Hi,
I understand this, but I have never seen any problem with this

Maybe because I limit the convoy speed and the max. column size and thus, the outer ships can always easily catch up
I agree that it's not like a historical zigzag pattern, however, it makes the game significantly harder at least for me. Attacking/Shadowing a late-war convoy in the Atlantic without map updates and many escorts with radar is now really tough.
Cheers, LGN1