Total Germany - 1st Mission problem

[harag]

Hi all

I've completed the tutorial and now captain of my own ship, I received my orders to partol area East coast of Britain near the Grimsby port. I sailed over there and partolled around but couldn't find any ships, then thought I would check out the port, sailed over to the port and sunk 5 ships and gained a 52k tonnage - more than enough for the mission, but my mission hasn't completed? Heck I'm out of torps and gun ammo, so sailed back east to resupply.

I don't understand why the mission has completed? I've got the tonnage - was it because the grimsby port isn't in the same square as the mission icon?

Do I have sail in and around the icon and sink ships there - what distance can I be from the icon for it to count?

Thanks for any help/advice.