other projects which were given higher short-term priority. Their outfit reflected the progress made since the first ship was completed in 1940. Both had extensive air and surface warning, target indication and fire-control radars, and a considerably enhanced close-range armament that eventually included both 40mm Bofors and 20mm Oerlikon mountings. The 4.5in gun turrets were modified with flat tops and set slightly lower so that they did not obtrude above flight-deck level as they had done on the earlier ships, although their positioning still caused bottlenecks in deck width that adversely affected aircraft ranging.
Air arrangements were modified and the arrester wires, catapult and lifts were all strengthened to operate 20,000lb aircraft. The layout followed Indomitable in that the forward lift was larger but served only the upper hangar. The smaller after lift served both the upper and lower hangars, and the lower hangar was extended 40ft further forward than that of Indomitable. The decision to accept the lower hangar height in both hangars followed acceptance that these ships would not be required to strike down aircraft on floats. They were the largest British aircraft carriers built to date and the first that were not required to operate floatplanes. While 14ft seemed a reasonable compromise in 1938, it soon limited the type of aircraft that could be embarked, and neither ship could embark Corsairs when they became available under Lend/Lease arrangements. With insufficient numbers of Hellcats available in 1945, both ships had to operate the fragile and short-ranged Seafire, which could be embarked in large numbers but was unsuited to operations in the Pacific. Some increase was made in the quantity of avgas that could be stowed, but these ships had enough for only five sorties for each aircraft embarked, hardly sufficient for sustained strike operations. Stowage for air weapons was also barely adequate by 1945.
Both ships were originally designed to go through the Panama Canal, but during their construction it became obvious that it was important to achieve the maximum amount of space in the ranging area aft, and the deck was widened in the space forward of the after 4.5in turrets, allowing up to three more aircraft in the range. The structure to support it, however, precluded passage through Panama.
Still more space was made available by making the top of the 4.5in turrets flat and flush with the flight deck, since it was realised that firing across the deck was impractical and likely to damage aircraft. The ability to wheel or taxi aircraft across the turret tops had the effect of widening the deck in the area that had been described as an undesirable ‘gully’ in the earlier ships of the group.
Implacable being towed down the Clyde from her builder’s yard in 1944. (AUTHOR’S COLLECTION)
There were many design weaknesses which limited the usefulness of these large ships. The fourth machinery unit required considerably more stoker-mechanics than the earlier group designs, and the number of radars and short-range weapons added during build added still further to the size of the ship’s company that had to be accommodated. By 1945 these ships embarked forty-eight Seafires, twelve Fireflies and twenty-one Avengers, which needed roughly double the original estimate of manpower to fly, maintain and handle on deck and in the hangar. Workshops were inadequate and much of the space designed for use as the lower hangar had to be used to provide workshops and accommodation. By far the greatest weakness, however, was the hangar height of only 14ft, which proved to present too great a restriction on the type of aircraft that could be embarked. These weaknesses proved fatal after 1945, as larger and heavier aircraft came into service, and only Implacable saw operational service after 1945. The original design had failed to provide sufficient space to allow for aircraft growth in a period of dynamic advance. Consequently these two ships, which had taken five years to build and were the largest carriers yet completed for the RN, spent only three years and eighteen moths respectively in service.
Post-war modernisation plans
Implacable was meant to follow Victorious in the RN’s planned aircraft carrier modernisation programme. Originally work on Victorious was expected to last from mid-1950 to 1955 and to cost an estimated £10,335,000. Implacable was to be taken in hand in November 1953, with completion projected for April 1957 at an estimated cost of £10,460,000. As the cost and complexity of work on Victorious spiralled upwards, however, the Board took the decision that it would be cheaper to build a new ship, and work on Implacable was cancelled.
