Fuel and jumping

[Vormaerin]

The T5 hull grid is a network of cables of undefined material, as is stated in MWM's article. T5 uses lanthanum in the drive coils, not the hull network/grid.

And again I will mention that in the setting the megacorporations are doing exactly that in the core sectors and wish to expand this into the Spinward Marches, with local shipyards winning contracts to build the tanks. Many Marches "interest groups" appear to not want greater Imperial authority and megacorporation involvement.

you are talking like you are disagreeing with me about something, but I can't see what it is. What the grid is made of is of is irrelevant to its existence and effect on gameplay. It is specifically defined as containing the jump field so that it doesn't affect objects around the ship.

I am aware of the storyline of drop tanks. I've been playing Traveller nearly as long as you have (I started in 1980). And if they hadn't wrecked the 3I, drop tanks would have radically restructured ship building and trade. Yes, starting in the Core and taking a moderately long time to reach the fringes, like most technologies.

The setting conceit that most ships are low jump is based around the fact that high jump requires a seriously constraining level of ship volume expended on internal L-Hyd tanks. Putting a Jump 5 or Jump 6 drive in a ship is not a problem. Spending 50 or 60% of your volume on fuel is. The increased fuel cost on jumps is easily offset by the additional cargo capacity (and the cost savings on getting the cargo moved on less hulls and fewer crews. Military ships would probably want some internal fuel capacity to avoid "the battle riders are trapped" syndrome. But they'd probably have J-6 drives and maybe J-1 or J-2 fuel for an emergency escape and use the rest of the free hull capacity for mohr dakka.

And that's fine if that's what one wants. The only thing I objected to is this idea that some other posters appear to be presenting that because drop tanks are defined in the rules as less than optimized at the moment, that it makes any sense to think they'd stay that way for long. They are, imho, that big of a game changer. No one's going to leave them on the not quite finished list for long.

Anyway, none of this has anything to do with what the initial question of the thread was about. And this is starting to feel to me like its shifting from discussion to argument. If that's my fault, I apologize. Regardless, I am not interested in arguing and I discussed my POV on the issue. So, ttyl

 

[Subzero001]

Drop tanks are the worst. Large corporations *should* have networks of drop tanks & drop tank recovery vehicles along major trade lines so they can operate massively more efficient ships. Sure, the game says some 'it is risky' stuff, but the financial pay off is so huge that this problem would be solved in short order. Tramp ships and small liners probably can't afford it, but what else is new?

And clearly it's not *that* risky because they have entire ship classes using it and they had TAS reports about running lines based on drop tanks out to the Marches from the Core.

Edit: Though large starports might have companies that just consist of drop tanks and drop tank recovery vehicles for indie ships. I think the big boys would probably squeeze that line out of action, though, just like they do most of the rest of the big port action.

what keeps you from putting a small delay in the computer with "drop tanks" assuming tech lvl 14 or 15 to just float out of the danger zone or have an "advanced drop tank" with a robo brain and enough of a movement drive to "get out of the way of the Jump thingy!?" (then there is no loss). There is a TAS designed around this called "Jump station" on the standard "drop Tank", also there is jump drive on rails article "freelance traveller I believe", you could just design a detachable hull with a jump drive, maneuver drive, fuel and computer brain similar to the hyper-drive in starwars for their fighters. Also the fuel tanker or "long hose" if equiped with a robo brain and maneuver dive would work as well. But all this all beyond the 70's era thought process.

 

[Condottiere]

1. Drop tanks disrupt the economic model of all on board starships, so it's a sort of an irritant.

2. Chances of destruction were linked to the technological level that they and/or the starship were manufactured at.

3. You could always reinforce and/or armour the hull of the drop tanks, or even turn them into spacecraft, that can accelerate away from the starship once the tanks are emptied.

 

[Sigtrygg]

I would imagine in the sectors it's used in they would have tugs retrieving spent drop tanks for refurbishment/reuse.

They are destroyed on use.

 

[Sigtrygg]

you are talking like you are disagreeing with me about something, but I can't see what it is. What the grid is made of is of is irrelevant to its existence and effect on gameplay. It is specifically defined as containing the jump field so that it doesn't affect objects around the ship.

