The building of the Eddystone Lighthouse is undoubtedly the project that made John Smeaton famous. His iconic design was the third lighthouse to stand upon the small but dangerous Eddystone Rocks 13 miles off the coast of Plymouth. The previous two structures had not fared well. Henry Winstanley’s ornamental tower built in 1698 was washed away in the Great Storm of 1703. The second tower, built by the architect John Rudyard, was constructed from timber and had a longer life than its predecessor. Rudyard’s lighthouse lasted an impressive 47 years until 1755 when the lantern room caught fire and the tower was destroyed by the blaze.
At the time of the blaze the Eddystone Rocks were leased to a syndicate of businessmen led by Mr Robert Weston. The syndicate was keen to commission a replacement lighthouse as quickly as possible and Robert Weston sought advice from the Royal Society about a suitable engineer for the project. The Royal Society put forward the young engineer John Smeaton who was at that time working in Northumberland. The recommendation came with such high regard that John was not required to submit a proposal or compete with other engineers for the work. He was simply told by Robert Weston ‘Thou art the man’ which John took to be a great honour.
Being held in such esteem by his contractors gave John the confidence to present a radical new design for the lighthouse - one that was built into the rock itself and made from granite and Portland stone. Not only would it be made of robust and inflammable stone, but the shape of this new lighthouse would include a sweeping curve at the base of the tower that would act to dissipate the energy of the waves.
This ingenious shape was inspired by the tree trunk of the mighty oak tree which, John had observed, withstood ferocious gusts of wind thanks to its heavy base and low centre of gravity.
The method for securing the huge granite blocks together was an important part of his oak tree inspired design. This was achieved by mimicking the dovetail joints that John had seen on the kerbstones of London’s pavements. Carving dovetail joints into the granite blocks allowed them to be securely slotted together and gave the lighthouse the solidity and flexibility it needed to prevent even the most violent of waves from causing damage.
Construction took place over three years in challenging conditions out to sea and required creative problem solving and management throughout the build. Heavy granite blocks, hoist machinery, tools, food and equipment all had to be transported to the treacherous rocks by boat.
“meeting the slope of these rocks, the sea breaks upon them in a frightful manner, so as not only to obstruct any work being done upon the rock, but even the landing upon it, when, figuratively speaking, you might go to sea in a walnut shell” John Smeaton: The Building Of The Eddystone Light
Cement was needed to fix the stones together but traditional mortar was difficult to apply in such wet conditions. In response to this problem John devised a form of waterproof cement called ‘hydraulic lime’ which would set underwater.
Smeaton's lighthouse was 72 feet (22 m) high and had a diameter at the base of 26 feet (8 m) and at the top of 17 feet (5m). It was lit by a chandelier of 24 large tallow candles and completed on 16th October 1759. John was on board a boat seven miles away at sea to watch the first lighting of the tower. He was not disappointed with the results and wrote:
“We were about seven or eight miles distant from the house at the first lighting this evening. The light at first appeared very strong and bright to the naked eye, much like a star of the first magnitude. Its lustre diminished as we increased our distance, till it came down to a star of about the third magnitude. After this it ceased to diminish, and, on the contrary seemed to increase. This I could not but wonder at.”
It seems that the rest of the world also looked upon the stone lighthouse with awe and wonder and, in the following years after its completion, visitors would flock to Austhorpe in Leeds to view John’s working model of the tower. So many people asked to come and view the model that John was unable to personally keep up with demand and so delegated the visits to his wife Ann who was so familiar with the work that she was able to fully explain the construction of the tower.
In Plymouth the lighthouse remained operational and structurally sound until 1882 when it was decommissioned. The reason for dismantling the lighthouse was due to erosion found on the rocks but the lighthouse itself had remained intact for 123 years.
Over this time it had become such an iconic emblem for the people of Plymouth that a successful campaign led to the tower being rebuilt, using the original upper sections of the lighthouse, on Plymouth Hoe.
It still stands there today and the remaining base of the lighthouse can be seen, still clamped firmly to the Eddystone rocks.
