Named for the Thresher Shark and the first of
its class, The USS Thresher SS-593 was laid down at Portsmouth Naval Shipyard in Kittery,
Maine... this vessel would pioneer a new, more modernized fleet of nuclear powered
attack submarines in the US Navy. Being the first of its class
meant, as originally planned, those that followed, would have
been, "Thresher Class" Submarines. Thresher SS-593 would actually be
the second Submarine to take the name after the first Thresher,
SS-200, a Diesel submarine that served successfully throughout World
War 2 and was decommisioned in 1945. Launched in July 1960, the
Nuclear Powered Thresher would, according the the US Navy's Judge Advocate
General Court of Inquiry or JAG report; "...revolutionize advances in sonar equipment, the ability to resist shock and would
operate with reduced noise radiation." According to the US Naval Institute; the thresher
performed initial sea trials in April of 1961. This new class of Sub would
combine the roles of "Attack" and "Hunter-Killer"... to combat the
threat of their Soviet counterparts. With what was, at the time, the
most advanced Sonar in the bow, equipped with the latest anti-ship
and anti-submarine torpedoes... The Thresher would measure in at: 278 feet 6 inches Long
31 feet 8 inches Wide It's reported that the thresher was expected to
dive to some 1300 feet or roughly a quarter mile deep, purportedly, the deepest of the time period.
It Had a reactor power plant that gave the sub unlimited range and a top
of speed more than 20 knots. Under normal operations, the crew consisted
of 16 officers and 96 enlisted men. At the official commissioning ceremonies in
Portsmouth Shipyard, August 3rd 1961 Vice Admiral Harold T Deutermann declared: "Thresher is not
just another ship. Thresher is totally different!" After the commission, the Thresher
underwent further sea trials and excercises off the Atlantic Coast and
according to the US Naval Institue; "...sailing as far south as Puerto Rico. While
in port in San Juan, the crew encountered problems with her diesel generator and then had
difficulty in restarting her nuclear reactor. Shock tests followed, with the Thresher subjected
to a greater intentional pounding than any other submarine in Navy history. She stood up remarkably
well, with Commander Axene stating: 'There was no question that the Thresher suffered damage. .
. . 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.” After more extensive testing and trials,
the Thresher would return to Portsmouth Yard in July of 1962. They would host what
was called a "Happy Cruise" where wives, parents and children were allowed to come
along for a family themed embarkation. The vessel would then return for extensive,
nearly year long scheduled maintenance work. With the crew and vessel essentially laid
up, Commander Axene would also state: “Relations between Thresher and Portsmouth
were always extraordinarily good, at least in my experience.” But he quickly added: It is true that we felt they should have been
more efficient, should done better work at times, and move more quickly, and they should have done
a better job of cleaning up after themselves. I was told by others that relations did
deteriorate toward the end of the Post Shakedown." By April of 1963, after around 9 months in
the shipyard for post shakedown, the Thresher was being prepped to finally depart
Portsmouth and resume sea trials, growing ever closer to being fully operational. The Sea Trials were to take place roughly 250
miles (402 km) east of Cape Cod, Massachusetts. Assigned as the Submarine's escort,
for the trials, was the USS Skylark, a 205 ft Penguin Class Submarine Rescue Ship.
This small escort was fitted with all manner of sonar and communication devices needed
to maintain contact with US Submarines... ...and when performing its intended
duties, the two vessels would make attempts to operate hand in hand, so
to speak. According to the JAG report, the Skylark also carried a rescue
chamber with a Max Depth of 850 ft. The Thresher would get underway on
the morning of Tuesday April 9 bound for their 1st rendezvous with Skylark
roughly 16 miles southeast of Kittery. According to the JAG Report... On board for the trials were; 112 Navy personnel comprised of 96
Enlisted Sailors and 16 officers 17 persons on board working
as civilian contractors to witness the trials from Portsmouth Naval
Shipyard, Raytheon and Sperry Corporation. 129 Souls Aboard The two vessels reached the
coordinates at about 9:49am, established communications and the Thresher
performed a scheduled shallow dive... Completing this first encounter, their 2nd
rendezvous would be roughly 300 miles east, planned for the following morning. Each ship would be proceed independently, with the intention of meeting up again
at the pre-determined coordinates. On its way there, the Thresher
travelled both submerged and surfaced, testing brief dive sequences
and full power propulsion. The Skylark arrived near the coordinates
at 7:45am. This area of the Atlantic was roughly 8,500 feet deep... or
1.6 miles. The sea was calm, visibility was about 10 miles and no other ships
were known to be present in the area at the time. Thresher reported in to Skylark stating they
had the vessel at about 3400 yards away. They were currently communicating via the
underwater telephone system or UQC that the escort ship deploys to a certain depth for listening
and works even with a submarine submerged. The UQC system receives and transmits sound much
like sonar and turns these signals into audible voice transmissions like a phone call... it
can also aid in range finding its source. However, Skylark did not show any contact on
Thresher on their main sonar at this time. The Skylark's sonar said to
have a maximum of 3750 yards. The submarine possibly outside their range.
