round-downs that overhung at both bow and stern. The after round-down was particularly pronounced, being designed to an aerodynamic shape to smooth the airflow on the final approach and completely overhanging the water aft of the stern. The round-downs meant that, although the flight deck was 800ft long between perpendiculars, only 720ft of it was level and therefore useable for ranging, launching and recovering aircraft. In order to carry as many aircraft as possible, the double hangar arrangement was retained.
Armour protection was not provided for the flight deck or hangars, but the lower hull was armoured to contemporary cruiser standards. The lower hangar deck was constructed of 3.5in armour plate which extended outboard to meet the top of the 4.5in waterline armoured belt. The end bulkheads were 3in, creating an armoured ‘box’ over machinery, magazines and steering gear. An improved form of bulge and an internal splinter-proof bulkhead were believed to be proof against a 750lb torpedo warhead or contact mine. The island housed the navigating bridge, flying control arrangements and the funnel. Since the gun armament was intended for anti-aircraft fire there was no requirement for a spotting top to control surface fire like those in Eagle and Hermes, and none was fitted.
Two BH 3 hydraulic catapults, each capable of launching 12,000lb at 56 knots, were fitted, one either side of the flight deck forward. Four arrester units were installed in the ‘deep beams’ between support girders under the flight deck aft, each of which had two arrester wires rove to it, capable of stopping an 11,000lb aircraft at a speed relative to the deck of 55 knots with an average pull-out of 140ft. Both the relative entry speed and pull-out varied between wires, decreasing for the wires nearest the barrier. For the first time in a British aircraft carrier, a fifth unit was installed which controlled the safety barrier; this had the same entry limitations as the wires but a pull-out of only 40ft. The safety barrier was an American idea introduced by Captain Joseph Reeves USN, the first captain of the USS Langley. Noting that it took time to range aircraft from the hangar, he wanted aircraft kept on deck, where they could be refuelled and rearmed quickly between sorties. He wanted a safe parking area, and achieved this by having a barrier of steel wire rope constructed across the flight deck amidships, supported on either side of the deck by collapsible metal stanchions. When raised it prevented aircraft that missed all the arrester wires from rolling forward into the new deck park. In use it was manned by an operator in the port catwalk. As soon as he saw that the next aircraft to land had caught a wire he would lower the barrier, allowing the aircraft to taxi forward safely into the parking area forward, known to aircraft handlers as ‘Fly One’. As soon as the aircraft had passed over the barrier it was raised again to allow the next aircraft to land on.
Ark Royal as completed in 1938. (AUTHOR’S COLLECTION)
Ark Royal anchored at Spithead in June 1939. The two port multiple ‘pompom’ mountings have not yet been fitted. (AUTHOR’S COLLECTION)
The first aircraft airborne from Ark Royal out of a mixed range of aircraft during flying trials. (AUTHOR’S COLLECTION)
With the introduction of the barrier in the USN, and the new techniques it allowed, aircraft in the landing circuit could back each other up more closely, reducing the landing interval between aircraft from about four minutes to less than one. The RN had wanted to introduce barriers as soon as the advantages became obvious, but the RAF had opposed the idea because of the possibility of aircraft being damaged. Once the Inskip Award allocated the control of carrierborne aviation back to the navy, where it rightly belonged, the RN could insist on the equipment it needed for the most efficient operation of aircraft, and Ark Royal was designed to have a single barrier. By the time she was launched, similar devices had been in service with the USN for a decade. The new landing technique was further improved by the adoption of Deck Landing Control Officers (DLCO), known colloquially as ‘batsmen’, who took charge of the landing by signalling to pilots whether they were high, low, left or right and ordering them to cut the throttle when ideally placed for the hook to catch a wire. The landing was the DLCO’s responsibility and, while there was some resistance from ‘old hands’ at first, the new system dramatically reduced the number of landing accidents, speeded up the whole process and was soon accepted as the best way forward.
