=barge=—A general name given to most flat-bottomed craft. In ancient and mediæval times the name was given also to large boats of state or pleasure, and in later days to one of the small boats of a man-of-war. The barges of to-day are of various descriptions, being either sea-going, river, or canal. =barkentine=—A three-masted sailing vessel, square rigged on the fore- and mainmasts, and fore and aft rigged on the mizzen. For illustration see page 201. =barometer=—An instrument for measuring the weight or pressure of the atmosphere. A careful study of its changing record makes it possible to foretell many of the changes in the weather. =batten=—A long strip of wood. Battens are used for many purposes, such as covering seams inside the hull. To _batten_ down—To cover up tightly; usually spoken of hatches when they are closed tightly. =battle cruiser=—A large and very powerful fighting ship, of high speed, and with an armament equal or superior to that of a battleship, but very lightly armoured. =beam=—The width of a vessel at her widest part. =bearing=—The direction, or angular distance from a meridian, in which an object lies. =beat=—To _beat_ to windward is to make progress in a sailing vessel in the direction from which the wind is blowing. =belay=—To make fast; as, to _belay_ a rope. =belaying pin=—A movable pin or bolt of wood or metal to which lines are belayed. =below=—To _go below_ is equivalent, on shipboard, to going downstairs. =berth=—A bed or bunk on board ship; a place for a ship to tie up or anchor is sometimes called a berth. =between decks= or =’tween decks=—Any place below the main deck on a ship of more than one deck. =bilge=—That part of the hull of a ship inside and adjacent to the keel. =bilge keel=—Fins of wood or steel approximately paralleling the keel but built into and projecting from the ship at about where the bottom and the sides might be said to join. They are intended to minimize the rolling of the ship. =bilge water=—Water that collects in the bottom of the ship. As this is always at the lowest part of the hull, oil and other impurities are always a part of the bilge water, with the result that its odour is generally offensive and it is very dirty. =binnacle=—The fixed case and stand in which the steering compass of a vessel is mounted. =bireme=—An ancient ship, driven by two banks of oars. =bitts=—Posts of metal or timber projecting from the deck, to which lines may be made fast. =Blackwall hitch=—A knot. For illustration see page 193. =block=—A pulley used on board ship. =boat=—A small vessel. It is improper to refer to large ships as boats. =bob stay=—A stay or rope made fast to the stempost of a ship at the cutwater and leading to the end of the bowsprit. =bolt-ropes=—The ropes along the borders or edges of a sail for the purpose of strengthening those parts.