USS Thresher (SSN-593)

The second USS Thresher (SSN-593) was the lead boat of her class of nuclear-powered attack submarines in the United States Navy. She was the U.S. Navy's second submarine to be named after the thresher shark.

USS Thresher (SSN-593) underway, 30 April 1961
United States
Name: Thresher
Ordered: 15 January 1958
Builder: Portsmouth Naval Shipyard
Laid down: 28 May 1958
Launched: 9 July 1960
Commissioned: 3 August 1961
Motto: Vis Tacita (Silent Strength)
Fate: Lost with all hands during deep diving tests, 10 April 1963; 129 died.
General characteristics
Class and type: Thresher-class submarine
Displacement: 3,540 short tons (3,210 t) light, 3,770 short tons (3,420 t) submerged
Length: 279 ft (85 m)
Beam: 32 ft (9.8 m)
Draft: 26 ft (7.9 m)
Propulsion: 1 Westinghouse S5W PWR, Westinghouse Geared Turbines 15,000 shp (11 MW)
Speed: 33 knots (61 km/h; 38 mph)
Complement: 16 officers, 96 men
Armament: 4 × 21 in (530 mm) torpedo tubes amidships

On 10 April 1963, Thresher sank during deep-diving tests about 220 miles (350 km) east of Boston, Massachusetts, killing all 129 crew and shipyard personnel aboard in the deadliest submarine disaster ever.[1][2] Her loss was a watershed for the U.S. Navy, leading to the implementation of a rigorous submarine safety program known as SUBSAFE. The first nuclear submarine lost at sea, Thresher was also the first of only two submarines that killed more than 100 people aboard; the other was the Russian Kursk, which sank with 118 aboard in 2000.

Significance of design and loss

Created to find and destroy Soviet submarines, Thresher was the fastest (matching the smaller, contemporary Skipjack class) and quietest submarine of the day. She also had the most advanced weapons system, with passive and active sonar, that could detect vessels at unprecedented range, and launchers for the U.S. Navy's newest anti-submarine missile, the SUBROC. Shortly after her loss, the Commander of Submarine Force Atlantic wrote in the March 1964 issue of the U.S. Naval Institute's monthly journal Proceedings that "the Navy had depended upon this performance to the extent that it had asked for and received authority to build 14 of these ships, as well as an additional 11 submarines with very much the same characteristics. This was the first time since World War II that we had considered our design sufficiently advanced to embark upon construction of a large class of general-purpose attack submarines."

Following Navy tradition, this class of subs was originally named Thresher after the lead boat. When Thresher was struck from the Naval Vessel Register on 16 April 1963, the class name was changed to that of the second boat, Permit, and Thresher is now officially referred to as a Permit-class submarine. Having been "lost at sea", Thresher was not decommissioned by the U.S. Navy and remains on "Eternal Patrol".

Early career

The contract to build Thresher was awarded to Portsmouth Naval Shipyard on 15 January 1958, and her keel was laid on 28 May 1958. She was launched on 9 July 1960, was sponsored by Mrs. Mary B. Warder[2] (wife of World War II skipper Frederick B. Warder), and was commissioned on 3 August 1961, Commander Dean L. Axene commanding.

Thresher conducted lengthy sea trials in the western Atlantic and Caribbean Sea areas in 1961–1962. These tests allowed a thorough evaluation of her many new and complex technological features and weapons. She took part in Nuclear Submarine Exercise (NUSUBEX) 3–61 off the northeastern coast of the United States from 18–24 September 1961.

On 18 October 1961, Thresher, in company with the diesel-electric submarine Cavalla, headed south on a 3-week test and training cruise to San Juan, Puerto Rico, arriving 2 November. Following customary procedure while in port, her reactor was shut down. Since no shore power connection was available in San Juan, the ship's backup diesel generator was used to carry the "hotel" electrical loads. Several hours later, the backup generator broke down and the electrical load was transferred to the ship's battery. As most of the battery power was needed to keep vital systems operating and to restart the reactor, lighting and air conditioning were shut down. Without air conditioning, temperature and humidity in the submarine rose, reaching 60 °C (140 °F) after about 10 hours. The crew attempted to repair the diesel generator (four men would receive Navy commendation medals for their work that night). After it became apparent that the generator could not be fixed before the battery was depleted, the crew tried to restart the reactor, but the remaining battery charge was insufficient. The captain, returning to the ship from a shore function, arrived just after the battery ran down. The crew eventually borrowed cables from another ship in the harbor and connected them to the adjacent Cavalla, which started her diesels and provided enough power to allow Thresher to restart her reactor.[3]

