BOYS' BOOK

OF

MODEL BOATS

[Illustration: ©_Jack Sussman_

A TWO-FOOT STEAMBOAT

Making her way across the park pond. Ten miles an hour is a common speedfor a boat of this type]

BOYS' BOOK

OF

MODEL BOATS

BY RAYMOND FRANCIS YATES

 WITH NUMEROUS ILLUSTRATIONS FROM DRAWINGS AND PHOTOGRAPHS

[Illustration]

 NEW YORK THE CENTURY CO. 

 Copyright, 1920, by THE CENTURY CO. 

 PRINTED IN U. S. A. 

 TO LAVERNE YATES A BUILDER OF MODEL BOATS

PREFACE

EVERY boy likes to build boats. The interest in boats seems to be bornin the race. The little three-year-old chap is instinctively attractedby a puddle of water in which to sail his "boat, " which may take theform of a piece of shingle or common board. Few men have passed throughtheir boyhood days without having built boats at some time. 

The author was an ardent boat-builder, and he well remembers how hecombed the Children's Department of the local library in search of abook that would tell him something about boats, and especially forinformation regarding the construction of models. He found books onmodel airplanes, toys, electricity, radio, and chemistry, but alas!nothing about model boats. He vowed then that when he became a man hewould write a book on model boats--a book that would contain all thetreasured information he had accumulated during his boat-buildingyears. 

This book is the result of that vow, and the author earnestly hopes thatit will gladden the heart of every boy who builds and sails a boat. There are probably few happier moments in a boy's life than when he seeshis little model steamer proudly make her way across the park pond, orhis little sail-boat respond to the summer breeze. 

The author takes this opportunity to thank his wife, who acted as hisamanuensis in the preparation of this manuscript. 

 RAYMOND FRANCIS YATES. 

CONTENTS

 CHAPTER PAGE

 I WHY A BOAT FLOATS 3

 II THE HULL 12

 III HOW TO MAKE SIMPLE BOATS, WITH AND WITHOUT POWER DRIVE 26

 IV STEAM AND ELECTRIC PROPULSION 42

 V AN ELECTRIC LAUNCH 66

 VI A STEAM LAUNCH 75

 VII AN ELECTRICALLY DRIVEN LAKE FREIGHTER 91

 VIII AN ELECTRIC SUBMARINE-CHASER 98

 IX BOAT FITTINGS 107

 X THE DESIGN OF MODEL STEAM-ENGINES 126

 XI A MODEL FLOATING DRY-DOCK 135

 XII OPERATION OF FLASH STEAM POWER PLANTS FOR MODEL BOATS 149

 XIII SAILING YACHTS 164

 XIV TWO-FOOT SAILING YACHT 184

 APPENDIX 207

LIST OF ILLUSTRATIONS

 A two-foot steam boat _Frontispiece_

 FACING PAGE

 Getting ready for a trip 72

 All ready to go 73

 A powerful gasolene blow-torch 112

 Just after the race 113

 A twin-cylinder steam engine for model marine use 168

 A cup-winning model sail boat 169

BOYS' BOOK OF MODEL BOATS

BOYS' BOOK OF MODEL BOATS

CHAPTER I

WHY A BOAT FLOATS

BEFORE taking up the construction of any of the model power boatsdescribed in this book, it will be well for the young boat-builder tobecome acquainted with such terms as buoyancy, displacement, center ofgravity, etc. Knowledge of these subjects is more or less necessary ifsuccessful boats are to be made. Aside from this, they are terms thatevery boy who claims an interest in boats should understand. 

"How does a steel boat float?" is a question that many boys ask. Thereason they usually designate a steel boat is probably because steel isso much heavier than water. But many things heavier than water can bemade to float if they are in the form of a boat. Concrete, for instance, is now being used in ship construction, and this substance, whenreinforced with steel rods, is very much heavier than water. 

Before learning how a boat floats, what is known as "specific gravity"must be thoroughly understood. Gravity is a force that is continuously"pulling" everything toward the center of the earth. It is gravity thatgives a body "weight. " Some substances are heavier than others; or, tobe more correct, it is said that the specific gravity of one substanceis greater than that of another. It will be well to keep in mind thatspecific gravity merely refers to weight. It is simply a scientificterm. The specific gravity of a substance is always expressed by afigure that tells how much heavier any substance is than water, becausewater has been chosen as a standard. 

The specific gravity of water is 1. The specific gravity of gold is19. 26, meaning that it is about 19-1/4 times heavier than water. Thespecific gravity of a piece of oak is 0. 86, which shows that it is notquite so heavy as water. One cubic foot of water weighs 62. 42 pounds. It will be understood that a cubic foot of gold would weight 19. 26 x62. 42, because it is 19. 26 times heavier than water. A cubic foot ofoak, however, would weigh only 54 pounds, because it has been found thatit has a specific gravity of only 0. 86 which is less than water. 

[Illustration: FIG. 1]

A cubic foot of oak (see Fig. 1), with a weight of 54 pounds, will floatwhen placed in water. The cubic foot of brass (_B_), however, will notfloat, because it weights 8. 1 times as much as water. For the present, then, it can be said that a substance lighter than water will float inwater, but that substances heavier than water, such as iron, lead, gold, silver, etc. , will not float. If the cubic foot of oak (_A_) wereplaced in water, it would sink to the depth shown at _C_. When the blocksinks into the water, a certain amount of water will be forced away or"displaced"; that is, the block in sinking occupies a space that waspreviously occupied or filled with water. The oak block sinks to withina short distance of the top because the oak is really just a triflelighter than water. If a pine block were placed in the water it wouldsink only to the distance shown at _D_, since the weight of pine is lessthan oak, or only 34. 6 pounds per cubic foot. A pine block will, then, displace only about 34. 6 pounds of water, which leaves nearly half ofthe block out of the water. Thus, it will be seen that for a givenvolume (size) a cubic foot of wood will sink to a depth corresponding toits weight. Different kinds of wood have different weights. 

If a cubic foot of brass is placed in water, it will sink rapidly to thebottom, because the brass is much heavier than water. How is it, then, that an iron or concrete ship will float? If the cubic foot of brass isrolled or flattened out in a sheet, and formed or pressed into theshape of a boat hull, as shown in Fig. 2, it will float when placed uponthe surface of the water. Why is it that brass is caused to float inthis way, when it sank so rapidly in the form of a solid square?

[Illustration: FIG. 2]

It will be remembered that the pine and oak block were caused to floatbecause they displaced a greater weight of water than their own weight. This is just what causes the brass boat-hull to float. If the amount ofwater actually displaced by the hull could be weighed, it would be foundthat the weight of the water would be greater than the weight of thehull. It will be understood that the space occupied by the brassboat-hull is far greater than the space occupied by the block of brassbefore it was rolled out and formed into a hull. What is true of brassholds true of iron, steel, etc. A block of steel will not float, becausethe water it displaces does not weigh nearly as much as the block. Ifthis block, however, were rolled out into a sheet and the sheet formedinto a hollow hull, the hull would float, because it would displace avolume of water that would more than total the weight of the steel inthe hull. 

In the case of the brass boat-hull, it would be found that a greaterportion of the hull would remain out of the water. The hull, then, couldbe loaded until the top of it came within a safe distance from thewater. As the load is increased, the hull sinks deeper and deeper. Thecapacity of big boats is reckoned in tons. If a boat had a carryingcapacity of ten tons it would sink to what is called its "loadwater-line" (L. W. L. ) when carrying ten tons. As a load or cargo isremoved from a vessel it rises out of the water. 

What if the hull of a boat has a hole in it? If the hole is below thewater-line, water will leak in and in time completely fill the inside ofthe hull, causing the boat to sink. Also, if too great a load or cargowere placed in a boat, it would sink. It must be understood that waterleaking into a boat increases its load, and if it is not stopped it willcause the boat to sink. 

The center of gravity of a boat is a very important matter. First, attention will be directed to the meaning of "center of gravity. " If aone-foot ruler is made to balance (as shown in Fig. 3) at the six-inchmark, the point at which it balances will be very close to the center ofgravity. The real center, however, will be in the middle of the wood ofwhich the rule is composed. It should constantly be kept in mind thatthis "center of gravity" is a purely imaginary point. 

Look at Fig. 4. If wires are arranged in a wooden frame, as shown, thepoint where the wires cross will be the center of gravity if the squareformed by the wooden strips is solid. Every body, no matter what itsshape, has a center of gravity. The center of gravity is really animaginary point in a body, at the center of its mass. Oftentimesengineers are heard saying that the center of gravity of a certainobject is too high or too low. Fig. 5 shows the center of gravity in aboat. If the center of gravity in a boat is too high (as illustrated inFig. 6) the boat is said to be topheavy and unsafe. When a boat istopheavy or its center of gravity is too high, the boat is liable tocapsize. In fact, some very serious marine accidents have been caused bythis fault. 

[Illustration: FIG. 4]

[Illustration: FIG. 5]

[Illustration: FIG. 3]

[Illustration: FIG. 6]

The center of gravity (or center of weight) in a boat should be as lowas possible. A boat with a low center of gravity will be very stable inthe water and difficult to capsize. This is true of model boats just asmuch as it is true of large boats. The model boat builder must keep theweight of his boat as near the bottom as possible. For instance, if aheavy cabin were built on a frail little hull, the boat would be veryunstable and would probably capsize easily. 

CHAPTER II

THE HULL

MODEL boat-hulls are generally made by one of two methods. One method isthat of cutting the hull from a solid piece of wood. The other method iscommonly known as the "bread-and-butter" system. The hull is built up ofplanks laid on top one of another with marine glue spread between them. The last-mentioned method (which shall hereafter be called the built-upmethod) possesses many advantages over the first. 

Cutting a model boat-hull from a solid piece of wood is by no means asimple or easy task, especially for beginners. Of course, after severalhulls have been produced in this fashion, the worker becomes practisedin cutting them out. 

[Illustration: FIG. 7]

[Illustration: FIG. 8]

The construction of hulls on the built-up principle will be describedfirst. For the sake of convenience, the drawings of the boat-hull shownin Figs. 7 and 8 will be followed out. Before going further it will bewell to understand drawings of boat-hulls; that is, how to know thelines of a boat from a drawing. By the "lines" is meant its shape. Marine architects employ a regular method in drawing boat-hulls. Fig. 7shows the side of a boat and half of the deck plan. It will be seenthat this drawing does not tell much about the real shape of the boat, and if a hull were to be produced according to the shape given, thebuilder would have to use his own judgment as to the outline of the hullat different places. For convenience, the boat is divided into tensections, represented by the lines 0 to 10. It will be seen that theshape of the hull at section 2 will be different from the shape of thehull at section 8. Again, section 0 will be much narrower than section5. 

[Illustration: FIG. 9]

Now look at Fig. 8. Note the shape of the cross-section of the hull atthe different sections. For instance, the line at section 1 in Fig. 8represents the shape of the hull at section 1 in Fig. 7. It must beremembered, however, that this is only half of the section, and that theline 1 in Fig. 8 would have to be duplicated by another line to show thetrue shape. The cross-section of the boat at section 0 is shown in Fig. 9. One half of the drawing in Fig. 8 represents the forward half of thehull, and the other half represents the stern half of the hull. If theshape of the boat at section 10 is desired, the line 10 in Fig. 8 couldbe traced on a piece of tissue paper. The paper could then be folded inhalf and the line first made traced on the second half. This would thenproduce the section of the boat at point 10. Thus, by closely examiningFig. 8 the shape of the entire hull can be seen. 

[Illustration: FIG. 10]

If pieces of wire could be used to form the lines of the hull at thevarious sections, it would appear as shown in Fig. 10 when assembled. 

Notice that in Fig. 8 there is a load water-line, which the vesselsinks to when loaded, and the second and first load water-line, whichthe vessel sinks to when only partially loaded or when carrying no loadaside from its regular necessary equipment. The keel line of the boat isthe line that runs along the bottom from bow to stern. (The bow of theboat is the front and the stern the back. )

Motor-boating and marine magazines often publish the lines of differentboats, and if the young boat-builder understands how to read boatdrawings he will be able to make a model of any boat that is sodescribed. 

Directions will now be given regarding the method of producing aboat-hull similar to the lines shown in Figs. 7 and 8, by the built-upmethod of construction. 

First, it will be necessary to procure the lumber. Several clean whitepine boards will be very suitable to work with, and will not requiremuch skill in handling. Let us assume that the boat-hull is to measure22 inches in length, with a depth of 4 inches. The beam, which is thewidth of the boat at its widest point, will be 5 inches. (It will bewell to remember what the term "beam" means, since the term will beused constantly throughout the book. )

On a piece of heavy wrapping-paper draw the deck plan full size, thatis, 22 inches long by 5 inches at its widest point. Next cut out alongthe pencil line with a pair of shears. Now lay the paper outline on aplank and mark out the pattern on the wood. Repeat this process withthree more planks. When this is done, cut out the boards with a keyholesaw. 

[Illustration: FIG. 11]

After the boards are cut out mark them as shown in Fig. 11. The spacemarked out on the board must be sawed out in two of the boards, to formthe inside of the hull, if the boat is to carry some form of power, suchas a battery-motor, or steam-engine. After the lines are marked out, make a hole with a 3/4-inch bit, as shown in Fig. 12. Insert the point ofthe keyhole saw in one of these holes to start it and cut out thepiece. Treat the second board in the same way. The third board musthave a smaller portion cut out of the center, owing to the fact thatthis board is nearer the bottom of the hull, where the width of the boatis narrower. The width of the piece cut out in the third board shouldnot be more than 2 inches. 

[Illustration: FIG. 12]

When this work is done, a very thin layer of glue is placed over theboards, and they are then laid one on top of another. The boards arethen placed in a vise or clamp and allowed to remain there over night. In applying the glue, the builder should be careful not to put too muchon the boards. Too much glue is worse than not enough. It should bemerely a thin film. 

After the boards have been glued together the crude hull will appear, asshown in Fig. 13. 

[Illustration: FIG. 13]

At this point the hull sections from 0 to 10 must be marked off. Byreferring again to Fig. 7 it will be seen that the sections 0 to 1 and 9to 10 are not so far apart as the other sections. Section 0 is 1 inchfrom the bow of the boat and section 1 is 1 inch from section 0. Sections 2, 3, 4, 5, 6, 7, and 8 are all 1 inch apart. Section 9 is 1inch from 10 and 10 is 1 inch from the stern. Lines should be drawnacross the deck to correspond with these sections, which can be measuredoff with a ruler. It will now be necessary to cut some templates, orforms, from cardboard to guide the builder in bringing the hull toshape. It will be an easy matter to make these templates by followingFig. 8. A template of section 9 is shown in Fig. 14. It will be necessaryto make eleven templates, corresponding to the sections 0 to 10. Thetemplates should be cut from heavy cardboard so they will hold theirshapes. 

[Illustration: FIG. 14]

The hull of the boat is now placed in a vise and roughly brought toshape with a draw-knife. After it has been brought to shape by thismeans a spoke-shave is used. This little tool has an adjustable blade bymeans of which it is possible to regulate the cut. When the builderstarts to use the spoke-shave he should also start to use his templatesor forms, applying them sectionally to determine how much more wood hewill have to remove to bring the hull to shape. For instance, when he isworking in the vicinity of sections 5, 6, and 7 he will apply theseforms at the proper points occasionally to determine when enough woodhas been removed. This procedure is followed out the entire length ofthe boat, care being taken to see that both sides are the same and thattoo much wood is not removed, since there is no remedy for this mistake. The builder who proceeds carefully and is not in too great a hurry tofinish the work need not make this mistake. 

Of course, it will not be possible to bring the hull to a perfect finishwith a spoke-shave. This can be done, however, by the use of a coarsefile and sandpaper. The coarse file is used to take the rough marks ofthe spoke-shave away, and the marks left by the file are in turn removedby the sandpaper. The sandpaper must be applied unsparingly and alwayswith the grain. It will be necessary to use considerable "elbow grease"to obtain a good finish. 

[Illustration: FIG. 15]

Boat-hulls can also be hewn to shape from a solid block, but it will beunderstood that this method involves more work than the one justdescribed. Of course, the procedure of bringing the hull to shape by theaid of the draw-knife, spoke-shave, and templates is the same, but thehollowing out of the inside of the hull will be a much more difficultjob. However, with a couple of good sharp chisels and a gouge the workwill not be so difficult as at first appears. The use of an auger andbit will greatly aid in the work. After the outside of the hull isbrought to shape the wooden form is drilled with holes, as shown in Fig. 15. This will make it much easier to chip the wood away. After the majorportion of the wood has been taken out with the chisel, the gouge isbrought into use. The gouge should be used very carefully, since it willeasily go through the entire hull if it is not handled properly. For thebeginner it is not safe to make a hull less than 1/2 inch in thickness. Of course, it is not necessary to carefully finish the inside of thehull, since it is covered up with the deck and cabin. 

[Illustration: FIG. 16]

The solid hull has one advantage over the built-up hull. It is notaffected by moisture and it is therefore not so liable to warp and loseits shape. It will also stand more rough usage. 

[Illustration: FIG. 17]

[Illustration: FIG. 18]

[Illustration: FIG. 19]

There is still another method of producing a boat-hull. This hull isknown as the Sharpie type. A Sharpie hull is shown in Fig. 16. Themethod of producing a hull of this type will be seen quite clearly byreference to Fig. 17, which shows the boards and parts cut out ready toassemble. The boards are made from 1/8-inch mahogany, which can beobtained at any lumber-yard. First, the bow piece is cut to shape andcarefully finished. Then the two side pieces are fastened to it, asshown in Fig. 18. The screws used should be brass, since iron screwswill rust and cause trouble. Three screws should be used for each sideboard, and they should be driven into the bow piece so that the screwson one side will not interfere with those on the other. The firstcross-piece is then screwed in place, as shown in Fig. 19. The secondand third cross-pieces are then screwed in place and the back or sternpiece attached. The bottom of the boat is then carefully put in placewith small screws. It will be noticed that the bottom board of the boatis cut to fit the inside of the bottom. It is held in place with smallbrass brads. The crevices or seams along the bottom of the boat shouldbe carefully covered with pitch or marine glue to prevent leakage whenthe boat is in the water. The bow of the boat should be finished offnicely to a point with a heavy file or a wood-rasp. 

This type of hull is extremely easy to produce and it is capable ofcarrying a considerable load. However, it is not a good type to use forall kinds of boats. It makes a splendid little pleasure yacht orsubmarine-chaser, but for a torpedo-boat destroyer or a freighter itwould not be suitable. 

The young model boat builder is advised not to try to construct hullsfrom metal. This is a very difficult task even for the thoroughlyexperienced mechanic. Wood is much easier to work with and will producethe same results. 

CHAPTER III

HOW TO MAKE SIMPLE BOATS, WITH AND WITHOUT POWER DRIVE

THIS Chapter will be devoted to the construction of very simple types ofboats. The boats described will be constructed largely with blocks ofwood cut into various shapes and sizes. The results obtainable by thismethod of construction are surprising, and there are few types of boatsthat cannot be modeled by following the method. After the model-builderhas constructed a few boats along this principle he will be able toduplicate the general appearance of almost any craft he sees bycarefully planning and cutting the blocks he uses. 

The first boat described is a submarine. This is shown in Fig. 20. Fourblocks of wood form the basis of its construction, and these are cutfrom 1-inch stock, as shown in the drawing. Such a submarine can bemade practically any size up to 12 inches in length. Beyond this sizethey begin to look out of proportion and they are more difficult topropel. After nailing the blocks together as shown in the drawing, asmall piece of sheet brass is bent at right angles and tacked to thestern piece. This is to act as a bearing for the propeller. 

[Illustration: FIG. 20]

[Illustration: FIG. 21]

The propeller-shaft is bent into a hook over which rubber bands areplaced. The opposite end of the rubber bands are fastened to a screw-eyedriven into the under side of the bow. A heavy piece of copper wire isfastened to the stern of the boat by staples, and bent as shown. Arudder is then cut from thin sheet brass, and the end of it is bentaround a piece of wire larger in diameter than the wire used for therudder-post. It is then taken from this wire and slipped over the wireon the boat. It should be pinched in place by a pair of pliers, so thatit will stay in any position in which it is put. The end of the wire isbent over so that the rudder will not slip off. The boat can be steeredin a circle or it can be made to go straight, depending upon theposition of the propeller. 

