Demonstration — why a conventional tide clock drifts over time

A conventional tide clock runs at a fixed rate, one turn every 12 h 25 min 14 s. The real tide does not: its times shift a little every day. The gap builds up, and within a few weeks a conventional clock can show the wrong phase of the tide altogether.

The Connected Tide Clock resynchronises itself on the CNES predictions. Drag the slider to watch the drift build day after day. For actual tide times and forecasts, go to the Tide times page.