Ships blowing up in combat
- Thread starter ochd
- Start date
I'm sure you could arbitrarily decide a point where something is battered to bits by hits; it's usually sufficient that something is inoperable, so that's as low as the damage results go.
I (and my group) prefer that things don't actually just explode like a movie or something - for something to explode, it needs an explosive. In movies, that's provided by gasoline, actual explosives, or CG. In real life, things don't actually explode like in movies, unless it's like a barge transporting flour where the flour dust explodes or something similar. Even in combat, like WW1 or WW2, a ship may be described as "exploding" but then it is followed by "and broke in half and sunk" or something similar; it's why wrecks of ships from those wars can still be found in large pieces. In space, there's no water for the ships to conveniently disappear in, so even if there is an explosion, the majority of the ship remains intact but the ship is still a dead hulk at that point.
I (and my group) prefer that things don't actually just explode like a movie or something - for something to explode, it needs an explosive. In movies, that's provided by gasoline, actual explosives, or CG. In real life, things don't actually explode like in movies, unless it's like a barge transporting flour where the flour dust explodes or something similar. Even in combat, like WW1 or WW2, a ship may be described as "exploding" but then it is followed by "and broke in half and sunk" or something similar; it's why wrecks of ships from those wars can still be found in large pieces. In space, there's no water for the ships to conveniently disappear in, so even if there is an explosion, the majority of the ship remains intact but the ship is still a dead hulk at that point.
Thanks Epicenter. Makes sense.
What if, say, a couple of missiles hit a 40 ton pinnace, doing 40 damage. Under the rules as written, as I understand them, the pinnace is totally inoperable and beyond repair. It would suffer 10 severity 1 critical hits, which might lead to people on board taking damage, but chances are, while the ship is a wreck, everyone on board will be otherwise unharmed, particularly if they are wearing TL12 vacc suits or something else with good protection and life support.
Would it be more realistic to rule that the ship has been completely destroyed and all people on board killed?
Cheers,
Dan.
What if, say, a couple of missiles hit a 40 ton pinnace, doing 40 damage. Under the rules as written, as I understand them, the pinnace is totally inoperable and beyond repair. It would suffer 10 severity 1 critical hits, which might lead to people on board taking damage, but chances are, while the ship is a wreck, everyone on board will be otherwise unharmed, particularly if they are wearing TL12 vacc suits or something else with good protection and life support.
Would it be more realistic to rule that the ship has been completely destroyed and all people on board killed?
Cheers,
Dan.
You could do what the rules say for animals (Core rulebook page 80). Dead at 0 Hits, totally destroyed at a number of negative hits equal to their normal total. So if an animal has 10 hits, it dies a 0 Hits (but meat/hide can be harvested) and is totally destroyed at -10 Hits (being nearly worthless).
Likewise you could say a ship with 40 Hull is destroyed at 0 Hull (but can still have parts salvaged), and is totally destroyed at -40 (nothing usable left).
Likewise you could say a ship with 40 Hull is destroyed at 0 Hull (but can still have parts salvaged), and is totally destroyed at -40 (nothing usable left).
There's nothing wrong with a ship blowing up, per se, but you need to determine what exactly is blowing up. A hit on a magazine (or even a turret) can cause sympathetic explosions of stored ammunition. You could also possibly have a piercing hit from a weapon that detonates the hydrogen fuel stored in a fuel tank (combining with the oxygen atmosphere of the inside... by itself hydrogen in space won't explode).
steve98052
Mongoose
I think a "ship explodes" result would be appropriate in some cases involving huge overkill damage in a single hit. A spinal weapon hit from a battleship might be enough to turn an entire fighter into plasma. A high velocity collision between ships of similar mass would turn everything in the direct hit zone to incandescent vapor, possibly with enough excess energy to melt the rest. A sublight starship hitting anything substantial near top speed could vaporize it. And a starship sized object hitting a planet after a month or more of acceleration in a single direction might be able to shatter a planet. (That last point is one customarily handwaved as abuse of physics, lest it lead to an insoluble debate.)
