The Largest Ship Lock in the World
The Three Gorges Dam Project holds many world records. One of the most impressive is the world's largest ship lock. The Three Gorges Dam's Five-Stage Ship Lock can raise or lower ships to cross the Three Gorges Dam. Essentially, it is a giant ship elevator. It is capable of lifting a passenger line or cargo ship of 14,000 tons to a maximum height of 113 meters. Last year alone, this ship handled over 40 million tons of cargo. It is estimated that by 2010, its volume will rise to 60 million tons, and to over 100 million tons by 2020. This is due to the economic boom in China's western region. Because of the giant ship lock, a ship can pass through the dam in about forty minutes.
Three Gorges Dam
The design and construction of the ship's lock were exceptionally difficult. Because a ship would have to be raised or lowered over 100 meters, the water pressure is enormous. There is no existing gate that can withstand such pressure.
In order to solve the ship lock designers designed five locks, instead of one. This way the water pressure is greatly reduced. Each lock raises or lowers a ship approximately 20 meters. The entire process takes over half an hour. The basic idea behind a ship lock is actually quite simple. When lowering a ship a ship is moved into a watertight compartment called a lock. The gate is closed behind it, and the water in the compartment is released into the next watertight compartment, which is lower than the first. As the water is released the ship is lowered. When the water level in the ship's lock is the same as the next lock's a gate opens between the two locks and the ship is moved forward into the next lock. The door is closed behind it and the process repeats itself until the ship has been lowered to the level of the river. Raising a ship is essentially the same, but instead of releasing water to lower the ship, water is pumped into the lock to raise the lock.
The Three Gorges Dam's Five Stage Ship Lock is truly a modern marvel. It is just one of the many world records held by the Three Gorges Dam that you'll meet on your Yangtze cruise.