What You Need to Know: The Rubis-class submarine's surprising success against the USS Theodore Roosevelt in a 2015 war game highlighted vulnerabilities in U.S. Navy anti-submarine warfare.

-Despite its smaller size and lighter armament, the French Rubis-class submarine, Saphir, penetrated Carrier Strike Group 12’s defenses and "sank" the carrier, emphasizing potential gaps in carrier protection. The Rubis, compact with sophisticated sonar and stealth capabilities, is a capable underwater force even as it approaches replacement by France’s Barracuda-class submarines.

-This event underscored the inherent vulnerability of carriers, reminding naval forces of the need to adapt in the face of advancing submarine technology.

How a French Submarine "Sank" a U.S. Aircraft Carrier in War Games

The aircraft carrier is essentially a floating city that is capable of projecting air power across the world.

Perhaps no other piece of military technology signifies a country’s power like the aircraft carrier.

Yet it is still a man-made machine — a boat, really, and like all boats, a carrier still inherently vulnerable, as a French submarine made clear during war games last decade.

Rubis-Class and a Big War Game

In 2015, the Saphir, a French Rubis-class submarine, participated in a war game with U.S. Carrier Strike Group 12.

The exercise featured the USS Theodore Roosevelt nuclear-powered aircraft carrier, as well as several Ticonderoga-class cruisers, Arleigh Burke-class destroyers, and one Los Angeles-class stealth submarine.

The war games took place off the coast of Florida and reportedly featured two distinct phases. In the first phase, the Saphir was integrated into the U.S. Navy in order to locate an enemy submarine. In the second phase, it was paired with U.S. Navy aircraft and given the assignment of locating and destroying Theodore Roosevelt.

During the exercise, the Saphir was able to slip past opposing vessels undetected and virtually sink the Theodore Roosevelt, as well as four escort ships from the Carrier Strike Group. 

Obviously, the war game’s results were an embarrassment for the U.S. Navy.

Information about the Saphir’s victory was scrubbed from the internet. The Navy went about evaluating what had happened, and the results suggested a shortcoming in the Navy’s anti-submarine warfare capabilities. 

History of the Rubis-Class Submarine

The Rubis was about 30 years old as a class when the French submarine successfully “sank” the Theodore Roosevelt. Smaller than most NATO counterparts, and lightly armed with just 14 torpedoes and missiles, the Rubis is not the vessel most would expect to fell a mighty U.S. aircraft carrier.

But the Rubis, of which France operates six, did indeed penetrate Carrier Strike Group 12’s defenses and land fatal blows upon the multi-billion-dollar vessel. 

The Rubis is 73.6 meters long (241 feet), with a 7.6-meter beam and a 6.4-meter draught.

The sub displaces 2,400 tons. To propel itself, the Rubis relies on a pressurized water CAS-48 nuclear reactor, one electric motor, and one shaft auxiliary diesel generator.

The sub’s top speed is about 25 knots (29 miles per hour). The Rubis is capable of operating at depths up to and including 980 feet below the surface of the ocean. It has an unlimited distance and can operate for 20-25 years. Typically, the endurance of the crew and vessel is rated at about 45 days. 

For sensors and processing systems, the Rubis uses a DMUC 20 active/passive sonar, ETBF DSUB 62 C towed array passive sonar, a DSUV 22 passive cylindrical array sonar with active transducer, and DRUA 33 radar.

For armament, the Rubis relies on four 533 mm torpedo tubes, which can launch a mixed variety of F17 mod2 torpedoes and Exocet SM39 anti-ship missiles.

The Rubis will be phased out in the near future in favor of the new Barracuda-class stealth submarines. But for now, the Rubis is still relevant. 

About the Author: Harrison Kass 

Harrison Kass is a prolific defense and national security writer with over 1,000 published articles. An attorney, pilot, guitarist, and minor pro hockey player, Harrison joined the US Air Force as a Pilot Trainee but was medically discharged. Harrison holds a BA from Lake Forest College, a JD from the University of Oregon, and an MA from New York University. Harrison listens to Dokken.

The main image is of a Brazilian aircraft carrier being decommissioned. The rest of the photos are of the USS Ronald Reagan.