The sonar “target” first appears as a green and yellow streak on Randy Holt’s computer screen. Up ahead, nothing can yet be seen through the dark water 700 feet below the ocean surface.

Holt’s submersible, Nomad, glides over the sandy bottom, fighting the current and searching. With each sonar sweep, the image grows more distinct on the screen. “Very good,” Holt says. “We’re real close to this thing.”

Then he spots something outside and switches off the lights: “See the shadow?” A large black silhouette emerges from the gloom. “Yeah,” Holt says. “This is our U-boat.”

Loading....

It’s the German submarine U-576, resting on its side, right where it sank in 1942. Its wooden deck plates have rotted away after 74 years underwater. But its hull, conning tower and deck gun — nicknamed “Peterle,” little Peter — are still there.

The encrusted hatches are all closed. And almost certainly entombed within are the skipper, Hans-Dieter Heinicke, and 44 German sailors, including one Herbert Sprissinger, who perished on his 20th birthday.

On 24 August, after a seven-year search, the National Oceanic and Atmospheric Administration (NOAA) got the first look at U-576 since the sub went down in a wild battle off North Carolina’s Outer Banks on 15 July, 1942.

NOAA’s Office of Ocean Exploration and Research, along with the University of North Carolina’s Coastal Studies Institute and the federal Bureau of Ocean Energy Management, had been looking for the sub since 2009 in the area where the battle had taken place.

With the help of sonar and other devices, it was found in August 2014. One of the merchant ships it sank in the battle had been found nearby the year before.

But last month was the first time anyone had actually seen the sub since it was shelled and depth-charged to the bottom that Wednesday in 1942, eight months after the United States entered World War II.

In partnership with a marine research outfit called Project Baseline, the University of North Carolina Coastal Studies Institute and SRI International, scientists made a series of dives from the 146-foot vessel Baseline Explorer.

Operating from within the thick plastic bubble of two-person submersibles, they studied the wrecks of the U-boat and its victim, the Nicaraguan freighter Bluefields, which had a huge torpedo hole in its side. (The crew of the freighter survived.)

On one dive Thursday, a reporter went along.

The Unterseeboot 576 rests about 35 miles east of here, out in the Gulf Stream, where German subs savaged merchant shipping during the war, sinking scores of vessels and killing hundreds of people.

It’s in 721 feet of water, well below the “crush depth,” where the enormous pressure would collapse its inner hull, NOAA experts said.

It’s an eerie, lonely place. The seafloor is barren. And the few fish around the wreck have a sickly gray pallor.

Inside the two and three quarters inch-thick sphere of the submersible, the only sounds were the whirring of the carbon dioxide scrubber, the occasional hiss of air, and Holt’s voice as he radioed depth and bearing to the surface.

“It’s sort of unreal,” said NOAA maritime archaeologist Joe Hoyt, the chief investigator on the project, who was among the first to glimpse the boat on Aug. 24.

“I knew the story, [but] the moment that we get in there and it comes out of the gloom at you . . . it was humbling,” he said.

At that great depth, the boat remains substantially intact. “It’s all there, just as it went down in 1942,” he said.

“One of the things we’re looking for is what happened to the crew,” he said. “Did they try to get out the escape hatches? Did the ship flood catastrophically? Were they on the seabed for some period of time, disabled with air still in the sub?”

“All the hatches we were able to see . . . were dogged down, closed,” he said. “So, you see those hatches closed and the moment you kind of see that . . . you’re immediately aware that it’s a tomb.”

“There’s 45 guys inside of that thing,” he said. “And no matter the exact circumstances of their demise, it had to just be horrifying.”

‘A dangerous situation’

On the afternoon of 15 July, 1942, Kapitänleutnant Heinicke had to make a crucial decision.

He was in a crippled, unlucky boat that had been damaged and nearly sunk by an aircraft attack a day or two before.

The attack had affected a ballast tank and hampered the boat’s ability to dive and surface. Heinicke had signaled his superiors that the boat could not be repaired.

“Under normal circumstances, that’s the end of the operation,” said retired National Archives expert and U-boat historian Timothy Mulligan. “If you can’t dive, or if you dive and you don’t know you’re going to come back to the surface . . . you’re in a dangerous situation.”

Heinicke was 29, the son of a German cavalry officer who had been killed on the Eastern Front in World War I. He was an experienced, observant commander who had been in the Navy for almost a decade.

He was on his fifth patrol with a year-old boat but had bagged only three ships and was plagued with engine trouble.

One of his victims, the armed British freighter Empire Spring, had gone down off Nova Scotia with all 55 hands aboard, according to the website Uboat.net.

Another, the Norwegian vessel Taborfjell, sank off Cape Cod so fast that only three of its 20-man crew survived.

