How long does it take to scoop fuel

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How long does it take to scoop fuel

Postby mr31337 » Mon Mar 04, 2013 10:13 pm

I have no idea. Can anybody site a reference to how long this takes? I'm looking for a rate in tons/minute or something. Also, anybody know how long to pump hydrogen?
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Re: How long does it take to scoop fuel

Postby rust » Mon Mar 04, 2013 10:36 pm

Traveller core rules, page 141:
Scooping takes 1–6 hours and requires a successful Pilot skill check.
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Re: How long does it take to scoop fuel

Postby DickTurpin » Tue Mar 05, 2013 12:39 am

The only place I have seen any reference to the rate for pumping fuel is in Starports. Under new equipment on page 111 they list Fuel Transfer Equipment which allows a tanker to transfer fuel to a ship at the rate of one ton per hour.

What they don't mention is which round they mean. A six minute ship combat round seems rather slow (over two hours to refuel a Free Trader, nearly a full day for a Heavy trader) but it aligns better with fule scooping times than the six second personal combat round which would refuel that same ship in just over two minutes.
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Re: How long does it take to scoop fuel

Postby mr31337 » Tue Mar 05, 2013 1:34 am

rust wrote:Traveller core rules, page 141:
Scooping takes 1–6 hours and requires a successful Pilot skill check.
Thanks for that. Not sure how I overlooked that.
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Re: How long does it take to scoop fuel

Postby mr31337 » Tue Mar 05, 2013 1:36 am

DickTurpin wrote:The only place I have seen any reference to the rate for pumping fuel is in Starports. Under new equipment on page 111 they list Fuel Transfer Equipment which allows a tanker to transfer fuel to a ship at the rate of one ton per hour.

What they don't mention is which round they mean. A six minute ship combat round seems rather slow (over two hours to refuel a Free Trader, nearly a full day for a Heavy trader) but it aligns better with fule scooping times than the six second personal combat round which would refuel that same ship in just over two minutes.
Of course, Starports! I knew I'd seen it someplace. I think I'd have to go with 6mins per ton personally. Thanks for the reference.
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Re: How long does it take to scoop fuel

Postby phavoc » Tue Mar 05, 2013 8:07 pm

In a writeup for my fuel harvesting station, I went a slightly different route. To fill my tanker up, it takes 8-10hrs of flight in a gas giant to gather 9,500 tons of hydrogen. I guess I could change that, but for the most part I guess it seems reasonable. Or at least it seemed reasonable to me at the time. :P

My thought process was it should take a larger ship longer to fill its tanks than a smaller ship. Though perhaps one could argue that a 300,000 ton battleship has the same amount of fuel scoops as a 100 ton scout... but somehow that seems a bit off. I would think smaller ships should be able to fill their tanks faster. Having say 500 fuel scoop inlets vs. 2 (just as an example) doesn't seem right. Larger ships, especially military ones, would not want to have extra access points in their hull.

Anyways, I'm assuming it would be up the the referee anyways if push came to shove.
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Re: How long does it take to scoop fuel

Postby locarno24 » Wed Mar 06, 2013 7:45 am

My thought process was it should take a larger ship longer to fill its tanks than a smaller ship. Though perhaps one could argue that a 300,000 ton battleship has the same amount of fuel scoops as a 100 ton scout... but somehow that seems a bit off. I would think smaller ships should be able to fill their tanks faster. Having say 500 fuel scoop inlets vs. 2 (just as an example) doesn't seem right. Larger ships, especially military ones, would not want to have extra access points in their hull.
If you've paid for a streamlined hull, though, the cost is proportional to the hull displacement - so you can assume the number of scoops scales as well.

However, just buying fuel scoops for a ship is a flat cost of MCr1, which seems to contradict that (and is why scoops on a standard hull are much more cost effective than streamlining a battleship).

Equally, you have the problem of volume vs cross-section - if you scale up a ship, the same proportion volume of tankage goes up faster than the same proportional cross-section area of fuel scoop.
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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Re: How long does it take to scoop fuel

Postby barnest2 » Wed Mar 06, 2013 8:40 am

DickTurpin wrote: Under new equipment on page 111 they list Fuel Transfer Equipment which allows a tanker to transfer fuel to a ship at the rate of one ton per hour.
What... One ton per hour? I can only imagine the writer didn't realise quite how geologically slow that is compared to even modern UNREP rates of transfer.

Go check out TCS (hello personal bias). Page 23 has much more realistic UNREP equipment. I'm not going to post details until I get the go ahead or someone else posts it first. ^^
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Re: How long does it take to scoop fuel

Postby Captain Jonah » Wed Mar 06, 2013 12:06 pm

barnest2 wrote:
DickTurpin wrote: Under new equipment on page 111 they list Fuel Transfer Equipment which allows a tanker to transfer fuel to a ship at the rate of one ton per hour.
What... One ton per hour? I can only imagine the writer didn't realise quite how geologically slow that is compared to even modern UNREP rates of transfer.

