The Death of the USS Thresher: The Story Behind History… (2023)


931 reviews28.5k followers

June 23, 2023

“In late 1961, Admiral Anderson [testified] that the Soviets have ‘a limited number of nuclear-powered submarines.’ He added that the Soviets were probably having ‘some problems’ with them and ‘it wouldn’t surprise me if they lost some. We haven’t lost any yet and don’t intend to…’ The Soviet Navy had completed its first nuclear submarine, the K-3, in 1958, less than four years after the USS Nautilus. No Soviet nuclear submarine had been lost to that time. But now the United States had lost a nuclear submarine – and it had lost the best…”
-Norman Polmar, The Death of the USS Thresher: The Story Behind History’s Deadliest Submarine Disaster

The first time I heard about the USS Thresher – which sank during a test dive in 1963 – it was due to another, far more famous shipwreck.

In 1985, Dr. Robert Ballard discovered the remains of the RMS Titanic on the bottom of the North Atlantic. Unknown at the time, and only revealed later, the search of the ill-fated passenger liner had been a cover for Ballard’s true mission, which had been financed by the U.S. Navy: to find the Thresher, a nuclear-powered fast-attack sub lost with all hands.

The two disasters actually share some superficial similarities. Both the Titanic and the Thresher were cutting edge technologies at the time. Both died very early in their careers, Titanic on her maiden voyage, the Thresher on a test dive. Both rest very, very far from sunlight and air and the breath of life.

That is where the similarities end, however. The Titanic had 705 survivors able to bear witness. It is the most covered shipwreck in history, with a cottage industry of books, documentaries, and films. People have been arguing about Titanic for over a century, yet the broad outlines of her story have never been in doubt.

The fate of the Thresher is very different. She sank on April 10, 1963, while on a dive to her test depth off the New England coast. We know that once she slipped below the surface, she never came back. We know that all 129 men aboard her died. That is all the certainty we have.

This mystery clearly haunted Norman Polmar for a good portion of his life, and The Death of the Thresher is his attempt to put that obsession into words.


The Death of the USS Thresher is a slim book, coming in at 177 paperback pages of text. Originally published in 1964, it has been revised twice since, in 2001 and 2004. There are good reasons for the revisions, as this first arrived at the height of the Cold War, when just about every aspect of the tragedy was classified. This updated edition makes use of certain new information, including the sounds of the Thresher’s implosion, which were caught by then-top-secret sound surveillance system (SOSUS) listening posts. Other material covers the subsequent sinking of the USS Scorpion in 1968, and the loss of the Russian submarine Kursk in 2000.

For all that, the substance is still very thin. At the end of the day, there’s just not a lot to go on, and for as brief as the book is, it still feels too long.


I want to make clear that Polmar is considered an expert in this arena. He’s worked for the U.S. Navy for years, and has an insider’s knowledge. But – and you knew there’d be a “but” – this is an average book at best, and that might be generous.

It’s not simply that Polmar is a poor writer, because his skills are serviceable enough. It’s that this book is as uneven as a Minnesota road after a hard winter. Giving everyone involved the benefit of the doubt, this might be a function of the multiple editions, with the original flow having been disrupted by additions and subtractions. Whatever the reason, this is a bumpy read.


In terms of structure, Polmar very briefly covers the construction and fitting out of the Thresher, and follows her on her final cruise. The narrative is tightly focused on technical aspects and – with the minor exception of a few biographical incidentals about the commander – does not make any attempt to bring the crewmembers to life. Frankly, I respect Polmar’s decision. He knows his strengths, and his book’s purpose, which is to tease out the mysteries of Thresher’s last dive.


Unsurprisingly, Polmar is at his best during the sinking. Most of what we know about Thresher comes from her radio communications with a Naval support ship on the surface. As the Thresher went deeper, she made radio checks approximately every fifteen minutes. The dive to Thresher’s test depth (1,300 feet) began around 7:47 a.m. At 9:13 a.m., a garbled message from the sub was received, saying something to the effect that the sub was “experiencing minor difficulty,” had a “positive up-angle,” and was “attempting to blow.”

Polmar does a textual dissection of these words, founded on his own experience. He discusses what is – and what is not – a “minor difficulty” for a submarine at depth. He explains what it means to have a “positive up-angle,” and that when a sub is “attempting to blow,” it is releasing ballast to regain positive buoyancy and head to the surface.

At 9:17 a.m., a sailor thought he heard the words “test depth” from the sub, implying that the Thresher had exceeded her limits. Polmar notes that this is a safety factor, and passing it did not mean instant structural failure. Nevertheless, a minute or two later, there came a sound World War II vets recognized as a submarine breaking apart.

As Polmar concedes, this is an unusually difficult riddle to decode. He spends a lot of time on Thresher’s last words, but these messages were never recorded, while those who were listening can’t agree on what was said. Thus, all assumptions are based on a high-stakes game of telephone.


