The area of sea below high water springs enclosed by a line from a point on the East coast of the Orkney Mainland at 59° 00'N 2° 54.5'W; then East to a point at 59° 00'N 2° 30'W; then North to a point at 59° 15'N 2° 30'W; then West to a point on the East coast of Sanday at 59° 15'N 2° 30.5'W; then along the shoreline of Sanday to a point at 59° 15'N 2° 38.5'W; then West to a point on the East coast of Eday at 59° 15'N 2° 45.01'W; then along the shoreline of Eday to a point at 59° 15'N 2° 45.08'W; then West to the South East coast of Westray at 59° 15'N 2° 50'W; then along the shoreline of Westray to a point at 59° 15'N 2° 53'W; then West to a point at 59° 15'N 3° 13'W; then South to Costa Head on the Orkney Mainland at 59° 9.2'N 3° 13'W; then along the shoreline to the start point at 59° 00'N 2° 54.5'W.