HMS Sovereign (S108): Forty-Nine Days Shadowing a Soviet Submarine

Barrow-Built

HMS Sovereign was built by Vickers Shipbuilding and Engineering Limited at Barrow-in-Furness, with construction beginning on 18 September 1970. She was launched on 17 February 1973 and commissioned on 11 July 1974, a Swiftsure-class fleet submarine built for exactly the kind of demanding, long-endurance Cold War work that would come to define her career.

She was the second of six Swiftsures, following HMS Swiftsure herself and preceding HMS Sceptre, HMS Superb, HMS Spartan and HMS Splendid. The class was the Royal Navy's answer to a specific problem: the first generation of British nuclear boats could go anywhere but were not quiet enough to sit still and listen in company with what they were listening to. The Swiftsures were shorter, fatter, deeper-diving and appreciably quieter, and they were built to get close to Soviet submarines and stay there. Everything that made Sovereign's career worth recording follows from that.

Breaking the Ice

As part of Operation Brisk, Sovereign surfaced through the Arctic ice on 21 October 1976 at a position roughly halfway between the Geographic North Pole and the northern tip of Ellesmere Island, a joint Royal Navy and Canadian Forces effort to evaluate navigation systems under some of the most extreme conditions a submarine crew could face.

Brisk was a good deal more than a navigation trial. She spent ten days operating under the ice cap, and much of that time was spent on geophysical survey work: running lines beneath the pack and recording the profile of its underside, which is data no ship on the surface can gather and which went to civilian scientists rather than to the Admiralty. A submarine is the only vehicle that can measure the bottom of the Arctic ice, and for a fortnight in 1976 the Royal Navy lent one to the people who wanted to know.

The surfacing itself was the difficult part and the reason the Canadians were involved. Coming up through pack ice means finding a polynya, a window of thin ice or open water in a sheet that may be many feet thick, locating it from below with upward-looking sonar, and then bringing several thousand tons of submarine vertically up through it without wrecking the fin or the masts. Sovereign's commanding officer hunted for one in the vicinity of the Pole before finding the spot she used. Overhead, aircraft of the Canadian Forces Maritime Proving and Evaluation Unit out of Summerside on Prince Edward Island photographed and imaged the whole thing with side-looking airborne radar and a laser profilometer, as part of their own long project on remote sensing over ice. The results were written up in the scientific literature, which is not something that usually happens to a submarine patrol.

She was not the first British boat under the ice and did not claim to be. HMS Grampus had spent three weeks up there in the winter of 1962 and 1963, coming home with her hull damaged, and HMS Dreadnought had surfaced at the North Pole itself in March 1971. What Brisk added was endurance and instrumentation rather than a first.

Shadowing the Soviets

Sovereign's most striking achievement came during Operation Agile Eagle, when on 6 October 1978, under Commander Richard Farnfield, she acquired contact with a Soviet Delta-class ballistic missile submarine in the Eastern Atlantic and remained in undetected contact with her quarry for a remarkable 49 days, precisely the sort of quiet, patient intelligence-gathering that rarely made headlines but mattered enormously to the strategic balance of the Cold War.

Forty-nine days needs unpacking, because "shadowing" makes it sound companionable. A Delta was a Soviet ballistic missile submarine, the direct equivalent of Britain's Polaris boats, carrying the weapons that would end the war in its first half hour. Trailing one means holding a position astern of her, close enough to keep her on sonar and far enough back that she cannot hear you, matching every alteration of course and speed she makes, including the violent unpredictable turns Soviet captains used specifically to catch anybody doing exactly this. It is done at a few knots in near silence, and the man on the sonar set cannot lose the trace even once, because a lost contact in the deep Atlantic is very often a contact lost for good.

Doing it for seven weeks without being detected has a hard strategic meaning. It says that in the event of war, that particular Soviet submarine would have been sunk before she could launch, and her crew would have had no idea it was coming. Multiply that across a fleet and you have the reason NATO invested so heavily in quiet hunter-killers: not to fight a nuclear war, but to make the other side's planners unable to promise their own government that the missiles would ever leave the tubes. The whole point of the exercise was that nothing happened, forty-nine days running.

A Long Working Life

Sovereign underwent a comprehensive refit through the mid-1990s and was rededicated in January 1997, before emergency repairs at Rosyth in June 1998 addressed a cracked tailshaft. She took part in Submarine Command Course training, known informally as Perisher, in June 1999, and joined the NATO exercise Linked Seas in May 2000.

The cracked tailshaft the following year sounds like a minor engineering note and is not. The tailshaft is the shaft that carries the power from the turbines out to the propeller, and it has to pass through the pressure hull to get there, which makes it one of the very few deliberate holes in the thing keeping the sea out. A crack in it is both a propulsion problem and, potentially, a flooding one, and it is not something that can be left until the next scheduled docking. Hence emergency repairs at Rosyth in June 1998, eighteen months after she had come out of a full refit.

Reactor difficulties in the early 2000s eventually caught up with her, and she was decommissioned in September 2006 after more than three decades of demanding service.

That is the sentence that ended most of the class. The Swiftsures had been built in the early 1970s and their reactor plant was the limiting factor: once the primary circuit of a boat of that age begins to give trouble, the choice is a refuelling and refit costing several hundred million pounds or an early retirement, and by the mid-2000s with the Astutes ordered there was only ever going to be one answer. Sovereign went in September 2006 after thirty-two years. Only HMS Sceptre was still running by then, and she lasted until 2010, the last of the six.

Her time as a Perisher platform in 1999 is worth a closing word, because it is a quiet kind of legacy. A boat that had trailed a Delta for seven weeks was, twenty years later, the classroom in which the next generation of submarine captains were failed or passed. What that course involves is set out in HMS Oracle. The skills Sovereign was built around went out of her and into the men who took her to sea.