 Unicorn at a Japanese port (probablySasebo) | |
| History | |
|---|---|
 United Kingdom | |
| Name | Unicorn |
| Namesake | Unicorn |
| Ordered | 14 April 1939 |
| Builder | Harland and Wolff,Belfast,Northern Ireland |
| Cost | £2,531,000 |
| Yard number | 1031[1] |
| Laid down | 26 June 1939 |
| Launched | 20 November 1941 |
| Completed | 12 March 1943[1] |
| Decommissioned | January 1946 |
| Recommissioned | Mid-1949 |
| Decommissioned | 17 November 1953 |
| Identification | Pennant number: I72 |
| Fate | Scrapped, 15 June 1959 |
| General characteristics (as completed) | |
| Type | Maintenanceaircraft carrier |
| Displacement | |
| Length | 640 ft (195.1 m) |
| Beam | 90 ft 3 in (27.51 m) |
| Draught | 23 ft (7.0 m) (deep load) |
| Installed power |
|
| Propulsion | 2 × shafts; 2 ×gearedsteam turbine sets |
| Speed | 24knots (44 km/h; 28 mph) |
| Range | 7,000 nmi (13,000 km; 8,100 mi) at 13.5 knots (25.0 km/h; 15.5 mph) |
| Complement | 1,200 (wartime) |
| Sensors and processing systems |
|
| Armament |
|
| Armour |
|
| Aircraft carried | Approximately 33 (operational use) |
HMSUnicorn was an aircraft repair ship andlight aircraft carrier built for theRoyal Navy in the late 1930s. She was completed duringWorld War II and provided air cover over theamphibious landing at Salerno, Italy, in September 1943. The ship was transferred to theEastern Fleet in the Indian Ocean at the end of the year.Unicorn supported the aircraft carriers of the fleet on their operations until theBritish Pacific Fleet (BPF) was formed in November 1944. She was transferred to Australia in early 1945 to support the BPF's operations duringOperation Iceberg, the Allied invasion ofOkinawa in May. To shorten the time required to replenish the BPF's carriers, the ship was based in theAdmiralty Islands and in thePhilippine Islands until the Japanese surrender in August.Unicorn was decommissioned and placed inreserve when she returned to the UK in January 1946.
The ship was recommissioned in 1949 to support the light carrier of theFar East Fleet, as the Eastern Fleet had been redesignated after the end of World War II. She was unloading aircraft and equipment inSingapore in June 1950 when theKorean War began. She spent most of the war ferrying aircraft, troops, stores and equipment in support ofCommonwealth operations in Korea.Unicorn supported other carriers during operations in Korea, but she became the only aircraft carrier to conduct a shore bombardment with her guns during wartime when she attacked North Korean observers on the coast during the war.[2] The ship returned to the UK after the end of the war and was again placed in reserve. She was listed for disposal in 1958 and sold forscrap in 1959.
TheAbyssinia Crisis of 1934–35 demonstrated to theAdmiralty that it needed adepot ship to support the aircraft carriers in active service, just likesubmarine anddestroyer tenders supported those types. Such a ship would be able to perform a wider range of aircraft repair and maintenance tasks than aircraft carriers and on the full range of aircraft operated by the Royal Navy, includingamphibians. AdmiralReginald Henderson,Controller of the Navy was instrumental for gaining approval for the ship and ensuring that she had a complete flight deck that would allow her to land, service and launch aircraft on active operations.[3] She was the first ship built in any navy that could "carry out the full range of aircraft maintenance and repair work in addition to the ability to operate aircraft from the flight deck".[4] In practice,Unicorn proved the value of the concept and two similar support ships,Perseus andPioneer were converted into aircraft maintenance ships by modifying light aircraft carriers still under construction.[5]
Unicorn had anoverall length of 640 feet (195.1 m), abeam of 90 feet 3 inches (27.5 m), and adraught of 23 feet (7.0 m) atdeep load. She was somewhat overweight as completed and displaced 16,510 long tons (16,770 t) atstandard load rather than her designed 14,750 long tons (14,990 t).[6] Each of the ship's two sets ofParsons gearedsteam turbines drove one 15-foot (4.6 m) propeller.[7] Steam was supplied by six Admiraltythree-drumwater-tube boilers operating at a pressure of 400 psi (2,758 kPa; 28 kgf/cm2). The turbines were designed for a total of 40,000shaft horsepower (30,000 kW) and gaveUnicorn a speed of 24knots (44 km/h; 28 mph).[6] The ship carried 3,000 long tons (3,000 t) offuel oil which gave her a range of 7,000nautical miles (13,000 km; 8,100 mi) at 13.5 knots (25.0 km/h; 15.5 mph).[7]
