The waterproof door closes hermetically, forming a barrier against the passage of air or water.
Waterproof doors are used on ships to prevent flooding in case of a leak or to prevent the spread of fire.
A waterproof door can be operated manually via a lever. Some models use hydraulic or electrical systems, or a combination of the two. While some are operated directly, others can be activated remotely from the bridge or another location fitted with controls. Generally, those using a mechanical system are sliding models.
Choice will depend on door size and location, the operating mechanism and the number of doors needed to ensure vessel stability in case of flooded compartments.