The horizontal rudders are mounted forward, as shown. They are made fromthin sheet brass bent as indicated in the little insertion. A hole isdrilled in them as shown, and a screw is placed through these to holdthe rudders to the side of the craft. The screws should be tightened sothat the rudders will stay at any angle at which they are put. If theboat is to be submerged the rudders are pointed as shown. If the boat isto travel on the surface of the water the rudders are brought up into ahorizontal position or parallel with the deck. A little gray paintplaced on this model will greatly improve its appearance. 

Another submarine, more complicated than the one just described, isshown in Fig. 21. The body of this submarine is formed by a part of abroomstick or shovel-handle. This submarine is truer to type and can bemade with very little trouble. The piece of broomstick or shovel-handleis cut 22 inches in length. It is pointed at each end, and part of it isplaned off to form the upper deck. When this is done, a small flat pieceis cut as shown, and nailed or screwed to the flat portion. Theconning-tower and periscope are placed on the upper deck, as shown. Therudder on this craft is not made adjustable, so that it always travelsin a perfectly straight line. The horizontal rudders however, are madeadjustable, and the boat is therefore able to travel upon the surfaceor submerge, depending upon the position of the rudder. 

The power plant of this boat is made up of rubber bands. The powertransmission to the propeller is a little different than the onepreviously described. A gear and a pinion are salvaged from the works ofan old alarm-clock, and mounted on a piece of brass, as shown. A littlesoldering will be necessary here to make a good job. By using the gearmeshing with the pinion a considerable increase in the speed of thepropeller is obtained, and therefore the speed of the boat isconsiderably increased. The method of holding the power plant to thebottom of the boat is made very clear. In order to bring the boat downto the proper level in the water, a strip of sheet lead can be tacked tothe bottom. The builder should take care to get a piece of lead just thecorrect weight to leave the surface of the deck awash. A coat of graypaint will also greatly improve the appearance of this craft. 

[Illustration: FIG. 22]

[Illustration: FIG. 23]

[Illustration: FIG. 24]

Attention is directed to the construction of boats of different typesmade without power plants. Many interesting little crafts can beproduced in this way, and the energetic model-builder can produce awhole model harbor or dock-yard by constructing a number of boats ofdifferent types according to the following instructions. 

The first boat described will be the tug _Mary Ann_ shown in Fig. 22 andFig. 23. The blocks necessary to construct this boat are shown in Fig. 24. The hull of the boat is produced by three pieces of wood sawed outto the same shape with a keyhole saw and glued together. After the glueis dry the blocks are placed in a vise and the top one or deck block isplaned down as shown. It will be seen that the deck inclines slightlytoward the stern of the boat. When this is done the hull is turnedupside down and the bottom of the stern planed off as illustrated. Theoutside of the hull can be finished up with a sharp knife and ajack-plane. 

The little bow piece can also then be tacked in place. After this thepieces that form the hull can be nailed together from the bottom andfrom the top. This is quite necessary, for glue will not hold them inplace after the boat has become thoroughly soaked with water. 

The cabin and engine-room are shown very clearly in the illustration andlittle need be said about erecting this part of the craft. The two doorsand window on the side of the cabin are made by cutting out small piecesof cigar-box wood and gluing them to the cabin and engine-room. A goodsubstitute for the wood can be found in tin, but of course this wouldhave to be tacked on. The little skylight on the back of the tug is madeby a single block covered by two pieces of cigar-box wood. 

In order to stabilize the craft and to bring her down to the properwater-line, a lead keel must be nailed to the bottom. The weight of thiskeel will have to be adjusted until the boat rests properly in thewater. The reader will notice that no dimensions have been given forthis boat. This is because most boys will wish to build different sizedboats, and therefore it has not been deemed advisable to dimension theboats described in this Chapter. What the author desires to do is toimpart the principles of construction, so that every boy may use his owningenuity in regard to size and proportion of length to beam. 

If tugs are constructed according to the design outlined above, themodel boat builder will also desire to have something that the tug canhaul. A very simple barge for this purpose is outlined in Figs. 25 and26. This is formed of a single slab with the ends cut at an angle asillustrated. A square flat piece is then tacked to the upper deck, whichacts as a cover. Four posts are then put in place in the same way asthose on the tug. One is placed in each corner. A boat or a scow likethis is generally painted red, and the model described can be made tolook much more realistic by painting it this color. 

[Illustration: FIG. 25]

[Illustration: FIG. 26]

[Illustration: FIG. 27]

[Illustration: FIG. 28]

These barges are so easy to construct that the model-builder should makethree or four of them at a time. If the pieces for several are cut outat the same time, the construction will be just that much easier. If theboat does not sink far enough into the water, a piece of lead should beplaced on the bottom to bring it down. This piece of lead should beplaced as near the center as it is possible to get it. Otherwise theboat will list or tip at one end or the other. With a little patienceand care the weight can be so adjusted on the bottom as to bring thescow to a perfectly level position. The reader will understand that thewater-line of a scow or any boat made according to the directions inthis book will depend largely upon the nature of the wood. In the firstChapter of the book it was pointed out that the specific gravity ofdifferent woods varies, and therefore the buoyancy will vary. 

A model freighter is shown in Fig. 27. The hull of this boat can beformed by two 1-1/2-inch planks. These will require a little hard workto cut out; but, on the other hand, the effort will be entirelyjustified by the pleasing appearance of the little craft that can beproduced in this way. A bow and stern block to raise the deck are cutout and nailed in place, as shown. A cabin is also placed on the sternof the craft, and this is formed by a block with a piece of cigar-boxwood placed on the top. The cigar-box wood should project a little overthe edges to form a canopy. The center of the deck can be raised by athird block; and three independent blocks, two large ones and a smallone, form the main cabin. Sandwiched in between these blocks are threepieces of cigar-box wood. The remaining details of the craft are sosimple that they may easily be made by following the diagram. 

[Illustration: FIG. 29]

Let us turn our attention to model war-ships. A torpedo-boat destroyeris clearly illustrated in Figs. 28 and 29. This is very simple toconstruct and makes a pleasing craft when finished. The hull is formedby two blocks. One of these forms the raised deck on the bow of theboat. The cabin is built up on this raised deck. It will be seen thatthe part of the hull that rests in the water is formed by one block. Inbuilding boats of this nature the constructor should be careful to keepthem long and slender, since torpedo-boat destroyers are always of thistype. They are high-speed craft, and their displacement must thereforebe as small as possible. Some of these boats carry four stacks and sometwo. The author prefers four stacks as giving the boat a betterappearance than two. The two little cabins near the stern of the boatare placed there merely to take away the plainness of construction. Theguns mounted forward and aft are merely round pieces of wood with apiece of wire bent around them and forced into a hole in the deck. 

[Illustration: FIG. 30]

The boat-builder should not be satisfied with one or two of these craft;he should make a whole fleet. This will afford the average boy a greatamount of pleasure, since he can add to his fleet from time to time andhave official launchings. Each boat can also be given a name and anumber. A little gray paint on the hull of these boats and black on thestacks gives them a very presentable appearance. 

[Illustration: FIG. 31]

[Illustration: FIG. 32]

A battleship is shown in Fig. 30. A battleship should be at least twiceas long as a torpedo-boat destroyer. A view of the battleship as it willlook in the water is shown in Fig. 31. By carefully examining thisdrawing the builder will be able to see just the number and shape ofthe blocks that enter into the construction of the craft. The battleshipis provided with four main batteries mounted in turrets, one forward andthree aft. A mast is also built, and strings run from it to the top ofthe main cabin and to the end of one of the turrets mounted aft. A screwis placed through the centers of the fore and aft turrets, so they canbe turned to any position. Battleships should be painted gray. It willbe necessary to place rather a heavy keel on the boat just described inorder to bring it down to the proper depth in the water. Otherwise itwill be topheavy and will capsize very easily. A fleet of battleshipsand battle-cruisers can easily be made according to the foregoinginstructions, and the builder should not be satisfied with producingonly one. 

A pleasure yacht is illustrated in Fig. 32. The hull of this craft isformed by two boards nailed together. The cabins are very simple, beingformed by a solid block of wood with a piece of cigar-box wood tacked tothe top. The windows and doors are marked in place with a softlead-pencil, and the stack is mounted midway between the two cabins. Awireless antenna should be placed on the boat, with a few guy-wires fromthe masts run to various parts of the deck. A lead-in wire also runsdown into one of the cabins. The hull of this boat should be paintedpure white. The deck can be left its natural color, while the stackshould be painted black and the cabins white with green trimmings. 

Almost any type of boat can be produced by the use of simple blocks ofwood and other miscellaneous pieces easily brought to shape fromordinary materials. This method of construction offers a wonderfulopportunity for the boy to exercise his creative faculties. 

CHAPTER IV

STEAM AND ELECTRIC PROPULSION

BOATS are propelled by two different systems. Some inland-water boatsstill employ side paddle-wheels, while ocean-going vessels use the moremodern propeller or screw. 

The paddle-wheel really acts as a continuous oar. Such a wheel is shownin Fig. 33. As the wheel goes around the paddle dips into the water andpushes the boat forward. If the direction of the boat is to be reversed, the rotation of the paddle-wheels is reversed. 

[Illustration: FIG. 33]

[Illustration: FIG. 34]

[Illustration: FIG. 35]

[Illustration: FIG. 36]

[Illustration: FIG. 37]

[Illustration: FIG. 38]

Before passing onto the screw, it may be well to explain just how apaddle-wheel causes a boat to move. When a man gets into a rowboat, hegenerally pushes himself off by placing his oar against the dock orshore and pushing on it. That is just what the paddle does in the water. It dips into the water and pushes against it. It must be remembered, however, that water is unlike a solid substance and it "gives. " When aman places his oar against the bank and pushes it, the bank does notmove, and all of the man's energy is used in starting the boat. Water, however, does not remain stationary when the paddles push against it, and therefore all of the power it not utilized in moving the boat--partis used in moving the water. 

The paddle-wheel is not so efficient in moving a boat as the more modernpropeller--or screw, as it is more often called. The screw receives itsname from the ordinary metal screw, because its theory of operation isexactly the same. A wood screw, when turned, forces itself into wood. Apropeller, when turned, forces itself (and thereby the boat) through thewater. A small propeller is illustrated in Fig. 34. This is an ordinarythree-blade propeller. (The writer prefers the word propeller instead ofscrew. )

From the drawing, it will be seen that the propeller-blades are mountedat an angle. This angle of the blades causes them to force water back asthey cut through it when the propeller is revolving. This forcing of thewater back tends to produce a forward motion of the propeller, and inthis way the boat on which the propeller is mounted moves through thewater. The propeller is caused to revolve by a steam-engine, steam-turbine, or gasolene-engine, as shown in Fig. 35. Longer boatshave more than one propeller. A boat that has two propellers is called atwin-screw boat. A boat driven with four propellers is called aquadruple-screw boat. 

When a machine screw is turned around just once, it moves forward acertain distance, as a glance at Fig. 36 will show. The distance thescrew moves forward will depend entirely upon the distance between thethreads. The distance between the threads is called the pitch of thethread. If the threads are 1/32 inch apart, then the screw will move1/32 inch every time it revolves. 

If a propeller acts in the same way as a screw, then it too must have apitch. The pitch, or the distance that a propeller will advance in onerevolution, is measured in inches. A propeller with a pitch of teninches should move ten inches through the water at each revolution. However, there is a certain amount of "slip, " and a propeller does notactually advance the distance that it should theoretically. The pitch ofa propeller is really the distance it would advance in one revolutionif it were revolving in an unyielding or solid substance. 

To make a simple propeller, first cut out of thin sheet brass threeblades as shown at _A_, Fig. 37. Sheet brass with a thickness of 1/32inch is very suitable for this purpose. Next, a block, as shown at _B_, is carefully carved out so that the propeller can be hammered down intothe depression. The same block is used for the three blades, so thateach will have the same curvature. The block should be cut from oak, since this wood will not split or lose its shape when the forming isdone. 

The hub is made next. This is shown at _C_, Fig. 37. The hub, of brass, is made according to the stream-line method. It is filed to shape from apiece of round brass stock. A hole runs lengthwise in the brass, asshown, and a set-screw is used to hold the hub of the propeller-shaft. The method of cutting the slots in the hub is shown at _D_, Fig. 37. Thehub is clamped between two boards placed in the vise, and a hacksaw isused to cut a slot in the hub. The hub is then turned around one thirdof a revolution, and another slot cut, using the same saw-marks in theboards, so that the angle of the second slot will be the same as thefirst one. The third slot is cut in the same manner. The three bladesthat were cut out are now fastened in these slots and held there bysolder. This completes the propeller and it is now ready to be fastenedupon the propeller-shaft. 

Let us consider the general method of putting the propeller-shaft inplace. The young boat-builder will readily understand that it would bevery impractical merely to bore a hole in the hull of the boat to putthe propeller-shaft through. In this way water would surely leak intothe hull and the boat would sink in a short time. Some method must beevolved to keep the water out of the hull, and yet allow thepropeller-shaft to revolve freely. 

The propeller-shaft is arranged within a brass tube, as shown at Fig. 38. The brass tube should be about 1/8 inch larger in diameter than thepropeller-shaft. A little brass bushing must also be arranged at eachend, as shown. When the propeller-shaft is mounted in place in thetube, there will be a space between it and the tube. Before thepropeller-shaft is put in place it is well smeared with vaseline, andwhen it is placed in the tube the space between the shaft and the tubewill be completely filled with it. This will prevent water fromentering. Owing to the fact that vaseline is a soft, greasy substance, it will not prevent the rotation of the propeller-shaft. The brass tubeis placed through a hole bored in the hull of the boat. The hole shouldbe a trifle smaller than the diameter of the brass tube, so that thetube can be forced into the hole. 

[Illustration: FIG. 39]

[Illustration: FIG. 40]

[Illustration: FIG. 42]

One of the simplest methods of propelling a boat is by means of rubberbands. Such a boat is shown in Fig. 39. This is a small wooden hullfitted with a two-blade propeller. The propeller is shown at Fig. 40. Itis cut in a single piece and held to the propeller-shaft merely by adrop of solder since there will not be much strain upon it owing to thelow power of the rubber-band motor. The opposite end of thepropeller-shaft is bent into a hook, and the rubber bands run from thisto another hook placed at the bow of the boat. The rubber bands may besimilar to those employed by model airplane builders. The motor, ofcourse, must be wound up by turning the propeller around until the bandsbecome twisted into little knots, as shown at Fig. 39. Boats driven byrubber bands cannot be very large unless a great number of rubber bandsare used. Even then the power is short-lived. However, building a fewsmall boats driven by rubber-band motors will do much to teach theyoung boat-builder some valuable lessons in boat construction. 

Probably the best method of propelling model boats is the electricmethod. By building a boat large enough to accommodate two dry batteriesor a small storage battery and a little power motor, a very reliablemethod of propulsion is made possible. The boat must have sufficientdisplacement to accommodate the weight of the dry-cells and storagebattery. A boat two feet long, with a beam of 4-1/2 inches, is largeenough to accommodate one dry-cell and a small motor, providing thefittings of the boat are not too heavy. 

A suitable power motor for small boats, which will run with either oneor two dry-cells, is shown in Fig. 41. The connections for the motor aregiven clearly in Fig. 42, and a suitable switch to control the motor isshown at Fig. 43. 

Owing to its greater power, the storage battery is to be preferred. Dry-cells are extremely heavy and occupy considerable space. They arealso costly, since they do not last long and cannot be worked too hardunless they polarize. 

[Illustration: FIG. 41]

[Illustration: FIG. 44]

[Illustration: FIG. 43]

[Illustration: FIG. 45]

A very suitable method of mounting an electric motor is illustrated inFigs. 44 and 45. It will be noticed that the motor is inverted. A smallpinion or gear is mounted upon the armature-shaft of the motor. A largergear (about three times the diameter of the small one) is placed uponthe propeller-shaft. This gives a speed reduction of three to one. Itwill be seen that the propeller-tube is strapped within a strip of brassto a small cross-piece nailed to the bottom board of the hull. The hullis of the built-up type, and the other three boards that go to make itup are not shown. When the three boards are glued in place, a brassstrip is run across the top board and the base of the motor is screwedto this. This holds the motor rigidly in place so that it will not movewhen the power is turned on. The brass strip used should have sufficientthickness to hold the motor rigid. It will also be seen that the motoris tipped slightly so that it will come in line with thepropeller-shaft. 

[Illustration: FIG. 46]

[Illustration: FIG. 47]

[Illustration: FIG. 48]

It is not always possible to obtain small gears. For this reason themodel boat builder may find it necessary to use a different method offastening the propeller-shaft to the motor. A very good method of doingthis is shown in Fig. 46. Here a coiled wire spring is used. This iswound to shape on a rod, and a drop of solder holds it to the propellerand motor shafts. In the method of propulsion shown in Fig. 44 thearmature-shaft of the motor must be perfectly in line with thepropeller-shaft, or the gears will bind and unsatisfactory operation ofthe motor will result. With the little spring the motor will not have tobe mounted exactly in line with the shaft, and it will also be possibleto mount the motor standing up. Of course, if the motor is mounted inthis way it will be necessary to make the propeller-shaft longer, as isshown in Fig. 47. 

Still another method of driving the propeller is illustrated in Fig. 48. This method is so simple that the author feels explanation to beunnecessary. 

Clockwork can often be employed for propulsion purposes, but this methodis not very satisfactory. It is also very difficult to obtain suitableclockworks to install in a boat. Oftentimes it will be possible tosalvage the works of an old alarm-clock, providing the main-spring isintact. It is a very easy matter to mount the clock-spring and connectit to the propeller. Any one of the aforementioned methods can beemployed. 

Steam propulsion has its advantages; but, on the other hand, the writeris not inclined to recommend it as strongly as the electric method forreliability. Of course, steam is a more powerful agency in thepropulsion of small boats and thereby greater speed is attainable by itsuse. 

[Illustration: FIG. 49]

[Illustration: FIG. 50]

[Illustration: FIG. 51]

Here is a very simple small power plant suitable for driving boats up to3-1/2 feet in length. The boiler is shown in Figs. 49 and 50. The methodof assembling the boiler is pictured clearly in Fig. 49. A brass orcopper tube about 2-1/2 inches in diameter is used. Two end pieces arecut to shape and forced into the boiler ends. A hole is drilled in thecenter of these pieces before they are put in place. After the endpieces are forced in place solder is carefully flowed around theiredges. The brass rod is then threaded at each end and placedconcentrically within the boiler, as shown in Fig. 49. A nut is placedon each end of this rod and tightened. The nut is then soldered inplace. This brass rod, called a stay-rod, prevents the end of the boilerfrom blowing out when the steam pressure has reached its maximum value. Three holes are drilled in the brass tube, as shown. One is toaccommodate the steam feed-pipe that goes to the engine; another is forthe safety-valve, and still another for the filling plug. Thesafety-valve and filling plug are both shown in Fig. 51. The littlespring on the safety-valve is adjustable, so that the valve can beregulated in order to prevent it from blowing off at pressures lowerthan that at which the engine operates. 

[Illustration: FIG. 52]

A suitable firebox for the boiler is shown clearly in Fig. 52. This iscut to shape from stovepipe iron and held together with small rivets. Holes should be punched or drilled in the side of the firebox to givethe burner a sufficient supply of air. The burner is illustratedclearly in Fig. 52. The fuel-tank can be made from an ordinary tin canwith the cover soldered on, and a hole made for a cork by means of whichit is filled with denatured alcohol. A little pipe runs from thefuel-tank to the burner. It is advisable, if possible, to place a smallvalve in this pipe to cut off the fuel supply when necessary. The onlyother method of putting the burner out would be to stand it on its end. The burner consists of a rectangular tin box with a top cut out asillustrated. A piece of brass or copper gauze is placed in the top. Asbestos wool is used to fill the can, and the alcohol is drawn into thewool by capillary attraction, where it burns with a steady hot flame atthe surface of the copper gauze. In the corner of the can near thefeed-pipe another small piece of copper gauze is soldered as shown. Thiscovers up the feed-pipe entrance so that the asbestos will not plug upthe pipe. 

