Glossary of Marine Terms
P
padeye
a steel fitting formed by a flat doubler plate and vertical steel member containing a circular opening.
pelican hook
a hinged hook held closed by a ring and used to provide the quick release of an object which it holds.
person
as defined by section 1001 of the OPA, means an individual, corporation, partnership, association, state, municipality, commission, or political subdivision of a state, or any interstate body.
physical properties
those properties familiarly discussed in physics, exclusive of those described under mechanical properties; for example: density, electrical conductivity and coefficient of thermal expansion.
pickling
the process of removing hot rolled mill scale from billets, bars or hot rolled sheets with sulphuric or hydrochloric acid. the scale is removed for hot rolled pickled and oiled sheets or for further processing of the hot rolled steel product into cold drawn bars and wire and cold rolled sheets and strip.
pipe stanchion
a steel deck fitting consisting of a vertical post with angled bracket(s) on one side, welded to a doubler plate, which is welded on the deck of a vessel to restrain the movement of cargo, such as pipe.
plastic deformation
deformation of a material that will remain permanent after removal of the load which caused it.
Plimsoll mark
the primary loadline mark which is a circle intersected by a horizontal line accompanied by letters indicating the authority under which the loadline is assigned.
port
the left-hand side of a vessel when facing forward; a city having a harbor for vessels; a port hole.
precipitation hardening
a process of hardening an alloy in which a constituent precipitates from a supersaturated solid solution. this process is used for non-ferrous alloys to change the mechanical properties of the metal and is also called aging or age hardening.
propeller
a mechanical device having radiating blades which is mounted on a revolving, power-driven shaft for the purpose of propelling a boat; also called a screw or wheel.
proportional limit
same as elastic limit.
public vessel
as defined by section 311(a)(4) of the CWA, means a vessel owned or bareboat-chartered and operated by the United States, or by a state or political subdivision thereof, or by a foreign nation, except when such vessel is engaged in commerce.
push knee (tow knee)
a vertical, reinforced steel structure installed on a vessel to facilitate push towing. The height of the knee allows for variance in freeboard between vessels.
pushboat
a highly maneuverable, inland waters, shallow draft towboat usually designed with a square bow and towing knees which facilitate its primary method of towing which is pushing.
pv valve
pressure vacuum relief valve; a valve which automatically regulates the pressure or vacuum in a tank.
