Brei Holm and Maiden Stack guard the harbour entrance to the south . The former is a tidal island and was a leper colony until the 18th century ( although it has been suggested that many of the " lepers " it were suffering from a vitamin deficiency rather than leprosy ) . The latter 's name relates to a story from the 14th century . Lord Thorvald Thoresson is said to have constructed the tiny house at its top , whose ruins are still visible , in order to " preserve " his daughter from men . Unfortunately for his plans , when she left she was found to be pregnant ; in another version of the story , she and her fisherman sweetheart successfully eloped . West Voe , the inner part of which is called ' Robies Noust ' is the main voe in the north coast , the smaller Culla Voe lying immediately to the west .