Military Review

US Navy Reveals USS Thresher Death Investigation Report (SSN-593)

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US Navy Reveals USS Thresher Death Investigation Report (SSN-593)

USS Thresher (SSN-593) before launching, July 9, 1960


On April 10, 1963, the American nuclear submarine USS Thresher (SSN-593), which had been out for testing the day before after repairs, sank during a test dive. On the same day, the command of the US Navy assembled a commission of inquiry, which was to determine all the circumstances of the tragedy. The main findings and conclusions of the panel have been published in the past, but the publication of the full report has just begun.

The investigation established ...


The commission conducted a survey of persons involved in the development, construction and operation of the lost submarine. In addition, we studied the project and technological processes. In 1963-64. managed to find and study the wreckage of the submarine and collect a lot of important material. Based on all available data, the commission made conclusions.


Submarine at sea, July 24, 1961

The commission determined that at a depth of more than 270 m (the dive target was 300 m) due to a manufacturing defect, a rupture of one of the high pressure water pipelines occurred. The sprayed water hit the electrical appliances, which triggered the emergency protection of the reactor. In addition, due to an unfortunate confluence of factors, the submarine was unable to use compressed air to purge ballast tanks and emergency ascent.

Having lost speed and the possibility of surfacing, USS Thresher (SSN-593) continued to gain water and dive. At a depth of more than 700 m, a solid hull was destroyed, resulting in the death of 129 crew members. The submarine fell apart into six parts, which sank to the bottom in an area with a diameter of 300 m. During the submersion, the escort vessel USS Skylark (ARS-20) received several short messages.

Privacy issues


Subsequently, the public was informed about the main circumstances of the tragedy and the reasons for the death of the submariners. However, the full report of the commission of inquiry remained secret for several decades. More than 1700 sheets with interrogation protocols, examinations, diagrams and diagrams remained inaccessible to the public.


In 1998, the command of the Navy decided to disclose data on the death of USS Thresher (SSN-593), which occurred 35 years ago. The declassification process dragged on, and by 2012 only 75% of the report had passed the required procedures. After that, the command decided to suspend the work. However, the publication of documents was not ruled out - but according to the rules of the Law on Freedom of Information.

In April last year, retired Captain James Bryant, former commander of one of the Thrasher-class boats, submitted a request to publish the report. He asked to speed up the work so that the document would be available by September - for the opening of a memorial to submariners at Arlington Cemetery. Over the next few months, bureaucratic procedures continued, as a result of which the commission's report remained closed to the public. The monument was opened without complete data on the death of the submariners.


Rejected, J. Bryant appealed to the District Court for the District of Columbia in July. In February 2020, Judge Trevor N. McFadden delivered a judgment. He ordered the Navy to complete the procedures for declassifying the report and start publishing it. 300 pages of the report were to be opened monthly; the first part was required to be released by the end of April. Thus, by the end of autumn, the public could fully familiarize themselves with the documents of the investigation.

In May 2020, it became known that work on the report was temporarily suspended due to the COVID-19 pandemic. In connection with the introduction of quarantine measures, the Navy could only continue operational activities, while other activities were temporarily canceled. In mid-July, they announced the resumption of work. On September 23, after several decades of waiting, the first part of the report was released.

Open data


The first file in the public domain includes 300 sheets. In preparation for publication, the document received appropriate notes. In addition, the personal data of the interviewed persons and some other information were removed from it.


One of the damaged parts of the case

The published 300 pages are collated out of order. They include a list of documents included in the report, a list of materials and material evidence, as well as documents on the formation, composition, etc. commission of inquiry. At the same time, the sections with facts, versions and conclusions in the original are located at the very end of the report - but they were inserted at the beginning.

Thus, already now you can familiarize yourself with a list of 166 facts describing the last trip of the submarine. It reflects the main organizational issues, lists the crew and civilian specialists, the progress of the tests, as well as information about the design, construction and operation of the submarine. Then 55 points follow with versions and conclusions. Based on the results of this part of the report, recommendations are issued for the naval forces and the shipbuilding industry, aimed at eliminating new such disasters.


Destroyed nose of a light hull with GAS units

Most of the published materials are recordings of interrogations of witnesses. During the investigation, almost 180 people were interviewed, these are design and construction participants, former crew members of the USS Thresher (SSN-593) and sailors from the USS Skylark. The first 300 pages included only a small part of the protocols, just over 20.

