HMS UNICORN a unique vessel

One ship, four roles In the late 1930s the Royal Navy began looking at providing afloat support facilities to allow sustained operations by its armoured fleet carriers.  The proposals for meeting these needs included assembling a collection of repair, maintenance and depot ships that could follow the fleet (the very concept that became the Fleet Train created for the British Pacific Fleet in late 1944) however this was a costly proposal involving several vessels. The UNICORN class aircraft repair and maintenance carrier was a compromise, one ship performing many roles. She was a fully functioning Light Fleet Aircraft Carrier, but outfitted as an aircraft Repair and Maintenance vessel, with the capability to operate as an aircraft Ferry Carrier and a Heavy Transport. She was designed with spacious double hangars intended to accommodate any type of aircraft in use by the RN at the time. Reserve aircraft were to be stored into the lower hangar, while the upper hangar would be the maintenance and repair area.  She could service floatplanes embarked via a unique stern hangar access, both hangars could be accessed through this portal which gave her a stern profile very distinctive from that of conventional carriers.

Ordered from Harland and Wolff, Belfast UNICORN was ordered from Harland and Wolff, Belfast, Northern Ireland on April 14th 1939 and her keel was laid down on June 29th that year. She was launched on November 20th 1941 but Work on the ship was delayed by resources and manpower being diverted to more priority builds and this led to the decision to complete her as an operational carrier first and complete her outfitting as repair carrier later.  She was commissioned as HMS UNICORN on January 14th 1943, Captain Q. D. Graham, CBE, DSO, RN in command; the 14th RN ship to bear this name.

Completed as a conventional carrier first She operated as a Fleet Carrier for the first seven months of her service; her first operational task was to ferry 18 RAF Beaufighters for delivery to Gibraltar. She then joined the Home Fleet for operation GOVERNOR, a failed attempt to lure TIRPITZ and other German heavy battleships out of harbour, her squadrons seeing no action. She was then allocated to Operation AVALANCHE for the Allied landings near the port of Salerno operating as part of Force 88 with the escort carriers ATTACKER, BATTLER, HUNTER, and STALKER. During eight days they launched a combined total of 713 sorties, providing more than half the allied air coverage over the beach head, UNICORN’s squadrons flew 198 sorties. On completion she returned to Belfast to complete her fitting out as a repair and maintenance carrier.

Completed as a repair & Maintenance Carrier On completion of her maintenance outfit she would no longer carry her own squadrons, the Air Operations Department was reduced to the minimum required to receive and despatch aircraft related to repair and maintenance. In her new role UNICORN was allocated to the Eastern Fleet in 1944 and operated as both a maintenance ship and Deck landing Training Carrier based at Trincomalee. After a refit in South Africa at the end of the year, to allow her to support new US aircraft types, she joined the British Pacific Fleet (BPF), arriving at Sydney in February 1945.     Her first task was to embark and deliver the vehicles, equipment and a small advance party of Maintenance Storage & Reserve Unit (MSR) 4 to the US Naval Air Station on Ponam Island in the Admiralty Islands. From there she proceeded to San Pedro Bay, Leyte, in the Philippines were she was to operate with the Fleet Train;   aviation afloat repair was provided by UNICORN together with the Aircraft Component Repair ship DEER SOUND and the Air Stores Issue Ship FORT COLVILLE. She was now part of a supply chain stretching from Australia to the Philippines and on to the replenishment areas where the BPF were fuelled and stored at sea and replacement aircraft were issued, ferried forward by escort carriers. She remained at Leyte until June supporting the BPF during operation ICEBERG, when the fleet and UNICORN returned to Australia for a major replenishment.

Reserve aircraft stowed in one of UNICORN's hangars, there are 3 Corsairs and 1 Firefly parked along the hangar wall.