Go check out TCS (hello personal bias). Page 23 has much more realistic UNREP equipment. I'm not going to post details until I get the go ahead or someone else posts it first. ^^
Please note the OP is mistaken and the rule says per turn not per hour.

Modern Unrep fuel transfer rates vary slightly between ships but are generally around 5.5 cubic metres (0.35Dtons) a minute per refuelling connection. Larger ships which can handle multiple refuelling pipes due to having more connectors refuel much faster. A single pipe is transferring 1Dton of fuel every three minutes. That is today with our tech 8 stuff.
A single refuelling connection would allow a Free trader to refuel in an hour, scouts and Far Traders in two. Larger ships would have additional refuelling connectors and I cannot see any ship taking more than three to four hours to completely refuel.
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Re: How long does it take to scoop fuel

Postby CosmicGamer » Wed Mar 06, 2013 2:28 pm

Captain Jonah wrote: I cannot see any ship taking more than three to four hours to completely refuel.
A large ship at a small facility with less connections available than the ship can take or connections that don't reach all the way around the ship or whatever.
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Re: How long does it take to scoop fuel

Postby phavoc » Wed Mar 06, 2013 9:58 pm

locarno24 wrote:If you've paid for a streamlined hull, though, the cost is proportional to the hull displacement - so you can assume the number of scoops scales as well.

However, just buying fuel scoops for a ship is a flat cost of MCr1, which seems to contradict that (and is why scoops on a standard hull are much more cost effective than streamlining a battleship).

Equally, you have the problem of volume vs cross-section - if you scale up a ship, the same proportion volume of tankage goes up faster than the same proportional cross-section area of fuel scoop.
I sort of agree, but then also disagree. Yeah, you could scale UP fuel scoops in proportion, but then that means your larger ship has more "holes" in its armor, which causes potentially other problems (increase maintenance, more weak areas to worry about during combat, etc). I would think maybe that the size might be scaled up. Have you (or anyone else) seen someone take apart the fueling aspect in a write-up anywhere? Even old-school CT?

And yeah, the physical design of the ship will probably factor into how fast it can scoop. I'm sure a longer ship with a smaller cross-section could collect fuel better than say a sphere, since it has more surface area facing forward to collect the gases. Though that's assuming the process uses some sort of ram-scoop process, and isn't liked sucked in via a vacuum style process.

Re: The speed in refueling - I can see the transfer rates being less than the maximum capabilities of the equipment simply due to safety concerns. Hyrdrogen is going to be explosive in any form, and while vacuum refuelings offer less chances of it exploding, there is probably still going to be a reasonable safety factor built-into the process. You really don't want a pump transferring 10,000 Dtons a minute to suffer a valve or pipe failure and possibly leak that much fuel out. Not to mention that the higher pressures required for faster transfers also put your internal tankage at risk of possible blow-outs. With very disastrous consequences if you get a flame and some oxygen into the mix!
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Re: How long does it take to scoop fuel

Postby F33D » Wed Mar 06, 2013 10:38 pm

locarno24 wrote: Equally, you have the problem of volume vs cross-section - if you scale up a ship, the same proportion volume of tankage goes up faster than the same proportional cross-section area of fuel scoop.
This is quite true. Similar to the armour situation talked about on another thread.
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Re: How long does it take to scoop fuel

Postby Captain Jonah » Thu Mar 07, 2013 1:25 pm

Another thought on this one. Given the speed of a ship while scooping the actual time taken to fill the tanks is not likely to be that high.

Given that the scoops are designed simply to pick up the atmosphere in front of them and transfer it into the ships many fuel tanks where the fuel processors can shuffle it around as it is purified they are likely to be large bore pipes with hatches on the hull that open for scooping and close when not in use. I cannot see a warship having hundreds of square metres of scoops without hatches which basically represent a permanent hole in the armour.

A ship moving at 1m/second with a 14 metre square scoop is going to be picking up 1Don a second. The same ship moving at an incredibly slow 100Kph is going to be scooping nearly 28Dtons a second. Given that you can have armour hatches over the scoops the only real limits on scooping become how many other systems are also after the surface space and how the fuel tanks are designed. A series of large connecting hatches which can be opened to allow the pressure of incoming fuel to force it throughout the empty tanks.

Note that while a fairly simple design it would make any such warship that was gas giant scooping very vulnerable to attack with the scoops open and many blast walls between the fuel tanks wide open. In cannon ships are always described as being vulnerable while scooping but the combat system has no real reason why. Having whole sections of the armour open and enemy fire able to penetrate the length of the ship because the blast walls between fuel tanks have been opened would mean that even small SDBs could strike crippling blows against heavy warships if they get that luck or skilful shot.

In terms of why small ships or large ships can take the same time. Well a larger ship can have more scoops so that proportionally it is taking in the same % of total fuel in an hour. Any ship is going to have a huge volume of fuel pumps built into its tankage and structure. Given that it needs to pump some half of its fuel into the jump drive in minutes when forming the jump bubble pumping its entire fuel load over an hour or two should be no problem.

