The Record
Royal Navy Revenge-class battleship, at anchor in Scapa Flow on the night of 14 October 1939. German submarine U-47 under Günther Prien threaded the blockship barriers at Kirk Sound and fired seven torpedoes; four struck, and she rolled over in thirteen minutes. 834 dead of 1,234 aboard, including 134 boy seamen. Prien returned to Berlin a national hero; the defences at Scapa were rebuilt as the Churchill Barriers.
The Vessel
HMS Royal Oak was a Revenge-class battleship of the Royal Navy, laid down at Devonport Dockyard in January 1914 and commissioned on 1 May 1916 at Devonport. She was 189 metres long, 29,150 tons standard displacement, with eight 15-inch guns in four twin turrets, a secondary battery of twelve 6-inch guns, and a design speed of 21 knots on four shafts. The Revenge-class had been built to replace the 1905-era pre-dreadnoughts of the Grand Fleet's second-line battle squadrons, and Royal Oak served in exactly that capacity from her commissioning through the interwar period and into the Second World War.
She fought at Jutland on 31 May 1916 as part of Vice-Admiral Sir Cecil Burney's 1st Battle Squadron; she fired 38 rounds of 15-inch, hit the German battleship Derfflinger once, and emerged undamaged. She served in the Mediterranean through the 1920s, participated in the international naval demonstration at Corfu in 1923, and patrolled the Spanish coast during the Spanish Civil War. She returned to the Home Fleet in early 1939 as one of five Revenge-class battleships then still in first-line service; of that class she was the best-maintained.
Her master at the outbreak of the Second World War was Captain William Benn. She had taken on 1,234 officers and ratings, including the unusually high number of 134 "boy seamen" in training, sixteen-year-old Royal Navy recruits on their first sea assignment. By September 1939 she was the flagship of Rear-Admiral Henry Blagrove, commanding the Home Fleet's 2nd Battle Squadron. She sailed from Scapa Flow through late September and early October on anti-invasion patrols in the Norwegian Sea, returning to anchor at Scapa Flow on 9 October 1939 for boiler cleaning and crew rest.
The Voyage
Scapa Flow, the Royal Navy's principal northern anchorage in the Orkney Islands, had been the Grand Fleet's main base since 1914. Its defences against U-boat penetration had been exhaustive in the First World War: seven blockships had been deliberately sunk in the eastern channels to close the routes that could not be guarded by mine and boom. By September 1939 the First War blockships had settled onto the harbour floor and some of the mid-century channels, specifically Kirk Sound, were no longer adequately blocked. The Admiralty's Scapa defence review of 1938 had identified the Kirk Sound gap and had recommended additional blockships; the blockships had been ordered but had not yet arrived by October 1939.
The German submarine U-47, commanded by 31-year-old Kapitänleutnant Günther Prien, a veteran merchant-navy officer who had transferred to the Kriegsmarine in 1933, departed Kiel on 8 October 1939 with the specific mission of penetrating Scapa Flow. The mission had been planned by Commodore Karl Dönitz on the basis of Kriegsmarine aerial photographs of Kirk Sound taken in September 1939 that showed the inadequate blockship gap. Prien made the penetration on the evening of 13 October under cover of slack water and a moonless sky. He navigated U-47 on the surface between the blockships with two metres of clearance on each side.
Inside Scapa he found himself closer to the anchored Home Fleet than any German submariner had been since 1918. He identified HMS Royal Oak immediately by her silhouette. He fired four torpedoes from 3,000 metres.
The Disaster
Of Prien's first spread of four torpedoes, one struck Royal Oak's starboard bow at approximately 00:58 on 14 October 1939. The detonation was minor; the bow anchor capstan was damaged but the hull compartments adjacent to the strike were not breached. Captain Benn and Admiral Blagrove both assumed the bang was either a small internal explosion or a collision. A damage-control party was dispatched to the bow. Twenty-three minutes passed between the first strike and the second.
Prien, under the assumption that his first spread had failed to cripple the battleship, turned U-47 and fired a second spread of three torpedoes at 01:21. This spread struck true: three torpedoes hit in quick succession, one under the starboard forward funnel and two at the starboard quarter. The second spread breached Royal Oak's torpedo protection, ignited the aft 15-inch magazine, and broke her back. She rolled onto her starboard side and sank in thirteen minutes, at 01:34.
834 of her 1,234 crew died, including Admiral Blagrove, 120 boy seamen, and nearly every man in the forward and aft compartments. 386 men survived, most of whom were rescued from the harbour by the tender Daisy 2, the small boat Supply, and the rescue tug Scott. The sinking was the worst single-ship loss of life Scapa Flow had seen in either world war.
The Legacy
Prien and U-47 escaped Scapa on the outgoing tide at 02:00 on 14 October and returned to Kiel to the most extensive propaganda welcome the Kriegsmarine would ever stage. Prien was awarded the Knight's Cross on 18 October 1939 by Hitler in person, was promoted to Korvettenkapitän, and became the first U-boat commander to be declared a national hero. The penetration of Scapa and the sinking of Royal Oak had been an intelligence and tactical coup on a level the Kriegsmarine had not previously achieved. Prien was lost with U-47 on 7 March 1941 in North Atlantic operations against convoy OB-293.
The Admiralty's immediate response to the sinking, ordered by Churchill as First Lord of the Admiralty within a week, was the construction of the "Churchill Barriers" across the four eastern approaches to Scapa Flow. The barriers were built by Italian prisoners of war between 1940 and 1944 and permanently closed the channels through which U-47 had penetrated. They survive as the causeways by which the eastern Orkney islands are now connected to the mainland. The Churchill Barriers are Royal Oak's direct memorial.
Her wreck lies at 30 metres in Scapa Flow, upside down, her bow pointing north. She is a protected war grave under the Protection of Military Remains Act 1986 and is declared a controlled site: only authorised divers acting on Royal Navy clearance may approach her. An annual Royal Navy diving detail replaces the White Ensign flown on her upturned propeller shaft every year on the anniversary of her loss. The Ensign is seen by no one but the diver who raises it. The names of the 834 dead are read out at St. Magnus's Cathedral in Kirkwall every 14 October. The boy seamen are read first.