Was on the surface heading back to port came across what i thought was a lone destroyer. Pitch black, rough seas, fog and rain. Couldn't see 10 feet in front of me, nor did the destroyer pick me up on radar. I had two torps left and thought iim nearly home mos well get rid of these fish, so I fired both torpedos straight ahead and just hoped for a kill - i have no idea how far target was. I fired torps did a 180 turn and hit flank speed to get away in a hurry. Few minutes later i heard a explosion - then a "shes going down" went to my tonnage screen and got the shock of my life. I sunk a light carrier. BLIND.
That was one fluke.