The modernisation would have entailed stripping the hull down to the lower hangar deck level, reboilering while there was access and then building up a new hangar with at least 17ft 6in clear height, over which there was to be a new deck for accommodation and offices running the whole length of the ship under the flight deck, pierced by two large centreline lifts. Finally, there would have been a new armoured flight deck, a new island and a new armament of twin USN 3in/50 guns identical to those fitted in Victorious. Clearly lessons would have been read across from Victorious, but the timescale and cost would have been far beyond the estimates. She could not even have been considered for use, unmodified, as a commando carrier, since Westland Whirlwind helicopters had a height of 15ft 4in and could not be struck down into either hangar despite their usefulness as a vehicle
‘garage’. The decision not to proceed and to seek approval to build a new ship instead was a sensible one.
Implacable’s armour protection, showing how it differed from that of the basic Illustrious design. (AUTHOR’S COLLECTION)
Implacable arrives in Sydney in 1945 with 2,200 Australian Army personnel on board, having transported them from Borneo. (Author’s collection)
Implacable Class technical details Displacement: 32,110 tons deep load Dimensions:
length 766ft 2in beam 131ft 3in draught 29ft 4in Machinery:
4 shaft Parsons geared turbines 8 Admiralty three-drum boilers 148,000shp delivering 32 knots Armament:
8 twin 4.5in turrets; 5 octuple 2pdr ‘pom-poms’; 3 quadruple 2pdr ‘pom-poms’; numerous 40mm Bofors and 20mm Oerlikon
Protection: 3in flight deck; 4.5in waterline belt; 2in hangar sides and bulkheads; 4.5in magazine sides; 3in magazine crowns Fuel: 4,690 tons FFO
Endurance: 12,000 miles at 10 knots Complement: 2,300 in 1945
Aircraft operating data
Flight deck: 760ft x 90ft armoured steel Hangars: upper 456ft x 62ft x 14ft
lower 208ft x 62ft x 14ft
Catapult: 1 BH3 – 20,000lb at 56 knots end speed Arrester wires:
9 aft each 20,000lb at 60 knots entry speed 3 forward each 20,000lb at 60 knots entry speed 3 barriers each 20,000lb with a 40ft pull-out
Lifts: forward 45ft long x 33ft wide, serving upper hangar only aft 45ft long x 22ft wide, serving both hangars Aircraft: 81 in 1945
Aircraft fuel: 94,650gal avgas
Air weapons:
as designed
54 x 18in torpedoes 120 x 500lb SAP bombs 890 x 250lb bombs
1100 smaller bombs and depth charges
0.303in gun ammunition; flares and pyrotechnics
Implacable
Implacable was ordered from the Fairfield Shipbuilding and Engineering Company on Clydeside in 1938 and laid down on 21 February 1939. She was allocated Admiralty Job Number J1672 and Yard Number 672. Work on her was suspended in 1940 when higher priority was given to the completion of destroyers and convoy escorts. After resumption of work she was launched on 10 December 1942 and eventually commissioned in Fairfield’s shipyard on 22 May 1944. After that she carried out contractor’s sea trials which revealed a considerable number of defects, these being rectified in Rosyth Dockyard between 16 June and 28 August, when she was formally accepted into service. She embarked Number 2 TBR Wing comprising 828 and 841 (Barracuda) NAS in late August and began to work-up in the Clyde areas. On 22 September 1771 (Firefly) NAS joined the air group, but the Seafire Wing intended for her was still re-equipping and training replacement aircrew after service in Furious. On 7 October she joined the HF in Scapa Flow, and a week later sailed to join ships searching for the Tirpitz, which had moved from Kaa Fjord to Tromso. A section of Fireflies located and photographed the German ship off Haakoy Island, but a request to launch a strike with Barracudas was firmly rejected by the Admiralty owing to the lack of any escort fighters. Subsequent sweeps by Fireflies damaged a 4,700-ton ship at Mosjoen and destroyed three enemy aircraft on the ground at Soreisen. On 26 October Number 24 Naval Fighter Wing, comprising 887 and 894 (Seafire) NAS, embarked and Implacable took part in Operation Athletic, strikes on Bodo, Rorvik and Lodings, during which forty Barracudas dropped 27 tons of bombs.
