Curtiss and Porte's plans were interrupted by the outbreak of World War I. Porte sailed for England on 4 August 1914 and rejoined the Navy as a member of the Royal Naval Air Service. Appointed Squadron Commander of Royal Navy Air Station Hendon, he soon convinced the Admiralty of the potential of flying boats and was put in charge of the naval air station at Felixstowe in 1915. Porte persuaded the Admiralty to commandeer (and later, purchase) the "America" and a sister craft from Curtiss. This was followed by an order for 12 more similar aircraft, one Model H-2 and the remaining as Model H-4's. Four examples of the latter were assembled in the UK by Saunders. All of these were similar to the design of the "America" and, indeed, were all referred to as "America"s in Royal Navy service. The engines, however, were changed from the under-powered 160 hp Curtiss engines to 250 hp Rolls-Royce Falcon engines. The initial batch was followed by an order for 50 more (totalling 64 "Americas" overall during the war). Porte also acquired permission to modify and experiment with the Curtiss aircraft.