[GT182]

Here's a way to evade:

When you attack a merchant dive and go deep as fast as possible turning away from your attack course, and go Silent... the DDs seem to know where you are when you fire. (That's how they are in my career so far... Nov 1940) Once you're below 130 meters, slow to 1kt. If the DD still has you and is circling, head off in another direction to get out of his circling path. If you can do that and he passes you by stop engines and sit still. Have your stern facing him during this if you can. Once he's turned tail to you start moving at 1kt again. When he's getting ready to face you again, stop and sit. This might take an hour or to 2 get far enouch away from him but eventually you be past his sonar range. Once out of his range, if he keeps on his present track you'll be able to increase speed to 2 kts and stretch your margine of safety. If you get "he's pinging us", just sit tight as it doesn't necessarily mean he knows where you are, he's only is trying to pick you out. Plus the "thermal layers" are helping mask you.

I just went thru this with a Black Swan DD in BE3. It took me 2 1/2 hours in real time, but I escaped without a scratch.