A Ships Tide Clock

A tide clock is a specially-designed clock that keeps track of the Moon's apparent motion around the Earth. Along many coastlines the Moon contributes the major part (67 percent) of the combined lunar and solar tides.
Tide clocks keep an approximation of the average time between high lunar tides: 12 hours 25 minutes per revolution. As the precise average time between high lunar tides is actually half of a lunar day, or 12 hours 25 minutes 14 seconds, tide clocks gain about 15 minutes per month and must be reset periodically.

Brass dials mounted on wooden plynth with clear tidal markings. High and Low water AM and PM.

Dimensions. 11in 28cm width 6in 15cm height 1kg weight.