The J-class yacht, in the 1930's, embodied new technology and professionalism in yachting and heralded in the modern era in the America's Cup. Designers introduced aeronautical technology in the engineering of hulls and rigging. Aluminium masts and the 'Park Avenue' boom were introduced to save weight and aid in sail trimming. The men who raced them were professional, not amateur, and the skippers such as Harold S. Vander built...