Compensated gross tonnage
Encyclopedia
Compensated Gross Tonnage (CGT) is an indicator of the amount of work that is necessary to build a given ship and is calculated by multiplying the tonnage
of a ship by a coefficient, which is determined according to type and size of a particular ship.
The standard CGT system was developed in 1977 by the OECD so that inter-country shipbuilding output could be reasonably compared, as different types of ships require a greater or lesser degree of work relative to their gross tonnage
. For example, passenger ferry of a given size would require substantially more work to build than a bulk carrier
of the same size due to the differing design requirements, internal structure, and required level of detail, but simply comparing the gross tonnage or deadweight
of each ship would incorrectly show that they took the same amount of work. When expanded on a national scale, this difference could greatly mislead people as to the actual maritime production capacity of a given country.
The formula to calculate CGT was revised by the OECD in 2007.
Tonnage
Tonnage is a measure of the size or cargo carrying capacity of a ship. The term derives from the taxation paid on tuns or casks of wine, and was later used in reference to the weight of a ship's cargo; however, in modern maritime usage, "tonnage" specifically refers to a calculation of the volume...
of a ship by a coefficient, which is determined according to type and size of a particular ship.
The standard CGT system was developed in 1977 by the OECD so that inter-country shipbuilding output could be reasonably compared, as different types of ships require a greater or lesser degree of work relative to their gross tonnage
Gross tonnage
Gross tonnage is a unitless index related to a ship's overall internal volume. Gross tonnage is different from gross register tonnage...
. For example, passenger ferry of a given size would require substantially more work to build than a bulk carrier
Bulk carrier
A bulk carrier, bulk freighter, or bulker is a merchant ship specially designed to transport unpackaged bulk cargo, such as grains, coal, ore, and cement in its cargo holds. Since the first specialized bulk carrier was built in 1852, economic forces have fueled the development of these ships,...
of the same size due to the differing design requirements, internal structure, and required level of detail, but simply comparing the gross tonnage or deadweight
Deadweight tonnage
Deadweight tonnage is a measure of how much weight a ship is carrying or can safely carry. It is the sum of the weights of cargo, fuel, fresh water, ballast water, provisions, passengers, and crew...
of each ship would incorrectly show that they took the same amount of work. When expanded on a national scale, this difference could greatly mislead people as to the actual maritime production capacity of a given country.
The formula to calculate CGT was revised by the OECD in 2007.
External links
- OECD: CGT system 2007 Revision of 2007 and calculation formula