CT Only: Fuel purification for drop, collapsible, and demountable tanks

[snrdg082102]

Morning all,

LBB5 introduced the use of drop tanks while CT Adventure 5 added details to the drop tank along with collapsible and two types of demountable tanks.

Could all the tanks use the fuel purification plant if any of there are installed on a ship and are there any sources that tell which ones can or cannot use the purification plants?

 

[McPerth]

I'd say yes, as the purified fuel is pumped to the tanks, and those same tanks must be connected to the drop/collapsible/dismountable tanks for them to be useful...

I've always assumed the tanks are comparimentalized, so that the fule may be purified from each comaprment sequentially. If so, the temporary tanks shuld only add compartments to the job (increasing the time needed, as rules specify too).

 

[atpollard]

I always thought of the purification plant as an addition to the fuel skimming system (which includes hoses for sucking in water, so must include pumps).

The tanks are just tanks ... big, empty spaces to hold liquids (LH2 in the case of fuel).

 

[McPerth]

I always thought of the purification plant as an addition to the fuel skimming system (which includes hoses for sucking in water, so must include pumps).

But all too often it takes more time to purify the fuel than to skimm it, so, it has to be stored somewhere while waiting for the purification plant to end its job...

 

[Timerover51]

I always thought of the purification plant as an addition to the fuel skimming system (which includes hoses for sucking in water, so must include pumps).

The tanks are just tanks ... big, empty spaces to hold liquids (LH2 in the case of fuel).

Hmm, not big empty spaces. More likely divided into compartments with baffles in case of acceleration problems. You want divided compartments in case of not using all of the fuel in one jump.

 

[atpollard]

But all too often it takes more time to purify the fuel than to skimm it, so, it has to be stored somewhere while waiting for the purification plant to end its job...

That raises the issue then of where is the requirement for excess tank capacity (to hold the unrefined fuel before it is refined and pumped into another tank ... or the issue of how you pump unrefined fuel out of a tank while simultaneously pumping refined fuel back into it, without the refined and unrefined fuels mixing.

Since none of these are dealt with in detail (thank goodness), I choose to believe that refining takes place at the time of skimming and the slower system will be the limiting factor. So a ship may need to decide whether it will spend more time skimming and refining (than skimming alone will require) or will some of the fuel be unrefined (with the jump issues associated with that).

YMMV.
... and this is definitely not a hill worth fighting over.
Just my opinion of The Traveller Book and High Guard.

 

[atpollard]

Hmm, not big empty spaces. More likely divided into compartments with baffles in case of acceleration problems. You want divided compartments in case of not using all of the fuel in one jump.

OK. I grant that.

[QUOTE="LBB5-pg49]Fuel-n: Current fuel is reduced by n% of total fuel capacity (at least 10 tons).[/QUOTE]
Suggests up to 100 compartments per ship with a 10 dTon minimum compartment size.

Of course small tanks run contrary to the need to quickly pump all of that fuel into the jump drive. Big tanks with big lines and big pumps would be more efficient than 100 garden hoses feeding the Jump Drive.

Personally, I am a fan of chemically binding the hydrogen in a compound that can be heated to quickly release it ... but I have no canon evidence for that, so it remains my personal preference and nothing more.

 

[snrdg082102]

Afternoon all,

Thanks for the highly probable answer of yes that drop, collapsible, and demountable tanks can be use the fuel purification plant.

I just read on page 13 of CT Adventure 5 TCS that fuel in collapsible tanks must be pumped into the normal fuel tanks. My guess is that a collapsible tank works the same way with the purification plant.

I have considered the fuel scoops and fuel purification plants as two separate systems. A ship that is not capable of the skimming or ocean refueling could still get fuel from ice comets or asteroids. The ship would match orbit, heat the ice, and send the mixture to the fuel purification plant.

While I was typing this I just stumbled over the tidbit that demountable tanks operate in the same manner as normal fuel tanks, CT Adventure 5 page 13. In this case the purification process is probably the same as for normal fuel tanks.

IIRC somewhere in one or more of the Traveller timelines fuel scoops are capable of ingesting a certain amount of unrefined fuel per hour, gas giant skimming takes between 8 and approximately 10 hours, ocean refueling takes something like 4 hours, and ice refueling takes about 12 hours.

Again from memory, since I can't seem to find the source for this one either, that a single properly sized fuel purification plant can process a full load of fuel in 6 hours.

Thanks again one and all.

