How did John Smeaton’s design change the construction of offshore lighthouses?

John Smeaton revolutionized the construction of offshore lighthouses by introducing advanced engineering techniques that became the standard for wave-swept structures.12

His design for the third Eddystone Lighthouse (1756–1759) introduced several critical innovations:

• Interlocking Masonry: Smeaton utilized dovetailed blocks of stone, which locked together to provide superior structural integrity against the force of the sea.23
• Curved Profile: Rather than a straight taper, he designed the tower with a curved profile. This shape helped dissipate the energy of wave impacts by directing the water to sweep up the walls rather than striking the structure with full force.3
• Hydraulic Mortar: Smeaton identified that limestone with a high proportion of clay created the most effective hydraulic lime for underwater construction, ensuring the foundation could withstand constant exposure to the ocean.2

By relying on the tower's own weight for stability and employing these sophisticated building methods, Smeaton established the foundation for modern offshore lighthouse engineering.3