HMS Devonshire (D02): The First Ship to Fire a Seaslug Missile, Sunk by a Submarine

The Build: Birkenhead

HMS Devonshire was built by Cammell Laird at Birkenhead, launched on 10 June 1960 and commissioned on 15 November 1962, the lead ship of the County-class and the first Batch 1 destroyer to enter service. She displaced 6,200 tons at full load, measured 520 feet in length with a beam of 54 feet, and could make 30 knots with a range of 3,500 nautical miles, carrying a complement of 471 officers and ratings. Her armament combined two twin 4.5-inch gun turrets, two Seacat close-range missile mounts, two sets of triple torpedo tubes and a single Wessex anti-submarine helicopter operating from her own hangar and flight deck, a genuinely well-rounded fit for a brand new class of ship.

That fit came at a price, and the price was the shape of the ship. A County was not a destroyer with a missile system added; she was a missile system with a ship built round it. Seaslug was very large, and it was stored disassembled: the magazine ran forward, holding the rounds nose to tail in two long lanes, and each missile had to be brought up and run the length of the ship through an internal tunnel, being checked over and having its wings and fins fitted as it went, before emerging onto the launcher right aft at the stern. That tunnel is why a County is 520 feet long and displaces more than some cruisers while being rated a destroyer, and it is why her machinery had to be split into two separate plants either side of it, one steam and one gas turbine, in the first British warship to use the combination.

She holds the properly significant distinction of being the first operational Royal Navy ship to fire the Seaslug missile, the Navy's first surface-to-air guided missile system and a major step forward in fleet air defence capability at the dawn of the guided missile era, conducting those firing trials that May, just months after entering service.

Seaslug itself is worth understanding, because it explains a good deal about where British missile technology was in 1962. It was a beam rider. The ship's radar painted a narrow beam at the target and the missile flew up the middle of it, correcting itself to stay in the centre, which is elegant, cheap in electronics, and entirely dependent on the ship holding the beam steady on the target for the whole flight. It also means the missile is only ever as accurate as the beam is narrow, which at long range is not very. And the beam degraded in bad weather. Seaslug worked, and it was a real advance on a gun, but it was arguably obsolescent on the day it entered service, and by the Falklands twenty years later the Counties were firing it at aircraft largely in the hope of putting them off.

A Global Early Career

Following her initial work-up, HMS Devonshire deployed to the Mediterranean, before sailing on to Bermuda and the United States and returning to Portsmouth by the end of 1962, an ambitious first deployment for so new a class of ship.

She went on to conduct patrol duties in the Persian Gulf and the Caribbean Sea, made repeated visits to Malta's Grand Harbour through the 1960s and 1970s as part of her regular Mediterranean rotations, and took part in the 1977 Silver Jubilee Fleet Review at Spithead, one of the great ceremonial gatherings of the postwar Royal Navy.

A Collision Near the Elbe

On 31 August 1966, HMS Devonshire collided with the tanker British Sovereign near the mouth of the River Elbe, though fortunately no one was injured aboard either ship, a reminder that even routine navigation close to busy European shipping lanes carried genuine risks.

Sunk as a Target

HMS Devonshire was decommissioned in 1978 as part of the defence cuts of that period, and spent six years laid up in Portsmouth before finding an unusual final role: serving as a target vessel for testing the Sea Eagle anti-ship missile and the Mark 24 Mod 2 Tigerfish torpedo, weapons that needed realistic targets to prove their effectiveness.

Devonshire nearly went the same way. When she paid off in 1978 she was offered straight to Egypt, and had that sale gone through she would very probably have followed her sisters into a long second career under another flag. It did not, and having found no buyer she sat at Portsmouth for six years while the fleet worked out what to do with her. That is the real reason she ended up on the wrong end of a torpedo: not a considered decision that the first British guided missile destroyer should be expended, but the ordinary bureaucratic outcome of a ship nobody wanted and a weapons programme that badly needed a hull to shoot at. The first of the class to fire a guided missile became the only one of the class to be destroyed by one.

What happened to the other seven puts her ending in context, because the class did not so much retire as emigrate. Eight Counties were built. Her Batch 1 sister HMS Hampshire (D06) went first, cannibalised for spares and scrapped in 1977; HMS Kent (D12) finished as a harbour training ship at Portsmouth and was not broken up until 1998; and HMS London (D16) was sold to Pakistan in 1982 and became PNS Babur. Then all four of the Batch 2 ships went to Chile, one after another, over six years.

The Chilean sequence is worth listing, because it is not often that a whole half-class ends up in one foreign navy. HMS Norfolk (D21) went in 1982 and became Capitan Prat, serving until 2008; HMS Antrim (D18) followed in 1984 as Almirante Cochrane and lasted until 2010; HMS Glamorgan (D19) went in 1986 as Almirante Latorre; and HMS Fife (D20) completed the set, sold in August 1987 and commissioned as Blanco Encalada in 1988 after a rebuild at Talcahuano. Two of those four had been in the South Atlantic in 1982, one of them flagship for the recapture of South Georgia and the other hit by an Exocet off Stanley, and both were in Chilean service inside four years of it. Several of them went on serving into the twenty-first century, which means the design outlasted the Royal Navy's interest in it by a quarter of a century.

The Tigerfish trial is the part of this with a proper sting in it. The Mark 24 was the Royal Navy's wire-guided heavyweight torpedo and for years it did not work: the Mod 0 performed as designed in something like forty per cent of runs, and one of its habits was to dip on launch and cut its own guidance wire. In May 1982 that arithmetic had a consequence. When HMS Conqueror was ordered to sink the General Belgrano, her commanding officer declined to risk the modern torpedo and loaded Mark VIIIs instead, a design from the 1920s improved during the Second World War. He fired three and hit with two, and the Royal Navy sank an enemy cruiser with a weapon older than most of the men who fired it.

What followed was an urgent programme to make the thing work, and by the early 1980s Marconi had produced the Mod 2, with reliability up to around eighty per cent, which the Navy accepted as the most that could be got out of a design that could not be developed any further. Proving it needed something real to shoot at. So on 15 July 1984 they fired a Sea Eagle at Devonshire, and two days later HMS Splendid put a Mod 2 Tigerfish into her and sank her. A ship that had been the fleet's first guided missile destroyer was expended to demonstrate that the fleet's guided torpedo had finally stopped embarrassing everybody.

HMS Devonshire was finally sunk by the submarine HMS Splendid, a Swiftsure-class nuclear attack boat that had herself been on real war patrol barely two years earlier, shadowing the Argentine carrier 25 de Mayo during the Falklands War, as a target on 17 July 1984 in the North Atlantic, a fitting if slightly melancholy end for a ship that had pioneered guided missile technology for the Royal Navy over two decades earlier, ultimately destroyed by precisely the kind of guided weapon her own generation of warships had been built to help defend against.