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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 speed
for 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 born
in the race. The little three-year-old chap is instinctively attracted
by a puddle of water in which to sail his "boat," which may take the
form of a piece of shingle or common board. Few men have passed through
their boyhood days without having built boats at some time.

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

This book is the result of that vow, and the author earnestly hopes that
it 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 sees
his little model steamer proudly make her way across the park pond, or
his little sail-boat respond to the summer breeze.

The author takes this opportunity to thank his wife, who acted as his
amanuensis 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 boats
described in this book, it will be well for the young boat-builder to
become acquainted with such terms as buoyancy, displacement, center of
gravity, etc. Knowledge of these subjects is more or less necessary if
successful boats are to be made. Aside from this, they are terms that
every boy who claims an interest in boats should understand.

"How does a steel boat float?" is a question that many boys ask. The
reason they usually designate a steel boat is probably because steel is
so much heavier than water. But many things heavier than water can be
made to float if they are in the form of a boat. Concrete, for instance,
is now being used in ship construction, and this substance, when
reinforced 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 that
gives a body "weight." Some substances are heavier than others; or, to
be more correct, it is said that the specific gravity of one substance
is greater than that of another. It will be well to keep in mind that
specific gravity merely refers to weight. It is simply a scientific
term. The specific gravity of a substance is always expressed by a
figure that tells how much heavier any substance is than water, because
water has been chosen as a standard.

The specific gravity of water is 1. The specific gravity of gold is
19.26, meaning that it is about 19-1/4 times heavier than water. The
specific gravity of a piece of oak is 0.86, which shows that it is not
quite 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 x
62.42, because it is 19.26 times heavier than water. A cubic foot of
oak, however, would weigh only 54 pounds, because it has been found that
it 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 float
when placed in water. The cubic foot of brass (_B_), however, will not
float, 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 in
water, but that substances heavier than water, such as iron, lead, gold,
silver, etc., will not float. If the cubic foot of oak (_A_) were
placed in water, it would sink to the depth shown at _C_. When the block
sinks into the water, a certain amount of water will be forced away or
"displaced"; that is, the block in sinking occupies a space that was
previously occupied or filled with water. The oak block sinks to within
a short distance of the top because the oak is really just a trifle
lighter than water. If a pine block were placed in the water it would
sink only to the distance shown at _D_, since the weight of pine is less
than 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 of
the block out of the water. Thus, it will be seen that for a given
volume (size) a cubic foot of wood will sink to a depth corresponding to
its weight. Different kinds of wood have different weights.

If a cubic foot of brass is placed in water, it will sink rapidly to the
bottom, 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 is
rolled or flattened out in a sheet, and formed or pressed into the
shape of a boat hull, as shown in Fig. 2, it will float when placed upon
the surface of the water. Why is it that brass is caused to float in
this 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 float
because 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 of
water actually displaced by the hull could be weighed, it would be found
that the weight of the water would be greater than the weight of the
hull. It will be understood that the space occupied by the brass
boat-hull is far greater than the space occupied by the block of brass
before it was rolled out and formed into a hull. What is true of brass
holds true of iron, steel, etc. A block of steel will not float, because
the water it displaces does not weigh nearly as much as the block. If
this block, however, were rolled out into a sheet and the sheet formed
into a hollow hull, the hull would float, because it would displace a
volume of water that would more than total the weight of the steel in
the hull.

In the case of the brass boat-hull, it would be found that a greater
portion of the hull would remain out of the water. The hull, then, could
be loaded until the top of it came within a safe distance from the
water. As the load is increased, the hull sinks deeper and deeper. The
capacity of big boats is reckoned in tons. If a boat had a carrying
capacity of ten tons it would sink to what is called its "load
water-line" (L.W.L.) when carrying ten tons. As a load or cargo is
removed 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 the
water-line, water will leak in and in time completely fill the inside of
the hull, causing the boat to sink. Also, if too great a load or cargo
were placed in a boat, it would sink. It must be understood that water
leaking into a boat increases its load, and if it is not stopped it will
cause 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 a
one-foot ruler is made to balance (as shown in Fig. 3) at the six-inch
mark, the point at which it balances will be very close to the center of
gravity. The real center, however, will be in the middle of the wood of
which the rule is composed. It should constantly be kept in mind that
this "center of gravity" is a purely imaginary point.

Look at Fig. 4. If wires are arranged in a wooden frame, as shown, the
point where the wires cross will be the center of gravity if the square
formed by the wooden strips is solid. Every body, no matter what its
shape, has a center of gravity. The center of gravity is really an
imaginary point in a body, at the center of its mass. Oftentimes
engineers are heard saying that the center of gravity of a certain
object is too high or too low. Fig. 5 shows the center of gravity in a
boat. If the center of gravity in a boat is too high (as illustrated in
Fig. 6) the boat is said to be topheavy and unsafe. When a boat is
topheavy or its center of gravity is too high, the boat is liable to
capsize. In fact, some very serious marine accidents have been caused by
this 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 low
as possible. A boat with a low center of gravity will be very stable in
the water and difficult to capsize. This is true of model boats just as
much as it is true of large boats. The model boat builder must keep the
weight of his boat as near the bottom as possible. For instance, if a
heavy cabin were built on a frail little hull, the boat would be very
unstable and would probably capsize easily.




CHAPTER II

THE HULL


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

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

[Illustration: FIG. 7]

[Illustration: FIG. 8]


The construction of hulls on the built-up principle will be described
first. For the sake of convenience, the drawings of the boat-hull shown
in Figs. 7 and 8 will be followed out. Before going further it will be
well to understand drawings of boat-hulls; that is, how to know the
lines of a boat from a drawing. By the "lines" is meant its shape.
Marine architects employ a regular method in drawing boat-hulls. Fig. 7
shows the side of a boat and half of the deck plan. It will be seen
that 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, the
builder would have to use his own judgment as to the outline of the hull
at different places. For convenience, the boat is divided into ten
sections, represented by the lines 0 to 10. It will be seen that the
shape of the hull at section 2 will be different from the shape of the
hull at section 8. Again, section 0 will be much narrower than section
5.

[Illustration: FIG. 9]

Now look at Fig. 8. Note the shape of the cross-section of the hull at
the different sections. For instance, the line at section 1 in Fig. 8
represents the shape of the hull at section 1 in Fig. 7. It must be
remembered, however, that this is only half of the section, and that the
line 1 in Fig. 8 would have to be duplicated by another line to show the
true 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 the
hull, and the other half represents the stern half of the hull. If the
shape of the boat at section 10 is desired, the line 10 in Fig. 8 could
be traced on a piece of tissue paper. The paper could then be folded in
half and the line first made traced on the second half. This would then
produce the section of the boat at point 10. Thus, by closely examining
Fig. 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 the
various sections, it would appear as shown in Fig. 10 when assembled.

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

Motor-boating and marine magazines often publish the lines of different
boats, and if the young boat-builder understands how to read boat
drawings he will be able to make a model of any boat that is so
described.

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

First, it will be necessary to procure the lumber. Several clean white
pine boards will be very suitable to work with, and will not require
much skill in handling. Let us assume that the boat-hull is to measure
22 inches in length, with a depth of 4 inches. The beam, which is the
width of the boat at its widest point, will be 5 inches. (It will be
well to remember what the term "beam" means, since the term will be
used constantly throughout the book.)

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

[Illustration: FIG. 11]

After the boards are cut out mark them as shown in Fig. 11. The space
marked out on the board must be sawed out in two of the boards, to form
the inside of the hull, if the boat is to carry some form of power, such
as 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 of
the keyhole saw in one of these holes to start it and cut out the
piece. Treat the second board in the same way. The third board must
have a smaller portion cut out of the center, owing to the fact that
this board is nearer the bottom of the hull, where the width of the boat
is narrower. The width of the piece cut out in the third board should
not be more than 2 inches.

[Illustration: FIG. 12]

When this work is done, a very thin layer of glue is placed over the
boards, and they are then laid one on top of another. The boards are
then 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 much
on the boards. Too much glue is worse than not enough. It should be
merely a thin film.

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

[Illustration: FIG. 13]

At this point the hull sections from 0 to 10 must be marked off. By
referring again to Fig. 7 it will be seen that the sections 0 to 1 and 9
to 10 are not so far apart as the other sections. Section 0 is 1 inch
from 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 1
inch from 10 and 10 is 1 inch from the stern. Lines should be drawn
across the deck to correspond with these sections, which can be measured
off with a ruler. It will now be necessary to cut some templates, or
forms, from cardboard to guide the builder in bringing the hull to
shape. It will be an easy matter to make these templates by following
Fig. 8. A template of section 9 is shown in Fig. 14. It will be necessary
to make eleven templates, corresponding to the sections 0 to 10. The
templates should be cut from heavy cardboard so they will hold their
shapes.

[Illustration: FIG. 14]

The hull of the boat is now placed in a vise and roughly brought to
shape with a draw-knife. After it has been brought to shape by this
means a spoke-shave is used. This little tool has an adjustable blade by
means of which it is possible to regulate the cut. When the builder
starts to use the spoke-shave he should also start to use his templates
or forms, applying them sectionally to determine how much more wood he
will have to remove to bring the hull to shape. For instance, when he is
working in the vicinity of sections 5, 6, and 7 he will apply these
forms at the proper points occasionally to determine when enough wood
has been removed. This procedure is followed out the entire length of
the boat, care being taken to see that both sides are the same and that
too 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 to
finish the work need not make this mistake.