Thresher conducted further trials and fired test torpedoes before returning to Portsmouth on 29 November 1961. The boat remained in port through the end of the year, and spent the first two months of 1962 evaluating her sonar and SUBROC systems. In March, she participated in NUSUBEX 2–62 (an exercise designed to improve the tactical capabilities of nuclear submarines) and in anti-submarine warfare training with Task Group ALPHA.

Off Charleston, South Carolina, Thresher undertook operations supporting development of the SUBROC anti-submarine missile. She returned briefly to New England waters, after which she proceeded to Florida for more SUBROC tests. While moored at Port Canaveral, Florida, the submarine was accidentally struck by a tug, which damaged one of her ballast tanks. After repairs at Groton, Connecticut, by the Electric Boat Company, Thresher went south for more tests and trials off Key West, Florida, then returned northward. The submarine entered Portsmouth Shipyard on 16 July 1962 to begin a scheduled 6-month post-shakedown availability to examine systems and make repairs and corrections as necessary. As is typical with a first-of-class boat, the work took longer than expected, lasting nearly 9 months. The ship was finally recertified and undocked on 8 April 1963.[4]


On 9 April 1963, Thresher, commanded by Lieutenant Commander John Wesley Harvey, got underway from Portsmouth at 08:00 and met with the submarine rescue ship Skylark at 11:00 to begin her initial post-overhaul dive trials, in an area some 190 nmi (220 mi; 350 km) east of Cape Cod, Massachusetts. That afternoon Thresher conducted an initial trim dive test, surfaced, and then performed a second dive to half of test depth. She remained submerged overnight and re-established underwater communications with Skylark at 06:30 on 10 April to commence deep-dive trials. Following standard practice, Thresher slowly dove deeper as she traveled in circles under Skylark – to remain within communications distance – pausing every additional 100 ft (30 m) of depth to check the integrity of all systems. As Thresher neared her test depth, Skylark received garbled communications over underwater telephone indicating " ...  minor difficulties, have positive up-angle, attempting to blow",[5][6][7] and then a final even more garbled message that included the number "900".[8] When Skylark received no further communication, surface observers gradually realized Thresher had sunk.

By midafternoon, 15 Navy ships were en route to the search area. At 18:30, the Commander, Submarine Force Atlantic, sent word to Portsmouth Naval Shipyard to begin notifying next-of-kin – starting with Commander Harvey's wife, Irene Harvey – that Thresher was missing.

By morning on 11 April, all hope of finding Thresher was abandoned, and at 10:30, the Chief of Naval Operations Admiral George W. Anderson Jr., went before the press corps at the Pentagon to announce that the submarine was lost with all hands. President John F. Kennedy ordered all flags to be flown at half staff on 12–15 April in honor of the 129 lost submariners and shipyard personnel.[9]

Search and recovery

The Navy quickly mounted an extensive underwater search using the oceanographic ship Mizar and other ships; they soon found shattered remains of Thresher's hull on the sea floor, approximately 8,400 feet (2,600 m) below the surface, in six major sections.[10] Most of the debris had spread over an area of about 134,000 square metres (160,000 sq yd). The bathyscaphe Trieste—then in San Diego—was alerted on 11 April and brought through the Panama Canal to Boston. Trieste was deployed for two series of dives on the debris field; the first taking place from 24 to 30 June, the second from late August until early September.

