Seacock

A valve fitted to a through-hull opening so that water flow into or out of a vessel can be shut off.

Seacocks isolate systems such as engine cooling-water intakes, toilets, sinks and drains. They are normally mounted directly on, or securely connected to, a skin fitting and must be compatible with the hull, pipework and marine environment.

Each valve should remain accessible, identifiable and operable. The body, handle, hose, clips, backing and surrounding structure require inspection, and crew should know which position is open or closed and how to respond if a hose or fitting fails. A seacock reduces flooding risk only when the complete installation is sound and the valve can be closed.