The Mill

at Tide Mills

Where it began
Building the mill
What is a tidal mill
The moon and tides
The power of the sea
How the mill worked
The mill in numbers
William Catt
The death of the mill
Renewable energy today
Illustration of William Catt with the Mill behind

Where it all began:

In 1761, the Duke of Newcastle gave local corn merchants permission to build a Tide Mill in Bishopston, Sussex.

Evidence:This image shows the first page of the private parliamentary bill that granted permission. How much of it can you understand?

Image courtesy of Newhaven Historical Society

Building the mill

The first job was to create an island in the creek where the Tide Mill was to be built. It was a big task, especially as they had no machinery like we have now! Instead, the workers would have used hand tools and worked very long days in all weathers.

Although a sewage survey in 1766 mentions the Tide Mills building, the first proper siting is on a French spy map dated 1768, on which the new multi storey building was mistaken for a military barracks! During this time war with France was never far away…

It took 7 years from when permission was granted for the new Tide Mill to be finished in 1768 and another 4 years before the owners got the mill working – that’s 11 years in total!

Take a look at these images of the Mill…

Question Can you imagine building something so big without modern machinery?

  • Wheel

What is a tidal mill?

A Tidal Mill uses the power of the tide going in and out to turn water wheels. The water wheels then turn big mill stones to grind wheat or corn into flour.

Flour is an essential ingredient in most baked goods like bread, cakes and biscuits.

Using the tides to generate power is an example of clean (sustainable) energy.

Question:Do your favourite biscuits have flour in them?

The moon and tides

The gravity of the moon pulls ALL the oceans and seas of the earth towards it like a magnet, making two “bulges” of water. As the earth spins, these bulges of water create what we know as “tides”, where the water level rises and then falls.

  • Moon
  • Earth
  • Tide
  • TideLabels
  • Gravity

Because the Earth rotates through two tidal “bulges” every lunar day, coastal areas experience two high and two low tides every 24 hours and 50 minutes. High tides occur 12 hours and 25 minutes apart. On average, it takes 6 hours and 12.5 minutes for the water at the shore to go from high to low, or from low to high.

The power of the sea

Tides are very powerful. Benner Bay is on an island in the Caribbean Ocean and is shaped like a funnel. The tide can easily raise over 13 metres from low tide to high tide.

In one 12 hour tidal cycle, about 110,000,000,000 short tons (100 billion tonnes) flows in and out the bay, which is twice as much as the combined total flow of all the rivers of the world over the same period. The water movement is as powerful as 8,000 train engines or 25 million horses!

The tide is powerful.
The tide at Tide Mills can easily raise over 5 metres from low tide to high tide.
QUESTION How much water do you think used to move through the 3 water wheels at Tide Mills?

How did the tidal mill work?

The Mill used a large lagoon to catch the water at high tide. When the tide went out, a sluice gate was opened and the trapped water poured down through 3 water wheels. The turning of the water wheels provided the power to turn the mill stones used to grind the grain.

Mill Diagram Coloured

Sluice gate: A sluice gate is a type of big gate to stop the water. It would have allowed the workers to control the flow of the water from the lagoon through the mill. 

Tidal Lagoon: As the tide came in, this reservoir would fill with water ready to power the mill when the tide turned.

Water Wheel: There were three water wheels at Tide Mills. As the water flowed from the tidal lagoon back into the creek it would turn the wheels, powering the mill.

Creek: The Mill was built upon the old path of the River Ouse. The river now flows into the sea in Newhaven, but originally flowed parallel to the beach and into the sea at Seaford. Water would flow in and out of here as the tide rose and fell – you can still see this happening today!

The Mill: The Mill building sat above the water and almost nothing remains of it today.

Click on each image to learn more about how the mill works...

There are two high tides a day so this process would happen twice a day, or every twelve hours twenty five minutes to be more precise! The times on these pictures give you an example of one tidal cycle.

The villagers who worked at the mill would work to the natural times of the tides. At its peak the mill could produce…

sacks of flour per week
tonnes of flour per week
0 +
sacks of flour per tide

It was extremely hard work. The Mill would be working between 16 and 20 hours a day, every day, every month, every year.

  • Flour

William Catt Mill Owner | 1808 - 1853

  • Catt
William Catt took over the Mill in 1808.

He expanded the power of the Mill and built a village for his mill workers. He increased the number of grinding stones from 5 to 16 pairs and over 60 villagers worked in the mill at this time.

Can you guess what else Catt added at Tide Mills?

Hover over each picture to find out...

A Blacksmith’s Forge

For making and repairing things with metal


A Carpenter’s Workshop

For working with wood


A new office building and a granary

A granary is a storehouse for threshed grain


A School

To educate the children of the mill workers

Harnessing the wind

Despite being a tidal mill, you might have noticed a windmill in many of the pictures of Tide Mills. This was another of William Catt’s additions.

He added the windmill on top of the mill to power a sack hoist – a type of lift for moving the sacks of grain between floors. Using the wind is another example of how the mill relied upon clean (sustainable) energy!

William Catt was a tough boss who worked his workers extremely hard. He died in 1853. His son, George Catt, took over the running of the mill.

After his death, this is what was said about him:

“Few men so long a career ever wielded a more powerful and useful influence in a neighbourhood, than the deceased in this part of England … The well known mills at Bishopstone became so influential under his direction as to govern the flour trade in the South of England ….”

QuestionWhat do you think this means?

The death of the mill

The arrival of steam power transformed the milling industry and was one factor that led to the decline of the Tide Mill. Steam power is produced by burning coal – a fossil fuel – that isn’t good for the planet.

The building of the railways also meant it was cheaper and easier for farmers to send their grain directly to big cities like London to be milled. On top of that, severe storm damage in 1875 reduced the Mill’s output and, under the control of the less pioneering George Catt, the Mill limped on for only eight more years,

The Mill closed in 1883 and was used as bonded warehouses until it was pulled down in 1901.

  • Turbine
  • Turbine

The Tide Mill used the natural power of the tide and wind over 200 years ago but most of the UK’s energy now comes from unsustainable sources like coal, gas and nuclear power. In 2020, the UK is aiming to meet a target of 30% of energy being produced from sustainable, environmentally-friendly sources.

The Rampion Offshore Wind Farm can now be seen from the beach at Tide Mills. This is a modern-day example of sustainable energy.

Question What do you think we could learn from Tide Mills? Do you think we use enough wind and tidal power today?

The Mill at Tide Mills was an early example of using natural power to make things work. In many ways, it was way ahead of its time.

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