Lift lock

(CC) Photo: Jean-Pol GRANDMONT
Strépy-Bracquegnies shiplift, said to be the largest shiplift in Europe.

Lift locks, also known as ship lifts or boat lifts, are an alternative to conventional canal locks.

Lift locks are a kind of elevator for vessels. In operation, vessels proceed from a river or canal into a basin or caisson, doors then close, and the entire basin is raised or lowered. When it reaches the level of the other section of the canal or river doors open, and the vessel can proceed on its voyage.

Among the advantages lift locks hold over traditional canal locks are that a single lift lock can raise vessels over a vertical distance that would require multiple canal locks. Conventional canal locks require using large amounts of water, because the entire lock has to be filled every time a vessel traverses the lock. Most lift locks do not require moving water from the upper level.

Many lift locks use a pair of counter-balanced basins. Some of the larger lift locks, like the shiplift at the Three Gorges Dam, in China, and the shiplift at Strépy-Thieu in Belgium, on the other hand, have just a single basin, counter-balanced with a conventional counter-weight, like a regular elevator.

Notable lift locks - ordered by size

location	displacement	dimensions	vertical lift	cycle time
Three Gorges Dam, China	3000 tons	280 x 35 meters x 5 metres	113	30-40 minutes (planned)
Strépy-Thieu, Belgium	1350 tons	73.15 metres	112 x 12 metres x 3.35 metres	7 minutes
Scharnebeck, Lüneburg, Germany	1350 tons	105.4 x 15.8 x 3.4 metres	38 metres	3 minutes
Peterborough, Ontario	1300 tons	42.7 x 10.1 x 2.1 metres	19.8 metres	10 minutes
Kirkfield, Ontario	1300 tons	42.7 x 10.1 x 2.1 metres	14.9 metres	10 minutes
Falkirk Wheel, United Kingdom	600 tons	-	35 metres	4 minutes
Danjiangkou dam, China	450 tons
Geheyan dam, China	300 tons
Longtan dam, China	250 tons	40×10.8×1.8 metres	68.5 metres	claimed to be the "fastest ship-lift in the world"
Anderton Boat Lift, United Kingdom	250 tons	22.9 x 4.7 x 2.9 metres	15.25