Attacking the British Naval base Scapa Flow is a rewarding way to start or end a patrol. It is one of the larger naval bases that the British own and is well defended. You will have to avoid the sub-nets, destroyers and coastal batteries. This can be achieved fairly easy.
This is the easiest way in/out of the harbor. You will avoid most of the nets.
It is best to stick to the coast line, and at dark/storm. (coast is just over there)
You will see a lighthouse in the distance, dont worry its 18km away...
...See
As the passage narrows you will see barriers (Sunken Ships) Pass by them
and then submerge (unless you want to become target practice)
Now go nuts, get it done fast then get the hell out.
After it's all over it should look like this
Or hopefully better
As you make it back through the Ship Barriers it's best to man the 88mm
that is unless you still have torpedoes