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.

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.

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

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.

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