The deployment of flying drones during the Ukraine conflict has drastically transformed ground combat strategies. A similar evolution appears to be underway beneath the waves.

Global navies are in a race to incorporate autonomous submarines. The Royal Navy is set to introduce a fleet of unmanned underwater vehicles (UUVs) aimed at tracking submarines and safeguarding undersea cables and pipelines for the first time. Australia has committed $1.7 billion (£1.3 billion) to develop a ‘Ghost Shark’ submarine to combat the growing presence of Chinese submarines. Concurrently, the expansive US Navy is investing billions in multiple UUV initiatives, including one already operational that can be deployed from nuclear submarines.

Scott Jamieson, managing director of sea and land defense solutions at BAE Systems—the UK’s foremost arms manufacturer and nuclear submarine builder—asserted that autonomous unmanned submarines signify “a significant shift in the underwater combat domain.” New unmanned vessels under development will enable the Navy to “scale operations in ways not previously possible” at “a fraction of the cost of manned submarines,” he noted.

Established defense giants like BAE Systems, General Dynamics, and Boeing are competing with innovative startups such as Anduril, creator of the Ghost Shark, and Germany’s Hellsing for lucrative new market possibilities. Startups argue that they can deliver solutions more rapidly and cost-effectively.

The contest for underwater dominance has persisted almost continuously for the last century, both during peacetime and in conflict.

The first nuclear-powered submarine, the American Nautilus—named after Jules Verne’s fictional vessel—was launched in 1954. Today, nuclear-powered vessels constitute the backbone of the military forces of six nations: the United States, Russia, Britain, France, China, and India, with North Korea potentially joining this group recently. This occurs amidst ongoing debates about the value of such costly weapons and their effectiveness as deterrents.

Naval forces engage in a constant game of hide and seek beneath the waves. Submarines seldom surface to evade detection. Recently, due to maintenance issues with other vessels, some British submarines spent an unprecedented nine months submerged, carrying Trident nuclear missiles that could be deployed at a moment’s notice.

Monitoring Russia’s underwater nuclear capabilities, which have been largely inactive in recent years, is crucial for the Royal Navy, especially around the Greenland-Iceland-UK (GIUK) Gap, a critical juncture for NATO allies to observe Russian activities in the North Atlantic. An executive from an arms company mentioned that the South China Sea represents another promising opportunity as China and its neighbors confront each other in a protracted territorial standoff.

Underwater drones have the potential to enhance the tracking of competing submarines. Some sensors are designed to be deployed by other unmanned probes and can remain underwater for extended periods, as per the aspirations of executives looking to market them to Britain.

A growing concern is the increase in attacks on oil and gas pipelines, exemplified by the 2022 Nord Stream incident, where a Ukrainian suspect was identified, and the 2023 attack on the Baltic Connector pipeline linking Finland and Estonia. Undersea power and internet cables are vital for the global economy, as evidenced by the disruption caused to an undersea power cable between Finland and Estonia last Christmas—just two months following the severing of two communication cables in the Baltic Sea.

Recently, the British government accused the Russian surveillance vessel Yantar of intruding into UK waters to map undersea cables, noting a 30% rise in Russian vessels threatening British waters over the past two years.

Parliament’s Defense Select Committee has raised alarms about the UK’s susceptibility to undersea sabotage—so-called “grey zone” actions—which can lead to significant disruptions without escalating to outright war. The committee warned that damage to any of the 60 undersea data and energy cables around the British Isles could “have a devastating effect on the UK.”

Andy Tomis, CEO of Cohort, a British military technology firm renowned for developing sonar sensors, highlighted that traditional manned ships, aircraft, and submarines used to track nuclear-powered submarines and potential sabotage vessels are “highly sophisticated and costly.” However, he added, “by integrating unmanned vessels with these systems, we can achieve human-like decision-making capabilities without endangering lives.”

Cohort hopes to implement some of its towed sensors (named Crait after a sea snake) on smaller autonomous vessels.

Modern naval ships are equipped with five times more sonar sensors than active submarines. Reduced power needs are crucial for small unmanned vessels, which cannot accommodate nuclear reactors. Passive sensors that do not emit sonar “pings” complicate detection and destruction.

The Royal Navy, along with the British Army, has historically lagged in rapidly adopting the latest technologies. However, lessons from the Ukrainian military underscore the importance of swiftness and cost-effectiveness in drone production for aerial and maritime applications. In response, the Defense Ministry is advocating for the swift development of a technology demonstrator under Project Cabot.

BAE has already conducted tests using a candidate dubbed Herne. Hellsing is establishing a facility to manufacture underwater drones in Portsmouth, the Royal Navy’s home base. Anduril, led by Donald Trump fundraiser Palmer Lackey, is planning to set up a manufacturing site in the UK.

Initial contracts are expected to be awarded this year, with tests likely to take place in north-west Scotland conducted by defense company QinetiQ. A full-scale order for one or two companies, including Atlantic Net, is anticipated to address sensor needs in the GIUK area.

Sources indicate that the Royal Navy has termed the initiative “anti-submarine warfare as a service,” a play on the phrase “software as a service.” A £24 million tender announcement was published in May.

Sidharth Kaushal, a senior fellow specializing in seapower at the Royal United Services Institute think tank, emphasized that the submarine-hunting strategies employed in recent decades “are not scalable in conflict” due to their reliance on costly and highly specialized assets.

The warship will tow a cable extending over 100 meters, equipped with an array of sonar sensors designed to detect the faintest sounds and lowest frequency vibrations. Aircraft from Britain’s fleet, like the Boeing P-8s, deploy disposable sonobuoys to locate deep-sea submarines. Simultaneously, satellites monitor the surface for wake trails left by submarine communication antennas and observe for patrols of hunter-killer submarines lurking below.

The proposal that inexpensive drones could handle much of this task is intriguing. However, Kaushal cautioned that the cost benefits “remain to be verified.” Industry leaders have indicated that large UUV fleets will still incur significant maintenance costs.

Safeguarding submarine cables presents a dual challenge, as sabotage may become more accessible and less expensive. One executive remarked that the likelihood of drones engaging each other underwater is “entirely plausible.”

The Ministry of Defense describes this initiative as “contractor-owned, contractor-operated, and naval-surveilled,” marking the first instance in which a civilian-owned vessel might partake in anti-submarine missions, thus raising the potential of becoming a military target.

“Russia’s immediate response will likely be to test and gauge this capability,” commented Ian McFarlane, head of underwater systems sales at Thales UK. Thales currently supplies the Royal Navy with sonar arrays for submarine detection, unmanned surface craft, and aerial drones, aiming to contribute to Project Cabot by integrating relevant data.

However, Mr. McFarlane insisted that involving private firms is crucial as the Royal Navy and its allies require “mass and resilience now” to address the threats posed by “increasing aggressors.”