The advantage of the double-hangar arrangement was that a large number of aircraft could be stowed in a ship with a relatively small displacement. In 1935, when Ark Royal was laid down, this seemed a good idea because aircraft were expected to operate around the clock, launched in small numbers at any one time to search for an enemy fleet and to carry out small-scale torpedo attacks to slow an enemy force that sought to evade a surface action. By then the speed demonstrated by new monoplane bombers meant that the Admiralty was forced, reluctantly, to conclude that carrierborne fighters no longer represented the best way of defending the fleet against enemy air attack, since the time between visual sighting of enemy aircraft and bomb release would be too short to launch
intercepting fighters with any chance of breaking up the attack. Fighters could, of course, be kept airborne on combat air patrol (CAP), but would be needed in impossibly large numbers flying all round the fleet to be effective. For this reason guns were deemed to offer the best defence, and the only fighters available when Ark Royal commissioned were the dual-purpose fighter/dive-bomber Blackburn Skuas intended to escort Swordfish strikes and attack ships in their own right with 500lb bombs. A solution to the fleet air defence problem emerged in the first days of the war, however, when radar proved capable of detecting enemy aircraft at long range and directing fighters accurately to intercept them. Now a reasonable number of embarked fighters could be maintained on CAP during daylight hours with every chance of a successful interception. Unfortunately the discovery came after the heavily armoured carriers of the Illustrious class that followed Ark Royal had been designed, and it took some time to procure adequate high-performance fighters. Ark Royal herself was never fitted with radar, but evolved a successful technique of using the air warning radars of cruisers in company to direct her aircraft throughout 1940 and 1941. Had she survived, this shortcoming would have been addressed in a major refit during 1942.
Ark Royal alongside in Portsmouth early in the Second World War. The censor has made a halfhearted attempt to blank out the Type 72 aircraft homing beacon, but this photograph gives a good view of the structure that supported the two catapults. The recently fitted external degaussing coil also shows up well. (AUTHOR’S COLLECTION)
Ark Royal’s two hangars had a total deck area of 52,580ft2, the largest yet achieved in a British carrier. Her original specification envisaged an air group of seventy-two aircraft, all to be stowed in the hangars, but the RAF objected that ‘such a large number could not be operated safely’.
Reluctantly, the Admiralty accepted that, while the larger number of aircraft could physically be struck down into the hangars, the ship would be completed with workshop capacity, spare part stowage, magazine space and ‘hotel accommodation’ based on support for an air group of only sixty aircraft, and in her short life this was never altered. She never used a deck park to add to the number of embarked aircraft.
Avgas capacity was 100,000gal, stowed in non-integral cylindrical tanks like those used in the Courageous class. Some changes were made as a further precaution against leakage and fire, and instead of the water-displacement system used since 1923 an air-pressure delivery system was used to avoid contamination of the fuel by salt water. As a further precaution CAFO 257/37 called for the compartments containing the avgas tanks to be flooded when action was imminent. To avoid corrosion, the inside of the compartments and the outside of the tanks were to be coated with one coat
of bitumastic solution and one coat of enamel, all existing paint to be removed and the metal surfaces thoroughly cleaned before their application.
For the first and only time the RN opted to have three lifts within the flight-deck perimeter. To maintain the flight deck’s integrity as a strength deck the apertures were made as small as possible, with two offset to starboard and one to port of the centreline. This preserved the girder strength, but meant that only folded or partly dismantled aircraft could be struck down or ranged, unlike the cruciform lifts in previous British aircraft carriers. The lifts were grouped in the forward part of the hangars, making it difficult to extract aircraft from the after sections of both hangars, and only folded aircraft could be manoeuvred around the lift wells. The lifts themselves were unconventional in that each platform served only one deck. To get an aircraft from the lower hangar to the flight deck involved a handling party pushing it on to the lower platform, raising it to the upper hangar, pushing it clear, and lowering the platform to the lower hangar deck level. The upper platform could then be lowered to the upper hangar deck level, the aircraft pushed on, raised to the flight deck and pushed clear into the range. This cumbersome arrangement stemmed from the early concept that the lower hangar would be used for deep maintenance, and serviceable aircraft would be kept in the upper hangar. Wartime carrier operations required large numbers of operational aircraft to be ranged quickly from both hangars, and this cumbersome lift arrangement was never repeated.
