Heliographon that topic of #flying πΈπ€
"Like F1 cars with airfoils, a boat can have hydrofoils - wings curved up top and flatter underneath, so when they move through a fluid the pressure reduces on top and increases underneath, producing lift.
Traditional hydrofoils make for a bumpy ride, but put underwater the speed gains are huge while the ride stays smooth, smooth enough to create nearly no wake.
Right now most waterways near cities are no-wake zones, so powered boats have to go slow. That leaves waterways underused, e.g. compared to roads. Underwater hydrofoiling could change that, plus also make the boat quieter, and cut energy usage by up to 80%. First hydrofoil #ferries are currently running in #Sweden."