G

An OCR fragment referring to G, the centre of gravity, a key point in stability whose height above the keel (KG) determines a ship's stability.

The ship's kitchen, where food is prepared; its ducts and equipment present a fire risk and attract specific fire-protection requirements. IMO-grounded

Accelerated corrosion of the less noble of two different metals when they are electrically connected in an electrolyte such as seawater, the basis of both a corrosion problem and of sacrificial cathodic protection.

The coating of steel with zinc to protect it from corrosion, the zinc acting as a sacrificial barrier.

A crane mounted on a frame that travels along rails, used for example to handle hatch covers or, ashore, containers.

A travelling gantry crane fitted to handle and stow a ship's hatch covers.

Solid wastes generated aboard ship; their handling and discharge are strictly regulated under MARPOL Annex V to prevent marine pollution. IMO-grounded

A plan required under MARPOL Annex V describing the procedures for collecting, storing, processing, and disposing of garbage aboard ship. IMO-grounded

Equipment such as compactors, incinerators, and comminuters used to treat garbage aboard ship for storage or disposal in line with MARPOL Annex V. IMO-grounded

The official log required under MARPOL Annex V in which garbage discharges and disposals are recorded. IMO-grounded

The loading, discharging, and conditioning of liquefied gas cargo, using pumps, compressors, and heat exchangers under the safety requirements of the IGC Code. IMO-grounded

The design and construction standards for ships carrying liquefied gases in bulk, set out in the IGC Code under SOLAS. IMO-grounded

The categories of liquefied-gas carrier, such as fully pressurised, semi-refrigerated, and fully refrigerated ships, distinguished by how they keep the cargo.

A ship designed to carry liquefied gases such as LNG or LPG in bulk, built to the requirements of the IGC Code. IMO-grounded

A pressure vessel holding compressed or liquefied gas, used for example for welding gases or fire-extinguishing agents.

An internal-combustion engine that burns gaseous fuel such as natural gas, used increasingly for propulsion and power to reduce emissions.

The condition of a tank or space in which flammable, toxic, and inert gases have been reduced to safe levels and sufficient oxygen is present, so it is safe for entry and hot work. IMO-grounded

The ventilation of a tank or space to remove hazardous gases and restore a safe atmosphere, carried out under controlled procedures. IMO-grounded

Instruments that measure the concentration of gases in an atmosphere, such as flammable, toxic, or oxygen content, used to check that spaces are safe.

The treatment of gas, for example to remove impurities or to liquefy or regasify it, aboard gas carriers and offshore units.

Equipment that converts a fuel such as natural gas into a hydrogen-rich gas, for example to supply fuel cells.

The conditioning of gas, such as cargo vapour or exhaust gas, to make it safe or suitable for its purpose.

An engine in which burning fuel drives a turbine directly, offering high power for low weight, used in fast craft and some naval and specialised vessels.

A space or zone where a flammable or toxic gas atmosphere may be present, requiring certified safe equipment and strict precautions, as on tankers and gas carriers. IMO-grounded

A compressible seal placed between two surfaces, such as flanges or a hatch cover and its coaming, to make the joint tight.

A light, volatile, highly flammable petroleum fuel; its low flashpoint makes it a hazardous cargo requiring stringent precautions. IMO-grounded

A valve that opens and closes by raising and lowering a flat gate across the flow, giving low resistance when fully open, used as an isolating valve.

An instrument that measures a quantity such as pressure, level, or dimension.

A transparent tube or window showing the level of liquid in a tank or boiler.

A positive-displacement pump that moves fluid using meshing gears, suited to viscous liquids such as lubricating oil.

Describing a propulsion arrangement in which the engine drives the propeller through reduction gearing to suit the propeller's optimum speed.

Describing a ship without its own cargo cranes, relying on shore equipment for loading and discharging.

A ship designed to carry packaged and break-bulk general cargo, often fitted with its own cargo gear and multiple decks.

Corrosion spread more or less evenly over a surface, causing a general loss of thickness, as opposed to localised attack.

The ship-wide alarm, required by SOLAS, of seven or more short blasts followed by one long blast, used to summon crew and passengers in an emergency. IMO-grounded

The normal lighting of spaces aboard ship, supplemented by emergency lighting that comes on if the main supply fails.

Routine, non-distress radio traffic for the operation of the ship and the business and welfare of those aboard, handled within the GMDSS. IMO-grounded

A machine that produces electrical power, normally driven by a diesel engine, turbine, or the shaft, to supply the ship's electrical system.

Relating to the physical study of the earth; geophysical survey ships investigate the seabed and sub-seabed, for example by seismic methods.

Vessels equipped to investigate the mechanical properties of the seabed and sub-seabed soils, for example by drilling and sampling for offshore engineering.

A main longitudinal or transverse structural member that supports other members and carries substantial loads.

