# EFoil

The term eFoil (also E-Foil) stands for an electrically powered hydrofoil board with an integrated electric motor and a rechargeable battery. The hydrofoil construction, which is attached to a mast under the board, enables dynamic buoyancy at sufficient speed, whereby the board begins to lift itself from the surface of the water and glide over it almost silently and without waves.

## Functionality

→ Main article: Dynamic buoyancy, Dynamic lift
When the electric hydrofoil board reaches a sufficient speed, the displaced water volume of the hydrofoil creates a negative pressure under the water surface and enough buoyancy to lift the hull and the entire board above the water. This reduces contact with the water surface and drag and enables greater maneuverability. The eFoil differs significantly from jetsurfing, where the board rests on the surface of the water throughout the ride.
The rider regulates the power of the electric motor via a Bluetooth-controlled remote control and, once the board begins to lift out of the water, can control and regulate the height of the wings and turns by shifting their weight.

## Components

An eFoil consists of several components that enable it to “fly” over the water:

### Board

The board of an electrically powered hydrofoil is similar to that of a surfboard or kiteboard, although it is usually heavier and more stable. At the same time, there is space for the battery and other electronics at the rear end, which are protected by the board's water resistance. Along with the integrated technology, the boards from eFoils have a comparably large volume. In contrast to conventional surfboards, which are usually made of rigid foam coated with polyester or epoxy resin, high-quality boards for an eFoil are preferably manufactured using solid carbon fibers in addition to glass fiber-reinforced plastic and aluminum.

### Hydrofoil

The mast (or centerboard) attached to the underside of the board connects the board floating on the water surface with the hydrofoil at the lower end and the drive. Depending on the quality of the mast, it is often made of carbon or aluminum. Two wings are attached to its lower end - a smaller front wing and a larger back wing, which, depending on their size, determine the maneuverability and strength of the buoyancy.

### Drive

Whereas in kitesurfing, wingfoiling or pump foiling, wind, waves or muscle power are responsible for propulsion, eFoils are equipped with an electric drive. This is located in the form of a propeller at the rear lower end of the hydrofoil structure. The impeller, which is surrounded by a protective housing, is increasingly being used, thus reducing risks and wear. Current models reach maximum speeds of between 50 and 60 km/h (31 to 37 mph).

### Battery

The eFoil is powered by a built-in lithium-ion battery, which, depending on its size and capacity, can last up to two hours.

## History

The manufacturer Lift Foils from Puerto Rico claims the title of inventor of the eFoil and launched the first series of “Lift eFoils” on the market in 2018. At around the same time, however, there were already other models from manufacturers such as the German manufacturer Aerofoils and the Australian competitor Fliteboard. Ultimately, it is not clear who the actual inventor of the eFoil is.