In April 1917, the
British Admiralty developed a requirement for a long-range patrol flying boat to work in support of the Fleet, and issued Specification N.3(b) (later reissued as Air Ministry Specification XXX) to meet this need. This resulted in designs from
Vickers (for the
Valentia) and Shorts of
Rochester, who, although better known at the time for
floatplanes, had gained experience in flying boats, building
Felixstowe F.3 and
F.5s under licence from April 1917. Short Brothers received an order for three prototypes just after the
Armistice ended the First World War. Short's design, the N.3 Cromarty, was a large, twin-engine
biplane. It was powered by two
Rolls-Royce Condor engines, and had a similar, but larger hull to that of the Felixstowe flying boats, with a biplane tail. It featured a side-by-side cockpit for the two pilots, a large box cockpit for a gunner, who was armed with a
COW automatic cannon, and a dorsal position for another gunner armed with a
Lewis gun. Production of the prototypes started in February 1919, but the second and third were cancelled before completion, with the first prototype eventually being launched on 21 March 1921, being first flown by
John Lankester Parker on 11 April 1921. ==Operational history==