
A compartment is a portion of the space within a ship defined vertically between decks and horizontally between bulkheads. It is analogous to a room within a building, and may provide watertight subdivision of the ship's hull important in retaining buoyancy if the hull is damaged. Subdivision of a ship's hull into watertight compartments is called compartmentationWatertight subdivision limits loss of buoyancy and freeboard in the event of damage, and may protect vital machinery from flooding. Most ships have some pumping capacity to remove accumulated water from the bilges, but a steel ship with no watertight subdivision will sink if water accumulates faster than pumps can remove it. Standards of watertight subdivision assume no dewatering capability, although pumps kept in working order may provide an additional measure of safety in the event of minor leaks. The most common watertight subdivision is accomplished with transverse bulkheads dividing the elongated hull into a number of watertight floodable lengths. Early watertight subdivision tested with hoses sometimes failed to withstand the hydrostatic pressure of an adjoining flooded compartment. Effective watertight subdivision requires these transverse bulkheads to be both watertight and structurally sound