5
Although by 1950 the US Navy was clearly the world’s most powerful navy with a carrier fleet to match, the Royal Navy was making up for its smaller size by pioneering a series of vital inventions that were to prove the key to operating the new generation of high-performance jets then under development. However, being a pioneer in any field is never easy and many ideas were tried and tested before a concept could be brought to the stage where it could be safely applied to everyday carrier operations. Inevitably, some of these ideas led to a blind alley, but not before a considerable amount of time and effort had been expended, and in this category is firmly placed the concept of the flexible deck.
This had its origins as far back as 1944/5 when the first jet fighters were entering service. It was immediately apparent that they lacked the range of their piston engine contemporaries due to the high fuel consumption of jet engines. One idea put forward was that if the undercarriage could be dispensed with then the saving in weight and space could be utilised to substantially increase fuel tankage. The idea was not quite as bizarre as it might appear as several advanced German aircraft such as the Me.163 rocket-powered interceptor and early versions of the Arado Ar.234 jet bomber had used this method of operation. The main drawback was obviously the necessity to lift the aircraft onto some form of cradle after landing before it could be moved. For this reason the RAF quickly abandoned the idea but the Royal Navy was more interested as it saw it as one way of redressing the weight penalty inherent in naval aircraft necessitated by the need for extra equipment and strengthening for deck operations. Also, as naval aircraft were routinely launched from catapults, this method could easily be applied to undercarriage-less aircraft mounted on a suitable trolley. Major Green, one of the engineers working at RAE Farnborough, put forward a scheme whereby a landing aircraft could engage an arrester wire and be brought to rest on a large rubber mat suspended above a carrier’s flight deck. After a successful landing, the aircraft would be winched to the forward end of the mat where it would be pulled onto a specially designed trolley. It could theneasily be moved around the deck and the same trolley could be attached to a catapult for take-off. It was estimated that a landing rate of one aircraft every thirty seconds could be achieved.
Further development now became the responsibility of the Naval Aircraft Department at Farnborough who refined the design to include a series of inflated canvas tubes to provide an air bed under the rubber mat in order to absorb and cushion the impact of the landing aircraft. By 1946 an experimental bed had been set up at Farnborough and a series of experiments was carried out in which surplus Hotspur glider fuselages loaded with various amounts of ballast were dropped onto the bed. It was found that the best results were obtained with a combination of the inflated tubes laid out under a tensioned rubber mat. (In the typical make-do fashion of many British projects, the inflatable tubes were actually made from surplus fire hoses!) Further tests were then made with unmanned complete Hotspur airframes, which were rocket launched so that they engaged the arrester wire almost as soon as they achieved flight. In order for a manned aircraft to make a successful engagement, it would be necessary for the pilot to approach the deck and its single arrester wire (suspended some three feet above the deck) at a fairly flat angle and at a speed that would not impart too much energy to the system on landing. Also, it would be necessary to judge height over the deck very accurately - typically a height of five feet was required. A series of tests was therefore flown by the famous naval test pilot Cdr Eric Brown RN who had already made the first successful carrier jet landing in December 1945, using an Aircobra and then a Hellcat. These tests consisted of flying typical approach profiles and then coming over the deck, although no attempt was made to engage the arrester wire, which was not rigged. It was quickly apparent that such flying techniques presented no particular problems as was confirmed when similar trials were flown by a representative selection of other pilots.
All was now ready for the first actual landing on the rubber deck, which was installed on the airfield at Farnborough alongside one of the runways. The mat was 200 feet long and 60 feet wide, with steel ramps at either end and an arrester wire suspended 30 inches above the landing end of the deck. The aircraft selected was the second prototype Sea Vampire F.20 and for the trial it retained its normal undercarriage, although, of course, this was left retracted. On 29 December 1947 Cdr Brown made the first attempt at a rubber deck landing in a piloted jet aircraft. Unfortunately this attempt was not a resounding success as wind eddies on the final approach caused the aircraft to sink too low and, as the pilot attempted to pull up, the tail booms and arrester hook hit the lead-in steel ramp causing the aircraft to pitch forward and the arrester hook to lock in the UP position. Consequently the wire was not engaged and the aircraft pitched nose down into the deck, bounced up, hit the steel ramp at the upwind end and finally skidded to a halt on the grass area beyond, having incurred substantial damage to the nose and cockpit area. Fortunately Cdr Brown was unhurt and after some modifications to a second Sea Vampire and to the method of approaching the deck, a successful landing was made on 17 March 1948. By November of that year a total of thirty-three successful landings had been completed and only a few minor, easily rectified, problems had been experienced.
In the light of the promise of the early trials, authorisation was given for seagoing trials to be carried out aboard the light fleet carrier HMS Warrior. The carrier was fitted with a 300-foot rubber deck during the middle part of 1948 and this work was completed in time for trials to commence at the beginning of November. The installation was placed on the after end of Warrior’s flight deck, leaving the forward 300 feet free for take-off and parking. The first successful landing was made on 3 November and subsequently over 150 deck landings were made, almost totally without incident and by a wide cross-section of both Royal Navy and RAF pilots as well as one US Navy pilot. The aircraft used in all these landings except the first were standard Sea Vampire F.21s, which were capable of being catapult launched. (The first landing used an F.20, which could not be catapulted and required a 42-knot wind over the deck before it could be flown off from the forward portion of the ship’s flight deck.) In all, 271 landings were made using both shore-based and shipboard installations and the fact that there were no accidents clearly illustrated that the system worked. Unfortunately, aircraft developments had to some extent overshadowed the original idea behind the concept and its widespread adoption would require a substantial investment in deck facilities both aboard ship and at shore bases, and the necessary finance was just not available.