Future publications


The court ordered the Navy to publish 300 pages from the commission's report every month. This means that an entire document of over 1700 pages will be split into six parts. It was originally planned to publish the entire report this year, but after the known events, it will not be completed until next spring. However, the public and historians have already waited almost 60 years, and a few extra months have no effect on anything.


A section of one of the pipelines damaged by a boat sinking

As follows from the published table of contents, most of the future publications will be devoted to the questioning of witnesses. They may be of interest to researchers or participants in those events, but their publication will have to wait.

New Details


It should be noted that the main versions of the disaster and the general conclusions of the commission were known earlier. The published report of the investigation only reveals this issue in more detail, and also supplements the conclusions of the commission with a mass of primary information, a significant part of which has so far been closed. New details may be of some interest in context storiesas well as the construction and development of the American sub fleet.

Thus, 57 years after the sinking of the submarine USS Thresher (SSN-593) and after two decades of bureaucratic delays, the US public has the opportunity to get acquainted with all the materials of the investigation. In the near future, by the end of October, the US Navy should publish the second part of the report, and then new data will be received. They will show what problems the American nuclear submarine fleet faced in the early stages of construction, what they led to and how they eventually dealt with them.

The first part of the report:
https://www.secnav.navy.mil/foia/readingroom/HotTopics/THRESHER%20RELEASE/THRESHER%20pg%201-300.pdf
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US Navy
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  1. Undecim
    Undecim 30 September 2020 18: 31 New
    14
    In addition, due to an unfortunate confluence of factors, the submarine was unable to use compressed air to purge the ballast tanks and an emergency ascent.
    Such an "unfortunate confluence of factors" was someone's negligence, due to which strainers were not removed in the purge lines of ballast tanks before sea trials, which are installed during installation to avoid damaging the valves with debris.

    As a result, when an attempt was made to emergency blow off the ballast, ice formed on the nets (as you know, when the gas expands, its temperature decreases), which clogged the pipelines and it was not possible to blow the ballast.
    1. beeper
      beeper 30 September 2020 20: 35 New
      +2
      hi I recalled the accident of the Komsomolets submarine, when the compressed air used to blow the ballast tanks instead of the powder generators (provided specifically for emergency emergencies), bursting out of the burnt high pressure pipeline and becoming an additional powerful source of oxygen, caused the effect of a "blast furnace" in the blazing the seventh compartment ...
      If then on "Thrasher" there were the same gunpowder generators, then it is possible that people and the boat could have been saved — after all, the filter grids would probably not have frozen from the expanding hot powder gases ?! Wasn't that what our designers took into account the lessons of the death of "Thrasher" ?! winked
      Back in 1963, the Tekhnika-Molodyozhi magazine told about this accident, and the next year, in the panorama section, it published a small note with a photo of the rudder remnants found at the bottom of the ocean.

      PS Does it seem to me, or is it actually on the photo of the damaged part of the "Thrasher" hull, next to the bent pipe, the body of a submariner is visible ?!
      1. Undecim
        Undecim 30 September 2020 20: 47 New
        +2
        This is part of the sonar nose cone.
        Very similar, but not a corpse. You can imagine the size of the fairing from the first picture, there are people down there. The aspect ratio shows that this is not a diver.
    2. Dmitry V.
      Dmitry V. 1 October 2020 09: 09 New
      0
      Quote: Undecim
      As a result, when an attempt was made to emergency blow off the ballast, ice formed on the nets (as you know, when the gas expands, its temperature decreases), which clogged the pipelines and it was not possible to blow the ballast.


      Shouldn't they have first experienced a test dive in shallow water, where this defect would have been revealed under less tragic circumstances?
      1. Avior
        Avior 1 October 2020 09: 42 New
        0
        the boat should not float up from the depth at all, while it jumps out of the water and the consequences can be in the form of damage
        1. Dmitry V.
          Dmitry V. 1 October 2020 11: 47 New
          0
          Quote: Avior
          the boat should not float up from the depth at all, while it jumps out of the water and the consequences can be in the form of damage