Regardless, Skylark hadn't plotted Thresher's position... only knew of their presence via
the brief communications back and forth. By 7:47am Thresher reported via phone
they were beginning their deep dive test. This JAG report shows it redacted but
later reports stating the expected test depth would be 1300 feet
deep or roughly a quarter mile. Skylark held position as Thresher
reported intial course and depth changes, but still hadn't plotted the submarine's position. At 9:13am, Skylark received another
transmission from Thresher stating; From the US Naval Institute: “Have positive up angle' implies that the
submarine had recovered from a down angle, possibly caused by a stern plane's jam. The report of “attempting to blow up”
confirms that the MBT blow was ineffective." The MBT Meaning the Main ballast tanks,
"blown" by using high pressure air forced into the water filled tank, forcing the water
out rapidly, creating a buoyant, air filled tank. Typically an emergency surfacing procedure and the process that creates those spectacular shots
of modern Submarines blasting to the surface. It's unclear whether the Thresher meant
this as an emergency blow of some sort, but many experts say this
was a sign of an emergency, despite the seeming lack of urgency
in the verbiage used to describe it. The need to blow the tanks at all, rather
than controlling the vessel's pitch, via forward velocity and dive planes, as would
be standard procedure... suggests the vessel was indeed, in serious trouble already and
had lost propulsion... according to experts. BUT it's possible the Thresher's
command remained confident in the vessel and crew to troubleshoot
themselves out of the situation. Skylark promptly responded to advise them the area was clear and let them know Skylark's
course, bearing and approximate range. Then at 9:15am Skylark
asked "Are you in control?", repeated this and carried out radio checks. One Minute Later, 9:16am and Skylark
heard a garbled transmission; ...only making out the words "...test depth." Which many have since surmised
that the word exceeding is most likely what preceded this. "Exceeding Test Depth" Then just after that; ...only making out the words
"...nine hundred North." Or, an indication they were
also on bearing 90 north. During this time, the Skylark heard 2 disturbances that could have been the
blowing of ballast tanks... But soon after the final transmission
"...Nine Hundred North", at 9:18am, according to the report, a
much clearer high-energy, low frequency disturbance was heard that had
all the characteristics of sudden implosion. Skylark continued attempts to
contact the Thresher, to no avail. By 10:40am they began dropping their
emergency hand grenades in the water. These were used as rudimentary signals in case of
communications failure to convey the message to those listening on the Submarine, that they
need to return to the surface immediately. The Skylark then decided, at 10:45
am to send a message they'd prepared, reporting the loss of contact with Thresher. This message sent to Naval Radio Station
NBL or Station New London, Connecticut. However, there was difficulty in getting the
message through. Skylark shifted to an alternate frequency, with station New London finally
acknowledging at 12:45 am. 2 Hours later... The message as follows; "Unable to communicate with thresher since 0917.
Have been calling by UQC Voice and CW QHB CW every minute. Explosive signals every 10 mins with no
success. (meaning their hand grenade signals) Last transmission received was garbled.
