Talk:USS Thresher (SSN-593)

Untitled

The two sizes for the debris field don't agree - 134,000m² and 400 square yards. GreatWhiteNortherner 08:48, Jan 1, 2004 (UTC)

They agreed when the Imperial measurement read 400 yards square, which means a square 400 yards on a side. I hope whoever changed it from "yards square" to "square yards" went down and actually swept all that debris into the new 60x60 foot area. (I've reverted the change.)--the Epopt 15:47, 1 Jan 2004 (UTC)

Technicians or engineers?

Not sure if civilians were technicians, engineers or both.Fg2 01:52, Aug 7, 2004 (UTC)

Per the bios in the external link at the bottom, and other sources, the Portsmouth employees were a mix of techs and engineers, while the NOL, Sperry, and Raytheon employees were engineers. I also corrected the affiliation of the NOL employee, which is now consistent with numerous other sources (the error was probably copied from the Arlington Cemetary site http://www.arlingtoncemetery.net/uss-thresher.htm which corrected it in 2005). The history of NOL, "The Legacy of the White Oak Laboratory", NSWC, Department of the Navy, Dahlgren VA, 2000, p. 55, refers to a Naval Ordnance Laboratory scientist, Don Kuester, lost on board the USS Thresher in April 1963. Mattfiller 23:00, 21 May 2006 (UTC)

Folk tale

I deleted this tale:

One of the final communications from the Thresher was reportedly radioed by the executive officer "Tell the boys from General Dynamics that they fucked up". The crew had apparently realized that the submarine was doomed after repeated attempts to empty the ballast tanks and surface had failed.

It is utterly impossible for anyone to radio anything from Thresher's test depth, and I find it hard to believe that the executive officer of a submarine in distress is taking the time to send droll messages to "the boys from General Dynamics" (not Electric Boat?). If 208.180.17.13 can cite any credible evidence for this unbelievable and hither-to unknown story, I will publicly apologize. ➥the Epopt 14:36, 18 Jun 2005 (UTC)

Concur that the "every guy in SWO heard this" is still FOAF. Looking for official reports, documentation, even the name of a credible witness. Jinian 17:35, 18 Jun 2005 (UTC)

I was thoroughly briefed on the Thresher disaster, both in Naval Nuclear Power School and as part of my qualification in SUBSAFE/Level One Quality Assurance. I will state positively that no such message as described above was ever sent; the last communication received by Skylark was "Experiencing minor problem. Have positive angle. Attempting to blow." The next identifiable sounds were the well-known noises made by a submarine falling through crush depth. Today is Saturday; Monday morning I will repeat this story to the many surface-warfare officers I work with (most of whom are in their forties so they would have been in "surface warfare officer (SWO) school in the early to mid 1980s"); Monday evening I will describe their reactions here. ➥the Epopt 17:45, 18 Jun 2005 (UTC)

The following is in retort to some of the above points. Course material from surface warfare officer (SWO) training classes at Newport RI, including official US Navy reports, tapes, and transcripts, indicated that the malfunctions aboard Thresher did not present themselves in a sudden or mysterious way. Rather, events occured over an extended period during which her crew repeatedly struggled to surface. Thresher attempted to surface with forward propulsion and a positive degree "up bubble" on the planes. Unfortunately, Thresher was handicapped by having her ballast tanks full of seawater after numerous failed attempts to blow. Ultimately, Thresher was unable to maintain positive bouyancy and subsequently sank in over 8000 feet of water. The quoted taped message was received while Thresher was near the surface immediately before her final uncontrolled dive. It was not the final communication from Thresher. The "droll" message was only sent after the situation was obviously beyond remedy; it is not beyond reason for a LCDR to dispense with communication protocol upon the realization that his life, and the lives of over 100 men, were doomed. As for the question of why the quote was directed to "the boys at General Dynamics", Electric Boat was, and still is a division of the General Dynamics Corporation. The assertion that the quote "Tell the boys from General Dynamics that they fucked up" was one of the final communications from Thresher, along with the above accounts, was corroborated by separate personal interviews with three Naval officers (one retired, two active duty surface line officers) that were in SWO school classes and were witness to these documents and recordings in the early to mid 1980s. Note also that officers attending SWO school in that period are currently in their late 40's and early to mid 50's. — Preceding unsigned comment added by 208.180.17.13 (talk • contribs) 19:15, 18 June 2005 (UTC)

