note: all this data has been gathered between september of 39 and april of 41
also I'm assuming GWX here,
BF17 to CG48 A good line to follow for outbound convoys, mostly cargos some tankers, sometimes a bigger warship.
the eastern half of AM36
CG94 except for grids 1 2 and 3 (but you knew that
)
also goes for CG86 although less so as well as CG95 grids 4 and 7
Any grid starting with BE3x mostly inbound convoys
AM17 18 19 and 01
AM53
and between 9-3-1940 until half of april 1940 definitely check out AF8325, but be there early or the nutcases in the Stukas will have sunk all the lovely troopships.
Now, obviously, looking at the map you will notice some of these areas are in shallow waters and definitely within aircraft range. This might result in big red exclamations along the lines of
OMGWTFBBQ STAY OUT OF DER KANAL and so forth
and I couldn't agree more, but sometimes that's the chance you take for nice tonnage
other no go areas IMO anything starting with AN7x or AN8x, unless of course one is fond of mines and MTBs and planes in 20meters of water or so
I've also sort of come up with a no go chart as follows
with a type II sub in 1939 don't go near anything with less than 25 meters of water
add 50 meters to that figure for:
a: type of submarine above II (so add 50 for a VII 100 for a IX)
B: every year after 1939
Ignore tables at own risk or for more than 20k tonnes of warship