Hmmm ya know this brings a thought about something thats been on my mind lately. There is that option when in base before shipping out where one talks to the commander, and in that dialog there is the option of starting patrol without selecting a mission.
So it seems to me now that one can if one so wishes, simply do just that. Go out on patrol to anywhere you wish and sink whatever you wish. The ships and tonnage will count, and you can rack up quite a score. The only thing is none of it will count towards the missions and campaign.
But what im thinking is, that what you can do is mix it up and sometimes just go on patrol without a mission, and sometimes select a mission so that you can have campaign progress.
So just do every other patrol as an official mission for instance, and the others in between as non mission patrols. Thereby satsflying one's need to roam where you see fit, sinking what you see fit.
Hmmm, freedom of choice. What a grand idea.
