You must plan ahead all attacks you make much more carefully because of both the reduced speed of your torpedos and - more dangerous: the reduced speed of the Sturgeon class boat compared to more modern subs. It doesn't seem much of a difference at first, but running only at 25 knots max speed will make it much harder to evade torpedos, so better be far away once your torpedos hit.
How? Use your wire and first send your torps where any snap shot from the enemy cannot harm you. If you have to evade torpedos you must do all maneuvres much earlier like changing depth, using decoys or knuckles etc.
If you find it too hard to start, then maybe start a campaign with a faster sub that can go at 30+ max speed and see the difference
