A sail for sailboats is described. The sail having portions wherein shape memory elements in the form of filiform members made of a shape memory alloy are incorporated, the surface area resulting from the sum of the surface areas of the portions incorporating shape memory alloy elements being between 0.01% and 50% of the surface area of the whole sail. A control apparatus is also disclosed for controlling the operation of the sail. A method is further disclosed for controlling operation of a sailboat sail.