One more piece to the puzzle

I'm still confused over that 95 m turning radius...do you suppose it could be a typo and someone left the comma out?

Type VIIA --- VIIF, length of boat: 55.3 m --- 77.6 m
Type IXA --- IXD/42, length of boat: 76.5 m --- 87.6 m

In all cases, the turning radius is larger than the length of any boat that saw service.

To make a 90 degree shot, lets say to the port side of the boat for example, the torpedo would first travel 9.5 m straight ahead, then begin to slowly arc to the left making it's 95 m radius, bringing it's total length away from the bow caps 104.5 m !

If the target ship was Range: 1000 m, AOB: 90 degrees off my port beam, doing Speed: 10 knots or making ~309 m per min. The torpedo is making 936 m per min., it appears my shot would miss in front of the target; however, applying the bow distance formulae, i.e.,(Law of Cosines)

BD = sqrt ( 1000^2 + 104.5^2 - ( 2*1000*104.5*cos 90)); then, (Law of Sines)

Gyro angle = arcsin ( 1000 sin Br / BD) = 84 degree gyro angle

Now the shot would barely miss abaft of the target...

How much (+ or -) parallax and/or convergence to make the collision take place?

The Sailor's Eye: I personally believe that each skipper, during his training in an actual boat making his manditory surface and submerged practice shots, learned how much to add or subtract through on-the-job-training (OJT), that is to put "Kentucky windage" on the shot to make a hit. Although their success rate seems to indicate a much more scientific approach. I guess their expertise and knowledge has been lost.

Cheers,
Don