P

Gas, such as nitrogen, kept above a liquid in a tank to maintain a protective blanket that excludes air and controls pressure.

The maintenance of a gas blanket (padding) over a cargo to keep air away from it, used for cargoes that react with oxygen or moisture.

A liquid coating that, when applied and dried, forms a protective and decorative film; marine paints protect against corrosion and fouling.

The formation of cracks in a paint film as it ages or is stressed, breaking its protective continuity.

A combination of coats (primer, intermediate, and finish) chosen to work together to protect a surface for its intended service.

A flat platform on which goods are stacked for handling as a unit by forklift.

A handling device or attachment used to lift and turn pallets during cargo operations.

The ship canal across the isthmus of Panama linking the Atlantic and Pacific oceans, whose lock dimensions define the Panamax ship size.

A shipboard oil pollution emergency plan tailored to meet the requirements for transiting the Panama Canal. IMO-grounded

An enclosed mooring chock of the type required for transiting the Panama Canal, through which mooring lines are led.

Bulk carriers built to the maximum size able to transit the Panama Canal locks, a standard size class in the dry-bulk trades.

A container ship sized to the maximum dimensions for transiting the Panama Canal locks.

A flat structural or finishing element; also a control or instrument panel.

The in-and-out flexing of the shell plating at the ends of a ship under the fluctuating water pressure of waves, resisted by panting stiffening.

A ship designed to carry paper and newsprint reels, with clean holds and handling gear suited to the cargo.

The portion of the hull amidships where the cross-section is constant and the sides are parallel, between the entrance and the run.

A cargo-handling system that loads from the side using parallel conveyors or platforms.

A system that detects and counteracts parametric roll, for example by advising speed and heading changes or by active means, to prevent the build-up of dangerous rolling.

A dangerous build-up of roll that can occur, especially in container ships and car carriers, when pitching in head or following seas periodically changes the ship's stability in step with its roll.

Large, rapidly building rolling caused by the periodic variation of stability as the hull pitches in waves, which can lead to cargo loss and damage.

A towed underwater device that uses its planing surfaces to hold a towed line or array out to the side, used in minesweeping and seismic survey.

Hatch covers that provide limited weather protection, used where full weathertightness is not required.

Fine solid and liquid particles emitted in engine exhaust, a pollutant of health concern increasingly addressed in air-emission controls. IMO-grounded

Every person aboard a ship other than the master, crew, and children under one year; the number of passengers determines whether a ship is a passenger ship under SOLAS. IMO-grounded

The spaces provided for the accommodation and use of passengers, subject to particular safety, escape, and fire-protection requirements under SOLAS. IMO-grounded

Ferries carrying both passengers and cars, combining passenger accommodation with vehicle decks.

The revenue-earning cargo a ship can carry, a part of its deadweight.

A mooring fitting with rollers mounted on a pedestal that guides a mooring line and reduces friction and wear as it leads.

Fish and other organisms living in the open water column rather than near the seabed, targeted by particular fishing methods and vessels.

A vessel with a main hull and four small sponsons, a multi-hull form intended to combine speed with stability.

A trade name for nitrile rubber, used for oil-resistant seals and gaskets.

The IMO standard, mandatory under SOLAS, specifying the surface preparation, coating systems, and inspection required for protective coatings in dedicated seawater ballast tanks and certain other spaces, to ensure a target coating life. IMO-grounded

The time a ship takes to complete one full roll from side to side and back, related to its stability and mass distribution.

The scheduled surveys of the hull structure (annual, intermediate, and special/renewal) required to maintain class and statutory certification. IMO-grounded

An electric motor that uses permanent magnets rather than wound field coils, offering high efficiency and compactness, used in some propulsion and auxiliary drives.

The permanent deformation remaining in a hatch-cover or other seal after prolonged compression, which can impair its sealing ability.

