An Alternative Fuel Hit Rule

[kilemall]

While working out the new damage table from my system, I got to thinking about what the ships are actually engineered like.


One of the factors clear from at least CT/HG was that fuel tanks wrap around the ship and act as ersatz armor/damage sinks.


That makes sense, and also of course the hydrogen fuel can act as an extra radiation shield.


So when I got to radiation hits, it occurred to me that the various rads hitting the fuel tanks would be hitting that fuel skin/shield pretty hard.


I could just rule it loses fuel, but thought of a more interesting result.


Instead of fuel lost, the fuel is 'contaminated' by the radiation, causing all sorts of impurities, with the result that the fuel is no longer considered refined.


Thus, it cannot be used for jumps without risking misjump and has to be repurified. Or worse, ships without onboard purifiers have to go back and get refined fuel.

 

[aramis]

Instead of fuel lost, the fuel is 'contaminated' by the radiation, causing all sorts of impurities, with the result that the fuel is no longer considered refined.


Thus, it cannot be used for jumps without risking misjump and has to be repurified. Or worse, ships without onboard purifiers have to go back and get refined fuel.

Given...

1. the fuel used is some isotope of hydrogen, possibly already contaminated with methane, ammonia, helium, and other isotopes of hydrogen.
2. The intended use generates far more radiation than any weapon hit, save potentially meson gun hits; if radiation were a factor, the fuel would self-contaminate before hitting the ignition chamber.
3. the energies needed to make a contaminant that matters essentially involve alterations of the atomic structure - either triggering neutron decay, proton decay, proton capture, or neutron capture.
4. the only weapons below TL16 with sufficient energy density capability to accomplish #4 are meson guns, and probably not at ship-combat ranges...

It's far less of a stretch to simply have it shatter it's tanks from thermal shock and decompression forces.

 

[kilemall]

Given...

1. the fuel used is some isotope of hydrogen, possibly already contaminated with methane, ammonia, helium, and other isotopes of hydrogen.
2. The intended use generates far more radiation than any weapon hit, save potentially meson gun hits; if radiation were a factor, the fuel would self-contaminate before hitting the ignition chamber.
3. the energies needed to make a contaminant that matters essentially involve alterations of the atomic structure - either triggering neutron decay, proton decay, proton capture, or neutron capture.
4. the only weapons below TL16 with sufficient energy density capability to accomplish #4 are meson guns, and probably not at ship-combat ranges...

It's far less of a stretch to simply have it shatter it's tanks from thermal shock and decompression forces.

On point #1, isn't the point of refined fuel to eliminate all contaminants and have a purer fuel that apparently affects jump safety? Unrefined sure, but not the refined stuff.



On point #2, I'm not dealing with the fusion reactor, but the jump drive, where the game consequence is the misjump effects.

Even if jump is partially some massive high-speed fusion event, it clearly isn't affected by radiation per se. I'm more focused on ionization 'contaminating' the input fuel to jump rather then radiation itself being problematic.

On point #3, I thought that was rather clear. If not, yes of course it would be some sort of ionization/transmutation event.

On point 4, PA weapons apparently are hitting with enough force to do damage to hardware and equipment, I would presume the accompanying proton showers or whatever else it is is way beyond the modern day research accelerator in order to do the damage postulated and so too would the accompanying ionization.

Or, they could actually be grasers.


I'm not wed to this concept, and just garden variety fuel tank effects from embrittlement or whatnot may be more reasonable, I am interested in hearing about whether it's an interesting game effect rule in addition to the science/psuedoengineering.

 

[aramis]

On point #1, isn't the point of refined fuel to eliminate all contaminants and have a purer fuel that apparently affects jump safety? Unrefined sure, but not the refined stuff.



On point #2, I'm not dealing with the fusion reactor, but the jump drive, where the game consequence is the misjump effects.

Even if jump is partially some massive high-speed fusion event, it clearly isn't affected by radiation per se. I'm more focused on ionization 'contaminating' the input fuel to jump rather then radiation itself being problematic.

On point #3, I thought that was rather clear. If not, yes of course it would be some sort of ionization/transmutation event.

