None of my files are really tweaked and tested. I lost all my work recently. Really all I've done so far is increased the
flotability= to a greater number making the flooding more deadly and decreased the
critic flotation=.
If you really want to make it fun make some explosives on the deck gun, diesel engines and fuel by using the
multiplier=. This way you can simulate critical hits.
You can also put
flotation= on the non-room zones. What happens then when a non-room with flotation gets destroyed you get "ghost flooding". This can cause a permanent list that won't be corrected until you return to port. I haven't tested the effects of this underwater. I'm more of a surface ship guy. I can imagine it would make maintaining depth very difficult.
For the guys who are new to this I highly recommend backing up the files you work on and testing your changes in a small mission versus a destroyer. Let him kill you. It's all trial and error with a bit of logic. I've found it to be more fun than the game at times.