But in the case of the American freighter Pipestone County, torpedoed off Cape Henry, Va., in April 1942, Heinicke surfaced near the lifeboats. He gave the survivors provisions and apologized for sinking the ship. There were no fatalities.

U-576 had a young crew. No one was older than 29, according to a crew list provided by NOAA. Seaman Egon Gablick was 18. Heinz Beckers, Kurt Bauer, Willi Steuer and Erwin Schlussler were 19.

World news in pictures Show all 50 1 /50 World news in pictures World news in pictures 14 September 2020 Japan's Prime Minister Shinzo Abe, Chief Cabinet Secretary Yoshihide Suga, former Defense Minister Shigeru Ishiba and former Foreign Minister Fumio Kishida celebrate after Suga was elected as new head of the ruling party at the Liberal Democratic Party's leadership election in Tokyo Reuters World news in pictures 13 September 2020 A man stands behind a burning barricade during the fifth straight day of protests against police brutality in Bogota AFP via Getty World news in pictures 12 September 2020 Police officers block and detain protesters during an opposition rally to protest the official presidential election results in Minsk, Belarus. Daily protests calling for the authoritarian president's resignation are now in their second month AP World news in pictures 11 September 2020 Members of 'Omnium Cultural' celebrate the 20th 'Festa per la llibertat' ('Fiesta for the freedom') to mark the Day of Catalonia in Barcelona. Omnion Cultural fights for the independence of Catalonia EPA World news in pictures 10 September 2020 The Moria refugee camp, two days after Greece's biggest migrant camp, was destroyed by fire. Thousands of asylum seekers on the island of Lesbos are now homeless AFP via Getty World news in pictures 9 September 2020 Pope Francis takes off his face mask as he arrives by car to hold a limited public audience at the San Damaso courtyard in The Vatican AFP via Getty World news in pictures 8 September 2020 A home is engulfed in flames during the "Creek Fire" in the Tollhouse area of California AFP via Getty World news in pictures 7 September 2020 A couple take photos along a sea wall of the waves brought by Typhoon Haishen in the eastern port city of Sokcho AFP via Getty World news in pictures 6 September 2020 Novak Djokovic and a tournament official tends to a linesperson who was struck with a ball by Djokovic during his match against Pablo Carreno Busta at the US Open USA Today Sports/Reuters World news in pictures 5 September 2020 Protesters confront police at the Shrine of Remembrance in Melbourne, Australia, during an anti-lockdown rally AFP via Getty World news in pictures 4 September 2020 A woman looks on from a rooftop as rescue workers dig through the rubble of a damaged building in Beirut. A search began for possible survivors after a scanner detected a pulse one month after the mega-blast at the adjacent port AFP via Getty World news in pictures 3 September 2020 A full moon next to the Virgen del Panecillo statue in Quito, Ecuador EPA World news in pictures 2 September 2020 A Palestinian woman reacts as Israeli forces demolish her animal shed near Hebron in the Israeli-occupied West Bank Reuters World news in pictures 1 September 2020 Students protest against presidential elections results in Minsk TUT.BY/AFP via Getty World news in pictures 31 August 2020 The pack rides during the 3rd stage of the Tour de France between Nice and Sisteron AFP via Getty World news in pictures 30 August 2020 Law enforcement officers block a street during a rally of opposition supporters protesting against presidential election results in Minsk, Belarus Reuters World news in pictures 29 August 2020 A woman holding a placard reading "Stop Censorship - Yes to the Freedom of Expression" shouts in a megaphone during a protest against the mandatory wearing of face masks in Paris. Masks, which were already compulsory on public transport, in enclosed public spaces, and outdoors in Paris in certain high-congestion areas around tourist sites, were made mandatory outdoors citywide on August 28 to fight the rising coronavirus infections AFP via Getty World news in pictures 28 August 2020 Japanese Prime Minister Shinzo Abe bows to the national flag at the start of a press conference at the prime minister official residence in Tokyo. Abe announced he will resign over health problems, in a bombshell development that kicks off a leadership contest in the world's third-largest economy AFP via Getty World news in pictures 27 August 2020 Residents take cover behind a tree trunk from rubber bullets fired by South African Police Service (SAPS) in Eldorado Park, near Johannesburg, during a protest by community members after a 16-year old boy was reported dead AFP via Getty World news in pictures 26 August 2020 People scatter rose petals on a statue of Mother Teresa marking her 110th birth anniversary in Ahmedabad AFP via Getty World news in pictures 25 August 2020 An aerial view shows beach-goers standing on salt formations in the Dead Sea near Ein Bokeq, Israel Reuters World news in pictures 24 August 2020 Health workers use a fingertip pulse oximeter and check the body temperature of a fisherwoman inside the Dharavi slum during a door-to-door Covid-19 coronavirus screening in Mumbai AFP via Getty World news in pictures 23 August 2020 People carry an idol of the Hindu god Ganesh, the deity of prosperity, to immerse it off the coast of the Arabian sea during the Ganesh Chaturthi festival in Mumbai, India Reuters World news in pictures 22 August 2020 Firefighters watch as flames from the LNU Lightning Complex fires approach a home in Napa County, California AP World news in pictures 21 August 2020 Members of the Israeli security forces arrest a Palestinian demonstrator