The Princess Royal joined survivors for the ceremony at the scene
The Princess Royal has joined survivors of one of the darkest days in the history of Royal Navy to lay wreaths where a battleship was sunk
HMS Royal Oak was torpedoed by a German U-boat at its base at Scapa Flow, in Orkney, on 14 October 1939.
It sank with the loss of 833 lives, including many teenage sailors. Almost 400 crew were saved.
Princess Anne was among those to lay a wreath during a ceremony to mark the 70th anniversary of the tragedy.
The navy's top officer in Scotland, Rear Adm Martin Alabaster, said: "The service was a very moving tribute to the men who lost their lives in one of the Royal Navy's blackest days of World War II.
Almost 400 crew survived after the Royal Oak sank
"It was an honour to be able to be part of this ceremony and to speak to the survivors who had made the journey to remember their lost friends and colleagues."
World War II was just a few weeks old when the battleship was torpedoed as most of the crew slept.
The first salvo from U-47 caught those on board by complete surprise and the ship sank within minutes after a second torpedo wave struck 15 minutes later.
The submarine had navigated a narrow strait to enter what was thought to be a safe haven for the British fleet.
More than 100 of the dead were "boy sailors", between the ages of 14 and 18. Many of those who survived were badly burned.
The tragedy has never been forgotten on Orkney.
The wreck is an official maritime war grave protected by the local council, and there is a permanent memorial located inside Kirkwall's St Magnus Cathedral.
On Sunday morning, a service was held in the cathedral, and a parade took place featuring local dignitaries, the Royal British Legion and youth organisations.