Swedish firm tests unique unmanned hydrofoil craft

A Swedish composites manufacturer just flew a boat that doesn’t touch the water.

Aston Harald Composite completed the first test flight of an unmanned hydrofoil vessel called GhostFoiler in the waters of Stockholm last week, weaving among ferries and recreational boats in the city’s archipelago. The company said the craft performed well for a first attempt, after resolving grounding and shielding issues that came up during setup.

“The first flight is always special,” the company said. “The test went according to plan, after sorting out the usual grounding and shielding issues, and we were soon flying among ferries and recreational boats in the Stockholm archipelago. It flew well!”

Hydrofoils are not new. Boats mounted on underwater wings have existed for more than a century, using the same lift principle that keeps an airplane in the sky, but applied to water instead of air. What makes GhostFoiler different is that nobody is standing on it. The vessel has to sense the water’s surface, its own height above it, and constantly adjust to stay stable, all without a human balancing on deck the way a foilboard rider would. That’s a substantially harder control problem than keeping a hull floating on the water in the conventional way, and it’s the reason foiling drones have lagged behind ordinary drone boats.

The technology GhostFoiler runs on traces back nearly two decades to a student project at KTH Royal Institute of Technology in Stockholm. In 2008, naval architecture professor Jakob Kuttenkeuler led a group of 15 students in building an early electric hydrofoil board called Evolo, widely credited as one of the first electric hydrofoils ever built and an ancestor of the eFoil boards now sold commercially around the world. Kuttenkeuler has continued that research at KTH’s Maritime Robotics group, developing Evolo into an experimental hydrofoiling testbed for autonomous control systems, sensor fusion and navigation. That academic work was spun out commercially under the name EvoloFoil, which built the hydrofoil rig and flight-control system now flying on GhostFoiler.

Aston Harald Composite, a small Swedish composites manufacturer, built the physical vessel itself. The company designed the hull and manufactured its composite structures, including a carbon-fiber catamaran hull, the lightweight, high-strength material more commonly associated with racing sailboats and aircraft than with typical drone boats. Propulsion comes from two 10-kilowatt electric outrunner motors built by another Swedish company, Zparq AB, which Aston Harald described as extraordinarily quiet, a useful trait for a vessel that may eventually be used for reconnaissance or surveillance work.

The demonstrator is now headed to Portugal, where it will operate under the GhostFoiler name as part of Team Sweden at NATO’s REPMUS 2026 exercise. REPMUS, short for Robotic Experimentation and Prototyping using Maritime Uncrewed Systems, is an annual NATO exercise where allied nations bring uncrewed underwater, surface and aerial systems to test them together in realistic maritime scenarios, making it one of the main venues where early-stage technology like GhostFoiler gets evaluated alongside systems from established defense contractors.

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