The proportion of a compartment's volume that can be occupied by water if it floods, a key factor in damage-stability and floodable-length calculations under SOLAS. IMO-grounded

A capsule used to transfer or evacuate personnel, for example between an offshore installation and a vessel or in an emergency.

A system for moving people safely off a ship or installation in an emergency, such as a marine evacuation system or escape chutes. IMO-grounded

Naturally occurring oil and gas hydrocarbons, the source of crude oil cargoes, fuels, and many products.

Gaseous hydrocarbons from petroleum, such as those carried by LPG carriers, which form flammable mixtures with air. IMO-grounded

Refined products of crude oil, such as gasoline, kerosene, diesel, and fuel oils, carried by product tankers.

Paints that form a film purely by the evaporation of solvent, without chemical reaction, so they can be redissolved by solvent.

A proprietary catamaran-based vessel or handling concept.

A structure projecting from the shore at which ships berth; see jetty.

A hatch cover panel that is lifted and stacked onto an adjacent panel to open the hatch.

The finely divided solids in paint that give it colour, opacity, and, in some cases, corrosion-inhibiting or anti-fouling properties.

A long column driven into the seabed to support a structure or to moor a vessel.

A vertical structural member that supports a deck and transfers its load to the structure below.

A person with local knowledge taken aboard to advise on the navigation of a ship in confined or difficult waters such as harbour approaches.

A small craft used to transfer pilots to and from ships.

A rope ladder rigged over the ship's side for a pilot to board and leave; its construction and rigging must meet SOLAS requirements and IMO standards for pilot transfer arrangements. IMO-grounded

A powered device formerly used to hoist a pilot aboard; mechanical pilot hoists are now prohibited by SOLAS in favour of ladders and combination arrangements. IMO-grounded

Platforms and shelters at the pilot boarding position providing safe access and protection during pilot transfer.

The act of navigating a ship through confined or hazardous waters, usually with a pilot aboard.

Tiny holes in a coating film, a defect that leaves the substrate locally unprotected and prone to corrosion.

Corrosion appearing as many small spots of rust where a coating has minute breaks, an early sign of coating breakdown.

The pins on which a rudder hangs and turns, fitting into the gudgeons on the sternpost.

The connectors and components, such as bends, tees, flanges, and reducers, used to join and route piping.

The connections between lengths of pipe, made for example by welding, flanges, or couplings.

Standard designations of pipe wall thickness for a given diameter, used to select piping for its pressure and service.

A protected passage running through the double bottom or holds carrying piping and allowing access and inspection.

A line of pipe for conveying fluids, aboard ship or, in offshore work, along the seabed.

Several pipelines grouped together, sometimes within an outer carrier pipe, laid as a unit on the seabed.

The structures at the ends of a subsea pipeline that connect it to wells, manifolds, or risers.

The complete arrangement of pipes, valves, and fittings for conveying a fluid.

Tubular conduits for conveying fluids through the ship's systems.

The individual parts of a piping system, including pipes, valves, fittings, and supports.

The arrangement of pipes, valves, pumps, and fittings that conveys a fluid for a particular service, such as bilge, ballast, fuel, or cooling.

The component that moves up and down within an engine cylinder, transmitting the force of combustion to the connecting rod.

The top of the piston, exposed to combustion, which transmits the gas pressure and must withstand high temperature.

A spring ring fitted in a groove around a piston that seals the combustion gases and controls the lubricating oil film against the cylinder wall.

The lower part of the piston that guides it in the cylinder and takes the side thrust in trunk-piston engines.

A proprietary sacrificial anode used for cathodic protection.

Localised corrosion that forms small, deep pits in an otherwise sound surface, which can perforate plating while overall thickness loss is small; a particular concern in tank bottoms.

A dredger that lifts loose seabed material by suction alone, without a cutter head.

Boards forming a deck or covering; also the wooden ceiling protecting a hold's tank top.

