British signals intelligence decrypted German wireless transmissions, allowing Jellicoe enough time to deploy the Grand Fleet in an attempt to engage in a decisive battle.

[35] On 5 November 1918, in the final week of the First World War, Royal Oak was anchored off Burntisland in the Firth of Forth accompanied by the seaplane tender Campania and the light battlecruiser Glorious.

[38] What began as a simple dispute between Rear-Admiral Bernard Collard and Royal Oak's two senior officers, Captain Kenneth Dewar and Commander Henry Daniel [Wikidata],[b][39] over the band at the ship's wardroom dance,[c] descended into a bitter personal feud that spanned several months.

On realising that the relationship between the two and their flag admiral had irretrievably broken down, Keyes hurriedly convened a Board of Enquiry, the outcome of which was to remove all three men from their posts and send them back to England.

[43] The Board sat on the eve of a major naval exercise, which Keyes was obliged to postpone, causing rumours to fly around the fleet that the Royal Oak had experienced a mutiny.

[46] In a pair of highly publicised courts-martial held aboard HMS Eagle at Gibraltar, both were found guilty and severely reprimanded, leading Daniel to resign from the Navy.

[49] Daniel attempted a career in journalism – notably a prominent anti-noise campaign, conducted through the Daily Mail, for whom he worked as correspondent[50] – but this was unsuccessful and, after a number of other jobs, his health deteriorated and he died in South Africa in 1955.

[53] The scandal proved an embarrassment to the reputation of the Royal Navy, then the world's largest, and it was satirised at home and abroad through editorials, cartoons,[54] and even a comic jazz oratorio composed by Erwin Schulhoff.

[61] In July, as the war in northern Spain flared up, Royal Oak, along with her sister HMS Resolution rescued the steamer Gordonia when Spanish Nationalist warships attempted to capture her off Santander.

Royal Oak portrays a rebel battleship El Mirante, whose commander forces a British captain (played by Robert Douglas) into choosing between his lover and his duty.

On 24 November 1938, she returned the body of the British-born Queen Maud of Norway, who had died in London, to Oslo for a state funeral, accompanied by her husband King Haakon VII.

[65] Paying off in December 1938, Royal Oak was recommissioned the following June, and in 1939 embarked on a short training cruise in the English Channel in preparation for another 30-month tour of the Mediterranean,[66] for which her crew were issued tropical uniforms.

[66] The next few weeks of the Phoney War proved uneventful, but in October 1939 Royal Oak joined the search for the Gneisenau, which had been ordered into the North Sea as a diversion for the commerce-raiding heavy cruisers Deutschland and Admiral Graf Spee.

[72] Two submarines unsuccessfully attempted infiltration during the First World War: on 23 November 1914 U-18 was rammed twice before running aground with the capture of her crew,[73][74] and UB-116 was detected by hydrophone and destroyed with the loss of all hands on 28 October 1918.

[79] Dönitz was aided by high-quality photographs from a reconnaissance overflight by Siegfried Knemeyer (who received his first Iron Cross for the mission), which revealed the weaknesses of the defences and an abundance of targets.

[79] He directed Prien to enter Scapa Flow from the east via Kirk Sound, passing to the north of Lamb Holm, a small, low-lying island between Burray and Mainland.

[80] Prien initially mistook the more southerly Skerry Sound for the chosen route, and his sudden realisation that U-47 was heading for the shallow blocked passage forced him to order a rapid turn to the northeast.

Mindful of the unexplained explosion that had destroyed HMS Vanguard at Scapa Flow in 1917,[74][g] an announcement was made over Royal Oak's tannoy system to check the magazine temperatures,[h] but many sailors returned to their hammocks, unaware the ship was under attack.

As the sinking battleship began to list to starboard, Gatt ordered Daisy 2 to be cut loose, his vessel becoming briefly caught on Royal Oak's rising anti-torpedo bulge and lifted from the sea before freeing herself.

He defended the Royal Navy tradition of sending boys aged 15 to 17 to sea, but the practice was generally discontinued shortly after the disaster, and under 18-year-olds served on active warships in only the most exceptional circumstances.

[97] The Nazi Propaganda Ministry was quick to capitalise on the successful raid,[109][110] and radio broadcasts by the popular journalist Hans Fritzsche displayed the triumph felt throughout Germany.

[l] Ghost-written for him by a journalist, Paul Weymar, following some brief interviews with Prien in March and April 1940, the manuscript was edited by the Oberkommando der Wehrmacht (the German high command) and the Reich Ministry of Propaganda.

[117] Their official report into the disaster condemned the defences at Scapa Flow, and censured Sir Wilfred French, Admiral Commanding, Orkneys and Shetlands, for their unprepared state.

French was placed on the retired list,[118] despite having warned the previous year of Scapa Flow's deficient anti-submarine defences, and volunteering to bring a small ship or submarine himself past the blockships to prove his point.

The question of "deadlights" was also considered; these were ventilated metal plates that replaced the glass panes in the scuttles or portholes when ships were in port, allowing the wartime blackout to be observed.

A funeral parade for the dead took place at Lyness on Hoy on 16 October; many of the surviving crew, having lost all their own clothing on the ship, attended in borrowed boiler suits and gym shoes.

Serving as a 17-year-old boy, first class, he had been on watch on the bridge when the ship was struck and jumped from the sinking vessel, swimming in the wrong direction until he was picked up by a boat and transferred to the Daisy 2.

[143] Royal Oak's status as a war grave required that surveys and any proposed techniques for removing the oil be handled sensitively: plans in the 1950s to raise and salvage the wreck had been dropped in response to public opposition.

[144] In addition to the ethical concerns, poorly managed efforts could destabilise the wreck, resulting in a mass release of the remaining oil;[145] the ship's magazines also containing many tons of unexploded ordnance.

[142] Rebreather diver Emily Turton announced at the EUROTEK advanced diving conference in December 2018 that an international team of experts were surveying the wreck of Royal Oak to create a three-dimensional image of the war grave.