When a book is revised twice by a small press to include new information, there is bound to be some sloppiness. There are the expected grammatical errors, the changing of tenses, the repetition of information at different parts of the book. Some sections feel tagged on. Other sections feel hopelessly outdated and should have been excised. The biggest issue is in the presentation of Polmar’s theory. To wit: he never really delivers one in a coherent manner.

In his chapter on the most probable cause, he spends a lot of time discussing the potential problems with the brazed pipe-joints in the engine room. The Court of Inquiry thought that flooding might have caused a loss of power. With no propulsion, and with the boat out of trim, she began to sink. The crew tried to blow ballast, but the system did not work properly so deep.

Polmar seems to endorse this view in the text. But then, abruptly, in the last paragraph of the explanatory chapter, he suddenly says that it’s most likely that a nuclear reactor shutdown – known as a “scram” – precipitated the disaster. Before this moment, Polmar hadn’t even introduced this concept. In a later chapter, presumably added in a revision, he circles back to the topic to explain the scram theory. This is a rather frustrating way to convey information.


Polmar’s book got me really interested in the Thresher, but did not satisfy the curiosity it created. I took it upon myself to remedy this state of affairs. Recently, my wife and kids went out of town for the weekend. I cracked open a bottle of wine, turned on the computer, and settled in for a near-perfect night of watching YouTube documentaries. Right away, I stumbled upon the Holy Grail: Norman Polmar delivering an April 10, 2013 lecture at the Mariner’s Museum and Park in Newport News, Virginia.

Polmar is an incredibly engaging speaker whose presentation is roughly as disorganized as his book. It seems that the passage of time, Ballard’s visits to the sub, and Ballard’s ability to now talk about his visits, have given us even more information on the Thresher.

Polmar’s lecture clarifies that he doesn’t believe flooding occurred in the sub, since flooding hundreds of feet below the surface is never a “minor problem.” Instead, he theorizes that the Thresher encountered a non-vital electrical failure that turned off the coolant pumps and caused a reactor scram. The sub lost power and propulsion and began to head down. Blowing ballast didn't work due to moisture freezing in the strainers of high-pressure air valves of the blow system. The crew could not get power restarted in time. The boat’s integrity failed in an implosion so quick that the men couldn’t perceive it before they died.

I’ve seen it said that such an implosion might take a millisecond to occur, while rational human reaction takes 125 milliseconds.


Immediately after watching this lecture, I found a documentary featuring Dr. Ballard. I had a second, moderately-poured glass of wine – or opened a second bottle, I can’t recall – and watched that too. Ballard believes that flooding caused by the failure of the brazed (as opposed to welded) pipe-joints scrambled the electricity and led to a power outage. Despite more wine and internet searching, I couldn’t find a video of Polmar and Ballard facing off in a college-style debate. This contest of intellects will have to occur in my dreams alone.

Ultimately, for all the respect I have for Polmar, is says a lot that after finishing his book, I still needed two bottles of wine and YouTube to figure out what was going on.

    cold-war maritime-history


1,922 reviews364 followers

September 11, 2012

The Thresher came alive in 1963. It was to be a short life. Manufactured from the new “stronger steel—the so-called HY-80 steel which could withstand the pressure of 80,000 pounds per square inch before it would start pulling apart. With a submarine hull built for deeper operation the Navy would get a bonus with the Thresher. Because of her hull strength, in shallow waters she would be able to withstand greater shocks from enemy weapons.” The decision to emphasise depth was controversial. Rickover, in particular, thought the Navy was wasting its money, but the idea was, as a hunter-killer attack sub, that Thresher could hide deep, way below the thermal layers.

Polmar, an excellent naval writer who wrote a terrific biography of Rickover, Rickover: Controversy and Genius: A Biography takes us through the short life of the Thresher. One wonders if any one of several items might have hastened the boat’s demise: the accidental collision with a tugboat in Florida which required rewelding of the outer hull; the explosion tests intended to see what the effects of underwater explosions might be ( “There was no question that the Thresher suffered damage,” he said. “But it was all relatively minor.... The damage we sustained did not impair the ship’s ability to operate, and much of it, such as the damage to vital sonar tubes, we could repair ourselves with our store of spare parts.”)--perhaps one of the internal pipes was damaged; the refit itself, which required cutting holes in the sub to move equipment in and out, and removing and reconnected hundreds of internal pipes; too hasty to test at “test” depth (the maximum depth a sub is never supposed to exceed, in Thresher’s case about 1300 feet. “Below test depth the fittings and pipes on the submarine begin to give way.” Was it any one of these events or a subtle combination thereof?

