An aerodynamic lift enhancing gate valve assembly comprising an airfoil blade disposed at a leading edge of a sail, forming a gate between the trailing edge of the airfoil blade and the leading edge of the sail. The airfoil blade captures wind and redirects it over the cambered surface of the sail to enhance the aerodynamic lift of the sail. The pressure of the wind captured by the airfoil blade is regulated by springs or elastic bands. In operation, the chord of the airfoil blade remains substantially parallel to the chord of the sail.