The Royal Navy wants a Danish frigate to be able to relieve a British warship in the Atlantic and take control of its uncrewed vessels and sensors. That ambition puts sonar and the systems connecting it to allied fleets at the heart of Britain’s underwater surveillance plans.

Recent REPMUS trials in Portugal tested elements of this approach, including autonomous boats towing sonar and underwater gliders carrying acoustic arrays.

The challenge is how allied navies sustain that surveillance for months on end without losing track of submarine activity. This will shape procurement priorities, with sonar performance, compatibility across platforms and long-term support central to turning successful trials into operational capability.

Visiongain Top Takeaways

• Britain sets out its Atlantic defence plans: The Hybrid Navy will combine conventional warships and autonomous systems, but questions remain over the geographical reach of Atlantic Bastion.
• NATO tests autonomous anti-submarine warfare: REPMUS 2026 trialled sonar-equipped vessels and underwater gliders, although sustained operational performance remains unproven.
• Shipbuilding decisions could affect delivery: The proposed Common Combat Vessel remains at an early design stage, highlighting the challenge of coordinating delivery with autonomous platforms and supporting systems.

A New Approach to Atlantic Defence

“A ship operating alone is now vulnerable,” warned First Sea Lord General Sir Gwyn Jenkins in his 16 September Battle for the Atlantic speech. His proposed Hybrid Navy would combine conventional warships with uncrewed escorts and autonomous sensors.

Central to the strategy is Atlantic Bastion, intended to protect Britain’s nuclear deterrent and critical undersea infrastructure. Jenkins also called for closer cooperation among Northern European navies, including a common British-Norwegian frigate force.

He revealed that the Royal Navy was deploying an average of two warships a week to monitor Russian vessels and the shadow fleet, illustrating the demands already placed on Britain’s surface fleet.

The strategy itself faces scrutiny. RUSI has questioned whether a surveillance barrier concentrated in the Norwegian Sea would sufficiently constrain Russian submarines. Its analysis argues for extending coverage westwards into the Atlantic and eastwards towards the Barents Sea, alongside credible options for responding to detected threats.

REPMUS Puts Atlantic Bastion to the Test

The Royal Navy’s REPMUS 2026 trials in Portugal tested emerging technologies intended for Atlantic Bastion.

Underwater gliders carrying acoustic arrays were deployed alongside uncrewed surface vessels providing real-time submarine contact reports. Two autonomous boats, measuring 12 and 17 metres, also tested towed sonar, sonobuoy deployment and the launch of underwater gliders.

The Royal Navy described the use of groups of uncrewed surface vessels as a proof of concept for larger formations. Several technologies remain under evaluation rather than in operational service.

The trials showed how acoustic sensing could be distributed across multiple platforms. They did not establish whether such networks could sustain submarine tracking over extended periods, particularly as changing acoustic conditions, limited underwater communications and platform endurance constrain performance.

Procurement Faces Its Own Test

Jenkins has called for the Royal Navy to “move at the speed of the threat”. Yet the proposed Common Combat Vessel, intended to take over roles currently performed by the Navy’s six Type 45 destroyers and control uncrewed systems, remains at an early design stage.

Using an existing frigate design, such as Babcock’s Type 31, could accelerate development. However, the Type 31 programme has faced costly rework, including a further £140 million charge recognised by Babcock in its 2026 results.

The government has earmarked at least £1.3 billion for the wider Hybrid Navy, including autonomous platforms and future command vessels. Specific service-entry dates have yet to be set for the Type 92 uncrewed underwater sensing platform or Type 93 extra-large underwater vehicle.

Britain faces a difficult scheduling problem: bringing its command ships, autonomous vessels and supporting systems into service together, rather than years apart.

Market Outlook

Visiongain forecasts the global Sonar Systems Market to grow from US$4.59 billion in 2027 to US$9.84 billion by 2037, a 7.9% CAGR.

Deployable sonar systems are projected to reach US$8.38 billion by 2037, reflecting demand across anti-submarine warfare, underwater surveillance and other applications.

The shift towards distributed surveillance could influence which sonar technologies navies select. Suppliers able to demonstrate reliable performance across different platforms, compatibility with naval combat systems and dependable long-term support will be well placed to compete.

Visiongain Insight

Atlantic Bastion could change how Britain deploys its naval forces. Persistent autonomous sensing may allow frigates and maritime patrol aircraft to spend less time searching and more time investigating and responding to submarine contacts.

That could extend coverage without a corresponding increase in crewed ships and aircraft. But autonomous systems still need operators, maintenance and support infrastructure.

Naval planners must weigh whether these networks will free up scarce warships for other missions or add to the pressures on an already stretched fleet.

From Visiongain

Visiongain’s new Sonar Systems Market Report 2027–2037 examines the market forecasts, technologies and competitive developments shaping the sonar market.

View report and request sample pages.

Explore our wider Undersea Defence Intelligence Programme.

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