In early 1937, Curtiss and Vought, the Navy's two pre-war suppliers of fleet catapult scout floatplanes, were asked to submit bids for a high-speed replacement of the very successful SOC Seagull series. Navy design number 403 called for a mid-wing monoplane with a crew of two seated in tandem. The removable centerline float and outer wing floats could be replaced with optional fuselage-mounted landing gear. Because of cruiser and battleship deck and hangar space limitations, the specifications called for folding wings and wing floats all within a weight limitation of 6,350 pounds. However, the most critical design stipulation was the engine.