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.