Tides are primarily influenced by the orbit of the moon. To show this, the Ocean Tide Clock has an extra (blue) hand, which makes a full sweep of the dial at the lunar rate - about 12.5 hours instead of the normal 12 - indicating the state of the tide for a chosen location. NOTE: because the lunar cycle varies with the Earth's there are times in a month when actual tides are a few minutes ahead or behind the clock.
The Royal Ocean Tide Clock has a Quartz movement, which uses one AA battery. The clock has a two-year warranty.
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