Lt., later Sqn. Cdr., John Porte returned from Curtiss to England on outbreak of First World War and persuaded Admiralty to adopt Curtiss flying-boats. As commander of RNAS Felixstowe, location of HM Seaplane Experimental Station, decided 1915 to design improved single-step hull for Curtiss boats, resulting in F.1. This led to F.2 series, including about 100 F.2A, and about same number of improved F.3 and, starting in late 1918, F.5, standard RAF boat until 1925 and as Liberty-engined F-5L made in quantity in US and Canada. British total F.2/3/5 about 513, almost all delivered 1918 or later. Other types, large Porte Baby (11 built) and even bigger Felixstowe Fury (September 1918).