Happy New Year!
I do not recognize many of mods listed in your post no #4.
However I would like to suggest you something,
in case that is really sound-related problem:
Take the “original”
sh3.sdl file from
LifeBoats&Debris_v4 and insert it again in your game on the top of all other files. Do it with JSGME or directly replace it inside folder “Sound”.
Try again to sink the tramp steamer or the coastal tanker inside Academy or in single mission.
If the problem persists, compare the
NKSQ_.dsd file from NKSQ_ folder inside Sea folder with the original NKSQ_.dsd file from GWX.
If you have not/you don’t like (?)
S3D, you can compare with
WinMerge (freeware), it will tell you if files are identical or not.
My idea: if it is a sound problem, and is not a sound card problem, perhaps is a .dsd or/and sh3.sdl conflict.
If nothing works, disable the
GWX - Enhanced Damage Effects and every mod on the top of that, and try again. But in this case, I thing, should be a graphic card problem
(weakness).
If GWX - Enhanced Damage Effects
works fine, without all other mods on the top of it, consider that you are lucky…
If not, I hope that somebody more skilful than me, will get the answer...
Good luck