It is likewise his office to summon the crew to their duty; to assist with his mates in the necessary business of the ship; and to relieve the watch when it expires. He ought frequently to examine the condition of the masts, sails, and rigging, and remove whatever may be judged unfit for service, or supply what is deficient: and he is ordered by his instructions to perform this duty _with as little noise as possible_. BOB-STAY, _sous-barbe_, a rope used to confine the bowsprit of a ship downward to the stem, or cut-water. It is fixed by thrusting one of its ends through a hole bored in the fore-part of the cut-water for this purpose, and then splicing both ends together so as to make it two-fold, or like the link of a chain: a _dead-eye_ is then seized into it, and a _laniard_ passing through this and communicating with another dead-eye upon the bowsprit, is drawn extremely tight by the help of mechanical powers. See BOWSPRIT. The use of the bob-stay, is to draw down the bowsprit, and keep it steddy; and to counter-act the force of the stays of the fore-mast, which draw it upwards. The bowsprit is also fortified by shrouds from the bows on each side; which are all very necessary, as the foremast and the upper-part of the main-mast are stayed and greatly supported by the bowsprit. For this reason, the bob-stay is the first part of a ship’s rigging which is drawn tight to support the masts. To perform this task more effectually, it is usual to suspend a boat, anchor, or other weighty body, at the bowsprit-end, to press it downwards during this operation. BOLSTERS, a sort of small cushions or bags, filled with tarred canvas, laid between the collars of the stays and the edge of some piece of wood on which they lie: they are used to preserve the stays from being chafed or galled by the motion of the masts, as the ship rocks or pitches at sea. BOLT-ROPE, _ralingue_, a rope to which the edges or skirts of the sails are sewed, to strengthen, and prevent them from rending. Those parts of the bolt-rope which are on the perpendicular or sloping edges, are called leech-ropes; that at the bottom, the foot-rope; and that on the top or upper edge, the head-rope. Stay-sails, whose heads are formed like an acute angle, have no head-rope. To different parts of the bolt-rope are fastened all the ropes employed to contract or dilate the sails. The figure and position of the bolt-rope is exhibited in the plate referred to from the article SAIL. BOMB. See the articles MORTAR and SHELL. BOMB-VESSEL, a small ship particularly calculated to throw bombs into a fortress. They are said to be invented by M. Reyneau, and to have been first put in action at the bombardment of Algiers. Till then it had been judged impracticable to bombard a place from the sea. See a particular description of these ships in the article KETCH.