HMS Unicorn (S43): The Last Boat Built at Cammell Laird for Sixteen Years

Built at Birkenhead

HMS Unicorn was laid down at Cammell Laird's Birkenhead yard on 13 March 1990, launched on 16 April 1992 and commissioned into the Royal Navy on 25 June 1993, an Upholder-class diesel-electric submarine.

She holds a distinctive place in shipbuilding history: she was the last vessel built at Cammell Laird until construction began on HMS Queen Elizabeth in June 2010, a gap of nearly seventeen years for one of Britain's most storied shipyards.

That gap is worth pausing on, because it is not a piece of trivia about a shipyard. Cammell Laird had been building ships on the Mersey since 1828. It built the Ark Royal that went to the Bismarck, and HMS Oberon class boats, and a great deal else besides. When Unicorn went down the slip, the yard ran out of orders and effectively stopped, and it did not build another ship until sections of the new carriers came along seventeen years later.

A submarine is a strange thing to be the last of. She was one of the most advanced conventional boats in the world, built by people who had been doing it for a hundred and sixty years, and the reward for finishing her was that everybody went home.

A Brief Royal Navy Career

Unicorn's operational service took her across the Mediterranean, east of Suez, the Gulf of Oman, and the Indian and Persian Gulfs, but her time in Royal Navy colours proved remarkably short.

The Best Conventional Submarine Britain Ever Built

It is worth saying plainly what was being thrown away, because "diesel-electric submarine" sounds like something left over from the war. The Upholders were the successors to the Oberons and they were a generation beyond them: a single-hulled, highly automated design with a crew of about forty-seven where an Oberon needed close to seventy, modern sonar, Tigerfish and later Spearfish torpedoes, and Sub-Harpoon. They were extremely quiet.

Quiet is the entire point of a conventional submarine and the one thing a nuclear boat can never quite manage, because a reactor has pumps that must keep running. A modern diesel boat sitting on her battery makes very nearly no noise at all. That is why almost every other navy in the world still operates them, and it is why the Upholders were genuinely desirable objects rather than surplus.

The name was chosen with some care too. The first HMS Upholder was the most successful British submarine of the Second World War, and giving her name to a new class in the 1980s was a statement of intent. The class lasted rather less well than the reputation it borrowed.

Caught up in the post-Cold War defence cuts that saw the entire Upholder class judged surplus to requirements, she was decommissioned at Devonport on 16 October 1994 after barely sixteen months of active service, a truly abrupt end for a submarine that had only just entered the fleet.

Sixteen months is worth measuring against something. She was laid down in March 1990 and commissioned in June 1993, so she took three years and three months to build and served for one year and four months. She spent roughly two and a half times as long being built as she ever spent in commission, and rather longer than that afterwards sitting at Devonport waiting for somebody to buy her.

And she was not idle in it, which makes it worse rather than better. In that single year she worked the Mediterranean, went east of Suez, and operated in the Gulf of Oman and the Persian Gulf. For a boat that had only just finished her trials that is a genuine operational deployment on the far side of the world, not a shakedown cruise. She proved she could do the job and was paid off almost immediately afterwards.

The decision behind it was not about her. The 1990s defence reviews took the view that the Royal Navy would operate nuclear submarines and nothing else, and once that was settled a brand new conventional boat was an orphan regardless of how good she was. The whole class went the same way, and with it the last of the skills and the last of the flotilla. HMS Opossum tells the end of that story from the other side, and the Royal Navy has not operated a conventional submarine since.

Whether it was the right call is still argued. What is not arguable is the timing: Britain spent the money, built four excellent submarines, and then decided it did not want the category. Unicorn is the clearest single illustration of it because she was the newest, and so she had the shortest career of the lot.

A Second Life in Canada

The British government offered Unicorn and her three sister boats to Canada in 1993, an offer finally accepted in 1998 under an arrangement that saw the four submarines leased to Canada for US$427 million, with provision for eventual sale at minimal further cost.

The phrase "minimal further cost" is doing a lot of work there. The agreement was finalised on 2 July 1998: Canada leased the four boats for US$427 million, spent something like a further US$98 million bringing them up to Canadian standards, and ran the lease for eight years. At the end of it the four submarines became Canadian property outright for one pound.

A pound. For four of the quietest conventional submarines in the world, one of which had been in commission for sixteen months and was effectively new. It was not quite the giveaway that sounds, since the lease payments and the modification bill were real money and Canada also took on the cost of boats that had been laid up for years. But the headline is the headline, and it is the sort of thing that gets asked about in Parliament.

Canada wanted them for good reasons. She has the longest coastline in the world, three oceans to watch and a defence budget that was never going to stretch to nuclear submarines. Four modern conventional boats at that price was, on paper, an excellent piece of business.

Delays caused by problems with piping welds slowed her reactivation, but Unicorn was formally handed over to the Canadian Forces on 6 August 2001, arriving in Canada on 19 October, and was finally commissioned as HMCS Windsor on 4 October 2003, beginning a new chapter in Royal Canadian Navy service under a new name and a new flag.

The reactivation was harder than either side expected. Boats that have been sitting alongside for years do not simply start again, and the piping welds were one problem among several across the class. HMS Unseen and HMS Ursula carry the fuller account of what the four went through, which was long, expensive and at times very public.

Windsor herself is still in service with the Royal Canadian Navy, and that is the ending worth noting. A submarine launched on the Mersey in 1992 and discarded by the navy that ordered her after sixteen months is, more than thirty years later, still a commissioned warship under another flag. The Royal Navy built something it turned out not to want, and somebody else has been getting the use of it ever since.