As a postscript, the idea was revived in early 1950 and a 400-foot deck was erected at Farnborough. Trials again utilised Sea Vampires but the prototype Sea Hawk made two successful landings in 1953 and in all some 304 landings were made between 1952 and 1955. The impetus for these new trials came from the US Marine Corps, which saw the system, together with zero-length rocket launchers for take-off, as being a way of getting high-performance jets ashore in the immediate aftermath of an amphibious assault. To further the project a flexible deck was erected at the US Navy test establishment at Patuxent River where trials were conducted with a number of US aircraft including the F9F Panther. Ultimately, the Marine requirement was to be met more than a decade later by a new generation of VTOL (Vertical Take Off and Landing) aircraft in the shape of the Harrier, but this is outside the scope of this book.
Although work on the rubber deck finally petered out, the system did have one advantage over conventional deck operations, which partly accounted for the fact that the Royal Navy persevered with the trials. In the 1940s any aircraft that failed to engage the arrester wires would either end up hitting the crash barrier amidships, or missing both wires and barrier and ending up crashing into the forward deck park with calamitous results. On the other hand, because of the technique employed in landing on the rubber decks, in which the aircraft was flown straight and level at a constant airspeed on the final stages of the approach, if it missed the wire it was a simple matter for the pilot to continue to overfly the deck and other aircraft before climbing away for another approach. Such a facility was obviously desirable and a more elegant and simple solution was eventually discovered, partly stemming from the rubber deck concept. In August 1951 a conference was set up to consider how undercarriage-less aircraft could be operated at sea and the rubber deck featured prominently in the discussions, which were chaired by Captain Campbell RN. It was agreed that the elimination of the crash barrier was a very useful attribute but in order to provide more protection for the forward deck park, Campbell made a proposal that the rubber deck be angled some 10 degrees off the ship’s centreline and he produced a hand-drawn sketch to illustrate his ideas. At the time it was accepted as one of several possible solutions but no decision was taken at the conference. However, one of the delegates was an RAE scientist, Lewis Boddington, who had been involved in the trials at Farnborough and aboard HMS Warrior. After giving the matter some thought he realised that the principle of angling the landing deck away from the axis of the ship could actually be applied to ordinary carrier landings by conventional aircraft. Within three weeks he had drawn up plans to adapt the new carrier Ark Royal to accommodate a 10-degree angled deck, which he presented to the Director of Naval Construction. While this was being considered, Boddington and Campbell arranged for the light fleet carrier HMS Triumph to undertake trials of the new concept. Modification of the ship was limited to removing the flight deck’s axial white centerline markings and replacing them with a new centreline offset 10 degrees to port. The arrester wires were left at their normal alignment as they were not required for the intended demonstrations, which consisted of touch and go landings only. The trials were a great success and the concept obviously had the potential to completely revolutionise flight deck operations, as well as making a major contribution to flight safety.
Despite this, the ever-cautious Admiralty while recognising the implications of the system, initially decided that it was not worth modifying existing carriers but would wait until a new generation of carriers was ordered. However, this view was soon modified by the actions of the US Navy who, as will be related, recognised the angled deck as a heaven-sent solution to a whole series of problems associated with the operation of heavy jets at sea. By the beginning of 1953 they had completed conversion of the Essex class carrier USS Antietam (CV36) to incorporate a fully angled deck and the ship was generously made available to the Royal Navy in the summer of that year for trials in the English Channel. The results fully confirmed the benefits of the angled deck and the Admiralty was convinced of the necessity to adapt existing ships and to so modify those still under construction. The first Royal Navy carrier to be equipped with an angled deck was HMS Centaur, the first of a class of three ships developed from the Colossus and Majestic class light fleet carriers. Centaur had been completed in September 1953 but almost immediately was taken in hand for the necessary modifications, which, in her case, were limited to painting a deck centreline offset by 5.5 degrees and realigning the arrester wires. A modest deck edge extension was added amidships on the port side, necessitating the removal of three twin 40 mm mountings. In this form the ship was back in service in the autumn of 1954, although her initial air group comprised piston-engined Sea Furies and Avengers, the first jet squadrons not embarking until 1955 (803 and 806 Squadrons equipped with Seahawks). The first British carrier to have an angled deck incorporated while under construction was HMS Ark Royal whose completion was delayed by two years to allow this and other new equipment to be fitted. Launched in May 1950, she consequently did not commission until February 1955.
Amongst the new equipment installed in Ark Royal was another British invention - the steam catapult. At the end of World War II all British carriers of the Illustrious and Colossus/ Majestic classes were fitted with BH.III hydro-pneumatic catapults. In these installations the power was provided by compressed air driving a piston within a cylinder. The piston’s movement was transferred to a launch trolley running in a track set in the flight deck by means of a complex system of wires and pulleys, giving an 8:1 increase in speed and travel. The trolley track in all BH.III installations was 140 feet 9 inches long and on completion of the launch the whole moving mass was brought to a halt hydraulically, the piston entering a water-filled cylinder and forcing the liquid out through apertures. Hydraulic power was then used to push the piston back to its start position ready for the next launch. Incredibly, the moving parts of the catapult weighed no less than 15,000 lb, as much as most of the aircraft that were being launched. The final versions of the BH.III could accelerate a 20,000 lb aircraft to a speed of 66 knots but maintenance was a major issue as the wires needed replacing after approximately 900 launches and their replacement could take up to two days’ work. Further development of this type of catapult resulted in the BH.V, which could accelerate a 30,000 lb aircraft to 85 knots and these were intended for the Majestic, Centaur and Ark Royal class carriers.
It is not often realised that although these catapults were hydro-pneumatic in operation, the power to compress air and drive the hydraulic pumps was derived from steam turbines, which accounted for a significant proportion of the available boiler output when a rapid series of launches was made. As early as 1936 Mr C Mitchell, an engineer working with MacTaggart Scott who produced the Royal Navy’s catapults, proposed a much simpler form of catapult in which gas pressure (steam or air) drives a piston along a tube. Attached to the piston was a traveller that projected through a slot in the top of the piston, gas losses being prevented by fitting a flexible seal, which was opened and closed as the piston passed. At the time the idea was thought impracticable (although Brunel had used it in his atmospheric railway in the 1840s) and no further work was done until 1944 when Mitchell (then a Commander (E) RNVR) inspected German V-1 launch sites and realised that the catapult was very similar to his own patented design.
