Boy, that's a toughy...
Being that it's 1941 I would be inclined to attack.
My strategy would be to stalk the convoy at 3 km
or more, set up a shot toward the front of the convoy,
take it, and then launch a salvo toward the rear. I would
then slink away post haste. The key is the range.
I would also use every bit of the 88 meters available
