Abbreviations & Definitions
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Grain (cargo capacity) or Gram 
G or GN or GR  Grain capacity 
G-H  Ghent/Hamburg (range) 
G-H RGE  Gibraltar - Hamburg range 
G.A or GA  General Average 
G.B.  Great Britain 
G/B or GR/BL  Grain / bale capacity 
g/t-km  denotes emissions in grams per tonne of cargo shipped over a kilometre 
GA PLAN  General Arrangement Plan 
GA(P)  General agreement (plain) 
GA.CON.  General average contribution 
GA.DEP.  General average deposit 
GA/(ARB)  General average/(arbitration) 
GAL  Gallon 
gamazymes  Bioactive cleaning agents used in galleys, crew quarters and passenger sections on cruise liners 
Garbage Disposal Operations  Whereby the vessel lands a quantity of garbage for transfer to an approved garbage disposal location or facility ashore. 
Garbled  Garbling was the prohibited practice of mixing rubbish with the cargo. A distorted, mixed up message was said to be garbled. 
Gas Carrier  A specialised tanker built to comply with Marpol 73/78 Annex 1 and the appropriate IMO Code for Vessels Carrying Liquefied Gases in bulk. 
Gas Free  This refers to a steady state ‘gas free’ condition, meaning the atmosphere in the tank is “safe for man-entry”. The most common value taken for ‘gas free’ is that the atmosphere is below the LEL (Lower Explosive Limit) and that sufficient oxygen is present. Maximum allowable concentrations of any toxins must also be taken into account. 
Gas plant  Facilities, which remove liquids from natural gas streams, bear this name. So do processing units in refineries which fractionate the light ends distilled from crude or produced by cracking and other upgrading equipment. In both cases, the plant separates C3 and heavier materials from fuel gas. Some of this hardware cuts as deep as C2. Complex refineries usually have two gas plants. One, the saturates gas plant, handles paraffinic, straight run light ends. The other, the unsaturated gases plant, takes care of olefinic gas streams which come from crackers. 
Gas to C4  An abbreviation for the percent mass of the hydrocarbon gases at normal temperature and pressure from C1 to C4 inclusive, present in crude oil. 
GASBEND  Good And Safe (Port) Both ENDs 
Gasoil  An intermediate distillate product used for diesel fuel, heating fuel and sometimes as feedstock. 
Gasoil  A refined petroleum product denser than motor gasoline and kerosene but lighter than residual oil. This hydrocarbon mixture has two common uses: fuel for furnaces and for small diesel engines. It gets several popular names from these applications, including diesel and furnace oil. The phrase distillate fuel distinguishes gasoil from heavier mixtures used in large burners and large, slow diesel engines. The trade frequently shortens this term to distillate. ASTM's designation, No. 2 oil, serves as the primary name for gasoil in some parts of the world, especially North America. The refining industry employs "gasoil" To name certain intermediates in addition to familiar finished fuels. These special usages generally attach, or assume and adjective which indicates the source of the intermediate, such as atmospheric gasoil, vacuum gasoil, coker gasoil, pyrolysis gasoil, and so forth. 
Gasoline  Also called gas or petrol, gasoline is a mixture of volatile, flammable liquid hydrocarbons derived from petroleum, with or without small quantities of additives, and used as motor fuel. It is also used as a solvent for oils and fats. 
Gasoline extender  A component in motor gasoline blend added exclusively for volume. Ethanol, for example, often has this limited function in the USA. 
Gateway  Industry–related: A point at which freight moving from one territory to another is interchanged be- tween transportation lines. 
GATT  General Agreement on Tariffs and Trade 
GBB  Gross ballast bonus 
GBL  Government Bill of Lading 
GBO  Goods in bad order 
GC  Great circle 
GC or GENCAR  General cargo 
GCN  Gencon 
GCN  General cargo charter party 
GCN or GNCN or GENCON  General Conditions 
GD  Geared 
GD or GDAY or GDY  Good Day 
GD/GD  GDynia/GDansk 
GDP  Gross Domestic Product 
GDSM  General Department Store Merchandise: A classification of commodities that includes goods generally shipped by mass–merchandise companies. This commodity structure occurs only in service contracts. 
GE  Glycol Ether. Manufactured from either propylene oxide or ethylene oxide reacted with an alcohol. They are mainly used as solvents, plasticizers and brake fluids. 
