#### Vidgar

##### Banded Mongoose
Greetings All,

Newbie GM here, but 40s years playing.

I need to clarify a technical question about Fuel Skimming?

High Guard p37 states 1T of Fuel Processor will turn unrefined fuel (brought or skimmed) into 20T of refined fuel in a 24 hour period.
Mathematics: A ship can do approximately 250 (7 minutes) passes in a 24 hour period. This means 1 pass give approximately 0.08T of fuel per 1T of Fuel processor.

Traveller Companion Pg 156 talk about 1% of the ship hull tonnage per 2D (Average 7) minute pass through a gas giant (depending on layer).
Mathematics: In a 24 hour period, a ship can do 250 passes, as above. This mean any and all ships will produce 250% of the hull tonnage with one 1T of Fuel processor in one day.
So a 200T Far traders with one 1T of Fuel processor would fill it's 41 ton bank in an average of 140 minutes.
While a 2000 T ship with one 1T of Fuel processor would fill it's 41 ton fuel bank in an average of 14.35 minutes.
Have I stuff up my mathematics or is it a typo?

I have assume Traveller Companion Pg 156 is a typo. It should read: A ship can skim fuel equal to 1% of its hull Fuel Processor tonnage per pass, with a pass typically requiring 2D minutes. The would change the mathematics back to; One pass of a ship with a 1T of Fuel processor would refined 0.01T of fuel. So over 250 passes, it would process 25 Tons of fuel. You would more fuel faster, buy 2T of Fuel Processor.

Technically, the percentage should be 0.08%, by why turn the game into an ACCOUNTING class.

Why have I ask this question, I am running the Island in the Reft adventure as my 2nd game, and there is a mined Gas Giant. I just want to make sure I have the concept right.

Does anyone have experience with this adventure, and have any idea?

Thanks you
Vidgar

A ship can skim unrefined fuel equal to 1% of its hull tonnage in a single pass. Fuel processors (if present) can each turn 20 tons of that fuel into refined fuel in 24 hours. A ship that plans to skim fuel usually has enough fuel processors to convert its full fuel capacity in a day or two. Fuel processors have no effect on skimming rate, all they do is purify the fuel after it is gathered.

Actually I had a slightly different question that I have wondered about. Say a ship skims X tons of unrefined fuel and the fuel processor starts turning that to refined fuel. If during this time, something interrupts, do I have Y tons of fully refined fuel and X-Y tons of unrefined fuel, or do I have the X tons of slightly less unrefined fuel? In other words, is there some kind of separate compartment to store unrefined vs refined fuel or does it all go into one big tank and the processor is like the filter in a pool, and just sucking in the unrefined fuel over and over again, purifying it more and more until it reaches a purity level sufficient to meet the refined fuel definition?

You could probably do both.

I'd say it would depend on the plumbing and tank arrangements, one reason I'd have separate tanks, where you could fill them with different fluids.

If you have a single tank, you're probably stuck with gradual refinement.

As @DickTurpin points out there is no linkage between the fuel skimming rate and the refining rate. Yes a ship can fill tanks in a couple of hours and then spend days (depending on the size of their refining plant) to refine the fuel.

Bear in mind that it may take a ship another day or so to travel from the surface of the gas giant to the 100D jump limit and that time can usefully be spent refining.

Addendum: and your assumption of a typo in the Companion is incorrect. Ships do not even need fuel processors to skim, although it may imply they are jumping on unrefined fuel if they are not just dedicated fuel collectors.

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Actually I had a slightly different question that I have wondered about. Say a ship skims X tons of unrefined fuel and the fuel processor starts turning that to refined fuel. If during this time, something interrupts, do I have Y tons of fully refined fuel and X-Y tons of unrefined fuel, or do I have the X tons of slightly less unrefined fuel? In other words, is there some kind of separate compartment to store unrefined vs refined fuel or does it all go into one big tank and the processor is like the filter in a pool, and just sucking in the unrefined fuel over and over again, purifying it more and more until it reaches a purity level sufficient to meet the refined fuel definition?
I would assume the "fuel tanks" are divided into smaller tanks so we can trim the balance of the craft. So, I would guess you refine a sub-tank at a time. In effect, after a while you have Y tons of refined fuel, and the rest is still unrefined.

