Assassin's Creed IV Black Flag social chest?

I have now got Assassin's Creed IV Black Flag again for the PS4. I would like to get the platinum trophy, unfortunately I need a social chest for that. I get the whale and the convoys en masse, but the chest doesn't stop there. I know it's an older game, but if someone has the current social chest spawn location, it would be nice to post it as an answer. Tips to find them quickly would also be helpful

Under the following link you will find a map with spawn points… https://forum.psnprofiles.com/topic/79734-social-chests-tips/

Found one.