It found and photographed major sections of Thresher, including the sail, sonar dome, bow section, engineering spaces section, operations spaces section, and the stern planes. One aspect of the search conducted that summer by Mizar involved the use of highly sensitive proton magnetometers furnished by the Instrument Division of Varian Associates in Palo Alto, and shipped aboard Mizar before her departure from Suitland, Maryland. The magnetometers were used in conjunction with underwater video cameras and suspended on the same electrical line used to tow the video cameras themselves.[11]

Trieste's successor, Trieste II, incorporated parts of the original bathyscaphe and was completed in early 1964. The bathyscaphe was placed on board USNS Private Francis X. McGraw and also shipped—via the Panama Canal—to Boston. Trieste II was commanded by Lieutenant John B. Mooney Jr., with co-pilot Lieutenant John H. Howland and Captain Frank Andrews in an operation that recovered bits of wreckage in September 1964. The groundbreaking deep submergence operations helped in the design and construction of other deep-diving submersibles which could be used in rescuing crews and recovering objects from submarines in distress below levels reachable by conventional methods.


Deep-sea photography, recovered artifacts, and an evaluation of her design and operational history permitted a Court of Inquiry to conclude Thresher had probably suffered the failure of a salt-water piping system joint which relied heavily on silver brazing instead of welding. Earlier tests using ultrasound equipment found potential problems with about 14% of the tested brazed joints,[12] most of which were determined not to pose a risk significant enough to require a repair. High-pressure water spraying from a broken pipe joint may have shorted out one of the many electrical panels, causing a shutdown ("scram") of the reactor, which in turn caused loss of propulsion. The inability to blow the ballast tanks was later attributed to excessive moisture in the submarine's high-pressure air flasks, moisture which froze and plugged the flasks' flowpaths while passing through the valves. This was later simulated in dock-side tests on Thresher's sister sub, Tinosa. During a test to simulate blowing ballast at or near test depth, ice formed on strainers installed in valves; the flow of air lasted only a few seconds.[13] Air dryers were later retrofitted to the high-pressure air compressors, beginning with Tinosa, to permit the emergency blow system to operate properly.

Subsequent study of SOSUS (sound surveillance system) data from the time of the incident has given rise to doubts of whether flooding preceded the reactor scram, as no impact sounds of the high pressure water in the compartments of the submarine could be detected on instrument recordings from SOSUS at the time. Such flooding would have been a significant sonic event, and no evidence of that can be found in the recorded data.[14]

Submarines typically rely on speed and deck angle (angle of attack) rather than deballasting to surface; they are propelled at an angle towards the surface. Ballast tanks were almost never blown at depth, and doing so could cause the submarine to rocket to the surface out of control. Normal procedure was to drive the submarine to periscope depth, raise the periscope to verify the area was clear, then blow the tanks and surface the submarine.

At the time, reactor-plant operating procedures did not allow for a rapid reactor restart following a scram, or even the ability to use steam remaining in the secondary system to propel the submarine to the surface. After a scram, standard procedure was to isolate the main steam system, cutting off the flow of steam to the turbines providing propulsion and electricity. This was done to prevent an over-rapid cool-down of the reactor. Thresher's reactor control officer, Lieutenant Raymond McCoole, was not at his station in the maneuvering room, or indeed on the boat, during the fatal dive. McCoole was at home caring for his wife who had been injured in a household accident – he had been all but ordered ashore by a sympathetic Commander Harvey. McCoole's trainee, Jim Henry, fresh from nuclear power school, probably followed standard operating procedures and gave the order to isolate the steam system after the scram, even though Thresher was at or slightly below its maximum depth. Once closed, the large steam system isolation valves could not be reopened quickly. Reflecting on the situation in later life, McCoole was sure he would have delayed shutting the valves, thus allowing the boat to "answer bells" and drive itself to the surface, despite the flooding in the engineering spaces. Admiral Rickover later changed the procedure, creating the "Fast Recovery Startup" procedure. The Fast Recovery Startup allows an immediate reactor restart and for steam to be withdrawn from the secondary system in limited quantities for several minutes following a scram.

In a dockside simulation of flooding in the engine room, held before Thresher sailed, it took the watch in charge 20 minutes to isolate a simulated leak in the auxiliary seawater system. At test depth with the reactor shut down, Thresher would not have had 20 minutes to recover. Even after isolating a short-circuit in the reactor controls, it would have taken nearly 10 minutes to restart the plant.

Thresher likely imploded at a depth of 1,300–2,000 ft (400–610 m).

