After a 19-year absence, the America's Cup returns to the sporting calendar, but the giant J-Class yachts, considered too expensive for the post-war period, were abandoned in favour of the more agile and manageable 12-Meter SI (born under the International 12-Meter Rule of 1906). The Deed of Gift was then amended, and the minimum waterline length reduced from 65 feet (19.81 meters) to 44 feet (13.41 meters). In 1970 the NYYC accepts two simultaneous challenges for the first time (from France and Australia), thus inaugurating the Challenger Selection Series we know today. After 132 years of uninterrupted dominance, America lost the Cup. It happened in 1983 when the 12 M Australia II defeated the U.S. Defender Liberty, skippered by "Mr. America's Cup" Dennis Conner. Overcoming the shock of his defeat, Conner managed to regain the trophy in the following edition of 1987 under the colors of the San Diego YC.

.