HMS Royal Oak was a Revenge-class battleship launched in 1914. The ship was torpedoed while anchored at Scapa Flow in Orkney on October 14, 1939 by German submarine, U-47. Of the 1,234 men on board, 833 were killed. The wreck is designated as a war grave and a buoy marks the spot. Every year Royal Navy divers place a White Ensign at the stern of the ship in memory.