HMS Royal Oak was sunk late on the night of 13 October 1939 after the entered Scapa Flow by bypassing its blockship defences. Initially Kapitänleutnant Günther Prien, the commander of U-47, had been disappointed to find that the Royal Naval anchorage was largely empty; this was the result of a recent order from Admiral Charles Forbes to clear Scapa Flow in case of air attack. However Royal Oak was retained because she carried a large battery of anti-aircraft guns. On sighting the battleship, Prien began his first attack run at 00:58hrs by firing three torpedoes. Only one caused a glancing blow on the bow of Royal Oak. An alarm was raised aboard ship, however, it was mistakenly given for "danger of a potential internal explosion" not for a submarine attack. When no explosion seemed likely, most crew members returned to their bunks. At 01:13hrs Prien began his second run. This time all three torpedoes struck Royal Oak amidships causing a huge explosion followed by a severe list to starboard. Prien used the ensuing confusion to escape from Scapa Flow. As the crew scrambled to leave the stricken battleship, rescue boats set out from the shore as nearby ships responded. However the darkness, oil slick and low water temperature meant that many of those who did escape the ship drowned before they could be rescued. Royal Oak rolled over and sank 15 minutes after being hit. A total of 835 crew were killed in the disaster, a further 386 were rescued. Rear-Admiral Blagrove was not among the survivors. His body was not recovered and the manner of his death is unknown. Blagrove's family became aware of the sinking from newspaper billboards in Edinburgh the following day but were not overly concerned for his safety. They were notified of his death 24 hours later. Legacy Blagrove's name is included on the Portsmouth Naval Memorial as his remains were never recovered. His actual gravesite, the wreck of Royal Oak, is a protected war grave and a memorial to all the men who died aboard her stands in St. Magnus Cathedral on the Orkney Islands. The islanders themselves also maintain the memory of those lost on the battleship and an annual ceremony remembers them at the site of the wreck. Blagrove's widow later worked on the efforts to break the codes of the German Enigma machine at Bletchley Park, and his family have made