Maintenance carried out at predetermined intervals or running hours according to a programme, to prevent failures; planned maintenance schemes may be accepted in lieu of certain class surveys. IMO-grounded

A craft that rises and skims over the water surface at speed, supported mainly by hydrodynamic lift rather than buoyancy.

A facility or workstation used for planning cargo, voyages, or operations.

A cutting process using a high-temperature ionised gas jet (plasma) to melt and blow away metal, used for fast, clean cutting of plate.

A synthetic polymer material; also, in mechanics, deformation that is permanent rather than elastic.

Permanent change of shape of a material under load that remains after the load is removed.

The property of a material that allows it to undergo permanent deformation without fracture.

A solid transverse plate in the double bottom, running from the centre girder to the margin plate, that supports the inner bottom and stiffens the structure.

A compact heat exchanger made of many thin plates between which two fluids flow in alternate channels, giving efficient heat transfer.

An offshore vessel designed to carry supplies, equipment, and bulk materials to and from offshore installations, with a large clear deck and dynamic positioning.

The steel plates forming the shell, decks, and bulkheads of the hull.

A device towed along the seabed to bury a cable or pipeline in a trench it cuts.

A fitting used to close an opening, such as a drain plug in a tank bottom.

A valve operated by compressed air, commonly used in automatic control systems.

A system that moves dry bulk material, such as cement or grain, through pipes using a flow of air.

A streamlined housing beneath the hull containing a propulsion motor and propeller that can rotate to steer the ship; see azimuthing podded drive.

A satellite system in polar orbit that detects distress-beacon signals and relays them to rescue authorities, part of the Cospas-Sarsat system within the GMDSS. IMO-grounded

A substance that, if released, harms the marine environment; categories of pollutant and their control are defined in the annexes of MARPOL. IMO-grounded

The introduction of harmful substances or energy into the marine environment; its prevention from ships is the purpose of MARPOL. IMO-grounded

Booms, skimmers, sorbents, and storage used to contain and recover spilled oil or chemicals.

Vessels equipped to respond to marine pollution, recovering oil and treating contaminated water.

A large molecule built of repeating units, the basis of plastics, rubbers, and coating resins.

A versatile polymer used for tough, glossy coatings and for foams and elastomers.

A cellular plastic used for insulation and buoyancy, including in the insulation of liquefied-gas tanks and in some life-saving appliances.

A flat-decked float used for various purposes, including as a hatch cover, a floating platform, or a unit of a temporary structure.

A flat, liftable hatch cover panel removed by crane to open the hatch.

Hatch covers consisting of separate flat pontoon panels lifted on and off by crane.

A raised structure or deck at the stern of a ship.

The authority responsible for managing and regulating a port and its operations.

A location where the ship/port interface takes place, for which a security assessment and plan are required under the ISPS Code. IMO-grounded

The person responsible under the ISPS Code for the development, implementation, and maintenance of a port facility's security plan and for liaison with ship and company security officers. IMO-grounded

The port at which a ship is registered, shown on her stern and in her registration documents, establishing her nationality.

The left-hand side of a ship when facing forward.

A bulkhead that can be installed and removed to divide a space as needed, for example to separate parcels of cargo.

A transportable pressure chamber used to treat or decompress divers.

A round window in the ship's side or superstructure, fitted with a hinged glass and, below the freeboard deck, a deadlight, to maintain watertight integrity under the Load Line Convention. IMO-grounded

Under the Load Line Convention, the more exposed deck locations (on the freeboard and raised quarter decks, and on superstructure decks forward) for which the most stringent requirements apply to hatch covers and other closures. IMO-grounded

Under the Load Line Convention, the less exposed deck locations (on superstructure decks abaft a quarter of the ship's length from forward) for which somewhat less stringent closure requirements apply. IMO-grounded

A system that holds a floating unit on station by mooring lines and anchors, as an alternative or complement to dynamic positioning.

The controlled heating of a welded component after welding to relieve residual stresses and improve the properties of the weld and surrounding metal.

