Coming back to this:
For tech levels I use:
Code:
Trav TL GURPS TL
0 0
1 1
1 2
1 3
2 4
3 5
4 6
5 6
6 7
7 7
8 8
9 9
10 (A) 9
11 (B) 9
12 (C) 10
13 (D) 10
14 (E) 11
15 (F) 11
16 (G) 11
17+ 12
For spaceship design I use
GURPS Spaceships, and so have a few house rules to get a better fit. The primary one is for jump drives and fuel. I have jump drives take one system, regardless of rating. They cost as a standard hyperdrive times (jump rating + 1)/2 (though that might be too cheap, and twice or even five times this might fit Traveller better). A J-drive requires either its rating in power-points for a full 10 minute turn, or half that for two 10-minute turns.
The fuel requirement is jump distance in systems. This might seem low, but
Spaceships assumes a lot of systems are eaten up in stuff that takes up little space in a CT ship, so it works out fairly well.
As you'd expect from the above TL table, TL9 limits you to J1-2, TL10 to J3-4, and TL11 allows J5-6.
As a matter of campaign feel, I use the electro-mechanical computer option, which means that TL10 computers are only about as capable as ours today.
As a rule of thumb, the mass of a ship for Spaceships can be taken from" Traveller Displacement Tons x 4 to 4.5, round to nearest standard SM/mass. Round in whichever direction seems to make the most sense. Most small craft are 100 tons, a Shuttle or a Type-S scout is 300 tons, 200-300 ton traders are 1000 tons, a 400 ton subbie or a 600t ton liner are 3000 tons, as is a Broadsword. It's pretty coarse, but it's been working for me.