I personally like the strong statement "Thresher was near the surface". Going up is canceling of the test, it absolutely should be reported by captain. Since his report of 9:02 tells nothing about it, we may assume that at least a 9:02 the ship was below 300m depth and had low speed. There was told to be implosion noise at 09:18. This allow to state the question, could 16 minutes be enough for Thresher to jump from 300m depth to the surface (more accurately, from a bit below 300m to a bit below surface) and then dive back to collapse depth? 79.111.218.128 (talk) 19:21, 22 September 2011 (UTC)

Absolutely none of which is can be looked up by anybody but you — we have nothing to go on but your word. Until you cite a verifiable reference that we can look up, we cannot add your tale to this encyclopedia. Personal interviews, unless they are published so that they can be found by third parties, are not acceptable sources. ➥the Epopt 20:23, 18 Jun 2005 (UTC)

My sources are reluctant to be identified. Apparently, there is some question regarding the official status of the material they saw. I'll wait to see what your superiors in the Navy have to say, although your indignance doesn't give me much confidence in your impartiality. Unless somebody with more time can view the actual documents (freedom of information act?), I suspect certain people won't even take a Naval officer's word as truth.

It's not a question of believing one guy's recollection of a story, but whether or not such a memory is appropriate reference material. Undocumented tales - undiscovered by someone with more time (i.e., the author of "Death of the USS Thresher") - seem inappropriate to an encyclopedia. Obviously, if sourced material surfaces, it would be included. Without sources, perhaps you can craft a "Reportedly, one of the last comms..." and make the apocryphal nature of the story evident. Jinian 04:01, 19 Jun 2005 (UTC)

Let me confirm your suspicion: you are absolutely right when you say that without viewing "the actual documents ... certain people won't even take a Naval officer's word as truth." Those certain people have crafted the fundamental policies of this encyclopedia. We don't take anybody's word as truth, even those paragons of veracity, Naval officers. We only take verifiable published sources as truth. Until you have a page number in a published work (the Proceedings of the Naval Institute would be good) your anecdote remains apocryphal. ➥the Epopt 14:14, 19 Jun 2005 (UTC)

I'll wait to see what your superiors have to say. The fact remains that the recordings exist, and those words were heard on that tape by at least 3 seperate men. Note that these are not recollections of a story; they are recollections of the XO's own words on tape. In addition to this, documents detailing Thresher's loss in nauseating detail also exist. In light of this fact, Polmar's book (which is not even cited) should not be the primary source for what should be a thorough article. As it stands, this article is presently a mere rehash of material from websites.

Two LCDRs and two CDR currently working at SPAWAR Old Town, all of whom went through SWO school in the mid- to late-eighties, never heard of anything like your story. They heard tapes of submarines operating and submarines being sunk, but no dialog whatsoever. One of the CDRs quizzed me at length as to why I [sic] thought that the Navy would waste time playing such a tape to surface officers. After my explanation, he indicated that he would check out this Wikipedia thing ... so that's one good thing to come out of this discussion.

So the score stands at three officers unwilling to be named (a slight reduction from "every officer in surface warfare officer (SWO) school") who allegedly heard this tape against four officers whom I didn't ask if I could name but who think the story is ridiculous ... and the inarguable facts (a) that it is impossible to "radio" from test depth and (b) that I get exactly zero (0) Google hits for either of the searches

submarine "the boys at General Dynamics" 
submarine "the boys from General Dynamics" 

I think we'll stick with Wikipedia policy: no unverifiable material allowed.

