The 6 Metre Class (www.6metre.com) and the North American Association (www.6mrnorthamerica.com) support racing these boats whose measurement formula dates back to 1907; four of the boats here are from 1930, 1931, 1934, and 1938. The rule has evolved over the years and the most “modern” versions have keels with winglets, trim tabs, etc.
All video taken with a hand-held iPhone 6s at 4k, chopped down to HD with FCPX.