A wave-proof mini-Fort Boyard in Belgium

The scene takes place in a research centre in Ostend (north-west), which has taken on the dimensions of a hangar to house a wave pool. In the middle of this pool stands a mini-Fort Boyard made of concrete.

Scaled down to one-thirtieth of its actual size, the model is a very close replica, with the fort's rounded ends and its openings precisely spaced apart, over three floors.

Solidity, structural stability, resistance to erosion and submersion: the tests carried out by these Belgian specialists in coastal and maritime engineering are part of the major renovation planned for 2028.

They were approached by the French public works firm ETPO (Spie Batignolles group), involved in this adventure with the French department of Charente-Maritime, owner of the site.

Their particularity is to be based on a 3D replica of the building studied, something rare in the practice of researchers.

"Normally we use 2D models, with simplified geometric shapes for cost reasons. Here it's great to have the fort in our basin and to contribute to this renovation of a historic building," Peter Troch, one of the leaders of the research project, explained to AFP.

"We generate storm waves in real conditions and these tests will make it possible to improve the initial design of the fort, as it was conceived for this renovation. It is a form of validation of the project before the start of the work", continues this professor from the University of Ghent, who is one of the partners of the Ostend centre launched in 2023 (the Coastal & Ocean Basin, COB).

The climate change factor

A significant part of the work concerns the two ends of the fort, where the project foresees the reconstruction of the protective works which have disappeared over time, swept away by the assaults of the ocean.

At the front, there is the spur pointing its nose towards the open sea, to the northwest, and at the back, the port - or "landing haven" - through which visitors will be able to disembark from 2028 in favorable weather.

Around the wave pool, technicians monitor the data sent back by sensors in the water on screens, and their attention is focused on the breakwater wall placed at the front on the spur. And how well it is able to protect the building from the action of the swell.

"With climate change we are not sure what sea conditions we will have in the future," emphasizes one of the specialists from Ghent University.

"If we can mitigate the energy of the waves that propagate, we also limit erosion, which was the major factor in the degradation of the fort," she adds.

Built between 1803 and 1857, a former military structure that became a prison between the island of Oléron and the island of Aix, Fort Boyard had fallen into disrepair before being listed as a historic monument. Bought in 1988 by Jacques Antoine, a television game show producer, it was sold the following year to the Charente-Maritime department for a symbolic franc. The latter was responsible for maintaining it.

Currently inaccessible to the general public, the building continues to host filming of the game show that made it a global star every spring - from March to the end of June. The show "Fort Boyard", launched in 1990 in France, has given rise to more than 1.500 episodes in around forty countries.

The renovation work, which is due to start this summer, has been estimated at 36 million euros excluding tax. Three-quarters of this sum has already been financed. And to find the remaining nine million, an appeal for donations was launched in mid-December, counting on the strong reputation of the place.