Just finished up this mission. I had sunk the Ark Royal in earlier missions and it
did not count towards the Blockade goal. I was fearing that I was royally screwed on completing this one...
I finished the Northern goal by sitting right by the patrol line arrow off of Scotland and kept using Reveal Hidden enemies to find the armed victims.
Luckily I found another carrier (Hermes Fleet Carrier) and escort screen sailing between Plymouth and Cherbourgh. I managed to position myself where I'd be inside the screen if they passed by and went down to around 100m. Sure enough the plot was good and they came past, I popped up to periscope depth and fired a snap salvo at the carrier. Two hits out of four, but she was badly damaged and stopped in her tracks. The escorts took great offense to that and came after me with a vengeance. I snuck out of the depth charge barrage (which was a bit dicey there for a bit) taking a fair amount of damage but staying intact. I was able to get clear and fire off another two eels which blew her to kingdom come.
