The French Navy (Marine Nationale) is building seabed warfare capability to secure critical undersea infrastructure (CUI) and to enable its naval operations around the world. Moreover, the navy is taking several steps to build this capability, the senior French naval officer responsible for delivering the program told Naval News.
“When we talk about seabed warfare, always consider that from a French perspective there are two main goals, The first is to protect CUI […] The second is to be able to ensure our freedom of maneuver for naval forces […]
Both aspects are very important for us.“
Rear Admiral Cedric Chetaille, French Navy’s deputy chief for operations
The first goal focuses on generating maritime surveillance to secure CUI like seabed pipelines and cables. The second aims to explore and monitor areas of interest – regions where France intends to operate naval forces – to ensure no threats from sensors or explosive ordnance are present, to enable the Marine Nationale to deploy its own sensors or ordnance to support operational maneuvers, or to recover objects of interest from the seabed, the admiral continued.
Seabed warfare remains a high-priority, high-profile operational task for navies. Following the NordStream gas pipeline explosions in September 2022 and the BalticConnector gas pipeline and internet cable ruptures in October 2023 (with both incidents occurring in the Baltic Sea), in February 2024 reports emerged that several seabed cables in the Red Sea had been attacked, with the Yemen-based Ansar Allah (Houthi) rebel group suspected of being responsible.
With wider availability of new technology – including remotely operated or autonomous underwater vehicles (ROVs, AUVs), artificial intelligence, micro-electronics, and improved batteries – state and non-state actors could develop the capability to conduct seabed operations, said Rear Adm Chetaille. While conducting seabed operations is only an expansion of the existing maritime battlespace, what is new is the fact that a different range of actors can operate there, he added.
To tackle the seabed warfare challenge, the French Navy and France’s armed forces broadly must take three steps, the admiral explained.
“The first is to improve our knowledge of this environment, and our understanding of who is doing what for which reasons, what kind of threats there could be, and what kind of activities,” he said, adding that such understanding would “provide a little bit more transparency of the deep sea, which is still the realm of opacity.”
Surveillance is integral to such transparency. “[The] challenge is to be able to detect, track, and attribute. Once we can do that, we will be able to deter and respond,” said Rear Adm Chetaille.
“Second is to be able to implement general global surveillance in the areas of interest … where we want to deploy our naval forces.” The admiral explained that such areas are much larger than national territorial waters or exclusive economic zones. “Such surveillance must be accurate enough and efficient enough to be able to deliver military effects like preventing hybrid actions or deterring other countries from trying to operate and to threaten our interests there,” he added.
“Third, is to be able to act,” said Rear Adm Chetaille.
“We need to operate robotic systems – our choice is ROVs and AUVs – that can go down to 6,000 metres, enabling us to reach and operate on 97 percent of the world’s seabed.”
For seabed operations, the Marine Nationale must also have capacity to deploy at short notice, to deploy and operate covertly, and to operate in non-permissive environments.
The capability to operate down to 6,000 metres is central to French seabed warfare requirements, and is shaped too by the navy’s wider operational needs.
“It’s driven by our analysis of our areas of interest,” said Rear Adm Chetaille. “When you look at the Atlantic Ocean, for instance, if you can reach 6,000-metre depths, you are able to operate almost everywhere.” “This is linked to our ambition – to be able to act in terms of seabed warfare all around the world, where our interests are at stake or where allies or partners could ask for support,” he added.
Reaching this depth is technologically challenging, the admiral explained. “It’s quite difficult in terms of knowhow, in terms of capabilities, in terms of who is able to do that.” Specific host platforms are needed, with requirements including improved stealth and capacity to carry larger, heavier ROVs. Moreover, the AUVs require greater autonomy because of the time needed to reach such depth.
Few commercial or scientific organisations are operating at these depths; moreover, naval operational requirements on the deep seabed are very different, Rear Adm Chetaille added.
France’s seabed warfare strategy, published in 2022, specified a requirement to achieve capacity to operate at 6,000 metres by 2026. To build and demonstrate this capability, the navy has established its ‘Calliope’ operation, the first deployment for which took place in October 2022 in the Bay of Biscay onboard the oceanographic and hydrographic vessel Beautemps-Beaupré.
Five ‘Calliope’ deployments have been conducted to date; the second, third, and fourth took place across 2023; the fifth is currently underway. The sixth is scheduled for the first half of 2024.
“‘Calliope’ is conducted to reach two objectives,” said Rear Adm Chetaille. “First, we are testing different types of assets – AUVs or ROVs, but from different companies with different payloads. What we want to see, to do, to manipulate [on the seabed] can be very different from what industry is doing. So, it’s a way for us to test all that.”
Platforms are tested, too. France is considering using general-purpose naval vessels – including patrol, supply, or research ships – onboard which it can ‘plug and play’ containerized seabed warfare capabilities. This approach supports the requirements to deploy capability covertly and quickly. The Marine Nationale is also considering whether it should develop a bespoke, dedicated seabed warfare platform, as the UK Royal Navy has done with the MROS vessel RFA Proteus.
“Second, we are trying to generate operational results, to deliver some military effect,” the admiral continued. This involves CUI survey and protection, and securing the seabed (including collecting objects) to ensure freedom of maneuver in areas of interest.
For lessons learned from ‘Calliope’ in supporting the three steps the navy needs to take, “These first operations are an essential step to determine how complementary work is carried out by the AUVs and ROVs,” said Rear Adm Chetaille. “They also enable us to determine the main platform characteristics, specific data processing needs, and required personnel skills.”
