The Supermarine S.6 is a British racing seaplane that was built by Supermarine in the 1920s. It was designed for the Schneider Trophy contests of the late 1920s and 1930s, and two S.6 racers were entered into the 1929 Schneider Trophy at Calshot, England. One of the S.6s, piloted by Flying Officer H.R.D. Waghorn, won the race at a speed of 328.63 mph (528.88 km/h), while the other was disqualified after turning inside a marker pole. However, it still set world closed-circuit records for 50 and 100 km during its run. In response to a public outcry, the British government restored funding for the 1931 Schneider Trophy race, and two more S.6s, known as S.6Bs, were built with more powerful engines. The two existing Supermarine S.6s were also modified and designated as S.6As. All four planes were brought up to a similar standard and equipped with Rolls-Royce R engines. During training for the 1931 contest, one of the S.6As, N247, was destroyed in a fatal takeoff accident, leaving only the two S.6Bs and the surviving S.6A to compete in the race.