Flooding is the ingress of water into a vessel. Water may be intentionally introduced, either pumped into tanks or via gates/doors into a flooded space. Where there are openings in the effective watertight envelope of the hull, water will flow (flood) into the vessel until interior and exterior waterplanes are equalized.
- Ballast tanks - used to correct trim, heel, oppose moments or decrease roll
- Well decks - Used to launch and recover smaller vessels
- Moon pool, down hole - Used for diving, salvage, and drilling operations through the hull
- Sea chests, sea bays, box coolers, and other hull deductions - used primarily for cooling
- From attack, i.e., by mine or torpedo damage