In order to land aircraft aboard,Unicorn was designed with a full-length, 600-foot (180 m)-longflight deck witharresting gear. She was also fitted with acatapult capable of launching a 14,000-pound (6,400 kg) aircraft to a speed of 66 knots (122 km/h; 76 mph).[8] The ship had twohangars, each 16 feet 6 inches (5.03 m) high. The upper hangar was 324ft by 65ft, and the lower 360ft by 62ft. Aircraft were transported between the hangars and the flight deck by twoaircraft lifts (elevators); the forward lift measured 33 by 45 feet (10.1 m × 13.7 m) and the rear one 24 by 46 feet (7.3 m × 14.0 m).Unicorn could carry about 36 operational aircraft. Bulkpetrol storage consisted of 36,500 imperial gallons (166,000 L; 43,800 US gal).[9] During wartime, the ship's crew totaled 1200.[10] The ship carried a self-propelledlighter under the rear of the flight deck to allow unflyable aircraft to be transferred between ships or to shore facilities. This lighter was lowered flush with the upper hangar deck so that an aircraft could be rolled onto it or an aircraft could be lifted onto it once the lighter was in the water.[11]
Unicorn was armed with four twin mounts for the 45-calibreQF 4-inch Mk XVIdual purpose gun.[6] This mounting could elevate from −10 to +80°. The Mk XVI gun fired about 12 35-pound (16 kg)high-explosive shells per minute at a muzzle velocity of 2,660 ft/s (810 m/s). Against surface targets it had a range of 19,850 yards (18,150 m) and a maximum ceiling of 39,000 ft (12,000 m), but an effective anti-aircraft range of much less.[12] She was also equipped with four quadruple mounts for the 40-millimetre (1.6 in)QF 2-pounder Mk VIII gun ("pom-pom").[10] These gun mounts could depress to −10° and elevate to a maximum of +80°. The Mk VIII 2-pounder gun fired a 40-millimetre (1.6 in) 0.91-pound (0.41 kg) shell at a muzzle velocity of 1,920 ft/s (590 m/s) to a distance of 3,800 yards (3,500 m). The gun's rate of fire was approximately 96–98 rounds per minute.[13] Close-range air defence was provided by twelve20 mm Oerlikonautocannon, in two twin mounts and eight single ones.[6] The Oerlikon fired a 0.272-pound (0.123 kg) shell at a muzzle velocity of 2,750 ft/s (840 m/s). It had a rate of fire of 465–480 rounds per minute and a maximum range of 4,800 yards (4,400 m).[14]
The ship was equipped with twoHACS (High Angle Control System)directors on herisland and each "pom-pom" mount had its own director as well.[6]Unicorn was the first ship to mount aType 281Bearly-warning radar,[15] and each HACS director was fitted with aType 285 gunnery radar.[6]
Unicorn was ordered on 14 April 1939, andlaid down atHarland and Wolff inBelfast,Northern Ireland on 29 June. Her construction was delayed several times in favour of higher priority projects and she was notlaunched until 20 November 1941. The ship was completed on 12 March 1943.[6] In order to accelerate the ship's completion, the Admiralty decided in 1942 that she would not be equipped with her full suite of maintenance and repair equipment.[16] Excluding her armament,Unicorn cost £2,531,000.[7][Note 1]
Whilstworking up,818 and824 Squadrons flew aboard in April 1943. 818 Squadron had nineFairey Swordfishtorpedo bombers and 824 Squadron had six.887 Squadron, with nineSupermarine Seafire IIC fighters was also embarked during this time.[18] In late May,Unicorn escorted Convoy MKF 15 toGibraltar while carrying a number ofRoyal Air ForceBristol Beaufighters that she off-loaded there. She escorted the returning convoy back to theClyde in early June. Together with the aircraft carrierIllustrious, the ship made a sweep towards the Norwegian coast as part ofOperation Governor, a diversion for theAllied landings in Sicily in early July.[19] For this operation, 887 Squadron was replaced by800 Squadron withHawker Sea Hurricanes.[20]
Unicorn was assigned toForce V, a flotilla of British carriers, commanded by AdmiralPhilip Vian, intended to provide air cover to Operation Avalanche, theAllied landings at Salerno. In preparation for this mission, the ship disembarked all of her Swordfish, except for a small detachment of three from 818 Squadron for self-defence, and the Sea Hurricanes of 800 Squadron. They were replaced by Seafires of809 and897 Squadrons. Each of the Seafire squadrons had 10 aircraft, for a total of 33.[21]Unicorn joined the escort carriers of Force V in August at Gibraltar before they moved forward to the Central Mediterranean for intensive training prior to the commencement of the amphibious landing on 9 September.[22]
