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A proprietary man-overboard recovery device, a frame or scoop lowered over the side to lift a person from the water back aboard a vessel.

A diagram presenting the consequences of assumed damage to a ship, such as the extent of flooding and its effect on stability, to support damage-control decisions.

The information provided to the crew to help them assess and respond to flooding after damage, including the effect on the ship's buoyancy and stability. IMO-grounded

A manual carried aboard, required for certain ships under SOLAS, giving the master information and instructions for maintaining the ship's stability and integrity following flooding damage. IMO-grounded

A plan, required by SOLAS, showing the boundaries of watertight compartments, the openings in them with their means of closure, and the arrangements for correcting list due to flooding, for use in a damage emergency. IMO-grounded

The team of crew members organised and trained to respond to flooding and damage, taking action to limit and counter its effects.

The assumed extent of damage to the hull, longitudinally, transversely, and vertically, used in damage-stability calculations to assess survivability. IMO-grounded

Calculations that determine whether a ship will remain afloat and adequately stable after assumed flooding, carried out to demonstrate compliance with the damage-stability requirements of SOLAS. IMO-grounded

The assessment of a tanker's ability to survive flooding after damage, to the standards set for chemical tankers in the IBC Code and for oil tankers under MARPOL and SOLAS. IMO-grounded

A survey carried out to assess the nature and extent of damage to a ship after a casualty, to determine repairs and seaworthiness.

Information showing how a ship will behave and survive in assumed damage conditions, supporting both design assessment and onboard damage control. IMO-grounded

Harm to the marine environment, such as that caused by oil or chemical pollution, the prevention of which is the purpose of MARPOL and related instruments. IMO-grounded

The dissipation of energy that reduces the amplitude of an oscillation or vibration over time, for example the damping of a ship's roll by bilge keels.

An area in which a flammable or explosive atmosphere may be present, requiring certified safe equipment and special precautions, as on tankers and gas carriers. IMO-grounded

A document listing the dangerous goods carried aboard, with their classification and stowage positions, required under SOLAS for ships carrying such cargoes. IMO-grounded

Substances and articles that pose a hazard in transport, such as explosives, gases, flammable, toxic, corrosive, and radioactive materials; their carriage by sea in packaged form is governed by the IMDG Code, mandatory under SOLAS. IMO-grounded

The nine classes into which the IMDG Code groups dangerous goods according to their principal hazard, from explosives (Class 1) to miscellaneous dangerous substances (Class 9). IMO-grounded

A Danish testing and certification body for fire safety and security technology.

A device that automatically records measured data over time, used aboard to monitor and keep records of machinery and system parameters.

A small, fast boat carried by and launched from a larger vessel, used for tasks such as rescue, survey, or transferring personnel.

An inflatable liferaft designed to be launched by a davit so that survivors can board it at deck level before it is lowered, as required for certain ships under SOLAS and the LSA Code. IMO-grounded

The cranes or arms fitted at a ship's side to hold, swing out, and lower survival craft or boats; their design and operation are covered by SOLAS and the LSA Code. IMO-grounded

A hinged metal cover fitted over a sidescuttle (porthole) that can be closed to protect the glass and maintain watertight integrity in heavy weather. IMO-grounded

The condition in which the main propulsion plant, boilers, and auxiliaries are out of action with no power available, from which SOLAS requires that the ship be able to restore propulsion and essential services without outside help. IMO-grounded

The slowest ahead or astern speed of the engine, used for delicate manoeuvring.

The rise of the bottom of the hull from the keel to the bilge, measured as the angle or height by which the bottom slopes upward toward the side.

The total mass a ship can carry, including cargo, fuel, stores, water, crew, and effects, equal to the difference between the loaded and light displacements.

A scale or table relating a ship's draught to its displacement and deadweight, used to estimate loading.

The solid part of the hull at the lower stern (or stem) where the form narrows to almost no breadth, near the keel.

A device that removes dissolved gases, especially oxygen, from boiler feed water to reduce corrosion in the boiler and feed system.

A logarithmic unit for expressing the ratio of two values of a quantity such as sound or power, used to measure sound and noise levels aboard ship.

A horizontal structural platform extending across the ship, forming a floor of a space and contributing to the strength and watertight integrity of the hull.

The machinery on the upper deck used for mooring, anchoring, and cargo work, such as windlasses, capstans, winches, and cranes.

