First flown in May 1933, the Vought XF3U-1 prototype was designed and built to meet a US Navy requirement for a two-seat fighter biplane, and was powered by a 522kW Pratt & Whitney R-1535-80 engine. However, after completion of testing, the company was requested to modify this conventional aircraft into a scoutbomber under the designation XSBU-1, which differed from the XF3U-1 by having strengthened wings of increased area, greater internal fuel capacity and provision to carry a 227kg bomb beneath the fuselage. Following further tests from June 1934, an order was placed for 84 production SBU-1 aircraft, and deliveries began on 20 November 1935. Generally similar to the prototype, these were followed by the SBU-2 (40 built) which differed by introducing the 559kW R-1535-98 engine. The XSBU-1 prototype was converted for use as an engine testbed, and under the company designation V-142A a small number were built for export to Argentina. The last biplane to be designed and built by Vought for the US Navy, the type was still in service with the US Navy Reserve in 1941.