The Supermarine Commercial Amphibian (originally named the Supermarine Amphibian, later designated N147 by the British Air Ministry) was a passenger-carrying flying boat. The first aircraft to be designed by Supermarine's Reginald Mitchell, it was built at the company's works at Woolston, Southampton, for an Air Ministry competition that took place during September 1920. Based on the Supermarine Channel, the Amphibian was a biplane flying boat with a single engine, a wooden hull, unequal wingspans and a 350 horsepower (260 kW) Rolls-Royce Eagle engine. The front of the aircraft was designed to lift clear of the water prior to take-off. The pilot sat in an open cockpit behind two passengers.