The rules are really only meant to describe what it takes to make a ship less functional, damaged within reach of combat repairs, damaged within reach of careful field repairs, damaged requiring shipyard repairs, or damaged beyond repair. Blasted to chunks, confetti, molten spray, vaporized, or glowing plasma are better suited to physics calculations than readings of the rules. Some editions of Traveller give weapons power in physical units; in those versions you can work out the math: how many tons of iron can be heated from the temperature of liquid hydrogen to iron's boiling point by one Tera joule, for example. Or calculate how much liquid hydrogen can one Tera joule heat to a point where most of it is ionized (because instantly going from liquid to plasma is a lot of explosive force).
The rules are really only meant to describe what it takes to make a ship less functional, damaged within reach of combat repairs, damaged within reach of careful field repairs, damaged requiring shipyard repairs, or damaged beyond repair. Blasted to chunks, confetti, molten spray, vaporized, or glowing plasma are better suited to physics calculations than readings of the rules. Some editions of Traveller give weapons power in physical units; in those versions you can work out the math: how many tons of iron can be heated from the temperature of liquid hydrogen to iron's boiling point by one Tera joule, for example. Or calculate how much liquid hydrogen can one Tera joule heat to a point where most of it is ionized (because instantly going from liquid to plasma is a lot of explosive force).
Condottiere
Emperor Mongoose
I miss fusion bottles going rogue.
Exactly. If a ship takes a multiple hit to an internal location which is likely to explode (power plant) then I think it's quite realistic that it might blow up.
And whilst hitting a fighter with a spinal mount may be unlikely, hitting it with a bay-mounted anti-capital ship weapon ten times its size is pretty close. Hell, running into a torpedo at orbital velocity is going to leave rather less than a "disabled wreck".
But ultimately, it's for the GM to determine. Whether a destroyed ship drifts off, breaks up, or blows up is largely a narrative decision by him, and only really affects matters if the PCs are either (1) on board, (2) docked to it because they're trying to board it or (3) wanted to loot it.
And whilst hitting a fighter with a spinal mount may be unlikely, hitting it with a bay-mounted anti-capital ship weapon ten times its size is pretty close. Hell, running into a torpedo at orbital velocity is going to leave rather less than a "disabled wreck".
But ultimately, it's for the GM to determine. Whether a destroyed ship drifts off, breaks up, or blows up is largely a narrative decision by him, and only really affects matters if the PCs are either (1) on board, (2) docked to it because they're trying to board it or (3) wanted to loot it.
steve98052
Mongoose
Doing a little research and math, I find that:
A. Each 1 GJ of energy turns about 2 tons of liquid hydrogen to gas.
B. Each 1 MJ raises the temperature of 1 ton of hydrogen gas about 70K (degrees Kelvin), so 1 GJ would raise 1 ton to around 70kK (70 thousand degrees Kelvin), except that it dissociates and ionizes before reaching that temperature.
C. It takes 436 J to dissociate 2 grams of normal hydrogen gas to atomic hydrogen, so 218 J/g, 218 kJ/kg, 218 MJ/ton, or about 1 GJ/5 tons.
D. It takes 1312 KJ per gram to ionize atomic hydrogen, so 1312 MJ per kg about 1 GJ/(3/4 ton) to completely ionize, but it takes on the characteristics of a plasma before it is completely ionized.
I wasn't able to find how hot ordinary hydrogen gets before dissociating to atomic hydrogen, or how hot atomic hydrogen gets before turning into a plasma. But the surface of the Sun is about 5800K, and it's a plasma, so I'll guess that if we start with 1 ton of liquid hydrogen:
A. About 0.5 GJ turns liquid to gas.
B. About 0.1 GJ heats gas to 7000K.
C. About 0.2 GJ dissociates ordinary gas to atomic hydrogen.
D. About 1.3 GJ turns atomic hydrogen to completely ionized plasma.
Based on that, a total of 2.1 GJ turns liquid hydrogen to completely ionized plasma, so 2 GJ turns it to mostly-ionized plasma. A GURPS Traveller meson gun bay delivers almost 13 GJ of energy, which turns over 6 tons of liquid hydrogen to plasma, assuming it delivers all of its energy to the fuel tank.
I don't know how much damage it would cause to suddenly turn six tons of liquid hydrogen to plasma, but it doesn't sound like it would be good for the targeted ship.
