Here is the full list of all 10 Submerged achievements. It takes around 4-5 hours to unlock all of the achievements on Windows.
Finish the campaign
Gather all secrets
Stay in the boat for a complete Day/Night cycle
See all creatures
Gather all boat boosts
Visit all landmarks
Visit all of the hotels
Use the postcard feature
Climb to the highest point in the world
Visit the n/e/s/w boundaries