Chuck Cannon earned a bachelor’s degree in Naval Architecture and Marine Engineering from U-M in 1968. In late 1970, Cannon received an offer “only an idiot would refuse” from Global Marine, Inc.’s legendary chief engineer John Graham to work on the hull design for Glomar Explorer — an enormous deep ocean mining ship. Graham told Cannon he was being hired to work on an exciting “salvage” project. Later it was explained that the ship was for an audacious Howard Hughes-backed effort to mine manganese from the ocean floor.

Around the same time, GMI’s Klemme Jones, a U-M NAME alumnus from 1947, hired naval architect Charlie Canby, who began his close and still-continuing friendship with Cannon while both were students in Ann Arbor. One of Jones’ first instructions to Canby, who had just earned his U-M degree earlier that year, was to add an outsized “moon pool” at the bottom of Explorer.

Canby thought the specifications seemed odd, but he never questioned them. Later, when he learned the truth, the young engineer was shocked. “It was like hearing the facts of life for the first time.”

Why the Soviet nuclear submarine K-129 sank remains unknown. The sub missed a scheduled midnight radio check on March 8, 1968, as it crossed the 180^th meridian — and that was that. The Soviets became concerned about consecutive failed check-ins, and by the third week of March, when urgent communications went unanswered, the Soviets declared K-129, with 83 men aboard, “missing.”

U.S. intelligence services observed numerous Soviet subs, periscopes up, within their known patrol routes, which suggested a search might be underway. But the Soviets, who had not yet developed sea floor acoustic sensors, were using sonar — which made locating anything likely already resting on the ocean floor nearly hopeless.

The Soviets — unwilling to admit to these limited capabilities — quietly abandoned their search. They believed that no other foreign intelligence service would be able to find the sub, either. But the U.S. had in fact established a vast network of underwater microphones in the northern Pacific, which enabled them to identify the “sonic signature” of an implosion on March 8. This enabled Naval Intelligence to determine the site of the wreck in international waters nearly 1,600 miles northwest of Hawaii — at a depth of more than three miles.

In July 1968, the  U.S. Navy ordered the USS Halibut — the only specially equipped search submarine in its inventory — to find and photograph K-129. Using remote-controlled cameras, strobe lights, and sonar built to withstand extreme depths, Halibut had within three weeks not only located the sub but also generated enough photos to enable the CIA to determine that its missiles might still be intact — a potential intelligence cornucopia. But the CIA also knew, as revealed in a memo written at that time but not declassified, redacted, and released to the public until 2010, that the retrieval effort – named Project Azorian – would be no ordinary mission:

“Azorian…combined…advanced technological development, complex systems engineering and testing, unusually severe cover and security requirements, a demanding mission scenario in an unforgiving marine environment, the potential for a serious confrontation with the Soviet Union, a difficult and technically unusual exploitation phase, and a high cost...”

Yet it also was inevitable that the U.S. would pursue it. Since the late 1950s both countries had been engaged in dangerous and escalating gambles to gain military clues. It had become easier to identify and target land-based intercontinental ballistic missiles, so nuclear submarines were difference-makers. Submarine-based forays — and losses — were on the rise.

As then-CIA director William Colby said in a 1993 interview: This sub was not on some leisure cruise. “It was pointing missiles at us!”

By November 1969, the CIA’s rigorous due diligence had led them directly to GMI. With five heavy ocean-going drilling ships built in the last several years, including the largest ever, GMI had become the offshore drilling industry leader. But many aspects of this ship would constitute first-ever achievements. The core of the mission – hauling anything this heavy from this depth – had never been attempted. And it had to work the first time.

Most of those working on the ship’s design and construction were unaware, and would remain unaware, of its true purpose. This included as many as 11 U-M alumni – nine NAME graduates and two electrical engineers. Only those who needed to know were told, while the others believed the mining manganese cover story – as did most of the rest of the world.

John Hollett, a 1967 NAME graduate who returned to Ann Arbor to earn an MBA in 1971, was brought in to work on the ocean-mining side of the house. His job was to cultivate clients for GMI’s mining technology. This led him quite naturally to solicit the U.S. Navy, which nosed him too close to a certain secret CIA project. When word got back to his boss, Hollett was severely chastised—and brought in on the so-called “black” side of the mission.

“It became necessary for me to be ‘cleared’ to the actual salvage project since I could have compromised the whole thing by having come in a ‘back door,’” he said. To vet him, the CIA interviewed people from his past – friends, people he knew at U-M – even visiting some of his San Pedro neighbors in person. Posing as representatives for the Howard Hughes venture, they asked detailed questions about Hollett’s drinking habits, drug use, marital fidelity, and temperament.

“I remember people asking why Howard Hughes was so interested in my total being,” he said. “I feigned ignorance and said that was just what this guy was like.”

