71. A Cleat.]

The dimensions of the mainsail are given in Fig. 169. For mast hoops we
used curtain rings. Five were attached to the sail along the luff, and
one was fastened with a piece of leather to the end of the gaff. We used
a different scheme for holding the boom to the mast. The forward end of
the boom was flattened at the sides and a couple of cheek blocks were
bolted on, forming jaws of the shape indicated in Fig. 170. The jaws
were whittled out to fit nicely around the mast, and were kept from
slipping off by a piece of rope passed around the mast and threaded
through the ends of the cheek blocks. Half a dozen small pulley blocks
were now procured, of the type used on awnings. A rope called the throat
halyard was strung from the throat or forward end of the gaff through a
pulley block near the top of the mast, and led down to the backbone,
where it was "belayed," or wrapped around a cleat. The cleat, which was
whittled out of a stick of wood, was made in the form indicated in Fig.
171. A short length of rope was strung through a pulley block and tied
with some slack to the upper end and to the center of the gaff. This
rope is called a "bridle," and to the pulley block on this "bridle" a
rope was attached called the "peak halyard." The peak halyard was passed
through a pulley block at the top of the mast, and belayed on a cleat at
the side of the backbone. For the main sheet (that is, the rope used for
guiding the mainsail) two pulley blocks were fastened to the backbone,
one just in front of the seat and the other a few feet further forward,
and two more were lashed to the boom, midway between these blocks. The
sheet was fastened near the aft end of the backbone and then strung
through the blocks in the order illustrated, the free end of the sheet
being brought back to the seat, where a cleat was provided, to which it
could be secured when desired.

[Illustration: Fig. 172. The Jib-sail.]

[Illustration: Fig. 173. The Ice Boat Completed.]

The jib-sail was now cut out to the dimensions given in Fig. 172. The
foot of the sail was lashed to a jib-boom 3 feet 4 inches long. The
jib-boom was attached to the backbone at its fore end by means of a
couple of screw eyes. The eye of one of these was pried open, linked
through the other and then closed again. One of the screw eyes was now
screwed into the head of the jib-boom and the other was threaded into
the end of the backbone. The upper corner or "head" of the