Since 1851, the America's Cup has been the most prestigious trophy in the world of sailing. The America's Cup scene has always been the playground of the rich and mighty in this world, and characterized by controversial events and intrigues. It was not different in 1983, when for the first time in its history, the New York Yacht Club lost The Cup. The 1983 America's Cup winner was the 12-Metre yacht Australia II. It was equipped with a radical, innovative, winged keel that caused much upheaval in the summer of 1983. Upheaval that, occasionally, rumbles on until today.This book tells the story of the author's role in the design of the keel of Australia II. The scientific approach by two Dutch scientists (naval architect Piet van Oossanen and the author), that were involved with the design research, changed the landscape of yacht design. After the 1983 match, Cup campaigns embraced a more scientific way of designing boats. The Dutch scientists played a major role in this important change.