Scapa Flow

Scapa Flow (/ˈskɑːpə, ˈskæpə/; from Old Norse Skalpaflói 'bay of the long isthmus') is a body of water in the Orkney Islands, Scotland, sheltered by the islands of Mainland, Graemsay, Burray, South Ronaldsay and Hoy. Its sheltered waters have played an important role in travel, trade and conflict throughout the centuries. Vikings anchored their longships in Scapa Flow more than a thousand years ago. It was the United Kingdom's chief naval base during the First and Second World wars, but the facility was closed in 1956.

Since the scuttling of the German fleet after World War I, its wrecks and their marine habitats form an internationally acclaimed diving location.

Scapa Flow hosts an oil port, the Flotta oil terminal. In good weather, its roadstead (water of moderate conditions) allows ship-to-ship transfers of crude oil product. The world's first ship-to-ship transfer of liquefied natural gas (LNG) took place in Scapa Flow in 2007 transferring 132,000m³ of LNG. This occurred in 2007 by Excelerate Energy between the vessels Excalibur and Excelsior.

Scapa Flow has a shallow sandy bottom not deeper than 60 metres (200 ft) and most of it is about 30 m (100 ft) deep; it is one of the great natural harbours and anchorages of the world, with sufficient space to hold multiple navies. The harbour has an area of 324.5 square kilometres (125.3 sq mi).

Scapa Flow has been designated an Important Bird Area (IBA) by BirdLife International because it supports populations of wintering velvet scoters, horned grebes, common loons, European shags and Eurasian curlews, as well as breeding black guillemots.

The Viking expeditions to Orkney are recorded in detail in the 11th century Orkneyinga sagas and later texts such as the Hákonar saga Hákonarsonar.

According to the latter, King Haakon IV of Norway anchored his fleet, including the flagship Kroussden that could carry nearly 300 men, on 5 August 1263 at St Margaret's Hope, where he saw an eclipse of the sun before he sailed south to the Battle of Largs.

En route back to Norway Haakon anchored some of his fleet in Scapa Flow for the winter, but he died that December while staying at the Bishop's Palace in Kirkwall. In the 15th century towards the end of Norse rule in Orkney, the islands were run by the jarls from large manor farms, some of which were at Burray, Burwick, Paplay, Hoy, and Cairston (near Stromness) to guard the entrances to the Flow.