The UK鈥檚 Royal Navy may return to the age of sail, with a new demonstration involving a flotilla of small, wind-propelled robot boats.
Made by Oshen in Plymouth, UK, the vessels, known as C-Stars, are just 1.2 metres long and weigh around 40 kilos. Solar panels power navigation, communications and sensors, while a sail provides propulsion. Deployed as a constellation, the small vessels act as a wide-area sensor network.
鈥淭he simplest way of describing C-Stars is as self-deploying, station-keeping ocean buoys,鈥� says Oshen CEO .
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The boats can sail at about 2 knots, covering around 50 miles per day, or use the wind to remain in place rather than drifting. They don鈥檛 need to be fast. 鈥淪peed is not important when you are a CCTV network,鈥� says Laverack. 鈥淭he idea is to position sensors everywhere you need them.鈥�
In the trial announced this month, a larger robotic vessel will transport three C-Stars and drop them off in the target area. The C-Stars will then relay acoustic signals from an uncrewed submarine. Many more would be deployed in a live operation.
鈥淚f you only have one, then the adversary can tell the general area of the submarine it is communicating with. If you have a hundred, the submarine could be anywhere, under any of them,鈥� says Laverick.
The uncrewed boats can stay at sea for six months or more and survive the worst sea states. Last year, C-Stars became the first uncrewed vessels to , as part of a research project involving the US National Oceanic and Atmospheric Administration.
If the navy demonstration is successful, robot sailboats could take on a variety of roles. In addition to communication with submarines and seabed sensors, they could form picket lines to detect ships, incoming missiles, or drones trying to sneak under radar.
C-Stars also seem ideal for submarine detection as an alternative to disposable sonar-equipped buoys, which only last a few hours. They can use their hydrophones to listen for subs or pick up reflected sonar pings from an external source such as a warship. In this scenario, the ship鈥檚 sonar effectively lights up an area, so that the C-Stars can see anything near them.
at the University of Southampton, UK, says solar- and wind-powered uncrewed vessels have gradually become accepted over the last decade, and around 100 of various types are in service. He says autonomy will be essential with a fleet of them.
鈥淚t isn鈥檛 only the platform costs, but it is how much oversight they need for their operations,鈥� says Thornton. 鈥淭he combination of long endurance, robust operations with minimal need for human interaction can be a major advantage and allow large fleets of autonomous systems to operate.鈥�
The latest demonstration aims to show C-Stars can easily integrate with existing navy systems. Oshen could deliver 1000 boats with a nine-month lead time if the navy decides to place an order.
鈥淭he next level will involve software refinements so we can see more detail and achieve better coverage of a wider area with fewer C-Stars,鈥� says Laverack.
Article amended on 12 February 2026
We amended details of the communication between the C-stars and the submarine in the trial.
