steam — Continued 



Aba. 
Pressure 


Temper- 
ature 
Degrees 
F. 


Heat 


Latent 
Heat 


Total 


Specific 
Volume 


Density 
Pounds 


Abs. 
Pressure 


Pounds 


of the 


of 


Heat of 


Cu. Ft. 


Pounds 


per 


Liquid 


Evapora- 


Steam 


per 


per 
Cu. Ft. 


„***? 


Sq. Im 




tion 




Pound 


Sq. In. 


V 


t 


h 


L 


H 


V 


V 


P 


54 


285.9 


255.2 


919.6 


1174.8 


7.91 


.1263 


54 


55 


287.1 


256.4 


918.7 


1175.1 


7.78 


.1285 


55 


56 


288.2 


257.6 


917.9 


1175.5 


7.65 


.1307 


56 


57 


289.4 


258.8 


917.1 


1175.9 


7.52 


.1329 


57 


58 


290.5 


259.9 


916.2 


1176.1 


7.40 


.1351 


58 


59 


291.6 


261.1 


915.4 


1176.5 


7.28 


.1373 


59 


60 


292.7 


262.2 


914.6 


1176.8 


7.17 


.1394 


60 


61 


293.8 


263.3 


913.8 


1177.1 


7.06 


.1416 


61 


62 


294.9 


264.4 


913.0 


1177.4 


6.95 


.1438 


62 


63 


295.9 


265.5 


912.2 


1177.7 


6.85 


.1460 


63 


64 


297.0 


266.5 


911.5 


1178.0 


6.75 


.1482 


64 


65 


298.0 


267.6 


910.7 


1178.3 


6.65 


.1503 


65 


66 


299.0 


268.6 


910.0 


1178.6 


6.56 


.1525 


.66 


67 


300.0 


269.7 


909.2 


1178.0 


6.47 


.1547 


67 


68 


301.0 


270.7 


908.4 


1179.1 


6.38 


.1569 


68 


69 


302.0 


271.7 


907.7 


1179.4 


6.29 


.1591 


69 


70 


302.9 


272.7 


906.9 


1179.6 


6.20 


.1612 


70 


71 


303.9 


273.7 


906.2 


1179.9 


6.12 


.1634 


71 


72 


304.8 


274.6 


905.5 


1180.1 


6.04 


.1656 


72 


73 


305.8 


275.6 


904.8 


1180.4 


5.96 


.1678 


73 


74 


306.7 


276.6 


904.1 


1180.7 


5.89 


.1699 


74 


75 


307.6 


277.5 


903.4 


1180.9 


5.81 


.1721 


75 


76 


308.5 


278.5 


902.7 


1181.2 


5.74 


.1743 


76 


77 


309.4 


279.4 


902.1 


1181.5 


5.67 


.1764 


77 


78 


310.3 


280.3 


901.4 


1181.7 


5.60 


.1786 


78 


79 


311.2 


281.2 


900.7 


1181.9 


5.54 


.1808 


79 


80 


312.0 


282.1 


900.1 


1182.2 


" 5.47 


.1829 


80 


81 


312.9 


283.0 


899.4 


1182.4 


5.41 


.1851 


81 


82 


313.8 


283.8 


899.8 


1182.6 


5.34 


.1873 . 


82 


83 


314.6 


284.7 


898.1 


1182.8 


5.28 


.1894 


83 


84 


315.4 


285.6 


897.5 


1183.1 


5.22 


.1915 


84 


85 


316.3 


286.4 


896.9 


1183.3 


5.16 


.1937 


85 


86 


317.1 


287.3 


896.2 


1183.5 


5.10 


. 1959 


86 


87 


317.9 


288.1 


895.6 


1183.7 


5.05 


.1980 


87 


88 


318.7 


288.9 


895.0 


1183.9 


5.00 


.2002 


88 


89 


319.5 


289.8 


894.3 


1184.1 


4.94 


.2024 


89 


90 


320.3 


290.6 


893.7 


1184.3 


4.89 


.2045 


90 


91 


321.1 


291.4 


893.1 


1184.5 


4.84 


.2066 


91 


92 


321.8 


292.2 


892.5 


1184.7 


4.79 


.2088 


92 


93 


322.6 


293.0 


891.9 


1184.9 


4.74 


.2110 


93 


94 


323.4 


293.8 


891.3 


1185.1 


4.69 


.2131 


94 


95 


324.1 


294.5 


890.7 


1185.2 


4.65 


.2152 


95 


96 


324.9 


295.3 


890.1 


1185.4 


4.60 


.2173 


96 


97 


325.6 


296.1 


889.5 


1185.6 


4.56 


.2194 


97 


98 


326.4 


296.8 


889.0 


1185.8 


4.51 


.2215 


98 


99 


327.1 


297.6 


888.4 


1186.0 


4.47 


.2237 


99 


100 


327.8 


298.4 


887.8 


1186.2 


4.430 


.2257 


100 


101 


328.6 


299.1 


887.2 


1186.3 


4.389 


.2278 


101 


102 


329.3 


299.8 


886.7 


1186.5 


4.349 


.2299 


102 


103 


330.0 


300.6 


886.1 


1186.7 


4.309 


.2321 


103 


104 


330.7 


301.3 


885.6 


1186.9 


4.270 


.2342 


104 


105 


331.4 


302.0 


885.0 


1187.0 


4.231 


.2364 


105 


106 


332.0 


302.7 


884.5 


1187.2 


4.193 


.2385 


106 


107 


332.7 


303.4 


883.9 


1187.3 


4.156 


.2407 


107 


108 


333.4 


304.1 


883.4 


1187.5 


5.119 


.2428 


108 


109 


334.1 


304.8 


882.8 


1187.6 


4.082 


.2450 


109 


110 


334.8 


305.5 


882.3 


1187.8 


4.047 


.2472 


110 



346 



y Google 



Properties of Saturated Steam — Continued 



Abs. 
Pressure 


Temper- 


Heat 


Latent 
Heat 


Total 


Specific 
Volume 


Density- 
Pounds 


Abs. 
Pressure 


Pounds 


ature 
Degrees 


of the 


of 


Heat of 


Cu. Ft. 


Pounds 


per 


Liquid 


Evapora- 


Steam 


per 


per 
Cu. Ft. 


per 


Sq. In. 




tion 




Pound 


Sq. In. 


P 


t 


h 


L 


H 


V 


± 

V 


P 


111 


335.4 


306.2 


881.8 


1188.0 


4.012 


.2493 


111 


112 


336.1 


306.9 


881.2 


1188.1 


3.977 


.2514 


112 


113 


336.8 


307.6 


880.7 


1188.3 


3.944 


.2535 


113 


114 


337.4 


308.3 


880.2 


1188.5 


3.911 


2557 


114 


114.7 


337.9 


308.8 


879.8 


1188.6 


3.888 


.2572 


114.7 


115 


338.1 


309.0 


879.7 


1188.7 


3.878 


.2578 


115 


116 


338.7 


309.6 


879.2 


1188.8 


3.846 


.2600 


116 


117 


339.4 


310.3 


878.7 


1189.0 


3.815 


.2621 


117 


118 


340.0 


311.0 


878.2 


1189.2 


3.784 


.2642 


118 


119 


340.6 


311.7 


877.6 


1189.3 


3.754 


.2663 


119 


120 


341.3 


312.3 


877.1 


1189.4 


3.725 


2684 


120 


121 


341.9 


313.0 


876.6 


1189.6 


3.696 


2706 


121 


122 


342.5 


313.6 


876.1 


1189.7 


3.667 


2727 


122 


123 


343.2 


314.3 


875.6 


1189.9 


3.638 


2749 


123 


124 


343.8 


314.9 


875.1 


1190.0 


3.610 


2770 


124 


125 


344.4 


315.5 


874.6 


1190.1 


3.582 


.2792 


125 


126 


345.0 


316.2 


874.1 


1190.3 


3.555 


.2813 


126 


127 


345.6 


316.8 


873.7 


1190.5 


3.529 


.2834 


127 


128} 


346.2 


317.4 


873.2 


1190.6 


3.503 


.2855 


128 


129 : 


346.8 


318.0 


872.7 


1190.7 


3.477 


.2876 


129 


130 


347.4 


318.6 


872.2 


1190.8 


3.452 


.2897 


130 


131 


348.0 


319.3 


871.7 


1191.0 


3.427 


.2918 


131 


132 


348.5 


319.9 


871.2 


1191.1 


3.402 


.2939 


132 


133 


349.1 


320.5 


870.8 


1191.3 


3.378 


.2960 


133 


134 


349.7 


321.0 


870.4 


1191.4 


3.354 


.2981 


134 


135 


350.3 


321.6 


869.9 


1191.5 


3.331 


.3002 


135 


136 


350.8 


322.2 


869.4 


1191.6 


3.308 


.3023 


136 


137 


351.4 


322.8 


868.9 


1191.7 


3.285 


.3044 


137 


138 


352.0 


323.4 


868.4 


1191.8 


3.263 


.3065 


138 


139 


352.5 


324.0 


868.0 


1192.0 


3.241 


.3086 


139 


140 


353.1 


324 5 


867.6 


1192.1 


3.219 


.3107 


140 


141 


353.6 


325.1 


867.1 


1192.2 


3.198 


.3128 


141 


142 


354.2 


325.7 


866.6 


1192.3 


£.176 
3.155 


.3149 


142 


143 


354.7 


326.3 


866.2 


1192.5 


3170 


143 


144 


355.3 


326.8 


865.8 


1192 6 


3.134 


.3191 


144 


145 


355.8 


327.4 


865 3 


1192.7 


3.113 


.3212 


145 


146 


356.3 


327.9 


864.9 


1192.8 


3.093 


.3233 


146 


147 


356.9 


328.5 


864.4 


1192.9 


3.073 


.3254 


147 


148 


357.4 


329.0 


864.0 


1193.0 


3.053 


.3275 


148 


149 


357.9 


329.6 


863.5 


1193.1 


3.033 


3297 


149 


150 


358.5 


330.1 


863 1 


1193.2 


3.013 


.3319 


150 


152 


359.5 


331.2 


862.3 


1193.5 


2 975 


.3361 


152 


154 


360.5 


332.3 


861.4 


1193.7 


2 939 


.3403 


154 


156 


361.6 


333.4 


860.5 


1193.9 


2.903 


.3445 


156 


158 


362.6 


334.4 


859.7 


1194.1 


2.868 


3487 


158 


160 


363.6 


335.5 


858.8 


1194.3 


2.834 


3529 


160 


162 


364.6 


336.6 


858.0 


1194.6 


2 801 


.3570 


162 


164 


365.6 


337.6 


857.2 


1194.8 


2.768 


.3613 


164 


166 


366.5 


338.6 


856.4 


1195.0 


2.736 


3655 


166 


168 


367.5 


339.6 


855.5 


1195.1 


2.705 


.3697 


168 


170 


368.5 


340.6 


854.7 


1195.3 


2.674 


.3739 


170 


172 


369.4 


341.6 


853.9 


1195.5 


2.644 


.3782 


172 


174 


370.4 


342.5 


853.1 


1195.6 


2.615 


.3824 


174 


176 


371.3 


343.5 


852.3 


1195.8 


2.587 


3865 


176 


178 


372.2 


344.5 


851.5 


1196.0 


2 560 


.3907 


178 


180 


373.1 


345.4 


850.8 


1196.2 


2.532 


.3949 


180 


182 


374.0 


346.4 


850.0 


1196.4 


2.506 


.3990 


182 



347 



y Google 



Properties of Saturated Steam — Concluded 



Abs. 
Pressure 


Temper- 
ature 
Degrees 
F. 


Heat 


Latent 
Heat 


Total 


Specific 
Volume 


Density 
Pounds 


Abs. 
-'ressure 


Pounds 


of the 


of 


Heat of 


Cu. Ft. 


Pounds 


per 


Liquid 


Evapora- 


Steam 


per 


per 
Cu. Ft. 


per 


Sq. In. 




tion 




Pound 


Sq. In. 


P 


t 


h 


L 


H 


t 


± 

9 


P 


184 


374.9 


347.4 


849.3 


1196.7 


2.480 


.4032 


184 


186 


375.8 


348.3 


848.5 


1196.8 


2.455 


.4074 


186 


188 


376.7 


349.2 


847.7 


1196.9 


2.430 


.4115 


188 


190 


377.6 


350.1 


847.0 


1197.1 


2.406 
2.381 


.4157 


190 


192 


378.5 


351.0 


846.2 


1197.2 


.4200 


192 


194 


379.3 


351.9 


845.5 


1197.4 


2.358 


.4242 


194 


196 


380.2 


352.8 


844.8 


1197.6 


2.335 


.4284 


196 


198 


381.0 


353.7 


844.0 


1197.7 


2.312 


.4326 


198 


200 


381.9 


354.6 


843.3 


1197.9 


2.289 


.4370 


200 


202 


382.7 


355.5 


842.6 


1198.1 


2.268 


.4411 


202 


204 


383.5 


356.4 


841.9 


1198.3 


2.246 


.4452 


204 


206 


384.4 


357.2 


841.2 


1198.4 


2.226 


.4493 


206 


208 


385.2 


358.1 


840.5 


1198.6 


2.206 


.4534 


208 


210 


386.0 


358.9 


839.8 


1198.7 


2.186 


.4575 


210 


212 


386.8 


359.8 


839.1 


1198.9 


2.166 


.4618 


212 


214 


387.6 


360.6 


838.4 


1199.0 


2.147 


.4660 


214 


216 


388.4 


361.4 


837.7 


1199.1 


2.127 


.4700 


216 


218 


389.1 


362.3 


837.0 


1199.3 


2.108 


.4744 


218 


220 


389.9 


363.1 


836.4 


1199.5 


2.090 


.4787 


220 


222 


390.7 


363.9 


835.7 


1199.6 


2.072 


.4829 


222 


224 


391.5 


364.7 


835.0 


1199.7 


2.054 


.4870 


224 


226 


392.2 


365.5 


834.3 


1199,8 


2.037 


.4910 


226 


228 


393.0 


366.3 


833.7 


1200.0 


2.020 


.4950 


228 


230 


393.8 


367.1 


833.0 


1200.1 


2.003 


.4992 


230 


232 


394.5 


367.9 


832.3 


1200.2 


1.987 


.503 


232 


234 


395.2 


368.6 


831.7 


1200.3 


1.970 


.507 


234 


236 


396.0 


369.4 


831.0 


1200.4 


1.954 


.511 


236 


238 


396.7 


370.2 


830.4 


1200.6 


1.938 


.516 


238 


240 


397.4 


371.0 


829.8 


1200.8 


1.923 


.520 


240 


242 


398.2 


371.7 


829.2 


1200.9 


1.907 


.524 


242 


244 


398.9 


372.5 


828.5 


1201.0 


1.892 


.528 


244 


246 


399.6 


373.3 


827.8 


1201 . 1 


1.877 


.532 


246 


248 


400.3 


374.0 


827.2 


1201.2 


1.862 


.537 


248 


250 


401.1 


374.7 


826.6 


1201.3 


1.848 


.541 


250 


275 


409.6 


383.7 


819.0 


1202.7 


1.684 


.594 


275 


300 


417.5 


392.0 


811.8 


1203.8 


1.547 


.647 


300 


350 


431.9 


407.4 


798.5 


1205.9 


1.330 


.750 


350 



Above table from Steam Tables, by Prof. C. H. Peabody. Definitions and for- 
mulae include abstracts from Prac. Marine Eng'g and Oil Fuel. 

Volume of Steam. — If water at boiling point (212° F) is evaporated 
into steam at atmospheric pressure, the volume of the steam will be 
1577 times the volume of the water from which it was evaporated. 
Or one cubic inch of water will produce nearly one cubic foot (1728 
cu. ins.) of steam. 



348 



Digiti 



zed by G00gk 



COAL CONSUMPTION 349 

Pounds or Gallons of Water Evaporated into Dry Steam per 
Pound of Coal. — Eight to ten pounds of water can be evaporated 
in well-designed boilers with good draft for every pound of bitumi- 
nous coal used. 

Example. The temperature of the feed water is 110°, the steam pressure 
150 lb., the thermal value of the coal used is 14,000 B. t. u. per pound, apd the 
efficiency of the boiler is .64. Find the pounds of water evaporated into dry 
steam per pounds of coal. 

From the steam tables the heat in the water at 212° at a pressure of 150 lb. 
gauge or 164.7 absolute (150 + 14.7) - 338 

Heat in the feed water (110° - 32°) = 78 

260 difference 
Latent heat of steam at 164.7 lbs. = 857 



Then heat required per pound of dry steam =1117. 

The heat available per pound of coal = .64 (efficiency of boiler) X 14,000 

8960 
B. t. u. = 8960. Hence pounds of steam evaporated = - - « 8.03. 

To convert 8.03 lb. of water into U. S. gallons divide by 8.33, as one U. S. gallon 
weighs 8.33 lb. 

o no 
Thus |^ = .96 gallon 
o.oo 

Pounds of Coal Required to Evaporate One Pound or One Gallon 
of Water into Steam. 

Let T = steam temperature, and t = feed water temperature 
Then units of heat = 1115 + .3 {T - t) 

Example. The steam pressure in a Scotch boiler is 160 lb. and the tempera- 
ture 370°. The feed water temperature is 140°. Find the units of heat required 
to evaporate one pound of water into steam, and the number of pounds of water 
evaporated by one pound of coal. 

Units of heat required per pound of coal = 1115 + .3 (370° — 140°) = 1086. 

Assume that one pound of coal gives out 9,000 units of heat (B. t. u.) 

9000 * 

Then -r~^ -= 8.28 lb. of water or .99 gallon are evaporated per pound of coal. 

Coal Consumption. — The coal required per indicated horse power 
per hour in good practice is between 1.5 to 2.0 lb. 

Let C = pounds of coal per i. h. p. per hour 

ff - i. h. p. 
C X H = pounds of coal per hour 



C XH 



tons of coal per hour 

24 XCXH CXH 



2240 
Then tons of coal per day of 24 hours = 



2240 93.3 

Formulae from Prac. Marine Eng'g and Verbal Notes, J. W. M. Sothera. 



360 MACHINERY 

As a quick estimate it may be assumed that a coal consumption 
of 1.S6 lb. per i. h. p. per hour (a figure only moderately good) the 
coal consumed per day will be 20 tons per 1000 i. h. p. See Marine 
Engines, paragraph To Calculate the Coal Consumption per i. h. p. 

Example. How many tons of coal will be required in the bunkers of a ship 
making a 7-day trip, with a coal consumption of 1.78 lb. per i. h. p., the engines 
being of 2,400 i. h. p., and a margin of 10% being allowed for emergencies. 

~ , j r i 24XCXH 3X1.78X2400 , B „- A 
Coal per day using formula — ^oln ~ 280 "* 

Coal for 7 days - 7 x 45.77 = 320 tons 
Margin 10% = 32 

352 tons required 

The rate of combustion in a furnace is computed by the pounds 
of fuel consumed per square foot of grate surface per hour. In gen- 
eral practice the rate for natural draft for anthracite coal is from 
7 to 16 lb., for bituminous from 10 to 25 lb., and with artificial 
or forced draft as by a blower, exhaust blast, or steam jet, the 
rate may be increased from 30 to 120 lb. Consumption of fuel 
averages 7K lb. of coal or 15 lb. dry pine wood per cubic foot of 
water evaporated. 

Fuel (Coal or Oil) Consumption* may be said to vary approx- 
imately as the horse power developed. The horse power varies 
as the cube (within certain limits) of the speed, hence it follows 
that the fuel consumption will vary approximately as the cube of 
the speed. 

Let S = certain speed of vessel 

C — coal or oil consumption at speed S 

8 — new speed 

c = coal or oil consumption at speed a 



m. «* X C A A */c X £» 

Then c = — ™ — and s = y — ^ - 

Example. A steamer consumes 100 tons of coal per day a\> a speed of 10 knots. 
What should be her speed if the Goal consumption were cut down to 50 tons a day. 

TT . .u r , //0<fS» */50 X 103 

Using the formula s = Af — jj— = A/ — =■== — = 7.9 knots 

Evaporation per Pound of Combustible. — It is often necessary 
to make an allowance for ash in the coal, or for the ash and mois- 
ture, so as to obtain the evaporation per pound of actual com- 
bustible matter. This is obtained by dividing the evaporation 
per pound of coal by the fraction of the coal which is combustible. 

* From Mariner's Handbook. 

Digitized by LiOOQ 1C 



HEAT VALUES OF COAL 



351 



The average multi-tubular boiler with coal evaporates 9 to 11 
lb. of water per pound of coal. With oil it evaporates 15 to 16.5 lb. 
of water per pound of oil. (See Factor of Evaporation.) 

3K to 4 barrels of oil are equivalent in boiler evaporation to 
one ton of coal. The average barrel of oil holds 50 to 51 gallons. 
See Oil 

Heat Values of Coal. — In anthracite coal the proportion of 
volatile matter varies from 3 to 10%, in semi-anthracite and semi- 
bituminous from 10 to 20%, and in bituminous from 20 to 50%. 
The amount of ash in good coal should not exceed 8 or 10%, although 
occasionally it is only 5%. 



Coal 


Fixed 
Carbon 


Volatile 
Matter 


B. t. u. per 

Pound 

of 

Combustible 


B. t.u. 

per 

Pound of 

Coal 


Anthracite, Pennsylvania, average 


84.25% 

51.17% 
73.65% 


5.62% 

34.04% 

18.30% 


14113 

14948 
15682 


12685 


Bituminous, Pennsylvania average 

of 28 samples 

Pocahontas (West Virginia 


13634 
14419 



From Oil Fuel. 

Calorific Value of Coal from its Chemical Analysis. — B. t. u. per 
pound of coal = 14600 C + 62000 (h - ^\ + 4000 S 

Where C, H y O and S are the proportionate parts by weight of 
carbon, hydrogen, oxygen and sulphur. Take for example a coal 
of the following composition (Pocahontas run of mine) : C = 85.4%, 
H = 4.39%, = 3.94%, S - 0.62%. 

Then B. t. u. per lb. = 14600 X .854 4- 62000 (.0439- -^jp) + 

4000 X .006 = 14910. 

As tested by a calorimeter this coal had actually a calorific value 
of 14906. The above formula is recommended by the American 
Society of Mechanical Engineers. 

Size of Coal 
Anthracite coal is graduated commercially as follows: 
Lump over bars set 3J^ to 5 ins. apart. 
Steamboat over 3J^-inch mesh and out of screen 
Broken over 2%-inch mesh, through 3j^-inch mesh 
Egg over 2 -inch mesh, through 2J£-inch mesh 

Stove over 1%-inch mesh, through 2 -inch mesh , 

Digitized by VjiOOQIC 



352 MACHINERY 

Chestnut over %-inch mesh, through 1%-inch mesh 
Pea - over }^-inch mesh, through %-inch mesh 

Buckwheat over %-inch mesh, through J^-inch mesh 
Rice over A-inch mesh, through J^-inch mesh 

Culm, slack, or screenings through A-inch mesh. 

Bituminous or soft coal is graduated as follows: 
Run of mine in fine and large lumps. 
Lump or Block goes through 6-inch screen or over. 
Egg goes over 3-inch mesh, through 6-inch 

No. 1 Roller Screened Nut over 2-inch mesh, through 3J^-inch 
No. 2 Roller Screened Nut over 13^-inch mesh, through 2-inch 
No. 3 Roller Screened Nut over 1-inch mesh, through lj^-inch 
No. 1 Washed Egg over 2-inch mesh, through 3-inch 

No. 2 Washed Stove over l}£-mch mesh, through 2-inch 

No. 3 Washed Chestnut over %-inch mesh, through lj^-inch 
No. 4 Washed over J^-inch mesh, through %-inch 

No. 1 Domestic Nut over 1 J^ or 2-inch mesh, through 3-inch 
No. 2 Nut over IJ^-inch mesh, through 2-inch 

No. 3 over jj-inch mesh, through 1 J^-inch 

Duff through J^-inch mesh. 
Screenings smallest sizes. 

Pocahontas Smokeless generally sized as Nut, Egg, Lump and 
Mine Run. 

Heat Values of Wood. — The average heat value of dry wood 
is 8,500 B. t. u. per pound, for wood with 25% moisture 6,000 B. t. u. 
and for 40% moisture 4,600. 

One Cord Air Dried Hickory or Hard Maple weighs about 4,500 

lb. and is equal to about 2,000 lb. coal. 
One Cord Air Dried White Oak weighs about 3,850 lb., and is 

equal to about 1,715 lb. coal. 
One Cord Air Dried Beech, Red Oak and Black Oak weighs about 

3,250 lb., and is equal to about 1,450 lb. coal. 
One Cord Air Dried Poplar (whitewood), Chestnut and Elm 

weighs about 2,250 lb., and is equal to about 1,050 lb. coal. 
One Cord Air Dried Average Pine weighs about 2,000 lb., and is 

equal to about 825 lb. coal. 
From the above it is safe to assume that 2\i lb. of dry wood is 
equal to 1 lb. average quality of soft coal, and that the full value 
of the same weight of different woods is very nearly the same — that 
is, a pound of hickory is worth no more for fuel than a pound of pine, 
assuming both to be dry. It is important that the wood be dry, 
as each 10% of water or moisture in wood will detract about 12% 
from its value as fuel. (Cord of wood a pile 4 ft. X 4 ft. X 8 ft.) 
Heat Value of Oil, see section on Oil. 

Digitized by LiOOQ 1C 



OIL 



353 



Temperature of Fire. — The following table from M. Pouillet 
will enable the temperature to be judged by the appearance of the 
fire: 



Appearance 


Temp. F. 


Appearance 


Temp. F. 


Red, just visible 

Red, dull 


997° 
1290 
1470 
1650 
1830 


Orange, deep 

Orange, clear 

White heat 


1830° 
2156 


Red, cherry dull 


2010 


Red, cherry full 


White bright 


2550 


Red, cherry clear 


White dazzling 


2910 



Quantity op Air Required for Combustion of Fuel 



Fuel 



Air per Pound 



Air per Kilogram 



Coke 

Coal (anthracite) . 
Coal (bituminous). 

Charcoal 

Lignite 

Peat, dry 

Wood, dry 

Petroleum 

Producer gas 



Cubic Feet 

162.06 
144.60 
143.40 
133.90 
112.43 
•92.36 

73.36 
172.86 

11.56 



Cubic Meter 
10.09 

9.01 

8.93 

8.53 

7.02 

5.75 

4.57 

10.76 

.72 



See also section on Draft. 



OIL 



Crude petroleum as it comes from the well varies in physical 
and chemical properties in different districts and countries and at 
different depths in the same district. It is nearly always lighter 
than water. The diagram below shows how by refinement the 
various oils are obtained. 

Crude Petroleum 



Products 



of Disl 



tillation 



Residua 



Benzine Lamp Oils 
(Commercial) 
Spirit 



Heavy Petroleum Oils 

(Olefiant Gas Oils) 

Gasoline 

(Motor Oils) 



Lubricating Oils Paraffin 
Asphaltum 



spl 
Pi 



itch 



Digiti 



zed by G00gk 



354 



MACHINERY 



Gravity 
deg. Be\ 



Flash Point 
deg. F. 



Burning Point 
deg. F. 



Crude oil 

Kerosene 

Distillate (gas oil) 

Fuel oil 

Residuum 



12 to 45 
40 to 50 
28 to 38 
22 to 28 
10 to 20 



110 to 200 
90 to 125 
100 to 250 
100 to 300 
125 to 500 



120 to 220 
105 to 150 
110 to 325 
125 to 375 
200 to 600 



Fuel Oil 
(60° F.) 



Specific 


Beaume 


Lb. per 
Am. Gal. 


Lb. per 


Cu. Ft. 


Gal. Amer. 


Gal. Eng. 


Bbls. 


Gravity 


Grav. 


Eng. Gal. 


per Ton 


per Ton 


per Ton 


per Ton 


1.0000 


10. 


8.331 


10. 


35.94 


268.875 


224. 


6.40 


.9956 


10.5 


8.302 


9.995 


36.09 


269.81 


224.75 


6.42 


.9930 


11. 


8.273 


9.930 


36.19 


270.76 


225.55 


6.44 


.9895 


11.5 


8.244 


9.895 


36.32 


271.71 


226.33 


6.46 


.9860 


12. 


8.214 


9.860 


36.45 


272.57 


227.13 


6.49 


.9825 


12.5 


8.185 


9.825 


36.57 


273.66 


227.96 


6.51 


.9790 


13. 


8.156 


9.790 


36.71 


274.62 


228.80 


6.54 


.9755 


13.5 


8.127 


9.705 


36.84 


275.62 


229.62 


6.56 


.9720 


14. 


8.098 


9.720 


36.97 


276.67 


230.49 


6.58 


.9685 


14.5 


8.069 


9.685 


37.10 


277.47 


231.16 


6.60 


.9655 


15. 


8.044 


9.650 


37.22 


278.46 


231.98 


6.63 


.9625 


15.5 


8.019 


• 9.625 


37.34 


279.33 


232.71 


6.65 


.9595 


16. 


7.994 


9.595 


37.46 


280.19 


233.42 


6.66 


.9560 


16.5 


7.964 


9.560 


37.59 


281.26 


234.31 


6.69 


.9530 


17. 


7.929 


9.530 


37.71 


282.22 


235.11 


6.74 


.9495 


17.5 


7.910 


9.495 


37.85 


283.08 


235.90 


6.75 


.9465 


18. 


7.885 


9.465 


37.97 


284.08 


236.66 


6.76 


.9430 


18.5 


7.856 


9.430 


38.11 


285.13 


237.52 


6.76 


.9400 


19. 


7.831 


9.400 


38.23 


286.04 


238.30 


6.81 


.9370 


19.5 


7.806 


9.370 


38.35 


286.95 


.239.06 


6.83 


.9340 


20. 


7.781 


9.340 


38.47 


287.88 


239.82 


6.85 


.9310 


20.5 


7.756 


9.310 


38.60 


288.88 


240.60 


6.87 


.9280 


21. 


7.730 


9.280 


38.73 


289.74 


241.34 


6.89 


.9250 


21.5 


7.706 


9.250 


38.85 


290.68 


242.16 


6.89 


.9220 


22. 


7.680 


, 9.220 


38.98 


291.62 


242.95 


6.94 


.9195 


22.5 


7.660 


9.195 


39.09 


292.42 


243.61 


6.96 


.9165 


23. 


7.635 


9.165 


39.21 


293.25 


244.40 


6.98 


.9135 


23.5 


7.615 


9.135 


39.34 


294.15 


245.21 


7.00 


.9105 


24. 


7.585 


9.105 


39.47 


295.31 


246.01 


7.03 


.9045 


. 25. 


7.536 


9.040 


39.73 


297.24 


247.64 


7.07 


.8990 


26. 


7.490 


8.990 


39.97 


299.06 


249.15 


7.08 


.8930 


27. 


7.440 


8.930 


40.24 


301.07 


250.84 


7.12 


.8870 


28. 


7.390 


8.870 


40.51 


303.11 


252.53 


7.21 


.8815 


29. 


7.344 


8.815 


40.77 


305.01 


254.00 


7.26 


.8755 


30. 


7.294 


8.755 


41.04 


307.10 


255.85 


7.31 


.8700 


31. 


7.248 


8.700 


41.31 


309.19 


257.47 


7.36 


.8650 


32. 


7.206 


8.650 


41.54 


310.85 


258.94 


7.40 


.8595 


33. 


7.160 


8.595 


41.81 


312.84 


260.61 


7.44 


.8545 


34. 


7.119 


8.545 


42.05 


314.65 


262.14 


7.40 


.8490 


35. 


7.070 


8.490 


42.32 


316.83 


263.83 


7.5t 


.8440 


36. 


7.031 


8.440 


42.58 


318.58 


265.40 


7.58 


.8395 


37. 


6.994 


8.395 


42.81 


320.27 


266.82 


7.62 


.8345 


38. 


6.952 


8.345 


43.06 


322.67 


268.42 


7.70 


.8295 


39. 


6.911 


8.295 


43.32 


324.12 


270.04 


7.71 


.8250 


40. 


6.873 


8.250 


43.56 


325.90 


271.51 


7.78 



y Google 



OIL BARRELS 355 

General Notes and Terms 
To find the weight of a gallon of oil multiply the weight of a 
gallon of water at 60° F. (8.328 lb.) by the specific gravity of the oil. 

Oil barrels are usually 21 ins. in diameter at the top and bottom, 
24 at the middle, 35 ins. high, and contain approximately 51 gallons. 
Weight of a barrel of oil = 51 gallons X weight of a gallon of oil 
which at 30° Beaume* is 7.29 lb. (see table) = 373 lb. plus the 
weight df the barrel or 70 lb. making a total of 443 lb. See page 20. 

A quick way to find the capacity of a barrel in Imperial gallom; 
use the formula .0014162 X length in inches X (diameter at middle 
in inches) 2 . To convert Imperial gallons into U. S. gallons multiply 
by 1.2. 

Heavy oils as fuel oils expand, when heated, about 1% for every 
25° of temperature, corrections being made to 60° F. If tem- 
perature' is above 60°, subtract, and if below, add. 

The density of an oil is specified in degrees Beaume* at a tem- 
perature of 60° F. For indicating the density an instrument called 
a hydrometer (having an arbitrary scale the readings of which are 
in degrees) is allowed to float freely in the oil. The Beaume* gravity 
value is then read at the point where the surface of the oil inter- 
sects the scale. 

Specific gravity is the ratio of the weight of a solid or liquid to 
an equal volume of water at f>0° F. To calculate the specific 
gravity of an oil at any temperature, having given its specific 
gravity at 60° F., take the number of degrees above or below 60° 
and multiply them by a constant which for heavy oils of 20° Beaume* 
and below is .00034, for those of 30° Beaume* .0004, of 30° to 40° 
Beaume* .00045, and for refined oil .00050. The product is to be 
added to or subtracted from the original specific gravity according 
as the temperature is below or above 60° F. 

For reducing Beaume* readings at 60° F. to specific gravity use the 
formula: 

140 
Specific gravity 



130 + degrees Beaum6 



Example. An oil at a temperature of 60° F., has a reading of 22 on the Beauine* 
scale. Find its specific gravity. 



140 
Specific gravity - ^ + g2 - .922 



Digiti 



zed by G00gle 



356 MACHINERY 

Specific Gravities and Weights op Various Oils 



Oil 



Specific 
Gravity 



Weight 
Pounds per 
Cubic Foot 



Vegetable oils 

Mineral lubricating oils 

Petroleum 

Petroleum, refined .... 

Benzine 

Gasoline 



.91— .94 
.90— .93 

.87 
.79— .82 
.73— .75 
.66— .69 



58 
57 s 
54 
.50 
46 
42 



Flash point of an oil is the lowest temperature at which the 
vapors arising therefrom ignite, without setting fire to the oil itself, 
when a small test flame is quickly brought near its surface and 
quickly removed. 

Fire point is the lowest temperature at which an oil ignites from 
its own vapors when a small flame is quickly brought near its sur- 
face and quickly removed. The fire point is about 50° above 
the flash point. * 

The viscosity of an oil is told by the number of seconds required 
for a certain quantity to flow through a standard aperture at con- 
stant temperatures, generally at 70°, 100° and 212° F. Gasoline 
is an example of a non-viscous oil. 

Color does not indicate the quality of an oil, neither does it 
show if it is suitable for any particular service. 

Chill or cold test is the lowest temperature at which an oil will 
pour. It gives no idea of the lubricating properties of an oil. 

Oil for Boilers. — Oil between 15° and 30° Beaume* is, as a rule, 
suitable for boilers. It should not be too heavy to be easily vapor- 
ized by a jet of steam or to cause trouble in cold weather, and 
not so light and volatile as to be flashy. 

With internally mixed burners where the oil and steam come 
together inside the burner it is necessary to maintain sufficient 
pressure of oil to overcome the back pressure of the steam and at 
the same time supply the proper amount of oil. This requires 
a pressure from 30 to 50 lb. With externally mixed burners, it is 
necessary to have only a pressure to insure the free passage of oil 
through the pipes, which is 4 to 5 lb. It is desirable in both types 
to heat the oil to a temperature of around 150° F. 

Heat Values of Oil. — 14 to 15 lb. of water are evaporated into 
steam from and at 212° F., per pound of oil. Assuming 15 lb., then 



nvJ^v^ 



FUEL OILS 367 

one horse power will be developed with 2.3 lb. of oil. The heat 
value of mineral oils and their products may be closely determined 
from their Beaume' gravity by the formula: B. t. u. per lb. ■= 
18650 + 40 (Beaume* gravity - 10). 



Per cent, of Total Steam Generated Used for 
Atomising Oil in the Burners 


Pounds of Steam for 
Atomising Oil per Pound 


1 


.15 


1.5 


.225 


2 


.30 


2.5 


.375 


3 


.45 


3.5 


.525 


4 


.60 


4.5 


.675 


5. 


.75 







Assume the average evaporation from and at 212° F. per pound 
of coal to be 7 lb., and for oil 15, then the ratio of evaporation 
is 7 to 15 and the pounds of oil equivalent to 2,000 lb. of coal will 
be 7 : 15 - x : 2000 or x - 933 lb., which divided by 373 (as- 
sume the oil in a barrel weighs 373 lb.) equals 2.5 barrels of oil as 
being equivalent to one ton (2,000 lb.) of coal, or 2.8 barrels to 
one ton of 2,240 lb. 

From one pound of crude oil there can be obtained from 1.6 to 
1.7 times as many British thermal units as from a pound of coal. 
In other words, one pound of oil is equivalent to 1.6 lb. of coal. 
If 34 to 35 cu. ft. of oil weigh a ton (2,240 lb.), assuming that 
42 cu. ft. of coal weighs the same amount, there is thus saved in 
stowage space with oil 15 to 20%. One ton of petroleum contains 
approximately 275 Imperial gallons or 360 U. S. gallons. 

Air required for the complete combustion of fuel oil is about 
200 cu. ft. per pound. 

Fuel Oils for Internal Combustion Engines. — Crude oil is only 
for Diesel engines, as electrically ignited engines will not run on it, 
but will on distillate, gasoline, and kerosene. See Internal-Com- 
bustion Engines. 

The Beaume* gravity is not always a true indication of the fuel 
value of the evaporization of an oil. The origin of the crude oil 
from which the fuel oil is obtained may also give rise to a vari- 
ation in its gravity without affecting its ease in evaporation. 

Digitized by VjiOOQLC 



358 MACHINERY 

A practical test which shows at once the volatility of liquid fuel, 
is the determination of the limits of its boiling point, which consists 
in observing: 

1. The initial boiling point. 

2. Per cent, of volume distilling over at several intermediate 

temperatures. 

3. The final boiling point. 

Gasoline (in England called petrol and in France essence) is 
a colorless inflammable fluid, the first and highest distillant of 
crude petroleum. The specific gravity ranges from .58 to .90 com- 
pared with the unit one assumed for water at 60° F. For every 
20° F. the specific gravity varies .01. Measured on the Beaume* 
scale higher specific gravities are denoted by lower numbers, and 
lower specific gravities by higher numbers without definite gradu- 
ations. 

Gasoline is not a simple chemical compound like water but a 
physical mixture of chemical compounds of carbon and hydrogen, 
each compound having different boiling points. In general, the 
higher the initial and final boiling points the more difficult will be 
the starting of an internal combustion engine on cold mornings, 
calling for the heating of the mixing chamber of the carbureter or 
the inlet air which passes to it. 

Lubricating Oil. — The desirable characteristics are: (1) the oil 
should possess cohesion ; (2) it should possess the maximum possible 
adhesion; (3) it should be as far as possible unchangeable; and 
(4) it should be commercially free from acid and be pure. 

Tests have shown conclusively that no one grade however high 
its quality is suitable for all types of steam and internal combustion 
engines, because of the different surfaces to be lubricated and the 
systems employed in feeding the oil. Hence from the engine 
builder should be obtained information on the oil that is best suited 
for his engine. 

In steam engines the amount of lubricating oil differs greatly, 
but from 5 to 8 lb. of oil per ton of coal may be taken as a fab- 
average, or say from 5 to 8 lb. per 1,000 i. h. p. per hour. In small 
high speed engines as in torpedo boats the above amounts are 
exceeded. 

Special oils are required for the cylinders of internal combustion 
engines on account of their high temperatures, ranging from 600° 
to 700° F. The oils must not only have good lubricating prop- 
erties, but should not leave behind any carbon. A carbon deposit 

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VARIOUS LUBRICATING OILS 



359 



and heavy exhaust smoke usually indicates that the oil is too light. 
The consumption of a light oil is much greater than a heavy. Under 
ordinary conditions the oil used for the bearings and for the cylin- 
ders should not exceed \ X A gallons per 1,000 i. h. p. in 24 hours. 

The viscosity of an oil may be increased by a thickener as oleate 
of alumina, but although a thickener brings up the viscosity it does 
give the greasiness expected when a particular viscosity was specified, * 
At ordinary temperatures, a very small quantity of oleate of alumina 
will considerably raise the viscosity of an oil. 

If an oil is to lubricate a bearing, it must be fluid enough at the 
temperature of use to flow readily into the bearing. Hence it is 
customary to chill samples of oil and to determine the temperatures 
at which they become too thick to flow readily. 

Uses and Characteristics op Various Lubricating Oils 



Kind of Oil and Use 



Gravity 
Beaume 



Flash 

Test 

Degrees F. 



Fire 

Test 

Degrees F. 



