arc a vane is attached for
sight,--to the second one for shade,--and at the vertex the horizontal
vane has a slit in it.

BACKSTAY-PLATES. Used to support the backstays.

BACKSTAYS. Long ropes extending from all mast-heads above a lower-mast
to both sides of the ship or chain-wales; they are extended and set up
with dead eyes and laniards to the backstay-plates. Their use is to
second the shrouds in supporting the mast when strained by a weight of
sail in a fresh wind. They are usually distinguished into breast and
after backstays; the first being intended to sustain the mast when the
ship sails upon a wind; or, in other terms, when the wind acts upon a
ship obliquely from forwards; the second is to enable her to carry sail
when the wind is abaft the beam; a third, or shifting backstay, is
temporary, and used where great strain is demanded when chasing, chased,
or carrying on a heavy pressure of canvas: they are fitted either with
lashing eyes, or hook and thimble with selvagee strop, so as to be
instantly removed.

BACKSTAY-STOOLS. Detached small channels, or chain-wales, fixed abaft
the principal ones. They are introduced in preference to extending the
length of the channels.

BACKSTERS. Flat pieces of wood or cork, strapped on the feet in order to
walk over loose beach.

BACK-STRAPPED. As a ship carried round to the back of Gibraltar by a
counter-current and eddies of wind, the strong currents detaining her
there.

BACK-SWEEP. That which forms the hollow of the top-timber of a frame.

BACK-WATER. The swell of the sea thrown back, or rebounded by its
contact with any solid body. Also the loss of power occasioned by it to
paddles of steamboats, &c. The water in a mill-race which cannot get
away in consequence of the swelling of the river below. Also, an
artificial accumulation of water reserved for clearing channel-beds and
tide-ways. Also, a creek or arm of the sea which runs parallel to the
coast, having only a narrow strip of land between it and the sea, and
communicating with the latter by barred entrances. The west coast of
India is remarkable for its back-waters, which give a most useful smooth
water communication from one place to another, such as from Cochin to
Quilon, a distance of nearly 70 miles.

BACON, TO SAVE. This is an old shore-saw, adopted in nautical
phraseology for expressing "to escape," but generally used in _pejus
ruere_; as in Gray's _Long Story_. (_See_ FOUL HAWSE.)

BAD-BERTH. A f