The definitive 1913 Model F was of wooden construction, the two-bay biplane had inter-plane ailerons on each side, fabric-covered wings and tail unit, and a carefully contoured single-step plywood-covered hull which accommodated two side-by-side in a cockpit location just forward of the wings. Power was a 56kW Curtiss O engine driving a pusher propeller. The engine being mounted on struts just below the upper wing centre-section.

The Curtiss F two-seat biplane flying boat became the Army’s first flying boat. This basic design was ordered by the US Navy, and after the United States entered World War I on 6 April 1917 it was adapted as the service’s standard primary training flying-boat, 144 more being ordered. During the war, Curtiss received so many orders for flying boats that he hired Boeing and Loughead (later renamed “Lockheed”) to build them to his specifications.

Alexandria was contracted Curtiss F-boats for USN, as the Alexandria 10, circa 1917. Thirteen were built; A2651 to 2653, A5024, and A5247 to 5256
The F was also sold to several civil owners.
The 1914 version of the Model F had rounded wingtips, a tougher hull and increased strut support for the engine to prevent it collapsing on the crew in the event of a crash.
The 1917-18 version of the Model F eliminated the original shoulder-yoke type aileron control in favour of a more conventional arrangement; and some aircraft had the ailerons transferred to the upper wing from the interplane position, span of the upper wing being extended. Several ambulance conversions flew with provision for a stretcher patient to be carried above the hull behind the cockpit. The more powerful Curtiss OXX-3 engine was fitted from 1917 onwards.
The Model F, particularly in its earlier versions, was sold to a number of foreign navies. Russia obtained a considerable number for operation in the Baltic and Black Seas. The Italians also flew the Model F and eight examples were licence-built by the Zari company at Bovisio.

Engine: 1 x 75kW Curtiss OXX-3 inline piston
Take-off weight: 1116 kg / 2460 lb
Empty weight: 844 kg / 1861 lb
Wingspan: 13.75 m / 45 ft 1 in
Length: 8.48 m / 27 ft 10 in
Height: 3.42 m / 11 ft 3 in
Wing area: 35.95 sq.m / 386.96 sq ft
Max. speed: 110 km/h / 68 mph
Range: 1370 km / 851 miles

The Curtiss Flying Boat was an early “hydro-aeroplane” or seaplane that was first concept tested by well-known aviator Glenn Curtiss in January 1912 in San Diego. By the end of the same year, Curtiss had built his first successful flying boat at Hammondsport, NY and succeeded in selling the aircraft to the Navy. The Navy first acquired five Curtiss Flying Boats, then an additional 144 for training before the original F type model was supplanted by the MF in 1918.

The C-1, the Navy’s first flying boat, was tested at Hammondsport, N.Y., by Lieutenant T. G. Ellyson on 30 November 1912. Its performance, as informally reported by Ellyson, was: “Circular climb, only one complete circle, 1,575 feet in 14 minutes 30 seconds fully loaded. On glide approximately 5.3 to 1. Speed, eight runs over measured mile, 59.4 miles per hour fully loaded. The endurance test was not made, owing to the fact that the weather has not been favorable, and I did not like to delay any longer.”

The Curtiss C-1 (changed to AB-1 in 1914) made the first catapult launch by a flying boat in December 1912.

On 27 March 1914 the original designations of aircraft were changed to two letters and a number of which the first letter denoted class, the second type within a class, and the number the order in which aircraft within class were acquired. Four classes were set up; A for all heavier-than-air craft, D for airships or dirigibles, B for balloons and K for Kites. Within the A Class, the letters L, H, B, X and C represented land machines, hydroaeroplanes, flying boats, combination land and water machines, and convertibles respectively. Thus the third hydroaeroplane, formerly A-3, became AH-3, and the first flying boat, formerly C-1, became AB-1.

The first Curtiss Flying Boat acquired by the Navy was designated C-1, before it was changed to AB-1 (A for Curtiss and B for flying boat) as the Navy began to procure aircraft from other corporations. The C-1 was based at the Navy Yard in Washington, D.C. in 1912 before moving to Guantanamo Bay, Cuba.

The first Curtiss flying-boat, tried at San Diego on 10 January, 1912, was more a hydro than a true boat. A wide flat-bottomed hull, only slightly longer than the standard Curtiss pontoon, was attached under the lower wing of the de-engined airframe of the tractor seaplane with Type D wings and tailplane. A single 60hp engine was mounted in the hull and drove two tractor propellers through chains in Curtiss’s only deliberate adaptation of a Wright brothers’ feature. There were two side-by-side seats in a cockpit behind the wing. Although No.1 was unable to take off, the experiment did indicate that the flying-boat concept was practicable. Subsequent developments were made at Hammondsport.