How resiliant is Wars armor?

[adam_grif]

I knew nukes could be that small, I just didn't know you could squeeze 1 MT into such a small package

[Connor MacLeod]

Well the Communications Ship was something of a particular case - its hangar bays were particularly large IIRC and the reactor was exposed to direct attack therefrom!

But they were going after the "main power tree" or something like that. I know Curtis has alluded to this on his site as part of ship design. Basically there's no possible way to effectively armor the power transfer systems with hangars like that, so its a point of potential vulnerability even if we don't include the possibility of volatiles on deck or anything like that.

[adam_grif]

Well the Communications Ship was something of a particular case - its hangar bays were particularly large IIRC and the reactor was exposed to direct attack therefrom!

But they were going after the "main power tree" or something like that. I know Curtis has alluded to this on his site as part of ship design. Basically there's no possible way to effectively armor the power transfer systems with hangars like that, so its a point of potential vulnerability even if we don't include the possibility of volatiles on deck or anything like that.

So does this vulnerability exist in all SD type ships, all ships with big hangars like that, or what? And again, is a 1 MT blast sufficient for setting off a chain reaction like this?

[Marko Dash]

even if the ship itself could shrug it off its likely to kill a fair bit of the crew. if it goes of in some hallway, and the walls, floor, etc. can take it you now have the blast being channeled through the ship unable to dissipate as much as it would in open air.

despite how much the ship can take the squishes that populate it aren't as though. i wonder if the blast doors could stand that kind of pressure wave?

i don't really know how a nuke would react in a confined space, did any of the underground tests determine how the pressure wave travels down tunnels?

[recon20011]

So does this vulnerability exist in all SD type ships, all ships with big hangars like that, or what? And again, is a 1 MT blast sufficient for setting off a chain reaction like this?

As someone said earlier, all vessels with hangar bays have a major vulnerability to explosions. So the size of the blast insn't really too relevant. At Midway the Japanese carrier Akagi was hit once. One bomb.

Akagi was hit by just one bomb, which penetrated to the upper hangar deck and exploded among the armed and fueled aircraft there.

That one bomb (yield unknown but it was a conventional armor-piercing bomb) caused enough damage to be done to the Akagi (260m length, not that you can really compare that to a starship) that it was scuttled. My point is, there really is no limit to the amount of damage done when a bomb explodes on a hangar deck. The limiting factor is simply the amount of fuel and ammunition stored in that portion of the ship and not the size of the original bomb.

[Darksider]

That's always been my own personal theory on how rebel fighters have been able to take down ISDs on those occasions they have been shown do do so but the exact events aren't stated (IE: game missions.) They didn't do it by blowing the "shield generators," They did it by chucking bombs into the hanger bays.

[adam_grif]

How large is an ISD hangar bay anyway?

[DrStrangelove]

How large is an ISD hangar bay anyway?

Big enough to comfortably fit a 125-50m CR90 corvette

[recon20011]

Just out of curiosity, does anyone know how many fighters (presumably TIEs) would be stored and rearmed in an ISD hangar bay? Because that might help give an indication of the amount of stores (fuel and ammunition) that would exposed during refueling/rearming operations and could possibly give an idea of the amount of damage a bomb/torpedo exploding on the hangar deck could do.

[Srelex]

Just out of curiosity, does anyone know how many fighters (presumably TIEs) would be stored and rearmed in an ISD hangar bay? Because that might help give an indication of the amount of stores (fuel and ammunition) that would exposed during refueling/rearming operations and could possibly give an idea of the amount of damage a bomb/torpedo exploding on the hangar deck could do.

According to the states, an ISD can carry 48 TIE fighters; apparently, other bombers and landing craft are included there too: http://starwars.wikia.com/wiki/Imperial ... _Destroyer

[recon20011]

So approximately 72 fighters and bombers. I see no indication that there are any completely separate hangar bays. All branch off from the main one. So the possible explosion would be quite big, considering it has access to 72 fighters' worth of fuel and ordnance. Bigger than I originally thought, I didn't think that the design would have placed all the eggs in one basket, so to speak.

[Sea Skimmer]

ICS shows the hanger deck subdivided by squadron hangers but with no obvious rear door. It also specifically states that TIE bombers are kept in armored compartments to control damage if the bombs go off. Given the size of an ISD they really should be able to have enough armor and void space to completely isolate the hanger deck even if that occurs. The ICS does show a thicker then normal bulkhead around the hanger deck.

The open rears in each hanger bay would make them pretty vulnerable to a mass fire-explosion in the fighter group, it’s a glaring vulnerability but it shouldn’t be fatal because explosive blast can simply vent right into the vacuum of space. That’s an enormous advantage. That 14.7psi of air pressure we have on earth does quite a lot to tamp blasts.

So no real excuse exists for why the hanger decks make ISDs blow up from such trivial attacks. They must just have incredibly sloppy munitions handling arrangements that allow explosions to get through open doors in the armor envelope. Then a chain reaction could explode the main magazines and via that explode the reactor and destroy the ship. Its really hard to believe that the armor on the hanger deck just fails.

Its worth looking at what went right on Akagi as an excellent example, her armor deck completely defeated the blasts from dozens of her own air group weapons. The American 1000lb bomb could not physically have defeated it either; a GP bomb of the class will just break up striking an 80mm thick armor deck. Shipboard power failed for a period but the machinery was not damaged except the rudder, which was jammed by a bomb exploding in the water. She remained underway for some hours after the attack. The ship did not sink and showed no signs of doing so even tweleve hours after her abandonment. Three Japanese destroyers had to put torpedoes into her to sink her.

