Foil
An underwater wing on a vertical mast that lifts the board out of the water once you reach foiling speed.
Also known as: hydrofoil
A foil is a hydrofoil — an underwater wing mounted to the bottom of your board on a vertical mast (typically 60–95 cm). At low speed it’s just drag. At foiling speed (often as little as 8 kt of wind) it generates enough lift that the board climbs entirely out of the water and rides on the foil alone.
The feeling is famously magic: no more chop, no spray, near-silent flight a foot above the surface. Wind requirements drop dramatically — wing foilers happily session 8–10 kt where a windsurfer would sit on the beach.
Foiling adds its own demands:
- Steeper learning curve (balance is 3D, not 2D)
- Real consequences if you fall on the foil itself
- More gear: foil, mast, fuselage, front wing, stab — all tuneable
- Stronger requirement for clear, deep water at launch
Once foiling clicks, most riders never go back. Wing foil exists almost entirely because of it.
Related reading: Kite Size from Forecast, Tides for Kiters.
Related terms
- Pump Driving the foil up and down with your legs to generate forward speed — used to take off and to keep flying in a lull.
- Planing When a board rises out of the water and skims across the surface instead of pushing through it — the threshold that turns slogging into flying.
- Downwinder A point-to-point session ridden with the wind — start upwind, ride downwind, get a lift back.