United States Hydrofoil Association

Hydrofoil Description

Hydrofoiling is an exciting sport that has things to offer at all levels of expertise. From riding and enjoying a smooth ride in rough water to performing aerial tricks anywhere behind the towing water craft. Come and join us in the exciting new sport!

A hydrofoil is made up of three major assemblies:

• Seat Tower - This is the where you sit on the ski. Typically made of aluminum, there are models with a shock and without a shock. These are called "Shock Towers" and "Rock Towers." The seat comes with a safety belt that keeps the rider from being released from the seat/ski.
• Board - The board is typically made of fiberglass or carbon fiber resin molded ski. There are two bindings with safety straps that keep the rider's feet from being released from the board. There are bindings that can be adjusted up and down the board for different rider leg lengths.
• Foil Assembly - The foil assembly consists of three major parts. The strut/fuselage which acts as a rudder to guide the rider in the direction they turn their knees/body. The front wing which provides the lift and enables the rider to rise/jump the ski off the surface of the water. Lastly, there is the rear wing which stabilizes/counterbalances the lift from the front wing. There are many different kinds of foil configurations and these configurations are critical for how the ski reacts and rides in the water. The foil assemblies are typically made from cast or billet aluminum.

A hydrofoil is towed behind some type of watercraft with a driver and a spotter. The rider straps into the hydrofoil and secures the safety straps on the seat tower and the bindings. Starting in deep water, they lean back to keep the tip of the board out of the water and then once the board begins to plane, the rider leans forward to keep the hydrofoil from leaving the water. Once the rider is at a speed high enough to provide lift from the foil assembly, they will bring the board off the surface of the water at which time "flight" begins. This is when the "balancing" act begins. To bring the board off the water, the rider leans back and to bring the board down to the water they lean forward. The rider steers the hydrofoil by moving their knees in the direction they want to go.

One of the benefits of riding a hydrofoil is that the rider can ride above the waves which makes it a great water sport in rougher water. In fact, the rider is usually limited by speed the boat can go. If the water is too rough, the boat may not be able to go fast enough for the rider to get enough lift from the foil to rise above the surface of the waves. Another benefit is the ease of riding. There is far less strength need to ride on a hydrofoil than a water ski or a wakeboard. Hydrofoils actually ride underneath the water which reduces the amount friction on the riding surface which in turn reduces the tension in the rope. A water ski, on the other hand, rides on the surface of the water where the friction is much greater (surface tension). This effect can be demonstrated when watching a rider release from the rope. A hydrofoiler will "coast" for a longer distance than a water skier or wakeboarder going at the same speed.