Fuel Fittings: Cost and volume

[Midgardsormr]

The fuel fittings chart lists costs per ton, but it isn't clear on exactly what tons we're talking about: Tons of fitting? Tons of ship? Tons of fuel tankage?

As written, it makes the most sense to think that it's per tons of fitting since there is no volume column in the chart, and the pumping rate is given as a constant. That really makes the fittings really efficient, though, and I can't imagine designing any ship without at least a ton of refinery aboard, and scoops are almost equally a no-brainer.

A lot of hexes that would otherwise be risky for a small civilian ship to enter become accessible at a cost of only two tons of cargo and a bit of time.

Thoughts? Am I misreading the rules?

 

[robject]

Nope, you're right, it's cost per fitting.

And, I don't know if they're too efficient or not. Were you comparing numbers with a different version of the rules? For example, if you were comparing them with Mongoose, then I imagine that could be phrased in terms of errata, e.g.:

The fuel refinery appears far too efficient... every ship can have one. It would seem more accurate to the Traveller universe to increase its unit tonnage to 5(?) tons and its refining capability to XX tons per hour per unit.

 

[Midgardsormr]

And, I don't know if they're too efficient or not. Were you comparing numbers with a different version of the rules?

No, I've only got CT to compare to, and I don't recall the component being listed in Book 2. Come to think of it, I don't remember exactly what made the difference in drives that could use unrefined fuel. I'll have to go back and look for that.

The observation was based merely on my experience running games with very conservative players who wouldn't risk entering developing hexes with their Free Trader out of fear of not having access to refined fuel.

They'd gladly give up two tons of cargo space for scoops and refinery, but I'll bet they'd think about it a little harder if it were 5 or 10 tons instead.

I'll have to give it some thought before I decide whether or not to house rule it. There are different adventuring possibilities either way; I just have to decide which one is better for my games.

 

[Major B]

Come to think of it, I don't remember exactly what made the difference in drives that could use unrefined fuel. I'll have to go back and look for that.

You just reminded me of an unanswered question of mine. I've always thought that jump drives need refined fuel or they run the risk of misjump. Power plants do not have to worry about that.

Is this still true with T5?

 

[Midgardsormr]

Alright, I finally went back to CT to check on the unrefined fuel issue. Book 2 simply states that a ship using unrefined fuel "(and not equipped to do so)" adds +1 to the drive failure roll and +1 to the misjump roll. There is no detail about how to equip a drive to use unrefined fuel, but it does say that military and quasi-military ships are so equipped. Oh, and the drive failure roll is made for all drives, power plant included. If it fails, then another roll is made for each system to determine which, if any, of them fail.

Book 5 — High Guard gives a Fuel Purification table indicating the tonnage and price of purification at various tech levels, based on a fuel capacity of 1000 tons. Ships with smaller fuel requirements may use proportionally smaller refineries, but "In no case may a fuel purification plant be procured with less than one-fifth the tonnage and price shown." No information is given about how long it takes such a refinery to convert the fuel.

So supposing a Type A Free Trader constructed at a Tech Level 12 shipyard, an appropriate refinery would be at the minimum available size of 6 tons. The smallest possible refinery in the list is TL 15 and 3 tons.

As to a rule governing the use of unrefined fuel in T5, I haven't run across it yet. It's nowhere in the design rules or the How Things Work chapters, and it's not in the Engineer skill description.

 

[Reban]

I've always thought that jump drives need refined fuel or they run the risk of misjump. Power plants do not have to worry about that.

Actually.....from the How Power Plants Work chapter its not clear but could be interpreted as refined or unrefiened hydrogen can be used in fusion plants.

In the Fuel Benchmarks chapter on p.360 it says:

"The gathering equipment includes appropriate filters, catalysts,
and treatments to make the fuel usable in the power plant." in relation to atmospheric hydrogen, ice and water.

And "Pure (or refined) fuel, properly filtered and certified for power plant use, if available for Cr500 per ton with local personnel doing the fuelling."

That suggests to me 1). Refined fuel is needed (or at least favored) for fusion PPLants and 2). Fitting a Fuel Purifier is a must.

Weirdly I can't see anything about unrefined fuel causing a misjump in the unplanned outcomes chart on p.373

 

[Reban]

Actually putting a bit more thought into it things make a bit more sense.

In T5 its not the Jump Drive that requires fuel. It actually works like this:

Molecular hydrogen is fused in the Fission PPlant which uses that process to generate energy to power the Jump Drive.