The University of Michigan’s program in naval architecture and marine engineering got its initial boost from an 1879 federal law that authorized the U. S. Navy to assign officers to engineering colleges around the country. When Mortimer Cooley, then an assistant engineer in the Navy, was detailed to the U-M in 1881, twenty-five students were enrolled in civil engineering. By the following year that number had ballooned to more than sixty.

Cooley stayed, eventually becoming the founding dean of the College of Engineering in 1915. He also recruited Herbert C. Sadler from the University of Glasgow, who arrived on campus in 1900 to make U-M’s NAME program “second to none in the United States.”

When plans were being developed in 1904 to build the West Engineering Building, Dean Cooley arranged for it to accommodate a naval testing tank – the first such tank owned and operated by an educational institution in the United States. The tank was promptly utilized for merchant ship research and for the design of vessels engaged in Great Lakes shipping. During World War II, it was used to develop floating dry docks, amphibious vehicles, and other small military craft.

The decade following the war brought rapid changes in marine technology, principally in the design and construction of ships for the bulk trade of raw materials. In 1957, when Richard B. Couch left his position as chief naval architect in the Navy Department’s Bureau of Ships to become NAME chair in 1957, he immediately implemented his ambitious plans for improving the scope of the educational program and the capabilities of the tank.

By the early 1970s the University of Michigan – with a strong and growing reputation and a curriculum emphasizing theory in analytical matters and economic imperatives and creativity in its design courses – was producing about two-thirds of all the U.S. graduates in naval architecture and marine engineering.

Just a few years earlier, Cannon, Canby, Hollett, and their fellow NAME students were enjoying Ann Arbor campus life. Most were members of the U-M Sailing Club, or of the Quarterdeck Society – a social club for serious NAME students that required publication of a technical paper prior to entry.  NAME was a close-knit department, led by well-liked professors Couch and Henry Benford. The campus was rife with anti-war protests and other tumult, but these young men did not get caught up in much of that. Most spent large portions of their time working in the drafting room in the West Engineering building – drawing, performing slide rule calculations, and just hanging out.

Now all were immersed in a dangerous covert CIA operation.

But not everyone was cleared, including Steve Kemp, a GMI naval architect and 1970 NAME graduate. Most assumed Kemp’s non-clearance was due to his well-known anti-Nixon stance. But Kemp was talented and valuable enough to remain on the project. He would just need to be shielded from certain information, which Kemp sometimes found peculiar.

When Chuck Cannon finally was briefed on the “cloak and dagger stuff” – the “white” manganese mining story as cover for the “black” CIA operation to recover a Soviet nuclear sub – it “opened up a whole new world of secrecy” that required him to keep information even from his wife, which made him “personally uncomfortable.”

Howard Hughes – notoriously rich and eccentric – had agreed to lend his name and otherwise stayed away. But his representatives served in a variety of roles to extend and deepen the cover story, with each milestone – arrivals and departures from various ports; a celebratory signing to transfer the ship’s title from GMI to Hughes – glamorized by a dedicated public relations shop feeding very real-seeming tidbits to an all-too-willing press. Some crewmen even mined for actual manganese nodules and posed dockside, with buckets of their bounty, for photos that were splashed across newspapers worldwide.

Adding to the mission’s degree of difficulty was that the Soviet sub went down in one of the roughest sections of open water on the globe. The retrieval operation would therefore need to take place within a narrow six-week good-weather window – July through mid-September– while the effect of roiling waters would still be carefully accounted for in a variety of ways.

Explorer featured three major elements: the vessel Explorer; the heavy-lift pipe string; and the sub-sea grapple “claw.” Nicknamed Clementine, the claw – once lowered on the pipe string to the ocean floor – would grasp the wreckage and lift it up through the moon pool.

That moon pool – an enormous center well opening in the hull where the captured sub would be stored, away from view – worried chief architect Graham to no end. It was so large when opened that only very narrow sidewalls remained to hold the bow to the stern.

As Explorer’s specifications were fine-tuned, Cannon was charged with periodically measuring how stable the ship would be with the moon pool fully opened and flooded. His latest computations were showing the vessel with practically zero stability when lifting the sub off the ocean floor.

When Cannon gave Graham the news, he “exploded.” Not only had the steel for the ship already been cut and mostly assembled, but the “company” (i.e., the CIA) would need to be told. Graham grabbed Cannon and flew to Langley Air Force Base, where Graham did all the talking. This was a serious stability issue. The only solution was to widen the ship.

The quick decision that followed – to widen the ship by 10 feet – meant a nearly complete redesign. But its even greater impact was that Explorer would now be too wide to make safe passage through the narrow Panama Canal as it journeyed from its construction home in Chester, Pennsylvania, to Long Beach, California, where a new crew would prepare for the Pacific Ocean mission. The Explorer would have to go all the way around the southern tip of South America to get there.