Viscosity 
at 70° F. 
(water =1) 



High pressure cylinder oils: for cyl- 
inders using dry steam from 110 to 
2101b 

General cylinder oil: for cylinders us- 
ing dry steam from 75 to 100 lb. 
Also for air compressor cylinders 
when the oil is made from steam re- 
fined mineral stock and has a vis- 
cosity of 200 

Wet cylinder oil:* for cylinders using 
moist steam, especially in compound 
and triple expansion engines 

Gas engine cylinder oilf 

Heavy engine and machinery oils: for 
heavy slides and bearings 

Wet service and marine oils$ 



25-24.5 



26-25.5 



25.8-25.3 
26.5 



30.5-29.5 

28 



600-610 



550-585 



560-585 
320 



400 
430 



645-660 



600-630 



600-630 
350 



440-450 
475 



175-205 



180-190 



150-185 
300 



170-175 
230 



* May contain 2 to 6% of refined acidless tallow oil in the high pressure oils and 
6 to 12 in the low pressure. 

t Neutral mineral oil compounded with soap. The soap will not decompose 
at high heat, and although not a lubricant serves as a vehicle for carrying some oil. 

t May contain 30 to 40% of pure strained lard oil. 

Notes on Lubricating Oil.* 

A mineral oil flashing below 300° F. is unsafe on account of 
causing fire. 

A mineral oil evaporating more than 5% in 10 hours at 140° F. 
is inadmissible as the evaporation creates a viscous residue or 
leaves the bearing dry. 

* Notes from "Animal and Vegetable Fixed Oils and Waxes. " C. R. A. Wright. 

Digitized by VjiOOQ 1C 



360 



MACHINERY 



The most fluid oil that will remain in its place, fulfilling all other 
conditions, is the best for all light bearings at high speed. 

The best oil is that which has the greatest adhesion to metallic 
surfaces and the least cohesion in its own particles, in this respect 
fine mineral oils are first, sperm oil second, neatsfoot oil third, 
and lard oil fourth. 

Consequently the finest mineral oils are best for light bearings 
and high velocities. 

The best animal oil to give body to fine mineral oils is sperm 
oil. Lard and neatsfoot oil may replace sperm oil when greater 
tenacity is required. 

The best mineral oils should have the following properties: 



Where Used 



Evaporating 

Temperature 

Degrees F. 



Flashing 

Temperature 

Degrees F. 



Steam cylinders 

Heavy machinery 

Light bearings and high ve- 
locities '. 



.880 
.871 



560 
443 

424 



680 
518 

505 



Mineral oils alone are not suited for the heaviest machinery on 
account of want of body and high degree of inflammability. 

Olive oil is foremost among vegetable oils as it can be purified 
without the use of mineral acids. The other vegetable oils ad- 
missible but far inferior, stated in their order of merit, are gingelly, 
groundnut, colza and cotton seed oils. 

No oil is admissible which has been purified by means of mineral 
acids. 

Oil Burning Systems. — When fuel oil has a flash point of not 
lower than 150° F. the oil bunkers may be on both sides of the 
boilers, or at the sides of the expansion trunk, or in tanks forward 
of the oil space. For oil having a lower flash point than 150° F. 
a different arrangement is required, the oil compartments being 
separated from the engine and boiler spaces by a cofferdam. When 
high flash oil is carried the fuel pumps for pumping the oil into 
the settling tanks and boilers are usually placed in the stokehold. 
When low flash, a special pump room is built in the boiler space abaft 
the cofferdam. This pump room is a watertight compartment, is 
tested by being filled with water to the top, and has no direct 
communication with the machinery space. It contains only the 
pumps and a ventilating fan (see Oil Carriers). 

' Digitized by VjOOQLC 




Digitized by VjOOQ LC 



362 MACHINERY 

The open system of piping to the oil burners, in which oil cir- 
culates all the time through the heater and burner pipes and back 
to the pump suction, is often preferable for marine installations 
to the dead end system in which the oil simply goes to the burners. 
The piping must be carefully erected, with no rubber gaskets or 
packings. 

For the U. S. Naval Service the oil piping is seamless drawn 
steel, with flanges expanded on. The joints are scraped and made 
up metal to metal. Manila paper gaskets are allowed on suction 
pipes. Screwed fittings are used on connections under % in. 

For merchant service extra heavy welded iron or steel pipe is 
used, with screwed joints and with extra heavy galvanized iron 
fittings. Flanges are screwed on the pipes and manila paper or 
cardboard is used for gaskets or special oilproof packing. Copper 
piping is not used, but brass and composition fittings and valves 
may be used. 

The suction piping should be large, the practice at Newport 
News Shipbuilding Co., Newport News, Va., for the velocity of 
Mexican oil through suction pipes is not over 20 ft. per minute, 
the oil being heated to reduce the viscosity to about 30° Engler. 
For discharge pipe lines 100 ft. per minute is allowable in small 
pipes, the viscosity being reduced to 15° Engler or lower. It is 
dangerous to use a fuel oil which, to reduce its viscosity 'sufficiently 
for mechanical atomization, has to be heated beyond its flash point. 

Below are brief descriptions of the Koerting, White, and Kermode 
oil burning systems. In the Koerting, the oil is atomized by 
mechanical action, it being forced by pumps through superheaters 
to the burners. On the way from the superheaters to the burners, 
the oil which is under high pressure and of the required temper- 
ature is strained. After straining it goes to burners which are 
fastened to adjustable air registers provided with air admission 
slides to regulate the air supply so as to secure a proper mixture 
of air and oil. 

The oil leaves the burners perfectly atomized and the air for 
combustion is carried to the atomized oil by the air registers that 
are so constructed as to cause the air to form an intimate mixture 
with the oil, thereby securing complete combustion. The Koerting 
system is placed on the market by Schutte and Koerting, Phila- 
delphia, Penn. 

In the White system (see Fig. 52) the burner is designed to break up 
or atomize the oil as fine as possible. This is accomplished by driving 

Digitized by vjOOQ 1C 



BOILERS 363 

the oil along a number of flutes or passages on a cone, and with- 
out retarding its velocity impinging it on a fine-angled cone, de- 
livering it from the orifice in a spray at a pressure of 60 lb. which 
can be reduced to 10, the spray being still fine enough to flame. 
The flame burns at about one inch from the burner due to the 
perfect mixture with the air, and complete combustion is obtained. 
The White system is installed by the White Fuel Oil Engineering 
Co., New York. 

In the Kermode system there are three. different types: (1) the 
pressure jet where the oil is atomized by pressure — with this type 
neither steam nor air is required to disintegrate the oil, it being 
effected by pressure that is brought to bear upon the oil fuel itself 
by means of a force pump; (2) the oil is atomized by air pressure; 
and (3) the oil is atomized by steam pressure. Before the oil 
reaches the burners it is heated and filtered. The use of com- 
pressed air in place of steam is more economical and generally hot 
air is to be preferred when the best results are desired. The Ker- 
mode system was brought out by Kermode's Ltd., Liverpool, Eng. 

BOILERS 

There are two types of boilers, one where the fire goes through 
the tubes (fire tube boiler) and the other where the water does 
(water tube boiler). Of the former the most common is the Scotch 
boiler shown in Fig. 53. Their usual proportions are as follows: 

Sectional area of tubes i to } the grate surface. 

Volume of combustion chamber 3 to 4 cu. ft. per square foot of 
grate surface. 

Grate surface 10 to 15 sq. ft. per i. h. p. 

Heating surface 2 to 15 sq. ft. per i. h. p. 

Ratio of heating surface to grate varies from 16 to 30. 

Steam volume .3 to .4 cu. ft. per i. h. p. 

Coal burned 15 to 35 lb. per square foot of grate surface per hour, 
or % to 1 lb. per square foot of heating surface per hour. 

Water evaporated 6 to 10 lb. per pound of coal, or 4 to 10 lb. 
per square foot of heating surface per hour. 

Sectional area of funnel \ to J grate surface. 

Scotch boilers may be built in 2,000 h. p. units or even larger. 

For weights, see page 000. 

A good boiler working under favorable conditions will absorb 85% 
of the heat generated by the fuel, but 75% is the usual average. 

Data from Prac. Marine Engineering. 

Digitized by LiOOQ 1C 



364 



MACHINERY 
Scotch Boilers 



Diameter, mean 

Length over end plates 

Working pressure, lb 

Rules on which designed 

Number of furnaces 

Diameter of furnaces, external 

Thickness of furnaces 

Number of combustion chambers 

Number of tubes 

Diameter of tubes 

Length of tubes 

Surface of tubes, sq. f t 

Total heating surface, sq. ft 

Grate area, sq. ft 

Thickness of shell, ins 

Diameter of shell rivets 

Pitch of shell rivets 

Tensile test of shell plate 

Thickness of top end plates 

Thickness of front tube plates 

Thickness of back plates 

Thickness of combustion chamber 

Weight as finished in tons 

Weight per 100 sq. ft. total heating surface 
in tons 




From Marine Eng'g Estimates. C. R. Bruce. 

The combustion chamber of a Scotch boiler should have a water 
space of at least 5 ins. between it and the end of the boiler. The 
space should be wider at the top than at the bottom, the chamber 
having a slope of about H in- per foot of depth. Measured hori- 
zontally they should be as deep as possible, 28 and 36 ins. seem to 
be the smallest limits for single- and double-ended boilers respec- 
tively. The depth is about 12 ins. greater than one-half the furnace 
diameter for single-end boilers, and for double-end it is about 
24 ins. greater. 

In boilers with two furnaces the ratio of boiler diameter- to 
furnace diameter is approximately as 10 to 3. Custom is equally 
divided as to leading the two furnaces into two combustion cham- 
bers or into one. In estimating the heating surface of a corrugated 
furnace assume it as a plain cylindrical furnace whose diameter 
is the mean diameter of the corrugations. For boilers with three 
furnaces, the ratio of boiler diameter to furnace is as 4 to 1. Usu- 
ally three combustion chambers are fitted. For boilers with four 
furnaces the ratio of boiler diameter to furnace is as 5 to 1. Com- 
bustion chambers are generally arranged so that the two central 
furnaces are led into one, and the two wing into separate chambers 
so there would be one large and two small combustion chambers. 

Digitized by VjOOQLC 



1 1 »j 

N 



I- ' 



•ii* 111 

^ * £ ^ 51 X 
*in «C * $ ^ 



* * J 



V > 



I If! 









^ 




365 



366 



MACHINERY 

Particulars of Single Ended Scotch Boilers 
Natural Draft 



Mean 
Internal 


Mean 
Length 


Mean 
Internal 
Diameter 

of 
Furnaces 


Width 
of Com- 
bustion 
Chamber 


Tubes 


Heating 
Surface 


Length 

of Fire 

Bars 


Grate 
Area 


Diameter 


Number 


Dia. 


Length 


13' 6» 
14' 0* 
14' 6* 
15' 0* 
15' 6* 
16' 0* 
16' 6* 


10' 3* 
10' 6* 
10' 6* 
10' 9* 
11' 0* 
ll'O' 
11'3' 


3'2» 
3'4» 
3' 6* 
3' 8* 
3'9M' 
3' 11* 
4'1* 


2'5M* 
2' 6* 
2' 6* 
2' 7H' 
2' 9* 
2' 9* 
2' 10* 


198 
204 
238 
254 
268 
280 
284 


3H' 

3H* 
3 V 

3H' 

3M* 


7'0* 

V 2' 

V 2' 

V 3* 

V 4* 
7' 4* 

V 6* 


1608 
1694 
1949 
2100 
2234 
2331 
2425 


5'9» 
6'0» 
6'0» 
6'0» 
6'0» 
6'0» 
6'0» 


54.6 
60.0 
63.0 
66.0 
68.2 
70.5 
73.5 



Forced Draft 



13' 6* 


ll'O' 


3' 2' 


2' 5H' 


322 


2H' 


V 9.' 


1986 


5'0* 


47.4 


14' 0* 


ll'O' 


3' 4' 


2' 6* 


345 


2H' 


7' 8* 


2098 


5'0' 


50.0 


14' 6* 


11'3' 


3' 6* 


2' 7* 


386 


2)4' 


7' 10' 


2390 


5' 3* 


52.5 


15' 0* 


11' 6' 


3' 8* 


2'IVS 


407 


2)4' 


8'0* 


2560 


5' 3' 


55.0 


15' 6* 


11'9' 


3'9H" 
3' 11* 


2' 9' 


425 


2H' 


8' 3* 


2749 


5' 3* 


56.87 


16' 0* 


12' 0' 


2' 9* 


482 


2H' 


8' 4' 


3111 


5' 6' 


58.75 


16' 6* 


12' 3' 


4'1' 


2'10K 


510 


2H' 


8' 6* 


3352 


5' 6' 


61.25 



Note. The boilers in the above list are fitted with three of Mormon's with- 
drawable furnaces, each leading into a separate fire box. The center line of the 
top row of tubes is about one third of tne boiler diameter from the top, which 
represents good practice for pressures from 140 to 190 lbs. For higher pressures, 
the steam' space may be reduced, and the heating surface increased. (Above 
table from Marine Eng'g Estimates. C. R. Bruce.) 



The locomotive type is shown in Fig. 54. Here the furnace is 
of a rectangular cross section, and is surrounded by the shell at 
the front, leaving on the sides a narrow space known as the water 
leg. When so constructed that there is a space at the bottom 
below the firebox, the boiler is known as the wet bottom type, 
and where there is no space, as in Fig. 54, the dry bottom. 

Fig. 55 is of a flue and return tube or leg boiler. The hot gases 
pass from the furnace through large tubes or flues to a combustion 
chamber at the farther end, returning through small tubes and 
thence through the uptake to the funnel. The furnace has a 
rectangular cross section, and the front end of the boiler is modified 
on the sides and bottom to correspond to this form. Water legs 
are formed on the sides of the furnaces and from them the boiler 
gets its name. When built with the front end having flat sides and 
a rounded top it is known as a wagon top boiler. 



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368 



MACHINERY 



Locomotive and leg boilers are installed in shallow draft vessels, 
such as excursion steamers, where a Scotch boiler on account of 
its large diameter would seriously interfere with the arrangement 
of the decks. 




Figure 55.-rLeg Boiler. 
From Prac. Marine Engineering. 

Water-Tube Boilers. — Here the grate lies below the tubes and 
frequently between the lower drums, while the tubes and drums 
are surrounded by a casing to prevent as far as possible the loss 
of heat by radiation. 

The feed water enters the upper drum, then flows down certain 
of the tubes to the lower drums from which the water enters the 
upflow or steam forming tubes that are surrounded by the hot 
gases from the grates. During the passage of the water upward 
it is partly converted into steam, and the mixture of steam and 
water issues from the upper ends of the tubes into the drum. Here 
the steam is separated and enters the piping to the engine or tur- 



nvJ^v^ 



THE YARROW BOILER 369 

bine, while the water mixes with that already in the drum and begins 
on another round. 

The Yarrow has straight tubes, while the Thomycroft, Normand 
and White-Forster have curved tubes. In the latter there is a 
center and side drums (see Fig. 56), the tubes being curved to a 
standard, radius and are interchangeable. Thus spare tubes can 
be carried in straight lengths and may be bent and cut as desired. 
The Yarrow, Thomycroft, Normand, and White-Forster boilers 
belong to the small tube type and have been installed in a large 
number of torpedo boats, destroyers, and other high speed steam 



Of the large-tube water-tube boilers the Babcock and Wilcox 
(see Fig. 57) is well known. The tubes forming the heating surface 
are divided into vertical sections and to insure a continuous cir- 
culation in one direction are placed at an inclination of 15° with 
the horizontal. Extending across the front of the boiler and con- 
nected to the upper ends of the headers by 4-inch tubes is a hori- 
zontal steam and water drum. As the upper ends of the rear headers 
are also connected to this drum by horizontal 4-inch tubes each 




Figure 56.— White-Forster Water-Tube Boiler. 

Digitized by 



Google 



370 



MACHINERY 



section is provided with an entirely independent inlet and outlet 
for water and steam. Placed across the bottom of the front header 
and connected thereto by similar 4-inch tubes is a forged steel box 
with a 6-inch square section. The box situated at the lowest 
corner of the bank of tubes forms a blow-off connection or mud 
drum through which the boiler may be completely drained. The 
distance traveled by the products of combustion in contact with 
the heating surface is about 16 ft. 

The weight of Babcock and Wilcox boilers including water, as 
built for naval vessels and mail steamers, for 250 lb. pressure is 
about 25 lb. per square foot of heating surface. 

Weight, and Space Occupied by Various Makes of Water- 
Tube Boilers 



















Weight 


















of Boiler 


















and 












Floor 


Outside 


Heating 


Water 


Make 


Name of Steamer 


Length 


Width 


Height 


Space, 
Sq.Ft. 


Dia.of 
Tubes 


Surface. 
Sq.Ft. 


per 
Sq.Ft. 
Heating 
Surface 
in Lb. 


Babcock and 


U. S. Battleship 
















Wilcox 


Utah 


9' ir 


18' 4i" 


13' 111* 


167.68 


2*4 4* 


5,359 


•23.79 


Babcock and 


U. S. Battleship 
















Wilcox 


New Hampshire 


1C 1* 


14' 10*' 


13' 21* 


149.98 


2* A 4* 


3,926 


•25.80 


Normand 


U. S. Torpedo 
Boat Destroyer 
















Thornycroft. . 


Trippe 

U. S. Torpedo 
Boat Destroyer 


12' 6* 


15' ir 


14' 2' 


188.60 


l'&H' 


4,780 


tl2.40 




Terry 


10' 9*" 


15' 2f 


12' H' 


164.30 


U'AH' 


4,500 


tl2.20 


White-Forster 


Torpedo Boat 
Destroyer 


















Mary ant 


9' 01' 


14' 8i* 


12' 8* 


133.30 


1*4 If 


4,500 


tl2.10 


Yarrow 


Torpedo Boat 
Destroyer 


















Sterrett 


12' 9' 


14' 2|* 12' 10* 


181.00 


l*Ali* 


4,500 


tl2.50 



• Includes grates— coal burning. From Steam, Babcock A Wilcox Co. 
t Oil burning— no grates. 



Comparison of Fire-Tube and Water-Tube Boilers. — Fire-tube 
boilers take longer to get up steam. For example, Scotch boilers 
require between five and six hours to raise steam after the fires 
are started, whereas water-tube require from 30 to 60 minutes. 
Then again fire-tube boilers are heavier than water-tube (see 
Weights). f 

Digitized by LiOOQ LC 



BOILER HORSE POWER 371 

Water-tube boilers can stand forcing, are suitable for high steam 
pressures, and can raise steam quickly. Their disadvantages are: 
a more rigid restriction of the feed to fresh water; the necessity 
of a greater regularity of feed; greater difficulty in dealing with 
leaky tubes; general sensitiveness to variation in the conditions 
of use; and perhaps they are not so durable or so efficient as Scotch 
boilers when on long voyages. Their maximum size is about 
1,000 h. p., while Scotch have been built to about 2,000. The 
above applies particularly to small water-tube boilers. Large-tube, 
as the Babcock and Wilcox, have many of the advantages of Scotch 
boilers, with the additional advantage of being able to raise steam 
much quicker, which is of the greatest importance in warships. 

Boiler Horse Power. — The evaporation of 34.5 lb. of water per 
hour from a feed water temperature of 212° F. into steam at the 
same temperature is a standard commercial boiler horse power 
and is considered as equivalent to the evaporation of 30 lb. of 
waiter per hour from a feed water temperature of 100° F. into steam 
at 70 lb. pressure. 

For finding the approximate boiler horse power in water-tube 
boilers divide the total heating surface in square feet by 10. In 
ordinary Scotch or leg boilers, multiply the area of the grate sur- 
face in square feet by 3, or divide the number of tons of coal burned 
per hour by 3J^. The results from the above formulae express the 
evaporative capacity of a boiler in horse power based on the evapo- 
ration of 30 lb. of water per horse power per hour. 

To Find the Boiler Horse Power Required for an Engine. 

Let i. h. p. = indicated horse power of the engine 
B. H. P. = boiler horse power required 
8 = water rate or steam consumption in pounds 

per L h. p. per hour 
e = ratio of steam required for the auxiliary ap- 

paratus, such as feed pumps, etc., and 
may be taken as 1.08 for condensing en- 
gines and 1.02 for non-condensing 

ThenB.g.P.- ffep 34 X 5 8Xc 

Example. Find the boiler horse power required to supply steam to a 600 h. p. 
compound condensing engine. 

From the table of steam consumption (see section on engines) 15 lb. of steam 
are consumed per i. h. p. 

Using the above formula 

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372 



MACHINERY 



B . H. P. - *'■*-» * ' Xc « 600 X15 X1.08 _ ^ 



34.5 



34.5 



The following is another example: 

Example. Find the size of boiler required for a fore and aft compound engine 
with cylinders 10 and 20 ins. diameter by 14 ins. stroke, cutting off at 10H-inch 
stroke, working pressure of boiler, 160 to 165 lb., piston speed, 600 ft. per minute. 

First determine the probable indicated horse power of the engine. The general 
formula for mean effective pressure (MEP) (theoretical) is: 




Figure 57.— Babcock and Wilcox Water-Tube Boiler. 

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FACTOR OF EVAPORATION 373 

MEP - pi i- (1 + log., n) — p. 
n 

where pi *- boiler pressure 

n = number of expansions 

pi * back pressure 

if pi ■ 160 lb. per sq. in. (boiler pressure) 

10 X 10 X x X 14 

n 5X5XtX 10.5 " 633 

and pi -» 4 lb. per square inch (assumed} 

then MEP - 160 X ~g (1 + log. J5.33) — 4 

-160 x^gd+l.OTM)— 4 

« 80.2 — 4 «■ 76.2 lb. per square inch. 

The ratio of theoretical mean effective pressure to probable mean effective 
pressure is about . 55 for the above type of engine, so that 

. . _ MEP X piston speed X area lower pressure cylinder 
P * * 33,000 

41.9 X600 X314. 



33,000 
A steam consumption including auxiliaries of 25 lb. per h. p. hour is reasonable 
for this type of engine used I — — — J and gives 239 X 25 - 6,000 lb. per hour 

approximately, as the evaporation of the boiler. The equivalent evaporation from 
and at 212° is 

Heat contents at 165 lb. X 6,000 1,196 X 6,000 



Heat contents at 212° 1 ' 150 



-» 6,200 lb. approximately 



Boiler horse power — »' e — 180. 
o4.5 

For Scotch boilers about 7 lb. of steam per square foot of total 
heating surface is as much as should be counted on, which would 

give -= — = 857 sq. ft., and allowing 35 sq. ft. of heating surface 

857 
per 1 sq. ft. grate, the grate area is -^r- = 24.5 sq. ft. Therefore, 

a Scotch boiler for the given conditions should have about 860 sq. 
ft. of heating surface and 24.5 sq. ft. of grate area. If forced draft 
is used it is probable that the horse power per square foot of grate 
area would be about 15, which would give a much smaller boiler. 

In designing large boiler plants it is generally considered suffi- 
cient to provide boiler horse power equal to one-half the indicated 
horse power of the engine. 

Factor of Evaporation for any given feed water temperature 

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374 MACHINERY 

and boiler pressure is calculated by dividing the total heat above 
32° F. in one pound of steam at the given pressure minus the total 
heat in one pound of the feed water above 32, by the latent heat 
of steam at 212° which is 970.4 B. t. u. , 

Example. A boiler evaporates 5,000 lb. of water at 77° F. into steam at 91 . 3 
lb. gauge pressure every hour. What is the boiler horse power? 

From the steam table, steam at 91 .3 lb. gauge pressure contains 1,187.2 B. t. u. 
per lb. above 32°. 

Water at 77° contains 77-32 = 45 B. t. u. per lb. above 32°. 

Then the factor of evaporation =» — — Q ' = 1 . 177 

5,000 lb. of feed water per hour multiplied by 1 . 177 = 5,885 lb. of water which 
would have been evaporated into steam with the same heat used to evaporate 
5,000 lb. from 77° into steam at 91.3 lb. if the feed water temperature had been 
212° and the boiler pressure lb. The equivalent evaporation from and at 212° is 
5,885 lb., and divided by 34 . 5 lb. gives 170 . 6 as the b. h. p. (From Oil Fuel). 

Boiler Efficiency is the ratio of the heat actually transmitted 
to the water in the boiler to the total heat developed by the com- 
bustion of the fuel. This is determined by the quantity of feed 
water fed to the boiler, amount of coal burned, steam pressure 
in boiler, and temperature of feed water. 

Example. In a boiler, 864 lb. of coal were burned per hour, the feed water 
entering the boiler 8,350 lb. per hour, temperature of feed water 100° F., and the 
steam was blown into the atmosphere at 275 lb. per square inch. Find the efficiency 
of the boiler. 

The calorific value of the coal used was 15,120 B. t. u. 

Total heat per pound of dry saturated steam at 275 lb.; calculated from feed 
water at 32° is 1,208.3 B. t. u. 

The heat added per pound of feed water leaving the boiler as dry steam at 275 
lb. - 1,208.3 - (100° - 32°) - 1,140.3 B. t. u. 

Hence the heat carried away by 8,350 lb. of steam is 1,140.3 X 8,350 = 9,521,505. 

The heat from combustion if 864 lb. of coal is burned is 864 X 15,120 = 13,063,- 
680 B. t. u. 

Then the boiler efficiency is ' ' go , = .73 nearly. 

lo,UOo,OoU 

The following is another example. Find the efficiency of a boiler when the 
evaporation from and at 212° is 7 lb. of water per 1 lb. of coal containing 12,000 
B. t. u. per pound. 

7 X 970.4 Gatent heat of steam) - 6,793 B. t. u. imparted to the water per 
one pound of coal. 

Then ^qqq = 56 or 56% efficiency. 

Efficiency of small tube water tube boilers — 58% 

Efficiency of large tube water tube boilers 63 to 70% 

Efficiency of Scotch boilers 68 to 80% 

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BOILER WEIGHTS 



375 



Approximate distribution of heat in a Scotch boiler burning 
20 lb. of coal per square foot of grate surface, the heating surface 
being 30 times the grate, is as follows: 

Absorbed by feed water 68% 

Wasted in funnel gases 24 

Wasted in unburned carbon in ashes 2 

Wasted by radiation, etc 6 

Total 100% 

The heat absorbed by the feed water, viz., 68%, represents the 
efficiency of the boiler. 

Boiler Weights, Scotch and water-tube, see Machinery Weights. 

Gallons op Water Evaporated per Minute in Boilers 
Based on 30 lb. or 34J^ lb. per horse power. To find the gallons 
per minute multiply boiler horse power by .069 when evaporation 
is 34.5 lb. per hour and .06 when evaporation is 30 lb. per hour. 





Gallons 


Gallons 




Gallons 


Gallons 


H. p. of 


per Minute 


per Minute 


H. p. of 


per Minute 


per Minute 


Boiler 


at 30 lb. 


at 34.5 lb. 


BoUf.r 


at 30 lb. 


at 34.5 lb. 




per H. p. 


per H. p. 




per H. p. 


per H. p. 


25 


1.5 


1.725 


300 


18.0 


20.7 


50 


3.0 


3.45 


325 


19.5 


22.4 


55 


3.3 


3.79 


350 


21.0 


24.15 


60 


3.6 


4.14 


375 


22.5 


25.87 


65 


3.9 


4.48 


400 


24.0 


27.6 


70 


4.2 


4.83 


450 


27.0 


31.0 


75 


4.5 


5.17 


500 


30.0 


34.5 


80 


4.8 


5.52 


550 


33.0 


37.7 


85 


5.1 


5.86 


600 


36.0 


41.4 


90 


5.4 


6.21 


650 


39.0 


44.8 


95 


5.7 


6.55 


700 


42.0 


48.3 


100 


6.0 


6.9 


750 


45.0 


51.75 


110 


6.6 


7.59 


800 


48.0 


55.2 


120 


7.2 


8.28 


850 


51.0 


58.6 


125 


7.5 


8.625 


900 


54.0 


62.1 


130 


7.8 


8.97 


950 


57.0 


65.5 


140 


8.4 


9.66 


1000 


60.0 


69.0 


150 


9.0 


10.35 


1100 


66.0 


75.9 


160 


9.6 


11.04 


1200 


72.0 


82.8 


170 


10.2 


11.75 


1300 


78.0 


89.7 


175 


10.5 


12.075 


1400 


84.0 


96.6 


180 


10.8 


12.42 


1500 


90.0 


103.5 


190 


11.4 


13.11 


1600 


96.0 


110.4 


200 


12.0 


13.8 


1700 


102.0 


117.3 


225 


13.5 


15.52 


1800 


108.0 


124.2 


250 


15.0 


17.25 


1900 


114.0 


138TC8 1 


275 


16.5 


18.97 


2000 


120.W tiZE 



376 MACHINERY 

Boiler Fittings and Accessories 



Fitting 


Location on Boiler 


Main stop valve 


On top 
On top 
On top 
On top 
End or side 


Auxiliary stop valve 


Steam to whistle 


Safety valve 


Gauge glass connections 


8^111*1 f-Ortk 


End " " 


Auxiliary feed check valve 


End " " 


Main feed check valve .... 


End " " 


Test cocks 


End " " 


Salinometer cock i 


End " " 


Blow down cock 


Bottom 


Drain cock 


Bottom 







Safety Valve. — To provide for the escape of the steam should the 
pressure in the boiler rise above the safe working limit for which 
the valve is set. The valve must be direct connected to the boiler 
without any intermediate valves or pipe bends. 
Where A = area of safety valve in square inches, per square foot 
of grate surface. 
W = pounds of water evaporated per square foot of grate 

surface per hour. 
P =* absolute pressure per square inch = working gauge +15. 
The size for U. S. Steamboat-Inspection Service is determined 

by the formula A = .2074 X ?• 

Whenever the area, as found by the above formula is greater 
than that corresponding to 4J£ ins. diameter, two or more safety 
valves, the combined area of which shall be equal at least to the 
area required, shall be used. This calls for a single Y fitting to 
the boiler with two valves, or to a twin valve. See Fig. 58. 

There are two types of safety valves: (1) where the steam acts 
on the area of the valve when closed; and (2) where the valve 
disk has an additional area not exposed to the steam when the valve 
is closed, but acted upon by the pressure of the steam when the 
valve opens. The former usually has a lever and weight, while 
the latter is spring operated and is known as a pop safety valve. 
Pop safety valves are extensively used in the marine field; an 
example is the Ashton (Ashton Valve Co., Boston, Mass.), as shown 
in Fig. 58. Ashton valves have a patent blow-back head forming 



JVJCJVIV^ 



STOP VALVE 



377 




Figure 58.— Pop Safety Valve (Aahton Valve Co., Boston, Mass.) 



a chamber inclosing the spring and protecting it from the steam. 
The spring chamber is vented at the top, thus the discharge from 
a number of valves may be piped together, and yet a valve will not 
be loaded with back pressure. If desired the pipe from the valve 
or valves may run down the inside of the hull to below the water 
line, thus giving a noiseless discharge. 

Stop Valve. — This valve is in the pipe leading from the boiler 
to the main steam .line to the engines, and thus controls the supply 
of steam from the boiler. In warships and often in merchant ships 
the stop-valve is a non-return valve, and is self-closing, for should 
the boiler be ruptured, the valve by closing would stop a sudden 
rush of steam from the other boilers. 

Feed Water Connections for a Scotch Boiler. — Feed water heaters 
are installed in all first class vessels, and the feed water enters 
the boiler at about 200° F. The customary practice is to discharge 



ile 



378 MACHINERY 

the water above the tubes just below the water level in the boiler, 
through two or more branches led over the tubes with the ends closed 
and the sides perforated with small holes, the combined area to 
be \Yt times the area of the feed pipe. In no case should the 
discharge terminate above the water level in the steam space, for 
the reason that it would produce excessive priming and also air 
hammer in the feed lines. Quantities of air pass into the boiler 
with the water at all times, which produces a certain amount of 
hammer in the line, and to overcome this an air chamber of ample 
capacity should be placed on the discharge side of the feed pump 
or in some convenient place in the feed line. 

The U. S. Steamboat-Inspection Rules require all boilers to have 
two feed connections, viz., main and auxiliary. Sometimes the 
auxiliary is connected only with the injectors and is seldom used 
except for supplying the boilers sufficiently to keep the auxiliary 
machinery running when the main units are shut down. The 
auxiliary discharge should be placed above the furnaces, preferably 
about halfway to the top row of tubes. 

Feed Check Valve. — The water from the feed pump goes to the 
boiler through the feed pipe, and at the boiler passes through the feed 
check valve, which is a screw-down, non-return valve, and enters 
the internal feed pipe (see above). A stop valve is always placed 
between the check valve and the boiler, so if necessary for exam- 
ination or repair the check valve may be shut off from communi- 
cation with the boiler. In water tube boilers the feed water enters 
the upper drum. 

Surface and Bottom Blows. — Cocks or valves and connecting 
pipes leading overboard are fitted for blowing the grease scum and 
mud sediment out of the boiler. The cross-sectional area of the 
bottom blow may be so proportioned ajs to give one square inch 
for every 5 tons of water contained in the boiler, with a larger 
area for small boilers. The area for the surface blow is the same as 
the bottom blow. 

Steam Gauges. — The steam pressure within the boiler, or rather 
the excess of pressure within over the atmospheric pressure, is 
shown by a gauge, which is generally of the type using a Bourdon 
tube. Steam does not enter the gauge nor does it come in contact 
with any of the working parts. The tube from the boiler is bent 
in a loop or U, which serves as a trap for the water condensed 
beyond this point. Thus the Bourdon tube and part of the con- 
necting pipe are kept filled with water, which in turn is acted on 

Digitized by VjOOQ IC 



FUSIBLE PLUGS 379 

by the steam, and the pressure is indicated without the actual 
presence of steam within the gauge. 

Water Gauge and Cocks. — The level of the water is shown by 
a vertical glass tube, the upper end being connected to the steam 
space and the lower to the water. The glass should be adjusted 
so that when the water is at the bottom, the water in the boiler is 
still 3 or 4 ins. above the level of the highest heating surface. Besides 
the gauge glass, small cocks are provided which, on opening, indi- 
cate the water level in the boiler. 

Boiler Circulators. — To improve the circulation of the water — 
particularly in Scotch boilers — circulators are installed. Of the 
types on the market the Ross-Schofield and the Eckliff are worth 
noting. The former consists of steel plates fastened to the out- 
side of the combustion chamber and extending to the back plate 
of the boiler. By means of these plates and hoods the direction 
of the current set up by the heating of the water and the motion 
imparted by the steam bubbles from the point of formation to the 
surface of the water are directed into a channel, and a longitudinal 
and elliptical flow of water takes place and is maintained as long 
as heat is being transmitted to the water. 

The Eckliff circulator is quite different. It consists of specially 
formed and constructed tubes bent to conform to the curved surfaces 
of the furnaces. These tubes run vertically from the bottom 
of the boiler to the tops of the furnaces, and then horizontally 
along the tops, being in contact, with the entire length of the furnace 
except for one foot at each end, where the tube is bent upward at 
an angle which causes the water to discharge directly against the 
tube sheet just above the furnace. The playing of the water against 
the plates prevents the cracking of the furnace flange or the com- 
bustion chamber plate at the point where the two are riveted 
together. 

Another device often installed is a hydrokineter. This comprises 
a steam jet and series of nozzles, and is placed near the bottom of 
the boiler, thus driving upwards the cold water that collects there 
and causing it to circulate. The steam required for its use is fur- 
nished by another boiler. 

Fusible Plugs. — Every boiler other than those of the water 
tube type shall be fitted with at least two fusible plugs. They 
must be so installed that the end of the banca tin on the water end 
of the plug is not less than one inch above the dangerous low water 
level. (See U. S. Steamboat-Inspection Rules,) 

Digitized by LjOOQ IC 



380 MACHINERY 

Injectors and Inspirators are for feeding water to the boiler 
both operating on practically the same principle, viz., the energy 
of the steam in a relatively large pipe is concentrated on a small 
jet of water, giving it a high velocity and pressure that is sufficient 
to overcome the boiler pressure, to open the check valves and 
to force the water into the boiler. 




WITT* iuPPLf TO mttiLEn 

Figure 59. — Injector (Penberthy Injector Co., Detroit, Mich.). 

An inspirator differs from an injector in the fact that it has two 
tubes, one for lifting the water and the other for forcing it into 
the boiler. An inspirator handling cold water with a short lift, 
will work through a range of over 200 lb., while with water at 100° F., 
and a small lift, it will work through a range of from 150 to 200 lb. 

The capacity of an injector should be about 30% in excess of the 
maximum requirement of the boiler. A boiler horse power is the 
evaporation of 30 lb. of water per hour, adding 30% to this; then 
the required injector capacity would be about 40 lb. or 5 gallons 
per hour for each boiler horse power. By multiplying the number 
of boiler horse power by 40 lb. or 5 gallons, the capacity of the 
injector in pounds or gallons is obtained. When the boiler horse 
power is not known it can be approximated. See paragraph on 
boiler horse power. 

With cold water and a moderate lift, say not exceeding 6 or 
8-ft., a good automatic injector will start up with 25 or 30 lb. steam 
pressure, and will work with little or no further adjustment over 
a range of perhaps 100 lb. pressure. With feed water at about 
100° the same injector would start at 30 or 35 lb. and would work 
up to about 100 lb. 

Working on the same principle as boiler injectors are bilge ejectors 
which are used in drainage systems, see page 611. 



Digitized 



by Google 



HYDROMETER 381 

Hydrometer. — The density of water can be determined by an 
instrument known as a hydrometer. This instrument is placed in 
the water to be tested and the distance it sinks noted, and readings 
made from a scale on the side. Average sea water contains about 
one part in 32 of solid matter, and hydrometers are usually gradu- 
ated relative to this as a unit. That is, 2 on the scale indicates 
twice as much solid matter relatively as sea water; 3, three times 
as much and so on; while indicates fresh water. The density of 
the water depends on its temperature so that the scale on the hy- 
drometer can only be used with the temperature that it is graded 
with, which is usually 200° F. Sometimes three scales are provided, 
viz., 190°, 200° and 210°. The water is drawn from the boiler 
into a slender vessel called a salinometer pot, into 'which after 
the water has cooled to the temperature (190°, 200°, etc.) on the 
scale of the hydrometer, the hydrometer is placed in it, and the 
density of the water determined. 

Superheaters may be classed: (1) separately fired, i. e., those 
using the hot gases from a source other than the furnaces of the 
main boilers; (2) those utilizing the gases from the boiler on their 
way to the stack; and (3) those utilizing the gases which have not . 
left the main boiler evaporating surface. The two latter are more 
popular than the first. 

The above classes may be divided structurally into the tubular, 
which requires the steam to pass through tubes for a greater part 
or all of its path during which heat is added, and the cellular, which 
requires the steam to pass through a chamber of irregular shape 
and to receive heat from gases flowing through tubes which pass 
through the steam chamber. 

An example of Class 2 as applied to a Babcock and Wilcox water- 
tube boiler is shown in Fig. 57. Here the superheater is placed 
in a box that is arranged to form a continuation of the first and 
second passes of the gases of combustion as they pass around the 
tubes of the boiler. In order that the steam as it passes through the 
superheater may be thoroughly exposed to the hot gases, removable 
baffles or division plates are put in the headers of the superheater, 
two in the upper header at one-quarter of the length from each end 
and one in the lower header at mid-length. The result of this 
location of the baffles is to force the steam as it goes through the 
superheater tubes to pass through the hot gases 8 times. The 
superheater tubes are 2 ins. in diameter and are arranged in groups 
of 4, accessible from a single handhole. 

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382 



MACHINERY 




Figure 60. — Foster Superheater. 



Fig. 60 is a return bend element with connection headers of a 
Foster superheater (Power Specialty Co., New York, N. Y.). Any 
number of these elements may be connected together, the number 
depending on the quantity of steam to be superheated, the amount 
of superheat and the temperature of the gases that will strike the 
elements. Each element consists of a seamless drawn steel tube, 
on the outside of which are cast iron gills or flanges close together, 
the mass of metal acting as a reservoir for heat. Inside of the 



nvJ^v^ 



TESTS OF STEAMERS 



383 



elements are wrought iron tubes centrally supported by knobs or 
buttons. These inner tubes are closed at the ends. A thin annular 
passage for the steam is thus formed between the inner and outer 
tubes, the steam clinging closely to the heating surface and is 
quickly heated. 

Of Class 3 is the Schmidt, which when applied to Scotch boilers 
consists of collector castings and a system of units or elements 
made of U-bent cold-drawn seamless steel pipes. The collector 
castings are placed in either a vertical or a horizontal position 
and located in the uptake end of the Jx>iler. The units are arranged 
in groups leading in and out of the uptake end of the boiler tubes 
and are expanded into flanges or collars which are in turn fastened 
to the collector castings. In joining the ends of the unit pipes 
to the collector castings one end of the pipe is in communication 
with the header from the boiler and the other with the steam pipe 
leading to the engine. Thus the steam in passing from the boiler 
to the engine must pass through the units in the tubes, where 
the superheating takes place. The most economical results are 



Tests op Steamers Equipped with Superheaters 





Engine 


I.h.p. 


Draft 


Fuel 


Super- 
heat in 
Degrees 


Type of 
Boiler 


Super- 
heater 


Name of Steamer 


Economy 

in 
Per cent. 


Per 
I.h.p. 


