A new German underwater drone is pushing one of the ocean’s hardest jobs into a different era. The Greyshark Foxtrot, built by Bremen-based Euroatlas with Berlin partner EvoLogics, is an uncrewed autonomous underwater vehicle (AUV) that uses a hydrogen fuel cell and is designed to stay submerged for up to 16 weeks.
That matters because the sea floor is no longer just a quiet place for fish, shipwrecks, and mud. It is also where internet cables, energy lines, pipelines, and military sensors sit out of sight, carrying the data and power that keep everyday life moving.
Euroatlas says the Greyshark system is meant to watch that hidden network for damage, mines, submarines, and suspicious objects without keeping crews at sea for weeks at a time.
Greyshark begins sea tests
Greyshark Foxtrot began its first in-water testing during the week of April 6, 2026, off Damp near Kiel on Germany’s Baltic coast. Testing then continued the following week with the Seabed Security Experimentation Centre near Rostock, according to Janes, which reported comments from Verineia Codrean, Euroatlas’ head of strategy and partnerships.
The vehicle is still in a testing phase, so this is not a finished mass-market ocean robot. Janes noted that the Foxtrot was at technology readiness level four when the water tests began, meaning its propulsion and systems had previously been tested on land. That is an important detail. Big claims under water need proof, not just a glossy brochure.
Why cables need guards
Submarine cables are easy to forget because we never see them, but they carry the backbone of modern communications. The International Telecommunication Union says submarine cables carry approximately 99 percent of the world’s internet traffic, supporting cloud services, government communications, financial transactions, and the everyday messages people send without thinking twice.
Recent cable damage in the Baltic and North Sea has made that vulnerability harder to ignore. Reuters reported that European states have been buying autonomous underwater drones for military use as countries respond to perceived threats, including risks to undersea cables, submarine tracking, and mine detection.
A cut cable is not just a technical headache. It can mean slower networks, higher repair costs, and nervous governments.
Hydrogen gives it range
The Foxtrot’s biggest selling point is endurance. Euroatlas’ official technical overview says Greyshark can operate for up to 16 weeks and travel about 1,100 nautical miles at 10 knots, or about 1,266 regular miles at 11.5 mph. At a slower 4 knots, or about 4.6 mph, the company lists a range of 10,700 nautical miles, which is roughly 12,315 miles.
That endurance comes from the hydrogen fuel cell. In simple terms, a fuel cell uses hydrogen and oxygen to generate electricity through a chemical reaction, producing water and heat as byproducts, according to the U.S. Department of Energy.
The environmental footprint still depends to a large extent on how the hydrogen is produced, but inside the vehicle, the system avoids conventional combustion.
A sea-floor camera with decisions
Greyshark is not just a slow-moving underwater camera. Euroatlas says the AUV carries onboard AI for automatic target recognition, collision avoidance, and dynamic mission adaptation. Effectively, it can begin by inspecting a cable route and then shift its behavior if its sensors detect something that looks like a mine or an unauthorized object.
The sensor package is also central to the idea. Euroatlas materials describe navigation systems, acoustic positioning, electromagnetic sensors, multibeam sonar, laser imaging, synthetic aperture sonar, passive and active acoustic sensors, depth sensors, and temperature sensors.
EDR Magazine, reporting Euroatlas’ announcement, said Greyshark AUVs use an integrated suite of 17 sensors for operations such as cable monitoring, reconnaissance, and minesweeping.
Six drones for Hormuz
One striking example involves the Strait of Hormuz, the narrow waterway between Iran and Oman. The U.S. Energy Information Administration says flows through Hormuz in 2024 and early 2025 made up about one-fifth of global oil and petroleum product consumption. Consequently, any mine threat there can quickly become an energy problem that shows up far from the Gulf, even on the electric bill.
Interesting Engineering reported that Euroatlas says six Greyshark vehicles, operated by one person, could map the entire Strait of Hormuz in no longer than 24 hours. Codrean put the point bluntly, saying, “No manned asset would be able to do it that fast.” That is a company claim, not an independent field result, but it shows why navies are paying attention.
The Bravo and the Foxtrot
Euroatlas has developed two Greyshark versions. Bravo is battery-powered and intended for shorter missions where recovery is easier. Foxtrot is the larger hydrogen-fuel-cell model, built for longer endurance in places where bringing the vehicle back often would be impractical.
The Bravo is about 21 feet long and weighs roughly 7,700 pounds, while the Foxtrot is reported at about 23 to 26 feet and roughly 9,900 pounds. The difference sounds technical, but it changes the mission. A short-range drone checks a known area. A long-endurance drone can sit inside a much bigger story.
A quieter kind of patrol
Underwater surveillance has usually depended on ships, submarines, aircraft, divers, and remotely operated vehicles. That comes with fuel, crew risk, scheduling limits, and noise. Greyshark’s promise is persistence, watching from below while staying hard to spot. Euroatlas says the system is designed for low detection, with a flooded hull, low-metal construction, silent electric propulsion, and a bio-inspired shape.
However, there is another side to this. More autonomous machines in the ocean will also raise questions about accountability, acoustic disturbance, military escalation, and who controls the data collected from sensitive seabed zones. The technology may help protect cables and reduce danger to crews. It also needs rules that keep the ocean from becoming an invisible battlefield.
What comes next
For now, Greyshark Foxtrot is best understood as a serious test of a bigger idea. Can hydrogen power, AI, and acoustic networking give countries a persistent view of the sea floor without sending people into danger every time a cable breaks or a mine is suspected?
The answer is still being written in cold Baltic water. If the promised endurance holds up, Greyshark could become part of a new class of underwater guardians, one that watches the infrastructure most of us depend on but almost never see.
The official technical overview was published on Euroatlas.
