Long ton
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Long ton (weight ton or imperial ton) is the name for the unit called the "ton" in the avoirdupois or Imperial system of measurements, as used in the United Kingdom and several other Commonwealth countries. It has been mostly replaced by the tonne, and in the USA by the short ton. It is equal to 2,240 pounds (1,016.0469088 kg) or 35 cubic feet (0.99108963072 m3) of salt water with a density of 1.025 g/ml.[1] It has some limited use in the USA, most commonly in measuring the displacement of ships, and was the unit prescribed for warships by international agreements between the world wars, for example battleships were limited to 35,000 long tons.
The long ton approximates the metric ton, 1,000 kg or 2,204.6226218488 lb, more closely than the "short ton", which is equal to 2,000 pounds (907.18474 kg).
Both long and short tons are defined as 20 hundredweights, but a hundredweight is 112 pounds (50.80234544 kg) in the Imperial system (long or gross hundredweight) and 100 pounds (45.359237 kg) in the U.S. system (short or net hundredweight).
The word “ton” is from the French tonne and applied to a barrel of the largest size. In Old English the spelling was tunne, meaning "cask". The volume of the antiquated British wine cask tun was defined as 256 Imperial gallons, amounting to 2,560 lb by weight.
[edit] See also
- Short ton, 2,000 lb (907.18474 kg).
- Tonnage, volume measurement used in maritime shipping. Originally based on 100 cubic feet (2.8316846592 m3).
- Tonne, also known as a metric ton (t). 1,000 kg (2,204.6226218488 lb).