Originally posted by far-trader:
Perusing Book 2 I stumbled across its canonical answer to this question. 1d6 days (pg. 6 "Drive Failure").
Ah, you beat me to the punch.
But as to the overall logistics...
I'm a little confused about the original fuel profile.
As per canon, a Type A2 is a 200-dton Jump-2 vessel, and typically (B2, 2e) needs only 60 dtons of fuel: 40 dtons of Jump fuel (20% of 200) and 20 Powerplant fuel (Powerplant-2 times 10 dtons).
What's being described (maybe from a thread last week which I missed?) is more like a Solomani Type SA, a 400-dton Jump-2 merchant. That vessel requires a base 100 dtons of fuel: 20% times 400 equals 80, plus 10 dtons times Powerplant-2. Looks like they're carrying 20 dtons more fuel than they typically need. (I am
assuming M-2 and P-2 here, since a B2 "merchantman" whose M-drive rating exceeds her J-drive rating is not a "merchantman" but rather some sort of "yacht" or "gunboat", as I can guarantee she won't meet expenses doing honest haulage no matter how one "adjusts" the trade/speculation system.)
Normally, they hop 2 pscs and burn 80 dtons of Jump fuel, plus (approximately, if one insists on that dorky 168 hours ± 10% Jump duration nonsense) 5 dtons for the Powerplant (one-fourth of 20 dtons), leaving (again, "approximately"
) 15 (three weeks' worth) in the tanks. But for whatever reason, this version has an extra 20 onboard, bringing the leftover total to 35-ish (which is around seven weeks' worth, incidentally).
35 dtons still isn't enough for an escape (even Jump-0 to the other side of the system takes a minimum 10%, meaning 40 dtons), but it might have been possible to plan ahead. To whit: is the vessel (again, from the examples of the Type SA and Type R) carrying a standard 20-dton Launch, fitted as a Lifeboat, perhaps? If player-characters have been trained to the proper level of paranoia appropriate to a "hard science fiction" setting, they'd have long ago fitted it with a modest-sized collapsing tank for just such an emergency, and would be in the habit of keeping it topped off for a rainy day.
Then they could simply pump all however many spare dtons of fuel they managed to bring with them aboard the Launch into the starship's tanks (before they leave Jumpspace, rather than in combat, I should think). As long as they have at least 5 dtons (the rest of the Launch being emer low berths and whatnot), they can top up the starship to 40.
So that solves the Jump fuel problem.
What to do about Powerplant (and thus life supp)?
Two options. On the one hand, they can pile into the Lifeboat, fire it up but not launch it, and pack crew and pasengers (except maybe the regular Lows, who'll be fine where they are since low berths operate on internal power appearantly) into the emer lows as either couches or proper low for the week in Jump (Fast Drug can make the time in a couch pass quicker), then just let the mothership sputter and go cold while in Jump. This requires the (reasonable?) assumption that Powerplants are not required to maintain Jump once its initiated, but normally run during Jump only to provide power to all the
other ship systems. Upon breakout, they temporarily abandon the mothership (no, it's not then available for salavage; see other threads on that topic) and go look for help (or at least more fuel).
On the other hand, if they have enough extra fuel stashed away, 10 dtons or so, they can put a total of 45 into the starship, and make a Jump-1 (or less) escape outta there as "normal"... and, as expected, they'll be "running on vapors" upon the next breakout, so there's probably a sortie aboard the Launch to look forward to at that point.
IMTU, I build my Type SAs with 100 dtons of fuel, no default small craft, and a 180-dton hold (6 Cutter Modules equivalent). I then stick a 30-dton collapsing tank in there for the aforementioned rainy day. On less-than-full-freight runs, with 130 dtons of fuel total, she's got what she needs for an emergency Jump-1 after a routine Jump-2.
The only other issue I have is that if the characters deplete the batteries after 1D6 days, what do they then use to restart the fusion reaction in the Powerplant? Presumably they can, somehow... but it's unclear where they gets the joules...
