Here is the full list of all 15 Don't Sink achievements.
Lost to the seas only you can find him. Rumor has it he is somewhere in the main menu!
Purchase the Man of War.
Defeat 25 pirates at sea!
Build Cramton to completion starting from nothing.
Capture and own 6 islands at the same time.
Complete at least 50% of all available quests.
Complete a sea voyage that is at least 2,000 miles in distance.
Travel a total of 20,000 miles by sea.
Spend 25,000 gold!
Try to capture the ferret captain!
Complete the side quest, "Tough Decisions"
Capture an island!
Purchase a better ship.
Complete a sea voyage that is at least 1,000 miles in distance.
Begin your journey!