DgcityA swarm of 116 underwater drones has set a world record for the largest autonomous group of its kind, swimming coordinated formations for about 34 minutes with no human steering the individual vehicles. The demonstration, organised by Northwestern Polytechnical University, was recognised by Guinness World Records.
The test took place in a large indoor pool, where the TH-618 drones carried out a planned sequence of formations and manoeuvres across an area roughly 50 by 20 metres. Each drone is compact, about 60 centimetres long and five kilograms, with a stated operating range of around 29 kilometres and up to eight hours of endurance. What makes the swarm notable is less the hardware than how the vehicles find their way.
Underwater navigation is fundamentally harder than navigation in the air or on the road. Radio signals die within a short distance of the surface, so ordinary wireless control is unavailable, and satellite positioning does not penetrate water at all. Operators of conventional underwater vehicles rely on tethers or expensive acoustic links, both of which become awkward when scores of machines move together.
The record-setting drones instead navigate from smartphone-style cameras mounted at the front, using artificial intelligence to interpret what they see and adjust course in real time. Over the 34-minute swim, relying on visual data alone, the group covered more than 500 metres while holding formation. The vehicles had to track neighbours, avoid collisions and stay inside the pattern without being told what to do each second.
That kind of collective behaviour is the harder half of swarm robotics. A single autonomous underwater drone is already a mature product; making more than a hundred agree on positions, react to each other and keep the pattern when one drifts requires distributed decisions and cheap, consistent sensing. Visual navigation also keeps costs down compared with arrays of sonar and acoustic modems.
The setting does impose limits the researchers acknowledge. A calm, clear pool with a tiled floor is forgiving compared with the open sea, where currents push vehicles off course, sediments cloud the water, light fades with depth and waves disturb the surface. A swarm that keeps its discipline through those conditions would be a more decisive demonstration.
Even so, the underlying platforms point to real applications. Fleets of cheap underwater drones could map the seabed in parallel, inspect pipelines and offshore wind foundations, track pollution plumes, monitor fish farms or sweep harbours. The same logic that made aerial drone swarms useful, doing cheaply in an hour what one craft needs days for, applies under water once navigation is solved.
The record also sits inside a fast-moving field. Several navies now treat uncrewed underwater vehicles as core equipment, and uncrewed craft have been used in combat for the first time in recent years. China has pushed particularly hard on larger uncrewed submarines; the new demonstration shows the small, numerous end of the same spectrum.
Next tests will likely move the swarm toward murkier water, stronger currents and longer missions. Getting a hundred drones to swim in formation was the milestone; getting them to do useful work together in the ocean is the one that matters.
