The strange case of the vanishing water …
No crane in the world is strong enough to lift a 20,000-tonne vessel up in the air. Nevertheless, every once in a while, a ship does need to have its underwater hull painted, maintained and repaired. And you can’t really do that while the ship is in the water.
The solution? To make the water around the ship disappear. And that’s done, not with an “abracadabra”, but by using a dry dock. You can see how in the film:
- The dry dock is an enormous basin big enough for a ship to enter.
- The dock is fitted with huge doors, like a canal lock. When the ship has entered, the doors are closed.
- Powerful pumps then drain the dock of water, leaving the ship to rest safely – and dryly – on the dock floor. Now the hull is accessible for work from all sides.
- After work is completed, valves are opened in order to refill the dock with water from the sea.
- When the dock is filled with water again, the ship is afloat and can exit through the opened doors.