I've been playing campaign as Britian and Trinidad was pirate infested. I couldn't let them keep it so I attacked and conquered. They had a pirate ship in the dockyard at the time when caputring the town. Unfortunatly after taking the town the pirate ship was ejected to the side of the island. The patch of sea to the west of the island is not actually "connected" to the rest of the sea. This means that pirate ship is "stuck" there forever. I have tried to attack it but I can't get to him.
So just a warning to all other players untill this is fixed. Do not take over Trinidad & Tobago when there is a ship inside the port. Make sure the port is empty.
I hope to god my save games still work if CA change the map so slightly to allow movement in that patch of sea.
Edit: Hes gone now because I've killed the pirate nation... didn't even know they was a nation, lol.
That happened to me the first time I did it, but I was also able to maneuver around on the other side of the island to where I was eventually able to kill it. It took a while, but it did work after two or three turns.