The Blackburn T.9 Shark was designed and built, initially as a private venture, to Air Ministry Specification S.15/33 for a torpedo-spotter-reconnaissance aircraft to be operated by the Fleet Air Arm. It had a crew of three, with the observer/wireless operator and gunner sharing the second cockpit (open on Mks I and II, enclosed on Mk III). Armament consisted of one fixed, forward-firing .303 in (7.7 mm) Vickers machine gun, plus a .303 in (7.7 mm) Vickers K machine gun or Lewis Gun mounted on a Scarff ring in the rear cockpit, with provision for a torpedo or equivalent bombload carried externally. The Blackburn "B-6" prototype with a Armstrong Siddeley Tiger IV was flown at Brough on 24 August 1933. The aircraft subsequently began Naval aviation tests at the Aeroplane and Armament Experimental Establishment (A&AEE), RAF Martlesham Heath on 26 November 1933.