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Featured Article: Unraveling the Thresher Story (Revised)

“Correction: An earlier version of this article was published prematurely before the article was properly reviewed and edited.”

On 10 April 2022, 59 years will have passed since the loss of the USS Thresher with 129 lives lost forever. This loss represents one of the greatest losses. All of us suffered, the Navy, the families, and the country. This was an unbelievable catastrophe in peace time. On that very day, I was the Shipyard Watch Officer at Portsmouth Naval Shipyard. This was an incredible experience.

Thresher was the most advanced nuclear submarine in the entire world. None of the people that rode the submarine for the sea trial considered the trials unsafe. Thresher had been through all the tests and trials of a new submarine. The submarine had operated with the operating forces for a year and been through shock trials and test depth over 40 times without any problems.

You might ask, what happened to cause this major loss of a submarine and 129 precious human beings.  It is my intention to give honor to those men, but also to reveal some of the recent thinking that will show how the system, the entire Navy, and the people involved missed some very important issues that could have prevented this great loss.

All these passing years, there have been many people who have questioned the Navy’s position and published reasons for the loss of Thresher on the sea trial. The Navy kept most of their information classified, and for years would not release that information.  Several books have been written on the loss of Thresher.  Most have not focused on the reasons for the loss.

Some knowledgeable submarine people tried the Freedom of Information route.  No effort resulted in providing the information. A retired nuclear submarine officer filed a lawsuit that succeeded in releasing information to the public.  After my article was published in the Naval Institute Journal, this retired Naval Officer and I got to know each other. He formed a team of experienced submarine people to analyze the information released. This group published an article in the Naval Institute Journal. He gave me permission to use some of the article his team published in 2021.      

Here are some extracts from that article:

The apparent cause of this disaster was not appreciating the inherent dangers of nearly doubling the THRESHER Class’s test depth (TD) (maximum operating depth) over that of previous submarine designs.  Respected open literature states Threshers TD was 1,300 feet, nearly twice the 700-foot test depths of USN’s other post-World War II submarines.  For this deeper-diving, high-performance submarine, the design, fabrication, repair, quality assurance, and operational procedures were not improved fast enough or applied with enough rigor to prevent the disaster.

There were many contributing factors.

No Backup to Nuclear Propulsion

Contract Design Specifications limited Thresher’s recovery from negative buoyancy at TD, such as flooding to using its nuclear propulsion to drive the submarine to the surface.  Common events preventing a recovery were either an automatic reactor emergency shutdown (scram) or failure of the stern plane control surfaces in a dive position (jam dive).  Thresher’s scram procedure secured steam to the engine room, stopping the main engines and steam-driven Ships Service Turbine Generators (SSTG)

About the Author

JOSEPH F. YURSO, Captain USN (retired), is currently Director of Technical Development for Q.E.D. Systems Incorporated of Virginia Beach, Virginia. He has been with Q.E.D. for over 30 years.  Mr. Yurso has been a member of the American Society of Quality since 1989 and was a founding member and past chairman of the Tidewater section. Other positions Mr. Yurso has held include National President of the American Society of Naval Engineers. He is a past President of the American Maritime Modernization Association (AMMA).  Mr. Yurso began his career as a commissioned officer serving 30 years in the United States Navy. 


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