The U.S. Navy has periodically monitored the environmental conditions of the site since the sinking and has reported the results in an annual public report on environmental monitoring for U.S. Naval nuclear-powered craft. These reports provide specifics on the environmental sampling of sediment, water, and marine life which was done to ascertain whether Thresher's nuclear reactor has had a significant effect on the deep ocean environment. The reports also explain the methodology for conducting deep-sea monitoring from both surface vessels and submersibles. The monitoring data confirm that there has been no significant effect on the environment. Nuclear fuel in the submarine remains intact.

Declassified information in December 2018 showed that USNR Commander (Dr.) Robert Ballard, the oceanographer credited with locating the wreck of RMS Titanic, was sent by the Navy on a mission under cover of the search for Titanic to map and collect visual data on Thresher and Scorpion wrecks.[15] Ballard had approached the Navy in 1982 for funding to find Titanic with his new deep-diving robot submersible. The Navy conditionally granted him the funds if the submarine wrecks were surveyed before Titanic. Ballard's robotic survey showed that the depth Thresher had sunk caused implosion and total destruction; the only recoverable piece was a foot of marled pipe.[16] His 1985 search for Scorpion revealed a large debris field "as though it had been put through a shredding machine." His obligation to inspect the wrecks completed, and the radioactive threat from both was established as small, Ballard then searched for Titanic. Financial limitations gave him 12 days to search and the 'debris-field search technique' he had used for the two submarines was applied to locate Titanic.[17]

Disaster sequence of 10 April 1963 (includes unproven hypotheses)

Time line of the Thresher disaster[18]
07:47Thresher begins its descent to the test depth of 1,000 ft (300 m).
07:52Thresher levels off at 400 ft (120 m), contacts the surface, and the crew inspects the ship for leaks. None are found.
08:09Commander Harvey reports reaching half the test depth.
08:25Thresher reaches 1,000 ft (300 m).
09:02Thresher is cruising at just a few knots (submarines normally move slowly and cautiously at great depths, lest a sudden jam of the diving planes send the ship below test depth in a matter of seconds.) The boat is descending in slow circles, and announces to Skylark she is turning to "Corpen [course] 090." At this point, transmission quality from Thresher begins to noticeably degrade, possibly as a result of thermoclines.
09:09As an unproven hypothesis that is disputed by acoustic data, the Navy's official investigation stated the likelihood of a brazed pipe-joint rupturing in the engine room. The crew would have attempted to stop the leak; at the same time, the engine room would be filling with a cloud of mist. Under the circumstances, Commander Harvey's likely decision would have been to order full speed, full rise on the fairwater planes, and blowing main ballast in order to surface. The pressurized air rapidly expanding in the pipes cools down, condensing moisture and depositing it on intended-as temporary strainers installed in the system to protect the moving parts of the valves during new-construction (should have been removed prior to sea trials)[19]; in only a few seconds the moisture freezes, clogging the strainers and blocking the air flow, halting the effort to blow ballast. Water leaking from the broken pipe most likely causes short circuits leading to an automatic shutdown of the ship's reactor, causing a loss of propulsion. The logical action at this point would have been for Harvey to order propulsion shifted to a battery-powered backup system. As soon as the flooding was contained, the engine room crew would have begun to restart the reactor, an operation that would be expected to take at least 7 minutes.
09:12Skylark pages Thresher on the underwater telephone: "Gertrude underwater telephone check, K [over]." With no immediate response (although Skylark is still unaware of the conditions aboard Thresher), the signal "K" is repeated twice.
09:13Harvey reports status via underwater telephone. The transmission is garbled, though some words are recognizable: "[We are] experiencing minor difficulty, have positive up-angle, attempting to blow." The submarine, as a hypothesis, growing heavier from water flooding the engine room, continues its descent, probably tail-first. Another attempt to empty the ballast tanks is performed, again failing due to the formation of ice. Officers on Skylark could hear the hiss of compressed air over the loudspeaker at this point.
09:14Skylark acknowledges with a brisk, "Roger, out," awaiting further updates from the SSN. A follow-up message, "No contacts in area," is sent to reassure Thresher she can surface quickly, without fear of collision, if required.
09:15Skylark queries Thresher about her intentions: "My course 270 degrees. Interrogative range and bearing from you." There is no response, and Skylark's captain, Lieutenant Commander Hecker, sends his own Gertrude underwater telephone message to the submarine, "Are you in control?"
09:16Skylark picks up a garbled transmission from Thresher, transcribed in the ship's log as "900 N." (The meaning of this message is unclear, and was not discussed at the inquiry; it may have indicated the submarine's depth and course, or it may have referred to a navy "event number" (1000 indicating loss of submarine), with the "N" signifying a negative response to the query from Skylark, "Are you in control?")
09:17A second transmission is received, with the partially recognizable phrase "exceeding test depth ... " The (hypothetical) leak from the broken pipe grows with increased pressure.
09:18Skylark detects a high-energy, low-frequency noise, characteristic of an implosion.
09:20Skylark continues to page Thresher, repeatedly calling for a radio check, a smoke bomb, or some other indication of the boat's condition.
11:04Skylark attempts to transmit a message to COMSUBLANT (Commander, Submarines, Atlantic Fleet): "Unable to communicate with Thresher since 0917R. Have been calling by UQC voice and CW, QHB, CW every minute. Explosive signals every 10 minutes with no success. Last transmission received was garbled. Indicated Thresher was approaching test depth ... Conducting expanding search." Radio problems meant that COMSUBLANT did not receive and respond to this message until 12:45. Hecker initiated "Event SUBMISS [loss of a submarine]" procedures at 11:21, and continued to repeatedly hail Thresher until after 17:00.