          The boat, first of all, after leaving the base, is differentiated at a shallow (periscope) depth (balanced) and before diving to a great depth - it has zero buoyancy, dives under the horizontal rudders.
          1. Avior
            Avior 1 October 2020 11: 49 New
            +1
            to the periscope from the depth it comes out with rudders, then blows through the tanks and floats, as far as I understand
      2. Undecim
        Undecim 1 October 2020 10: 42 New
        0
        Shouldn't you have experienced a trial dive in shallow water first?
        They tested it in shallow water. There was no need for an emergency blowdown of the ballast tanks.
  2. ZEMCH
    ZEMCH 30 September 2020 18: 38 New
    +2
    There is a human factor behind almost all accidents in the Fleets (of any country). Man will always be the weakest link in any perfect system.
  3. Krasnoyarsk
    Krasnoyarsk 30 September 2020 18: 41 New
    0
    I don’t understand - what will the public gain from knowing the details of the sinking of the boat and all the materials of the investigation?
    For specialists: builders, operators, designers - yes, but for the public?
    1. lelik613
      lelik613 30 September 2020 19: 32 New
      +3
      It was necessary to put an end to it.
    2. The leader of the Redskins
      The leader of the Redskins 30 September 2020 21: 02 New
      +2
      But just imagine if the families of the submarine "Kkrsk" filed with any regional court and that one OBLIGEDED the Navy to publish the documents on the investigation. You look at the relatives' hearts relieved, and the souls of the sailors calmed down.
      1. Firelake
        Firelake 30 September 2020 22: 59 New
        +1
        It doesn't work in Russia.
      2. Krasnoyarsk
        Krasnoyarsk 1 October 2020 00: 20 New
        +2
        Quote: Leader of the Redskins
        But just imagine if the families of the submarine "Kkrsk" filed with any regional court and that OBLIGED the Navy to publish the documents on the investigation. You look at

        Actually, the word "public" means something else.
  4. Avior
    Avior 30 September 2020 23: 56 New
    +9
    From what I read about the sinking of the boat, I brought out several reasons for myself, the coincidence of which became fatal - except for the most fatal damage that led to the shutdown of the reactor. In general, the boat was lifted to the surface by the rudders, and for this a course was needed.
    1. The rector did not allow a quick restart. Although in fact there was such an opportunity, and then it was introduced, on Thresher it was not foreseen.
    2. It was possible to provide a course for a while, if the steam was not vented at the time of the reactor shutdown, as required by the safety instructions.
    3. The officer in charge of the reactor stayed ashore for personal reasons and was replaced by a new one who blew off steam strictly according to instructions. The one who remained later said that with a high probability the steam would not bleed off and the boat would have been running for some time. But this is an afterthought, of course. I remember there was a tragic story with one of our diesel submarines, when water got into the RDP and it was necessary to quickly close the shut-off valve. The sailor, who had recently been transferred from another boat, pressed on the handle so that he bent the handle. Only on the other boat, the valve closed in the other direction. S-80, if I'm not mistaken.
    4. Blowing failed, because, firstly, the protective nets were not removed, and secondly, air with high humidity was pumped into the cylinders, the expansion of which during blowing led to a large formation of ice on the nets - the gas cools down during expansion, as anyone who had to make soda knows from a carbon dioxide fire extinguisher, or, God forbid, really extinguish the fire - fingers freeze to the bell.
    After Thresher, the problem with the meshes was solved, and filters were installed to dry the air when pumping into the cylinders.
    And the last thing. Probably, if the depth at the test site was less - it is assumed that the destruction of the hull occurred at more than 700 m, the tests were carried out up to 360 or 380, the boat could lie on the bottom and eliminate the problem with the reactor or with the purge - the time factor was important, Threscher drowned very fast.
    But history does not know the subjunctive mood :(
    1. Dmitry V.
      Dmitry V. 1 October 2020 09: 14 New
      0
      Quote: Avior
      Probably, if the depth at the test site was less - it is assumed that the destruction of the hull occurred at more than 700 m, the tests were carried out up to 360 or 380, the boat could lie on the bottom and eliminate the problem with the reactor or with the purge - the time factor was important, Threscher drowned very fast.


      Here I am about the same, why the test dive was not carried out at a depth not exceeding the safety margin of a solid case.
      1. Avior
        Avior 1 October 2020 09: 23 New
        +2
        In principle, they checked the boat for the maximum design immersion, something about 360-380 meters.
        There should have been a margin so that if they miss with depth, they would not hit the bottom.
        But the margin exceeded all reasonable limits.
        It's hard to say why, I have never seen an explanation.