The head (pl. heads) is a ship's toilet. The name derives from sailing ships in which the toilet area for the regular sailors was placed at the head or bow of the ship.

Design

In sailing ships, the toilet was placed in the bow somewhat above the water line with vents or slots cut near the floor level allowing normal wave action to wash out the facility. Only the captain had a private toilet near his quarters, at the

stern The stern is the back or aft-most part of a ship or boat, technically defined as the area built up over the sternpost, extending upwards from the counter rail to the taffrail. The stern lies opposite the bow, the foremost part of a ship. Ori ...

of the ship in the quarter gallery. The plans of 18th-century naval ships do not reveal the construction of toilet facilities when the ships were first built. The Journal of Aaron Thomas aboard HMS ''Lapwing'' in the Caribbean Sea in the 1790s records that a canvas tube was attached, presumably by the ship's sailmaker, to a

superstructure A superstructure is an upward extension of an existing structure above a baseline. This term is applied to various kinds of physical structures such as buildings, bridges, or ships. Aboard ships and large boats On water craft, the superstruct ...

beside the bowsprit near the figurehead, ending just above the normal waterline. In many modern boats, the heads look similar to seated flush toilets but use a system of valves and

pump A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic energy. Pumps can be classified into three major groups according to the method they u ...

s that brings sea water into the toilet and pumps the waste out through 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 ...

(in place of the more normal

cistern A cistern (Middle English ', from Latin ', from ', "box", from Greek ', "basket") is a waterproof receptacle for holding liquids, usually water. Cisterns are often built to catch and store rainwater. Cisterns are distinguished from wells by t ...

and

plumbing trap In plumbing, a trap is a U-shaped portion of pipe designed to trap liquid or gas to prevent unwanted flow; most notably sewer gases from entering buildings while allowing waste materials to pass through. In oil refineries, traps are used to p ...

) to a drain. In small boats the pump is often hand operated. The cleaning mechanism is easily blocked if too much toilet paper or other fibrous material is put down the pan.

Submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...

heads face the problem that at greater depths higher water pressure makes it harder to pump the waste out through the hull. As a result, early systems could be complicated, with the head fitted to the United States Navy S-class submarine being described as almost taking an engineer to operate. Making a mistake resulted in waste or seawater being forcibly expelled back into the hull of the submarine. This caused the loss of . The toilet on the World War I British E-class submarine was considered so poor by the captain of that he preferred the crew to wait to relieve themselves until the submarine surfaced at night. As a result, many submarines only used the heads as an extra storage space for provisions. Aboard sailing ships and during the era when all hands aboard a vessel were men, the heads received most of their use for defecation; for routine urination, however, a

pissdale A pissdale (also written piss-dale and piss dale) is a lead basin or trough that was fitted to the insides of the bulwarks on sailing ships which served as a urinal for the men aboard these ships. The pissdale was a 17th-century engineering devel ...

was easier to access and simpler to use. File:Heads on HMS alliance.jpg, Head in British submarine (c.1945–1973) File:FoxTrot 480 0071.JPG, Head in Soviet submarine of the (c.1957–1983) File:USS Growler - Toilet (7181617746).jpg, Head in submarine (mid-1950s)

References

{{Toilets Ship compartments Toilets