How long do DDs search for you once they manage to latch onto you?
I often experience hours and hours of evasion after an attack, and the escorts tend to search for me even after the entire convoy they're "protecting" has vanished from sight long ago.
It just strikes me as unrealistic that every escort would abandon their convoy in the hopes of finding little old me, and then dedicating tens of hours to this process. Yes, it makes it really difficult to stay alive because the escorts basically force you to surface eventually due to CO2, but it doesn't really make for fun gameplay when the game boils down to evading ten escorts for dozens of hours because they're able to locate me with pinpoint accuracy even when I'm at 150 meters, silent running and standing perfectly still...