Implacable fires a gun salute in 1949 while serving as flagship of the Home Fleet. The slight wind from ahead is blowing the gun smoke aft, marking the firing interval. (AUTHOR’S COLLECTION)
On 28 October 1944 her Barracudas carried out the last operational airborne torpedo attack by the RN. Six enemy merchant ships were sunk, including one of 2,693 tons, and seven other ships were
damaged, for the loss of one Barracuda. Additionally, U-1060 was driven on to a reef and destroyed.
On 30 October Implacable returned to Scapa Flow and disembarked 24 Wing. She sailed again on 8 November and embarked Number 38 Naval Fighter Wing, comprising 801 and 880 (Seafire) NAS together with the same Firefly and Barracuda units as before. The air group gave cover for aircraft from escort carriers that were laying mines off the Norwegian coast. On 27 November she took part in Operation Provident, in which Barracudas and Fireflies sank two enemy ships in a convoy off Alster Island and damaged four others. Fighters damaged the escorts with cannon fire. A day later high seas damaged Implacable’s bow and she returned to Scapa Flow for minor repairs by the fleet maintenance group. On 4 December she sailed to provide cover for another HF minelaying operation, and on 8 December she took part in Operation Urbane, during which Fireflies from 1771 NAS and Wildcats from Trumpeter sank a German minesweeper. On 15 December 1944 she entered Rosyth Dockyard for a refit to prepare her for service with the BPF.
The refit was completed on 10 March 1945 and she embarked an air group comprising an expanded 38 Naval Fighter Wing with forty-eight Seafires; 1771 (Firefly) NAS with twelve aircraft and 828 (Avenger) NAS with twenty-one aircraft, the largest air group embarked in a British carrier up to that time. She sailed on 16 March to join the BPF, working-up off Ceylon in April and arriving in Sydney in May. In June 1945 she joined the other carriers of 1 ACS at the forward operating base at Manus Island as they returned from Operation Iceberg, and on 16 June she sailed for Operation Inmate, strikes against the Japanese base on Truk Island, with Ruler acting as a spare deck.
In early July Implacable worked-up off Manus in company with Victorious and Formidable, and on 6 July she sailed with task Force 37 of the BPF for operations off the Japanese mainland. The British task force joined the US Fast carrier Task Force, TF 38, off Honshu on 16 July, the combined fleets ‘stretching as far as the eye could see’ in the words of one RN pilot.
On 17 July 1945 aircraft from 1 ACS struck at targets in the Tokyo Plain, and over the next 25 days bad weather, replenishment cycles and the need to stay clear of atomic bomb attacks limited operational flying to only eight days, but Implacable’s aircraft flew over 1,000 sorties and hit airfields, shipyards, shipping, factories and railway installations. On 10 August she flew seventy offensive sorties against targets in Honshu. After replenishment on 11 August she withdrew for passage to Sydney in company with Victorious and Formidable. She arrived in Sydney on 24 August and then spent two months repatriating Allied former prisoners of the Japanese to Australia and Canada. On 18 October she sailed from Vancouver to repatriate Dutch personnel to Balikpapan in Borneo, after which she ferried Australian Army personnel home from New Guinea.
In December 1945 she carried out a defect rectification period in Sydney to prepare for operational flying once more, after which she embarked 801 (Seafire), 828 (Avenger) and 1790 (Firefly) NAS for a tour of Australian and New Zealand waters. On 23 January 1946 she arrived at Melbourne for a very successful visit in company with Indefatigable, Glory, Armada and Tuscan. On 25 January a thousand sailors from the combined ship’s companies marched through Melbourne, watched by over a quarter of a million Australians. The fleet sailed on 31 January, and Implacable was refitted in Garden Island Dockyard in Sydney. On completion she sailed for the UK on 5 May 1946, arriving at Portsmouth after disembarking the air group on 3 June. She subsequently joined the HF with a reduced ship’s company as a deck landing training carrier.
