Page:Popular Science Monthly Volume 91.djvu/485

 A Knock-Down Canvas Boat

���A KNOCK-DOWN canvas boat, 10 ft. in length, weighing complete less than 20 lb., capable of carrying 300 lb. and which may be made easily by any young man, is illustrated in the accompany- ing drawings. The entire frame is made of either spruce or birch, the latter preferred, the material being in strips % in. thick and I Y2 in. wide. The widest pieces are the seats and keel boards, all of which are 5 in. with a thickness of ^ in.

The illustration does not show the canvas, as the manner of constructing the frame is the important thing to be considered. When made according to directions it will be found very rigid, even before the canvas is applied. The bulging shape of the keel and the midship section of the canoe have a wonderful stabilizing action on the craft when it is in motion.

Two pieces of keel strips A are provided, each 6 ft. long from the center of one hole to the center of the other. To each end of the two parallel keel strips thus described is attached a keel extension strip B, each of which is 26 in. from hole to hole. Each hole in these strips is to be bored with a %-in. bit, and bolts 2% in. long should be used. Suitable washers should be used behind each bolt-head or nut and properly sunk into the surface of the wood so the head and nut will fit evenly.

Eleven keel boards, each 6^ in. long, are ranged along the two parallel keel strips, the keel strips being spread apart in the middle so they measure 6 in. from outside to out- side. The keel boards C are then laid on evenly and nailed to the keel strips, thereby providing a suitable runway for the occupants of the canoe.

��The side, or gunwale strips D, are 6 ft. long, each end being cut off square on a vertical line, but on an angled line in a horizontal direction. To each end is fitted a side extension bar E, by means of a hinge, the opposite end having a hole 24.3/2 in. from the angled end. These extension bars are joined at their ends to the end of the keel extension. The three lapped ends are secured by a bolt.

It is now necessary to join the keel portion with the gunwale frame. A span frame for each end of the canoe, and a pair of span frames provided with seats are placed midway between the end spans. The frame for the ends is made of a top cross-piece G, of material % in. thick and 2 in. wide, which indicates the dimensions of all the parts of the span frames. Each cross- piece of the two end frames is 22 in. long, each end having a cut-out portion ij^ by % in. in which the side pieces D rest. A hole through the side piece and end of each cross-piece permits a pin to be driven in to hold the parts together until the canvas is applied. The fabric will prevent the pin from coming out.

Two V-shaped pieces extend down from the ends of the cross-piece, the lower ends being held together by a short cross-piece. The ends of the V-pieces are cut so they span the keel strips, while the short cross- piece rests on the keel strips and thus serves as a support for the upper frame- work. The seats F are each 30^ in. long, and at each end is a cross-strip or cleat,

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