The strange thing with my ship frozen in place that I reported: I figured it was because I had gone "too far" outside the radius of the first mission in the campaign, the Baltic Operations mission in Danzig Bay. I had made it to Kiel by about 2 Sept (after having "completed" the objectives in the Danzig Bay mission), and had refitted but not "End Patrol." I had then proceeded through Kiel Canal (by pilot) and toward Grimsby. It was on that route that I dove (because my watchmen spotted something) and after trying running deep for a while (and suffering the zero speed bug) I also tried Periscope depth and surfaced, and had the same bug. Reloading the last save didn't fix it.
So, in this case, I had made it to within a few hundred kilometer of English coast by about 4 Sept, and BEFORE the mission check mark for the "Eastern Coast of Britain" missions showed up on the map.
I backed up and tried a different route. I Ended Patrol, and I was shocked to learn that my boat spent a MONTH! in Kiel!? Wat!?
So I tried yet a different tact: I waited till afternoon of 4 Sept bobbing in Kiel harbor until I saw that the "Eastern Coast . . ." mission widget has been rendered. I wasnt' able to ask for mission (apparently despite the marvels of radio technology and the Kriegsmarines penchant for chatting like school girls on the damned things one has to actually be in a PORT to "ask for a mission!?!"
). Anyway, in frustration at the obscure hoops the game seems to present to the player, I decided to just chance it, and head out on my own without Ending Patrol.
So I head north past the Danish archipelago and through Skaggerak. Now it is early morning 8 Sept 1939 and I'm outside Aberdeen harbor prowling in for a kill . . . IF there are any British or Oz ships in the port.
I'm guessing that: these arbitrary limits on finishing/taking on missions are a result of lazy programming by Ubisoft and not something easily worked around *sigh*