Sea Drones: Game Changer on the High Seas

Maritime drone technology is increasingly common on the world's waterways among state and non-state actors alike. We are just starting to see the consequences.

A mockup of the Ukrainian Magura V5 sea drone. Image Source.  

In the early hours of March 5, the Sergey Kotov – a large Russian patrol vessel – navigated the waters of the Kerch Strait, a strategic chokepoint heavily contested between Russia and Ukraine. The estimated $65 million vessel, which was commissioned into Russia’s Black Sea Fleet just two years prior, was a regular target of Ukrainian forces, withstanding two attacks in 2023 alone. Suddenly, the vessel’s crew raised an alarm upon sighting multiple marine drones headed their way. Although crewmembers fired at the drones with heavy machine guns, it was to no avail. An unknown number of Ukrainian Magura V5 sea drones struck the vessel, sinking it and taking the lives of seven crewmembers. 

The Sergey Kotov was the fifth Russian vessel sunk by Ukraine’s Group 13 unit, which falls under its military intelligence agency. The use of sea-based unmanned systems is rising worldwide, with both above-water and underwater vessels increasingly being found in conflicts worldwide. These will likely become both integral and dangerous to maritime security moving forward. 

The Sergey Kotov after being hit by a Maguro V5 drone on March 5. Video Footage. 

The Current Use of Sea Drones

Ukraine provides some of the most prominent examples of state actors using sea drones in open conflict. Kyiv’s navy suffered substantial losses upon Russia’s 2014 annexation of Crimea, forcing it to engage Russia’s vastly superior navy in the current war. Last year, Ukraine established the Group 13 unit to combat Russian attempts to blockade its ports and go on the counteroffensive: the Magura V5 sea drone is its weapon of choice. 

Named after the pre-Christian Slavic goddess of war and victory, the Magura V5 can carry a payload of 200–300 kilograms with a range of 800 kilometers. Because they are mostly plastic, these units are also difficult to detect on radar and thermal cameras. Although the Magura V5 is prone to interception, its $250,000 price tag makes it a cost-effective alternative to anti-ship missiles that cost between $1–2 million and are relatively scarce. The Magura V5 is also highly maneuverable, and because they are controlled by a device not much larger than a standard briefcase, operators can take them almost anywhere. In addition to the Magura V5, Ukraine claims to possess sea drones capable of reaching top speeds of 90 kilometers per hour that can carry up to 850 kilograms of explosives and travel up to 1,000 kilometers. 

Ukraine’s various sea drones. Image Source

China also uses maritime drones, but in a more covert manner than Ukraine, with many models reportedly in its possession not officially acknowledged by Beijing. In December 2020, Indonesian authorities discovered three Chinese unmanned underwater vehicles off the coast of the province of South Sulawesi, some 1,750 kilometers away from waters disputed by both countries. The Chinese reportedly use these drones to gather information that helps submarines navigate these waters undetected. China uses unmanned ships to patrol, support naval assets, and conduct reconnaissance missions. Chinese companies manufacture a wide variety of sea-based drones with anti-ship and anti-submarine capabilities. One of these units is even shaped like a manta ray to evade detection, while another model introduced in 2022 reportedly weighs 300 tonnes, is 60 meters in length, has a range of 4,000 nautical miles, and includes cannons, missiles, and a torpedo launcher. The secretive nature of China’s sea drone programs suggests they are part of its grey-zone tactics, including those employed by its unofficial Maritime Militia. 

The U.S. also has various sea drones under development, including extra-large uncrewed underwater vehicles. The U.S. Navy reportedly plans to deploy ‘hundreds of thousands’ of these units to the Pacific to deter Chinese ambitions there. 

Satellite imagery showing a suspected Chinese sea drone program. Image Source

Non-state actors are also increasingly turning to sea drones. In early January, Houthi militants in the Red Sea detonated an unmanned surface vessel less than two miles from U.S. Navy assets and commercial vehicles there. According to the head of U.S. Navy Operations in the Middle East, this was the first incident of its kind since the start of the Red Sea conflict. In February, U.S. forces destroyed two Houthi sea drones. Before the Red Sea conflict, the Houthis regularly deployed unmanned boats against Saudi-led coalition forces. In one incident, an explosives-laden Houthi sea drone temporarily disrupted operations at Saudi Arabia’s Jeddah Port – the largest port in the country. The Houthi’s drone technology mostly comes from Iran, meaning Tehran also likely possesses advanced maritime drones as it continues to develop its own maritime militia. 

Narco-traffickers and drug cartels are also increasingly deploying sea drones. In 2022, Spanish police arrested several members of a gang building remote-controlled semi-submersible drones capable of carrying up to 200 kilograms of drugs. This raid was the first time Spanish police encountered such a drug-trafficking vehicle. Increasingly militarized drug cartels have also reportedly experimented with torpedo drones and drones that may be attached to the hulls of other vessels.  

Unmanned drug submersibles recovered by Spanish police in 2022. Image Source

Threats posed by maritime drones

Sea drones are increasingly common in a world of highly contested waterways and vulnerable strategic chokepoints. The proliferation of these, especially by non-state actors, could make sea travel much riskier, and the Ukraine example demonstrates their capacity to transform conventional theaters of conflict. In addition to other vessels, sea drones pose a major risk to critical infrastructure such as undersea cables, energy pipelines, ports, and more, giving them the capacity to have a devastating impact on the global economy. 

The proliferation of maritime drones comes amid a significant shift in U.S. naval policy. Instead of patrolling the world’s waterways, U.S. ships increasingly focus on multiple potential theaters of conflict and rely more on large assets such as aircraft carriers rather than smaller patrol vessels. The security gaps produced by this shift have already led to an increase in global maritime piracy, and with sea drone technology now increasingly accessible by non-state actors, we could see these vulnerabilities further exploited moving forward. In this way, maritime drones demonstrate yet another manner in which drone technology is revolutionizing conflicts worldwide.