Of course, it will not be possible to bring the hull to a perfect finish
with a spoke-shave. This can be done, however, by the use of a coarse
file and sandpaper. The coarse file is used to take the rough marks of
the spoke-shave away, and the marks left by the file are in turn removed
by the sandpaper. The sandpaper must be applied unsparingly and always
with 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 be
understood that this method involves more work than the one just
described. Of course, the procedure of bringing the hull to shape by the
aid of the draw-knife, spoke-shave, and templates is the same, but the
hollowing out of the inside of the hull will be a much more difficult
job. However, with a couple of good sharp chisels and a gouge the work
will not be so difficult as at first appears. The use of an auger and
bit will greatly aid in the work. After the outside of the hull is
brought 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 major
portion of the wood has been taken out with the chisel, the gouge is
brought into use. The gouge should be used very carefully, since it will
easily go through the entire hull if it is not handled properly. For the
beginner 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 the
hull, 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 not
affected by moisture and it is therefore not so liable to warp and lose
its 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 is
known as the Sharpie type. A Sharpie hull is shown in Fig. 16. The
method of producing a hull of this type will be seen quite clearly by
reference to Fig. 17, which shows the boards and parts cut out ready to
assemble. The boards are made from 1/8-inch mahogany, which can be
obtained at any lumber-yard. First, the bow piece is cut to shape and
carefully finished. Then the two side pieces are fastened to it, as
shown in Fig. 18. The screws used should be brass, since iron screws
will rust and cause trouble. Three screws should be used for each side
board, and they should be driven into the bow piece so that the screws
on one side will not interfere with those on the other. The first
cross-piece is then screwed in place, as shown in Fig. 19. The second
and third cross-pieces are then screwed in place and the back or stern
piece attached. The bottom of the boat is then carefully put in place
with small screws. It will be noticed that the bottom board of the boat
is cut to fit the inside of the bottom. It is held in place with small
brass brads. The crevices or seams along the bottom of the boat should
be carefully covered with pitch or marine glue to prevent leakage when
the boat is in the water. The bow of the boat should be finished off
nicely to a point with a heavy file or a wood-rasp.

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

The young model boat builder is advised not to try to construct hulls
from metal. This is a very difficult task even for the thoroughly
experienced mechanic. Wood is much easier to work with and will produce
the 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 of
boats. The boats described will be constructed largely with blocks of
wood cut into various shapes and sizes. The results obtainable by this
method of construction are surprising, and there are few types of boats
that cannot be modeled by following the method. After the model-builder
has constructed a few boats along this principle he will be able to
duplicate the general appearance of almost any craft he sees by
carefully planning and cutting the blocks he uses.

The first boat described is a submarine. This is shown in Fig. 20. Four
blocks of wood form the basis of its construction, and these are cut
from 1-inch stock, as shown in the drawing. Such a submarine can be
made practically any size up to 12 inches in length. Beyond this size
they begin to look out of proportion and they are more difficult to
propel. After nailing the blocks together as shown in the drawing, a
small piece of sheet brass is bent at right angles and tacked to the
stern 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 are
placed. The opposite end of the rubber bands are fastened to a screw-eye
driven into the under side of the bow. A heavy piece of copper wire is
fastened to the stern of the boat by staples, and bent as shown. A
rudder is then cut from thin sheet brass, and the end of it is bent
around a piece of wire larger in diameter than the wire used for the
rudder-post. It is then taken from this wire and slipped over the wire
on the boat. It should be pinched in place by a pair of pliers, so that
it will stay in any position in which it is put. The end of the wire is
bent over so that the rudder will not slip off. The boat can be steered
in a circle or it can be made to go straight, depending upon the
position of the propeller.

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

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

The power plant of this boat is made up of rubber bands. The power
transmission to the propeller is a little different than the one
previously described. A gear and a pinion are salvaged from the works of
an old alarm-clock, and mounted on a piece of brass, as shown. A little
soldering will be necessary here to make a good job. By using the gear
meshing with the pinion a considerable increase in the speed of the
propeller is obtained, and therefore the speed of the boat is
considerably increased. The method of holding the power plant to the
bottom of the boat is made very clear. In order to bring the boat down
to the proper level in the water, a strip of sheet lead can be tacked to
the bottom. The builder should take care to get a piece of lead just the
correct weight to leave the surface of the deck awash. A coat of gray
paint 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 types
made without power plants. Many interesting little crafts can be
produced in this way, and the energetic model-builder can produce a
whole model harbor or dock-yard by constructing a number of boats of
different types according to the following instructions.

The first boat described will be the tug _Mary Ann_ shown in Fig. 22 and
Fig. 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 out
to the same shape with a keyhole saw and glued together. After the glue
is dry the blocks are placed in a vise and the top one or deck block is
planed down as shown. It will be seen that the deck inclines slightly
toward the stern of the boat. When this is done the hull is turned
upside down and the bottom of the stern planed off as illustrated. The
outside of the hull can be finished up with a sharp knife and a
jack-plane.

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

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

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

If tugs are constructed according to the design outlined above, the
model boat builder will also desire to have something that the tug can
haul. A very simple barge for this purpose is outlined in Figs. 25 and
26. This is formed of a single slab with the ends cut at an angle as
illustrated. A square flat piece is then tacked to the upper deck, which
acts as a cover. Four posts are then put in place in the same way as
those on the tug. One is placed in each corner. A boat or a scow like
this is generally painted red, and the model described can be made to
look 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 make
three or four of them at a time. If the pieces for several are cut out
at the same time, the construction will be just that much easier. If the
boat does not sink far enough into the water, a piece of lead should be
placed on the bottom to bring it down. This piece of lead should be
placed as near the center as it is possible to get it. Otherwise the
boat will list or tip at one end or the other. With a little patience
and care the weight can be so adjusted on the bottom as to bring the
scow to a perfectly level position. The reader will understand that the
water-line of a scow or any boat made according to the directions in
this book will depend largely upon the nature of the wood. In the first
Chapter of the book it was pointed out that the specific gravity of
different woods varies, and therefore the buoyancy will vary.

A model freighter is shown in Fig. 27. The hull of this boat can be
formed by two 1-1/2-inch planks. These will require a little hard work
to cut out; but, on the other hand, the effort will be entirely
justified by the pleasing appearance of the little craft that can be
produced in this way. A bow and stern block to raise the deck are cut
out and nailed in place, as shown. A cabin is also placed on the stern
of the craft, and this is formed by a block with a piece of cigar-box
wood placed on the top. The cigar-box wood should project a little over
the edges to form a canopy. The center of the deck can be raised by a
third block; and three independent blocks, two large ones and a small
one, form the main cabin. Sandwiched in between these blocks are three
pieces of cigar-box wood. The remaining details of the craft are so
simple 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 destroyer
is clearly illustrated in Figs. 28 and 29. This is very simple to
construct and makes a pleasing craft when finished. The hull is formed
by two blocks. One of these forms the raised deck on the bow of the
boat. The cabin is built up on this raised deck. It will be seen that
the part of the hull that rests in the water is formed by one block. In
building boats of this nature the constructor should be careful to keep
them long and slender, since torpedo-boat destroyers are always of this
type. They are high-speed craft, and their displacement must therefore
be as small as possible. Some of these boats carry four stacks and some
two. The author prefers four stacks as giving the boat a better
appearance than two. The two little cabins near the stern of the boat
are placed there merely to take away the plainness of construction. The
guns mounted forward and aft are merely round pieces of wood with a
piece 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 great
amount of pleasure, since he can add to his fleet from time to time and
have official launchings. Each boat can also be given a name and a
number. A little gray paint on the hull of these boats and black on the
stacks 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 twice
as long as a torpedo-boat destroyer. A view of the battleship as it will
look in the water is shown in Fig. 31. By carefully examining this
drawing the builder will be able to see just the number and shape of
the blocks that enter into the construction of the craft. The battleship
is provided with four main batteries mounted in turrets, one forward and
three aft. A mast is also built, and strings run from it to the top of
the main cabin and to the end of one of the turrets mounted aft. A screw
is placed through the centers of the fore and aft turrets, so they can
be turned to any position. Battleships should be painted gray. It will
be necessary to place rather a heavy keel on the boat just described in
order to bring it down to the proper depth in the water. Otherwise it
will be topheavy and will capsize very easily. A fleet of battleships
and battle-cruisers can easily be made according to the foregoing
instructions, and the builder should not be satisfied with producing
only one.

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

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




CHAPTER IV

STEAM AND ELECTRIC PROPULSION


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

The paddle-wheel really acts as a continuous oar. Such a wheel is shown
in Fig. 33. As the wheel goes around the paddle dips into the water and
pushes 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 a
paddle-wheel causes a boat to move. When a man gets into a rowboat, he
generally pushes himself off by placing his oar against the dock or
shore 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 a
man places his oar against the bank and pushes it, the bank does not
move, 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--part
is used in moving the water.

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

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

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

If a propeller acts in the same way as a screw, then it too must have a
pitch. The pitch, or the distance that a propeller will advance in one
revolution, is measured in inches. A propeller with a pitch of ten
inches should move ten inches through the water at each revolution.
However, there is a certain amount of "slip," and a propeller does not
actually advance the distance that it should theoretically. The pitch of
a propeller is really the distance it would advance in one revolution
if it were revolving in an unyielding or solid substance.

