Underwater hydrofoils bring passenger boats up to speed.

Like an F1 car with airfoils, a boat can have hydrofoils - ‘wings’ that are curved on top and flatter underneath, so when they move through fluid the pressure reduces on top and increases underneath, producing lift. Traditional hydrofoils make for a bumpy ride, but put them underwater, and the speed gains are huge while the ride stays smooth… smooth enough to create nearly no wake.

Right now most waterways in and near cities are no-wake zones, which means boats have to go slow. That makes waterways underused, compared to, say, roads, something that underwater hydrofoiling could change. The foiling also makes the boats quieter, and cuts energy usage by up to 80%, which is huge (and very helpful when your boat is also electric).

The first hydrofoil ferries are currently moving from concept to reality, as firms like Sweden’s Candela start delivering to cities around the world.