October 14, 1939
Scapa Flow in the Orkneys has long been considered impregnable to submarine attack. During the Great War, two German submarines were destroyed in the attempt. The major entrances are covered by boom nets, which can be retracted by tugs to allow friendly shipping through. Block ships have been sunk and cables strung in other entrances to prevent infiltration through those shallower and narrower ingresses.
Gunther Prien, commanding U-47 was handpicked by Donitz for the infiltration mission and successfully navigated between the block ships in the narrow Kirk Sound on the eastern side of the Flow. Scouting through the flow, Prien was surprised to find the anchorage largely empty, due to an Admiralty order to disperse the fleet after German reconnaissance aircraft had overflown the base in the preceding week. Royal Oak, being slow and obsolete was kept in the anchorage to augment the scarce anti-aircraft guns in the area.
U-47 was able to enter the flow after midnight on the moonless night and scout to the south of the anchored warships. He then made two attack runs at Royal Oak firing a total of 7 torpedoes. During the first attack run at 00:58. three of the four bow torpedoes and one stern tube were fired. Only four of these launched as one of the forward tubes stuck and only one torpedo actually hit the Royal Oak, causing minor damage to the bow. Assuming this was an explosion in the forward flammable store, the crew were unaware they were under attack and only a small number of the crew responded by checking magazine temperatures and responding to the damage. Many of the crew returned to their hammocks. The starboard anchor chain had been severed and clattered noisily but this seems to have been largely unnoticed.
A second attack run 15 minutes later saw three further torpedoes launched from the bow tubes, all of which hit Royal Oak amidships and caused extensive damage. The ship quickly listed and had lost electrical power. The Marines and Stoker’s boys messes were destroyed and she soon listed to 15 degrees causing the open portholes on the starboard side to go under. Within 13 minutes the ship rolled over past 45 degrees and sank at 01:29. Meanwhile U-47 escaped back through the same route out into the North Sea. Prien will no doubt be handsomely rewarded for this.
Had Prien searched further he could have sunk a much more valuable ship, as the newly commissioned light cruiser HMS Belfast and three other ships were within 4 nautical miles of his initial scouting run. The loss of the ship itself was insignificant in the eyes of the Royal Navy, obsolete and slow, she had been unable to keep up with the rest of the fleet during the recent search for Gneisenau, however the loss of 833 of the ship’s 1234 men was a telling blow. The dead included all ranks from Rear-Admiral Henry Blagrove to more than 100 boy seamen who had not yet reached 18 years of age. The tender daisy was responsible for saving almost all of the survivors, including the ship’s Captain Willima Benn. A few men did make it the 800m to shore through the oily and cold water.
Most significantly, the morale of the nation suffered a cruel blow at this early stage of the war and the previously assumed impenetrability of Scapa Flow is proven no more than an illusion.