To make a simple propeller, first cut out of thin sheet brass three
blades as shown at _A_, Fig. 37. Sheet brass with a thickness of 1/32
inch 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 into
the depression. The same block is used for the three blades, so that
each 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 is
done.

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 a
piece of round brass stock. A hole runs lengthwise in the brass, as
shown, 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. The
hub is clamped between two boards placed in the vise, and a hacksaw is
used to cut a slot in the hub. The hub is then turned around one third
of a revolution, and another slot cut, using the same saw-marks in the
boards, so that the angle of the second slot will be the same as the
first one. The third slot is cut in the same manner. The three blades
that were cut out are now fastened in these slots and held there by
solder. This completes the propeller and it is now ready to be fastened
upon the propeller-shaft.

Let us consider the general method of putting the propeller-shaft in
place. The young boat-builder will readily understand that it would be
very impractical merely to bore a hole in the hull of the boat to put
the propeller-shaft through. In this way water would surely leak into
the hull and the boat would sink in a short time. Some method must be
evolved to keep the water out of the hull, and yet allow the
propeller-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 the
propeller-shaft. A little brass bushing must also be arranged at each
end, as shown. When the propeller-shaft is mounted in place in the
tube, there will be a space between it and the tube. Before the
propeller-shaft is put in place it is well smeared with vaseline, and
when it is placed in the tube the space between the shaft and the tube
will be completely filled with it. This will prevent water from
entering. Owing to the fact that vaseline is a soft, greasy substance,
it will not prevent the rotation of the propeller-shaft. The brass tube
is placed through a hole bored in the hull of the boat. The hole should
be a trifle smaller than the diameter of the brass tube, so that the
tube 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 rubber
bands. Such a boat is shown in Fig. 39. This is a small wooden hull
fitted with a two-blade propeller. The propeller is shown at Fig. 40. It
is cut in a single piece and held to the propeller-shaft merely by a
drop of solder since there will not be much strain upon it owing to the
low power of the rubber-band motor. The opposite end of the
propeller-shaft is bent into a hook, and the rubber bands run from this
to another hook placed at the bow of the boat. The rubber bands may be
similar to those employed by model airplane builders. The motor, of
course, must be wound up by turning the propeller around until the bands
become twisted into little knots, as shown at Fig. 39. Boats driven by
rubber bands cannot be very large unless a great number of rubber bands
are used. Even then the power is short-lived. However, building a few
small boats driven by rubber-band motors will do much to teach the
young boat-builder some valuable lessons in boat construction.

Probably the best method of propelling model boats is the electric
method. By building a boat large enough to accommodate two dry batteries
or a small storage battery and a little power motor, a very reliable
method of propulsion is made possible. The boat must have sufficient
displacement to accommodate the weight of the dry-cells and storage
battery. A boat two feet long, with a beam of 4-1/2 inches, is large
enough to accommodate one dry-cell and a small motor, providing the
fittings of the boat are not too heavy.

A suitable power motor for small boats, which will run with either one
or two dry-cells, is shown in Fig. 41. The connections for the motor are
given clearly in Fig. 42, and a suitable switch to control the motor is
shown 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 are
also costly, since they do not last long and cannot be worked too hard
unless 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 in
Figs. 44 and 45. It will be noticed that the motor is inverted. A small
pinion or gear is mounted upon the armature-shaft of the motor. A larger
gear (about three times the diameter of the small one) is placed upon
the propeller-shaft. This gives a speed reduction of three to one. It
will be seen that the propeller-tube is strapped within a strip of brass
to a small cross-piece nailed to the bottom board of the hull. The hull
is of the built-up type, and the other three boards that go to make it
up are not shown. When the three boards are glued in place, a brass
strip is run across the top board and the base of the motor is screwed
to this. This holds the motor rigidly in place so that it will not move
when the power is turned on. The brass strip used should have sufficient
thickness to hold the motor rigid. It will also be seen that the motor
is tipped slightly so that it will come in line with the
propeller-shaft.

[Illustration: FIG. 46]

[Illustration: FIG. 47]

[Illustration: FIG. 48]

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

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

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

[Illustration: FIG. 49]

[Illustration: FIG. 50]

[Illustration: FIG. 51]

Here is a very simple small power plant suitable for driving boats up to
3-1/2 feet in length. The boiler is shown in Figs. 49 and 50. The method
of assembling the boiler is pictured clearly in Fig. 49. A brass or
copper tube about 2-1/2 inches in diameter is used. Two end pieces are
cut to shape and forced into the boiler ends. A hole is drilled in the
center of these pieces before they are put in place. After the end
pieces are forced in place solder is carefully flowed around their
edges. The brass rod is then threaded at each end and placed
concentrically within the boiler, as shown in Fig. 49. A nut is placed
on each end of this rod and tightened. The nut is then soldered in
place. This brass rod, called a stay-rod, prevents the end of the boiler
from blowing out when the steam pressure has reached its maximum value.
Three holes are drilled in the brass tube, as shown. One is to
accommodate the steam feed-pipe that goes to the engine; another is for
the safety-valve, and still another for the filling plug. The
safety-valve and filling plug are both shown in Fig. 51. The little
spring on the safety-valve is adjustable, so that the valve can be
regulated in order to prevent it from blowing off at pressures lower
than that at which the engine operates.

[Illustration: FIG. 52]

A suitable firebox for the boiler is shown clearly in Fig. 52. This is
cut to shape from stovepipe iron and held together with small rivets.
Holes should be punched or drilled in the side of the firebox to give
the burner a sufficient supply of air. The burner is illustrated
clearly in Fig. 52. The fuel-tank can be made from an ordinary tin can
with the cover soldered on, and a hole made for a cork by means of which
it is filled with denatured alcohol. A little pipe runs from the
fuel-tank to the burner. It is advisable, if possible, to place a small
valve in this pipe to cut off the fuel supply when necessary. The only
other 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 as
illustrated. 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 the
wool by capillary attraction, where it burns with a steady hot flame at
the surface of the copper gauze. In the corner of the can near the
feed-pipe another small piece of copper gauze is soldered as shown. This
covers up the feed-pipe entrance so that the asbestos will not plug up
the pipe.

[Illustration: FIG. 53]

[Illustration: FIG. 54]

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

[Illustration: FIG. 55]

The cylinder of the engine should be made first. This is made from a
piece of brass tubing with an internal diameter of 3/4 inch. Two end
pieces, or a cylinder-end cover and cylinder head, must be cut to fit
inside 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 to
accommodate the piston-rod. The cylinder head is then soldered in place.
The cylinder-end cover should be left until the piston-rod and piston
are 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 small
square piece of brass is placed on the opposite end of the piston-rod to
act as a bearing. This little piece is cut and drilled as shown in the
drawing. Before it is soldered in place on the piston-rod the
cylinder-end cover should be placed on the rod. Both the piston and the
cylinder-end cover can then be placed inside the cylinder, and the
piston-end cover is soldered in place. Before final assembling the
piston should be made to fit nicely into the cylinder. This can be
brought about by applying emery cloth to the piston-head until it slips
nicely into the cylinder with little or no play. Thus a steam-tight fit
is made, and this contributes greatly to the efficiency and power of the
engine.

[Illustration: FIG. 56]

[Illustration: FIG. 57]

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

The second cylinder block is now finished according to the drawing. This
has two holes 1/8 inch in diameter bored in it. One of these holes is
the steam inlet and the other the exhaust. When the cylinder is at one
side of its stroke the hole that was bored in the top of the steam block
which was soldered on the cylinder is in line with the inlet hole in the
block under consideration. Steam then enters the cylinder and forces the
piston down. This turns the crank around, and the crank in turn pulls
the piston over to the opposite side, so that the hole in the first
piston block of the cylinder now comes in line with the exhaust hole on
the second cylinder block. The steam in the cylinder escapes and the
same operation is repeated over again. Of course, it must be understood
that this steam admission and exhaust takes place very rapidly. The hole
in the second cylinder block, which goes over the pivot, must be made a
trifle more than 1/8 inch in diameter, so that it will slide freely over
the pivot.

The engine is mounted on a very simple frame, which is a piece of
1/16-inch brass cut and bent as illustrated. After it is cut and bent to
shape the second cylinder block is soldered in place. The cylinder can
then be mounted. It will be seen that the pivot goes through both the
second cylinder block and the engine standard. A small spring is placed
over the protruding end of the pivot and a nut put in place. By turning
this nut the pressure on the face of the two cylinder blocks can be
adjusted, and the model engineer must always remember that the pressure
on these springs must be greater than the steam pressure in the
feed-pipe. Otherwise the steam pressure will force the cylinder-block
faces apart and steam leakage will result. On the other hand, the
pressure of the spring should not be too great, since that would
interfere with the free movement of the engine cylinder.

Nothing now remains to be made except the crank and the flywheel. The
crank revolves in a small brass bearing which is soldered in place on
the engine standard. It will be seen that the sheet brass that makes up
the engine standard is not thick enough to offer a good bearing for the
crank. 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 while
the bending is done. This will prevent it from fracturing, and will also
permit a sharp bend to be made.

The flywheel is a circular piece of brass 1 inch in diameter. Its center
is 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 as
illustrated, and two small brass pins are cut out from 1/8-inch brass
rod and forced into these holes and then soldered. These provide a
method 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 of
small copper tubing. It may be necessary to mount the engine on a small
block, as shown in Fig. 53. After the steam in the boiler has reached a
sufficient pressure the engine crank should be given a couple of twists
in order to start it. Before operating the engine a little lubricating
oil should be run into the cylinder through the inlet or exhaust ports.
The cylinder should always be kept well lubricated. The contacting faces
of 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 and
cannot be made to run, take the burner from under the boiler so that
steam will cease to be generated. With the safety-valve the model boat
builder need have little fear of an explosion. Nevertheless the
foregoing directions should be carefully adhered to.




