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