The 619-foot-long Hughes Glomar Explorer attracted plenty of attention in 1974. The American deep-sea mining vessel, said to be the brainchild of eccentric billionaire Howard Hughes, was one of the largest ships of its kind, so girthy it couldn’t even fit through the Panama Canal. But it wasn’t the ship’s size that led to widespread interest; it was its mission. Hughes was going to do the unthinkable with it: mine manganese nodules right from the ocean floor.

So, when the Glomar sailed 1,800 miles northwest of Hawaii in a vast ocean wilderness toward the Soviet Union, people took notice—including members of the Red Fleet. As Soviet ships cruised by the Glomar, they had no clue what the ship’s real mission was.

In fact, few did.

That’s because the mining vessel wasn’t really part of an effort to mine manganese nodules from the ocean floor—that was just the cover story. Instead, Glomar was involved in a secret CIA mission dubbed “Project Azorian.” The goal? To use the ship’s hidden internal hydraulic system to drop a claw 16,500 feet into the depths of the Pacific to pull up a lost Soviet nuclear submarine thought to be full of nuclear-armed ballistic missiles and untold Cold War secrets.

k129 submarine
CIA
The Golf II-class ballistic missile submarine K-129, hull number 722, sank in 1968. It was carrying three SS-N-4 nuclear-armed ballistic missiles.

The cover story was fantastically complicated, a truly cheeky attempt from the CIA to make the Glomar expedition look ridiculously wild, but for all the wrong reasons. “With something like this you need to keep the circle of secrecy really small,” Andrew Hammond, International Spy Museum historian and curator, tells Popular Mechanics. “It would be ‘need to know.’ Even if you know something, you maybe don’t know everything. You have to get far up the food chain to get the whole picture.”

That picture starts with knowing that the Soviet K-129, a Golf II-class nuclear submarine, sank in 1968. It was clear from American intelligence that the Soviets were unsure exactly where the ship went down, having spent two months searching in vain for the lost submarine and its 98 crew. But thanks to sophisticated acoustic tracking, the United States had a clear picture of where the sub sank. It would take the U.S. six years to devise a mission, craft the necessary equipment, and sail the Glomar to the site to secretly attempt to pull the sub up from the ocean floor.

“This is a long period of time,” Hammond says of the project. “Think of planning an operation of that magnitude, a ship, a cover story, Howard Hughes.” Indeed, the Spy Museum in Washington, D.C. where Hammond works has artifacts from the event including actual whiteprints of the ship building to coveralls from the Glomar crew with unique stitching. “The level of detail is pretty incredible,” Hammond says. “It was all to make it appear it was something it wasn’t.”

In July 1969, the real work began. The CIA enlisted Hughes’ help—few would doubt the billionaire’s desire to publicly back a mission to build an oversized mining vessel and send it into the Pacific in search of manganese nodules—and then made a public spectacle between 1971 and 1972 of building the Hughes Glomar Explorer. Articles in trade publications detailed the real-life events of everything from the shipbuilding location in Chester, Pennsylvania, to sailing the mining vessel through the Strait of Magellan in South America because the mammoth ship couldn’t fit through the Panama Canal.

“The level of detail, the size of operation, and audacity of operation was pretty incredible,” Hammond says. “It took years of patient work. This is an example of playing the long game. Just the timing and logistics, there is so much going on there, the number of things you would have to think about would be incredible. The stakes are really high, you are essentially stealing a Soviet submarine from the bottom of the ocean.”

view of the hughes mining barge
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This archival image circa 1976 depicts the Glomar’s 179-foot-long “Underwater Transfer Platform,” as the public knew it at the time. The barge master had refused to divulge the purpose of the UTP, but did say that, hypothetically, it could be used in the recovery of a submarine. Today, we know the UTP as Project Azorian’s capture vehicle.

By October 1970, CIA engineers and government-cleared contractors determined the only way to lift the submarine was a heavy-duty winch mounted on a specially modified ship. The keel of the ship was laid in November 1971, and the Glomar construction required specially designed machinery thanks to its size. The resulting ship resembled an oil-drilling derrick, but one that included a pipe-transfer crane, two tall docking legs, a claw-like capture mechanism, and a center docking well known as the “moon pool” with doors to open and close the well’s floor.

“The patriotism was unbelievable and there was a lot of pride in keeping things secret,” Sherman Wetmore, a lead engineer on the Glomar, later told the CIA. “There was a lot of respect on both sides, CIA admired the engineers’ work ethic, and contractors respected the security preparations and thoroughness of the CIA.”

The Glomar made its way to Long Beach, California for additional pre-mission prep work. That included loading 24 vans containing classified equipment for the mission onto a barge. The barge then dipped underwater under the cover of night and loaded equipment—plus the steel piping and claw capture vehicle that could lower from the underbelly of the ship—via the moon pool to keep the entire process away from prying eyes on nearby ships or Soviet satellites.