 

[McPerth]

I have considered the fuel scoops and fuel purification plants as two separate systems. A ship that is not capable of the skimming or ocean refueling could still get fuel from ice comets or asteroids. The ship would match orbit, heat the ice, and send the mixture to the fuel purification plant.

Or refuel at staport D (no refined fuel available)...

Or wanbting to buy unrefined fuel to save 80% of hte cost...

There are many reasons to keep the fuel purifier plant on a ship, even if unable to skimm

 

[snrdg082102]

Evening PST McPerth,

Or refuel at staport D (no refined fuel available)...

Or wanbting to buy unrefined fuel to save 80% of hte cost...

There are many reasons to keep the fuel purifier plant on a ship, even if unable to skimm

Thanks for taking up the slack on the stuff I missed. In the adventure in CT AM 3 Gvurrdon's trip to Zhodani capital laid over at several ports without refined fuel.

 

[Supplement Four]

I'd say yes, too. Here's my reasoning: If a ship fills with unrefined fuel, I don't think the refining process happens as the ship is being filled. The storage tank holds the unrefined fuel, and it is processed through the fuel purification system and shot back into the J-Tanks. The tanks have baffles that can be opened and closed to keep sections of the tank sealed from the rest, so the unrefined fuel is kept separate from the refined fuel.

If this is true, then the drop/collapsible/demountable tanks must work akin to the ship's regular J-Tanks.

FYI, demountable tanks are an early plot point of the Traveller Adventure, too.

 

[Spinward Scout]

I would think drop tanks will only be used in systems where they will retrieve the drop tank after you Jump, then you probably get the drop tank to begin with from the starport. You could theoretically get an empty drop tank and go skim for fuel, but I wouldn't see the point. Someone has to go get the drop tank after you drop it unless it has a maneuver drive of it's own and a robotic brain to put it on a trajectory towards civilization. Otherwise, you're leaving the empty tank floating in space. So you're probably getting the drop tank already fueled before you head out to your Jump point.

Just my 0.02Cr

 

[Vladika]

I would think drop tanks will only be used in systems where they will retrieve the drop tank after you Jump, then you probably get the drop tank to begin with from the starport. You could theoretically get an empty drop tank and go skim for fuel, but I wouldn't see the point. Someone has to go get the drop tank after you drop it unless it has a maneuver drive of it's own and a robotic brain to put it on a trajectory towards civilization. Otherwise, you're leaving the empty tank floating in space. So you're probably getting the drop tank already fueled before you head out to your Jump point.

Just my 0.02Cr

I'd have to concur with this assessment. There would be an industry built around this service. Skimming takes time and like your garden grill, you exchange empty containers for full, or go to a commercial refueling point.

Why spend days, or more, moving to a fuel source and back out of a gravity well when you could be on a profit run for merchants or back to ready status for a warship?

 

[snrdg082102]

Morning PST Supplement Four, Spinward Scout, and Vladika,

Another yes vote from Supplement Four that drop, collapsible, and demountable fuel tanks can use fuel purification plants.

Drop tanks, as Spinward Scout suggests and Vladika clarified, under normal conditions, normal having a wide definition, probably won't be used by a ship in conjunction with fuel skimming and running the unrefined fuel through a fuel purification plant. However, I am very sure if I could think about putting unrefined fuel or refined fuel into drop tanks that someone else probably has done so.

Thanks for the continued discussion.

 

[Supplement Four]

I would think drop tanks will only be used in systems where they will retrieve the drop tank after you Jump, then you probably get the drop tank to begin with from the starport.

I could certainly see it working this way, but I also could see it working to where the drop tanks were disposable (like the tanks on the shuttle's rocket).

It depends if the economics makes sense, one way or the other. If the tanks are extremely inexpensive, relatively speaking, it may not be worth the fuel (for micro jump) and time (for M-Drive use) it takes to retrieve the drop tank.

If it takes a week for a ship to retrieve a drop tank and return to the world, that's an expensive proposition. We're talking about long, in-system travel here.

And, if a micro jump is used, both ways, that's a pretty big cost, too--is it worth it to pick up the drop tank?

 

[esampson]

I'd have to concur with this assessment. There would be an industry built around this service. Skimming takes time and like your garden grill, you exchange empty containers for full, or go to a commercial refueling point.

Why spend days, or more, moving to a fuel source and back out of a gravity well when you could be on a profit run for merchants or back to ready status for a warship?

While I agree with Spinward that the industry standard would probably be that when you picked up drop tanks they would be full I doubt that it would be the only way to purchase (or rent) drop tanks.

