The S.6B marked the culmination of Mitchell's quest to "perfect the design of the racing seaplane" and represented the cutting edge of aerodynamic technology for the era.

[1] Despite these predecessors having previously won the Schneider Trophy competition twice, the development of the S.6B was hampered by wavering government support, which was first promised then withdrawn, and then given once more after a high-profile public campaign encouraged by Lord Rothermere and backed by a substantial donation by Lady Houston.

The principal differences between the S.6 and the S.6B were the increased power of the Rolls-Royce R engine and redesigned floats: minor aerodynamic refinements typically aimed at drag reduction were also made.

Despite the Prime Minister Ramsay MacDonald's pledge that government support would be provided for the next British race entrant immediately after Britain's 1929 victory, official funding was withdrawn less than two months later following the Wall Street Crash; the official reason given for the withdrawal that the previous two contests had collected sufficient data on high speed flight, so further expenditure of public money was unwarranted.

[4] As ever active in aviation affairs, Lord Rothermere's Daily Mail group of newspapers launched a public appeal for money to support a British race entrant; in response, several thousand pounds were raised.

[5][6] The British government also changed its position and announced its support for an entry in January 1931; however, by this point, there were less than nine months left to design, produce and prepare any race entrant.

[5] Mitchell retained the majority of the S.6's design, his efforts being principally focused on improving the prospective aircraft's heat dissipation; speaking on a radio broadcast, he later referred to the S.6B as a "flying radiator".

Although the British team faced no competitors, due to misfortunes and delays suffered by other intending participants, the RAF High Speed Flight brought a total of six Supermarine Schneider racers to Calshot Spit on Southampton Water for training and practice.

Lt. John Boothman, attaining a recorded top speed of 340.08 mph (547.19 km/h) and flying seven perfect laps of the triangular course over the Solent, the strait between the Isle of Wight and the British mainland.

[17][18][4] The outstanding performance of the S.6B had drawn the attention of not only British military officials and aircraft designers, but internationally as well, influencing new fighter projects in, amongst other nations, both Nazi Germany and the United States.

Having been repainted in WW2 to represent S1596 in the film First of the Few, S.6A N248 remained in this guise postwar and was displayed as S1596 at various events and locations including the Southampton Royal Pier as a visitor attraction.