Trials with a captured German catapult re-assembled at Shoeburyness showed its potential to launch the heaviest naval aircraft and development of a shipboard steam catapult was authorised in 1946. After various trials, a flexible steel strip was used to seal the slot and it was decided to use a twin-cylinder configuration for improved efficiency. The resulting BS4/5 catapult would eventually be capable of accelerating a 50,000 lb aircraft to a speed of 105 knots, enough to cope with any naval aircraft then contemplated. Furthermore, the total installation was some 50 tons lighter than the BH.V and steam consumption was considerably less due to its more efficient direct action. Nevertheless, some of the figures are startling. The moving parts weighed around 10,000 lb and had to be brought to a standstill in only seven feet. In dispersing this amount of energy an instantaneous work rate of three million horse power was generated! As soon as it came to rest, the piston could be returned rapidly to its start position while a second aircraft was taxied into position. Here, retractable ramps acted as chocks under mainwheels, inset rollers allowed the aircraft to be positioned precisely on the catapult track, and a later refinement was the provision of retractable blast screens behind the aircraft to prevent damage to subsequent aircraft as engines were run up to full power. A well drilled catapult team could launch an aircraft every forty seconds from a single catapult and this rate could be halved if twin catapults were in operation.
The first sea trials of the steam catapult were carried out aboard the light fleet carrier HMS Perseus, which had been completed as an aircraft repair ship and did not normally have facilities for operating aircraft. During 1949/50 she was fitted with a steam catapult, which was installed below a raised platform on the forward section of the flight deck. For trials purposes aircraft were hoisted aboard by crane, being parked and prepared on the after section. Over the next two years a total of 1560 launches were successfully carried out, although 1,340 involved dummy loads or unmanned aircraft. The latter were drawn from stocks of surplus or time-expired airframes, which had their outer wing panels removed so that they would not sustain flight after the launch. At least that was the idea, but more than one of these old war horses showed a reluctance to come down once in the air and one Seafire actually started a climbing turn to starboard before diving back towards the carrier. Fortunately it ran out of fuel and crashed into the sea short of the carrier - much to the relief of all on board. Some of the dummy loads included a large water tank fitted with wheels and nicknamed ‘Flying Flossie’. This had the advantage that it could be filled with varying amounts of water to simulate different aircraft weights and could be recovered for further trials, unlike the aircraft, which were strictly one shot.
The final proving trials involved a total of 166 manned aircraft and this went off without a hitch. Pilots reported a much smoother acceleration than was imparted by the conventional hydro-pneumatic catapults, which tended to impart a series of jerks as the cables took the strain of the launch. The experimental BXS.I steam catapult installed aboard HMS Perseus was capable of accelerating a 30,000 lb aircraft to a speed of 90 knots, but the later BS4 and 5 subsequently installed in British carriers were capable of launching 50,000 lb aircraft at speeds up 105 knots. The total of manned aircraft launches included a series made by US Navy aircraft when the ship visited the United States at the end of 1951 to demonstrate the new (and highly secret) technology. Some of the latest US Navy jets, including Panthers, Banshees and Skyknights, were successfully launched as well as older stalwarts such as the piston-engined Corsair and Skyraider. Once again, the trials were a resounding success and the US Navy immediately adopted the steam catapult for installation aboard its own ships.
The third major British contribution to jet carrier operations was a method to provide guidance to pilots making an approach to land. It was crucial that the pilot landed his aircraft centrally amongst the arrester wires at the correct speed, otherwise there was every chance of missing the wires or else over-stressing the arrester hook, which could shear off, leaving the aircraft careering down the deck. The traditional method of providing assistance was by means of a Deck Landing Officer (DLO) who would stand on the edge of the flight deck giving signals to the pilot by means of coloured or illuminated bats. A sequence of signals could indicate if a pilot was too high or too low, or whether correctly lined up. If all looked good the DLO would give the ‘cut’ signal at the appropriate moment and the aircraft would settle onto the deck and catch one of the wires. The DLO task required a considerable amount of skill (it was normally carried out by a practising pilot) and also a high degree of trust from the pilots concerned. One problem encountered by the Royal Navy towards the end of World War II when its carriers deployed to the Pacific was that the US Navy’s signals were diametrically opposite to the British. Thus American raised bats meaning ‘You are too low, Fly Up’ would be interpreted as ‘You are too high, Fly Down’. It took a little while and a few incidents before this one was ironed out (the Royal Navy adopted the US system). Also, the system was inevitably subject to human error, relying heavily on the skills of the individuals concerned, and it was difficult to execute and follow in poor weather conditions or at night.
A mechanical pilot-interpreted device would overcome a lot of these problems and a suitable installation was devised by Commander HCN Goodhart RN. Like many successful inventions, this one was based on a straightforward principle applied in a practical manner. In this case the approaching pilot would see a large mirror at the side of the flight deck as he approached to land on. In front of the mirror was a powerful spotlight whose beam was reflected towards the pilot. If approaching at the correct angle the pilot would see the reflection of the spotlight, which would be in line with fixed datum lights on either side of the mirror. If he went too high the blob of light (or ‘meatball’ as it was universally named) would appear to rise above the datum lights, or drop below if the pilot was too low. In addition, as the mirror was concave it actually caused the meatball to elongate vertically, forming a line of light with a bright centre, and this would move across the mirror depending on whether the pilot was correctly lined up or offset to the right or left. After successful shore trials, a Mirror Deck Landing Sight (MLDS) was installed aboard HMS Illustrious in October 1952 and over 100 landings were made without difficulty. The MLDS was adopted for general use and was fitted to all British carriers from 1954 onwards and, once again, was also taken up by the US Navy. In later years, this device was developed into the Deck Landing Projector Sight (DLPS), which operated on a similar principle but the mirror was replaced by a series of projected light beams that were variously visible to the pilot depending on his relative position. The DLPS was also fitted on a stabilised mounting, which gave a much more steady indication to the pilot when the ship was pitching and rolling. However, it was not introduced into service until 1959, after the period covered by this book.