GEAR  A general term for ropes, blocks, tackle and other equipment 
Geared Bulk Carriers  Typically in the handysize to handymax size range although there are a small number of geared panamax vessels, like all bulkers they feature a series of holds covered by prominent hatch covers. They have cranes, derricks or conveyors that allow them to load or discharge cargo in ports without shore-based equipment. This gives geared bulkers flexibility in the cargoes they can carry and the routes they can travel. 
Gearless Carriers  Bulkers without cranes or conveyors. These ships depend on shore-based equipment at their ports of call for loading and discharging. They range across all sizes, the larger bulk carriers (VLOCs) can only dock at the largest ports, some of these are designed with a single port-to-port trade in mind. The use of gearless bulkers avoids the costs of installing, operating, and maintaining cranes.  
GENCON  General cargo charter party 
GENCON'94  Gencon'94 charter party 
General Average Sacrifice  An extraordinary sacrifice intentionally and reasonably made to preserve from peril the property involved in a common maritime voyage. 
General Cargo  Goods unpackaged or packaged, but not shipped in bulk 
General Cargo Barge, non propelled  A barge without means of independent propulsion which carries break bulk cargoes, may be single or multi decked.  
General Cargo Barge, propelled  An self propelled barge with a single deck for the carriage of various types of dry cargo 
General Cargo Carriers  Breakbulk freighters, car carriers, cattle carriers, pallet carriers and timber carriers. A vessel designed to carry heterogeneous mark and count cargoes. 
General Cargo Ship  A single or multi deck cargo vessel for the carriage of various types of dry cargo. Single deck vessels will typically have box shaped holds. Cargo is loaded and unloaded through weather deck hatches 
General Cargo Ship (with Ro-Ro facility)  A general cargo ship with the additional capability to be loaded and unloaded by ro-ro access to a limited portion of the cargo space 
General Cargo, Inland Waterways  A vessel designed for the transportation of Break Bulk Cargoes, May Be Single Or Multi Decked. Not designed for operation in open sea. 
General Cargo/Passenger Ship  A general cargo ship with accommodation for the carriage of more than 12 passengers 
General Cargo/Passenger Ship, Inland Waterways  A vessel designed for the transportation of dry cargo and with capacity for carriage of passengers. Not designed for operation in open sea 
General Cargo/Tanker  A general cargo ship fitted with tanks for the additional carriage of liquid cargo 
General Cargo/Tanker (Container/oil/bulk - COB ship)  A general cargo ship with reversible hatch covers; one side is flush and the other is fitted with baffles for use with liquid cargoes. Containers can be carried on the hatch covers in dry cargo mode 
General Purpose Tanker  Tanker ranging in size between 10,000-24,999 DWT 
Generator Set (Gen Set)  A portable generator which can be attached to a refrigerated container to power the refrigeration unit during transit. 
Genotoxic  Capable of causing injury to the genetic component of cells. 
GENS  GENeralS or general cargo 
GENWAYBILL  General Sea Waybill 
GEO  Geographical (rotation) 
GEOG RTN or GEOG ROT  In geographical rotation 
Geometric Isomer  An isomer differing because of the structural location of certain elements. 
GEOROT  Geographical Rotation 
GES  Generic Exposure Scenarios 
GF  Government form 
GFA  Good fair average 
Ghee  A word derived from the Hindi word ""Chi"" meaning clarified and crystallised butter fat from buffalos or cows milk. Ghee made from buffalos milk is white, whereas that made from cows milk is yellow in colour. These products have a rich and pleasant flavour and have a granular structure. Granularity is considered by the consumers in some tropical countries as an important criterion of quality and purity of these products. 
GHG  Green House Gas 
GIB  Gibraltar 
GISIS  Global Integrated Shipping Information System 
Giving (someone) a Wide Berth  To anchor a ship far enough away from another ship so that they did not hit each other when they swung with the wind or tide. 
GL  General Ledger 
GL  Gearless or Germanischer Lloyd 
Glass Reinforced Plastics  See Unsaturated polyester resins 
GLESS  Gearless 
GLESS or GLS  Gearless 
Global Maritime Intelligence Integration (GMII)  It is within the Office of the Director of National Intelligence, with the mission to ensure govern- ment–wide access to maritime information and data critical to intelligence production and to serve as the focal point and oversight agent for maritime specific information issues. 