during a rally to protest against Israel's plan to annex parts of the occupied West Bank AFP via Getty World news in pictures 20 August 2020 A man pushes his bicycle through a deserted road after prohibitory orders were imposed by district officials for a week to contain the spread of the Covid-19 in Kathmandu AFP via Getty World news in pictures 19 August 2020 A car burns while parked at a residence in Vacaville, California. Dozens of fires are burning out of control throughout Northern California as fire resources are spread thin AFP via Getty World news in pictures 18 August 2020 Students use their mobile phones as flashlights at an anti-government rally at Mahidol University in Nakhon Pathom. Thailand has seen near-daily protests in recent weeks by students demanding the resignation of Prime Minister Prayut Chan-O-Cha AFP via Getty World news in pictures 17 August 2020 Members of the Kayapo tribe block the BR163 highway during a protest outside Novo Progresso in Para state, Brazil. Indigenous protesters blocked a major transamazonian highway to protest against the lack of governmental support during the COVID-19 novel coronavirus pandemic and illegal deforestation in and around their territories AFP via Getty World news in pictures 16 August 2020 Lightning forks over the San Francisco-Oakland Bay Bridge as a storm passes over Oakland AP World news in pictures 15 August 2020 Belarus opposition supporters gather near the Pushkinskaya metro station where Alexander Taraikovsky, a 34-year-old protester died on August 10, during their protest rally in central Minsk AFP via Getty World news in pictures 14 August 2020 AlphaTauri's driver Daniil Kvyat takes part in the second practice session at the Circuit de Catalunya in Montmelo near Barcelona ahead of the Spanish F1 Grand Prix AFP via Getty World news in pictures 13 August 2020 Soldiers of the Brazilian Armed Forces during a disinfection of the Christ The Redeemer statue at the Corcovado mountain prior to the opening of the touristic attraction in Rio AFP via Getty World news in pictures 12 August 2020 Young elephant bulls tussle playfully on World Elephant Day at the Amboseli National Park in Kenya AFP via Getty World news in pictures 11 August 2020 French Prime Minister Jean Castex is helped by a member of staff to put a protective suit on prior to his visit at the CHU hospital in Montpellier AFP via Getty World news in pictures 10 August 2020 Locals harvest their potatoes as Mount Sinabung spews volcanic ash in Karo, North Sumatra province, Indonesia Antara Foto/Reuters World news in pictures 9 August 2020 Doves fly over the Peace Statue at Nagasaki Peace Park during the memorial ceremony held for the 75th anniversary of the atomic bombing EPA World news in pictures 8 August 2020 Anti-government protesters try to remove concrete wall that installed by security forces to prevent protesters reaching the Parliament square, during a protest against the political elites and the government after this week's deadly explosion in Beirut AP World news in pictures 7 August 2020 A protester throws a stone towards Israeli forces in the village of Turmus Aya, north of Ramallah in the occupied West Bank, following a march by Palestinians against the building of Israeli settlements AFP via Getty World news in pictures 6 August 2020 A woman yells as soldiers block a road for French President Emmanuel Macron's visit the Gemmayzeh neighborhood. The area in Beirut suffered extensive damage from the explosion at the seaport AP World news in pictures 5 August 2020 Damage at the site of Tuesday's blast in Beirut's port area, Lebanon Reuters World news in pictures 4 August 2020 A large explosion in the Lebanese capital Beirut. The blast, which rattled entire buildings and broke glass, was felt in several parts of the city AFP via Getty World news in pictures 3 August 2020 A general view shows the new road bridge in Genoa, Italy ahead of its official inauguration, after it was rebuilt following its collapse on August 14, 2018 which killed 43 people Reuters World news in pictures 2 August 2020 Empty stall spaces are seen hours before a citywide curfew is introduced in Melbourne, Australia EPA World news in pictures 1 August 2020 People take part in a demonstration by the initiative "Querdenken-711" with the slogan "the end of the pandemic - the day of freedom" to protest against the current measurements to curb the spread of COVID-19 in Berlin, Germany AFP via Getty World news in pictures 31 July 2020 Pilgrims circumambulating around the Kaaba, the holiest shrine in the Grand mosque in Mecca. Muslim pilgrims converged today on Saudi Arabia's Mount Arafat for the climax of this year's hajj, the smallest in modern times and a sharp contrast to the massive crowds of previous years Saudi Ministry of Media/AFP World news in pictures 30 July 2020 The Mars 2020 Perseverance mission lifts off at the Kennedy Space Centre in Florida. The mission is part of the USA's largest moon to Mars exploration. Nasa will attempt to establish a sustained human presence on and around the moon by 2028 through their Artemis programme EPA World news in pictures 29 July 2020 A woman refreshes herself in a outdoor pool in summer temperatures in Ehingen, Germany dpa via AP World news in pictures 28 July 2020 Malaysia's former prime minister Najib Razak speaks to the media after he was found guilty in his corruption trial in Kuala Lumpur AFP via Getty World news in pictures 27 July 2020 North Korean leader Kim Jong Un poses for a photograph after conferring commemorative pistols to leading commanding officers of the armed forces on the 67th anniversary of the "Day of Victory in the Great Fatherland Liberation War". Which marks the signing of the Korean War armistice KCNA via Reuters