In February 1947 she took part in exercises in the Western Mediterranean with Ocean, but had no air group of her own embarked. In April 1947 she was refitted for further operational service and recommissioned in October. Her new air group included new aircraft types which were not ready, so she replaced Illustrious temporarily as a trials carrier. She underwent a further short refit in Rosyth
in October 1948 to equip her to be the flagship of the HF, emerging in December. In April 1949 she embarked her new air group, now designated the 1st Carrier Air Group and comprising 801 (Sea Hornet) and 813 (Firebrand) NAS. On 29 April she hoisted the flag of Admiral Sir Philip Vian. Her air group remained small because of a shortage of aircrew, but it was augmented for the Autumn Cruise with 702 (Sea Vampire) NAS, the jet fighter evaluation unit, which operated very successfully from the deck. In 1950 the air group was temporarily augmented by 815 (Barracuda) NAS, which was normally employed on antisubmarine trials at RNAS Eglinton in Northern Ireland.
Implacable paid off into reserve on 13 September 1950 after disembarking her air group. She was maintained by a small ship’s company and work was slowly taken forward to equip her with extra accommodation and classrooms in the former hangars to equip her as a training ship. She recommissioned in January 1952 as flagship of the HF Training Squadron, a task which involved some sea time and kept her in running condition. She was present at the Coronation Review for HM Queen Elizabeth II at Spithead on 15 June 1953, and on 10 October she sailed with a battalion of the Argyle and Sutherland Highlanders from Plymouth to Trinidad as part of a reinforcement operation to deal with a crisis ashore in British Guiana. On 19 August 1954 the battleship Vanguard took over as flagship of the Training Squadron and Implacable was destored before being decommissioned on 1 September 1954. The plan to modernise her having been cancelled, she was placed on the Disposal List and sold to breakers on 27 October 1955. Subsequently towed to Inverkeithing, she was broken up for scrap from November 1955 onwards.
Indefatigable steams up the Channel on the last leg of her journey home from the BPF in 1946. The Seafire on deck appears to have hit the forward barrier and is being removed by ‘Jumbo’, the mobile crane. (AUTHOR’S COLLECTION)
Indefatigable
Ordered from John Brown and Company of Clydebank in 1938 and laid down on 3 November 1939, Indefatigable was allocated Admiralty Job Number J1565, Yard Number 565 and was launched on 8 December 1942. She was formally completed and commissioned at Clydebank 0n 3 May 1944, after which she carried out sea trials before joining the HF at Scapa Flow in July and embarking an air group comprising 24 Naval Fighter Wing with 894, 880 and 887 (Seafire) NAS; 1770 (Firefly) NAS and 9 TBR Wing with 820 and 825 (Barracuda) NAS. Her first operational sortie was Operation Mascot, a strike against Tirpitz in Kaa Fjord which was frustrated by a smokescreen up to 800ft
which obscured the target.
Amidships detail of Implacable as she enters Vancouver with repatriated former prisoners of the Japanese in 1945.
Temporary sports pitches have been marked out on the flight deck to help keep her passengers entertained. (AUTHOR’S
COLLECTION)
Implacable coming alongside in Melbourne for a port visit in January 1946. (AUTHOR’S COLLECTION)
On 2 August she sailed for Operation Turbine, a sweep through the Norwegian Leads during which fighters strafed and destroyed German radar and communications installations ashore. A week later she provided cover during Operation Offspring with a reduced air group comprising 894 and 897 (Seafire) and 852 (Avenger) NAS while aircraft from Nabob and Trumpeter laid mines off the Norwegian coast. Fighters attacked Gossen Airfield and destroyed six Messerschmitt Bf 110 fighters on the ground and a radar station. On 22 August she took part in Operation Goodwood, a series of strikes against Tirpitz in Kaa Fjord which damaged the battleship but failed to inflict fatal damage.
Operation Divan, intended strikes on targets north of the Lofoten Islands in September, had to be cancelled because of bad weather.
