How Does Foiling Work? The Technology That Makes Boats Fly

The foil is a kind of wing that ‘flies’ beneath the surface of the water, usually shaped like a ‘T’ or a ‘V.’ It relies on the principle of hydrodynamic lift—the same one behind aerodynamics, but applied to water. As the boat accelerates, the foil generates an upward force that lifts the hull. 

This drastically reduces the wet surface and, consequently, drag. That’s why boats become much faster. And when applied to a motorized vessel, the foil allows for lower energy consumption, offering a completely new sailing experience with the sensation of truly flying over the water. 

Foiling delivers higher performance compared to traditional boats, as it reduces water resistance and allows vessels to reach higher speeds with less power. This translates into: 

• Lower fuel consumption and optimal energy efficiency for motorboats; 
• Speeds that exceed the actual wind speed for racing sailboats. 

Foil also provides greater comfort and stability. When the boat ‘flies’ above the water, waves and ripples are felt much less. Navigation becomes quieter and smoother, with minimal hull impact on the surface. 

There are different types of foils, but the main ones are: 

• T-Foil boats: more efficient, especially in racing (for example, used on AC75s, the America’s Cup yachts). However, they require active control and constant adjustments from the crew.
• V-Foil boats: more stable hydrofoils, ideal for commercial transport. 

Foil technology is also applied to passenger maritime transport. Today, major progress has been made with the development of electric ferries equipped with foils, capable of combining sustainability with comfort. These vessels consume minimal energy while enabling faster travel. 

Foiling applied to passenger transport brings several advantages: 

• Flying above the water reduces waves, vibrations, and noise, giving passengers a smoother and more comfortable journey.
• The near-total absence of wake minimizes environmental impact on coastlines.
• When combined with electric propulsion, these vessels become a low-emission solution for public maritime transport. 

For all these reasons, foiling is establishing itself as a cornerstone of sustainable mobility for the future. 

The application of foiling to water sports has given rise to new disciplines and sailing classes: 

• Switch: launched only a year ago, but already counting over 100 boats. Many professionals competing in other classes (e.g., SailGP, America’s Cup, 49er, and Moth) have embraced this small, ultra-fast boat, making the races truly spectacular. Switch is a one-design class, meaning all boats are identical, so what really makes the difference is the skill of the helm. 
• iQFoil: the new Olympic windsurfing class. Thanks to foiling, the minimum wind required to make these boards fly has dropped significantly—adding to the spectacle. 
• Wingfoil: a completely new discipline that combines windsurfing and kitesurfing. The sail resembles a kite wing, but riders hold it directly with a boom or handles, so no long lines are needed. The board is smaller than a windsurf board, but thanks to the foil it can reach incredible speeds, jump on waves, and perform freestyle tricks. 
• eFoil: one of the most recent and innovative applications of foiling. It’s a board equipped with an electric motor and a rechargeable battery, controlled with a handheld remote, and capable of reaching speeds of up to 50 km/h. 

SLAM has launched the Ready to Fly project to tell the stories of a new generation of sailors who have chosen to take on the challenge of Switch. A series that showcases the new language of sailing—full of energy and dynamism. Among the protagonists are Mattia Cesana, Gregorio Moreschi, and Luigi Buzzi, engaged in spectacular regattas and high-speed challenges.