Just sunk one this afternoon while I was playing. Had a 89 degree AOB had my tube door open and hit the fire button at 001, or 359 if he is going the other way. Torpedo was set on impact at 4.5 meters. No preset section of ship was selected just on auto. It went up in a fireball and sank within 1 min. Calm seas
Try it see if it will work for you as well.
