Lift lock

A boat lift, ship lift, or lift lock is a machine for transporting boats between water at two different elevations, and is an alternative to the canal lock and the canal inclined plane.

It may be either vertically moving, like the ship lifts in Germany, Belgium, the lift at "Les Fontinettes" in France or the Anderton boat lift in England, or rotational, like the Falkirk Wheel in Scotland.

The first known boat lift was a 2.5 ton tub boat lift on the Churprinz mining canal in Halsbrücke near Dresden. It lifted boats 7 metres without the use of caissons. The lift operated between 1789 and 1868. For a period of time after the opening of the Churprinz lift boat lifts were of an experimental nature with the engineer James Green reporting that 5 had been built between 1796 and 1830. He credited the invention to Dr James Anderson of Edinburgh.Erasmus Darwin's Commonplace Book dated 1777–1778 includes a design for a canal lift based on balanced water filled caissons on page 58-59

An example of these early lifts was the one constructed at Mells on the Dorset and Somerset Canal. Lifts on the tub boat section of the Grand Western Canal entered into operation in 1835 becoming the first non experimental boat lifts in Britain.

1904 the Peterborough Lift Lock designed by Richard Birdsall Rogers opened in Canada. The lift system is operated by gravity alone, with the upper bay of the two bay system loaded with an additional 30 cm of water as to give it greater weight.

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