Le Redoutable class, SSBN, French Navy first nuclear submarine
Ballistic Missile Submarines, SSBNs, are designated in French SNLE-`Sous-Marins Nucléaires Lanceurs d`Engins`.
In the early 1960s France embarked on the development of a Force De Dissuasion which was initially to be based on a force of five SSBNs. The program not only served to reinforce the incipient political separation between France and the US but also marked the birth of an independent technology which would see the development of both nuclear reactor and ballistic missiles of French design and manufacture.
The first nuclear reactor, the PAT 1, was produced and tested extensively ashore. Development of the missile took place simultaneously, the first French launch of a SLBM-Sub Launch Ballistic Missile, was made of the experimental submarine Gymnote in 1968.
The overall design was closely based on that of the US Navy`s Lafayette class, and these boats were the first French postwar submarines to have a single hull. The 16 missile SLBM compartment is located directly abaft the fin. The propulsion system is unusual in that the single PWR reactor dose not drive geared steam turbines, as in other western nuclear submarines of the period, but drives two turbo-alternators, which in turn provide the power for a single large electric motor. The sixth boat of the class, L`Inflexible, is of an improved type and is officially regarded as a separate class. Her missiles compartment is of the M-4 SLBM, she has quieter machinery and advanced electronics, her torpedo tubes are of the 21"/533mm design, differs from the previous 21.7"/550mm and she can be distinguished externally from her sisters by her re-shaped fin, with the hydroplanes mounted high on the forward edge.
Specifications, Le Redoutable class, Le Redoutable S-609:
Displacement (srf/sub tons): 8,080/8,920
Dimensions (L*B*D feet): 422`1*34`8*32`8
Propulsion: 1*GEC Alsthom K-15 Pressurized Water Reactor (PWR), drives two turbo-alternators, which in turn provide the power for a single large Jeumont-Schneider 16,000hp electric motor, one screw
Speed (sub knots): 25
Range (srf/sub miles@knots): not relevant
Diving depth (feet): 985
Complement: 15 officers 115 enlisted
Missile: 16*SLBM (Submarine Launch Ballistic Missile) located aft of the fin structure capable of launching Aerospatiale M4/TN 71 (2,860 n/miles up to 6 thermonuclear warheads), SSM (submarine launched anti-ship missiles) Aerospatiale SM 39 Exocet launched from the torpedo tubes.
Torpedo: 4*21" (533 mm) bow torpedo tubes, atotal mix of 18 torpedoes or Exocet missiles.
A total of five boats were constructed in this class all by Cherbourg Naval Dockyardsand launched between December 1969 and September 1977. L`Inflexible the sixth of class, modified, was constructed later, and launched in June 1982.
These ballistic missile submarines were previously known as the Le Redoubtable class (and are sometimes referred to as the modified Le Redoubtable class). But when the vessel bearing that name was decommissioned in 1991, they were renamed the L`Inflexible class, after the newest vessel.
The other four submarines have undergone a two and a half year modernization overhaul in the 1980s which fitted the M-4 missiles, replaced the missile launch system, installed new reactor cores, updated the sonar, and improved quieting up to the standard of the L`Inflexible.
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