Indicated Thresher was approaching test depth. My present position 41-43N 64-57W
conducting expanding search." The JAG Report pointing out that this message
lacked some critical information that, by the report's wording, suggests *should*
have been sent in such a situation. While Skylark began their
expanding search pattern, using their QHB-A Sonar System as their
principle means of underwater detection... The initial parties to join the
Skylark on scene would be... The rescue and salvage ship USS Recovery
(ARS-43) and a number of patrol aircraft. It's clear from the reports that the USS
Recovery arrived that same afternoon. At 5:30pm, the Recovery spotted an oil slick
1,000 feet in diameter of bluish color, about 7 miles southeast of Skylark's position. The destroyer USS Blandy
(DD-943) then joined later, having gotten underway from Newport
Rhode Island at about 6:30pm. And the Submarine USS Seawolf (SSN-575), arrived on scene at what looks like 5:30am
the following morning. The JAG report states; "Command of the search force passed
from Commanding Officer, Skylark, to Commander Submarine Development Group
Two at about 5:30am, April 11th 1963..." "While operating as a unit of the search
force, the USS Seawolf recorded possible electronic emissions and underwater
noises. None of the signals which Seawolf received equated with anything that
could have been originated by human beings." ...and that; "Naval Units
and personnel were assisted by civilian scientists and research ships." The initial Search and Rescue efforts,
would never produce any positive results. Now, Even if they had located the Thresher
right away, the potential for any sort of deep sea rescue, especially in the
time period was extremely limited. The USS Skylark, with its wide array of
relevant communications and detection equipment, was still completely powerless to
physically render assistance at technically anywhere below 850 feet deep, the limits
of its onboard submersible rescue chamber. In addition, carrying out rescue missions
of submarines beneath the surface is an extremely precarious undertaking,
even in the most ideal conditions... The typical rescue chamber, for example, carried on board a vessel like the
Skylark had very limited capabilities. The stricken vessel must not be in
waters with a strong current and it must be upright as the chamber cannot attach
at extreme angles and again, being limited to 850 feet... in this situation meant even the
planned test depth was too deep for rescue. This exposed (according to the Navy
themselves), yet another critical limitation in their deep sea capabilities
which we will cover briefly in this video. Initially found in or near that original Oil Slick
the night of the sinking, picked up by the USS Recovery & Skylark, were small bits of debris,
which revealed a much larger, grim truth... Something catastrophic must have
happened to the USS Thresher. Later lab tested and confirmed
to be from the Thresher, which could have only reached the
surface if the vessel had broke up... From the Glasgow Herald; -A Pair of Work Gloves used only in the
Nuclear Reactor Section of the Thresher -Bits of Cork of a Special
Design for interior insulation. -Bits of Plastics used to protect reactors
from leaking radiation throughout the ship These pieces amongst many other
very small plastics and styrofoam. -With no sign of the vessel during what could
only *potentially* be considered a window of search and rescue opportunity.
-Due to the debris and oil slick -Due to other detailed findings
we'll cover here shortly, According to the JAG Report; "Thresher was lost at sea with all on
board at about 9:18am on April 10, 1963." The JAG, Court of Inquiry to get
to the bottom of this incident was put into action the same day
of the sinking, April 10, 1963. This official report ruled
out Sabotage & Enemy Action. And from what I see cited as primary
evidence of the instant implosion & breakup, aside from the communications and sounds as
the incident unfolded ...is the wreckage, which, without a doubt, appears
to be catastrophic breakup. The Search for the Thresher, worthy of a
video on its own... evolved from quote; "No Real Search Ogranization, No Search
Technique, nor specific operating procedures..." ...starting on the day of the incident, to
a massive operation of military acronyms, three separate major groups, the Sea
Farers, The On Shore Support group who could acquire the needed tech and vessels
for searching so deep and the analysis group. Woods Hole Oceanographic Institution
The Office of Naval research The Submarine Development Group from New London
The Naval Oceanographic Office Using, Fathometers (FATHOM Meters), Deep Towed Geiger Counters, Side Looking
Echo Sounders and in the final phases, deep sea capable tv or still cameras either
towed or mounted to a capable Bathyscaphe. But finding a Bathyscaphe capable of traversing the near Abyssal depths in the area
Thresher was lost proved difficult. According to the US Naval Institute; "-No one was quite sure whether or not the Thresher would return an echo
from the search Fathometer -No one was quite sure that the navigation in
the disaster area could be carried out accurately enough to insure 100 per cent Fathometer coverage
of the ocean bottom with a minimum of duplication -No one possessed any real operational experience
at towing a magnetometer, Geiger counter, TV camera or a side-looking, echo sounder 15 to
200 feet off the bottom at depths of 8,400 feet. In fact, the design of the various sensors
was, in April, merely a topic for discussion, or at most in the preliminary “purchase-of-parts” stage in the various oceanographic
laboratories throughout the country." The Bathyscaphe Trieste, a storied
vessel itself... played a major role toward the end in getting
some of the clearest shots once the Thresher was located in its
final resting place 8,400 feet deep. The scene described by the
Officer in Charge of Trieste as... Like "A Huge Automobile Junk Yard with big
pieces of heavy metal all over the place." It's even been reported, that researchers sank
derelict cars and even a decommissioned diesel submarine to gauge drift and currents
in an effort to locate the Thresher. This process of searching and documenting took
over a year and still wasn't fully complete by summer 1964 but the picture was definitive. The
Thresher had experienced catastrophic breakup. At this depth, the Thresher was found toward the
bottom of the Bathypelagic (Bath - uh - Puh Laa Jik) zone, nearing the Abyssal zone. Why it was
testing in waters so deep I have no idea but with no "safety net" so to speak, below their test
depth, not even near their purported collapse depth... there was very little room for error
...and in a vessel fresh out of Post Shakedown. This, combined with the fact that while US Navy
Submarines do have their maximum dive depths classified to this day, there's still a limit
to what's physically possible based simply on the technology we mortals have to build with...