J.C. WaOaee 

U.S.S. M iehigan... 
U.S. S. Carolina... 
Odin 


Quad- 
ruple exp. 
Triple 

Triple 

Triple 
Quad. 
Triple 
Triple 
Triple 
Triple 


1,589 

16,016 

17,651 

900 
4,027 
2,005 
2,600 
1,600 
1,925 


Induced 

Forced 

Forced 

Natural 
Howden 
Howden 
Natural 
Howden 
Natural 


6.7 

12.8-15 
16.5 


1.646 

1.51 

1.395 

1.303 

1.29 

1.454 

1.322 

1.10 

1.20 


88 

85.7 

47.5 

2ii" 
266" 


Babcock 

A Wilcox 

Babcock 

A Wilcox 

Babcock 

A Wilcox 

Scotch 

Scotch 

Scotch 

Scotch 

Scotch 

Scotch 


Babcock 
A Wilcox 
Babcock 
A Wilcox 
Babcock 
A Wilcox 
Schmidt 


Port Lincoln* 

Port Augtuta 


Schmidt 
Schmidt 
Schmidt 




Schmidt 




Schmidt 







* Port Lincoln, steam pressure 220 lb., temperature of steam 600°. 
t Ferrona, steam pressure 180 lb., temperature of steam 580°. 
From Marine Steam. Babcock & Wilcox Co. 

obtained from the Schmidt superheater with a temperature of 
from 580° to 620° F. Between these temperatures it is claimed 
that in a quadruple expansion engine the consumption will be from 
10 to 12%, in triple expansion 12 to 18%, and in compound engines 



ile 



384 



MACHINERY 



from 18 to 25% less than in similar engines using saturated steam 
and operating under the same conditions. 

Superheated Steam, see section on Steam. 

Feed Pumps, see Pumps. 

Boiler Covering, see Insulating Materials. 

Ash Ejectors. — Here the ashes are dumped into a hopper having 
a pipe curved at the upper end to a large radius that passes through 
the side of the vessel above the water line. To the hopper is a 
water connection from a pump, and by turning on the water the 
ashes are discharged overboard. The gallons of water required 
to operate ash ejectors are about as follows: 



Size of discharge pipe 
Inches 

3^ 
6 



Gallons of water per minute 

required to operate 

120 to 180 

160 to 240 

210 to 360 




Figure 61.— Ash Ejector. 

Fig. 61 is of an ash ejector built by Schutte & Koerting, Phila., 
Pa. H is the hopper into which the ashes are emptied, and A is 
the cock for turning on or off the water. The valve L admits air 



yGoogk 



OPERATING 385 

only into the discharge pipe when the ejector is in operation and 
closes automatically when the discharge is stopped. 

Instead of the above, on large steamers the ashes are raised in 
bags by a small steam engine and then dumped overboard. 

Operating. — The amount of water fed to a boiler should be as 
uniform as possible. When getting under way open all the check 
valves to the same extent and test all the water gauges. The feed 
check valves should be adjusted afterwards to give the requisite 
uniform supply to each boiler. The feed stop valves should always 
be wide open when water is being fed into a boiler. 

As to the temperature of the feed water the U. S. Steamboat- 
Inspection Rules state: "Feed water shall not be admitted into 
any marine boiler at a temperature less than 100° F., and every 
such boiler except donkey boilers, shall have an independent aux- 
iliary feed appliance for supplying said boiler with water in addition 
to the usual mode employed, which auxiliary feed shall enter the 
boiler through an opening and a fitting which are entirely inde- 
pendent of the fitting and opening for the main feed." 

Should any difficulty be experienced in feeding a boiler, the 
combustion should be checked at once by closing the dampers and, 
if necessary, ash pit doors. Should the water get below the lowest 
try cock and out of sight, the fires should be extinguished and then 
hauled. 

Always deaden fires before hauling, which can be done by throw- 
ing on wet ashes. Fire extinguishers should be handy, which could 
be used in case of emergency. 

Firing. — The intervals between successive charging of furnaces 
should be such that only a moderate amount of coal, not more 
than three shovelfuls, is required at each charging to keep the 
fires at the required thickness. In the U. S. Navy this interval 
has been found to be between four and five minutes. The rate of 
firing should be regular and some system of time firing be adopted. 

The fires must be maintained at an even thickness. They 
should not be less than 6 ins. thick for natural draft, and may 
be increased to 12 ins. for heavy forced draft. The draft and air 
supply, as well as the thickness of the fires, should be regulated 
to suit the rate of combustion. 

With a strong draft and very fine coal, it is sometimes desirable 
to dampen the coal before firing it, to prevent its being carried up 
the smoke pipe before being consumed. 
The fires should be cleaned at regular intervals and the cleaning 

Digitized by VJiOOQLC 



386 MACHINERY 

• 

should be started as soon as the fires show a tendency to become 
dirty, usually within 12 hours after starting the fires. Fires should 
be cleaned one after another, with a regular interval of time be- 
tween. It is bad practice to clean several fires at practically the 
same time. 

Shutting Off Boilers. — Fires should never be hauled except to 
prevent damage to a boiler in case of emergency. When steam is 
no longer required, fires must be allowed to die out in the furnaces, 
with the dampers, furnaces, and ash pits closed. 

When a boiler is to be shut off, internal accumulations of dirt 
should first be removed by use of blow-out valves, and the boiler 
then pumped up again to the usual level, unless it needs emptying 
to carry out any repairs. Emptying by blowing down must never 
be resorted to. 

Boilers, when not under steam or open for examination, should 
be kept full of fresh water of between three and four per cent, of 
normal alkaline strength. The boiler should be pumped full 
within 24 hours of completion of steaming, and should be kept so 
until 24 hours before being required for steaming purposes. Even 
if the boiler is to be examined within a few days of completion 
of steaming, the water should not be allowed to remain at working 
height, but the boiler pumped full. 

When it is not practicable to keep idle boilers full of fresh water, 
they should be emptied, their interiors thoroughly dried out, and 
open trays as large as possible be filled to about half with quick- 
lime and introduced through the manholes into the upper and lower 
parts of the boiler. The boiler must then be closed airtight and 
special precautions taken to prevent any moisture entering the 
interior. 

Overhauling Boilers. — Whenever a boiler is laid up for a complete 
cleaning and overhauling the following operations should be carried 
out: 

Clean fireside and overhaul all furnace fittings, brickwork, baf- 
fling, and fire parts. 

Empty, open, and wash out the water spaces with fire hose. 

Clean and inspect the water side and overhaul zincs (if installed) 
and internal fittings. 

Rinse out with fresh water and close the boiler. 

Overhaul all valves, gauges, cocks, and other fittings. 

Examine and repair all parts of the lagging, casing, and seating. 

Apply hydrostatic test for tightness of valves, gaskets, etc. 

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CLEANING TUBES 387 

Test for tightness under steam, including tightness of casing, 
and adjust safety valves. 

Cleaning by Air Pressure. — For partially cleaning the fire side 
of boilers, put a comparatively heavy air pressure on the fire rooms 
shortly before the fires die out, opening the boiler dust doors but 
having ash pit and furnace doors closed- This cleans the tubes 
and casings. Close all Sources of air supply to the furnaces, and 
keep them closed until the boiler is cooled. The above can only 
be done when the wind is abeam. 

Precautions in Opening Steam Drum. — After the boiler is empty 
see that the steam stop, feed and blow valves, and any other valves 
or cocks by which steam or water can enter the boiler are closed. 
Insure a complete absence of pressure by opening the air cock 
and test and water gauge cocks. Take off the manhole plates 
and ventilate the boiler for a sufficient time to allow all foul air 
to escape, and let no one enter the boiler until it has been ascer- 
tained that the air is pure. Owing to the possibility of the presence 
of an explosive mixture of hydrogen and air in boilers fitted with 
zincs, the air in the boiler must be diffused before applying an open 
light. 

Washing Out Boilers.— Use a hose with water at a pressure of 
at least 50 lb. Take the hose into the steam drum and wash out 
the circulating tubes; that is, if the boiler is a water tube boiler. 
The washing out shoulo\ be done as soon as possible after emptying, 
and before the sediment left in the tubes, nipples, and boxes becomes 
hardened. 

Cleaning Tubes. — Clean the tubes with swabs, bristle brushes, 
wire brushes, or scrapers, unless their condition indicates the ne- 
cessity of using turbine cleaners. 

Hard scale containing much sulphate of lime and magnesium 
can be removed from the boiler tubes with a turbine water cleaner 
using water at a pressure of about 125 lb. per square inch. The 
following has given good results: 

Sal soda 40 lb. 

Catechu 5 lb. 

Sal ammoniac 5 lb. 

Boiling Out. — The amount of boiler compound to be used and 
the time required for boiling out depends on the nature and amount 
of the dirt present. If an inspection after 24 hours continuous 

Digitized by VjiOOQ 1C 



388 



MACHINERY 



boiling shows that the scale is still hard, the boiling should be con- 
tinued. 

In boiling out, introduce steam from another boiler to the lower 
part of the boiler, allowing the excess to blow off through the safety 
valves or air cocks at about 40 lb. pressure. If it is impracticable 
to use steam from another boiler, maintain very light fires and 
carry only enough pressure in the boiler *to insure circulation. If 
heavy fires are maintained there is danger of overheating a dirty 
boiler: 

Causes op Scale and Remedy 



Troublesome substance 


Trouble 


Remedy or Palliation 


Sediment, mud, clay, etc. . . 

Readily soluble salts 

Bicarbonates of lime,., mag- 
nesia, iron 


Incrustation 
Incrustation 

Incrustation 
Incrustation 

Corrosion 
Priming 
Corrosion 

Corrosion \ 
Corrosion 


Filtration; blowing off 
Blowing off 

Heating feed. Addition 


Sulphate of lime 


of caustic soda, lime or 
magnesia, etc. 
Addition of carbonate of 


Chloride and sulphate of 


soda, barium chloride, 
etc. 

Addition of carbonate of 


Carbonate of soda in large 
amounts 


soda, etc. 
•Addition of barium 


Dissolved carbonic acid and 
oxygen 


chloride, etc. 
Heating feed. Addition 


Grease (from condensed 
steam) 


of caustic soda, slaked 

lime, etc. 
Slaked lime and filtering 
Carbonate of soda 


Organic matter (sewage) . . . 


Substitute mineral oil 
Precipitate with alum or 
feme chloride and filter 



Operating and Overhauling oontain abstracts from pamphlet published by the 
U. S. Navy Department, also from Care of Naval Machinery. H. C. Dinger. 

DRAFT 

Natural draft is caused by the difference of weight in the heated 
air of the uptake and the cold air entering the furnace. To obtain 
a good draft the funnel and uptake temperatures must be between 
600° and 700° F., this temperature being necessary to bring about 
the required difference of weight of air. 

Digitized by LiOOQ 1C 



DRAFT 389 

Heat Absorbed in Creating Natural Draft. — The specific heat 
of the funnel gases is about .23, which means that to raise one 
pound of the gases 1° in temperature, .23 of the heat unit (B. t. u.) 
is necessary. The example given below shows the loss incurred 
by the generation of natural draft. 

Example. Cold air temperature 62°, uptake temperature 700° F., and allowing 
24 lb. of air per pound of coal: calculate the heat units per pound of coal used in 
producing the draft. 

700° — 62° = 638° increase of air temperature 

B. t. u. required - 638° X (24 + 1) X .23 - 3,668.5 

The quantity (24 + 1) =24 lb. of air +. 1 lb. of coal - 25 lb. of gases in 

all neglecting ash and clinker. 
Assume that 1 lb. of coal contains 14,500 B. t. u., or 100% 
Then 14,500 : 3,668.5 = 100% : x% and x - 25% 

Thus 25% of the heat units in each pound of coal are used up 
in producing the necessary difference in temperature of the funnel 
gases required to form a draft by difference of weight. 

For Increasing the Draft to a Boiler, one of four means may be 
employed: 

(1) Closed fireroom; air forced by blowers into the fireroom 
which is closed airtight except for the inlets to the furnaces. A 
static pressure of % to 3 ins. of water is maintained according to 
the rate of combustion required. 

(2) Closed ash pit; the air in the stoke hold is at the same 
pressure as the outside atmosphere, the air handled by the blowers 
is led through ducts, and after passing over tubes heated by the 
waste gases from the boiler the air is delivered to the ash pits under 
pressure. An allowance of 4.5 cu. ft. of air per minute at atmospheric 
temperature per pound of coal burned per hour is usually enough 
and represents the provision of 270 cu. ft. of air per pound of coal. 
A well known type of this system is the Howden. 

(3) Exhaust fan in uptakes or between them and the funnel. 
Represented by the Ellis and Eaves induced draft system, in which 
an exhaust fan draws the gases along the uptakes and discharges 
them into the funnel. Assuming that the products of combustion 
reach the fan at 550° F., a capacity of 9.33 cu. ft. of gases per 
minute per pound of coal burned per hour should be allowed, this 
being equivalent to 560 cu. ft. of gases per pound of coal. 

(4) Steam jets in the funnel. 

Data from Mechanical Draft, Am. Blower Co. 

Measurement of Draft. — Draft is measured by a U-shaped tube 
located in the fireroom, one end of* which is open to the air pres- 

* Digitized by v^iOOQIC 



390 



MACHINERY 



sure in the fireroom and the other connected by an iron pipe to 
the space under the grates. The difference between the two pres- 
sures causes the water to rise and fall in the tube. On the side 
of the tube is a scale with fractions of an inch marked. Instead of 
the U tube a steam gauge having a graduated scale from to 5 lbs. 
may be used for forced draft. 
A column of water 27.66 ins. high exerts a pressure of one lb. per 

sq. in. Thus if the reading is 3 ins., then the pressure of the draft 

3 
is 0>7 gg = .108 lbs. per sq. in. If the pressure at the fan is 2J^ 

ins., the pressure under the fire bars is about Y% in. 

Velocity Created When Am Under a Given Pressure Escapes 
Into the Atmosphere 



Pressure in 


Velocity of 
Air in Feet 


Pressure in 


Velocity of 


Pressure in 


Velocity of 


Inches 


Inches 


Air in Feet 


Inches 


Air in Feet 


Water 


per 


Water 


per 


Water 


per 


Gauge 


Second 


Gauge 


Second 


Gauge 


Second 


.1 


20.7 


1.5 


80.1 


2.9 


111.2 


.2 


29.3 


1.6 


82.7 


3.0 


113.0 


.3 


35.8 


1.7 


85.2 


3.1 


114.9 


.4 


41.4 


1.8 


87.7 


3.2 


116.7 


.5 


46,3 


1.9 


90.1 


3.3 


118.5 


.6 


50.7 


2.0 


92.4 


3.4 


120.3 


.7 


' 54.7 


2.1 


94.7 


3.5 


122.0 


.8 


58.5 


2.2 


96.9 


3.6 


123.8 


.9 


62.1 


2.3 


99.1 


3.7 


125.4 


1.0 


65.4 


2.4 


101.2 


3.8 


127.1 


1.1 


68.6 


2.5 


103.3 


3.9 


128.8 


1.2 


71.6 


2.6 


105.3 


4.0 


130.4 


1.3 


74.6 


2.7 


107.3 






1.4 


77.4 


2.8 


109.3 







From Mechanical Draft. B. F. Sturtevant Co. 

Air Required. — The amount of air admitted to the furnaces 
should be regulated so that little or no smoke issues from the stacks. 
To find out about the combustion get an Ellis tube and test a 
sample of the smoke gases for carbon dioxide. Perfect combustion 
produces about 16% carbon dioxide in the stack gases. If the 
instrument shows 14% the combustion is very good but if it drops 
to 6, there is either too much air going through or not enough. 
Another chemical is put in the tube and another sample tested 
for carbon monoxide. If over 3% shows, it is fairly certain that 
there is not enough air tinder the grate bars. If there is only * 

Digitized by VJiOOQlC 



, BLOWERS 



391 



trace of carbon monoxide then there is too much air. There are 
on the market recording devices which automatically take and 
test samples of stack gases and trace a curve, which on a large ship 
is a valuable index of how the firing is being done, and shows at 
what times the firing was bad. 

The actual amount of air passing into the furnaces is usually 
not less than 18 or 20 lb. per pound of coal and may considerably 
exceed this amount. At 12.5 cu. ft. per pound (that is, 12.5 cu. ft. 
of air weighs 1 lb.) this would give the volume of air required per 
pound of coal from 225 (18 times 12.5 cu. ft.) to 250 cu. ft. See 
table Quantity of Air Required for Combustion of Fuel. 

Blowers. — There are a number of types on the market having a 
variety of design of runners or wheels. One that has given excep- 
tionally good results is the Sirocco, which consists of long narrow 
blades on the periphery of a wheel, curved forward in the direction 
of rotation and mounted parallel to the shaft. The blowers are 
driven by electric motors, by high speed steam engines running 
at 250 to 700 r. p. m., or by steam turbines. See Ventilation. 




Figure 62. — Fan Rotor. 



On account of the high speed it is important that all parts be 
properly lubricated. The speed at which the blower is to run is 
regulated by the water tender and is governed by the air pressure 

Digitized by VjiOOQIC 



392 



MACHINERY 



that is to be maintained. The engines require a periodical adjust- 
ment of the working parts, and they should be tried at least once 
a month if the vessel does not ordinarily run on forced draft. Care 
must be taken that the doors of the casings, oil service, etc., are 
absolutely dust tight, and that no dust or dirt can get on the 
bearings. 

When two or more turbine-driven high speed fans are in the 
same fireroom, the speed of each fan must be practically the same 
to obviate the fans' working against each other. The fan speeds 
may be adjusted by a single valve at each turbine and all fans 
slowed down or speeded up, as conditions require, by the manipu- 
lation of one valve supplying steam to all the turbines. 

Below is an abstract from the specifications for 9 turbine units 
for the U. S. battleship California: "Each blower to be of the 
multivane, centrifugal cased double inlet type capable of dis- 
charging continuously with ease 23,000 cu. ft. of air per minute 
with an average pressure at the boiler fronts not exceeding 4 ins. 



Fans Built for Forced Draft Installations as Installed on 
Various Steamers 

(B. F. Sturtevant Co., Hyde Park, Mass.) 



Cubic 


Revolu- 




Diameter 




Feet per 


tions per 


Size of Fan 


of Wheel 


Driver 


Minute 


Minute 




Inches 




16,000 


400 


90 ins. 


54 


6X5 vertical single-cylinder 
5X4 vertical double-cylinder 


16,000 
'6,000 


475 


No. 9 multivane 


40 


350 


* 119 ins. 


66 


6X5 vertical single-cylinder 


18,000 


450 


100 ins. 


60 


6X5 vertical single-cylinder 


18,000 


450 


No. 9 multivane 


40 


6X5 vertical single-cylinder 


20,000 


325 


120 ins. 


72 


7X6 vertical tingle-cylinder 


25,000 


350 


120 ins. 


72 


7X6 vertical single-cylinder 


25,000 


325 


130 ins. 


78 


7X6 vertical single-cylinder 


25,000 


450 


No. 9 multivane 


40 


7X6 vertical double-cylinder 


30,000 


500 


No. 9 multivane 


40 


5X4 vertical double-cylinder 


30,000 


300 


140 ins. 


87 


8X8 vertical single-cylinder 


35,000 


400 


No. 10 multivane 


47 


8X7 vertical single-cylinder 


17,000 


900 


No. 6 multivane 


23 


20 h. p. electric motor 


23,000 


1,000 


No. 7 multivane 


28 


30 h. p. electric motor 


40,000 


700 


No. 8 multivane 


34 


45 h. p. electric motor 


20,000 


2,000 


No. 60 turbovane 


25 


Steam turbine 


20,000 


1,600 


No. 6 multivane 


23 


Steam turbine 


30,000 


1,500 


No. 80 turbovane 


39 


Steam turbine 



Where the size of the fan is given in inches the fan is always of the steel plate 
type. The diameter of the inlet on steel plate fans is about seven-tenths the 
diameter of the wheel and the diameter of the inlet on multivanes and turbovanes 
is about 85% of the diameter of the wheel. The outlet, while of rectangular form, 
generally has an area about equal to the inlet area. 

Digitized by VJiOOQLC 



MARINE STEAM ENGINES , 393 

of water. Each blower will be driven by a direct connected steam 
turbine, coupled direct to the fan shaft by a flexible coupling. 
The turbine to be of sufficient power to run the blower at full capacity 
with a steam pressure of 200 lb. gauge, but will be strong enough 
to run continuously at 280 lb. with 50° F. superheat and with a 
back pressure of about 10 lb. The steam consumption per brake 
horse power under operating conditions not to exceed 45 lb. per 
hour." 

Miscellaneous Notes 

The size of coal must be reduced and the depth of the fire increased 
directly as the intensity of the draft is increased s 

The frictiorial resistance of the surface of the funnel is as the 
square of the velocity of the gases. Ordinarily from 20 to 30% 
of the total heat of combustion is expended in the production of 
the stack draft, to which is to be added the losses by incomplete 
combustion of the gaseous portion of the fuel, and the dilution of 
the gases by an excess of air, making a total of fully 60%. 

One square foot of grate will consume on an average 12 lb. of coal 
per hour under natural draft. 

Temperatures. — 

Furnace temperature about 2600° F. . 

Combustion chamber 1500° F. 

Uptake 750° F. 

Funnel 600° F. 

In some torpedo boat destroyers the hatches to the fireroom 
are made with two doors, viz., an upper and a lower, so that the men 
on entering and leaving will not cause a loss of pressure in the fire- 
room. 

MARINE STEAM ENGINES 

Marine steam engines are of the vertical type for screw propul- 
sion, and beam or inclined for paddle wheel. The boiler pressure 
for compound engines is about 120 lb., for triple expansion 140 to 
180, and slightly higher for quadruple. With a main steam pipe 
of ample size and the throttle valve wide open, the initial pressure 
should not be much lower than 5 lb. below the boiler pressure. 
The mechanical efficiency of an engine is the ratio of the work 
available at the propeller or at the paddle wheel to the work done 
on the pistons, and is from 85 to 90%. 

Vertical Engines. — When their length must be kept at a minimum 

Digitized by vjOOQ 1C 



394 



MACHINERY 



a tandem arrangement of the cylinders may be adopted; thus a 
four-cylinder triple expansion engine may only have three cranks. 
The following table gives the ways the cylinders may be supported. 



Cylinder Supported By 


Condenser 


Class of Vessel 


Cast iron column on one side to 
condenser which forms part 
of frame, other side has steel 
columns to bed plate 


Part of frame 


Tugs and cargo 
steamers 


Cast iron A columns 


Separate from 
engine 


Passengers and 
cargo steamers 


Steel columns 


Separate from 
engine 


War vessels 



To get the maximum work from the steam it is expanded in two 
or more cylinders — sometimes in as many as four, as in quadruple 
expansion — but the general practice in large engines is to have them 
triple expansion with three cylinders; if with four, besides the high 
and intermediate there are two low-pressure, and with five there 
are one high, two intermediate and two low. 

The ratio of the volume of the high-pressure cylinder to the 
low in compound engines is about 1 to 4, and in triple expansion 
1 to 7 or 1 to 7.25, the ratio to the intermediate being about 2.9. 

The ratio of expansion is the ratio of the volume of the low- 
pressure cylinder up to the point of release and including the clear- 
ance to the volume of the high-pressure cylinder up to the point 
of cut-off including the clearance. Taking the high-pressure cyl- 
inder as one, then the ratio of expansion in compound engines 
ranges between 5 and 7; for triple expansion between 8 and 12; 
and for quadruple expansion between 12 and 15. 

The valve controlling the admission of steam to the high-pressure 
cylinder is generally of the piston type, to the intermediate a single- 
ported or double-ported slide valve, and to the low pressure a 
double-ported slide valve. The great advantage of a piston valve 
lies in the fact that it is perfectly balanced in regard to the steam 
pressure. 

The power developed in each cylinder depends on the cut-off 
of the steam by the valve. The total horse power can be altered 
by changing the high-pressure cut-off or the initial pressure. To 

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EXPANSION 



395 




Figure 63.— Piston Valve, 
cut down the horse power of an engine, it is considered more eco- 
nomical to cut off earlier in the high-pressure cylinder than to lower 
the initial pressure by throttling. (See table of Steam Used Ex- 
pansively, page 405.) 



Expansion, 


Cut-off and Back Pressure. 




Type of Engine 


Initial 
Pressure 
at Engine 
Absolute 


Nominal 
Expan- 
sions 


High 
Pressure 
Cut-off. 


Back Pressure 

in lbs. per sq. in. 

Low Pressure 

Cylinder 


Triple expansion naval 

Triple expansion merchant 

Quadruple expansion merchant . 


165 
to 
200 
165 
to 
185 
190 
to 
210 


6 
to 

9 
to 
12 
12 
to 
14 


.7 
to 
.8 
.65 
to 
.75 
.65 
to 
.75 


5 
to 
7 
5 
to 
6 
5 
to 
6 



(From Marine Engine Design, by Bragg.] 



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396 



MACHINERY 



The order in which the cranks pass the top center when the 
engine is going ahead, to a person standing forward and looking 
aft, is called the crank sequence. Crank sequences are given 
starting with the forward cylinder. Thus in a triple expansion en- 
gine with the cylinders arranged with the high pressure forward, 
then the intermediate, and then the low, the crank sequence is 
generally high pressure, intermediate pressure, and low pressure; 
and with a four-cylinder triple, high pressure, forward low pressure, 
intermediate pressure, and then low pressure. 

In compound engines the cranks are 90° apart; in three-cylinder 
triple 120°; and in a four-cylinder often 90°. ' Designers as far as 
possible endeavor to have each cylinder develop the same power, 
and by a suitable arrangement of the cranks and moving parts 
to have the engine balanced so that no parts are unduly strained 
or overloaded. 

The distance between the piston and the bottom or top of the 
cylinder at the end of the stroke is the linear clearance. This is 
usually about \i of an inch or so at the top and % of an inch at the 
bottom, the clearance always being more at the bottom to allow 
for the wearing down of the bearings. 

The general design of an engine depends on the trade in which 
the vessel is to engage. For torpedo boats and other craft where 




Figure 64.— Slide Valve. 



Digitized 



by Google 



PADDLE-WHEEL ENGINES 39? 

high speed is essential, engines running at 400 or more revolutions 
per minute are not uncommon. Here the cylinders have a compara- 
tively short stroke and there are at least four. For merchant Vessels 
revolutions are decreased, the stroke is longer, and the cylinders 
are larger per horse power developed. 

To secure economy in the consumption of steam and hence of 
coal, the steam, after leaving the low-pressure cylinder, passes 
into a condenser (see Condensers). In the case of surface conden- 
sers they often form part of the engine framing. The back pressure 
on the low-pressure piston for condensing engines is about 3 lb. 
per square inch absolute, and for non-condensing 18 lb. absolute. 

Paddle-wheel Engines. — These can be divided into two classes, 
viz., those driving steamers with the wheels on the side and those 
driving steamers with wheels at the stern. 

Side-wheelers either have the engines inclined with the connecting 
rods working directly on the crank shaft, or vertical with the con- 
necting rod connected to a walking beam from which is a rod that 
drives the wheel shaft. When the engines are inclined there are 
two or more cylinders and the steam works expansively. When 
vertical there is only one cylinder having a stroke of several feet. 
(See Excursion Steamers and Paddle Wheels.) 

Simple beam engines have double poppet valves, generally 
with fixed Stevens' cut-off and in some cases with adjustable Sickles' 
dash-pot cut-off. Double trip shafts for raising the main and 
exhaust valves are on the larger engines, one trip shaft being for 
hand use and the other for operation by steam, as may be desired. 
When the boat is maneuvering, or approaching or leaving a pier, 
the main valve eccentric gear is disconnected. 

The main valves of the inclined engines for paddle steamers 
are usually of the double-beat poppet type, although in some cases 
there is a balanced slide valve on the high-pressure and double- 
ported slide valves on the low-pressure cylinders. Stephenson 
link gear is usually employed although the Walschaert gear has 
given excellent results. Piston valves have been extensively used. 

The main air pumps may be worked by the main engines. The 
condensers, feed water heaters, filters, and auxiliaries are of the 
customary types 1 . While jet condensers, in combination with water 
purifiers, in the past have been installed mostly on the Great Lakes, 
in recent years surface condensers have been adopted. 

Stern-wheel vessels are largely used on the Mississippi and 
other western rivers in the United States, and on shallow rivers 

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398 



MACHINERY 




Figure 65. — Double-Ported Slide Valve. 



in Africa and South America. In the United States the engines 
have horizontal cylinders relatively small in diameter, with a long 
stroke. The peculiar feature is the valve gear, the valves being of 
the double-beat poppet form, and each cylinder (one on each side 

Digitized by VjiOOQIC 



VALVES 



399 



of the steamer) is provided with four, two for steam and two for 
exhaust, the valves being&perated by a cam mechanism. 

Valves. — Different types are shown in Figs. 63, 64, 65 and 66. 
The chief advantage of a piston valve is that it is perfectly balanced 
as regards the steam pressures which act upon it. Since a flat 
slide valve is forced against its seat by the pressure of the steam 
on its back (which pressure is equal to the difference between the 
pressure in the receiver and in the cylinder), there is a heavy f no- 
tional load to be overcome by the eccentric acting through the 
valve stem. To keep the heads of a piston valve tight, packing 
rings are provided. In some cases where a piston valve takes 




Figure 66.— Allan's Valve. 



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400 



MACHINERY 



steam on the outside the steam is led to the chest at one end only, 
and then passes to the other end through the inside of the valve. 
In such cases the body of the valve is hollow, and as large as pos- 
sible. 

Fig. 64 shows a single-ported valve that covers but one set of 
ports. 

Fig. 65 is a double-ported slide valve. With this valve the area 
of the port opening required may be obtained with a travel of 
valve only one-half that for a single-ported valve, or with the 
same valve travel twice the area of the port opening may be se- 
cured. It is for this reason that a double-ported valve is often 
selected when it is desired to obtain a relatively large opening with 
a small travel of the valve. 

Trick's or Allan's valve (Fig. 66) gives a much quicker opening 
and also a longer duration of full opening than a plain slide valve. 
It is often used on compound engines. 

A triple expansion engine with cylinders 16 H, 25 and 43 ins. 
in diameter by 30 stroke had the following valves: 



Cylinder 



Valve 



Size of Port Openings 



High 
pressure 



Intermediate 
pressure 



Low 

pressure 



Piston (Fig. 63) 



Slide (Fig. 64) 



Double-ported 
Slide (Fig. 65) 



Rectangular port openings spaced 
around a circle 7 ins. in diameter. 
The openings being 1% ins. high, 
with % in. of metal between them 

Port openings on cylinder starting 
at top of cylinder, 1J^ steam, 33/g 
exhaust, l l /& steam by 24 ins. 
wide. Valve faces, top 3J^, 
opening 5% f lower face 3% by 
24 ins. 

Port openings on cylinder starting 

at top iy 8 , iy 8 , ±y 2 , \y 8 and 1% 

by 3 ft. 5 ins. Valve face 3J4 
opening 2%. face 1J4, opening 
1%, face Zy 8) opening 7, face 3J/g, 
opening \% } face 1J4, opening 
2%, face 3M, by 3 ft. 5 ins. wide 



Lap and Lead. — Figs. 67 and 68 are sections through a slide valve 
and cylinder showing lap (Fig. 67) and lead (Fig. 68). 



y Google 



VALVE TRAVEL 



401 




In Fig. 67, A B steam lap = edge of valve extends over edge of, 

port on steamjaide 
C D exhaust lap = edge of valve extends over edge of 
port on exhaust side 
In Fig. 68, A B steam lead = distance port is uncovered to steam 
C D exhaust lead = distance port is uncovered for 
exhaust. 
Valve Travel. — The travel of a valve is equal to (steam lap -f 
port opening) X 2. The following data is of a cargo steamer 



with an engine 



27 X 46 X 76 

48 



, 2360 i. h. p., high pressure receiver 



180 lb., intermediate 55 lb., low pressure 16 lb., r. p. m. 63, vacuum 
27 ins., speed 11.2 knots. 



Expansion 


Valve 
Travel 


Lead 


Steam Lap 


Port Opening 


CutrOff 


Top 


Bottom 


Top 


Bottom 


Top 


Bottom 


Top 


Bottom 


HIGH, PRESSURE PISTON VALVE 


Ins. 
.72 (full gear) 7 


v« 


% 


1A 


VA 


l»Vi« 


2 


Z5H 


33H 



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402 



MACHINERY 





Valve 
Travel 


Lead 


Steam Lap 


Port Opening 


CuWJff 


Expansion 


Top 


Bottom 


Top 


Bottom 


Top 


Bottom 


Top 


Bottom 


INTERMEDIATE PRESSURE DOUBLE-PORTED SLIDE VALVE 


.65 (full gear) 


6 


H 


K 


m 


1H 


m 


IX- 


33tf 


29K 


LOW PRESSURE DOUBLE-PORTED SLIDE VALVE 


.53 (full gear) 


8 


H 


A 


2H 


2A 


IX 


1* 


2SH 


22H 



Abstracts from Verbal Notes. J. W. M. Sothern. 

Valve Mechanism. — The most satisfactory valve mechanism 
for vertical marine steam engines is the Stephenson. With it the 
direction of rotation of the engine may be changed at will, and the 
point of cut-off varied by varying the travel of the valve. 

The Stephenson valve mechanism or link motion consists of 
two eccentrics, viz., ahead and astern, with a link connecting the 
ends of the eccentric rods that are fastened to the eccentric straps 




Figure 68.— Lead. 



Digiti 



zed by G00gk 



SLIDE VALVES 



403 



on the engine shaft, so that by varying the position of the link the 
valve stem may be put in direct connection with either eccentric 
or may be given a movement controlled partly by one eccentric 
and partly by the other. When the link is moved by suitable levers 
into a position such that the block to which the valve stem is at- 
tached is at either end of the link, the valve receives its maximum 
travel and when the link is in mid-position the travel is the least 
and the cut-off takes place early in the stroke. 

The expression "open and crossed eccentric rods" is under- 
stood to mean the position of the eccentric rods when the crank 
is on the bottom center, as in running the rods open and cross each 
other alternately. For slide valves or outside steam piston valves 
the rods are usually arranged as open, but with inside steam piston 
valves the rods are fitted so that they are crossed when the crank 
is on the bottom center. This is to obtain the full benefit of link 
expansion, for if the rods were arranged the reverse way the lead 
would be diminished when linked up, and the range of expansion 
more limited. 



Effects of 


Linking Up (Slide Valves) 




Arrangement of Eccentric Rods 


Valve 
Travel 


Lead 


Cut-Off 


Release 


Com- 
pression 


Open rods (crank on bottom) 

Crossed rods (crank on bottom) . . . 


Reduced 
Reduced 


Increased 
Decreased 


Earlier 
Earlier 


Earlier 
Earlier 


Earlier 
Earlier 



The disadvantages of Unking up are: excess wire drawing of 
steam, due to reduced port opening, and rapid increase of com- 
pression, which reduces the effective area of the indicator diagram. 

In the ordinary shifting link with open rods, the lead of the 
valve increases as the link is moved from full to mid-position, that 
is, as the period of steam admission is shortened. The variation 
of lead is equalized for the front and back strokes by curving the 
link to the radius of the eccentric rods concavely to the axes. With 
crossed eccentric rods the lead decreases as the link is moved from 
full to mid-position. 

The linear advance of each eccentric is equal to that of the valve 
in full gear, that is, to the lap plus the lead of the valve when the 
eccentric rods are attached to the link in such position as to cause 
half the travel of the valve to equal the eccentricity. 

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404 MACHINERY 

The angle between the two eccentric radii, that is, between 
lines drawn from the center of the eccentric disks to the center 
of the shaft, equals 180° less twice the angular advance. 

Setting of Valves, — Whether a valve is properly set or not can be 
readily told by taking indicator cards (see Indicator Cards). Many 
engines are supplied with steel laths marked with the setting of the 
valves and these are used to verify the position of the valves. 

To measure the lead of a valve, put engine on center with link 
in full gear and measure the steam port opening for that end. If 
this distance corresponds with the lead given on the drawing, the 
valve is set as designed. The cylinders of large engines have 
peepholes covered with bolted plates, by removing which the valves 
may be observed. A long thin wooden wedge is inserted in the 
opening as far as it will go, the edges of the opening leaving a mark 
on the wedge which is the measure of the lead. When the marks 
left by either end are alike the leads are alike. ' 

Owing to the wear on their collars, valves will drop, thus de- 
creasing the lead at one end, and increasing it at the other. If 
the valve takes steam on the outside, a dropping down of the valve 
will increase the lead on top and decrease it at the bottom. 

To bring the valve up into the proper position, distance pieces 
may be put above the shoulder of the valve stem, or liners placed 
under the valve stem. This takes into account the dropping 
down of a valve due to wear, and hence the shortening of the valve 
stem. Valves may also be changed by shifting the nuts holding 
the valve. 

To Find the Steam Pressure in a Cylinder at the End of the 
Stroke. — Boyle's law states that the pressure of a gas varies in- 
versely as the volume if kept at a constant temperature. 

Let P = absolute pressure in pounds 
V = volume in cubic feet 
C = constant 

Then PXV = C)P = y y V = y 

Example. The initial pressure in the high pressure cylinder of an engine is 185 
lb. gauge pressure, the cut-off . 6. Find the theoretical pressure at the end of the 
stroke. 

P = 185 +15 (atmospheric pressure) = 200 lb. 

C = P X V = 200 X .6 = 120 lb. 

C 120 
Then the absolute pressure P 2 = -— = — - = 120 lb., and 120 — 15 lb. (atmoa- 
Vi 1 

pheric pressure) =» 105 lb. gauge pressure. 

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STEAM CONSUMPTION 405 

Table of Steam Used Expansively 



Initial 


Average Pressure of Steam in Lb 


. per Square 
t Which Ste 


j Inch for the Whole 


Pressure 


Stroke. Portion of Stroke a 


,am is Cut Off. 


Lb. per 














Square 














Inch 


H 


H 


M 


H 


X 


Vs 


30 


28.9 


27.5 


25.4 


22.2 


17.9 


11.5 


35 ' 


33.8 


32.1 


29.6 


25.9 


20.8 


13.4 


40 


37.5 


36.7 


33.8 


29.6 


23.8 


15.4 


45 


43.4 


41.3 


38.1 


33.3 


26.8 


17.3 


50 


48.2 


45.9 


42.3 


37. 


29.8 


19.2 


60 


57.8 


55.1 


50.7 


44.5 


35.7 


23.1 


70 


67.4 


64.3 


59.2 


52.4 


41.7 


26.9 


80 


77.1 


73.5 


67.7 


59.3 


47.7 


30.8 


90 


86.7 


82.6 


76.1 


66.7 


53.6 


34.6 


100 


96.3 


91.8 


84.6 


74.1 


59.6 


38.4 


110 


106. 


101. 


93.1 


81.5 


65.6 


42.5 


120 


115.2 


110.2 


101.5 


89.4 


71.5 


46.1 


130 


125.4 


119.1 


110. . 


95.3 


77.5 


50. 


140 


134.9 


128.6 


118.5 


103.8 


83.3 


53.8 


150 


144.7 


137.8 


126.4 


111.2 


89.4 


57.7 


160 


153.6 


147. 


135.4 


118.2 


95.4 


61.5 


180 


173.5 


164.6 


152.3 


132.9 


107.3 


69.2 


200 


192.7 


183.7 


169.3 


148.3 


119.3 


76.9 



To Find the Number of Expansions by Pressures and by Volumes. * 

,„ . Hieh-pressure initial pressure absolute , - 

(1) ^ — - — r = — f u — r~r - number of expan- 

Low-pressure terminal pressure absolute 

sions by pressures. 

, rt . Low-pressure ratio , - , ' 

(2) „. , — „ = number of expansions by volumes 

High-pressure cut-off ^ J 

Example. Find the total number of expansions by pressures in a triple expan- 
sion engine, if the high-pressure cylinder has an initial pressure of 165 lb. (gauge) 
and the low-pressure cylinder a terminal pressure of 12 lb. absolute. Also the 
number of expansions by volume if the cylinder ratios are 1:2.7:7.2, and the 
high-pressure cut-off is r 6 

166 lb. + 15 lb. (atmospheric pressure) =■ 180 lb. abs. 

,, .„. High-pressure initial pressure absolute 180 - 

By (1) = 7~zr- — i , , . = -T7T - 15 expansions by pressure. 

Low-pressure terminal pressure absolute 12 



(2) 



Low-pressure ratio 



i 7 1 2 
.6 



12 expansions by volume. 



High-pressure cut-off 

High-Pressure Cut-Off and Coal or Steam Consumption.* — The 
consumption (either coal or steam), and therefore the horse power 
* Int. Marine Engineering, New York. 

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406 MACHINERY 

developed, vary as the cube of the speed of a steamer at moderate 
speeds. As the high-pressure valve cut-off is the approximate rate 
of steam consumption and therefore of the coal consumption, then 
the variation in cut-off for a given speed may be approximated as 
follows : 

Example. The speed of a steamer is 12 knots, with the high-pressure cylinder 
cut-off . 6. Find the high-pressure cut-off required to reduce the speed to 11 knots. 
12' : 11' = .6 : x (the new cut-off) 
1728 : 1331 = .6 : x 

x = .46 the new cut-off 

Indicator Cards* are important not only for calculating the 
indicated horse power (i. h. p.) but also for giving information on 
the work done in a cylinder. An ideal card is shown in Fig. 69. 

RS is the line of zero pressure (called the absolute pressure line), 
from which all pressures are measured upward according to the 
scale of the diagram. A is the beginning of the downstroke, B 
the point of cut-off, C the point of exhaust, and D the end of the 
stroke. The line AB is the steam line and shows the steam pres- 
sure on the upper side of the piston from the beginning of the stroke 
to the point of cut-off. The line BC is the expansion line and 
shows the decreasing values of the pressure during that part of the 
stroke. At C the exhaust opens and the pressure drops suddenly 
as shown by CD. 

For the return or upstroke, D is the beginning, E the point of 
exhaust closure or beginning of compression above the piston, and 
F the point of steam opening just before the beginning of the next 
downstroke. 