A transverse member supporting a deck and the loads upon it, tying the two sides of the ship together.

Cranes mounted on deck for handling cargo or equipment.

A pressure chamber on the deck of a diving support vessel in which divers are compressed, decompressed, and accommodated during saturation diving.

The collective term for the machinery serving deck and hull functions, including anchoring, mooring, steering, and cargo-handling equipment.

The deck crew, the seamen who carry out the work of the deck department.

A longitudinal member supporting the deck beams and contributing to the strength of the deck and the hull girder.

The official record kept on the bridge of a ship's navigation, weather, and significant events during each watch.

A certificated officer of the deck department responsible for navigation, cargo, and the safe operation of the ship under the master. IMO-grounded

The plating forming the deck, which contributes to the strength of the hull girder, particularly the strength deck.

A water seal in the inert-gas system that prevents cargo-tank gases from flowing back to the machinery space, an essential safety component on tankers. IMO-grounded

A ship arrangement or term relating to the carriage of cargo on deck; loosely, a vessel carrying substantial deck cargo.

The outboard strake of deck plating, connecting the deck to the side shell, an important strength member at the deck edge.

The assembly of deck plating, beams, girders, and pillars that forms a deck and carries its loads.

A tank situated on deck rather than within the hull, used for storage of liquids such as fuel, water, or certain cargoes.

A member of the deck crew who carries out general seamanship duties.

A structure built on a deck, with its sides set in from the ship's side, providing accommodation, navigation, or service spaces.

An agreement between a ship and a port facility, or between ships, recording the security measures each will take, used under the ISPS Code in certain circumstances. IMO-grounded

The loss of bonding or separation within or between materials, such as the separation of a coating from its substrate or failure within a material.

The installation of pipelines on the seabed in deep water, requiring specialised lay vessels and techniques to control the pipe during deployment.

Shipping trades involving long ocean voyages between distant ports, as opposed to short-sea or coastal trades.

Cargo pumps mounted at the bottom of a tank with the driving motor on deck and a long shaft, used on chemical and product tankers to keep different cargoes separate.

Any imperfection in a weld, such as porosity, lack of fusion, cracks, or undercut, that may reduce its strength or integrity.

A weld containing defects severe enough to fail to meet the acceptance criteria, requiring repair.

A change in the shape or dimensions of a body under load, which may be elastic (recoverable) or permanent (plastic).

The removal of moisture from air to control humidity, used to protect spaces, cargo, and equipment from condensation and corrosion.

Equipment that reduces the moisture content of air, by cooling or by adsorption, to control humidity in protected spaces.

The separation of a layered material into its layers, such as the peeling apart of a laminate or the separation of a coating from its substrate.

Fish and other organisms that live on or near the seabed, as distinct from pelagic species of the open water; relevant to the design of fishing vessels.

A proprietary marine product or system designation.

Technology for reducing the nitrogen-oxide content of engine exhaust gas, such as selective catalytic reduction, used to meet the NOx limits of MARPOL Annex VI. IMO-grounded

The mass of a substance per unit volume, a fundamental property affecting buoyancy, cargo measurement, and fluid behaviour.

Localised corrosion occurring beneath deposits on a metal surface, where a sheltered, aggressive local environment forms.

The vertical distance from the top of the keel to the underside of the freeboard deck at the side, measured amidships, a principal dimension of the ship.

The distance to which the parent metal is melted and fused during welding, indicating how well the weld has penetrated.

The reduction of an engine's maximum power rating below its design value, often done to lower fuel consumption and emissions at the expense of peak output.

A vessel or property abandoned at sea by those in charge of it without any intention of returning.

A drying agent that absorbs moisture, used in air dryers and to protect stored equipment and spaces from humidity.

The maximum water depth at which an underwater unit, such as a submersible or diving system, is designed to operate safely.

The maximum internal pressure for which a hyperbaric (diving) chamber is designed and certified.

The duration for which a system or craft is designed to perform its intended function without replenishment or intervention.

The pressure used as the basis for designing a piping system, normally the maximum working pressure expected, with appropriate margins.

The temperature used as the basis for selecting materials and designing a piping system, reflecting the extremes the system will experience.

In chartering, the time saved in loading or discharging a ship faster than the agreed laytime, for which the shipowner may pay the charterer despatch money.

The port or place to which a ship or cargo is bound.

