>>11077371You can get boat parts off Bricklink for pretty cheap. I mean the hull bow/stern bricks, both the six-wide and the wider ones. The mast pieces you can get for a dollar each too. Basic bricks, plates, and other common parts can fill in the rest of the hull. I bought the new Eldorado sails off Bricklink to make picrel, but to save money and have more custom shapes you can buy a square of plain calico fabric for a few bucks and cut out your own.
For minifigs, check out PaB. They have the soldier parts from the new Eldorado Fortress plus pirate hats, torsos, and weapons. If you want classic ones you could buy them on Bricklink or keep an eye on FB marketplace for good deals.