[T:IW/SS] Traveller dTon to SS tonnage?
 

Is there a formula - official or otherwise - to turn a "displacement ton (dton)" as used in Traveller: Interstellar Wars into a regular "ton" as used in the Spaceships line?

I started thinking about how much more detailed the T:IW system can be for "in-between" sizes (e.g. 20 tons, 50 tons, 75 tons, 200 tons, 500 tons, etc.) and started looking at my T:IW book, and then I realized that the dTon is not the same as a ton. So, some help?

Re: [T:IW/SS] Traveller dTon to SS tonnage?
 

There's no real conversion, as dTon is really a measure of volume while the Spaceships rules revolve entirely around the ships mass. The best conversion I've done is to just use a rough approximation of the ships Loaded Mass from Traveller (LMass) as the basis of the ships mass in the Spaceships design system, then set SM accordingly based on the Hull Size Table on Spaceships p. 9.

RPK has rules for using GURPS Spaceships in Traveller.

I have some very rough guidelines for intermediate SM ships in GURPS Spaceships, as well as implementation of those rules and RPK's rules in my GURPS Spaceships Design Spreadsheet.

Using those I've designed 100dTon versions of the Suliman as being SM+7 and 300 tons mass while the 200dTon Beowulf and Empress Marava are SM+7.5 and 600 tons mass.

Re: [T:IW/SS] Traveller dTon to SS tonnage?
 

It can't be done, because dtons are a measure of volume and tons are a measure of mass. One dton is one ton of hydrogen fuel tanks, probably about the same for living quarters, more like 5 tons of cargo space or machinery, and an essentially meaningless amount of armor (hundreds of tons).

Re: [T:IW/SS] Traveller dTon to SS tonnage?
 

I can never get that spreadsheet to work in OpenOffice; I've stopped trying. :(

It still seems people are looking at things a little backwards from what I want, though. I want to make the ship in T:IW while shooting for a set tonnage (and relevant SM) rather than using SS, but folks seem to think I want to make the ship in SS. SS is a bit too limited for what I want.

Eric, I'll look at those rules later. :)

Re: [T:IW/SS] Traveller dTon to SS tonnage?
 

If you want to make the ship in IW then do it however it makes sense there. Add up all the things you want on the ship and that will lead you to a size. If you want a particular size then adjust your want list but you're not going to be able to make IW ships come in neat 1/20th of the ship's mass modules.

Re: [T:IW/SS] Traveller dTon to SS tonnage?
 

A Traveler ship's LMass is it's weight, or at least I'm pretty sure it is, you can probably get away with converting that straight into tons for SS

Re: [T:IW/SS] Traveller dTon to SS tonnage?
 

There have been quite a few rule systems for designing Traveler Starships since the original High Guard rules which is pretty much what canonized the dton as a unit of measure (along with the original Traveler rules) and a lot of them also calculated the ships mass along with the volume. I've fiddled with a lot of them and even created a homebrew or two and I'd found that the ships mass usually averaged out to about 3 - 4 tons of mass per dton.