[Illustration: FIG. 53]

[Illustration: FIG. 54]

The engine to be used in connection with the boiler just described isshown in Fig. 53. This is a very simple engine of the oscillation type, and there should be little trouble in making it. A more mechanicaldrawing of the engine is shown in Fig. 54. The details of the engine areshown in Fig. 55. 

[Illustration: FIG. 55]

The cylinder of the engine should be made first. This is made from apiece of brass tubing with an internal diameter of 3/4 inch. Two endpieces, or a cylinder-end cover and cylinder head, must be cut to fitinside the cylinder. These should be cut to shape from 1/16 inch brass, and a hole drilled in the cylinder head 1/8 inch in diameter toaccommodate the piston-rod. The cylinder head is then soldered in place. The cylinder-end cover should be left until the piston-rod and pistonare made. 

The piston head is cut to shape from a piece of 3/16-inch sheet brass, or it can be cut from a piece of 3/4-inch round brass with a hacksaw. The piston-rod is soldered into a hole in the piston-head. A smallsquare piece of brass is placed on the opposite end of the piston-rod toact as a bearing. This little piece is cut and drilled as shown in thedrawing. Before it is soldered in place on the piston-rod thecylinder-end cover should be placed on the rod. Both the piston and thecylinder-end cover can then be placed inside the cylinder, and thepiston-end cover is soldered in place. Before final assembling thepiston should be made to fit nicely into the cylinder. This can bebrought about by applying emery cloth to the piston-head until it slipsnicely into the cylinder with little or no play. Thus a steam-tight fitis made, and this contributes greatly to the efficiency and power of theengine. 

[Illustration: FIG. 56]

[Illustration: FIG. 57]

The cylinder blocks are shown in Fig. 55. These are cut and brought toshape with a hacksaw and file. With a half-round file one side of one ofthe blocks is filed slightly concave, so that it will fit on the outsideof the cylinder. Two 1/8-inch holes are drilled in this piece as shownin the drawing. The hole at the top is the steam entrance and exhaustfor the engine; that is, when the cylinder is at one side steam entersthis hole, and when the crank throws the cylinder over to the other sidesteam leaves through the same hole after having expanded in thecylinder. This cylinder block is soldered to the piston as shown inFig. 56. The pivot upon which the cylinder swings is then put in placein the hole at the bottom of the block. Solder is flowed around thepivot to hold it securely in place. 

The second cylinder block is now finished according to the drawing. Thishas two holes 1/8 inch in diameter bored in it. One of these holes isthe steam inlet and the other the exhaust. When the cylinder is at oneside of its stroke the hole that was bored in the top of the steam blockwhich was soldered on the cylinder is in line with the inlet hole in theblock under consideration. Steam then enters the cylinder and forces thepiston down. This turns the crank around, and the crank in turn pullsthe piston over to the opposite side, so that the hole in the firstpiston block of the cylinder now comes in line with the exhaust hole onthe second cylinder block. The steam in the cylinder escapes and thesame operation is repeated over again. Of course, it must be understoodthat this steam admission and exhaust takes place very rapidly. The holein the second cylinder block, which goes over the pivot, must be made atrifle more than 1/8 inch in diameter, so that it will slide freely overthe pivot. 

The engine is mounted on a very simple frame, which is a piece of1/16-inch brass cut and bent as illustrated. After it is cut and bent toshape the second cylinder block is soldered in place. The cylinder canthen be mounted. It will be seen that the pivot goes through both thesecond cylinder block and the engine standard. A small spring is placedover the protruding end of the pivot and a nut put in place. By turningthis nut the pressure on the face of the two cylinder blocks can beadjusted, and the model engineer must always remember that the pressureon these springs must be greater than the steam pressure in thefeed-pipe. Otherwise the steam pressure will force the cylinder-blockfaces apart and steam leakage will result. On the other hand, thepressure of the spring should not be too great, since that wouldinterfere with the free movement of the engine cylinder. 

Nothing now remains to be made except the crank and the flywheel. Thecrank revolves in a small brass bearing which is soldered in place onthe engine standard. It will be seen that the sheet brass that makes upthe engine standard is not thick enough to offer a good bearing for thecrank. The crank is bent to shape from a piece of 1/8-inch brass rod, and the author advises the builder to heat the brass rod red-hot whilethe bending is done. This will prevent it from fracturing, and will alsopermit a sharp bend to be made. 

The flywheel is a circular piece of brass 1 inch in diameter. Its centeris drilled out and it is soldered to the crank as illustrated in Fig. 54. Two other holes 1/8 inch in diameter are drilled in the flywheel asillustrated, and two small brass pins are cut out from 1/8-inch brassrod and forced into these holes and then soldered. These provide amethod of driving the propeller-shaft that is shown very clearly at Fig. 57. 

The steam feed-pipe that runs from the boiler to the engine can be ofsmall copper tubing. It may be necessary to mount the engine on a smallblock, as shown in Fig. 53. After the steam in the boiler has reached asufficient pressure the engine crank should be given a couple of twistsin order to start it. Before operating the engine a little lubricatingoil should be run into the cylinder through the inlet or exhaust ports. The cylinder should always be kept well lubricated. The contacting facesof the cylinder blocks should also be kept lubricated. 

_Caution. _ Always keep water in the boiler. Never permit it to run dry, as this would cause a boiler explosion. When the engine is started andcannot be made to run, take the burner from under the boiler so thatsteam will cease to be generated. With the safety-valve the model boatbuilder need have little fear of an explosion. Nevertheless theforegoing directions should be carefully adhered to. 

CHAPTER V

AN ELECTRIC LAUNCH

THE little electric launch to be described is of very simpleconstruction, and when finished it will provide the builder with a veryshipshape little model from which he will be able to derive a good dealof pleasure. It has a speed of from 2-1/2 to 3 miles an hour whenequipped with dry batteries or storage batteries. The hull is of theSharpie type, and this offers very little trouble in cutting out andassembling. 

The general appearance of the boat and hull will be gathered from thedrawings. The pieces necessary to assemble the hull are shown in Fig. 58. Only five pieces are necessary: two side pieces, a stern piece, abow piece, and a bottom piece. The length of the boat over all is 40inches with a 7-inch beam. The widest part of the boat is 1 foot 10inches from the bow. 

After the pieces that form the hull are cut they are thoroughlysandpapered to produce a smooth surface. The heavy imperfections in thewood can be taken out with coarse paper, and the finishing can be donewith a finer paper. It is understood that sandpapering should always bedone with the grain, never across the grain. The sides of the boat arecut about 1/4 inch thick, but they are planed thinner in places wherethe bend is most pronounced. The side pieces are 2-3/4 inches deep atthe stern and 2-1/4 inches at the stern. There is a gradual curve fromthe bow to the stern, which is more marked toward the head. 

The stern piece is thicker than the side pieces, being made of 1/2-inchwood. It is cut to the shape shown at Fig. 58, and beveled along thebottom edge to enable it to be fixed on the slant. The bow piece is atriangle 2-3/4 inches in length. 

After the parts are thoroughly finished with sandpaper the stern pieceis fixed in position. In making all the joints on the boat the buildershould see that plenty of fairly thick paint is run in while the jointis being screwed up. This will help greatly in making the boatwater-tight. Plenty of 3/4-inch brass wood-screws are used in assemblingthe hull. All the holes for the wood-screws should be countersunk sothat the heads will come flush with the surface of the hull. Now one ofthe sides should be screwed to the stern piece, at the same time bendingthe bottom and side to meet. This is done gradually, inch by inch, andscrews are put in place at equal distances. When the bow is reached, theside piece is beveled to fit the bow piece, which should already havebeen screwed into place. The other side of the boat is treated in asimilar manner, and the young worker should take care to keep the sideand bow piece perfectly square and upright. This may sound easy onpaper, but it will be found that a good deal of care must be exercisedto produce this result. 

After the hull has been assembled it is given a good coat of paintinside and out. When the first coat is dry the holes left by thescrew-heads are carefully puttied over, and the hull is given a secondcoat of paint. This procedure will produce a perfectly water-tighthull. 

[Illustration: FIG. 58]

[Illustration: FIG. 59]

[Illustration: FIG. 63]

The stern tube is 3/8 inch, outside diameter. A hole is bored in thebottom of the boat to receive the stern tube. This job must be donecautiously; otherwise the bottom of the boat may be ruined. It is bestto screw a substantial block to the inside of the boat. This blockshould be cut to fit the bottom and will act as a support for drilling. It will also help greatly to make a water-tight joint around the tube. The distance from the point where the stern tube passes through thebottom to the stern should be about 12-1/2 inches. The stern tube shouldbe mounted as nearly parallel with the bottom as possible, since on thisdepends the speed of the boat. As the angle of the propeller-shaftincreases, the speed of the boat will decrease. In drilling the hole theboat-builder should be careful to keep the drill running along thecentral line of the boat. 

As before mentioned, the stern tube is a piece of brass tubing 3/8 inchin diameter and 8 inches long. It is filed square at both ends, and abrass plug is fastened with solder in each end. The tube is then filledwith melted vaseline, which is allowed to cool. The hole in the hullaround the tube is then well smeared with thick paint. When this isdone, a layer of red lead or putty is placed around the joint both onthe inside and the outside of the boat. 

While the putty is drying the spray-hood or turtle-deck can be made. This is bent to shape from a piece of tinplate and extends half waydown the boat. When the turtle-deck is finished, it is best to lay itaside, before finally fastening it in place, until the entire boat iscompleted. 

The wooden part of the deck is made of 1/8-inch wood and scribed with asharp knife to represent planking. This method of producing planking wasdescribed in detail in Chapter II. 

Toward the stern of the boat and just behind the motor a hatchway isfitted to give access to the batteries and starting switch. 

The finished Sharpie hull without its driving batteries or motor shouldweigh about 1 pound 3 ounces. The hull being finished, let us considerthe electric propelling equipment. 

A 1/8-inch cold-rolled steel driving or propeller-shaft is used. Theshaft is 13 inches long and a gear-wheel 1 inch in diameter is fixed toone end of this shaft. This gear-wheel meshes with a brass pinion on themotor-shaft. This forms a 3-1/2 to 1 reduction gear, which produces agreatly increased speed of the boat. The other end of thepropeller-shaft rests in the skeg bearing. In this present case thisconsists of a tube about 1/2 inch long, which is made for a revolvingfit on the propeller-shaft and supported by a sheet-metal bracket. Thisis shown in Fig. 63. The end of the propeller also revolves adjacent tothe bearing in the skeg. 

[Illustration: ©_Jack Sussman_

GETTING READY FOR A TRIP

Heating the blow-torch to a point where it will burn automatically]

The propeller is a three-blade affair with a diameter of 2-1/4 inches. It is attached to the propeller-shaft with a set-screw. The motor is avery simple type obtainable in the open market. It is similar to oneshown in Fig. 41. As before mentioned, either dry or storage batteriesmay be used as a source of current. The writer strongly advises the useof storage batteries if possible. The initial cost of these batteries isgreater than that for dry batteries; but, on the other hand, the smallstorage battery can be charged repeatedly and will outlast many drybatteries. If the boat is used much the storage battery will probably bethe more economical of the two. 

The steering gear of the boat is very simple. The rudder works in abearing that is screwed to the stern piece. The end of the rudder-shaftis tapped, and a brass screw is used to clamp it in position aftersetting it with the fingers. The rudder-shaft is a 3/4-inch brass rod. The lower end of this rod is slit with a hacksaw and the rudder isplaced in this. Solder is then flowed along the joint. 

[Illustration: ©_Jack Sussman_

ALL READY TO GO!

A little boat with steam up, ready for a trip when her owner releasesher]

[Illustration: FIG. 60]

Of course, the builder may paint his boat whatever color he may select;but a maroon hull with a white-enameled spray-hood or turtle-deck makesa very pleasing combination. Fig. 60 shows a rough plan of the generalarrangement of the power machinery. Figs. 61, 62 and 63 will do much togive the reader a clear idea of the method of construction which couldnot be gained by reading a description. 

[Illustration: FIG. 61]

The general appearance of the boat can be improved materially in manyways. For instance, a little stack or ventilator may be added to theturtle-deck, and a little flag-stick carrying a tiny flag may be placedon the bow and on the stern. 

[Illustration: FIG. 62]

The motor current should be turned on only when necessary, for dry-cellsdeteriorate rapidly when in use, and small storage batteries quicklylose their charge, although they will last much longer than dry-cellsand give much better service. 

CHAPTER VI

A STEAM LAUNCH

THE steam launch _Nancy Lee_ is an attractive little craft when finishedand it is capable of attaining considerable speed. It is really designedafter the cruising type of motor-boats. This type of boat isparticularly adaptable for simple model-making, owing to the eliminationof awkward fittings. The power machinery is of very simple constructionand presents no real difficulty. 

The following materials are necessary to construct the _Nancy Lee_:

 Large wood block for hull. Thin white pine for deck, etc. Sheet-metal tube, rod and wire for the boiler, engine, etc. Lamp-wick, paint, screws, and brads Miscellaneous fittings

The actual expense necessary to construct the boat is very small. 

Having obtained the block for the hull, you are ready to start work. Thehull, when planed on all sides, should be 30 inches long, 6-1/2 incheswide, and 3-3/4 inches deep. A center line is drawn down the length ofthe hull, and five cross-section lines are drawn at right angles to thecenter line 5 inches apart. On these lines the builder should mark offthe greatest lengths of the boat, taking the dimensions from thehalf-breadth drawing shown in Fig. 64. It will be noted that the deck iswider than the L. W. L. Forward and narrower than the L. W. L. At thestern. The block should be cut to the widest line on the half-breadthpart. 

[Illustration: FIG. 65]

[Illustration: FIG. 67]

[Illustration: FIG. 64]

The half-widths in Fig. 64 are drawn each side of the center line on theblock. The block will be cut out to this line and planed up as true aspossible. The builder should then project the section lines with a setsquare on each side of the boat, mark off the profile from the sheerplan, Fig. 65, and cut the block to this line, afterward planing it uptrue. 

[Illustration: FIG. 66]

The blocks should now appear as sketched in Fig. 66. It is now ready forthe shaping of its exterior. A plane, a chisel, and a draw-knife are theonly tools necessary to bring the hull to the correct shape. Thecardboard templates must be cut, one for each half-section, as shown inthe body plan, Fig. 67. These templates serve to show the proper outsideshape of the hull. The block for the hull must be cut away until eachone of these templates fits properly into place. The various stages areindicated in Figs. 68 and 69. 

[Illustration: FIG. 68]

The interior of the board is gouged out with a gouging chisel, and ifthe builder desires a uniform result he should make inside templates. Ingouging out the interior of the hull the chisel or gouge should behandled very carefully; otherwise it is liable to slip and spoil theentire hull. 

[Illustration: FIG. 69]

The next job is to cut and properly fit the raised portion orforecastle. A piece of wood 1-1/4 inches thick, 15 inches long, and6-1/4 inches wide must be prepared and laid in place on the hull. Theshape of the hull is marked off with a pencil and the wood sawed alongthis line. The inner portion is also cut out, thus making a V-shapedpiece which must be glued and screwed in place, as shown in Fig. 70. 

[Illustration: FIG. 71]

[Illustration: FIG. 70]

The oval air-vents shown in the drawing can be cut at this time. Thehull is neatly finished by cutting in the sheer or curvature of the hulland sandpapering it all over. A cross-beam or support, _C_, Fig. 70, iscut and fitted as illustrated. This particular piece supports thefore-deck, and also carries the main-deck, as well as bracing the boattogether. This piece should be 3/16 inch thick and cut from solid oak. 

The decks can be made of a good quality of white pine. The buildershould select clean pieces, free from knots and blemishes. It onlyrequires to be cut to shape and then fixed to the hull with a few brads. The edge should be cleaned up flush with the hull by the aid of a plane. The opening for the cock-pit, shown in the drawing in Fig. 71, is to becut in the deck. The coamings and seats are cut to the sizes indicatedin the drawings. They are then glued and pinned together. When fitted tothe deck the result will be somewhat as shown in Fig. 71. 

The fore-deck is prepared in a similar manner; but, since this is to beremovable, two battens must be fitted to the under side to keep it inplace. The openings for the hatchways can be cut and the hatch-coversmade by cutting another piece of wood 3/16 inch thick to form an edging. A cover piece to go over the small pieces, removed from cutting out thehatch opening, is shown at Fig. 72. A coping-saw will be found veryuseful for this work. The covers are neatly rounded on the edge andnicely finished. 

[Illustration: FIG. 72]

[Illustration: FIG. 73]

[Illustration: FIG. 74]

[Illustration: FIG. 76]

Fig. 73 will give the reader a very good idea of the appearance of theboat at this stage. It will be seen that the sketch shows the deckbroken away so as to render the cross-batten visible, which also showsthe fair-lead at _F_, Fig. 73. This is cut from two small pieces of3/16-inch stuff, glued and pinned in place. The forward deck iscompleted by the addition of cowl-ventilators, cut from hard wood andscrewed in place. The flag-mast is made from a short piece of 1/16-inchwire. The details of the mooring-cleats are shown in Fig. 74. They arefashioned by using a small screw-eye and soldering a short piece ofbrass wire through the eye. An oblong metal plate is then cut and acentral hole drilled. This plate is soldered to the shank of thescrew-eye and the cleat is complete. One of these devices is to befitted to the fore-deck and two on the main-deck and stern. 

[Illustration: FIG. 75]

The rudder and steering gear will be considered next. Fig. 75 shows thestern of the boat with the rudder gear mounted in place. It will benoted that the rudder-blade is merely a piece of sheet brass cut toshape and soldered into the rudder-post _M_, which is slit toaccommodate it. The rudder-post is hung in two screw-eyes on the sternof the boat. A small wheel about 1 inch in diameter, with an edge filedin it, is soldered to the top of the rudder-post. A fine cord or string, well stretched and oiled, is attached to the wheel and led through twoscrew-eyes on the deck. From this it is led through an opening in thecoaming to a drum on the steering column, which is turned by anothersmall wheel similar to that used on the rudder-post, but with a roundedge. The steering column is merely a piece of 1/8-inch wire, held inplace by two small screw-eyes fixed in the coaming and with a tube-brushsoldered on to keep the wire in position. The drum is simply a hard-woodbushing driven tightly in place. 

The power machinery for the _Nancy Lee_ must be considered at this time. This is really one of the most interesting parts of the construction. The general appearance of the power plant can be seen by referring toFig. 77, which is a view of the complete boiler and engine mountedtogether on the same base. The boiler is shown at _A_ and thesafety-valve and filler at _L_. The base or firebox _B_ protects theburner from stray drafts of air, and also supports the boiler. 

The lamp or burner consists of a receptacle _C_ for containing thedenatured alcohol. The denatured alcohol is inserted through thefiller-tube _E_, which is kept closed with a cork. The upright tube _D_is fitted so that air can go into the receptacle containing the alcohol. Three burners are necessary to fire the boiler. These are fitted asshown in _F_, and they give sufficient heat to produce steam enough todrive the cylinder _G_. The steam is conducted to the cylinder throughthe short pipe _K_. The steam-cylinder has the usual piston and rod, which drives the circular crank _H_. This crank is mounted on acrankshaft carried on the metal tube _M_. As will be noticed, thecylinder is of the simple oscillating type mounted on a standard, formedas part of the boiler casing, and stiffened by two angle-plates _L_. 

A heavy flywheel, _J_, is now fitted to the inside end of thecrankshaft. This wheel should be a lead casting, and as heavy aspossible. A heavy flywheel contributes much to the operating efficiencyof the engine. The propeller-shaft and crank are shown at _N_ in theinsert. 

The boiler is made from a strong tin can about 1-3/4 inches in diameterand 4-1/2 inches long. It is cleaned inside and out, and all the seamsare double-soldered. The lid is also soldered on the can. This littleboiler, although not elaborately made, will be found capable of standingup under considerable steam-pressure, and so no fear need be had ofaccidents by explosion. 

