Long ton

Last updated
Long ton
Unit system Imperial units, U.S. customary units
Unit ofMass
In base units2,240 lb
Conversions
1 in ...... is equal to ...
   SI base units   1,016.047 kg
   Metric tons   1.016047 t
   Short tons   1.12 short tons (exactly)

Long ton, [1] also known as the imperial ton or displacement ton, [1] [2] is the name for the unit called the "ton" in the avoirdupois system of weights or Imperial system of measurements. It was standardised in the thirteenth century. It is used in the United Kingdom and several other Commonwealth of Nations countries alongside the mass-based metric tonne defined in 1799, as well as in the United States for bulk commodities.[ citation needed ]

Contents

It is not to be confused with the short ton, a unit of weight equal to 2,000 pounds (907.18474  kg ) used in the United States, and in Canada before metrication, also referred to simply as a "ton".

Unit definition

A long ton is defined as exactly 2,240 pounds. The long ton arises from the traditional British measurement system: A long ton is 20 hundredweight (cwt), each of which is 8 stone (1 stone = 14 pounds). Thus a long ton is 20 × 8 × 14 lb = 2,240 lb.

Unit equivalences

A long ton, also called the weight ton (W/T), [1] imperial ton, or displacement ton, is equal to:

The long ton remains in use in both the United Kingdom and the United States, where it is commonly used in measuring the displacement of ships, the volume-to-carrying-weight of fuels, and in trade of baled commodities [1] and bulk goods like iron ore and elemental sulfur. The long ton was the unit prescribed for warships by the Washington Naval Treaty of 1922—for example battleships were limited to a displacement of 35,000 long tons (36,000 t; 39,000 short tons).

To comply with the practices of the European Union, the British Imperial ton was explicitly excluded from use for trade by the United Kingdom's Weights and Measures Act of 1985. [3] [4]

The long ton remains in informal use by some heritage rail companies and remains on a limited number of weight limit signs on roads (usually in remote areas away from major towns and cities where tonnes are used).[ citation needed ]

See also

Related Research Articles

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Ton Unit of mass or volume with different values

The ton is a unit of measure. It has a long history and has acquired a number of meanings and uses over the years. It is used principally as a unit of weight. Its original use as a measurement of volume has continued in the capacity of cargo ships and in terms such as the freight ton. Recent specialized uses include the ton as a measure of energy and for truck classification. It is also a colloquial term, "ton" is the heaviest unit of weight typically used in colloquial speech. It is also used informally to mean a large amount of something, material or not.

Tonne Metric unit of mass equivalent to 1,000 kilograms

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United States customary units System of units of measurement commonly used in the United States

United States customary units are a system of measurements commonly used in the United States since it was formalized in 1832. The United States customary system developed from English units which were in use in the British Empire before the U.S. became an independent country. The United Kingdom's system of measures was overhauled in 1824 to create the imperial system, which was officially adopted in 1826, changing the definitions of some of its units. Subsequently, while many U.S. units are essentially similar to their imperial counterparts, there are significant differences between the systems.

Avoirdupois system System of weights based on a pound of 16 ounces

The avoirdupois system is a measurement system of weights that uses pounds and ounces as units. It was first commonly used in the 13th century AD and was updated in 1959.

Tonnage is a measure of the cargo-carrying capacity of a ship, and is commonly used to assess fees on commercial shipping. The term derives from the taxation paid on tuns or casks of wine. In modern maritime usage, "tonnage" specifically refers to a calculation of the volume or cargo volume of a ship. Although tonnage (volume) should not be confused with displacement, the long ton of 2240 lb is derived from the fact that a "tun" of wine typically weighed that much.

Twenty-foot equivalent unit Unit of cargo capacity, TEU

The twenty-foot equivalent unit is an inexact unit of cargo capacity, often used for container ships and container ports. It is based on the volume of a 20-foot-long (6.1 m) intermodal container, a standard-sized metal box which can be easily transferred between different modes of transportation, such as ships, trains, and trucks.