On point 4, PA weapons apparently are hitting with enough force to do damage to hardware and equipment, I would presume the accompanying proton showers or whatever else it is is way beyond the modern day research accelerator in order to do the damage postulated and so too would the accompanying ionization.

Or, they could actually be grasers.


I'm not wed to this concept, and just garden variety fuel tank effects from embrittlement or whatnot may be more reasonable, I am interested in hearing about whether it's an interesting game effect rule in addition to the science/psuedoengineering.

Ionizing radiation sufficient to change the atomic numbers of the low end — Carbon and below on the periodic table — is sufficient to dissociate the metal holding it, too. Not something one can readily do, even with a fusion gun. And the PA is going to do that to the container FIRST, at which point, the fuel has found and/or makes a new vent.

Canonically, J-Fuel is fused in use — fast and without the safety gear of a PP — the exhaust is helium, lithium, beryllium, boron, carbon... and a few traces of nitrogen, oxygen, fluorine, and neon. Ionization is the first step in fusion - raising it to a plasma is in fact ionization. Ionizing it early won't have much effect.

Likewise, it's not going to take much at all to fry computers. An EMP capable of shutting down your car won't even make you notice it, aside from literally frying the computer controlling the engine. (Unless you happen to be grounded and holding a metal object), Many orders of magnitude less energy than altering the atomic numbers of the involved. At least for the ones being developed for the army. (Why does the Army want them? Stopping incoming vehicles which fail to slow when told - many of which later go "BOOM" thanks to the other contents. Preventing)

So, unless you're changing the nature of the fuel, radiation hits doing anything other than heating it up and forcing the overpressure vent to trigger and/or making a new one of its own device...

 

[kilemall]

Pffft. I'm interested in whether it's an interesting GAME effect.

 

[mike wightman]

You mean stuff physics, let's just use terms that sound cool and to hell with the science in science fiction?

This is Traveller not Star Wars

Nuclear radiation - particles and electromagnetic waves given off by the nucleus of an atom.

Ionizing radiation - radiation (particulate and electromagnetic wave) that knocks electrons off atoms and molecules and thus ionizing them.

There is considerable overlap between the two terms since most nuclear radiation will ionize atoms and molecules.

To change the nucleus of an atom of the material the particle beam strikes does not require ionization, it requires some form of nuclear reaction - fusion, fission, neutron capture, neutron decay, alpha decay etc.

If you want to understand the affects of PA weapons on materials I would recommend starting with the Atomic Rockets article on the subject:
http://www.projectrho.com/public_html/rocket/spacegunconvent.php#id--Particle_Beams

 

[Ulsyus]

Likewise, it's not going to take much at all to fry computers. An EMP capable of shutting down your car won't even make you notice it, aside from literally frying the computer controlling the engine. (Unless you happen to be grounded and holding a metal object), Many orders of magnitude less energy than altering the atomic numbers of the involved. At least for the ones being developed for the army. (Why does the Army want them? Stopping incoming vehicles which fail to slow when told - many of which later go "BOOM" thanks to the other contents. Preventing)

There are some far far simpler low-tech means of achieving the same outcome that could be implemented now, but I get how you got to the example in the discussion.

I thought the idea of using fuel as ersatz armour is quite sensible, but that would require a change in hit locations with ships to reflect that design principle. Following on from that, it could be a design philosophy followed by a particular designer but not the 3I

 

[AnotherDilbert]

Letting fuel count as armour is a rather obvious idea, on the principle that any weapon hitting the fuel will waste its energy without doing any significant damage.


I experimented with letting each 5% of the ship that was fuel count as 1 armour, even against mesons. Suddenly warships really wanted to carry a lot of fuel, so battle riders were out and battleships were in. The Fighting Ships designs worked much better. Combat became slow attrition... That is at least what I recall, it was quite a while ago.

 

[mike wightman]

Bespoke hit location tables and/or a re-jig of the surface explosion table in HG perhaps?

 

[sabredog]

Pffft. I'm interested in whether it's an interesting GAME effect.

