sentences:  The C Class Catamaran class has been experimenting and refining wingsails in a racing context since the 60s.Englishman, John Walker, explored the use of wingsails in cargo ships and developed the first practical application for sailing yachts in the 1990s.Wingsails have been applied to small vessels, like the Optimist dinghy and Laser, to cruising yachts, and most notably to high-performance multihull racing sailboats, like USA-17.