Naval acadamy~torpedos~Manual targeting help.

[Freiwillige]

I am having problems with manual targeting and hitting anything. I follow the instructions posted before the mission to the letter. Here is a common scenerio describing my issue. Load mission, Head due east (This brings me close to the tanker that is on a course south) after about 30 seconds flank speed I order all stop. I pop my periscope up (Attack) and start my calculations
1.ship type (Small tanker) Check
2.Ship distance (Using the meter built in/Mast height) 800m's
3.Angle off bow (at first I was calculating off my bow but now I understand that its my angle off of his bow) 35 degrees and climbing.
4.speed (timed 20 seconds) 7 kts.

With periscope locked I fire so close I could hit it with a water balloon but the torpedo always aims behind the vessal and doesnt come close

Okay try again this time he's closer recheck calculations
1. check
2. 500 m's
3.90 degrees He's right in front of me!
4.speed 7 kts

Fire 2! Again way behind him what am I doing wrong?

I did a forum search but found no aswer