During the 1963 inquiry, Admiral Hyman Rickover stated:

I believe the loss of the Thresher should not be viewed solely as the result of failure of a specific braze, weld, system or component, but rather should be considered a consequence of the philosophy of design, construction and inspection that has been permitted in our naval shipbuilding programs. I think it is important that we re-evaluate our present practices where, in the desire to make advancements, we may have forsaken the fundamentals of good engineering.[20]

Alternative theory of the sinking: electrical failure

On 8 April 2013, Bruce Rule, an acoustic data expert, published his own analysis of the data collected by USS Skylark and Atlantic SOSUS arrays in a paper[21] in the Navy Times.[22][23] Rule based his analysis on SOSUS data that was highly classified in 1963 and was not discussed in open session of the Court of Inquiry and was not revealed at the congressional hearings.[23] A retired Navy captain and former commanding officer of the same class of submarine as Thresher, citing Rule's findings, has called for the U.S. government to declassify the data associated with the boat's sinking, and presented an alternative disaster sequence based upon the acoustic data.[24][25]

Rule concluded that the primary cause of the sinking was a failure of the electrical bus that powered the main coolant pumps. According to Rule, SOSUS data indicates that after two minutes of electrical instability, the bus failed at 9:11 a.m., causing the main coolant pumps to trip off. This caused an immediate reactor scram, resulting in a loss of propulsion. Thresher could not be deballasted because ice had formed in the high-pressure air pipes, and so she sank. Rule's analysis holds that flooding (whether from a silver brazed joint or anywhere else) played no role in the reactor scram or the sinking, and that Thresher was intact until she imploded. In addition to the SOSUS data that does not record any sound of flooding, the crew of Skylark did not report hearing any noise that sounded like flooding, and Skylark was able to communicate with Thresher, despite the fact that, at test depth, even a small leak would have produced a deafening roar. Additionally, the previous commander of Thresher testified that he would not have described flooding, even from a small-diameter pipe, as a "minor problem".[23]

Rule interprets the communication "900" from Thresher at 9:17 a.m. as a reference to test depth, signifying that Thresher was 900 feet (270 m) below her test depth of 1,300 feet (400 m), or 2,200 feet (670 m) below sea level. According to Rule the SOSUS data indicates an implosion of Thresher at 09:18:24, at a depth of 2,400 feet (730 m), 400 feet (120 m) below her predicted collapse depth. The implosion took 0.1 seconds, too fast for the human nervous system to perceive.[23]

SUBSAFE legacy

When the Court of Inquiry delivered its final report, it recommended that the Navy implement a more rigorous program of design review and safety inspections during construction. That program, launched in December 1963, was known as SUBSAFE. From 1915 to 1963, the U.S. Navy lost a total of 16 submarines to non-combat accidents. Since the inception of SUBSAFE only one submarine has suffered a similar fate, and that was USS Scorpion, which sank in 1968 for reasons still undetermined. Scorpion was not SUBSAFE certified.[26]



