bignick
Active member
A foil with a small platform area needs to operate at a high angle of attack at low speeds to generate lift equal to the weight of the boat. A large foil would operate at a smaller AoA to generate the same lift force. As speed doubles, the lift on any foil will quadruple, so the small foil will need to reduce AoA faster than the large foil, as the lift required remains the same.