*This achievement is currently "buggy" for some and may not unlock*
This is for simply completing a "Gold Hoarder" voyage!
In order to do that head to an Outpost location and the Gold Hoarder shop is a little purple tent somewhere usually along the beach.
Go up to the Hoarder select the first chat option and grab a voyage.
Head back to your boat and go to the table and propose voyage, vote on voyage, and then go do voyage.
Once completed you *might* unlock the achievement!