The removal of sulphur, either from fuel during refining or from exhaust gas by scrubbing, to reduce sulphur-oxide emissions and meet the limits of MARPOL Annex VI. IMO-grounded

The sensing of an event or condition, such as fire, gas, or a navigational target, by a detector or sensor.

An approach to subdivision and damage stability based on prescribed assumed damage extents and fixed survival requirements, as distinct from the probabilistic approach. IMO-grounded

A claw-shaped fitting used to secure the anchor chain on deck, holding it fast so the load is taken off the windlass.

The temperature at which moisture in the air begins to condense; controlling it is important in air systems and in protecting spaces and cargo from condensation.

A pressure gauge that senses pressure through the deflection of a flexible diaphragm, suitable where the process fluid must be isolated from the gauge mechanism.

An electrically insulating material, used to separate conductors and, in some fittings, to break electrical continuity and prevent galvanic corrosion.

A power arrangement that recovers waste heat from a diesel engine, for example in a steam cycle, to generate additional power and raise overall efficiency.

A compression-ignition internal-combustion engine, the dominant prime mover for ship propulsion and power generation, burning fuel injected into hot compressed air.

A propulsion system in which diesel engines drive generators that supply electric motors connected to the propellers, giving flexibility in machinery layout and load sharing.

An enhancement of satellite positioning that uses corrections from reference stations to improve accuracy, valuable for precise navigation and positioning.

A passage that slows a fluid and raises its pressure, used for example after a pump impeller or compressor to recover pressure from velocity.

A semiconductor device that allows current to flow in one direction only, used in rectifiers and electronic circuits.

Electric current that flows in one constant direction, used aboard for certain systems, batteries, and electronic equipment.

A propulsion arrangement in which the engine is connected directly to the propeller shaft without a gearbox, typical of low-speed two-stroke main engines.

A refrigeration arrangement in which the refrigerant evaporates directly in the cooling coils of the space or appliance being cooled, rather than through a secondary coolant.

A method of reducing nitrogen-oxide formation in a diesel engine by injecting water directly into the combustion chamber to lower peak temperatures.

A radio mode in which messages are received and printed directly as text, used in maritime communications such as NAVTEX and within the GMDSS. IMO-grounded

The sense in which a propeller turns, described as right- or left-handed, which affects the sideways forces during manoeuvring.

A ship unable to proceed under its own power or control because of damage or breakdown, which may require assistance or towage.

A hand-held power tool with a rotating abrasive disc, used for grinding, cleaning, and surface preparation.

The unloading of cargo from a ship; also the release of a substance such as oil, sewage, or garbage, the discharge of pollutants being regulated under MARPOL. IMO-grounded

A seafarer's personal record book documenting their sea service, certificates, and the ships served on.

Releases of substances from a ship into the sea or air; permissible discharges of oil, noxious liquids, sewage, garbage, and air pollutants are regulated by the annexes of MARPOL. IMO-grounded

An abrupt change in the geometry or material of a structure, such as an opening or a change of section, where stresses concentrate and cracks may start.

A ship security alert system that can send a covert alert ashore if the ship's security is threatened, as required under SOLAS and the ISPS Code. IMO-grounded

To leave a ship and go ashore.

The weight of water displaced by a floating ship, equal to the weight of the ship and everything aboard; the fundamental measure of a ship's size by weight.

A curve relating a ship's displacement to its draught, part of the hydrostatic data used in loading and stability work.

A pump that moves fluid by trapping a fixed volume and forcing it onward, such as a reciprocating or screw pump, as distinct from a centrifugal pump.

A vessel that is supported wholly by buoyancy and moves through the water by pushing it aside, as opposed to a planing or air-supported craft.

The volume of water displaced by the immersed hull, equal in weight to the ship's displacement.

A screen or instrument that presents information to an operator, such as a radar or electronic chart display.

Gases held in solution in a liquid, such as oxygen in boiler feed water, which may need to be removed to prevent corrosion.

Solid matter held in solution in water, the level of which is controlled in boiler and cooling water to limit scale and corrosion.

Unwanted change in the shape of a structure, such as the buckling or warping of plating caused by welding heat or by loads.

A situation in which a ship or person is threatened by grave and imminent danger and requires immediate assistance, triggering distress alerting and search-and-rescue response. IMO-grounded

An urgent signal transmitted to indicate that a ship or person is in distress and needs immediate help, sent through the GMDSS by various means. IMO-grounded

A load spread over an area or length of a structure, rather than concentrated at a point.