Putting energy into other units, 4 TJ is not quite 1 kiloton of TNT equivalent, and 4000 TJ is not quite 1 megaton TNT equivalent. A 1 kiloton nuclear weapon is a small tactical warhead, the Hiroshima and Nagasaki bombs were about 15 and 20 kilotons respectively, and the largest thermonuclear bomb ever was 57 megatons. Weapons measured in Terajoules can ruin your day even if you're in a capital ship.
(All "tons" here refer to tonnes.)
A. Each 1 GJ of energy turns about 2 tons of liquid hydrogen to gas.
B. Each 1 MJ raises the temperature of 1 ton of hydrogen gas about 70K (degrees Kelvin), so 1 GJ would raise 1 ton to around 70kK (70 thousand degrees Kelvin), except that it dissociates and ionizes before reaching that temperature.
C. It takes 436 J to dissociate 2 grams of normal hydrogen gas to atomic hydrogen, so 218 J/g, 218 kJ/kg, 218 MJ/ton, or about 1 GJ/5 tons.
D. It takes 1312 KJ per gram to ionize atomic hydrogen, so 1312 MJ per kg about 1 GJ/(3/4 ton) to completely ionize, but it takes on the characteristics of a plasma before it is completely ionized.
I wasn't able to find how hot ordinary hydrogen gets before dissociating to atomic hydrogen, or how hot atomic hydrogen gets before turning into a plasma. But the surface of the Sun is about 5800K, and it's a plasma, so I'll guess that if we start with 1 ton of liquid hydrogen:
A. About 0.5 GJ turns liquid to gas.
B. About 0.1 GJ heats gas to 7000K.
C. About 0.2 GJ dissociates ordinary gas to atomic hydrogen.
D. About 1.3 GJ turns atomic hydrogen to completely ionized plasma.
Based on that, a total of 2.1 GJ turns liquid hydrogen to completely ionized plasma, so 2 GJ turns it to mostly-ionized plasma. A GURPS Traveller meson gun bay delivers almost 13 GJ of energy, which turns over 6 tons of liquid hydrogen to plasma, assuming it delivers all of its energy to the fuel tank.
I don't know how much damage it would cause to suddenly turn six tons of liquid hydrogen to plasma, but it doesn't sound like it would be good for the targeted ship.
Putting energy into other units, 4 TJ is not quite 1 kiloton of TNT equivalent, and 4000 TJ is not quite 1 megaton TNT equivalent. A 1 kiloton nuclear weapon is a small tactical warhead, the Hiroshima and Nagasaki bombs were about 15 and 20 kilotons respectively, and the largest thermonuclear bomb ever was 57 megatons. Weapons measured in Terajoules can ruin your day even if you're in a capital ship.
(All "tons" here refer to tonnes.)
Jeraa said:
Hey, I like this idea as a quick guide, thanks -- with the provisos others have added about the nature of that destruction, etc. On the explosion thing, missiles (as in my previous example) have explosive warheads, right? And therefore on impact there will be explosion(s) (if not necessarily the entire pinnace, Star Wars style)? Sorry for the dumb questions; the humanities are more my thing.
Dan.
steve98052
Mongoose
Yes, Traveller ship missiles generally have explosive warheads. But at longer range, they'll do more damage if they're targeted as kinetic weapons. Three turns at 6 G acceleration (20 minutes × 60 × seconds per minute × 9.8 m/s^2 = 72 km/s) is on the order of 300 GJ, or around 70 tons of TNT equivalent, for a 70 kg missile -- roughly 1000 times as powerful as if the entire missile were made of high explosive.ochd said:
So, if your missile is on target for a direct hit, you'll do much better by telling the missile not to detonate; although the shrapnel will still hit the target, it will be diffused over a larger area, instead of concentrated into a 25 cm hole. At 72 km/s, even shrapnel fragments propelled directly away from the target will hit, because a high explosive blast peaks out around 8 km/s.
In fact, I think a kinetic hit is better than a proximity explosion in almost every case except where the missile has to run a wild chase to catch the target. Except to give the missile an extra chance at doing damage even if it's hit by point defense fire, it would actually be better to replace the entire warhead by increased acceleration capacity.