Speaking of which, you could have a single tank, and install a separator, whether a membrane or something more metallic. On rails.

Speaking of which, you could have a single tank, and install a separator, whether a membrane or something more metallic. On rails.
Yes, that is what I have in my head for my groups. Essentially all fuel tanks internally have two collapsible tanks inside. One is for unrefined fuel and the other for refined fuel.
I think that the spaceports would have different fillers for refined fuel and unrefined fuel with corresponding inlets for the ship. This will also make sure that you can't accidently cross contaminate fuel.

Yes, that is what I have in my head for my groups. Essentially all fuel tanks internally have two collapsible tanks inside. One is for unrefined fuel and the other for refined fuel.
I think that the spaceports would have different fillers for refined fuel and unrefined fuel with corresponding inlets for the ship. This will also make sure that you can't accidently cross contaminate fuel.
We have a carpet cleaner that works that way - tank for clean water, collapsible plastic bag inside for the dirty water - net result, same amount of liquid - plus some carpet gunk. Don't have a purifier for the carpet gunk, though...

Fuel cannot be pumped directly from these tanks to the jump drive, so a ship must complete a jump before it can use fuel stored in collapsible tanks.

That is referring to an entirely different thing. Those collapsible tanks are fuel stored in the cargo hold, which has no connection to the jump drives. Having collapsible compartments inside the fuel tanks would not have that problem.

The Starship Operator's Manual/Guide which is currently being written does address this; tanks are segmented due to the necessity of slosh baffles, and it goes a step further to prevent excessive fuel loss due to ruptures and other reasons. As a consequence, they're essentially made up of 1 dTon "cells" and the purifier can do its thing with each one individually.

And those of you that pointed it out are correct that fuel scooping and purification are two completely separate beasts; for one, every Aerodynamic hull gets a fuel scoop as a freebie, irrespective of whether it has a fuel purification plant or not.

As an interesting aside/bonus info, I was re-reading the Companion's rules on Fuel Scooping the other day and sat down to calculate the success rates of ships attempting to fuel scoop from the safest scoop-able layer of Gas Giants without suffering hull damage; A skill 0 pilot has a 26.41% chance of completing a scoop without suffering hull damage. As Piloting skill increases from 0 to 5, the chance improves to Pilot 1: 48.86%, Pilot 2: 70.2175%, Pilot 3: 86.589%, Pilot 4: 95.4254% and finally, at Pilot 5: 99.0753% (these all assume no DMs are being applied due to Gas Giant turbulence).
The average scoop time for a J-2 ship (20 passes each averaging 7 minutes, multiplied by 10 for being scooped from the Extreme Shallow) would be 1400 minutes, or 23.333... hours. That said, it could take anywhere from as little as 400 minutes (6.666... hours) up to 2400 minutes (40 hours).

As you can see, scooping takes a while (unless you're willing to venture deeper into the gas giant, which is... not advisable), and considering that most ships with Purification Plants can refine their entire fuel tankage in about 24 hours' time... it's really a a refine-as-you-scoop situation so you aren't wasting even more time.

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House Rule:
I don't see where getting buffeted by the gas giant's winds would do more damage to the hull, thereby triggering critical hits than the shaking would to internal systems and possibly weakening some hull.
I have them roll a piloting skill. Effect of success means faster skimming. The negative effect of the roll is the number of critical hits rolled. Duplicates progress the severity by one level and none are applied until all rolls are finished. (Also make the pilot roll the crits with the same dice they failed with)

Also make the pilot roll the crits with the same dice they failed with
You monster.

