Keeping Memory Alive – USS Thresher (SSN 593) Lost at Sea: April 10, 1963

You are currently viewing Keeping Memory Alive – USS Thresher (SSN 593) Lost at Sea: April 10, 1963

Fellow Shipbuilders,

Today we commemorate the 60th anniversary of the loss of the USS Thresher after an extended post shakedown availability at Portsmouth Naval Shipyard. On this day in 1963, 129 men lost their lives; 129 families lost a son, a father, a brother. As a result of that tragedy, three generations of descendants wonder what could have been, and how many siblings, children and grandchildren never were. We also wonder what those men would have continued to contribute to this nation, if they had the chance.

On Tuesday, April 9, 1963, USS Thresher was gently pushed her from her berth at Portsmouth Naval Shipyard. On shore, children of the crew sitting on their mom’s laps honked and waved from parked cars as they watched her departure, having just said their goodbyes and looking forward to seeing their dads in two days, just in time for Easter egg hunts and a family feast.

On board Thresher, as she progressed to the dive point overnight and into the next morning, a series of shallow dives were conducted to ready the crew for the dive to test depth. 220 miles off shore on the morning of the 10th, Thresher had reached the continental shelf and was ready to dive in 8,400 feet of ocean. As her escort ship USS Skylark stood by, LT CDR John Wesley Harvey ordered the ship to submerge and the bow slipped beneath the surface of the ocean. All was well as Thresher gradually dove in 100-foot increments. Routine messages were relayed between Skylark and Thresher as she proceeded to the depths. Then, unexpectedly, a message from Thresher—“Experiencing minor difficulties, have positive up angle, am attempting to blow”—was received, followed by additional garbled transmissions. At approximately 9:18 a.m., Thresher was lost.

We will never know for sure what occurred that day, but it is suspected that one or more brazed seawater pipe joints failed; access to vital equipment was blocked hindering ability to isolate the flooding; salt spray on electric panels caused them to short out; loss of those electrical panels caused the plant to shut down, and without the plant, loss of propulsion; emergency measures were taken, but moisture in the emergency main ballast tank blow system likely caused airways to restrict and freeze over and become blocked, hence preventing lifesaving air to fill the ballast tanks and the ship from returning to the surface with its only remaining recovery system.

Out of this tragedy came volumes of lessons learned, changes in perspective, new design and operating requirements and a culture of excellence that still exists today. Out of this tragedy, the SUBSAFE program was born—the first of three Special Emphasis Programs (SEPs) whose sole purpose is to protect the platform and its crews from avoidable risks on an already dangerous mission. As a result, no SUBSAFE-certified submarine has ever been lost. As our previous Electric Boat president, John Casey, many times said, “We send our one and only product, a U.S. Navy nuclear submarine, “into an environment that otherwise would not sustain human life and expect it to return every time.” The Special Emphasis Programs (SUBSAFE, DSS-SOC and Fly-by-Wire) have assured just that.

One of our EB-built boats, the USS Hartford in our yard right now, is an example of that success. As many of you know, Hartford survived a terrible collision in the Straits of Hormuz in 2009, and brought each of her sailors home to their families—and it’s because of our adherence to design requirements, rigorous engineering standards, proper training, mentoring and supervision, the drive for first-time quality, detailed inspections, testing and certification documentation—that we can continue to ensure the excellent performance of our products. Each time Electric Boat sends a ship to sea, whether it be a newly constructed ship or a ship we have in for maintenance, I proudly provide the Electric Boat SEP certification, with extreme confidence that the ship is safe to go to sea “into an environment that otherwise would not sustain human life,” and I do that on behalf of the work accomplished by the men and women of Electric Boat. That extreme confidence cannot, can never, be allowed to evolve into a culture of arrogance based on previous success. Our duty and responsibility to those 129 lost souls on USS Thresher is to never allow that to happen again.

The SUBSAFE culture of excellence cannot be allowed to become fragile. We live in a day-to-day world where facts are ignored or revised, consequences aren’t clear, threats aren’t recognized, reality is corrupted by social media, and if it’s not streaming on your phone, it’s not important. I’ll tell you this—that cannot be the culture inside our gates. The fact is, there are existential threats out there, and consequences to our nation if we can’t deliver our ships so that they can perform their mission to protect us. We owe it to our sailors to build our ships, with velocity (that’s speed with solid foundational direction) to rigorous standards with first-time quality, so they remain safe and can continue to trust their ship will perform as designed, allowing them to focus on their mission.