By the bye, I'm a civilian contractor; the rank-equivalence is fuzzy, of course, but I call Lt.Cols./CDRs and under by their first names, Cols./CAPTs by rank-plus-last name, and only say "sir" to guys wearing stars. ➥the Epopt 03:39, 21 Jun 2005 (UTC)

I'll add that I asked some of the target audience (SWOS in the 1980s) as well and got a similar reponse. Mainly, "HUH? Who could have radio'd from depth?" But the consensus was that it was a folktale and not real. Jinian 00:19, 22 Jun 2005 (UTC)

I'm not sure tribal memory within the SWO - surface warfare officer - community is the most authoritative source. How come nobody within the submarine community ever heard this story? The Thresher was widely discussed for decades afterwards, especially on sister ships of the same class (such as mine). During the period of great tension between EB and the submarine community in the early 1980s, anything that negative about EB would have been widely repeated. Furthermore, I never heard a submariner refer to the Electric Boat shipyard by the name of its' parent, General Dynamics -- it was always "EB". Finally and most tellingly, Portsmouth Naval Shipyard (where Thresher was built and then overhauled just before the accident) took the blame. I can think of no reason the XO would point the finger at a totally unrelated shipyard in his last words. For more history on Thresher's maintenance history, see http://www.subsim.com/ssr/thresher.html and http://www.globalsecurity.org/military/library/news/2003/04/mil-030414-navsea02.htm

68.163.249.43 02:00, 14 December 2006 (UTC)I'd be willing to be that the XO, as the senior Nuke on board, would have had his kiester back aft, trying to contain the flooding or restart the plant, not casting aspersions about Electric Boat (or, more correctly, Portsmouth Naval Shipyard, which had just performed the overhaul) over the UQC. The ONLY rumor I've heard is that a junior officer was calling off depths and pressures right up until the end, but I've never seen this confirmed anywhere. As guilt-striken as the Navy was about Thresher (and rightfully so), it would be almost impossible to hush this sort of thing up for so long. (Mike Chapman68.163.249.43 02:00, 14 December 2006 (UTC))

I suggest our expert check out his story out with some submariners.A. B.

The story concerning the comment on General Dynamics is ridiculous. Thresher was designed and built by Portsmouth Naval Shipyard (PNSY). The people at PNSY took exceptional pride in that fact. At the time of her conception Thresher was conceived as a superior alternative to USS Tullibee, a smaller, slower, electric motor driven submarine of different design, designed and built by Electric Boat (EB)in Groton, CT. Thresher was bigger, faster, deeper diving, and steam-turbine driven with unique sound isolation features which gave her capabilities no other submarine had. She was viewed by Portsmouth as their salvation in their ongoing competition with EB, which had been until then used almost exclusively by BUSHIPS for designing and building the lead boats in the nuclear fleet. The success of Thresher would make PNSY the lead 'yard' in a new, superior class of submarine. In fact, there was a large sign posted on the ship's company's work/berthing barge during construction which stated "USS THRESHER, Portsmouth's Own". The only part of Thresher that was remotely related to Electric Boat was the S5W reactor plant which was primarily designed by Westinghouse Electric, in conjunction with EB to some degree for the Reactor Compartment and the Auxiliary Machinery Space compartment piping for the Skipjack Class submarines, and later used in several classes of submarines built elsewhere which used the S5W reactor plant. Finally, no matter who the builder was, the thought that anyone, with their ship in extremis, sinking out of control, would grab the UQC (underwater telephone) to send a stupid message such as that described above,is a sea story that could only be believed by an ignorant landlubber. EFM 4/27/06

Interestingly enough, Admiral Rickover had very little input as to Thresher's design. Since the S5W plant was a proven design, he was merely in charge of the training of the engneering crew and the selection and approval of the commanding officer, XO and Chief Engineer. Thresher used a "rafted" deck in the engine room for sound-isolation purposes, and though Rickover had serious doubts about the engineering, he had very little input as to the design, much less than he had enjoyed with the Skipjack class (which debuted the S5W plant.) He was very concerned about the great depths to which this class of ships would venture -- the Skipjack class had a maximum depth of about 700 feet, about half that of Thresher.