The ship's Seafires flew 75sorties on the first day of operations and 60 on 10 September, but the Seafire was not well suited to carrier landings in low wind conditions and many were damaged in landing accidents. 44 sorties were flown on 11 September and only 18 on 12 September, even thoughUnicorn's mechanics had managed to repair ten Seafires over the previous night. The fighter shortage grew so acute during the operation that fighters from the carriersIllustrious andFormidable, intended to provide distant cover against an attempt by the Italian fleet to interfere with the invasion, staged forward toUnicorn in order to provide air cover over the landings.[23] By 12 September, the situation had improved so that 887 Squadron was able to fly off six Seafires to a temporary airfield ashore.[21]
The ship returned to the UK on 20 September with a full load of damaged Seafires, in addition to her own aircraft, that were off-loaded atGlasgow to be repaired. Afterwards, she was refitted by her builders and reconfigured for her designed role as an aircraft repair ship.[24]
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At the end of December 1943,Unicorn joinedIllustrious, thebattlecruiserRenown and the battleshipsQueen Elizabeth andValiant, the other reinforcements for the Eastern Fleet.[25] Only four Swordfish from 818 Squadron were carried aboard at this time.[26] The ship delivered a consignment of aircraft to Royal Navy Air StationCochin, India, on 27 January 1944 before arriving atTrincomalee,Ceylon on 2 February. In addition to her repair duties, the ship was often used for deck-landing practice. She was given a brief refit inBombay during May.[25] On 23 August, 818 Squadron was transferred toAtheling and later disbanded. On 7 November,817 Squadron flew aboard to provide anti-submarine protection with itsFairey Barracudas[27] asUnicorn was ordered toDurban, South Africa. There she was to be modified with separate workshops and additional equipment to accommodate American engines which used differentscrew threads and electrical fittings.[28]
That same month,Unicorn was transferred to the newly formed BPF. She left Durban on 1 January 1945 and arrived atColombo, Ceylon where she conducted deck-landing practice for pilots new to the BPF. The ship loaded 82 aircraft and 120 engines later in the month for transport to Australia, emptying the available stocks of the Eastern Fleet, and departed for Sydney on 29 January.Unicorn arrived on 12 February and disembarked her stored aircraft. She sailed forManus Island, in the Admiralty Islands, on 28 February to support the BPF's training before the opening stages ofOperation Iceberg. The ship arrived atSan Pedro Bay, Philippines on 27 March which was to serve as the BPF's intermediate replenishment base while it supported Operation Iceberg.[29]
The BPF was tasked to attack Japanese airfields in theSakishima Islands andFormosa before and during the early stages of the invasion of Okinawa.Unicorn was primarily engaged in preparing aircraft for issue to the operational squadrons aboard the fleet carriers during this time,[30] rather than repair them, but she did repair, modify or service 105 aircraft in March–May 1945. The ship sailed for Australia on 22 May and arrived in Sydney on 1 June. She sailed for Brisbane on 6 June to have her bottom cleaned at theCairncross Dockyard and to load more replacement aircraft.Unicorn arrived at Manus on 22 July to prepare foroperations off Japan. She was still there whenJapan surrendered on 15 August. The ship began to ferry aircraft, equipment and men back to Australia after the surrender, a task which ended on 6 November, when she arrived at Sydney.Unicorn departed for home in December 1945 and arrived inPlymouth in January 1946. She was decommissioned and placed in reserve.[31]
