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hull, which carried the tail members. To protect the crew, a wood and canvas superstructure had been built on the fore-part of the original pontoon, making its appearance very similar to that of the later Curtiss flying-boats. With experience this pontoon was extended further aft to carry the tail members, and so this flying-boat appears to have been progressively evolved.

In April 1913 a prize of 10,000 was offered by the Daily Mail for crossing the Atlantic in 72 hours, and Rodman Wanamaker had a two-engined (2x90 H.P.) Curtiss flying-boat, called the "America," made for this. Loaded to the necessary 5,000 Ib. gross, it could not leave the water. With a third engine it could do so, but the air endurance was thus reduced, and in July 1914 the flight was abandoned.

War Period. Up to July 1914 seaplane design was thus very backward, and its war usefulness to a fleet was but little indicated. The non-existence of any particular line of advance that could be systematically developed had adversely influenced its evolu- tion. In England in 1914 seaplanes were used in coast-defence work, and one seaplane carrier was in commission. By Aug. the carrying of aircraft on board ship had been facilitated by the introduction of folding wings, and their offensive value enhanced by the successful launching of a locomotive torpedo from the air. This led to the conversion of small passenger vessels into seaplane carriers, and soon the merits and limitations of the float type of seaplane were ascertained. As no launching- or landing-deck was available, the seaplane had to be operated from the sea, and this could be undertaken only in very favourable weather. An increase of air endurance and useful load was achieved, but at the expense of some of the seaworthy qualities. With a crew of two, wireless, and about 60 Ib. of bombs, an endurance of two to three hours at 70 knots was possible.

By 1915 an improvement of the same type (known as the "Short 184"), which survived throughout the war, could carry a heavier load for about five hours. They were intended mainly for duties with carrying ships, originally proposed for service with the fleet, and with the light cruiser and destroyer squadrons. As, however, these " float seaplanes " lacked sea-going qualities, and their carrier ships were vulnerable, many of the operations intended for them were abandoned. They were utilized in the Gallipoli campaign.

Air-cooled rotary engines, used on the seaplanes of 1914 be- cause they gave the lightest weight for power where weight was a cardinal consideration, soon proved unsuitable at sea, and were replaced by water-cooled engines. " Float seaplanes " were also employed with the Grand Fleet during the first two years of the war for observation with the. fleet at sea, and patrol, but they were handicapped because their sea-going qualities were not . adequate for the bad weather prevalent in the Ngrth Sea. At this time only one ship was provided with a forecastle deck large enough to enable a seaplane to be launched therefrom on a light subsidiary carriage, thus avoiding the necessity for stopping the ship with the attendant risk from submarines, when getting a seaplane into the air.

In the absence of seaplanes with good sea-going qualities, ordinary aeroplanes were carried in fighting-ships with a launch- ing-platform. Latterly carrier ships have been evolved with an alighting-deck as well. This led to the small seaplane not being pressed forward in the way the small aeroplane was by the stimu- lus of the war.

The " Boat Seaplane." In 1914 there was in the British serv- ice a small Sopwith boat seaplane fitted with wheels (winner of the Mortimer Singer trophy), and also two small French and American machines. They could not carry any appreciable load nor could their wings be folded for operation from carrier ships; accordingly they were not then developed. 'In July 1914 Lieut. Porte, who was engaged upon the twin-engined boat seaplane, the " America," previously mentioned, was instrumental in developing the modern " boat seaplane." In 1915 several " Americas " with their two go-H.P. engines were delivered at Felixstowe. Their performance was poor on account of their lack of horse-power for their weight; and they were too small 36 ft. hull to give good sea -going qualities.

The much larger " Porte " boats with their three engines of 275 H.P. and air endurance of 8 hours, a total weight of about 8 tons, and a hull 60 ft. long, were laid down. The increase of dimensions carried with it a great improvement in sea-going qualities, but the air performance was but little better, and the type was not further developed. One H.P. for 20 Ib. was in- sufficient power, and bigger engines for the weight had to be used.

The Curtiss " H8," built in America, was better in this respect. Only one of these was made, but knowledge obtained in England during its construction was embodied in its successor, the " Hi 2." Many Hi2 7 s, with 340-H.P. Rolls-Royce engines, were used with success against submarines. The Hi2's weighed 5 tons, carried 5 persons and 500 Ib. of bombs at 80 knots for 6 hours, and were armed with three or four machine-guns. They had i H.P. for every 16 Ib. and when first used had a higher performance than any other sea-going aircraft over the North Sea. They showed that hydroplaning efficiency, previously regarded as cardinal, could be sacrificed for sea-worthiness, provided sufficient engine- power were available.

All the earlier types, including the H8 and the Hi2's, were practically flat-bottomed, and pounded heavily in disturbed water; the higher power available in the latter type enabled these seaplanes to take off rapidly and the improvement of providing them with a pronounced V-section bottom was adopted first on a small " America, " and then on the H8 with the two Eagle engines.

This combination of Felixstowe hull, H8 wings with Rolls- Royce engines known as the F2 was the forerunner of all the many boat seaplanes of the latter part of the war. These craft, one of which is illustrated (see Plate II.), corresponded in size, weight and power to the Hi2 type, but on account of their V- section hulls, were capable of alighting in, and taking off from, disturbed water with less risk of damage to the hulls. Their effectiveness against submarines led the Germans to evolve high- performance two-seater fighter seaplanes of the float type. Among the most effective of these were the Brandenburg mono- plane seaplanes. These remarkable craft became useful as a menace to the heavier " boat seaplanes," and as they were carry- ing only a light machine-gun load and comparatively little fuel they out-manoeuvred them.

It has been seen that the small seaplane that might have count- ered these was undeveloped in England. The defensive arma- ment of the large seaplanes was increased, though such additional load adversely affected their performance and sea-going qualities. Small two-seater seaplanes to escort the larger ones were con- structed, but as these were not delivered until after the cessation of hostilities, the technical advantages to be derived from this new field of study were only partly reaped. Summarizing the above we see that the smaller boat seaplane originated in France, the large one in the United States of America, the very large one in England. Many seaplanes were brought to England from Amer- ica were improved by experience obtained in Britain, and sub- sequently the types designed at Felixstowe and built in England were reproduced in America in quantities.

The construction of the American " NC " type, and its cross- ing of the Atlantic, was a wonderful achievement. The fact that from lack of fuel " NC3 " alighted in mid-Atlantic, and arrived at Ponta Delgada after travelling 180 sea miles on the water in 54 hours with bad weather, pays a high tribute to the design and is a sign of the future value of the seaplane in com- mercial transport.

In France the war incentive to seaplane progress was lacking. France has mainly used the small boat seaplane for coast defence, and patrol for submarines. Up to the end of 1918 sufficiently high-powered engines were lacking for sea-going craft; the Hispano-Suiza 200-H.P. being in most general use.

In July 1914 the Germans had few seaplanes in service, and of these one had been imported from England. They were nearly all of the two-float type, and suffered from the defects of that type previously mentioned. Their activities were mainly de- fensive, and did not require either long endurance or good sea- worthiness. Torpedo-carrying seaplanes were made use of in