Welcome aboard!!
If your goal is to learn the full-monty manual targeting mode, this won't be of use but if your main interest is in sinking ships using manual vs automatic targeting, I join a number of Kaleuns using the "O'Kane method" that greatly simplifies torpedo angle calculations. It has become my favorite manual targeting method, and I reckon if it was good enough for Dick O'Kane, it's certainly acceptable to me.
Search this forum and
YouTube for more information.
Good hunting!!