TMO - What's the % of dud/defective torps 1942?

[groomsie]

So finished my patrol last night, chasing down that merchant and getting into attack position ahead of him at sunset, range ~ 500 yards. Fired all 4 stern tubes (figuring if I'm lucky 1 goes off), 2 contact, 2 magnetic. All 4 hit and went off, target destroyed. Figures, wasted 2 torps I figure.
Sonar then detects another merchant approaching from the east, a little observation and I realize he's also coming right at me, so I set up for a bow shot, range ~ 600 yards. I fire the remaining 3 bow torpedoes at the medium old composite and--you guessed it--all 3 hit and exploded. Again, at least 1 torp wasted (with more reliable torps at that range I'd fire just 1 for a small or medium and then depending on how much of a hurry I'm in and/or how the target is faring, will fire another torp, finish with deck gun, or just wait...).
So, overall for the patrol out of 22 torpedoes, had 3 misses, 19 on target but 11 defective (either outright duds or ran under target--no prematures though), 8 worked (my first and last 7 for the patrol): 86% on target, 42% of those on target functioned as intended (or at least inflicted damage).