CT Only: Jump Torpedoes

[mike wightman]

The express boat system uses jump 4 xboats for every designated link - even the jump 1 links.
This is OTU canon.

The xboat jumps within a few hours at a time, each message travels one jump pre week, so if you send a message today it will arrive in a week. Send a message tomorrow and it will arrive in a week. Take both of those bits of CT canon and you reach the inescapable conclusion that xboats must leave at least once per day on every route the current world has a link to, sometimes more often (a few hours turn around time for the boat is canonical).

 

[Condottiere]

It's modelled on the Poni Express.

 

[Proneutron]

The express boat system uses jump 4 xboats for every designated link - even the jump 1 links.
This is OTU canon.

Do you recall where this was covered? I can't for the life of me remember. I do remember something about from 40+ years ago.

 

[mike wightman]

Library data A-M, Library Data N-Z, Traders and Gunboats are the primary sources, then there is the JTAS article on the IISS and LBB:6, and finally The Traveller Adventure.

 

[Grav_Moped]

Getting back to the mechanics of a j-torp...

The (non)canon j-torp is essentially a jump drive, fuel tank, and a tape recorder connected to a radio transmitter.
The launching ship will need to have a computer that can run Generate, Navigate, and Jump-n to set the j-torp's course.
This requires CPU space = 2+Jn (in all except LBB2'77, it would also require a computer Mod/n=Jn, but this only works in '77 so it's a moot point).
One-shot guidance-programming tapes (like Jump Tapes but incorporating Generate, Navigate, and Jump-n) are available for Cr10000/Jn+Cr2000 [not sure of pricing]
(This only works in a universe where all parameters of Jump, including drive control inputs, are determined just prior to Jump.)

In LBB2:'77 the minimum size possible is 11.2TD at MCr10 and a bit (based on using a Size A drive, fuel-limited to J1).
J6 would have to be 25Td, of which 15Td would be fuel.
You're stuck with LBB2 since both versions of High Guard require power plants for jump drives and this thing doesn't have one.

But, using the formula underlying the Drive Performance Table, you can work out drives smaller than Size A.
The formula is Jump Drive tons = (0.025*hull tons*Jn)+5
Cost is MCr0.05*M*Jn -- yes, the cost is by ship tonnage and Jn, not per ton of drive!
This makes short-range j-torps under this system insanely cheap, which is really going to mess up the game universe.

(Non-)canon J-Torps:
              Tons  Tons 
Jn Tons  MCr  Fuel  Drive  
1   6    0.3  0.85  5.15 
2   7    0.7  1.65  5.35
3   8    1.2  2.4   5.6
4  10    2.0  4.0   6.0
5  13.5  3.4  6.8   6.7
6  20    6.0  12.0  8.0

Ok, let's invoke drop tanks for J6:
Now it's only 6Td (the 5.9Td jump drive is just jumping itself plus 0.1Td of electronics or whatever, no fuel or power plant).
The drive costs MCr1.8.
The drop tank needs to supply 9 tons of fuel.
This fuel could come from the launching ship's tankage but the ship will need to be able to get itself 100D away from the j-torp before it jumps.

But this can't be rules-compliant even if you handwave the computer...
It only works under LBB2:'77, but it can't work without drop tanks.
If you use drop tanks, you're acknowledging that LBB5:'79 (if not '80) exists and applies.
But LBB5 says it needs a power plant and 4 weeks of fuel.
Oops.

 

[Proneutron]

Library data A-M, Library Data N-Z, Traders and Gunboats are the primary sources, then there is the JTAS article on the IISS and LBB:6, and finally The Traveller Adventure.

Thanks!!

 

[Grav_Moped]

Cleaned up the LBB2:'77 Jump Torpedo analysis a bit.

Holy crap are the short-range ones cheap!

(It's because the jump drive cost formula is based on ship tonnage and jump number, rather than per ton of drive.)

I don't like these results from a worldbuilding and game balance perspective.