HMS Drake had been the lead ship of her class, laid down at Pembroke Dock in Wales on 24 April 1899 and launched on 5 March 1901. She was an armoured cruiser, a category of warship that has since disappeared but in her day was one of the dominant capital ships of the Royal Navy. At 14,100 tons, 553 feet long with a beam of 71 feet, she was powered by two four-cylinder triple-expansion steam engines drawing steam from forty-three Belleville boilers. Her trial speed was 24.11 knots, fast for her size. She carried two breech-loading 9.2-inch Mk X guns in single turrets fore and aft, a dozen quick-firing 12-pounders for defence against torpedo boats, and a complement of nine hundred officers and ratings.

Drake's career reads like the index of British naval history. Her first commanding officer was Captain Francis Bridgeman, who would later become First Sea Lord, the professional head of the Royal Navy. Her second was John Jellicoe, who would command the Grand Fleet at Jutland in 1916 and then become First Sea Lord himself. From 1905 to 1907 she served as flagship of the 2nd Cruiser Squadron under Admiral Prince Louis of Battenberg, the German-born British prince whose family would later anglicise their name to Mountbatten. In 1911 she sailed to Australia as flagship of the Australia Station. By 1914 she was back home, attached to the 6th Cruiser Squadron, and when war broke out in August of that year she found herself part of the Grand Fleet sealing the northern exits from the North Sea.

Drake's strangest mission came in October 1914, just weeks after the war began. Under the command of Captain Aubrey Smith, she sailed for Arkhangelsk on the White Sea coast of Russia and lay thirty miles off shore for several nights while small boats brought Russian gold bullion out to her under the cover of darkness. The total cargo was worth eight million pounds in 1914 money - several hundred million in modern terms - and it was needed to pay for Russian war supplies being manufactured in British factories. Drake brought it home to Britain. The transaction was secret then and is hardly mentioned now, but it gives a sense of what a flagship cruiser was actually for: not just to fight, but to project an empire's reach into the most awkward corners of a world war.

By 1917 Drake was older, slower, and increasingly out of place. The Battle of Jutland had shown that armoured cruisers could not stand up to dreadnought-era gunfire. She had been moved to convoy escort duties on the North America and West Indies Station, shepherding cargo ships across the Atlantic. On the morning of 2 October 1917, her convoy HH 24 had dispersed near Rathlin Island for its various destinations and Drake was steaming home in clear weather. At 09.05, U-79's torpedo hit her under the second funnel. The torpedo struck the No. 2 Boiler Room. Two engine rooms and the boiler room flooded. The eighteen men killed by the explosion were almost all in those compartments - boiler-room ratings, mostly young men, doing the hardest and least visible work on the ship. We have their names because the Admiralty kept records. Among them were fathers, sons, brothers, men who never came home from a war that took millions of others like them. The torpedo also knocked out Drake's steam-powered steering. With great difficulty, the crew brought her toward Church Bay on Rathlin Island and dropped anchor; she capsized later that afternoon.

Eighteen is a number small enough to feel. It is fewer than a single rugby squad. It is one classroom of children. The Drake lost 18 sailors that morning, and the eighty-two who survived would have spent the rest of their lives carrying the names of the eighteen who did not. There is no published memorial at the wreck site, no plaque on Rathlin pier, no grand monument in Belfast. The men's names appear on Royal Navy rolls and on the war memorials of the towns they came from. The wreck itself, sitting in fifteen to nineteen metres of water in Church Bay, became their resting place. Salvage of removable material began in 1920 and continued for years. In 1962, a steam trawler called the Ella Hewett struck the wreck and sank almost on top of her. Ammunition and ordnance were salvaged and the wrecks were demolished with depth charges in the 1970s, partly to make the site safer for other shipping.

What is left of HMS Drake has been a scheduled historic monument since June 2017, the centenary of her sinking. The wreck lies on her starboard side in shallow water, broken but still recognisable in places: the great twin shafts that drove her engines, the curved plates of her armour belt, fragments of her boilers and turrets. The depth makes the site accessible to recreational divers, the visibility is generally good, and most weekends in summer there are dive boats above her position. The divers come for the engineering, for the scale, for the history. The eighteen men who died stayed on board after the ship turned over, and most divers respect that quietly. The dive briefing tends to remind people: this is a war grave. Look, photograph, do not take. The Drake belongs to the sea now, and to the eighteen who travelled with her to the bottom of Rathlin Sound on a clear October morning a hundred and nine years ago.