Felixstowe F . 2 The Felixstowe F . 2 was a 1917 British flying boat class designed and developed by Lieutenant Commander John Cyril Porte of the Royal Navy at the Seaplane Experimental Station , Felixstowe during the First World War adapting a larger version of his superior Felixstowe F . 1 hull design married with the larger Curtiss H12 flying boat . The Felixstowe hull had superior water contacting attributes and became a key base technology in most seaplane designs thereafter . Design and development . Before the war Porte had worked with American aircraft designer Glenn Curtiss on a flying boat , the " America " in which they intended to cross the Atlantic in order to win the £10 , 000 prize offered by the British " Daily Mail " newspaper for the first aircraft to cross the Atlantic . Following the outbreak of war in Europe , Porte returned to England and rejoined the Royal Navy , becoming commander of the naval air base at Felixstowe where he recommended the purchase from Curtiss of an improved version of the " America " flying boat on which he had worked , the Curtiss H - 4 type , resulting in the RNAS receiving two prototype Americas and 62 H - 4s . The Curtiss H - 4s were found to have a number of problems , being underpowered with its hull too weak for sustained operations and having poor handling characteristics when afloat or taking off . One flying boat pilot , T . D Hallam , wrote that they were " comic machines , weighing well under two tons ; with two comic engines giving , when they functioned , 180 horsepower ; and comic control , being nose heavy with engines on and tail heavy in a glide . " To try to resolve the H - 4 ' s hydrodynamic issues , in 1915 Porte carried out a series of experiments on four H - 4s fitted with a variety of modified hulls , using the results of these tests to design a new hull which was fitted to the wings and tail of a H . 4 , serial number " 3580 " , with a pair of 150 hp ( 112 kW ) Hispano - Suiza 8 engines as the Felixstowe F . 1 . Rather than the lightweight boat - type structure of the Curtiss boats , the F . 1 ' s hull was based around a sturdy wooden box - girder similar to that used in contemporary landplanes , to which were attached a single - step planing bottom and side sponsons . Once modified by the fitting of a further two steps , the new hull proved to give much better take off and landing characteristics and was much more seaworthy . Porte then designed a similar hull for the larger Curtiss H12 flying boat , which while larger and more capable than the H - 4s , shared failings of a weak hull and poor water handling . The combination of the new Porte - designed hull , this time fitted with two steps , with the wings of the H - 12 and a new tail , and powered by two Rolls - Royce Eagle engines was named the Felixstowe F . 2 and first flew in July 1916 , proving greatly superior to the Curtiss on which it was based . It entered production as the Felixstowe F . 2A , being used as a patrol aircraft , with about 100 being completed by the end of World War I . Another seventy were built , and these were followed by two F . 2c which were built at Felixstowe . In February 1917 , the first prototype of the Felixstowe F . 3 was flown . This was larger and heavier than the F . 2 , giving it greater range and heavier bomb load , but poorer agility . Approximately 100 Felixstowe F . 3s were produced before the end of the war . The Felixstowe F . 5 was intended to combine the good qualities of the F . 2 and F . 3 , with the prototype first flying in May 1918 . The prototype showed superior qualities to its predecessors but the production version was modified to make extensive use of components from the F . 3 , in order to ease production , giving lower performance than either the F . 2A or F . 5 . Operational history . The Felixstowe F . 2A was widely used as a patrol aircraft over the North Sea until the end of the war . Its excellent performance and maneuverability made it an effective and popular type , often fighting enemy patrol and fighter aircraft , as well as hunting U - boats and Zeppelins . The larger F . 3 , which was less popular with its crews than the more maneuverable F . 2a , served in the Mediterranean as well as the North Sea . The F . 5 did not enter service until after the end of World War I , but replaced the earlier Felixstowe boats ( together with Curtiss flying boats ) to serve as the RAF ' s standard flying boat until being replaced by the Supermarine Southampton in 1925 .