On the morning of April 10, 1963, at approximately 9:18 a.m., USS Thresher was lost with all 129 crew and civilian riders on board. Thresher had just completed a nine-month overhaul and modernization availability at Portsmouth Naval Shipyard in which she received new electronic and sonar equipment as well as other upgrades and repairs. She had departed from the shipyard just the day before. Wives and children waved to the crew members, as three tugs nuzzled against her and guided her away from her berth, anxious for them to return after completion of the planned two-day trial.
Conducting several successful shallow dives along the way, Thresher transited east-southeast to her dive point 220 miles off of Cape Cod where the Continental Shelf ends and the ocean’s depth plummets to 8400 feet. As her controlled dive began in 100-foot increments, Thresher sent routine messages to the rescue ship, USS Skylark. At 9:17 a.m., Skylark received a garbled message “…minor difficulties, have positive up-angle, attempting to blow.” Then Thresher went silent. Skylark attempted to regain contact by all means available, but to no avail. Thresher was lost.
Despite the Navy’s rigorous investigation, the exact cause of this tragedy is unknown; however, the following is the likely sequence of events:
•One or more silver-braze piping joints in sea water systems failed, resulting in engine room flooding.
•Due to the ship’s design and system arrangements, the crew was unable to access vital equipment to control the flooding.
•Saltwater spray on electrical components caused electrical panels to short circuit, the reactor plant to shut down and loss of propulsion power.
•The emergency main ballast tank blow system failed to operate properly. Restrictions in the piping system coupled with excessive moisture in the air led to ice formation and subsequently plugged of the airway.
The lives of the families that experienced this tragedy were forever changed. Wives were now widows; children fatherless. You may recall a WIB article I wrote back in October in which I discussed attending the dedication of the Thresher Memorial in Arlington National Cemetery and sitting amongst the surviving family members of the Thresher crew. The experience brought this event full circle in my mind and made me feel a personal, not just professional, tie to the Thresher disaster. The pain of this disaster is still with them–I saw it.
Multiple issues may have contributed to the loss of the 129 lives: perhaps poor workmanship, or testing, or a design or engineering error. Imagine what must have gone through the minds of the folks that worked on Thresher, wondering if it was their work that caused the loss.
This pivotal point in US Navy submarine history marks the event that sparked the inception of the Submarine Safety (SUBSAFE) program. Since the inception of the SUBSAFE program, no SUBSAFE certified submarine has ever been lost. In January of this year, the SUBSAFE, Fly-by-Wire Ship Control System and material condition certification of the PCU Vermont was revoked due to an undocumented condition on the ship. This loss of confidence in our certification process was unprecedented and a stark reminder of just how critical our jobs are to the safety of the ship, her crew, and their families.
We cannot lose sight of the fact that it is the robust material condition that we design into our ships, the expert craftsmanship, the technical rigor of engineering, the comprehensive testing and certified documentation combined with the Special Emphasis Program (SUBSAFE, DSS-SOC and Fly-by-Wire Ship Control System) requirements that provide the assurances that our submarines and their crews will be safe and on mission. We have the responsibility to maintain our vigil on the loss of the USS Thresher every day in all the work that we do, by applying the lessons learned and not losing sight of it despite the many distractions. It is especially tough this year with COVID-19 and all the challenges it brings to us. However, every job you complete, every document you sign, every decision you make, day-to-day, contributes to the material condition of our ships.
It is the sum of all your daily acts, as employees of the greatest submarine builder in the world, which ultimately allows the certification of our ships to go to sea. It allows their safe deployments and allows its sailors and their families to have the sacred trust and confidence that the ship will return safely, every time, no matter what.
Please stay safe and healthy.
Stephen Kirkup,
Director of Quality Assurance and Special Emphasis Programs
Safety Update: Installation of Speed Tables on Eastern Point Road
In an effort to increase safety at Electric Boat’s Groton shipyard, two speed tables are being installed across Eastern Point Road this week. The tables, a few inches tall and marked with yellow stripes, are designed to slow vehicle traffic in an area frequented by pedestrians. The first speed table crosses Eastern Point Road just...Continue reading→
EB firefighters recognized for life-saving rescues
Five members of the Electric Boat Fire Department in Groton were recognized for perilous, life-saving rescues during a pair of multi-alarm fires that engulfed apartments in Groton and New London in 2025. Firefighters Thomas Gugliotti, Arthur Keaten, Theodore Bartkoski, James Brady and Capt. Ryan Boulanger were each presented with Lifesaving Awards and the prestigious 2026...Continue reading→
The Barnacle: Parking Enforcement That Sticks
Meet the Barnacle, Electric Boat’s newest parking-enforcement tool that will begin deployment in the Groton shipyard starting Monday, June 15. As our enterprise continues to grow, we are dedicated to ensuring parking is safe, fair and accessible to all. The Barnacle is an immobilizing parking-enforcement device that attaches directly to a vehicle’s windshield using heavy-duty,...Continue reading→
Honoring the U.S. Army Birthday
June 14th marks the 251st Birthday of the United States Army, a moment to honor the enduring legacy, bravery, and sacrifice of those who have worn the Army uniform since 1775. As the oldest branch of the U.S. military, the Army has played a vital role in shaping our nation’s history and safeguarding its freedoms....Continue reading→
Rayha Report Ep. 20: 2026 EB Signing Days
Electric Boat held recent Signing Day ceremonies at Cranston West High School on May 21 and the Garde Arts Center in New London on May 28. EB President Mark Rayha spoke with students about their decision to join EB and educators who prepare their students for careers in shipbuilding. Click here to see the latest installment of the Rayha...Continue reading→
Save the Date: CT Health Fairs Kick Off June 9
A Message From Dan Vieira and Kathleen Heller At EB, Safety and Wellness go far beyond meeting basic compliance standards. Our focus is on building a culture where employees can thrive in every aspect of their lives. Prioritizing wellbeing is vital to being our best on the job and at home with our families. ​​...Continue reading→
Supporting Our Neighbors Impacted by The Ledges Apartments Fire
Early Sunday morning, a devastating fire occurred at The Ledges Apartments in Groton. Eighteen fire departments, including Electric Boat’s, responded.  Thanks to the heroism of these first responders no residents were injured. The fire did, however, displace more than approximately 50 residents and destroyed or damaged 44 units in the building. Several EB employees were...Continue reading→
Pride Month Celebrations at Electric Boat
June 1st marks the start of Pride Month, a time for millions of LGBTQ+ individuals and allies around the world to come together in celebration and reflection. From film festivals and art shows, to marches and concerts, Pride is a vibrant tribute to LGBTQ+ culture, history and the relentless spirit of activism. It’s a chance...Continue reading→
Celebrating Our Next Generation of Shipbuilders
The Next Generation of Shipbuilders Takes the Stage Over the past two weeks, Electric Boat welcomed the next generation of shipbuilders at our Rhode Island and Connecticut Signing Day celebrations, marking the beginning of a journey that will help shape the future of our company and our nation’s defense. Held at Cranston High School West...Continue reading→
Update: Gold Star Bridge Project – Upcoming Traffic Impacts
CT DOT is preparing to enter the next major phase of the Gold Star Memorial Bridge Rehabilitation Project, and employees should expect new traffic patterns that may affect travel to and from EB’s Groton and New London facilities. A crossover will direct two northbound lanes onto the southbound bridge, as shown in this CT DOT...Continue reading→
