I hunt down radio contacts, provided they're not too far off course. I tend to plow on towards my patrol grid first though, and get that pesky 24 hours out of the way. I dive until batteries hit 75%, then I surface and recharge, rinse and repeat.
When I can't find anything or i'm out of torpedo's on my way back to base I sometimes send in spam reports to BdU to lure in the british air patrols. This morning it backfired on me though, my IID got hit and I was forced to crash dive
