Post for a Pirate

Location
On Azura Island, talk to Ol' Bristles, sitting at the bar of The Tiny Tavern.

Part 1

 * 1) Ol' Bristles will hand you  to deliver to Captain Blackbrows.
 * 2) Head to Ramshackle Reef on the other side of the island, and climb the large structure built around the rock, on the small island across the bridge.
 * 3) Speak with Captain Blackbrows in his ship at the top of the structure and hand him the letter.