even for these venerable submarine manufacturers. Submersibles you see diving several miles
deep or more, they're small for a reason... physical size limits the vessel's ability
to withstand the unimaginable forces it must endure in the deep and it's no secret that
military, nuclear submarines are rather large. Thus more surface area to reinforce. From the US Naval Institute: "The U.S. Navy constructs submarines to withstand
one and one-half times the pressure of their designed test depth. That is a safety factor.
The collapse depth is based on both mathematical calculations and model tests. It thus seemed
reasonable to assume that the collapse depth of the Thresher was approximately 1,950 feet.
The sequence of casualties... (Marine Casualties referred to in this instance as accidents or incidents that can
cause a vessel major issues)
The sequence of casualties suffered by the
Thresher apparently caused a fateful depth increase of some 600 feet—from test depth
to collapse depth—in five agonizing minutes. As she neared collapse depth, the fittings
and pipes would have begun to give way, admitting powerful jets of water that pushed
aside men as they struggled to plug them and shorted out electrical systems, making corrective
action impossible. The additional weight of water thus admitted would have driven the Thresher
still deeper at an ever-increasing speed. The submarine’s hull would groan under the increasing
pressure trying to crush her air-filled interior. There probably were no serious
personnel casualties to that point. But all in the submarine would now
have sensed that they were rushing toward disaster and groped frantically
for some means of escape or survival. The insulating cork that lined the submarine’s
interior would begin to crack and possibly flake off. Pipes would pull apart as the water
pressure began to “pull” the submarine’s hardened steel—like taffy. The hull would then
implode. Complete destruction would occur in 1/20th of a second, too fast to be cognitively
recognized by the men within the submarine. Millions of pounds of water under tremendous
pressure would smash the submarine’s hull, breaking it open, twisting portions,
disintegrating other parts. The theory that water filled the plummeting
Thresher before she could implode is generally discounted because the additional
weight of water would have accelerated the downward rate and caused an implosion
before the hull could fill with water." Now, the Skylark was the ONLY
vessel in the vicinity aside from the Submarine it was assigned to monitor. With experts at the helm of Skylark's sensors, it
would be standard practice to know via distance, intensity and angle which sounds
correspond with what type of source... This is one of the foundations of sonar operation
and listening devices utilized in the world of undersea detection, it's not just hollywood
ping noises and bright green radar screens. This incident though, as many may have
noticed, isn't like those I normally cover. There is an incredible amount of
nuance to both how it happened and the recommendations and industry
changes that came as a result. But there are very thorough reports out
there for those who know where to look. We'll be doing a brief summary in today's
video but I *am* planning a follow up for later to dig into the massive amount of detail
and recommendations found by both; experts and authorities in the time period and then later
unearthed via Freedom of Information Act reports. So keep an eye out for a follow up, or
as I call them my "After Words" episodes ...possibly a livestream but either way,
we'll dig deeper and it'll give me some time to gather my thoughts and pore over
a myriad of documents on what eventually became a rather controversial subject
in the world of military submarines. The Thresher, its crew complement and dedicated
civilian contractors, 129 total souls on board. They led the way to... Firstly, The Subsafe program; At a House Science Committee Meeting in October
2003, US Navy Rear Admiral and Deputy Commander for Ship Design, Integration and
Engineering stated the following; "The loss of THRESHER and her
crew was a devastating event for the submarine community, the Navy and the nation. The Navy immediately restricted
all submarines in depth until an understanding of the circumstances surrounding
the loss of the THRESHER could be gained. "While the exact cause of the THRESHER loss
is not known, from the facts gathered during the investigations, we do know that there
were deficient specifications, deficient shipbuilding practices, deficient maintenance
practices, and deficient operational procedures. Here’s what we think happened: THRESHER had about 3000 silver-brazed piping
joints exposed to full submergence pressure. During her last shipyard maintenance period,
145 of these joints were inspected on a not-to-delay vessel basis using a new
technique called Ultrasonic Testing. Fourteen percent of the joints tested showed
sub-standard joint integrity. Extrapolating these test results to the entire population
of 3000 silver-brazed joints indicates that possibly more than 400 joints on
THRESHER could have been sub-standard. One or more of these joints is believed to have
failed, resulting in flooding in the engine room. The crew was unable to access vital
equipment to stop the flooding. Saltwater spray on electrical
components caused short circuits, reactor shutdown, and loss of propulsion power.
