## How long does it take to scoop fuel

Discuss the Traveller RPG and its many settings
F33D
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### Re: How long does it take to scoop fuel

coldwar wrote: Though reading this earlier has brought me to remember that there isn't anything covering how a ship without fuel scoops fuel up from a Gas Giant.
They can't, directly.
coldwar
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### Re: How long does it take to scoop fuel

F33D you didn't read did you. I explained that the ship that cannot skim itself has a dedicated ship that can skim fuel for it.

And thank you Jonah, I was think that would be what it would be, just wasn't entirely sure.
F33D
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### Re: How long does it take to scoop fuel

F33D you didn't read did you. I explained that the ship that cannot skim itself has a dedicated ship that can skim fuel for it.
Weird, it was cut off when I read the 1st time.
phavoc
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### Re: How long does it take to scoop fuel

So is there a formula here that's being proposed? A ship may skim 100Dtons/hr per 1,000Dtons displacement? Should smaller ships be able to fill their tanks faster (size ratio aside)?

Are there variables such as increasing speed that would increase the collection timeframe?

What about the risk to the ship itself? Is there/should there be any risk of damage at traveling with your fuel scoops open/deployed?

Is a ship more vulnerable while skimming? Maybe with your fuel scoops open you are limited to travelling at .5G, or even just 1G? Too fast and you can cause internal damage due to the strain of the atmosphere in your fuel intake machinery? Which leads to a possible new equipment modification called high-speed fuel scoops?

Or is anyone else interested in a reasonable formula?

I think tankers and other dedicated fuel-skimming ships should somehow be more efficient at doing this. Specialization should count for something.

Maybe we can put our collective heads together and come up with something?
F33D
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### Re: How long does it take to scoop fuel

phavoc wrote: Are there variables such as increasing speed that would increase the collection timeframe?
I think that the Pilot Operating Handbooks (Pilot Information Manuals) & the Spacecraft operators Manuals would have the various parameters for safe operation (skimming). Anything outside of those would require checks to avoid mishap.
AndrewW
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### Re: How long does it take to scoop fuel

Signs & Portents #87 has a fuel skimmer pinnace as part of the Death Station adventure.
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### Re: How long does it take to scoop fuel

phavoc wrote:So is there a formula here that's being proposed? A ship may skim 100Dtons/hr per 1,000Dtons displacement? Should smaller ships be able to fill their tanks faster (size ratio aside)?

Are there variables such as increasing speed that would increase the collection timeframe?

What about the risk to the ship itself? Is there/should there be any risk of damage at traveling with your fuel scoops open/deployed?

Is a ship more vulnerable while skimming? Maybe with your fuel scoops open you are limited to travelling at .5G, or even just 1G? Too fast and you can cause internal damage due to the strain of the atmosphere in your fuel intake machinery? Which leads to a possible new equipment modification called high-speed fuel scoops?

Or is anyone else interested in a reasonable formula?

I think tankers and other dedicated fuel-skimming ships should somehow be more efficient at doing this. Specialization should count for something.

Maybe we can put our collective heads together and come up with something?
Ok Streamlined ships get ONE fuel scoop for free. Additional scoops can be added for Mcr.1 (page 110) which refers to non streamlined ships but can also apply to extra scoops.
So a streamlined ship has one scoop complete with hatch. If we presume that a scoop is capable of filing a small ship in minutes given that the minimum time for a scoop run is an hour and half of that could be travel time in and out then about 5Dtons a minute covers the under 1000Dton ships with a single scoop if they spend 30 minutes scooping and a 15 minute run each way. Longer scooping runs involve more flying time not more scooping time. That gives you 300Dtons an hour
Each additional scoop allows for an extra 5Dtons per minute/300Dtons per hour.

Flight time into and out of the gas giant to reach the H level and return, Pilot + DEX, 1D6 hours with one hour removed per degree of success down to a minimum one hour. Skimming time is then based on fuel intake from number of scoops.

As has been mentioned above:

Fuel skimming is going to be done at a very low speed, flying into what amounts to a cloud of debris with a huge great hatch open is going to make you more than a little bit unstable and vulnerable to stuff getting sucked in at high speed. Given that a 6 minute space turn involves moving hundreds of Km a ship that is skimming is going to be all but standing still. No dodging and a completely predictable and easy to hit target (perhaps +2)

I would think that your sensor range becomes close, no way to see anything far away in all that fog. Perhaps if you are attacked a natural 12 results in a hit going through the scoop and either doing an auto fuel hit or doing an internal hit not a surface one.

