u/HeadbangingLegend

I forget the name of which treasure map it is but it's the one that gives you coordinates 113, 13 at the bottom left of the map. I just did the mission Black Bart's Gambit and while I was still in the area tried going for that treasure but there's an invisible wall that makes my desync when I try to sail to it. Do I have to come back after doing some more of the story or do I need to reload a save to get it during the Black Bart's Gambit mission?

Only thing I'm really confused about in the game is the "crew" resource and the point of rescuing floating people or gaining crew from boarding raids because it doesn't seem to matter at all. As far as I can tell I can't even see how many "crew" I have when I look through all of the pause menus to let me know how many I currently have. I never seem to see any issue about losing any of them during naval fights or boarding raids either I just need to worry about mine and the ship's HP. I keep picking up random people and getting +1 crew but where do they actually go??? I see upgrades for things on my ship like upgrading the number of crew I can have from 10 to 20 but what's the point in buying that upgrade?

Does the crew resource even exist or is it just a pretend thing that's nothing more than a "+1 gained" number on the screen when you get more?