Yes, the Kpt´s advice is good
Try to use the stand off range of your weapons, fire from 2000m or more, depending on the torpedoes you´ve got. Scope down and clear datum as soon as the torps has left the tubes. When the first torp hits, speed up to get deeper faster and then slow down to 1 knot and keep your stern pointing to your firing position. If you still get detected, follow the Kpt´s advice.