Watershed Event


By Brenda Ellis

On April 10, 1963, the nuclear submarine USS Thresher departed Portsmouth Naval Shipyard in Kittery, Maine, headed for a rendezvous with the submarine rescue ship USS Skylark, which would accompany it during deep-dive tests.

Designed to hunt and destroy enemy Soviet vessels, the Thresher was the ultimate attack submarine for its time. It could dive deeper than any other submarine. It had a high-speed hull, the most powerful sonar in existence, special silencing features and advanced weapons.

The submarine, which had just completed a routine overhaul, was crowded that morning, as is usual for sea trials. Besides the normal crew of 108 officers and men, 21 extra personnel were shoe-horned in.

At about 9 in the morning, Thresher signaled “Proceeding to test depth.”

At about 9:13 a.m., Thresher signaled that she was experiencing “minor difficulties,” that the boat had taken a positive angle (the bow was higher than the stern), and that the crew was attempting to blow main ballast tanks.

From that point only garbled fragments were received, with the words “test depth” the only discernible phrase. At 9:18, Skylark personnel heard sounds they identified as those of a submarine breaking up.

[quoteit]The Thresher was lost that day with all 129 hands. It was history’s first loss of a nuclear submarine and remains the worst accident in U.S. submarine history.[/quoteit]

Further attempts at communication failed. The Thresher was lost that day with all 129 hands. It was history’s first loss of a nuclear submarine and remains the worst accident in U.S. submarine history.

Two men who never met nonetheless link the Thresher to Vanderbilt: Pat Garner and Steve Krahn. One lost. One a nuclear engineer determined to keep the memory of the Thresher alive.

Lt. Cmdr. Pat Mehaffy Garner was second in command on the Thresher. The submarine’s executive officer, Garner was just 31 and serving on his third submarine. The Memphis, Tenn., native earned a bachelor’s degree in psychology from Vanderbilt in 1953 and had been commissioned an ensign through Vanderbilt’s Naval ROTC program. He had been promoted to the rank of lieutenant commander a full year ahead of his contemporaries. When he perished aboard Thresher 50 years ago, he left behind a widow, Alice Stets Garner, and two daughters.

The loss of Thresher was a watershed event for the U.S. submarine force, and it led to significant advances in submarine safety in design, construction and maintenance, says Steve Krahn, now a Vanderbilt professor of the practice of nuclear environmental engineering who has studied the Thresher for decades.

Krahn, who was just a small boy when Thresher was lost, came to Vanderbilt in 2010 to help create a program in nuclear environmental engineering studies. “I welcome any opportunity to talk about the Thresher,” Krahn says. “I’m passionate about it.”

He was associated with the Naval Nuclear Propulsion program throughout a 10-year Navy career as a nuclear engineer in the Naval Reactors organization and later was stationed at the Portsmouth Naval Shipyard years after the Thresher tragedy. “Every year on April 10, the Portsmouth Chapel bell rings 129 times,” he recalls.

Krahn spent four years leading repair and maintenance on Thresher-class subs: First as nuclear ship superintendent (Navy-speak for project manager) on the USS Greenling in 1984 and 1985, then as senior ship superintendent (senior project manager in charge of an entire $140 million overhaul) on the USS Gato from 1985 to 1987.

Thirty years after the Thresher tragedy, Krahn delivered the keynote address at the 1993 U.S. Department of Energy’s Standards Conference: “The Loss of USS Thresher (SSN593): Lessons for the Development, Implementation and Use of Standards.” At the time of that conference, he was a senior executive staff member of the Defense Nuclear Facilities Safety Board.

“[The Thresher tragedy] has formed portions of articles I have written for peer-reviewed journals on the Naval Nuclear Propulsion program,” he says, “and I have been requested by NASA and the Sloan School at MIT, among others, to discuss the loss of Thresher and its implications for the management of technology.”

After the loss of the Thresher, a five-member Navy court heard 120 witnesses and collected 255 exhibits over eight weeks, most of it behind closed doors. Ultimately, the evidence filled 1,718 pages bound into 12 secret volumes. In Congress the Joint Committee on Atomic Energy also conducted an investigation, some of it in secret, and issued a nearly 200-page report. The Navy has declassified some information, but some of it remains secret, says Krahn, who has reviewed the Navy and congressional investigations in their entirety.

A Court of Inquiry concluded that the failure of a salt-water piping-system joint likely led to the submarine’s demise.

Thresher was the lead, or first, boat of a new class of nuclear submarines designed to go significantly deeper than previous classes,” Krahn explains. “In July 1962, after nearly a year of record-breaking operations, Thresher returned to Portsmouth for an overhaul.” The April 10, 1963,voyage was the Thresher’s first since completion of the overhaul.

As a direct legacy of the Thresher tragedy, Krahn says, the Navy shortly thereafter implemented SUBSAFE, a nuclear submarine quality assurance and certification program designed to maintain the safety of the fleet. Since the program began in 1963, only one submarine, the non-SUBSAFE-certified USS Scorpion, has been lost. The Navy secretly hired Cmdr. Robert Ballard to find, map and collect visual data of the Thresher and Scorpion wreckage in 1985. When that task was completed, Ballard used the same debris-field search techniques to find the remains of the RMS Titanic later the same year.

After leaving the Navy, Krahn worked at Perot Systems, which was awarded a multimillion-dollar comprehensive submarine support contract in 2002 by the Naval Sea Systems Command. He left Perot Systems in 2007 and worked in nuclear jobs at the Department of Energy, culminating in his appointment as deputy assistant secretary for safety and security in the Office of Environmental Management.

Now he shares lessons gleaned through his career with his Vanderbilt students.

“We started with Introduction to Nuclear Environmental Engineering, and we now have four graduate-level classes and six Ph.D. candidates,” he says. Last year he presented a special topics lecture to civil engineering seniors, “Pushing the Boundary of Technology: Lessons from the Loss of the USS Thresher.”

And Vanderbilt’s NROTC, founded in 1945, continues to help prepare students for naval careers. More than 2,200 men and women have completed the NROTC program at Vanderbilt and have gone on to serve as officers in the U.S. Navy and Marine Corps. The NROTC unit at Vanderbilt is also host to Tennessee State University and Belmont University NROTC students. Nowadays the unit comprises about 50 midshipmen, approximately 25 percent of whom are female.

One other Vanderbilt connection deserves mention. Before his assignment to the Thresher, Pat Garner was chief engineer aboard the nuclear submarine USS Skate, taking part in all three of its Arctic expeditions below the ice. Garner was aboard the Skate in 1959 when it became the first submarine to surface at the North Pole.

Skate was also the first to rendezvous with another submarine during a secret mission under the North Pole. The other sub was the Seadragon, whose skipper was Dan Summitt, a Vanderbilt School of Engineering student in the 1940s. The two nuclear-powered submarines met under the polar ice cap and surfaced together through a hole in the ice.

Summitt, who died in 2009, served as an aid to Adm. Hyman Rickover, father of the nuclear Navy, retiring in 1974. Steve Krahn spent two of his years at Naval Reactors as chief design engineer for the nuclear propulsion plants aboard the Skate and Seadragon.

Readers wishing to learn more about the U.S. Navy’s role during the Cold War era may be interested in reading Summitt’s memoir, Tales of a Cold War Submariner, published by Texas A&M University Press in 2004.


Brenda Ellis is senior information officer for the Vanderbilt School of Engineering.

Watch a 1963 Navy newsreel video about the Thresher disaster.

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