Foil Camber Effects in Chop – Why Positive Camber Wins in 20+ Knot Slop
Riding in high wind usually means riding in mess. The wind gusts create short-period chop that knocks your foil around.
Many riders choose "stable" reflex foils (which have a trailing edge that curves up) for these conditions. But for cutting through the slop in 20+ knots, a foil with Positive Camber (and a smaller surface area) is often superior.
Camber vs. Reflex
- Positive Camber: The foil is curved downward (like a banana). It generates high Lift Coefficient ($C_L$). It creates a lot of lift at slow speeds.
- Reflex: The trailing edge flips up. This kills some lift but adds pitch stability.
The "Small Foil" Strategy
In 25+ knots of chop, the enemy is surface area. A large foil feels every bump in the water. It bucks you off. You want the smallest foil possible.
A Positive Camber foil generates massive lift for its size. You can ride a tiny 600cm² cambered foil and still get on fly. Because the foil is so small (600cm²), it has very little wetted surface. It slices between the turbulence of the chop rather than bouncing over it.
A reflex foil produces less lift. To get the same takeoff power, you might need a 900cm² size. That extra 300cm² hits more turbulence.
Cutting the Slop
Chop is orbital energy. The water is spinning. A thin, cambered race foil pierces this energy with minimal disruption. It locks in. While a reflex foil is "stable" in terms of pitch, a small cambered foil is "stable" because it ignores the water movement. It runs on a rail.
When to Switch
- Flat Water / Speed: Reflex profiles can be faster at top-end because they manage pitch at 30 knots.
- Messy Chop / Storm: Switch to a high-camber, ultra-small foil. The high lift gets you up; the tiny size keeps you smooth.
Summary
In the chaos of high wind storm foiling, size matters more than profile. Use a profile with Positive Camber to generate the maximum lift from the minimum surface area. Shrink your foil to 700cm² or less. You will find that the chop suddenly disappears, and you are riding on a stable knife edge.