[Illustration: FIG. 83]

[Illustration: FIG. 78]

[Illustration: FIG. 77]

[Illustration: FIG. 79]

[Illustration: FIG. 80]

[Illustration: FIG. 81]

[Illustration: FIG. 82]

A little safety-valve and filler-plug suitable for use on the boilerare shown clearly in Fig. 78. A piece of sheet tin is cut out to thesize and shape illustrated in Fig. 79 at _A_. The piece is bent up atthe dotted lines and the seams are soldered. Two angle-plates, _B_, arethen cut and fitted and soldered in place. Next a piece of brass tubewith a 1/8-inch bore and 1 inch long is cut and soldered in place forthe bearing of the crankshaft. A lead flywheel 1-1/4 inches in diameterand 1/2 inch thick is then mounted firmly on a piece of straight steelwire 1-3/4 inches long, which acts as a shaft. 

The shaft is made to run freely in the crankshaft bearing that waspreviously soldered in place. The cylinder is shown in section in Fig. 80. If the reader will refer back to the construction of the enginedescribed in Chapter 4 he will readily understand the operation andconstruction of this particular engine. 

A little crank must be cut from 1/16-inch brass, and soldered to thecrankshaft after fitting a wire crank-pin to the outer edge. Thiscrank-pin should be of such a size that the joint on the end of thepiston-rod shown at _A_, Fig. 80, turns on it easily. The throw shouldbe only half the stroke of the engine, which is 3/8 of an inch. 

The boiler is now fixed in place by bending the lugs _B_, Fig. 79, sothat they just support the boiler nicely. They are then soldered inplace. Next fit the short steam-pipe _K_ between the boiler and thesteam block on the cylinder. The builder should take care to keep thesteam-pipe well up to the top of the boiler. 

The lamp should be built at this time. The container for the denaturedalcohol is made from a well soldered tin box of suitable size. It canalso be made by cutting a sheet of tin to the size and shape shown inFig. 81. The corner joints are soldered and then a tin lid is solderedin place. The builder should not forget to make the filler-tube _E_ andair-tube _D_, as shown in Fig. 77, before soldering the top piece inplace. The burners should be made as high as the container, and theseshould be made from little pieces of tin bent to shape and soldered onto a bottom pipe, as shown in Fig. 77. The builder should also rememberto cut the holes through this pipe so that the alcohol can get into theburner-tubes, and also to solder the open end of the bottom or feedtube. Before the wicks are put into the lamps, the container should betested by filling it with alcohol to see that it is perfectly tight atall joints. If it is not the container should be gone over again withsolder to assure its being leak-proof. 

Before operating the engine with steam, it can be tested with a smallbicycle pump through the opening for the safety-valve. The engine shouldturn over briskly at every stroke of the pump, providing it does notcome to rest at "dead center. " If it does come to rest at "dead center, "where no air can enter the piston, the crankshaft should be given alittle twist and the engine will then start. Before steam is applied itwill be well to experiment until the engine runs with the air-pump. 

Having made the engine run smoothly with air, steam can be generated inthe boiler. The wicks should not be placed too tightly in the burners. After they are in place the container may be filled with denaturedalcohol, and the burners lighted and placed under the boiler. In a veryfew minutes steam will be up. At the first indication of pressure in theboiler the engine should be given a twist with the fingers until itstarts and goes of its own accord. The constructor should remember tokeep his engine well lubricated. 

The propeller-shaft is merely a piece of steel wire, perfectly straightand fitted with a crank _A_, Fig. 82. This crank is similar to the onefitted to the engine, but with a small slot cut out for the crank-pin tofit into. This is done so that, as the crank-pin on the engine turnsaround, it also turns a slotted crank on the propeller-shaft. 

A short piece of tube, _C_, is now fitted to a flat brass plate, _D_. The plate is mounted at an angle to the tube, so that when it is inplace on the stern of the boat the propeller-shaft will be in line withthe crankshaft of the engine. 

A clearance hole is now drilled through the hull, so that thepropeller-shaft can be put in place. Solder the tube to the plate, andpunch four small holes in the plate, so that it can be screwed firmlyto the hull. Solder a short piece of tube, as shown at _B_, Fig. 82, tokeep the propeller-shaft in position. 

The propeller must now be made. This is easily done by cutting out adisk of brass 1-1/2 inches in diameter, as shown in Fig. 83. The shadedportions of the brass disk are cut away. The blades are bent to shape, care being taken to see that they are all alike. This done, thepropeller is soldered to the propeller-shaft. 

The only part of the job that remains is to screw the boiler in placeunder the fore-deck of the boat. This done, the _Nancy Lee_ is ready forher trial. The fore-deck should be made removable by fitting it withpins or screws with the heads cut off, so that the deck only needspushing into place. This little boat should be capable of attaining aspeed of from four to five miles an hour if it is made carefully andaccording to the directions outlined in this Chapter. 

CHAPTER VII

AN ELECTRICALLY DRIVEN LAKE FREIGHTER

A PROTOTYPE of the model lake freighter described in this Chapter willprobably be familiar to many readers. It is a type of boat used on theGreat Lakes, and, owing to its peculiarity of design, it lends itselfvery well to construction in model form. 

The lines of the boat may be seen very clearly in Fig. 84. 

The hull of the model freighter measures four feet over all, and thebeam at the water-line is 8 inches. The extreme draft will be in theneighborhood of 5 inches. This model, when completed, will be capable ofcarrying considerable weight; in fact, it is able to accommodatethirty-five pounds in weight when used in fresh water. This will givethe builder an opportunity to install a very substantial powerequipment with little regard for weight. 

[Illustration: FIG. 84]

[Illustration: FIG. 85]

The hull is made according to the built-up principle, and theconstructor will have to cut his templates before attempting the shapingof the hull. Owing to the depth of the model, it will be necessary touse about ten planks. The plank that is used to form the bottom of theboat is not gouged out. Every other plank is gouged out with a saw andchisel. 

The bottom plank is shaped with a knife to conform to the lines of theboat. In building up the hull with the planks, they should first besmeared with glue, and when put in place a few brass brads should bedriven in. As mentioned in an earlier part of this book, iron nailsshould not be used in work of this nature, owing to the fact that theywill rust and cause trouble. The brass brads are placed about one inchapart the entire length of the boards. The hull is finished with a planeand sandpaper, and after it has been brought to shape in this way andfinished, a coat of paint is applied. Black with dark red trimmingsmakes a very good combination for a boat of this type. 

The deck is made from a piece of 1/4-inch pine board. Seven hatches areadded to the deck. Six of these hatches can be made by merely gluing asquare piece of 1/4-inch wood to the deck. The seventh hatch should bemade with a hole cut in the deck, so that access can be had to the powermotor. 

The deck-house, wheel-house, and chart-house, as well as the bridge, should be constructed of tin, which may be salvaged from clean tincans. The bridge is provided with spray-cloths made from white adhesivetape, as outlined in Chapter 9. The port-holes in the deck-house andhull are made by little pieces of brass forced in place over a smallpiece of mica. The life-boats, which are carried on top of theengine-house, are whittled out of a solid piece of wood and paintedwhite. Life-boats are always painted white, regardless of the color ofthe boat upon which they are used. The life-boats are held by means ofstring and small dummy pulleys to davits made of heavy stovepipe wire. Arub-streak made of a piece of 1/4-inch square pine is tacked to eachside of the hull just below the sheer-line. The rub-streak should betacked in place with nails such as those used on cigar-boxes. 

The funnel measures 1 inch in diameter by 4 inches long. A small exhauststeam pipe, which can be made from a piece of brass tubing, is mounteddirectly aft of the funnel. The forward deck fittings consist mainly ofa steering-boom, two bollards, two fair-heads, and four life-buoysmounted on the bridge. The main-deck is equipped with six bollards andtwo covered ventilators, each 1/2 inch in diameter. The foremast isproperly stayed in the deck, and should be fitted with rat-lines. Therat-lines can be made with black thread and finished with varnish, whichwhen dry will tend to hold the threads in shape. 

The rudder is cut from a piece of sheet brass to the shape shown, andfitted with a quadrant. The engine cabin can be made from cigar-boxwood. The windows and doors can either be painted in place, or thewindows can be cut and backed up with sheet celluloid. A good substitutefor painted doors will be found in small pieces of tin painted adifferent color from the cabin. The same procedure may be followed infitting the windows and doors to the forward cabin. 

We are now ready to consider the power plant. Owing to the largedisplacement of the boat, it will carry a fairly heavy storage battery. The electric motor and storage battery are mounted in the manner shownin Fig. 85, which will also give the reader an idea of the appearance ofthe finished model. As the drawing indicates, it will not be necessaryto tilt the motor to any great degree in order to bring the propeller tothe proper depth. This is because of the depth of the boat. Instead of astring or belt to connect the motor with the propeller, the shaft of themotor is taken out and replaced by a longer steel rod that will serveboth as a motor-shaft and a propeller-shaft. The propeller-shaft extendsfrom the motor through the stern-tube. The propeller used for this modelis a three-blade affair, 3 inches in diameter. It must be of this sizein order to propel a boat of these dimensions at a consistent speed. 

Care must be taken in mounting the motor in this way. If it is notmounted directly in line with the stern-tube the propeller-shaft willhave a tendency to bind. However, with a little care no trouble shouldbe experienced from this source. The storage battery used should be ofthe four-volt forty-ampere hour variety. This boat will be capable ofcarrying such a battery and this weight should just bring the craft downto her load water-line. The whole deck is made removable, so that thestorage battery can be taken in and out at times when it is necessary torecharge it. A battery of this capacity, however, will drive a smallmotor similar to the type used on the boat for some time. 

CHAPTER VIII

AN ELECTRIC SUBMARINE-CHASER

THE submarine chaser design given in the drawings and described in thetext of this Chapter is a presentable little boat with pleasing linesand deck fittings. There is nothing difficult about its construction, and, considering the amount of work necessary to produce it, it isprobably one of the most pleasing boats described in the book. If madecorrectly it will look "speedy" and shipshape. 

The general outline of the boat can be gathered from Figs. 86, 87, and88. Fig. 86 gives a side view of the craft; Fig. 87 shows the bow, whileFig. 88 gives the deck-plan. 

[Illustration: FIG. 86]

[Illustration: FIG. 87]

[Illustration: FIG. 88]

Notice first the construction of the hull. This is made according to theSharpie type, but the lines are changed to give the boat a more gracefulappearance. This is done by changing the shape of the deck and thebottom pieces. Fig. 89 shows the various pieces necessary to constructthe hull. It will be seen that the forward portion of the bottom pieceis narrower than the deck piece, and broadens out so that it is wider atthe stern than the deck piece. The deck piece has a maximum width of 5inches, while the bottom piece has a width of 4 inches at the forwardsection. The deck measures 3-1/2 inches at the stern, while the bottompiece measures 4-1/2 inches at the stern. This produces a half-inchtaper on each side of the stern. A half-inch taper is also produced onthe bow portion. 

[Illustration: FIG. 90]

[Illustration: FIG. 91]

[Illustration: FIG. 89]

The hull of the boat can be made from 1/8-inch mahogany. If this is notavailable, choose some other close-grained wood, free from knots andblemishes. Paper patterns are made to correspond with the general shapeof the pieces that form the hull as given in Fig. 89. The pieces, afterbeing marked, are cut to shape with a keyhole-saw. After this is donetheir edges should be trimmed neatly with a jack-plane. 

The two sides pieces are now screwed to the bow piece by small brassscrews. After this is done the bottom piece is fastened to the sidepieces the entire length of the boat. Next the first cross-piece, asshown in Fig. 90, is screwed in place. This cross-piece should be 4-3/4inches in length, so that the width of the hull at this point is just 5inches. The next cross-piece should correspond to the width of the deckpiece at the section of the hull where it is placed. The same holds truefor the third cross-piece. When the third cross-piece has been screwedin place, the stern piece is put in position. 

The joints of the hull should then be smeared with either pitch orbath-tub enamel or a thick mixture of white lead may be used. 

After having made sure that the hull is perfectly water-tight the workercan proceed to install the power equipment. This consists of a smallbattery motor driven with two dry cells. The design and installation ofsuch things as stern-tubes and propeller-shafts have been taken up indetail in an earlier part of this book. The strut that holds thepropeller-shaft is shown in Fig. 91. This consists merely of a brassbushing held in a bracket made of a strip of brass 1/2 inch wide. Thebrass strip is wound around the bushing and soldered. It is held to thebottom of the hull by means of two 8-32 brass machine screws. Thesescrews should be tightened to prevent leakage. It would be inadvisableto use wood-screws for this purpose, owing to the fact that the bottompiece of the boat is thin. 

[Illustration: FIG. 93]

[Illustration: FIG. 92]

The two dry batteries for the motor are held in two tin troughs, asillustrated in Fig. 92. These troughs are fastened to the side of theboat by means of small bolts. They will prevent the boat from shiftingits cargo; in other words, they hold the batteries in place and therebyprevent the boat from listing. 

The deck and deck fittings should now be furnished. The construction ofthe forward cabin is shown in Fig. 93. The sides and back are formedwith cigar-box wood, while the curved front can best be made with apiece of tin. The top is also cut to shape from cigar-box wood, andshould overlap about 1/4 inch. The pilot-house is simplicity itself, being made of a piece of curved tin with three windows cut in it. Fourlittle lugs cut in the tin are bent on the inside and each provided witha hole. These lugs are used to tack the pilot-house to the deck. A smallskylight is produced from a solid piece of wood and tacked in place asillustrated in the drawing. 

The builder is cautioned not to destroy the appearance of his boat bymaking the mast too large. After the mast has been nicely sandpapered, alittle wire frame is bent to shape and fastened to the top, as shown inFig. 87. The little wire railing that is placed in front of the mast isthen bent to shape, and this and the mast are put in their permanentposition. The mast can be held to the deck by boring a hole a littleunder size and smearing the bottom of the mast with a little glue beforeit is forced in. Pieces of black thread are run from the top of the mastto the railing at the bottom, as shown. These threads are used to hoistsignal flags. Two little angle-pieces are placed on the forward deck, one on each side of the pilot-house. These are for the harbor lights. One should be painted green and one red. 

This finishes the forward cabin. It should be placed in the center ofthe deck and the position it occupies should be marked out with apencil. This portion of the deck should be carefully cut out with acoping-saw. The cabin is then forced into the opening. The fit should befairly tight, so that it will not be necessary to employ nails or glue, as this is the only way in which the interior of the hull is madeaccessible. 

Two ventilators are placed just back of the forward cabin. Between theforward cabin and the cabin aft there is placed a rapid-fire gun. Thedetails of this gun are given in Fig. 94. The barrel of the gun is madeof a piece of brass rod. A hole is drilled through this rod with a smalldrill and a piece of copper wire is inserted. A square piece of brassfor the breech is then drilled out to receive the barrel. One end of thebarrel is placed in this hole and held with a drop of solder. A drop ofsolder should also be used on the copper wire that runs through thebarrel. The bearing and shield of the gun are made from thin sheetbrass, as illustrated. Three holes are drilled in the bearing bracket, two through which the wire passes and one through which the small nailis placed to hold the bearing to the wooden standard. The shield isforced over the barrel and held in place with a drop of solder. When thebarrel is mounted in the bearing, a drop of solder should be put inplace to prevent the barrel of the gun from tipping. 

[Illustration: FIG. 94]

The cabin which is placed aft on the boat, is of very simpleconstruction. It is made up entirely of cigar-box wood tacked together, and the top should overlap 1/4 inch. The cabin is then tacked to thedeck of the boat. The mast should be only three-fourths as high as theforward mast, and a tiny hole is drilled near the top. Into this hole asmall piece of soft wire is placed, and from this wire a thread runs tothe cabin. A small flag can then be placed on the thread, as illustratedin Fig. 86. 

Six port-holes are now bored in each side of the hull with a 1/2-inchbit. These can be backed up with mica or celluloid. Five smallerport-holes made with a 1/4-inch drill are then bored in each side of theforward cabin. Three are placed in the aft cabin. 

With the exception of painting, the hull is now ready to be launched. Before finally applying the paint the hull should be given a thoroughrubbing with sandpaper. A battleship gray with maroon trimmings makes apleasing color combination for this boat. 

CHAPTER IX

BOAT FITTINGS

THE model boat builder generally has some trouble in producing thenecessary fittings for his boats. It is practically impossible to buysuch things in this country, and so it is necessary to make them. 

Using a little care, it is possible to make presentable fittings byutilizing odds and ends found about the household and shop. In thisChapter the author will describe the construction of the more importantfittings necessary to model boats, such as stacks, searchlights, bollards, cowl-ventilators, davits, and binnacles. 

The smokestack is probably one of the easiest things to produce. A verysuitable method of producing a smokestack is shown in Fig. 95. The stackitself is cut from a piece of thin brass tubing. It is also possible touse a small tin can of the proper diameter. In both cases, of course, paint must be applied to improve the appearance of the brass or tin. Ifthe stack is painted either gray or white a red band near the top of thestack produces a good finish and makes it look more shipshape. 

[Illustration: FIG. 95]

[Illustration: FIG. 97]

The method of anchoring the stack to the deck of the boat is shown veryclearly. First a block of wood is cut about the same diameter as theinternal diameter of the stack. This block of wood is then forced upinto the stack. A small square base is then cut, and fastened to theblock on the inside of the stack with a wood-screw. It might bementioned here that it is often necessary to drill a hole with a smallhand drill before driving the screw in, to prevent splitting the wood. 

After the base piece is fastened to the stack, the base in turn is heldto the deck of the boat by two small screws driven up from beneath. Theguy-wires can then be fastened on. The guy-wires should be made of veryfine wire, since heavy wire would be entirely out of proportion. Thewire can be fastened on the stack by drilling a tiny hole through thestack. A knot is then tied in one end of the wire, and the opposite endthreaded through the hole. Small screw-eyes driven into the base pieceare used to anchor the guy-wires. 

Ventilators are a very important part of the boat. The model-builderwill encounter considerable trouble if he attempts to make hiscowl-ventilator from metal, unless he is very experienced in drawingcopper out by hand. The writer has found a method of producingcowl-ventilators by the use of clay pipes. Clay pipes can be purchasedfor a few cents each, and when cut down as shown in Fig. 96 they formvery suitable ventilators. The pipe can be cut as shown by the use of afile. The ventilator is held to the deck of the boat by being forcedinto a hole in the deck that is just a trifle under size. Of course, theforcing will have to be done carefully to prevent the stem fromcracking. The inside of the ventilator should always be painted red, andthe outside should be the same color as the boat. Ventilators made inthis way absolutely defy detection and do much toward bettering thegeneral appearance of the craft upon which they are used. 

[Illustration: FIG. 98]

[Illustration: FIG. 96]

A simple searchlight, easily made by the model boat builder, is shownin Fig. 97. This is an electric light, and the batteries used to propelthe boat can be used for the light. First a small circular piece of woodis cut out, as shown at _A_, Fig. 97. The center of this is drilled outto accommodate a small flashlight bulb. A tiny brass screw is thendriven into the piece of wood, so that it will come in contact with thecenter of the base of the flashlight bulb. This little screw forms oneof the electrical contacts, and one of the wires from the battery isattached to it. 

A little strip of brass is then cut as shown in _B_, Fig. 97, andprovided with three holes, one hole at each end and one in the middle. The brass is bent into a semicircular shape, so that it will be just alittle larger in diameter than the outside of the wooden piece in whichthe flashlight bulb is mounted. This little piece is then fastened to awooden post with a small brass pin, as shown in Fig. 97. Two more pinsare used to hold the wooden piece to the searchlight proper. One ofthese pins is driven through the wooden piece until it comes in contactwith the base of the flashlight bulb. This forms the other electricalconnection, and the second feed wire from the battery can be attached tothe little brass piece that holds the searchlight. Both the feed wiresfrom the battery can come up through a hole in the deck close to thewooden post upon which the searchlight is mounted. 

Bollards are very easily made. Reference to Fig. 98 will make thisclear. First a little strip of brass is cut, and this is drilled asshown with two holes, one at each end and two smaller holes in thecenter. Two little circular pieces of wood are then cut, with a holethrough the center. A brass screw passes through these and into the deckof the boat. The brass screw should not be driven in too far, since thebollards should be free to revolve. It is also possible to use brasstubing instead of wood if the proper size is in the model-builder'sshop. 