It's also interesting that Portsmouth got the contract for the lead ship in the class. It's well known that Portsmouth was offered the chance to design and build Nautilus, but that the yard superintendent at the time turned Rickover down -- he had too much work backlogged already. The story is that Rickover used the superintendent's own phone to call the GM of Electric Boat, who promptly accepted the challange. Most of the submariners I've known shuddered at the thought of having work done at Portsmouth. Being folks imbued with caution and long memories, they remember that Squalus sank after coming out of overhaul at Portsmouth, as did Thresher. (MBC02:09, 14 December 2006 (UTC))

Garbled message

It's been a few years, but I read about a garbled message from an underwater phone to a support ship. Maybe this is an embellishment on that? Pete 03:46, 21 Jun 2005 (UTC)

Thresher was in contact with Skylark throughout her tests. The last intelligible gertrude (sound) transmission received by Skylark was "Experiencing minor problem. Have positive angle. Attempting to blow." ➥the Epopt 23:11, 21 Jun 2005 (UTC)

It is possible that this was the "garbled message" left out of civilian books for the sake of decorum.

If so, it was also left out of all Naval records as well. The story is impossible, unbelievable, an insult to the XO, unverifiable, and — in my arrogant opinion as someone who has spend over 25 years working in, on, and with submarines — fictitious. ➥the Epopt 15:49, 23 Jun 2005 (UTC)

Message

I have heard this recording, although it was at OCS (Newport, RI) in 1983. I can't remember the exact quote, but it was to the effect of "the guys at general dynamics fucked up". I believe the submarine was in contact via low freq. radio - although I was not a bubblehead, myself. This was over 20 years ago, but the recording left an impression. (unsigned comment by IP:4.88.10.66)

Sorry, but no matter how many anoynomous "I heard it, but can't confirm" I see, I still don't believe you. Unverifiable heresy does not belong is unencyclopedic. Jinian 17:24, 4 January 2006 (UTC)

Plus, isn't LFR morse-code, not voice? Ralph 1March06

VLF (very low frequency) radio does not penetrate water to the Thresher's depths. As I recall, it's receive-only alphanumeric data -- no voice. See http://en.wikipedia.org/wiki/Vlf and http://en.wikipedia.org/wiki/Communication_with_submarines A. B.

Crush Depth

Anyone know what the actual lower limit on this class of Submarine is? I'm assuming it's lower/higher (...not sure what the correct nominclature is) that 8000m, but the article never actually mentions it.

I don't know if that data is still classified or not, so I googled for it, and http://web.ukonline.co.uk/aj.cashmore/usa/submarines/thresher/ states "diving depth is 1200' and crush depth is 1950'." ➥the Epopt 14:51, 6 March 2006 (UTC)

As a member of the ship's commissioning crew and one who rode the ship through her trials up until August, '61, Test Depth, as it is termed,the maximum designed operating depth, was 1,300 feet. Collapse depth, as is is termed, was not a generally published figure. I know it was less than 2,000', but don't know the exact number. There are people familiar with that class of submarine who do know. 27 April 2006

Internal waves

I deleted this new material:
"Oceanographers have conducted studies that examine under water waves called "internal waves," and these usually occur between thermohaline (temperature and salinity) gradients. These thermohaline gradients reflect sonar pulses, which makes it an ideal area for submarines to cruise silently. Concurrently, the USS Thresher could have been cruising silently on a thermohaline gradient while an internal wave tossed the submarine (internal waves can easily be the size of a football field), sending it to an area with intense pressure. This pressure would make the submarine implode and the debris would sink to benthic regions."
Comments:

