The Origin of e-foiling

How a student project at KTH invented the world's first e-foiler

The Concept

The hull was a carbon fibre sandwich board, its shape loosely inspired by a classic Riva motorboat. Below it, a strut connected to a hydrofoil assembly carrying both the main lifting foil and a smaller rear stabiliser. A 3 kW electric motor drove a propeller fully submerged beneath the hull, which kept noise low and the drivetrain out of reach.

Steering was done entirely by weight shift. No throttle stick, no mechanical controls. As the craft accelerated, the foil generated lift proportional to speed squared, and at around 8 to 10 knots the hull broke free of the water surface. From that point the craft flew on the foil alone, with drag reduced to a fraction of its displacement value and the ride becoming noticeably quieter and smoother.

Battery capacity set the practical range. The hull had been sized to keep the system buoyant with a rider, and the battery pack was housed inside it. Weight was kept low throughout: the board structure was carbon fibre, and the foil assembly was designed to be as light as the hydrodynamic loads allowed.

What Came Next

The project did not end with the prototype. Over the following years, Evolo was rebuilt and developed further at KTH's Maritime Robotics Laboratory. Each version added more capability: better sensors, more sophisticated control systems, and eventually full autonomy.

The current platform is an autonomous foiling USV that can follow GPS routes, hold position, measure altitude using radar, and stream full telemetry, all while foiling at 15 knots. The same basic concept the students put in the water in 2009.