type. This
type of hull is extremely easy to make. Such a hull is shown in Fig.
130. It will be seen that it has an aluminum bottom. The propeller and
propeller strut will be noticed in this illustration.

[Illustration: FIG. 130]

[Illustration: FIG. 131]

[Illustration: FIG. 132]

The drawing for the particular hull shown in Fig. 130 is given in Fig.
131. First the two side pieces are cut out to the shape shown. In this
particular instance the over-all length of the sides is 39-1/3 inches.
This is called a meter boat, and is built with this length to conform
with the English racing rules. Next a bow piece is cut out, and this is
produced from solid wood. Only two materials are used in the
construction of this hull, aluminum and mahogany. Square mahogany strips
are cut out and fastened inside of the side pieces by means of shellac
and 3/8-inch brass brads. The bottom of the hull is made of 22-gage
sheet aluminum. This is fastened to the square mahogany strips, since
the sides of the boat are entirely too thin for this purpose. The method
of fastening the strips of aluminum will be made evident by referring to
Fig. 132. The aluminum bottom does not run completely over the bow
piece, but merely overlaps it sufficiently to be fastened by brass
brads, as illustrated in Fig. 135. The single step in the bottom of the
boat is fastened by a mahogany strip, through which the stern-tube runs
and the water-scoop. The back of the boat is made up of mahogany. A
small aluminum hood is bent to shape, and this is fastened to the bow of
the boat and prevents the boat from shipping water.

In building a hull of this nature the mechanic should exercise care to
see that it is in perfect balance, and that the sides are finished and
varnished as smoothly as possible. This will cut down both air and water
resistance. The position of the propeller strut and stern-tube will be
seen by referring to the drawing of the hull in Fig. 131.

The propeller of a high-speed boat is of a high pitch and generally of
the two-blade type. It should be at least 3 inches in diameter and with
a pitch of about 10 inches. By this it is meant that the propeller
theoretically should advance 10 inches through the water for one
revolution. The rudder is generally fastened in one position, in case
the boat is not used on a string and pole. It will be found advisable,
however, always to run the boat in this way, and in such cases the
rudder can be entirely disp