The pipe string was not mechanically complex. But its stresses and loads were making mere mortals cringe. A 1970 CIA task force called it “impossible” to manufacture a pipe string strong enough to support the mission’s estimated maximum fail-safe load of more than 17 million pounds. GMI convinced them otherwise, prevailing upon the CIA to build an expensive customized full-scale system capable of supporting a load of more than five million pounds in excess of that estimate.

Clementine’s design was asymmetrical, to accommodate both how the sub was situated and how it would therefore need to be grabbed from the bottom of the ocean. No less an expert than Kelly Johnson — the U-M engineering alumnus and Lockheed Skunk Works icon whose previous CIA work included designing the U-2 and the Blackbird spy planes — was consulted for his review and blessing of the design.

The sub’s capture was to be accomplished through remote manipulation of the claw by crewmen needing a clear picture of the wreckage and its surroundings — from three miles above. One CIA engineer offered this analogy:

Imagine standing on top of the Empire State Building with a 4-by-8 grappling device attached to the end of a one-inch-diameter steel rope. The task is to lower the rope and grapple to the street below, snag a compact-sized car full of gold and pull the car back up to the top of the building…without anyone taking note….

Two hundred and fifty engineers, 20 purchasers and more than 3,000 production workers were working all day, every day, to meet the ship’s rigorous timetable. It was a “pure muscle project” whose costs — projected to exceed $50 million and perhaps approach $100 million at a time when the average ship cost was only $12 million — were considered extreme.

Yet even as this costly, break-neck pace was beginning, skepticism lingered within Navy ranks that this crazy plan would work. The Chairman of the Joint Chiefs worried about the mission’s then-estimated 20-30 percent chance of success — not to mention the nature of a Soviet response should they find out.

On July 24, 1973, Explorer began its journey from Chester’s Atlantic coast to Long Beach’s Pacific coast – the long way around. The ship would travel 12,745 nautical miles in 50 days, seven hours, and 30 minutes, including a short layover in Bermuda and a brief stop in Chile.

When Explorer arrived in Long Beach on Sept. 30, it pulled into its pre-arranged berth alongside Howard Hughes’ famous Spruce Goose flying boat – another cover story masterwork.

And now it was time to convert the rest of the crew from “white” to “black.”

After working for a short time with Graham and Cannon, Canby had left GMI for a short time for a job he thought he’d love – but hated. When he returned he “just wanted to be on a boat,” so he had joined the crew in Bermuda as a “regular seaman” – still believing he was on a great adventure to mine manganese.

Now Canby, who originally was told a cover story “so thick and thorough, it was believable to anybody,” arrived in Long Beach, where he learned “the facts of life” – which was eye-opening enough. But Cannon, for family reasons, would not be staying on to complete the mission, and Kemp still couldn’t get clearance. So Canby suddenly was named the naval architect – on a ship whose secret mission was to find and recover a Soviet nuclear submarine.

Time was running short, and adding to the stress and tension was Graham’s poor health. A lifelong smoker, the tough but beloved leader suffered from chronic emphysema. In the fall of 1973, Graham received a cancer diagnosis. He remained at work but was so weak that Kemp had become his special assistant, making inspections and performing tasks that Graham no longer could. Though it was especially awkward, in those circumstances, to keep the truth from Kemp – they all did.

Sea trials finally began in January 1974, and they did not go well. The pipe handling and heavy-lift system worked, but not especially smoothly. It soon became clear that there likely would be breakdowns, but they would just have to be fixed on the move. Nothing could simulate actual operational conditions except the real thing.

On June 7, 1974, President Nixon officially authorized the mission – with the caveat that recovery operations not begin until after the president returned from his long-planned June 27-July 3 visit to the Soviet Union.

Explorer arrived at the recovery site on July 4, one day after Nixon’s return to the United States.

During much of the time that Explorer floated above its target, awaiting calmer seas and readying for the sub’s capture, a Soviet missile range instrumentation ship, an SB-10 tugboat, and a companion helicopter all lurked close enough to take photos.

Explorer crewmen at times exchanged messages with the instrumentation ship and calmly conveyed its white program “realities.” The Soviets at one point transmitted, “We wish you all the best,” and appeared to leave the scene.

The next day, however, the tug reappeared and circled close enough that Explorer had to warn it off more than once. With the tug remaining nearby, the heavy lift crew very slowly lowered Clementine toward the bottom, where its cameras finally found and started to take surprisingly clear photos of the target.

With extreme caution, operators situated the claws around the sub. And on Aug. 1, just as they were starting to actively grab it, the Soviet tugboat gently drifted elsewhere.

The claw was designed to dig beneath the sub to ensure its complete capture. But the soil was harder than anticipated. As the crew, with some nervousness, tried its best to close around the entirety of the sub, the ship began to list.

