I hate it even more when it happens again, even after reducing the torpedo depth settings. Heavy seas and unreliable torpedoes are not a war-winning combination.
Looks like the magnetic pistol failed, but the sea state may have been the problem - one school of thought in SH3 is don't waste eels in heavy seas, shadow the target till the conditions improve.
Two short clips showing U-33 breaking contact with the convoy in the storm.