I am aware of the storyline of drop tanks. I've been playing Traveller nearly as long as you have (I started in 1980). And if they hadn't wrecked the 3I, drop tanks would have radically restructured ship building and trade. Yes, starting in the Core and taking a moderately long time to reach the fringes, like most technologies.

The setting conceit that most ships are low jump is based around the fact that high jump requires a seriously constraining level of ship volume expended on internal L-Hyd tanks. Putting a Jump 5 or Jump 6 drive in a ship is not a problem. Spending 50 or 60% of your volume on fuel is. The increased fuel cost on jumps is easily offset by the additional cargo capacity (and the cost savings on getting the cargo moved on less hulls and fewer crews. Military ships would probably want some internal fuel capacity to avoid "the battle riders are trapped" syndrome. But they'd probably have J-6 drives and maybe J-1 or J-2 fuel for an emergency escape and use the rest of the free hull capacity for mohr dakka.

And that's fine if that's what one wants. The only thing I objected to is this idea that some other posters appear to be presenting that because drop tanks are defined in the rules as less than optimized at the moment, that it makes any sense to think they'd stay that way for long. They are, imho, that big of a game changer. No one's going to leave them on the not quite finished list for long.

Anyway, none of this has anything to do with what the initial question of the thread was about. And this is starting to feel to me like its shifting from discussion to argument. If that's my fault, I apologize. Regardless, I am not interested in arguing and I discussed my POV on the issue. So, ttyl

Sorry, my posting style can be a bit terse, I am in agreement with you, the wholesale adoption of drop tanks would have changed the setting, fortunately the FFW and then the Rebellion did for that

 

[Shadowblayde99]

After reading a lot of the posts on this topic, there is only one thing left to discuss: liquid hydrogen is very dangerous. It tends to go boom. And we are flying in a ship with tonnes of the stuff....... and if someone fires a gun at the ship? I feel like we're in the Hindenburg.

 

[Reisender]

After reading a lot of the posts on this topic, there is only one thing left to discuss: liquid hydrogen is very dangerous. It tends to go boom. And we are flying in a ship with tonnes of the stuff....... and if someone fires a gun at the ship? I feel like we're in the Hindenburg.

There is no oxygen in space.

 

[Arkathan]

After reading a lot of the posts on this topic, there is only one thing left to discuss: liquid hydrogen is very dangerous. It tends to go boom. And we are flying in a ship with tonnes of the stuff....... and if someone fires a gun at the ship? I feel like we're in the Hindenburg.

The fuel tanks are not open bladders... except maybe the collapsible one in the cargo bay.

 

[paltrysum]

It does not burn the fuel required for jump through the ship's 7-days in jump.

Am I correct?

That’s correct. Otherwise, how would drop tanks work? The fuel gets used to get you into jump.

 

[Subzero001]

That’s correct. Otherwise, how would drop tanks work? The fuel gets used to get you into jump.

The fuel in mongoose 2nd edition burns the fuel in the power-plant and the power-plant supplies the power (power points) to the jump drive to do its thing.. so providing fuel in a external tank shouldn't be an issue. But some how breaks 3I rules even though the mega-corps and military of the time use them. Originally in mongoose 1st edition there was a ship I was basing my argument on but they decided not to upgrade it in the 2nd edition I guess. 2nd edition being more in line to what was published in T5.

 

[Vormaerin]

The jump drive's size is based on the volume of material it can move into jump space. External fuel tanks take up volume. So if you are bringing them with you into jump space to provide fuel for use over the week in travel, then your ship's jump rating is reduced by that additional volume.

However, since drop tanks are a thing in the rules and have been since early on, that fuel *must* be consumed in the few minutes prior to actually jumping so that the tanks can be detached and that volume is not going into jumpspace with you.

 

[Subzero001]

The jump drive's size is based on the volume of material it can move into jump space. External fuel tanks take up volume. So if you are bringing them with you into jump space to provide fuel for use over the week in travel, then your ship's jump rating is reduced by that additional volume.

