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Origin and history

The Collignon dyke, 1,847 metres long, is a key component of the Cherbourg artificial harbour, the second largest in the world after Ras Laffan. Its construction, begun in 1890 and completed in 1894, had two objectives: to protect the harbour from the incursions of torpedoe ships and to prevent the silting caused by the erosion of the granite coast of Val de Saire. The work, designed by engineer Paul Minard, is composed of a rock rock rock rock from the Becquet quarries, covered with prefabricated blocks and a granite superstructure from Fermanville and the Dielette.

The dam incorporates a 50-metre pass, named Cabart-Danneville in tribute to the Member of Parliament for the English Channel who defended its creation. This opening allows fishermen to move quickly into the harbour in the event of a storm. The project was suggested in 1888 by Admiral Krantz, then Minister of the Navy, during President Sadi Carnot's visit. The works, entrusted to the company Collignon, were part of a series of developments aimed at modernising and securing maritime access to Cherbourg, a strategic port since the 18th century.

The borough of Cherbourg, the construction of which began in 1783 under Louis XVI, was a pharaonic site spread over more than a century. The central dike, completed in 1853, and the eastern and western dikes, completed in 1895, form a set of more than 6 km. The Collignon dam, although more recent, is part of this defensive and logistical system designed to house a military and commercial fleet. Its arc-of-circle profile, linking the Pointe des Grèves to Pelee Island, illustrates 19th-century maritime engineering, combining functionality and resistance to the assaults of the sea.

The harbour played a key role in French naval history, hosting major events such as Queen Victoria's visit in 1858 or the Titanic stopover in 1912. The Collignon dyke, although less mediated than the Large dyke, is involved in the protection of a harbour complex that resisted the conflicts, including during the Second World War, where the Germans spared its infrastructures. Today, it remains a testament to the constant adaptation of marine works to strategic and economic issues.

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