Bushel

A bushel is an imperial and US customary unit of volume based upon an earlier measure of dry capacity. The old bushel is equal to 2 kennings (obsolete), 4 pecks, or 8 dry gallons, and was used mostly for agricultural products, such as wheat. In modern usage, the volume is nominal, with bushels denoting a mass defined differently for each commodity.

Hundredweight Unit of weight or mass, with differing values

The hundredweight, formerly also known as the centum weight or quintal, is a British imperial and US customary unit of weight or mass. Its value differs between the US and British imperial systems. The two values are distinguished in American English as the "short" and "long" hundredweight and in British English as the "cental" and the "imperial hundredweight".

The short ton is a mass measurement unit equal to 2,000 pound (lb). It is commonly used in the United States, where it is known as simply a common ton.

Deadweight tonnage measure of how much weight a ship can carry

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English units are the units of measurement used in England up to 1826, which evolved as a combination of the Anglo-Saxon and Roman systems of units. Various standards have applied to English units at different times, in different places, and for different applications.

History of measurement Aspect of history

The earliest recorded systems of weights and measures originate in the 3rd or 4th millennium BC. Even the very earliest civilizations needed measurement for purposes of agriculture, construction and trade. Early standard units might only have applied to a single community or small region, with every area developing its own standards for lengths, areas, volumes and masses. Often such systems were closely tied to one field of use, so that volume measures used, for example, for dry grains were unrelated to those for liquids, with neither bearing any particular relationship to units of length used for measuring cloth or land. With development of manufacturing technologies, and the growing importance of trade between communities and ultimately across the Earth, standardized weights and measures became critical. Starting in the 18th century, modernized, simplified and uniform systems of weights and measures were developed, with the fundamental units defined by ever more precise methods in the science of metrology. The discovery and application of electricity was one factor motivating the development of standardized internationally applicable units.

Comparison of the imperial and US customary measurement systems

Both the British Imperial and United States customary systems of measurement derive from earlier English systems used in the Middle Ages, that were the result of a combination of the local Anglo-Saxon units inherited from Germanic tribes and Roman units brought by William the Conqueror after the Norman Conquest of England in 1066.

Builder's Old Measurement is the method used in England from approximately 1650 to 1849 for calculating the cargo capacity of a ship. It is a volumetric measurement of cubic capacity. It estimated the tonnage of a ship based on length and maximum beam. It is expressed in "tons burden", and abbreviated "tons bm".

The units of transportation measurement describes the unit of measurement used to measure the quantity and traffic of transportation used in transportation statistics, planning, and their related fields.

Displacement (ship) Ships weight

The displacement or displacement tonnage of a ship is its weight. As the term indicates, it is measured indirectly, using Archimedes' principle, by first calculating the volume of water displaced by the ship, then converting that value into weight. Traditionally, various measurement rules have been in use, giving various measures in long tons. Today, metric tonnes are more commonly used.

Ship measurements consist of a multitude of terms and definitions specifically related to ships and measuring or defining their characteristics.

Imperial and US customary measurement systems

The imperial and US customary measurement systems are both derived from an earlier English system of measurement which in turn can be traced back to Ancient Roman units of measurement, and Carolingian and Saxon units of measure.

The sack was an English unit of weight or mass used for coal and wool. It has also been used for other commodities by weight, commodities by volume, and for both weight and volume in the United States.

References

  1. 1 2 3 4 5 "Definitions, Tonnages and Equivalents". Military Sealift Fleet Support Command Ships. Archived from the original on 24 July 2017. Retrieved 11 September 2016.
  2. 1 2 Dictionary.com - "a unit for measuring the displacement of a vessel, equal to a long ton of 2240 pounds (1016 kg) or 35 cu. ft. (1 cu. m) of seawater."
  3. legislation.gov.uk: Weights and Measures Act 1985 Retrieved 17 January 2013.
  4. A Dictionary of Weights, Measures, and Units, edited by Donald Fenna, Oxford University Press