CHAPTER V

AN ELECTRIC LAUNCH


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

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

After the pieces that form the hull are cut they are thoroughly
sandpapered to produce a smooth surface. The heavy imperfections in the
wood can be taken out with coarse paper, and the finishing can be done
with a finer paper. It is understood that sandpapering should always be
done with the grain, never across the grain. The sides of the boat are
cut about 1/4 inch thick, but they are planed thinner in places where
the bend is most pronounced. The side pieces are 2-3/4 inches deep at
the stern and 2-1/4 inches at the stern. There is a gradual curve from
the 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-inch
wood. It is cut to the shape shown at Fig. 58, and beveled along the
bottom edge to enable it to be fixed on the slant. The bow piece is a
triangle 2-3/4 inches in length.

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

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

[Illustration: FIG. 58]

[Illustration: FIG. 59]

[Illustration: FIG. 63]

The stern tube is 3/8 inch, outside diameter. A hole is bored in the
bottom of the boat to receive the stern tube. This job must be done
cautiously; otherwise the bottom of the boat may be ruined. It is best
to screw a substantial block to the inside of the boat. This block
should 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 the
bottom to the stern should be about 12-1/2 inches. The stern tube should
be mounted as nearly parallel with the bottom as possible, since on this
depends the speed of the boat. As the angle of the propeller-shaft
increases, the speed of the boat will decrease. In drilling the hole the
boat-builder should be careful to keep the drill running along the
central line of the boat.

As before mentioned, the stern tube is a piece of brass tubing 3/8 inch
in diameter and 8 inches long. It is filed square at both ends, and a
brass plug is fastened with solder in each end. The tube is then filled
with melted vaseline, which is allowed to cool. The hole in the hull
around the tube is then well smeared with thick paint. When this is
done, a layer of red lead or putty is placed around the joint both on
the 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 way
down the boat. When the turtle-deck is finished, it is best to lay it
aside, before finally fastening it in place, until the entire boat is
completed.

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

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

The finished Sharpie hull without its driving batteries or motor should
weigh about 1 pound 3 ounces. The hull being finished, let us consider
the electric propelling equipment.

A 1/8-inch cold-rolled steel driving or propeller-shaft is used. The
shaft is 13 inches long and a gear-wheel 1 inch in diameter is fixed to
one end of this shaft. This gear-wheel meshes with a brass pinion on the
motor-shaft. This forms a 3-1/2 to 1 reduction gear, which produces a
greatly increased speed of the boat. The other end of the
propeller-shaft rests in the skeg bearing. In this present case this
consists of a tube about 1/2 inch long, which is made for a revolving
fit on the propeller-shaft and supported by a sheet-metal bracket. This
is shown in Fig. 63. The end of the propeller also revolves adjacent to
the 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 a
very simple type obtainable in the open market. It is similar to one
shown in Fig. 41. As before mentioned, either dry or storage batteries
may be used as a source of current. The writer strongly advises the use
of storage batteries if possible. The initial cost of these batteries is
greater than that for dry batteries; but, on the other hand, the small
storage battery can be charged repeatedly and will outlast many dry
batteries. If the boat is used much the storage battery will probably be
the more economical of the two.

The steering gear of the boat is very simple. The rudder works in a
bearing that is screwed to the stern piece. The end of the rudder-shaft
is tapped, and a brass screw is used to clamp it in position after
setting 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 is
placed 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 releases
her]

[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 makes
a very pleasing combination. Fig. 60 shows a rough plan of the general
arrangement of the power machinery. Figs. 61, 62 and 63 will do much to
give the reader a clear idea of the method of construction which could
not be gained by reading a description.

[Illustration: FIG. 61]

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

[Illustration: FIG. 62]

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




CHAPTER VI

A STEAM LAUNCH


THE steam launch _Nancy Lee_ is an attractive little craft when finished
and it is capable of attaining considerable speed. It is really designed
after the cruising type of motor-boats. This type of boat is
particularly adaptable for simple model-making, owing to the elimination
of awkward fittings. The power machinery is of very simple construction
and 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. The
hull, when planed on all sides, should be 30 inches long, 6-1/2 inches
wide, and 3-3/4 inches deep. A center line is drawn down the length of
the hull, and five cross-section lines are drawn at right angles to the
center line 5 inches apart. On these lines the builder should mark off
the greatest lengths of the boat, taking the dimensions from the
half-breadth drawing shown in Fig. 64. It will be noted that the deck is
wider than the L. W. L. forward and narrower than the L. W. L. at the
stern. The block should be cut to the widest line on the half-breadth
part.

[Illustration: FIG. 65]

[Illustration: FIG. 67]

[Illustration: FIG. 64]

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

[Illustration: FIG. 66]

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

[Illustration: FIG. 68]

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

[Illustration: FIG. 69]

The next job is to cut and properly fit the raised portion or
forecastle. A piece of wood 1-1/4 inches thick, 15 inches long, and
6-1/4 inches wide must be prepared and laid in place on the hull. The
shape of the hull is marked off with a pencil and the wood sawed along
this line. The inner portion is also cut out, thus making a V-shaped
piece 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. The
hull is neatly finished by cutting in the sheer or curvature of the hull
and sandpapering it all over. A cross-beam or support, _C_, Fig. 70, is
cut and fitted as illustrated. This particular piece supports the
fore-deck, and also carries the main-deck, as well as bracing the boat
together. 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 builder
should select clean pieces, free from knots and blemishes. It only
requires 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 be
cut in the deck. The coamings and seats are cut to the sizes indicated
in the drawings. They are then glued and pinned together. When fitted to
the 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 be
removable, two battens must be fitted to the under side to keep it in
place. The openings for the hatchways can be cut and the hatch-covers
made 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 the
hatch opening, is shown at Fig. 72. A coping-saw will be found very
useful for this work. The covers are neatly rounded on the edge and
nicely 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 the
boat at this stage. It will be seen that the sketch shows the deck
broken away so as to render the cross-batten visible, which also shows
the fair-lead at _F_, Fig. 73. This is cut from two small pieces of
3/16-inch stuff, glued and pinned in place. The forward deck is
completed by the addition of cowl-ventilators, cut from hard wood and
screwed in place. The flag-mast is made from a short piece of 1/16-inch
wire. The details of the mooring-cleats are shown in Fig. 74. They are
fashioned by using a small screw-eye and soldering a short piece of
brass wire through the eye. An oblong metal plate is then cut and a
central hole drilled. This plate is soldered to the shank of the
screw-eye and the cleat is complete. One of these devices is to be
fitted 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 the
stern of the boat with the rudder gear mounted in place. It will be
noted that the rudder-blade is merely a piece of sheet brass cut to
shape and soldered into the rudder-post _M_, which is slit to
accommodate it. The rudder-post is hung in two screw-eyes on the stern
of the boat. A small wheel about 1 inch in diameter, with an edge filed
in 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 two
screw-eyes on the deck. From this it is led through an opening in the
coaming to a drum on the steering column, which is turned by another
small wheel similar to that used on the rudder-post, but with a round
edge. The steering column is merely a piece of 1/8-inch wire, held in
place by two small screw-eyes fixed in the coaming and with a tube-brush
soldered on to keep the wire in position. The drum is simply a hard-wood
bushing 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 to
Fig. 77, which is a view of the complete boiler and engine mounted
together on the same base. The boiler is shown at _A_ and the
safety-valve and filler at _L_. The base or firebox _B_ protects the
burner from stray drafts of air, and also supports the boiler.

The lamp or burner consists of a receptacle _C_ for containing the
denatured alcohol. The denatured alcohol is inserted through the
filler-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 as
shown in _F_, and they give sufficient heat to produce steam enough to
drive the cylinder _G_. The steam is conducted to the cylinder through
the short pipe _K_. The steam-cylinder has the usual piston and rod,
which drives the circular crank _H_. This crank is mounted on a
crankshaft carried on the metal tube _M_. As will be noticed, the
cylinder is of the simple oscillating type mounted on a standard, formed
as part of the boiler casing, and stiffened by two angle-plates _L_.

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

The boiler is made from a strong tin can about 1-3/4 inches in diameter
and 4-1/2 inches long. It is cleaned inside and out, and all the seams
are double-soldered. The lid is also soldered on the can. This little
boiler, although not elaborately made, will be found capable of standing
up under considerable steam-pressure, and so no fear need be had of
accidents 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 boiler
are shown clearly in Fig. 78. A piece of sheet tin is cut out to the
size and shape illustrated in Fig. 79 at _A_. The piece is bent up at
the dotted lines and the seams are soldered. Two angle-plates, _B_, are
then cut and fitted and soldered in place. Next a piece of brass tube
with a 1/8-inch bore and 1 inch long is cut and soldered in place for
the bearing of the crankshaft. A lead flywheel 1-1/4 inches in diameter
and 1/2 inch thick is then mounted firmly on a piece of straight steel
wire 1-3/4 inches long, which acts as a shaft.