This happens in Overclock, which is when there is potential for PPlant failure.

My take is that if you risk using unrefined fuel during overclock operations you should roll Flux. Bad ([EDIT] poor or unfavorable) flux would indicate a Power failure and that is covered in the Unplanned Outcomes table p.373 as a failed jump, but i think especially bad flux should indicate a PPlant explosion.


[EDIT] Apologies for the gratuitous use of the word Actually.

 

[Midgardsormr]

I am assuming you mean a negative result on normal Flux, Bad Flux being a specific kind of Flux roll. Even so, that's a huge chance of mishap… 42% if my math is good. Certainly way higher than the 3% chance in CT (assuming no other mods from maintenance or insufficient engineering staff).

I could see it being a Mod on Reliability checks for the power system and/or drives, though. In fact, I think that's how I'll apply it—using unrefined fuel gives a -1 or -2 Mod to qRebs checks.

Wait… Less than 3%. 3% chance of a failure, then at least one roll of 7+ on three systems makes 2.4%? Anyway, it's low.

 

[Reban]

I didn't specifically mean Negative Flux. I see the Referee having a choice of rolling Flux on two columns on the Master Mods Table. One is rolling on Table 06 Potential p.181 where negative outcomes range from poor to terrible. poor might result in a shaky transition to Jumpspace, while terrible might result in PPlant failure. The second is rolling on Table 09 Severity p.182 (possibly after rolling to see if unrefined fuel causes a problem). Temporary requires a PPlant restart like a flooded engine, Devastating mean you've blown a hole in the ship.

The point is there are several ways of doing it depending on the circumstances, we're not bound to the hard 3% of CT.

Also take into account that a failure of power to the Jump Drive has the relatively trivial outcome of no jump happening not a mis-jump. The consequences of running your PPlant on unrefined fuel may be more serious, it might just cough, splutter, have to be purged and restarted or it could go boom.

I like this aspect of T5 because you can tailor rolls depending on how contaminated your unrefined fuel is. On the otherhand as the OP pointed out fuel fittings are really efficient so unless the PCs really can't spare the time or have no access to a fuel purifier the chances of needing to use unrefined fuel and having to risk the PPlant are small.

 

[esampson]

. . .So supposing a Type A Free Trader constructed at a Tech Level 12 shipyard, an appropriate refinery would be at the minimum available size of 6 tons. The smallest possible refinery in the list is TL 15 and 3 tons. . .

This is actually pretty much in agreement with T5. While the purification plant for a ship in T5 is only a single ton a High Guard ship did not need to spend an additional ton both for a fuel scoop and a fuel intake (both of which are required to refuel from either a gas giant or ocean like a High Guard ship). Additionally it was possible in CT to refuel from ice which would require yet another ton for a fuel bin.

While the T5 fuel purification systems start out smaller than the older High Guard systems they are not one of the things listed as being able to benefit from staging so in the end they would probably be larger (my experience with CT was that most ships tended to be built at TL 15).

So I don't really see fuel purification systems becoming any more prevalent than they were in CT, but then in CT I actually thought they were fairly prevalent.

 

[dalthor]

T5 has that nice little TL efficiency setup. Fuel systems, including scoop, bin, intake, purifier, and maybe even the transfer pump should be able to benefit from the efficiency standpoint.

Since the original TL is 8, I'd expect significant improvements in processing capability, but not much size reduction - your intake (pipe) size is the main consideration.

The primary limiting factor would be the purifier. You'd still have to run the full purification cycle, based on tank size, before you would be able to use the fuel as refined. Of course, you could use unrefined fuel if you wanted to accept the possible consequences.

For the scoop, bin, and intake, I'd use the regular efficiency multiplier, up to 130% at TL-12 and above. I'd set maximum size reduction to 50% of the TL-8 version - the pump/rake/grabber size decreases, but the "pipe" size wouldn't really change.

For the purifier, you could use the 130% efficiency, but that basically just increases the purifier to a max of 10.4 (round to 11) tons per hour - pretty slow compared to the intake speed, and REALLY slow as the TL goes up.

My thought on the purifier would be to allow either a multiplier per TL over 8, to a maximum multiplier of 5, or an additional 4 tons per hour to a max of 4 increases.

This would purify 8 tons/hr at TL-8, 16 tons/hr at TL-9, up to 40 tons/hr at TL-12 and above with the multiplier, or 8/12/16/20/24 tons per hour using the +4/TL increase factor.

Feedback appreciated.