Tide Predicting Machines

Tide Predicting Machines are analogue computers designed to simulate the rise and fall of the ocean tide. Find out more about them and the fascinating history of their use.

Tidal Science explained

Many of us know that tides are linked to movements of the Moon and Sun. But what is the mechanism, and how is it possible to predict water levels at any location?

Visit the exhibition

Tide & Time is open to the public once a month. You can book a visit to see the remarkable Roberts-Légé and Doodson-Légé machines in Liverpool.

Local heroes

Jeremiah Horrocks observed the transit of Venus in 1639 and made tidal measurements at Toxteth, Liverpool in 1640.

Local heroes

William Hutchinson, Dockmaster at Liverpool and former privateer, measured heights and times of high waters during 1764–1793.

Tidal predictions for D-Day

The Roberts-Légé was one of two Tide Predicting Machines used during planning of the Normandy invasion in WWII.