Denmark's armed forces have deployed four uncrewed robotic sailboats, named "Voyagers," for a three-month operational trial in Danish and NATO waters.
Built by Saildrone, a California-based company, these 10-meter-long vessels are designed for surveillance and can operate autonomously for months at sea, powered by wind and solar energy.
The deployment follows heightened maritime tensions and suspected sabotage in the Baltic and North Seas since Russia's invasion of Ukraine in February 2022.
Two of the Voyagers were launched on Monday from Koge Marina, near Copenhagen, joining two others already on NATO patrol since June 6.
Equipped with advanced sensor suites, including radar, infrared and optical cameras, sonar, and acoustic monitoring, the sailboats enhance maritime surveillance capabilities in the region.
Saildrone founder and CEO Richard Jenkins compared the vessels to a “truck” that carries sensors and uses machine learning and artificial intelligence to give a “full picture of what's above and below the surface" to about 20 to 30 miles (30 to 50 kilometers) in the open ocean.
He said that maritime threats like damage to undersea cables, illegal fishing and the smuggling of people, weapons and drugs are going undetected simply because “no one’s observing it.”
Saildrone, he said, is "going to places ... where we previously didn’t have eyes and ears.”
The Danish Defense Ministry says the trial is aimed at boosting surveillance capacity in under-monitored waters, especially around critical undersea infrastructure such as fiber-optic cables and power lines.
“The security situation in the Baltic is tense,” said Lt. Gen. Kim Jørgensen, the director of Danish National Armaments at the ministry. “They’re going to cruise Danish waters, and then later they’re going to join up with the two that are on (the) NATO exercise. And then they’ll move from area to area within the Danish waters."
The trial comes as NATO confronts a wave of damage to maritime infrastructure — including the 2022 Nord Stream pipeline explosions and the rupture of at least 11 undersea cables since late 2023. The most recent incident, in January, severed a fiber-optic link between Latvia and Sweden’s Gotland island.
The trial also unfolds against a backdrop of trans-Atlantic friction, with US President Donald Trump's administration threatening to seize Greenland, a semiautonomous territory belonging to Denmark, a NATO ally. Trump has said he wouldn't rule out military force to take Greenland.
Jenkins, the founder of Saildrone, noted that his company had already planned to open its operation in Denmark before Trump was reelected. He didn't want to comment on the Greenland matter, insisting the company isn't political.
Some of the maritime disruptions have been blamed on Russia’s so-called shadow fleet — aging oil tankers operating under opaque ownership to avoid sanctions.
One such vessel, the Eagle S, was seized by Finnish police in December for allegedly damaging a power cable between Finland and Estonia with its anchor.
Amid these concerns, NATO is moving to build a layered maritime surveillance system combining uncrewed surface vehicles like the Voyagers with traditional naval ships, satellites and seabed sensors.
“The challenge is that you basically need to be on the water all the time, and it’s humongously expensive," said Peter Viggo Jakobsen of the Royal Danish Defence College. “It’s simply too expensive for us to have a warship trailing every single Russian ship, be it a warship or a civilian freighter of some kind.”
“We’re trying to put together a layered system that will enable us to keep constant monitoring of potential threats, but at a much cheaper level than before,” he added.