But also there is the time taken by the ship to enter the gas giant atmosphere, descend through the layers until it finds one that can be scooped for fuel then rising out of the atmosphere again.
Sometimes you could find a high layer of H and scoop quickly, other times it could take you several hours to go down through the layers to find something worth scooping.
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Re: How long does it take to scoop fuel

Postby locarno24 » Thu Mar 07, 2013 2:12 pm

In cannon ships are always described as being vulnerable while scooping but the combat system has no real reason why. Having whole sections of the armour open and enemy fire able to penetrate the length of the ship because the blast walls between fuel tanks have been opened would mean that even small SDBs could strike crippling blows against heavy warships if they get that luck or skilful shot.
Quite possibly. The 'scoop' would, as noted, probably have an armoured door, (since there's no possiblity in the space combat rules of hitting a 'weak point' like there is in ground combat), and that would be the key weak vulnerability.

The other thing worth noting (which is another reason ships mount a 'high guard' whilst fuelling) is that sensors are badly impeded during a dive. Ambushing a fuelling ship is a nasty pirate trick as (a) it's one of the few times you can sneak up on someone in space, (b) you know they don't have fuel to jump out, and (c) even if they did they're hours deep in a massive gravity well - which also means they can't flee 'down' and have to try and break past you.
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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Re: How long does it take to scoop fuel

Postby F33D » Thu Mar 07, 2013 3:07 pm

locarno24 wrote: The other thing worth noting (which is another reason ships mount a 'high guard' whilst fuelling) is that sensors are badly impeded during a dive.

A high speed trip through the atmosphere could cause ionization around the hull which screws up EM sensors.
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Re: How long does it take to scoop fuel

Postby GalagaGalaxian » Thu Mar 07, 2013 10:04 pm

Don't forget a ship would have to travel a fairly predictable course, it just can't flip around on its axis and thrust to change vectors like in space. If it tried such a thing while travelling at supersonic or hypersonic speeds atmospheric drag would probably put immense stresses on the ship's structure, possibly even ripping the vessel apart.

A scooping ship would probably have to maneuver very similarly to an aircraft to avoid excess drag and stress.
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Re: How long does it take to scoop fuel

Postby locarno24 » Mon Mar 11, 2013 8:54 am

Especially if not streamlined.
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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Re: How long does it take to scoop fuel

Postby Captain Jonah » Mon Mar 11, 2013 10:38 am

So is everyone happy with the 1-6 hours being fine regardless of ships size allowing the variable to account for how long it takes the ship to go deep enough into the gas giant to find H, a short period where it floods its tanks and then time taken to leave the gas giant again.

The same technique works in large bodies of water since with gravatic drives you simply hover with most of the hull underwater, flood the lower tanks and use the internal pumps to transfer the water to upper level tanks. Pumping the water would take longer but still entirely doable within the 1-6 hours.

Even pumping water from a stream or someone’s swimming pool is likely to be doable within the same time allowing for connecting the hoses, running them out to the water source (they are going to be fairly heavy and cumbersome) and them pumping in water at a Dton every three seconds or so. In this case again the bulk of the time is spent setting up the hoses and taking them down again afterwards. A roll of 1 perhaps meaning you can set the ship down close to the water and a roll of 6 meaning you had to set down in the car park and run the hose across people’s gardens and through the house to reach that full swimming pool.

Doing this at night and trying to keep it quiet so the locals don’t call the police is bound to be entertaining :lol:
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Re: How long does it take to scoop fuel

Postby coldwar » Mon Mar 11, 2013 10:47 am

Thats how I imagine it mostly.
1 hour skimming, preparations made found a good suitable spot enter the atmosphere load up and get back out again.
6 hour skimming, The same but, what you thought was a good spot turned out to be to dangerous so you went back out looking for another, and kept on trying to find a few good areas to enter the atmosphere. All of them unsafe till the last one, or some of them allowing you enough time to take some fuel on, but not enough on each little single dive.

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. The said ship using a small craft to skim the Gas Giant.
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Re: How long does it take to scoop fuel

Postby Captain Jonah » Mon Mar 11, 2013 11:32 am

coldwar wrote:That’s how I imagine it mostly.
1 hour skimming, preparations made found a good suitable spot enter the atmosphere load up and get back out again.
6 hour skimming, The same but, what you thought was a good spot turned out to be to dangerous so you went back out looking for another, and kept on trying to find a few good areas to enter the atmosphere. All of them unsafe till the last one, or some of them allowing you enough time to take some fuel on, but not enough on each little single dive.

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. The said ship using a small craft to skim the Gas Giant.
Small craft and dedicated re-fueler’s scoop as normal, they fill their tanks and return to the mother ship, transfer the fuel to the mother ship and rinse/repeat and get a book to read.

For example a 50Dton modular cutter fitted as a re-fueler can scoop and pick up 30Dton of fuel per trip. If the mother ship is a J2 1000Dton non streamlined freighter then she will have say 230Dton of fuel. It will therefore take 8 trips of the cutter to bring 230Dtons to the freighter or (8D6 hours) roughly 28 hours plus the time taken to purify it.
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