Ocean exploration has always been salted with the allure of sunken treasure, and with precious metal prices hitting new records and new technologies allowing access to deeper sites, that Siren's call has never been greater. Recently, a team of Odyssey Marine Exploration (OME) technicians and archeologists announced finding not one, but two British shipwrecks off Ireland, the SS Gairsoppa and the SS Mantola. Only 100 miles and a World War apart, the two hulks rusting away in the deep Atlantic collectively contain what could prove to be millions of ounces of silver.

The bonus discovery of the SS Mantola, a mile and a half deep, came only two weeks on the heels of finding the SS Gairsoppa, which was the initially intended target. Both ships were sent to the bottom by German torpedoes, the Mantola in February, 1917, and the Gairsoppa in February, 1941. Mantola's cargo reportedly included 600,000 ounces of silver (worth about US$18 million today) while the Gairsoppa is reported to have carried upwards of 7 million ounces of silver as ingots (current value in excess of $200 million), along with 1,700 tons of now rather salty tea.

"The Mantola project is located at a depth range that we have a lot of experience in. We have information on the location of the cargo that should make this a great target for testing some new technology that will be useful for a number of new deep-ocean projects we have planned," said Odyssey CEO, Greg Stemm.

Treasure hunting has been big business for some time, as a visit to Tampa, Florida-based Odyssey's website will readily confirm. As the "low-hanging fruit" of shallower treasure wrecks becomes harder to find, technology employed by companies like Odyssey has advanced to allow access to deeper and deeper sites where billions in wealth still await recovery.

Those watery billions haven't escaped the scrutiny of cash-strapped governments, either. Last month, the UK government awarded Odyssey a lucrative salvage contract for the Mantola's cargo. Under the terms of the arrangement, 20 percent of whatever silver is recovered will go to enrich Her Majesty's treasury, while the lion's share goes to Odyssey, which is fitting since they footed all the upfront costs for the discovery, as well as all of the risk. The Gairsoppa recovery will proceed under a similar agreement.

"As we push deeper and deeper, a lot of new and interesting opportunities are presenting themselves" said Stemm. "This find shows the value of our research team and our extensive database of shipwrecks, which allow us to build backup projects that can be added to our surveys in the event of a quick find."

The Gairsoppa was located using a MAK-1M (deep-tow low frequency sonar system), aboard the chartered Russian vessel, RV Yuzhmorgeologiya. The site was inspected visually with a Remora Remotely Operated Vehicle (ROV) from the OEM vessel, Odyssey Explorer.

The 400-foot steel-hulled SS Gairsoppa, on return from India to Britain, left her protective convoy due to low fuel and was sunk by German submarine U-101. She eventually came to rest about 300 miles (483 km) southwest of Galway, Ireland in 15,000 feet (4,700 m) of water.

The 450-foot SS Mantola, also a British steamer, was less than a year old when she departed London, bound for Calcutta. She encountered German submarine U-81 about 140 miles off Fastnet Rock in southernmost Ireland, sank from her damage, and came to rest in over 8,000 feet (2,500 m) of water.

"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. Experienced treasure salvors with an impressive track record, OME discovered the Civil War-era shipwreck, SS Republic, in 2003 and recovered more than 50,000 coins and 14,000 artifacts. In May 2007, Odyssey salvaged a Colonial-era deep-ocean treasure site, code named "Black Swan," and recovered over 500,000 silver and gold coins, nearly 17 tons, in all.

Check out the Odyssey Marine Exploration footage of both vessels below:

Gairsoppa shipwreck footage

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