What about the effect of slushy frozen L-Hyd sloshing out into the ship's interior when a multi-megawatt laser punches through the tanks? Or multiple explosive hits from a missile blasting the L-Hyd into someone's stateroom or other spaces?

I would imagine that'd provide some interesting game effects.

 

[kilemall]

What about the effect of slushy frozen L-Hyd sloshing out into the ship's interior when a multi-megawatt laser punches through the tanks? Or multiple explosive hits from a missile blasting the L-Hyd into someone's stateroom or other spaces?

I would imagine that'd provide some interesting game effects.

Arguably that should be happening now.


Exhibit A, the Type S, about half of the back end of the wedge is fuel tank an by the deck plan the stuff should be making a mess on every fuel loss hit.

 

[kilemall]

Bespoke hit location tables and/or a re-jig of the surface explosion table in HG perhaps?

I was working backwards FROM the HG surface table, imagining what layout creates those hit probabilities.

In those tables, armor initially protects against internal/critical hits, then at higher levels reduces the threat to weapons and maneuver drives, ultimately smaller and smaller hits against fuel.

To me that suggests a double hulled ship more like a sub with the fuel tanks and weapons mounted between the outer and inner hulls. The heavier armor would be assigned to the inner 'pressure' hull protecting the critical innards and the highest total levels meaning more armor on the exterior hull.

Sort of a spacegoing Standard system of armor protection-
https://en.wikipedia.org/wiki/All_or_nothing_(armor)


Considering the radiation shielding role was actually an afterthought to the above, kind of a bonus to what the fuel placement was doing anyway.

As part of my reimagining of HG, I was trying to consider having different hull armor arrangements, with heavy bulkheading to limit meson gun effects (nautilus shell), thick exterior/thin bulkheading (the hard exterior/chewy center system), and increased per system armor (so magazines and capacitors get the most, power plants life support and computers get next best, etc.).

Ended up throwing away the damage tables, but was a good exercise in naval engineering re: effective design.

 

[sabredog]

Arguably that should be happening now.


Exhibit A, the Type S, about half of the back end of the wedge is fuel tank an by the deck plan the stuff should be making a mess on every fuel loss hit.

It may be off-topic then, but I was just looking at that as a realistic "interesting effect" that I've never seen addressed before. The loss of fuel in bulk is covered, but not the damage that would be from the interior spill. If that hit a crew member, even in a suit, it would be catastrophic.

So I was just wondering if anyone here had factored that in. I have tried before but with mixed results and requiring tracing the hit through the section rolled as damaged on the ship plans. Similar to how I figure possible crew hits when they are in sections hit.

 

[whartung]

How many Joules of energy can a freezing mass of LHyd absorb?

If a laser (ship-to-ship laser) burns in to a full tank, how much hydrogen is converted in to gas, if that tank is full, how is that gas vented (or is LHyd squirted out the "nose" of the tank)?

If you pull a few dTons of fuel off the tank, to leave a gap - hows does that change the dynamics of it?

Does a big gas bubble just form and gurgle up to the top? (or just expand LHyd to the space in the "top" of the tank in zero-g, since the bubble doesn't actually rise.)

Maybe standard combat ops is to vent fuel (transfer fuel) to make sure no tanks are "full" less they potentially rupture from a laser hit. Ensure that they all have some room for expansion.

Mind, I don't know how a partially full LHyd tank behaves at all.

 

[Whipsnade]

It may be off-topic then, but I was just looking at that as a realistic "interesting effect" that I've never seen addressed before.

It hasn't been "addressed" for much the same reason the "interesting effect" of lasers more easily blinding people than wounding or killing hasn't been "addressed".

It's an interesting fact whose effects on ship combat are not worth the rules needed to apply it.

 

[kilemall]

You mean stuff physics, let's just use terms that sound cool and to hell with the science in science fiction?

This is Traveller not Star Wars

Nuclear radiation - particles and electromagnetic waves given off by the nucleus of an atom.

Ionizing radiation - radiation (particulate and electromagnetic wave) that knocks electrons off atoms and molecules and thus ionizing them.

There is considerable overlap between the two terms since most nuclear radiation will ionize atoms and molecules.

