A U.S. deep-sea exploration company says it has recovered about 48 tons of silver from a British cargo ship that was sunk by a torpedo during World War II.

Tampa, Fla.-based Odyssey Marine Exploration Inc. said Wednesday it's the heaviest and deepest recovery of precious metals from a shipwreck.

The haul comes from the SS Gairsoppa, which was hit by a German U-boat about 300 miles (483 kilometers) off Ireland's coast. It sits 15,420 feet (4,700 meters) deep.

So far, workers have brought up more than 1,200 silver bars or about 1.4 million troy ounces. As of mid-day Wednesday, it was worth about 23.7 million pounds (about $37 million).

The company is under contract by the British government and will get to keep 80 percent of the haul after expenses.