My last patrol (mid-1940) was fraught with terrible weather, high seas, thunder and lightning. I would guess that the vast majority of my torps blew up prematurely. I guessed it was because of the high seas and them broaching and somehow getting triggered by the waves. A totally lousy patrol. I couldn't
wait to get back to port. Hell, the weather was lousy all the way back too...
As an aside, even trying to target the enemy was a pain. I think I sunk one ship on the whole 'cruise', and I accredit that to pure luck.
Hard to amass renown when you come back empty handed.