To change the nucleus of an atom of the material the particle beam strikes does not require ionization, it requires some form of nuclear reaction - fusion, fission, neutron capture, neutron decay, alpha decay etc.

If you want to understand the affects of PA weapons on materials I would recommend starting with the Atomic Rockets article on the subject:
http://www.projectrho.com/public_html/rocket/spacegunconvent.php#id--Particle_Beams

Ya I read it before starting this, but if we go hardcore Atomic Rockets a LOT of Traveller breaks. That's why I'm good with 'sounds good/plausibility' rather then ending up going the George Meson retcon route. Bleh.


Anyway, what the PA beam does to the fuel is only the first half of the handwavium. The second part is what exactly is refined fuel.

 

[kilemall]

How many Joules of energy can a freezing mass of LHyd absorb?

If a laser (ship-to-ship laser) burns in to a full tank, how much hydrogen is converted in to gas, if that tank is full, how is that gas vented (or is LHyd squirted out the "nose" of the tank)?

If you pull a few dTons of fuel off the tank, to leave a gap - hows does that change the dynamics of it?

Does a big gas bubble just form and gurgle up to the top? (or just expand LHyd to the space in the "top" of the tank in zero-g, since the bubble doesn't actually rise.)

Maybe standard combat ops is to vent fuel (transfer fuel) to make sure no tanks are "full" less they potentially rupture from a laser hit. Ensure that they all have some room for expansion.

Mind, I don't know how a partially full LHyd tank behaves at all.

Well I know one thing. You want to depressurize cause you don't want L-Hyd mixing with oxygen and sparks, a likely combination in combat, and you don't want to re-pressurize until it's cleaned up.


https://en.wikipedia.org/wiki/Hydrogen_safety

 

[kilemall]

It hasn't been "addressed" for much the same reason the "interesting effect" of lasers more easily blinding people than wounding or killing hasn't been "addressed".

It's an interesting fact whose effects on ship combat are not worth the rules needed to apply it.

Everything we are talking about in this thread should be viewed through this lens.

 

[Ulsyus]

Exhibit A, the Type S, about half of the back end of the wedge is fuel tank an by the deck plan the stuff should be making a mess on every fuel loss hit.

What if the tank that contains it is overpressured so that an external hull breach causes it to vent away from the fleshy passengers? What about using a grav-based system to force venting away from the inner hull?

How many Joules of energy can a freezing mass of LHyd absorb?

If a laser (ship-to-ship laser) burns in to a full tank, how much hydrogen is converted in to gas, if that tank is full, how is that gas vented (or is LHyd squirted out the "nose" of the tank)?

Could it vent out of the hole htat has just been burnt in the hull itself?

If you pull a few dTons of fuel off the tank, to leave a gap - hows does that change the dynamics of it?

Does a big gas bubble just form and gurgle up to the top? (or just expand LHyd to the space in the "top" of the tank in zero-g, since the bubble doesn't actually rise.)

Does a big gas bubble just form and gurgle up to the top? (or just expand LHyd to the space in the "top" of the tank in zero-g, since the bubble doesn't actually rise.)

If the gap is vacuum then how is the fuel normally drawn out of the tank? Is the tank made up of multiple smaller tanks and each is drained in sequence (or serially from different parts of the hull to maintain an equal distribution of mass IOT prevent destabilised flight)? If the gap is vacuum then that could that contain some of the explosive combustion of LHyd that would occur when hit by a laser or missile warhead?

Maybe standard combat ops is to vent fuel (transfer fuel) to make sure no tanks are "full" less they potentially rupture from a laser hit. Ensure that they all have some room for expansion.

Mind, I don't know how a partially full LHyd tank behaves at all.

If a "fuel tank" was made up of numerous smaller tanks then that would be a simpler exercise to go through. It could also mean that any one hit wouldn't cause a catastrophic loss of fuel for a vessel.

 

[whartung]

It hasn't been "addressed" for much the same reason the "interesting effect" of lasers more easily blinding people than wounding or killing hasn't been "addressed".

Chadwick wrote somewhere that the blinding effect of lasers was specifically not addressed. They thought about it, and chose not to bring it up at all.