[Illustration: A POWERFUL GASOLENE BLOW-TORCH

For a metre racing boat. Such a torch will deliver a steady, hot flamefor fifteen minutes]

A word will be said here about finishing the deck of a model boat. It isa very tedious job to cut separate planks to form the deck. In fact, this job is quite beyond the ability, to say nothing of the patience, ofthe average young model-builder. A very simple method of producingimitation planking is shown in Fig. 99. A sharp knife and astraight-edge are the only tools for this work. The straight-edge ismerely used to guide the knife. The cuts should not be made too deep, and they should be made a uniform distance apart. When the deck isfinished in this manner and varnished over, a very pleasing effect isproduced. In fact, if the work is done carefully, the deck looks verymuch as if it were planked. 

[Illustration: JUST AFTER THE RACE

A line-up of the entries in one of the power boat races held at CentralPark, New York City. The author presented the cup to the owner of ElmaraIII, the winning boat, which attained a speed of nearly thirty miles anhour]

[Illustration: FIG. 99]

[Illustration: FIG. 100]

[Illustration: FIG. 104]

[Illustration: FIG. 101]

A small life-boat is shown in Fig. 100. This can easily be carved toshape from a small piece of soft white pine. The center is gouged out, and tiny little seats made of thin strips of wood are glued in place. Two small screw-eyes are placed in the boat, for fastening it to thedavits. The davits are shown in Fig. 101, at _A_ and _B_. They are madeby bending a piece of small brass rod, as shown. One end of the rod ishammered flat, and a hole is made in it with a very small drill. Holesa little under size are drilled in the deck, and the davits are forcedinto these. The method of suspending the life-boat from the davits isshown at _B_, Fig. 101. The little blocks of wood are glued on to athread to represent pulleys, and they are, of course, only imitation ordummy pulleys. 

[Illustration: FIG. 102]

The method of producing port-holes is shown in Fig. 102. A hole is firstbored through the wood with a bit of the proper size. The size of theport-holes depends entirely upon the size of the boat. A piece of brasstubing is then cut off with a hacksaw to form a brass bushing. Theoutside diameter of this tubing should be the same as the size of thebit used. For instance, if a 1/2-inch bit is used, brass tubing 1/2 inchin diameter should be purchased. Such tubing can be obtained from anyhardware store. Celluloid, such as that used for windows in automobilecurtains, is glued to the inside of the port-holes. This makes asplendid substitute for glass. It can be obtained at garages andautomobile supply stores for a few cents a square foot. The model boatbuilder can also use either mica or glass for this purpose, althoughthick glass looks somewhat out of place. 

A binnacle is shown in Fig. 103. This is made from a solid piece of woodcut with a semi-spherical top. The steering-wheel is made of a wheelfrom an old alarm clock. The teeth of the wheel should be filed off. Tiny pieces of wire are then soldered in place on the wheel, as shown. Apin driven through the center of the steering-wheel is used to fasten itto the binnacle. The binnacle itself can be held to the deck either byglue or by a small screw. 

[Illustration: FIG. 103]

A torpedo-tube for use on model destroyers and battleships is shown inFig. 104. First two disks of wood are cut. Then a circular piece iscut, as shown. Two brass nails are then driven through this piece intoone of the disks. An upholstering tack is driven into the end of thecircular piece, as pictured. The method of attaching the torpedo-tube tothe deck is clearly illustrated in Fig. 104 and no further directionsneed be given. If the model-builder has a small piece of brass tube onhand suitable for use in this case, it will make a much better appearingtube than the piece of wood illustrated. 

A wireless antenna is shown at Fig. 105. This is a fitting that will domuch toward improving the appearance of any craft. Very fine copper wireis used for the aërial. The little spreaders are cut to shape from wood, and a tiny hole is punched through them through which the wire isplaced. Black beads slipped on the wire serve very well as insulators. The lead-in wire which drops to the wireless cabin is attached to theaërial by winding it around each one of the aërial waves. The aërialshould be suspended between the masts of the vessel. A few words shouldbe said about masts in general. If there is one way in which amodel-builder can destroy the appearance of a model boat, it is by usingbadly proportioned masts. The average boy seems inclined to use a mastof too great a diameter, which makes it out of proportion with the restof the boat. It is better to have a mast too small rather than toolarge. 

The method of producing railing is shown in Fig. 106. The same smallbrass rod that was used for the davits can be used for the railstanchions. One end of the stanchions is hammered flat and drilled out. The stanchions are fastened to the deck by first drilling small holesand forcing them into it. Thread or very fine wire is used for therailing. Fine wire is preferred owing to the fact that it will not breakso easily under strain. 

[Illustration: FIG. 105]

[Illustration: FIG. 106]

[Illustration: FIG. 108]

[Illustration: FIG. 107]

[Illustration: FIG. 109]

[Illustration: FIG. 110]

Fig. 107 shows a good method of producing stairs. It must be rememberedthat stairs are often used in model-boat construction. First a strip oftin is bent as shown. Then two more strips, which act as side pieces, are cut. One of these strips is soldered to each side of the stairs. Then six stanchions, which can be made from heavy copper wire, aresoldered to the side pieces, as shown. The railing can be made fromcopper wire or black thread. 

Fig. 108 shows a small skylight placed on the deck. This is easily madefrom cigar-box-wood glued together. The holes in the top pieces for thewindows are cut with a very sharp knife. It will be necessary to use alittle patience in this, to prevent the piece from splitting and toprevent cracks. A piece of celluloid is glued underneath the top piecesbefore they are finally glued in place. 

A small quick-firing deck-gun is shown in Fig. 109. This is a verysimple fitting and can be made with very little difficulty. The base ofthe gun is formed by cutting a thread-spool in half. A piece of smallbrass tubing is used to form the barrel. A little piece of sheet tin islooped over the back of the gun to represent the breech. A tiny piece ofwire is held to the side of the breech with a drop of solder, torepresent a handle. The shield of the gun is cut from a piece of tin, as shown. A hole is made in the bottom of this, so that the nail thatpasses through the barrel of the gun will also pass through this holeand into the spool. The center of the spool should be plugged to holdthe nail. After the gun is painted gray or black it will appear verybusinesslike, considering the small amount of labor spent in producingit. 

Anchors are more or less difficult to make (Fig. 110), and unless thebuilder is endowed with a great amount of patience he will not be ableto file them out of solid metal. A dummy anchor can be easily cut out ofwood, however, and when painted black it will answer instead of a metalone. The anchor shown at _A_ is a very simple type made out of a solidpiece of wood. The one at _B_, however, is made out of two pieces ofwood fastened together with a pin, as shown. The bottom piece of theanchor shown at _B_ should be rather thick to get the proper effect, andthe two points should be tapered nicely. The center of the bottom pieceshould be hollowed out to accommodate the vertical piece. 

A common hatch is shown at Fig. 111. This can be made in the form of anopen box from cigar-box wood, and glued to the deck. It is not necessaryto cut a hole in the deck for this purpose. 

[Illustration: FIG. 115]

[Illustration: FIG. 116]

[Illustration: FIG. 111]

[Illustration: FIG. 113]

A cargo-hoist for use on model freight-boats is shown in Fig. 112. Thisis a very simple piece of work and will need little description. Severalstay-wires should be fastened to the main-mast and held to the deck withsmall screw-eyes. The boom should be made a trifle smaller in diameterthan the mast. The pulleys are dummy, like those on the life-boat. Alittle hook bent to shape from copper wire is placed on the end of thethread, as shown. 

[Illustration: FIG. 112]

[Illustration: FIG. 114]

Fig. 113 shows a method of making a whistle and an engine exhaust. Theengine exhaust is made of a piece of wood, and the furled top isproduced by an eyelet such as those used in shoes. The engine exhaust isalways placed immediately back of the last smokestack. The whistle is asimple device made almost entirely of wood. The whistle-cord is ofthread attached to the small piece of wire, as shown. 

Fig. 114 shows the method of making spray-cloths for the top of thepilot-house. Small brass brads are driven into the top of thepilot-house, and white adhesive tape is placed on the brads, aspictured. Advantage can be taken of the adhesive substance on the tapewhich holds it in place on the brads. 

A rudder is shown in Fig. 115. The rudder-post should be a piece ofbrass rod so thick that it can be split with a hacksaw. The sheet brassthat forms the rudder proper is placed in this split and soldered. Inthe case of an ornamental boat the rudder can be fixed as shown in Fig. 115. It will be seen that it is quite impossible to keep the rudder inadjustment in this way. 

If the rudder is to be kept in a certain adjustment a quadrant isnecessary. This is made by using a semicircular piece of heavy sheetbrass and filing little notches in it. The lever of the rudder rests inthese notches, and by this means the rudder can be held in any oneposition, so that the boat will either turn in a circle or go straight. Fig. 116 illustrates such an arrangement. 

CHAPTER X

THE DESIGN OF MODEL STEAM-ENGINES

INSTEAD of describing the construction of several model engines ofdifferent design, the author thinks it advisable to put the reader inpossession of the fundamentals of model steam-engine design andconstruction. In this way the model engineer will be able to design andconstruct model steam-engines according to his own ideas and inaccordance with the raw materials and miscellaneous parts he may find inhis workshop. Unless the young mechanic is in possession of a very wellequipped workshop, it is quite impossible to construct a steam-engineaccording to certain specifications. However, if he has in mind thefundamental principles of steam-engine design, he can go ahead anddesign his engine, for which he will have no trouble in machining orproducing the parts that enter into its construction. By this theauthor means that the workman can design his engine to meet thematerials he has on hand. 

Notice Fig. 117. This is a cylinder into which is fitted a piston. Ifsteam is forced into the cylinder the piston will be forced to theopposite end of the cylinder. If some means is then provided so that thesteam can escape and the piston come back, another impulse can be givenit by admitting more steam, and thus a continuous motion may beproduced. This is how the steam-engine works. 

[Illustration: FIG. 117]

Having learned how motion is imparted to the piston by the expansion ofsteam under pressure, attention is directed to what is known as the "D"slide-valve. This slide-valve permits steam to enter the cylinder and toexhaust at proper intervals. See Fig. 118. Steam enters the steam-chestthrough the pipe _A_. The slide-valve is shown at _D_. When theslide-valve is in the position shown, steam enters the cylinder, and bythe time the cylinder has arrived in the position shown by the dottedline _C_, the slide-valve moves over, closing the passage _B_. The steamunder pressure forces the piston to the opposite end of the cylinder. When the piston reaches the opposite end of the cylinder, steam that hasentered through the passage _F_ again forces the piston back to itsoriginal position. This is caused by the slide-valve shifting itsposition, because of the impulse it received at the opposite end of thecylinder. Thus it will be seen that when the piston is at one end of thecylinder the opposite end is exhausting. By carefully studying Fig. 118the action of the _D_ valve will be understood. The connecting-rod _E_is connected to the crankshaft and in this way the engine is caused torevolve. 

[Illustration: FIG. 118]

A cylinder similar to that shown in Fig. 118 is called a double-actingcylinder. This is because the steam acts on both sides of the piston. Single-acting cylinders are cylinders in which the steam expands on onlyone side of the piston. In the single-acting engines the _D_ valve ismodified. 

The "stroke" of a steam-engine depends upon the length of the cylinder;really, the stroke is the distance travelled by the piston. In modelengines it ranges from 3/8 of an inch to 1-1/2 inches. The bore of acylinder is its internal diameter. The bore is usually a trifle smallerthan the stroke. Thus it is common to have a stroke of 7/8 inch and acylinder-bore of 3/4 inch. 

At this juncture the author would caution the more inexperienced youngmechanics not to build double-acting engines. The valve mechanism issomewhat intricate and very difficult to regulate. The construction isalso much more complicated, and this also holds true of the designing. On the other hand, single-acting engines, while not so powerful for agiven size, will do very nicely in driving model boats, and will deliversufficient power for all ordinary purposes. 

[Illustration: FIG. 119]

Your attention is directed to Fig. 119. This shows a design for a modelsingle-cylinder, single-acting steam-engine. The reader should carefullystudy each drawing before continuing to digest the following matter. Thecylinder _L_ can be made from a piece of tubing. This can be eitherbrass or copper. Aluminum should not be used, owing to the fact that itis difficult to solder and difficult to work with. The piston is made sothat it will fit nicely into the cylinder and move up and down withoutbinding. It will be seen that a groove, _M_, is cut around the pistonnear the top. String soaked in oil is placed in this groove. This iscalled packing, and the presence of this packing prevents steam leakagebetween the piston and the cylinder walls and thereby materiallyincreases the efficiency of the engine. 

In this case the connecting-rod _R_ is made in a circular piece. It isattached to the piston by a pin, _F_. The connecting-rod must be free torevolve upon this pin. The engine shown has a stroke of 7/8 inch. Therefore, the crank-pin _K_ on the crank-disk _N_ must be placed 1/2 of7/8 or 7/16 inch from the center of the disk _N_, so that when this diskmakes one revolution, the piston will move 7/8 inch in the cycle. Thusit will be seen that the distance of the crank-pin _K_ from the centerof the crank disk _N_ will depend entirely upon the stroke of theengine. It may be well to mention here that the worker should alwaysstart designing his engine by first determining the bore and stroke. Everything depends upon these two factors. It is also well to mentionhere that the piston should never travel completely to the top of thecylinder--a small space must always be left for the steam to expand. One eighth of an inch is plenty of space to leave. 

It will be noticed that the valve mechanisms on the particular engineshown bear no resemblance to the _D_ valve previously described. Theholes _G_ which are bored around the cylinder are the exhaust ports. Itwill be seen that when the piston is at the end of its downward strokeit uncovers these exhaust ports and permits the steam to escape. Themomentum of the flywheel _A_ pushes the piston upward, closing theseholes. As these holes are closed the valve _H_ uncovers the entrance _I_and permits steam to enter from the boiler through _J_. By the time thepiston has reached the upward limit of its stroke a considerable steampressure has developed on top of the cylinder, and this again forces thepiston downward. Thus the same cycle of movement is gone throughrepeatedly. 

The valve on this little engine is extremely simple. It consists of acircular piece of brass drilled out, as shown. A hole (_I_ and _J_) isdrilled transversely through this. The little cylinder shown in theinsert at _O_ slides in the larger hole, and when it is at its upperlimit it cuts off the steam. At the proper intervals the valve is pulleddown by the eccentric _C_. It will be seen that the moving parts, i. E. , the valve and the piston, must be properly timed. That is, the eccentric_C_ must be mounted on the crank-shaft _B_ so that the valve will closeand open at proper intervals. When the engine is made, the eccentric canbe shifted about by means of a set-screw, _Q_, until the engine operatessatisfactorily. This set-screw is used to hold the eccentric to thecrank-shaft. The word eccentric merely means "off center. " Thus theeccentric in this case is formed by a little disk of brass with the holedrilled off center. The distances these holes are placed off center willdepend entirely upon the motion of the valve. It will be seen that thevalve is connected to the eccentric by means of the valve-rod _E_. Thevalve-rod, in turn, is held to a circular strap which is placed aroundthe eccentric. A groove should be cut in the surface of the eccentric, so that this strap will not slip off. If the strap is not put on tootightly and the eccentric is free to revolve within it, the valve willbe forced up and down as the eccentric revolves. 

The crank-shaft _B_ revolves in two bearings, _D D_. The flywheel isheld to the crank-shaft by means of a set-screw _S_. 

Most small engines with a bore under one inch will operate nicely onfrom 20 to 30 pounds of steam, and this pressure can easily be generatedin the boiler that was described in the chapter on model-boat powerplants. 

CHAPTER XI

A MODEL FLOATING DRY-DOCK

AS many of the readers probably know, a dry-dock is used in assistingdisabled vessels. Some dry-docks are permanent, while others are builtso that they can be floated or towed to a disabled vessel that is notable to get to a land dry-dock. The land dry-dock operates as follows. It is first filled with water, and the disabled boat is towed in bytugs. After the tugs leave, the gates are closed, and the water in thedry-dock is pumped out, leaving the boat high and dry. Large props areput in place to prevent the boat from tipping. 

The dry-dock here described is a model that is towed to a disabledvessel. It is then sunk until it passes under the boat. The sinking isbrought about by filling the dry-dock with water. After it has sunk tothe proper depth it is passed under the boat to be repaired, the wateris pumped out, and the dry-dock rises, lifting the disabled boat withit. Repairs can then be made very easily. 

The model here described does not possess all the fittings and additionsof the original. However, it is able to rise or sink as required, carrying the machinery necessary to bring about these functions. 

[Illustration: FIG. 120]

[Illustration: FIG. 121]

A general view of the completed model is shown in Fig. 120. The firstpart to construct is the framework for the hull. Four pieces of woodwill be required for this, and they should be cut to the shape and sizeshown in Fig. 121. To make this it is best to cut the two side partsfirst, as indicated by the dotted lines. This done, the bottom piece canbe clamped on from behind by means of pieces of lath. These are for thetwo end pieces. The other two pieces are made in the same way, exceptthat they contain holes for the water to pass through, as shown at _B_. The wood for these frames, or ribs, should be not less than 1/4 inchthick in order to accommodate the pieces used in the construction of theremainder of the hull. 

When the builder has made the four ribs, he should proceed to constructthe lower deck, which consists of a single piece of wood nicely planedand finished, measuring 14-1/2 inches long by 8 inches wide and 1/8 inchthick. This piece must be nailed to the bottom of each of the ribs, oneat each end, and the other two containing the holes at equal distancesapart. Tiny nails, similar to those used on cigar-boxes, will be foundvery suitable for this work. Some old cigar-boxes may be broken apart toobtain the nails for this purpose. Before nailing on the board it shouldbe marked out to present ordinary deck-boards. The reader is referredback to Chapter 9 which describes this process, using a straight-edgeand knife. 

When this board is nailed in place, the next requirement will be twopieces for the sides the bottom edges, of which must rest on the top ofthe deck-board. These boards are the same length as the deck. Theyshould reach to the top of the ribs, and be fastened in the same way asthe bottom deck. It is good practice, when doing this, to place a littlewhite lead on the bottom edge before finally driving the nails in place. This will tend to produce a water-tight joint. This done, three piecesof wood 5/8 inch square must be screwed in place, flush with the bottomends of the ribs, to form a flat keel. They should be firmly fixed sincea lead keel is afterward screwed on the bottom of the boat. Attentionshould now be directed to fitting the two middle decks. These are placed4 inches from the top and are 4 inches wide. In this space the engineand pumps are placed. Therefore, the top deck is made in the form of alid, and the outside plate made to draw out. In this way the mechanismbelow the deck can be made very accessible. 

The framework of the dry-dock is now completed, and the builder canproceed to fix on the side plates. These are made from sheet tin with awidth of 14-1/2 inches. The length must be sufficient to reach from thetop of one side, around the bottom of the hull, to the top of the otherside. Having cut the tin to the required size, one side is put in placewith small nails, spacing them an equal distance apart. 

Before securing the opposite side, the builder must first arrange theinlet-valve. This particular member is constructed as follows. First, obtain an old gas-pipe union which measures about 5/8 inch in diameterand 3/4 inch long. With a hacksaw this is cut off in a sloping directionwith an angle to correspond with the slope in the bottom of thedry-dock. When this is done, a lid must be fitted to the top by means ofa long rod, as clearly shown in Fig. 122. On the under side of this lida small piece of sheet rubber should be glued, so that when the lid isscrewed down the valve will be made water-tight. The valve must now besoldered to the inside of the hull. It is placed in such a position thatit will rest just under the center of one of the upper decks when thecontrolling rod is upright. 

[Illustration: FIG. 122]

The top end of the rod must contain a thread for about 1 inch, and around plate made to screw on. This plate should be about 3/4 inch indiameter, and contain three small holes around the edge. These holes areused in fastening the plate to the deck. The top of the rod is fittedwith a small crank-handle, which is used in turning the rod in eitherdirection. In this way the valve can be either opened or closed. At thebottom of the rod a small swivel should be provided, as indicated inFig. 122. 

The plate or sheet of tin on this side of the hull can now bepermanently fixed in place. When this is done a light hammer should beused around the edges to turn the tin into the wood. 