There was the usual, “golly gee everyone was great, the ship-builders were the best, the crew was the greatest, the boat was perfect, yadayadayada.” (“Captain William Heronemus, testified next. As the repair and ship-building superintendent of the Portsmouth yard, he was intimately familiar with the work that had been done on the Thresher during the past nine months. “I have known no other ship in a higher state of readiness for sea than the Thresher.”) Yet several contrarian tidbits did leak out: the laissez faire attitude of many of the workmen during the refit; the astonishing number of hydraulic vlaves that had been installed backwards (20%, but they got them all corrected before the final dive, yeah right.) A retired CPO who lost two brothers on the Thresher, both CPO’s, Joseph Shafer noted, “ that his brothers were “not sure” that people who worked on the Thresher during her overhaul had done their job. He said there was a jocular attitude of “what’s going to be wrong this time” on the part of his late brothers. David Main, a welder at the Electric Boat yard and a brother-in-law of the Shafers, substantiated the testimony of Joseph Shafer regarding his brothers.” Others testified, “that there had been trouble with a main sea water valve in the Thresher during the nine months the submarine was undergoing overhaul. This was a large valve that admitted water for several of the submarine’s cooling systems. Lieutenant McCoole also said that the air systems of the Thresher had been a continuing problem; that there had been errors in the indicators that showed whether or not the submarine was on an even keel...”

Lieutenant Commander William J. Cowhill, executive officer of the submarine from March 1962, to January 1963 rated the Thresher’s construction and overhaul work at the Portsmouth yard as excellent—“with one reservation, the silver brazing process on piping.” Silver brazing is the process of joining pipes on submarines with silver solder instead of the more common lead solder. The silver solder melts at a higher temperature than lead and gives a much stronger joint. There were hundreds of silver brazed joints in the maze of pipes in the Thresher, many of them on pipes that penetrated the craft’s pressure hull.

Polmar does present alternative scenarios based on the skimpy evidence but all related to the last transmission which described having a “minor problem.” Polmar doubts a pipe fracture letting in a high pressure stream of water as being described as “minor” by any submariner. His suggestion: reactor failure, due perhaps to a stream of water, that might have prevented operating the diving planes (no battery backup?) which in turn led to loss of forward motion causing it to sink, the attempt to blow the ballast tanks which might have failed due to freezing (it was later discovered that blowing the tanks at such a depth was rarely successful.)

I was astonished at the revelations regarding sabotage against U.S. subs. At that time a hose used to test the submarine’s evaporators was cut. The Navy said later that a crew member was responsible, but refused to give any details. Intentional damage was also reported aboard the nuclear-propelled submarine Snook. On December 21, 1959, while the Snook was in drydock at Pascagoula, Mississippi, it was discovered that someone had cut through the elbow of some piping in the submarine. Less than a month after the Snook incident possible sabotage was discovered aboard the nuclear-propelled missile cruiser Long Beach. The then-unfinished Long Beach was at Quincy, Massachusetts, when it was discovered that a 3½-inch armored anti-mine cable had been cut in three places. Although termed “relatively insignificant,” this incident was also carefully investigated by the FBI as well as by Naval Intelligence. Sabotage is usually connected with a deliberate attempt by an enemy agent. However, because of the circumstances it is generally accepted that these incidents were a form of adult vandalism or mischievousness on the part of a civilian worker or possibly naval personnel. It appears the purpose of the sabotage was to delay the ships involved rather than to cause their loss. Numerous other incidents were detailed, but the idea that workmen might do such actions boggles the mind. Rickover testified before Congress (admittedly in a self-serving manner since he was warding off any blame that might have been attached to the nuclear power plant): “ the lack of adequate welding techniques of the critical piping that penetrated the submarine’s pressure hull; the poor management and quality control in submarine construction; and the manner in which the Navy’s leadership made decisions about submarine requirements [including too frequent rotations]. Admiral Rickover was correct in his accusations—there were problems in all of those areas.”

I was a little disappointed in Polmar’s account of the inquiry. It was just a chronological, very brief, recounting of the testimony. The actual transcript ran to more than 1500 pages. I wanted a more detailed and critical review of that inquiry. The formal conclusion was that a silver brazed weld must have given way at test depth resulting in an unstoppable flow of water that rendered the boat uncontrollable and it sank below crush depth.



37 reviews

December 1, 2021

Every time I read a new Cold War book I learn about a new way the US government has managed to lose a nuclear warhead. This time it the sinking of the USS Scorpion (whose loss was discussed briefly alongside the Thresher's), an attack sub which sank with a full set of nuclear torpedoes. One hopes Atlantis has signed the NPT; this was not the only time America has lost warheads in the ocean.

