From publisher blurb:
Treasure of Shipgrave Reef is a 4-hour adventure set in the world of the Aethereal Expanse, a setting from Ghostfire Gaming. This version of Treasure of Shipgrave Reef is made specifically for use with the Black Flag Roleplaying System, but it works with any 5e-compatible game with just a few tweaks by the game master.
Treasure of Shipgrave Reef is the first part of a complete campaign-length adventure called Pirates of the Aetherial Expanse published by Ghostfire Gaming. This Black Flag Roleplaying System conversion you are now reading comprises just the introductory first episode in that larger campaign.
The Aetherial Expanse setting is perfect for telling the story of pirates and empires seeking fortune, glory, freedom, and dominance upon the starlit seas of the Astral Plane.