Issue with sub not turning when moving under water?

[hunter301]

Is there a glitch in the stock "Uboat/gold edition" of the game?
I was running the training convoy mission practicing my shooting.
Anyway I was duking it out with the destroyer/escorts that come at you right off the bat, sunk two right away then two more came in. So I went deep 300 feet and slowed to 1/3 while I reloaded. Escorts lost me because using my F11/God'seye key I could see them both together depth charging way in the back ground. So fully loaded I decided to turn back to them come up to periscope depth and hopefully catch them both running crossbeam to me with a full load. Problem is my damn sub would not turn so I could head back to them. I swear I watched that orange arrow for two minutes looking back to the escorts and it never turned. I tried speeding up to see if I was going to slow to notice but nothing worked.
Has anybody had this happen? It's very frustrating because everything I have read says that a sub underwater can turn tighter than an escort on the surface.