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

A little crank must be cut from 1/16-inch brass, and soldered to the
crankshaft after fitting a wire crank-pin to the outer edge. This
crank-pin should be of such a size that the joint on the end of the
piston-rod shown at _A_, Fig. 80, turns on it easily. The throw should
be 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, so
that they just support the boiler nicely. They are then soldered in
place. Next fit the short steam-pipe _K_ between the boiler and the
steam block on the cylinder. The builder should take care to keep the
steam-pipe well up to the top of the boiler.

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

Before operating the engine with steam, it can be tested with a small
bicycle pump through the opening for the safety-valve. The engine should
turn over briskly at every stroke of the pump, providing it does not
come 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 a
little twist and the engine will then start. Before steam is applied it
will be well to experiment until the engine runs with the air-pump.

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

The propeller-shaft is merely a piece of steel wire, perfectly straight
and fitted with a crank _A_, Fig. 82. This crank is similar to the one
fitted to the engine, but with a small slot cut out for the crank-pin to
fit into. This is done so that, as the crank-pin on the engine turns
around, 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 in
place on the stern of the boat the propeller-shaft will be in line with
the crankshaft of the engine.

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

The propeller must now be made. This is easily done by cutting out a
disk of brass 1-1/2 inches in diameter, as shown in Fig. 83. The shaded
portions 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, the
propeller is soldered to the propeller-shaft.

The only part of the job that remains is to screw the boiler in place
under the fore-deck of the boat. This done, the _Nancy Lee_ is ready for
her trial. The fore-deck should be made removable by fitting it with
pins or screws with the heads cut off, so that the deck only needs
pushing into place. This little boat should be capable of attaining a
speed of from four to five miles an hour if it is made carefully and
according 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 will
probably be familiar to many readers. It is a type of boat used on the
Great Lakes, and, owing to its peculiarity of design, it lends itself
very 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 the
beam at the water-line is 8 inches. The extreme draft will be in the
neighborhood of 5 inches. This model, when completed, will be capable of
carrying considerable weight; in fact, it is able to accommodate
thirty-five pounds in weight when used in fresh water. This will give
the builder an opportunity to install a very substantial power
equipment with little regard for weight.

[Illustration: FIG. 84]

[Illustration: FIG. 85]

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

The bottom plank is shaped with a knife to conform to the lines of the
boat. In building up the hull with the planks, they should first be
smeared with glue, and when put in place a few brass brads should be
driven in. As mentioned in an earlier part of this book, iron nails
should not be used in work of this nature, owing to the fact that they
will rust and cause trouble. The brass brads are placed about one inch
apart the entire length of the boards. The hull is finished with a plane
and sandpaper, and after it has been brought to shape in this way and
finished, a coat of paint is applied. Black with dark red trimmings
makes 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 are
added to the deck. Six of these hatches can be made by merely gluing a
square piece of 1/4-inch wood to the deck. The seventh hatch should be
made with a hole cut in the deck, so that access can be had to the power
motor.

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

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

The rudder is cut from a piece of sheet brass to the shape shown, and
fitted with a quadrant. The engine cabin can be made from cigar-box
wood. The windows and doors can either be painted in place, or the
windows can be cut and backed up with sheet celluloid. A good substitute
for painted doors will be found in small pieces of tin painted a
different color from the cabin. The same procedure may be followed in
fitting the windows and doors to the forward cabin.

We are now ready to consider the power plant. Owing to the large
displacement of the boat, it will carry a fairly heavy storage battery.
The electric motor and storage battery are mounted in the manner shown
in Fig. 85, which will also give the reader an idea of the appearance of
the finished model. As the drawing indicates, it will not be necessary
to tilt the motor to any great degree in order to bring the propeller to
the proper depth. This is because of the depth of the boat. Instead of a
string or belt to connect the motor with the propeller, the shaft of the
motor is taken out and replaced by a longer steel rod that will serve
both as a motor-shaft and a propeller-shaft. The propeller-shaft extends
from the motor through the stern-tube. The propeller used for this model
is a three-blade affair, 3 inches in diameter. It must be of this size
in 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 not
mounted directly in line with the stern-tube the propeller-shaft will
have a tendency to bind. However, with a little care no trouble should
be experienced from this source. The storage battery used should be of
the four-volt forty-ampere hour variety. This boat will be capable of
carrying such a battery and this weight should just bring the craft down
to her load water-line. The whole deck is made removable, so that the
storage battery can be taken in and out at times when it is necessary to
recharge it. A battery of this capacity, however, will drive a small
motor 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 the
text of this Chapter is a presentable little boat with pleasing lines
and deck fittings. There is nothing difficult about its construction,
and, considering the amount of work necessary to produce it, it is
probably one of the most pleasing boats described in the book. If made
correctly it will look "speedy" and shipshape.

The general outline of the boat can be gathered from Figs. 86, 87, and
88. Fig. 86 gives a side view of the craft; Fig. 87 shows the bow, while
Fig. 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 the
Sharpie type, but the lines are changed to give the boat a more graceful
appearance. This is done by changing the shape of the deck and the
bottom pieces. Fig. 89 shows the various pieces necessary to construct
the hull. It will be seen that the forward portion of the bottom piece
is narrower than the deck piece, and broadens out so that it is wider at
the stern than the deck piece. The deck piece has a maximum width of 5
inches, while the bottom piece has a width of 4 inches at the forward
section. The deck measures 3-1/2 inches at the stern, while the bottom
piece measures 4-1/2 inches at the stern. This produces a half-inch
taper on each side of the stern. A half-inch taper is also produced on
the 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 not
available, choose some other close-grained wood, free from knots and
blemishes. Paper patterns are made to correspond with the general shape
of the pieces that form the hull as given in Fig. 89. The pieces, after
being marked, are cut to shape with a keyhole-saw. After this is done
their edges should be trimmed neatly with a jack-plane.

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

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

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

[Illustration: FIG. 93]

[Illustration: FIG. 92]

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

The deck and deck fittings should now be furnished. The construction of
the forward cabin is shown in Fig. 93. The sides and back are formed
with cigar-box wood, while the curved front can best be made with a
piece of tin. The top is also cut to shape from cigar-box wood, and
should 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. Four
little lugs cut in the tin are bent on the inside and each provided with
a hole. These lugs are used to tack the pilot-house to the deck. A small
skylight is produced from a solid piece of wood and tacked in place as
illustrated in the drawing.

The builder is cautioned not to destroy the appearance of his boat by
making the mast too large. After the mast has been nicely sandpapered, a
little wire frame is bent to shape and fastened to the top, as shown in
Fig. 87. The little wire railing that is placed in front of the mast is
then bent to shape, and this and the mast are put in their permanent
position. The mast can be held to the deck by boring a hole a little
under size and smearing the bottom of the mast with a little glue before
it is forced in. Pieces of black thread are run from the top of the mast
to the railing at the bottom, as shown. These threads are used to hoist
signal 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 of
the deck and the position it occupies should be marked out with a
pencil. This portion of the deck should be carefully cut out with a
coping-saw. The cabin is then forced into the opening. The fit should be
fairly 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 made
accessible.

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

[Illustration: FIG. 94]

The cabin which is placed aft on the boat, is of very simple
construction. 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 the
deck of the boat. The mast should be only three-fourths as high as the
forward mast, and a tiny hole is drilled near the top. Into this hole a
small piece of soft wire is placed, and from this wire a thread runs to
the cabin. A small flag can then be placed on the thread, as illustrated
in Fig. 86.

Six port-holes are now bored in each side of the hull with a 1/2-inch
bit. These can be backed up with mica or celluloid. Five smaller
port-holes made with a 1/4-inch drill are then bored in each side of the
forward 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 thorough
rubbing with sandpaper. A battleship gray with maroon trimmings makes a
pleasing color combination for this boat.




CHAPTER IX

BOAT FITTINGS


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

Using a little care, it is possible to make presentable fittings by
utilizing odds and ends found about the household and shop. In this
Chapter the author will describe the construction of the more important
fittings 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 very
suitable method of producing a smokestack is shown in Fig. 95. The stack
itself is cut from a piece of thin brass tubing. It is also possible to
use 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. If
the stack is painted either gray or white a red band near the top of the
stack 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 very
clearly. First a block of wood is cut about the same diameter as the
internal diameter of the stack. This block of wood is then forced up
into the stack. A small square base is then cut, and fastened to the
block on the inside of the stack with a wood-screw. It might be
mentioned here that it is often necessary to drill a hole with a small
hand 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 held
to the deck of the boat by two small screws driven up from beneath. The
guy-wires can then be fastened on. The guy-wires should be made of very
fine wire, since heavy wire would be entirely out of proportion. The
wire can be fastened on the stack by drilling a tiny hole through the
stack. A knot is then tied in one end of the wire, and the opposite end
threaded through the hole. Small screw-eyes driven into the base piece
are used to anchor the guy-wires.

Ventilators are a very important part of the boat. The model-builder
will encounter considerable trouble if he attempts to make his
cowl-ventilator from metal, unless he is very experienced in drawing
copper out by hand. The writer has found a method of producing
cowl-ventilators by the use of clay pipes. Clay pipes can be purchased
for a few cents each, and when cut down as shown in Fig. 96 they form
very suitable ventilators. The pipe can be cut as shown by the use of a
file. The ventilator is held to the deck of the boat by being forced
into a hole in the deck that is just a trifle under size. Of course, the
forcing will have to be done carefully to prevent the stem from
cracking. The inside of the ventilator should always be painted red, and
the outside should be the same color as the boat. Ventilators made in
this way absolutely defy detection and do much toward bettering the
general 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 shown
in Fig. 97. This is an electric light, and the batteries used to propel
the boat can be used for the light. First a small circular piece of wood
is cut out, as shown at _A_, Fig. 97. The center of this is drilled out
to accommodate a small flashlight bulb. A tiny brass screw is then
driven into the piece of wood, so that it will come in contact with the
center of the base of the flashlight bulb. This little screw forms one
of the electrical contacts, and one of the wires from the battery is
attached to it.

