Floodability is the susceptibility of a ship's construction to flooding. It also refers to the ability to intentionally flood certain areas of the hull for damage control purposes, or to increase stability, which is particularly important in combat vessels, which often face the possibility of serious hull breach due to enemy action, and which rely on well-trained damage controlmen to equalize and then stop flooding of the hull.

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.