Boys' Book of Model Boats Part 6

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.

[Ill.u.s.tration: FIG. 86]

[Ill.u.s.tration: FIG. 87]

[Ill.u.s.tration: 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.

[Ill.u.s.tration: FIG. 90]

[Ill.u.s.tration: FIG. 91]

[Ill.u.s.tration: 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 bra.s.s 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 bra.s.s bushing held in a bracket made of a strip of bra.s.s 1/2 inch wide. The bra.s.s strip is wound around the bushing and soldered. It is held to the bottom of the hull by means of two 8-32 bra.s.s 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.

[Ill.u.s.tration: FIG. 93]

[Ill.u.s.tration: FIG. 92]

The two dry batteries for the motor are held in two tin troughs, as ill.u.s.trated 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 ill.u.s.trated 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 bra.s.s rod. A hole is drilled through this rod with a small drill and a piece of copper wire is inserted. A square piece of bra.s.s 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 bra.s.s, as ill.u.s.trated. Three holes are drilled in the bearing bracket, two through which the wire pa.s.ses 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.

[Ill.u.s.tration: 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 ill.u.s.trated 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 tr.i.m.m.i.n.gs 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 bra.s.s 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 bra.s.s 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.

[Ill.u.s.tration: FIG. 95]

[Ill.u.s.tration: 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.

[Ill.u.s.tration: FIG. 98]

[Ill.u.s.tration: 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 bra.s.s 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 bra.s.s 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 bra.s.s 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 bra.s.s 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 bra.s.s 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 bra.s.s 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 bra.s.s screw pa.s.ses through these and into the deck of the boat. The bra.s.s screw should not be driven in too far, since the bollards should be free to revolve. It is also possible to use bra.s.s tubing instead of wood if the proper size is in the model-builder's shop.

[Ill.u.s.tration: 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.

[Ill.u.s.tration: 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]