France to launch fifth Suffren-class nuclear attack submarine Rubis in Normandy for long-range strikes.

On October 16, 2026, Naval Group and the French Directorate General of Armaments (DGA) transferred the Rubis (S639), France's fifth Suffren-class nuclear-powered attack submarine, from its Cherbourg construction hall to the Cachin basin launch facility. The industrial maneuver advances the €9.1 billion Barracuda acquisition program managed by the DGA to replace legacy first-generation attack submarines. The event initiates dockside system integration, propulsion checks, and sea trials before formal delivery and operational commissioning with the French Navy.

On October 16, 2026, France began transferring the Rubis, its fifth Suffren-class nuclear attack submarine, from Naval Group’s construction hall in Cherbourg to the Cachin basin launching platform, ahead of final outfitting, launch preparations, and subsequent trials. (Picture source: Naval Group)

On October 16, 2026, France began transferring its fifth Suffren-class nuclear-powered attack submarine, the Rubis (S639), from Naval Group's Cherbourg construction hall to the launching installation in the Cachin basin, Normandy. The operation was attended by Armed Forces Minister Catherine Vautrin, Director General of Armaments Patrick Pailloux, and senior French Navy commanders Alban Lapointe and Xavier Petit. The transfer precedes the submarine's initial flotation, remaining outfitting work, dockside trials, propulsion testing, and sea trials, which must be completed before the Rubis' acceptance by the French Navy. Built by Naval Group with a nuclear propulsion plant supplied by TechnicAtome, the submarine belongs to the six-boat Barracuda program managed by the French Directorate General of Armaments (DGA).

The new SSN class replaces the Rubis-class nuclear attack submarines introduced in 1983, nearly doubling submerged displacement from 2,670 to 5,300 tonnes while maintaining France's planned inventory of six nuclear-powered attack submarines. The new Rubis inherits its name from the Saphir-class minelaying submarine Rubis (Q145), laid down at Toulon on April 3, 1929, launched on September 30, 1931, and commissioned on April 4, 1933. Measuring 65.9 m long, 7.1 m wide, and displacing 940 tonnes submerged, it carried 42 sailors, three 550 mm torpedo tubes, two 400 mm tubes, a 75 mm deck gun, machine guns, and 32 Sautter-Harlé HS4 mines, each containing 220 kg of explosives. Two diesel engines produced 1,300 hp, while electric motors provided another 1,100 hp, allowing the Q145 to reach 12 knots (22 km/h) surfaced and 9 knots (17 km/h) submerged, for an operating depth of 80 m.

Related topic: French Navy begins sea trials of De Grasse nuclear attack submarine before delivery in 2026

The mines were carried in sixteen external vertical shafts, two per shaft, and released underwater using compressed air, allowing the submarine to establish minefields without surfacing. The Rubis joined the Free French Naval Forces at Dundee in June 1940 and conducted operations off Norway and in the Bay of Biscay. The Rubis sank 22 ships during World War II, including 11 German warships, the German submarine U-702 on March 31, 1942, and damaged at least two additional vessels, while its wartime record included 683 mines laid across 28 combat missions. Awarded the Cross of Liberation and War Cross 1939-1945, it was withdrawn in October 1949, was deliberately sunk off the French Mediterranean coast on January 31, 1958, and its name has subsequently been retained within France's nuclear submarine force. 

Four Suffren-class submarines have been delivered since 2020, but only three had entered active service by October 2026. The Suffren (S635) was delivered on November 6, 2020, and entered active service in 2022, followed by the Duguay-Trouin (S636) in 2024 and the Tourville (S637) in 2025. The De Grasse (S638) was delivered in June 2026 but was still awaiting operational admission, while the Rubis (S639) was approaching launch and the Casabianca (S640) remained under construction and is scheduled for delivery by 2030 to complete a submarine acquisition program initiated in October 1998. The Rubis must now complete internal equipment installation, conduct initial flotation, check electrical and propulsion systems alongside the dock, and undertake sea trials to validate navigation, diving, acoustic performance, and weapon-related systems.

The first submarine required nearly two years between delivery and active service, as the French Navy must complete crew training, operational evaluations, and certification before incorporating a new submarine into routine deployments. Each Suffren-class submarine measures 99.5 m long and 8.8 m wide, has a draft of 7.3 m, and displaces 4,650 tonnes surfaced and 5,300 tonnes submerged. Compared with the preceding Rubis-class, measuring 73.6 m long and 6.4 m in hull diameter, the new class is 35.2% longer, 37.5% wider, and 98.5% heavier underwater, providing additional space for weapons, sensors, machinery isolation, and special operations equipment. Its K15 pressurized-water nuclear reactor generates 150 MW of thermal power, which is supplied to a propulsion machinery incorporating two 10 MW turbo-alternators, mechanical and electrical drive arrangements, and a shrouded pump-jet propulsor instead of a conventional propeller.