As it was the Royal Navy that introduced these pioneering concepts, it is relevant to look at the British carriers that came into service in this period. It is a sad fact that no purpose-built conventional aircraft carrier was laid down in Britain after 1945 until the current CVFs (Future Aircraft Carriers), which will not enter service until around 2015. HMS Invincible of Falklands fame and her two sister ships were originally designed as helicopter-carrying cruisers and the addition of the STOVL (Short Take Off Vertical Landing) Sea Harrier was a fortuitous afterthought so they do not qualify as full-blooded carriers. As has already been recounted, the Royal Navy’s carrier fleet in the early post-war years consisted of some of the Illustrious class fleet carriers and the Colossus class light fleet carriers. In the meantime work progressed slowly on two large carriers that were all that remained of original plans to build four Audacious class ships. The first pair, Audacious and Ark Royal, were laid down in 1942 and 1943, while work on Eagle commenced in April 1944 but the fourth ship (to have been named Africa) was never started. In January 1946 work on Eagle was halted and the contract cancelled, although the name was transferred to the first ship (Audacious), which was then launched as HMS Eagle in 1946. The name of course perpetuated the memory of the carrier sunk in the heroic Operation Pedestal, the largest of all the Malta convoy battles. Ark Royal spent a considerably longer period on the slipway and was not launched until 1950.
Although launched in 1946, HMS Eagle was not completed until October 1951. Despite this long time scale very few improvements were incorporated and she substantially conformed to the original design. The axial flight deck was just over 800 feet long and 112 feet wide. Two BH5 hydro-pneumatic catapults were installed forward and eight sets of double arrester wires aft. The catapults could launch 30,000 lb aircraft up to 75 knots while the wires could cope with similar-sized aircraft at a landing speed of 75 knots and up to six crash barriers were provided as well as roller positioners for the catapults. The traditional armament of sixteen 4.5 inch DP guns in eight twin turrets disposed quadrantly was followed, although the tops of the turrets were flush with the flight deck. A secondary armament of no fewer than sixty-one 40 mm guns was carried, this including no fewer than eight sextuple 40 mm mountings, each controlled by a Mk.37 HA director. The main change over the original design was a much improved radar outfit, which included a long-range Type 960 with a novel Skyatron projected display system as well as a Type 982 fighter direction radar and Type 983 height finder radar.
HMS Eagle commissioned in March 1952 and she subsequently achieved a number of important milestones. Her original air group included 800 Squadron equipped with Attackers, the Royal Navy’s first shipboard jet fighter squadron, and during her work-up period she was host to deck landing trials of several new types, including the Seahawk, Sea Venom and the turboprop Gannet. In 1953 she embarked the first operational Seahawk squadron (806 NAS) and also the first Skyraider AEW aircraft supplied under MDAP.
Despite being the Royal Navy’s most modern carrier, HMS Eagle had been completed just before the full range of new British carrier aids had been tried and tested. However, her sister ship, HMS Ark Royal, had been considerably delayed on the building slips and was not launched until May 1950 when it was planned that she should commission in 1952. By this time the benefits of devices such as the angled deck and steam catapults were readily apparent and the decision was taken to delay her completion so that these improvements could be incorporated. Consequently she did not commission until February 1955, almost twelve years after her keel had been laid. Even then, the angled deck was only offset 5.5 degrees but this necessitated the suppression of the portside forward 4.5 inch gun turrets. A notable first for a British carrier was the inclusion of a deck edge lift on the port side amidships, although this was later removed in the course of a refit in 1959 as it was only of limited use, serving only the upper hangar deck. The ship’s first air group, embarked in June 1955, comprised two Seahawk squadrons (800 and 898 NAS), one Gannet anti-submarine squadron (824 NAS) and a flight of Skyraider AEW aircraft (B Flight, 849 NAS) together with two Dragonfly and two Whirlwind helicopters for SAR and general duties. In 1956 she was involved in deck landing trials for the new Sea Vixen and Scimitar before being taken in hand for further modifications in April. She did not recommission until November 1956, thus missing the Suez operation. Subsequently she saw considerable service, surviving until 1978 as Britain’s last conventional aircraft carrier.
In the meantime, HMS Eagle was docked in mid 1954 for a nine-month refit in which she was equipped with an interim 5.5-degree angled deck, although the forward 4.5 inch guns were retained as well as the BH5 catapults. Recommissioning in February 1955, her air group included two Seahawk squadrons (802 and 804 NAS), two Wyvern strike squadrons (813 and 827 NAS) and the first operational deployment of the Gannet anti-submarine aircraft (826 NAS). Eagle subsequently took part in Operation Musketeer (Suez operations) but it was not until 1959 that she was paid off for a substantial modernisation refit, which added a fully angled deck and steam catapults as well as several other features. This refit took over five years and was not completed until 1964 - well outside the scope of this book. Suffice to say that the ship’s full potential was finally realised and she gave excellent service until prematurely laid up in 1972.
Also entering service in the early 1950s were the three Albion class light fleet carriers, which represented a development of the Colossus/Majestic class. The main improvement was more powerful machinery, more than doubling output to 76,000 shp and raising maximum speed from 24 knots to almost 28 knots. Some armour plating was applied to vital areas such as the boiler and machinery rooms, and the magazines, while the flight deck was slightly enlarged to measure 733 feet by 103 feet. More significantly, hangar headroom was increased to 17.5 feet and a complement of fifty aircraft was anticipated. Original plans called for eight ships but in the event only four were laid down in 1944/5 and the remainder were cancelled after the war. Even work on those under construction was slowed down so that Albion, Bulwark and Centaur were not launched until 1947/8, after which they were laid up awaiting a decision on their future. The fourth ship, originally named Elephant but renamed Hermes, had an even more extended period in the slips and was not launched until 1953 and did not commission until 1959, having been under construction for some fifteen years! Admittedly, when she did enter service she was equipped with a fully angled deck, steam catapults, a deck edge lift and a sophisticated radar system, but her subsequent career is outside the scope of this book.
