Scapa Flow has been as an important haven for over 1000 years. This stretch of water, very roughly 20km from east to west and 15km from north to south lies, atoll-like, within the shelter of the surrounding Orkney islands. The result is one of the largest natural harbours in the world.
Today's Scapa Flow is home to a major oil terminal at Flotta. Here up to 10% of the UK's oil arrives by pipe from North Sea oilfields before being transferred to tankers for shipment around the world. Traffic through these busy waters is overseen by the Scapa Flow Control Centre at Scapa Bay, a mile south of Kirkwall.
And with a flat bottom at depths of between 60 and 150 feet, an absence of strong currents, and an abundance of wrecks, it is also the centre of a major tourist diving industry, based primarily at Stromness and on Burray and South Ronaldsay. About 15 dive boats cater for up to 20,000 divers who come to Orkney each year to dive Scapa Flow.
Though no evidence remains, Scapa Flow was probably used for fishing by the builders of Maes Howe, 5000 years ago. But it first came into recorded history with the Vikings. Their world extended from Iceland to Ireland, and from Scandinavia to North Eastern England, and Orkney lay at its centre. The name comes from the Old Norse, Skalpeid-floi, or Bay of the Long Isthmus.
In 1670 Stromness, already a whaling and fishing centre, became the main European base for the Hudson's Bay Company. Later, in 1813, commercial shipping going around the north of Scotland to Scandinavia came under threat from US privateers supporting the French. This resulted in the first shore defences overlooking Scapa Flow, with the construction of the Hackness Battery and two Martello Towers protecting Longhope Sound, at the southern end of Hoy.
But Scapa Flow would probably have remained no more than a natural wonder had not war clouds gathered over Europe in the early 1900s. With a war with Germany in prospect, the Royal Navy needed a base for the Grand Fleet better located to counter the German High Seas Fleet based in Baltic ports. Scapa Flow was chosen, and many thousands of service personnel were based on the surrounding islands, and on Hoy and Flotta in particular.
In 1919 the German High Seas Fleet was brought to Scapa Flow after the German surrender. A misunderstanding over the progress of the peace talks led the German commander, Admiral von Reuter, to believe that war was about to resume. To avoid his fleet falling into British hands he ordered the scuttling of the 74 German battleships and other warships at anchor in Scapa Flow, on 21 June 1919. Many of these were salvaged for scrap after the war, but others still remain on the sea bed as a magnet for divers.
1939 brought war with Germany again, and Scapa Flow was reactivated as the main base for the Royal Navy. One of Scapa Flow's most tragic and memorable events took place very early in the war when, on the night of 14 October 1939, the German submarine U-47 found a way through the sunken blockships intended to seal off the narrow eastern approaches to Scapa Flow. It torpedoed HMS Royal Oak, at anchor in Scapa Bay, and made good its escape. 833 members of the Royal Oak's crew were killed. HMS Royal Oak remains on the floor of Scapa Flow as a war grave, and diving it is not permitted.
This event led to a visit by Winston Churchill to Orkney and the starting of the building of the Churchill Barriers, causeways linking together the five eastern islands of the group and ensuring that side of Scapa Flow would in future be completely secure. The barriers were completed in May 1945, and remain in use as causeways today.
WWII left other legacies around Scapa Flow. Every headland on the surrounding islands seems to carry a disused lookout and a gun emplacement or two. And on Hoy and Flotta it can seem that most of the existing structures are military in origin.
Most striking of all, however, is the Scapa Flow Visitor Centre. This is at Lyness on Hoy, very close to the terminus for the Hoy vehicle ferry from Houton on the Mainland. Lyness housed the main oil storage facilities for the fleet during the war, and the visitor centre is housed in the old pumping station. Behind it is an oil tank (the only survivor of many that once stood here) that is today used to house an audio-visual display. Less obvious are the vast underground oil tanks excavated in the hillside behind, the spoil from which was used to build Lyness's large harbour.
The visitor centre still houses the oil pumping equipment, alongside a large range of exhibits that give a real feel for Lyness and for Scapa Flow in the 1940s. Here you can see displays and models showing how Scapa Flow's defences worked, plus models showing the 1919 German Fleet when it was scuttled. There's something for everyone here, from large guns and torpedoes though to photographs and more personal memorabilia that begin to give a sense for the people who spent a part of their lives here, and sometimes died here.
Nearby at Lyness is the Naval cemetery in which those whose bodies were recovered from HMS Royal Oak in 1939 are buried, alongside victims of the WWI Battle of Jutland, the sinking of HMS Hampshire while taking Lord Kitchener to Russia in 1916 and many other incidents from two world wars.
Scapa Flow is an atmospheric place. Today's intense oil-related activity exists alongside the relics of many earlier periods of use, both on land and under water. The history of Scapa Flow is intimately intertwined with the history of Orkney, and an understanding of one requires some understanding of the other.