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This dual lift is the tallest hydraulic boat lift in the world, raising and lowering boats 65 ft
(19.8 m). Conventional locks typically provide only a 7 ft (2 m) change in elevation.

This design of hydraulic lift needs no external power, functioning by gravity alone using a
counterweight system. The concept can be likened to a giant scale comprised of two chambers.
An extra few inches of water added to the upper chamber is enough to tip the balance and when
the crossover valves are opened, the upper chamber begins to descend which forces the lower
chamber to rise. The weight of the boats in the chambers is irrelevant because each boat
displaced its own weight in water before the gates of the chambers were closed.

Photographed in Peterborough, Ontario Canada.