The remaining three ships were eventually completed in 1953/4, their survival being in no small part due to the hangar headroom, which exceeded that of the Illustrious class then being retired. The original design had included four twin 4.5 inch DP gun turrets disposed quadrantly but these were deleted and the defensive armament was to comprise thirty-two 40 mm guns. A very comprehensive radar outfit was shipped, including a Type 960 search radar, two Type 982 fighter direction radars and a Type 983 height finder. The first to complete was HMS Centaur, which commissioned in September 1953 but after initial trials she was taken in hand at Portsmouth dockyard where an angled deck was installed. The work required to achieve this was kept to a minimum and involved a narrow extension to the port side of the flight deck amidships necessitating the removal of three twin 40 mm mountings. The deck centreline was offset 5.5 degrees and the arrester gear and barriers were re-aligned to conform. By the autumn of 1954 the work was complete and Centaur deployed to the Mediterranean with an initial air group comprising piston-engined Sea Furies and ASW Avengers. It was not until the following year that jets came aboard in the shape of Seahawks of 805 and 806 Squadrons.
Completion of the other two ships, Albion and Bulwark, was delayed so that the angled deck could be installed. When Albion commissioned in May 1954 it was claimed that she was the first new-build carrier in the world to be so equipped. In this case the deck was angled at 5.75 degrees and she was also the first to be fitted with the mirror landing sight. Albion subsequently deployed to the Mediterranean with an air group made up of Seahawk jet fighters, Wyvern turboprop strike aircraft and piston-engined Skyraiders for AEW. Bulwark commissioned in November 1954 and initially replaced Illustrious as a trials and training ship before embarking a unique air group that consisted entirely of Seahawk jet fighters (801 and 898 NAS) backed up by Skyraider AEW aircraft and Dragonfly SAR helicopters. Both Albion and Bulwark were present in the Suez operations (November 1956) but at the end of the decade both were converted to helicopter-carrying assault ships as they were considered too small to effectively operate the new generation of naval aircraft then coming into service.
Both Albion and Bulwark retained their BH5 hydro-pneumatic catapults while operating fixed wing aircraft but Centaur was modified during a refit lasting two years from September 1956 in which steam catapults were fitted. Although she subsequently operated Scimitars and Sea Vixens, the numbers that could be embarked were limited and Centaur was eventually retired in 1965.
Thus by 1955 the effective Royal Navy carrier strength consisted of the two large fleet carriers, Ark Royal and Eagle, and the three Albion class light fleet carriers. In addition, a few of the earlier Colossus class were retained for a while in secondary roles, although one of these, HMS Warrior, was fitted with an angled deck while under refit in 1955/6. In order to boost this force it had been proposed to modernise some of the Illustrious class but in the event only HMS Victorious was taken in hand. Illustrious and Formidable were also considered for modernisation but with the limited funds available the Admiralty decided to concentrate on the newer ships then under construction and, in any case, a survey of Formidable revealed that she was in poor condition, partly due to wartime damage that had been hastily repaired at the time. However, work progressed on Victorious and from March 1950 she became a semi-permanent fixture at Portsmouth dockyard. Some major alterations were made, including cutting the ship in half so that she could be lengthened by 30 feet while her beam was increased by 8 feet. Eventually new machinery was installed and virtually every compartment was stripped and refitted. Originally it was intended that the ship would be able to operate an air group of fifty-four post-war jet aircraft from a conventional axial flight deck. However, the development of the angled deck and steam catapults resulted in the design being modified to accommodate these features and it was not until 1958 that Victorious finally commissioned. At that time she was the only Royal Navy carrier with a full angled deck, it being canted 8.75 degrees off the centreline. She was also the first to be fitted with the new Type 984 ‘3D’ radar and all in all she was a very valuable addition to the fleet, although her subsequent career is outside the scope of this book.
In contrast to the Royal Navy, the US Navy not only retained the bulk of the wartime Essex class carriers, but was able to constantly modify and upgrade them so that many remained in frontline service well into the 1970s. The upgrading of some ships under the SCB-27A programme has already been covered. In 1949 further conversions designated SCB-27B were proposed but shortage of funds (even the mighty US Navy suffered from financial constraints but nowhere near as badly as the British with their depressed post-war economy) prevented their implementation. However, by 1951 it was becoming apparent that a further upgrade was still required if these ships were to be able to operate some of the newer types likely to enter service such as the McDonnnell F3H Demon. One major change was to be the installation of new C-10 catapults using explosive powder charges, replacing the H-8 hydraulic catapults. Mk.VII arrester gear capable of handling heavier aircraft would replace the earlier Mk.V wires and jet-blast deflectors behind the catapults were to be fitted for the first time. The deck was strengthened to accommodate parked aircraft weighing 60,000 lb and an additional deck edge lift was installed on the starboard side aft of the island, replacing the previous after centreline lift, and this arrangement would considerably speed up deck operations. All these improvements added weight and the full load displacement rose to 42,000 tons, necessitating an increase in the hull bulges, which, while maintaining stability at acceptable levels, reduced speed to just over 30 knots.
One novel feature of the SCB-27C project was the manner in which jet fuel capacity was substantially increased. It had been found that mixing aviation gasoline (Avgas) as used by the piston-engined aircraft with the ship’s own ‘heavy-end’ bunker oil produced a usable jet fuel. As the bunker oil was non-volatile it could be stowed in normal tanks without the extensive protection required for the more volatile aviation fuels. Using this method up to 739,000 US gallons of jet fuel could be made available, although a knock-on effect was a reduction in the ship’s cruising range from 11,500 nm to around 8,500 nm at 20 knots. However, given the extensive tanker support available to the US Navy, this was not a serious drawback. Even while the SCB-27C scheme was under consideration, the US Navy learnt of British developments such as the steam catapult and the angled deck. Although the angled deck had very obvious advantages and was quickly adopted, the steam catapult was actually something of a life saver for the US Navy as the C-10 catapult had proved unsuccessful and could possibly have caused the abandonment of the SCB-27C project if the British alternative had not been available. Steam catapults were subsequently manufactured under licence in the United States, initial versions being designated C-11, and these were installed in the SCB-27C ships.