With the plates secured in place, the builder must next fix a flat woodkeel along the bottom of the dry-dock. This should be screwed to theinside keel, screws passing through the tin plate. A lead keel is thenscrewed to the wooden keel, and when this is done the dry-dock can belaunched. If the foregoing instructions have been carried out carefullythe dry-dock should ride lightly on the water. 

As a trial the inlet-valve is now unscrewed and water is permitted toenter the hull. When the water rushes in, the hull will begin to sink. The water should be allowed to enter until the hull sinks to within aninch of the lower or inside deck. The valve should then be closed. Theexact position of the water should now be found, and a line drawn allaround the hull, which can afterward be painted in. 

The engine and boilers must now be constructed and placed on thedry-dock, so that the water that was permitted to enter may be pumpedout. As a temporary arrangement, a thin rubber tubing is insertedthrough a hole in the lower deck and allowed to hang outside thewater-level. The siphon can then be formed by simply drawing the waterup by suction with the lips. A continuous flow will result, emptying thehull within a short time. 

[Illustration: FIG. 123]

Attention is now directed to the construction of the boiler and pumps. The boiler, which is rectangular in shape, is made of thin sheet copper, and measures 4 inches long by 3 inches wide by 2 inches deep. A hole ismade in the top, and a brass or copper tube 6 inches long and about 3/4inch in diameter is soldered in position, as depicted in Fig. 123. Thistube acts as a chimney on the dry-dock, but it is really used forfilling the boiler, and the top is supplied with a tightly fittingcork. 

The ends of the boiler also act as supports, and they are made 4 incheslong. The bottom edge is turned up for about 1/4 inch to enable theboiler to be screwed firmly to the lower deck. The boiler occupies aposition at one end of the hull, and should fit easily in between decks. A small spirit-lamp is used to furnish heat, and no description need begiven of this particular part of the equipment. Before the boiler isfirmly fixed in place a small hole should be made near the top at oneend. The feed steam-pipe is inserted in this, and soldered in place. 

Two small oscillating cylinders, similar to those made for the engine onthe _Nancy Lee_ (Chapter 6), should be made. They should not be morethan 3/4 inch in length, with a 3/8-inch bore. If the builder has anyold model steam-engines in the shop, he may take the cylinders from theminstead of constructing new ones for the dry-dock. 

The engine is set up as shown in Fig. 124. The first job is to make theframe or standards, and this is in one piece. Two pieces of brass (_A_), measuring 5-1/2 inches long by 1/2 inch wide and 1/16 inch in thickness, are cut. Next the builder should mark off 1-1/2 inches from either end, and carefully bend at right angles, after which holes are drilled toaccommodate the crank-axle _B_. Two holes must also be made for screwsto enable the machine to be screwed to the deck. 

[Illustration: FIG. 124]

[Illustration: FIG. 125]

The flywheel should be 1-1/2 inches in diameter, while the bent crankhas a throw of 3/16 inch. The steam-cylinder is fixed on the outside ofone of the uprights, and the steam-pipe must, of course, be fitted fromthe inside. 

The pump-cylinder is composed of a small piece of brass tube 1 inch longand 3/8 inch in diameter. The plunger is 1/2 inch long, and the diameteris just sufficient to enable it to work freely up and down inside thebrass tube. One end is shaped as shown in Fig. 125. This contains a sawcut that enables the pump-rod to be placed between and connected with apin. The bottom end of the cylinder is now fitted with a brass disk inwhich a hole is made and a 3/32-inch tube soldered in place. The insidesurface of this piece of brass should be countersunk, and the piece isthen soldered into the end of the cylinder. Before the plunger isinserted a small lead shot is dropped in, which should be larger thanthe hole at the bottom of the cylinder, thereby covering it. A hole isdrilled in at the side of the cylinder, and a small bent pipe fixed init. At the top of this pipe a short piece of 3/8-inch brass tube isfixed in place, as indicated. This piece of tubing is closed at bothends. The bottom end is treated like that of the pump-barrel andsupplied with a large shot. An outlet-pipe is soldered into the side ofthe delivery-valve chamber and leads to the side of the hull. 

The pump _E_ is fixed at the bottom midway between the engine uprightsas indicated in Fig. 124. The suction-pipe passes through a hole anddown through the deck nearly to the bottom of the hull. After theengine and boiler are connected, a trial can be made. If the foregoinginstructions have been carried out, the engine will run at a good speedand a continuous flow of water will be pumped out of the hull. All partsof the engine and pump should be carefully oiled and water should bepoured into the pump in order to prime it before its start. 

It is understood that two complete boilers and pump units are made forthe model, and one is mounted on each side. If the builder desires toincrease the capacity of the pumps and install a more powerful boilerand engine, only one pump will be necessary. Otherwise the water willnot be pumped from the hull very rapidly. 

When the builder has finished the pump units, he should turn hisattention to the remainder of the fittings. Two small cranes are made, and one is placed at each side of the hull. They are made of tin. Thecab of each crane measures 2-1/2 inches high by 2 inches long by 1-3/4inches wide. A small roof is fitted on, and a piece of wood fitted tothe bottom to serve as a floor. The jib measures 6 inches long by 3/4inch at the base, and tapers to 1/2 inch. It has 1/4 inch turned down ateach side, thus adding considerable strength. The jib is fitted to thecab by means of a wire passed through the sides, and two guy-ropes arearranged as shown. A small piece is now cut out at the top, and a pulleywheel fixed in position by means of a pin passed through the sides. 

[Illustration: FIG. 126]

The winding-drum can be made of either tin or wood. The axle passesthrough both sides of the cab, the crank being attached to the outside. Fig. 126 shows the completed crane, which is held to the deck by meansof a small bolt and nut. A washer should be placed between the bottom ofthe crane and the deck, to allow the crane to turn freely with littlefriction. 

A hand-rail, made of fine brass wire, is placed around the deck. 

Dummy port-holes are fixed to the sides of the dry-dock for the purposeof lighting up the interior of the engine-room. These are furnished fromtop rings taken from gas-mantles. Anchor-chains are fixed at each end ofthe dry-dock. The whole dry-dock is painted with two coats of gray paintand the water-line painted in bright red. 

[Illustration: FIG. 127]

Fig. 127 shows the dry-dock with a model boat in position. 

CHAPTER XII

OPERATION OF FLASH STEAM POWER PLANTS FOR MODEL BOATS

THE flash steam method of propelling model power boats of the racingtype produces a far greater speed than would otherwise be possible. Flash steam plants are far more complicated than ordinarysteam-propelled power plants, and for this reason the author devotes achapter to their description. 

A considerable equipment of tools and not a little mechanical ingenuityare required to produce and assemble a workable flash steam plant. However, such plants have gained great popularity in the past few years, and all of the hydroplane racing craft are propelled with such outfits. These power plants are capable of delivering such a tremendous powerthat speeds as high as thirty-five miles an hour have been reached byboats measuring 40 inches long. 

The illustration, Fig. 128, shows a flash steam plant and its variousparts. Each part and its function will be described in this Chapter indetail. The gasolene tank _A_ is used to hold the fuel, which is fed tothe gasolene burner _C_. The gasolene burner operates on the principleof the ordinary gasolene torch. First the tank is filled aboutthree-quarters full with gasolene. An air-pressure is then produced inthe tank with a bicycle pump. The pipe leading from the gasolene-tank atthe top is coiled around the burner, and the free end of it is bent andprovided with a nipple, so that the gasolene vapor will be blown throughthe center of the helix of the coil formed by the pipe bent around theburner. This is quite clearly shown in the drawing. 

[Illustration: FIG. 128]

The cylinder is merely a piece of stovepipe iron bent to shape andprovided with several air-holes at the burner end. To start the burner, the vaporizing coils must first be heated in an auxiliary flame. Theflame of an ordinary blow-torch is suitable for this purpose. Afterthe coils have become sufficiently hot the valve at the top of thegasolene-tank is opened, and this causes a stream of gasolene vapor toissue at the nipple. This produces a hot flame at the center of thevaporizing coils, and in this way the coils are kept hot. The purpose ofheating these coils is further to vaporize the gasolene as it passesthrough them on the way to the burner. Once started, the action of theburner is entirely automatic. The vaporizing coils are made of Shelbysteel tubing with an internal diameter of 1/8 inch. 

It will be seen that the flame from the gasolene-torch is blown throughthe center of the boiler coils _B_. Thus, any water passing throughthese boiler coils is instantly converted into steam. In other words, the water "flashes" into steam. The heat of the blow-torch is so greatthat most of the boiler coils are maintained at red heat even while thewater is passing through them. 

Notice the water-tank _G_. A little scoop, formed by a pipe of smalldiameter, protrudes through the bottom of the boat, so that the forwardmotion of the boat will cause water to rise in the tank _G_. Anoverflow is also provided, so that, should the water not be sucked outof the tank quickly enough, it will not flood the boat. The overflowpipe hangs off the side of the boat. 

The water pump _E_ sucks water from the tank, and pumps it through thecheck-valve _K_ (this valve permits water to pass in one direction only)into the boiler coils. The boiler coils, being red-hot, cause the waterto flash into steam the instant it reaches them. By the time the steamhas reached the opposite end of the boiler coils, it is no longer steam, but a hot, dry gas at a terrific pressure. From the boiler coils thesteam passes into the steam-chest of the engine, and thence into thecylinder, where it expands, delivering its energy to the piston. 

It will be seen that the water-pump _E_ is geared to the engine. Owingto this, it is necessary to start the water circulating through theboiler coils by the hand pump _F_. This hand pump forces water throughthe boiler coils just as the power pump does. After the hand pump isstarted the engine is turned over a few times until it starts. Thevalve _H_ is then closed, which cuts the starting pump _F_ entirely outof the system, because when the engine starts it also drives the waterpump _E_, and therefore the action becomes entirely automatic. 

The relief-cock _L_ is placed in the system to be used if the enginestalls. By opening the relief-cock the pressure in the complete systemis immediately relieved. At all other times the relief-cock is closed. 

A second pump, _I_, is also included in the system. This, like thewater-pump, is geared to the engine and driven by it. It is the duty ofthis pump to convey oil from the lubricating tank _M_ into the steamfeed-pipe just before it enters the steam-chest. In this way the livesuperheated steam carries a certain amount of lubricating oil with it inthe cylinder. 

Owing to the high temperature of the superheated steam, it is impossibleto use brass cylinders on the steam-engines employed with flash steamsystems. Steel seems to be the only cheap metal that is capable ofwithstanding the attack of flash steam. Brass is out of the question, since its surface will pit badly after it is in use a short time. 

The boiler of a flash steam plant is covered with sheet iron so as toprevent drafts of air from deflecting the flame from the center of theboiler coils. The cover is provided with ventilators, so that the burnerwill not be smothered. If enough oxygen does not enter the interior ofthe boiler coils, poor combustion will result, and the gasolene flamewill not develop its maximum heat. Upon referring again to the diagram, it will be seen that the exhaust steam pipe from the engine dischargesinto the stack of the boiler covering. This discharge greatlyfacilitates the circulation of air through the boiler coils. 

After a flash steam plant has been started it will work automatically, providing all the parts are in good running order. Flash steam plants, however, are difficult to get in the proper adjustment, and onceadjusted they are easily disturbed by minor causes. Owing to the factthat every square inch of surface in the flash coils is heating surface, the amount of water supplied to the boiler must be exactly what isneeded. The heat must also be regulated so that the temperature of thesteam will just meet the engine's needs. Many times an increase in heatcauses the steam to reach such a temperature that it will burn up thelubricating oil before it reaches the cylinder of the engine. This isliable to cause trouble, because sticking is apt to occur. 

Model power boats with speeds as high as thirty-five miles an hour havebeen made in America. Such high-speed boats must be assembled withinfinite care, owing to the fact that the mechanism they carry is moreor less erratic in its action, and unless it is well made results cannotbe expected. 

[Illustration: FIG. 129]

There are probably few sports more interesting than that of modelpower-boat racing. The Central Park Model Yacht Club of New York city isone of the most progressive clubs in America, and its members not onlyhave a sail-boat division, but they also have a power-boat division. Themembers of the power-boat section have races regularly once a week, andthe most lively competition is shown. It is indeed amusing to watchthese little high-speed boats dash across the pond, their bows high inthe air and their little engines snorting frantically. Owing to thedifficulty of keeping these small racing boats in a straight line, theyare tied to a wire or heavy cord and allowed to race around a poleanchored in the center of the pond, as illustrated in Fig. 129. The topof the pole should be provided with a ball-bearing arranged so that thecord to which the boat is fastened will not wind around the post. Inthis way the boats are caused to travel in a circle, and as the cord towhich they are fastened represents the radius of the circle, thecircumference can readily be found by multiplying the radius by 2, which will give the diameter. The diameter is then multiplied by 3. 1416to obtain the circumference. If the boats were permitted to travel wildthey would run into the bank, a fatal procedure when they are running athigh speed. 

Speed boat hulls are usually of the hydroplane or sea-sled type. Thistype of hull is extremely easy to make. Such a hull is shown in Fig. 130. It will be seen that it has an aluminum bottom. The propeller andpropeller strut will be noticed in this illustration. 

[Illustration: FIG. 130]

[Illustration: FIG. 131]

[Illustration: FIG. 132]

The drawing for the particular hull shown in Fig. 130 is given in Fig. 131. First the two side pieces are cut out to the shape shown. In thisparticular instance the over-all length of the sides is 39-1/3 inches. This is called a meter boat, and is built with this length to conformwith the English racing rules. Next a bow piece is cut out, and this isproduced from solid wood. Only two materials are used in theconstruction of this hull, aluminum and mahogany. Square mahogany stripsare cut out and fastened inside of the side pieces by means of shellacand 3/8-inch brass brads. The bottom of the hull is made of 22-gagesheet aluminum. This is fastened to the square mahogany strips, sincethe sides of the boat are entirely too thin for this purpose. The methodof fastening the strips of aluminum will be made evident by referring toFig. 132. The aluminum bottom does not run completely over the bowpiece, but merely overlaps it sufficiently to be fastened by brassbrads, as illustrated in Fig. 135. The single step in the bottom of theboat is fastened by a mahogany strip, through which the stern-tube runsand the water-scoop. The back of the boat is made up of mahogany. Asmall aluminum hood is bent to shape, and this is fastened to the bow ofthe boat and prevents the boat from shipping water. 

In building a hull of this nature the mechanic should exercise care tosee that it is in perfect balance, and that the sides are finished andvarnished as smoothly as possible. This will cut down both air and waterresistance. The position of the propeller strut and stern-tube will beseen by referring to the drawing of the hull in Fig. 131. 

The propeller of a high-speed boat is of a high pitch and generally ofthe two-blade type. It should be at least 3 inches in diameter and witha pitch of about 10 inches. By this it is meant that the propellertheoretically should advance 10 inches through the water for onerevolution. The rudder is generally fastened in one position, in casethe boat is not used on a string and pole. It will be found advisable, however, always to run the boat in this way, and in such cases therudder can be entirely dispensed with. 

[Illustration: FIG. 133]

The boiler of a flash steam plant is extremely simple. Such a boiler isshown in Fig. 133. It consists merely of a coil of copper or Shelbysteel tubing with an internal diameter of 1/4 inch. The boiler coilsshould be wound around a circular form of wood about 2-3/4 inches indiameter. In the case of copper it will not be found very difficult todo this, providing the copper is heated before being wound on the woodenform. If the copper is heated it is advisable to wind the wood with alayer of sheet asbestos before the copper tube is wound on. It is almostnecessary to do this winding with a lathe, but if the mechanic does nothave access to such a tool he may have to find other means of doing it, or possibly he can take it to a local machine shop and have the workdone for a few cents. The boiler coil should be wound about 9 incheslong. 

A casing of Russian sheet iron is made to slip over the boiler, leavingsufficient space between. Ventilating holes or slots are cut in thecover to permit of a free circulation of air. The boiler covering isalso provided with a funnel through which the exhaust gases from theblow-lamp pass. 

[Illustration: FIG. 134]

[Illustration: FIG. 135]

The blow-lamp used operates on the same principle as the ordinaryblow-torch. The details of such a lamp are given in Fig. 134, and afinished torch is shown in Fig. 135. Instead of making the valvesnecessary for the blow-torch, it is advisable to purchase them, for theyare very difficult to make accurately. The valve at the back of thetorch regulates the gasolene supply that passes through the nipple. Thehole in the nipple should be about twenty thousandths of an inch. Owingto the fact that the copper coil wound about the burner is short, thetube can be filled with molten resin before it is bent. In this way thetube will not kink or lose its shape while being wound. After it iswound it is placed in the fire and the molten resin forced out with abicycle-pump. Such a blow-torch produces a tremendous heat and throws ahot flame far up into the boiler coils. 

CHAPTER XIII

SAILING YACHTS

BEFORE attempting to construct model sailing yachts the young workershould become thoroughly conversant with the different types of yachtsand their fittings. In the following pages the author briefly outlinesthe general science of yacht-making and sailing. 

Sailing yachts are made in four principal types. There is the cutterrig, yawl rig, sloop rig, and the ketch rig. The cutter rig is shown inFig. 136. It consists of four sails so arranged that the top-sail may beeither removed altogether or replaced by sails of smaller area. In allyachts it is necessary to haul the sails up into position by ropes knownas halyards. The halyards must be led down to the deck. Themodel-builder, however, can dispense with much of the gear used onlarger boats. 

A sloop rig is illustrated in Fig. 137. By studying the drawing theworker will see that the sloop rig differs from the cutter rig only inthat she carries a single sail forward of her mast. 

[Illustration: FIG. 137]

[Illustration: FIG. 136]

The yawl rig (See Fig. 138) is similar to a cutter rig, but has a smallsail set up on another mast abaft the mainsail. The sheet is led aft toa spar that projects beyond the counter. The mast upon which the smallersail is set is known as the mizzenmast. In this rig it will be seen thatthe main boom must be made considerably shorter than was the case inthe cutter rig. This is done so that it will not follow the mizzenmastwhen it swings from one position to another. 

[Illustration: FIG. 138]

[Illustration: FIG. 139]

The ketch rig differs greatly from the yawl rig. The mizzenmast alwaysoccupies a position forward of the rudder-post. In the yawl themizzenmast is always stepped aft of the rudder-post. This will be seenby referring to the drawings of the two boats. The ketch rig isillustrated in Fig. 139. 

The prettiest rig of all is the schooner; but, owing to the fact that itis difficult to get them to go well to windward unless the hull isperfectly rigged, the author has decided not to deal with this type ofboat. When the reader becomes proficient in building and sailing thesimpler types described in this book, he may turn his attention to theconstruction and sailing of more complicated types. 

_Model Yacht Parts_

The submerged portion of a yacht is, as in all other boats, termed thehull. The backbone of the hull is called the keelson. Attached to thekeelson is a piece of lead, which is put in place to give the boatstability and power to resist the heeling movement created by thewind-pressure upon the sails. This is known as the keel. 

Yachts always have an opening in the deck giving access to the interiorof the hull. These openings are known as hatchways. When sailing inrough weather the hatchway is closed by a hatch to prevent the yachtfrom shipping water. 

The extreme forward end of a yacht hull is called the stern, while theportions forward and aft of the midships section are known as the foreand after-body respectively. 

[Illustration: A TWIN CYLINDER STEAM ENGINE FOR MODEL MARINE USE

This engine will drive a boat several feet long]

In all yachts a portion of the hull extends out over the water. Theseportions are known as overhangs. The overhang aft is sometimes calledthe counter-stern. The sides of the hull that rise above the deck arecalled bulwarks, and the part of the bulwarks that cross the stern iscalled the taffrail. The taffrail is always pierced with holes to allowwater to run off the deck quickly, so that the additional weight willnot in any way affect the course of the boat. It is understood thatyachts raise great quantities of water upon their decks when travelingin rough sea. 