The oldest on board was another kapitänleutnant, August Bohnenkamp, who would have turned 30 in November.

On the 29th day of the patrol, the damaged sub was headed east, perhaps toward home. Heinicke reported that he had made 16 miles, running on the surface in moderate seas.

“That’s the last communication,” Mulligan said.

At some point after that, the boat encountered an irresistible target.

It was an Allied convoy, designated KS-520 — 19 merchant ships and five escorts, bound from Hampton Roads, Va., to Key West, Fla.

Heinicke had spotted another convoy a few days earlier, but had lost contact with it.

He had also found one back in the spring, a group of seven troop transports. It was a potential feast for a U-boat. But he had been out of torpedoes and could do nothing.

Now he had to decide: Should he take the hobbled U-576 into battle or continue toward his home base in France?

“What does he do?” Mulligan said in a recent interview. “He tries to go after the convoy.”

Heinicke got into position and fired four torpedoes. Two hit and damaged the Chilore, an American freighter, according to NOAA. One hit and damaged the big Panamanian tanker J.A. Mowinckel, and the fourth sank the Bluefields.

But after firing the torpedoes, the U-boat inexplicably bobbed to the surface in the middle of the convoy. Patrolling airplanes and gunners on one of the convoy ships pounced.

The Navy seaplanes dropped depth charges, one of which slid off the sub’s hull before exploding, according to National Archives records Mulligan examined.

Debris flew up. The U-boat headed down, and black oil spread over the water.

Three days later, German headquarters asked U-576 to report. There was no reply. Headquarters tried to reach the boat again on 19 July and again on 21 July.

Nothing was heard.

‘Torpedo Junction’

Few people realize that desperate fighting raged just off the East Coast during World War II as U-boats torpedoed Allied shipping and U.S. forces fought back, NOAA said.

German subs sank 600 ships off the coast, often using the glow from U.S. towns to backlight their targets at night, according to historians.

The heavily travelled area off Cape Hatteras, N.C., was such a grim killing ground that it became known as “Torpedo Junction.”

It is what NOAA calls an oceanic battlefield. And the federal agency said it is working to determine exactly what happened there, just as historians would on a land battlefield.

NOAA is also considering expansion of its nearby Monitor National Marine Sanctuary, which protects the wreck of the famous Civil War vessel, to include the U-boat, the Bluefields and other historic shipwrecks in the area.

An estimated 90 vessels — including U-576 and three other subs — were sunk there between January and July 1942, NOAA said. And 1,600 men — 1,100 of them merchant seamen — were lost.

This week, the U-boat project had to be suspended because of bad weather, said David W. Alberg, supervisor of the Monitor sanctuary. He said the scientists hope to be back at the site this weekend.

The submarine is still technically the property of the German government, and the United States has agreed to care for it. NOAA’s aim is to conduct an underwater laser scan of both wrecks and produce exact 3-D models for posterity.

Last Thursday, as the submersible drifted through the dark water around the boat, Holt noted that the sub’s forward and aft dive planes were set as if the stricken vessel was struggling to surface.

It was one of the few outward clues to the sub’s end. There was also a patch of the outer hull that was peeled away near the front of the boat. Holt said that might be where a depth charge exploded, fatally weakening the structure.

It may have been that the crew sealed off flooded compartments but the boat was too heavy to rise, he said. “Maybe they just waited it out till the end,” he said.

An hour and a half after submerging, Nomad was cleared to ascend, and it slowly rose toward the surface and the sunlight, leaving U-576 behind in the dim underwater battlefield where it met its end.