Man was I lucky. Oh yeah and now i see i forgot to say that my hydrophone was destroyed.
I tried with the torpedos but no luck, just couldn't determine their location. I went back to 70 meters and 2 knots speed.
But finally, at 3 am the 3 destroyers started drifting away. There was still some pinging at 4 am and at 4.30 it was around half hour without pinging, so i took my chances, surfaced the boat and I was simply delighted.

They were gone, full speed ahead back home.
My batteries were down to around 5% and CO2 levels almost in red. I probably used all my luck this time.
Mission ended with two kills, one Granville type freigther and one J&K class destroyer. 2 dead seaman, 1 dead petty officer and hull integrity of only 37,17%. I also received iron cross first class after this patrol.
And now since it's friday its time for some r&r in the local pub.
Oh and thank you for your help