Old Charts: Jump Lines

Something it seems most people don’t realize about the LBB of Traveller is they were revised at least once. I have both the early and later versions and there are two differences that jump out at you.

1. The layout is better. Some headings and spacers are added and charts are gathered together.
2. The various forms from the Journal of the Traveller’s Aid Society have been added.

However, I have one difference that I honestly thought I imagined until I got my old books from my parent’s home last month.

The original LBB had a a table for determining jump routes. You compared the starport types of two worlds to their jump distance and the result was a number to roll or exceed on a D6 for their to be a jump route.

JUMP ROUTES
World Pair —-Jump Distance—-
Jump-1 Jump-2 Jump-3 Jump-4
A-A 1 2 4 5
A-B 1 3 4 5
A-C 1 4 6
A-D 1 5
A-E 2
B-B 1 3 4 6
B-C 2 4 6
B-D 3 6
B-E 4
C-C 3 6
C-D 4
C-E 4
D-D 4
D-E 5
E-E 6

Some points to note. The table is not linear on either access and only goes to jump-4 despite the tech including up to jump-6. This implies an assumed tech level that allows at least some jump-4 ships. B drives provide jump-4 on a 100 ton ship and H drives do for 400 ton ships. Drives up to H appear at tech level 10.

The chart emphasizes the importance of type A starports which automatically connect via established jump routes to adjacent starports of type-D or better and to those of type-E 83% of the time. Only C or better starports will establish jump-2 routes and even then at most half the time.

I don’t know why this was dropped from the revised LBB but I’m glad to have it back. Like any random table it might create odd results. Still, figuring out why there is a jump-1 route running a series of D and E ports for five parsecs from an A port which doesn’t even connect to an A port two parsecs away is just the creativity you want to spark.