Ballast is material that is used to provide stability to a vehicle or structure. Ballast, other than cargo, may be placed in a vehicle, often a ship or the gondola of a balloon or airship, to provide stability. A compartment within a boat, ship, submarine, or other floa

A bilge pump is a water pump used to remove bilge water. Since fuel can be present in the bilge, electric bilge pumps are designed to not cause sparks. Electric bilge pumps are often fitted with float switches which turn on the pump when the bilge fills to a set level.

A hovercraft, also known as an air-cushion vehicle or ACV, is an amphibious craft capable of travelling over land, water, mud, ice, and other surfaces.

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Hovercraft use blowers to produce a large volume of air below the hull, or air cushion, that is slightly above atmosp

Port and starboard are nautical terms of orientation that deal unambiguously with the structure of vessels and aircraft, referring respectively to the left and right sides of the vessel, seen by an observer aboard the aircraft or vessel looking forward.

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Vessel structu