1. There's no evidence -- just speculation -- that this phenomenon occurred in the Thresher's case.
2. There's no indication in the U.S. submarine community that any U.S. submarine has ever experienced unexpected large depth excursions due to underwater turbulence. I never encountered one nor heard of anyone else encountering one.
3. The Thresher was on sea trials after an overhaul. Sea trials after extensive maintenance are the most dangerous time for a submarine, which is one reason the U.S. Navy will nowadays sometimes have escort vessels and rescue equipment nearby. The general held belief within the Navy is that an improperly weld or silver brazed joint made during the overhaul somewhere in the hundreds of feet of pressurized seawater piping within the engineering spaces subsequently failed. If such a failure is going to occur, it will probably occur during sea trials.
4. A Google search ["Internal wave" AND Thresher] turns up numerous speculative comments within various oceanographic articles on internal waves that mention the possibility that Thresher may have been lost to an internal wave. Most of these passing comments make no mention of the original source of this notion and none of them make any mention of the accident investigation and report.
5. The most pronounced gradient occurs somewhere between 100 and 200 feet. Were Thresher at this depth, it would have taken a depth excursion _far_ in excess of the "size of a football field" to take Thresher to crush depth. Even if Thresher were operating at its' maximum operating depth, there would still be several "football fields" between it and crush depth.
6. Submarines do operate with neutral buoyancy, but they could add quickly substantial buoyancy to counteract such a wave. This was true even prior to the post-Thresher SUBSAFE modifications to allow blowing ballast tanks much faster. By contrast, an internal seawater piping failure can dump many tons per second of weight into the boat if it occurs near test depth -- this is true even of a very skinny pipe. Blowing ballast tanks (even with SUBSAFE emergency blow modifications) may not save a boat if the flooding goes unchecked for very long. (Because of this, another SUBSAFE modification allowed the engineering officer of the watch to rapidly shut all hull valves in a matter of seconds in the event of flooding.) -- A. B.

inclusion of officers and enlisted names

I question whether or not the inclusion of the names of the sailors aboard the ship when it sank is really a good thing for this article. Is this encyclopedic information? Does it add to the article? I would like to remind everyone that wikipedia is not a memorial. While I am interested in such topics as this one, I just want to make sure that this article maintains a neutral point of view. What does everyone else think? -- malo (tlk) (cntrbtns) 06:09, 24 May 2006 (UTC)

I can see your point -- it makes the article longer. On the other hand, I'm against removing this information from the Wikipedia.

Articles can be too big, but the Wikipedia can never be too big (well almost never -- there are some limits). Wikipedia accommodates its ever-expanding accretion of information by splitting articles off into smaller articles. Perhaps one approach would be to put this list on a separate article linked to this one. It could also include a list of the memorials to the Thresher (buildings named after crew, etc.). The fact is that the loss of the Thresher had a big impact on the American people when lost in 1963 -- as big as the loss of the space shuttle Challenger in 1986 and bigger than the loss of the space shuttle Columbia in 2003. The names of these men and their stories were plastered all over the newspapers for months as was the aftermath of the accident. It wasn't until the Kennedy assassination that the Thresher disaster faded from the national zeitgeist. I remember the news bulletins, programming interruptions and lowered flags from my childhood.

By the way, a brief discussion of the accident's significant impact on the American public should probably be included when someone has time to research it and write it up.--A. B. 16:50, 24 May 2006 (UTC)

As I realize that this page is not intended to be a memorial, as being a granddaughter of Donald E. Wise, it does make me feel better to know that when talking about the USS Thresher disaster the officers are as important to readers as the ship they were on.KeriDBeri (talk) 04:28, 13 November 2008 (UTC)

Soviet Scalar EM Weapon Lunacy

I rolled back an attempt to add the "Thresher was deliberately sunk by the Soviet Scalar Electromagnetic Weapon" lunacy. I am quite familiar with that particular conspiracy theory, as my dad was an earnest proponent of it. It can be summarized as "the Soviets could (can? [cue ominous music]) use buzzwords to cast magic spells," and there is no evidence whatsoever to support it.

