Crossing Empty Hexes In A J1 Ship

[Dragoner]

So far you're fine. But then you have to explain why hydrogen for power plants has to be stored as liquid hydrogen, which I don't think is possible.

Why not Deuterium ice then? The numbers don't add up anyways, so the L-Hyd vs H2O issue becomes rather a peccadillo.

My suggestion would be to go with what QSDS0.5 says.

At $20 it just isn't worth that much to me, it would just open other issues as well I bet.

But leaving the referee the impossible task of explaining to his players why their perfectly logical plan won't work is equally magic-destroying. And sloppy work to boot.

...and that is what separates the good GM's from the bad. Maybe study prestidigitation or some other art of misdirection, be creative.

Too many other things don't work as well, like the fuel tanks shattered result, where does all the liquid hydrogen go? Does it suddenly flood the ship (changing to water is no answer either)? There are a thousand questions that will never be answered, all we have are the canonical statements.

 

[CosmicGamer]

What little physics and chemistry I know is decades old and long forgotten from lack of use. I also own a very limited set of CT material which is also decades old and mostly long forgotten.

1) Is it correct that the preferred form of hydrogen fuel in Traveller is in the form of liquid hydrogen?

2) There are references in Traveller to using unrefined fuel. What exactly does this mean?
2a) Is it still liquid hydrogen but not pure?
2b) Could it be water going straight into the power plant and drives?
2c) If a ship scoops the gasses from a gas giant and stores it in gaseous state can it be put straight into the power plant and drives as unrefined fuel?

3) There is lots of talk about the amount of hydrogen in water and liquid hydrogen. What about hydrogen skimmed from the gas giant? It needs to be stored while being processed. What's it's density?

4) What are the properties of hydrogen under various temperatures?

When water gets cold enough, it freezes. When it freezes, it expands. When heated, it also would build up pressure as it tries to expand into a gas.
5) How would these pressures compare to those of hydrogen and compare the storage issues of both under a variety of temperatures.

I think there's an economic argument for service stations in the gaps along J1 routes between major worlds.

Bringing fuel to a location requires
A tanker delivering fuel that has
1) Fuel to make the jump to the refueling location.
2) Fuel to jump back.
3) Fuel to drop off at the refueling station.

With just a cursory glance, it seams that economically, it's better to just put your cargo on the "tanker" instead of the fuel it is dropping off. Let it cross the gap.
2)

 

[rancke]

At $20 it just isn't worth that much to me, it would just open other issues as well I bet.

No no no no no no no no no no no no no no!!! I'm not in any way suggesting you should do anything other than what works best for you in your own personal campaign! You go and do whatever you think is best with my blessing (You don't need it, but you have it nevertheless). I'm solely talking about what I believe TPTB ought to do in future official publications. (Which when it comes to canon can be summed up thusly: "If canon isn't broken, don't change it. If it IS broken, DO change it (to something that isn't broken ).")

...and that is what separates the good GM's from the bad. Maybe study prestidigitation or some other art of misdirection, be creative.

Bad referees are people too. The bad referees (not to mention their players :devil are the ones that need the rules to work without a supply for inspiration and creativity. Rules that rely on the referre to plug the holes are Bad Rules. It really is no excuse whatsoever that good referees can handle it.

Come to that, even good referees benefit from good rules. Allows them to expend their energy and inspiration and creativity on improving the adventures.


Hans

 

[rancke]

Bringing fuel to a location requires
A tanker delivering fuel that has
1) Fuel to make the jump to the refueling location.
2) Fuel to jump back.
3) Fuel to drop off at the refueling station.

With just a cursory glance, it seams that economically, it's better to just put your cargo on the "tanker" instead of the fuel it is dropping off. Let it cross the gap.

It's would not usually be the same people who run the way station and the ships. In the example I gave, the way station would be run by a company based in Tee-Tee-Tee that used a jump-1 tanker to bring fuel to the station (maybe in the form of water even ). The ships would jump between Dodds and Trin and refuel at the station.

