Originally posted by Pale Horseman:
It would appear the Jump fuel allocations for the Standard designs do not follow the rules in the design chapter. A 400 ton vessel with a Jump 2 drive requires 12 Jump units which each require 10 tons of dedicated jump fuel. Both 400 ton J2 ships (the corsair & lab ship) only have 80 tons. This would match the text in the Design chapter (10% of the ships volume x Jump number) while contradicting the actually drive unit descriptions.
Are they trying to confuse us to death or what?
You're confusing drive units and tons of drive. Not hard, given they way it's written, but let's see if we can't clarify things.
Per p.259, a 400-ton hull requires 8 drive units, regardless of the specific type or capacity of drive installed.
Per p.265, Jump 2 drive units each displace 1.5 tons and require 10 tons of fuel. Note that this fuel requirement is per drive unit, not per ton of drive.
Thus, a 400 ton ship requires 12 tons of Jump drive (8 units x 1.5 tons/unit) and 80 tons of jump fuel (8 units x 10 tons/unit).
Clear?
In case you're wondering, these "drive units" are obscuring (IMO) a very simple mathematical relationship. Jump drives require (Jump number+ 1) percent of the ship's total displacement (Jump-1=2%, Jump-2=3%, Jump-3=4%, etc.). They also require ten percent of the ship's displacement per jump number (J-1=10% fuel, J-2=20% fuel, etc.)
For Maneuver drives, the formula is (Acceleration*3)-1 percent. (1g=2%, 2g=5%, 3g=8%, etc.)
These formulas are much easier to use than the drive units approach, IMO. I wish they had been included explicitly in the design sequences for people who prefer to solve formulas instead of stacking blocks.