Specialised fuel skimmers would have multiple scoops, aero fins and a lot of fuel tanks.
For example a 200Dton fuel skimmer, streamlined with Aero fins, 2G and a bridge plus a small cabin and a few days of power plant fuel would have tanks for 165Dtons of fuel, at 5Dtons a minute that would be 34 minutes and the aero fins add +2 to the pilot checking giving 2 extra effects and dropping the total skim time by two hours. Add a second scoop and it would take 17 minutes to fill its tanks. A bare bones and fairly cheap ship, all it does all day is skim and return to off load at a set of fuel tanks in orbit above the gas giants atmosphere where the customers can buy it or ship it to the main world or refuelling points at the 100D limit.
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phavoc
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### Re: How long does it take to scoop fuel

I checked S&P 87 - no info there regarding skimming.

I'll have to look at the other suggestions when I get home and have time.
tanksoldier
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### Re: How long does it take to scoop fuel

roughly 28 hours plus the time taken to purify it.
Any reason the ship can't be purifying the first load while the skimmer goes back for a second, etc?
AndrewW
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### Re: How long does it take to scoop fuel

phavoc wrote:I checked S&P 87 - no info there regarding skimming.

I'll have to look at the other suggestions when I get home and have time.
Nope, just in reference to a ship designed for that purpose.
F33D
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### Re: How long does it take to scoop fuel

tanksoldier wrote:
roughly 28 hours plus the time taken to purify it.
Any reason the ship can't be purifying the first load while the skimmer goes back for a second, etc?
If you have enough purif equipment.
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### Re: How long does it take to scoop fuel

tanksoldier wrote:
roughly 28 hours plus the time taken to purify it.
Any reason the ship can't be purifying the first load while the skimmer goes back for a second, etc?
None at all.

Say your cargo hauler has 5 fuel processors. The cutter is bringing back 30Dtons per trip so you simply start refining as soon as it makes it first unload and 24 hours later you will have refined 30Dtond of fuel roughly every 3.5 hours later. Since the 5 processors can handle 100Dtons only after the 4th cutter trip you will have to wait till one or more of the processors are finished. It’s a tiny bit of paperwork but it means you are ready to jump out as soon as possible rather than waiting till you had 100Dtons of gas in the tanks to begin purification.
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tanksoldier
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### Re: How long does it take to scoop fuel

It’s a tiny bit of paperwork but it means you are ready to jump out as soon as possible rather than waiting till you had 100Dtons of gas in the tanks to begin purification.
If you have tanks full of unrefined fuel and begun purification, where does the purified fuel go?
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### Re: How long does it take to scoop fuel

tanksoldier wrote:
It’s a tiny bit of paperwork but it means you are ready to jump out as soon as possible rather than waiting till you had 100Dtons of gas in the tanks to begin purification.
If you have tanks full of unrefined fuel and begun purification, where does the purified fuel go?
Back into the fuel tanks

To be slightly more serious.

Fuel is H, in gas form or partially in liquid form. If you have just scooped a tank full of gas from a gas giant it is going to be full of other gases, strange alien plants and life forms that live in the upper atmosphere of the gas giants, bits of hull that fell off the last ship to fail a pilot roll while skimming etc. You pump that across the filters multiple times, the gas goes back into the tanks where it mixes with the unrefined fuel but over repeated passes the volume of containments falls to an acceptable level.

Or if you have partial liquid storage you take on gas, purify it, freeze it and store the much smaller volume of liquid H into the tank you just emptied of gas. Since the liquid H takes up a much smaller volume you can pack it into a single tank while purifying several gas tanks.

If you have taken on water or any other high density source of H only some of your tanks will be full since a full load of gaseous H is going to be a much smaller volume of ammonia or other liquid of choice.
Traveller: Nonsense, those rumours about me and crashes, no truth in them at all. I never had a landing I didn't walk away from!

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phavoc
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### Re: How long does it take to scoop fuel

Isn't hydrogen stored as a gas now for fuel?

I could see freezing it and then thawing it to a liquid or gaseous state as needed, which should give you additional fuel storage (though loading frozen hydrogen might be mite impractical).
F33D
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### Re: How long does it take to scoop fuel

phavoc wrote:Isn't hydrogen stored as a gas now for fuel?