USS Franklin survived similar damage, though with most bombs exploding on the flight deck (main reason she wasn't lost) and 724 men killed. Like Akagi the machinery and main magazines were not affected except by smoke. Since a warship in space can’t sink, they really should be absurdly tough to destroy. I mean we need not forget the Russian battleship Marat which had an entire main magazine blown up, demolishing the entire bow, but then had her stern raised from the harbor and returned to action as a gun battery.

Damage diagram for USS Franklin 1945 bombing damage
http://www.researcheratlarge.com/Ships/ ... Plate2.jpg

[recon20011]

Agreed, the Akagi wasn't sunk by the explosions, but she was crippled enough that she wasn't considered worth salvaging, and for a fleet that had just lost half their carrier strength that is saying something.
And also, the Akagi was hit during flight operations, namely, there was ordnance lying around everywhere, fuel lines trailing everywhere, etc. To facilitate those operations many bulkheads that were normally closed during combat (because all the aircraft are supposed to be away defending the ship, not refueling) were wide open. It wasn't so much of a mistake as an extremely lucky coincidence that the American attack happened while the Japanese carriers were in such a vulnerable state. I don't believe that its entirely inconceivable that an ISD could be severely hurt by an explosion in its hangar area, which would leave it open to further attacks.

[Sea Skimmer]

Agreed, the Akagi wasn't sunk by the explosions, but she was crippled enough that she wasn't considered worth salvaging, and for a fleet that had just lost half their carrier strength that is saying something.

She couldn’t be salvaged because of the tactical situation. Nagumo needed his destroyers for a surface action, and he would have had to use a cruiser escorted by several other units to tow the ship. Its not that it was impossible or undesirable, it just was not a viable option due to the continued US air and submarine threat. IIRC they did try towing Kaga for a while by the anchor chain, but its very hard to make more then 1 knot doing that. Later in the war the US proved that it was possible to tow and defend enormously damaged ships out of trouble. USS Houston and USS Canberra being prime examples.

And also, the Akagi was hit during flight operations, namely, there was ordnance lying around everywhere, fuel lines trailing everywhere, etc. To facilitate those operations many bulkheads that were normally closed during combat (because all the aircraft are supposed to be away defending the ship, not refueling) were wide open. It wasn't so much of a mistake as an extremely lucky coincidence that the American attack happened while the Japanese carriers were in such a vulnerable state. I don't believe that its entirely inconceivable that an ISD could be severely hurt by an explosion in its hangar area, which would leave it open to further attacks.

Doors being open had little real effect on Akagi, despite her total lack of flash protection (they had only single hatches on the munitions lifts, instead of an interlocking system)and additional warheads being stacked on the hanger decks, her magazines did not burn or explode. No one had effective hanger deck fire doors at the time.

Nor did all those exploding bombs manage to breach the armor deck, which was a worthwhile thickness unlike an Essex deck. It’s well within reason for an ISD to have its hanger deck gutted from explosions like that, but they just should not be catastrophically propagating like they are repeatedly in books. They must not only have zero flash protection, they must have munitions handling that is unusually bad to allow blasts to spread to such a reliably fatal degree. If you literally leave a chain of warheads from the squadron hangers to the main magazines then you’ll have trouble.

[adam_grif]

Could it just be that since fighters and the like are carrying KT/MT level weaponry and fuel stores, there's no practical way for them to armor everything to that degree?

[Sea Skimmer]

The reason I don’t assume that is simply that armor is way too prolific in Star Wars for it to make sense that it can’t even repel fighter scale weaponry. I mean why would the Death Star even be specified as being really heavily armored if the armor plain sucks? Why would the ISD have so much thick armor and massive turrets if this wouldn’t stop even the lightest weapons? Some of it might be for structure, but the theme of armoring comes up pretty damn often. All that armor is mass, which means a fair bit less less speed, its not like its free to haul it around.

[takemeout_totheblack]

There was a thread on durasteel somewhere else on this site and there was a '300k x steel' number getting thrown around. I don't quite remember who came up with the number, but I think it was derived from Executor turning stresses and the yield strength needed to prevent the engines from snapping the ship in half.

I'm not sure how well things like yield strength relate to a material's protective ability, but considering Acclamator durasteel armor plate has been known to shrug off fusion-bomb proximity blasts I'd have to ballpark it at 100 000x RHAs superior in terms of protective capabilities at least.

So I'd imagine fighter craft wouldn't be able to do more than pockmark solid armor with their laser cannons and other such weaponry, but I always imagined they were used to assault less hardy things such as an ISDs weaponry placements and maybe its sensor equipment to soften it up for their capships. I figured starfighters in SW were less anti-capship weapons and more tactical nuisances.

[recon20011]

Yes, fighters would probably not be able to seriously damage solid armor by shooting at it. But if an entire fighter cooks off inside a hangar bay... That isn't just the fighter's weapons going "pew pew" (or other suitable sound effect) at the armor, that is a big bomb going off. How much fuel does a fighter carry anyways? Your standard TIE that is carried onboard most Imperial vessels. I think that is the TIE/ln but I could very well be wrong.
And also, yes, fighters could try to knock out smaller targets, like anti-fighter weapons, basically anything that doesn't appear to have heavy armor. Plus, fighters are supposed to escort bombers, who are the ones who will do any real damage.