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Créac'h lighthouse seeks its next technical revolution
One hundred and sixty-two years after it was commissioned, the Créac'h lighthouse on the west coast of Ushant Island remains an emblematic landmark for all sailors along the shores of the Iroise Sea. With its double Fresnel lens weighing 17 tonnes, its range and power are among the greatest in Europe. But beneath the beauty of this optical feat lies a mechanism more than a century old, now under surveillance: the mercury tank used to turn the optics.
This technology, as ingenious as it is toxic, is gradually being phased out across the entire French lighthouse network. At several âeuros sites, such as the Sept Ãles âeuros, mercury removal operations have already been carried out successfully. For Créac'h, the operation promises to be more complex. The weight of the optics, preservation of the original mechanisms and the need to maintain signal quality make the equation a delicate one.
A call for expressions of interest open to the maritime community
Faced with this challenge, the Direction Interrégionale de la Mer (DIRM NAMO), in conjunction with the Pôle Mer Bretagne Atlantique, has launched a call for expressions of interest (AMI) open from December 22, 2025 to March 22, 2026. The objective is clear: to identify solutions for replacing the mercury while preserving the lighthouse's heritage and guaranteeing the continuity of the maritime signalling service.
The challenge was more than just a technical replacement. It also involves respecting the listed nature of the site, preserving the Fresnel lens in its current state, and ensuring the stability and regularity of the optical rotation. Several approaches could be combined: mechanical adaptation, bearing innovation, partial automation, or even hybrid solutions between preservation and modernization.
A call for collective intelligence, well beyond the maritime world
This project goes beyond the boundaries of maritime administration. The call is addressed to engineers, architects, researchers, schools, industrialists and heritage specialists, as well as to the sailors and technicians who work alongside these granite giants on a daily basis. It's a collective effort, as much heritage as technical, to invent a tailor-made solution for this extraordinary lighthouse.
Often forgotten, sometimes relegated to a purely symbolic status, these structures nevertheless continue to play an active role in navigation safety. The transformation of Créac'h could thus become a pilot project for other lighthouses in the network still equipped with mercury mechanisms.
Responses are expected by March 22, 2026. The call for expressions of interest is available online (link at the foot of the article), and proposals will be evaluated according to their technical feasibility, their compliance with heritage requirements, and their ability to ensure continuity of maritime service.