An unwanted change acting on a controlled system that tends to drive it away from its desired condition, which the control system must counter.

A person who works underwater, supported by diving equipment and, for deep or prolonged work, by a diving support system.

A pressurised compartment in a submersible or diving system through which divers can leave to work underwater and return, while remaining at the working pressure.

A device that redirects flow, such as a valve or guide that switches a fluid or a line from one path to another.

A pressurised chamber used to carry divers to and from the worksite at depth and to transfer them under pressure between the work area and the deck decompression chamber.

A vessel equipped to support commercial diving operations, with a diving system, decompression and saturation facilities, and usually dynamic positioning.

Tests carried out on a ship's machinery and systems while it is still at the fitting-out berth or in dock, before sea trials.

A bracket in the bottom structure that helps support and stiffen the hull when the ship rests on the keel blocks in dry dock.

A plan showing the underwater hull form and the position of internal structure, used to arrange the keel and bilge blocks for safely docking the ship.

Plugs fitted in the bottom of tanks that are removed to drain them when the ship is in dry dock and replaced before undocking.

The loads imposed on the hull when a ship is supported on blocks in dry dock, particularly before it is fully landed and supported.

The fresh water supplied aboard for drinking, cooking, washing, and other domestic use.

Closures for openings in bulkheads and the shell; watertight, weathertight, and fire-rated doors are required to maintain integrity and are regulated by SOLAS and the Load Line Convention. IMO-grounded

A coupled tug-and-barge arrangement designed to operate effectively both pushing and pulling the barge.

A ship design, used for icegoing vessels, in which the ship runs ahead in open water but turns and proceeds stern-first through heavy ice, the stern being shaped for icebreaking.

The space between the bottom shell and an inner bottom, providing protection against bottom damage and tankage for ballast, fuel, and water; double bottoms are required for many ships under SOLAS. IMO-grounded

A longitudinal girder within the double bottom that supports the inner bottom and contributes to the strength of the bottom structure.

The framing of floors and girders between the bottom shell and the inner bottom that forms the double-bottom tanks and carries bottom loads.

A deck fitting with two openings for leading mooring or towing lines.

A rescue or recovery arrangement using a double-loop line system for retrieving a person from the water.

A shaft seal using two rubber lips to retain lubricant and exclude water, as used in stern-tube and other shaft sealing arrangements.

A ferry with a bow and propulsion at each end so that it can load, sail, and discharge without turning around, used on short shuttle routes.

A shore ramp structure with two levels that allows vehicles to drive on and off two decks of a ro-ro ship simultaneously.

A structural panel with two plate faces separated by internal stiffening, giving high stiffness and a smooth surface on both sides.

An additional plate fitted over an existing one to reinforce it locally, for example around an opening or at a fitting.

The angle of heel at which water would begin to enter the hull through openings that cannot be closed weathertight, a limiting angle in damage-stability assessment. IMO-grounded

A welding position in which welding is done from above on a roughly horizontal surface, the easiest and usually fastest position; also called the flat position.

A method of determining the weight of cargo loaded or discharged by reading the ship's draughts before and after and calculating the change in displacement.

The resistance force opposing the motion of a body through a fluid; for a ship, the total of frictional, wave-making, and other resistances.

A dimensionless number expressing the drag of a body relative to its size, speed, and the fluid density, used in resistance analysis.

A load arising from drag or from a dragging action, such as that on an anchor or towed equipment.

The condition in which an anchor fails to hold and is pulled along the seabed, allowing the ship to move from its intended position.

A pipe that carries away liquid that collects in a system or space, leading it to a drain tank or overboard as appropriate.

A small hole, for example in a floor or web, that allows water to drain to the bilge so it does not collect.

A valve used to drain liquid from a tank, pipe, or piece of equipment.

The vertical distance from the waterline to the lowest point of the hull, indicating how deep the ship sits and how much water it needs to float; maximum draught is limited by the load line. IMO-grounded

An arrangement used in cable and pipe handling to control tension by drawing off and holding back the product as it is deployed or recovered.

The deliberate dragging of an anchor along the bottom, used as a manoeuvring technique to help control a ship's movement.

Moving without propulsion at the mercy of wind and current; a vessel not under command may drift.

