A Silent Guardian Still on Patrol

Thresher prepares for launch in Portsmouth on July 9, 1960. Courtesy National Archives and Records Administration

On April 15, the annual memorial of the Thresher’s sinking was held to acknowledge the lost submarine and honor the 129 men who perished with it 60 years ago in the deadliest submarine disaster in U.S. history. The Thresher was built and commissioned at Portsmouth Naval Shipyard (PNSY) and sank some 220 miles off the coast of Cape Cod on April 10, 1963. Five large sections of the submarine lie among acres of debris just over the continental shelf, in 8,400 feet of water.

The loss of the men on Thresher is still an open wound in the local and military community. The 60th memorial was held at a high school in Kittery near the Portsmouth Naval Shipyard. Attendees included U.S. Navy veterans of past generations, representatives of PNSY and surviving family members of the men who perished aboard Thresher, as well as U.S. Sens. Jeanne Shaheen and Maggie Hassan.

Bruce Harvey, the son of Lt. Cmdr. John Wesley Harvey (who was the commanding officer of Thresher when it was lost during sea trials), shared memories and emotions with those in attendance.

“In September of 1946, my father was sworn in as a midshipman,” Harvey said. “The last day I saw my dad was when our family went to church on Palm Sunday, April 7, 1963. On the evening of April 10, at approximately 8 p.m., the Navy notified my family that radio communication with Thresher had been lost. My mother put us to bed, assuring us that maybe the submarine was still OK. Then at 9:30 a.m. the following morning, the secretary of the Navy informed us about the loss of the vessel.”

A somber mood reverberated as a bell was rung 129 times while a slideshow featuring photographs of each of the fallen flashed across the screen onstage. But much of the emotion felt by those attending was summed up in Harvey’s words: “I believe that the loss of the Thresher was a preventable accident. That being said, profound, meaningful changes occurred with the SUBSAFE program.” (SUBSAFE is a 1963 quality assurance program that assures that submarine hulls will stay watertight and can recover from an unanticipated flooding casualty.)

Since September 2020, the Navy has released over 3,000 pages of documents and exhibits that address the tragedy. The public can now view these, thanks to a Freedom of Information Act lawsuit filed with the Navy by retired Captain James B. Bryant. These documents and exhibits can be viewed on the Secretary of the Navy Reading Room website, along with interviews of those involved with Thresher. 

Documents reveal that, prior to the final sea trials for Thresher, there was a “fast cruise” (when all of the submarine’s systems are tested while the vessel is secured “fast” to the dock) scheduled for March 24 and 25 of 1963. During the 56th annual memorial, Betty Stephenson, the sister of one of the crew, spoke about her brother’s reaction to that fast cruise. “On Feb. 4, 1963, my brother, Richard William Jones, was assigned to the USS Thresher,” Stephenson said. “Unfortunately, all of us here today share in the ‘rest of the story’ in one way or another.” She says her brother came home early and had explained to his mother, “We did mock (sea) trials, and if we’d been at sea, we would have sunk.” The family wasn’t concerned, said Stephenson, “because after all, the USS Thresher was the newest, the biggest and the best.” To get a sense of how impressive a ship she was, picture the USS Albacore, on display off Market Street Extension in Portsmouth, and add another 70 feet to its hull.      

Thresher at sea on July 24, 1961. Courtesy National Archives and Records Administration

Thresher was launched from PNSY on July 9, 1960, and commissioned on Aug. 3 of the next year — a short turnaround, according to veteran submariners and engineers. Admiral Hyman G. Rickover, widely known as the Father of the Nuclear Navy, may have hastened the process, having made clear his preference for nuclear (over diesel) submarines — although, to his credit, he accompanied many vessels himself during sea trials — and the increased complexity of the systems aboard a nuclear-powered submarine may not have been given adequate consideration.

Steve Walsh, a University of New Hampshire graduate with knowledge of SUBSAFE research and firsthand experience aboard sea trials, explained how when a submarine at depth suffers a leak, it is often extremely hard to locate.

“A flooding casualty in a submarine at depth can be in the form of a mist,” Walsh said. “Or it can originate in one part of a compartment, rebound off walls and behind equipment, and appear to be entering from a completely different angle. In any case, the flooding casualty can be difficult to locate in a timely manner, which can be catastrophic if the submarine is gaining weight and having issues achieving positive buoyancy, through purging the ballast tanks or driving to the surface.”

Walsh said while the story of Thresher is undeniably tragic, it illustrates the pressures — both physical and political — endured. “It shows how political and military pressures of the day, driven by the intensifying Cold War, undermined the time required for the proper design of that class, of which Thresher was the lead ship,” Walsh said. Which is not to understate the extensive preparation that the submarine underwent on its way to duty. The initial Thresher document release features a Q&A between the 1963 court of inquiry and U.S. Navy Captain William E. Heronemus, the shipbuilding and repair superintendent at PNSY in 1963.

