Researchers have discovered a World War II-era German submarine nearly 70 years after it sank under a withering U.S. attack in waters off Nantucket. NBC's Brian Williams reports.

BOSTON -- Divers have discovered a World War II-era German submarine nearly 70 years after it sank under withering U.S. attack in waters off Nantucket.

The U-550 was found Monday by a privately funded group organized by New Jersey lawyer Joe Mazraani.

"They’ve looked for it for over 20 years,” Mazraani, a shipwreck diver, told The Boston Globe. “It’s another World War II mystery solved.”

In the second trip in two years to the site by the team, the seven-man crew using side-scan sonar located the wreck listing to its side in deep water about 70 miles south of Nantucket.

Sonar operator Garry Kozak said he spotted the 252-foot submarine during the second of an exhausting two days of searching. Kozak said the team asked him if they'd found it, then erupted in joy without a word from him.

"They could see it with the grin (on my face) and the look in my eyes," Kozak said.

The crew had searched 100 square miles of ocean, the Globe reported. Traveling at five knots, the ship scanned the vast expanse for signs of the sunken vessel, a tedious process crew members likened to “mowing the lawn.”

Mazraani dove down to confirm the discovery with pictures, the Globe said.

On April 16, 1944, the U-550 torpedoed the gasoline tanker SS Pan Pennsylvania, which had lagged behind its protective convoy as it set out with 140,000 barrels of gasoline for Great Britain, according to the U.S. Coast Guard website and research by Mazraani.

AP This sonar image provided by GK Consulting & AWS Expeditions/Joe Mazraani, shows a World War II-era German submarine U-550, found by a team of explorers Monday on the floor of the Atlantic Ocean 70 miles south of Nantucket Island, Mass.

The U-boat slipped under the doomed tanker to hide. But one of the tanker's three escorts, the USS Joyce, saw it on sonar and severely damaged it by dropping depth charges.

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The Germans, forced to surface, manned their deck guns while another escort vessel, the USS Gandy, returned fire and rammed the U-boat. The third escort, the USS Peterson, then hit the U-boat with two more depth charges. The crew abandoned the submarine, but not before setting off explosions to scuttle it. The submarine hadn't been seen again until Monday.

The U-550 is one of several World War II-era German U-boats that have been discovered off the U.S. coast, but it's the only one that sank in that area, Mazraani said. He said it's been tough to find largely because military positioning of the battle was imprecise, and searchers had only a general idea where the submarine was when it sank. Kozak noted that the site is far offshore and has only limited windows of good weather.

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The other team members were Steve Gatto, Tom Packer, Brad Sheard, Eric Takakjian and Anthony Tedsechi

Mazraani is cagey about the vessel's precise location, saying only that it's in deep water. Mazraani's said his best estimate was that the team spent thousands of dollars of its own money on the expedition. He joked that no one on the team, whose members range in age from the mid-20s to mid-50s, stands to make money from the find unless someone writes a book.

Mazraani said the next step is to contact any sailors or their families from the escort vessels, the tanker and the German U-boat to share the news and show the pictures. Another trip to the site is coming, he said, adding the investigation has just started.

"The history behind it all is really what drives us," Mazraani said.

This article includes reporting by The Associated Press.





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