HMS Unicorn (I72): The Only Carrier to Fight a Shore Battle With Her Own Guns

A Revolutionary Design

HMS Unicorn was ordered from Harland and Wolff in Belfast on 14 April 1939, laid down that June, and after wartime construction delays finally launched on 20 November 1941 and completed on 12 March 1943.

At 640 feet long with a full flight deck, two hangars, aircraft lifts and extensive repair workshops, she was the first ship in any navy able to carry out the complete range of aircraft maintenance and repair work while also operating aircraft in her own right, a remarkably pioneering concept in naval aviation support.

The Problem She Was Built to Solve

Revolutionary is the right word and it needs unpacking. In 1939 the Fleet Air Arm had a problem nobody had thought about very hard: what to do with a damaged aeroplane. A carrier could patch minor defects and change an engine at a pinch, and anything worse meant striking the aircraft below, carrying it to a base ashore and putting it into a workshop, which in the Indian Ocean or the Pacific might be several thousand miles away. Attrition, in other words, was permanent. A wing bent on landing took an aircraft out of the war.

Unicorn was the answer: a ship with two full hangars, aircraft lifts, machine shops, a foundry, coppersmiths, riggers, engine bays and a stock of spares, that could also fly her own aircraft off her own deck. She could take a wrecked Seafire aboard, rebuild it and hand it back. No navy had built one before, and the concept was sound enough that the Royal Navy kept using it, in one form or another, for the next thirty years.

She was, incidentally, a good-looking ship with an unusual profile: two hangars stacked gave her enormous freeboard, and the hull was so deep that she is sometimes mistaken in photographs for a much larger fleet carrier.

Seafires Over Salerno

After working up with naval air squadrons in spring 1943 and taking part in Operation Governor off Norway, Unicorn's main combat role of the war came during the Salerno landings that September, when her Seafire fighters flew air cover sorties for the amphibious assault, though the operation revealed the type's notorious fragility with many aircraft damaged on landing.

Force V, and the Calmest Sea in the Mediterranean

At Salerno she was not a repair ship at all; she was a fighting carrier, and the operation is a case study in how one weather condition can wreck an air group. Force V, under Rear-Admiral Philip Vian, was Unicorn and four escort carriers, put there to hold air cover over the beachhead until the airfields ashore could be captured, because Salerno was just beyond the range at which Sicily-based Spitfires could loiter. Force H gave up eight Seafires and eight Martlets to bring Unicorn's air group up to twenty-five aircraft, seventeen of them Seafires.

She reached the beaches on 9 September 1943 and flew her first sorties at a quarter past six that morning. Over the next four days Force V put up more than seven hundred sorties and Unicorn flew a hundred and ninety-eight of them. Not one of her aircraft was lost to the enemy.

What did the damage was the weather, and specifically the absence of any. The Bay of Salerno was flat calm for most of the operation. A carrier lands aircraft by steaming into wind fast enough that the aeroplane is moving slowly relative to the deck; with no natural wind and an escort carrier that could make eighteen knots on a good day, the closing speed on landing was far higher than anything the Seafire was designed for. The Seafire was a Spitfire with a hook, and the Spitfire had a narrow, delicate undercarriage designed for a grass airfield in Hampshire. They came aboard hard, and they broke.

Unicorn lost four Seafires in deck accidents and none to the Germans. Across Force V as a whole, an initial strength of something like a hundred and eighty Seafires had been reduced to about thirty serviceable aircraft by the end of the operation. It is one of the plainest lessons in naval aviation history: an aeroplane that cannot land reliably is not a naval aeroplane, however well it flies.

The Eastern Fleet and the Pacific

Unicorn went on to join the Eastern Fleet in the Indian Ocean, supporting carrier operations there before transferring to the newly formed British Pacific Fleet in late 1944, where she supported Operation Iceberg, the invasion of Okinawa, in 1945, putting her unique repair capabilities to good use keeping the fleet's aircraft flying through one of the war's most intense air campaigns.

Carrying the Army to Korea

Before the ferrying began she did something that rarely gets mentioned. In August 1950, with the Pusan perimeter contracting and the British government having promised troops, Unicorn embarked the 1st Battalion of the Middlesex Regiment and the 1st Battalion of the Argyll and Sutherland Highlanders at Hong Kong and carried them to Pusan. They were the first British ground troops of the Korean War, some fifteen hundred men landing to help hold a perimeter that was, at that point, roughly the size of a large English county and shrinking.

A Ferry Carrier at War in Korea

Recommissioned in 1949, Unicorn spent the Korean War ferrying replacement aircraft and supplies to Commonwealth carriers operating off Korea between 1950 and 1953, and in October 1952 achieved an unusual distinction, becoming the only aircraft carrier ever to conduct a shore bombardment with her own guns during wartime, engaging North Korean coastwatchers at Chopekki Point.

Then she settled into the run she is best known for: Singapore to Japan and back, six weeks a cycle, swapping worn-out aircraft for fresh ones at Sasebo, Kure and Iwakuni. One load gives the scale of it: thirty-two Fireflies, twenty-seven Seafires and a pair of Sea Otters, plus stores, in a single ship. The carriers she was feeding, Triumph, Theseus and Glory, could not have kept flying without her, and Triumph in particular ran out of aircraft precisely because the types she was operating had no supply chain left.

Sixteen Salvos at Chopekki Point

The bombardment is worth its own paragraph because of how faintly ridiculous the circumstances were. Chopekki Point is on the west coast of Korea, and the North Koreans had observers on it watching United Nations ships come and go and reporting what they saw. Somebody had to shoot at them. Unicorn happened to be there.

She had eight 4-inch guns in twin mountings, fitted for anti-aircraft work rather than shore bombardment, and she went in with the destroyers HMS Comus and HMS Cossack for company and fired sixteen salvos. Three of them are recorded as having found the target, which for a repair ship shooting at a hillside with anti-aircraft guns is a perfectly respectable afternoon. She was the first carrier to bombard anything in that war, and, as far as anybody has been able to establish, the only aircraft carrier of any navy to fight a shore action with her own guns.

She had distinguished company aboard about this period too: the First Sea Lord, Admiral Sir Rhoderick McGrigor, and the Commander-in-Chief of the Far East Station used her for a tour of Commonwealth forces in Japan.

Her last recorded drama was more typical of her trade. On 11 August 1953 two Sea Furies collided on her deck, and one of them went over the side on fire.

Broken Up at Troon

Returned to reserve in November 1953, HMS Unicorn was placed on the disposal list in 1958, sold for scrap in June 1959 and broken up at Troon in 1960, closing out the career of a ship whose original repair-carrier concept proved its worth from the beaches of Salerno to the coast of Korea.