yeppers, noticed that too
oddly enough it's not so noticable when in the north sea off Aberdeen. but from 1940 onwards I always stay submerged by day, it's better in shipping heavy areas anyway, hunt by hydrophone.
also, until end of 1940 I find it worthwhile to slip between Orkneys and Shetlands, submerged by day, surfaced and 12 knots by night. it's a lot shorter and you're almost guaranteed a shot at one merchant just to get you off the mark.
It's not as bad as near Gibraltar though, that's just not funny, trouble is some of those planes are spanish and I even crash-dived for a Condor there