GLR  German Liner Replacement 
GLS  Gearless 
Glue Tanker  A tanker for the bulk carriage of glue 
Glyceride  An ester formed from glycerol and an organic acid 
Glycerides (Triacylgycerols)  Natural fats and oils are mixtures of triglycerides. The esters of fatty acids combined with glycerol are often referred to as "triglyceride". Typical fatty acid compositions are tabled in Appendix B. In general solid fats contain a relatively high proportion of the saturated fatty acids and oils contain higher proportions of unsaturated or shorter chain fatty acids. 
Glycerol or Glycerine  Glycerol is an important structural component of fats and oils. A complete splitting (hydrolysis) of fats/oils results in glycerol and free fatty acids. Glycerol finds uses as a humectant, a food ingredient, in pharmaceutical products and in explosives. Glycerol can be synthesised from petroleum feedstock. 
Glycol  Any of a class of organic compounds belonging to the alcohol family; in the molecule of a glycol, two hydroxyl (OH) groups are attached to different carbon atoms. The term is often applied to the simplest member of the class, ethylene glycol. See ethylene glycol and propylene glycol. 
Glyerol or Glycerine  Glycerol is an important structural compound of fats and oils. A complete splitting by hydrolysis of fats or oils results in glycerol and free fatty acids. Glycerol is used as a humectant, a food ingredient, in pharmaceutical products and in explosives. 
GM  General Manager; head of local entity 
GM  Ship Stability: Metacentric height; distance from the center of gravity to the transverse metacenter. 
GM  Gram 
GMDSS  Global Maritime Distress and Safety System (IMO) 
GMPHOM  Guide to Manufacturing & Purchasing Hoses for Offshore Moorings 
GMT  Greenwich mean time 
GN (or GR)  Grain (capacity) 
GNC  Global Navigation Chart 
GNCN or Gencon  General Conditions 
GNS  German North Sea 
GO  Gas oil 
Go–Down  In the Far East, a warehouse where goods are stored and delivered. 
GOM  Gulf of Mexico 
Gone by the Board  Anything seen to have gone overboard or spotted floating past the ship (by the board) was considered lost at sea. 
Gooseneck  The front rails of the chassis that raise above the plane of the chassis and engage in the tunnel of a container leading to the connection to tractor. 
GOP  Gross operating profit 
Gossypol  A natural constituent of cotton seeds which, if transferred to the crude oil, results in colour instability and an oil which is difficult to process. The cooking procedure of the cotton seeds is critical in determining whether gossypol is bound in the meal or transferred to the oil. 
GP  Grain capacity. Cubic capacity in 'grain' 
GP  General Purpose 
GPC  General Purposes Committee 
GPCA  Global Petrochemical Competitive Analysis.  
GPS  Global Positioning System 
GR  Grain (Capacity of vessel) 
GR  Geographical rotation. Ports in order of calling 
GR/BL  Grain/bale 
Grab Dredger  A vessel equipped to obtain material from the sea bed by use of a grab or backhoe. The material may be carried on board, transferred to other vessels, pumped ashore or deposited elsewhere using a spray 
Grab Dredger Pontoon  A non propelled dredger pontoon fitted with a system of grabs 
Grade trade  A swap of one kind of oil for another. Such business involves exchanges like sour crude for sweet and gasoil for gasoline. 
Grain Elevating Pontoon, non propelled  A non propelled pontoon used for the purpose of operating a grain elevator 
GRAINVOY  Grain charter party 
Granularity  Agglomeration of crystals resulting in the formation of granules generally visible to the naked eye. There are a number of fat-based products, such as vanaspati and ghee, where a granular structure is very much appreciated by the consumers and is considered as a quality parameter. A granular texture in fat-based products is not only determined by the chemical composition of the fat/fat blends, but also by the way the product is cooled from the melt. Generally, large granules are obtained by slow cooling of the product. Rapid cooling results in smaller crystals and smooth texture. 
Gravity  The density or weight to volume ratio of materials. The oil business usually expresses this quality in API degrees or specific gravity. 