A little strip of brass is then cut as shown in _B_, Fig. 97, and
provided 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 a
little larger in diameter than the outside of the wooden piece in which
the flashlight bulb is mounted. This little piece is then fastened to a
wooden post with a small brass pin, as shown in Fig. 97. Two more pins
are used to hold the wooden piece to the searchlight proper. One of
these pins is driven through the wooden piece until it comes in contact
with the base of the flashlight bulb. This forms the other electrical
connection, and the second feed wire from the battery can be attached to
the little brass piece that holds the searchlight. Both the feed wires
from the battery can come up through a hole in the deck close to the
wooden post upon which the searchlight is mounted.

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

[Illustration: A POWERFUL GASOLENE BLOW-TORCH

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

A word will be said here about finishing the deck of a model boat. It is
a 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, of
the average young model-builder. A very simple method of producing
imitation planking is shown in Fig. 99. A sharp knife and a
straight-edge are the only tools for this work. The straight-edge is
merely 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 is
finished in this manner and varnished over, a very pleasing effect is
produced. In fact, if the work is done carefully, the deck looks very
much 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 Central
Park, New York City. The author presented the cup to the owner of Elmara
III, the winning boat, which attained a speed of nearly thirty miles an
hour]

[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 to
shape 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 the
davits. The davits are shown in Fig. 101, at _A_ and _B_. They are made
by bending a piece of small brass rod, as shown. One end of the rod is
hammered flat, and a hole is made in it with a very small drill. Holes
a little under size are drilled in the deck, and the davits are forced
into these. The method of suspending the life-boat from the davits is
shown at _B_, Fig. 101. The little blocks of wood are glued on to a
thread to represent pulleys, and they are, of course, only imitation or
dummy pulleys.

[Illustration: FIG. 102]

The method of producing port-holes is shown in Fig. 102. A hole is first
bored through the wood with a bit of the proper size. The size of the
port-holes depends entirely upon the size of the boat. A piece of brass
tubing is then cut off with a hacksaw to form a brass bushing. The
outside diameter of this tubing should be the same as the size of the
bit used. For instance, if a 1/2-inch bit is used, brass tubing 1/2 inch
in diameter should be purchased. Such tubing can be obtained from any
hardware store. Celluloid, such as that used for windows in automobile
curtains, is glued to the inside of the port-holes. This makes a
splendid substitute for glass. It can be obtained at garages and
automobile supply stores for a few cents a square foot. The model boat
builder can also use either mica or glass for this purpose, although
thick glass looks somewhat out of place.

A binnacle is shown in Fig. 103. This is made from a solid piece of wood
cut with a semi-spherical top. The steering-wheel is made of a wheel
from 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. A
pin driven through the center of the steering-wheel is used to fasten it
to the binnacle. The binnacle itself can be held to the deck either by
glue or by a small screw.

[Illustration: FIG. 103]

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

A wireless antenna is shown at Fig. 105. This is a fitting that will do
much toward improving the appearance of any craft. Very fine copper wire
is 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 is
placed. Black beads slipped on the wire serve very well as insulators.
The lead-in wire which drops to the wireless cabin is attached to the
aërial by winding it around each one of the aërial waves. The aërial
should be suspended between the masts of the vessel. A few words should
be said about masts in general. If there is one way in which a
model-builder can destroy the appearance of a model boat, it is by using
badly proportioned masts. The average boy seems inclined to use a mast
of too great a diameter, which makes it out of proportion with the rest
of the boat. It is better to have a mast too small rather than too
large.

The method of producing railing is shown in Fig. 106. The same small
brass rod that was used for the davits can be used for the rail
stanchions. One end of the stanchions is hammered flat and drilled out.
The stanchions are fastened to the deck by first drilling small holes
and forcing them into it. Thread or very fine wire is used for the
railing. Fine wire is preferred owing to the fact that it will not break
so 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 remembered
that stairs are often used in model-boat construction. First a strip of
tin 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, are
soldered to the side pieces, as shown. The railing can be made from
copper wire or black thread.

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

A small quick-firing deck-gun is shown in Fig. 109. This is a very
simple fitting and can be made with very little difficulty. The base of
the gun is formed by cutting a thread-spool in half. A piece of small
brass tubing is used to form the barrel. A little piece of sheet tin is
looped over the back of the gun to represent the breech. A tiny piece of
wire is held to the side of the breech with a drop of solder, to
represent 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 that
passes through the barrel of the gun will also pass through this hole
and into the spool. The center of the spool should be plugged to hold
the nail. After the gun is painted gray or black it will appear very
businesslike, considering the small amount of labor spent in producing
it.

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

A common hatch is shown at Fig. 111. This can be made in the form of an
open box from cigar-box wood, and glued to the deck. It is not necessary
to 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. This
is a very simple piece of work and will need little description. Several
stay-wires should be fastened to the main-mast and held to the deck with
small screw-eyes. The boom should be made a trifle smaller in diameter
than the mast. The pulleys are dummy, like those on the life-boat. A
little hook bent to shape from copper wire is placed on the end of the
thread, as shown.

[Illustration: FIG. 112]

[Illustration: FIG. 114]

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

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

A rudder is shown in Fig. 115. The rudder-post should be a piece of
brass rod so thick that it can be split with a hacksaw. The sheet brass
that forms the rudder proper is placed in this split and soldered. In
the 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 in
adjustment in this way.

If the rudder is to be kept in a certain adjustment a quadrant is
necessary. This is made by using a semicircular piece of heavy sheet
brass and filing little notches in it. The lever of the rudder rests in
these notches, and by this means the rudder can be held in any one
position, 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 of
different design, the author thinks it advisable to put the reader in
possession of the fundamentals of model steam-engine design and
construction. In this way the model engineer will be able to design and
construct model steam-engines according to his own ideas and in
accordance with the raw materials and miscellaneous parts he may find in
his workshop. Unless the young mechanic is in possession of a very well
equipped workshop, it is quite impossible to construct a steam-engine
according to certain specifications. However, if he has in mind the
fundamental principles of steam-engine design, he can go ahead and
design his engine, for which he will have no trouble in machining or
producing the parts that enter into its construction. By this the
author means that the workman can design his engine to meet the
materials he has on hand.

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

[Illustration: FIG. 117]

Having learned how motion is imparted to the piston by the expansion of
steam under pressure, attention is directed to what is known as the "D"
slide-valve. This slide-valve permits steam to enter the cylinder and to
exhaust at proper intervals. See Fig. 118. Steam enters the steam-chest
through the pipe _A_. The slide-valve is shown at _D_. When the
slide-valve is in the position shown, steam enters the cylinder, and by
the time the cylinder has arrived in the position shown by the dotted
line _C_, the slide-valve moves over, closing the passage _B_. The steam
under pressure forces the piston to the opposite end of the cylinder.
When the piston reaches the opposite end of the cylinder, steam that has
entered through the passage _F_ again forces the piston back to its
original position. This is caused by the slide-valve shifting its
position, because of the impulse it received at the opposite end of the
cylinder. Thus it will be seen that when the piston is at one end of the
cylinder the opposite end is exhausting. By carefully studying Fig. 118
the 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 to
revolve.

[Illustration: FIG. 118]

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

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

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

[Illustration: FIG. 119]

Your attention is directed to Fig. 119. This shows a design for a model
single-cylinder, single-acting steam-engine. The reader should carefully
study each drawing before continuing to digest the following matter. The
cylinder _L_ can be made from a piece of tubing. This can be either
brass or copper. Aluminum should not be used, owing to the fact that it
is difficult to solder and difficult to work with. The piston is made so
that it will fit nicely into the cylinder and move up and down without
binding. It will be seen that a groove, _M_, is cut around the piston
near the top. String soaked in oil is placed in this groove. This is
called packing, and the presence of this packing prevents steam leakage
between the piston and the cylinder walls and thereby materially
increases the efficiency of the engine.

In this case the connecting-rod _R_ is made in a circular piece. It is
attached to the piston by a pin, _F_. The connecting-rod must be free to
revolve 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 of
7/8 or 7/16 inch from the center of the disk _N_, so that when this disk
makes one revolution, the piston will move 7/8 inch in the cycle. Thus
it will be seen that the distance of the crank-pin _K_ from the center
of the crank disk _N_ will depend entirely upon the stroke of the
engine. It may be well to mention here that the worker should always
start designing his engine by first determining the bore and stroke.
Everything depends upon these two factors. It is also well to mention
here that the piston should never travel completely to the top of the
cylinder--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 engine
shown bear no resemblance to the _D_ valve previously described. The
holes _G_ which are bored around the cylinder are the exhaust ports. It
will be seen that when the piston is at the end of its downward stroke
it uncovers these exhaust ports and permits the steam to escape. The
momentum of the flywheel _A_ pushes the piston upward, closing these
holes. 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 the
piston has reached the upward limit of its stroke a considerable steam
pressure has developed on top of the cylinder, and this again forces the
piston downward. Thus the same cycle of movement is gone through
repeatedly.