What you suggest may be true for a jump-1 ship that might lose 15% of its payload by carrying along fuel for a second jump. It's definitely not true for a jump-3 ships that would have its payload all but eliminated by carrying along fuel for a second jump-3.


Hans

 

[Dragoner]

No no no no no no no no no no no no no no!!! I'm not in any way suggesting you should do anything other than what works best for you in your own personal campaign! You go and do whatever you think is best with my blessing (You don't need it, but you have it nevertheless). I'm solely talking about what I believe TPTB ought to do in future official publications. (Which when it comes to canon can be summed up thusly: "If canon isn't broken, don't change it. If it IS broken, DO change it (to something that isn't broken ).")

Oh, I can assure you I do what I like IMTU. What is broken or not is another issue. Though IMO (and not to toot my own horn too much, but I am a business major right now and just made the dean's list for academic excellence), from a business standpoint, making rules too complex reduces playability. Which alienates new players, the D&D 3.5 vs 4e discussions exemplify that. What Traveller needs, and fell apart somewhat in doing, is more coherent adventures, switching midstream from the Marches to the Solomani Rim was not a good idea because the two areas are too far apart to become an arch for the adventurers to campaign in both areas. Various sectors adjacent to the Marches should have been developed with adventures and campaigns. I do this in my Imperium 1133 stuff, once it reaches a critical mass, it will be fine.

Bad referees are people too. The bad referees (not to mention their players :devil are the ones that need the rules to work without a supply for inspiration and creativity. Rules that rely on the referre to plug the holes are Bad Rules. It really is no excuse whatsoever that good referees can handle it.

Come to that, even good referees benefit from good rules. Allows them to expend their energy and inspiration and creativity on improving the adventures.


Hans

To carry on from above, the rules are actually ok, some creativity has to be involved as it is an RPG. What lacks and what would help, is written adventures, which help both good and bad GM's, because as an RPG, that is the bedrock of the game.

 

[Xerxeskingofking]

It's would not usually be the same people who run the way station and the ships. In the example I gave, the way station would be run by a company based in Tee-Tee-Tee that used a jump-1 tanker to bring fuel to the station (maybe in the form of water even ). The ships would jump between Dodds and Trin and refuel at the station.

What you suggest may be true for a jump-1 ship that might lose 15% of its payload by carrying along fuel for a second jump. It's definitely not true for a jump-3 ships that would have its payload all but eliminated by carrying along fuel for a second jump-3.


Hans

but a jump 3 tanker would need to devote 60% of it's hull to it's own fuel anyway, plus it's own J Drive, M Drive and P plant, bridge, crew quarters ect. it would need to be HUGE to transport a useful amount of fuel.

thats part of the reason why i think a refueling station would be early stellar thing, where ships are J1. a J1 tanker can have 20% for it's fuel, slap on J1, M1 drives and P-plant, a few crew rooms, and the rest as "cargo" tank space. say, for arguements sake, you can use 50% of the hull as spare fuel, or eough to refuel 5 1 jump ships the same size of the tanker. in all likeyhood, it's higher than that, but i havn't worked out any examples. (might do, though)

as soon you hit J2, the tankers starts looking less vaiable. for one, you lose 40% of your hull to your fuel, and, assuming you can cram the drives and crew spaces into 10% of the hull and still have 50% cargo, then you have, at best 2 and a half jumps worth of fuel for a same size ship. I honestly don't think you can make a sub capital ship that is J2, with 2 jumps fuel and has 50% free space.


At J3, i think you're looking at 2 trips worth of fuel to fuel a single J3 trip onwards. it goes downhill form their

 

[MarianLH]

I'm sorry I triggered an argument.

I have another question: when a ship jumps, can an observer determine where they jumped to? If so, how?

 

[Dragoner]

I'm sorry I triggered an argument.

