Transcription
The most advanced nuclear submarine in the world sank during a routine test dive in 1963. 129 men, no survivors. From the first distress call to silence, less than 60 seconds. The last message anyone ever received was four words, "Minor difficulties attempting to blow." Then nothing.
The Navy investigated for months and produced 1,700 pages of testimony and evidence, then classified almost all of it. 19 pages made it to the public. 19 out of 1,700. It took a federal court order 60 years later to get the rest released. And when it finally was released, parts of it were still blacked out. The USS Thresher is still down there. The documents are still redacted. And the families of those 129 men have still never had a complete answer. That is what I want to find out.
Most people who know the USS Thresher know it sank during a test dive. What I want to know is what was in those 1,700 pages that the Navy decided the public could not see for half a century. And whether the families of those 129 men ever got the truth. Because the more I looked into this one, the more I found myself going back and checking the same details over and over again. Some of them I still find genuinely hard to accept. But before we get to the classified documents, we need to understand what kind of submarine the USS Thresher actually was.
This was not just any vessel. The USS Thresher was the most advanced nuclear attack submarine in the world. When it was commissioned in August 1961, it was faster and quieter than anything the Soviets had. Built at Portsmouth Naval Shipyard in Kittery, Maine, it used a revolutionary teardrop hull design and high-strength steel that could withstand depths no previous submarine had reached. The USS Thresher was designed to find and destroy Soviet submarines before they could threaten American cities. It was the lead boat of its entire class. It was the benchmark that every future American submarine would be built against.
It was also, in April 1963, fresh out of a 9-month overhaul and crewed largely by men who had never sailed on the USS Thresher before. Many were inexperienced with this particular boat. Here is something that did not make it into the initial public reporting. When the USS Thresher entered Portsmouth Naval Shipyard in July 1962, the overhaul was supposed to last 6 months. It was extended to nine. During that extension, the majority of the experienced crew was reassigned. Of the 11 officers aboard on April 10th, only three had spent any significant time on the USS Thresher. Most of the enlisted men were similarly unfamiliar with the submarine. The Navy was under pressure to get fast attack submarines operational as quickly as possible. The Cold War did not stop for crew training.
Stay with me here because the sequence of events on the morning of April 10th, 1963, takes less than 60 seconds to describe. Once you hear exactly what happened and exactly what did not happen, the question of why the report was classified starts to answer itself.
On the morning of April 9th, 1963, the USS Thresher departed Portsmouth Naval Shipyard in Kittery, Maine. The children of the crew sat in their mothers' cars on the pier. They honked their horns and waved as the submarine pulled away. The mothers waved back. Nobody knew it was the last time they would ever see their fathers.
The USS Thresher and its escort ship, USS Skylark, arrived at a test dive area 220 mi east of Cape Cod in 8,400 ft of water. The USS Thresher began its controlled descent in 100-ft increments. Routine messages were relayed to Skylark every 15 minutes as the submarine went deeper. At 9:12 in the morning, Skylark received a routine check-in. The USS Thresher reported it was proceeding to test depth, 1,300 ft. It was the deepest dive the submarine had ever attempted since its overhaul. At 9:17, Skylark received a garbled transmission. The words, partially reconstructed afterward, were, "Experiencing minor difficulties. Have positive up angle. Attempting to blow." That meant the USS Thresher was trying to force air into its ballast tanks to drive itself back to the surface. There was one more transmission, a single number, 900, and then nothing.
Skylark spent the next hour dropping signal grenades into the water, the standard signal for a submarine to surface. There was no response. By mid-afternoon, 50 Navy ships were converging on the area. At 6:30 in the evening, families were notified. The next morning, the Navy announced the USS Thresher was lost with all hands, 129 men on a routine test dive.
Now, here is where this story gets genuinely troubling because the Navy knew, or should have known, exactly what had gone wrong. And the question of whether it was honest about that is what has driven this case for 60 years. The court of inquiry convened within days. Over 8 weeks, it heard testimony from 120 witnesses. It gathered 1,700 pages of documents, charts, drawings, photographs, and technical reports. Then it reached its conclusion. A saltwater piping joint in the engine room had failed. The joint was silver braised rather than welded, a known shortcut in submarine construction at the time. The joint failed. Water flooded the engine room. The water shorted out the electrical systems. The reactor shut down. The USS Thresher lost all propulsion. The crew attempted an emergency blow, forcing air into the ballast tanks to drive the USS Thresher back to the surface. The high-pressure air pipes froze solid. Moisture in the system had turned to ice at depth. The air could not get through. The USS Thresher could not stop its descent. It passed through crush depth and imploded.
Here's the part I went back and checked. The Navy released just 19 of those 1,700 pages to the public. 19. The rest were classified. For over 50 years, the families of the 129 men who died received no access to the full account of how their husbands and fathers died. In 2019, a retired Navy captain named James Bryant, a man who had commanded three submarines the same class as the USS Thresher, sued the United States Navy to force the release of the full report. A federal judge agreed with him. The Navy was ordered to begin releasing the classified pages, one batch at a time. All 1,700 pages of testimony have now been released, but with redactions. Sections remain blacked out. The families still do not have the complete picture.
Here is the part nobody talks about. Those released documents did not clear the Navy's name. They complicated it. The documents revealed that the Navy knew about the silver brazed joint problem before the USS Thresher sank. Inspections had flagged substandard welds in the piping systems. The work was not corrected before the submarine went back to sea. The documents also revealed that the overhaul had been rushed, not because of any technical necessity, but because of schedule pressure. Fast attack submarines were needed operationally. The USS Thresher was pushed back to sea before the work was fully verified.
And then there is this. The Navy's official position is that the USS Thresher imploded at 9:18 in the morning on April 10th. Gone instantly. No possibility of survivors. But the newly declassified documents include the account of USS Seawolf, one of the search submarines sent to the area. The Seawolf's commander reported 24 hours after the USS Thresher was declared lost, the Seawolf was still actively searching for signs of life. Still listening. Still looking. The official implosion timeline and the search submarine's own account do not fully match. Nobody has explained that discrepancy.
One analyst, Bruce Rule, the United States Office of Naval Intelligence's lead acoustic analyst for over 40 years, reviewed the SOSUS hydrophone data from April 10th, 1963, and reached a different conclusion entirely. Rule concluded the primary cause was not flooding at all, but an electrical bus failure that shut down the main coolant pumps and triggered a reactor shutdown. According to Rule, the SOSUS data shows the electrical failure occurred at 9:11, 6 minutes before that final garbled message. If Rule is correct, the flooding theory the Navy has maintained for 60 years is wrong. And the Navy has had access to that acoustic data since 1963.
The USS Thresher is still down there, 220 miles east of Cape Cod, 8,400 feet below the surface of the North Atlantic. The wreck lies in five major pieces scattered across an area of 33 acres of ocean floor. The reactor is still there. The nuclear fuel is still there. The Navy monitors the site periodically for radiation. It has not released the results of those surveys publicly. The location of the wreck is technically known, but not publicly promoted. The site is designated a war grave. No recovery operation has ever been seriously proposed. The wreck is in too many pieces, at too great a depth, with active nuclear material on board.
The 1,700 pages of the court of inquiry were eventually released, but with sections still blacked out. The SOSUS acoustic data from April 10th, 1963, has never been fully declassified. 129 men went to sea on the morning of April 9th, 1963. Their children waved from their mothers' cars on the pier in Kittery, Maine. They were looking forward to seeing their fathers in 2 days, in time for Easter. They never came home. The USS Thresher is not still classified because the Navy has no answers. It is still classified because some of the answers were ones the Navy did not want to give.