Greetings All,

Newbie GM here, but 40s years playing.

I need to clarify a technical question about Fuel Skimming?

High Guard p37 states 1T of Fuel Processor will turn unrefined fuel (brought or skimmed) into 20T of refined fuel in a 24 hour period.
Mathematics: A ship can do approximately 250 (7 minutes) passes in a 24 hour period. This means 1 pass give approximately 0.08T of fuel per 1T of Fuel processor.

Traveller Companion Pg 156 talk about 1% of the ship hull tonnage per 2D (Average 7) minute pass through a gas giant (depending on layer).
Mathematics: In a 24 hour period, a ship can do 250 passes, as above. This mean any and all ships will produce 250% of the hull tonnage with one 1T of Fuel processor in one day.
So a 200T Far traders with one 1T of Fuel processor would fill it's 41 ton bank in an average of 140 minutes.
While a 2000 T ship with one 1T of Fuel processor would fill it's 41 ton fuel bank in an average of 14.35 minutes.
Have I stuff up my mathematics or is it a typo?

I have assume Traveller Companion Pg 156 is a typo. It should read: A ship can skim fuel equal to 1% of its hull Fuel Processor tonnage per pass, with a pass typically requiring 2D minutes. The would change the mathematics back to; One pass of a ship with a 1T of Fuel processor would refined 0.01T of fuel. So over 250 passes, it would process 25 Tons of fuel. You would more fuel faster, buy 2T of Fuel Processor.

Technically, the percentage should be 0.08%, by why turn the game into an ACCOUNTING class.

Why have I ask this question, I am running the Island in the Reft adventure as my 2nd game, and there is a mined Gas Giant. I just want to make sure I have the concept right.

Does anyone have experience with this adventure, and have any idea?

Thanks you
Vidgar
Greetings All,

Thank you for the quick response, and you have given me many thing to think about.

1) Skimming rate can be independent to the refining rate, if required. (MOST IMPORTANT bit)
2) I particularly do not want to start a scientific debate of the theorical structure of refined and unfined "fuel" and the conversion methods.
3) From the comment, there is no reduction of volume when 1 ton of unrefined fuel is processed into 1 ton refined fuel (apparently). Since there is no conversion rate in the rule and this was probably not consider back in 1970s. It work if you like the collapsible (bladder) tanks method. Fly in, slim and fill your tanks, and then refine it over the next day or so, as you fly away. Fair enough.
4) A point raised by GAVAIN is spaceport selling Unrefined fuel. Why would they? Two set of the probably the same equipment, one making at 500Cr/Ton and the other at 100Cr/Ton. It's great for shipowners but cheap and refined it while you are sitting at the dock or in space.
5) The information form GabrielGABFonseca is interesting "refining as you scoop" (skim) in the Extreme Shallow take 24 hours and is relativity low to zero risk but it would take 200 passes. This is bad if your gas gaint is mined (Island of the Reft). Also, I would be interested in seeing your numbers for "refining as you scoop" at Shallow. The scooping time is 20%, but you refining time is the same (24 hours), and more risk.

Again Thank you all
Vidgar

#### ​

Not can be, is different. Consider making coffee or tea. The speed at which your tap delivers water does nothing to impact the amount of drink you can brew at once. The size of you kettle governs amount of drink.

Skimming is pouring from the tap, refining is the kettle you brew in. Two different things, but they work together to bring you fresh coffee.

In theory, reconfiguring the skimming inlets should increase the collection rate.

Sorry, I was not specific enough, and I like the Coffee image.
As Condottiere said, you could fly at a speed, or change your inlets, so the rate of volume skim would match the Refining rate.
Or simply skim at the maximum, fill up and refine as you fly to the Jump point.

Unrelated question:
Why do mountaineer drink Coffee on the mountain top, instead of Tea?

Boiling point?

Condottiere win
Yes higher up the mountain, water boils at a lower temperature. Tea needs 95-98 degree C to brew correct.

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