HMS Onyx (S21): The Only Conventional Submarine to Fight in the Falklands

Built at Birkenhead

HMS Onyx was built by Cammell Laird, laid down on 16 November 1964, launched on 18 August 1966 and commissioned on 20 November 1967, an Oberon-class submarine displacing 1,610 tons standard, fitted with Type 186 and Type 187 sonars alongside I-band radar, armed with eight 21-inch torpedo tubes and crewed by 68 officers and ratings.

She is the second boat to be given the name in five years, and the first one never flew the White Ensign at all. An Oberon laid down at Chatham as HMS Onyx was handed over to Canada partway through building and completed as HMCS Ojibwa, so the name went back into the pool and was issued again to this hull at Birkenhead. What became of Ojibwa and her two Canadian sisters is told in HMS Osiris. It is a small piece of administrative tidying that put the name on the one Oberon that would end up fighting a war.

The Only Conventional Boat in the Falklands

Onyx holds the distinctive honour of being the only non-nuclear submarine of the Royal Navy to take part in the Falklands War, a demanding deployment for a diesel-electric boat operating alongside the nuclear-powered submarines that otherwise dominated the campaign.

The reason a diesel boat was wanted is the same reason her deployment was so hard. A nuclear submarine has effectively unlimited power and can cross an ocean submerged at twenty-odd knots without surfacing once, which is why HMS Conqueror and HMS Splendid were in the South Atlantic within a fortnight. Onyx could not do that. She had to run on the surface or at snort depth on her diesels for most of the passage, at a fraction of the speed, and it took her a very long time.

She sailed from Gosport on 26 April 1982 and did not reach the operating area until 31 May, by which time the landings at San Carlos had already happened and the war had a fortnight left to run. What she offered in exchange for that slowness was the thing the nuclear boats could not offer: she was smaller, she could work in shallow water close inshore, and she could sit on the bottom or hang almost motionless with everything shut down, which a reactor plant that must keep circulating coolant cannot do. For putting men ashore on a hostile coast, that is the boat you want.

The passage itself was a trial. One of her diesels over-sped on the way south and a large number of cylinder heads had to be changed at Ascension Island, and her executive officer, who was also a ship's diver, went over the side to repair damage to an external fuel tank, working submerged in water thick with her own leaked oil. She picked up her SAS and SBS passengers at Ascension in the middle of all that and carried on.

She carried out reconnaissance photography and landed Special Boat Service and Special Air Service special forces teams in shallow waters that the larger nuclear boats could not safely approach, exactly the kind of close-inshore work her smaller size made her uniquely suited for.

Getting them off and getting them back was the worst of it. Special forces insertion from a submarine means surfacing, or coming shallow, on an enemy coast at night and putting men into inflatable boats in whatever weather the South Atlantic is offering in late autumn, then returning days later to a rendezvous they may or may not have reached. Her crew have described not knowing, on the way back in, whether the men they collected would be the same men they had dropped. At least one operation, an attack on an airfield on the Argentine mainland, was cancelled while she was carrying the team for it. HMS Otus would do very similar work in the Gulf a decade later.

She suffered bow damage during these operations, the cause disputed between an uncharted underwater pinnacle and an Argentine air attack, but continued her mission regardless.

The likeliest explanation has an excellent detail behind it. The charts available for those inshore waters were, in large part, the work of Captain James Cook, surveyed more than two hundred years earlier and never comprehensively redone, because until April 1982 nobody had much reason to spend money surveying the coastline of the Falkland Islands to modern standards. Onyx, feeling her way in close to land a raiding party, hit a rock that Cook had missed. Her crew put it exactly that way afterwards. She carried the dent for the rest of the deployment and kept working.

A Memorably Irreverent Motto

Onyx's ship's motto, Taurus excreta cerebrum vincit, translates rather bluntly as 'bullshit conquers brains', a wonderfully irreverent touch of submariners' humour for a boat that had, in reality, performed some of the most dangerous and demanding work of the entire Falklands campaign.

It is worth saying that no heraldry committee at the Admiralty ever signed that off. It is the crew's own, the sort of thing a ship's company adopts and paints somewhere an officer will not immediately see it, and the Latin is a joke rather than a translation anybody laboured over. Given that she was the slowest boat sent to the war, arrived after the landings, spent the campaign creeping about inshore on charts drawn by an eighteenth century explorer and came home with a dented bow, a motto about improvisation triumphing over cleverness seems about right.

A Museum That Could Not Last

HMS Onyx was decommissioned in 1991 and put on display at Birkenhead before being purchased in 2006 for a planned heritage museum in Barrow-in-Furness. When that museum ran into financial difficulties, Onyx was towed to Rosneath in Scotland in April 2014 and scrapped later that year, a rather deflating end for a submarine whose Falklands service had been notably remarkable.

Before any of that she had to get home, and she did it the hard way. She did not start north until the end of July, more than six weeks after the Argentine surrender, and a main engine gave trouble on the way so that she made the passage on one. Coming in at the end of it her windlass seized and the anchor and cable had to be let go and abandoned on the seabed. She tied up at Gosport on 18 August 1982, the last British warship to return home from the Falklands, after 117 days away and twenty thousand miles, roughly half of them submerged.

Which makes the ending harder to take. She was saved once, opened to the public at Birkenhead, sold in 2006 to a businessman who wanted her as the centrepiece of a submarine heritage centre at Barrow, and moved there as a gift to the town. When the venture ran out of money she became an asset on a liquidator's list, was towed to Rosneath on the Clyde in April 2014 and cut up that September. The only conventional submarine Britain sent to the Falklands, and the last ship home from that war, was scrapped because a museum could not balance its books. HMS Ocelot survived the same period only because she sits in a national museum rather than on somebody's balance sheet.