When i fired torpedos inside a convoy withouth check that another ship blocks the way to the torpedos at 100 meters (all duds)
crash dive from periscope depth in the english channel and not check the bottom depth, i was depth charged by a destroyer and one of the crew died (first patrol, no integrity of the hull enabled, a lot of pannic

)
stay firing with the deck gun at night at a coastal merchant in the english channel until i saw a search light, very close, and the shells falling , one hit near the gun but no casualties.
Put the incorrect AOB in manual TDC ,Port to starboard.
Travel to the nord to see icebergs Tc enabled, oh the phone, a call ... when i return to the computer ...the sub is in the ice cap