  • The chapel at Portsmouth Navy Yard, where the submarine was built, was renamed Thresher Memorial Chapel.[27]
  • In Portsmouth, New Hampshire, there is a stone memorial with a plaque honoring all who were lost on Thresher. It is outside the Albacore museum.[28]
  • Just outside the main gate of the Naval Weapons Station, Seal Beach, California, a Thresher-Scorpion Memorial honors the crews of the two submarines.[29]
  • In Eureka, Missouri, there is a marble stone at the post office on Thresher Drive honoring the "officers and crew of the USS Thresher, lost 10 April 1963."[30]
  • Salisbury, Massachusetts, named Robert E. Steinel Memorial Park in honor of Thresher crewman and Salisbury resident Sonarman First Class Robert Edwin Steinel.[31]
  • In Nutley, New Jersey, there is a monument to Thresher crewmember Pervis Robison, Jr.[32]
  • In Denville, New Jersey, there is a monument to Thresher crewmember Robert D. Kearney at the Gardner Field recreation area.[33]
  • Thresher Avenue, named for the submarine, serves a residential area in Naval Base Kitsap in Washington state.[34]
  • A 129-foot (39 m) flagpole at Kittery Memorial Circle in the town of Kittery, Maine, was dedicated on 7 April 2013, the 50th anniversary of the loss of Thresher, to honor the 129 lost souls.[35]
  • There is also a Thresher monument in Memorial Park next to the Kittery Town Hall.[36]
  • There is a memorial monument to the submariners lost in the Thresher and Scorpion located on Point Pleasant Road in Mount Pleasant, South Carolina.[37]
  • Naval Submarine Base New London in Groton, Connecticut, named an enlisted barracks "Thresher Hall" after the submarine,[38] and mounted a plaque in its lobby displaying the names of the crew members and contractors that were lost.
  • A joint resolution was introduced during the 107th United States Congress in 2001 calling for the erection of a memorial in Arlington National Cemetery.[39] The formal commemorative monument approval process for Arlington, which began in 2012, received final approval in January 2019.[40][41] The memorial was approved on January 28, 2019, by the Secretary of the Army, Mark Esper.[42] While a few crew members already had memorials at Arlington, this became the first tribute there to the boat's entire crew and her other passengers.[41][43] The memorial was dedicated on September 26, 2019.[44][45]


