Manual Targeting - Periscope Bearing

[CajunRon]

I am new to submarine simulation and so I'm on a steep learning curve. I've set up a simple "practice" mission to check out different things. I put a simple "dead in the water" freighter pointed on a heading of 90 deg with my sub due south at periscope depth 1000 yds away with a heading of 0 and bearing of 0. I set the AOB at 90 degrees (perpendicular). Once I fire my first torpedo the freighter starts up but continues his 90 deg heading (I've dummied him way down). What I just noticed is that if I follow him with my periscope until he is at a bearing of 20 deg, leave everything else alone (no PK, 90 deg AOB, 0 speed, but set a new distance) and fire a torpedo, the torpedo tracks due north and does not turn at all. I thought that even in manual targeting mode the torpedo would track to the bearing that the periscope is looking. Is this not the case? Is there no true "kentucky windage" firing mode that just shoots in the direction you're looking?

Thanks for any help.