Thanks a lot for the feedback
I already discovered the conning tower flags before and already using them
About the 360º hydrophone, it is working, only thing is I have to dive to 20-30 meters for it to function properly and reduce the speed to ahead slow. I'm getting contacts now and just sunk an entire convoy of 16 ships yesterday with 2 destroyers

(with a load or two in the middle because of CTD's.)
BTW, have another question, I said before I was in Happy Times campaign but I was wrong, I am in the first one before Happy Times. I have Open Horizons II installed and already finished British Eastern Supplies, Northwestern Approaches and Breaking the Fortress. I am at 15th February and still no new missions (the last one I finished was Northwestern Approaches around 15th January). When does Operation Wesenrubung and the another mission become avaiable?
Also, when I finish this campaign, does the game continue normally and the game continues automatically into Happy Times, or do I have to start a new campaign? Will my crew retain all its abilities and skill points, or will I have to restart from zero?