A Florida-based exploration company confirmed Monday a discovery that is the stuff of which shipwreck movies are made —a Second World War-era British cargo ship known as the SS Gairsoppa that was carrying silver valued today at more than $200 million US when it was torpedoed by a German U-boat.

Odyssey uses remotely operated vehicles like this one to search for sunken ships. (Odyssey) Odyssey Marine Exploration says it has confirmed the identity and location of the shipwreck site — nearly 4,700 metres below the surface of the North Atlantic, about 480 kilometres off the coast of Ireland in international waters.

The Tampa company, working under contract for the British government, says research and official documents indicate the ship was carrying seven million ounces of silver, including more than three million ounces of private silver bullion insured by the government.

If recovered, it would be the largest known precious metal cargo ever retrieved after being lost at sea.

Neil Cunningham Dobson, Odyssey's principal marine archeologist, says most of Gairsoppa's crew didn't survive the long journey to shore. (Odyssey) Mark Gordon, Odyssey president and chief operating officer, says the shipwreck area was located with a system called side-scan sonar, and then visually inspected in less than two months from the start of the operation.

"We've accomplished the first phase of this project — the location and identification of the target shipwreck — and now we're hard at work planning for the recovery phase," said Andrew Craig, Odyssey senior project manager. "Given the orientation and condition of the shipwreck, we are extremely confident that our planned salvage operation will be well-suited for the recovery of this silver cargo."

The SS Gairsoppa was a 125.5-metre steel-hulled cargo ship that was torpedoed in February 1941. In 2010, the U.K. Government Department for Transport awarded Odyssey the salvage contract for the cargo of the ship.

Salvage operations targeted for spring

Under the salvage agreement, Odyssey would retain 80 per cent of the net salvaged value of the silver bullion recovered under the contract, while the British government will get the rest, the company says.

To inspect the site, an Odyssey team conducted remotely operated vehicle operations. The video and photographs acquired during the exploration of the shipwreck were reviewed and analyzed to confirm the identity of the shipwreck as being the SS Gairsoppa.

The SS Gairsoppa was torpedoed by a German U-Boat in February 1941. Research and official documents indicate that the ship was carrying as much as 7,000,000 ounces of silver. (Odyssey) The expedition and resulting data were used to evaluate the condition of the shipwreck and to begin planning for recovery operations.

After the ship was torpedoed, it's believed all 85 men aboard died, including one officer who survived nearly two weeks in a lifeboat.

"Even though records indicate that the lifeboats were launched before the ship sank, sadly most of her crew did not survive the long journey to shore," said Neil Cunningham Dobson, Odyssey's principal marine archeologist. "By finding this shipwreck, and telling the story of its loss, we pay tribute to the brave merchant sailors who lost their lives."

Odyssey has begun the process of specifying and assembling the tools and equipment for salvage operations, which are likely to begin this spring.

"While some people might wonder about the potential complexity of salvage at this depth, we have already conducted a thorough analysis of the best tools and techniques to conduct this operation and are confident that the salvage will be conducted efficiently and on a timely basis," said Greg Stemm, Odyssey's chief executive officer.

"Hundreds of modern cargo ships like this have been salvaged since the mid-20th century, some at depths of thousands of metres. We were fortunate to find the shipwreck sitting upright, with the holds open and easily accessible. This should enable us to unload cargo through the hatches as would happen with a floating ship alongside a cargo terminal."