de, to keep them from flying out of their holes.--_Clench-bolts_ are
clenched with rivetting hammers.--_Fend_ or _fender bolts_, made with
long and thick heads, and struck into the outermost bends of the ship, to
save her sides from bruises.--_Forelock-bolts_ have at the end a forelock
of iron driven in, to keep them from starting back.--_Set-bolts_ are used
for forcing the planks, and bringing them close together.--_Ring-bolts_
are used for the bringing to of the planks, and those parts whereto are
fastened the breeches and tackle of the guns.--_Scarp-bolts_ and
_keel-bolts_, pointed, not clinched, used for false keel or temporary
purposes.--_Bringing-to bolts_, fitted with an eye at one end, and a nut
and screw at the other, for bringing to the ends at the stem, &c.--_To
bolt_, to start off, to run away.

BOLT-BOAT. An old term for a boat which makes good weather in a rough
sea.

BOLTING TIMBERS. Those on each side of the stem, continued up for the
security of the bowsprit. (_See_ KNIGHT-HEADS.)

BOLT OF CANVAS. The piece or roll of 39 yards in which it is supplied,
but which usually measure about 40 yards in length; it is generally from
22 to 30 inches wide.

BOLT-ROPE. A rope sewed all round the edge of the sail, to prevent the
canvas from tearing. The bottom part of it is called the foot-rope, the
sides leech-ropes, and if the sail be oblong or square the upper part is
called the head-rope; the stay or weather rope of fore-and-aft sails is
termed the luff.

BOLTROPE-NEEDLE. A strong needle for stitching the sail to the
bolt-ropes.

BOLT-SPRIT. _See_ BOWSPRIT.

BOLT-STRAKE. Certain strakes of plank which the beam fastenings pass
through.

BOLT-TOE. The cock of a gun-lock.

BOMB [formerly _bomber_, from _bomba_]. The mortar of bomb-vessels.

BOMB OR MORTAR VESSELS. Small ships fortified for throwing bombs into a
fortress; said to be the invention of M. Reyneau, and to have been first
used at the bombardment of Algiers in 1682. Until then it had been
judged impracticable to bombard a place from the sea.

BOMBALO. A delicate kind of sand-eel taken in quantities at Bombay.

BOMBARD. A piece of ordnance, anciently in use before the introduction
of more complete cannon with improved gunpowder, propelling iron balls.
Its bore, for the projection of stone shot, sometimes exceeded 20 inches
in diameter, but was short; its chamber, for containing the
powder-charge, being about as long, but much narrower both wi