The submarine exceeds 25 knots (46 km/h) submerged, reaches 14 knots (26 km/h) surfaced, operates at depths exceeding 350 m, and increases endurance from 45 days aboard Rubis-class submarines to 75 days. The submarine accommodates 60 to 65 sailors plus ten combat swimmers, possesses emergency MAN diesel generators, and pushes back nuclear fuel maintenance intervals from seven to ten years. Four 533 mm torpedo tubes provide access to a nominal weapons capacity of 24, including 20 internal storage positions, compared with 14 weapons aboard the Rubis-class. Armament includes F21 Artemis heavyweight torpedoes with a 50 km engagement range, SM39 Exocet Mod 2 anti-ship missiles with a 50 km range, and Naval Cruise Missiles (MdCN) capable of striking fixed land targets beyond 1,000 km. The Suffren-class can therefore attack inland installations while remaining submerged offshore, a mission unavailable to the preceding Rubis-class.

FG29 naval mines can also be carried, with two mines occupying one storage position. An eight-missile MdCN load would theoretically leave sixteen positions for torpedoes and other weapons, including those already loaded in the tubes. This 71.4% increase in ammunition capacity permits the magazine to be adjusted for mining, anti-submarine warfare, surface attacks, or land strikes. The lead submarine also completed qualification firings of F21 torpedoes, SM39 Exocet missiles, and MdCN cruise missiles, validating the class's three principal categories of offensive weapons. Underwater surveillance relies on Thales' UMS-3000 acoustic suite, which combines a bow-mounted sonar, two flank arrays, and a DSUV 62C very-low-frequency towed array for passive submarine detection. The SeaClear obstacle- and mine-avoidance sonar, the Velox-M8 interception equipment, and the NUSS-2F Mk2 navigation echo sounder supplement these sensors.

For its part, the Sycobs combat management system integrates acoustic tracks, navigation, and weapon control within an onboard architecture comprising 200 software applications and 21 million lines of code. Communications include Thales' Partner, a Divesat mast for Syracuse satellite connectivity, X-Sub expendable buoys, as well as compatibility with Link 11, Link 16, and Link 22 tactical data links. Two nonpenetrating optronic masts provide surface observation, while the Nemesis torpedo-defense system and Canto-S acoustic decoys are intended to interfere with incoming torpedo guidance. For special operations, the submarine can carry a removable dry deck shelter that accommodates underwater swimmer delivery vehicles; in March 2026, a Suffren-class submarine also demonstrated the deployment and recovery of a U.S.-built Razorback underwater drone off Toulon. 

Initiated in October 1998, the Barracuda program entered design development in 2002 and construction in 2007, with the lead submarine delivered thirteen years later. The six-submarine acquisition costs €9.1 billion, including an indicative recurring construction cost of €1 billion per Suffren submarine, excluding development, infrastructure, and other nonrecurring expenditure. Each submarine contains 700,000 components, 70,000 assemblies, 500 systems and subsystems, 150 km of electrical cables, and 20 km of piping. The construction of the lead submarine required an estimated 50 million working hours within the principal industrial organizations and another 20 million among subcontractors. More than 10,000 personnel and 800 companies have participated across France, with 3,000 direct jobs mobilized daily, including 800 in subcontracting.

Naval Group handles the hull construction, TechnicAtome supplies the reactor and associated nuclear propulsion equipment, the French Atomic Energy and Alternative Energies Commission contributes nuclear engineering expertise, and the DGA oversees procurement and acceptance. The replacement of the Rubis-class by the Suffren-class changes the missions France can conduct with an unchanged six-submarine attack fleet. The earlier submarines were primarily equipped for anti-submarine warfare, anti-ship engagements, intelligence collection, and protection of naval forces, while the Suffren-class adds land attacks at ranges exceeding 1,000 km, submerged special forces insertion, and unmanned underwater reconnaissance. Its endurance theoretically permits 55 days on station after twenty days of combined transit, compared with 25 days for the Rubis-class, a 120% increase in potential time within the operational area under those assumptions.

The weapon inventory provides ten additional weapons compared with its predecessor, permitting mixed loads of heavyweight torpedoes, anti-ship missiles, cruise missiles, and mines, although increasing the number of cruise missiles reduces capacity for other ammunition. The combination of flank-mounted sonar arrays, a very-low-frequency towed array, machinery isolation, and pump-jet propulsion improves the conditions for passive tracking and covert surveillance, particularly when protecting French ballistic missile submarines. Finally, the ability to embark ten combat swimmers and operate a removable dry deck shelter permits covert insertion and recovery of special operations personnel, while underwater drones can now extend reconnaissance beyond the submarine's immediate position.

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Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, South Korea, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.