Coming at the end of a long line of capable single-engined flying boats and amphibians, the Walrus was actually the product of a Royal Australian Air Force requirement for an updated and more robust version of their existing Supermarine amphibian, the Seagull III, which had proved so successful. The new aircraft, which would become known as the Seagull V, would need to have the capability to be catapult launched from Royal Australian Navy cruisers, so the wooden hull of the earlier version was replaced with a strong metal design, with additional stainless steel forgings for the catapult spools and mountings.