I have another question: when a ship jumps, can an observer determine where they jumped to? If so, how?

Don't worry about it, this issue raises it's head all the time, don't be afraid to ask questions.

As far as I know, an observer can't determine where a ship is jumping to by watching it jump.

 

[rancke]

but a jump 3 tanker would need to devote 60% of it's hull to it's own fuel anyway, plus it's own J Drive, M Drive and P plant, bridge, crew quarters ect. it would need to be HUGE to transport a useful amount of fuel.

Check out a map of Trin's Veil Subsector while reading my example. The commercial traffic is J3+J3 between Dodds and Trin via a way station in 3037; the fuel is delivered to the way station from Tee-Tee-Tee by jump-1. (If the tanker is designed right it even uses less fuel going home empty than it does going out full).


Hans

 

[Xerxeskingofking]

Check out a map of Trin's Veil Subsector while reading my example. The commercial traffic is J3+J3 between Dodds and Trin via a way station in 3037; the fuel is delivered to the way station from Tee-Tee-Tee by jump-1. (If the tanker is designed right it even uses less fuel going home empty than it does going out full).


Hans

see, thats a J1 tanker, supplying fuel to change a 3 jump j3 route into a 2 jump j3 route (a j3 ship could go via Tee-Tee-Tee and Prilissa). I'd argue that such a venture could be feasible, but not profitable, barring some sort of trouble on Prilissa, some sort of time sensitive goods travelling form Trin to Dodds.

but that's My Opinion, not fact.

I have another question: when a ship jumps, can an observer determine where they jumped to? If so, how?

I think you could make a gross guesss based on thier exit vector (ie where on the 100D limit they jump form and what is in that direction), but thats not cannon.

 

[leo knight]

IMTU, all my Free Traders had collapsible tanks for the longer runs. I usually worked out where they were stowed, and which areas they took up when filled.

One of the first SF novels I ever read was "Captives in Space" a Dig Allen book from 1960. They make mention of the loss of a passenger liner. The hydrogen tanks leaked, and made a volatile mix with the oxygen from the cabin area. The resulting flash fire killed everyone on board. I don't know if something like that could truly happen, but the characters were horrified by the prospect, and it left quite an impression on me.

Just so I understand, for future reference, water would be about 60% the volume of liquid hydrogen for the same amount of fuel? And methane about the same? Personally, the idea of storing fuel like that, with electrolyzers and stills working away down in the bilges, appeals to me. Seems almost steampunk.

 

[aramis]

Factors that are big enough to make a significant difference at the scale of the game should be fixed. Take for example the power plant fuel consumption. If you have a ship with a cargo space of, say, 80T that uses 20T of hydrogen per month, carrying that hydrogen as water would increase the available cargo space by almost 10%. I can tell you that that would make a significant difference to the profitability of a ship.

WHile it would increase the volume by about 7.15 tons, it would reduce the available mass by about 175 tons, and still require the jump fuel (which is used faster than it can be electrolyzed) be LHyd.

And Traveller PP fuel rates imply an energy capture of about 100.0001 times the energy used to operate the plant...

 

[whartung]

There are several issues with carrying water for hydrogen.

The first is basically temperature and pressure. The tanks and fuel system needs to be able to cool and manage the L-Hyd, as well as the pressure from any of the off gassing of the hydrogen. I think it's pretty well assumed that when there's empty space in a fuel tank, it's not in vacuum, but rather filled with hydrogen gas.

I'm no physicist, but I would like to think that the pressures of hydrogen in a gaseous state may not be higher then when it's in its liquid, near boiling state. Ideally if the pressure gets too high, then the hydrogen will collapse back in to liquid, thus helping the entire system maintain some kind of steady state.

For water, the problem is keeping the water liquid. Water freezes really easily in the cold of space, and frozen water expansion wreaks havoc on everything. Few systems are designed to withstand the pressures of freezing water.

