Welcome aboard Hanzberger
Play the mod using SH3 Commander (IMHO a must have) and you can control who receives what and when.
All renown for going to and staying 24 hrs has been disabled. The renown for returning to base has never worked, not even in the stock game.
When you chose 1st Flotilla did you choose a Type IIA?....if so, they were never fitted with an 88mm deck gun. Far better you choose the VIIB.
Ship sinking times vary, depending on where the damage you have inflicted is situated. Ships that sink as a result of flooding take time, just as they did in RL. It is difficult to put timescales on what is such a large variable.