However, since drop tanks are a thing in the rules and have been since early on, that fuel *must* be consumed in the few minutes prior to actually jumping so that the tanks can be detached and that volume is not going into jumpspace with you.

"Bulk Hauler (Oukhaha class): Oukhaha-class freighters are the backbone of many corporations in the Hierate. The Hauler consists of a central ‘drive spine’ to which cargo pods are attached using mechanical clamps. Fuel is stored in long fin-shaped tanks that can be collapsed and withdrawn into the central spine when empty, to make it easier for shuttles to access the cargo pods."(1st edition Mongoose Aslan)

"However, since drop tanks are a thing in the rules and have been since early on, that fuel *must* be consumed in the few minutes prior to actually jumping so that the tanks can be detached and that volume is not going into jumpspace with you."

Actually it was to be transferred to internal fuel tanks before being used in the "jump drive" but this design countered that because of "collapsible bladder tanks / i.e. drop tanks", and now in second edition mongoose we have power points instead so this should be moot where the fuel comes from because it is burned in the power-plant (i.e power points) and since were jumping with power points we can pull them from batteries, collectors, black globes, power-plants etc.. to be put in the jump drive compactors to "jump" (they originally exampled the Xboat jumping from batteries no fuel needed for jump).

In my ATU (trying to just bend and not to break the MTU RAW of 3I) there are high capacity batteries incorporated into the jump drive unit so effectively a ship in trouble could respinn up the the jump drive immediately and flee, since during the week in jump the batteries are being trickle charged. In the first edition I added extra fuel capacity for a Jump 1 for fleeing for that purpose mainly on military ships or scouts but it did make it on other ships because of ex-military/scouts personnel. In that game I also reversed engineered the annic nova (jump 2 and jump 3 drive = jump 6 if operational) black box jump drive (to develop a jump 9 ship via twin jump 3 drives when operational i.e a alternative hop drive), the collector (incorporated it into the armor/coating of the ship to be hooked to the jump drive and additional batteries if needed for extended jumping) and the point of origin (the GM was more interested in psionic power to play billiards with planets though) I looked into the 1st edition book of Psions and developed "black box psionic devices" also took a page or three from X4, stainless steal rats and developed minor background passive money making source for the adventures.

Condottiere: do you have a rough write-up of your "Venture type" systems or will they be in a future journal of traveller aid?

 

[Vormaerin]

1e Mongoose was rather notorious for not paying close attention to how things worked in the 40 years of previous material. Personally, I hate drop tanks and all the problems they cause, so they are not IMTU. That makes life a lot easier and I do have the fuel used slowly over time. I don't like the official power plant that sips their L-hyd for months of normal travel but then pulls a L-Hyd keg chug on jump.

But that's how it works officially for basically the entire history of the game. Its fine to say IMTU, I do this other thing. But if you have drop tanks, then the fuel has to be used up on jump. That's the only way they can work. The fuel has to be gone and the empty tanks jettisoned *before* jump or that volume counts against your jump capacity.

House rules are the norm at the table in this and most other games. But on the forums, its normally assumed you are talking about the official rules unless explicitly stated otherwise.

 

[Condottiere]

"Bulk Hauler (Oukhaha class): Oukhaha-class freighters are the backbone of many corporations in the Hierate. The Hauler consists of a central ‘drive spine’ to which cargo pods are attached using mechanical clamps. Fuel is stored in long fin-shaped tanks that can be collapsed and withdrawn into the central spine when empty, to make it easier for shuttles to access the cargo pods."(1st edition Mongoose Aslan)



Actually it was to be transferred to internal fuel tanks before being used in the "jump drive" but this design countered that because of "collapsible bladder tanks / i.e. drop tanks", and now in second edition mongoose we have power points instead so this should be moot where the fuel comes from because it is burned in the power-plant (i.e power points) and since were jumping with power points we can pull them from batteries, collectors, black globes, power-plants etc.. to be put in the jump drive compactors to "jump" (they originally exampled the Xboat jumping from batteries no fuel needed for jump).