That suggests that the potential for disaster if something with the insulation or heating were to fail would be pretty dramatic, and I think that situation is simply too easy to mistakenly happen. With L-Hyd if all else fails you can vent it out as gas or liquid.

The next is the potential density issue with water and whether or not the ships, or holds, are built to handled loads that big, with that much density. A 20 ton may be only able to hold 10 ton of water, perhaps.

Since volume is the precious commodity of jump travel, I would imaging that if water brought that much of a benefit then things like tanker fleets would rely somewhat on water just to get that much more fuel on to the other side of the jump. Or that there would be some chatter of water filled tankers being used to fill deep space fueling depots, etc.

Next, while the hydrogen density of FRESH water is quite good, what about SALT water? Is that enough to tip the scales? Most water used for fuel (as in dipped water) is likely to be from salt water. So, perhaps that's enough loss because of all the new salt to make it even more uneconomical to use water at this level.

Finally, while oceans are common, gas giants are more common, and gas giant raw materials likely require less energy overall to process in to L-Hyd. I don't think anyone has really explored where a starport sources all of its refined, or even unrefined, fuel. Does it lift it out of the local planet gravity well from it oceans, or is there an ongoing tanker train to the near GG?

A tanker train can be mostly automated (no need for a lot of crews). You basically need a tug fleet to catch and launch unmanned tanks to and from the GG. Hulls are cheap enough to have a reasonable amount of them in transit to keep the starport in fuel. Dunno if this is cheaper than lifting water or L-Hyd from ground base processing stations. I imagine some local environmentalists might nit pick about the effects of water being removed forever from the planets eco-system.

So, anyway, I think there can be a lot of issues with water and why it's not an ubiquitous, higher density form of hydrogen storage in the large.

 

[warwizard]

I would expect unrefined fuel to be a mix of H2 noble gases, ammonia and methane, as it is collected from a gas giantyour fuel purification plant can handle H2O, Ammonia and Methane and seperate out the noble gasses.
I see no cannon reason you could not ship "pure" Ammonia or Methane for later refining and storage as liquid H2.

From a fluf point of view you could inflate the jump bubbles with methane or strip the carbon out of the ammonia and likley be just fine, not generating an explosive atmosphere in the jump bubble, as stated previously, I would not do the same with water, but as the OP said the extra fuel is not stored in the tanks for the H2, so whatever it is, it's just a feed stock for the purifier.

The Cannon's dangers of using unrefined fuel in jump drives and power plants may be due to clogging of injector nozzles, erosion of the same, or poisioning of gaskets and seals intended to touch only hydrogen, or whatever other fluff you want to present to your players.

 

[Icosahedron]

30 years ago, I had a think about fuel storage and came up with some rationales - they may not hold water (excuse the pun, I just had to do it) but they work for me.

1. Pondering the 'volume not mass' problem in CT (long before MT came out) I decided that ships have an overall density of 1 tonne mass per m^3, like a terrestrial submarine. The lighter components (such as fuel tankage) balance the hevier components (such as drives). If the fuel was water, this wouldn't happen.

2. Hydrogen is NOT fuel for a fusion reactor, but potentially Deuterium is. So I figured refined fuel is deuterium and unrefined is Hydrogen. The refining process not only separates out other gases, but also the Proteum. Hence your ecology is not affected since the 'depleted water' is returned to source.

However, neither of these arguments prevent you from carrying water in your hold and converting it to fuel enroute.

As a GM, though, I would simply rule that carrying your fuel as water is a non-standard procedure. As Whartung suggests, there may be specific safety problems if everything doesn't work just right, there may also be losses in the conversion process (perhaps when skimming and dipping surplus material is used for cooling the refinery), and I would simply not allow the form of the fuel to provide the players with an advantage.
Yes, they are handwaves, and the players would know they are handwaves, but the players also know they're trying to pull a fast one by suggesting water in the first place, so it all balances out. NO 1.6 = 1 in my game. End of...