The Supermarine Walrus was a catapult-launched, biplane amphibian with pusher propeller, developed from the Seagull. The Prototype desigjnated the Segull V had one 635hp Pegasus IIM2 engine, it was initially built as a private venture, this then became a production model for RAAF. The first production models in 1935 were the Walrus Mk I, redesignated from the Seagull V for service with the RAF and FAA; some fitted with ASV radar. The Walrus was rather rectangular in outline, and did not show that it was built by the same manufacturer as the Spitfire. It was the standard catapult- launched reconnaissance and SAR (Search And Rescue) aircraft for some time. 740 were built between 1936 and 1944.