This book has all the expected flaws of a semi-official military history from the Cold War. The writing is dry. Polmar is unwilling to say a bad word about the Navy, its ships, or any of its officers. The narrative is focused like a laser on the immediate facts of the disaster. Discussion of the consequences of the Thresher disaster is limited to a discussion of various submarine safety, escape, and rescue innovations. The reader is with a thorough description of the witnesses called to a naval inquest, but no indication of what it all means. I can't help but wonder if Polmar has elided details. He drops tantalizing details about quality standards at the Portsmouth Naval Shipyard and about ass-covering by officers at the inquest, especially Admiral Rickover, who seems to have deflected investigation from his engineering division's potential role in the disaster- but doesn't follow up.

I don't mean to be overly harsh. This is a reasonably complete accounting of a niche moment in history. Nuclear history buffs will find a lot here.

Be aware that this history isn't fully up-to-date. SOSUS data, declassified decades after publication, suggests that, rather than the flooding theory of the Thrasher's death advanced by Polmar, the death of the Thresher was caused when electrical issues triggered a reactor SCRAM. For more, I recommend this article in the Navy Times (8 April 2013), co-authored by Polmar. The inaccurate theory isn't Polmar's fault- he makes clear that his theory is based on very fragmentary evidence, and his version of the flooding theory seems to have been closer to the SOSUS evidence than the official inquest's theory.


Stefanie Robinson

1,777 reviews6 followers

April 5, 2023

The USS Thresher was a nuclear submarine that was designed to seek and destroy Soviet submarines. The submarine had the most sophisticated weapons systems available at the time, as well as highly sensitive sonar that was capable of detecting ships at great distances. The ship was ordered in 1958, and was built at the Portsmouth Naval Shipyard. It was launched in 1960, and commissioned in 1961. The ship unfortunately met with disaster during deep diving tests, resulting in the deaths of 129 crew members and officers.

I have a few thoughts on this book. I thought that naming the ship Thresher after the shark was pretty neat. I also had no idea that that many people operated a submarine. I am not very knowledgeable about ships, and certainly not submarines, and I have no idea why I assumed there were probably just ten or twenty people on board maximum. Submarines are horrifying to me, simply because you are under all that water and you can't just eject or something when things go wrong. The pressure of the water is scary! Not to mention living in such cramped conditions with that many people. It also really always slips my mind that President Kennedy was actually doing presidential things and dealing with issues like this while in office.

As far as the writing of this book, I found it to be very informative about submarines in general and especially this particular disaster. I had not previously heard of this, and I do love a disaster book. It was entertaining, and it isn't terribly long either. This book is actually currently available on Audible Plus, but if you are interested in reading the physical copy, it is just over 200 pages. I thought it was a really decent book.



5 reviews

January 9, 2022

Norman Polmar's "Death of the USS Thresher" is an incredibly well written, smooth and worthwhile read for anyone interested in submarines, U.S. Naval history, and naval history in general. Throughout the book Mr. Polmar delicately balances the weighty topics of the progression of the submarine throughout U.S. Naval history, the purpose and mission of the Thresher class submarines, the USS Thresher's design and engineering specifications, and the tragic pre- and post-chronology of events to include the investigation that followed the tragedy. While Mr. Polmar was chronicling a historical event, his prose was beautifully engaging as he masterfully wove an impactful thread of the human loss endured by the loss of the Thresher. Mr. Polmar also contextualized this tragedy with other submarine tragedies throughout history, including the Squalus, Tang, Scorpion and several Russian submarines.

Bob Jenkins

101 reviews

April 21, 2023

1963, The Thresher. I do remember this naval disaster as a 9 year old. No details, just that it was a thing.
This book is a follow up for me as I just read a book on the Squalus accident of 1939.
This book goes into the state of submarines of the day. The change over to nuclear power and the new design of the Thresher. It goes into that fateful day, and then most of the book is relating the possibilities of what happened.
The highest probability was that a small water leak developed and for some reason, the nuclear reactor was shut down. In doing so, the submarine could not move fwd. it needs this motion to rise to the surface. Back the;, it took too long to restart a reactor. With no motion, it slowly sank, to crush depth. Then crushed. The remains were found in 8500 feet of water, on the later.
Sad for the country and the navy, but lessons were learned and we moved fwd.
Good book, if you like this kind of history.

Matthew Kresal

Author44 books33 followers

October 19, 2018

As of 2018, the sinking of the USS Thresher remains history's deadliest submarine disaster. Built as the vanguard of the American fleet of nuclear submarines, it's 1963 sinking offered a rare insight into the secretive world of Cold War era submarines. Originally written in 1964 and updated with new information post-Cold War, Norman Polmar's book is a concise account of the Thresher and her loss as well as putting it into the context of other submarine sinkings including the Kursk. Polmar's prose style, however, is quite dry and matter of fact in an almost Joe Friday from Dragnet style fashion. The result is a book that is perhaps less than memorable, more a recital of facts than a compelling historical narrative like, say, Walter Lord's A Night To Remember. On the whole, though, if you have an interest in Cold War submarines, this is almost certainly worth a quick read.


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