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How Tide Clocks Work

At Seaglass and Stiches we've been collecting seaglass from beaches around the UK and Europe for a long time, mainly just for pleasure, but also to create the seaglass pictures which you'll find on our ETSY site. Because of our love of the sea we've become inspired to create individual, hand made tide clocks incorporating seaglass.

You might think a tide clock is a magical device that somehow can tell when the tides will at their lowest or highest; and it may seem improbable that such a device could be truly accurate. However, tide clocks do just this, with some fluctuation that is to be expected. Seaglass and Stitches tide clocks use digital, battery operated tide clock movements, which look very similar to ordinary time clock movements except they tell the tide, not the time. They work because they're based on a Lunar day which is 25 hours and 50 minutes rather than time clock which is base on a 24 hour solar day.

A Seaglass and Stitches tide clock is designed to display High and Low water with 1/6 of a tide markings in between. Each 1/6 marking is roughly an hour, but as you'll see from the text below the clock is based on a lunar cycle, which is slightly longer than a day on a normal time clock. Here's a picture of one of our clocks.

Tide clocks are calibrated to match the lunar cycle, approximately one rotation every 12 hours, 25 minutes. Given that the lunar cycle powers the tides, tide clocks are a simple way of tracking the times of high and low water in a given location.

Tide clocks will have fluctuations throughout the year but will in general be pretty accurate. It’s not recommended to change the time if you notice a discrepancy because it will even out over weeks and months, and adjusting the clock can result in a bigger variation in tide prediction. Most tides are regular enough that a tide clock, once set to your local tide, will be a good indicator of when the tide is coming in or out. It's also worth bearing in mind the tide times are only a prediction and often only accurate to + / - 30 minutes.

You can set your tide clock at any high tide, based on tide timetables, however the best time to set it is high tide 'springs' which is full moon or new moon. The tide timetables, which you can find online, will tell you when a full or new moon is.

A tide clock will work anywhere that has a regular tide, called a Diurnal Tide, which has two tide cycles each Lunar day. That all sounds a bit technical but if the tide looks like this then it's Diurnal.

There are a few tides which don't behave this way such as the Solent in the South of England, but it's very obvious when you look at the graph of the tide. If you're not sure we can help.

The Tide Clock is a lovely addition to a house near the sea, it's useful to anyone who enjoys the beach and the sea, and is especially useful where the beach is swallowed up by the sea at high tide.

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