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Attacks against critical infrastructure in the Baltic Sea and throughout Northern Europe’s maritime approaches surged in 2024 and 2025. Subsea cables and pipelines that supply nations with resources and information were tampered with or damaged by unidentified hostile actors.
The Baltic and North Seas are strategically crucial waterways, but with long coastlines, vast exclusive economic zones, and limited onshore surveillance systems, coastal nations often lack the resources to continuously monitor threats. Persistent presence in open waters is crucial for navies and coast guards to maintain a credible maritime defense.
To address these maritime challenges, the Danish Ministry of Defence Acquisition and Logistics Organisation (DALO) enlisted Saildrone to operate four Voyager unmanned surface vehicles (USVs) in support of the Royal Danish Navy in the Baltic Sea for six months.
The results have been dramatic. Over the past six months, Saildrone detected more than 170,000 unique vessels, sailed over 20,000 nautical miles, and achieved 92% uptime across its fleet under a range of harsh weather and sea states, far exceeding typical availability benchmarks for unmanned systems. In the maritime domain, where manned ships often average closer to 30% operational availability over their lifetime, this level of persistence represents a step change in how presence at sea can be sustained.
That persistence is enabled by a platform designed from the outset for continuous maritime operations. The innovative design of the Saildrone Wing is at the core of that capability, harvesting wind power to supplement diesel-electric propulsion to deliver virtually unlimited range and endurance.
The six-month operational deployment for DALO followed a two-week demonstration for NATO Task Force X in the Baltic Sea, during which the Saildrone Voyagers operated alongside allied forces to evaluate persistent maritime surveillance concepts in complex and strategically sensitive waters. Saildrone was the only participant in the demonstration to successfully identify all of the simulated “red force” targets. In addition, the Saildrone Voyagers also made real-world detections, identifying non-cooperative vessels operating without AIS.
The ability to detect and classify these “dark targets” in real time—using a combination of long-range radar, AIS tracking, and onboard analytics—demonstrates the strategic value of persistent, autonomous surveillance in modern naval operations. The successful NATO demonstration also validated Saildrone’s ability to integrate with allied command-and-control structures and operate in coordination with high-speed unmanned response vessels.
Enhancing and extending the power of manned warships
Sweden and Denmark recently announced they would pursue additional ships and submarines to strengthen surveillance and protection of undersea infrastructure and territorial waters.
These new ships and submarines will remain powerful deterrence tools that can never be wholly replaced by unmanned systems. The Saildrone Voyager is designed to augment and extend those forces, continuously monitoring areas of responsibility, enabling manned vessels to be deployed where their presence will have the greatest operational effect.
When hostile actors approach critical infrastructure or maritime chokepoints, Saildrone’s presence provides clear attribution and early warning to operators, while significantly reducing the risk to human life and high-value warships. That awareness also enables those operators to make better decisions and to optimally employ their precious crewed assets.
European Operations: By, with, and through Europeans
The deployment of Voyager USVs in the Baltic Sea represents just one example of Saildrone’s commitment to supporting Northern Europe’s maritime defense.
Saildrone Denmark, a newly established European subsidiary, is strategically based in Copenhagen with easy access to the Baltic and North Seas. Saildrone is committed to serving Northern Europe and working with European industry partners; European operations will be led and staffed by local engineers, pilots, and regional security experts.
With more than 2,000,000 nautical miles sailed from the High North to the Southern Ocean, Saildrone is the only autonomous platform capable of maintaining a persistent maritime presence, closing surveillance gaps, and providing in situ maritime domain awareness.