Commemoration of this event is a remembrance of who those 129 souls were—a remembrance of the impact that day had on their families and the U.S. Navy—and a remembrance of the first nuclear submarine lost. Sixty years ago is beyond the memories of most Americans, in fact, those that actually remember that day are very rare. Many of us have seen tragedy and know how tragedy impacts us personally and directly, but time takes its toll. Some remember the loss of the Space Shuttle Challenger and the horror on the faces of the families and students there to celebrate the milestone launch of the first teacher into space; more remember the loss of Space Shuttle Columbia and the streaking of debris across the sky; and even more so 9/11, 22 years ago already. Many of the folks coming in our gates today were not yet born when that happened. As the years progress on, the pain becomes distant, the memories fade, the first-hand witnesses are gone, new generations mature, and we become vulnerable to tragedy again, maybe because of ignorance, maybe its arrogance or maybe its complacency.

Our challenge here is to turn up the gain on the consequences of not getting it right, because there are consequences if we don’t maintain our diligence. We must fight the three enemies of our Special Emphasis Programs—ignorance, arrogance and complacency—so that they find no path into our submarines. These enemies are always poised to attack and are always looking to find a way in, just like the pressure of the sea is always trying to find a way in. I ask you all to join me in this fight, to maintain our rigorous standards, to teach those that need to learn and to never assume that it doesn’t matter if a step was missed or that a requirement was not met. Don’t let the enemies in our gates. We owe it to those 129 men that we’ll maintain the watch on ship safety and first-time quality and will keep today’s sailors safe so that they can in turn protect us and our great nation.

I’ll close with words from Vice Admiral Grenfell, then Commander Submarine Force, United States Atlantic Fleet. “They are remembered not as men who were, but as men who are; who because of their profession of the undersea, have given us greater knowledge of its mysteries and opened broader paths for its exploration and use.”

Please go forth and achieve excellence in the work you do today and every day.

Thank you.

Stephen C. Kirkup
Director, Quality Assurance and Special Emphasis Programs

Pathways to the Deep Officially Opens at Mystic Aquarium

On Monday, May 11th, we officially cut the ribbon on Pathways to the Deep, a brand-new interactive exhibit at Mystic Aquarium that connects ocean science, technology, exploration and careers through hands-on learning and discovery. This collaborative effort between General Dynamics Electric Boat, Mystic Aquarium, the Submarine Industrial Base and Build Submarines was created to spark curiosity and...Continue reading→

Electric Boat featured in ADC’s ‘Homefront’ Video Series

General Dynamics Electric Boat is featured in the latest episode of the Association of Defense Communities’ (ADC) Homefront video series, which examines military communities across the country.  The episode highlights Electric Boat’s long-standing partnership with the U.S. Navy, the generations of shipbuilders who power our mission and the opportunities ahead for the next wave of...Continue reading→

Rayha Report Ep. 19: Operations Leadership Hiring Initiative

In his latest Rayha Report, EB President Mark Rayha speaks with Chief of Talent Acquisition Meredith Kyle on the ways the company is boosting operations leadership hiring. Joining them is Konrad Wennberg and Mike Simmons, who provide insight on their internal moves from engineering to operations supervisor positions.​

Lauren Knapp Honored with Victoria Soto Memorial Award

We are proud to celebrate Lauren Knapp for being named a recipient of the prestigious Victoria Soto Memorial Award, presented by Big Brothers Big Sisters of Connecticut. This recognition highlights Lauren’s exceptional commitment to mentorship, community engagement and making a meaningful difference in the lives of young people. The Victoria Soto Memorial Award honors individuals...Continue reading→

Groundbreaking Ceremony Held for New Warehouse in North Stonington

Electric Boat broke ground Wednesda​​y on a new warehouse that will support shipbuilding operations in Groton and Quonset Point. The 480,000‑square‑foot facility, located at 45 Frontage Road in North Stonington, will streamline how material moves across different work sites. Electric Boat purchased​​ the 55‑acre property from the Mashantucket Pequot Tribal Nation in 2025. The project...Continue reading→

Lessons From the Loss of USS Thresher (SSN 593) on April 10, 1963

​Photo by EB Employee Patrick “Pat” M. McCarthy, Principal Program Representative, Quality (D421). Electric Boat Shipbuilders, On the morning of April 10,1963, USS Thresher began her deep dive in 8,400 feet of water 220 miles off Cape Cod. During the dive, an unexpected message was received by USS Skylark, her escort ship: “Experiencing minor difficulties,...Continue reading→

Rayha Report Ep. 18: CT and RI Legislative Briefings

EB President Mark Rayha delivered Legislative Briefings to congressional delegations and local leaders in Connecticut and Rhode Island on Monday, March 23. See the latest installment of the Rayha Report for a recap of the events. ​​