How A Ship’s Gross Tonnage Is Computated (1920)
All of us who are concerned with shipping are more or less familiar with tonnage terms, though we may not understand just how tonnage measurements are taken. This is a matter of importance, especially to those who are about to construct or otherwise acquire ships, as a clear understanding of our measurement rules will lead to a more thorough knowledge of the relation between tonnage and carrying capacity.
Net Tonnage of a Vessel and Its Computation (1920)
In a general way, net tonnage may be described as that portion of the ship's internal capacity which may be devoted to commercial uses—the carriage of passengers and freight—and is the tonnage left after certain deductions have been made from the gross tonnage.
Ship Tonnage Explained - Deadweight, Cargo, Gross, Net, Displacement (1932)
Everyone who has looked at specifications for steamships is often bewildered by the many different tonnages used for the same vessel. An ocean liner may have different gross tonnage, depending on which country's rules were used in determining the weight. Below is an article from 1932 that provides a good explanation on just what the tonnages for ships really are.
Displacement Tonnage (1913)
The displacement ton is a unit applied to vessels and not to cargo, but in order to ascertain the dead-weight tonnage a vessel can carry it is first necessary to determine the vessel's displacement tonnage.
Dead-Weight Tonnage (1913)
A vessel's dead-weight tonnage is the difference between the weight or displacement of the vessel when "light" and when loaded to its maximum authorized draft.
Net Tonnage (1913)
The rules for the measurement of vessels to determine their gross and net tonnage are not the same, and the interpretation and application of the rules are not uniform.
History of Gross and Net Tonnage Measurements (1913)
The present rules or methods followed in measuring vessels to determine their gross tonnage originated with Mr. George Moorsom, of England in the British tonnage act of 1854.
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