AXLE-TREES. The two cross-pieces of a gun-carriage, fixed across and under the fore and hinder parts of the cheeks. The cylindrical iron which goes through the wheel of the chain-pump, and bears the weight of it.
AYE, AYE, SIR. A prompt reply on receiving an order. Also the answer on comprehending an order. _Aye-aye_, the answer to a sentinel's hail, from a boat which has a commissioned officer on board below the rank of captain. The name of the ship in reply from the boat indicates the presence of a captain. The word "flag," indicates the presence of an admiral.
AYR. An open sea-beach, and also a bank of sand. (_See_ AIRE.) The mediæval term for _oar_.
AZIMUTH. A word borrowed from the Arabic. The complement of the amplitude, or an arc between the meridian of a place and any given vertical line.
AZIMUTH COMPASS. A superior graduated compass for ascertaining the amount of magnetic variation, by amplitude or azimuth, when the sun is from 8° to 15° high, either after its rising or before its setting. (_See_ MAGNETIC AZIMUTH.) It is fitted with vertical sight vanes for the purpose of observing objects elevated above the horizon.
AZOGUES. Spanish ships fitted expressly for carrying quicksilver.
AZUMBRE. A Spanish wine-measure, eight of which make an arroba.
AZURE. The deep blue colour of the sky, when perfectly cloudless.
BAARE-Y-LANE. The Manx or Gaelic term for high-water.
BAAS. An old term for the skipper of a Dutch trader.
BAB. The Arabic for _mouth_ or _gate_; especially used by seamen for the entrance of the Red Sea, _Bab-el-mandeb_.
BABBING. An east-country method of catching crabs, by enticing them to the surface of the water with baited lines, and then taking them with a landing net.
BABBLING. The sound made by shallow rivers flowing over stony beds.
BAC. A large flat-bottomed French ferry-boat. In local names it denotes a ferry or place of boating.
BACALLAO [Sp.] A name given to Newfoundland and its adjacent islands, whence the epithet is also applied to the cod-fish salted there.
BACCHI. Two ancient warlike machines; the one resembled a battering-ram, the other cast out fire.
BACK. _To back an anchor._ To carry a small anchor ahead of the one by which the ship rides, to partake of the strain, and check the latter from coming home.--_To back a ship at anchor._ For this purpose the mizen top-sail is generally used; a hawser should be kept ready to wind her, and if the wind falls she must be hove apeak.--_To back and fill._ To get to windward in very narrow channels, by a series of smart alternate boards and backing, with weather tides.--_To back a sail._ To brace its yard so that the wind may blow directly on the front of the sail, and thus retard the ship's course. A sailing vessel is backed by means of the sails, a steamer by reversing the paddles or screw-propeller.--_To back astern._ To impel the water with the oars contrary to the usual mode, or towards the head of the boat, so that she shall recede.--_To back the larboard_ or _starboard oars_. To back with the right or left oars only, so as to round suddenly.--_To back out._ (_See Back a Sail._) The term is also familiarly used for retreating out of a difficulty.--_To back a rope or chain_, is to put on a preventer when it is thought likely to break from age or extra strain.--_To back water._ To impel a boat astern, so as to recede in a direction opposite to the former course.--_Backing the worming._ The act of passing small yarn in the holidays, or crevices left between the worming and edges of the rope, to prevent the admission of wet, or to render all parts of equal diameter, so that the service may be smooth.--_Wind backing._ The wind is said to back when it changes contrary to its usual circuit. In the northern hemisphere on the polar side of the trades, the wind usually changes from east, by the south, to west, and so on to north. In the same latitudes in the southern hemisphere the reverse usually takes place. When it backs, it is generally supposed to be a sign of a freshening breeze.