Matey get out there and sink ships. Then when you think you've sunk a lot of ships, go sink some more
Sail with someone that has 5 skill points in treasure sense, more royals will drop. Also go sink the warlord that's off of devils anvil. It spawns a lot, you can make a lot of gold there. But make sure your captn has points in treasure sense.
goold luck getting your war frig