Thick fog - fairly rough seas. Picked up an enemy contact and just happened to be in the perfect position to fire. I don't use "external view" and through the fog fired 2 torpedoes at the obvioulsy large, but very indistinct shape in the periscope - range less than 500 metres and I still couldn't see a damn' thing. Both were hits. It went down fast.
When I got back to Wilhelmshaven and docked - I was pronounced dead!
I only hope they allowed me a last cigarette before I faced the firing-squad; and in future careers I've ensured that I don't fire unless I have positive i.d. of the type and nationality of the target.