The "Seawanhaka Rule" was instituted by a yatch club located in what city?
Gypsy (catboat):  Her design was influenced by the "Seawanhaka Rule", instituted at the Seawanhaka Corinthian Yacht Club to govern important characteristics of racing boats. Seawanhaka Corinthian Yacht Club: The Seawanhaka Corinthian Yacht Club is one of the oldest yacht clubs in the Western Hemisphere, located in Centre Island, New York, with access to Long Island Sound.
Centre Island, New York