The crew surrounded their catch with a containment net and paused. Their next step would be their most dangerous. If the pipe broke, the Explorer could split in two.

The upward hauling went well at first. The coveted sub had risen more than 9,000 feet. And then….

“You kind of know how it’s going on the outside by how you feel in your seat,” GMI engineer Sherman Wetmore said. And it felt to him like a “small earthquake” – like “something had gone wrong somewhere on the ship.”

Clementine, indeed, had dropped most of its quarry – about two-thirds of the submarine. “But we still had a piece of it, so keep comin’,” Wetmore thought.

Parts of the sub had shaken loose and were floating into the moon pool, and the crew worried the Soviets might notice. But, as if on cue, the tug floated away once more. Heavy lift operators grabbed the opportunity to quickly reel in the remainder.

With Clementine back in the ship’s hull and the moon pool gates securely closed, GMI heavy lift engineer Charlie Johnson was moved by the sight of the recovered sub, resting serenely in the moon pool.

“We did it!” he said.

Aboard Explorer, the crew was inspecting and cataloging salvaged property, and specially trained hazardous materials personnel handled potentially radioactive remains. Upon its arrival in Lahaina, Hawaii, where the crew—in need of a well-deserved rest—would give way to replacements, the Honolulu Advertiser ran a page one story, lauding Howard Hughes’ manganese-mining exploits.

Explorer crewmen confirmed that several of Clementine’s claws fractured as the recovered wreckage was pulled into the hull.  Whatever the cause of the incomplete capture – the engineers had numerous theories – the recovered section was reported to have included two nuclear torpedoes, as well as instruments, sonar equipment, codebooks, and other material of interest. Years later, the CIA – while remaining coy about the full extent of its bounty – publicly hailed the mission as “one of the greatest intelligence coups of the Cold War.”

At first, it was thought that the Soviets had been tipped off. But its intermittent lurking later was believed merely to be part of its ordinary Pacific fleet operations. Even had there been advance warning, however, the Soviets didn’t know K-129’s location. And its military command, long believing recovery impossible, was just as prone to disbelieving intelligence to the contrary.

The radioactive remains of six Soviet submariners – one still in his bunk, reviewing a log – also were recovered. These crewmen were accorded a memorial service, with military honors, before being buried at sea. The CIA’s film of the entire operation remains classified, but the burial at sea portion was declassified and provided to the Russian government, along with K-129’s recovered bell, as part of a 1992 diplomatic effort.

When Explorer returned to Long Beach in September 1974, rumors floated that it would be going back out. Charlie Canby, who called it “the best job I could have,” was excited about the prospect – though apparently some of the heavy lift operators were not as interested. “The intenseness was too much,” said GMI heavy-lift operator Johnson.

What few knew, though, was that rumors were becoming reality. The CIA had prepared a cleanup mission, dubbed Matador, to retrieve what had been left behind.

The Explorer’s mission became public in 1975 when, after rejecting repeated pleas from CIA Director Colby to suppress his reporting, journalist Jack Anderson broke the story, saying he did so because “Navy experts have told us that the sunken sub contains no real secrets and that the project, therefore, is a waste of the taxpayers’ money.”

Anderson’s front-page story in the Los Angeles Times derailed Matador. With the cover now blown, many – especially Kemp – felt duped. But now all those strange details he had puzzled over suddenly made sense.

Among those most disappointed was Canby.

“We took Clementine off the ship, put new grabbing arms on it, and brought it back onboard,” Canby says. “We would go out and test the heavy lift system and it would work so smoothly. Everything was just humming. We were all prepared to go out the next summer.”

Though Canby would later go on to other adventurous seafaring projects in his career, this one was not to be. Explorer instead was mothballed for more than two decades in the north end of San Francisco Bay. In 1996, its specialized mission components were stripped and the ship was leased for deep ocean mining until Explorer finally was retired and scrapped for parts.

In 2006 the American Society of Mechanical Engineers honored Hughes’ Glomar Explorer with the prestigious Landmark Achievement Award, declaring it among the outstanding engineering feats of the 20^th century.

Explorer was based on “the sound application of engineering principles,” Canby says. “The mass and size – that could be done again. But no one builds ships that large [anymore]. This was a total one-off.”

Sources include The Taking of K-129: How the CIA Used Howard Hughes to Steal a Russian Sub in the Most Daring Covert Operation in History, by John Dean; CIA: Official History (de-classified and redacted, 2010); An ASME Historic Mechanical Engineering Landmark, Houston, Texas (July 20, 2006); Project Azorian: The CIA and the Raising of the K-129, by Norman Polmar and Michael White; Azorian: The Raising of the K-129, Michael White Films; The CIA’s Greatest Covert Operation: Inside the Daring Mission to Recover a Nuclear-Armed Soviet Sub, by David Sharp

An earlier version of this story was published by the College of Engineering.