Amethyste class

   The initial design of the Rubis class had unexpectedly high noise levels. Upgrades were applied to the fifth and sixth hulls, the Amethyste and Perle. Both of these submarines are built to the same design, but stretched about two meters. Other improvements were made to the sonar and electronics. Hull and bow were reshaped to improve silencing.

   Two more boats were planned, but were cancelled. The Rubis and Amethyste classes are the smallest nuclear-powered attack submarines to date. Both of these submarines are based in Taulon, but operate frequently in the Atlantic.

   The Amethyste class has a typical three-deck layout of larger SSNs. These boats were designed primarily as anti-submarine platforms. They carry versions of the F 17 and L5 torpedoes and underwater-launched, encapsulated SM.39 Exocet anti-ship missiles.

   These boats are powered by the French 48-megawatt reactor, driving two turbo-alternators and a main electric motor. Sea endurance is limited only by food supplies, which is estimated by 45 days.

   Between 1989 and 1995 the Rubis class boats underwent the AMETHYSTE modernization programme. It brings them up to the standard of the Amethyste class. A new, larger class of SSN is currently in development, and is expected to enter service some time after 2010.