"Compartmentation" redirects here. For compartmentation in structures for the purpose of limiting the spread of fire, smoke and flue gases, see Fire compartmentation.
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 compartmentation.
Transverse bulkheads appear horizontally in this photo of the battleship USS South Dakota (BB-57) under construction.These compartments are formed by non-structural bulkheads.