France has launched the first sea trials of its fourth Barracuda-class nuclear-powered attack submarine, De Grasse, marking another milestone in the country’s ambitious modernization of its underwater fleet.
The “Alpha Trials” began off the Normandy coast near Cherbourg, where engineers and sailors are testing propulsion, navigation, and combat systems at sea for the first time. The program is managed by Naval Group, the state-backed shipbuilder responsible for constructing the new generation of submarines.
De Grasse follows three earlier vessels already in service with the French Navy, steadily replacing the aging Rubis-class boats that have operated for decades. Officials say the new submarines offer greater stealth, firepower, and endurance tailored to modern naval warfare.
The submarine is named after François Joseph Paul de Grasse, the celebrated French naval commander whose victory over the Royal Navy at the Battle of the Chesapeake in 1781 helped secure American independence. The name reflects France’s tradition of honoring historic maritime figures with frontline vessels.
According to naval commanders, De Grasse introduces several technical improvements over the first three boats in the class. In a recent interview, Xavier Petit, head of France’s submarine forces, highlighted upgrades to the combat management system and a new generation electronic warfare suite designed to improve situational awareness and survivability.
Dockside testing has been ongoing since the submarine’s launch. Engineers completed extensive checks inside assembly halls and flooded docks, verifying onboard systems before allowing the boat to venture into open water. The commissioning of its nuclear reactor marked one of the final steps before sea operations.
The Barracuda-class — also known as the Suffren-class — forms the backbone of France’s future undersea strategy. The first vessel, Suffren, entered active duty in 2022, followed by Duguay-Trouin and Tourville. Two more submarines, Rubis and Casabianca, remain under construction and are scheduled for delivery before the decade ends.
At nearly 100 meters long and displacing more than 5,000 tons underwater, the submarines are among Europe’s most capable attack boats. They can exceed 25 knots submerged and remain at sea for around 70 days, limited largely by food supplies rather than fuel thanks to their nuclear propulsion.
Their weapons package includes long-range naval cruise missiles supplied by MBDA, heavyweight F21 torpedoes, and modernized anti-ship missiles. These systems allow the submarines to strike targets deep inland, engage hostile ships, and conduct anti-submarine warfare with precision.
Advanced sensors and intelligence-gathering tools further enhance their reach. Non-penetrating optronic masts developed by Safran provide high-resolution imagery directly to the combat information center, eliminating the need for traditional periscopes and reducing exposure while surfaced.
The class also supports special operations missions. A removable dry deck shelter allows discreet deployment of commandos, swimmer delivery vehicles, and underwater drones, broadening France’s capacity for covert reconnaissance and rapid-response tasks.
Defense analysts view the De Grasse trials as a significant step in maintaining France’s status as one of the few nations operating advanced nuclear-powered attack submarines. As maritime tensions rise globally, underwater platforms are increasingly seen as critical tools for deterrence and intelligence.
If testing proceeds as planned, De Grasse will join the fleet within the next two years, strengthening France’s ability to project power below the surface while remaining largely undetected — a defining advantage in modern naval combat.