A practised emergency exercise, such as a fire or abandon-ship drill, required at intervals under SOLAS to keep crew and passengers prepared; also a tool for boring holes. IMO-grounded

The cutting tool at the end of a drill string that bores the hole in offshore and other drilling.

Heavy thick-walled tubular sections placed near the bit in a drill string to add weight and keep the string in tension above them.

The lengths of tubular pipe that make up most of the drill string, transmitting rotation and drilling fluid to the bit.

The large-diameter pipe connecting a floating drilling unit to the wellhead on the seabed, through which the drill string passes and drilling fluid returns.

The assembled column of drill pipe, collars, and bit that transmits rotation and drilling fluid from the rig to the bottom of the hole.

A support vessel that services a drilling rig, supplying it and accommodating equipment or personnel.

A flat-bottomed, usually non-self-propelled vessel fitted with a drilling rig, used in shallow and sheltered waters.

A vessel that supports a drilling operation, carrying equipment, supplies, and sometimes accommodation alongside a platform.

A ship-shaped mobile offshore drilling unit fitted with a derrick and, usually, dynamic positioning, used to drill wells in deep water.

The system that transmits power to do work, such as a propulsion drive; also to power or operate machinery.

Unpackaged dry cargo carried loose in the holds, such as ore, coal, or grain, whose safe carriage is governed by the IMSBC Code. IMO-grounded

The sector of shipping concerned with carrying dry bulk commodities such as ore, coal, and grain.

Combustible dry waste generated aboard, which may be disposed of by incineration, the management of garbage being regulated under MARPOL Annex V. IMO-grounded

Cargo other than liquids carried in bulk or in tanks, including general, bulk, and containerised goods.

A ship designed to carry dry cargo, whether general, bulk, or containerised, as distinct from a tanker.

A fire-extinguishing agent of fine powder that interrupts combustion, used in portable extinguishers and fixed systems, including for certain dangerous cargoes. IMO-grounded

The thickness of a coating after it has dried and cured, a key measure for ensuring a coating meets its specification.

The measured thickness of a fully cured coating film, specified and checked to ensure the coating provides the intended protection.

A marine evacuation system that allows people to leave a ship into survival craft without entering the water, via a chute or slide to a platform or raft. IMO-grounded

The process by which a paint film loses solvent and hardens enough to handle, an early stage before full curing.

A drilling arrangement that allows two drilling operations to be carried out in parallel from one unit, increasing efficiency.

A passage running along the centreline within the double bottom, large enough for access, carrying piping and allowing inspection.

Fracture preceded by significant plastic deformation, absorbing energy as it occurs, in contrast to sudden brittle fracture.

The ability of a material to undergo plastic deformation before fracture, an important property for the safe behaviour of structural steel.

A passive or non-powered panel, for example a display or partition without active functions.

A ship size category representing the largest vessel able to use the port of Dunkirk, defined by that port's dimensional limits.

Material such as timber, mats, or boards placed to support, separate, and protect cargo and to keep it clear of moisture and the ship's structure.

A pair of filters arranged so that one can be in service while the other is cleaned, allowing continuous filtration without interruption.

Fine airborne particles, which in some cargoes can present a health or explosion hazard, requiring control during handling.

The engineer officer on watch or on call, responsible for the machinery during that period.

A liquid dye applied to a surface to reveal surface-breaking cracks and defects by seeping into them and being drawn out for inspection.

A non-destructive testing method using a penetrating dye to detect cracks and other defects open to the surface of a material or weld.

A load that varies with time or is applied suddenly, such as those from waves, slamming, or machinery, producing effects greater than an equivalent static load.

The automatic control of a vessel's position and heading using its thrusters and propellers, in response to position references, allowing it to hold station without anchoring.

The integrated arrangement of sensors, controllers, and thrusters that holds a vessel automatically on a set position and heading, essential for offshore and station-keeping work.

A measure of the energy needed to heel a ship to a given angle, represented by the area under the righting-arm curve, indicating its ability to absorb the heeling energy of wind and waves. IMO-grounded

A vessel fitted with a dynamic positioning system that enables it to maintain position and heading automatically using thrusters.

A craft that in operation is supported wholly or partly by forces other than buoyancy, such as hydrofoils, air-cushion vehicles, and planing craft; such craft are addressed by the IMO DSC Code and the High-Speed Craft Code. IMO-grounded