The crush depth on a VIIB is around 150M I think...In a type IXB I was depth charged pretty acurrately near the stern and began to sink backwards due to flooding. The crush depth on an IXB I think is around 170m, and I went straight to 197m and the boat was making some nauseating sounds...Absolutely horrifying, but my engineer began giving me vocal warnings, and I never did start taking damage to any other compartments and what not.
Sadly, I don't know if you start taking damage along the ship's compartments or if you're just squashed instantly once you spend too much time at crush depth.