CD is the exhaust line and shows the nearly constant pressure 
during the exhaust period. EF, the compression line, shows the 
increasing pressure on the return stroke after the closing of the ex- 
haust valve. FA, the admission line, shows the sharp jump upward 
as the steam valve is opened, just before the beginning of the next 
downstroke. 

The line PQ is drawn when the space below the indicator piston 
is shut off from the engine cylinder and connected to the air; it 
is the atmospheric line. The distance between RS and PQ repre- 
sents the pressure of the atmosphere, viz., 14.7 lb. per square inch. 
Thus for the downstroke the varying pressures on the top of the 
piston are shown by the varying distances from RS to ABCD, 
* From Practical Marine Engineering. 

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DIFFERENT CARDS 



407 




/c/ecr/ Care? 





Figure 69. — Indicator Cards. 

while for the upstroke the pressures on the same side of the piston 
are shown by the distance from RS to DEFA. 

Analysis of Different Cards (Figs. 69 -and 70). — (1) Eccentric too 
far from a line at right angles to the crank; i. e., angular advance 
is too large. 

Digitized by LiOOQ LC 



408 MACHINERY 

Results. Cut-off too early, steam lead large, exhaust opening 
and closure early. Whole cycle of events is ahead of time. 

(2) Eccentric too near a line at right angles to the crank; i. e., 
angular advance is too small. 

Results. Cut-off too late, steam lead small or negative, com- 
pression small, steam opening late, exhaust opening and closure 
late. Whole cycle of events behind time. 

(3) Steam lap too large. 

Results. Cut-off early, steam opening late, and lead small or 
even negative, port opening small with a probable wire drawing 
of the steam and drop of pressure on the steam line. 

(4) Steam lap too small. 

Results. Cut-off late, steam opening early and lead large and 
port opening" large. 

(5) Exhaust lap too large. 

Results. Exhaust closure early and compression large, exhaust 
opening late and exhaust lead small. 

(6) Exhaust lap too small. 

Results. Exhaust closure late and compression small, exhaust 
opening early. 

(7) Excessive compression. The pressure in the cylinder may 
be carried above that in the valve chest before the steam valve 
opens, thus forming a loop as in Fig. 1. This may be due to either 
(1) or (5)'. 

(8) Excessive expansion (Fig. 7). 

Results. The pressure in the cylinder may fall below that in 
the next receiver or exhaust space beyond, thus forming a loop 
as in Fig. 7. 

(9) Valve stem too long (Fig. 8). 

Results. The nrddle of the stroke of the valve is placed too 
high relative to the ports. The results for an outside valve will 
be to give too much steam lap on top and exhaust lap on the bot- 
tom and too little steam lap on the bottom and exhaust lap on top. 
Hence: steam opening in the top is late and small and the cut-off 
early; steam opening on bottom is early and full and the cut-off late; 
exhaust opening in the top is early and full and the closure late; 
exhaust opening on bottom is late and small and the closure early. 

(10) Valve stem too short. 

Results. Similar to those in (9) but oppositely related to the 
ends of the cylinder. 

(11) Leaky piston or piston rod stuffing box. 

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INDICATOR CARDS 



409 







Figure 70. — Indicator Cards. 



oogle 



410 MACHINERY 

Results. Expansion line will be steeper than it should be. Com- 
pression line may also flatten off somewhat near the top. 

(12) Port openings or passages too small. 

Results. Wire drawing or loss of pressure on the steam line and 
rise of pressure on the exhaust line. 

To Calculate the Mean Effective Pressure and the Indicated 
Horse Power. — Divide the curve obtained from an indicator into 
say 11 even parts and measure the ordinates. Take the mean length 
of all the ordinates, which will be in inches and a decimal, and 
multiply it by the scale of the spring used in the indicator; the 
result will be the mean effective pressure or P in the formula for 
indicated horse power. , . 

Let L = length of stroke in feet 

A = area of piston in square inches 
N = number of single strokes per minute or two times the 
number of revolutions 

P XLXA XN 



Then indicated horse power (i. h. p.) 



33,000 



In estimating the mean effective pressure for any multiple ex- 
pansion engine, it is customary to calculate the pressure that would 
be required if the work were all done in the low-pressure cylinder. 
This is called the mean effective pressure referred to the low pres- 
sure cylinder, and the calculation for horse power then becomes 
identical with the calculation for a single-cylinder engine. For 
a compound engine the referred mean effective pressure is 
M. E. P.. (referred) = low-pressure M. E. P. + 
high-pressure M . E. P. 
ratio low pressure to high pressure 
and for a triple expansion engine 

M. E. P. (referred) = low-pressure M. E. P. + 

intermediate pressure M . E. P. 

ratio low pressure to intermediate pressure 

high-pressure M. E. P. 

ratio low pressure to high pressure 

Below is a table showing the arrangement for calculating the 
i. h. p. The particular engines were installed in a twin-screw car 
ferry. Each engine had cylinders 19, 31, and 53 ins. in diameter 
by 36 stroke, piston valves on the high and intermediate cylinders 



nvJ^v^ 



ENGINE FORMULAE 



411 



with a double-ported slide valve on the low, Stephenson link motion 
air pumps attached to the intermediate crossheads, r. p. m. 92, and 
runs jet-condensing. 









Area 

& 


L'Rth 

Ins. 


Spring 


M. 
E.P. 


Area 

of 

Piston 


IJi.p. 


Lh.p. 


Lh.p. 
Total 


r 


H.P. 


Top 


3.35 


4.13 


80 


64.8 


283.5 


153.8 






Starboard 


H.P. 


Bottom 


2.88 


4.13 


80 


55.8 


267.6* 


125.1 


278.9 




Engine , 


Int. P. 


Top 


2.13 


3.75 


40 


22.7 


754.8 


143.1 








Int. P. 


Bottom 


2.07 


3.75 


40 


22.1 


738.9* 


136.5 


279.6 






L.P. 


Top 


3.58 


4.20 


10 


8 52 


2124 


151.1 








L.P. 


Bottom 


3.45 


4.20 


10 


8.24 


2108* 


145.6 


296.7 


855.2 




H.P. 


Top 


3.37 


4.11 


80 


65.5 


283.5 


155.2 








H.P. 


Bottom 


3.03 


4.11 


80 


59.4 


267.6* 


132.8 


288.0 




Port Engine.- 


Int.P. 


Top 


2.20 


3.78 


40 


23.3 


754.8 


147.0 






Int.P. 


Bottom 


2.18 


3.78 


40 


23.1 


738.9* 


142.8 


289.8 






L.P. 


Top 


3.47 


4.12 


10 


8.44 


2124 


150.0 








L.P. 


Bottom 


3.40 


4.12 


10 


8.26 


2108* 


145.7 


295.7 


873.5 


Total 


1728.7 

























* Assuming piston rod = 4^ inches diameter and no tail rods. 

To Calculate the Coal Consumption per I. H. P. per Hour. — The 
data necessary are: indicator cards from the engine, revolutions 
per minute, and coal consumed during the run. From the indicator 
cards the mean effective pressure may be determined and the 
i. h. p. for one end of the cylinder can be calculated from the formula 

PLAN 

QQ n^ (where N is one half the number of revolutions), and of 

the other end in the same way. The sum of the two gives the total 
horse power for the cylinder. Knowing the pounds of coal con- 
sumed per hour, this quantity divided into the total i. h. p. per hour 
gives the pounds consumed per i. h. p per hour. See also Fuels. 



Engine Formula 

Estimated Horse Power. 

• D = diameter of low-pressure cylinder in inches 

S = stroke of piston in inches 

P = absolute boiler pressure 

R = revolutions per minute 

Z = coefficient for warships 85,000 

short passage express steamers. . . . 91,000 

long passage express steamers 94,500 

passenger cargo steamers 97,000 

cargo steamers 105,000 

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412 MACHINERY 



Estimated Horse Power - D * X ^ X - X R . This formula 

gives a very close approximation to the horse power actually 
indicated when at full speed. 

From A Manual of Marine Engineering, A. E. Seaton. 

Shafting. — A hollow shaft is stronger than a solid one of the 
same sectional area. A shaft will stand twice as much torsional 
stress as bending stress, the constant for torsion being 5.1 and for 
bending 10.2. 

Lloyd's Rules state: Diameter of crankshaft and of thrust 

21 
shaft under collars to be at least ^ of that of the intermediate 

shaft (see table below); thrust shaft may be tapered down at each 
end to same diameter as intermediate shaft. Diameter of screw 
(tail) shaft to be equal to diameter of intermediate shaft X 

.63 -f -~7p-) Dut m no case to.be less than 1.07 T, where P is 

diameter of propeller shaft and T diameter of intermediate shaft 
1 both in ins. 

Let A = diameter of high-pressure cylinder in inches 

B = diameter first intermediate-pressure cylinder in inches 
C «■ diameter second intermediate-pressure cylinder in 

inches 
D — diameter low-pressure cylinder in inches 
S — stroke of pistons 
P — boiler pressure above atmosphere in pounds per square 

inch 



Diameter op Intermediate Shafts 



Type of Engine 



Diameter of Intermediate Shaft in Inches 



Compound, 2 cranks at right angles . . 

Triple, 3 cranks at equal angles . . 

Quadruple, 2 cranks at right angles . . 

Quadruple, 3 cranks 

Quadruple, 4 cranks 



(.MA + .006D+ .025) Xy^T 
(.038 A + .009 £+ .002Z) + .01655) XJfiT 
(.034i4+.011fi+.004C+0.0l4Z)+.0l6S) X^/J 
(.028i4+.OUB+.006C+.0017i)+.015S) Xtyf 
(.0334+.01B+.004C + .00132) +.01555) X^/p~ 



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CYLINDERS 413 

The number of collars on a thrust shaft is roughly one collar up 
to 5 ins. diameter of shaft, and an extra collar for every 1.8 ins. dia. 

or number of collars = 1 H ' \ Q f° r merchant vessels 

1 . o 

. , dia. shaft — 5 . . 

= 1 H rr^ for war vessels 

l.zo 

To find the diameter of the collar, 

D = dia. of collar 

d = dia. of shaft 

N = number of collars 

P = allowable pressure in lb. per sq. in. 
See Thrust Bearing. 
Total thrust (T) = total area X allowable pressure 

Y X N(D* — d*)XP 



Then 



D = 4/ t +d* 



Thickness of collars = .4 (D-d) 
Cylinders.— For ratio of diameters see page 294. If the cylinders 
are to be steam jacketed then liners are necessary. For a cylinder 
without a liner the following formula may be used. 
t = thickness of walls in ins. 
P = max. pressure in cylinder 
D = dia. of cylinder 

(P + 25) D 40 

6000 "*" 100 + D 

When a liner is used the inner surface of the cylinder barrel C 
will have a diameter equal approximately to D -f- 2L -f 2J, where 
D == dia. of the cylinder, L = thickness of the hner, and / = width 
of jacket space, which is usually % or 1 in. 

Connecting Rod. — Length 4J^ to 5 times the length of the crank. 
Diameter at upper end same as diameter of the piston rod, area of 
section at lower end 1.2 to 1.3 that of the piston rod. 
D = dia. at middle of rod in ins. 

L = length from center to cent er in ins. 

K for merchant vessels = .028\/e ffcctive load on piston in lb. 
K for war ves sels =* .022veffective load on piston in lb. 

Then D =*^ L * K 
4 

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414 



MACHINERY 



Piston Rod— 

p = greatest pressure on piston in lb. 

F = a coefficient — naval engines 50 

merchant ordinary stroke 45 

merchant long. stroke 42 

merchant very long stroke 41 

Dia.ofrod = Diaof ; ylinder Xx/p 
Another formula for the piston rod diameter is: 



gj / !• H. P. of one cylinder 
V 2 X length of stroke X 



length of stroke X rev. per mm. 

Pistons. — Often of cast steel dished or conical in form and of a 
single thickness of metal. The pistons of compound and triple 
expansion engines should as a rule have the same total depth, thus 
giving a steep angle to the high pressure and a flat to the low, the 
latter being not less than about 1 : 5. 

Bearing Surfaces. — Allowable pressure in lbs. per sq. in. of pro- 
jected surface using mean loads. 

Crank pin 

Main bearings 

Using Maximum Loads: 
Slipper guides .... 

Crosshead pins 

Link block pin 

Link block gibs . . . 
Eccentric rod pins. 
Drag rod pins .... 

Eccentrics 

Thrust collars .... 



rchant vessels 


Naval 


200- 250 


250- 300 


200-350 


250- 500 


x>ads. 
60- 80 


70- 100 


850-1200 


1200-1800 


750-1000 


850-1200 


250- 400 


350- 500 


700- 950 


900-1100 


500- 700 


700- 800 


150- 200 


175- 225 


50- 80 


80- 100 



[Several of above formulae from Marine Engine Design, by Bragg.] 

Engine Fittings and Accessories 
The Throttle Valve is for controlling the steam to the engine and 
is attached to or placed close to the high-pressure cylinder. For 
ease in quick operating some form of a balanced or power valve is 
necessary. 

Of the balanced type may be mentioned the double-beat, poppet, 
the butterfly, and the balanced piston. The former has two disks, 
the upper being slightly larger than the lower. The chief difficulty 
is to keep the disks tight, as the variations in temperatures tend 



JvJ^Vl^ 



BUTTERFLY VALVES 



415 



to seat the disks unequally. . Butterfly valves have an elliptical 
disk with a spindle in the center. This type is well balanced but 
is difficult to keep tight. Throttle valves with balance pistons 
have such pistons attached to the valve stem, the piston working 
in a cylinder in which steam is admitted, although the valve itself 
is operated by hand. 




Figure 71.— Throttle Valve. [Schutte & Koerting, Phila.] 

Of the power type, this consists of a separate power unit oper- 
ated by steam and connected by links to the throttle valve which 
is controlled entirely by the power unit. 

Cylinder Drains and Relief Valves. — As water collects in the 
steam chests and cylinders, drains and relief valves are fitted. 
The former are placed as low as possible, and are connected to a 
common pipe leading to the bilge* or to the feedtank. Relief 
valves serve as safety valves, relieving the cylinders from exces- 
sive pressure by automatically opening and allowing the water to 
be discharged. 

Starting or Pass-Over Valves. — To assist in starting the engine, 
particularly if the high-pressure crank is on or near the dead center, 

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416 



MACHINERY 



a valve and pipe are provided for admitting steam direct from the 
steam pipe or high-pressure valve chest to the first receiver or 
intermediate valve chest. This will give sufficient load on the pis- 
ton of the intermediate cylinder to start the engine. Either cocks 
or small slide valves are used, that can be opened wide by a single 
stroke of the lever. 

Reversing Engine. — May be direct acting or the all around type, 
usually the former. Diameter of reversing cylinder .185 to .2 the 
diameter of the low pressure cylinder of the main engine. The 
direct acting consists of a steam cylinder mounted on one of the 
engine columns, that is, connected by rods to the links of the 
Stephenson valve gear. The operating lever is located close to the 
one on the throttle valve. Below is a table of sizes of reversing 
and turning engines: 



Engine 


I.h.p. 


17 X 27 X 44 


1,000 
4,000 
4,100 
4,800 


30 
2SH X 39M X 63 


45 
29 X 49 X 84 


54 
29^X47^X2-58 


42 



Reversing Engine 



Turning Gear 



9 ins. dia. X 16 ins. stroke 
12 ins. dia. X 24 ins. stroke 
14 ins. dia. X 24 ins. stroke 
12 ins. dia. X 18 ins. stroke 



Worm and wheel 
Worm and wheel 



Eng. 5 in. dia. X 6 in. 
stroke 

Twin-cylinder engine 
each 4% ins. dia. X 5 
ins. stroke 



Turning Gear. — When steam is shut off, it may be necessary to 
turn the engine. This is done by means of a large wheel, keyed 
to the shaft or shaft coupling, that is driven by a worm gear, which 
may be turned by hand or, as in the case of large engines, by a 
small high-speed engine. See table above. 

Steam Separators. — These are designed to remove water from 
the steam, and to prevent it from entering the high-pressure cylinder. 
This may be accomplished* by having the steam enter a casting 
larger in diameter than the steam pipe, and causing it to make a 
sharp turn around a baffle plate; or giving the steam a whirling 
motion by having it come in contact with spiral plates riveted to 
a cylinder. In the latter case, the particles of water are thrown 
out by centrifugal force, falling to the bottom of the separator, 
and are drained off to a trap. 

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J. LUBRICATING SYSTEM 417 

Lubricating System. 41 — Only the best oil, which has been filtered, 
should be used. See Lubricating Oil. In many engines there is 
a forced feed system, with a pump that is driven by the main engine, 
small copper pipes leading to the guide faces, crank, and piston 
ends of the connecting rods, and to the eccentrics. The main 
bearings should be oiled so there is a film of oil between the shaft 
and the Babbitt metal. 

No internal lubrication of the cylinders is necessary other than 
the swabbing of the rods and the wiping out of the cylinders and 
vaselining them when they are opened. The addition of a small 
quantity of graphite from time to time as the cylinders give indi- 
cations of becoming dry is advisable, but when they have once 
obtained a good surface there is no need of further lubrication. 

Usually crank pins and eccentric straps should be oiled by hand 
once every 20 minutes; main bearings, link gear, etc., once every 
half hour. An inspection of the thrust bearing, spring bearings, 
and stern tube gland should be made every half hour, and the piston 
rods swabbed perhaps every 45 minutes. 

For a triple expansion engine with cylinders 18, 29 and 47 ins. 
diameter by 30 stroke, of 1,000 i. h. p., the following lubricating 
equipment was specified: "A brass manifold shall be located on 
each cylinder provided with wicks and brass tubes leading to prin- 
cipal journals. Crank pins to be oiled by cups and tubes carried on 
connecting rods and taking oil from drip overhead. Cross head 
guides oiled by tubes leading from manifolds. Each eccentric strap . 
to be oiled by cup and tube carried on the eccentric rod. Reverse 
shaft bearings to be fitted with compression grease cups. A swab 
cup shall be fitted to each housing for swabbing the piston rods 
and valve stems. All fixed bearings shall have drip cups. All 
moving parts shall have drip cups made of sheet brass, cast brass, 
or copper with brazed seams. 

Water Service. — The water is often supplied from the circulating 
pump inlet and is pumped through the main bearing jackets and 
cross head guides. The piping is of brass or copper. A hot bearing 
is not always due to lack of lubrication or to a poor water service, 
but may be caused by the shafting being out of line. 

For a triple expansion engine of the size given under the heading, 
Lubricating System, a water service as outlined below was speci- 
fied. "From the main supply pipe there will be one H-inch branch, 
with double swivel joint for each crank shaft bearing. 

* Abstracts from Care of Naval Machinery. H. C. Dinger. 

Digitized by LiOOQ 1C 



418 MACHINERY 

"Two %-inch pipes to each crank pin, extending across on each 
side perforated on the bottom. 

"One %-inch pipe to each cross head guide. 

"One J^-inch pipe to each pair of eccentrics, with double swivel 
joints. 

"Two %-inch pipes to spring bearings. 

"Each of the above branches shall have a separate valve and 
shall terminate either on a pivoted nozzle or a permanent con- 
nection to the part that is to be cooled, as required. All water 
service pipes shall be of brass. 

"The water service pipe shall be connected so as to be supplied 
with sea water from the inlet chest of the salt water side of the 
condenser and to the sanitary pump. There shall be valves at 
these branches. 

"There shall also be a steam connection for blowing out." 

Thrust Bearing. — Directly aft of the crank shaft is the thrust 

shaft and its bearing, the object of which is to prevent fore and 

aft movement of the shafting due to the thrust of the propeller. 

The thrust is taken care of by collars on the shaft that bear against 

shoes on the thrust bearing that may be of cast iron, cast steel, 

or brass with a bearing surface of white metal. The collars must 

run in a bath of oil which is kept cool by salt water supplied by 

the sanitary pump circulating in the bottom of the bearing. 

217 

The mean normal thrust = i. h. p. X -j-: — i — i i: 

speed in knots per hour 

The surface exposed to the thrust should be such that the pressure 

per square inch does not exceed 80 lb., while for tug boats and 

ocean-going vessels it should be about 50 lb. For the number and 

diameter of the collars see page 413. The following is data on a 

21 H X 30% X 44M X 64 . _. . + , . 10 . ,. 4 
=£ : engme. Diameter thrust 12 in., thrust 

bearing of cast iron with cast iron shoes faced with babbitt and 
fitted for water circulation; thrust pressure was taken by 4 collars 
with unit pressure of 60 lb. per square inch. 

Air Pump. — This may be driven by a lever, one end of which 
is fastened to the upper end of one of the connecting rods of the 
main engine or it may be independent. See Steam Plant Auxiliaries. 

Line Shaft or Spring Bearings. — Their chief function is to sup- 
port the shafting. They are of cast iron with a lower brass or 
bearing piece fitted with white metal. - A bearing cap or cover 
forms the top portion in which are grease cups or other lubricating 



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OPERATING 419 

• 

devices. In long lines of shafting the spring bearings are placed 
on each side of the shaft couplings, being at a sufficient distance 
so that the coupling bolts may be easily removed. 

Engine Room Floors. — Preferably of wrought iron checkered 
plates instead of steel, as the former will not polish so readily by 
wear. These plates are supported by angle iron frames fastened 
to the ship's frames. The most comfortable non-slipping floor 
under the conditions of greasy surface and heavy weather is sheet 
lead. The underlying wood platform should be laid so all joints 
are smooth. The sheet lead is about 8 lb. per square foot or y% in. 
thick, and is fastened down by copper nails. Care must be taken 
not to put heavy weights directly on top of. the lead, but on mats. 



Operating * 

"About an hour before the time set for getting under way, start 
to warm up the engine. The length of time depends on the size 
of the engine, for large engines more than an hour may be required 
and for small less. 

"See that all tools, material, etc., are. clear of the engine. 

"Start circulating pump, making sure that the injection and. 
discharge valves are open. 

"See that all parts of the engine are in place and properly se- 
cured. Disconnect jacking gear. 

"Start main air pumps and open main exhaust valves to con- 
denser if these valves are fitted. 

"Open bulkhead stops. 

"Open drains to main steam line. Drain separator. 

"Open boiler stop valves, just cracking them at first and then 
open them gradually. 

"Get reversing engine ready and turn steam in it. 

"Turn steam on jackets and drain them. Open cylinder drains. 

"The steam being up to the throttle, move links back and forth 
with the reversing engine and crack open the throttle slightly. 
This allows a little steam to pass into the high-pressure cylinder 
and warms it up. Crack open pass-over valves to allow steam to 
enter intermediate-pressure and low-pressure cylinders. 

"Circulate water through thrust bearing and slides. 

"See that feed pumps are in proper condition and try all that 
are to be used. 

* From Care of Naval Machinery. H. C. Dinger. 



420 MACHINERY 

"Make an inspection to see that there is plenty of steam, good 
fires and everything about the engines is ready. 

"Get permission to try engines 15 or 20 minutes before the 
time set to be ready. 

"Try engine both going ahead and astern and see that it re- 
verses easily. Care must be taken not to open the throttle too 
wide, otherwise the engine will develop sufficient power to break 
the mooring lines if tied to a pier. 

"The following causes may prevent the engine from working 
satisfactorily: 

"Water in Cylinders. This will prevent the piston moving its 
full travel. The water must be got rid of by opening the drains, 
and moving the piston back and forth by the reversing gear until 
the water is out. 

"Engine on Center. This can be guarded against by taking care 
when the engine is stopped that the high-pressure crank is near the 
middle of the stroke. 

"Valve Rods Sticking. They may be loosened by applying oil, 
loosening the stuffing box or the valve stem guide. 

"Throttle must not be suddenly opened or closed but the engine 
should be worked up to full power gradually. 

"Reversing. The throttle should first be closed and engine 
then reversed — under ordinary conditions. However, if the emer- 
gency signal is received, the engine should be immediately reversed. 

"When under way a great deal concerning the proper running 
of an engine can be told by the sounds heard in the engine room, 
as they tend to combine into a sort of rhythm, and from it the 
experienced engineer can readily tell whether the different apparatus 
is working properly. 

"The chief sound is the heavy thump caused by the pounding 
of the main bearings. This can be located by noting which crank 
has just passed the center when the thump is heard. The main 
bearing will have a duller sound than the crank pin or cross head. 
The cross head knock is a sharper sound and is. not heard at so 
great a distance. 

"Often lost motion ran be told by feeling of the bearings. 

"A valve loose on its stem or piston loose on its rod causes a 
solid, sharp thump or a dull click. 

"On starting up or slowing down, slide valves are apt to rattle 
or cause a clicking sound due to lack of pressure on their backs. 

Digitized by VJiOOQIC 



TRIALS 421 

"Pounding may be caused by: (1) Too much clearance in a 
journal, slide or connection. 

"(2) The use of too light oil on heavy pressure. 

" (3) Power not equally distributed among the cylinders. 

" (1) Can be remedied by readjusting and in part by slowing down 
or changing the speed. 

" (2) Use heavier oil. 

"(3) Readjust the cut-off." 

Trials 

Noronic, passenger steamer, 362 ft. between perpendiculars, beam 

molded 52 ft., depth m61ded'28 ft. 9 ins., engine 29 ^ X47 4 ^ X2 ~~ 58 , 

4 boilers each 15 ft. 6 ins. diameter by 11 ft. long. 

Displacement 5,412 tons 

Area, immersed midship section 776 . 5 sq. ft 

Wetted surface 21,800. sq. ft. 

Draft, forward 11 ft. 3 ins. 

Draft, aft 18 ft. 1 in. 

Draft, mean 14 ft. 8 ins. 

Speed, miles per hour, average 17 . 43 

Slip of propeller 11.6% 

Steam pressure 192 . lb. 

First receiver pressure 73 . lb. 

Second receiver pressure 15 . 5 lb. 

Vacuum 23 . 93 ins. 

Revs, per min 106. 

Indicated horse power, high-pressure cylinder 1,169.6 

Indicated horse power, intermediate-pressure cyl- 
inder 1,505.7 

Indicated horse power, low-pressure cylinder aft . . . 711 .5 
Indicated horse power, low-pressure cylinder for- 
ward. 771.2 

Total indicated horse power 4,158. 

Mean effective pressure referred to low-pressure 

cylinder 34.2 lb. 

I. h. p. per sq. ft. of grate. 13.5 

Sq. ft. of heating surface per i. h. p 3. 16 

Temperature of injection water 40° 

Temperature of hotwell 110° 

Temperature of feed from heater 200° 

Draft ins. of water at fans . . . 3 . 73 

Trial lasted 6 hours. 

Noronic owned by Northern Nav. Co., Sarnia, Ont. Built 1914. 

Huron, freight steamer, 439 ft. 3 ins. length over all, on keel 416 ft., 

15 ^^r^ 



422 MACHINERY 

k KAt* iaaa iuon^ • 19^X28^X41X60 . 
beam 56 ft., molded depth 30 ft., engine -£- > ^ wo 

Scotch boilers each 14 ft. 9 ins. diameter by 12 ft. long. 

Trial draft 18 ft. 6 ins. for'd and 19 ft. 6 ins. aft, and was loaded 
with 4,660 tons. 

Boiler pressure 208 . lb. 

First intermediate receiver pressure 86. lb. 

Second intermediate receiver pressure 37 . 5 lb. 

Low pressure receiver pressure 9.1 lb. 

Vacuum 21.2 ins. 

R. p. m 84.9 

Piston speed, ft. per min 594 . 3 

Mean effective pressure, high-pressure cylinder 81.7 

Mean effective pressure, first intermediate cylinder. 36. 
Mean effective pressure, second intermediate cyl- 
inder 14.97 

Mean effective pressure, low-pressure cylinder 10.38 

Mean effective pressure, referred to low-pressure 

cylinder 34 . 

Indicated horse power, high-pressure cylinder 440. 

Indicated horse power, first intermediate cylinder. . 406. 

Indicated horse power, second intermediate cylinder 356 . 

Indicated horse power, low-pressure cylinder 529. 

Total indicated horse power 1,731 . 

Ratio i. h. p. to grate area 16. 

Ratio heating surface to i. h. p 2.9 

Temperature of injection water 56° 

Temperature of stack 425° 

Temperature of hot well 129° 

Temperature of feed water 178° 

Draft at fan, ins. of water 1 .57 

Coal consumption per hour ..!...* 2,652. lb. 

Coal consumption per i. h. p. per hour 1 .51 lb. 

Speed in miles per hour 11 . 89 

Trial 8 hrs. 17 mins. . " 

Huron owned by Wyandotte Trans. Co., Wyandotte, Mich. 
Built 1914. 

U. S. Torpedo Boat Destroyer Cushing y 300 ft. between perpen- 
diculars, 31 ft. 1 in. beam, 17 ft. 1 in. molded depth, twin-screw 
Curtis turbines, 4 oil-burning Yarrow boilers, closed fireroom, 
forced draft. 

Displacement 1,048 tons 

Draft 9 ft. 5 ins. 

Speed 29. 183 knots 

Main turbines developed a total of 15,280 h. p. at 576 r. p. m. 
Evaporation of the boilers was 11.31 lb. per hour per sq. ft. of 

Digitized by VJiOOQ 1C 



CATTLE STEAMER 423 

heating surface, 15.61 lb. per hour per shaft horse power and 12.46 
lb. per hour per pound of oil. 

Oil consumption 1.259 lb. per s. h. p. 

Trial, 4 hours. Built 1915. 

Cattle steamer, 435 ft. between perpendiculars, 46 ft. beam, 
depth to main deck 37 ft. 11 ins., draft 27 ft. 10 ins., displacement 
11,000 tons, wetted surface 36,050 sq. ft., draft to 27 ft. 10 ins., 

block coefficient .69, engine — 77^ 

1. h. p 2,600 

R. p. m 53.7 

Steam pressure 183 lb. 

Steam first receiver 67 . 5 lb. 

Vacuum 24 ins. 

Speed 11.4 knots 

I. h. p. per 100 sq. ft. wetted surface at 10 knots. . . 4.87 

Coal burned per hour 4,390 lb. 

Coal per i. h. p. main engine per hour . . . . 1 .68 lb. 

Coal per sq. ft. grate per hour 17 . 1 lb. 

The above data is the average of a 3,000 mile run. 

Bristol } cargo steamer, 9,630 tons displacement, mean draft 24 ft. 

. 23^ X 38^ X 67 
9 ins., engme jr 

I. h. p 1,795 

R. p. m 75 

Speed 10.78 knots 

Vacuum * 27 ins. 

Air pressure at fan 1.3 ins. 

Average boiler pressure 162 . 5 lb. 

Temperature of gases base of stack 496° 

Trial 54 hours. 1916. 

Pacific, cargo steamer, for dimensions see table of Turbine 
Steamers. The trial lasted three hours at sea, with a full cargo of 
8,300 tons aboard. 

Draft 25 ft. 

Speed •. 11.5 knots 

Horse power 2,655. 

R. p. m 87. 

Steam at turbine 207 lbs. 

Temperature superheated steam (F.) 420° 

Temperature saturated steam 385° 

Temperature feed water 180° 

Temperature in stack 672° 

Vacuum . . 28 ins. 

Pounds of oil per horse power hour ; . 875 

B. t. u. per horse power hour 16,420. 

Digitized by VjiOOQIC 



424 MACHINERY 

City of St. Louis j passenger and freight, 397 ft. between per- 
pendiculars, 49 ft. 6 ins. beam, gross tonnage, 6,200, engine 
26 X43 X72 4 gcotch y^fe^ g^am allowed 180 lb. At 61.8 

r. p. m., steam 130 lb., engine developed 1,219 i. h. p. 

Lb. of steam per hour 15,276 

Lb. of steam per rev 4 . 12 

Lb. of steam per i. h. p. (1,219) 12.5 

Propeller thrust 16.82 tons 

At 80 r. p. m., steam 155 lb., engine developed 2,843 i. h. p. 

Lb. of steam per hour 30,816 

Lb. of steam per rev 6 . 42 

Lb. of steam per i. h. p. (2,843) 10.8 

Propeller thrust 35. 55 tons 

At a boiler pressure of 152 lb., the intermediate receiver pressure 
was 23 lb. gauge, and low pressure 1.5 lb., vacuum 28 ins., barometer 
reading 29.7 ins., revs, of engine 67.3, i. h. p. 1,386.51. 

Ocean Steamship Co., New York. 

Steamer built in 1910, above data in 1914, on a trip from Norfolk 
to New York. 

PROPELLERS 

Definitions.* — A propeller is right- or left-handed as it turns 
with or against the hands of a watch when looked at when stand- 
ing aft and the ship is being driven forward. 

The face or driving face of a blade is at the rear. It is the 
face that acts on the water and so receives»the forward thrust. 

The back of a blade is the forward side. 

Leading and following edges of a blade are the forward 'and 
after edges .respectively when going ahead. 

The pitch is the longitudinal distance which a vessel would 
travel at one revolution of the propeller, were the propeller to 
revolve in an unyielding medium, as, for example, in a fixed nut. 

' The diameter is the diameter of the circle swept by the tips of 
the blades. 

Pitch ratio is the pitch divided by the diameter. For ordinary 
reciprocating engines the pitch ratio is from .8 to 1.4, but in nearly 
all turbine installations it is .8 or .9. 

For high speed vessels the blades are elliptical in shape, with the 
greatest breadth *about one third from the tip. For towing the 
blades are very broad at the tips. 

* Abstracts from Practical Marine Engineering. 



Digitized 



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PROJECTED AREA 425 

The developed area or helicoidal area of a blade is the actual 
surface of the driving face. 

Projected area is the area of the projection, on a transverse 
plane, of all the blades. In large ships it is usual to design the 
propellers for a pressure of not over 12 lb. per square inch of pro- 
jected surface. 

Disk area is the area of the circle swept by the tips of the blades. 

The area of the propeller tip circle divided into the total ex- 
panded blade area is known as the expanded area ratio or disk 
area ratio, and is usually .3 to .4, but in propellers for turbines 
the ratio varies from .4 to .8 owing to the necessity for crowding 
the required blade surface into a small disk area. Below is a 
formula for calculating disk area ratio. 

Let R — revolutions per minute 

D = diameter of propeller in feet 

H — horse power per propeller 

S = speed in knots per hour 

C = coefficient of .30 

The disk area ratio - C + jJLgJ/5^ 

In the table on page 426 the calculated D A R (disk area ratio) was 
calculated with a coefficient of .30, and it will be noted that the 
results obtained are very close to the actual disk area. 

Number of Blades. — Three blades for warships and four for 
merchant. If the dimensions of a three-blade and a four-blade 
wheel are the same, it will take 25 to 30% more power for the same 
number of revolutions to drive the four-blade than the three. Two 
blades are objectionable on account of the excessive vibration 
caused by them. 

Cavitation. — This is the failure of supplying water to a propeller, 
due to excessive blade velocity; in other words the speed of the 
blades exceeds the speed of the water flowing to them, therefore 
the effective thrust falls off in proportion, as cavities form at the 
sides of the blades. 

Slip. — The apparent slip is the difference between the speed 
of 'the propeller and of the vessel. As a propeller works in a yield- 
ing medium the speed of the vessel is less than the speed of the 
screw. 

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426 

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V 



REAL OR TRUE SLIP 427 

Let v ■■ speed of the screw 
V «- speed of the ship 
v — F « slip of the screw 

0— V 

slip of the screw expressed as a fraction of the speed of the 

screw 

v — V 
Then X 100 = percentage of slip 



Example. A propeller having a pitch of 15 ft. and making 100 revolutions per 
minute would advance 1,500 ft. per minute without slip. If the actual speed of 

the ship is 12 knots, she would travel 12 X ' ~ ■ — 1,215 ft. per minute. The ap- 

00 

* 285 

parent slip is therefore 1,500—1,215 = 285 ft. per minute or . __. =■ . 19 or 19%. 

l,oUU 

The real or true slip is somewhat different from the apparent 

slip, in that the passage of the ship through the water causes 

* some of the water astern to follow the ship. This current of water 

is called the wake, and its speed is dependent upon the shape of 

the afterbody of the ship. Since this current is moving in the 

same direction as the ship, the distance that the propeller advances 

through the moving water in a given time will be less than if the 

water were still. The slip through the moving water, or wake, 

is called the real or true slip, and is greater than the apparent slip. 

Suppose that the wake had a speed of 10% of the ship (it ranges 

from 10 to 20%), or 122 ft. per minute. The propeller would then 

advance through the wake at a speed of 1,215 — 122 = 1,093 ft. 

per minute, and the real slip would be 1,500 — 1,093 = 407 ft. per 

407 
minute, or ^-—^ = .27 or 27%. 
l,oUU 

The difference between real and apparent slip may be expressed 
thus: 

1 - S r = (1 - SJ (1 - W) 
Where Sp = real slip 

= apparent slip 



For the case noted above 1 - S r - (1 - .19) (1 - .10) = .81 
X .9 = .729. Therefore S r = .27 or 27%. 

The apparent slip varies from 5 to 30%, the average being about 
10. Owing to the slip a propeller must be run at a higher number 
of revolutions than would otherwise be the case. 

Digitized by LiOOQ LC 



428 MACHINERY 

Example. In a certain ship the revolutions of the engine averaged about 78 a 
minute. The wheel was 14 ft. 6 ins. diameter and 15 ft. pi&h, the speed of the 
steamer being 10 knots. Find the slip of the screw. 

_, x i- • Pitch X r. p. m. — speed in ft. per min. 

The apparent slip is = ... ., 

* * pitch X r. p. m. 

15 - 78 . 134 or about 13H%. 

Formulae for Finding Slip, Speed, Revolutions, and Pitch of 
Propellers.* 
Where p =* pitch of propeller in feet 
N = revolutions per minute 
V = speed in knots of ship 
s = slip ratio (that is, the apparent slip in per cent) 

(1) To find the slip, having given the pitch, revolutions, and speed 
in knots. 

_ p N - 101.3 V 
8 ^N 

(2) To find the speed, having given the pitch, revolutions, and 
slip. • 

v = e N (1 - s) 

101.3 

(3) To find the revolutions, having given the speed, pitch, and 
slip. 

101.3 V 



N - 

To find the pitch 
lutions. 



V (1 - s) 
(4) To find the pitch, having given the speed, slip, and revo- 

101.3 V 



N (1-s) 



Approximate Rule for Finding the Pitch of a Propeller. — The 

pitch of a propeller will equal the length of a circumference at the 
place where the slope of the face is 45°, or where it is equally in- 
clined to the shaft and to the transverse direction. Starting near 
the shaft, the inclination to the longitudinal is small, but increases 
toward the tip, passing at some point through the value of 45°. 
At this point let the radius be r. Then the pitch of the propeller 
is equal to 2 X 3.1416 X r very nearly. 
* From Practical Marine Engineering. 

Digitized by LjOOQ IC 



TURBINE SHIPS m 

To Find the Helicoidal and Projected Area of a Propeller in Place. 

— Stretch a large piece of ordinary brown manila paper smoothly 
over the driving face of one blade and press it down around the 
edges to get the contour. Trim the paper to the crease and calcu- 
late the area either by the trapezoidal or by Simpson's rule. If 
by the former and one breadth is located at the extreme tip, the 
area is the sum of half the tip and hub breadths plus all the others, 
multiplied by the distance radially between successive 'breadths. 
The projected area may be determined from the developed area 
with a reasonable amount of accuracy by either of two formulae, the 
first proposed by S. Barnaby and the second by D. W. Taylor, chief 
constructor, U. S. N. 



/-, \ t*_ • x' j Developed area 

(1) Projected area = — - 

4/1+ .0425 Pitch 



Diameter 



(2) Projected area = Developed area 1 1.067 — yr: - — 1 

The first is not accurate for pitch ratios (pitch divided by diam- 
eter), varying much from 1. The second holds over a range of pitch 
ratios from .6 to 2, which is all that is customarily met with. 

To Find the Thrust of a Propeller upon the collars of a thrust 
shaft, use the formula: 

m A , ., A . , h. p. of engine Xpropeller efficiency X33000 

Total thrust in pounds = — - -f-= — - . . £ ~ 

speed of vessel in feet per mmute 

See also Thrust Bearing. 

Example. A 120 h. p., internal combustion engine running at 450 r. p. m. drives 
a boat at 20 miles an hour. What is the total thrust in pounds upon the thrust 
collars. 

Assume the propeller efficiency is about 60% and substituting in the above 
formula, 

120 X .6 X 33,000 2,376,000 



20 X 5,280 1,760 

60 



1,350 lb. which is the total thrust. 



Wheels for Turbine Ships. 

R =s revolutions of the screw per minute 
V = speed of the vessel in knots per hour 
S. h. p. = shaft horse power developed in the shaft and deliv- 
ered to the screw 

Digitized by LiOOQ IC 



430 



MACHINERY 



E. T. P. =* effective thrust power = S. h. p. X suitable factor. 
The effective thrust is the power required to propel 
the vessel and is equal to the S. h. p. times a 
coefficient varying from .55 to .52. The effective 
thrust in pounds is given by the formula. 

S. h. p. on one shaft X 33,000 X .52 or .55 
V X 101.3 



Diameter of propeller in feet 



__ \/ effective thrust in pounds 
C 



For value of C see following table. 

Apparent slip of propeller per cent. = .0206 R + 12. 

Pitch. — Suppose it is required to find the pitch of a propeller to 
drive a ship at 23 knots, the turbines making 520 revolutions per 
minute. 

The apparent slip - .0206 X 520 + 12 - 22.712 per cent. 



Speed of screw at 23 knots = 23 + 



22.7 
100 



X 23 - 28.22 knots. 



D .. , 28.22 X 101.3 _. ft ,. K * ft . 

