Now this naval mission may well be the trickiest in the game. You will well and truly need to upgrade your ship to level 5-7 armour (the more the better) and upgrade all of your weapons to as high as you can go. The goal of this mission is to destroy two Hunter ships.
To get the Hunter ships to appear, we need to find and attack ships in the nearby area until our notoriety/wanted level rises. This can be tracked by the red crossed sword icon above your health bar in the top left corner of the screen. By attacking ships, this will slowly fill up and when it is full a Hunter ship will appear.
Trying to do this in the Charlotte fort’s surrounding area is a death wish and although it’s not impossible, the fact that you’ll be swarmed by groups of frigates and a man o’ war or two the as soon as you try to initiate combat here makes it more frustrating than challenging as each time you die, the wanted level will reset to what it was when you began the contract and you’ll have to build it up again.
To make things a little easier, set a custom waypoint over near one of the medium level forts nearby (Cabo de Cruz or Castillo de Jagua should do the trick) and eliminate the ships around there. These ships are set at a lower difficulty level, so you should have less trouble building up that notoriety without it being reset every time you desynchronise.
So once you have earned your wanted rating, engage, attack and sink two Hunter ships and the mission will be completed.