it costs 20,000 doubloons
Well on each island, usually in a building there is someone you can hire. each of them have different uses and expenses. All them cost doubloons to hire.
you go around to each place and sell your cargo
The person you can hire on Bouffant bay is inside the warehouse. He will cost you about 15,000 doubloons.
You have to talk to the police
You should buy the NAVIGATOR (12,000 doubloons) in Parrot Port. She increases the speed of your vessel.
All you do there is to hire the Cargo Master, when you can afford him (salary 15,000 doubloons).
Nothing immediately. You need to get the largest ship, the Phoenix warbird, and hire the Shipwright and the Cannoneer. Once you have defeated Captain Crawfish, you can go back to the governor and get the directions to the treasure buried on the small island.
When you have the navigator on board (a skilled crewman) you can sail faster. Hire the navigator at Parrot Port.
The navigator is in Petey's Pirate Pub at Parrot Port. She can increase your sailing speed if you hire her.
Any order you want! But You Have To Buy Every Single One, To Beat Captain CRAWFISH!
Once you have the largest ship (the Phoenix Warbird), and hire the Cannoneer, you can defeat Captain Crawfish. Sail to the sea near Skullduggery to fight him. Once you win, return to Fort Ridley and the Governor will give you the location of the buried treasure (and a special shovel). Dig up the Buried Treasure on Skullduggery Island to win the game. (see solution at the related question)