“We worked on 875 different job orders,” Heronemus told the court of inquiry in 1963. “Two different (job orders) totaled as much as 6,000-man-days work of effort each. Relevant work a hull integrity surveillance inspection and improvements in the variable (ballast) tanks.” Other late modifications that took place close to sea trials included the installation of PUFFS (Passive Underwater Fire Control Feasibility System) sonar, used for long-range passive detection of targets and other weapons.

“The Thresher class was built around the torpedo-tube-launched SUBROC ballistic missile with a nuclear warhead,” said Bryant in an October 2022 interview. “The missile … needed PUFFs to get a reasonably accurate range for it to be effective.”

Questions that haunt those who study the loss of the Thresher are many: Was silver brazing technology versus welding a facilitator of catastrophic flooding casualty onboard Thresher? Brazing was cheaper and more expedient in bonding joints, such as the ones in high-pressure water systems onboard submarines. Were there issues with the ballast tanks on Thresher? Ballast tanks give submarines positive buoyancy when high pressure air forces out the water. With Thresher, there have been questions about the orifice and strainers between the main ballast tanks, and the high-pressure air tanks used to blow water out of the ballast tanks.

“Ruptured strainers (between the high-pressure air and water ballast tanks) would be less restrictive than collapsed strainers,” Walsh said. “And orifice plates significantly restricted air flow to the MBTs.” Certain “conical” strainers used were retained by request of the new commanding officer of Thresher.

“(I believe) this was fatal, as they were never intended to be retained, as they adversely affected the air flow of the high-pressure air system,” Walsh says, noting it’s also possible that moist air and its expansion might have caused these strainers to collapse and then ice over, choking off the air flow to the main ballast tanks and Thresher’s attempt to blow sea water out of them to regain positive buoyancy.

The key question remains: Why was Thresher not able to drive to the surface? 

When a submarine’s nuclear reactor shuts down, excess steam can be used to power the vessel. Why this did not occur is still being debated. Why were the last radio transmissions from Thresher to the rescue/escort ship Skylark not consistent with a vessel being under duress? 

Thresher is memorialized at Arlington National Cemetery, close to the monument for the Space Shuttle Challenger. Courtesy National Archives and Records Administration

Captain Bryant showed how the reported radio transmissions between Skylark and Thresher aligned with SOSUS underwater recordings of the event. (The Sound Surveillance System, or SOSUS, is a multibillion-dollar network of hydrophone arrays mounted on the seafloor throughout the Atlantic and Pacific). Bryant referenced an underwater telephone report beginning at 0913 hours.: “Experiencing minor difficulties…Have positive up angle…Am attempting to blow up…Will keep you informed…”

The low-key reports are now baffling. “The Thresher’s difficulties were by no means ‘minor’ at 0913,” Bryant said. “An up angle was expected to enable the Thresher to go shallow. ‘Have positive up angle’ implies that the submarine had recovered from a dangerous down angle. The report of ‘attempting to blow up’ confirms that the ballast tank’s blow was ineffective.”

At 0918.4, SOSUS and the Skylark detected hull collapse at a calculated depth of 2,400 feet, 450 feet below the potentially deadly “crush depth” of 1,950, creating a bubble pulse that registered an energy release equivalent to 22,500 pounds of TNT.

Crew inexperience is often discussed. There was a 30% turnover of the Thresher crew prior to the April sea trials, and many of the crew were diesel — versus nuclear — certified.  

The space race with the Soviets and the Cuban Missile Crises both had fueled the push toward submarine deployment. Messages from the Navy’s higher command at the time reveal the sense of urgency to have the vessel deployed. 

In 2018, CNN confirmed another interesting aspect about the legacy of Thresher.  

 Dr. Robert Ballard of the Woods Hole Oceanographic Institute, himself a Navy reserve officer, was granted U.S. Navy support in 1985 to search for Titanic. There was a condition, however. At the Navy’s request, Ballard would locate and survey the wreckage of Thresher and another nuclear submarine, Scorpion. Military authorities wanted to know not only if there was a threat of nuclear contamination to the ecology, but also if there was any evidence that the Russians had surveyed the wreckage of both submarines already.

Ballard described the impact of his first view of Thresher. “There is that initial feeling of excitement,” Ballard says. “Then it strikes you that something really bad happened here.”

Kevin Galeaz of USSVI Thresherbase — an organization that preserves the memory of those who perished on the Thresher and their families — and his team were the driving force in the establishment of the Thresher Memorial at Arlington National Cemetery. Touchingly, for Granite Staters, the monument is located close to that of the Space Shuttle Challenger; NASA has since corresponded with the Navy and SUBSAFE technologies in order to make space vehicles safer. 

Out of tragic darkness, a hopeful light can reveal itself. Through the subsequent research and development of SUBSAFE technology, submarines are safer due to lessons learned from the Thresher disaster. No SUBSAFE-certified vessel has been lost since the tragedy of Thresher. 

A strong Navy with worldwide capabilities is as important now as ever. One would hope that vessels and equipment — and personnel — are not deployed ahead of their readiness. Although 129 men perished on April 10, 1963, they continue to serve on eternal patrol.

The USS Thresher, painted by artist C.G. Evers, commissioned by the U.S. Naval Institute Collection. Courtesy National Archives and Records Administration