For the moment I'm finishing off the side quests in the current version of the "Nelson" storyline. And the in-game character Pieter Boelen is confused. 
I'm to help the pirate settlement of Turks Island (which is owned by Britain) against a Spanish attack from Saint Domingue (which is owned by France). I've got as far as talking to the Spanish officer in the tavern of the not-Spanish Saint Domingue, followed by the beach encounter. Next play session will probably see the Spanish attack on Turks Island, followed by Pieter asking me to take him to La Tortue (which is owned by France). So basically I go to a French port to help a Dutch pirate who wants to defend what is now a British colony, then take him to another French colony to get more help.
The Spanish attack on British Grand Turk would make even less sense if variable relations hadn't randomly put Spain at war with Britain. By default in this timeline Spain and Britain are at peace, which would make the Spanish attack on Grand Turk the 18th century equivalent of Pearl Harbor...

I'm to help the pirate settlement of Turks Island (which is owned by Britain) against a Spanish attack from Saint Domingue (which is owned by France). I've got as far as talking to the Spanish officer in the tavern of the not-Spanish Saint Domingue, followed by the beach encounter. Next play session will probably see the Spanish attack on Turks Island, followed by Pieter asking me to take him to La Tortue (which is owned by France). So basically I go to a French port to help a Dutch pirate who wants to defend what is now a British colony, then take him to another French colony to get more help.
The Spanish attack on British Grand Turk would make even less sense if variable relations hadn't randomly put Spain at war with Britain. By default in this timeline Spain and Britain are at peace, which would make the Spanish attack on Grand Turk the 18th century equivalent of Pearl Harbor...