Here is my video playthrough of the final part of the game, with all the achievements, including this one.
1. Once you get stopped by an iceberg, you'll go underwater, and enter a structure.
2. Go to the bottom and fill up water canisters, and drag them to the far left to level the building.
3. Use the lever to attach the pipe on the left side, keeping the building level.
4. Grab the repair tool that appears, and fix the elevator shaft.
5. Upon using it, your boat will be sent away.
6. Follow to the right, until you exit the building, and swim to the surface, unlocking the achievement.