The Nairana-class escort carrier () was a British-built class of three escort carriers. They were constructed one each in England, Scotland and Northern Ireland to the same basic design during the Second World War for service with the Royal Navy.
Converted from merchant ships, they were only able to accommodate a composite squadron of about 15–20 aircraft. Their armaments were mainly anti-aircraft weapons, with one twin 4 inch Dual Purpose, Anti Aircraft gun. One of the class, Campania, was the first British carrier to be fitted with an Action Information Organisation (AIO) and a Type 277 radar able to detect low-level aircraft.
Once completed the first carrier did not take part in active service until January 1944, but all three served as convoy escorts during the final year of the war. They had some success during their patrols, and anti-submarine Fairey Swordfish flying from their decks sank and damaged some German U-boats and their fighters succeeded in shooting down German long-range reconnaissance aircraft.
Design and description The Nairana-class escort carriers were a class of three escort carriers built for the Royal Navy during the Second World War.Cocker (2008), pp.76–78 Escort carriers were designed to protect convoys of merchant ships from U-boat and aircraft attack.Poolman (1972), p.155. Following the successful conversion and operation of HMS Activity, the Admiralty decided to take over three more merchant ships while they were still under construction and convert them into escort carriers.Poolman (1972), p.111. The three ships chosen were being built at three different shipyards around the United Kingdom, Harland and Wolff in Northern Ireland, Swan Hunter in England and John Brown & Company in Scotland. The prototype was built by John Brown who supplied the other two companies with copies of the plans. The three ships were supposed to be identical but in reality they were all slightly different.
Nairana built by John Brown was launched on 20 May 1943 and completed on 12 December 1943.Poolman (1972), pp.111–112. She had a complement of 728 men and displaced . Her other dimensions were a length of , a beam of and a draught of .Cocker (2008), p.77. Her aircraft facilities included a flight deck, a hangar by , eight arrestor wires and an aircraft lift by .
Vindex built by Swan Hunter was launched on 4 May 1943 and completed on 3 December 1943. She had a complement of 700 men and displaced . Her other dimensions were a length of , a beam of and a draught of . Her aircraft and her aircraft facilities included a flight deck, a hangar by , six arrestor wires and an aircraft lift by .
Campania built by Harland and Wolff was launched on 17 June 1943 and completed on 9 February 1944. She had a complement of 700 men and displaced . Her other dimensions were a length of , a beam of and a draught of . Her aircraft and her aircraft facilities included a flight deck, a hangar by , six arrestor wires and an aircraft lift by .Cocker (2008), p.76.
Common to all three ships was a traditional rivetted hull, steel flight decks and a closed hangar.Poolman (1972), p.112. They had the same propulsion provided by diesel engines connected to two shafts giving 11,000 brake horsepower (BHP), which could propel the ship at . Their armaments concentrated on anti-aircraft (AA) defence and comprised two 4 inch Dual Purpose, AA guns on a twin mount, sixteen 20 mm anti-aircraft cannons on eight twin mounts and sixteen 2 Pounder Pom Pom on four quadruple mounts. Aircraft assigned were either anti-submarine or fighter aircraft, which could be made up of a mixture of the Hawker Sea Hurricane, Grumman Wildcat, Fairey Fulmar or Fairey Swordfish.Cocker (2008), p.80. The exact composition of the embarked squadrons depended upon the mission. Some squadrons were composite squadrons for convoy defence and would be equipped with anti-submarine and fighter aircraft,Poolman(1972), p.98. while other squadrons working in a strike carrier role would only be equipped with fighter aircraft.Morison (2002), p.342.
Service history
HMS Nairana
Vindex and Nairana were both commissioned within days of each other in December 1943, and moved to Gourock for working up.Poolman (1972), p.114. Nairana with 835 Naval Air Squadron Fleet Air Arm on board commenced flying exercises with HMS Activity on 27 January 1944. Both carriers left the River Clyde on 29 January with the 2nd Escort Group under the command of Captain Frederic John Walker. They were to form a "hunter killer group" in the waters west of Ireland, providing cover for two southbound convoys OS 66 and KMS 70. Weather conditions had prohibited flying until 31 January. With clearer weather Nairana turned into the wind to send off her first anti-submarine patrol. At the same time Wild Goose reported contact with a submerged U-boat on her ASDIC. Warning Nairana that she had just turned into danger, the carrier took avoiding action. The U-boat U-592 was sunk by Wild Goose and Walker's own ship Starling, while a Fairey Swordfish from Nairana circled the area.Poolman (1972), p.115.
By this stage of the war the Royal Navy had enough escort carriers available not only to double them up on a convoy escort but to permanently detach one to work with a "hunter killer group" operating outside the convoy system. The 2nd Escort Group still under the command of Walker was the group chosen with Vindex as the carrier. As she would not be supported by another carrier Vindexs air group was formed from the experienced 825 Naval Air Squadron, with a complement of 12 Fairey Swordfish Mk IIs and six Sea Hurricanes IICs. Even though there were 12 Swordfish on board they had only eight crews so the Sea Hurricanes carried out some of the daylight anti-submarine patrols. The Sea Hurricanes had been fitted with four racks for the same RP-3 rockets used by the Swordfish to attack submarines.Poolman (1972), p.120.
