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. It may be vertically moving, like the Anderton boat lift in England, rotational, like the Falkirk Wheel in Scotland, or operate on an inclined plane, like the Ronquières inclined plane in Belgium. HistoryA precursor to the canal boat lift, able to move full-sized canal boats, was the tub boat lift used in mining, able to raise and lower the 2.5 ton tub boats then in use. An experimental system was in use on the in Halsbrücke near Dresden. It lifted boats 7 m (23 ft) using a moveable hoist rather than caissons. The lift operated between 1789 and 1868, and for a period of time after its opening engineer James Green reporting that five had been built between 1796 and 1830. He credited the invention to Dr James Anderson of Edinburgh. The idea of a boat lift for canals can be traced back to a design based on balanced water-filled caissons in Erasmus Darwin's Commonplace Book (pp. 58–59) dated 1777–1778 In 1796 an experimental balance lock was designed by James Fussell and constructed at Mells on the Dorset and Somerset Canal,