In 1949,Unicorn was reactivated for service in the Far East, in support of the carrierTriumph. She sailed fromHMNB Devonport on 22 September with a cargo of Seafires andFireflies. When theKorean War broke out in June 1950, the ship was disembarking aircraft, equipment and her maintenance personnel atRAF Sembawang, Singapore in preparation to return home and then to reserve. The Admiralty ordered her to be used as a replenishment carrier to ferry replacement aircraft and supplies to the Royal Navy and Commonwealth aircraft carriers operating in Korean waters.Unicorn left Singapore on 11 July and arrived atSasebo, Japan, on 20 July and transferred seven Seafires and five Fireflies toTriumph. In August, the ship ferried the 1st Battalion of theMiddlesex Regiment and the Headquarters of the27th Brigade from Hong Kong toPusan, arriving on 29 August. She delivered supplies to Sasebo before returning to Singapore to begin a refit.[32]
Unicorn resumed her duties in December, carrying about 400 troops in addition to the usual aircraft, stores and equipment. She was used by pilots for deck-landing practice en route. In March, she ferried theGloster Meteor jet fighters ofNo. 77 Squadron RAAF toIwakuni, Japan. The ship remained there for the next three months so she could be used as anaccommodation ship. Afterwards,Unicorn resumed her role as a ferry carrier. Whilst transiting theShimonoseki Strait on 2 October, she destroyed the overhead power cables stretching betweenHonshu andKyushu as they were sagging lower than normal due to a heavy snowfall. On 21 November,Unicorn and the carrierWarrior exchanged crews at Singapore and the ship began a refit shortly afterwards. After her refit was completed on 20 January 1952, she returned to her ferry duties.[33] In April, she was "adopted" by the Middlesex Regiment (possibly one of only three ships to be honoured by an Army regiment).[34] During operations byOcean in July, the ship acted as a spare flight deck to allow for damaged aircraft to land without disrupting the strike operations. She arrived back at Singapore on 27 July to load more replacement aircraft, including Meteors, and sailed on 9 August for Japan. During September,Unicorn borrowed four ofOcean'sHawker Sea Fury fighters to fly combat air patrols over the fleet whilst the latter ship conducted strike operations. She was docked for maintenance in October, and embarked theFirst Sea Lord, AdmiralRhoderick McGrigor and the Commander-in-Chief, Far East Station for a tour of Commonwealth forces in Japan. At one point,Unicorn became the only aircraft carrier in history so far to conduct a shore bombardment during wartime when she engaged North Koreancoastwatchers at Chopekki Point.[35]
The ship returned to Singapore for another refit on 15 December and did not leave Singapore until 17 July 1953. On 26 July, en route for Japan,Unicorn received a distress call fromSS Inchkilda south of theWuqiu region in theTaiwan Strait, saying that she was under attack by pirates - 3 gunboats of theROCAnti-Communist National Salvation Army (ACNSA).[36][37] The carrier closed on the freighter's position at high speed and the pirates abandoned their prize whenUnicorn circled the freighter with all guns bearing at less than 3,000 yards (2,700 m). TheKorean Armistice Agreement came into effect the following day, but the ship accompaniedOcean on two patrols on 30 July and 25–29 August to monitor North Korean compliance with the terms of the armistice. She sailed for home on 15 October and arrived at Devonport on 17 November, where she returned to reserve.[38]
In 1951,Unicorn was considered for modernisation to make her capable of operating modern, heavier jet aircraft. This would have required fitting of asteam catapult, reinforcing her flight deck to handle heavier aircraft and moving and enlarging her forward lift to make room for the new catapult and larger aircraft. A newcrane would also have been necessary to handle the heavier aircraft. TheDirector of Naval Construction proposed to combine both of her hangars into a single one to eliminate problems with hangar height, but this was rejected because of the excessive cost. This reconstruction would have begun in July 1954, but the entire scheme was cancelled in November 1952 because providing existing carriers withangled flight decks was much more important.[39]
Unicorn was redesignated as a Ferry Carrier in June 1953.[40] The ship was reduced to extended reserve in March 1957 and placed on the disposal list in 1958.Unicorn was sold for scrap in June 1959 and arrived atDalmuir on 15 June to begin the process. Her hull was broken up atTroon in 1960.[41]