The bowsprit is passed through a ring at the top of the stern, and thisring is termed the gammon iron. Its end is secured in a socket orbetween a pair of uprights called the bowsprit bits. These are fixed tothe deck. Metal bars are fixed a short distance above the deck to takerings attached to the sheets. This is done so that the sails may swingfreely from one side of the boat to the other. Metal eyes are screwedinto the sides to take the shrouds, and are called chain-plates. The eyein the stern is called the bobstay plate. In the stern-post are two eyescalled gudgeons. The rudder is hooked to this by means of two hookscalled pintles. The bar or lever that is fixed to the top of therudder-post is called a tiller. 

[Illustration: A CUP-WINNING MODEL SAIL BOAT

Designed and constructed by the commodore of the Central Park ModelYacht Club, New York, N. Y. ]

The parts and fittings of a mast follow: the step, the head, the caps, crosstrees, truck, topmast, boom, and gaff. The part of the gaff thatrests on the mast is called the throat; the end of the gaff is calledthe peak. The jib-boom is a term used only in connection with modelyachts. In larger boats the jib-boom is an extension of the bowsprit. The small boom that projects over the stern of a yawl is called thebumpkin. The spar is rather a general term applied to practically allwooden supports of sails. The spar of a lug-sail is called the yard. Itis different from a boom or gaff, by reason of its lying against themast instead of having one end butting on the mast. Anything belongingto the mainmast should be distinguished by the prefix main. Thus, thereare the mainsail, the mainboom, main-topsail, etc. 

[Illustration: FIG. 140]

A sail for a model cutter-rigged yacht is shown in Fig. 140. Thebowsprit and masts are, when necessary, given support by ropes that arestretched tightly to some point where they can be conveniently anchoredto the hull. The following are those largely used on model yachts:topmast stay, bobstay, topmast shrouds, and forestay. 

The sails are pulled up and fastened by ropes termed halyards. Thehalyards are fastened to the upper portions of the sail, and they arenamed according to the sail to which they are attached. For instance, there is the jib halyard and the foresail halyard. A mainsail carried bya gaff has two halyards, the throat and peak. The movement of the sailsis controlled by ropes, called sheets, which take their names from thesails they control. There is a mainsheet, a jibsheet, and a foresheet. The reader should take note of this term and refrain from confusing itwith the sails. 

_Sailing Model Yachts_

The sailing of model yachts is a real art, and the author warns thereader that he cannot hope to become a proficient yachtsman by merelydigesting the information given in this book. His real knowledge must beearned by experience in handling a model yacht on the water. However, there are few sports that will afford more pleasure than that of sailingmodel yachts. Being an outdoor sport it is very healthful. 

In sailing a model yacht the sails are set, or "trimmed, " so that shewill continue to sail along the course previously decided upon by theyachtsman. She must do this in as speedy a manner as possible and withas little deviation from her original course as possible. The trim ofthe sails will depend upon the wind. If the boat is to sail against thewind, that is termed "beating to windward"; with the wind is called"scudding. " With the wind sideways it is called "reaching. " If the boatis sailed with the wind blowing midway between one of the sides and thestern in such a way that it sweeps from one side of the stern across thedeck, this is called "three-quarter sailing" in a "quartering" wind. Amodel yacht will continue for a great distance on a reach or whilescudding; but, on the other hand, it will not be possible for her tosail directly against the wind. If a yachtsman is to make headwayagainst the wind, he must sail his boat as near dead against the wind asit will go. 

The cutter type of yacht will move against a wind that is blowing at avery small angle on her bowsprit. As soon as she reaches the limit ofher course, the yachtsman turns her bow at a small angle so as to bringthe wind on the opposite side of the vessel, and in this way a secondcourse is started. These courses are repeated in a zigzag fashion untilthe yacht arrives at her destination. This zigzagging, or "tacking, " asit is called, is illustrated in Fig. 141. It will be seen that the yachtstarts at _B_, and makes 3 tacks before she arrives at her destination, _A_. Each time she touches the shore she is "put about" and set upon anew course, or "tack. "

[Illustration: FIG. 141]

It will be understood that tacking is slow work, and a greater distancemust be traveled than would be covered by a power-boat, which would beable to go in a straight line. However, with wind-propelled craft thisis the only way in which progress can be made against the wind. Theleft-hand side of a yacht viewed from the stern is called the port side, while the right-hand side is called the starboard side. Thus a yachtsailing with the wind blowing on her port side is on the port tack, while if the wind is blowing on the starboard side she is said to be onthe starboard tack. From this the reader will see that Fig. 142 shows animpossible case. 

[Illustration: FIG. 142]

[Illustration: FIG. 143]

[Illustration: FIG. 144]

[Illustration: FIG. 145]

The sails in front of the mast that are placed nearest the stern of theyacht act in such a manner as to turn the bows in the direction of thearrow, as illustrated in Fig. 146, and the sail or sails abaft the mastturn the boat in the direction of the arrow _A_. The boat thus revolvesupon the center of the mast much as a weathercock revolves upon itspivot. If there is more than one mast, all the sails carried abaft themainmast serve to turn the boat in the direction _A_. The work ofsailing depends greatly upon the skill in balancing these two effects sothat the boat will progress in a straight line. To do this the sails areset in a greater or less angle in relation to the center line of theboat. The less the angle that a sail makes with the center line of theboat, the greater is its power to determine in which direction the boatwill steer. The more the yachtsman slackens out his jib and foresail, orthe smaller he makes these sails, the less their power will be to turnthe boat in the direction _B_. On the other hand, the larger they areand the more tightly they are pulled in, the greater will be theirpower. When the mainsail and all of the sails abaft the mainsail areslackened out and the smaller they are made, the less their power willbe to swing the boat in the direction _A_. 

The influence of a sail upon the speed of a boat also increases with theangle that it makes with the center line of the hull. The more theyachtsman slackens out his sail, the more it will help the boat along. The reader will see that these two conditions interfere with each other, and therefore the trimming of the sails becomes a compromise. It is goodfor the young yachtsman to remember to sail his boat with the sails asslack as possible, as long as she keeps a good course. He should alsoremember not to overload her with sails, since the nearer to an uprightposition she maintains the faster she will go. 

It is not possible to depend entirely upon the trim of the sails to keepa model in a given course. This is because the strength of the windvaries so that the sails are in balance one moment and out of balancethe next. The sails abaft the mainmast overpower the sails before itwhen the wind increases. The result of this is that the bow of the boatwill be repeatedly turned in the direction _A_, Fig. 146. 

[Illustration: FIG. 146]

[Illustration: FIG. 147]

[Illustration: FIG. 148]

Some form of automatic rudder is therefore generally used to overcomethis tendency of the yacht to "luff" in the wind. Fig. 147 shows thecourse of a yacht reaching from _A_ to _B_. The dotted lines show thecourse she should follow. The full line shows the effect of puffs ofwind, which repeatedly take her out of her course. Many times she maycompletely turn around and make a similar course back to thestarting-point, as in Fig. 148. There is also the danger of her beingtaken back when pointing directly against the wind--the wind will forceher backward stern first for some distance, as illustrated in Fig. 149. She will do this until she manages to get around on one tack or theother. 

The dotted line _B_ illustrates the course in which she would be drivenunder these conditions. It is not practical to sail a model yacht deadbefore the wind without an automatic rudder. With the use of anautomatic rudder the erratic movements shown in Fig. 148 can be entirelyovercome. The action of the rudder is such that every time the boatleans over to luff up into the wind, the weight of the rudder causes itto swing out, and thus prevents her from losing her course. As adifferent type of rudder is required, according to the course in whichthe yacht is sailing, the weight should be adjustable if the same rudderis used. 

[Illustration: FIG. 149]

[Illustration: FIG. 150]

[Illustration: FIG. 152]

Let us consider scudding before the wind. For scudding the heaviestrudder should be used, or the weight on a loaded tiller should be in itsposition of maximum power. All the sails abaft the foremast should beslackened out as far as they will go, which will bring the booms almostat right angles with the center line of the boat. If the craft is acutter or yawl with a light weight, the yachtsman should rig thespinnaker. The head-sails may be left slack or can be tightened. Fig. 150 shows the position of the booms when scudding with a schooner andyawl. The yawl is shown scudding goose winged. The cutter is illustratedwith the spinnaker set. The other craft is a two-mast lugger withbalanced lugs. 

[Illustration: FIG. 151]

Attention is now directed to "reaching. " For this particular work theyachtsman should put on a medium rudder. When using a weighted tillerthe weight should be put in a midway position. The head-sails should bepulled in fairly tight and the aft-sails made slack. The yachtsman, however, should not slacken them as for scudding. Fig. 151 shows aschooner reaching. The thick black lines represent the booms of thesails. If the wind is very light a spinnaker-jib may be set or ajib-topsail in light or moderate breezes. In the case of a wind thatcomes over the stern quarter, as indicated by the arrow _A_, the nextheavier rudder, or its equivalent in weighted tiller, should be put inoperation, and the sails slackened out a little more than before. Theboat is then said to be free and sailing on the starboard tack. If thewind is coming in the direction _B_ the jib and foresail may requireslackening and the aft sails pulled in more than when sailing with thewind in the direction _C_. A still lighter rudder can be used as thecourse gets near to beating windward, and the yacht is said to beclose-hauled on the starboard tack. 

In beating to windward, if a rudder is used at all, it should be aslight as possible, just heavy enough to keep the boat steady. However, this is just the condition of sailing when a boat can dispense with arudder. It depends entirely upon the characteristics of the particularyacht being sailed, and for this the yachtsman must depend upon his ownexperience. The jib-topsail should not be used in a case like this, andif the wind is fairly strong a smaller jib should be set than that usedfor reaching. It is advisable to slacken the jib and foresail out andpull the aft-sails in somewhat tightly. Fig. 152 shows a cutter beatingto windward on a port tack. In this case she will have to pay out tostarboard a bit before her sails fill. 

In sailing the weather must be watched very closely, and the amount ofsail carried will depend entirely upon the weather conditions. A yachtshould never be overloaded with sail. If she has more than she cancomfortably carry she will heel over and drag her sails in the water. Not only this, but she will also drift to leeward when beating towindward. When sailing a new boat, her best trim for various points ofsailing and force of wind must be found by painstaking experiments. Theboat should always be sailed with her sails as slack as she will takethem and keep in her course. In this way she will move faster than whenthe sails are pulled in close. 

The model yachtsman should always watch the wind and note whether itshifts its direction or alters its force. The boat is trimmedaccordingly when the boat is put about. Easing or tightening the jib ormain-sheet slightly will make a very noticeable difference. 

By taking down the top-sail or setting a jib-head top-sail in place of ajack yard top-sail, the yacht will be caused to ride easier in puffs ofwind. In case she does not point well to windward when beating, theyachtsman should try a smaller jib, or he can slacken theforesail-sheet. If she runs off regularly to leeward on one tack only, while keeping well to windward on the other, she has some defect inconstruction or a bent keel. 

CHAPTER XIV

TWO-FOOT SAILING YACHT

THE model yacht described in this Chapter is the design of Mr. W. J. Daniels, of England, and was described by him in "Junior Mechanics. " Mr. Daniels is one of the best known and most successful English designersof model yachts, and the one here described can easily be constructed bythe average boy:

 In order that the reader may realize the obstacles to be surmounted in designing a model yacht that will sail in a straight line to windward, irrespective of the different pressure that the wind may expend on the sails, it must be pointed out that the boat is continuously altering the shape of the submerged part of her hull: therefore, unless the hull is so designed that harmony is retained at every angle to which the pressure of wind on the sails may heel it, the model's path through the water will be, more or less, an arc of a circle. Whether the boat sails toward the wind, or, in other words, in a curve the center of the circle of which is on the same side of the boat as the wind, or in a curve the center of the circle of which is on the opposite or leeward side, will depend upon the formation of the boat. 

 As these notes are intended to first initiate the reader into the subject of model yacht building and construction, the design supplied is one in which all things, as far as shape is concerned, have been considered. 

 It is the endeavor of every designer to produce the most powerful boat possible for a given length--that is, one that can hold her sail up in resistance to the wind-pressure best. Of course, the reader will easily realize that breadth and weight of keel will be the main features that will enable the model to achieve this object; but, as these two factors are those that tend to make a design less slender, if pushed to extremes, the designer has to compromise at a point when the excess of beam and buoyancy are detrimental to the speed lines of the hull. 

 But the question of design pure and simple is a complex one, and we do not intend to weary the reader just now with anything of that kind, so we will now proceed to build the hull. In order that we may correctly interpret the shape shown in the design without being expert woodcarvers, we must use our ingenuity and by mechanical means achieve our object, at the same time saving ourselves a large amount of labor, such as we should have to expend if we made this boat from a solid block of wood. 

 Now, as regards understanding the drawings: it is essential to remember that a line which in one view is a curve is always a straight line in the other two views. Those lines which are drawn parallel to the water-line are known as water-lines, and it will be seen that the curves shown on the deck plan represent the actual shapes of the hull at the corresponding water-lines above, below, and exactly on the load water-line. In other words, if after the hull is made it were sunk down to these various levels, the shapes of the hole made in the surface of the water would be as shown in the plan. 

 Therefore, instead of making our boat from a solid block of wood, we will make our block up from several layers, the thickness of each layer being equal to the space between the water-lines; but before gluing these layers together we will cut them out to the exact shape that the boat will be at their various positions. 

 It will not be necessary to have a separate piece of wood for each layer, as some layers below the actual water-line will be cut from the pieces of wood that have been cut out from the layers above. 

 In this case, the boat being 24 inches long, the top layer will be the same length and breadth as the boat, and 1 inch in thickness. 

 Draw down the center of the board a straight line, and other lines square to it, representing the position of the cross-sections as shown in the drawing. You have now to transfer the deck line to this board, and this is done by marking the breadth at the various sections and drawing a curve through the spots, a thin strip of straight-grained wood being used as a rule, the latter being held down by such weights as are available. For the purpose of laying off the water-lines truly, lines spaced at 1-1/2 inches are shown; the first, it will be noticed, is half a section or 3/4 inch from the stem head. 

 The material required will be a board of pine about 6 feet long, 8 inches wide, and 1 inch finished thickness. 

 Nearly all wood-yards stock first-quality pine, but it is in planks 3 inches thick. You can no doubt pick up a short length about 4 feet long. 

 If so, take it to a sawmill and have two boards 1-1/4 inches thick cut and then machine-planed down to a dead inch. Perhaps you can purchase a board that is already cut, and is fully 1 inch thick, to allow for planing. 

 Prepare one edge of the board straight with a plane, seeing that it is square to the surface. 

 As a planing-machine always leaves a series of ridges across the board, varying according to the quality of the machine, it is necessary before transferring the lines to the wood to just skim the surface with a nicely sharpened plane, and set so as to just skim the wood. 

[Illustration: FIG. 153]

 The lengths required are: _A_, plank 24 inches long; _B_, plank 24 inches; _C_, plank 18-1/2 inches. 

 The _D_ plank will be cut from the center of _B_, but will have to be shifted two sections forward. 

 Having transferred the various shapes from the drawing on to their respective layers, you saw out each carefully with a bow or a keyhole-saw, care being taken not to cut inside the lines. It is better to cut full, and trim down to the lines with a chisel or plane. A good deal of trouble can be saved by the expenditure of a few cents for having them machine-sawed, in which case ask the sawyer to use his finest-toothed saw. 

 Having cut out layers _A_, _B_, _C_, and _D_, fresh lines are marked, as shown by the dotted lines in the plan. These indicate the shape of the inside of each layer when the boat is carved out, and save labor. 

 These may as well be sawed out now as carved out later. It will also facilitate gluing up, as it will allow the superfluous glue to be squeezed out, and also decrease the breadth of the joint. 

 In order to get these various layers glued together dead true to their positions as indicated in the design, you must choose a section about amidships, say section 11, and with a square draw a line from that section, which is, of course, still showing on the surface of the layer, down the edge on either side, joining up with a line across the opposite face. Also vertical lines at each end of the midships line must be drawn on the wood, great care being taken to get the midships line on the under face of the layers dead opposite each other. 

[Illustration: FIG. 154]

[Illustration: FIG. 155]

 If your outfit contains half a dozen carpenter's hand screws, these can be used; but if not, it will be necessary to purchase from a hardware store eight seven-inch bolts and nuts 3/8 inch in diameter, with one washer for each, and to make up four clamps, as shown in Fig. 156. 

[Illustration: FIG. 156]

 You will start by gluing layer _C_ to layer _D_, blocks being placed between the surface of the layers and the clamps to prevent bruising the wood. These two are then glued to layer _B_, and when this is thoroughly set they are glued to the layer _A_. The best glue to use for this job is marine glue, which does not dry too quickly, and so gives plenty of time to see that the layers have not shifted. In every case one clamp should be placed at each extreme end of the shorter layer, so as to insure the ends making contact, the other two being placed equidistant. 

 While waiting for the glue to set, you can be preparing the four layers (shown below _D_) for the lead keel pattern. The lines must be cut out, in this case, with a chisel, as it will be noticed that the lower faces must be left wide enough to receive the top face of the layer beneath it. 

 It will be noticed that the under face of each of these layers extends beyond the top face aft, and allowance must be made for this. On laying off the lines on the fin layers, do not join up with a point each end, but leave about 1/8 inch thickness, as shown on the drawing. 

 These layers must be drilled through to take the keel-bolts, which are made from two motorcycle spokes, twelve-gage. These should be cut to a length of 5-1/2 or 6 inches. Great care should be taken to insure that the midship lines are exactly vertical over each other when these layers are glued up. 

 Before gluing these four layers on to the hull proper, they should be held in position by means of the spokes, in which position they can be sawed to shape for the keel pattern. First, with a small plane or sharp chisel cut down roughly, then a rasp and different grades of sandpaper are used, working across the joints. 

 It will be realized that, if the pattern for the keel were cut off dead on the line indicated on the design, there would be a loss of wood through the saw cut. In order to obviate this, another line 3/16 inch below the proper lead line is drawn, and the saw cut made between these two lines. You will now plane down each face that is left rough by the saw, straight and square to each of these lines. On the top face of the pattern for the lead, glue or tack a piece 3/16 inch thick along the face, and cut down the edges flush. 

 You will by this means have made up for the amount of wood carried away by the saw. You will no doubt find a difficulty in holding the pieces of wood for planing in the ordinary way, but it is simple enough if you set the plane nicely, grip it in a vise or bench screw upside down, and push the work over the plane's face, instead of vice versa. But be careful of your fingers!

 Take the pieces left from the spokes when cutting down to length, and put these in the holes in the keel pattern. These are for cores, and if you take your pattern to a foundry they will cast it for a small amount, with the holes in it. 

 Shoot the top face of the lead in the manner before described, and fit on. The hull is now ready for carving out. Screw on your bench two pieces of wood about 18 inches in length and 4 inches wide, so that they project over the edge of the bench about 10 inches. These should be about 15 inches apart. Place your hull upside down on them, and fix it by nailing upward into the top layer. After cutting off the corners of the layers roughly with a chisel you use a small plane set fairly fine, and work all over the hull evenly, taking care not to cut below any of the joints. A small gouge will be required to clear the wood from the region of the after fin, a round rasp--sandpaper being wrapped around a small stick--being used for smoothing down afterward. 

 Templates of the cross-sections should now be made from thick white paper. This is done by pricking through the design to transfer their shape onto the paper. The cross-sections have on this account been produced here actual size. If cross-lines representing the water-lines are drawn, you will have an excellent guide for fitting, as these lines will, of course, come opposite each glued joint. 

 Try your templates now and again as you work, and do not try to finish one spot, but keep the whole at an even stage, and you will see the hull gradually grow into shape. 

 The topsides (which is the name given to that part of the vessel's hull above the water-line) are responsible for the boat's appearance when afloat, and until the top sheer is cut off the boat looks very disappointing. The cross-lines being still on the upper layer, draw square lines from them down the topsides and from the drawing mark the points through which the sheer-line runs. The thickness of the deck must be allowed for, and as this will be just over 1/16 inch, the line must be drawn this much below the finished sheer-line. The arch of the transom must be marked, and the hull cut down to the sheer. To avoid the risk of splitting, a number of fine saw cuts are made down each section line and two or three at the transom. 

 You now proceed to carve out the inside. Pad your bench bearers and rest your hull upon them. A curved wood gouge with a fairly flat edge is the best tool. Get it nicely sharpened, and work all over the inside of hull until it is about 3/16 inch thick, the top edge being left 3/8 inch wide. 