“The stakes are really high, you are essentially stealing a Soviet submarine from the bottom of the ocean.”

Once finalized, the Glomar set sail toward the submarine wreck site, arriving on July 4, 1974, purposefully starting the day after President Richard Nixon returned from a trip to Moscow, as part of his agreement to signing off on the mission. The nearly 200 crew members—all clad in specially designed Glomar gear, from patches on the apparel to belt buckles—then spent weeks in a recovery mission, eventually hovering over the exact wreckage spot and lowering the capture vehicle by extending 60-foot sections of supporting steel pipe one piece at a time.

“Imagine you are on the ship, and you see the Soviet ships coming and looking at what you are doing, taking photographs, and looking at you through binoculars,” Hammond says. “That would be disorientating, I’d guess. You could never rule out that something bad would happen.”

With any U.S. Naval protection days from the Glomar, Soviet ships monitored the crew, including a tug that stayed onsite for two weeks, at one point getting as close as 200 yards. A Soviet helicopter circled the Glomar and the ship’s crew stacked crates on the ship’s helicopter deck to keep the Soviets from landing. A redacted CIA document says orders were given to “be prepared to order emergency destruction of sensitive material which could compromise the mission if the Soviets attempted to board the ship.”

project azorian capture vehicle diagram
CIA
Project Azorian’s capture vehicle, a sub-sea grapple claw, was nicknamed “Clementine.” The claw has survived to this day, even aiding in the Francis Scott Key Bridge recovery effort in Baltimore.

As waves battered the Glomar, the crew lowered the capture vehicle and straddled the 132-foot-long sunken submarine. Once lowered to the ocean floor with the pipe assembly, the capture vehicle snatched at the submarine’s hull. Slowly and steadily, it worked in reverse, pulling up the entirety of the submarine.

It was all going to plan. Until it wasn’t.

Roughly halfway back to the surface—about 9,000 feet from the ocean floor—the submarine broke apart, with the front 100 feet of the sub dropping back to the floor. The crew kept going, eventually pulling a portion of K-129 into the Glomar.

“Why the claw broke has continued to haunt me,” Wetmore told the CIA.

It took the crew eight days to winch the submarine up. In August 1974, they took a portion of the recovered submarine to Hawaii for examination. The exact contents haven’t been declassified like the larger project scope was, although the CIA says that six bodies were given a formal military burial at sea.

Six years in, Project Azorian hadn’t accomplished its grand plan, completing only a portion of the effort. As plans started for a second mission, the secrecy of the Glomar started to unravel.

In an unrelated event, activist thieves broke into Hughes’ Los Angeles office, gaining access to secret documents that tied the businessman and the Glomar to the CIA. Amidst efforts to keep the news from reaching the public, some reporters willingly sat on the story. That changed in February 1975, when the Los Angeles Times connected Hughes and the CIA to the Glomar, blowing up the secrecy of the mission and leading then-President Gerald Ford’s administration to distance itself from any further mission. It also allowed the CIA to trot out the now-famed “can neither confirm nor deny” phrase.

“Although Project Azorian failed to meet its full intelligence objectives, CIA considered the operation to be one of the greatest intelligence coups of the Cold War,” the agency wrote in a blog post. “Project Azorian remains an engineering marvel, advancing the state of the art in deep-ocean mining and heavy-lift technology.”

glomar explorer
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The Glomar in 1978. Despite its original mission having nothing to do with deep-sea mining, the ship would go on to live a second life advancing that industry. Throughout the course of an 18-year drilling career, the Glomar worked in the Gulf Of Mexico, Nigeria, the Black Sea, Angola, Indonesia, and India with a number of oil companies.

Hammond says that while the Soviets were known to fight the Cold War with human intelligence, America excelled at technical intelligence, with the Glomar being the largest and most public example.

The Glomar went on to lead a less secretive life, handling a few ocean mining voyages before going decades without use. In the 1990s, a petroleum company restored the ship, then known as the GSF Explorer, for deep-sea oil drilling and exploration until it was finally scrapped in China in 2015.

One item that didn’t reach the scrapyard was a deck plank pulled off the Glomar in the 1970s. The CIA planned to present it to Nixon as a memento of his backing the mission, but before the CIA could present Nixon the plank, he resigned. The plank—along with a variety of Glomar-related items—now reside in the museum, a symbol of a mission that never fully reached its potential.

“We don’t know exactly what intelligence was and wasn’t gleaned,” Hammond says. “That may be something for further down the line.”

Headshot of Tim Newcomb
Tim Newcomb

Tim Newcomb is a journalist based in the Pacific Northwest. He covers stadiums, sneakers, gear, infrastructure, and more for a variety of publications, including Popular Mechanics. His favorite interviews have included sit-downs with Roger Federer in Switzerland, Kobe Bryant in Los Angeles, and Tinker Hatfield in Portland.