Sea Otter and postwar Seagull successors

The Walrus led into two later Supermarine amphibians. Vickers used Supermarine primarily as a design house and farmed production to other parts of the group or outside contractors, which explains how the line continued alongside Spitfire demands. The Sea Otter first flew in 1938 but did not enter service until 1944 because production capacity was limited and its Bristol Mercury engine was needed elsewhere; too few were built to replace every Walrus. An even more powerful air-sea-rescue Seagull was specified in 1940, ordered as prototypes in 1943, and did not reach prototype form until 1948, with only two built. Its Griffon engine and contra-rotating propeller offered the performance the interwar Royal Navy would have welcomed, but the dates show how a lengthy development program could leave a valid requirement behind.