Ton

A Ton is both a measure of volume and a measure of mass or weight with two primary meanings:

A Displacement Ton (abbreviated as dTon or dT), a unit of volume is equal to between 13.5 and 14.0 cubic meters. It is derived from the volume of a ton (mass) of liquid hydrogen, the most common fuel used by starships.

A Ton (or tonne) (abbreviated as T) is a unit of mass equal to one thousand kilograms.

Additional Nomenclature

The foundation of the starship is the hull, into or onto which all other components are placed. Hulls are identified by their mass displacement (...expressed in tons; one ton equals approximately 14 cubic meters) and by their configuration.

Ships may be very large and for convenience have their masses measured in kilotons (abbreviated to Ktons), a unit equal to 1,000 standard tons. Ships of at least a megaton (or Mton), which is 1,000,000 standard tons, are rare enough that "megaton" is not commonly used. "Gigaton" (or Gton), being 1,000,000,000 standard tons, and higher units are almost unheard of when describing ships. Typically when talking about objects in space of a megaton or more (and not talking about moons, planets, stars, or larger objects), one is talking about planetoids instead of ships. These prefixes derive from the pre-spaceflight Terran International System of Units as expressed in Anglic (which also gives tera for 1,000,000,000,000, peta for 1,000,000,000,000,000, exa for 1,000,000,000,000,000,000, zetta for 1,000,000,000,000,000,000,000, and yotta for 1,000,000,000,000,000,000,000,000). Most human races have ten fingers, so most of their mathematical systems use base 10, thus their native languages have exact translations of these prefixes, which has helped drive their adoption.

In the USP, a Tonnage Code is given. This is a power of ten of the tonnage; 0 = up to 1 ton, 1 = up to 10 tons, 2 = up to 100 tons, 3 = up to 1000 tons, and so forth.

Many Kinds of Tons

Ever wondered why ship entries often have wildly different tonnage measures? Here's why:

1. Assay Ton
2. Deadweight Ton
3. Displacement Ton (dTon)
4. Dry Ton
5. Explosive Ton (Ton of TNT)
6. Freight Ton
7. Gigaton (Gton)
8. Gross Register Tonnage (GRT)
9. Gross Tonnage (GT)
10. Harbour Ton
11. Hydrogen Ton
12. Imperial Ton
13. Kiloton (Kton)
14. Long Ton
15. Longweight Ton
16. Measurement Ton
17. Megaton (Mton)
18. Metric Ton (T)
19. Net Register Tonnage (NRT)
20. Net Tonnage (NT)
21. Refrigerant Ton
22. Register Ton
23. Short Ton
24. Shortweight Ton
25. Water Ton

History & Background (Dossier)

The creation of starship deck plans is based on the assumption that one ton of mass displacement equals fourteen cubic meters. The standard displacement ton used for these calculations is derived from the volume of liquid hydrogen, the fuel source for most standard star faring vessels.

The square grid scale used on most deck plans is 1.5 meters on a side. Clearance between decks is normally 3 meters. This means that two floor squares, extended floor to ceiling, equals four 1.5 meter cubes or nearly 14 cubic meters (four lots of 1.5 m x 1.5 m x 1.5 m = 13.5 cubic meters), or one ton. A 100 dTon starship would thus contain approximately two hundred grid squares within.

Allowances of approximately + or - 10% were made in most areas to allow for better representation of specific parts of the ship and to cover various anomalies. For example, crew quarters call for four tons per sophont: the actual tonnage allocated on many plans is often less than that, but additional area is devoted to communal areas such as galley, mess, wardroom, and recreation areas.

Also, a limited volume of passages has been added to some starships. Passages and access ways which have no other use may be safely added to a ship without affecting volume or displacement for construction purposes. These additional passages should amount to no more than an additional 10% of the ship's total volume.

References & Contributors (Sources)

This article has metadata.

This page uses content from Wikipedia. The original article was at Ton. The list of authors can be seen in the page history. The text of Wikipedia is available under the Commons Attribution-ShareAlike 3.0 Unported License.

This list of sources was used by the Traveller Wiki Editorial Team and individual contributors to compose this article. Copyrighted material is used under license from Far Future Enterprises or by permission of the author. The page history lists all of the contributions.

• Marc Miller, Frank Chadwick, John Harshman. High Guard (Game Designers Workshop, 1980), 21-22.
• Marc Miller. Traders and Gunboats (Game Designers Workshop, 1980), 5.
• Jordan Weisman. "Book 2." Adventure Class Ships Volume 1 (1982): 3-4.
• Ken Pick - What is Tonnage? at Freelance Traveller