this is my theory about the map:
there are several "campaigns", each starting and ending on diferent dates. For example, on the screenshot we see the "mediterranean campaign" that starts on january 41 and ends on september 42.
this campaign comprises 10 patrols (1 iron cross per patrol can be seen on the screenshot), those 10 patrols are grouped on diferent "events" ("mission gibraltar", "conquest of egypt" and "malta surrender") with a diferent amount of patrols each (4, 3 and 3).
the light iron crosses are completed patrols and it seems that the player can choose what "event" he want's to play next, and engages on the first available and not completed patrol of said event.
that being said i think each patrol is scripted up to a certain point (orders and stuff), and the dinamic part of the campaign includes: ships moving from port to port between and during patrols, the already mentioned "ship roster", the date of the patrol starting (you can choose the patrol you want to do, remember?) and maybe some other stuff.
if that's the case, the replayabilty might be really low, i was hoping for a SH3-4ish campaign with extra elements
, and that being said, i hope i'm wrong and the crosses are just "keep up the good work" thingys...