Good luck! Hope you get some tonnage!
One thing I neglected to mention in this is the stock bug with SH3 in which large ships with deep drafts in shallow waters sometimes settle on the bottom without "sinking" and the poor Kaluen gets no renown.
There is no way to predict when this will happen but you can reduce your chances of it impacting you by aiming for weak points such as ammo magazines or fuel bunkers on your targets.
Gute Jagd!