Fig. 82.
A Working Motor Boat.—To construct a motor boat that will travel a considerable distance is not really a difficult matter. All that is necessary is a piece of board for a hull, a wood or metal propeller, and a yard or two of strong elastic: these, carefully adjusted, will do all that is necessary.
For the hull, a piece of 5/8 in. or 3/4 in. board, about 18 in. long will do. This can be cut to the boat shape by means of a pocket knife or a spokeshave, and finished off with glass-paper. It should be sharp-pointed at the bows, about 3 in. to 4 in. at the centre, tapering down to a width of 2 in. at the stern. In the centre of the hull nail a block of wood, and to it glue two funnels (Fig. 83). For these, the odd lengths cut off from bamboo curtain poles will do admirably; or, if these be not obtainable, a couple of incandescent-mantle cases will suffice.
Fig. 83.
The adjustment of the motive power is the difficult task. First, you will need to purchase a couple of yards of suitable elastic: this is sold at most large toy shops, and costs usually a penny a yard. To fix this into place beneath the hull you will need to construct two metal supports. If you can get an old tin box made from metal sufficiently stout, that will do; if not, then you had better buy a piece of sheet brass, No. 20 gauge: 6 in. by 4 in. will be ample. Draw out these supports as shown in Figs. 84 and 85, and bend them into shape as in Figs. 86 and 87—one for the bow and one for the stern. Screw on the bow one about 1-1/2 in. or 2 in. from the point, and the stern one in the middle of the end.
Fig. 84.