Danlisa!
I stayed at silent running, same depth, speed and course. I did nothing that would have changed my detectability (not a word...I now :-))
In the cases I can remember it has been solitary escorts, so no herd to protect.
It is SH3 1.4b+SH3 Commander 3.13+GWX 2.1 and the only mods I have are 16 km, Lifeboats 3B, Torepdo Damage 2, GWX Open hatch, 26th April fixes and Armed Trawler fix