I definitely have to agree with Furia, I have played the game for about 28+ hours now. Yes, the U-boats turn tighter than the DD, that's not only historical, but without it, there wouldn't be much of a game.
I think after you have played the game more, you will see what I mean. We have radar to start the hunt, then we can get within sonar range before they dive. So, we usually get sonar contact quickly. If we don't get sonar contact then we can spot their periscope feather half the time. It's not too difficult to hammer the sub non-stop. So, we don't want the sub to be any less maneuverable than historical subs were.
A lot of time I would have a string of contacts, make an approach and the sub outguesses me, turns and sprints enough to avoid my DCs. That's ok, because I know he cannot keep that up forever. As long as the game makes the speed/duration of batteries historically realistic as well... ha, I am making his life hell just keeping him under.
A U-boat commander would use every trick he could to stay alive. He knows when a DD is after him. He knows what the DD commander is trying to do. So a U-boat commander will vary speeds, depths. He may creep at a battery-saving 2 knots until the DD is closing, then order hard rudder, full aster to one screw and full ahead to the other, pivot (or close to a pivot), then all all ahead full and hope the DD player did not change his attack approach at the last minute.
I have had U-boats turn away sharply at the last minute. I've also had then turn right into my path... then my DC attack usually strikes hard.
