Where can you get lots of doubloons on Skullduggery Island?

Answer 1

You start with none. You find your first doubloon under the covered bridge (cross the river right to left), but you spend it on chicken feed for the boy's chickens.

Once you begin sailing among the islands, you find "salvage" floating in the water, especially above Dragon Cove and between Parrot Port an Golden Harbor. Sinking ships and sea creatures generates a lot, but is risky. Most doubloons will be made by trading -- buying the goods where they are cheap and selling where the price is higher.

(see related question)

Answer 2

There is no practical upper limit. Sinking ships or creatures with a large ship such as the Steaming Fury or Phoenix Warbird generates hundreds of thousands of doubloons per shipload. The likely "field limit" would probably be in the billions, more than anyone could possibly obtain even spending several weeks or months on the game.

Answer 3

You can get some by collecting salvage, especially around Dragon Cove. But once you have a ship with a cannon or two, you can sink sea monsters there and get lots of salvage from them. Of course, it is risky, because the monsters can gang up on you or pirates may also attack.