test fire missiles and by 1967, the submarine was fitted with the guidance and navigation systems to be tested. The first ballistic missile launch was at the Landes Trials Centre (French: Centre d'Essais des Landes) at the end of 1968 and nuclear warheads were tested at Moruroa in the Pacific Ocean. Description Designated Sous-marin Nucléaire Lanceur d'Engins (SNLE) literally "Missile-launching nuclear submarine", the design initially measured long overall with a beam of and a draught of . The submarines initially displaced surfaced and submerged. This later increased to surfaced. The submarines were powered by one pressurised water reactor providing steam to two turbines and two alternators and turning one propeller via a turbo reduction drive creating . The submarines also sported electric emergency propulsion capable of providing a range of . The vessels could dive more than and had a maximum speed of . Each boat had two twin crews comprising 15 officers and 120 men. Armament The Redoutable class all have 16 compartments for submarine-launched ballistic missiles. Redoutable initially deployed with 16 the M1 MSBS (Mer-Sol Balistique Stratégique). The M1 missile was a two stage ballistic missile with a height and each missile weighed . The M1 had a 400-kiloton warhead and an approximate range. Terrible was also constructed to carry this missile. The design of Foudroyant was altered to carry the improved M2 MSBS missile in 1974. The M2 was heavier at , had a 500-kiloton warhead and a longer range than the M1. In 1977, both the M1 and M2 were replaced by the M20 MSBS. Service history The first submarine, Redoutable, was ordered in 1963, built at Cherbourg, launched in 1967 and commissioned in 1971. This was replaced by the M2 MSBS beginning in 1974, which was in turn replaced by the M20 MSBS beginning in 1977. All except Redoutable were heavily upgraded from 1985 to fire the second generation MIRV capable M4 missile – Tonnant was recommissioned in 1987; Indomptable in 1989; Terrible in 1990; and Foudroyant in 1993. Redoutable has been preserved since 2002 as a museum ship at the Cité de la Mer naval museum in Cherbourg-Octeville, France. The reactor compartment has been replaced by a new section. Vessels in class See also List of submarines of France Citations and references Citations References Submarine classes Cold War submarines of France Ship classes of the French Navy