Tidal mills worked in a similar manner as watermills but used the rise and fall of the tide to power the water wheel rather than the water flow on a stream or river.
A mill pond, alongside the mill, would be filled by the incoming tide through a sluice gate which was then closed at high tide. As the tide fell, the trapped water was then allowed to flow back through the mill wheel.
The inlets on the northern coast of the island proved ideal for such mills - from the late 18th century, up to eight tidal mills were in operation.
Some mill ponds were also fed by streams which increased the volume of water used to power the wheel; other mills (St Helens and Freshwater) depended entirely on the water trapped from the tide.
Today, (2016), there are no tidal mills operating on the island - some the mill buildings and ponds remain at St Helens and Freshwater (although at St Helens, the house on the site is significantly different from the original building).