Using your grill analogy, yes, you can go to lots of places and exchange empty tanks for full. You can also just buy full tanks. However, it takes very little effort to additionally locate empty tanks that can be purchased, taken somewhere else, and filled. Such purchases represent a minority of cases but people still want such an option often enough and they require little enough extra effort on the part of the sellers that they aren't hard to find.

Similarly I can easily imagine that it wouldn't be all that difficult to find drop tanks that you could pick up empty, then head out to the local gas giant/ocean/comet/ice ring/whatever and fill it up yourself. The only thing that is required on the part of the business is that they not fill up one or two tanks when they are returned so they have some empties lying about for rent.

There's probably not a huge demand for the tanks because, as the adage goes, time is money and it will probably be cheaper in the long run for commercial ships to purchase filled tanks (once you add in the costs of the additional required equipment, depreciation of the ship from the additional wear and tear of a day or two of travel, extra crew salaries, etc.). However there will undoubtably be times when a tramp trader's pocket book gets so thin that it makes sense to go for the short term savings of DYI fuel.

 

[Supplement Four]

While I agree with Spinward that the industry standard would probably be that when you picked up drop tanks they would be full I doubt that it would be the only way to purchase (or rent) drop tanks.

Especially since it is canon that demountable fuel tanks can come without being full. Drop/Collapsible/Demountable tanks all seem to me to be a variation on the same item--extra fuel storage.

In The Traveller Adventure, the demountable fuel tanks are just sitting in a storage facility before the crew of the March Harrier makes a deal to purchase them. Then, the crew, themselves, install them in the ship's hold (to same money, I think).

All Drop/Collapsible/Demountable tanks have to be installed, yes? They've got to be somehow connected to the ship's main tank. It's a heck of a lot easier to install these tanks on a ship without the tanks being filled. So, I disagree that it's an industry standard that the tanks come pre-filled, though, maybe they do come with one free fill-up after installation.

I guess an argument could be made for the tanks being assembled and attached in zero-G, but even that's got to be harder, working in that enviroment, in a Vacc Suit, when the tank could be punctured or a seal cracked during the install.

Another arugment could be made that these pre-filled tanks are simply rolled into a cargo bay (demountable ones) and connected to the universal fuel cock. But, in the Traveller Adventure, I don't recall the installation being that easy. I think the install took the crew the better part of a day. And, that would be canon on how the tanks have to be installed.

 

[Spinward Scout]

I could certainly see it working this way, but I also could see it working to where the drop tanks were disposable (like the tanks on the shuttle's rocket).

At earlier TLs of space travel sure, but remember, unlike collapsable/demountable tanks that stay in the cargo hold when you Jump, drop tanks don't go with you when you Jump. They then become space debris until retrieved. I don't think too many high traffic systems would want the extra space debris floating about their system. It becomes a space hazard. The thing I see is coming out of Jump right into the path of an expended drop tank and your ship ends up the subject of the next Traveller News Service article. Boom. Although the same can happen with rogue asteroids and such.

One tank of fuel gives a retrieval ship about a month's worth of picking up drop tanks. I don't think it would be expensive for the Starport Authority to have a ship that goes around like an X-Boat Tender and picks up drop tanks. Low traffic systems might not care, but high traffic systems would almost require it.

I'm thinking that the drop tanks at the higher TLs would have some reserve fuel and have a very small maneuver drive and a robot brain to put it on a course to either get it out of the way or send it towards a retrieval point.

 

[Supplement Four]

I don't think too many high traffic systems would want the extra space debris floating about their system. It becomes a space hazard.

I'm sure high tech, high pop, high traffic systems would be as you say. I'm not so sure about other, less populated systems, unless there is a "space debris" Imperial Law.

Maybe standard procedure is to launch disposable tanks on a trajectory for the system's star? Or, maybe a trajectory for deep space outsystem (which hardly ever sees traffic, even in a high traffic system)?

Or, maybe the disposable tanks burn up upon re-entry of most worlds?

Or, maybe the disposable tanks are not jettisoned at all--they could be disposed of at the next Starport (making the disposal of them something more than just hitting a switch for explosive bolts to fire, sending them away from the ship).

I'm tending to favor the last.

 

[Supplement Four]

I'm thinking that the drop tanks at the higher TLs would have some reserve fuel and have a very small maneuver drive and a robot brain to put it on a course to either get it out of the way or send it towards a retrieval point.

Intereting thought, but from using Book 8 in the past, it seems quite costly.