A sealing arrangement around a moving shaft or rod, such as a pump or valve stem, that prevents leakage of fluid.

Excessive contrast or brightness that impairs vision, controlled in bridge and working areas for safety.

The processing of glass waste aboard ship by crushing it to reduce volume for storage and disposal under MARPOL Annex V. IMO-grounded

A composite of glass fibres in a resin matrix, used for small craft, boats, and components for its light weight and corrosion resistance.

A satellite navigation system providing position, velocity, and time worldwide, the primary means of position fixing on most ships.

A measure of how much a given gas contributes to global warming relative to carbon dioxide, used in assessing refrigerants and emissions. IMO-grounded

A valve with a globular body in which flow turns to pass a disc onto a seat, giving good control of flow rate, used as a regulating valve.

The metacentric height, the vertical distance between the centre of gravity and the metacentre, the basic measure of a ship's initial stability; minimum values are set by intact-stability criteria. IMO-grounded

The internationally agreed system of radio equipment and procedures, required under SOLAS, that ensures ships can send and receive distress alerts and safety information anywhere at sea. IMO-grounded

A grading term used in coating-condition assessment to describe a coating in sound condition with only minor breakdown.

The removal of metal to form a groove, for example by air-arc gouging to back-gouge a weld or remove a defect.

A device that automatically controls an engine's speed by regulating its fuel supply to match the load.

A clamshell bucket suspended from a crane, used to handle dry bulk cargo such as ore, coal, or aggregates.

A dredger that excavates the seabed using a grab bucket lowered and raised by a crane.

The loading or discharging of bulk cargo using grab buckets.

Cereal cargoes carried in bulk, which can shift and endanger stability; their carriage is regulated by the International Grain Code under SOLAS. IMO-grounded

The cubic capacity of a hold measured to the shell and including the spaces between frames, representing the volume available for free-flowing bulk cargo such as grain.

See grain capacity: the total volume of a hold available for bulk grain, measured to the inside of the shell plating.

A hatch arrangement suited to loading bulk grain.

A reference to the stowage factor of grain, the volume occupied per unit weight, used in cargo and stability calculations.

An open metal floor or walkway of bars that supports foot traffic while allowing light, air, and liquids to pass, used in machinery spaces.

An aggregate carried as a dry bulk cargo, and a material dredged and placed for seabed works.

Davits in which the survival craft is lowered by gravity once released, the boat's own weight swinging it out and lowering it, as commonly required under SOLAS. IMO-grounded

A drainage system that relies on gravity to carry liquids to a collecting point, without pumps.

A tank mounted high in the ship so that its contents can be supplied by gravity, for example a header tank for cooling water or fuel.

A semi-automatic welding device that feeds an electrode under gravity along a joint, formerly used for fillet welds in shipbuilding.

A semi-solid lubricant of oil thickened with soap, used where a clinging lubricant is needed, such as in bearings and on wires.

A device that separates grease and fat from waste water, for example from galley drains.

The ports on the North American Great Lakes, served by specially dimensioned lake vessels.

A vessel built to the particular dimensions and conditions of the Great Lakes trade, often long and of restricted beam to suit the locks.

A solid mass of water shipped aboard over the deck in heavy weather, as distinct from spray, capable of causing damage.

Gases such as carbon dioxide and methane that trap heat in the atmosphere; reducing ships' greenhouse-gas emissions is a focus of IMO measures under MARPOL Annex VI. IMO-grounded

A free-spinning vane wheel mounted behind the propeller that recovers energy from the slipstream to improve propulsive efficiency.

Lashings, often of wire or webbing, that secure a boat in its stowage against the ship's motions until it is released for launching.

Surface preparation by propelling abrasive grit or steel shot against steel to remove rust, scale, and old coatings and to create a profile for new coating.

Corrosion forming narrow grooves, often along welds or lines of stress in pipes and structure, where protective films are repeatedly broken.

Curved fins fitted to the hull ahead of the propeller to improve the flow into it and increase propulsive efficiency.

The condition of a ship resting on the seabed; also, in electrical terms, connected to earth.

The running of a ship onto the seabed or shore, whether accidental (stranding) or deliberate; a grounding may cause bottom damage and flooding.

A fitting on the sternpost into which the rudder pintle fits to form a hinge; also the gudgeon pin connecting a piston to its rod in some engines.

The upper edge of a ship's or boat's side, where the side meets the deck.

A triangular plate used to stiffen and connect structural members at a joint.

A space provided for exercise, particularly on passenger and cruise ships.

A compass that uses a fast-spinning gyroscope to indicate true north independently of the earth's magnetic field, the primary heading reference on most ships. IMO-grounded

A spinning rotor that maintains its orientation in space, used in gyrocompasses and stabilising and sensing equipment.