Discover how this all-electric watercraft sails above the surface
In May 2023, car manufacturer BMW unveiled its new, all-electric foiling watercraft called the Icon, a 13.5-metre-long vessel that relies entirely on battery power. Like other hydrofoil vessels in the ocean, the Icon uses a set of hydrofoil wings and propellers for motion. However, instead of fossil-fuelled motors, propellers are spun by two 100-kilowatt electric motors that are supplied by six batteries beneath the watercraft. Much like the wings of an aircraft, hydrofoils such as the Icon use underwater wings that reduce the amount of drag a vessel experiences, increasing speed and fuel efficiency. They achieve this by utilising Newton’s third law of motion, which states that when one object exerts a force on another object, the second object exerts an equal and opposite force on the first. For hydrofoils, this equates to the force pushed down on the water and the water’s equal returning force, which keeps it stable while it sails.
The curved shape of a hydrofoil wing is what gives it its hydrodynamic abilities. While moving, water has to travel faster over the longer top side of a hydrofoil wing than the water moving beneath it. As water rapidly passes over the top of the wing, its pressure decreases – a phenomenon known as Bernoulli’s principle. The pressure below the wing remains high, which causes the wing to lift upwards. When the force of the lift is greater than the weight of the vessel and the force it applies on the water, the hull of the vessel will rise above the surface and appear to fly above the waves. Thanks to the Icon’s hydrofoil wing and hull design, BMW and partner TYDE claim that the energy requirement is reduced by up to 80 per cent compared to other hydrofoil designs. This gives it a range of more than 50 nautical miles, which is around 58 miles.
6 HYDROFOIL To extend battery power, hydrofoils have been designed to generate less drag during movement.
