USS Pampanito after engine room sea water valves

A seacock is a

valve A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fitting ...

on the

hull Hull may refer to: Structures * Chassis, of an armored fighting vehicle * Fuselage, of an aircraft * Hull (botany), the outer covering of seeds * Hull (watercraft), the body or frame of a ship * Submarine hull Mathematics * Affine hull, in affi ...

of a

boat A boat is a watercraft of a large range of types and sizes, but generally smaller than a ship, which is distinguished by its larger size, shape, cargo or passenger capacity, or its ability to carry boats. Small boats are typically found on i ...

or a

ship A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished ...

, permitting water to flow into the vessel, such as for cooling an engine or for a

salt water Saline water (more commonly known as salt water) is water that contains a high concentration of dissolved salts (mainly sodium chloride). On the United States Geological Survey (USGS) salinity scale, saline water is saltier than brackish w ...

faucet; or out of the boat, such as for a sink drain or a toilet. Seacocks are often a

Kingston valve A Kingston valve is a type of valve fitted in the bottom of a ship's plating that connects the sea to the ship's piping and storage tanks. A Kingston valve is a type of seacock. It is arranged so that, under normal operating conditions, sea pre ...

. Seacocks are left open or are closed depending on the situation. Seacocks feeding into or out of a closed system, like the engine cooling system, are almost always left open. Seacocks connected to something open, such as a sink drain, might be opened up in

port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as H ...

but closed when at sea. The reason for this is that when the boat is level, the drain or other opening will always be above the

waterline The waterline is the line where the hull of a ship meets the surface of the water. Specifically, it is also the name of a special marking, also known as an international load line, Plimsoll line and water line (positioned amidships), that indi ...

, and so water will only flow out. At sea, when the boat rolls in the waves, the opening may sometimes be below the waterline. If the seacock is open, water may flood the boat, causing it to sink. Along the same lines, some seacocks on warships are designed to flood the ship when opened. Typically, this is done to magazines to prevent detonation of the ammunition in the event of fire, such as the case with , or to maintain trim due to battle damage (counterflooding). Additionally, opening the seacocks is one of the main methods used to scuttle a ship so that it cannot be captured by the enemy (for example in the

scuttling of the German fleet in Scapa Flow Shortly after the end of the First World War, the German Kaiserliche Marine was scuttled by its sailors while held off the harbor of the British Royal Navy base at Scapa Flow, in the Orkney Islands of Scotland. The High Seas Fleet was interned ...

in 1919).

References

Watercraft components {{Water-transport-stub