I would support the creation of an article describing the fantasized Soviet Scalar Electromagnetic Weapon, and perhaps even a mention in this article that a dozen or so, um, er induhviduals believe that Thresher was sunk by it, but I oppose any attempt to present such as claim as a fact, or even as a serious conjecture. ➥the Epopt 18:27, 9 August 2006 (UTC)

nine hundred north

Hi,

i'm on my way writing the german article into featured status. One question occured to me: is there any point i don't unterstand with the last garbled message "nine hundred north" (if it was exaclty like that)? Any hidden reference to test or crush depth i dont see? Thanks, --schlendrian •λ• 19:00, 20 September 2006 (UTC)

Could have saved the Thresher?

Mr. McCoole's oft-repeated claim that he would not have closed the Main Steam stops, and thus kept main propulsion avalable, does not stand up for two reasons.

1. The S5W plant had a three position switch in Maneuvering that controlled the stops. Until procedures were revised following Tresher's loss, the switch was kept in "Auto" which means the stops would close automatically on a reactor scram, too quickly for an operator to prevent. Keeping this switch in Manual, so they didn't automatically close was one of the post-Thresher changes.

2. As the MPA, Mr. McCoole was responsible for training his people. There's no reason to believe they acted contrary to his training, and no reason to believe he would have done any different.

H.A. Joyce, Jr (fmr MM1(ss) 1971-1980, and son of ETC(SS) H.A. Joyce, plankowner and RC Div. Chief, USS Thresher, pre-comm thru 04/08/63)

Regarding 1. Before we dismiss Lt. McCoole as a liar or victim of memory deluded by wishful thinking, perhaps there's an intermediate position. Your critique assumes that the stop switch was on "Auto" at the time of the SCRAM because this is what Navy procedure called for. I gather there was no lock out in place that would have prevented McCoole from moving the switch to manual at his discretion. Wouldn't a sub at or near test depth, especially with depleted batteries, present an intelligent time for an experienced Reactor Control Officer to do so? The fact that Rickover thought of it after the fact and changed policy doesn't mean somebody(s) in the fleet didn't think of and implement it first. In fact, the line from the article "Nothing enraged Rickover more than this argument. Common sense, he argued, would prove this to be untrue." suggests that just such a scenario was very much the case. I doubt the history of the Navy has no instances where experienced officers deviated from standard procedure.

Regarding 2., As to training, would Lt. McCoole finish imparting all of his knowledge to his subordinate the moment he boarded, or a day, week or months later? More importantly, training and experience overlap somewhat but are hardly the same thing. Lt. McCoole stated that he had more experience, not training, than his subordinate. Surely you aren't suggesting that training held equal, experience is irrelevant in a combat team, and is not prized because it results in better choices and performance in difficult circumstances.

Mark Davis, Saw a submarine once.

WarQuestions 00:36, 4 October 2007 (UTC)

Batteries

Speaking of batteries, the article says "The logical action at this point would have been for Harvey to order propulsion shifted to a battery-powered backup system." and then just carries on. User WarQuestions stats above that the batteries were depleted. Can anybody shed more light into this? The nuclear power plant should both keep the sub running by itself, and probably recharge the batteries, even when submerged, right? So, why could Tresher not use her batteries for propulsion? If they were depleted, then again, why? thestor (talk) 18:52, 21 September 2008 (UTC)

As far as I've read, the batteries were not depleted before the fatal dive - that would probably have been a "no-go" item. The batteries were known to be finicky, however.

