HMS Tintagel Castle (K399): A Late War Kill in the Bay of Biscay

Laid Down at Troon

HMS Tintagel Castle was built by the Ailsa Shipbuilding Company at Troon, laid down on 19 April 1943, launched on 13 December that year and completed on 7 April 1944, a Castle-class corvette equipped with a 4-inch gun, a Squid anti-submarine mortar and modern ASDIC and radar systems, representing the most up-to-date anti-submarine technology the Royal Navy had available by that stage of the war.

What Four Years of Complaints Produced

The Castle class deserves an introduction, because it is what happens when a navy listens. The Flower-class corvettes that carried the first three years of the Atlantic war were adapted from a whale catcher, and everybody who sailed in one had the same list of complaints: too short, so that she pitched violently and could not be driven into a head sea; too wet; a tiny open bridge; accommodation that was genuinely dangerous to health on a long convoy; and an armament that had been adequate in 1940 and was not by 1943. The Castles are the answer to that list. They are about forty feet longer, with a raised forecastle carried further aft, an enclosed bridge, decent accommodation and a single mast, and forty-four of them were built.

They are named after British castles, which is how a corvette came to be called Tintagel, after the ruin on the Cornish cliffs that has been associated with the legend of Arthur since the twelfth century. Several of her sisters are here, among them HMS Launceston Castle (F397), another Cornish name, and HMS Berkeley Castle (K387), who was sunk in a dry dock by a flood eight years after the war ended.

Convoy Escort Duty

Like the rest of her class, Tintagel Castle spent her wartime service on convoy escort duty, part of the vast, unglamorous effort that kept Britain's vital supply lines open across the closing years of the Battle of the Atlantic.

The Weapon That Actually Killed Submarines

The Squid is the reason the Castles matter, and it is worth explaining because it appears everywhere as a word and nowhere as a thing. A depth charge is dropped over the stern or thrown out to the side, which means the attacking ship has to pass directly over the submarine to use it. In the last seconds of that run her own sonar loses contact, because the beam cannot look straight down; so the final approach is made blind, on a guess about where the submarine has moved to, and the submarine's captain knows exactly when to turn because he can hear the ship overhead.

Squid removes all of that. It is a three-barrelled twelve-inch mortar mounted on the forecastle, which throws a pattern of three large charges about three hundred yards ahead of the ship, so that contact is never lost. Better still, it is fired automatically: the sonar set feeds a computer, the computer works out the range, the depth and the moment, and the mortar goes off on its own when the geometry is right, with no human being deciding when to press anything. In 1943 that was close to science fiction.

The numbers make the argument better than any description. Across the whole war, depth charges sank something like eighty-five submarines in more than five thousand attacks, which is roughly one kill per sixty attempts. Squid, fitted to a few dozen ships in the last two years, sank about seventeen in around fifty attacks: better than one in three. Tintagel Castle carried one, and used it.

Sinking U-878 in the Final Weeks

On 10 April 1945, just weeks before the war in Europe ended, Tintagel Castle joined HMS Vanquisher in sinking the German submarine U-878 with depth charges in the Bay of Biscay, a notably significant late-war success at a time when German U-boats were still capable of posing a real threat even as their overall campaign collapsed around them.

April 1945 is worth pausing on too. The war in Europe had four weeks left, the German army was collapsing, and the U-boat arm was still sending boats out and still losing them at a rate that is difficult to comprehend: something like a hundred and fifty submarines were destroyed in the last four months of the war, many of them on their first patrol, crewed by boys. U-878 was one of them. She went down in the Bay of Biscay on 10 April with every man aboard, killed by two escorts and a weapon that had not existed when she was laid down, in a campaign that everybody involved already knew was lost.

Scrapped at Troon

HMS Tintagel Castle was decommissioned and scrapped at Troon, returning to the yard where she had been built, sources placing the date at either 1958 or 1960, closing out the career of a corvette whose confirmed U-boat kill came right at the very end of the campaign she had been built to fight.