As far as the angled deck was concerned (initially termed ‘canted deck’ in US Navy parlance), the Americans were keen to try out the idea in practice as soon as possible and the USS Antietam was selected for the prototype installation. This ship had been completed in November 1945 but had been laid up in reserve in 1949 before being re-activated for Korean War service in 1951. In May 1952 she was at New York Navy Yard where a 10.5-degree angled deck was fitted, the work being completed in April 1953. She was immediately involved in extensive trials to test the new concept and these were an outstanding success. As part of the trials programme she visited the UK in June 1953 for a week of operations with current British jet aircraft such as the Seahawk and Attacker. Subsequently Antietam remained in service until 1963 but she was not further modified.
However, the introduction of the angled deck into the American ships resulted in another modification programme designated SCB-125. While the main feature was the new deck layout a number of other improvements were incorporated. Up to this point all Essex class carriers had featured an open bow on which were mounted several 40 mm AA guns. However, this arrangement was prone to damage in severe sea conditions so the SCB-125 programme introduced a fully enclosed bow, known as a ‘hurricane’ bow, which was remarkably similar to the profile adopted by all British carriers from before World War II. Other features that assisted flight deck operations included improved lighting and strengthened crash barriers, the latter still being retained for emergency use, although they were not required in normal flying operations. The number of arrester wires was halved due to the fact that with the angled deck a pilot had the option of a go around, or ‘bolter’, if he missed the wires.
The application of the various modification programmes to the ships of the Essex class inevitably resulted in several variations. Between 1948 and 1953 eight ships (Essex, Yorktown, Hornet, Randolph, Wasp, Bennington, Kearsarge, and Lake Champlain) all underwent the basic SCB-27A programme, while the USS Oriskany was actually completed to this configuration in September 1950. Another three ships (Intrepid, Ticonderoga and Hancock) were modified as SCB-27C between 1951 and 1954 but then subsequently received the SCB-125 modifications, including the angled deck in further refits between 1955 and 1957. Three more ships received the full SCB-27C and SCB-125 modifications in a single refit between 1951 and 1955, these being Lexington, Bon Homme Richard and Shangri La. The Oriskany, originally completed as an SCB-27A, was modernised between 1957 and 1959 under a scheme designated SCB-125A, which included the laying of a metal flight deck in contrast to the traditional wooden deck surface on all other Essex class ships. Three ships received no modifications in their careers as conventional fixed wing aircraft carriers, these being Boxer, Princeton and Valley Forge, although between 1959 and 1961 they were converted to helicopter assault ships (LPH) along the lines of the successful British conversions of the smaller Albion and Bulwark. Finally, five ships (Franklin, Bunker Hill, Leyte, Tarawa and Philippine Sea) were not modernised at all during their post-war careers, the first two having received severe damage during World War II, although both were repaired.
The Essex class carriers with the SCB-125 modifications remained in service up to the time of the Vietnam War and proved capable of operating the new combat aircraft that were entering service or under development in the early 1950s (and are described in the next chapter). These included Cougar, Demon and Crusader jet fighters, and the Skyhawk and Skywarrior attack bombers. However, those that were involved in the Korean War, although operating the first generation jets such as the Panther and Banshee, were mostly the later ships that remained unmodified. The first angled deck ship to deploy with an operational air group was the USS Shangri La, which recommissioned in January 1955, well after the end of hostilities. In summary, in the post-war era the US Navy reaped the benefit of a large wartime construction programme and was provided with a carrier force that proved capable of operating the newer, heavier and larger aircraft that came into service in the decade after 1945. Partly this was because the US Navy had always prioritised on the aviation requirements when designing aircraft carriers, in contrast to the Royal Navy in which the compromises required between the demands of the ship and its air group were not always decided in favour of the aviation interests. Consequently, as aircraft grew in size and performance the basic requirements such as flight deck size, lift numbers and capacities and hangar stowage were already in place.
Also, of course, the US Navy possessed the three large Midway class carriers, which were much bigger than the Essex class and had no difficulty in accommodating new aircraft. Consequently, many of the early jet operations took place aboard these ships. Nevertheless, even these great ships required updating to meet new challenges and in 1947/8 all three had their flight decks strengthened to allow them to operate the AJ-1 Savage nuclear bomber, which was then undergoing flight testing prior to its operational debut in 1950. At around that time the Midway class was also fitted with facilities to allow it to launch Regulus 1 missiles. These were an early version of the cruise missile concept and after a rocket-boosted launch from a platform erected on the carrier flight deck, they used a jet engine to give the missile a range of around 200 miles carrying a 120-kiloton nuclear warhead. Although the launcher was a simple structure, ship modifications required spaces for missile stowage and assembly, as well as secure magazines for the nuclear warheads.
As with the Essex class, the three Midways underwent modernisation programmes, of which the first was designated SCB-110. The Franklin D Roosevelt was docked from May 1954 to April 1956 and Midway followed in September 1955, her conversion taking almost exactly two years. The SCB-110 programme included the construction of an angled deck offset at eight degrees and having a length of 482 feet. Two C-11 steam catapults were fitted and a hurricane bow profile was adopted. The lift arrangements were considerably altered, the after centreline lift was removed and replaced by a new deck edge lift on the starboard side, while a second edge lift on the port side was positioned at the forward end of the angled deck. New arrester gear with a reduced number of wires, as in the Essex refits, was also installed and aircraft fuel stowage considerably increased. All this added considerable weight and as partial compensation some of the armament was removed leaving a total of only ten 5 inch/54 cal and twenty-two 3 inch/ 5 cal AA guns. The aircraft capacity was now around eighty and the squadrons embarking were to be equipped with the new range of naval combat aircraft, including the F3H Demon, F8U Crusader, A3D Skywarrior and A4D Skyhawk, as well as the ubiquitous AD Skyraider.
