Foilboard
A foilboard or hydrofoil board is a surfboard with a hydrofoil that extends below the board into the water. This design causes the board to leave the surface of the water at various speeds. Background. Laird Hamilton, a prominent figure in the invention of big wave tow-in surfing, later discovered the foilboard's capability to harness swell energy with the use of a jet ski, pulling the rider into a wave. The stand-up design allows the rider to glide with the moving wave by harnessing the kinetic energy with the underwater swell. Hydrofoil kiteboards allow the rider  to achieve the same result with the use of a kite. The hydrofoil minimizes the effects of choppy or rough conditions. Due to the hydrofoil's underwater characteristics, the rider can angle higher into the wind than on traditional kiteboards which ride on the surface of the water. In 2009 an Australian Inventor Brett Curtis built and rode the first paddle-in or prone hydrofoil. He posted photos on surfing forums Swaylocks and RealSurf of a friend Alex Budlevski riding the foils in 2013, 3 years before Kai Lenny made surfing hydrofoils famous. Foils are used on wind-surfboards through  design development from Neil Pryde Maui, inventors of hydrofoil sailing "windsurfing" boards. Using a moderately sized sail, a foil windboard can achieve speeds over 6 knots faster than the apparent wind. With advancements in hydrofoil design the energy required to stay on foil was reduced to levels achievable by human power alone. Kai Lenny pioneered a technique now called "pumping" in which the rider shifts their weight over the axis of rotation, driving the foil through the water column which generates lift. In 2009 in Prof. Jakob Kuttenkeuler and Prof. Stefan Hallström, both from the Royal Institute of Technology, KTH , Stockholm, Sweden published their Evolo project. Evolo was a vehicle invented, designed, and built by 15 masters students studying Naval Architecture and Lightweight Structures who received an assignment from the two professors (above) which combined an electric motor with a hydrofoil into a person-watercraft that was controlled with weight shifting and motor speed. In October 2016 Dan Montague former head of R&D at the Naish International posted a youtube video from Jetfoiler showing an electric hydrofoil surfboard (now commonly known as an eFoil) flying above the water in Fiji. In 2017, Lift Foils, a small company in Puerto Rico , developed the first commercially available electric-powered hydrofoil surfboard; it went into production in 2018. The board has an electric motor, propeller, and carbon fiber foils and carbon fiber mast below the waterline. A rechargeable lithium battery and electronic speed controller are encased in a waterproof compartment inside the carbon fiber board. Motor speed is controlled by a wireless handheld Bluetooth remote with a trigger actuated accelerator. After Lift many other companies brought efoils to the commercial market, including Fliteboard (Australia), Waydoo (China), Takuma (France/Japan), Foil (USA), MSLR (Canada), Flying Rodeo (Slovenia), ArtFoils (Russia), PWR-Foil (France). There are  efoil DIY maker/builder communities online. Use. In 2021 a father and son crossed the English Channel on propeller-powered hydrofoil boards. They covered 23 miles in one hour and 44 minutes at speeds of up to 35mph on a single battery charge, arriving with 4% charge left.