The area of sea around the islands of Orkney below mean high water springs enclosed by a line extending from Tor Ness on the island of Hoy at 58° 47'N 3° 17.5'W; then due south to a point at 58° 45'N 3° 17.5'W; then due east to Barth Head on South Ronaldsay at 58° 45'N 2°59'W; then north and west along the shoreline of South Ronaldsay and the mainland to Breck Ness on the mainland at 58° 58'N 3° 21'W; then south and west to the Kame of Hoy on Hoy at 58° 55.5'N 3° 24'W; then east, south and west along the shoreline of Hoy to the start point at Tor Ness at 58° 47'N 3° 17.5'W.