When you see how the britains are working, you'll be wondering, why the germans lost the war.:p
Got a convoy contact and tried to attack. Send a contact Message and got back "Destroy the escorts". mh...ok. As they heard me (they MUST have heart me, 'cause my well traineed sonarman said, that the escort captain farted) 1 of them stopped immediately while 2 others speeded up and turn into my direction. Well, shot the standing one and got deep. After the charges emergency blow to periscope depth, came a bit surfaced, but got down again very quick. That was too much for the guys: all stopped while the freighters were moving away.
On the other hand: with light fog you get sight contacts in a range of some kilometers where I can't see the enemy. But they see me...