One thing to remember about SH4, is you don't have Admiral Lockwood or Fife to chew on your backside when you come back, so if you are taken to a location from a "Proceed immediately to Convoy College and standby for further orders!" (or some-such) and once you arrive there, you get "You are to conduct anti-shipping operations. Spare no mercy!" (or some-such), there is nothing binding you to that area. Allow for fuel consumption, and go where you can find ships. In the overhead radio rack in the Control Room (if I'm remembering my TMO correctly) should be a link for a "Convoy Routes" map that you can look at to get ideas from. Go and be careful! Sink 'em all!