HMS Eagle was an early aircraft carrier of the Royal Navy. Ordered by Chile during the South American dreadnought race as the Almirante Cochrane, she was laid down before World War I. In early 1918 she was purchased by Britain for conversion to an aircraft carrier; this work was finished in 1924. Her completion was delayed by labour troubles and the possibility that she might be repurchased by Chile for reconversion into a battleship, as well as the need for comparative trials to determine the optimum layout for aircraft carriers. The ship was initially assigned to the Mediterranean Fleet and later to the China Station, spending very little time in home waters other than for periodic refits.
Eagle spent the first nine months of World War II in the Indian Ocean searching for German commerce raiders. During the early part of the war, the Fleet Air Arm was desperately short of fighters and Eagle was equipped solely with Fairey Swordfish torpedo bombers until late 1940. She was transferred to the Mediterranean in May 1940, where she escorted convoys to Malta and Greece and attacked Italian shipping, naval units and bases in the Eastern Mediterranean. The ship also participated in the Battle of Calabria in July but her aircraft failed to score any hits when they attempted to torpedo Italian cruisers during the battle. Whenever Eagle was not at sea, her aircraft were disembarked and used ashore.
The ship was relieved by a more modern carrier in March 1941 and ordered to hunt for Axis shipping in the Indian Ocean and the South Atlantic. Her aircraft sank a German blockade runner and disabled a German oil tanker in mid-1941 but did not find any other Axis ships before the ship was ordered home for a refit in October. After completing an extensive refit in early 1942, the ship made trips delivering fighter aircraft to Malta to boost its air defences in the first half of 1942. The torpedoed and sank Eagle on 11 August 1942 with 131 lives lost as the ship was escorting a convoy to Malta during Operation Pedestal.
Design and description Construction and conversion
In 1911, the Chilean Navy ordered one super-dreadnought battleship, with an option for a second ship, each to be armed with ten 14-inch (356 mm) and sixteen six-inch (152 mm) guns, that were named and Almirante Cochrane.Brook, p. 146 Almirante Latorre was laid down in December 1911, followed by Almirante Cochrane at the Armstrong yards at Newcastle upon Tyne on 20 February 1913. On the outbreak of the First World War, construction of the two ships was suspended. The British Admiralty purchased the almost-complete Almirante Latorre, which then in 1915 entered service as . At the outbreak of war, Almirante Cochrane was almost complete up to the forecastle, although her side armour had not yet been installed. No further work was carried out during the war until the British decided to complete her as an aircraft carrier for the Royal Navy. They purchased her from Chile on 28 February 1918 to be converted into the carrier HMS Eagle.Gardiner and Gray, pp. 38, 70 She was the fourteenth ship of the Royal Navy to bear that name.Colledge and Warlow, p. 108
The Director of Naval Construction began preliminary design work even before the ship was purchased and submitted an outline design on 8 February 1918. This design had a full-length flight deck. Its most distinctive features were the two islands separated by the flight deck. Each island was to be long, containing two funnels and a tripod mast. They were staggered to make it more difficult for an enemy ship to estimate the ship's course and were to be connected to each other with heavy bracing. The bridge was to be mounted on top of this bracing which left a clear height of for the aircraft on the flight deck. There was to be a wide space between the islands where the aircraft were to be assembled before taking off. Aircraft would be transported between the hangar and the flight deck by two aircraft lifts (elevators). A crane was to be located at the aft end of each island to lift aircraft aboard and to recover seaplanes. Bulk petrol storage consisted of in tins stowed on the forecastle deck and protected by plating. Two ready-use tanks near the islands would allow aircraft on the flight deck to refuel. The ship's planned armament consisted of nine 6-inch guns and four anti-aircraft guns mounted on the platform between the islands.Friedman, pp. 74–75 Eagle retained the battleship's mixture of coal and fuel oil, but the quantities were increased to of coal and of oil, as the forward and rear 14-inch magazines and shell rooms were converted to be used as oil tanks.
