Seasoned Pirate

As someone who has spent a lot of time on ships, you have Advantage when making checks related to ships/sailing.  You also have Advantage on Survival checks that relate to navigation by the stars.

You have a tattoo on your forearm that identifies you as a pirate. All pirates have this tattoo. You have Advantage with Persuasion checks when talking to sea-faring folk (sailors, ship captains, harbormasters etc), UNLESS they see your tattoo, in which case you have Disadvantage. However, if you are talking to another pirate and show them your tattoo, you have Advantage in Persuasion checks with them.