GURPS Spaceships Series

[David L Pulver]

Originally Posted by ericbsmith

All good news, though that pretty much wraps up the current plans for the Spaceships series. Might I humbly suggest a GURPS Spaceships 9: Traveller? Covering both the Interstellar Wars and GURPS 3e Eras would be nice.

A formal, official SPACESHIPS book would be a tricky conversion, though: since every +2 SM is a 10 fold mass (and presumably volume) increase, it's hard to maintain some of the canonical relationships of ship classes. E.g., 400, 600, 800, and 1000 d-ton ships would blur together. This is an issue because the ships have 30+ years of familiarity and people are attached to them (and they're often depicted in extent deck plans) and many adventures and economic edifices have apparently been constructed around their precise sizes and exact costs. On a less formal level, I did do a JTAS article suggesting rule-of-thumb conversions, and others have also taken a stab at it.

It *would* be possible to get much closer using the same system but with a somewhat finer grain of hull sizes, but that would be incompatible with the existing series, though it might make a fine system for a dedicated Traveller revision.

[dataweaver]

Originally Posted by David L Pulver

It *would* be possible to get much closer using the same system but with a somewhat finer grain of hull sizes, but that would be incompatible with the existing series, though it might make a fine system for a dedicated Traveller revision.

Actually, I hammered out some rules at one point for extending the current Spaceships rules to allow for finer granularity; they work rather well, and are fully compatible with the current system*. My goal at the time was aimed at allowing the creation of a wider variety of mecha, not just 10-ton, 30-ton, and 100-ton designs; but I don't see why you couldn't apply the same concept to larger ships - and a Spaceships X: Traveller designs supplement would be a perfect excuse to publish them.

In fact, doing this would be much easier; for the Mecha-related stuff, I put in a tweak to the "roughly box-shaped hull" assumption of the Spaceships design system so as to better allow for more bizarre shapes (such as humanoid hulls, with systems in the limbs as well as the body). That tweak, and the issues that go along with it, wouldn't be needed for a Traveller-based supplement.

The core mechanism isn't too different from the way that Spaceships 4 extended the design range down to SM +4, except that it interpolates between existing entries rather than extrapolating from the end. The secret is to allow decimal SM adjustments, in steps of 0.2 rather than 1 - and to apply these intermediate steps to systems as well as the hull. With this revision, hull sizes between SM +6 and SM +8 allow for 100 tons, 125 tons, 150 tons, 200 tons, 250 tons, 300 tons, 400 tons, 500 tons, 600 tons, 800 tons, and 1000 tons, not just 100, 300, and 1000 tons. If you need more granularity than that, I could revise the decimal adjustments to allow for SM increments of 0.1, which would bring 700- and 900-ton hulls into the fold, and would result in hull sizes being able to vary by roughly 10% in mass, as opposed to the current three-fold granularity.

* - well, not quite fully compatible; but the handful of incompatibilities had nothing to do with improving the granularity of the system. They dealt more with the allowance for subassemblies and an option for variable system sizes - both matters about which a Traveller supplement wouldn't need to worry.

s

[Langy]

I made a post a bit back that has all the formulas for deriving statistics and prices for each system (including conventional guns and missiles, though I don't remember if I did energy weapons or not) given any arbitrary ship size. I back-calculated them, so they might not all be perfect, but if not they're still pretty close.