The main ballast tank blow system failed to operate properly at test depth. We believe
that various restrictions in the air system coupled with excessive moisture in the system
led to ice formation in the blow system piping. The resulting blockage caused an inadequate
blow rate. Consequently, the submarine was unable to overcome the increasing weight
of water rushing into the engine room. The loss of THRESHER was the genesis
of the SUBSAFE Program. In June 1963, not quite two months after THRESHER sank,
the SUBSAFE Program was created. The SUBSAFE Certification Criterion was issued December
20th 1963, formally implementing the Program." According the Thresher Memorial dot Org; "The purpose of the SUBSAFE Program
is to provide maximum reasonable assurance of watertight integrity and
recovery capability of a Submarine. A culture of Safety is central to the entire Navy
submarine community. This starts at the designers, and includes builders, operational crews
as well as maintenance organizations. The SUBSAFE Program clearly defines non-negotiable
requirements, requires annual training of personnel and then ensures compliance with reviews
including audits and independent oversight. The annual training requirement includes review
of past failures including the loss of Thresher." In addition, the Deep Submergence
Rescue Vehicle or DSRV Program was also heavily inspired by the loss of the Thresher. According to Naval Undersea Museum dot org; "The sinking of the submarine USS Thresher
(SSN 593) in April 1963 revealed significant limitations in the Navy’s deep-sea capabilities.
The Navy formed the Deep Submergence Systems Project in 1964 to develop a new rescue
vehicle. The project produced two highly capable submersibles, Mystic (DSRV 1) and
Avalon (DSRV 2), that launched in 1970 and 1971. Following extensive sea trials,
they entered full operational status in 1977 and served as the Navy’s primary
submarine rescue system through 2008. The DSRVs could deploy by sea, air, or land
to reach a disabled submarine anywhere in the world within 72 hours. Once on site, a mother
submarine or submarine rescue ship carried the DSRV within range of the distressed submarine.
The DSRV then attached to the submarine’s escape hatch and transferred stranded personnel
back to the support vessel in groups of 24. Although the Navy conducted numerous practice
exercises with the DSRVs, they have never been used for a real rescue operation. No American
submarine has sunk since the DSRV program began." With the loss of the USS Thresher, there would be
no lead ship for the "Thresher Class" namesake. This passed on to the next vessel
launched under the same class, the USS Permit and thus, the
Permit Class forged ahead... Comprised of 13 Submarines that all saw
successful, roughly 30 year life cycles. All of which decommissioned
successfully. And unfortunately, from what I could find, were also then
recycled and none survived as museum ships. One of our favorite familiy activities is visiting
and getting immersed in museum ships. Anyway... The USS Thresher has had many
memorial ceremonies and dedications. Among the many static memorials,
perhaps the most poignant; The Monument in Arlington National
Cemetery being one of the most promiment as it only recently was
dedicated... September 26 2019. And multiple memorials in Kittery, Maine.
The home of Portsmouth Naval Shipyards. In Memoriam... Thanks so much to those who support this channel and an extra special thanks to
our top tier patreon supporters; Alex S
Alex W Andrew M Kenneth P
Nathan F Paul R
P Rush Philip B
Robert G and
Troy H And Don't Forget, Your Safety Matters.
