What you do is you can pick up cargo that is floating around in the water. If you cant find very much, or monsters and ships keep attacking you, here are some tips:
at Bouffant Bay, sell silk, and buy medicine.
at Parrot Port, sell medicine, and buy spice or silk.
at Golden Harbor, sell spice or silk, and buy grain.
at Pirate Outpost, sell grain and buy spice.
at Dragon Cove, sell spice and buy silk.
As you can see it goes in a circle. You don't really need to do it twice, so at Dragon Cove, you should just sell all of your cargo.
keep trading
trade and salvage
This is a long process (at best 3 to 5 hours of play). There are no shortcuts.(see related question)
you can buy it at dragon cove for 1000000 doubloons
You can get doubloons by sinking other ships, monsters and by selling cargo.
The way I got doubloons was to search the ocean find ship wrecks and get all the cargo and doubloons that were on the ship.
Earn 500,000 doubloons then get a loan at Golden Harbor at the bank .Or you can as many as Grains as you can then sell it at Pirate Outpost until you get 1,000,000 doubloons.
You sell the resource that is worth the most at one trading post and also buy the cheapest, then continue doing that in a clockwise circle. If you have all the crew members and a good ship, you can attack pirates and sea creatures.
Start from any island. Buy things at the lowest price like when they are 14 doubloons. Sell things at the highest price like when they are 32 doubloons.
You get a larger ship by having a lot of doubloons and then go to dragon cove and buy and new ship. Hint the cheapest ship is 3000 doubloons and the most expensive is more than 30000 doubloons.
the cannoneer is 20,000 doubloons.
yes and no yes if you play the game for a month with the next boat no you will not be handed a million dalblons i beat the level in three hours what you do is buy each ship that after the first one and not just the last one