Boys' Book of Model Boats Part 4

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 bra.s.s 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.

[Ill.u.s.tration: _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 bra.s.s screw is used to clamp it in position after setting it with the fingers. The rudder-shaft is a 3/4-inch bra.s.s 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.

[Ill.u.s.tration: _Jack Sussman_

ALL READY TO GO!

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

[Ill.u.s.tration: 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.

[Ill.u.s.tration: 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.

[Ill.u.s.tration: 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.

[Ill.u.s.tration: FIG. 65]

[Ill.u.s.tration: FIG. 67]

[Ill.u.s.tration: 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.

[Ill.u.s.tration: 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.

[Ill.u.s.tration: 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.

[Ill.u.s.tration: 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.

[Ill.u.s.tration: FIG. 71]

[Ill.u.s.tration: 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 ill.u.s.trated. 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 c.o.c.k-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.

[Ill.u.s.tration: FIG. 72]

[Ill.u.s.tration: FIG. 73]