Because of bad weather and insufficient coal, the merchant steamship was forced to break away from the military convoy off the coast of Ireland.
As the captain re-routed in emergency for Galway, on the west coast of Ireland, the Gairsoppa and its crew of 86 men were hit by a torpedo from a Nazi U-boat. She sank in icy seas within 20 minutes.
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The crew boarded three lifeboats. While two boats soon disappeared, a third lifeboat managed to sail for 13 days. Only one person, second officer Richard Ayres, survived the long journey to shore.
"Sources, including Lloyd's record of War Losses, indicate additional uninsured government-owned silver may have been aboard the SS Gairsoppa when she sank, but to date no uninsured silver has been located," Odyssey said in a statement.
Under the terms of a deal struck in 2011 with the UK Department for Transport, the Tampa, Fla.-based company will take 80 percent of the net proceeds.
Notable silver finds, including the first ingot recovered from the Gairsoppa, are currently on display at Odyssey's SHIPWRECK! exhibit at Discovery Times Square in New York City.