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What is Foiling
In sailing, foiling refers to lifting a boat, board or catamaran out of the water using hydrofoils – underwater-mounted lifting wings. Instead of being slowed by water friction, the craft glides over the surface, supported by the foils. What was still considered an experiment a few decades ago is now a fixed part of Olympic sailing, professional series and increasingly grassroots sport. Anyone who wants to understand regatta sailing cannot ignore foiling.
The Basic Idea: From Displacement to Flying
Classically, a boat sails in displacement mode: the hull displaces water and creates friction in the process. The faster the boat goes, the greater this resistance becomes. Hydrofoils break through this principle. As soon as there is enough speed and lift, the hull rises – often completely – out of the water. What remains are slim foils and occasionally minimal hull contact.
The decisive advantage lies in reduced water friction. A foiling boat can achieve significantly higher speeds in the same wind than a comparable displacement boat. In regatta sailing this means: different course routing, different manoeuvres, different tactics – and a completely new feel on the water for the crew.
From Displacement to Foiling Mode
The Physics Behind Foiling
Lift and Speed
A hydrofoil works on the same principle as an aircraft wing: water flows over the profiled surface, creating low and high pressure and thus lift. Flow speed is crucial. Only above a certain minimum speed – the so-called take-off – does the boat reliably lift out of the water.
Stability and Balance
In foiling mode, the crew no longer steers primarily through hull displacement, but through:
- Foil trim – angle and depth of the lifting wings
- Weight shift – fore-aft and sideways
- Sail pressure – drive and depower
- Rudder and steering – course and height control
Balance is finer and more responsive than in classic sailing. Small errors lead more quickly to loss of height or capsizing – at the same time, entirely new manoeuvre possibilities open up.
Important: Foiling is not purely a question of speed. Taking off too early or too late often costs more time in a regatta context than is gained through pure boat speed.
Foiling vs. Classic Sailing
Where Foiling Appears in Regatta Sailing
Foiling is no longer a niche topic. It spans from the Olympic single-handed windsurfer to America's Cup monohulls:
Olympics and World Cup
Since the 2024 Olympic Games in Paris, IQFoil (windsurf foil) and Formula Kite (kitefoil) have been Olympic disciplines. The Nacra 17 has been foiling as a mixed catamaran at the highest level since Rio 2016. These classes define elite sport and shape youth and qualification pathways.
Professional Series and Spectacle Formats
SailGP with the F50 catamarans and the America's Cup with AC75 monohulls have made foiling a mass phenomenon. Short races, high speeds and spectacular manoeuvres make foiling media-friendly and attract sponsors.
Grassroots Sport and Getting Started
Classes such as WASZP, Techno Wind Foil or club foiling programmes lower the entry barrier. Many sailing clubs now offer foiling courses – often after classic dinghy training in the Optimist or ILCA.
Foiling Disciplines by Entry Level
Key Foiling Terms
Anyone who wants to understand foiling should know these terms:
- Hydrofoil / foil – The underwater-mounted lifting wing with mast and stabiliser if applicable
- Take-off – The moment when the hull lifts out of the water
- Foiling height – The flying height above the water surface
- Pitch / roll / yaw – Fore-aft tilt, sideways tilt and rotation around the vertical axis
- Ventilation – Air ingestion at the foil that destroys lift and control
- Cavitation – Vapour bubble formation at very high speeds on the foil edge
- Landing – Controlled lowering of the hull back into the water
Foiling Classes at a Glance
You can find a detailed class comparison in the article Foiling Classes.
Technique and Process in Foiling
Preparing for Take-off
Take-off does not succeed through pure acceleration, but through coordinated interplay:
- Build sail pressure and hold a stable course
- Shift weight aft to unload the bow
- Trim foil angle so that lift is generated without lifting off too early
- On catamarans: unload both hulls synchronously
Stable Foiling
In flight mode: small movements, big effect. The crew responds to wind gusts with depower and weight shift, not with abrupt rudder movements. Height and course are maintained through the interplay of sail, foil and body weight.
Manoeuvres in Foiling Mode
Tacking and gybing while foiling require precise timing. The goal is to let the hull sink into the water only briefly or not at all. Professionals perform foiling tacks and foiling gybes where the boat stays on the foils throughout – a decisive time advantage in tight regatta situations.
Foiling Tack in 6 Steps
Safety and Risks in Foiling
Foiling is more demanding and carries different risks than classic sailing:
- Higher speed in collisions or falls
- Sharp carbon edges on foils and hull
- Ventilation can lead to uncontrolled crash
- Capsizing from greater height with higher impact energy
Warning: Foils are hard to see underwater. Distance from other boats and swimmers is especially important when foiling. Life jacket and helmet are mandatory in most foiling classes.
Checklist: Safety Before Foiling Training
- Life jacket and helmet checked and worn
- Foil screws, mast and connections inspected
- Wind strength and gust conditions suitable for take-off
- Training area clear of swimmers and obstacles
- Safety boat or support person informed
- First aid equipment available on shore
- Ventilation and landing technique discussed on shore beforehand
Getting Started in Foiling – A Sensible Path
Foiling requires solid sailing fundamentals. A proven entry path:
- Classic dinghy experience – balance, wind sense and manoeuvres in Optimist, ILCA or 420
- First foiling experience – often via windsurf foil, WASZP or club training boat
- Specialisation – choice of a foiling class depending on physique, budget and regatta goals
- Regatta entry – club regattas, then national and international events
Tip: Many sailors start via windsurf foiling or kitefoiling because take-off is often more intuitive there than in boat foiling. Balance skills transfer well to foiling dinghies and catamarans.
Foiling and Regatta Tactics
Foiling fundamentally changes tactical decisions:
- Minimum wind: fields split more strongly – those who can take off often win entire sides of the course
- Manoeuvre cost: a failed foiling tack costs more time than a classic tack
- VMG: optimal course and speed differ from displacement sailing
- Starts: position and acceleration to the line are decisive for early take-off
Those who know courses and VMG in classic sailing must recalibrate many assumptions for foiling.
Future: Foiling as the Standard
Foiling is not a passing fad. World Sailing, class associations and boatyards continuously invest in foiling technology. New materials, better foil profiles and safer entry-level classes make foiling more accessible. At the same time, professional formats that use foiling as a hallmark are growing.
Foiling in Olympic Sailing
Frequently Asked Questions About Foiling
Is foiling more dangerous than normal sailing?
With proper equipment, training and wind limits, foiling is manageable. The risks are different – higher speed and carbon foils require more respect and preparation.
From what age can you start foiling?
Many clubs start young sailors from age 12–14 with entry-level foiling classes such as WASZP or Techno Wind Foil, provided solid sailing fundamentals are in place.
Do I need my own foiling boat?
For getting started, club boats or rental equipment are often sufficient. For competition, your own class-compliant setup is usual.
Can you foil in light wind?
That depends on the class. Formula Kite often takes off from 6 knots, boat foiling usually from 8–10 knots. Below take-off speed, the boat remains in displacement mode.
Is foiling worthwhile for recreational sailors?
Yes – foiling offers a unique feel on the water and is growing in grassroots sport. Regatta entry is optional, but many foilers sail without competitive ambitions too.