GRD  Geared 
Green Passport  A certificate which confirms which materials have been used in a vessel’s construction 
Greenhouse gases  Greenhouse gases are those gaseous constituents of the atmosphere, both natural and antropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of infrared radiation emitted by the Earth's surface, the atmosphere and clouds. 
GRI  General rate of increase 
Gripe  A sailing vessel gripes when, by poor design or imbalance of sail, it tends to end up with its bow into the wind when sailing close-hauled. The sails flap around, forward progress is halted and she is very hard to steer. On land, the term means to complain, complain, complain. 
Groggy  In 1740, British Admiral Vernon (whose nickname was "Old Grogram" for the cloak of grogram which he wore) ordered that the sailors' daily ration of rum be diluted with water. The men called the mixture "grog". A sailor who drank too much grog was"groggy". 
Gross Registered Tonnage (GRT)  Gross Register Tonnage. Internal cubic capacity of the ship expressed in tons on the basis of 100 cubic feet per ton. This differs from DWT because it measures the volume versus the weight.

NOTE: GRT was replaced by GT back in 1982. 
Gross Terms  Terms under which the carrier has to arrange and pay for cargo handling 
Gross Tonnage  (0.2+0.02*log10V)*V, where V is the volume in cubic metres of all enclosed spaces on board 
Gross Tonnage (GT, G.T. or gt)  Gross tonnage is calculated based on "the moulded volume of all enclosed spaces of the ship" and is used to determine things such as a ship's manning regulations, safety rules, registration fees and port dues, whereas the older gross register tonnage is a measure of the volume of certain enclosed spaces.

Applies to vessels, not to cargo, (0.2+0.02 log10V) where V is the volume in cubic meters of all en- closed spaces on the vessel. Since 1994, it replaces “Gross Registered Tonnage.” An approximate conversion ratio is 1NT = 1.7GT and 1GT = 1.5DWT.

NOTE: Gross Tonnage replaced Gross Registered Tonnage back in 1982. 
Gross Weight  Entire weight of goods, packaging and freight car or container, ready for shipment. Generally, 80,000 pounds maximum container, cargo and tractor for highway transport. 
Grounding  when a vessel strikes the bottom of the sea or channel 
Groundnut Oil or Peanut Oil  The oil expressed or extracted from the seed of the groundnut ("Arachis Hypogaea") after removing the husk and the germ. Groundnuts are extensively cultivated in China, India, USA and in a number of African countries, for example Senegal, Nigeria and Sudan. The plant is unusual in pushing its unripe seed into the ground, where ripening takes place. Groundnut oil is a highly prized cooking oil. 
Groundswell  A sudden rise of water along the shore. It often happens when the weather is fine and the sea behind it appears calm. Said to occur when undulating water from a far away storm reaches the shoreline where friction causes the swell. In common use, the term groundswell means a growing change in public opinion. 
Groupage  A consolidation service, putting small shipments into containers for shipment. 
GRP  Geographic Response Plan (generally appended to ACPs) 
GRS  Geographic Response Strategies (generally appended to ACPs/GRPs) 
GSAAAAB  Good safe always afloat always accessible berth 
GSB  Good Safe Berth 
GSBAA  Good and safe berth always afloat 
GSM  Good sound merchantable 
GSP  Good Safe Port 
GSP  Government selling price. The price of crude or products established by a government marketing company. Sometimes written GEP, for government established price. See posted price. 
GSPD  Good safe port berth 
GSSL  Ports of Genoa, Savona, Spezia or Leghorn 
GSSLNCV  Ports of Genoa, Savona, Spezia, Leghorn, Naples, Civetta or Vecchia 
GSV  Gross Standard Volume 
GT, G.T. or G/T  Refers to any Gas Turbine tanker, i.e. tanker fitted with a Gas Turbine for propulsion. 
GTEE  Guarantee 
Guar  Guaranteed 
Guarantees  A seller promises to deliver oil at least as good as the guarantees--guaranteed specifications--he puts on it. When material sells on guarantees, the buyer can refuse to accept it, or demand a price adjustment, if it fails to meet any of them. 
Gunwale  The upper edge of a ship’s sides 
GVW  Gross vehicle weight 
GZ  Ship Stability: Symbol for righting arm; horizontal distance measured between the vertical lines of forces between G and B. GZ is measured horizontally from G to a point of intersection of the upward line of force from B at a point labeled Z.