In my ATU (trying to just bend and not to break the MTU RAW of 3I) there are high capacity batteries incorporated into the jump drive unit so effectively a ship in trouble could respinn up the the jump drive immediately and flee, since during the week in jump the batteries are being trickle charged. In the first edition I added extra fuel capacity for a Jump 1 for fleeing for that purpose mainly on military ships or scouts but it did make it on other ships because of ex-military/scouts personnel. In that game I also reversed engineered the annic nova (jump 2 and jump 3 drive = jump 6 if operational) black box jump drive (to develop a jump 9 ship via twin jump 3 drives when operational i.e a alternative hop drive), the collector (incorporated it into the armor/coating of the ship to be hooked to the jump drive and additional batteries if needed for extended jumping) and the point of origin (the GM was more interested in psionic power to play billiards with planets though) I looked into the 1st edition book of Psions and developed "black box psionic devices" also took a page or three from X4, stainless steal rats and developed minor background passive money making source for the adventures.

In theory, if you have two separate jump drives, you could take their collective tonnage, minus ten tonnes for overhead, for a greater factored jump, if both jump drives have the requisite technological level, and aren't customized/upgraded from a lower level. Not too familiar, or just can't recall, compatibility between the jump drives for the Annic Nova, so can't comment on actual feasability.

Condottiere: do you have a rough write-up of your "Venture type" systems or will they be in a future journal of traveller aid?

I considered having another go at submitting an article, this time for the XXSS-1 Venture, but suspect the lack of illustrations and deckplans will let it end up in the wastepaper basket.

I'm slowly working out the details on history and usage, but can't really promise any definite conclusion, since I've still haven't submitted the article on Vargr military organization for the past five years, I think.

 

[AnotherDilbert]

Actually it was to be transferred to internal fuel tanks before being used in the "jump drive" but this design countered that because of "collapsible bladder tanks / i.e. drop tanks",

Fuel from Drop tanks can be used directly, unlike Collapsible tanks.

So, as RogerD says, fuel from drop tanks has to be burned, and the tanks ejected, immediately before jump.

and now in second edition mongoose we have power points instead so this should be moot where the fuel comes from because it is burned in the power-plant (i.e power points) and since were jumping with power points we can pull them from batteries, collectors, black globes, power-plants etc.. to be put in the jump drive compactors to "jump" (they originally exampled the Xboat jumping from batteries no fuel needed for jump).

Note that you need power points AND lots of jump fuel to jump, copied from CT LBB5 (at least in the 2017 edition).


The original Xboat used jump fuel as usual, it just didn't have any power plant which was kind of logical in LBB2'77, as the jump drive burned the jump fuel without any involvement of the power plant (changed in LBB5'79 and LBB2'81).

CT S7, p10:
Express Boat (Type X): Constructed using the type 100 hull, the express boat is fitted with drives producing jump-4, and nothing else. There is no power plant or maneuver drive installation. Fuel tankage is forty tons, enough for one jump. The standard bridge is complemented by a Model14 computer, massive communicators, ...

 

[Subzero001]

Fuel from Drop tanks can be used directly, unlike Collapsible tanks.

So, as RogerD says, fuel from drop tanks has to be burned, and the tanks ejected, immediately before jump.



Note that you need power points AND lots of jump fuel to jump, copied from CT LBB5 (at least in the 2017 edition).


The original Xboat used jump fuel as usual, it just didn't have any power plant which was kind of logical in LBB2'77, as the jump drive burned the jump fuel without any involvement of the power plant (changed in LBB5'79 and LBB2'81).

Mongoose 2nd edition High Guard:
The express boat (x-boat) is the key to the Imperial communication network. The Scout Service maintains an extensive array of designated routes and supporting tenders to allow access to nearly every important system in the empire; the 100-ton xboat is the fast courier that carries data and messages between those points
The jump drive is powered by the battery, which is recharged during the normal refuelling operations. "Since it has fuel on board as well is it burned in the fusion power plant or just expelled and ignited to protect the ship in jump space "bubble" since things are "power points now" it doesn't state in 2nd edition."

