French submarine Redoutable (S611)

Le Redoutable (S 611) was the lead boat of her class of ballistic missile submarines in the French Marine nationale.

Commissioned on 1 December 1971, the boat was the first French SNLE (Sous-marin Nucléaire Lanceur d'Engins, "Device-Launching Nuclear Submarine"). The boat was initially fitted with 16 M1 MSBS (Mer-Sol Balistique Stratégique) submarine-launched ballistic missiles, delivering 450 kilotons at 2000 km. In 1974, the boat was refitted with the M2 missile, and later with the M20, each delivering a one-megatonne warhead at a range over 3000 km. Le Redoutable ("formidable" or "fearsome" in French) was the only ship of the class not to be refitted with the M4 missile.

Le Redoutable had a 20-year duty history, with 51 patrols of 70 days each, totalling an estimated 90,000 hours of diving and 1.27 e6km of distance, the equivalent of travelling 32 times around the Earth.

The boat was decommissioned in 1991. In 2000, the boat was removed from the water and placed in a purpose-built 136 m dry dock, and over two years was made into an exhibit. This was a monumental task, the biggest portion of which was removing the nuclear reactor and replacing the midsection with an empty steel tube. In 2002, the boat opened as a museum ship at the Cité de la Mer naval museum in Cherbourg-Octeville, France, being now the largest submarine open to the public and the only nearly-complete ballistic missile submarine hull open to the public — although several museums display small portions, such as sails and/or parts of rudders from such submarines. Special dinner events for organizations aboard this boat's interior spaces are offered by Cité de la Mer.