B
Balanced Rudder: A rudder type in which a proportion of the rudder area, 25-30 % is forward of the axis of rotation. This is to reduce the required torque at the rudder stock.
Beam ends: When a vessel has heeled over to such an extent that there is no righting moment left to bring it back to the normal upright position. Also known as world ends or kiss your ass goodbye.
Beam: The maximum breadth of the vessel.
Belfast Bow: name given to raked stem introduced by Harland and Wolff of Belfast, giving a large foc’s’le deck.
Bilge: Curved portion, often circular, between bottom and side shell plating and the lower parts of holds, tanks and machinery spaces.
Bilge Keel: External fin at round of bilge to reduce rolling. May extend outwards from the vessel by up to 1 Metre in width. Extends fore and aft approximately 2/3 the length of the vessel.
Bilge radius: Radius of the shell plating that joins the side shell to the bottom shell of the hull, measured at the midships section.
Bilge strake: Continuous horizontal fore and aft strip of plating from stem to stern in way of the bilge.
Binnacle: Stand of wood or metal in which a compass is suspended. The cover protects the compass from weather and reduces glare from external lighting.
Bitt: Strong part of ships structure, generally based on the keel and attached firmly to a main deck to which a hawser or warp can be hitched when exceptionally heavy loads are applied such as when the vessel is being towed.
Bitter end: End of the anchor cable secured in the chain locker by a clench pin.
Block Coefficient: Ratio of the displacement of a ship to a given waterline and the volume of the circumscribing block having the same length, breadth and draught of the ship.
Bollard: Large and firmly secured post of circular section for securing hawsers and mooring ropes. Often fitted in pairs on the same base plate.
Boot Topping: Area of a ships side immediately above and below the deep load line. Particularly susceptible to marine weed growth and often coated with specially formulated anti-fouling paint.
Boss: Centre portion of propeller.
Bow: The forward end of the ship.
Bower anchors: The two largest anchors in a ship carried permanently attached to their cables, one on either side of the bow.
Bow thruster: Manoeuvring propeller installed at or near the bow, within a transverse tunnel, for docking assistance, or maintaining vessel heading.
Breadth moulded: Measured at midships and is maximum breadth over the frames.
Break: Point where a side shell plating section drops to the deck below such as in a poop or foc’s’le.
Breast hook: Triangular plate bracket joining port and stbd side stringers at the stem, holding both sides of the ship together.
Breast plate: Horizontal plate that connects shell plating at the stem.
Bridge: Superstructure erection above the freeboard deck generally extending to the ships side giving a clear view from which the ship can be manoeuvred.
Bridge wings: Open portion of the bridge extending from the wheelhouse to the side of the vessel.
Bulbous bow: Protruding bow below the waterline intended to reduce the vessels resistance to motion by breaking the creation of the wake.
Bulkhead: Vertical partition subdividing a ships interior into compartments.
Bulwarks: Vertical plating erected at the gunwhales of a ship to prevent persons being washed overboard and to reduce the water breaking over the deck in a seaway.
Bunker: Compartment where fuel oil or coal for ships engines or boilers is stored.
Buttock: Breadth of a ship where the hull rounds down to the stern.
Butt strap: Connecting metal strap covering a butt joint between two plates to give strength to the joint. |