I have to disagree with not being able to elude the DD. I have been toying with two of them protecting a convoy. Including an armed trawler. Three times I have purposly made noise to get their attention and I have eluded them all three times. Sure they hang close on the surface to me but speed off to the convoy after about an 1/2 hour. They throw DC without much accuracy at all. Realise this is 1939 I'm doing this. Furthermore I damaged a merchant that has finally lagged behind the convoy and alone. I surfaced for gun action and the DD about 5000m off cannot hit me worth a crap with their cannons. Actually, I'm starting to get darn cocky with the DD....
I evade using:
Depth: 150 or so meters
Speed: 2kts
Silent running.
Change course every 5 minutes or so.
Currently it is almost dark and I'm planning on a rear attack on the convoy, surfaced! Lets see if the DD find me
I like the GWX warships....make it more challenging!