Orkney at War

Scapa Flow is a stretch of water in the Orkney Islands of Scotland. In response to the expansion of the German Imperial High Seas Fleet, the British decided in 1904 that a northern naval base was essential to monitor the North Sea entries. Scapa Flow was selected as the primary base for the British Grand Fleet. Defensive measures were initiated by sinking over sixty blockships in the channels between the southern islands. Together with submarine nets, booms, and minefields, these barriers prevented enemy vessels and submarines from accessing the area. In 1916, the British fleet sailed from Scapa Flow for the Battle of Jutland, the largest naval engagement of World War I, which confirmed the Royal Navy's control over the North Sea and Atlantic for the remainder of the conflict.

After World War I, 74 ships from the Imperial German Navy's High Seas Fleet were held at Scapa Flow while awaiting their fate under the Treaty of Versailles. On 21 June 1919, after months of uncertainty, German Rear Admiral Ludwig von Reuter decided to scuttle the fleet, resulting in 53 ships being sunk. In 1922, the British Admiralty opened salvage rights to these vessels, marking the beginning of the largest maritime salvage operation in history.

During World War II, Scapa Flow once again served as the primary British naval base. The defenses from World War I had deteriorated. On 14 October 1939, the German submarine U-47, breached the defenses and sank the battleship HMS Royal Oak in Scapa Bay, claiming 833 lives from its 1,400-man crew.

Additional defenses such as new blockships, mines, and booms were installed, along with coast and anti-aircraft batteries and airfields. Winston Churchill also ordered the construction of the Churchill Barriers. These causeways, built by Italian prisoners of war, blocked the eastern approaches to Scapa Flow.

After World War II, the base at Scapa Flow was decommissioned in 1956.