Pitch =* p^r — 5.49 ft., say 5 ft. 6 ins. 

Pressure per square inch of developed surface = .00563 R -f- 7.5 



Type of Vessel 


Speed 

in 
Knots 


Revolu- 
tions of 
Turbines 

per 
Minute 


E.T.P. 


Apparent 
Slip of 
Propeller 
Per cent 


Pressure 
per Sq. In. 
on Devel- 
oped Sur- 
face in 
Pounds 


Ratio of 
Developed 
Surface to 
Disk Area 


C = Coeffi- 
cient 


S.H.P. 


for 
Diameter 


Large ocean mail str . . 
Intermediate mail str . 
Cross channel steamer 
Fine-lined fast vessel. . 


24 to 25 
21 to 23 

24 

28 


190 to 200 

330 
500 to 550 

750 


.53 
.55 
.53 
.52 


16.5 
18.8 
20.5 
27.5 


8.75 
9.35 
10.3 
11.72 


.535 . 
.73 


23 

24.6 
25 
30 



Taper of shaft hole in boss to be not 
shaft dia. 



6 



+ .6. Thickness of 



Taper in Propeller Boss 
less than % in. per foot. 

Propeller Key.— Width of key 

key = width of key X .5. 

Propeller Nut.— Diameter of nut = shaft dia. at screw X 1.5. 
Thickness of nut = shaft dia. at screw X .75. The nut is left 
handed for a right hand propeller, and right for a left hand. 



Digitized 



by Google 



MOTOR BOAT PROPELLERS 



431 



Motor Boat Propellers. — Those in the following table have three 
blades. A two-blade should be about two inches larger in diameter 
to hold the engine to the same number of revolutions as a three- 
blade of the same pitch and style. The table is based on speed 
wheels up to and including 35 ins. in diameter, while above this 
size it is based on a towing wheel having broader tips. 





Revolutions per Minute 


Horse 












Power of 


300 


400 


500 


Engine 














Dia. 


Pitch 


Dia. 


Pitch 


Dia. 


Pitch 




Ins. 


Ins. 


Ins 


Ins. 


Ins. 


Ins. 


2 


18 


20 


14 


19 


12 


18 


3 


18 


26 


16 


20 


14 


17J4 


4 


20 


26 


18 


22^ 


16 


18 


5 


20 


30 


20 


20 


16 


20 


6 


22 


24 


20 


25 


18 


19 


7 


22 


30 


18 


30 


18 


22 


8 


24 


30 


20 


27 


18 


25 


10 


26 


30 


22 


273^ 


18 


28 


12 


28 


28 


24 


26 


20 


25 


14 


28 


30 


26 


30 


22 


24 


16 


30 


30 


28 


28 


24 


24 


18 


30 


33 


28 


30 


24 


26 


20 


30 


36 


30 


30 


24 


28 


22 


30 


39 


30 


31J^ 


24 


30 


25 


30 


42 


30 


33 


26 


28 


28 


32 


37 


30 


35 


26 


30 


30 


32 


38 


30 


37^ 


26 


32 


32 


32 


39 


32 


31 


28 


30 


35 


34 


39 


32 


32 


28 


32 


38 


34 


40 


34 


32 


30 


30 


40 


34 


41 


34 


33 


30 


31 


42 


34 


42 


34 


34 


30 


32 


45 


34 


43 


34 


35 


30 


33 


50 


38 


38 


36 


33 


30 


35 


55 


38 


40 


36 


34 


30 


37 


60 


40 


38 


36 


35 


30 


39 


65 


40 


40 


36 


36 


32 


33 


70 


40 


42 


38 


36 


34 


32 


75 


42 


42 


38 


38 


34 


34 


80 


44 


42 


38 


40 


34 


36 


85 


44 


44 


40 


38 


36 


34 


90 


46 


44 


40 


40 


36 v 


36 


95 


46 


46 


42 


40 


36 


38 


100 


48 


46 


42 


42 


■ 38 


38 



Digitized 



by Google 



r 



432 



MACHINERY 



The areas of all three blades of the 
are as follows: 



speed and towing wheels 



Diameter, Ins. 


Area Speed Wheel in Sq. Ins. 


Area Towing Wheel, Sq. Ins. 


12 


45 




14 


63 




16 


78 




18 


99 




20 


126 




22 


159 


180 


24 


193 


212 


26 


229 


247 


28 


267 


290 


30 


309 


340 


32 


353 


390 


34 


399 


440 


36 


451 


490 


38 




545 


40 




600 


42 




660 


44 




730 


46 




800 


48 




870 



Above data from Columbia Brass Foundry Co., New York. 

For larger wheels see table of Merchant Ships, also the table 
on page 426. 
Blade thickness if continued to shaft center line 



/ 



shaft dia. 8 



X constant 4 -f-.5. Thickness 



number of blades X boss length 

at tip =» constant .04 X propeller dia. in ft. + .4. 

Diameter and length of boss = constant 2.7 X shaft dia. Boss 

diameter varies from V4 to 1 / 6 propeller diameter, curve of boss radius 

is taken with a radius equal to boss dia. X .8. 

[Formula for Taper, Key, Blade thickness, etc., from Verbal Notes. J. W. M- 
Sothern.] 

Weights op Propellers 
Weights of cast iron propellers are given in the table, but if the 
weight of any other material is wanted it can be obtained by the 
formula. 
Weight of new wheel = 

weight of cast iron wheel X weight per cu. ft. of new material 



weight per cu. ft. of cast iron 
The pitch is 1J^ times the diameter. 

Digitized by 



Google 



SPEED TABLE 



433 



Dia., Ins. Two B 


ades, Lb. 


Three Blades, Lb. 


Four Blades, Lb. 


12 


9 


12 


15 


14 


12 


19 


20 


16 


19 


24 


24 


18 


21 


26 


32 


20 


22 


28 


44 


22 


25 


35 


55 


24 


30 


51 


67 


26 


55 


68 


92 


28 


80 


110 


120 


30 : 


100 


132 


124 


32 


. . . 


140 


196 


34 


. . . 


. . . 


220 


36 


. . . 


• . • 


225 


38 


• . • 


• . . 


282 


40 


, . . 


• . • 


330 


42 


• • • 


• . . 


350 


44 


• . . 


• . . 


370 


46 


. . • 


... 


380 


48 


, . . 


... 


510 


50 


, . . 


... 


525 


52 


. . 


. . 


545 


54 


. . 


... 


575 


56 


. . 


. . . 


595 


58 


• «. 


... 


680 


60 


. . 


... 


900 


62 


. . 


... 


925 


64 


• • 


.'. . 


950 


66 


. • 




1,050 


68 


. . 




1,220 


72 






1,380 


76 




. . . 


1,450 


78 




• . . 


1,650 


80 






1,870 


84 




. . . 


2,000 


88 




• . . 


2,150 


92 




• . . 


2,760 


96 




... 


3,150 


120 


. . 


... 


5,600 


144 




. . . 


7,600 


150 




... 


8,450 


Sheriffs Mfg. Co., Milwaukee 


, Wis. 







Speed Table. — This gives the speed in miles per hour of boats 
with propellers of ordinary pitches at common engine speeds, and 
also the percentages of slip and theoretical speed of the propeller. 
Four speeds are given for each pitch at each engine speed, corre- 



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t^'t^co'io aot^cd<e a»odt^«o a»aoi><e> oooon *-«©oio6 co'^©o» 






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435 



Digitized 



by Google 



i 



436 MACHINERY 

sponding to .four percentages of slip. The percentage marked 
"None" indicates no slip and is the theoretical speed of the pro- 
peller. Thus a 20-inch diameter by 30-inch pitch wheel at 500 
revs, per min. shows in the 30-inch pitch column a theoretical speed 
of the boat as 14.2 statute miles per hour. 

To find the percentage of slip for a boat traveling 10 miles per 
hour, engine making 500 revs, per min., the propeller having a pitch 
of 28 ins., follow the column for 28-inch pitch down to the line 
500; 10 miles per hour is not shown by the percentage of slip for 
10.61 miles is 20% and for 9.28 is 30%; therefore the percentage for 
10 miles would be about 25%. 

For a new boat, knowing the revolutions of the engine and the 
desired speed in miles per hour, to find the pitch of the propeller, 
first estimate the percentage of slip according to the type of boat 
then for the known r. p. m. and percentage follow the line to the 
right to the figure nearest the desired speed. Follow the column up 
and the pitch will be found at the top. 

PADDLE WHEELS 
In the old type of harbor and bay steamers the wheels consisted 
of iron frames with boards fastened transversely to them. The 
present practice is to have feathering paddles, the bottom of the 
floats being about one-third of the draft. The breadth of each 
paddle in side wheelers is about one-third the breadth of the steamer, 
while in stern wheelers the paddles are nearly the entire breadth. 
. Formulae for Finding Slip, Speed, Revolutions, and Pitch of 
Paddle Wheels.* 

Where x - 3.1416 

8 = slip ratio 

V = speed in statute miles per hour 

N — revolutions per minute 

D =■ diameter of pitch circle 

For the same properties as given under the section on Propellers. 

/tx DN-88V 

(1) * ~ *DN 

(2) y m >Dy«) 

(3) N mV 



x D (1 - «) 
• From Practical Marine Engineering. 



Digiti 



zed by G00gk 



STEAM TURBINES 



437 



(4) D = 



88 V 



T N (1-8) 

Immersion of floats should not be less than }/& their breadth and 
for general service should be l A. 

Number of floats .varies with the diameter. With fixed radial 
floats the usual proportion is one for each foot of diameter, and ii 



feathering, number of floats 



Diameter -}- 2 



60 



/area 
Breadth of float = A / ~T~ 

-r y^ 



V revolutions 



Length of float 



a rea 
r 



In practice, r, the ratio of length to breadth, is 4 to 5 with fixed 
radial wheels and 2.6 to 3.0 with feathering. 

Paddle Wheels 









Diameter 








Speed, 
Knots 


Indicated 


Area of 


to Centers 


Revolu- 






Horse 


Paddle, 


of 


tions per 


Slip . 


Name 


Power 


Sq. Ft. 


Paddles, 


Minute 












Feet 








13. 


717 


12.55 


23.9 


21.8 


.197 


Nantucket 


13. 


902 


19.56 


18.9 


29.0 


.234 


Uncatena 


13.5 


966 


27.48 


18.5 


26.4 


.141 


Gay Head 


18.3 


2520 


34.00 


16.4 


41.0 


.155 




18.3 


2680 


34.10 


17.0 


47.0 


.265 




18.8 


3400 


45.20 


18.7 


40.0 


.170 


Tashmoo 


18.9 


6472 


48.00 


24.5 


33.3 


.250 


City of Erie 



STEAM TURBINES 

The fundamental difference in the operation of a reciprocating 
steam engine and a steam turbine is that in the former the steam 
does work by its pressure overcoming resistance, and in the latter 
the steam does work by its kinetic energy. 

In turbines the velocity of the jet or jets is utilized to produce 
rotation of vanes. Velocity is produced in a steam jet only by 
expanding from one pressure to a lower one, so that regardless of 
the type of turbine there must always be a pressure drop to gen- 
Digitized by vjiOOQIC 



438 



MACHINERY 



erate the velocity which is utilized. The velocity imparted to 
the jet may be utilized in two ways: (1) by impinging on a vane 
and driving the vane by impulse; or (2) by driving backwards the 
nozzle in which expansion has taken place owing to the reaction or 
kick-back of the steam in coming to a high velocity from a low one 
by expanding through the pressure drop. No. 1 is basic for impulse 
turbines and No. 2 for reaction turbines. If a large pressure drop 
is available, this means a high nozzle velocity, and in some cases 
it is difficult to utilize efficiently a high velocity, so recourse is had 
to making the pressure drop occur a small amount at a time, each 
drop in pressure and attendant increase in velocity being but a 
fraction of the over-all drop; this is known as pressure compounding. 
The same result may be obtained by arranging several rows of 
vanes so that each row takes out a certain fraction of the velocity 
of the jet, as, for example, if a pressure drop of 150 lb. gives a 



nozzle 




SHggfflL— 



MOVING VANES 

<~Si mple Impulse (DcLaval) 




NOZZLE 



<««««« 



MOVING 

VANE S 




««««««* 



NOZZLES 



MOVING 
VANES 




<<<<<<<<<«« 



MOVING 
VANES 



•Pressure Compounding (Rateau, Zoclly and Hamilton* 
Holzwarth) 
Figure 72. — Arrangement of Vanea. 

Digitized by LiOOQ 1C 



PARSONS TYPE 439 

nozzle velocity of 3,600 ft. per second, the peripheral velocity of 
one row of vanes, to utilize all of it, would be 1,700 ft. per second, 
but if there were four wheels, the velocity of each would be but 
one-fourth of this, or 425 ft. per second. This is called velocity 
compounding. (See Fig. 73.) Frequently both pressure and ve- 
locity compounding occur in one turbine, as, for instance, the 
Curtis type, where the turbine as a whole is of the compound pres- 
sure type with each pressure stage of the compound velocity type. 

There are no turbines of the pure reaction type in commercial 
use. The turbine most commonly classed as of the reaction type is 
the Parsons (see Fig. 74) in which there is a small pressure drop 
in the first row of vanes, the reaction from which tends to cause 
the vanes to rotate away from the direction of discharge. In the 
next row the same action takes place, but the vanes being fixed, 
the jet impinges against the following rows of moving vanes which 
feel the compound effect of this impulse and the reaction due to 
the further expansion through the second moving row. This cycle 
is repeated throughout the rest of the turbine. 

The usual number of expansions (this refers to large turbines 
of the Parsons type) is four in the high-pressure turbine, and eight 
in each low-pressure, the total number of rows of blades being the 
same for each separate turbine. Thus if the high-pressure turbine 
is made up of say f our ex pansions, each containing 16 rows of 
blades, then each low-pressure turbine will have eight expansions, 
each containing eight rows of blades. A pair of rows, consisting 
of one row of fixed and one of moving blades, is usually called a stage. 
The sectional areas of the steam passages in Parsons turbines 
increase from the high pressure end to the low, so advantage is 
taken of the expansive properties of the steam. 

(Above paragraphs from Int. Mar. Eng'g, 1916.) 

In a modern triple expansion engine with cylinder areas of say 
high pressure to low pressure as 1 is to 7.5, and with a cut-off in 
the high pressure of one-third the stroke, the total number of steam 
expansions would be 7.5 X 3 = 22.5. In turbines the expansions 
of steam are much more than this, as 125 to 140 expansions are 
readily obtained. With a high-pressure turbine having an initial 
pressure of 150 lb. and a condenser vacuum of 29 ins. or back pres- 
sure of say 1 lb., the steam would expand about 150 times. Thus 
more work can be got out of the steam by the increased number of 
expansions, and hence the importance of having a high vacuum 
in the condensers. 

Digitized by VjiOOQIC 



440 



MACHINERY 




NOZZLt. 



axr<«««<; 



"MOVING 
VANES 



^tttt y y yyy ) n * €D * mt vanc$ 

(SMfflLT 



_ MOVING 
_ VANES 



V Velocity Compounding (A. E. G. (Small), Electra 
and Terry) 

Figure 73. 

Impulse turbines which are directly connected to generators 
for lighting consist of a row of nozzles which are fixed and a single 
row of moving vanes. For marine purposes they are not built 
much larger than 250 Kw. (See section on Electricity.) 

In turbines the velocity of the steam is about 300 ft. per second 
or 18,000 ft. per minute. 

An arrangement often adopted, in steamers of 400 ft. or so in 
length, is to install five turbines, three for ahead and two for re- 
verse running. There are three shafts with one propeller on each, 

Notable Ships Driven by Parsons Turbines 



Name 


Length 
Feet 


Displace- 
ment 

in 
Tons 


Horse 
Power 


Steam Con- 
sumption 

per a. h. p. 

Hour for All 
Purposes 

in Pounds 


Speed 
in Knots 


When 
Built 




100 
250 
360 
490 
785 
901 


44 H 

650 

3,000 

17,900 

40,000 

49,430 


2,300 
3,500 
14,000 
24,712 
74,000 
56,000 


15. 

16. 

13.6 

15.3 

14.4 


32.75 

20.48 

23.63 

21.25 

26. 

24. 


1897 


King Edward * 

ff.M.S. Amethyst 

H.M.S. Dreadnought. 


1901 
1905 
1906 
1907 




1914 







* For further particulars see Turbine Ships. 

the reversing turbines being placed within the low-pressure ahead 
casings. When running ahead the reverse turbines revolve inertly 
in a vacuum of 24 to 26 ins., and when going astern the ahead 

Digitized by vjOOQLC 



ARRANGEMENT OF VANES 



441 



turbines run in a vacuum. The transatlantic liner Maureiania has 
four shafts and six turbines. The extreme outboard shafts are 
driven by the high-pressure turbines, while the inboard are driven 
by the low-pressure, forward of which are the astern turbines. An 
arrangement of five turbines as installed in an English Channel 
steamer is as follows: Speed 22 knotjs, shaft horse power 6,500, 
boiler pressure 160 lb., high-pressure turbine 140 lb., low-pressure 




zzlcs 



TUl«U««JTT 



~ MOVING 
^ VANES. 







«a«««arax* 



r MOVING 
\ VANES. 



7TTymr»m»» 



FIXED fiWOE VAHES. 



NG 



a««««(rc«+ — -gags 

• Pressure Compounding with Velocity Compounding 
(Curtis Marine Type and large A. E. G.) 



JJJJJJMJMZJ™. 



GUIDE VANES. 



XSSSSSHSE!^ 



• MOVING VANES. 



jjjjjss&xa? 



FIXED GUIDE VANES- 



XBS30ag3SHF 



:movihova«e5 



JJMJMJZXB 



F 1*10 GUIDE VAN E3- 



Reaction (Parsons) 
Figure 74. — Arrangement of Vanes. 



-MOVING VANES. 



Digitized 



by Google 



442 MACHINERY 

i 

turbine port 20 lb., low-pressure starboard 20 lb., condenser vacuum 
24}^ ins., low-pressure port astern turbine 23 ins. vacuum, and th.2 
same for the low-pressure starboard astern, revolutions 630 per 
minute, propeller pitch 4 ft. 6 ins., slip 21%. 

Geared Turbines. — In recent practice the driving of the pro- 
peller shaft by the turbine through intermediate gears has been 
tried in both merchant and war vessels. By means of gearing, 
a high-speed turbine occupying a small space can drive a large 
diameter propeller at a slow speed. This arrangement admits of 
economy at low ship speeds owing to the fact that turbines are 
more efficient when running at a high speed and propellers at a low. 
In single-screw vessels both the high-pressure and the low-pressure 
turbines have pinions meshing directly with the gear on the propeller 
shaft. Experience has shown that there is no reason to expect a 
loss of energy of more than 1 J^ to 2% in the gearing and its bearings. 

For cargo steamers of 15 knots or under, geared turbines have 
pioved satisfactory. At higher speeds few have been installed. 
Confining attention to vessels of the cargo carrying class at speeds 
below 15 knots, the margin between the several methods of pro- 
pulsion (see table on page 496) is so small that local or economic 
conditions which have no bearing on engineering features are often 
the deciding factors. Geared turbines undoubtedly operate on 
increased steam economy, but there is little difference in the ma- 
chinery weight and space, and the first cost is higher than recip- 
rocating engines. Below is data on a cargo vessel driven by 
geared turbines. See also table of Turbine Ships. 

Cargo vessel, 275 ft. long, 38 ft. 9 ins. beam, 21 ft. 2 ins. deep, 
draft 19 ft. 8 ins., displacement 4,350 tons. Two boilers 13 ft. 
diameter by 10 ft. 6 ins. long, heating surface 3,430 sq. ft., grate 
surface 98 sq. ft., steam 150 lb., natural draft, condenser cooling 
surface 1,165 sq. ft. 

Two turbines in series, one high pressure and one low, former 
on starboard side and latter on port. High-pressure turbine 3 ft. 
diameter by 13 ft. over all; low-pressure 3 ft. 10 ins. diameter by 
12 ft. 6 ins., the reversing turbine being in the casing for the low. 

Gear wheel (cast iron) on propeller shaft, 8 ft. 3^ ins- diameter 
of pitch circle, 398 teeth double-helical with a circular pitch of 
.7854. Total width of face of wheel 24 ins., inclination of teeth 20° 
to the axis. Pinion shafts of chrome nickel steel, 5 ins. diameter of 
pitch circle with 20 teeth, .7854 circular pitch. Ratio of gear to 
pinion 19.9 to 1. 

Digitized by LiOOQ 1C 



GEARED TURBINES 



443 



Propeller wheel 14 ft. diameter, 16.35 ft. pitch, expanded area 
70 sq. ft. 

Speed by log 10.22 knots 

Revolutions per minute 70 .6 

Boiler pressure 140 lb. 

High-pressure turbine, initial pressure Ill lb. 

Vacuum in inches 28 .4 

Barometer, inches 29 .88 

Water, pounds per hour consumed by turbine. . . . 14,510 . 

Shaft horse power 960 . 

Water consumed in pounds per s. h. p. 15 . 1 

Comparative Performance of Geared Turbines and Recip- 
/ rocatIng Engines* 

Steamer 370 ft. X 51 ft. X 27.8 ft., 9,950 tons displacement, on 
23.4 ft. mean draft, block coefficient .779. Single screw, driven by 
geared turbines. Three boilers, steam 180 lb;, speed 10 knots. 
Name, Cairncross; type, cargo steamer. 

Sister ship, same as above, but with reciprocating engines, 

24X40X66 

j= . Name, Cairngowan. Results of a 36-hour trial follow: 



Geared 
Turbines 



Reciprocating 
Engines 



Mean revs, of screw per minute 

H. p. developed 

Steam 

Temp, of sea water F 

Temp, of discharge from condenser. . . 

Temp, of hot well 

Temp, of feed water 

Vacuum in condenser 

Coal consumed per 24 hours, tons. . . . 
Coal consumed per i. h. p. hour, lb. . . 
Coal consumed per sq. ft. of grate, lb. 

Water consumed per hour, lb 

Water consumed per i. h. p. hour, lb. . 
Ash from coal as measured, per cent. . 



61.76 

1,570 s.h.p. 

138 lb. 

50° 

70°. 

79° 

203° 

28.75 ins. 

27.8 

1.45 

17.9 

22,400 

12.57 

8.50 



61.68 

1,790 i. h. i 

1401b. 

50° 

95° 

104° 

221° 

26.80 ins. 

32.7 

1.704 
21 

27,200 

15.18 

8.97 



See also table of Comparative Performances of Different Systems of Propulsion. 

The Fottinger hydraulic transmitter for turbines consists of a 
high-speed turbo-centrifugal pump with a water turbine designed 
for a low speed. The pump is coupled direct to the steam turbine, 

* From Marine Steam Turbines. J. W. M. So them. 



Digiti 



zed by G00gk 



444 



MACHINERY 



and the water turbine to the propeller shaft, both being in one 
casing so designed that frictional and eddy losses are reduced to 
a minimum. The transmission efficiency of this transformer is 
about 90%, and it has the advantage of being able to employ a 
non-reversible turbine. 

In Alquist gearing, the gear is built up of a number of plates 
machined to a form which gives them the desired degree of lateral 
flexibility. Each disk or plate operates independently and is free 
to deflect laterally under the side pressure which results from its 
diagonal engagement with the pinion. A very small amount of this 
lateral deflection is sufficient to afford the desired distribution of the 
load, and this amount can be given without approaching dangerous 
periodic strains. With gears of the Alquist type very small teeth 
can be used without any danger of incurring excessive strains on 
the individual teeth. Alquist gears are built by the General Electric 
Co., Schenectady, N. Y. Below are tests of two steamers of the 
same size and model, both using oil fuel, one being driven by turbines 
with Alquist gears and the other by reciprocating engines. 



8. 8. La Brea 

Alquist 

Gear 



S. S. Los 

Angeles 

Reciprocating 

Engine 



Average speed, knots 

Total lbs. of oil used in steaming 

Total shaft horse power hours 

Lbs. of oil per shaft horse power hour 
Rev. of propeller per min 



10.9 
8,270,000 
8,029,000 

1.03 
90 



10.27 
7,310,000 
5,538,000 

1.32 
65 



Steamers owned by Union Oil Co., Los Angeles, Cal. 

Turbo-Electric Propulsion. — Here the turbine drives a generator 
which furnishes the current to an electric motor directly connected to 
the propeller shaft. Where a wide range of high efficiency is required 
for a variety of speeds, electric propulsion has proved satisfactory. 
The advantages of this method of propulsion are: the loss due 
to the electrical machinery is more than counterbalanced by the 
gains secured with high-speed turbines and suitable reduced speeds 
of propellers; full effective power is available for going astern; 
the turbines always run in one direction, the reversing being done 
by changing the direction of the current at the motor; an improved 



Digitized 



by Google 



TURBO-ELECTRIC PROPULSION 



445 



economy at low speeds is secured, which in war vessels means an 
increased radius of action. 

In the U. S. collier Jupiter, the generating unit (turbine and 
generator) is similar in design and construction to units on shore, 
the generator being a three-phase, 2,300-volt, 5,000 kw., furnishing 
current to two electric motors one on each shaft, there being two pro- 
peller shafts. The motors are of the three-phase induction type 
and have 36 poles. Each is installed in a well surrounded by a 
coaming, so that it cannot easily be filled by sea water. The wind- 
ings are waterproof and not at all sensitive to moisture. When prompt 
reversal is required it is desirable to cut in the resistance in the motor 
circuit. This is done by levers attached to the motor frames. Rever- 
sal under such conditions is accomplished by first opening the field 
switch which deenergizes the circuit, then moving the levers which 
cut in the resistances, then throwing the reversing switches, and 
lastly reestablishing the field circuit. These operations are simple 
and can be accomplished in a very few seconds. Locking devices 
are provided so that no error can be made. 

The following table gives data on three U. S. colliers, viz., Jupiter, 
Neptune and Cyclops. The former is electrically driven, the Nep- 
tune is driven by geared turbines and the Cyclops by reciprocating 
engines. 





Cyclops 


Jupiter 


Neptune 


Displacement 


20,000 
5,600 
88 r. p. m. 
88 
280 

2 triple ex- 
pansion 
engines 

14 (estimated) 
14.6 knots 


20,000 

2,000 r. p. m. 
110 
156 

1 turbo-gen- 
erator and 
2 motors 

11.2 


20,000 


I. h. p. at 14 knots 


Engine or turbine speed at 14 knots. . . 

Propeller, r. p. m., at 14 knots 

Weight driving machinery in tons 

Character of driving machinery 

Steam consumption in pounds per shaft 
horse power per hour 


1,250 r. p.m. 
135 

2 turbines 
each with 
gearing 


Speed maintained on 48-hour trial 


13.0 knots 



One of the largest electric installations is in the 30,000-ton U. S. 
battleship California. Here the current for propelling the battle- 
ship is generated by two 18,000 h. p. turbo-generator sets running 
at 2,200 r. p. m., furnishing the current to four 7,500 h. p. 
induction motors, giving a speed of 22 knots. At 14 knots only 
7,000 h. p. is required. Due to the high efficiency of the electric 
speed adjustment system employed it is claimed that the steam 



ile 



446 



MACHINERY 



Pounds of Steam per Hour per Effective Horse Power 
For Direct Drive Turbines, Reciprocating Engines, and Turbo- 
Electric Units 



Name 


How Driven 


Speed in Knots 


Revolutions 
of Pro- 


12 


19 


21 


pellers at 
21 Knots 


U. S. Battleship Florida 

U. S. Battleship Utah 

U. S. Battleship Delaware . . . 

U. S. Battleship California. . 


Parsons Turbines 
Parsons Turbines 
Reciprocating 

engines 

Turbo-Electric . . 


lb. 
31.8 
28.7 

22. 
17.3 


lb. 
24. 
20.3 

18.7 
15. 


lb. 
23. 
21. 

21. 

16.4 


32S 
323 

122 
175 



Estimated weight of the propelling machinery of the California without con- 
densing auxiliaries is 530 tons. x The contract price with auxiliaries was $431,000. 

consumption per horse power hour will be approximately the same 
at both speeds. Seventy-five per cent, of the power generated 
theoretically by the ship's turbines will be delivered to the genera- 
tors, and it is estimated that there will be a loss of only 8% in the 
electrical equipment. In addition to the electric power for pro- 
pulsion, all of the engine room auxiliaries will be electrically driven 
by direct current taken from the small, non-condensing turbo- 
generators that supply excitation for the main generators. It is 
said that the use of electric drive on the California represents a 
saving of about $200,000 in the first cost of the propelling machinery, 
and that it offers superior economy in operation, besides reducing 
the weight of the propelling machinery and providing full power 
for reversing without the addition of astern turbines as is the case 
in direct turbine drive. 

Efficiency. — Marine steam turbines have an efficiency of 55 to 
65% when running at their designed speeds. At other speeds 
they are not, as a rule, as efficient as the ordinary reciprocating 
engine. 

Steam Consumption. — When running at their designed speed 
turbines use about 11.85 lb. of steam per shaft horse power, while 
reciprocating engines use about 13.65 lb. per i. h. p. 

Weights. — With turbines there is a saving of weight chiefly due 
to a decrease of 15 to 20% of the boiler capacity required for full 
power, owing to the increased economy of turbine machinery. There 
is also a saving in weight over those of reciprocating engines and in 
the space occupied. 



Digiti 



zed by G00gk 



HORSE POWER 



447 



Comparative Performances of Different Systems of Pro- 
pulsion 



Losses Given in 
Per cent of Total 
Power Developed 


Turbine 
Connected 
Direct to 
Propeller 
Shafting 


Turbine 

Drive 

Through 

Mechanical 

Reduction 

Gear 


Turbine 

and 
Electric 
Trans- 
mission 


Turbines 
and 

Hydraulic 
Trans- 
mission 

Fottinger 
Type 


Combination 
—2 Recipro- 
cating 
Engines 
and 1 Low- 
Pressure 
Turbine 


Turbine water rates, lb. per 
s. h. p. hour 

Mechanical reduction gear 
losses 

Generator and motor losses. . 

Hydraulic transformer losses 

Reciprocating engine losses 
in combination 

Losses in thrust line and pro- 


11H to 12 

VA% 

53% 

22 to 23 


WA to 11 

2% 

2H% 

65% 

17 to 17.7 


lOHtoll 

Vo'%' 

2H% 

65% 
18.4 to 19.3 


lOHtoll 

*14%" 

2H% 

60% 

20.8 to 21.9 


10H to 11 

5.3% 

2K 2 % 

60% 

19 to 19.9 


Propulsive efficiencies 

Water rate, lb. per e. h. p.. . 



See also the table, Pounds of Steam to Main Engines per Hour per Effective Horse Power. 
See also the table, Comparative Performances of Geared Turbines and Reciprocating Engines. 

Horse Power. — To calculate the horse power of a turbine an in- 
strument called a torsion meter is used, which measures the tor- 
sional movement of the propeller shaft. 

Let C — pounds per square inch, being the coefficient of rigidity 
depending on the material of the shaft 
torsion or turning movement on shaft in foot-pounds 
angle of . distortion in circular measure between the 
two points on the shaft which were originally in the 
same straight line parallel to the shaft axis 
distance in feet the points are apart 
moment of inertia of the shaft cross section in inch 
units when calculated from the dimensions of the shaft 

by the formula J a — — (di 4 — d 2 4 ) where d x and d 2 

are the external and internal diameters of the shaft. 

rdi* 



F 

e 

L 
/a 



If the shaft is solid then J ft = 



32 



N = revolutions of shaft per minute 

F = the torsion or turning movement on the shaft in foot- 
C X 7 a X e 



pounds = 



144 X L 



Hence the shaft horse power (s. h. p.) = 33^55 X 144 * L 

Digitized by VjiX3O0^lC 



448 MACHINERY 

Or the horse power may be calculated if the steam consumption, 
heat drop per pound of steam, and turbine efficiency are known — 
thus: 

calculated shaft horse power = 

lbs, of steam per min. X heat drop X 778 X turbine efficiency . 

33000 
The shaft or brake horse power is usually taken as .9 of the 
indicated. 

A XS X P 



Then s. h. p. — 



11.85 



To Find the Quantity of Steam used in Pounds per Shaft Horse 
Power. 

Q = quantity of steam used in pounds per shaft horse 

power 
A = available heat in B. t. u.'s per pound of steam within 

a certain pressure limit Pi — P 2 
E -* efficiency, which in marine turbines is from 55 to 65% 
ft. lbs, per hour 1,980,000 

Inen Q A X 77S X E A X 778 X E 
Auxiliaries. — These are practically the same as for steam engines 
with slight modifications, the chief being in the condenser, as a 
greater steam volume issues from a turbine since it operates at a 
higher vacuum than a steam engine. The condensers are invari- 
ably of the contraflow type, the steam and cooling water circulating 
in opposite directions. 

A large circulating pump is required, and besides the usual air 
pump a dry vacuum pump is often installed. Sometimes, instead 
of the dry vacuum pump there is a vacuum augmenter, the chief 
purpose of which is to condense the vapor and draw off the air from 
the main condenser. 

On account of the high speed at which turbines run, an efficient 
oiling system is essential. The oil is supplied by forced lubrication 
at pressures varying from 15 to 35 lb. to the turbine bearings as 
well as to the line shaft bearings. 
See section on Auxiliaries. 

STEAM PLANT AUXILIARIES 

Atmospheric Pressure. — At sea level the pressure of the atmos- 
phere varies from 14.5 to 15 lb. per square inch, a fair average being 
14.7. Atmospheric pressure is measured by the barometer. 

Digitized by vjOOQ I 



GAUGE PRESSURE . 449 

Gauge Pressure is pressure measured above that of the atmos- 
phere. Ordinary steam- gauges indicate pressures above the 
atmosphere. 

Gross or Absolute Pressure is the gauge pressure plus the at- 
mospheric. 

Vacuum, see Vacuum and Vacuum Gauge. 

Thermodynamics of Condensers. — To condense steam, its latent 
heat of evaporation must be transferred to a sufficient weight of 
water cold enough to absorb the heat. At 90° F., which corre- 
sponds to an absolute pressure of 1.42 ins. of mercury or 28.58 ins. 
of .vacuum referred to a 30-in. barometer, steam contains about 
1,040 latent heat units (B. t. u.) per pound. If this heat is trans- 
ferred to water entering the condenser at 60° and the water thereby 
heated to 90°, which is the utmost possible with 90° steam, each 
pound of water will absorb 30 B. t. u. Therefore, for each pound 

of steam condensed there will be required ~^r- = 34.7 lb. of water 

ok) 

as the least quantity theoretically possible to condense the steam. 

If the water enters at 70°, each pound can only absorb 20 B. t. u., 

1040 
and 9 = 52 lb. of water which will be required per pound of 

steam. For example, suppose a 10,000 kw. turbine, or engine and 
turbine plant uses 15 lb. of steam per kw. hour. If the average 
summer temperature of the cooling water is 70° and a steam 

temperature of 90° is specified at that season, then — '- ^ — 

Ay) 

= 7,800,000 lb. of cooling water per hour, theoretically required. 

As the cooling water in actual practice never rises fully to the 
temperature of the steam, it is necessary to allow for a certain 
temperature difference between the outgoing water and the steam. 
In most instances condensers are designed for a difference or tem- 
perature head of 5° F. or over, depending on the steam and on 
the. temperature of the incoming water, but being greater for a 
low vacuum (where less water is handled) than for a high, and 
greater in winter than in summer. 

Owing to condensation in the turbine, due partly to radiation 
and partly to expansion, the steam exhausted into the condenser 
must contain a certain amount of moisture ranging from 5 to 15%; 
that is, the steam gives up part of its latent heat before it reaches 
the condenser. It is therefore sufficiently accurate to assume that 
the condenser receives 950 B. t. u. per pound of steam used at the 

Digitized by VjiOOQ 1C 



450 . MACHINERY 

throttle when the latter reaches the turbine saturated, and 1,000 
B. t. u.'s when it is moderately superheated. 

The smallest quantity of water will be required when the cooling 
water leaves the condenser at a temperature as close as possible to 
that of the entering steam. No condenser produces a perfect vacuum. 
A closed vessel exhausted completely of air and partially filled 
with water contains water vapor whose pressure will depend on its 
temperature. For a temperature of 60° F. it is .52 in. of mercury, 
or 29.48 ins. of vacuum referred to a 30-in. barometer; for 80°, 
1.029 ins. of mercury and so on. In a steam condenser there is 
always present a certain amount of air in addition to the water vapor. 
Some of this is carried through with the steam from the feed water; 
a large quantity is added by leaks around the piston rod and valve 
stem of the low-pressure cylinder of reciprocating engines, or it is 
admitted through the shaft stuffing boxes of turbines, also by air 
leaks in the joints of the exhaust pipe. In jet condensers a third 
source of air, larger than either of the others, is the cooling water 
itself, whose absorbed air is set free by the reduced pressure and 
increased temperature in the condenser. (Notes from C. H. 
Wheeler Mfg. Co., Philadelphia, Pa.) 

Condensers convert the exhaust steam from the engine and 
turbine into water. There are three types, viz., jet, surface, and 
keel. The former consists of a cone-shaped chamber in which 
the steam and cold condensing water are mingled, the steam giving 
up its heat to the relatively cool water, and being reduced to the 
liquid state again. The condensing water enters at the top of the 
chamber and falls upon a plate pierced with a large number of 
small holes and known as the scattering plate. The condensed 
steam and condensing water fall together to the bottom of the 
condenser and are pumped by the boiler feed pump to the boilers. 
Should there be a superfluous amount this is discharged overboard 
by another pump. It is evident that jet condensers can be installed 
only in vessels running on freshi water. See also Jet Condensers. 

Surface Condensers are cylindrical or rectangular in shape. 
When the latter they may form part of the frame supporting the 
engine cylinders. In either case they contatin a large number of 
small brass tubes, fastened at each end to tube sheets. The con- 
densing water is driven by a circulating pump (generally a cen- 
trifugal one) through the tubes, the water being drawn from the sea. 
The steam entering the condenser at the top comes in contact 
with baffles or diaphragm plates preventing it from rushing through 

Digitized by VjOOQ 1C 



FEED WATER HEATER 



451 




Digiti 



zed by G00gk 



452 



MACHINERY 



the condenser to the bottom and causing it to be broken up and to 
pass around the tubes through which the cold water is flowing, 
thus condensing the steam into water which is pumped to the hot 
»*well by an air pump. The coldest water usually enters at the bot- 
tom, meeting the steam at the lowest temperature, and the warmest 
water at the top comes in contact with the tubes which are sur- 
rounded by the hottest steam. The cooling water often flows 
through the condenser two or three times, and travels in an oppo- 
site direction to the steam. 

Sizes op Surface Condensers, Air and Circulating Pumps 



Size of 
Engine 



17 X 27 X 43 



24 



Twin 

17 X 27 X 43 



24 
25 X 41 X 68 



4? 

24 X 40 X 63 



49>4 
20 X 33 X 54 



40 
29 X 49 X 84 



54 

Triple screw 
turbine, to- 
tal s.h.p. 
25,000 



Cooling 
Surface in 
Condenser 
in Sq. Ft. 



1,350 



2 cond. total 
cooling sur- 
face, 2,750 



4,500 



3,000 



1,563 



6,800 



2 cond. each 
13,046 



Air Pump 



Independent — 2 single acting cylinders 
— steam 1Yi ins. dm., 2 air cylinders, 
16^ ins. dia. by 10-in. stroke. 

One air pump for the 2 condensers, 
12 in. dia. steam cylinder with 2 20-in. 
buckets with stroke of 12 ins. 



Vertical duplex Blake, 10 X 22 X 25 



23% in. dia. X 23% in. stroke. 



20 ins. dia. X 14-in. stroke 



ins. dia. X 24-in. stroke 



One pump for each cond., twin beam, 
vert., single acting Blake — air cylin- 
ders, 32 ins. dia., steam 14 ins. dia. by 
21 ins. stroke. 



Circulating Pump 



Centrifugal, 8-in. sue, 
8-in. dis. engine, 7X7 

2 circulating pumps, 
one for each cond., cen- 
trifugal, 8-in. sue, 8-in. 
dis., engine 7X7 

Cent., 10-in. sue., 10-in. 
dis, engine 12 X 10 



14-in. dia. X 23%-in. 
stroke. 



Cent., 9-in. sue., 8-in. 
dis., engine 7X7 



Cent., 12-in. sue, 12-in. 
dis., engine 9 X 10 



Cent, pump, 26-m. sue, 
26-in. dis. 



Structural Features of Surface Condensers. — In modern ships 
with triple expansion engines the area of the cooling surface in a 
condenser is from 1 to 1.25 sq. ft. per i. h. p. In warships, 1 sq. ft. 
per i. h. p. has been found sufficient. With steam turbines where 
a higher vacuum can be more advantageously utilized than with 
reciprocating engines, the cooling area may be 1.2 sq. ft. per shaft 



nvJ^v^ 



OPERATING 463 

horse power for turbine warships. In torpedo boats the area is 
sometimes as low as .75 sq. ft. 

The shells are made of cast iron, sheet brass, or steel plates. 
The tubes are of thin brass, usually J^ to jfr£ inch outside diameter. 
They are fastened to tube sheets by ferrules which by screwing 
down compress a packing, thereby making a watertight joint. 

Surface condensers are provided with the following fittings and 
connections:' 

Main air pump suction 

Suction from some fresh water pump, as hot well pump, for keep- 
ing condenser clear when main engines are stopped 

Drain cocks for both salt and fresh water ends 

Air cocks to allow any accumulation of air to escape 

A boiling out connection so steam can be admitted to boil out 
the condenser 

A connection for admitting soda in solution 

A vacuum gauge and a water gauge 

Zincs are fitted in the salt water side and should have a good 
metallic contact with the heads 

Hand holes. Connection for making up feed from fresh water tank. 