I could see freezing it and then thawing it to a liquid or gaseous state as needed, which should give you additional fuel storage (though loading frozen hydrogen might be mite impractical).
Yes, as compressed gas. Not dense enough. Thus, LHyd in Trav universe.
tanksoldier
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### Re: How long does it take to scoop fuel

If you have taken on water or any other high density source of H only some of your tanks will be full since a full load of gaseous H is going to be a much smaller volume of ammonia or other liquid of choice.
If your tanks are full of water, you have only 2/3 the hydrogen you need for full tanks.

The point is, you can't put the refined fuel back in the same tank with the unrefined fuel or you'll be running the same fuel thru the purifiers repeatedly. I suppose that could be why it takes so many hours to refine fuel.

You HAVE to refine it as you skim it or pump it in, or you have to have a "sump" tank equal in size to whatever your tank's partitioned sizes are to hold refined fuel before you dump it back into the main tanks.

If I have 30 dtons of liquid water I'm going to get, roughly, 20 dtons of liquid hydrogen and 10 dtons of liquid oxygen. Where do I put the refined hydrogen while I'm still in the middle of refining the 30 dton tank of water? I assume oxygen is simply vented over the side once life support is recharged.

Also, if I need 30 dtons of hydrogen to jump, where do I put the additional water I need to refine to get it? A ship HAS to refine fuel as it is being brought aboard. If it waits until it's tanks are full there is nowhere to shuffle fuel around while refining, assuming fuel tanks are only as large as required for the intended jump... which is the case for most ships... and if it is using a fuel source with a high percentage of waste products, like water, it's going to need to process a greater volume of raw material to get the pure hydrogen it needs. A ship which requires 30 dtons of hydrogen to jump has to process roughly 45.45 dtons of water to get it.

You can't simply fill your 30 dton tanks with water and process on the way to the 100d limit, you won't have enough fuel to jump when you get there.

Presumably a ship which is skimming can filter for hydrogen and won't have the same volume problems, but they still have the issue of where to put the refined fuel.
If you have enough purif equipment.
What difference would that make?

If I have only enough purifiers to refine 10 dtons per 12 hours, I can still get them started while the skimmer is enroute... until I run out of space to put the refined fuel.
phavoc
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### Re: How long does it take to scoop fuel

You point out some of the science-based holes in the game system.

From the description of the fuel processing (at least as I recall) you can add more processors to process your fuel in shorter time frames. But I would hazard a guess that essentially the unrefined gas is continually processed through the fuel processors until it gets to be a certain level, and any contaminants or non-hydrogen gases are vented off.

I would assume that your fuel storage is not one huge tank, but rather a series of tanks, replete with a complicated pipe system that allows the fuel to be run through the fuel processors.

Of course, if this process is HOW its done, I could see that vessels in ground ports would not be allowed to necessarily process unrefined fuel while sitting on a tarmac, as even higher levels of oxygen would be hazardous. The fix would be for an outflow hose to be hooked up and those contaminants taken away to be released/refined elsewhere. But in space you should be able to dump whatever over the side without too much worry.
F33D
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### Re: How long does it take to scoop fuel

tanksoldier wrote: If your tanks are full of water, you have only 2/3 the hydrogen you need for full tanks.
Incorrect. H2O in liquid form contains ~1.6X the H atoms as an equal volume of L-Hyd.
locarno24
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### Re: How long does it take to scoop fuel

Incorrect. H2O in liquid form contains ~1.6X the H atoms as an equal volume of L-Hyd.
Indeed. Storing hydrogen as a compound is the most space efficient way to do it - with the additional advantage of not flooding your ship with a cryogenic liquid if there's a tank breach.
If you don't mind supercooled fluids, Liquid Ammonia or Methane would be even better, with 400% storage.

The fundamental problem is that you have to split the hydrogen out to use it - because (at least according to the rulebook), the jump bubble has to be made out of hydrogen, wholly hydrogen and nothing but hydrogen. Aside from the ship, obviously. So either you process it before putting it in the tank or process it on the fly.

Not having a recognised qualification in jump physics, I shall nod my head and accept this....

WRT "where does the fuel go", you'll probably find it stays in the tanks. With a processor for 20dTons of fuel only taking 1dTon, it can't store the fuel during processing. More likely you are running the same fuel through the sifters again and again in one big loop from one end of the tank to another (think isotope centrifuge, I guess - it gets a few percent better each time).

Eventually, what's in the loop is pretty much pure hydrogen, the sensors do a couple more checks for confirmation, and the system goes 'ding!' and unlocks the jump safety protocol.
Understand that I'm not advocating violence.
I'm just saying that it's highly effective and I strongly recommend using it.

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