Mongoose 2nd edition High Guard:
Drop Tank "dropped?"
Hundreds of Gazelle-class close escorts have been built and many remain in service in the Imperial Navy, despite the fact that in a combat situation, they are nearly worthless. The close escort, even when new, was not intended to stand up to combat vessels; rather it was envisioned as an antipiracy and revenue patrol ship. In that role, it has performed well, but when pressed into combat duties it has invariably suffered disproportionate losses
With the internal tankage Jump-3 can be achieved, with drop tanks Jump-5 "fuel transferred to internal tanks or burned in the fusion power plant or just expelled and ignited to protect the ship in jump space "bubble" since things are "power points now" it doesn't state in 2nd edition", with the drop tanks retained Jump-4. so they can be retained and not needed to be dropped it seems. "yes, it does affect the jump max though"

Now with older systems that are not "converted to power points" your millage will differ. I am not trying to rehash, but just state RAW MTU as stated and read.

This question was originally on the "In Mongoose Traveller" or MTU so I kept it to MTU 1st and 2nd ed, I am reading 2022's version now to see if there is any differences. I also added some T5 since that is where mongoose received its modifications from but T5 is a mess and not really playable out of the box. Thanks for the input/incite, Have a good weekend.

 

[Condottiere]

I checked the current entry of drop tanks, and it's not mentioned where the flow goes.

In theory, for the power plant, you only need one tonne fuel tank onboard.

 

[AnotherDilbert]

Mongoose 2nd edition High Guard:
...
The jump drive is powered by the battery, which is recharged during the normal refuelling operations. "Since it has fuel on board as well is it burned in the fusion power plant or just expelled and ignited to protect the ship in jump space "bubble" since things are "power points now" it doesn't state in 2nd edition."

Agreed, in MgT2 HG it is not defined which machine burns the jump fuel, but it is needed. MgT2 is very deliberately vague on the technical details, but is generally supposed to be compatible with T5, so I would look there for explanations, i.e. I would assume the PP burns the jump fuel. Or look in the JTAS Jumpspace article quoted below.

Mongoose 2nd edition High Guard:
Drop Tank "dropped?"
...
With the internal tankage Jump-3 can be achieved, with drop tanks Jump-5 "fuel transferred to internal tanks or burned in the fusion power plant or just expelled and ignited to protect the ship in jump space "bubble" since things are "power points now" it doesn't state in 2nd edition", with the drop tanks retained Jump-4. so they can be retained and not needed to be dropped it seems. "yes, it does affect the jump max though"

Yes, of course they can be dropped or retained, as in all previous editions. Whether dropped or retained, no extra internal fuel tankage is required: the fuel is used directly from the drop tank, that can be ejected before jump, so the fuel is burned quickly before jump.

Just like in LBB5'80 you need power AND jump fuel to jump, the required power does not replace the jump fuel, it's just "priming the pump".

Ye olde JTAS article was reprinted verbatim in Mongoose JTAS:

JTAS volume 2, Jumpspace, p126:
When the jump drive is activated, a large store of fuel is fed through the ship’s power plant to create the energy necessary for the jump drive. In the interests of rapid energy generation, the power plant does not work at full efficiency and some of the fuel is lost in carrying off fusion by-products and in cooling the system. At the end of a very brief period (less than a few minutes), the jump drive capacitors have been charged to capacity. Under computer control, the energy is then fed into appropriate sections of the jump drive and jump begins.

 

[Condottiere]

When you consider the original lanthanum grid, and the new localized field, in case of breaks, nobody knows.

 

[Sigtrygg]

I want to make sure I have this right: the hydrogen is used to make a bubble around the ship while it is in jump space. And that hydrogen comes back into normal space and does not stay in jump space......So why does the amount of hydrogen needed depend on the distance travelled? After all, it always takes a week whether the ship jumps 1 or 3 parsecs. Given the above, the amount of hydrogen needed should only depend on the displacement tonnage of the ship?

No.
There is no hydrogen filled bubble. It is an error introduced in T4 due to misreading/misunderstanding the MegaTraveller Starship Operator's Manual. It has been removed from T5.

Collector powered jump drives and antimatter powered jump drives don't use hydrogen.