[magic452]

What i would do if I were you is to approach the TF or convoy at an angle of about 65 to 70°. This puts you clear of the flanking DD but still gives you a good shooting set up. Try shooting at longer ranges, around 3000 yards.

Try to get as good conditions as possible. Bad weather is best for you.
In good weather try to trail them till night to give you the best chance to succeed.

Plot the course of the main ships only, forget about the escorts till you are almost ready to attack.

With auto targeting the best you can do is shoot one or two ships, the longest range ship with the torpedo set to slow and fast for a closer ship.
dive deep and silent 1 to 3 knots max.
Once the ships start zig zaging auto is all but useless.

Manual targeting is not all that difficult to learn. Just takes practice and patients.

Use a single war patrol and go to the Luzon Strait, find a good single ship and save the game as soon as you do. This will give you a good set up for trying manual targeting, if you don't get it right just reload and try again.
Once you get plotting it's course and speed the rest is pretty easy.

If you have manual targeting turned on than there are several other attack methods you can use, O'Kane and vector analysis are very good long range shooting methods.

Magic