The valve on this little engine is extremely simple. It consists of a
circular piece of brass drilled out, as shown. A hole (_I_ and _J_) is
drilled transversely through this. The little cylinder shown in the
insert at _O_ slides in the larger hole, and when it is at its upper
limit it cuts off the steam. At the proper intervals the valve is pulled
down 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 close
and open at proper intervals. When the engine is made, the eccentric can
be shifted about by means of a set-screw, _Q_, until the engine operates
satisfactorily. This set-screw is used to hold the eccentric to the
crank-shaft. The word eccentric merely means "off center." Thus the
eccentric in this case is formed by a little disk of brass with the hole
drilled off center. The distances these holes are placed off center will
depend entirely upon the motion of the valve. It will be seen that the
valve is connected to the eccentric by means of the valve-rod _E_. The
valve-rod, in turn, is held to a circular strap which is placed around
the 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 too
tightly and the eccentric is free to revolve within it, the valve will
be forced up and down as the eccentric revolves.

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

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




CHAPTER XI

A MODEL FLOATING DRY-DOCK


AS many of the readers probably know, a dry-dock is used in assisting
disabled vessels. Some dry-docks are permanent, while others are built
so that they can be floated or towed to a disabled vessel that is not
able 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 by
tugs. After the tugs leave, the gates are closed, and the water in the
dry-dock is pumped out, leaving the boat high and dry. Large props are
put in place to prevent the boat from tipping.

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

The model here described does not possess all the fittings and additions
of 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 first
part to construct is the framework for the hull. Four pieces of wood
will be required for this, and they should be cut to the shape and size
shown in Fig. 121. To make this it is best to cut the two side parts
first, as indicated by the dotted lines. This done, the bottom piece can
be clamped on from behind by means of pieces of lath. These are for the
two end pieces. The other two pieces are made in the same way, except
that 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 inch
thick in order to accommodate the pieces used in the construction of the
remainder of the hull.

When the builder has made the four ribs, he should proceed to construct
the lower deck, which consists of a single piece of wood nicely planed
and finished, measuring 14-1/2 inches long by 8 inches wide and 1/8 inch
thick. This piece must be nailed to the bottom of each of the ribs, one
at each end, and the other two containing the holes at equal distances
apart. Tiny nails, similar to those used on cigar-boxes, will be found
very suitable for this work. Some old cigar-boxes may be broken apart to
obtain the nails for this purpose. Before nailing on the board it should
be marked out to present ordinary deck-boards. The reader is referred
back to Chapter 9 which describes this process, using a straight-edge
and knife.

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

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

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

[Illustration: FIG. 122]

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

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

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

As a trial the inlet-valve is now unscrewed and water is permitted to
enter 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 an
inch of the lower or inside deck. The valve should then be closed. The
exact position of the water should now be found, and a line drawn all
around the hull, which can afterward be painted in.

The engine and boilers must now be constructed and placed on the
dry-dock, so that the water that was permitted to enter may be pumped
out. As a temporary arrangement, a thin rubber tubing is inserted
through a hole in the lower deck and allowed to hang outside the
water-level. The siphon can then be formed by simply drawing the water
up by suction with the lips. A continuous flow will result, emptying the
hull 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 is
made in the top, and a brass or copper tube 6 inches long and about 3/4
inch in diameter is soldered in position, as depicted in Fig. 123. This
tube acts as a chimney on the dry-dock, but it is really used for
filling the boiler, and the top is supplied with a tightly fitting
cork.

The ends of the boiler also act as supports, and they are made 4 inches
long. The bottom edge is turned up for about 1/4 inch to enable the
boiler to be screwed firmly to the lower deck. The boiler occupies a
position 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 be
given of this particular part of the equipment. Before the boiler is
firmly fixed in place a small hole should be made near the top at one
end. The feed steam-pipe is inserted in this, and soldered in place.

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

The engine is set up as shown in Fig. 124. The first job is to make the
frame 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 to
accommodate the crank-axle _B_. Two holes must also be made for screws
to 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 crank
has a throw of 3/16 inch. The steam-cylinder is fixed on the outside of
one of the uprights, and the steam-pipe must, of course, be fitted from
the inside.

The pump-cylinder is composed of a small piece of brass tube 1 inch long
and 3/8 inch in diameter. The plunger is 1/2 inch long, and the diameter
is just sufficient to enable it to work freely up and down inside the
brass tube. One end is shaped as shown in Fig. 125. This contains a saw
cut that enables the pump-rod to be placed between and connected with a
pin. The bottom end of the cylinder is now fitted with a brass disk in
which a hole is made and a 3/32-inch tube soldered in place. The inside
surface of this piece of brass should be countersunk, and the piece is
then soldered into the end of the cylinder. Before the plunger is
inserted a small lead shot is dropped in, which should be larger than
the hole at the bottom of the cylinder, thereby covering it. A hole is
drilled in at the side of the cylinder, and a small bent pipe fixed in
it. At the top of this pipe a short piece of 3/8-inch brass tube is
fixed in place, as indicated. This piece of tubing is closed at both
ends. The bottom end is treated like that of the pump-barrel and
supplied with a large shot. An outlet-pipe is soldered into the side of
the delivery-valve chamber and leads to the side of the hull.

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

It is understood that two complete boilers and pump units are made for
the model, and one is mounted on each side. If the builder desires to
increase the capacity of the pumps and install a more powerful boiler
and engine, only one pump will be necessary. Otherwise the water will
not be pumped from the hull very rapidly.

When the builder has finished the pump units, he should turn his
attention 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. The
cab of each crane measures 2-1/2 inches high by 2 inches long by 1-3/4
inches wide. A small roof is fitted on, and a piece of wood fitted to
the bottom to serve as a floor. The jib measures 6 inches long by 3/4
inch at the base, and tapers to 1/2 inch. It has 1/4 inch turned down at
each side, thus adding considerable strength. The jib is fitted to the
cab by means of a wire passed through the sides, and two guy-ropes are
arranged as shown. A small piece is now cut out at the top, and a pulley
wheel 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 passes
through 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 means
of a small bolt and nut. A washer should be placed between the bottom of
the crane and the deck, to allow the crane to turn freely with little
friction.

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 purpose
of lighting up the interior of the engine-room. These are furnished from
top rings taken from gas-mantles. Anchor-chains are fixed at each end of
the dry-dock. The whole dry-dock is painted with two coats of gray paint
and 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 racing
type produces a far greater speed than would otherwise be possible.
Flash steam plants are far more complicated than ordinary
steam-propelled power plants, and for this reason the author devotes a
chapter to their description.

A considerable equipment of tools and not a little mechanical ingenuity
are 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 power
that speeds as high as thirty-five miles an hour have been reached by
boats measuring 40 inches long.

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

[Illustration: FIG. 128]

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

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

Notice the water-tank _G_. A little scoop, formed by a pipe of small
diameter, protrudes through the bottom of the boat, so that the forward
motion of the boat will cause water to rise in the tank _G_. An
overflow is also provided, so that, should the water not be sucked out
of the tank quickly enough, it will not flood the boat. The overflow
pipe hangs off the side of the boat.

The water pump _E_ sucks water from the tank, and pumps it through the
check-valve _K_ (this valve permits water to pass in one direction only)
into the boiler coils. The boiler coils, being red-hot, cause the water
to flash into steam the instant it reaches them. By the time the steam
has 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 the
steam passes into the steam-chest of the engine, and thence into the
cylinder, where it expands, delivering its energy to the piston.

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

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

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

Owing to the high temperature of the superheated steam, it is impossible
to use brass cylinders on the steam-engines employed with flash steam
systems. Steel seems to be the only cheap metal that is capable of
withstanding 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 to
prevent drafts of air from deflecting the flame from the center of the
boiler coils. The cover is provided with ventilators, so that the burner
will not be smothered. If enough oxygen does not enter the interior of
the boiler coils, poor combustion will result, and the gasolene flame
will not develop its maximum heat. Upon referring again to the diagram,
it will be seen that the exhaust steam pipe from the engine discharges
into the stack of the boiler covering. This discharge greatly
facilitates 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 once
adjusted they are easily disturbed by minor causes. Owing to the fact
that every square inch of surface in the flash coils is heating surface,
the amount of water supplied to the boiler must be exactly what is
needed. The heat must also be regulated so that the temperature of the
steam will just meet the engine's needs. Many times an increase in heat
causes the steam to reach such a temperature that it will burn up the
lubricating oil before it reaches the cylinder of the engine. This is
liable to cause trouble, because sticking is apt to occur.

Model power boats with speeds as high as thirty-five miles an hour have
been made in America. Such high-speed boats must be assembled with
infinite care, owing to the fact that the mechanism they carry is more
or less erratic in its action, and unless it is well made results cannot
be expected.

[Illustration: FIG. 129]

There are probably few sports more interesting than that of model
power-boat racing. The Central Park Model Yacht Club of New York city is
one of the most progressive clubs in America, and its members not only
have a sail-boat division, but they also have a power-boat division. The
members of the power-boat section have races regularly once a week, and
the most lively competition is shown. It is indeed amusing to watch
these little high-speed boats dash across the pond, their bows high in
the air and their little engines snorting frantically. Owing to the
difficulty of keeping these small racing boats in a straight line, they
are tied to a wire or heavy cord and allowed to race around a pole
anchored in the center of the pond, as illustrated in Fig. 129. The top
of the pole should be provided with a ball-bearing arranged so that the
cord to which the boat is fastened will not wind around the post. In
this way the boats are caused to travel in a circle, and as the cord to
which they are fastened represents the radius of the circle, the
circumference can readily be found by multiplying the radius by 2,
which will give the diameter. The diameter is then multiplied by 3.1416
to obtain the circumference. If the boats were permitted to travel wild
they would run into the bank, a fatal procedure when they are running at
high speed.