The time during which a mixed two-pack coating or adhesive remains usable after its components are combined.

To transfer a liquid; in metalworking, to pour molten metal into a mould.

The lowest temperature at which an oil will still flow; below it the oil becomes too stiff to pump, important for handling heavy fuels.

Finely divided solid material, such as dry chemical extinguishing powder or a powdered cargo.

The rate of doing work or transferring energy, for example the power developed by an engine.

The system that provides the power to operate a control element, such as the hydraulic system that drives the steering gear.

The generators, switchboards, transformers, and distribution equipment that provide and route electrical power aboard.

The generation and distribution arrangement supplying the thrusters and controls of a dynamic-positioning system, designed with redundancy to maintain position after a failure.

An automatic load-shedding arrangement that disconnects non-essential consumers first when generating capacity is threatened, to keep essential services supplied.

The heating of metal before welding to slow cooling and reduce the risk of cracking, especially in thick or hardenable steels.

The fitting-out of equipment, piping, and systems into structural blocks before they are erected, improving efficiency in modern shipbuilding.

Force per unit area exerted by a fluid or load.

Sealed chambers in which pressure can be raised or lowered, used for diving (hyperbaric) work and testing.

The supply of combustion air to an engine above atmospheric pressure, as by a turbocharger, to increase its power.

An instrument that measures the pressure of a fluid in a system.

A rapid rise in pressure in a pipeline, such as that caused by quickly closing a valve, which can damage the system if not controlled.

A process that separates gases by adsorbing one preferentially under pressure, used aboard to generate nitrogen for inerting. IMO-grounded

A cargo tank designed to hold its contents under pressure, as on a fully pressurised gas carrier, built to the IGC Code. IMO-grounded

A valve on a cargo tank that relieves both overpressure and vacuum, allowing the tank to breathe within safe limits while preventing flame entry, required in tanker venting arrangements. IMO-grounded

An arrangement that maintains a controlled pressure or atmosphere within a cargo hold, for example to keep it inert or dry.

A mandatory washing of certain chemical cargo tanks after discharge, with the residues delivered to reception facilities, required under MARPOL Annex II for the most hazardous substances. IMO-grounded

The main navigation equipment on the bridge, such as radar, ECDIS, gyrocompass, and position-fixing systems, required under SOLAS chapter V. IMO-grounded

Equipment that must operate continuously to maintain propulsion and steering, identified in the design of the electrical and machinery systems. IMO-grounded

The main strength members of the hull, such as the keel, girders, floors, and main frames, that carry the principal loads.

The engines or turbines that provide the mechanical power to drive the ship and its generators.

The first coat of a paint system, applied to the prepared surface to promote adhesion and corrosion protection for the coats that follow.

An approach to subdivision and damage stability that assesses the probability of surviving a range of possible damage cases, used in the SOLAS rules in place of the older deterministic method. IMO-grounded

The mixture of oil, gas, and water brought up from a well in offshore production.

A tanker designed to carry refined petroleum products, often with coated tanks and segregated systems to keep different grades separate; subject to MARPOL Annex I. IMO-grounded

The gradual spread of floodwater from one compartment to others through openings, piping, or structural failure, which can worsen a damaged ship's condition over time. IMO-grounded

Ships suited to carrying large, heavy, or unusually shaped items such as plant and equipment for industrial projects.

A sound signal of four to six seconds' duration, used in the sound signals prescribed by the collision regulations (COLREGs). IMO-grounded

A model test of a propeller running in undisturbed water to determine its thrust, torque, and efficiency characteristics independent of the hull.

A nitrogen generator using pressure-swing adsorption to separate nitrogen from air for inerting tanks and spaces. IMO-grounded

A manoeuvring test in which the rudder is returned to midships after a turn to check whether the ship has a tendency to continue turning, indicating directional stability. IMO-grounded

A power-electronic converter that controls voltage and frequency by rapidly switching, used in variable-speed electric drives including propulsion.