t.

A very important feature is that of self-righting. This is obtained by
having air chambers of large size, both at the bow and stern, placed
high above the centre of gravity. As the boat must be well ballasted,
she must have limited breadth of beam, as also limited side buoyancy.
By being properly ballasted, a boat can pass either through or over a
sea without being driven astern. The raised air chambers prevent the
sea breaking over her at the bow or stern; while, if she dips into the
sea, she instantly rises again. By having a limited beam, she gains in
speed, although she loses in stability; but, at the same time, if upset,
she is much more speedily righted; while shorter oars are required, and
fewer men to work them.

Papa was strongly in favour of the self-righting principle. The best
boats are diagonally built, and copper-fastened. The planks are of
mahogany, two thicknesses of half-inch board, with painted calico
between them. The keel is of American elm, and the false keel is one
piece of cast-iron, two and a half inches in width, by four and a half
in depth, weighing nine hundredweight. The stem is of English oak, and
the gunwale of American elm. The floors are of ash or oak. The deck is
of mahogany, well caulked, and seven-eighths of an inch in thickness.
These boats are about thirty-three feet in length over all, eight feet
in breadth, four feet in depth. They pull, when double-banked, ten
oars, which are made of ash, or sometimes fir; and they carry five or
six pairs of spare oars, to replace any which may be broken. They are
fitted with life-lines outside, by which the men, if thrown out of the
boat, can hold on to her, or people swimming can haul themselves on
board. No other boats are built so strongly. The principle adopted for
planking--that of placing the planks diagonally--gives the greatest
possible strength and elasticity, while the mahogany used is of the
best.

The lifeboats themselves are liable to disaster. They may be crushed by
falling masts, or driven right on board a wreck, or against rocks,
where, in spite of the efforts of their crews, they may be dashed to
pieces. It is now very rarely the case that lifeboats are lost. In
some places steamers are used to tow the lifeboat out to sea; but in
most instances she alone can approach a wreck sufficiently near to take
off the crew. The cost of establishing a lifeboat on a station is
estimated at eight hundred pounds, five