“What differentiates it from other wind solutions,” says Bernatets, “is that the wing is not just pulled by the wind and countered by the ship.” Instead, it flies in figure-of-eight loops, which multiply the pulling effect of the airflow to give what he calls “crazy power.”

That’s an innovation over square-rigged ships, sure, but not so much over fore-and-aft-rigged ones (where the sails act like aerofoils).