Well, in my testing I think I went too far the other way, with shooting by guessing the correct angles and doing the hip shots. I don't see any evidence that real captains actually did that. You have to remember that when they got back to port their cruise reports were criticized line by line.
Departing from established procedure took with it a real portion of career risk. If you were to do what I did and wipe out a convoy for over 100k tons, you would have produced more tonnage than any other boat did during the entire war. I think it's safe to imagine that your job is safe.
However, trying the same idea and coming home with a goose egg or a couple of small freighters would most likely be the beginning of a brand new life, captaining the base garbage scow. There was strong pressure to go with what had worked before and not to try new ideas without running them up the flagpole beforehand to see if the idea got shot at.
Actual approved procedure consisted of
- One target at a time. No multi-target salvos
- Get in darn close, well under 1000 yards
- No torpedo is fired without a valid solution, checking target position against TDC position
- Fire a spread of three or sometimes more at every target
- After that target, look to engage others on the same basis or evade as the situation requires
I read of one surface attack by Wahoo where they fired on two targets at once. That was a notable exception to the norm. They were much more conservative than we are.