If you are referring to the creaking and movement of bulkheads etc in the U-boat that are heard the deeper you go they ere the following files:
Creaks_Level1.wav
Creaks_Level2.wav
Creaks_Level3.wav
Creaks_Level4.wav
Way back I had a sound pack for GWX 1.03 & 2.01, about 32meg uploaded at Filefront together with 6 pages of mods I had done but they deleted them and I was too lazy to put them back up.
If these are what you are talking about then I could upload the above sounds and if they still don't have the impact you could go further to edit the sh3.sdl mixer file!
I am sure that others have modded this though!
If you are referring to ship bulkheads collapsing on their way down then yes their isn't much except for the files:
Scufundare vapor.wav
Scufundare vapor_hyd.wav