The TL limits are in CT LBB 3 1977 pages 10-11 and CT LBB 3 1977, 1981 pages 14-15. CT LBB 2 1977, 1981 page 82 has TL limits for computers.

CT LBB 3 1977, 1981 page 15 has CT LBB 2 1977, 1981 page 22 Drive Types A through D available at TL 9. A 100 ton hull's jump drive type C can do a six parsec jump. Referring back to CT LBB 2 1977, 1981 page 14 "...For example, a ship must have a Model/4 computer before it ca perform jump-4, in addition to the proper size jump drive." In the notes below the Computers Table on CT LBB 2 1977, 1981 page 22 is this sentence "Model also affects jump ability." The Computer Table shows that a Model/6 computer is available at TL 12 which means the six parsec Jump Drive C is not available until TL 12.

On October 6, 2019 at 12:17 PM Cian Witherspoon <xxxxxx@gmail.com> wrote:

Looking at the LBB gives an interesting perspective, since the “standard” drives in there don’t have a TL limit on potential (just a cap of J6), but do have one on drive size. This means that you can take the highest potential JN and multiply it by that hull size/100 to create a “real potential range” number for that particular drive model (or just divide tonnage by 100 and multiply by jump number if you’re doing this for individual ships), and then divide that by the actual hull size you’re installing the drive in to get that configurations jump number.

You can also do this for M-drives, to get tons of thrust for a drive model.

High Guard introduced “Jump potential by TL”, but it sort of implies, in the context of HG vs LBB2, that this applies only to custom military jump drives.

Looking at Tom’s example, j4 for 400 tons would be potential 16, and when installed in a 300 ton hull would give J5.33.