Hi ridgewayranger ( sorry a bit late with the hi)
In SH3/GWX the bigger ship models usually have engines side by side or 4 square, and occupy the centre section of the boat. The zone parameters for the engines dictate that they provide a significant amount of positive/negative bouyancy, and essentally hold up the centre section of the boat. Probably somewhat similar to SH4 ship models and zones at a guess.
I thought of "staggering" their positions, but info on their actual configuration has been difficult to find for some boats.
"staggering" can also cause balance issues for the boats in terms of bouyancy and listng, which are not necessarily insurmountable, granted.
Sometimes the models are not historically accurate either though.
The German K-class light cruiser had 2 steam turbines and 2 back up diesels behind them, with 2 props. The SH3 model had 3 props and shafts. ( i did a mod for the German cruisers).
The Illustrious had 3 engines and props, as does the model, but the SH3 Essex class model is essentially a copy of the Illustrious model complete with 3 props.
The real Essex class had 4 engines and props.
I'm stuck with the existing models because i can't re-model the boats prop shafts to make them historically accurate. ( No modelling knowledge).
To Webster:
it doesn't seem to matter in SH3 whether you fire the torpedoes simultaneously or at intervals, the boats don't appear to be able to repair damge when hit.
Sometimes in SH3 the destroyers will stop for a while, which is good because it allows you to creep away on silent and change course, making it more difficult for them to pinpoint you when they get going again. But thanks

I try to keep my GWX3 game as simple as possible, to avoid mod conflicts.
To Munchausen:
If you hit the back of the boat it's a fair bet you missed the engines, and if the damage your fish did to the stern wasn't sufficient to sink it , it would indeed carry on and not stop.
The issue i posted about was concerning damage specifically to the engines, and why all the engines stopped when one engine was hit.
As it's turned out, even healthy engine zones are not watertight, so a hole in the bottom of the boat was flooding them, quickly.
I have however found a way to fix it by simply extending the flooding time of those zones considerably