This is a beautiful film of Nathanael Herreshoff single masted racing sailboat design, the J Class. The yachts Britannia, Astra, Shamrock and Endeavour are racing in Plymouth Sound. In 1903 the Universal Rule established similar classes for racing yachts and in 1930 this was adopted for the J class and new boats were built for competition in the prestigious America's Cup. The America's Cup was first awarded in 1851 to the yacht America for an Isle of Wight Yacht Race.