massive 10 inch protrusion, with a smaller (almost by a third) flexible swept-back model he had copied from the shape of the rear dorsal fin of a tuna. This design had the effect of reducing drag and increasing the handling capabilities of the board; the new surfboard fin, which Greenough called a "high aspect ratio fin", was an elegantly functional piece of equipment, but took around three years to become popular. In 1964 Greenough traveled to Australia, where he showed the local surfers his wave riding style of sharp bottom turns and deep barrel rides. He influenced Nat Young, who used Greenough's fin design and won the 1966 world surfing championships in San Diego, California, thus ushering in an era in surfing history in which the Australians emerged as a dominant force. Young described Greenough as "The greatest surfer in the world today," After this first visit to Australia, Greenough shaped a board which he explained as the next step in the progression of surfing, "a fish moves when he swims… so why not make a whole board that moves when it's on a wave?" The board he created had multiple layers of fiberglass shaped like the old balsa kneeboards he rode, a glued on ridge of polyurethane foam on top of the deck near the rails and nose with the back end of the board made entirely of fiberglass; the final piece to the board was his signature "flex-fin". The board was so small and light that it was not very good to ride in small surf; only in big surf did the board reveal its performance abilities and allow Greenough to maneuver on waves with more power and speed than with previous designs—"Greenough was riding like a visitor from ten years in surfing's future. He cranked out bottom turns where his board tilted up almost 90 degrees…" In 1966 Greenough made his second board which he nicknamed the 'velo' for velocity. Movies Greenough has made multiple films in his career; he would swim out into the surf with fins and take pictures looking out from the inside of the barrel. This "barrel-vision" was regarded as a major progression in surf photography. His film, The Innermost Limits of Pure Fun, was shot using a massive 28 pound camera with a water-proof housing strapped onto his shoulder which he used to show the inside of a wave. His film was