In which case you still can't get J6 until TL10, unless it also lacks the drive limits by TL in bk 3, as the JDC is 20, the bridge is 20, and the JFuel is 60, on a 100Td, and a D drive max won't get past rating 4 on a 200T nor rating 1 on a 400T hull. But you can get it on a 200T at TL10.
But then, a '77 era ship can have a PP less than the JD... just not less than the MD, too...
And a Model 1 can only hit J2 under B2'77... due to the program space
A 1bis can hit J4 under B2'77. A model 2 can hit J3, and a 2bis j6.
'77 version TL 10 J6
200 hull
020 Bridge
002 mod/2bis
004 SR x1
001 MD A=1
004 PP A=1
035 JD F=6
120 F 1j6
010 F p1
004 Cargo
Given TL9=A-D TL10=E-H TL11=J-K, TL12=L-N TL13=P-Q, TL14=R-U
In point of fact, you can't get J6 under B2'81 until TL12 due to drive limits... as well as computer limits. The 200 Tonner can't fit; P6+J6 fuel = 60+120=180... that leaves only the bridge and no drives. Even chopping fuel, once we add the 54Td drives, we got no fuel space left to make it a week.
The 400 Tonner needs a drive M to do rating 6.
minimum J6 ship Bk2'81 - TL12
400 Hull
020 Bridge
002 Mod/2bis
008 SRx2 (minimum crew is 3...)
065 JD M=6
003 MD B=1
037 PP M=6
240 JFuel 1j6
025 PFuel 11d 16h
000 Cargo
That's a pretty useless port-to-port courier-only. So useful Bk2'81 J6 is 600Td drive T, and even then, you cut back fuel to have cargo, turrets, and crew space. (but by dropping to 25T PP fuel, it can have 35T for the minimum 5 crew and some cargo... and up to 6 turrets. It's your light-fast-ship.
