umm, I've done several night-time surface attacks on convoys without such issues, it was probably bad luck running into an experienced crew on that Flower, I don't think one example says it all, I haven't found GWX impossible at all, yes it's more difficult but in 1939 an 1940 I can mostly roam and hunt with impunity unless I get stoopid
or unlucky
But these things happen, variety is the spice of life, next time you'll get see them before they see you and then it's your party....