so I tried out a 1940 scenario in deep water vs 3 "competent" escorts, 2 corvettes and 1 sloop.
At first I thought I was on to something since the escorts had trouble locating me and dropped DCs far from me:
but they eventually zeroed in and sunk me with the third DC attack which was spot on and at the exact depth:
The DC mod helps, but I think the IRAI AI is just too good.
