AIRCRAFT CARRIER. The advent of the aeroplane has provided navies with a new means of reconnoitring for an enemy; of observing his movements; and correcting gunfire. In fact, aircraft have joined the .cruiser of to-day, the frigate of old, as the "eyes" of the fleet. Moreover, they have extended the vision of an individual ship from that due to the height of her mast head to one limited only by the range of an air observer who can maintain wireless communication. In addition they have provided a new method of attacking naval objectives by means of bombs and by torpedoes launched from the air.
To be of practical value to a fleet at sea, however, it is necessary that naval aircraft should be available whenever their services may be required, and weather and other conditions permit of their being used. Owing to their limited fuel endurance and inequality of speed with ships, it is impracticable for aircraft to fly continu ally with the fleet. Flying-boats, capable of moving on the sur face, have not yet been sufficiently developed to withstand the buffeting of what, for ships, would be very moderate seas. They can, therefore, only operate with a fleet which is within easy range of a sheltered base.
The alternative to summoning aircraft from a shore base is to carry aircraft with the fleet and launch them into the air as and when required. Owing to the innumerable obstructions on the up per deck of a warship, it is very difficult even to find stowage room for more than one or two aircraft, and quite impossible to provide the necessary space for them to alight on the deck; but in some of the latest ships in modern navies arrangements are now fitted for aircraft to be projected into the air by a species of catapult. All of the battleships and new cruisers of the United States Navy carry aircraft, and many of them are fitted with catapults. In order to provide the necessary number of aircraft which a fleet will require in the future, and a suitable ship for them to return to when they have completed their flight, the aircraft car rier has been designed. This type of vessel combines a roomy hangar with a clear, flush deck, free from obstructions, for taking off and alighting. At the same time it has introduced a new prob lem in fleet tactics ; for the aircraft carrier can only work her air craft by steaming into or directly away from, the wind, which may result in her becoming detached from the main fleet during an engagement. This, and the fact that, by the nature of her con struction, she is very vulnerable and a large target, means that she is a comparatively easy prey to a force of enemy cruisers. In other words, aircraft, carried in carriers, will operate in a fleet ac tion with the handicap that their mobile base is not a very secure resting place either for their departure or return. This, and the limitations imposed on them by bad weather, fog and darkness, preclude their becoming a complete substitute for cruisers and des troyers, for, clearly, the fleet cannot be dependent on intermittent scouting, and it may often be under just such conditions as pre vent aircraft operating that information concerning the enemy, and a means of countering his own light craft, are most important. In other words, aircraft and their carriers have become indispen sable auxiliaries to navies, but they cannot replace the older types of warships. (E. A.) Types of Aircraft Carriers.—Between 191 o and the beginning of the World War, trial flights had been made from warships in the U.S. and British Navies, but the progress made was slow, and it was not until just prior to the outbreak of war in 1914 that a vessel was taken in hand for conversion to an aircraft carrier. The British Government then took over a tramp steamer, renamed the "Ark Royal," and fitted her with a flying-off deck forward and two cranes for lifting the seaplane inboard after returning from a flight. In the summer of 1917 the first landing was made upon a British warship while under way.
Further carriers being needed, several passenger vessels were taken over and converted into seaplane carriers. The largest of these, the "Campania," was taken up in 1915, and a large flying-off deck fitted forward for the purpose of flying seaplanes off wheel trollies. These alterations were completed early in 1916, and proved fairly successful. A demand arose for further carriers to accompany the British fleet at sea. Amongst the smaller vessels adapted as carriers were the "Riviera" and "Engadine," the lat ter being the only carrier present at the battle of Jutland. Later the "Pegasus" and "Nariana" were similarly equipped: The next vessel taken over was the Italian passenger and cargo ship "Conte Rosso," renamed "Argus," which in 1916 was build ing at Beardmore's. A complete flying deck was fitted fore and aft with a hangar for stowing the machines under this deck. The funnels were made to run horizontally beneath the flying deck to the stern, so as to discharge all funnel gases abaft the stern with the aid of fans. For transporting purposes lifts were fitted from the hangar to the flying deck, and cranes to lift the machines from the water. To enable machines to be carried on the deck in addi tion, wind-breaking palisades were fitted which could be raised simultaneously above the level of The flying deck. The "Argus" was the first ship to prove a really satisfactory carrier on which aeroplanes could alight and fly off with safety. Workshops were fitted on board and the vessel was, in fact, a floating aerodrome which could accompany the fleet in all circumstances.
