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.

General Average

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.

A point at which cargo is interchanged between carriers or modes of transport. A means of access, an entry.

See General Agreement On Tariffs and Trade.

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.

See General Cargo Rate and General Commodity Rate.

A general term for ropes, blocks, tackle and other equipment.

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.

Major international agreement on trade and tariffs between many nations

Intentional act or sacrifice that is carried out to safeguard vessel and cargo. When a vessel is in danger, the master has the right to sacrifice property and/ or to incur reasonable expenditure. Measures taken for the sole benefit of any particular interest are not considered general average.

There is a general average act when, and only when any extraordinary sacrifice

This shows in detail all general average costs and expenses and the contributi- on of each interest in the general average in proportion to its value.

Cargo, cosisting of goods, unpacked or packed, for example in cartons, crates, bags or bales, often palletized. General cargo can be shipped either in breakbulk or containerized. Any consignment other than a consignment containing valuable cargo and charged for transport at general cargo rates (aircargo).

The rate for the carriage of cargo other than a class rate or specific commodity rate. Synonym: General Commodity Rate.

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

See General Cargo Rate.

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.

A container used for the carriage of general cargo without any special require- ments for the transport and or the conditioning of the goods.

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.

Motor generator set as power source for e.g. thermal containers.

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.

German classification society

The procedure by which the Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection assesses the hazards of chemical substances carried in bulk by sea, producing the hazard profiles used to categorise noxious liquid substances under MARPOL Annex II. Its application was updated by resolution MEPC.344(78). IMO-grounded

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 vertical distance between a ship's centre of gravity and its metacentre, the key measure of initial transverse stability. A positive GM gives a ship a righting tendency when heeled; too small a value makes the ship tender and too large a value makes it stiff with uncomfortable rolling.

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

Grain (Capacity)

Gencon (GENERAL CONDITIONS)

The IMO framework, introduced in SOLAS regulation II-1/3-10, requiring new oil tankers and bulk carriers of 150 m and above to be designed and built to meet functional requirements ensuring adequate strength, structural integrity, and durability throughout the ship's design life, verified against defined goals. IMO-grounded

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

Common term indicating movable property, merchandise or wares. All materials which can be used to satisfy demands. Whole or part of the cargo received from the shipper, including any equipment supplied by the shipper.

International Maritime Organization (IMO) in compliance with international legal requirements.

Document issued by a competent body evidencing the quality of goods described therein, in accordance with national or international standards, or conforming to legislation in the importing country, or as specified in the contract.

A separate identifiable quantity of products or articles of a single type.

Gooseneck shaped front end of a trailer or chassis. Recess front bottom of a container to reduce the total height of the chassis plus container.

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.

Grain Capacity. Cubic capacity in ‘grain’

Geographical Rotation. Ports in order of calling.

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.

The special stability assessment required for ships carrying bulk grain, which can shift and create heeling moments as the cargo settles. The International Grain Code, mandatory under SOLAS, sets criteria limiting the assumed heeling angle and residual stability. IMO-grounded

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.

Solid water shipped on deck when waves break over the bow or bulwarks, as opposed to spray. Green water loading can damage deck fittings, hatch covers, and forecastle structures, and is a design consideration for bow strength and freeboard.

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

An indication of the position of a container in a bay plan by means of a combination of page number, column and line. The page number often represents the bay number.

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.

A manifest containing freight details without any appropriate disbursements.

Gross Registered Tonnage. The measure of the overall size of a vessel determined in accordance with the provisions of the international convention on measurement of vessels usually expressed in register ton.

A dimensionless measure of a ship's overall internal volume, calculated by a formula in the International Convention on Tonnage Measurement of Ships, 1969. It is widely used to determine the applicability of regulations, manning scales, and various fees and dues. IMO-grounded

Weight (mass) of goods including packing, but excluding the carrier’s equip- ment expressed in whole kilograms. The weight of a shipment including materials necessary for blocking etc.

Total weight of container including cargo (in kilograms).

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.

The collection of several small consignments and the formation of one large shipment thereof (road cargo).

A location where groupage takes place (road cargo). One who consolidates LCL consignments to offer to a carrier as an FCL.

Gross Registered Tonnage

Good, Safe Berth

Good, Safe Port

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.