In the mid-1930s carriers were expected to operate ‘in support’ of the battle fleet but not ‘the battle line’. The need for frequent turns into wind to launch and recover aircraft might take the carrier and its screening destroyers away from the main fleet, so high speed was considered essential for the carrier to resume station. The need to generate wind over the flight deck for flying operations was not considered important at the time, but became so as embarked aircraft weights increased dramatically after 1940. Ark Royal was specified to be capable of 31 knots, 3 knots faster than the projected King George V class battleships and considerably in excess of their predecessors. The power to develop this speed could not be achieved by a two-shaft installation, and a four-shaft installation would have led to an unacceptable increase in standard displacement and required considerable extra manpower.
Therefore a three-shaft arrangement was adopted; this was unusual for the RN but had been used by the German Navy for a number of capital ships before 1918. The machinery developed 103,000shp, which developed 31.75 knots on trials with a clean hull. The original design called for four steam- driven turbogenerators and two diesel generators, but the latter were subsequently replaced during construction by two further steam generators to give added capacity for the full action load.
Unfortunately this meant that electrical power in the ship depended entirely on steam being available from the boilers.
The overhang aft was the largest structure of its kind fitted to a B ritish aircraft carrier, but aircraft could not be ranged on it or land on it because the of the slope of the round-down. It was a purely aerodynamic shape to smooth airflow over the after part of the deck. (AUTHOR’S COLLECTION)
In the years immediately before the introduction of practical air-warning radar in ships, Ark Royal’s primary defence against air attack was thought to be provided by guns. Eight twin 4.5in guns were disposed in pairs in four batteries near the ‘corners’ of the ship. They were mounted high on sponsons so that they could fire at low angles across the flight deck at targets on the opposite side of the ship. In practice this theoretical benefit was outweighed by the blast damage suffered by aircraft, flight deck and catwalk fittings, so it was seldom used in action. Each battery was controlled by a single director mounted on the deck edge near the guns. Each director could control the fire of its own battery; the two batteries on its side of the ship or all batteries if required. They were never fitted with gun-direction radar, and relied on optical range-finding to control time-mechanical fused shells in barrage fire. Six eight-barrelled 2pdr ‘pom-poms’ were fitted, two forward of the island on the flight deck; one on the after end of the island; one on the flight deck aft of the island and two on a sponson at the port deck edge amidships. The latter were not fitted during initial flying trials in case they interfered with flying operations.
Ark Royal was never fitted with radar but she did have a Type 72 aircraft homing beacon. Had she not been lost she was programmed to carry out a major refit in the USA in early 1942 which would have seen considerable enhancements to her operational capability.
Ark Royal’s loss
She was hit at 1541 on 13 November 1941 by a single torpedo fired by U-81 thirty miles east of Gibraltar while the ship was steaming at 22 knots, returning from a sortie with Force H to ferry RAF fighters to Malta. Some of the blast vented up the bomb lift forward of the island, and the ship was felt to whip violently. Witnesses in the battleship Malaya 400 yards away saw the ship whip so severely that aircraft on deck were thrown into the air and bounced several times as they fell back into the deck (indicating that they had not been lashed to the deck after a recent recovery). The area of maximum damage appeared to be between the keel and the starboard side abreast the island structure, and subsequent analysis calculated that a hole approximately 130ft by 30ft had been blown in the bottom plating, indicating a failure of the internal anti-torpedo structure. The hole was larger than expected from a single hit, but it had taken some time for the ship to stop and her initial speed may
have made the hole bigger.
