French Navy SSN ‘Suffren’ Performs Static Dive Test as Part of Initial Sea Trials

Led by the French Armament Directorate (DGA), these sea trials will last several months. They will confirm the seaworthiness and efficiency of the submarine before its delivery to the French Navy.

According to our information, these sea trials were set to begin in March but have been slightly postponed because of the COVID-19 epidemic. A DGA spokesperson declined to confirm this information however, explaining (yesterday) that “the Ministry of the Armed Forces does not detail the schedule or the nature of any armament program’s test campaign, in this case we will not comment, to date, on the Suffren’s testing program”.

The Suffren has just completed its first dive at sea. An apparently modest step, but much awaited for a first in class ship. The trials of this formidable hunter are launched, they will last several intense months and we will ultimately deliver a formidable fighter.

Admiral Prazuck, Chief of Staff of the French Navy

As we reported previously, the sea trails will initially take place around Cherbourg (where the first static diving was conducted), then in Brest area (for deep diving tests) and finally in Toulon area (in the late summer/early fall of 2020) for tests of the weapon systems. Commissioning by the French Navy should take place in late 2020.

Watch this video of Suffren SSN starting sea trials:

For the record, Suffren was unveiled during a symbolic launch ceremony on July 12, 2019. It was then ‘launched’ from a platform (which belongs to the DGA) which was lowered inside a dry dock. The dry dock was flooded on August 1st 2019. The next big event was the start of the nuclear boiler which took place in December 2019. The first crew completed its pre-sea trials training in December 2019 as well.

Started in the English Channel, these sea trials will lead the Suffren to the Atlantic and finally to the Mediterranean. Carried out under the supervision of engineers and technicians from the DGA, the French Atomic Energy and Alternative Energies Commission (CEA), Naval Group and TechnicAtome, they will be carried out by submariners of the French Navy to check, gradually, all of the ship’s technical and operational capabilities. They will last several months until a delivery scheduled for later this year. During the entire phase of sea trials, the ship remains the property of Naval Group. Suffren is placed under the responsibility of the French Navy for its operational command and as a delegated nuclear operator. As the contracting authority for the Barracuda program, the DGA is in charge of the test campaign up to the acceptance of the ship and its delivery to the French Navy.

French Ministry of the Armed Forces

The statement issued today added that at dockside, as at sea, the test campaign follows the specific health prevention and precautionary measures linked to the COVID-19 pandemic. In particular, all crew memebers for sea trials have been placed in a preventive 14 days quarantine and have been tested negative for COVID-19. On board, wearing a mask will be mandatory at all times and the rules of hygiene and disinfection will be strictly applied.

About Submarine Static Dive Test

Static dive test usually consists in the controlled intake of water into the submarine’s ballast tanks until it is completely submerged without the use of its propulsion. The procedure is designed to ensure not only the sealing and longitudinal and transverse stability of the submarine while underwater, but also to record the volume of water that is admitted to the internal ballast tanks. These values ​​are then used to accurately determine the submerged displacement of the submarine.

Static immersion are typically the first in a series of sea acceptance tests. Sea trials will culminate with the test-firing of the Suffren‘s weapon systems:

• a F21 heavyweight torpedo
• a SM39 Exocet Block 2 Mod 2 anti-ship missile
• a naval cruise missile

Tests with the dry deck shelter for special forces (commandos marines) swimmer delivery vehicle will likely take place as well, as some point in the test campaign:

About Suffren-class SSN

The Suffren-class is designed to replace the Rubis-class in the French Navy (Marine Nationale). Naval Group is in charge of the construction of this submarines series, including the design and construction of the ship and information systems as well as the manufacturing of the main components of nuclear boiler rooms.

The “launch event” took place on July 12 2019 in presence of French president Emmanuel Macron. The actual “launch in the water” took place on August 1st, when the submarine entered the water for the first time at the Naval Group shipyard in Cherbourg, Normandie.

Suffren-class submarines specifications

• Surface displacement: 4,700 tonnes
• Diving displacement: 5,300 tonnes
• Length: 99 metres
• Diameter: 8.8 metres
• Maximum depth: > 350 meters
• Armament: naval cruise missiles, F21 heavy-weight wire-guided torpedoes, modernized Exocet SM39 anti-ship missiles
• Hybrid propulsion: pressurized water reactor derived from the reactors on board the Triomphant-type SSBN and Charles-de-Gaulle aircraft carrier, two propulsion turbines, two turbo generators and two electric motors
• Crew: 65 crew members + approx. 15 commandos
• Availability: > 270 days per year

To learn more about the Barracuda type, check out our in-depth reporting