Just a thought:
The old sea-dog tavern area at the center of the map. Let's open the inside of the tavern, and make it a pirate gambler's den.
Bring your loot, and stash it with the house. (You get full-credit, but no emissary bonuses with it.) Then, pirates can take their ship to the gambler's house and wager with what they have at the house. Liars dice, card games, etc. We've seen examples at the taverns in the game that these gambling games exist. All winnings and losses come from hour house stash, not your regular doubloons.
Your money is SAFE in the sea dog tavern, but is separate from your gold stash. To add to your coins, you have to "cash out" at which point you are given an item, say a "Cash-out box" that has to be traded in with an Tavern Keeper at one of the regular outposts.