Operating.* — To remove grease and dirt which accumulates on 
the outside of the tubes, the condenser should be boiled out. This 
is done by admitting potash or soda through the soda cock, the 
soda being first dissolved in water. Live steam is then turned 
into the condenser through the boiling out eonnection. The mix- 
ture of soda and steam dissolves the grease, forming a soapy sub- 
stance which can be drained off. Additional Water is introduced 
to wash away the accumulation and remove the extra soda. 

The vacuum may be lost through the following causes: 

Head or bucket valves of air pump broken; 

Injection pipe stopped up; 

Division plate in condenser door carried away; 

Leaky low pressure gland; 

Leaks in shell and joints. 

To find the probable cause of the loss of vacuum feel both ends 
of the condenser. If both are cold, the air pump valves are broken 
or there is a leaky low-pressure gland. If both are warm, either 
a broken circulating pump valve or a choked injection valve is 
the cause. If one end is cold and the other warm, the division 
plate in the condenser door is most likely carried away. 

* Abstracts from Care of Naval Machinery. H. Dinger. 



16 



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454 



MACHINERY 




Figure 76. — Piping of Condenser and Feed Tank — with a Radojet air pump *j 
installed. 



To locate quickly a leak in a condenser, take off the handhole 
plates at one end and start up the air pump. Hold a lighted candle 
around the tube ends. Where the flame is drawn in there is a 
leak, and such tubes should have their glands set up; or if it is the 
tube that leaks, it should be plugged by screwing in a metal plug 
or driving in a wooden one. 

Vacuum and Vacuum Gauge. — A vacuum gauge or Bourdon's 
tube is graduated in inches of mercury and indicates the difference 
between the absolute pressure on the inside of the tube and the 
atmosphere. As the pressure in the condenser is independent of the 
atmospheric, the vacuum registered will vary with the height of the 
barometer. Suppose the absolute pressure in the condenser cor- 
responds to 3 ins. of mercury. If the barometer is at 30 ins., the 
vacuum gauge would indicate 30 — 3 = 27 ins., or if the barometer 
was at 28 ins., the gauge would indicate 28 — 3 = 25 ins. 



y Google 



TO FIND THE VACUUM 



455 



In reciprocating engines only a slight gain is obtained thermo- 
dynamically in a vacuum above 26 ins., owing to increased cylinder 
condensation caused by the difference in the inlet and outlet tem- 
peratures of the steam. If the condenser is tight and the air pump 
in good condition, 26 ins. should be maintained even in hot weather. 

In turbines 28 to 29 ins. are obtainable, and with a Parsons 
vacuum augmenter installed the vacuum is one inch less than the 
barometer reading. 

To Find the Vacuum under Given Working Conditions. — If the 
temperature of the condenser is 101° F., and the barometer stands 
at 30 ins., equivalent to a pressure of 14.7 lb. per square inch, the 
vapor pressure corresponding to 101° (see table below) is .980 lb. 
per square inch; thus the greatest vacuum possible would be 14.7 
— .980 = 13.72 lb. per square inch below the atmosphere, equiva- 
lent to 27.5 ins. on the vacuum gauge. 



Vacuum 


Absolute 


Absolute' 


Tempera- 




Sensible 


Total 


Meas- 


Pressure 


Pressure 


ture of 


Latent 


Heat of 


Heat of 


ured in 


in 


in Pounds 


Boiling 


Heat of 


Evaporation 
from 


Evapora- 


Inches 


Inches 


per 


Point 


Evaporation 


tion from 


of 


of 


Square 


in 


in 


32° F. in 


32° F. in 


Mercury 


Mercury 


Inch 


Degrees F. 


B. t. u. 


B. t. u. 


B.t.u. 


29^ 


a 


.245 


59.1 


1072.8 


27.1 


1100.0 


29 


i 


.490 


79.3 


1058.8 


47.3 


1106.1 


2sy 2 


IH 


.735 


92.0 


1049.9 


60.1 


1110.0 


28 


2 


.980 


101.4 


1044.4 


69.5 


1112.8 


27 


3 


1.470 


115.3 


1033.7 


83.4 


1117.1 


26 


4 


1.96 


125.6 


1026.5 


93.8 


1120.3 


25 


5 


2.45 


134.0 


1020.6 


102.2 


1122.8 


24 


6 


2.94 


141.0 


1015.7 


109.3 


1125.0 


23 


7 


3.43 


147.0 


1011.5 


115.3 


1126.8 


22 


8 


3.92 


152.3 


1007.8 


120.2 


1128.4 


21 


9 


4.41 


157.0 


1004.5 


125.4 


1129.8 


20 


10 


4.90 


161.5 


1001.3 


129.9 


1131.2 


19 


11 


5.39 


165.6 


998.4 


134.1 


1132.4 


18 


12 


5.88 


169.2 


995.9 


137.7 


1133.5 


17 


13 


6.37 


172.8 


993.4 


140.3 


1134.6 


16 


14 


6.86 


176.0 


991.1 


144.5 


1135.6 


15 


15 


7.35 


179.1 


988.8 


147.7 


1136.5 


14 


16 


7.84 


182.0 


986.9 


150.6 


1137.4 


12 


18 


8.82 


187.4 


983.1 


156.0 


1139.1 


10 


20 


9.80 


192.3 


979.6 


161.0 


1140.6 


5 


25 


12.25 


203.0 


972.1 


171.8 


1143.9 





30 


14.70 


212.0 


965.7 


180.9 


1146.6 



14.7 lb. — atmospheric pressure — 30 inches of mercury. 
Table from Marine Steam Engine. R. Sennett and H. J. Oram. 

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456 



MACHINERY 



Vacuum and Corresponding Steam Temperature in Condenser 




Temperature 




Temperature 


Vacuum 
inches 


(Fahrenheit) 
degrees 


Vacuum 
inches 


(Fahrenheit) 
degrees 


20 


161.5 


26 


125.4 


21 


157.0 


26^ 


120.4 


22 


152.2 


27 


115.1 


23 


146.8 


27H 


108.6 


24 


140.8 


28 


101.2 


25 


133.7 


28}£ 


91.8 






29 


79.1 



Miscellaneous Notes. — The pressure in the condenser can be 
determined from the hot well temperature by noting the hot well 
temperature and looking in the table of saturated steam for the 
corresponding pressure. 

Example. The temperature of the water in the hot well is 141°. Find the pres- 
sure in the condenser. 

On looking up in the table of Saturated Steam, the pressure at this tempera- 
ture is 3 lb. absolute, which is then the pressure in the condenser. 

The actual pressure on the low-pressure cylinder is from 1 to 
2 lb. in excess of this, as a difference of pressure must exist for the 
steam to flow. Thus it is impossible to have a high vacuum and hot 
well temperature at the same time, as the two vary in inverse ratio. 
With a high temperature of the hot well water the vapor corre- 
sponding to the temperature is also high with a proportionally 
reduced vacuum in the condenser. 

Under ordinary conditions and with 25 to 26 ins. of vacuum, 
the temperature of the condenser discharge should be about 110° F. 
A lower temperature would indicate that an unnecessary amount 
of water is being pumped. See table under Circulating Pump. 

It is estimated that 20 volumes of water absorb one volume 
of air; hence if means were not taken tp remove this air from the 
condenser, it would fill it and destroy the vacuum. For this reason 
dry vacuum pumps are installed. 

One square foot of cooling surface in a surface condenser is allowed 
to condense 10 lb. of steam with the temperature of the circulating 
water at 70°, based on obtaining a vacuum of 25 ins. 

Jet Condensers. — The capacity of a jet condenser should not 
be less than one-fourth of the cylinder or cylinders exhausting into 
it, one-third the capacity being generally sufficient. The objection 

Digitized by vjOOQ 1C 



COOLING WATER REQUIRED 457 

to a large condenser, besides its cost and weight, is that a longer 
time is necessary to get a good vacuum. See Condensers. 

With a jet condenser a vacuum of 24 ins. is considered fairly 
good, and 25 good. The temperature corresponding to 24 ins. 
or 3 lb. absolute pressure is 140°. In actual practice the tem- 
perature in the hot well varies from 110° to 120° and sometimes 
130° is maintained by a careful engineer. 

To Calculate the Quantity of Cooling Water Required for Either 
a Surface or a Jet Condenser.* 

Let T\ - temperature of steam entering the condenser 
L — the latent heat of the steam 
To — the temperature of the circulating water 
Q = the quantity of circulating water 
Ti = temperature of the water leaving the condenser 
Tz = temperature of the feed water 
The heat to be absorbed by the cooling water is (T\ + L) — Tz 
and is equal to 966 + .7 X 212° + .3 (T 2 - T ) or Q (T 2 - T ) w 
Hence Q (T 2 - T Q ) = (T y + L) - Tz 

_ 1114 + .3 Tj - Tz 
V T 2 - To 

Example. To find the amount of circulating water required by an engine with 
an exhaust at 8 lb. absolute pressure, the temperature of the sea being 60°. Also 
find the amount of water required when the sea temperature is 75°. The tem- 
perature of the water at the discharge is 100°, and of the feed 120°. The tem- 
perature corresponding to 8 lb. is 183°. 

At 60° 

1114 4. 9 y 183° 120° 

q = i'oq*-- eiy* — = 2622; that is ' the water re< i uired is 26 22 

times the weight of the steam. 
At 75° 

_ 1114 + .3 X 183° - 120° 
Q 100° - 75° 4195 time8 - - 

The quantity of sea water will depend on its initial temperature, 
which in actual practice varies from 40° in the winter of temperate 
zones to 80° in the West Indies and tropical seas. In the latter 
case a pound of water requires only 20 thermal units to raise it 
to 100°, while 60° are required in the former. Thus the quantity of 
circulating water required in the tropics is three times that required 
in the North Atlantic in the spring of the year. 

A rough approximation is 27 lb. of circulating water for every 

* From Practical Marine Engineering. 



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$T£AM 



^(jcr/ort 




D/SC#AfiK?C 



Figure 77. — Air Pump (Worthington Pump Co., New York). 

458 



OUTBOARD CONDENSERS 469 

pound of steam condensed. About 25 gallons of water are required 
to condense the steam represented by one gallon of water evap- 
orated, or one to one and a half gallons per minute per one h. p. 
Jet condensers do not require so much water for condensing as 
surface condensers. 

Keel or Outboard Condensers consist of pipes on the outside 
of the hull near the keel, into which the engine exhausts. They 
are often installed in launches, tugs, lighters, and small passenger 
steamers, and are of iron, brass, or copper pipe with an air pump 
operated by the engine — or, instead, the air pump may be inde- 
pendently steam driven. Neither copper nor brass should be used 
for keel condensers on vessels running in salt water, unless the 
stern bearing, propeller wheel, and tail shaft are of bronze. Neither 
should iron nor steel pipe be used if the vessel is coppered or has a 
bronze outboard bearing. 

Air Pump. — The function of an air pump is to draw out the air 
and water from a condenser and by the vacuum formed reduce the 
back pressure on the low-pressure piston. The air pump is often 
driven direct from the main engine, or it may be separate, having 
its own steam cylinder. 

There are two types, viz., single- and double-acting. The former 
is vertical and is usually selected. In the single-acting there is 
a reciprocating bucket or piston with orifices covered by non-return 
valves which move in a cylindrical barrel at each end of which 
are covers with orifices and non-return valves. These three sets 
of valves lift vertically and allow the passage of water or air in 
only one direction. The suction pipe of the air pump communi- 
cates with the bottom of the condenser, the pump being placed 
lower than the condenser to get the most satisfactory results. The 
valves at the lower end are called foot or suction valves, those in 
the moving bucket, bucket valves, while those in the top are the 
head or discharge valves. 

The stroke of a vertical air pump when driven from the main 
engine is \i to % that of the engine, but its speed should not exceed 
300 ft. per minute, and for continuous running should be about 
275 ft. 

Edward's air pump is a single acting vertical pump with valves 
only at the top to check the discharged water and air from returning 
to the pump on the down stroke. This pump is very simple and 
gives a good vacuum. See Fig. 78. 

Double-acting air pumps are of the horizontal type and have an 
* 



460 



MACHINERY 



efficiency ranging from 30 to 50%, a fair average being about 35. 
Single-acting, 40 to 60% with an average of 50. 

The capacity of an air pump is generally taken as ^ to ^ of the 
capacity of the low-pressure cylinder. One authority, Mr. Le 
Blanc, states that for turbines with a 29-inch vacuum the air pump 
must handle 21 times the volume of feed water, and for a recipro- 
cating engine with a 26-inch vacuum the pump must handle 12 times 
the volume of water. 



"S^^ 




EDWARDS AIR PUMP 
£8 NOVY EXIEN8JVELY U8EJ) ON MERCHANT 8HJP^ 



Figure 78. 



Independent from main engine, vertical twin-cylinder air pumps 
for jet and surface condensers, having 2 steam and 2 water cylinders, 



jvJ^v^ 



AIR CIRCULATING PUMPS 



461 



are given in the following table. The pumps are single-acting, 
and the capacities given are the capacities per revolution for each 
side; for a complete revolution the capacity is twice that per side. 
The pumps can be run at 100 ft. per minute, but for constant a 
speed of 75 ft. or less is recommended. 



■•^ 


r 










Steam 

Cylinders, 

Inches 


Air 

Cylinders, 

Inches 


Stroke, 
Inches 


Gallons 
per Stroke 


Steam 
Pipe, 
Inches 


Exhaust 
Pipe, 
Inches 


8 


16 


12 


10.44 


m 


2y 2 


10 


16 


12 


10.44 


VA 


2H 


• 12 


16 


12 


10.44 


1% 


3 


8 


18 


12 


13.22 


m 


2H 


10 


18 


12 


13.22 


m 


2*A 


12 


18 


12 


13.22 


m 


3 


10 


20 


12 


16.32 


im 


2y 2 


12 


20 


12 


16.32 


2 l A 


3 


10 


22 


15 


24.68 


iH 


2M 


12 


22 


15 


24.68 


2H 


3 


14 


22 


15 


24.68 


2i4 


3 


12 


24 


18 


35.25 


•2H 


3 


14 


24 


18 


35.25 


2M 


3 


12 


30 


18 


55.08 


2H 


3 


14 


30 


18 


55.08 


2H 


3 


16 


30 


18 


55.08 


3 


3M 


14 


36 


18 


79.32 


2^ 


3 


16 


36 


18 


79.32 


3 


3H 


18 


36 


18 


79.32 


Wi 


3H 


16 


38 


20 


98.20 


3 


VA 


18 


38 


20 


98.20 


zy 2 


VA 


20 


38 


20 


98.20 


W 2 


VA 


18 


40 


24 


130.58 


W 2 


3A 


20 


40 


24 


130.58 


W 2 . 


m 


24 


40 


24 


130.58 


4 


4 


24 


48 


24 


188.04 


4 


4 


30 


48 


24 


188.04 


VA 


4^ 


30 


58 


24 


274.00 


4^ 


4^ 



Dean Bros., Indianapolis, Ind. 

See table of Sizes of Condensers, Air and Circulating Pumps. 

A new type of air pump (trade name Radojet, C. H. Wheeler 
Mfg. Co., Phila., Pa.) is shown in Fig. 76. This pump is a substitute 
for any air pump working on the dry air principle. It has no 
piston nor valves, and is operated by live steam jets which by 
passing through nozzles of patented design obtain a high velocity 
that entrain the air and non-condensable gases from the condenser. 



Digitized 



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462 MACHINERY 

The ordinary reciprocating air pump may be replaced by a Radojet 
removing the air, while a small, direct acting, hot well pump removes 
the condensed steam from the condenser. The arrangement is practi- 
cally the same for either reciprocating engines or turbines, only in 
the latter a direct acting duplex reciprocating pump is employed 
for removing the condensed steam from the condenser. 

Circulating Pump. — This forces the cooling water through the 
condenser tubes, and is either of the reciprocating or centrifugal 
type; if the latter, is driven by a steam engine running at about 
200 revs, per minute or it may be driven by a turbine at a higher 
speed. The water should be pumped through the tubes at a velocity 
of about 115 ft. per minute, when the sea water is at 60°, and 170 
ft. when at 75°, the speed of the pump being so regulated that the 
temperature of the discharge water is about 20° below the tem- 
perature corresponding to the vacuum that is to be maintained. 



Vacuum, 
Inches 



Temperature of Discharge Water Corresponding 
to Vacuum, Degrees 



28 
26 
24 
22 
20 



100 
125 
140 
152 
161 



If the circulating pump breaks down, connect up the donkey 
pump to the condenser for circulating the water, but if this cannot 
be done, or if no other pump can be connected up, then the engines 
must be run jet condensing if the steamer runs in fresh water, or 
non-condensing if in salt water. To do this draw a number of the 
condenser tubes, and open up the air pump discharge valve. To find 

thenumberof tubes todraw, use theformula ConS^tXlh^ S 

= number of tubes. 

See section on Pumps; also table of Sizes of Condensers, Air 
and Circulating Pumps. 

Feed and Filter Tank (Hot Well).— The air pump discharges 
the condensed water from the condenser into a combined feed and 
filter tank. In large vessels this tank has sufficient capacity for 
10 to 15 minutes running at full boiler power. The tank is divided 
into several compartments. See Fig 76. 



Digitized 



by Google 



FILTERING MATERIALS 



463 



As to filtering materials, coke in bags of burlap or heavy toweling 
is fairly satisfactory. When the coke is to be renewed the bags 
are washed with soda and refilled with fresh coke. 

Zincs are suspended in the feed tanks to absorb oxygen. 

Steam Traps. — As steam condenses in the pipes through which 
it passes it is necessary to drain the condensed water off, and this 
is accomplished by pipes leading to traps where the water is col- 
lected and from which the water goes to the filter tank for use over 
again in the boiler. 

The best way to specify the size of a trap is to specify the size 
of the orifice in the valve and the maximum pressure the trap 
will work under. The orifice in the valve is always the capacity 
of the trap and no more condensation can pass through the trap 
than will pass through the orifice, regardless of the size of the pipe 
connections. Hence the only accurate way of deciding on a steam 
trap for any service is to know its discharge capacity in pounds 
or gallons per hour. 

Under ordinary conditions 9 ounces of condensation per linear 
foot of one-inch pipe per hour are allowed. To compute the equiv- 
alent in one-inch pipe of a given quantity of pipe of other sizes, 
multiply the number of linear feet of a certain size by the figure 
underneath that size, as in the table below. 



Size of Pipe, Ins. 


\k 


m 


2 


2H 


3 


3H 


4 


4H 


5 


6 


7 


8 





10 


12 


Multipliers..... 


1.26 


1.44 


1.81 


2.19 


2.66 


3.04 


3.42 


3.80 


4.23 


5.43 


5.80 


6.55 


7.34 


8.18 


9.72 



To find the rated allowance of condensation in ounces per linear 
foot per hour of any steam trap, take the rated discharge capacity 
in pounds per hour, and compute same in ounces; then divide 
by the number of rated linear feet and the result is the allowance 
of condensation per linear feet per hour. 

The rating in feet of one-inch pipe of a steam trap, based on 
a fixed amount of condensation per foot per hour, will be materially 
reduced when the condensation is severe, say 25 ounces of conden- 
sation per foot per hour. 

To determine the number of linear feet a trap will take care of, 
compute the capacity of condensation in pounds per hour and then 
in ounces; next decide on the allowance of condensation per foot 
per hour and divide it into the capacity. The quotient will be the 

Digitized by vjOOQ 1C 



464 



MACHINERY 



number of linear feet. Thus suppose a trap is rated at 4,380 lb. 
per hour and the allowance per foot of one-inch pipe is 25 lb.; then 

4,380 lb. per hour (capacity) 
16 



70,080 oz. per hour, 
70,080 



25 



= 2,803 linear feet of 1-inch pipe 




Figure 79.— Feed Water Filter. 



Feed Water Filter. — Referring to the filter in Fig. 79 (Ross Valve 
Co., Troy, N. Y.) the water enters the right hand pipe at the top 
and flows into the chamber below. The central portion of the 
chamber is occupied by the filter. The filtering material is known 
as linen terry or Turkish toweling. The toweling is over a bronze 



nvJ^v^ 



FEED WATER HEATERS; [465 

circular frame, the filtering surface being from 150 to 1000 times 
the area of the feed pipe according to the service required. When 
a feed water heater is used, water should first pass through the 
filter. 

Feed Water Heaters. — These are either open (jet) or closed 
(surface). Open heaters consist of a closed chamber into which 
the feed water is delivered by a pump. In this chamber it overflows 
a series of trays and condenses the exhaust steam in the same 
manner as a jet condenser. The resulting hot water is pumped by 
the boiler feed pump to the boiler. With this type the temperature 
of the feed water cannot be above about 180°, as a higher tempera- 
ture would cause vapor to - form and the feed pump would not 
have a proper suction. 

The closed type of heater operates like a surface condenser. 
It consists of a cast iron chamber containing brass or copper tubes 
through which the water from the hot well is forced by the boiler 
feed pump on its way to the boiler. The space around the tubes 
is filled with exhaust steam (from the main units or the auxiliaries), 
the water entering the tubes either cold or at hot well temperature. 
When there is an excess of exhaust steam, the water goes to the 
boiler within a few degrees of the exhaust steam temperature. 
When the exhaust steam supply is limited, practically all is condensed 
in the heater, and its latent heat transferred to the water, thereby 
determining the resultant temperature of the water. Two systems 
are in use, one where the heater is on the suction side of the feed 
pump and the other where it is on the discharge side. With the 
heater on the suction side of the pump a hot well pump is needed. 
To get 220° temperature a pressure of around 5 lb. above the at- 
mosphere is necessary. ^Ordinarily a saving of one per cent, is made 
by each increase of 11° F. in the temperature of the feed water, 
which is about .09 per cent, per degree. That is, an approximate 
rise of 10° in the temperature of the feed water gives a saving of 
1 per cent, in the amount of coal used. An efficient heater will 
give the feed water a temperature within 10° of the temperature of 
the steam. 

Example. The temperature of the feed water entering a heater is 70° F., and 
on leaving 81°, steam 100 lb. at the gauge, containing 1,189 B. t. u. per pound. 
Find the saving in per cent if the temperature is raised 11°. 

Let H = total heat in one pound of steam at the boiler pressure 

Hv — total heat in one pound of feed water before entering the heater 
Ht — total heat in one pound of feed water after leaving the heater 



ioogle 




Figure 80.— Feed Water Heater. 



466 



Digitized 



by Google 



EVAPORATORS 



467 



\ 



Then per cent saved = jy _ i/ 



Temperature of feed water entering heater = 70° and oontains 70° — 32° — 
38 B. t. u. per lb. 

Temperature of feed water leaving heater » 81° and oontains 81° — 32° = 
49 B. t. u. per lb. 



Saving in raising temperature 11° — 



49-38 



Ht -Hi ______ 

H- Hi 1,189 -J 



- .96% 



Fig. 80 is of a feed water heater built by Schutte & Koerting, 
Phila., Pa., of concentric spiral corrugated tubes. This construction 
besides agitating the water and so preventing the formation of cold 
cores, keeps the water in a thin film between two heated copper 
surfaces. This gives an exceedingly high rate of heat transmission, 
and yet at the same time a light and efficient heater. The heater 
may be arranged either vertical or horizontal.. 

Percentage Saving in Fuel by Heating Feed Water With 

Exhaust Steam 

100 lb. Boiler Pressure 



Initial 
Temp. 


Final Temperature of Feed Water 


Initial 
Temp. 


of Feed 
Water 


120° 


130° 


140° 


150° 


160° 


170° 


180° 


190° 


200° 


210° 


220° 


230° 


of Feed 
Water 


°F. 
40° 
50* 
60* 

70* 
80° 
90° 

100° 
110° 
120° 

130° 


% 
6. 8 
5.95 
5. 1 

4.25 
3. 4 
2.55 

1. 7 
0.85 


% 

7.65 
6.85 
6.04 

5.23 
4.39 
3.54 

2.68 
1. 8 
0.91 


% 

8.72 
7.92 
7.12 

6.27 
5.43 
4.57 

3.68 

2.78 
1.88 

0.95 


% 

9.35 
8.57 
7.67 

6.97 
6.15 
5.32 

4.47 
3.61 
2.73 

1.84 
0.92 


% 
10.45 
9.70 
8.90 

8.07 
7.24 
6.40 

5.53 
4.65 
3.75 

2.84 
1.90 
0.97 


% 
11.05 
11.28 

9.50 

8.72 
7.91 
7.09 

6.26 
5.41 
4.55 

3.68 
2.98 
1.97 


% 
12.20 
11.45 
10.70 

9.87 
9.05 
8.22 

7.38 
6.52 
5.63 

4.74 
3.83 
2.90 


% 
13.07 
12.32 
11.60 

10.75 
9.95 
9.13 

8.30 
7.43 
6.58 

6.68 
4.80 
3.85 


% 
13.95 
13.20 
12.45 

11.65 
10.85 
10.05 

9.22 
8.38 
7.50 

6.63 
5.75 
4.83 


% 
14.80 
14.10 
13.35 

12.55 
11.75 
10.95 

10.15 
9.30 
8.45 

7.60 
6.70 
5.80 


% 
15.70 
15.00 
14.25 

13.45 
12.70 
11.90 

11.05 
10.25 
9.40 

8.55 
7.65 
6.75 


% 
16.55 
15.85 
15.15 

14.35 
13.60 
12.80 

12.00 
11.15 
10.30 

9.45 
8.60 
7.72 


°F. 
40° 
50° 
60° 

70° 
80° 
90° 

100° 
110° 
120° 

130° 


140° 






140° 


150° 








150° 















Evaporators are for treating salt water so that it can be used 
in the boilers. AH types work on the same principle; that is, the 
salt water is heated by steam from the boilers. The boiler steam to 
the coils of an evaporator is merely a medium for carrying heat to 
the apparatus, and is returned to the boiler as hot feed after it is 
condensed in the coils. The quantity of steam or coal required to 
produce a ton of distilled water depends on the temperature of the 



le 



468 



MACHINERY 



evaporator feed and the pressure of the steam in the coils. Neglect- 
ing radiation, there is always a loss in heating an evaporator, due 
to blowing down, but under ordinary working conditions this loss is 
only about 5%. 

The following table shows the pounds of boiler steam required 
to produce one pound of pure water at various pressures and feed 
temperatures, working single effect and under normal conditions, 
and neglecting radiation loss. The figures do not include steam 
used by feed pump or circulating pump. 



Boiler Steam Pressure 


Temperature of Feed Water 


to Coils 


50° 


75° 


100° 


125° 


150° 


175° 


200° 


225° 


75 lb 


1.30 
1.31 
1.32 
1.34 
1.36 
1.38 
1.41 
1.43 


1.26 
1.27 
1.29 
1.31 
1.33 
1.35 
1.37 
1.39 


1.22 
1.23 
1.25 
1.27 
1.29 
1.31 
1.33 
1.35 


1.17 
1.19 
1.21 
1.23 
1.25 
1.26 
1.28 
1.30 


1.14 
1.15 
1.17 
1.19 
1.20 
1.22 
1.24 
1.26 


1.10 
1.11 
1.13 
1.14 
1.16 
1.18 
1.20 
1.22 


1.06 
1.07 
1.09 
1.10 
1.12 
1.14 
1.15 
1.17 


1.03 


100 lb 


1.04 


125 lb 


1.05 


150 lb 


1.06 


175 lb 


1.08 


200 lb 


1.10 


225 lb 


1.11 


250 lb 


1.13 








Figure 81.— Piping of Distiller and Evaporator (M. T. Davidson 6 Co., New York). 

Digitized by VJiOOQLC 



DIMENSIONS OF EVAPORATORS 



469 







Dimensions of 


Evaporators* 














Diameter of Connections 




Size 


Diameter 
of Shell 


Height 
of Shell 












No. 


















Steam 


Vapor 


Feed 


Blow 


Drain 








Inlet 


Outlet 


Inlet 


Off 


from Coils 




Inches 


Ft. In. 


Inches 


Inches 


Inches 


Inches 


Inches 


1 


10 


5 


l A 


1 


• A 


X 


A 


2 


13 


5 


% 


IX 


A 


H 


A 


3 


15 


5 3 


l 


IX 


H 


% 


H 


4 


18 


5 6 


l 


IX 


*A 


H 


H 


5 


24 


6 


l 


134 


1 


l 


M 


6 


30 


6 6 


IK 


2 


IK 


l 


l 


7 


30 


6 6 


IX 


2 


1M 


l 


1 


8 


36 


7 


VA 


2V 2 


\A 


IK 


1 


9 


♦ 36 


7 


iy 2 


2V 2 


\A 


W 


1 


11 


40 


7 6 


2 


3 


2 


IX 


l 


12 


40 


7 6 


2 


zy 2 


2 


iVi 


l 


13 


45 


7 9 


2 


*y 2 


2 


w* 


lA 


14 


50 


8 


2V 2 


4 


2A 


l l A 


lA 


16 


60 


8 


2^ 


4 


2H 


1A 


\A 


17 


60 


8 3 


2Y 2 


4 


2A 


lA 


\A 



Capacities op Evaporators 







Tons per 


24 Hours 


Gallons per 24 Hours 




Size 


Diameter 
of Shell 










Weight 


No. 


«, 












Minimum 


Maximum 


Minimum 


Maximum 






Inches 










Pounds 


1 


10 


.83 




200 


.... 


200 


2 


13 


1.20 




300 




400 


3 


15 


2.08 


2.50 


500 


600 


548 


4 


18 


3.66 


4.17 


880 


1,000 


630 


5 


24 


5.00 


5.62 


1,200 


1,350 


960 


6 


30 


7.08 


8.33 


1,700 


2,000 


1,295 


7 


30 


8.54 


9.58 


2,050 


2,300 


1,450 


8 


36 


10.42 


12.08 


2,500 


2,900 


1,697 


9 


36 


13.33 


15.00 


3,200 


3,600 


1,830 


11 


40 


14.58 


16.67 


3,500 


4,000 


2,286 


12 


40 


18.75 


20.83 


4,500 


5,000 


2,600 


13 


45 


22.66 


25.62 


5,440 


6,150 


2,740 


14 


50 


27.92 


31.67 


6,700 


7,600 


3,558 


16 


60 


33.33 


37.50 


8,000 


9,000 


5,600 


17 


60 


45.00 


50.00 


10,840 


12,000 


5,845 



Minimum capacities represent quantity of pure drinking water; 
maximum capacities represent quantity of make-up boiler feed 
water. oigiti^dby >Ogr 

* Reilly multicoil evaporators, Griscom-Russell Co. 



470 MACHINERY 

As to the size to be installed, a fairly good rule is to allow one 
ton of water per day per 100 i. h. p. of the engine. The Reilly 
multlcoil evaporators (Griscom-Russell Co., New York) have a 
rated capacity based on a steam pressure of 75 lb. in the coils with 
a feed temperature of 75° and a pressure of 15 lb. maintained in 
the vapor space in the shell. Increase of steam pressure in the 
coils materially increases the capacity with slightly diminished 
efficiency. 

Feed water may be made by a single effect evaporator (that is, 
using only one evaporator), for only a nominal consumption of 
coal, preferably the drain from the coils is led to the hot well and 
the heat of the drain is saved. If the vapor from the shell is also 
led to the hot well and there condensed, this heat is also saved, 
and practically the only loss during the operation is due to blowing 
down and radiation. 

Another method that is not so economical is leading the vapor 
to the low-pressure casing of the main engine. The least econom- 
ical method is to lead the vapor direct into the main engine condenser. 

The figures given below show the efficiency of the three methods. 
To produce 2,000 lb. of feed water witfci good coal, neglecting radi- 
ation, would require: 

Vapor leading to hot well or feed water heater 15 lb. of coal 

Vapor leading to low-pressure cylinder 175 lb. of coal 

Vapor leading to main engine condenser 235 lb. of coal 

Sometimes evaporators are used in multiple effect as by installing 
three, viz., high-pressure, intermediate, and low. 

PUMPS 

There are two types, reciprocating and centrifugal, each being 
particularly adapted for certain conditions; the former where the 
water has to be lifted by suction say a distance of 20 ft. and the 
latter for delivering a large volume under a small head as in sup- 
plying the cooling water to a marine surface condenser. 

In reciprocating pumps the pressure or head depends directly 
on the steam pressure in the cylinder (omitting loss of head by 
friction and turns), and in centrifugal the theoretical head against 
which a pump can deliver is represented by the pressure in the water 
leaving the impeller plus the pressure due to converting the velocity 
energy of the water leaving the impeller into pressure. 

A pump should be located as near the water to be pumped as 
possible, and when pumping from the sea it should be placed below 

Digitized by VjOOQ IC 



SUCTION HEAD 471 

the water line so that the water may flow to it by gravity. All 
suction pipes from the sea must be fitted with a cock or valve and 
a strainer placed over the outboard opening. The cock or valve 
should be near the hull or attached to it, so that the suction pipe 
to the pump can be removed for renewal or repairs. In pipes dis- 
charging overboard, unless the pump is above the water line, check 
valves are installed in the pipes. 

When pumps are some distance above the water line, a foot valve 
is frequently placed in the suction. This is a check valve opening 
toward the pump and is put next the cock or valve attacheji to 
the hull. Its purpose is to prevent the emptying of the suction 
pipe while the pump is at rest. When pumps are below the water 
line a foot valve is not required. 

If drawing or forcing water long distances or at high speeds, the 
diameters of the pipes should be greater than the openings on the 
pump. 

Suction Head is the distance from the surface of the suction 
water to the center of the pump plus frictional resistance through 
the piping and fittings. The suction head should not exceed 25 ft. 

Discharge Head is the distance above the pump shaft up to 
the point of discharge plus frictional resistance in the pipe. To 
find the discharge head in feet, multiply the pressure by 2.31. 

„ T , , Gallons per minute X head in feet 
Water horse power = — — ^r^ 

««. . Water horse power _,-. . r ,. 

Efficiency = = — r — r - . Efficiency of reciprocating 

pumps varies from 60 to 70% and of centrifugal pumps 30 to 50. 

For estimating size of boiler feed pumps, the formula Gallons per 

Boiler horse power ... , 

minute = ig n could be used. 

lo.o 

Reciprocating Pumps. — Vertical reciprocating pumps are prefer- 
able to horizontal, for marine purposes, on account of the small 
horizontal space available on a vessel. The vertical type is exten- 
sively used for boiler feed, drainage systems, fire purposes, etc. 
Duplex pumps are practically two single pumps placed side by side, 
the valve movement of one pump being actuated by connections 
with the piston rod of the other. 

The height to which a pump will lift water depends on atmos- 
pheric pressure. One pound per square inch corresponds to a head 
of water of 2.309 ft. Therefore, to find the lift of a pump, multiply 

Digitized by VjOOQ IC 



472 MACHINERY 

the pressure per square inch, obtained from the barometer reading, 
by 2.309. 

Example. At sea level the barometer stands, say, at 30 ins., and the correspond- 
ing pressure is 14.72 lb. Thus the theoretical lift of a pump would be 14.72 X 
2.309 ft. = 34 ft. But in actual practice it requires a good pump to draw to a 
height of 28 ft. 

To find the discharge of a pump in gallons per minute, 

Let T = piston travel in feet per minute 

d = diameter of cylinder in inches 

G = number of U. S. gallons discharged per minute 

Then G = .03264 X T X & 

To find the horse power necessary to elevate water to a given 
height, multiply the total weight of the water in pounds delivered 
per minute by the distance in feet between the suction and discharge 
water level and divide the product by 33,000. To this quotient 25% 
should be added for water friction, and 25% for loss in steam^cylinder. 

The area of the steam piston multiplied by the. steam pressure 
gives the total amount of pressure that can be exerted. The area 
of the water piston multiplied by the pressure of water per square 
inch gives the resistance. There must be a margin between the 
power and the resistance to move the pistons at the required speed, 
say from 20 to 40% according to the speed and other conditions. 

The duty of a pump is the number of foot-pounds of work actually 
done by 100 lb. of coal burned. 

rr.u j A oop ro Gallons per min. X lift in ft. 

Thus duty = 835.53 w . , - . y . , -r-. -3- 

Weight of coal burned m pounds 

To find the quantity of water elevated in one minute, running 

at a piston speed of 100 ft. (a fair average) per minute, square 
the diameter of the water cylinder in inches and multiply by 4. 
Suppose the capacity of a 5-inch cylinder is desired; the square 
of the diameter is 25, which, multiplied by 4, gives 100, which is 
the approximate gallons per minute. 

To find the diameter of a pump cylinder to move a given quan- 
tity of water per minute (assume piston speed of 100 ft. per min- 
ute), divide the number of gallons by 4, then extract the square 
root, and the result will be the diameter in inches. 

Digitized by VjiOOQlC 



BOILER FEED PUMPS 473 

Single-Cylinder Horizontal Boiler Feed Pumps 











H.p. of Boiler, 


















Based on 30 Lb. 










Steam 


Water 


*§J 


Gallons 


, of Water per 


Steam 
Pipe 


Ex- 


Suc- 


Dis- 


Cylin- 


Cylin- 


11 


per 


H.p. per Hour, 


haust 


tion 


charge 


der 


der 




Stroke 


which the Pump 


Pipe 


Pipe 


Pipe 






• 




will Supply 
with Ease 










2K 


IK 


3 


.022 


12 




Ji 


X 


X 


K 


2K 


1% 


4 


.041 


20 




J* 


X 


1 


X 


3 


2 


4 


.05 


25 


8.2 


X 


H 


IX 


l 


3K 


2M 


4 


.069 


30 


H 


X 


K 


IX 


l 


4 


2K 


6 


.13 


60 


■si 

u ft 


H 


K 


IK 


IX 


4K 


3 


6 


.183 


85 


k 


% 


2 


IK 


5 


3Ji 


8 


.28 


135 


K 


X 


2 


IK 


6 


4 


8 


.435 


200 


S3 

9* 


x 


1 


2K 


2 


6 


4 


10 


.54 


250 


X 


1 


2K 


2 












Is 










7K 


5 


10 


.85 


400 


ll 


X 


1 


3 


2K 


8 


5Ji 


12 


1.12 


550 


5S eS 


l 


IX 


3 


2K 


9 


6 


12 


1.47 


700 


1 


IX 


4 


3 


10 


7 


12 


2.00 


1,000 




1 


IK 


5 


4 


12 


*X 


12 


2.77 


1,350 




IK 


2 


6 


5 


.12 


sx 


14 


3.23 


1,600 


IK 


2 


6 


5 


14 


9H 


16 


4.66 


2,250 




IK 


2 


7 


6 


14 


10 


14 


4.76 


2,300 


IK 


2 


8 


7 


14 


10 


16 


5.44 


2,700 


II 


IK 


2 


8 


7 


16 


10K 


18 


6.74 


3,300 


To 


2 


2K 


8 


7 


18 


11K 


18 


8.09 


4,000 


°4 

a-28 


2K 


3 


9 


8 


18 


11K 


20 


9.00 


4,500 


2K 


3 


9 


8 


18 


12 


20 


9.79 




isi 


2K 


3 


9 


8 


20 


13 


20 


11.49 


.... 


2K 


3 


10 


9 


20 


13 


22 


12.64 




'Us 


2K 


3 


10 


9 


22 


14 


24 


16.00 




2K 


3 


10 


10 


24 


15 


24 


18.36 




3K 


4 


10 


10 


24 


16 


24 


20.88 







3K 


4 


10 


10 



M. T. Davidson and Co., New York, 
drainage purposes. 



The above pumps could also be used for 



Hot water cannot be lifted by suction any desirable height, and 
the difficulty increases with the temperature. To handle hot water 
efficiently it should flow by gravity to the pump. 

Digitized by LiOOQ LC 



474 



MACHINERY 



Vertical duplex pumps, as given in the following table, have 
2 steam and 2 water cylinders. The water ends are of cast iron, 
composition lined, or may be entirely of composition. For boiler 
feeding these pumps have a speed of 30 to 50 single strokes per 
minute, but for other services they should be run at 60 to 80. 









Gallons per 




> 






Steam 


Water 


Stroke 


Single 


Steam 


Exhaust 


Suction 


Discharge 


Cylinder 


Cylinder 


Inches 


Stroke of 
Each Piston 


Pipe 


Pipe 


Pipe 


Pipe 


4 


2V 2 


4 


.084 


A 


Z A 


2 


1H 


4H 


3 


6 


.184 


A 


% 


*A 


2 


5 


3M 


6 


.249 


Va 


1 


3 


2M 


6 


4 


6 


.326 


1 


IK 


3 


2J4 


6 


4 


8 


.435 


1 


W± 


3 


2H 


7 


4H 


8 


.55 


1M 


1M 


4 


3 


8 


5 


10 


.85 


1H 


2 


4 


3H 


8 


5 


12 


1.02 


IV2 


2 


4 


3H 


9 


534 


10 


1.03 


m 


2 


VA 


4 


9 


6 


10 


1.225 


1H 


2 


5 


4K 


9 


6 


12 


1.469 


lA 


2 


5 


4M 


10 


7 


12 


2.00 


2 


2^ 


6 


5 


12 


8 


12 


2.61 


2 


2A 


7 


6 


12 


8M 


12 


2.94 


2 


m 


7 


6 


14 


9 


14 


3.85 


2M 


3 


7 


6 



M. T. Davidson and Co., Nek York. 

Centrifugal Pumps. — When the head for a centrifugal pump 
exceeds 100 ft. including the suction, one of the stage type should 
be installed. This consists of two or more impellers in separate 
casings mounted on the same shaft and so constructed that the water 
passes successively from one into the other, each impeller raising the 
pressure. 