There are two points here -

First, a submarine equipped with a reactor has immediate problems when the reactor is shut down unexpectedly. Certain equipment has to be kept running, including lube oil and hydraulic pumps, and the pumps that move water through the reactor itself. Following a SCRAM the electrical loads shift to the battery, which is smaller than that carried on conventional submarines. Normal procedure would be to rise to periscope depth, and, if the reactor could not be restarted promptly, to begin snorkling so that the diesel engine could be started. This in turn would supply power to the ship until the reactor could once again be started. The battery was small enough that it would be depleted rapidly without the reactor or the diesel running.

Second, at test depth where Thresher's problems began, Captain Harvey would certainly have ordered a "switch to EPM" (the emergency propulsion motor) following a SCRAM. However, the EPM was for emergencies only, and didn't have enough horsepower to propel Thresher back to a safe depth. Thresher was probably neutrally buoyant at that part of the dive; flooding in the engine room would certainly have made the ship increasingly negatively buoyant, a further obstacle for the EPM to overcome. It's also possible that the EPM itself failed - there were reports that at great depths, the EPM would bind up because of insufficient clearance, made worse by the compression of the hull at 1,300 feet. Or it could have been rendered useless by the electrical short-circuits caused by the flooding.

It's said that engineering disasters follow a "three-legged stool" model - three things have to go wrong for tragedy to strike. In this case we have a (supposedly minor) flooding casualty, which caused a reactor SCRAM, followed by blockage of the air lines between the air banks and the ballast tanks due to freezing moisture caused by the emergency blow.

151.203.212.138 (talk) 20:10, 4 January 2009 (UTC)

Spontaneous reactor re-starts after SCRAM

I've edited the last half of the sentence

"This was done to prevent an over-rapid cooldown of the reactor, which could actually restart spontaneously and go out of control if the core was cooled too quickly."

to read

"This was done to prevent an over-rapid cool-down of the reactor."

I'm not aware of any data reporting a reactor restart following a scram. When scrammed, the safety rods are totally in and there is no way fissioning could restart because the rods overwhelmingly absorb all neutrons buzzing around. That is precisely what they are designed for - to absolutely prevent a chain reaction under any circumstances.

Mark Davis

WarQuestions 20:34, 4 October 2007 (UTC)

I'll leave the edit intact, but...

Even when the control rods are fully re-inserted following reactor criticality, fission is only attenuated. The rods do not "absorb all neutrons buzzing around", they only attenuate neutron flux to well below the point of criticality. The reactor continues producing decay heat, albeit at a fractional rate, for some time following a SCRAM. It's not as simple as snapping a switch, it's more like your car rolling to a gradual stop after you take your foot off the gas, or switch off the ignition. That's part of the reason that post-SCRAM loads on the battery are so high - the main coolant pumps have to continue running.

If the temperature of the reactor coolant is lowered quickly enough (as it could be if steam were withdrawn from the secondary side for many minutes in an attempt to drive the ship to the surface), then the cooler, denser coolant would trap more free neutrons, causing reactor power levels to rise dangerously, even with the rods inserted. This is known as a "cold water accident" and it's particularly nasty because it can happen quickly and is nearly impossible to control. This is no doubt why the main-steam-stop switch would have an "auto" setting (though it's placement in auto or manual on Thresher will never be known), to keep the heat in the primary system.

Admiral Rickover later changed the post-SCRAM procedure to allow steam to be withdrawn in limited quantities, to allow the limited use of the main propulsion system for an emergency such as this.

