At first glance, they resemble typical sailboats, their sails marked with Denmark’s red-and-white flag. But these 10-meter (30-foot) vessels carry no crew. Known as “Voyagers,” these robotic sailboats are designed for autonomous surveillance missions and have been deployed by the Danish Armed Forces for a three-month operational trial.
Built by U.S.-based Saildrone, headquartered in Alameda, California, the Voyagers will patrol both Danish and NATO-controlled waters in the Baltic and North Seas. This region has seen a surge in maritime tensions and suspected sabotage following Russia’s full-scale invasion of Ukraine on February 24, 2022.
Two of the four Voyagers began operations on Monday from Koge Marina, about 40 kilometers (25 miles) south of Copenhagen. The other two were deployed earlier, on June 6, to participate in a NATO patrol. Powered by a combination of wind and solar energy, the uncrewed vessels are capable of remaining at sea for months at a time without human intervention.
Each Voyager is equipped with sophisticated sensor technology, including radar, infrared and optical cameras, sonar, and acoustic monitoring systems. These tools allow the vessels to detect activity both above and below the ocean’s surface over a range of 20 to 30 miles (30 to 50 kilometers) in open waters.
What is Strait of Hormuz? Could it play a role in Israel-Iran conflict?
Saildrone’s founder and CEO, Richard Jenkins, likened the Voyager to a mobile sensor platform or “truck” that uses machine learning and artificial intelligence to provide a comprehensive view of maritime activity. He emphasized that critical threats — such as damage to undersea cables, illegal fishing, and smuggling of people, drugs, or weapons — often go unnoticed simply because no one is monitoring these remote regions.
“We’re going to places where we previously didn’t have eyes and ears,” Jenkins said.
According to Denmark’s Defense Ministry, the goal of the trial is to enhance surveillance in areas that have long been under-monitored, especially around key subsea infrastructure like fiber-optic cables and power lines.
“The security situation in the Baltic is tense,” said Lt. Gen. Kim Jørgensen, Director of Danish National Armaments. “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 at a critical time for NATO, which has been responding to a series of incidents involving damage to maritime infrastructure. These include the 2022 Nord Stream pipeline explosions and the rupture of at least 11 undersea cables since late 2023. The most recent disruption, in January, severed a fiber-optic connection between Latvia and Sweden’s Gotland Island.
The deployment also unfolds in the context of past tensions between Denmark and the U.S. — particularly during Donald Trump’s presidency, when his administration expressed interest in purchasing Greenland, a semiautonomous territory of Denmark. Trump even suggested he would not rule out military action to seize it.
Saildrone’s Jenkins said the company had already planned to establish operations in Denmark before Trump’s reelection and declined to comment on the Greenland issue, stating that Saildrone does not engage in politics.
Some maritime incidents have been linked to Russia’s so-called “shadow fleet” — aging oil tankers that operate under murky ownership structures to evade international sanctions. In one case, Finnish authorities seized the vessel Eagle S in December after it allegedly damaged an underwater power cable between Finland and Estonia using its anchor.
Western governments continue to accuse Russia of conducting hybrid warfare, targeting both land and maritime assets.
In response, NATO is developing a multi-layered maritime surveillance network. This system combines autonomous surface vessels like the Voyagers with conventional naval ships, satellites, and seabed sensors.
Pakistan rejects reports of missile supply to Iran
Peter Viggo Jakobsen of the Royal Danish Defense College said maintaining continuous maritime presence with traditional ships is prohibitively expensive. “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,” he explained.
Jakobsen emphasized that the goal is to maintain constant monitoring of potential threats through a more cost-effective, layered approach.