Here is the full list of all 31 Windward achievements. It takes around 40-50 hours to unlock all of the achievements on Windows.
Opt out of a PvP match by using a White Flag.
Find and equip your first epic item.
Drop Grogolov on top of 3 or more enemies.
Completely drive out pirates from a level 9+ region.
Defeat an enemy by yourself without taking any damage.
Establish a foothold in a region where your faction has no towns.
Repair your ship while obscured by fog.
Defeat 100 ships.
Hire a follower.
Defeat a Pirate Captain.
Successfully complete a commission to place a Guard Tower near a town.
Complete 50 commissions.
Defeat two enemies back to back.
Become a true pirate. Arrr!
Achieve a skull kill rating.
Upgrade your ship.
Defeat 5 pirates.
Make a town grow in size.
Open a Sealed Letter.
Customize your ship's look.
Do your first trade run.
Complete two consignments at the same time.
Complete your first commission.
Unlock all ships.
Equip an item that will push any stat above 1000.
Capture a level 9 or higher region in a co-op match.
Sink a pirate captain in a level 39+ region.
Sink another player in PvP.
Drive out pirates from a level 39+ region.
Achieve the Admiral reputation standing with any faction.
Complete the Strange Diagram quest.