Tide Clock

From the website:

Tide Clock

For tide indication simply set the hand to the full tide position at time of high tide for your location — the quartz-driven hand will rotate every 12 hours and 25 minutes, indicating approximate tidal state.


How a tide clock works:

Tides are caused mainly by the moon's gravitational pull on the Earth.

The time it takes the moon to reappear at the same place in the sky each day is 24 hours and 50 minutes.

This is called a lunar day.

Many areas in the world have semi-diurnal tides (two high tides and two low tides a day).

The tide clock is designed to rotate twice each lunar day (every 12 hours and 25 minutes), giving you a quick and easy indication of high and low tide.

Other influences on sea levels and tide times which must be taken into account:

• The sun's own gravitational pull when lined up with the moon

• Changing volume of river flows

• Strong on / off shore winds

• Atmospheric pressure


Features:

• Hand-spun stainless steel

• 7-11/16" Ø (195 mm)

• Quartz movement

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Tide and Time Clock below.

$58.95.