The third ship, USS Coral Sea, did not undergo modernisation until 1957-60, outside the scope of this book. However, it is of interest to note that her SCB-110A programme involved the removal of all centreline lift lifts, which were replaced by one deck edge lift on the port side amidships, and two on the starboard side situated forward and aft of the island superstructure. An additional C-11 steam catapult was installed along the angled deck to supplement two bow catapults. Between 1966 and 1970, Midway underwent a further modernisation (SCB-101.66) but cost issues resulted in plans for the Franklin D Roosevelt to be similarly modified being dropped. Because of this she was the first of the class to be paid off, in December 1977, but the others had much longer careers. Coral Sea lasted until 1990 and Midway took part in the first Gulf War in 1991 before being retired the following year after forty-seven years’ service - a remarkable achievement, especially when it is considered that the British Ark Royal and Eagle, laid down at the same time, only achieved twenty-three and twenty-one years in service. In fairness it should be pointed out that this was more due to differing political outlooks rather than any inherent problems with the ships themselves.
Today the US Navy operates a fleet of nuclear-powered super carriers and all the ships of World War II origin have long since been retired, mostly cut up for scrap. However, the concept of the super carrier had its origins as far back as late 1945 when opinion in the US Navy was moving towards a requirement for a naval bomber that could weigh as much as 100,000 lb and be capable of carrying a 12,000 lb bomb over a radius of 2,000 miles. This was almost in the same class as the Boeing B-29, the Air Force’s standard bomber, and it would obviously require a very large ship from which to operate. The concept of a pure bomber with a strategic capability was new to the US Navy. Previously it had concentrated on weapons systems such as torpedoes and conventional bombs that could sink ships, and had no requirement for anything else. However, in the post-war era naval air power was much more likely to be deployed against land targets and the US Navy became embroiled in a struggle with the United States Air Force (formerly the US Army Air Corps until 1947) over supremacy in the strategic nuclear strike role in which the Navy was determined not to lose out.
A sketch bomber design known as ADR42 had a wingspan of 116 feet, reducing to 44 feet with wings folded, and the US Navy wanted a ship that could carry and operate twenty-four of these aircraft. The result was a very large aircraft carrier with an overall length of 1,090 feet, a hull beam of 130 feet and an overall beam of 190 feet measured over the flight deck and projecting sponsons. The standard displacement was estimated at 66,850 tons, rising to 78,500 at full load. Despite the sheer size, the ship would be capable of 33 knots with a 280,000-shp four-shaft machinery installation. Defensive armament would comprise eight single 5 inch/54 cal and six twin 3 inch/50 cal AA guns. However, the most interesting feature was the flight deck, which was entirely flush with no superstructure, the ship being conned from a small platform forward on the starboard side, and smoke from the boilers being vented through outtakes on either side of the after end of the flight deck, rather in the manner common to many Japanese carriers in World War II. In order to launch a strike in a reasonably quick time frame, four catapults were envisaged, two in the bow and one on each side amidships angled outboard. The latter arrangement was almost a forbear of the angled deck concept but at the time no one thought of its application for landing aircraft. Although the original expectation was that the bombers would have to be stowed in a deck park, the sheer size of the ship allowed a large hangar with a 28-foot headroom - greater than subsequent carriers, which only have 25 feet. By 1947 when the design was being refined the draft characteristics showed a revised air group of only twelve ADR42 bombers but up to fifty-four F2H Banshee jet fighters for escort purposes. Alternatively up to eighteen smaller ADR45A attack aircraft could be accommodated. The latter were quoted as having an all-up weight of 57,000 lb and were to be powered by four turboprops giving a radius of 750 miles. Allocated the hull number CVA58 and named USS United States, the ship was laid down on 19 April 1949 at Newport News. In the meantime the power struggle between the Air Force and the US Navy reached a climax with the former victorious, securing funds for a strategic bomber force so that work on the carrier ceased after only four days and the contract was cancelled.
However, the work put into the design of the flush-decked carrier was not all lost and in 1950 studies began for a new slightly smaller 60,000-ton carrier. The outbreak of the Korean War released funding for the project, which was based around the Douglas A3D Skywarrior jet bomber that began development in 1949 and subsequently flew in 1952. The flush-deck layout was initially retained and still featured when the first of a class of four ships, the USS Forrestal (CVA59), was laid down in July 1952. The four-catapult layout was also retained but these were the C-10 powder charge type, which were to prove unsatisfactory in operation, quite apart from the requirement to provide additional magazine space to stow the large number of charges required. Although the catapults were canted out to port and starboard, landing aircraft were still intended to land along the deck axis. However, the adoption of the British concept of an angled deck permitted a conventional island superstructure to be built up on the starboard side of the flight deck, the catapult on that side being moved across to the port side where one catapult was almost parallel to the ship’s axis and the other was aligned with the 8-degree offset angled deck. This arrangement permitted two aircraft to be positioned simultaneously on the portside catapults before being launched in turn. Again, the adoption of the steam catapult was a godsend and solved many problems that would have arisen if the powder charge type had been fitted.
As completed in October 1955, the USS Forrestal displaced 60,000 tons in standard trim but this rose to 78,000 tons at full load. At that time she was the largest warship ever built and could carry around ninety aircraft. Her first air group comprised three fighter squadrons equipped with F9F Cougars or F2H Banshees, two attack squadrons with A4D Skyhawks and the indestructible AD Skyraider, and one heavy attack squadron with the A3D Skywarrior twin jet bomber. In addition there were small numbers of SAR helicopters and AEW aircraft as well as a photo reconnaissance detachment. Although the original Forrestal class numbered only four ships (all in service by 1959), they were followed by four more Improved Forrestal class and although there were some significant differences among the individual ships, they all followed the same basic design. Indeed, the first nuclear-powered carrier, USS Enterprise (CVAN65), differed little in overall layout and the subsequent Nimitz class again conformed, although slightly larger. In effect therefore, the optimum carrier size and layout for the operation of modern naval jet aircraft had been established by 1955. Since then there have been few major changes other than the adoption of nuclear power. Even the latest US carriers laid down in the twenty-first century will retain the overall configuration, although the ships’ systems based around new electronics and massive computing power offer a Control, Command and Communication system that is light years removed from that available in 1955. One other change is that the long-serving steam catapult will give way to an Electro-Magnetic Aircraft Launching System (EMALS), which is currently under development but shows great promise.