 Keep holding up to the light until it is showing a blood-red color, and smooth down the gouge marks with coarse sandpaper. 

 The hole for the stern-tube must now be drilled, and the tube made and fitted. The hole should be 1/4 inch in diameter. First drill a smaller hole, and then with a 1/4-inch rat-tail file slowly open it out, at the same time rubbing a groove down the stern-post. The stern-tube is made from a piece of light-gage brass tube, it being cut away with a piercing saw to leave a strip the length of the stern-post. Drill three holes in the strip at equal distance and large enough to take a 1/4 inch brass screw, No. 0 size. Temporarily screw the tube in position, and from a piece of thin brass make a plate for the inside. An oval hole will have to be made in the plate to enable it to seat flat over the tube. Solder this while in position. Then remove the whole, and replace, after white-leading where wood touches brass. 

 The deck-beams, three in number and 1/4 inch square in section, must now be fitted. The sheer edge which we left 3/8 inch wide must be recessed to receive the beams, the recess being made with a 1/4-inch chisel. 

 Before gluing beams in, three coats of good varnish must be applied to the inside of shell. 

 The deck should now be prepared and fitted. You will require a piece of pine of ample length and breadth, 1/8 inch in thickness, and after planing finely and sand-papering, pieces of the same stuff should be glued on the under face to reinforce it where the bowsprit, keel-plate, hatch rim, and mast will be fitted. Cut these pieces to shape before gluing on. 

 Before doing the latter, apply a coat of clear size to the upper face of the deck; this will bring up the grain, so paper it down when dry. This process should be repeated three times. 

 Three coats of varnish should be given to the under side of the deck after the pieces have been glued on, and when dry the deck can be fitted, 3/8-inch veneer pins being used for fixing on, and care being taken to get it true to position. A center line is drawn down the under side of the deck, and marks made to correspond at the stern and transom on the shell. 

 The planking lines on the deck can be drawn to suit your fancy, India ink and a draftsman's ruling pen being used to do it, afterward applying two coats of carriage varnish. 

 To paint the hull, white lead and dryers, in the proportion of 5 to 1 by weight respectively, should be dissolved in turpentine, a few drops of linseed oil being mixed to make it work freely. Have this about the consistency of milk, and, after straining, give the hull about eight coats, one every twenty-four hours, rubbing each down when dry with No. 00 sandpaper. Keep the joint representing the load water-line always in sight by penciling over after each coat of paint is dry. When a sufficient body of paint has been applied, the colors can be applied. Enamel is best for this. Stick strips of gummed paper around the hull at the water-line, and paint up to the edge. When the paint is dry the paper can be soaked off, the paper being again applied, but reversed for the other color. If you can use a lining brush the paper is not necessary for the second color. 

 While the painting is going on, spars, sails, and fittings can be made. As the spars have to be varnished, it is best to make them first. Pine should be used, and after cutting strips of suitable length and diameter, plane them square in section. With the batten draw on the face the amount of taper to be given, and plane down to this line, still keeping the spar square in section. This having been done, the corners are planed off carefully until the spar is octagonal in section, when it is easy to make it perfectly round with sandpaper by rubbing with the paper rolled around the stick. The diameter of our mast is 1/2 inch parallel until the hoist of the fore triangle is reached, tapering from there to 1/4 inch at the masthead or truck. The boom is 1/4 inch at the gooseneck, thickening to 3/8 inch where the main-sheet is attached, down to 1/4 inch at the outboard end. The jib-boom is slightly less than 1/4 inch parallel. 

 All spars should be treated with clear size and fine sandpaper before varnishing. This will prevent discoloring by the latter, and will also allow the India ink markings to be made, which latter will be a guide for the trimming of the sails. 

 In order that any yacht, model or otherwise, may be able to perform her best, it is essential that she should have well setting sails. In fact, in a model a badly setting sail will sometimes even be enough to prevent her going to windward at all. By well setting sails we mean sails that are naturally flat and not made so by straining them out on the spars. Light material, such as cambric or light union silk, is best for this purpose, but not a material that has any dressing in it. 

 This particular sail plan is very easy to mark out. Lay your material out on a table or smooth surface and pin it down with drawing-pins, sufficiently stretching it so as to pull out any creases. The length of the back edge of the mainsail (which is called the leech) is measured off 1-1/4 inches inside the edge of the cloth, and a curve struck as illustrated. The other two sides of the mainsail are then laid off and pencil lines drawn. You will note that allowance must be made for hemming the back edge of the mainsail. If your sewing-machine has a hemmer, find out how wide a hem it makes (the smaller the better), and make allowance accordingly, twice the width of the hem being necessary. Much depends upon the tension at which the machine is set, so be careful that the latter is sufficiently slack so that it does not draw up the material. 

 The jib is marked out in the same manner, and, as illustrated, the lines representing the positions of the batten sleeves are drawn. The batten sleeves are small pockets into which thin pieces of cane (called battens) are inserted to help the sail to set nicely. Unless the sail is a good cut to begin with, however, the insertion of these battens will never make it right. The sails should now be cut out with a sharp penknife or scissors, care being taken not to pull the cloth, and especially not along the edges that run across the threads. You then hem the backs and also the foot of the jib. The batten sleeves (which should be of white satin ribbon about 3/8 inch in width) should now be sewn on by stitching down along the extreme edge to the line drawn, and then down the other edge, the ends being left open. A strip of narrow tape is sewn across the foot of the jib-sail to take the strain of the pull, the part of the jib contained by the curve of the foot and the tape being known as the bonnet of the jib. 

 To prevent the edges of the sails (other than those hemmed) being stretched, you bind them with good tape. The tape is first folded and creased by rubbing over an edge. The end of the tape is then turned in. Take a corner of the sail and place it inside the fold of the tape, care being taken to get the raw edge right up against the crease. The needle of the machine should then be lowered through it as near to the edge of the tape as practicable, taking care that it goes through both edges. Keeping a slight pull on the binding, arrange the cloth in it without pulling the edge. Put the foot of the machine down and sew it, afterward raising the foot again and proceeding as before right around the raw edges of the sail, leaving the needle down each time the foot is raised. Do not sew where a batten sleeve passes under the binding, as you will require the former left open to allow the batten to pass into the fold of the binding. The rings for putting up the luffs of the jib- and main-sail are made by winding a piece of thin brass or German silver wire around a steel rod (the spokes used in the keel being suitable for the latter) and sawing down to divide them. A small eyelet should be put in each corner of the sails, and others spaced evenly at about 2-1/2 inches apart along the boom and about 5 inches apart along the mast, for lacing on. An extra row of stitching may be run down the outer edge of the binding to smooth it down. 

 The simpler the fittings of a model that is required for practical sailing, the better. They should be as light as practical. Aluminum is not advisable for fittings when the boat is to be sailed in salt water. 

[Illustration: FIG. 157]

 The bowsprit fittings, which are known as the gammon iron and heel plate (Figs. 157, 158), are made by soldering pieces of brass tube (cut to suitable size and shape) onto pieces of triangular sheet brass, as illustrated. The horses can either be of wire with the ends turned to suitable shape and fitted with one screw, or they can have plates for two screws, in which case the wire is either threaded and screwed into the plate or silver-soldered to it. Silver-soldering is done with a blow-pipe. The flux used is borax made into a thin paste with water. Silver-solder is bought in small sheets, and a few cents' worth will go a long way if used properly. Cut small pieces about 1/8 inch by 1/16 inch, and, after painting the part to be soldered with your paste borax with a very small brush, pick up the solder with the tip of the brush and put it in position. It will then run around the joint when the metal is raised to sufficient heat. 

[Illustration: FIG. 158]

 The hatch-rim is made by cutting a strip of thin brass 1/4 inch in width, the length being the circumference of the oval. The two ends are brought together and silver-soldered. Cut out the oval in a piece of very thin brass and fit in your oval strip so that the flat is just in the center of it. This can then be sweated around with an ordinary soldering-iron, the flat being trimmed down afterward with the shears to leave a flange 1/4 inch in width, the latter being drilled to take 1/4 inch No. 0 round-head screws. 

[Illustration: FIG. 159]

[Illustration: FIG. 160]

[Illustration: FIG. 161]

 The deck fitting for the mast, (Fig. 159) is made in much the same way, a piece of tube being used instead of cutting a strip of brass. To receive the heel of the mast a fitting known as the mast-step must be made and fitted. This, of course, must be done before the deck is put on. The step is made from two pieces of brass, each about 1/32 inch in thickness, 1 inch long and 1/2 inch wide. One is hard-soldered on edge down the center of the other to form something like a T girder. A slot, as illustrated, is cut in the upright piece with a ward file, and holes drilled in the flat for screwing down on the inside of the boat. A ferrule of brass tube is fitted to the heel of the mast, a cut of suitable size being made in it to receive the upright of the step. A hole should be drilled through the heel of the mast at right angles to the slot, and a wire passed through and riveted, the latter being of suitable thickness to be received by the slot in the step. 

[Illustration: FIG. 164]

[Illustration: FIG. 163]

[Illustration: FIG. 162]

 The rudder-blade (Fig. 162) is made from a piece of sheet brass fitted to a tube, the latter being an easy fit into the stern-tube already fitted. The blade can be soldered onto the tube. The pintle on which the rudder fits and swings is a strip of brass, the width of the after fin, a wire pin being hard-soldered in to fit up into the rudder. 

 The pintle (Fig. 163) should be fitted before the painting is started. 

 In the steering gear, instead of a quadrant, as the fitting on the rudder-head of the "Braine" gear is called, you fit an ordinary tiller (Fig. 164) by bending a wire to suit your fancy and soldering it on to a collar made from a piece of tube that will just sleeve on the outside of the rubber-tube, which latter is fixed by drilling a hole right through it and the rudder head, and fitting a tapered pin. 

[Illustration: FIG. 165]

[Illustration: FIG. 166]

 The steering-gear rack (Fig. 165) by which the amount of helm is adjusted is made from a strip of brass cut with lugs which are bent up at right angles as illustrated. This need only be of thin sheet metal, as the strain is very small. 

 For running before the wind, separate lines are used, two in number, as illustrated, and the amount of helm is governed by the distance away from midships that the lead is moved. For instance, if the lead is placed amidships, the pull will simply keep the rudder dead straight, whereas if placed on the deck edge it will allow the maximum amount of angle. 

 Your bowsers can be made from pieces of toothbrush handle or from brass or German-silver wire. Very efficient bowsers can be made from aluminum tube cut in sections about 3/16 inch long, with three holes drilled in each piece around its periphery. 

 Plaited bobbin cotton should be used for the cordage, as it does not curl up when wet. 

 If you decide to fit the Braine steering gear, a spur or bumpkin, as it is termed, must be fitted to take the rubber centering line. 

APPENDIX

BOYS' DICTIONARY OF MARINE TERMS

 =Abaft. = Behind; toward the stern. 

 =Abeam. = At right angles to the side and in horizontal plane. 

 =Aft. = Toward the stern. 

 =After-body. = Between amidships and stern. 

 =Aloft. = Overhead; on the yards or in the upper rigging. 

 =Amidships. = The middle part of a vessel. 

 =Anchor. = Instrument for holding vessels at rest in the water. Made of iron. 

 =Athwart. Athwartships. = Across; from side to side. 

 =Ballast. = Material used to load the ship, for stability or submerging purposes. 

 =Barge. = General name for vessels built for towing. 

 =Bark. = Three-masted vessel, square-rigged on the fore- and main-masts, and fore-and-aft rigged on the mizzen. 

 =Barkentine. = Three-masted vessel, square-rigged on the foremast and fore-and-aft on the main-and mizzen-masts. 

 =Beam. = The widest part of a vessel. 

 =Bollards. = Posts of timber on sides of docks, quays, etc. , over which ropes are thrown for hauling vessels alongside. 

 =Boom. = The lower spar for a fore-and-aft sail. 

 =Bow. = Sides of fore part of boat: the right hand being the starboard bow, and the left hand the port bow. 

 =Bowsprit. = Pole projecting from stem forward, and taking forestays and bobstays. 

 =Bridge-house. = House built near bridge. 

 =Brig. = Vessel with two masts, both square-rigged but having a gaff mainsail. 

 =Buoy. = A floating object moored over a certain spot; generally a warning of danger. 

 =Buoyancy. = The capacity for floating which a boat possesses. 

 =Cabin. = Room for use of officers and passengers. 

 =Capstan. = Consists of a long drum revolving vertically and used for pulling in heavy lines. Sometimes used in connection with windlass to hoist anchor by hand. 

 _Center of Gravity. _ Center of weight. 

 =Coaming. = Raised planking around hatchway of yacht to prevent water shipped in rough weather from getting below decks. 

 =Cockpit. = Formerly an apartment under lower gun-deck of warship, used as quarters for junior officers, and during a battle devoted to the surgeon and his assistants. 

 =Cockswain. = Person who steers a boat. 

 =Compass. = Instrument composed of one or more magnetic needles attached to a circular card which turns freely on the point of a steel cone or floats on a liquid. The upper surface of the card is divided into the 32 points of the compass. Used to find direction. 

 =Craft. = Usually denotes small size vessel, but may be applied to any kind. 

 =Crane. = Machine for hoisting and moving heavy equipment and material. 

 =Cruiser. = Boat intended for extended voyages. Used in connection with yachts, to distinguish from racing models. 

 =Davit. = Light crane on side of ship for lowering and lifting boats. Sometimes applied to projecting beam over which anchor is hoisted. 

 =Displacement. = Weight of ship and all on board when at sea. It is equal to the weight of the water displaced. 

 =Dock. = An excavation of large area for reception of vessels. Wet-dock for loading and unloading or dry-dock for building and repairing vessels. 

 =Dock-yard. = A place where ships are built and repaired. 

 =Funnel. = Large sheet-iron tube extending from the uptake high above the deck, through which smoke and gases pass. 

 =Galley. = The kitchen of a vessel. 

 =Gangway. = Sides of upper deck from main-mast to mizzen-mast, or from the former to the break of a poop or raised quarter-deck; also a passage for entering or leaving vessel. 

 =Gross tonnage. = Entire cubical capacity of ship, including every inclosed space and all room under deck from stem to stern-post, if closed in and usable. 

 =Gunwale, gunnel. = Upper part of sheer-strake, where it comes in contact with upper deck stringer. 

 =Headlights. = Lights carried at the masthead. 

 =Head of the bowsprit. = The forward end. 

 =Hull. = The entire structure of a vessel, exclusive of equipment. 

 =Inboard. = Within the ship. 

 =Inner skin. = Planking or plating covering the inside of frames. 

 =Jack. = Name given to various sails, ropes, etc. 

 =Jib. = Triangular sail carried on a stay reaching from the foremast head or from topmast to the jib-boom. 

 =Keel. = Backbone of a vessel in wooden ships. Composed of great lengths of timber connected to each other by scarfs. In steel ships usually a set of plates from stem to stern. 

 =Even keel, uneven keel. = Designates the manner in which ship floats. If balanced evenly in a fore-and-aft direction she is on even keel, if depressed at head or stern she is on uneven keel. 

 =Keelson angle-bar. = Any angle-bar used in the construction of a keelson. 

 =Lanyards. = Short lengths of rope used to tighten up davit-guys, awnings, etc. 

 =Launching. = Sliding a boat into the water from the building-berth. 

 =Lee side. = Opposite to the side on which the wind blows. 

 =Lighter. = Large craft used to bring cargo alongside or to lighten a grounded vessel. 

 =List. = When one side of a vessel lies deeper in the water than the other; caused by shifting cargo, etc. 

 =Log. = Apparatus used to determine speed of a vessel. 

 =Main-mast. = Principal mast of a ship; the second mast counting from bow to stern. 

 =Marine engine. = Engine especially designed for the propulsion of boats. 

 =Mast. = A long piece, or system of pieces, of timber, placed nearly perpendicularly to the keelson of a vessel to support the spars and gear by which the sails are set. In modern practice, steel masts are built by riveting rolled plates together. 

 =Midships. = Middle part of a ship. 

 =Mizzen-mast. = Third mast on a vessel with three or more masts. 

 =Mizzen-sails. = Sails carried on a mizzen-mast. 

 =Mushroom Ventilator. = Short cast-iron tube with movable iron rod passing through the center. A metal cup is fitted to the top of the rod, which may be lifted to permit air to enter, or closed to prevent water from entering. Generally fitted over cabins. 

 =Navigation Bridge. = Bridge used for taking observations or handling the ship in difficult situations. 

 =Outboard. = Outside the hull or beyond the gunwale. 

 =Outlet cock. = Any cock used to free a receptacle of water. 

 =Paddle-wheels. = Wheels fitted on each side of a paddle steamer in connection with the paddle-shaft, consisting of a cast-iron boss from which wrought-iron arms radiate, strengthened by rims and stays, and with a float attached to each arm. 

 =Pawl. = Small catch to prevent moving object from going beyond certain limit. 

 =Pile. = A piece of lumber or iron, together with others, driven into the bed of a river for the support of a pier, bridge, etc. 

 =Pilot Bridge. = Narrow thwartships platform, extending from side to side above a steamer's upper or bridge deck. Serves as a station for the pilot or officer of the watch. 

 =Port. = Opening in ship's side, in bulwark, etc. 

 =Propeller-screw. = Propeller in which blades are at an angle to the line of axis, similar to the threads of a screw. 

 =Quarters. = Men's positions when called to their duties, as during fire or boat drill; also living accommodations. 

 =Quay. = Artificial landing-place. 

 =Raft. = A collection of boards fastened together by ropes or chains, and capable of floating. 

 =Ram. = Massive projection under water at the bow of a warship. The ship is also called a ram. 

 =Rat-line. = Three-stranded cord, of which the ladder-like steps in lower rigging, topmast rigging, etc. , are formed. 

 =Rigging. = Entire equipment of a ship's masts, spars, etc. , with their standing and running ropes. 

 =Rudder. = A device for steering vessels. Hinged to the outside of the hull, usually at the stern. 

 =Sail. = A device of canvas and rope fastened to spars and rigging, and extended to catch the wind and drive the vessel. 

 =Skiff. = Long, lightly built boat sometimes used in rowing races. 

 =Sloop. = Vessel with one mast, having a jib-sail. 

 =Spar. = Any shaped piece of timber used as a mast, bowsprit, yard, etc. , or intended for such use. 

 =Stanchion. = A stationary upright support. 

 =Superstructure. = Any structure above top full deck. 

 =Tack. = To change the direction of sailing due to wind. 

 =Thwart. = Seats are called thwarts when they extend from side to side of a boat, athwart when across. 

 =Tonnage. = Entire capacity or cubical contents of a vessel. One ton estimated at 100 cubic English feet. 

 =Trawler. = Fishing-vessel with ground-sweeping net. 

 =Trim. = Term indicating the state of a ship with regard to ballast; position of a vessel in the water with respect to horizontal. 

 =Turtle-back. = Top of wheel-house, forecastle, etc. , formed like a turtle's back. 

 =Upper Works. = Same as freeboard when a vessel is loaded. 

 =Uptake. = Part connecting smokebox to funnel. Sometimes includes the smokebox. 

 =Ventilator. = Usually made of sheet iron in tubular forms, and arranged to expel foul air and permit the passage of fresh air to any part of a ship. 

 =Vessel. = Craft requiring a licensed master. (Boats do not). 

 =Water ballast. = Sea water let into double bottom or ballast-tank. 

 =Water-Line. = (Light) Submerging line of vessel without cargo. 

 =Water-Line. = (Load) Submerging line of vessel with full cargo. 

 =Water-tight Compartment. = Compartment with water-tight bulkhead at each end. 

 =Winch. = Machine used for loading or unloading cargo. Some are hand driven and some electrically driven. 

 =Windlass. = Special form of winch used to hoist anchor. 

 * * * * *

Transcriber's Notes:

Obvious punctuation errors repaired. 

Page 128, "oppositite" changed to "opposite" (the opposite end of)

Page 131, N italicized to match rest of usage (center of the disk _N_)

Page 132, D italicized to match rest of usage (to the _D_ valvepreviously)

Page 185, "deterimental" changed to "detrimental" (detrimental to thespeed)