How to intercept?

[Pistoliero]

Originally Posted by desirableroasted

The point is to conserve fuel so as to have as long a patrol as possible. More time on the lake, more targets, more kills. Zipping around every time BDU burps is the fastest way home with nothing in the bag.

Not sure about conserving fuel, I use flank speed for intercept and rarely reach even 75% fuel remaining by the time, when all torpedoes are spent and I have to return to base.
Sure some common sense helps (don't interecept targets which are fast and moving away, don't interecept single ships 400km away etc), but it seems like only type II boats suffer from any sort of fuel shortage.