Based on trials with , in which pilots were found generally to turn to port when recovering from an aborted landing, the design was revised to eliminate the port island in April 1918. The starboard island was lengthened to and its width was reduced to to minimise air turbulence. The island contained the bridge, both funnels, and the tripod mast that carried the fire-control directors for the armament. At the request of Admiral David Beatty, commander of the Grand Fleet, the main armament was increased to 12 six-inch guns, including one mounted on the island, and eighteen torpedo tubes were added, three triple fixed mounts on each broadside, in case the ship met German light cruisers at night. The anti-aircraft armament was reduced to a single 4-inch gun mounted on the island between the funnels as Beatty believed that the ship's own fighters would be her best defence against enemy aircraft. This design was approved in June, although work had begun earlier.Friedman, pp. 74–76
The armour planned for her upper belt was used to protect the ship's waterline. The already-completed superstructure was removed as were the barbettes for the 14-inch guns.Friedman, p. 75 Eagle was launched on 8 June 1918 and was towed downriver to the shipbuilder's High Walker yard for fitting-out ten days later. The boiler uptakes were re-routed and the existing openings were plated over. The existing upper deck became the floor of the hangar deck and a new superstructure was built above it. The flight deck was thick and served as the uppermost strength deck, or main supporting deck, of the ship. When the war ended in November 1918, the ship was about nine months from completion.Brown, p. 250
Construction was slowed by industrial action after the war, and was suspended on 21 October 1919 as Chile wanted to repurchase the ship and have it re-converted to a battleship.Friedman, p. 79 The £2.5 million cost of doing so would have been higher than the £1.5 million offered by the Chileans and the Admiralty decided to retain the ship. The Royal Navy needed to carry out flying trials with a carrier fitted with an island, and the Admiralty approved the use of Eagle on 11 November. Armstrong Whitworth plated over the openings for the undelivered lifts on the flight deck that had been cancelled when they could not meet the specifications. Armstrong Whitworth also finished the rear funnel, removed the torpedo tubes, and plated over the forward funnel uptakes. She then sailed to the Royal dockyard at Portsmouth for the modifications necessary for the trials on 20 April 1920.Brown, pp. 250–251 Only two of her boilers, converted to run on fuel oil only, could be used during the trials.Brown, p. 251
Flight trials
The trials principally tested the longitudinal arresting gear used previously on the small aircraft carrier .Brown, p. 252 They were not intended to stop landing aircraft—the landing speeds of the time were low enough that this was unnecessary given a good headwind—but rather to prevent aircraft from veering off to one side and falling off the flight deck.Friedman, p. 95 Initially, the arresting gear was about long and was installed too far forward. Over the course of the trials it was moved further to the rear and lengthened to a total of .Friedman, pp. 79–81
The ship was commanded during the trials by Captain Wilmot Nicholson, who had previously commanded the carrier in 1918, and the Royal Air Force representative was Group Captain Charles Samson. Taxiing trials began on 10 May with Sopwith Camel fighters and Parnall Panther reconnaissance aircraft while the ship was still docked. Flights over and around the ship to evaluate air currents over the flight deck and around the island began shortly afterward and the first on-board landing was made on 1 June. Larger aircraft like the Bristol F2B fighter, the Sopwith Cuckoo torpedo bomber, and the De Havilland DH.9 bomber were also evaluated during the trials. They were generally successful with only 12 minor accidents in 143 landings in all types of weather conditions, although they did reveal that aircraft landing aboard carriers would need landing gear fitted with shock absorbers to handle the impact of landing on a pitching deck.Friedman, pp. 81–82 Group Captain Samson strongly preferred the elimination of the island entirely, but Nicholson recommended that the ship be retained for service, although he was not satisfied with the size and shape of the island. He also recommended that Eagle be converted to burn fuel oil exclusively and that the removal of the 6-inch guns in exchange for anti-aircraft guns would allow the tripod mast in the island to be eliminated, since it would not then be required for fire control purposes .Friedman, p. 82
Description The ship was paid off on 16 November, but did not begin construction to a revised design until 24 March 1921 at Portsmouth. The Admiralty accepted some of Nicholson's suggestions, but not all. The shape and size of the island was modified in accordance with the results from wind tunnel testing at the National Physical Laboratory, but the 6-inch guns were retained. The forward edge of the flight deck was faired into the ship's bow to smooth out the air currents over the bow and the 4-inch anti-aircraft guns were mounted on and around the island. The forward lift was moved to the forward end of the hangar. After construction began, anti-torpedo bulges were added, deep, and the petrol tin storage room was replaced by a tank. The ship's designed fuel capacity was , but this was increased to when she was bulged. However, of this amount was required to act as ballast to offset the weight of the island and its equipment.Brown, pp. 252–253
Eagle had an overall length of , a beam of , and a draught of at deep load. She displaced at standard load. Each of the ship's four sets of Brown-Curtis geared steam turbines drove one 3-bladed propeller.Brown, p. 272 They were powered by 32 Yarrow small-tube boilers. During her sea trials on 9–10 September 1923, the turbines produced and gave Eagle a speed of , but this caused leaks in the turbine joints and she was limited to a maximum of in service. She had a range of at .Friedman, pp. 82–83, 366
The ship's flight deck was long and her hangar was long and wide. Its minimum height was , and it was equipped with four steel shutter fire curtains to isolate any fires in the hangar. The forward lift's dimensions were and the aft lift was . The fore-and-aft arresting gear was long and extended the length of the flight deck between the edges of the lifts.Brown, pp. 253–254, 273 A large crane with a radius was positioned behind the island. The ship's aircraft capacity was 25 to 30 and, in 1939, the ship's crew totalled 41 officers and 750 men, exclusive of the air group.Friedman, p. 83, 366
For self-defence against enemy warships, Eagle had nine BL Mk XVII 6-inch guns, three at the stern and six along both sides of the ship. The ship carried 200 rounds per gun. Two of her five QF Mk V 4-inch AA guns were positioned on the flight deck in front of the island while a third was behind the island. The remaining two guns were mounted on top of the island, one between the two funnels, and each gun was provided with 150 rounds.
Career
Inter-war