Burning? Does your source specify how this burning might come about?

The whole subject makes me feel horribly claustrophobic, but I would have thought drowning or crushing would be prime candidates, followed by starvation in certain strange circumstances. But you specify "sinking", which simply adds to my confusion. I think you'd better explain how the burning would come about.

Pete

I assume that your friend had in mind that if the hull had been dramatically breached, the abrupt increase of air pressure would cause a rapid rise in temperature.

This certainly happens, but not necessarily as simply as one would expect in the cylinder of a diesel engine. A submarine at a depth of 200 metres certainly experiences pressures of some 20 bars, which is a fairly high diesel compression ratio, but if the compression is gradual there is likely to be water that absorbs a lot of the heat. If the compression is catastrophic I doubt that the crew will be conscious long enough to notice the heating.I do know that compression in airlocks causes heating, but that seems to be a minor consideration in practice. I assume that the reason is that the compession is not catastrophically sudden and there is a lot of moisture.

Not that I am offering to experiment and report on the matter in person of course.

This dead

by adiabatic compression would afford, that the sub is really

crashed flat in an instant.

This is very unlikely. When a sub goes below the depth

it is designed for, first some weak points will deform/disrupt.

Those weak points are valves, pipes. domes which penetrate

the hull. The sub is then flooded by the water entering through

this parts and the end for the sailors will be drowning.

Someone standing in the way where high pressure water

sprays in, can be  killed mechanically.

Georg

Georg,

What you say is much along the lines of what I was suggesting, and I am sure that it is the commonest effect, but remember that the ideal depth charge or torpedo strike will commonly cursh a pressure hull quite abruptly. So I could well imagine that the adiabatic collapse could happen at times as well.

Not that the difference would often be significant to the sailors of course, but it is hard to get direct testimony of course...

Not a pleasant subject!

perhaps if an air-pocket is created when part of the hull is breached  but the rest remains intact then the air in the air-pocket would prob be compressed very quickly and might cause a combustion...