On 24th February 1917 the cargoship Glen Isla, left Lerwick in convoy, bound for Slemmestad, Oslo, Norway, with a cargo of coal. Less than a mile from the Bressay Lighthouse, at Kirkabister she collided with another vessel, the torpedoed Glen Elg under tow, and sank. All 23 crew were rescued. The above mentioned Glenelg, may possibly be the vessel of the same name which was extensively damaged by striking a mine, a few miles to the south of where this incident occured, just over six months later.
The Glen Isla (also spelled Glenisla) was a Dundee registered steamer of 1423 GRT built by W. B. Thomson of Dundee in 1878. She had a somehow "chequered" career being involved in a number of accidents and collisions. She scuttled twice in 1902 and in 1908, when her cargo caught fire. Just before WW I (she later served as a decoy vessel for the Admiralty until 1916) she cut a French trawler in two, drowning 4 crew.
The wreck was located at 60 08 24N, 001 07 48W nn the 29th of June 1988