OVERVIEW: The S 615 L *Inflexible* [Le Redoutable Class] is a ballistic missile submarine (SSBN) of the French Navy, representing the final evolution of the class.

DETAILS: The *Le Redoutable* class was conceived in the late 1950s and early 1960s as the cornerstone of France's independent nuclear deterrent force, the *Force de Frappe*. The program was initiated in response to perceived inadequacies in reliance on allied nuclear protection. The *Inflexible*, commissioned in 1986, represents a significant upgrade over the earlier boats, primarily through the incorporation of the M4 ballistic missile system. Design considerations emphasized stealth, reliability, and survivability in the face of potential Soviet anti-submarine warfare (ASW) efforts. The class featured a streamlined hull for reduced hydrodynamic drag, advanced sound dampening measures, and a robust internal layout to withstand shock and vibration. The *Inflexible* was the sixth and final vessel of the class, and served as the cutting edge of France's nuclear deterrence until replaced by the *Triomphant* class.

The primary role of the *Inflexible* was strategic nuclear deterrence, achieved through its capacity to launch nuclear-tipped ballistic missiles from submerged positions. The M4 missile provided a credible retaliatory strike capability. Beyond this strategic mission, the submarine was also capable of limited anti-submarine warfare (ASW) and anti-surface warfare (ASuW) operations, primarily for self-defense. Its acoustic sensors permitted passive detection and tracking of potentially hostile vessels. The 550mm torpedo tubes offered a means of engaging both submarine and surface threats at close ranges. The presence of a signal ejector allowed for communication with shore-based authorities and other naval units without compromising the submarine's submerged position.

The sensor suite aboard *Inflexible* reflects a focus on both strategic deterrence and tactical awareness. The DUUX 5 Fenelon (TSM 2255) sonar provides broad-spectrum active and passive detection capabilities. The DUUV 23 and DSUV 61A arrays likely contribute to improved detection ranges and target classification. The ARUR 10 (DR 2000U) radar intercept receiver is used for detecting and analyzing radar emissions from surface ships and aircraft, improving situational awareness. The DRUA 33C Calypso III (TRS 3100) radar allows for surface navigation and target acquisition when operating at periscope depth. The DUUG 6 (M5) constitutes part of an integrated combat management system, providing fire control solutions for both the M4 missile and the 550mm torpedoes. The submarine's optical and low-light television (LLTV) periscopes provided visual confirmation of targets and navigation data.

SPECIFICATION: Length: 128.0 m || Beam: 10.6 m || Draft: 10.0 m || Disp: 6500 t

SENSORS: DUUX 5 Fenelon [TSM 2255] || DUUV 23 || DSUV 61A || ARUR 10 [DR 2000U] || DRUA 33C Calypso III [TRS 3100] || DUUG 6 [M5] || Generic Submarine Periscope, Optical || Generic Submarine Periscope, LLTV

ARMAMENT: M4/TN70 || 550mm TT || Signal Ejector