fwiw: Some years ago, I picked up a 4 vhs set from the history channel re The Silent Service
The Torpedoes of WWII
The Captains of WWII
The Boats of WWII
& The Attack plans of WWII
narrated by Roger Mudd...great stuff. donno if it's still available; but, the torpedo problems of deep runners, magnetic influence detonators, and impact detonators ran submariners ragged for two years. It was truely a harrowing story.
I've run these things to where almost all the emulsion is rubbed off the tapes
we're all getting old.