Have you ever seen someone riding an electric surfboard across a local lake or ocean? Or perhaps you've seen Mark Zuckerberg in the press or on social media riding his eFoil while saluting the American flag or wearing sunscreen on his face. Although the technology underlying what is happening here is quite astounding, it also has a long scientific and historical background that stretches back to the late 1800s.
This article will explain what an eFoil is and how it functions. We describe how to use one of these boards to soar above the water and the differences between the battery-powered eFoil and the non-motorized surfing boards.
What is an eFoil — How Does It Work?
Let's start by defining hydrofoil. A surface-piercing hydrofoil and a submerged hydrofoil are two different sorts, but both have the same effect of raising a boat's hull out of the water so that it flies above the water.
Since 1869, when British patents were discovered with "wedge shape components" modified to a boat model to efficiently raise the vessel and minimize drag, individuals have been experimenting with the notion. Later, in 1919, Alexander Graham Bell (yep, the same person who created the telephone) created a hydrofoil boat that was successful and smashed the previous world record of 70.85 mph.
After then, hydrofoils were used by the military to hover above the water for a while. However, in more recent times, surfers have decided to combine science and technology for amusement.
What is the science behind feeling like Jesus on one of these boards and attaining flight? A large portion of it is based on Bernoulli's Principle, which states that pressure falls as fluid speed rises. You'll see that our submerged foil wing looks like a little plane when you look at it underwater. This is because a hydrofoil creates a lift very similar to how a plane does.
The pressure on the top of the wing lowers while the pressure beneath the wing rises when you start to gain speed and cut through the water. This, together with the form of the wing, essentially generates lift.
A hydrofoil vessel also requires some type of horizontal propulsion to raise and stay elevated, much as how an aircraft stays in the air, which uses a combination of this concept plus its engines to provide horizontal thrust.
Hydrofoil vs eFoil
This is where we begin to discuss the distinction between an efoil, a hydrofoil board outfitted with a battery and propeller, and a conventional foil, like the one Zuckerberg, sported on July 4th.
Both can lift you off the ground and carry you above the water, but normal foils have a more straightforward construction because they just consist of the board itself, a mast that is submerged in the water, and a foil wing. However, surfers who jump on foil boards must find alternate means of obtaining horizontal thrust as there is no motor to move it forward.
Regular foilers frequently pick up the ability to paddle into a wave, surf it, and then use the momentum and pumping motions to spin completely around and catch another wave. Foiling has the advantage of far reduced drag and resistance as well as the ability to ride considerably smaller swells, such as the rolling waves you see in the distance just before they smash.
Towing yourself behind a boat or a jet ski so you can ride the wake or get pushed onto a wave is an easier kind of foiling. For more experienced riders who are already involved in kite sports, utilizing a kite sail or even a kite wing is a more difficult approach to foil. On foils, professional riders like Kai Lenny do a wide variety of feats including backflips and 360s.