The Louis Joubert Lock (French: Forme Ecluse Louis Joubert) also known as the Normandie Dock, is a lock and major dry dock located in the port of Saint-Nazaire in Loire-Atlantique, northwestern France.Owned by the Port authority of Nantes-Saint-Nazaire and not by the ship building company Chantiers de l'Atlantique, its strategic importance as a major naval construction and maintenance asset since its completion in 1934 resulted in it becoming the main target of the British Army Commando raid of 1942, the St.