See also


  1. Duddu, Praveen (6 March 2014). "Peril in the depths – the world's worst submarine disasters". Retrieved 7 August 2018.
  2. Polmar, Norman. The Death of the USS Thresher: The Story Behind History's Deadliest Submarine Disaster. ISBN 978-1592283927.
  3. Polmar, pp. 13–17
  4. "USS Thresher", article by Vice Admiral E.W. Grenfell, U.S. Naval Institute Proceedings, March 1964; accessed 6 April 2013.
  5. "COMSUBPAC Web site, Submarines Lost or Damaged before and after World War II". Archived from the original on 29 January 2006. Retrieved 2 February 2006.
  6. "U.S. Gov Info / Resources, US Navy's Submarine Rescue Team". Retrieved 2 February 2006.
  7. "NOVA Web site, transcript of "Submarines, Secrets, and Spies"". Retrieved 2 February 2006.
  8. Thresher (SSN 593) Loss & Inquiry,
  9. John F. Kennedy (12 April 1963). "Executive Order 11104 – U.S.S. Thresher". Executive Order.
  10. Brand, V (1977). "Submersibles – Manned and Unmanned". South Pacific Underwater Medicine Society Journal. 7 (3). ISSN 0813-1988. OCLC 16986801. Retrieved 10 July 2008.
  11. "Loss of USS Thresher".
  12. 50 Years of Steely Purpose-USS Thresher Remembered Archived 26 June 2013 at 10 April 2013.
  13. Thresher (SSN-593) Loss & Inquiry Archived 31 October 2013 at the Wayback Machine.
  14. "Information and Security Issues Associated with the Loss of the USS Thresher".
  15. The Great Explorer 60 Minutes; aired 29 November 2009
  16. Lost Subs: Disaster at Sea. Tim Kelly, Executive Producer. DVD. National Geographic, 2002.
  17. : Titanic search was cover for secret Cold War subs mission The Times, 24 May 2008
  18. Bentley, John. The Thresher Disaster, New York: Doubleday, 1975, pp. 157–165
  20. "Vanderbilt ties to 'worst submarine tragedy' 50 years ago". School of Engineering, Vanderbilt University. 2013. Retrieved 23 April 2013.
  21. "What Sank The Thresher", Bruce Rule, 10 April 2013
  22. "50 years later, a look at what really sank the Thresher", Bruce Rule and Norman Polmar, 4 April 2013 (Navy Times link)
  23. "What Sank The Thresher", Bruce Rule and Norman Polmar, 8 April 2013
  26. "USS Thresher Left Legacy of Safety for Submarines". SeaCoast online. 24 March 2013.
  27. Winslow III, Richard E. (1985). Portsmouth-Built: Submarines of the Portsmouth Naval Shipyard. Portsmouth Marine Society. p. 161. ISBN 091581904X.
  28. "Wreck of USS Thresher (SSN-593) – Portsmouth, NH – Disaster Memorials on". Retrieved 1 June 2010.
  29. "ThresherScorpionMemorial". Archived from the original on 18 May 2010. Retrieved 1 June 2010.
  30. Park Board Minutes 04-10-2007 (pdf file) Archived 26 June 2008 at the Wayback Machine
  31. Kerr, D. Allan (20 January 2013). "Thresher victim, a young father, remembered". Retrieved 30 January 2019.
  32. "Nutley NJ USS Thresher Memorial". Flickr. Retrieved 13 August 2016.
  33. "Robert D. Kearney Memorial marker". GoogleMaps. Retrieved 21 May 2017.
  34. "Thresher Ave". Google Maps. Retrieved 5 April 2018.
  35. "Thresher Flagpole". Retrieved 30 January 2019.
  36. "Memorial Park". Retrieved 5 April 2018.
  37. " THE HISTORICAL MARKER DATABASE". Retrieved 30 May 2019.
  38. "Bachelor Housing". Retrieved 30 January 2019.
  39. Robert Patterson, Michael. "USS Thresher Disaster". Retrieved 1 June 2010.
  40. "USS Thresher memorial to be built at Arlington National Cemetery". WMTW. 29 January 2019.
  41. Barndollar, Hadley (29 January 2019). "USS Thresher memorial approved for Arlington National". Foster's Daily Democrat. Dover, New Hampshire. Retrieved 30 January 2019.
  43. Grady, John (31 January 2019). "Army Set to Approve USS Thresher Memorial at Arlington National Cemetery". USNI News.
  44. Ruane, Michael E. (26 September 2019). "The nuclear submarine Thresher was said to be America's best. Then tragedy struck". The Washington Post. Washington, D.C. Retrieved 26 September 2019.
  45. Spiner, Trent (26 September 2019). "'Tears in my eyes': USS Thresher memorial dedicated". Foster's Daily Democrat. Dover, New Hampshire. Retrieved 28 September 2019.
  46. "Brief Timeline of the Dundee Township Park District" (PDF). Retrieved 30 January 2019.
  47. "Executive Order 11104". 15 November 2005. Retrieved 22 October 2018.
  48. Spilman, Rick (14 April 2013). "Four Ballads of the USS Thresher". Retrieved 30 January 2019.
  49. Powers, Ann (17 August 2014). "First Listen: Shovels & Rope, 'Swimmin' Time'". Retrieved 9 August 2019.


Further reading

  • Joint Committee on Atomic Energy (United States Congress) (1965). Loss of the U.S.S. "Thresher": Hearings, Eighty-eighth Congress, first and second sessions. Govt. Print. Off. Retrieved 5 April 2013.
  • U.S. Atlantic Fleet. Staff, Deputy Commander Submarine Force. (1964) United States Ship Thresher (SSN 593): In memoriam 10 April 1963. U.S. Navy Atlantic Fleet. No Available ISBN.
  • Thresher's ship number 593 is interesting as a "good" prime number, as discussed at 593.

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