Centrifugal pumps are often designated as low-lift and high-lift, 
and sometimes are called volute and turbine pumps, but in all 
the theory of operation is the same. 

For ordinary marine purposes a single-stage pump is sufficient 
and below is a table of direct connected centrifugal pumps of 
the volute type as built by the Worthington Steam Pump Co. 
Steam turbines and electric motors could be used instead of steam 



3UVJV^ 



CENTRIFUGAL PUMPS 



475 



engines if desired, particularly if the head is high, as steam engine 
driven pumps are suitable for comparatively low heads because 
of the limited speed of the engines which run at about 400 r. p. m. 
while turbines and motors run at 800 and over. On account of 
the small space occupied and light weight, turbine driven pumps 
have become popular. Besides handling the intake water for con- 
densers, they have also worked satisfactorily for boiler feeding 
and for fire purposes. 

One of the chief advantages of centrifugal boiler feed pumps 
is that they deliver a uniform pressure and volume at a given 
speed, eliminating the vibration in the unit and piping that is 
common with reciprocating pumps. Furthermore, the pressure 
being kept constant, a much lower margin of difference between 
the pump pressure and the boiler pressure is obtained than with 
reciprocating pumps. 

A volute pump has no diffusion vanes, whereas a turbine pump 
has, while its casing may be either of a spiral or a circular form. 



Centrifugal Pumps (Volute Type) Direct Connected to 
Steam Engines 

(Worthington Steam Pump Co., New York) 









Engine 








Pumps 


Dia. 


















Steam 


















Cyl. 


Stroke 


Rev. 


H.p. 


Steam 
Pipe 


Ex. 
Pipe 


Suet. 
Pipe 


Disch. 
Pipe 


Capacity 
per Min. 


Ins. 


Ins. 








Ins. 


Ins. 


Ins. 


Gallons 


4 


4 


500 


6.25 


1 


Hi 


4 


4 


450 


5 


5 


500 


12.5 


IV2 


2 


6 


6 


1,000 


6 


6 


400 


17.5 


2 


2 


8 


8 


1,800 


7 


6 


400 


23.75 


2 


2« 


10 


10 


2,800 


8 


10 


325 


42.75 


2« 


3 


12 


12 


4,000 


9 


10 


325 


54. 


3 


3« 


14 


14 


5,500 


10 


10 


325 


66.75 


3 


3H 


16 


16 


7,500 


11 ] 


10 


325 


81. 


3H 


4 


18 


18 


9,500 


12 


10 


325 


96. 


3^ 


4 


20 


20 


12,000 


14 


12 


325 


156. 


VA 


6 


24 


24 


18,000 



The capacities given in the above table are maximum and are 
for pumps working under heads not exceeding 20"ft. An efficiency 
of 65 to 75% is guaranteed by the builders on their pumps having 
a discharge of over 6 ins. 



Digiti 



zed by G00gk 



476 



MACHINERY 



Centrifugal Dredging Pumps 

(Worthington Steam Pump Co.) 



No. Pump 
(Diameter 


Diameter 


Cubic Yards Material 
10 to 20 Per Cent. 


per Hour, 
3f Solids 


Approximate 

Horse Power 

Required 

for Each 

10 Feet 


Will Pass 
Solids, 


Discharge 


Suction 






Diameter, 


Opening) 






Inches 






10% 


15% 


20% 


Elevation 




4 


4 


14 


21 


28 


4 


2 


6 


6 


30 


45 


60 


8 


*M 


8 


8 


60 


90 


120 


15 


6 


10 


10 


90 


135 


180 


25 


8 


12 


12 


125 


190 


250 


30 


10 


15 


15 


210 


315 


420 


50 


10 


18 


18 


300 


450 


600 


70 


10 



Priming. — Centrifugal pumps that are placed above the suction 
water level must be primed before starting; that is, all the air 
driven out of the pump and suction pipe and the space filled with 
water. When steam is available either an ejector or syphon could 
fill the pump and suction pipe with water, but when so doing the 
air cock on the pump must be open. 

The peripheral speed in feet per minute necessary to lift water 
to a given height depends on the form of the vanes. If a is a 
straight radial vane, b a straight vane bent backwards, c a curved 
vane its extremity making an angle of 27 degs. with a tangent to 
the impeller, d a curved vane with an angle of 18 degs., and e is a 
vane curved in the reverse direction so that the outer end is radial, 
then 

the peripheral speed in feet per min. for a = 481 \/ h 

the peripheral speed in feet per min. for b = 554 \/7i 

the peripheral speed in feet per min. for c = 610 \/~h 

the peripheral speed in feet per min. for d = 780 y/H 

the peripheral speed in feet per min. for e = 394 y/ h 

where h is the head or lift in feet. As the coefficient varies with 

the shape of the vanes, different speeds are necessary to hold water 

to the same height. To obtain the revolutions of the vanes, divide 

the peripheral speed by the circumference of the circle swept over by 

the vanes (Mech. EngYs Pocket Book, W. Kent). 

Doctor. — On steamers navigating the Mississippi River and 
its tributaries, a combined feed pump and feed water heater called 



JvJ^Vl^ 



AIR PUMP 477 

a "doctor" is installed. This consists of a vertical beam engine 
with crank and flywheel operating four pumps. Two are simple 
lift pumps drawing water from the river and delivering it into the 
heating chambers overhead, while the other two are feed pumps 
taking their supply from the heater and delivering the water to the 
boilers. Each lift and force pump is of sufficient capacity to supply 
the entire battery of boilers, so that one pump of either kind may 
be disconnected for examination or repair without disturbing the 
regularity of the boiler feed supply. 
Air Pump, see page 459. 

Pumps Installed in a Freight Steamer 
For particulars of the steamer Pacific (geared turbine), see 
page 312. 

Pumps 
1 Main air, Vertical twin beam, 14 ins., 28 ins., 18 ins. 

1 Circulating, Centrifugal 42-inch runner, 14 ins. dia. of 

suction, engine 10 inch by 10 inch. 
1 Main feed, Centrifugal, turbine-driven, 37 h. p. 

1 Auxiliary. Centrifugal, turbine-driven, 37 h. p. 

1 Fire and bilge, Duplex horizontal, 12 ins., 8 H ins., 12 ins. 

1 Ballast, 12 ins., 10^ ins., 12 ins. 

1 Trimming, 10 ins., 7 ins., 10 ins. 

1 Sanitary, 7 l /$ ins., 5 ins., 6 , ins. 

1 Fresh water, 7J^ ins., 5 ins., 6 ins. 

1 Evaporator, 4J^ ins., 2% ins., 4 ins. 

1 Engine room bilge, 6 ins., 5% ins., 6 ins. 

2 Fuel oil, 6 ins., 4 ins., 6 ins. 

Installing and Operating Pumps. — Blow out with steam all 
chips and dirt in steam pipe before making final connection to 
pump. 

Never use a smaller pipe on the suction than the list calls for. j 

Avoid right angles in the pipe, where it is possible. 

Where it is practicable, make bends with a large radius and 
use Y's instead of T's. 

Put a foot valve and strainer on the end of the suction pipe. 

Do not place the pump more than 25 ft. above the water. 

Where hot water is pumped, the supply must be above the pump. 

Make all joints in the suction air tight. 

Keep the stuffing boxes well and evenly filled with packing. 

Oil the pump before starting it, and keep the oil wiped off where 
it is not needed. 

In cold weather drain the steam and water cylinders to prevent 
freezing. 

Digitized by VjiOOQ LC 



r 



478 MACHINERY 

For high-speed pumping and on long suction lines, have a vacuum 
chamber near the pump. 

Ordinarily do not run pump (reciprocating) more than 100 ft. 
piston speed per minute. 

For feeding boilers do not run piston (reciprocating pump) 
more than 50 ft. per minute. 

For boiler feeding, a check valve must be placed in the discharge 
pipe near the boiler. 

A pump, which when starting has pressure on its discharge 
valves, will often fail to lift water. This is caused by the accumu- 
lated air in the pump cylinder, which is not dislodged but merely 
compressed by the movement of pump piston or plunger. To 
get rid of this air, place a check valve in discharge near the pump 
and a waste cock between this check valve and the pump. Run the 
pump with the waste cock open until it picks up the water. If 
the pump has a heavy lift, connect a priming pipe (containing 
a good valve) from a supply of water to the suction pipe near the 
pump. A few strokes of the pump with the priming valve and 
waste cock open will enable it to catch its water. 

A single double-acting pump will usually give less trouble on 
heavy lifts than a duplex pump. 

INTERNAL COMBUSTION ENGINES 

Internal combustion engines, commonly called motors, run on 
a variety of fuels, as gasoline (petrol), kerosene, distillate, and 
producer gas. Crude oil can be successfully used only in Diesel 
and semi-Diesel engines. Along the Atlantic Coast engines run on 
gasoline and kerosene, with more running on the former than on the 
latter. On the Pacific Coast distillate is popular and excellent 
results are secured with it. In Europe the fuel is petrol, which is 
another name for gasoline. See Oil. 

Kerosene is generally cheaper than gasoline, although it is not 
so powerful. Engines using kerosene do not start so quickly as 
those on gasoline, and they cannot be controlled as easily. With 
kerosene the engine has one certain speed at which it runs better 
than at any other; consequently this fuel is suitable only for boats 
running for long periods at a constant speed. It is doubtful whether 
an engine using kerosene has any advantages over one using gaso- 
line, when considering the adaptability to changes of speed of the 
engine and freedom of carbonization that is obtained with gasoline, 
even if it costs more. 

Digitized by LiOOQ LC 



GAS ENGINES 479 

Engines running on producer gas have been installed on some 
small commercial craft the builders of which have claimed low 
operating costs. But gas producers take up considerable room, 
and as a whole, liquid fuels are much more popular for marine use. 

Engines operating on gasoline consume on an average about 
one pint per horse power per hour. Kerosene engines require 
about 6% more fuel than gasoline to get the same power. Diesel 
engines have been run on only .54 of a pint of crude oil per horse 
power per hour. 

The limit of size for engines running on gasoline, kerosene, or 
producer gas, where the ignition is electric or hot torch, is about 
500 h. p., while those running on crude oil and operating on the 
Diesel principle have been built up to 4,500 h. p. 

Operation. — Engines operate on the two-cycle, four-cycle and 
Diesel principle. In the former, on the upstroke of the piston 
the air in the cylinder is compressed; then the fuel enters and is 
ignited, thus forcing the piston down and giving the power stroke. 
In the two-cycle engine there is a power stroke at every revolution 
of the crank shaft. 

In the four-cycle the piston draws into the cylinder on the down- 
stroke the explosive mixture of air and oil vapor, which is com- 
pressed on the upstroke and then ignited, the resulting explosion 
driving the piston down and the return upstroke driving out the 
burnt gases. 

Gas or Gasoline Engines 
Two-Cycle 
First revolution — Downstroke: Ignition and expansion power 
stroke 
Lower portion of downstroke: Exhausting 
gases and taking pure air in cylinders for 
cleaning, and air and gas charge. 
Upstroke: Compression of charge. 

Four-Cycle 
First revolution — Downstroke: Suction of air and gas. 
Upstroke: Compression of air and gas. 
Second revolution — Downstroke: Ignition and expansion power 
stroke. 
Upstroke: Exhaust. 

The compression just prior to the explosion varies from 50 to 80 
lb. per square inch (in Diesel engines it is about 750), and the 
pressure of the explosion is from 150 to 300 lb. The temperature 

Digitized by vjOOQ IC 



480 MACHINERY 

in the cylinders ranges from 1 } 900 to 2,000° F., except in Diesel 
engines where it is from 1,000 to 1,100. 

The advantages of high compression are: (1) more power 
obtained from a given size of cylinder as the particles of gas and 
air are forced closer together; their temperature being raised 
by compression, ignition is more rapid and a better explosion is 
secured; (2) gas (fuel) of poorer quality may be used with a greater 
certainty of the charge igniting, for gas whieh will not ignite at 
ordinary temperature and pressure may be made more combustible 
at high and rapid compression; (3) higher thermal efficiency, for 
a high explosive pressure allows a greater range of expansion to 
follow without allowing the pressure to fall unduly low. 

In the Diesel engine the air in the cylinder is first compressed 
to a pressure of 450 to 600 lb. per square inch, and the liquid fuel 
is forced directly into the cylinder at a pressure of about 750 lb. 
The he$t due to the high compression (depending on the temper- 
ature required to ignite the fuel) ignites the fuel, thus forcing the 
piston down and giving the power stroke. The fuel is pumped 
under pressure into the cylinder in an extremely finely divided 
state by a stream of air from 150 to 300 lb. higher than that in 
the cylinder. This mingling with the highly heated air charge 
in the cylinder immediately ignites the fuel. 

In the paragraphs immediately following are data on engines 
where the mixture in the cylinders is ignited by an electric spark, 
on page 492 Hot Bulb, and on page 495 Diesel. 

Engines (electric ignition) may be divided into three classes, 
viz., high speed, for racing boats and fast runabouts, medium 
speed, for cruisers, and slow speed heavy duty, for towboats, light- 
ers, and small passenger vessels. Below is a table of representative 
types and on page 317 is a table of motor boats. 

Horse Power Formulae for Two- and Four-Cycle Engines. 
Formula. 

Let P = mean effective pressure, in slow speed engines about 80 lb. 
A = area of piston in square inches 

S = piston speed in feet per minute (obtained by multiplying 
the revolutions per minute by two times the stroke in 
inches and dividing by 12) 
N — number of cylinders 
E =* mechanical efficiency taken at .75 
C — 2.5 for two-cycle engines 
4.0 for four-cycle engines 

R - _ P XA XS XN XE 
n * p ' ~ 33,000 X C 

Digitized by VjOOQ IC 



ELECTRIC IGNITION 481 

Internal Combustion Engines (Electric Ignition) 







Num- 






Revo- 


Length 
from Fly- 




Class of Motors 


Horse 
Power 


ber of 
Cylin- 
ders 


Bore 


Stroke 


lutions 

per 
Minute 


wheel to 
Coupling 
for Propel- 
ler Shaft 


Weight 
in Lb. 


High Speed 


65 


4 


5H 


6 


1,200 


5' 4' 


950 


(Van Blerck Mo- 


00 


4 


5H 


6 


1,600 


5' 4* 


940 


tor Co.) Special 


100 


6 


5 l A 


6 


1,200 


6' 6* 


1,120 




135 


8 


5^ 
5*4 


6 


1,200 


V 8* 


1,450 


Special 


180 


8 


6 


1,600 


V 8' 


1,425 


Medium Speed 


3-5 


1 


Wa. 


5 


550 


2' 0* 


325 


(Frisbie Motor . 


5-7 


1 


6 


6 


450 


2' 3* 


500 


Co., Middletowat 


6-10 


2 


*H 


5 


550 


2' 6* 


430 


Conn.) 


10-14 


2 


6 


6 


450 


2' 9H* 


700 




12-18 


3 


*U 


5 


600 


3' 2W 


650 




18-25 


3 


6 


6 


500 


3' 7H" 


1,050 




25-30 


4 


/*« 


5 


800 


3' 6* 


725 




30-40 


4 


6 


550 


4' 2' 


1,200 




-35-50 


6 


43* 


5 


600 


4' 6H" 


985 




5£-75 


6 


6 


6 


550 


5' 5*2" 


1,600 


Heavy Duty Wol- 
verine 


12-14 
18-21 


2 
3 




7 
7 


400 
400 


5' 0* 
5' 10* 


1,550 
2,470 




27 


3 


7H 


9 


350 


V 6* 


3,823 




36 


3 


&A 


9 


350 


V 6' 


3,925 




50 


3 


9H 


12 


300 


9' 0* 


6,538 




75 


3 


11 


12 


300 


9' 0* 


7,025 




100 


3 


12K 


14 


280 


10' 3* 


10,260 



The horse powers in the above are based on using gasoline. 

Another Formula. 

Let d = diameter of cylinder 
I — length of stroke 
r = revolutions per minute 
N =» number of cylinders 



Then h. p. for a two-cycle engine 



# XI Xr XN 
13,500 



d 8 X I X t X N 
Then h. p. for a four-cycle engine = TSOO or h. p. = 

this being based on a piston speed of 100 ft. per minute. 



d? X N 
2.5 



1017 Formula of the American Power Boat Association. 
A - area of one piston in square inches 
JV = number of working pistons 
S = length of stroke in inches 

B = maximum number of revolutions obtainable under racing 
conditions 

Digitized by VjiOO* 



ile 



482 MACHINERY 

C « for 4-cycle gasoline engines 12,000 

2-cycle gasoline engines 9,000 

4-cycle Diesel engines 9,600 

2-cycle Diesel engines 6,000 

ti • j u A u A X N X S X R 
For cruisers and open boats h. p. =» pj 

A X N X S 

displacement racers and hydroplanes, h. p. = 

y 

Carburetors and Vaporizers. — The former is for gasoline and the 
latter for kerosene, but both have the same object, viz., to mix 
the fuel with the proper amount of air to form a suitable explosive 
mixture. There are a variety of carburetors on the market de- 
signed for high and low speed engines and for heavy and light fuels. 
The carburetor selected should be adapted to the speed of the 
engine and to the fuel. 

In one type for high speed gasoline engines the fuel is controlled 
by a needle valve working automatically with the throttle. In 
another there is a jacket around the body of the carburetor through 
which the exhaust gases from the cylinders pass, thus heating the 
gasoline and vaporizing it. In another make, instead of the ex- 
haust gases, the hot water from the cylinder jackets is- circulated 
around it. 

Before installing be sure that the gasoline tank and piping are 
clean and contain no particles of dirt or scale. Connect the car- 
buretor to the intake pipe so it is about 6 ins. below the bottom 
of the gasoline tank; for the best results it should be as close to 
the cylinder as possible, and in case of multicylinder engines equi- 
distant from each if practicable. The carburetor should be adjusted 
to the normal running temperature of the motor. 

The ordinary gasoline carburetor will not vaporize kerosene 
satisfactorily, hence a special vaporizer is required. The kerosene 
and air pass through a nest of heated copper tubes and by so doing 
a vaporized mixture is secured. Just before the mixture enters 
the cylinders a few drops of water are mixed with it, the water, 
being drawn with the mixture into the cylinders, forms steam at the 
time of combustion, thus permitting high compression without 
preignition. To heat the copper tubes it is necessary to start the 
engine on gasoline, and after it is warmed up to shut off the gaso- 
line and turn on the kerosene. 

Starting. — Engines of 50 h. p. and over are started by compressed 

Digitized by vjOOQ LC 



REVERSE GEARS 



483 



air or by an electric motor. In the former, when the engine is 
running it drives a small air compressor that compresses air which 
is stored in a tank. From this tank pipes lead to the different 
cylinders. In the pipes are valves for controlling the air supply. 
In the case of electric starting, the electric motor gets its energy 
from a storage battery. The motor turns by means of a chain 
the crank shaft of the engine, and when the latter is running the 
motor is either stopped entirely or reversed, that is, turned into 
a generator, and as such recharges the storage battery. 




Figure 82. — Reverse Gear. 



Reverse Gears. — In motor boats the motors run in one direction, 
a boat being made to go ahead or astern by changing the direction 
of rotation of the propeller shaft irrespective to that of the motor. 
This is accomplished by a lever controlling gears housed in a casing 
directly aft of the engine. The gearing is designed so that for full 
speed ahead the lever is thrown way forward, for astern way aft, 
and when neutral or perpendicular the boat is not under headway 
although the engine may be running. For small launches, some- 
times propellers with reversible blades are installed. 

Fig. 82 is of a reverse gear built by Snow & Petrelli, New Haven, 
Conn. The engine sleeve carries one of the central gears, into 
which meshes a short pinion, which meshes with a long pinion, that 
meshes with another central gear that is attached to the propeller 
sleeve. Whichever way the engine runs the propeller will be 
turned in the opposite direction. With this gear four revolutions 



ile 



484 MACHINERY 

of the engine make three revolutions of the propeller in the reverse 
direction. 

Lubricating Systems. — Nearly every engine builder has a different 
system. Some builders of two-cycle engines claim to have secured 
satisfactory cylinder, connecting rod, and crank bearing lubrication 
by mixing with the gasoline lubricating oil. Other builders use the 
splash system, which consists of partly filling the bottom of the crank 
case with oil, and as the cranks revolve, the oil is splashed over the 
bearings and connecting rods. Care must be taken that the dippers 
on the connecting rods barely dip into the oil, for if there is too 
much oil thrown, the igniters or the spark plugs will become foul. 

Most builders have adopted the force feed, the oil being dis- 
tributed through pipes to the bearings and other parts by a pump, 
driven from the engine shaft. The cylinder gets oil at about the 
center, the oil entering at the level of the wrist pin when the piston 
is down, and bpreading over the cylinder wall through grooves 
in the piston. Some of the oil enters the hollow wrist pin, to which 
the end of the connecting rott is fastened, and lubricates it. The 
gears in the reversing gear in many instances run in a heavy oil, 
while the bearings outside of the engine are fitted with grease cups. 

The consumption of oil for the bearings and cylinders should 
not exceed one and a half gallons per 1,000 b. h. p. A 16 h. p. en- 
gine has been run 820 miles on four gallons of oil, and a 32 h. p. 
1,300 miles on ten gallons. (See section on Oil.) 

Cooling water required for the cylinders is approximately 8 to 
10 gallons per b. h. p. The cylinders should be hot, for if they 
are kept too cool there is a loss of efficiency and power. The water 
is forced through the jackets by a centrifugal pump driven by 
the engine, although sometimes a plunger pump is used. 

Valves. — The valves controlling the entrance of the explosive 
charge into the cylinder in two-cycle engines have two or three ports. 
In the former, on the upstroke of the piston the charge enters 
the crank case through a check valve which closes on the down- 
stroke. In the three-port, the check valve is not required. 

In four-cycle engines the inlet and exhaust valves are usually 
operated in either of two ways: (1) the exhaust valve is cam oper- 
ated with the suction of the piston operating the inlet valve on the 
second or charging stroke (often, known as the automatic or suction 
inlet) ; or (2) the inlet and exhaust valves are mechanically operated. 
The latter arrangement is adapted for high speed engines, while 
the former (1) is for slow speed heavy duty. 



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486 MACHINERY 

When the valves are on the opposite sides of the cylinder, the 
cylinder is known as the T type/ and when they are both on the 
same side, the L; in the T two cam shafts are required while in the 
L only one. Another type has the valves inverted and seated 
directly on the top of the cylinder, but in this arrangement either 
an overhead cam shaft or long valve lifters are required. 

It is most important that the valves be correctly timed, the 
exhaust valve opening soon enough that the gases will quickly pass 
out and will not foul the plugs, the exhaust valve closing before 
the inlet valve is opened. 

Ignition. — The explosive charge may be ignited either by a hot 
bulb or an electric spark. In the former a bulb in the cylinder head 
is heated by a torch (see Hot Bulb Engines) requiring from 4 to 5 
minutes before the proper temperature is reached. Electric ignition 
is preferable to torch for pleasure boats. An idea of the number 
of sparks required can be obtained from the fact that in a four- 
cycle engine running at 800 r. p. m. about 400 sparks are needed 
per minute for each cylinder. 

Make and Break Ignition. — Electric ignition is either of the 
make and break (low tension) system or the jump spark (high ten- 
sion). In the former a spark is produced by the breaking of an 
electric circuit the contact points of which are in the combustion 
chamber of the cylinder. There is required a battery or a magneto 
for generating the current, a coil, and an igniter (one for each 
cylinder). (See Fig. 83.) 

The current is led to a coil consisting of a core of soft iron wires 
around which are wound several layers of heavy insulated copper 
wire. The current, after passing through the coil, goes to the 
terminals of the igniter which consists of a fixed and a movable 
electrode, the latter being operated by the rise and fall of a rod 
the end of which bears on a shaft that is driven by the main shaft 
of the engine by gears. The contact points of the igniter are often 
tipped with platinum-iridium, which insures long wear and clean 
points. 

One of the advantages of the make and break system is that 
it is not easily affected by dampness and is consequently largely 
adopted for engines installed in open boats. Its disadvantages 
are that there are moving parts within the cylinder, and it is only 
suitable for slow speed engines. 

Jump Spark or High Tension System. — Here (see Fig. 84) the cur- 
rent is transformed from a primary or low tension to a high tension 

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SPARK COILS 487 

by a spark coil, and then as a high tension current it is led to the spark 
plug in the top of the cylinder, the current jumping across the gap 
between the points of the plug and by so doing creating a spark. 
It is evident that the spark must be controlled, otherwise there 
would be one continuous spark between the points of the plug. 
The controlling of the spark is accomplished either by a timer or 
a distributor. 

Spark coils for high tension ignition are different from those 
of low tension ignition in that they are covered with another winding 
of fine insulated copper wire; that is, they consist of a core of soft 
iron wire around which is wound a few layers of coarse copper 
wire called the primary coil, on top of which is wound a great many 
layers of fine insulated copper wire called the secondary coil but not 
connected with the primary. When a low voltage current is broken 
in the primary coil, a high voltage one is induced in the secondary, 
and this goes to the spark plugs. 

A coil is necessary for each spark plug, hence for each cylinder 
when a timer is used. The coils can either all be placed in a com- 
mon box or a combined coil and plug made which is screwed into 
the top of the cylinder just like an ordinary spark plug. With a 
distributor (see Timers and Distributors) only a single coil is re- 
quired. 

High tension .systems are particularly adapted for high speed 
engines, and there are several types on the market. For instance, 
the dual, where the cylinders have two plugs, one when running 
on the batteries and the other when on the magneto. 

Timers and Distributors. — The time of ignition can be controlled 
in the jump spark system by a timer driven from the engine shaft, 
which completes the primary circuit between the battery or magneto 
and the spark coil at the proper instant at which the ignition of 
the charge in the cylinder must take place. If a timer is used without 
any other device, then a separate coil is required for each cylinder. 

A distributor is a modification of a timer enabling a single coil 
to ignite a multicylinder engine. The distributor gives the proper 
distribution of the secondary current of the induction coil to each 
cylinder at the proper time. 

Thus a timer works on the primary or low tension current, and 
with a timer, coils are required for each cylinder, while a distributor 
works on a secondary or high tension current, requiring only one 
coil for a multicylinder engine. 

A system which has proved satisfactory is the Kent (A. Kent 

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TIMING THE IGNITION 489 

Mfg. Co., Philadelphia, Pa.), in which, in addition to the usual 
battery or magneto for generating the current, there is a device called 
a unisparker, consisting of a mechanical contact maker, a high tension 
distributor, and a non-vibrating spark coil. The unisparker is 
driven from the engine, giving one spark per revolution, the im- 
portant feature in its construction being that it produces a spark 
of constant strength irrespective of the speed of the engine, and that 
the battery circuit is never closed except at the instant of the spark. 
Thus the engine can never stop so as to leave the ignition circuit 
closed if the switch is accidentally left on. As a result of the small 
current consumed, a set of ordinary dry cells will last several weeks. 

Timing the Ignition. — The timing of the ignition of a single- 
cylinder jump spark engine is outlined below, but the same pro- 
cedure is followed irrespective of the number of cylinders. 

Open the priming cup or take off one of the spark plugs and put 
a piece of stiff wire in the cylinder so that one end rests on the top 
of the piston. Then by noting the rise and fall of the wire as the 
crank shaft is turned, the position of the piston at any part of the 
stroke can be determined. (1) Turn the engine so that the piston 
is on the top of the compression stroke. (2) Turn the flywheel 
about 10° more, always in the direction in which the engine is to 
run, so that the piston is about 10° past the high center point, and 
then put the timer in place with the contact points of the timer 
together forming a circuit. Now wire the timer to the spark coil 
(see section on Electricity). 

Magnetos are small generators for furnishing the current for 
ignition purposes and are driven from the main engine by belts, 
gears, or by direct contact with the flywheel. There are two 
types, viz., low and high tension. The low is for either jump 
spark or make and break ignition, while the high is only for jump 
spark. A low tension magneto generates a primary current, hence 
a coil is required to increase it to a higher voltage. By having the 
proper ratio between the revolutions of the shafts of the low tension 
magneto and of the engine, as say four to one, the engine may be 
started without a battery. A low tension magneto in a jump 
spark circuit requires a separate spark coil for each cylinder, but 
when in a make and break only one coil is needed. 

High tension magnetos are only for jump spark ignition and 
differ radically from the low as neither a spark coil nor a timer is 
necessary. In the high tension there are two windings, a high 
and a low, and a circuit breaker that breaks the circuit in the high 

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490 MACHINERY 

tension winding. This is located at the end of the magneto shaft 
and can be rocked backward and forward, thus serving to advance 
or retard the spark. The function of the circuit breaker is to 
interrupt the primary current, thereby causing an induced high 
tension current in the secondary winding which goes direct from the 
distributor binding post to the spark plug. No coil or timer is 
necessary, as these magnetos have a complete ignition system 
within themselves, having their own windings and a circuit breaker 
that takes the place of a timer. 

The advantage of a high tension magneto is that a hot spark 
is generated and as there is only one circuit breaker for the primary 
circuit which is alike for all cylinders, more accurate timing is 
secured than by separate vibrating coils. These magnetos are 
gear driven from the engine, and as they are more sensitive than 
the low they must be carefully protected from the weather. On 
small engines that can be cranked 50 or more revolutions a minute, 
the engines can often be started direct on high tension magnetos, 
no batteries being required, but for larger sizes batteries are gen- 
erally necessary. 

Spark plugs are for igniting the explosive mixture in the com- 
bustion chamber. Preferably the spark between the points should 
be in the form of a flat sheet rather than a ball, for a spark with an 
extensive surface or area will ignite a greater number of mixture 
particles in a given time than will a thin threadlike spark. The 
plug should be located near the intake valve in such a manner that 
it will be surrounded by the fresh gas that enters during the inlet 
stroke. If on the exhaust side, dead gas is liable to collect around 
the points and cause missing. 

If the engine misses, examine the spark plugs. Clean off the 
mica or porcelain and see that the points are about & of an inch 
apart. To test the plug, unscrew it and lay it on the cylinder 
head or other part of the engine where there is no paint. Attach 
a wire to the plug, but only let the outside or shell of the plug rest 
on the cy Under. Turn the flywheel until contact is made at the 
timer. If the vibrator does not buzz, adjust the screw until it works 
properly, then notice the size of the spark at the points of the plug. 
If no spark occurs take the plug apart and clean it. Then if, on 
reassembling, again no spark occurs, look for bad vibrator points 
or exhausted batteries, broken wire, or loose connections. Too 
much or too poor cylinder oil, and too rich a mixture, will cause 
the plug to foul and become sooted. 

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BATTERIES 



491 



Batteries. — See section on Electricity. 

Motor Trouble. — The following applies to two- and four-cycle 
electric ignited gasoline engines. If after cranking the engine four 
or five times it does not start, see that the fuel is turned on, that 
the electric switch is thrown in, and that there is nothing caught in 
the shafting. If the engine starts, then slows down, and finally 
stops, the fuel supply is chocked or the batteries have given out. 

Should the compression be weak, see if any of the spark plugs are 
loose, or perhaps the valves leak, or there may be a broken piston 
ring. If the valves leak they should be reground. This is done by 
taking out the valve, putting a grinding compound on the seat, 
replacing the valve and turning it to the right and left until a clean 
smooth surface is on the valve face. Care should be taken in grind- 
ing that none of the compound gets into the cylinder; if it does it 
should be removed. 

If the engine will not start, begin a systematic search for trouble, 
beginning with the carburetor and then going over the ignition sys- 
tem. 



Part 
Carburetor 



Trouble 



Water in gasoline or in carburetor. 

Air valve or the needle valve is out of adjustment. 
Ignition System Spark plugs dirty or short circuited (see Spark 
Plugs). 

Broken cable or poor connection at the terminals. 

Vibrator out of adjustment or points burned. 

Weak batteries. 

Timer dirty. 

See if magneto is revolving in the direction of 
rotation stamped on the end. 

Open the circuit breaker and see that it is not 
flooded with oil and there is no oil on the con- 
tact points. 

Dirty spark plugs. 

Backfires in carburetor, too lean a mixture. 

Valves leak. 

Batteries weak. 

Wrong spark plug gap. 

Connections loose. 

Engine not bolted firmly to its foundation. 

Piston ring broken. 

Shaft bearing loose. 

Connecting rod loose. 

Water circulation stopped. See if sea cock is 
open, pump working, and the pipes not 
clogged up. 

Cylinder getting no oil. 



Engine runs but 
misses 



Engine pounds 



Cylinders get 
very hot 



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492 MACHINERY 

If the engine begins to backfire, this indicates that the gasoline 
tank is empty or the supply pipe is stopped up. Should the engine 
stop suddenly this may be caused by the electric circuit being 
accidentally broken or the supply of fuel stopped. 

Abstracts from Motor Boats, by Chas. H. Hughes, perm. Am. Tech. Soc., Chi- 
cago. 

Hot Bulb Engines 

In hot bulb (sometimes called / semi-Diesel) engines no electric 
ignition is required, there being instead a bulb which is first heated 
by a torch. After the engine has started the torch may be put 
out, as the heat produced by the explosion of the fuel in the cylinder 
is sufficient to keep the bulb hot. The compression is from 85 to 
215 lb. per square inch, and the pressure from the explosion 260 to 
350 lb. 

Engines of this type have proved very satisfactory for medium size 
seagoing vessels and have been installed in many sailing vessels 
(see page 318). They are reliable, their fuel consumption is low and 
a cheap grade can be used. They are built in sizes up to about 
500 h.p. A well-known make is the Bolinder (built by J. and C. G. 
Bolinder, New York) which is of the two-cycle type with a working 
pressure of about one-third that of a Diesel engine. Complete com- 
bustion is obtained by mixing the fuel with air before injecting it 
into the cylinder. For this purpose a special nozzle has been con- 
structed in which the fuel oil is automatically mixed with air. No 
water injection in the cylinders is necessary at normal load or 10% 
overload. The engine can run on cheap and heavy oils. 

All Bolinder engines having more than one cylinder are started 
by compressed air. The ignition balls are heated (from 7 to 15 
minutes being necessary, depending on the size of the engine), and 
when ready to start, open the cylinder cocks to avoid compression 
in the cylinders and turn the flywheel until the mark on it is on top, 
in which position the piston has just commenced its downward 
stroke. Next close the cylinder cocks. The stop valve on the air 
receiver is now opened and the hand wheel of the starting valve is 
opened 2 or 3 turns, after which by means of a hand lever the valve 
is opened for a moment, allowing air to enter the cylinder, and is 
quickly closed, the engine readily starting. 

This engine is also direct reversible, the reversing being accom- 
plished as follows: 

1. The clutch is thrown out by means of a hand lever. 

2. The reversing lever is pulled aft (for going astern). This 

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REVERSIBLE ENGINES 



493 



movement causes the engine to slow down at once; a charge of oil 
if. automatically injected at the appropriate stage of the cycle and 
the movement of the piston is immediately reversed. 

3. The reversing lever is returned to its central position. 

4. The clutch is thrown in again. 

The reversing is done by two hand levers. To change from astern 
to ahead the procedure is exactly the same except that the reversing 
lever is thrown over in the opposite direction. 




Figure 85.— Hot Bulb Engine (Bolinder Co., New York).] 
The following table gives particulars of the engines. 

Bounder's 4-Cylinder Direct Reversible Engines 



Brake horse power 


80 

425 

8,700 

42 


100 

385 

12,600 

45 


160 

325 

22,800 

55 


240 

275 

33,600 

63 


320 

225 

44,400 

75 


500 


Revolutions per minute 

Weight in pounds (approx.).. . 

Diameter of propeller (3 blades) 

inches 


160 
89,600 

106 







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Another hot bulb engine is the two-cycle Skandia built by the 
Skandia Motor Works, Lysekil, Sweden. One of the features of 
this engine is that it works without water injection. When running 
without load or with a small load many engines require no water 
injection owing to the fact that only a small quantity of heat is 
imparted to the walls of the combustion chamber. If the load is 
increased, the heat will rise to a high degree, especially in case of 
overload, so that the walls, if not water cooled, become red hot, 
thereby causing advance ignition. Apart from the space required 
by water tanks, the water injection has an injurious influence upon 
the life of an engine. In a Skandia, the water-cooled cylinder cover 
makes water injection unnecessary. 

In direct connection with the governor is the fuel pump which is 
worked through the medium of a cam. By means of an adjusting 
screw, combined with the governor, the fuel feed may be regulated 
instantaneously while the engine is running, and after the stroke 
of the pump has been adjusted to suit the load of the engine the 
engine will run continuously with the same number of revolutions. 
When the fuel supply is properly adjusted the exhaust gases are 
smokeless. 

All engines of 25 h.p. and over are supplied with a starting device 
consisting of a starting valve and steel air tank connected by copper 
piping. The engine can be started by a pull on the handle of the 
starting valve. 

Skandia engines are built in three types: (1) direct reversible 
like a steam engine, which is secured by means of • compressed air; 
(2) with a reversing gear; and (3) with a reversible propeller. 



Skandia Oil Engines (Direct Reversible) 









Cons, of Fuel 


Approx- 


Number of 


Brake 


Revolutions 


in Lb. per 
B.H.P. Hour 


imate 


Cylinders 


Horse Power 


per Minute 


Gross Weight, 








at Full Load 


Pounds 


4 


90 


375 


6.6 


14,960 


4 


120 


375 


6.38 


15,906 


4 


140 


325 


6.38 


18,480 


4 


200 


300 


6.38 


20,570 


4 


240 


300 


6.27 


29,700 


4 


385 


250 


6.16 


56,100 



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DIESEL ENGINES 495 

Diesel Engines 

Engines working on the Diesel principle do not require an ignition 
system, as the fuel is ignited by being forced into cylinders of com- 
pressed air. The pressure in the cylinders is from 400 to 600 lb. 
per square inch (depending on the fuel) and as the fuel must be 
injected at a higher pressure, say 750 lb., an air compressor is 
required. These engines are started and reversed in many instances 
by compressed air, and the space occupied by them is about 80% of 
a steam engine and boiler of the same power. 

Diesel engines have been installed in many freight vessels (see 
page 316), and on account of their low operating costs (see page 335) 
due to cheap fuel and the small number of men required, they have 
proved very satisfactory on certain routes. Submarines are driven 
by them when running on the surface. 

Care must be exercised in the selection of fuel, because one which 
is suitable for one make of engine may not be for another having a 
different compression or system of atomization. It is an object to 
use the cheapest fuel possible but in a general way Diesel engines 
cannot use crude oils. The fuels which they do require are easily 
obtainable and cost very little more than crude oil. Most Diesel 
engines are guaranteed to run. on crude oil of a certain gravity, but 
this gravity is so high that there are few crude oils that will comply 
with it. When an engine runs well on an oil of a given viscosity, it 
is advisable to get oil as near this viscosity as possible, otherwise the 
entire adjustment of the injection valves must be altered. How- 
ever, a heater may be installed utilizing the warm gases from the 
exhaust for heating the oil. 

A fair average consumption in a Diesel engine on the basis of 
brake horse power per hour when using fuel with a heating capacity 
of 18,500 B. t. u. per pound can be taken as .40 lb. per horse power 
hour for large engines and .46 for small. On this basis, considering 
that oil weighs 7.5 lb. per gallon, the fuel consumption per 100 b. 
h. p. hours would be about 6 gallons. 

k The table on page 496 gives a comparison of Diesel engines, 
ordinary reciprocating marine engines, and geared turbines. Al- 
lowance has been made for the difference in tonnage measurement 
and deadweight capacity which the systems involve. The vessel 
chosen is 400 ft. long between perpendiculars, 52 ft. beam, 29 ft. 
9 ins. deep, and 26 ft. 1 in. draft. Total deadweight carrying capac- 
ity in tons, 8,640 (steam), 8,775 (Diesel), 8,805 (geared turbines). 
Speed 10 ^ knots, radius of action 3,500 miles, fuel consumption 1 .6 



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MACHINERY 



lb. per i. h. p. per hour (reciprocating), 1 .2 lb. per i. h. p. per hour 
(turbine),. .61 lb. per i. h. p. per hour (Diesel). 





' Oil Engine 


Steam Engine 


Geared Turbine 


Capital Invested 


$381,000 


$308,000 


$351,000 


• 


Per 
Voyage 


Per 
Month 


Per 
Voyage 


Per 
Month 


Per 
Voyage 


Per 

Month 






$2,390 

1,700 
537 

537 


$2,170 
3,590 


$1,800 

2,666 
488 

488 


$1,738 
3,590 


$2,050 


Fuel (oil at $9.77, coal at 

$3.66) 

Wages and provisions 

Wear and tear 


$1,756 


' 1,950 
439 


Deck and engine room 




488 


Port charges, at $1 .22 per 
ton 


3,680 










$5,436 
87,000 
62.000 


$5,164 


$5,760 
92.200 
57,300 


$4,776 


$5,328 
85,300 
59,200 


$4,927 


12 months 










$149,000 
19,000 
2,440 




$149,500 
15,400 
2,440 




$144,500 
17,550 
2,440 












Freight-earning cargo car- 
ried, tons 


$170,440 
16 X 8,530 


= 136.480 


$167,340 
16 X 7,880 


- 126.080 


$164,490 
16 X 7,910 


= 126.560 












170,440:00 

136,480.00 

$1.25 per ton 


167,340.00 

126,080.00 

$1.33 per ton 


164.490.00 

126,560.00 

$1.30 per ton 



In general, for moderate speed ships which would be driven by 
a single reciprocating engine, a Diesel engine ship is more costly as 
the machinery is more expensive and the hull also, on account of 
the twin screws, oiltight work, etc., but the space occupied by pro- 
pelling machinery is less and the weight is less, so that there is a 
gain in cargo-carrying capacity and weight. See Costs. At the 
present state of development, Diesel engines are not suitable for 
high-powered vessels from engineering rather than economic reasons. 