Leaving Northern Ireland on 9 March 1944, 2nd Escort Group moved to the area believed to hold the highest concentration of U-boats. Over the night of 12 March Swordfish on patrol had 28 contacts on their airborne to surface vessel radar (ASV). Their first attack was unsuccessful dropping two depth charges that failed to explode believed to be caused by faulty safety clips, during the attack the rear gunner in the Swordfish was killed by the U-boats anti-aircraft guns. The depth charges dropped short on a second attack and failed to explode on a third attack during the same night.Poolman (1972), pp.120–121. On the night of 15 March two Swordfish got an ASV contact ahead of the escort group. Unable to see anything in the darkness they dropped flares and sea markers over the location. When the escort group arrived they picked up a contact on their ASDIC and the U-653 was sunk.Poolman (1972). p.121.
Weather conditions were still not perfect for flying and in the following days, one Swordfish returning from a night patrol landed in the sea alongside the carrier, the crew were reported missing believed killed. A pitching deck caused one Swordfish to crash into the sea on take-off and another Swordfish crashed into the sea on take-off when its engine failed. One Swordfish taking off clipped the island superstructure losing off both wing tips. The pilot managed to get the aircraft into the air circled around jettisoning his depth charges and landed again without mishap. Landing on the heaving deck was just as dangerous, two Sea Hurricanes and two Swordfish missed the arrestor wires and ended up crashing into the safety barriers. On 24 March 1944 a Swordfish with its engine shot up and crew injured attempted to land back on Vindex. It crash landed onto the flight deck coming to a stop from the end of the flight deck. Leaking petrol set the wreckage on fire, the crew were rescued but the fire exploded one of two depth charges stuck on their racks. A hole by was blown in the flight deck. After 16 days at sea Vindex returned to port. With two days flying lost because of the weather conditions, the Swordfish had amassed a creditable 275 flying hours and 122 deck landings by day and night. The Sea Hurricanes contributed another 47 hours flying and 39 deck landings.Poolman (1972), p.122.
At the end of May 1944 Nairana sailed with the 15th Escort Group. On board was 835 Naval Air Squadron equipped with nine Swordfish and six Sea Hurricanes. The Swordfish patrolled day and night and some contacts were made on the ASV. All the contact come to nothing, it is now known the older model ASV in Nairanas Swordfish could be detected by receivers on board U-boats. In May they escorted convoys SL 157 (Freetown to United Kingdom) with MKS 48 (Mediterranean to United Kingdom) and the next group SL 158 with MKS 49. From 25 May the convoys were located by German Junkers Ju 290 reconnaissance aircraft. On the 25 and the morning of 26 May they were driven off undamaged but one Sea Hurricane failed to pull out of a dive killing the pilot. Later the same day another two Ju 290s appeared one was shot down and the other was probably shot down. From 1946 to 1948, the ship was in service with the Royal Netherlands Navy as the HNLMS Karel Doorman (QH1).Poolman (1972), p.141–142.
HMS Vindex
With Vindex damaged and needing a refit and Campania still not commissioned, Nairana was the only ship of her class fit for sea on 1 April 1944. She left in the first week of April with the outbound convoys OS 72 (West Africa) and KMS 46 (Gibraltar).Poolman (1972), p.137. She still had 825 Naval Air Squadron on board but this time she was overloaded with 18 aircraft: 12 Swordfish Mk IIs and six Sea Hurricanes IIcs. At the end of the month Vindex joined the 5th Escort Group. On 6 May a patrolling Swordfish was contacted by two of the escort frigates, who reported they were in contact with a submerged U-boat. The frigates carried out a depth charge attack and forced U-765 to the surface. The Swordfish despite the anti-aircraft fire from the U-boat dropped two of its depth charges which broke the submarine in half.Poolman (1972), p.138.
Flying became dangerous in the heavy seas and poor visibility. One Sea Hurricane was damaged beyond repair after a serious crash into the safety barrier and another crashed into the sea with the loss of the pilot. The Swordfish crews fared little better. Three aircraft and one crew were lost during the same period. On 9 May Vindexs aircraft lift broke down with a burnt out motor. The crew had to resort to manually cranking the lift up and down, taking an hour to go each way. They eventually repaired the lift by moving the capstan motor through holes burned into the bulkheads.Poolman (1972), pp.139–140. During the second deployment by Vindex her aircraft flew over 400 sorties in 13 days. The strain on the aircrews began to show and only 35 per cent of the original Swordfish crews were still with the ship when they returned to port. It was during this second deployment that one of the ships officers, Sub-Lieutenant J.M. Morrison invented a blind landing system soon to be used on all the Royal Navy carriers. He modified an ASV radar set which was placed on the flight deck. The system employed the Air Directing Officer guiding aircraft to within of the ship. They could then be picked up on the ASV and brought in astern of the carrier at a height of .Poolman (1972), p.140.