In late -41 it was hard to find convoys because the enemy would know your position if you used the radio. I think it's because they cracked the Enigma for a while until the Germans could change the codes. If this is simulated in GWX then you got the reason.
In -42 the place is US east coast in a XI, and in -43 you should change to a VIIC/41 and hunt single targets. Do not attack convoys, unless you really wanna die for Der Führer