Whilst the first trials of this vessel were proceeding, early in 1917, it was decided to appropriate the "Furious," then completing at Messrs. Armstrong's naval yard, for aircraft-carrying purposes. This ship was originally designed as a large light cruiser to carry two i8in. guns in single turrets, one forward and one aft. The first stage of conversion was to remove the forward turret and fit a flying-off deck and hangar, and from this deck seaplanes and aero planes could be flown off successfully. Later, the stern i8in. gun was removed, and a big flying-on deck fitted, the two flying decks forward and aft being joined by a walking way around the mast and funnel. Owing w disturbances set up by funnel gases and eddies around the funnel structure, this flying-on deck was not a great success, and the ship was further reconstructed, being finally completed in 1925. This vessel was fitted, like the "Argus," with a clear fore and aft flying deck, the funnel gases being led out over the stern. She has two very large hangars, one above the other, and has a deck forward from which aircraft may fly off, in addi tion to the main flying off and alighting deck; this was an entirely new and important feature which is being copied in later aircraft carriers.
About the same time as the appropriation of the "Furious" for conversion, designs were prepared for a carrier named the "Hermes," and this was the first vessel primarily designed as an aircraft carrier. Some six months after, the Chilean battleship "Almirante Cochrane," building at Messrs. Armstrong's works, was taken over for conversion and renamed the "Eagle." The "Island" Type.—Inboth these vessels a departure was made in the construction of the flying deck, since a completely clear fore and aft deck was not fitted, as in the "Argus" and "Furious." The funnels and navigating positions were incor porated in an "island" arranged on the starboard side, thus giving a clear deck of a width only slightly less abreast the island than just forward or aft of it. This feature is shown in Pl. I., figs. Following on the satisfactory results obtained with the "Furi ous," it was decided, in 1926, to convert the two larger light cruisers "Courageous" and "Glorious" into aircraft carriers. In these two ships a reversion is made to the island type, as in "Eagle" and "Hermes," and the clear deck, as in "Furious" and "Argus," is not repeated. The island type has also been adopted in the U.S., French and Japanese navies, but it is still doubtful which type will eventually prevail.
This question of the choice between the clear deck, with no obstruction at all, and the alternative of the island type—that is, with the navigating position and bridge, with all instruments such as range finders, fire control, etc., and the mast, funnel and per haps some guns, all being located in a small, very narrow space on one side of the deck, as shown in the photos of "Hermes" and "Eagle"—is a much disputed one. The clear deck has the advan tage of presenting no obstruction whatever to the aeroplane pilot as he approaches the ship with the intention of alighting on deck. The island type, whilst providing a much better navigation and control position on an elevated bridge, presents a serious obstruc tion on one side of the ship, and the pilot, in alighting on board, must so steer that, whilst one wing is in no danger of touching, the other is clear of the island standing up on that side of the deck. Some pilots, however, prefer the island, which gives them a good indication of the exact height they are above the deck when about to alight, it being more difficult to estimate this height with accuracy in the case of the clear deck. The stern view photograph of H.M.S. "Eagle" indicates very well the kind of view of the ship which is presented to the pilot when approaching to alight on board; it shows the deck curved downwards towards the stern to help him, in case the ship is rising and falling in the swell of the sea, and it also shows a good view of the island on the starboard side.