I've repeatedly crosses the passage north of Scapa Flow, in both my IXb and my IIa, I did get some planes in early 1940, mostly Ansons, although with the IIa I got mugged by swordfishes, usually 2 or 3, I shot down 5 with no damage to the boat....poor stringbags
They're out there, just cruise along on the surface in good weather and attack the first merchant you encounter with your deckgun, they'll find you
