Brass Nautical Porthole Tide Clock 117mm OA (18029)

• Back Flange Diameter 117mm
• Face and Dial Diameter 79mm
• Depth 52mm
• This instrument should be used with caution and is only intended as an aid to navigation.
• The Porthole Ships Nautical Channel Range of Instruments is made of solid laquered brass with a porthole opening latch and bevelled glass.
• The Tide Clock features a quartz movement and an additional hand which records lunar time over a 24 hour 50 minute period and so indicates successive high and low tides.

Explanation of the use of the tide clock

The tide indicator hand should be set to high tide when the next high tide in your location occurs. The exact time of the next high tide can be obtained from official tide tables. As a general rule the best time for setting the tide hand is at high tide during a new or full moon. If it cannot be set during a new or full moon then we recommend checking it at that time during the next cycle. The tide clock is not a perfect predictor of high and low tides during a moon phase, however at the same location and at successive moon phases it is surprisingly accurate.