Rubis class: the French nuclear submarine that sank a Navy aircraft carrier

Summary and what you need to know: The U.S. Navy’s Nimitz-class aircraft carriers may be formidable, but they are not immune to attack. This was demonstrated during a joint exercise in 2015, in which a French Rubis-class submarine successfully sank the USS Theodore Roosevelt.

-The French Rubis class submarines, known for their compact size and nuclear power, were initially noisy but were later improved with hull modifications. These submarines are equipped with advanced weapons, including Exocet SM39 anti-ship missiles, and have advanced electronic support systems.

-The exercise highlighted how vulnerable even the most advanced aircraft carriers are to stealthy submarine threats.

The compact yet powerful Rubis class: France’s silent fighter

Although the U.S. Navy’s aircraft carriers are among the most formidable ships at sea, they are certainly not immune to attack.

As ‘floating airports’, these types of vessels are an integral part of the modern war space.

Navies began using aircraft carriers to launch heavier aircraft in World War II. In the early stages of the war, the Japanese attacked Pearl Harbor with carrier-based aircraft, demonstrating just how powerful these ships could be.

After this incident, the US prioritized the development and modernization of its own aircraft carrier programs. Today, the Nimitz and Ford class carriers lead the Navy’s operations at sea. Although the Nimitz class ships are considered top-notch by military experts and analysts, they are not immune to all lines of fire.

Rubis class: French submarine sinks US warship during military exercise

In March 2015, the French Ministry of Defense published a report detailing how one of its nuclear-powered submarines (SSN) pretended to sink one of the U.S. Navy’s Nimitz-class ships during a joint exercise in the North Atlantic.

According to the details revealed, the joint military exercises consisted of various imaginary situations that threatened the USS Theodore Roosevelt.

During the first day of the exercise, the French Rubis-class submarine Saphir was integrated into the friendly force, assisting the U.S. Navy’s P-3C Orion and P-8A Poseidon Maritime Patrol Aircraft. On day two, the French ship joined the enemy team, tasked with locating the U.S. aircraft carrier and its warships and preparing for an attack.

Although the details of how the Saphir was able to silently detect and attack Theodore Roosevelt remain a mystery, the French submarine managed to slip through the Nimitz-class carrier’s defenses while evading detection by ASW assets.

Meet the Rubis class

The Saphir is one of the Rubis class nuclear submarines of the French Navy. In the early 1960s, this class was to enter the construction phase, but at the end of the decade, its construction was cancelled.

However, in 1972 a new naval plan was drawn up which provided for the production of 20 attack submarines, both nuclear and conventionally powered.

The project was eventually completed and the second attempt, the Rubis class submarines, entered service with the French Navy.

These vessels were smaller than their foreign counterparts and featured a more compact hull design. The resulting SNA72 class built in Cherbourg is in fact the smallest nuclear-powered submarine in operational service with any navy in the world. The 48-megawatt integrated reactor heat exchanger designed by French engineers has a lifespan of 7 years before needing to be refilled. As detailed by Military Today , the hull depth of these submarines was actually greater than that of its Agosta-class predecessors and allowed for the typical three-deck layout of larger submarines to be used for the areas forward of the fin.

The Rubis class: specifications and possibilities

Although the Rubis-class ships were advanced on paper, the original design of the first submarine in the class proved to be quite noisy.

Since submarines are designed to evade detection by enemy warships, this deficiency was serious. Eventually, the hull was reshaped and lengthened to help reduce noise emissions. The first Rubis submarine entered service in 1983, followed by Saphir in 1984, Casabianca in 1987, Emeraude in 1988, Amethyste in 1992, and Perle in 1993. Two additional submarines, Turquoise and Diamant, were canceled in the early 1990s before they entered their construction phase.

The Rubis class is a powerhouse

In terms of armament, the Rubis-class submarines pack a serious punch. Each ship’s weapons control system is the DLA 2B and DLA 3. As explained by Naval Technology, the torpedo tube-launched Exocet SM39 anti-ship missile can approach a target area in a sea-skimming mode using both active radar homing and inertial navigation.

Each submarine can also carry up to 14 missiles and torpedoes in a mixed load.

The Rubis class ships also use the Thales DR 3000U electronic support system, which complements the other sensors on board, including the Rubis Amethyste’s Type 1007 navigation radar.

About the Author: Maya Carlin

Maya Carlin is an analyst at the Center for Security Policy and a former Anna Sobol Levy Fellow at IDC Herzliya in Israel. She has contributed to many publications, including The National Interest, Jerusalem Post, and Times of Israel. You can follow her on Twitter: @MayaCarlin.

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