At outbreak of the war, you might try going East toward Poland and take out some Poles. Then try West of Bergen, thereīs usually some British ships heading for Bergen to sink there. Then go North East of Scapa Flow, always something to sink there
Go slow, 7 knots. Going faster will only burn fuel to no avail. To reach Scapa in an type IIa from Kiel and have enough fuel to get back to Kiel you have to conserve fuel, use the Kiel kanal. Donīt go chasing after ships that go at some 8 knots, the top speed of your boat is only 2 knots higher and you will burn a lot of diesel trying to catch up.
Oh, and welcome to the club