After the explosion the starboard boiler room, air spaces, oil tanks and watertight compartments on the starboard side began to flood, together with the main switchboard room and the lower steering position. The port and centreline boilers continued to steam, but the centreline began to flood slowly from below. The engine rooms had lost communications, which is why it took so long to stop the ship, and she immediately heeled 10 degrees to starboard, increasing to 18 degrees after 20min. The flooding of the main switchboard room and telephone exchange caused the failure of all lighting, electrical power and telephones, making the situation appear worse than it actually was, and the captain decided, half an hour after the explosion, to bring destroyers alongside to evacuate the ship, leaving the generators in the port and centre boiler rooms running. At about 1600 the destroyer Legion came alongside Ark Royal’s port quarter and took off over 1,000 men, casting off at 1648, by which time the captain had ordered damage control parties to save the ship. Unfortunately, however, a number of key men had already been taken off. Counter-flooding reduced the heel to 14 degrees.
Electric power, feed water and pumps were supplied by Laforey for a time, but she slipped at 2224 when it appeared that Ark Royal had her own steam and power once more and that flooding was under control following the valiant efforts of a repair party of sailors from Hermione and Legion led by Ark Royal’s Gunner (T).
The ship was taken in tow at 2 knots by the tug Thames, with steam raised in the port boiler and lighting restored, but the starboard engine room continued to flood slowly, increasing the heel again to 17 degrees and flooding the boiler uptakes at the point on the starboard side where they were taken vertically up to the funnel. With nowhere for the exhaust gas from the port boilers to go, fire broke out in the air casing and this led to the evacuation of the boiler room and a total loss of power again. The Senior Engineer and two of his men collapsed while attempting to keep the boilers working and had to be given artificial respiration. Viewed in hindsight, it is difficult to see why Laforey was not kept alongside to guarantee a power supply, given the importance of keeping the carrier afloat, but she was brought alongside again after power was lost for the second time. By then it was too late. The heel increased to 27 degrees at 0400 on 14 November, at which point the order was given to abandon ship, and everyone was taken off by 0430 except one man who had been in the main switchboard room during the initial impact. Twelve hours after the torpedo impact, all personnel had left the ship and the heel had increased to 35 degrees. She capsized and sank, after ‘hanging’ for a few minutes at 45 degrees, two hours later. The last 250 men to leave crossed over the tug St Day to Laforey.
Ark Royal and Argus head towards Gibraltar after ferrying RAF aircraft to M alta in November 1941. They are seen from Malaya. (AUTHOR’S COLLECTION)
Ark Royal about a minute after being hit by a torpedo from U-81. She is still under way but is already listing to starboard.
(AUTHOR’S COLLECTION)
The key vulnerability was the position of the boiler uptake trunking, but the steady spread of flooding into the centre and then port boiler rooms through the fan trunking was also a factor. The lack of diesel generators to provide electrical power was also a critical shortcoming. The early evacuation and the number of manhole covers and armoured doors left open by men leaving the ship led to an increased rate of flooding which lowered the hull in the water and immersed the funnel uptake trunking earlier than would otherwise have been the case. The subsequent Board of Enquiry noted that the size of the hole and the initial flooding it caused led to a list well beyond that envisaged in the ship’s damage control books, which provided counter-flooding instructions for lists of only up to 8 degrees. Subsequent analysis showed that if the port engine and boiler rooms had been flooded after steam power had finally failed, Ark Royal could have been brought to an even keel, retaining enough buoyancy to reach harbour. The Board further noted that it considered it to be essential that the training and organisation of damage control personnel should, in future, be of the highest standard in order to deal satisfactorily with an emergency of this type. Counter-flooding should be carried out quickly to correct a list in excess of 6 degrees. Changes in carrier design could not be carried out overnight, but the Board recommended that, as soon as possible, boiler uptakes and fan intakes should be carried higher where practical, and machinery should be run in units irrespective of the number of boilers alight. The positions of the main switchboard and telephone exchange should be reviewed to render them less liable to flooding, and control of the electrical ring main must be reviewed to avoid false operation in the event of flooding or wiring damage. Diesel generators must be fitted in all large ships. Lastly they stressed the need to have direct communication at all times between the bridge and engine rooms with alternative power supplies including sound-powered telephones.