Fergus Hall

The title Three Hours After High Water refers to a section of a tidal flow atlas which illustrates the tidal flow at various points six hours before and six hours after the high tide. Arrows of different sizes indicate the approximate intensity and direction of the tidal flow within a given region. The numbers refer to the speed in knots during a neap tide (the number before the comma) and a spring tide (the number after the comma), each of which is dependant on the phases of the moon.

I came across examples of tidal flow atlases while researching tides. They were beautiful maps with their flowing arrows that bend and swirl around landmasses which have been shaped by the tide over millions of years. The west coast of Scotland in particular has incredibly intricate tidal movement owing to its abundance of islands, sea lochs and rugged underwater topography (known as bathymetry). The resulting tides are interwoven, fast and often dangerous, circulating around landmasses like an intricate system of arteries.

The tide itself is two colossal waves created by the pull of the moon which travel around the earth as our planet rotates. It is like the earth inhaling and exhaling, each lasting around six hours and circulating nutrients throughout the ocean, removing eroded sediment and helping to regulate the earths temperature. The seas around the west coast of Scotland support a high level of biodiversity as a result of its intricate tidal system.