UNICORN entered dry-dock for repairs before re-joining the Fleet Train on July 21st, this time operating off Pityilu Island in the Admiralty Islands in company with the new Maintenance Carrier PIONEER, DEER SOUND and Airt Store Issue Ships FORT COLVILLE and FORT LANGLEY. They were now supporting the BPF during operations against mainland Japan. She remained in the Admiralty Islands after the Japanese surrender, her heavy transport capability was then utilised to help evacuate RN personnel and equipment from Ponam and Pityilu Islands for return to Australia.  On completion of these duties she sailed from Sydney on November 24th 1945 for the UK.   She arrived at Devonport on January 16th 1946 and after unloading and destoring was transferred to the Reserve Fleet on the Tamar River. Since UNICORN left the UK in December, 1943, a total of 626 aircraft passed through the hands of the Air Repair Division, these included Albacore, Avenger, Barracuda, Corsair, Firefly, Fulmar, Hellcat, Martinet, Sea Hurricane, Seafire, Swordfish, Vengeance and Walrus aircraft. Additionally, the Department also handled 283 engines and power plants. 63 engines were installed in aircraft or power plants.

Reactivated for support of the Far East Fleet and the Korean War In 1948 she underwent a refit and in the summer of 1949 she was recommissioned for service with the Far East Fleet. Her deployment was necessary as a result of the post war reduction in RN bases in the Far East; there were no longer any Air Repair Yards and only one Naval Air station remained semi-operational, RNAS Sembawang at Singapore. The Light Fleet carrier TRIUMPH was to begin strike operations against Malayan Insurgents in October and required aviation support.  UNICORN embarked 32 Firefly, 27 Seafire and 2 Sea Otter aircraft plus additional stores and equipment for both RNAS Sembawang and HMS TRIUMPH before sailing from the UK on October 1st. While on passage through the Suez Canal on October 6th she ran aground and blocked north bound Suez Canal traffic for 14 Hours before being refloated.   Having accompanied TRIUMPH and other ships of the Far East Fleet on a visit to Kure, Japan she was preparing to return to the UK in June 1950 when the Korean War started.  Her role was to change again, the majority of her Air Engineering Department was put ashore to RNAS Sembawang and UNICORN would be used primarily as a ferry/replenishment carrier transporting aircraft and supplies to the Royal Navy and Commonwealth aircraft carriers operating in Korean waters.   She supported the carriers GLORY, OCEAN. SYDNEY, THESEUS and TRIUMPH over the next three years, operating between Singapore and Japan, calling at Hong Kong on both the inbound and outbound voyages. With stops at Kure, Sasebo and Iwakuni where a small Aircraft Holding Unit was established in June 1951 to keep a ready issue stock for use when UNICORN was away or under refit.

UNICORN (left) and OCEAN alongside at Kure, Japan c. September 6th 1952. The two carriers had just returned from the operational area where UNICORN had provided CAP sorties and a spare deck.

In addition to carrying troops, stores and aircraft she also provided a deck for training replacement pilots prior to their joining the on station carrier and accompanied OCEAN on patrol on several occasions operating as a spare deck during strike operations and carrying four Sea Fury to provide Combat Air Patrols. She also carried out a rare Carrier bombardment using her Twin QF 4-inch Mk XVI guns against targets on Chopekki Point. The armistice treaty ending hostilities was signed in July 1953 and UNICORN returned home in October of that year to refit before being returned to the reserve fleet.  Commonwealth operations off Korea ended on May 4th 1954 when HMAS SYDNEY completed her final tour: she was not relieved by another carrier.

An uncertain future Plans were considered for her modernisation to operate jets but were cancelled as being too costly, the job requiring the strengthening of the fight deck, the addition of an angled deck and consolidating the upper and lower hangars into one. She was redesignated as a ferry carrier and given the pennant number A195 but was never called out of reserve. She was scrapped in 1960. She was the only UNICORN Class vessel ordered, they were too expensive. Towards the end of the Second World war she was joined by 2 Colossus Class light Fleet Carriers, PERSEUS & PIONEER converted during construction to be aircraft maintenance ships; neither were capable of operating aircraft, they were completed without flight deck equipment, all airframes were embarked from lighter, or from a jetty, by crane. Our account of the service history of HMS UNICORN is our latest addition to the site.