Pilot’s view landing aboard the carrier HMS Centaur which has been modified to incorporate an angled deck and has been fitted with the Deck Landing Mirror Sight prominent on the port side. Note the clear deck available ahead for a ‘bolter’ if none of the arrester wires trapped. (Fleet Air Arm Museum)
A close up view of a Deck Landing Mirror Sight (DLMS) installed ashore at RNAS Brawdy for training purposes. Reflected in the mirror is the reference light installed further along the runway and Seahawk about to land. (Fleet Air Arm Museum)
The ultimate development of the DLMS was the fully stabilised Deck Landing Projector Sight. As can be seen this was a much more sophisticated and complex piece of equipment. (Fleet Air Arm Museum)
The completion of HMS Ark Royal was delayed for almost two years so that she could be fitted with an angled deck. When finally commissioned in early 1955, she was also the first British carrier to incorporate a deck edge lift. (Author’s Collection)
In the post-war era the US Navy was in the fortunate position of having numerous Essex class carriers available. This is USS Leyte (CV.32) which commissioned in April 1946 and is substantially unaltered in this February 1949 photo. The carrier fleet was augmented by a fleet train of auxiliary vessels which ensured that the carrier groups could remain at sea for long periods. (US National Archives)
The USS Shangri La (CV.38) was an Essex class carrier completed in September 1944. Between 1952 and 1955 she was modernised under the SCB-27C and SCB-125 schemes which included the fitting of an angled deck, a deck edge lift on the starboard side, a fully enclosed bow and a redesigned island superstructure. In this guise she was redesignated CVA.38 and remained in service until 1971. (US National Archives)
The three large Midway class carriers were all substantially modernised in the 1950s. This is USS Franklin D. Roosevelt (CVA.42) after completion of the SCB-110 programme in 1956. (US National Archives)
The prototype Supermarine 510 flown by Lieutenant J. Elliott RN makes the world’s first deck landing by a swept wing aircraft aboard HMS Illustrious on 8 November 1950. (Fleet Air Arm Museum)
The twin engined Supermarine 508 first flew on 31 August 1951 and is shown here during deck landing trials aboard HMS Eagle in May 1952. A swept wing development was the Type 525 which eventually went into production as the Type 541 Scimitar. (Fleet Air Arm Museum)
A formation of de Havilland Sea Vixen FAW.2s. This was the final production version of the DH.110 series of twin engined all weather jet fighters, of which the prototype first flew in September 1951. However production examples did not reach front line squadrons until 1959. (Fleet Air Arm Museum)
The supersonic Chance Vought F8U-1 Crusader flew in prototype form in 1955 and entered front line service less than two years later. It was destined to provide the backbone of the US Navy’s fighter strength until gradually replaced by Phantoms from the mid 1960s onwards. One of the two prototypes is shown here aboard USS Forrestal in 1956. (US National Archives)
The McDonnell F3H Demon had a chequered career. The initial Westinghouse powered F3H-1 was a total failure and only when re-engined with a more powerful and reliable Allison J71 turbojet was its potential realised. Thus although the prototype flew in 1951, the re-engined F3H-2 did not reach squadrons until late 1956. One of these is shown being manhandled onto the catapult tranck aboard the recently commissioned USS Forrestal (CVA.59) in 1956. Note the retractable air to air refuelling probe. (US National Archives)
The Lockheed XFV-1 was one of two vertical take off fighters designed around the 5,850 shp Allison XT40 turboprop. While the Lockheed design never demonstrated the transition from vertical to horizontal flight, the rival Convair XFY-1 successfully achieved vertical take offs and landings and transition to and from horizontal flight. However both projects proceeded no further than the prototype stage. (US National Archives)
Another blind alley was the concept of a waterborne jet fighter. The twin engined Convair XF2Y-1 Sea Dart employed a hydro-ski as opposed to a more conventional planing hull but the project was cancelled in 1956. (US National Archives)
The Douglas XF4D-1 Skyhawk was revolutionary for its time - offering jet performance with a useful load carrying capacity, all in an aircraft weighing in at half that of other contemporary designs. First flown in June 1954, almost 3,000 Skyhawks were built and some remain in service today. (US National Archives)
The US Navy finally achieved a credible nuclear capability with the twin engined Douglas A3D-1 Skywarrior jet bomber. First flown in October 1952, the Skywarrior was by far the largest and heaviest naval combat aircraft ever produced up to that time. (US National Archives)
A production Skywarrior aboard USS Forrestal in 1956 demonstrates the folding tailfin as well as folding wings to enable the aircraft to fit in the standard carrier hangars. (US National Archives)
The ultimate British naval jet bomber was the Blackburn Buccaneer which first flew in 1958 although its origins went back to a far sighted Admiralty requirement issued in 1951. (Fleet Air Arm Museum)
The Fairey Gannet ASW aircraft was unique in being powered by the Double Mamba turboprop driving contra-rotating propellers. One half of the engine could be shut down to extend range and endurance. The Original Fairey GR.17/Type Q prototype provided accommodation for a pilot and observer but production aircraft featured an additional cockpit for a third crew member. (Fleet Air Arm Museum)
The Grumman F9F-7 Cougar was a swept wing development of the F9F-5 Panther and offered a considerable increase in performance. Although the prototype flew in 1951, Cougars entered service too late to see action in the Korean War. (US National increase Archives)
The Chance Vought F7U Cutlass was an impressive and futuristic looking design although its in service record was marred by numerous accidents. (US National Archives)
The three Midway class carriers which entered service between 1945 and 1947 were the largest US carriers built up to that time and were well able to cope with the first generation of jet aircraft. Shown here is the name ship of the class, USS Midway (CV.41), in 1949. Note the Sikorsky HO3S helicopter on the foredeck. (US National Archives)