User:Geo Swan/Chinese ship lifts

The government of China has built or is building several new Chinese ship lifts.

Ship lifts, also called boat lifts or lift locks, are an alternative to canal locks. Unlike a canal lock a ship lift has an entire basin, or caisson, that the vessels enter, then water-tight doors close, and the ship lift raises or lowers the entire basin.

While the ship lift at the Three Gorges Dam, the largest in the world, is China's most famous, China has many mountain ranges, and some of the highest dams in the world, and ship-lifts were well-suited to enable navigation of the upper rivers behind those dams.

Ship lifts have several advantages over the much more common canal lock, for navigation. Ship lifts have the advantage of not sending water downstream, when a vessel transits the mechanism; and can be considerably faster, when transiting a large vertical distance.

was designed to lift vessels of up to 3,000 tons displacement. The vertical distance traveled will be 113 metres. The size of the ship lift's basin will be 120x18x3.5 meters.

The ship lift, when completed, will take 30 to 40 minutes to ascend or descend, as opposed to the three to four hours for stepping through the main locks.

In the original plans the ship lift was going to have the capacity to lift vessels of up to 11,500 tons displacement.

Most of the dam was completed on May 21 2006. But the ship lift was not yet complete. China Daily predicted, on October 3 2006, that the shiplift wouldn't be completed until 2008.

One of the complicating factors the design has to deal with is that the water level can vary dramatically. The ship lift had to be designed to work properly even if the water levels that varied by 12 meters on the lower side, and 30 meters on the upper side.

Other Ship Lifts
The Chinese government has built several other ship lifts, of lesser capacity,
 * 1) There is a ship lift at the Geheyan dam, in Hubei Province, capable of lifting vessels of 300 tons displacement. The dam was completed in 1994, but technical difficulties delayed the opening of the ship lift for four more years.
 * 2) There is a ship lift on the Danjiang River, at the Danjiangkou dam, also in Hubei Province, capable of lifting vessels of 450 tons displacement.
 * 3) There will be a ship-lift on the Longtan dam on the Hongshui River, a branch of the Pearl River, in the Guangxi Zhuang Autonomous Region. The Longtan ship lift has the capacity to lift vessels of 250 tons, in a basin 40×10.8×1.8 meters, and a vertical lift of 68.5 meters.