Here is the full list of all 17 Buccaneers! achievements.
Complete Act 3.
Complete Act 2.
Fully upgrade a ship.
Have a full fleet of four ships (excluding temporary ships).
Acquire a Three-Decker.
Complete Act1.
Capture any town by defeating its fort.
Choose which faction to join.
Rename a ship.
Have a fleet of two or more ships (excluding temporary ships).
Capture a ship.
Steal a ship from an enemy harbour.
Reach player level 20.
Conquer the Caribbean for Britain.
Conquer the Caribbean for France.
Conquer the Caribbean for Spain.
Conquer the Caribbean for the Buccaneers' League.