In November 1944 Indefatigable was allocated to the new BPF, and she sailed from Portsmouth on 19 November with an air group made up with 24 Naval Fighter Wing comprising 887 and 894 (Seafire) NAS, 1770 (Firefly) and 820 (Avenger) NAS. She arrived in Colombo on 10 December, joined 1 ACS and worked-up before taking part in Operation Lentil, a strike against the oil refinery at Pangkalan Brandan in Sumatra in company with Victorious. On 16 January 1945 she sailed with the BPF for Operation Meridian, strikes against the oil refineries at Pladjoe and Songei Gerong near Palembang in Sumatra. In both strikes 24 Wing was limited to providing CAP over the fleet, but the Avengers and Fireflies joined in the striking forces. In Meridian II on 29 January Seafires destroyed five out of seven Kawasaki Ki-48 ‘Lily’ bombers that attacked the fleet; a Corsair from Victorious and a
Hellcat from Indomitable splashed the other two. Indefatigable arrived in Sydney on 10 February together with the bulk of the BPF to prepare for operations against the Japanese in the Pacific.
On 15 March 1945 she concentrated with the BPF, now designated Task Force 57 in the USN system, and prepared for Operation Iceberg, supporting the Fifth Fleet’s left flank during the amphibious landings in Okinawa. Strikes against airfields in the Sakishima Islands were sustained to prevent Japanese aircraft staging through them to attack American shipping off the invasion beaches.
Operations started after a refuelling stop at Ulithi Atoll at the end of March. On 25 March Indefatigable received two replacement Seafires and a Firefly from the replenishment carrier Striker while the fleet refuelled at sea. Back in action on 26 March, deck movement caused some strike sorties to be cancelled and caused a number of deck landing accidents involving Seafires, and a day later two Seafires collided while forming up after take-off; both pilots were lost.
On 1 April 1945 Indefatigable was the first of the BPF carriers to be hit by a kamikaze aircraft. It hit at the base of the island, killing twenty-one men and wounding a further twenty-seven, but the flight deck was operable after only thirty minutes and the ship was ‘reasonably operational’ that evening.
On 5 April she received three Seafires, an Avenger and a Firefly from Striker, but when she resumed strikes Seafires continued to be damaged in deck landing accidents at a rate beyond that at which they could be replaced, and the number available continued to decline. On 9 April one Seafire, one Avenger and one Firefly were flown on from Striker, but a day later a Seafire crashed into the after- barrier stanchion, destroying both itself and the stanchion. A temporary replacement was rigged by sunset to keep her in action. By this stage Indefatigable was short of seventeen Seafires and a Firefly, and a further eleven Seafires, two Fireflies and two Avengers were damaged beyond the ability of ship’s staff to repair. On 16 April a Seafire bounced over two barriers and crashed into the forward deck park, Fly 1, killing a maintenance rating and writing off both itself and an Avenger. It is hardly surprising that 1 ACS complained that the Seafire was totally unsuited to Pacific operations, and there was concern that a second Seafire-equipped carrier was due to join the fleet. On 7 June Indefatigable returned to Sydney with the BPF for an operational turn-round. Machinery defects had to be rectified, and her departure was delayed until after the other three carriers had sailed for operations off the Japanese mainland.
Indefatigable finally sailed from Sydney on 12 July 1945, and made a high-speed passage to the operational area. Improvements had been made to the Seafires, including the procurement of larger drop-tanks which gave them the radius of action to escort Avenger strikes and even carry out interdiction operations of their own with bombs. A concentrated period of pilot training had also reduced the number of deck landing incidents by the time she returned to action. By August she was in action with the BPF, which formed TF 37 of the Anglo/American Third fleet, and on 9 August her aircraft flew sweeps over airfields on the Japanese mainland which resulted in the destruction of over fifty enemy aircraft for the loss of seven RN aircraft and five pilots. The last day of planned operations before the BPF was due to withdraw to Australia to prepare for Operation Olympic, the Allied invasion of Japan in the autumn, was 10 August. However, with the unforeseen collapse of Japan and the imminent surrender, a token BPF force including Indefatigable, two battleships, cruisers and destroyers remained with the Third Fleet to be ‘in at the finish’. The force came under the direct orders of Admiral McCain USN and formed part of TF 38. On 13 August strikes were carried out in the Tokyo area, after which the carriers refuelled at sea.