--Mike Chapman

Mr. Chapman, that's just silly. Rods don't just "slow down" fission, they make it negligeable. When fully inserted they drive the reactor sub-critical. I think you are confusing decay heat generation, which doesn't go away immedeately, with the concept of criticality. Reactors are designed so that, with all rods inserted, they will remain sub-critical under all forseeable conditions, even if other components fail. The REAL concern is that a rapid cooldown induced by drawing off steam after the reactor is scrammed will cause excessive cooldown, lowering both primary and, most importantly, secondary temperature. As secondary temperature lowers, steam pressure lowers. If it gets low enough, things stop working. So, once you restart the reactor, before you can get going again you have to heat up. And you can't do that instantaneously. Under most circumstances that Rickover and the S5W designers forsaw, they probably figured that the time savings from not having to heat up the plant coupled with the reduced thermal stresses outweighed the benefit of shaving a few minutes off recovery time by leaving the steam stops open. Sonlee (talk) 23:05, 4 June 2010 (UTC)

1.7MB Animated .gif file

I think having an image that size on the page is a usability issue. It slows rendering and can freeze browsers. It's a very nice illustration of what happened, but I'm not sure it's worth the trouble. Maybe someone with more technical skill than I have could make the file smaller? If not, and if nobody comes up with a compelling reason to keep the file I might edit it out in a few days. 24.69.98.46 (talk) 06:38, 6 July 2008 (UTC)

What are you talking about? The animation sequence is beautiful, and we all should be honored that someone took time out of their day to make such an animation sequence that graphically explains the events. If you can point me to evidence of how it hinders usability, then maybe we can link to the graphic externally instead of actually showing the graphic on the thresher page, but I have an old computer, and it works fine for me. Does anyone else have any issues with it? Azoreg (talk) 00:27, 12 July 2008 (UTC)

It presumably took a fair amount of effort, and I doubt anyone is prepared to remove it, but it looks amateurish, and it has issues. The animation loops, but there's no indication of when it is supposed to start and end; there's no clear timeline throughout the video to explain the chronology - it needs a time clock in the corner (the text-only chronology is a lot easier to understand). There is some text to explain the failure of the vales, but the rest of the action is not narrated, which gives the impression that the frozen valves were the only event that took place - the video doesn't even explain that the reactor fails, or why (perhaps we're supposed to intuit this from the stopped props). Did the submarine really drop like a stone, as portrayed in the video? I understand the desire not to offend people, but it needs to show the submarine imploding, if only with abstract graphics. -Ashley Pomeroy (talk) 20:22, 14 March 2009 (UTC)

This article requires redirects to

This article cannot be reached by typing "Tresher" nor "USS Tresher" in the search bar. Could someone make approbiate redirects? I lack the necessary user level. thestor (talk) 18:45, 21 September 2008 (UTC)

Perhaps if you spelled it correctly. THRESHER not TRESHER —Preceding unsigned comment added by 24.254.242.115 (talk) 03:14, 27 November 2008 (UTC)

Compressed air pressure ?

The "tubes obstructed with ice" version always left me with a doubt "how the hiss was possible then ?". One of Russian article tells that investigation committee figured out, that compression air pressure was someday calculated for diesel submarines, and was not updated when nuclear submarines been designed for greater depths, hence the greater water pressure. The implication was that after power loss, either air pressure or tubes walls were not enough to counter external water pressure and lacking active powered equipment they just could not blow the water out. This article, to me, lacks the info about committee findings, versions and arguments against them. Of particular interest could be, what was the air pressure kept at submarine and how it compares to water pressure in the tanks. 79.111.218.128 (talk) 18:45, 22 September 2011 (UTC)

Further Reading Addition

I've found a book compiled by the U.S. Navy in memorial to the Thresher and her crew. While this book contains little information on the sinking of the Thresher, I believe that it may be of interest to add it to a "Further Reading" section. It contains bios on all crew members, a copy of the eulogy shared at the memorial service, and written condolances from various Navy officers and dignitaries.

U.S. Atlantic Fleet. Staff , Deputy Commander Submarine Force. (1964) United States Ship Thresher (SSN 593): In memoriam April 10, 1963. U.S. Navy Atlantic Fleet. No Available ISBN.

Ethan McHenry (talk) 04:13, 3 February 2012 (UTC)