How much is a ton of Starship?

In FGU’s Space Opera RPG (1980) Spaceships are sized in Tons. Section 9.9 in Book 2 on Page 54 tells us a ton of ship equals a volume of 3 cubic meters. 

(Or you are a true blue patriotic American fanatic, 100 cubic feet. Not equal, but close enough for D&D.)

Ships in Book 1 and Seldon’s Compendium of Space Craft Vol 1 (1981) are constant with this volume to weight ratio.

But in Seldon’s Volume 2 (1984) there’s a stealth rule change. A ton of ship is now 30 cubic meters. This ratio is repeated in Seldon’s Volume 3 (1988). We can be reasonably sure it’s not a typo.

The Nike Scout and Nemesis Corvette class ships are in both Seldon’s Volume 1 and Volume 2. In Vol1, there are volumes listed for these ships. This is consistently 3 cubic meters per ton. Volume totals are not in the stats in Seldon’s Volume 2 and 3.

I don’t believe any of FGU’s published Space Opera deck plans included a scale. They work just as well scaling 1 square meter up to 100 square feet. Triple the width and length add a few centimetres headspace and deck thickness.  A drawing scaled for  3 cubic meters equals one ton easily translates to 30 cubic meters equals one ton.

Handwave, Handwave, close enough for D&D. 

Actual weight/mass of these ships doesn’t matter. In the Space Opera game, ships use ultra-science inertia-less antigravity faster-than-light space drives. They don’t violate the laws of physics as we know them.  Space Opera sends rampaging hordes of bugs to devour the laws of physics. Space Opera tech is "Sufficiently Advanced"!

Why the change? I speculate the Nemesis corvette inspired the change. That boat carries a company of space marines. Somebody familiar with shipping requirements of a military unit may have seen the deck plans. And had a fit of the giggles. It was the 1980s, the news was full of stories about military transportation during the Gulf War.

Same for anybody who tried to fit in Fighter bays. Same for anybody who tried to figure out how some of these ships made money trading. Any ship that can’t carry standard shipping containers does not have a cargo bay. It has a broom closet.

This sort of thing was not unique to the Space Opera game. I remember it affecting the more popular Traveller Game. I was surprised while reading Traveller High Guard. A Traveller ton is 13.5 to 14 cubic meters. The volume of a ton of liquid hydrogen. Why? A ton of water is a single cubic meter. Real world ships have 3 to 5 cubic meters of interior space per displacement ton. Early deck plans published by Judge’s Guild were tiny, compared to later plans for the same ships. 


So a ton of Space Opera ship takes the volume of two tons of Traveller ship. A Nike class scout is 7.5 times the volume of a classic Traveller scout. It has a bigger crew, more and bigger guns, better defenses, and ridiculously higher performance.