General Features. — For a given horse power the cylinder of a 
Diesel engine is J to i the diameter of a steam cylinder, while 
the rods and bearings are about the same size as in a steam engine 
of the same power. The pistons fit the cylinders very closely and 

are usually j^-t of an inch smaller in diameter at the top than at 



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TWO-CYCLE ENGINE 



497 



the bottom, to allow for the expansion due to heat. Six to eight 
rings are fitted haying lapped joints, so that there is no leakage past 
the piston. 

Diesel engines are either two- or four-cycle. In the two-cycle 
engine there is one working or power stroke with every revolution. 
This type of engine has a scavenger pump operated directly from the 
main engine, or scavenger pistons which are extensions of the power 
pistons that furnish the air required for clearing the working cylinder 
of its burnt gases and for filling it with fresh air which is then com- 
pressed on the return of the piston. When the exhaust valves are 
open, air from the scavenger pump is admitted through mechanically 




Figure 86.— End Elevation— Werkspoor Diesel Engine. 

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498 MACHINERY 

operated valves at the piston end of the cylinder, and sweeps before 
it the products of combustion, leaving the cylinder filled with fresh 
air which is then compressed on the return stroke of the piston. 
The two-cycle engine is more complicated than the four, and has in 
some cases 10% higher fuel consumption. However, it has the ad- 
vantage of saving considerably in weight. 

In the four-cycle type, on the down or intake stroke the air is ad- 
mitted through mechanically controlled air inlet valves. On the 
up or return stroke this air is compressed to 400 to 600 lb. per square 
inch, and thereby becomes heated to a temperature of around 
1,000° F. A few degrees before the completion of the compression 
stroke, the liquid fuel is injected into the engine cylinder through the 
oil injection valves and atomizers by means of highly compressed 
injection air. furnished by an independent high pressure compressor. 
This high-pressure air atomizes the oil, breaking it up into a mist 
which on coming in contact with the hot air in the engine cylinder 
is burned and gasified. The gases force the piston down on the third 
or working stroke, expanding gradually, much as steam expands in a 
cylinder after being cut off. On the fourth stroke the burned gases 
are expelled through the discharge or outlet valve into the exhaust 
pipe. The piston sweeps all the gases before it and acts as an effi- 
cient scavenger. The fuel inlet valve in the four-cycle engine is 
built very heavy and as it operates against high pressures it 
has a small movement and remains open from about % of the stroke 
to the minimum cut-off. 

Below are cycles of Diesel engines in a tabular form. 

Two-Cycle 

First Revolution Downstroke Injection of charge and ignition 

by heated air. 
Lower portion of Exhausting gases and taking in 
downstroke pure air for cleaning cylinders. 

Upstroke Compression of air to 1,000° F. 

Four-Cycle 

First Revolution Downstroke Suction of pure air. 

Upstroke Compression to 1,000° F. 

Second Revolution Downstroke Injection of fuel charge, ignition 

by contact with heated air, 
expansion, power stroke. 
Upstroke Exhaust of gases. 

The fuel to the injection valves is usually pumped by a twin 

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INJECTION VALVE 499 

plunger, one plunger doing most of the work and discharging the 
excess through an escape valve back into the suction. The second 
plunger is somewhat smaller and accurately measures the fuel forced 
through the injection valve. On the largest engines these plungers 
are about % to J^ inch in diameter with a small stroke. 

The fuel is atomized by air pressure varying from 600 to 1,200 lb. 
per square inch, according to the make of engine and the fuel. This 
pressure is obtained by a three- or four-stage compressor sometimes 
attached to the main engine, or to an auxiliary engine, and in some 
cases to both. The air from the compressor is stored in steel bottles 
for starting, the bottles having sufficient capacity to turn over the 
engine for about 10 minutes. 

Injection Valve. — This valve may be raised by cams and returned 
to its seat by powerful springs. Various devices have been resorted 
to in order to minimize friction in the stuffing box. Some com- 
panies use an oil lantern in the middle of the stuffing box; others 
ehminate the stuffing box entirely, having instead a stem about 1}^ 
ins. in diameter and 18 ins. long, fitting closely in a sleeve with oil 
grooves instead of packing. The timing of the injection valve, its 
control by the governor, and the timing of the fuel pumps are the 
most delicate adjustments on Diesel engines. 

Timing of Valves. — For the air inlet and exhaust valves the only 
adjustment actually necessary is to compensate for the wear of 
the valves, and this is done by lengthening the valve stems by 
sleeves. 

Suction valves open about 5° below top center and close on the 
bottom center. Exhaust valves open 10° or 12° below the bottom 
center and close near the top center. All valves are closed during 
compression, expansion, and ignition, except the fuel inlet which 
has a lead of 5° to 10° depending on the speed of the engine, the fuel, 
and the type of injection valve. 

Operating Notes. — To start a Diesel engine the air valve to the 
compressed air supply is opened, and after the engine has made a 
few revolutions the governor lever is moved and the injection valves 
begin to act. It is then run slowly until warmed up, as one of the 
greatest troubles with Diesel engines is the cracking of the cylinders 
owing to the constant changes of temperature. 

During this period a round of the engine should be made to inspect 
the action of the valves, try the pet cocks, examine jacket water 
for temperature, and otherwise make sure that the engine is running 
satisfactorily. The engine should run for about 20 minutes at less 



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MACHINERY 




Figure 87a. — Section of motor ship, 40J.5ft. between perpendiculars; displace- 
ment at 26 ft. draft 12,100 tons; 2, 6-cylinder Burmeister & Wain engines, 24.8 in. 
diameter by 37.75 in. stroke, 130 r. p. m., each developing 1550 h. p. (Fig. from 
Int. Mar. Eng'g, New York.) 

than full speed, but if necessary can be brought up to full speed in 
4 or 5 minutes, but it should not be unless means are provided for 
circulating hot water through the engine jackets. 

Engines which have failed on certain kinds of oil have run well 
by raising the pressure of the atomizing air, or by preheating the 
oil, or in other ways improving the atomization. If an engine 
smokes and shows carbon, this may be caused by one of the following 



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TYPES 501 

(1) The fuel is not being atomized. 

(2) The compression is not high enough. 

(3) There is an excess of fuel. 

If the fuel does not atomize it may be because the viscosity is 
too high. In some cases this can be remedied by preheating the 
fuel or increasing the amount and pressure of the air for atomizing, 
but some of the heavier residual fuel oils are so viscous and have 
such surface tension that it is impossible to atomize them into the 
fine mist necessary for clean combustion. If the engine has not 
sufficient compression use a ligher fuel that is more easily ignited. 

Types. — Tables 1 and 2 are of engines built by the New London 
Shipbuilding Co., which are of the two-cycle type. Table 1 gives 
data on engines for Navy use and for high speed yachts where min- 
imum weight is required, which runs from 45 to 50 lb. per h. p. 
depending on the size. This weight includes all auxiliary machinery 
and apparatus as water and oil pumps, fuel pumps, air pumps, 
coolers and filters, as well as the entire reversing apparatus with 
compressed air receivers. Engines of the same over-all dimensions 
can be furnished of heavier weight, viz. 60 to 65 lb. per h. p. for 
medium duty, while heavy weight slow speed engines averaging 97 
lb. are given in Table 2. 

The above engines are of the single acting two-cycle type. On 
the upstroke of the piston pure air is compressed in the working 
cylinder to a high pressure and thereby becomes heated to a tempera- 
ture above the flash point of the fuel oil. Shortly before the end of 
the upstroke, a spray valve opens and fuel oil is delivered, for a short 
time at the beginning of the downstroke, into the cylinder, and begins 
to burn. This downstroke is the real working stroke. At the end 
of this stroke the burned gases are exhausted, and the cylinders are 
scavenged and filled with pure air which is then compressed and 
the cycle repeated. 

Another engine operating on the Diesel principle and of the 
two-cycle type is the Southwark-Harris valveless engine. The cycle 
of operations is as follows: (1) the fuel pump places a small quan- 
tity of crude or fuel oil in the atomizer at a certain time in the revo- 
lution of the engine and leaves it there; (2) the scavenging pump 
blows out the previous charge through the exhaust and leaves a 
charge of pure air in the cylinder when the piston is at the end of 
its outward stroke; (3) the piston then compresses the charge of 
pure air into such a small space that it becomes very hot; and (4) 
the atomizer spindle is lifted by the cam shaft, opening the passage 



Digiti 



zed by G00gk 



502 MACHINERY 

Table 1 — Data for Light Weight High Speed Engines 



Number 


Normal 


Maximum 


Normal 


Fuel Con- 


Weight 
Lb. About 


of 


Brake 


Brake 


R. p. m. 


sumption 
Lb. About 


Cylinders 


Horse Power 


Horse Power 


About 


6 


300 


330 


480 


0.52 


14,500 


6 


450 


500 


450 


0.50 


22,550 


6 


600 


660 


425 


0.49 


27,000 


6 


900 


975 


390 


0.48 


39,000 


6 


1,200 


1,275 


370 


0.48 


52,000. 


6 


1,500 


1,600 


300 


0.47 


65,000 


6 


2,000 


2,150 


270 


0.47 


86,000 



Table 2 — Data fob Heavy Weight Moderate Speed Engines 



Number 


Normal 


Maximum 


Normal 


Fuel Con- 


Weight 
Lb. About 


of 
Cylinders 


Brake 
Horse Power 


Brake 
Horse Power 


R. p. m. 
About 


sumption 
Lb. About 


6 


300 


350 


300 


0.49 


32,000 


6 


600 


650 


275 


0.47 


62,000 


6 


900 


1,000 


235 


0.46 


91,000 


6 


1,200 


1,300 


210 


0.46 


115,000 


6 


1,500 


1,600 


180 


0.45 


140,000 


6 


2,000 


2,100 


165 


0.44 


188,000 



The weights given include all auxiliary machinery and apparatus, such as water 
and oil pumps, fuel pumps, coolers and filters, as well as the compressed air starting 
and injecting apparatus, and thrust block. 

New London Shipbuilding Co. 

into the cylinder, and the injection air forces the oil lying in the 
atomizer into the hot charge in the form of a spray. The oil im- 
mediately ignites and further heats the charge of air and causes 
same to expand behind the piston and thereby transmit power to 
the crank shaft as steam does in a steam engine. There is no 
explosion and the pressure does not materially exceed the 500 lb. 
compression pressure, but owing to the additional heat supplied by 
the burning of the oil the expansion creates the power. 

The important features in the Southwark-Harris engine are 
that cold high-pressure air is never admitted into the working 
cylinders, and that the engine can be started from stone cold to full 
power in 10 seconds and can be started or reversed without cutting 
off the fuel from any of the main or working cylinders. 

The scavenging pump or low-pressure compressor is of the 



Digiti 



zed by G00gk 



DIESEL ENGINES 



603 



step piston type; that is, the piston of the scavenging pump is an 
enlarged extension of the main piston, working in its own cylinder 
below the working cylinder. It is while reversing and starting the 
engine on compressed air that the scavenging cylinder and step 
piston play an important part. The using of the step piston in air 
starting does away with the necessity of air starting valves in the 
cylinder head, the scavenging air being admitted to the working 
cylinder through ports in its circumference. The exhaust gases 
pass out through ports located opposite the scavenging ports and 
so arranged that the piston opens and shuts them at the correct 
time during its travel. 
The table below gives data on Southwark-Harris engines. 



Southwark-Harris Diesel Engines* 











Normal 


Approx- 




Number 


Dia. of 


Stroke, 
Ins. 


Dia. of 


Revo- 


imate 




of 


Cylinder, 


Shaft, 


lutions 


Weigh o 


I. h. p. 


Cylinders 


Ins. 


Ins. 


per 


Without 












Minute 


Wheel, Lb. 




2 


9 


13 


5 


300 


14,000 


120 


4 


9 


13 


5 


300 


21,500 


240 


6 


9 


13 


5 


300 


31,000 


360 


8 


9 


13 


5 


300 


40,000 


480 


4 


12 


21 


8 


200 


47,000 


450 


6 


12 


21 


8 


200 


66,000 


675 


8 


12 


21 


8 


200 


85,000 


900 


4 


16 


28 


11 


150 




800 


6 


16 


28 


11 


150 




1,200 


8 


16 


28 


11 


150 




1,600 



* Southwark-Harris Co., Philadelphia, Pa. 

Diesel engines, built by Burmeister and Wain, Copenhagen, 
Denmark, have been installed on many large vessels. These 
engines are of the 4-cycle type, and all the large sizes have 6 cylin- 
ders cast in blocks of 3. With the present design it is claimed there 
is no danger of cracked cylinders as liners are fitted of special grade 
cast iron similar to the heads of the piston. The air compressors 
are self-contained and are operated from the end of the crank shaft. 
Six A frames support the cylinders and to them are bolted the cross- 
head guides. The frames have through bolts on both sides which 
extend from the top of the cylinders to the under side of the bed 
plate bearings. The pistons are only long enough to contain the 

Digitized by vjOOQ 1C 



504 



MACHINERY 



rings and are cooled with sea water like the cylinders. One of the 
largest built (1916) was a 6-cylinder, 4-cycle with cylinders 29.6 ins. 
diameter by 44 ins. stroke, giving 340 h. p. per cylinder at 100 r. p. m., 
with a total of 2,040 h. p. for the engine. See Fig. 87a. 

Refer to the table of Motor Ships and note the 336-footer in 
which were installed two Burmeister and Wain engines. Each is 
of the 4-cycle type with six cylinders 21 x /i ins. diameter by 28 % 
ins. stroke, and develops about 1,000 h. p. The engines are inclosed 
and are fitted with a high-pressure oiling system. The valve gear 
is reversible by sliding the cam shaft and substituting a special 
set of cams for reversing. Each cylinder has its own fuel pump, 
which draws from day settling tanks of 12-hour capacity. In the 
exhaust lines are two mufflers, one at each engine and one in the 
deck house above with branches to the masts, the masts being hol- 
low and of steel. 




Figure 87. — Section Through Cylinder of a Werkspoor Engine. 



Another make of Diesel engine which has been built in sizes up 
to 2,000 h. p. is the Werkspoor, built by the Netherlands Eng'g Co., 
Amsterdam, Holland, and by the Newport News Shipbuilding 
Company, and New York Shipbuilding Company, in the United 
States. One of the features of this engine is its accessibility, it 
being of the open type with the cylinders mounted on steel columns 
on both sides, and at the back are cast iron frames on which are 
the crosshead guides. The cylinder design (see Fig. 87) differs 
from other four-cycle Diesels, there being no detachable heads, 
and the absence of flanges affords proper water cooling all around 
that part of the combustion chamber which is exposed to the 



jvJ^X^ 



CRAIG ENGINES 



505 



greatest heat. The engine can be reversed from full ahead to 
astern in about 5 seconds, and can be started up from cold in 3 to 
5 seconds, on an air pressure of 250 lb. per square inch. The 
engine is self-contained and does not require a large amount of 
separate auxiliary machinery. The exhaust gases are led in some 
vessels to a donkey boiler and sufficient heat is obtained to maintain 
a pressure of 100 to 120 lb. when at sea. The average consumption 
of Werkspoor engines including auxiliaries is about .3 lb. of oil per 
i. h. p. per hour. 





Werkspoor Diesel Engines 


i 




Number of 
Cylinders 


Diameter 

of 
Cylinders 


Stroke 


Revs, 
per 
Min. 


Approximate 

Weight with 

Compressor 

and Pumps, 

Founds 


Normal 
B. H. P. 


Normal 
I. H. P. 


4 


12^ 
16« 


23J3 


200 


51,520 


200 


265 


3 


26^ 


200 


67,200 


250 


300 


4 


15JS 


26^ 


175 


80,640 


340 


450 


4 


19^ 


31M 


140 


134,400 


450 


600 


6 


WA 


265^ 


175 


130,000 


475 


635 


6 


20^ 


35^ 


130 


215,040 


825 


1100 


6 


22 


39M 


125 


273,280 


1020 


1360 


6 


MM 


43^ 


120 


349,440 


1320 


.1760 


6 


26 


47M 


110 


425,600 


1500 


2000 



Still another make is the Craig (James Craig Engine and Machine 
Works, Jersey City, N. J.), the builder guaranteeing less than one 
half pound of fuel per brake horse power per hour. Almost any 
grade of fuel oil can be burned, but there are some, owing to high 
sulphur content, great viscosity, etc., that are undesirable. Craig 
engines are of the 4-cycle, direct reversible type and are built in 
sizes from 180 to 1,000 h. p. with 6 to 8 cylinders, each cylinder 
being a separate casting bolted to a rigid table carried on stanchions 
mounted in the bed plate. This style of framing affords an open 
crank case. 

The valves in the cylinder heads are operated by push rods 
and rockers, so arranged that the heads can be detached and re- 
placed without disturbance of any adjustments. At the back of 
the cylinders are located the lower exhaust ports, controlled by 
valves through which the exhaust pressure's released at the end of 
the power stroke. 

Digitized by LiOOQ LC 



506 



MACHINERY 



A compressor furnishes the air for the injection fuel and for 
replenishing the storage bottles containing the air for starting 
and reversing. The compressor is of the two-stage type with 
intermediate and final air coolers of large surfaces. 

The engine is reversed by affixing to the front cam shaft suit- 
able cams arranged to function the valves for the ahead motion 
and suitable cams to function the valves for the astern motion, 
together with suitable inclines on the sides of the cams to lift and 
lower the push rods when necessary; and by arranging the cam 
shaft to move longitudinally in its bearings. 

Fuel is fed to the injection valves by a single pump with a stroke 
that is variable at will, giving close regulation of the engine speed. ' 
From the pump the fuel is forced through adjustable distributor 
valves with graduated scales, fitted in convenient positions on 
the engine. Below are tables of sizes. 



Heavy Duty Series 



B. h. p. 


Cylinders 


Dimensions 


R. p. m. 


Wt. of Engine 


200 
360 
500 


Six 

Six 

Eight 


9K" X 12" 
12^" X 15* 
12J^" X 15" 


420 
375 
380 


16,500 lb. 
28,000 lb. 
37,000 lb. 


Slow Speed Series 


200 
300 
540 


Six 
Six 
Si£ 


9%* X 15* 
12" X 18" 
16" X 24" 


320 
260 
200 


21,600 lb. 
34,000 lb. 
64,500 lb. 



Diesel Engine Installations. — The auxiliaries may be grouped 
under two headings: (1) those for operating the ship; and (2) those 
pertaining to the propelling equipment. 

Under (1) is included bilge, ballast, fire, sanitary, and fresh 
water pumps common to both Diesel and steam driven vessels, 
as also the refrigerating plant and the electric outfit, although the 
latter may have a direct connected Diesel engine and generator. 
Cargo winches, windlasses, capstans, and steering gear are gener- 
ally steam operated but could be electric, the steam being furnished 
by a donkey boiler. 

The propelling equipment includes air starting reservoirs that 



JvJ^VLV^ 



PIPING AND TUBING 507 

may be arranged vertically against the bulkheads or horizontally 
in tiers, while the fuel injection air tank is close to the engine, the, 
piping being of copper. 

The main engine cylinders are cooled by sea water supplied by 
a pump driven from the engine. The water may be discharged into 
a tank above the engine, thus flowing by gravity through the cyl- 
inder jackets and thence overboard. 

Exhaust piping is led to a muffler that may be placed in a stack 
extending above the deck. The piece next to the engine is of 
cast iron, so as to withstand the high temperatures of the exhaust 
gases, although the rest of the piping may be ordinary wrought iron 
which should be covered with asbestos or other insulating material. 

The turning gear is generally arranged with teeth in the periphery 
of the flywheel and may be operated by hand, steam, compressed 
air, or electricity. 

See table of Motor Ships and Fig. 87a. 

PIPING, TUBING, VALVES AND FITTINGS 

Piping and Tubing. — When the size of a wrought iron pipe is 
given as J^ inch, neither the actual outside nor inside diameter is 
this dimension; this is an arbitrary dimension that has been fixed 
by the pipe manufacturers. See tables on pages 508-9. Wrought 
iron pipe is usually joined by screwed couplings on all sizes below 
5 ins., and above this size by flanges with bolts. 

Butt-welded wrought iron pipe is 70% as strong as similar butt- 
welded steel pipe, and lap- welded wrought iron pipe is 60% as 
strong as similar lap-welded steel pipe. In steel the butt weld 
averages 73% of the tensile strength and the lap weld 92% of the 
tensile strength of the material. 

The principal advantage claimed for wrought iron pipe over 3teel 
is its resistance to rust and corrosion. To distinguish wrought iron 
pipe from steel, after removing all marks of the cutting off tool 
and having the end of the pipe smooth, suspend the pipe so that the 
end will dip into a solution of 10 parts water and 4 parts sulphuric 
acid, 1.84 sp. gr., say X A ounce acid and l\i ounces water. Keep 
immersed for about an hour. Remove the pipe, wash off the acid 
and dry quickly with a soft rag. If the pipe is steel, the end will 
present a solid unbroken surface, if iron the end will show ridges 
or rings indicating different layers of iron and streaks of cinder. 

There are certain trade customs as follows: The permissible 
variation in weights is 2J/£% below standard weights given in tables 

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Digiti 



zed by G00gk 



510 



MACHINERY 



and not over 5% above standard weights. All standard weight 
pipe unless otherwise ordered, is shipped in random lengths, threaded 
and furnished with couplings. Extra strong and double extra strong 
pipe, unless otherwise ordered, is shipped with plain ends and in 
random lengths without couplings. Random lengths for strong and 
double extra strong are considered to be from 12 to 24 ft., mill to 
have the privilege of supplying not exceeding 5% of the total order 
in lengths from 6 to 12 ft. For bundling schedule see page 20. 

"National" Stationary and Marine Boiler Tubes 
All Weights and Dimensions are Nominal 



Outside Diameter, Inches 


Thickness 
Inches 


Thicknesf? 
Birming- 
ham Wire 
Gauge 


Weight 
per Foot, 
Pounds 


Test Pressure, Lb. 


beamless 




Seamlc 




Hot 


Coir 


Lap 
i Weld 


»ss Lap Weld 


Finish 


Finis 


h 














1 




.095 


13 


.918 


100C 


) 




V/a 




.095 


13 


1.171 


100c 


> 




IX 




.095 


13 


1.425 


100c 


) 




iy 4 


! 'ik 


.095 


13 


1.679 


100c 


) 750 


2" 


2 


2 


.095 


13 


1.932 


100c 


) 750 


2*A 


2V A 


: 2K 


.095 


13 


2.186 


10(X 


) 750 


2V2 


2M 


1 2J4 


.109 


12 


2.783 


1(XX 


) 750 


2% 


2*/ 4 


: 2^ 


.109 


12 


3.074 


100( 


) 750 


3 


3 


3 


.109 


12 


3.365 


1(XX 


) 750 


3M 


3^ 


1 3K 


.120 


11 


4.011 


100( 


) 750 


3H 


&A 


i 3^ 


.120 


11 


4.331 


100( 


) 750 


s% 


&/A 


1 3^ 


.120 


11 


4.652 


1(XK 


* 750 


4 


4 


4 


.134 


10 


5.532 


1(XK 


) 750 


VA 


± l A 


i 4J4 


.134 


10 


6.248 


MXX 


) 500 


5 


5 


5 


.148 


9 


7.669 


1<XX 


) 500 








6 


.165 


8 


10.282 




500 








7 


.165 


8 


12.044 




500 








8 


.165 


8 


13.807 




500 








9 


.180 


7 


16.955 




500 








10 


.203 


6 


21.240 




500 








11 


.220 


5 


25.329 




500 








12 


.229 




28.788 




500 








13 


.238 


i 


32.439 




500 



In tubing the actual outside diameter is given. Boiler tubes are 
generally of charcoal iron, lap welded. The physical properties of 
boiler tubes as manufactured by the National Tube Co., Pittsburgh, 
Pa., are as follows: 



Digiti 



zed by G00gk 



BOILER TUBES 



511 





"National" 
Spellerized 


Shelby 

Seamless 

Cold-drawn 


Shelby 

Seamless 

Hot finished 


Tensile Strength, lb. per sq. in 

Elastic Limit, lb. per sq. in 

Elongation ui 8 inches, per cent 

Reduction of area, per cent 


58,000 
36,000 

22 

55 


52,000 
32,000 

22 

50 


62,000 

42,000 

22 

48 



Iron and Steel Lap-Welded Boiler Tubes 



External 


Imperial 


Equiva- 


External 


Imperial 


Equiva- 


Diameter 


Wire 


lents in 


Diameter 


Wire 


lents in 


in Inches 


Gauge 


Inches 


in Inches 


Gauge 


Inches 


IN 


13 


.092 


5N 


7 


.176 


IN 


13 


.092 


6 


7 


.176 


IN 


13 


.092 


6N 


7 


.176 


IN 


13 


.092 


6N 


7 


.176 


IN 


13 


.092 


6M 


7 


.176 


IN 


13 


.092 


7 


7 


.176 


2 


12 


.104 


7N 


5 


.212 


2N 


12 


.104 


7Vi 


5 


.212 


2M 


12 


.104 


7% 


5 


.212 


2% 


11 


.116 


8 


5 


.212 


2H 


11 


.116 


8*4 


3 


.252 


w% 


11 


.116 


W2 


3 


.252 


2M 


11 


.116 


m 


3 


.252 


2N 


11 


.116 


9 


3 


.252 


3 


11 


.116 


9N 


3 


.252 


3N 


10 


.128 


9N 


3 


.252 


3H 


10 


.128 


9N 


3 


.252 


3M 


10 


.128 


10 


3 


.252 


4 


9 


.144 


WH 


2 


.276 


4N 


9 


.144 


\m 


2 


.276 


VA 


9 


.144 


10% 


1 


.300 


4N 


8 


.160 


11 


1 


.300 


5 


8 


.160 


UN 


1 


.300 


5M 


8 


.160 


12 


1 


.300 


5H 


7 


.176 









Brass tubes have a maximum tensile strength of 40,000 lb. per 
square inch when made with a mixture to the ratio of 60 lb. of cop- 
per to 40 lb. of zinc, and will stand bending on themselves and 
flanging when either hot or cold without fracture. 

Copper tubes made from absolutely pure copper have a maximum 
tensile strength of 30,000 lb. 

Digitized by LiOOQ 1C 






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II 



513 



Digiti 



H-l 

zed by G00gk 



Table Showing Approximate Weight 

Stubs 7 or Birmingham Gauge 

(To ascertain the weight of Seamless Copper Tubing 



Gauge No. 




To determine weight per foot of a tube of a given 
weights given below under 



Gauge No. 


3 


4 


5 


6 


7 


8 





10 


11 


12 


13 


14 


Increase in 
Lb. per Ft. 


1.5487 


1.3077 


1.1174 


.9514 


.7480 


.6285 


.5057 


.4145 


.3324 


.2743 


.2084 


.1590 



The above Weights are theoretically correct, but variation* mutt be 
514 



Per Foot op Seamless Brass Tubing 

Measured in Outside Diameters. 

Add 5 per cent to the Weights of Brass Tubing.) 



Gauge No. 


15 


16 


17 


18 


19 


20 


21 


22 


23 


24 


25 


26 


27 


Thickness of each 
No. in Decimal 
Parts of Inch 


.072 


.065 


.058 


.049 


.042 


.035 


.032 


.028 


.025 


.022 


.020 


.018 


.016 


Frac. of Inch, Cor- 
responding Closely 
to Gauge Nos. 




A 




V« 






V« 












l /u 


Dia. Tubes, Ins. 
y % 




.045 

.092 

.139 

.186 

.233 

.279 

.326 

.373 

.420 

.467 

.514 

.561 

.608 

.655 

.70 

.79 

.89 

.98 

1.08 

1.17 

1.26 

1.36 

1.45 

1.55 

1.64 

1.73 

1.83 

1.92 

2.01 

2.11 

2.20 

2.30 

2.39 

2.48 

2.58 

2.67 

2.76 

2.86 


.045 
.087 
.129 
.170 
.212 
.254 
.296 
.338 
.380 
.421 
.463 
.505 
.547 
.589 
.63 
.71 
.80 
.88 
.96 
1.05 
1.13 
1.22 
1.30 
1.38 
1.47 
1.55 
1.63 
1.72 
1.80 
1.89 
1.97 
2.05 
2.14 
2.22 
2.30 
2.39 
2.47 
2.56 


.043 

.078 

.114 

.149 

.184 

.220 

.255 

.290 

.326 

.361 

.396 

.432 

.467 

.502 

.54 

.61 

.68 

.75 

.82 

.89 

.96 

1.03 

1.10 

1.17 

1.24 

1.32 

1.39 

1.46 

1.53 

1.60 

1.67 

1.74 

1.81 

1.88 

1.95 

2.02 

2.09 

2.16 


.040 

.070 

.101 

.131 

.161 

.192 

.222 

.252 

.283 

.313 

.343 

.373 

.404 

.434 

.46 

.52 

.59 

.65 

.71 

.77 

.83 

.89 

.95 

1.01 

1.07 

1.13 

1.19 

1.25 

1.31 

1.37 

1.43 

1.49 

1.55 

1.62 

1.68 

1.74 

1.80 

1.86 


.036 

.062 

.087 

.112 

.137 

.163 

.188 

.213 

.238 

.264 

.289 

.314 

.339 

.365 

.389 

.439 

.490 

.540 

.591 

.641 

.692 

.742 

.793 

.843 

.894 

.944 

.995 

1.045 

1.096 

1.146 

1.197 

1.247 

1.298 

1.348 

1.399 

1.449 

1.50 

1.55 


.084 

.057 

.080 

.104 

.127 

.150 

.173 

.196 

.219 

.242 

.265 

.288 

.311 

.334 

.358 

.404 

.450 

.496 

.542 

.588 

.635 

.681 

.727 

.773 

.819 

.866 

.912 

.958 

1.004 

1.050 

1.096 

1.143 

1.189 

1.235 

1.281 

1.327 

1.373 

1.42 


.031 
.051 
.072 
.092 
.112 
.132 
.152 
.173 
.193 
.213 
.233 
.253 
.274 
.294 
.314 
.351 
.395 
.435 
.476 
.516 
.556 
.597 
.637 
.678 
.718 
.758 
.799 
.839 
.880 
.920 
.960 
1.001 
1.041 
1.082 
1.122 
1.162 
1.203 
1.243 


.029 
.047 
.065 
.083 
.101 
.119 
.137 
.155 
.173 
.191 
.209 
.227 
.245 
.263 
.281 
.317 
.354 
.390 
.426 
.462 
.498 
.534 
.570 
.606 
.642 
.678 
.714 
.750 
.786 
.822 
.859 
.895 
.931 
.967 
1.003 
1.039 
1.075 
1.111 


.026 
.042 
.058 
.074 
.090 
.106 
.121 
.137 
.153 
.169 
.185 
.201 
.217 
.232 
.248 
.280 
.312 
.343 
.375 
.407 
.439 
.470 
.502 
.534 
.566 
.597 
.629 
.661 
603 


.024 
.039 
.053 
.067 
.082 
.096 

111 
.125 
.140 
.154 
.169 
.183 
.107 
.211 
.226 
.255 
.284 
.313 

342 
.371 
.399 
.428 
.457 
.486 
.515 
.544 
.573 


.022 
.035 
.048 
.061 
.074 
.087 
.100 
.113 
.126 
.139 
.152 
.165 
.178 
.191 
.204 
.230 
.256 
.282 
.308' 
.334 
.360 
.386 
.412 


0?0 


A 


.096 

.148 

.200 

.252 

.304 

.356 

.408 

.460 

.511 

.563 

.645 

.667 

.719 

.77 

.87 

.98 

1.08 

1.19 

1.29 

1.39 

1.50 

1.60 

1.71 

1.81 

1.91 

2.12 
2.23 
2.33 
2.43 
2.54 
2.64 
2.74 
2.85 
2.95 
3.06 
3.16 


03? 


y K 


043 


A 


055 


% 


066 


A 


078 


J*..~ 

w 


.089 
101 


Y % 


11? 


\\ 


124 


s i 


136 


«/m 


148 


y H 


159 


»/m 


171 


1 


18? 


lVg 


205 


m 


??8 


1=4 


?51 


iu 


?74 


i£ :::.:::: 




IX 




1*8 




2 

214 




2 l 4 






2 3 s 










2H 














2% 


.724 
.756 
.788 
.820 
.851 
.883 
.915 
.946 
.978 
















zy H 




3H 








3*6 








zv 2 








TfiA 








3»4 








VA 





Inside Diameter, add to weights in above list the 
corresponding gauge numbers. 



Gauge No. 


15 


16 


17 


18 


19 


20 


21 


22 


23 


24 


25 


26 


27 


Increase in 
Lb. per Ft. 


.1197 


.0975 


.0777 


.0554 


.0407 


.0283 


.0230 


.0181 


.0144 


.our 


.0092 


.0075 


J0059 



expected in practice. From Catalogue of U. T. Hungerford Co. 

515 



y Google 



516 



MACHINERY 



Table Showing Approximate Weight 

Stubs' or Birmingham Gauge. 

(To ascertain the weight of Seamless Copper Tubing 



Gauge No. 


3 


4 


5 


6 


7 


8 


9 


10 


11 


12 


Thickness of each 
No. in decimal 
Parts of Inch 


.250 


.238 


.220 


.203 


.180 


.165 


.148 


.134 


120 


.109 


Prac. of Inch, Cor- 
responding Closely 
to Gauge Nos. 


H 


»/« 




»/<* 


A 


»/e4 


V« 




K 




Dia. Tubes, Ins. 


11.19 
11.57 
11.94 
12.32 
12.69 
13.06 
13.44 
13.81 
14.18 
14.56 
14.93 
15.31 
15.68 
16.05 
16.43 
16.80 
17.17 
17.92 
18.67 
19.42 
20.16 
20.91 
21.66 
22.41 
23.07 
23.82 
24.56 
25.30 


10.33 
10.68 
11.02 
11.36 
11.71 
12.05 
12.39 
12.74 
13.08 
13.42 
13.77 
14.11 
14.45 
14.80 
15.14 
15.48 
15.83 
16.51 
17.20 
17.89 
18.57 
19.26 
19.95 
20.64 
21.27 
21.95 
22.62 
23.30 


9.60 
9.91 
10.23 
10.55 
10.87 
11.18 
11.50 
11.82 
12.14 
12.45 
12.77 
13.09 
13.41 
13.72 
14.04 
14.36 
14.67 
15.31 
15.94 
16.58 
17.21 
17.85 
18.48 
19.12 
19.69 
20.32 
20.96 
21.60 


8.90 
9.19 
9.48 
9.77 
10.07 
10.36 
10.65 
10.95 
11.24 
11.53 
11.82 
12.12 
12.41 
12.70 
13.00 
13.29 
13.58 
14.17 
14.75 
15.34 
15.92 
16.51 
17.10 
17.68 
18.20 
18.80 
19.37 
19.97 


7.94 
8.20 
8.46 
8.72 
8.98 
9.24 
9.50 
9.76 
10.02 
10.28 
10.53 
10.79 
11.05 
11.31 
11.57 
11.83 
12.09 
12.61 
13.13 
13.65 
14.17 
14.69 
15.21 
15.73 
16.33 
16.87 
17.38 
17.90 


7.31 
7.54 
7.78 
8.02 
8.26 
8.50 
8.73 
8.97 
9.21 
9.45 
9.69 
9.92 
10.16 
10.40 
10.64 
10.88 
11.12 
11.59 
12.07 
12.54 
13.02 
13.50 
13.97 
14.45 
15.03 
15.51 
15.99 
16.47 


6.58 
6.79 
7.01 
7.22 
7.43 
7.65 
7.86 
8.07 
8.29 
8.50 
8.71 
8.93 
9.14 
9.35 
9.57 
9.78 
9.99 
10.42 
10.85 
11.28 
11.70 
12.13 
12.56 
12.98 
13.49 
13.91 
14.35 
14.47 


5.98 
6.17 
6.37 
6.56 
6.75 
6.94 
7.14 
7.33 
7.53 
7.72 
7.91 
8.11 
8.3) 
8.49 
8.69 
8.88 
9.07 
9.46 
9.85 
10.23 
10.62 
11.01 
11.39 
11.78 
12.22 
12.62 
13.01 
13.40 


5.37 
o.55 
5.72 
5.89 
6.06 
6.24 
6.41 
6.58 
6.76 
6.93 
7.10 
7.28 
7.45 
7.62 
7.80 
7.97 
8.14 
8.49 
8.84 
9.18 
9.53 
9.87 
10.22 
10.57 
10.96 
11.32 
11.66 
12.00 


4.89 


4Vd 


5.05 


AVi. 


5.21 


m 


5.37 


4^4 


5.52 


452 


5.68 


\\i :. 


5.84 


J&. ..:::: 


6.00 


5 


6.15 


5H 


6.31 


5$.::.::.: 


6.47 


5U 


6.62 


5*£ 


6.78 


h% \ 


6.94 


fM\ 


7.10 


514 


7.25 


6 


7.41 


6^ 


7.72 


6V$ •.. 


8.04 


6'4 


8.35 


7 


8.67 


1M 


8.98 


7W 


9.30 


7J? 


9.61 


8 


9.97 


%M 


10.30 


8H 


10.61 


8%:::. ::::::::.. 


10.92 







To determine weight per foot of a tube of a given 
weights given below under 



Gauge No. 


3 


4 


5 


6 


7 


8 


9. 


10 


11 


12 


Increase in 
Lb. per Foot 


1.5487 


1.3077 


1.1174 


.9514 


.7480 


.6285 


.5057 


.4145 


.3324 


.2743 



The above Weighti are theoretically correct, 



Digiti 



zed by G00gk 



BRASS TUBING 



517 



Per Foot op Seamless Brass Tubing 

Measured in Outside Diameters. 

Add 5 per cent to the Weights of Brass Tubing.) 



Gauge No. 


13 


14 


15 


16 


17 


18 


19 


20 


21 


22 


23 


24 


Thickness of Each 
No. in Decimal 
Parts of Inch 


.095 


.083 


.072 


.065 


.058 


.049 


.042 


.035 


.032 


.028 


.025 


.022 


Frac. of Inch, Cor- 
responding Closely 
to Gauge Nos. 


V* 


V«4 




A 




Vn 






V« 








Dia. Tubes, Ins. 
4 


4.28 
4.42 
4.56 
4.69 
4.83 
4.97 
5.11 
5.24 
5.38 
5.52 
5.65 
5.79 
5.93 
6.07 
6.20 
6.34 
6.48 
6.75 
7.03 
7.30 
7.57 
7.85 
8.12 
8.40 
8.71 


3.75 
3.87 
3.99 
4.11 
4.23 
4.35 
4.47 
4.59 
4.71 
4.83 
4.95 
5.07 
5.19 
5.31 
5.43 
5.55 
5.67 
5.91 
6.15 
6.39 
6.63 
6.87 
7.11 
7.35 
7.63 


3.26 
3.37 
3.47 
3.58 
3.68 
3.78 
3.89 
3.99 
4.09 
4.20 
4.30 
4.41 
4.51 
4.61 
4.72 
4.82 
4.93 
5.13 
5.34 
5.55 
5.76 
5.96 
6.17 
6.38 
6.64 


2.95 
3.05 
3.14 
3.23 
3.33 
3.42 
3.52 
3.61 
3.70 
3.79 
3.89 
3.98 
4.08 
4.17 
4.26 
4.36 
4.45 
4.64 
4.83 
5.01 
5.20 
5.30 
5.58 
5.76 
7.05 


2.64 
2.72 
2.81 
2.89 
2.97 
3.06 
3.14 
3.22 
3.31 
3.39 
3.48 
3.56 
3.64 
3.73 
3.81 
3.89 
3.98 
4.15 
4.31 
4.48 
4.65 


2.23 
2.30 
2.38 
2.45 
2.52 
2.59 
2.66 
2.73 
2.80 
2.87 
2.94 
3.01 
3.08 
3.15 
3.22 
3.29 
3.37 
3.51 
3.65 
3.79 
3.93 


1.92 
1.98 
2.04 
2.10 
2.16 
2.22 
2.28 
2.34 
2.40 
2.46 
2.52 
2.58 
2.65 
2.71 
2.77 
2.83 
2.89 


1.601 
1.651 
1.702 
1.752 
1.803 
1.853 
1.904 
1.954 
2.005 
2.055 
2.106 
2.156 
2.207 
2.257 
2.308 
2.358 
2.409 


1.466 
1.512 
1.558 
1.601 
1.650 
1.697 
1.743 
1.789 
1.835 
1.881 
1.928 
1.974 
2.02 


1.284 
1.324 
1.364 
1.405 
1.445 
1.486 
1.520 
1.566 
1.607 


1.147 
1.183 
1.219 
1.255 
1.291 


1.010 


4H 




4 l A 




4% 




4H 




m 

4% 




4J4 






5 




5% 






5 l 4 








hV % 








5H 








b% 








5H 










5% 










6 










6*4 










6^6 














6*£ 














7 














714 














71^ 


















754 


















8 


















8H 


















8 l A 


























$% 





















































Inside Diameter, add to weights in above list the 
corresponding gauge numbers. 



Gauge No. 


13 


14 


15 


16 


17 


18 


19 


20 


21 


22 


23 


24 


Increase in 
Lb. per Ft. 


.2084 


.1590 


.1197 


.0975 


.0777 


.0554 


.0407 


.0283 


.0236 


.0181 


.0144 


.0112 



but tariationa must be expec