‘Engine room leak’ sealed fate of US Navy submarine

What you need to know: Commissioned in 1961, USS Thresher (SSN-593) was the most advanced nuclear-powered attack submarine of its time, designed to dive deeper and operate quieter than any predecessor.

-On April 10, 1963, during deep diving tests off Cape Cod, the Thresher sank with all 129 crew members and civilian technicians on board, marking the worst underwater disaster in the history of the US Navy.

-Although the exact cause remains unclear, a Navy investigation suggested that a leak in the engine room caused the reactor to shut down and fail to surface.

-The tragedy prompted the Navy to implement the SUBSAFE program, significantly improving submarine design, construction, and safety protocols, and avoiding similar losses in subsequent years.

USS Thresher – The worst American underwater disaster

When the U.S.S. Thresher was launched on July 9, 1960, some in the United States Navy considered it the most advanced submarine in the world. Capable of reaching speeds and depths never before achieved, the USS nuclear-powered attack submarine had much to like. Thresher (SSN-593).

In hindsight, this could be seen as a case of hubris.

Still, the submarine represented a major advancement in design. Developed to find and destroy Soviet submarines, USS Thresher was actually the fastest and quietest submarine of its time – and it was also equipped with the most advanced weapons system, which included launchers for the US Navy’s anti-submarine missile, then at the cutting edge of technology, the SUBROC. She was the lead boat of the new class of 3,700-ton nuclear-powered attack submarines.

Built at the Portsmouth Naval Shipyard in Maine and commissioned in 1961, SSN-593 began sea trials, including weapons tests in the Western Atlantic and Caribbean Sea. Once testing is complete, the ASU Thresher returned to its builders for an overhaul. No serious problems were detected and everything did not go as planned.

In early 1963, a minor disaster occurred when following maneuvers off Charleston, South Carolina – observed by the US Naval Antisubmarine Warfare Council – the boat was accidentally struck by a tugboat, resulting in serious damage. damage to ballast tanks. SSN-593 was forced to undergo repairs at the Electric Boat Company’s facility in Groton, Connecticut.

The accident was only a harbinger of an even worse disaster.

Lost at sea

Following repairs, USS Thresher started the trails – and on April 10, 1963, she took to the sea for a deep diving exercise. On board were 16 officers, 96 sailors and 17 civilian technicians. While conducting a depth test off the coast of Cape Cod, the submarine unexpectedly sank to the sea floor. The USS Lark (ASR-20), a PenguinA Class 1 submarine rescue vessel, which was also participating in the exercises, received a communication from the USS Thresher which indicated that the submarine was experiencing minor problems.

Tragically, that was the last time anyone heard of the doomed submarine.

The boat sank in the Atlantic Ocean with all hands off the coast of New England. It was the first nuclear submarine disaster and, to date, it constitutes the highest death toll with 129 deaths.

The exact cause of the accident is not known. Mechanical failures and even Soviet interference have been suggested as possible causes for the submarine’s sinking and loss. However, a U.S. Navy investigation determined that the most likely cause of the accident was a leak in the engine room, which may have been due to pipe corrosion.

When the ship’s engine room flooded, saltwater spray shut down the nuclear reactor. As a result, the U.S.S. Thresher’The main ballast tank did not explode after ice formed in its piping. The crew likely could not access the equipment needed to stop the flooding.

Adoption of the SUBSAFE program

Even after half a century, few details of the court of inquiry have been released. Efforts continued to question exactly what caused the submarine’s loss. Retired US Navy Captain James Bryant – who previously commanded the boat – even sued the Navy in 2019 to force the release of unclassified investigative documents detailing the submarine’s operation during its last diving. The maritime service had previously refused to grant Bryant’s request for documents under the Freedom of Information Act.

Although the exact cause of the accident has not yet been resolved, there were some good things about the accident. In addition to the improvements made to the Permit-class, the disaster also forced improvements in the design and quality control of all U.S. Navy submarines. The Navy has also established additional safety procedures, including the adoption of the SUBSAFE program. This required each submarine to pass a series of safety tests and since this effort ended, the Navy has suffered no further losses of the type that tragically ended the USS’s brief service career . Thresher.

Eventually, as it was lost at sea, the USS Thresher was not decommissioned by the US Navy and remains on “Eternal Patrol”.

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Experience and expertise of the author: Peter Suciu

Peter Suciu is a writer based in Michigan. He has contributed to more than four dozen magazines, newspapers and websites with more than 3,200 articles published during a twenty-year career in journalism. He writes regularly on military hardware, firearms history, cybersecurity, politics, and international affairs. Peter is also a Contributing writer for Forbes and Liquidation Jobs. You can follow him on Twitter: @PeterSuciu. You can send an email to the author: (email protected).

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