Speed boat hulls are usually of the hydroplane or sea-sled type. This
type 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 and
propeller 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 this
particular 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 conform
with the English racing rules. Next a bow piece is cut out, and this is
produced from solid wood. Only two materials are used in the
construction of this hull, aluminum and mahogany. Square mahogany strips
are cut out and fastened inside of the side pieces by means of shellac
and 3/8-inch brass brads. The bottom of the hull is made of 22-gage
sheet aluminum. This is fastened to the square mahogany strips, since
the sides of the boat are entirely too thin for this purpose. The method
of fastening the strips of aluminum will be made evident by referring to
Fig. 132. The aluminum bottom does not run completely over the bow
piece, but merely overlaps it sufficiently to be fastened by brass
brads, as illustrated in Fig. 135. The single step in the bottom of the
boat is fastened by a mahogany strip, through which the stern-tube runs
and the water-scoop. The back of the boat is made up of mahogany. A
small aluminum hood is bent to shape, and this is fastened to the bow of
the boat and prevents the boat from shipping water.

In building a hull of this nature the mechanic should exercise care to
see that it is in perfect balance, and that the sides are finished and
varnished as smoothly as possible. This will cut down both air and water
resistance. The position of the propeller strut and stern-tube will be
seen 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 of
the two-blade type. It should be at least 3 inches in diameter and with
a pitch of about 10 inches. By this it is meant that the propeller
theoretically should advance 10 inches through the water for one
revolution. The rudder is generally fastened in one position, in case
the 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 the
rudder can be entirely dispensed with.

[Illustration: FIG. 133]

The boiler of a flash steam plant is extremely simple. Such a boiler is
shown in Fig. 133. It consists merely of a coil of copper or Shelby
steel tubing with an internal diameter of 1/4 inch. The boiler coils
should be wound around a circular form of wood about 2-3/4 inches in
diameter. In the case of copper it will not be found very difficult to
do this, providing the copper is heated before being wound on the wooden
form. If the copper is heated it is advisable to wind the wood with a
layer of sheet asbestos before the copper tube is wound on. It is almost
necessary to do this winding with a lathe, but if the mechanic does not
have 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 work
done for a few cents. The boiler coil should be wound about 9 inches
long.

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

[Illustration: FIG. 134]

[Illustration: FIG. 135]

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




CHAPTER XIII

SAILING YACHTS


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

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

A sloop rig is illustrated in Fig. 137. By studying the drawing the
worker will see that the sloop rig differs from the cutter rig only in
that 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 small
sail set up on another mast abaft the mainsail. The sheet is led aft to
a spar that projects beyond the counter. The mast upon which the smaller
sail is set is known as the mizzenmast. In this rig it will be seen that
the main boom must be made considerably shorter than was the case in
the cutter rig. This is done so that it will not follow the mizzenmast
when it swings from one position to another.

[Illustration: FIG. 138]

[Illustration: FIG. 139]

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

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


_Model Yacht Parts_

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

Yachts always have an opening in the deck giving access to the interior
of the hull. These openings are known as hatchways. When sailing in
rough weather the hatchway is closed by a hatch to prevent the yacht
from shipping water.

The extreme forward end of a yacht hull is called the stern, while the
portions forward and aft of the midships section are known as the fore
and 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. These
portions are known as overhangs. The overhang aft is sometimes called
the counter-stern. The sides of the hull that rise above the deck are
called bulwarks, and the part of the bulwarks that cross the stern is
called the taffrail. The taffrail is always pierced with holes to allow
water to run off the deck quickly, so that the additional weight will
not in any way affect the course of the boat. It is understood that
yachts raise great quantities of water upon their decks when traveling
in rough sea.

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

[Illustration: A CUP-WINNING MODEL SAIL BOAT

Designed and constructed by the commodore of the Central Park Model
Yacht 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 that
rests on the mast is called the throat; the end of the gaff is called
the peak. The jib-boom is a term used only in connection with model
yachts. 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 the
bumpkin. The spar is rather a general term applied to practically all
wooden supports of sails. The spar of a lug-sail is called the yard. It
is different from a boom or gaff, by reason of its lying against the
mast instead of having one end butting on the mast. Anything belonging
to the mainmast should be distinguished by the prefix main. Thus, there
are the mainsail, the mainboom, main-topsail, etc.

[Illustration: FIG. 140]

A sail for a model cutter-rigged yacht is shown in Fig. 140. The
bowsprit and masts are, when necessary, given support by ropes that are
stretched tightly to some point where they can be conveniently anchored
to 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. The
halyards are fastened to the upper portions of the sail, and they are
named according to the sail to which they are attached. For instance,
there is the jib halyard and the foresail halyard. A mainsail carried by
a gaff has two halyards, the throat and peak. The movement of the sails
is controlled by ropes, called sheets, which take their names from the
sails they control. There is a mainsheet, a jibsheet, and a foresheet.
The reader should take note of this term and refrain from confusing it
with the sails.


_Sailing Model Yachts_

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

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

The cutter type of yacht will move against a wind that is blowing at a
very small angle on her bowsprit. As soon as she reaches the limit of
her course, the yachtsman turns her bow at a small angle so as to bring
the wind on the opposite side of the vessel, and in this way a second
course is started. These courses are repeated in a zigzag fashion until
the yacht arrives at her destination. This zigzagging, or "tacking," as
it is called, is illustrated in Fig. 141. It will be seen that the yacht
starts 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 a
new course, or "tack."

[Illustration: FIG. 141]

It will be understood that tacking is slow work, and a greater distance
must be traveled than would be covered by a power-boat, which would be
able to go in a straight line. However, with wind-propelled craft this
is the only way in which progress can be made against the wind. The
left-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 yacht
sailing 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 on
the starboard tack. From this the reader will see that Fig. 142 shows an
impossible 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 the
yacht act in such a manner as to turn the bows in the direction of the
arrow, as illustrated in Fig. 146, and the sail or sails abaft the mast
turn the boat in the direction of the arrow _A_. The boat thus revolves
upon the center of the mast much as a weathercock revolves upon its
pivot. If there is more than one mast, all the sails carried abaft the
mainmast serve to turn the boat in the direction _A_. The work of
sailing depends greatly upon the skill in balancing these two effects so
that the boat will progress in a straight line. To do this the sails are
set in a greater or less angle in relation to the center line of the
boat. The less the angle that a sail makes with the center line of the
boat, the greater is its power to determine in which direction the boat
will steer. The more the yachtsman slackens out his jib and foresail, or
the smaller he makes these sails, the less their power will be to turn
the boat in the direction _B_. On the other hand, the larger they are
and the more tightly they are pulled in, the greater will be their
power. When the mainsail and all of the sails abaft the mainsail are
slackened out and the smaller they are made, the less their power will
be to swing the boat in the direction _A_.

The influence of a sail upon the speed of a boat also increases with the
angle that it makes with the center line of the hull. The more the
yachtsman 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 good
for the young yachtsman to remember to sail his boat with the sails as
slack as possible, as long as she keeps a good course. He should also
remember not to overload her with sails, since the nearer to an upright
position she maintains the faster she will go.

It is not possible to depend entirely upon the trim of the sails to keep
a model in a given course. This is because the strength of the wind
varies so that the sails are in balance one moment and out of balance
the next. The sails abaft the mainmast overpower the sails before it
when the wind increases. The result of this is that the bow of the boat
will 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 overcome
this tendency of the yacht to "luff" in the wind. Fig. 147 shows the
course of a yacht reaching from _A_ to _B_. The dotted lines show the
course she should follow. The full line shows the effect of puffs of
wind, which repeatedly take her out of her course. Many times she may
completely turn around and make a similar course back to the
starting-point, as in Fig. 148. There is also the danger of her being
taken back when pointing directly against the wind--the wind will force
her 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 the
other.

The dotted line _B_ illustrates the course in which she would be driven
under these conditions. It is not practical to sail a model yacht dead
before the wind without an automatic rudder. With the use of an
automatic rudder the erratic movements shown in Fig. 148 can be entirely
overcome. The action of the rudder is such that every time the boat
leans over to luff up into the wind, the weight of the rudder causes it
to swing out, and thus prevents her from losing her course. As a
different type of rudder is required, according to the course in which
the yacht is sailing, the weight should be adjustable if the same rudder
is used.

[Illustration: FIG. 149]

[Illustration: FIG. 150]

[Illustration: FIG. 152]

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

[Illustration: FIG. 151]

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

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

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

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

By taking down the top-sail or setting a jib-head top-sail in place of a
jack yard top-sail, the yacht will be caused to ride easier in puffs of
wind. In case she does not point well to windward when beating, the
yachtsman should try a smaller jib, or he can slacken the
foresail-sheet. If she runs off regularly to leeward on one tack only,
while keeping well to windward on the other, she has some defect in
construction 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 designers
of model yachts, and the one here described can easily be constructed by
the 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_ valve
previously)

Page 185, "deterimental" changed to "detrimental" (detrimental to the
speed)





End of Project Gutenberg's Boys' Book of Model Boats, by Raymond Francis Yates