The Classified Sinking of the Submarine USS Thresher

USS Thresher was the lead submarine of her class of nuclear-powered attack boats in the 1960s. Named after the thresher shark, the US Navy submarine had state-of-the-art features that made it the fastest and quietest U-boat of its day, significantly pushing the boundaries of Cold War technology.

But in April of 1963, the USS Thresher atomic submarine left port to perform a series of test dives off Cape Cod, Massachusetts, and never came back.

When the submarine sank to the bottom of the ocean after a series of bewildering underwater phone calls, the naval community was baffled.

But the Navy classified the report, only releasing scant details about the accident that took 129 lives.

The mystery then lived on for several decades until a brave lawsuit brought the document to the forefront. To this day, we still keep learning about what happened on that fateful morning...

[scottcole]

This video was only partially correct. I was a Navy Nuke Machinist Mate and while I was aboard the USS Texas CGN-39 ( a Nuclear Cruiser) the sinking of the Thresher affected us directly. Actually it affected every single nuclear warship.
First, what actually happened to the Thresher (or at least what the Navy really thought happened to it.)
There was some type of electrical issue, possibly caused by a seawater pipe leak that caused the reactor (Rx) to scram. When the Rx scrammed the main steam stops automatically slammed shut. The main steam stops are huge air close, manual open gate valves about 24" in dia. It took about 300 turns ( about 5 min plus with several of the biggest, most hulking Machinist Mates standing in line to relieve each other as they got tired.) to open one of the stops on my ship. The reason the main steam stops shut automatically was to maintain Rx temp so that when the Rx control rods were pulled the Rx could resume normal operations immediately instead of having to wait for the coolant T-ave to warm up. unfortunately this meant that the 15, 000 shp main engine (Steam turbine) was not available to drive the ship to the surface in an emergency if the Rx had scrammed.
So now the Thesher has no main engine and has negative buoyancy (possibly from the leak). Don't count on the backup electrical motor. It was a joke, not very powerful and not much battery reserve. That leaves only one possible choice for the Captain. Emergency blow the mains! Every submarine has a large bank of high pressure ( about 3000 psi) air tanks. There is a big red covered button in the control room. It is every submariners GOTH (GO To Hell) plan. When all else fails and death is imminent and only when the Captain orders it you hit the Emergency Blow button.
This releases the contents of the tanks into the open bottom buoyancy tanks and hopefully the sub pops to the surface like a cork. Unless of course the compressed air has too much humidity in it. The rapid pressure drop of the air going through the piping to the tanks causes the temp to drop dramatically (This is how air conditioners work) if the cold air has enough humidity in it it will flash freeze and block the pipes. The only thing you can do then is stop the blow and wait for the ice plug to melt. Unfortunately the Thresher di not have that kind of time as they were sinking deeper, closer to crush depth. They did even have the time required for the main steam stops to be reopened. We know what happened next.
How do I know this? Because at some point afterwards when the Navy figured out what really happened they removed the requirement for the main steam stops to automatically shut on a scram. While Captains were instructed to conserve Rx coolant temp if possible they were also told they should run the Rx down to ambient if was an extreme emergency. Once again how do I know this? Because I was a senior qualified Machinist Mate in charge of all the other MMs in the engine room. I was required to know every possible step when dealing with a mechanical emergency. The Navy (actually Hyman Rickover at the time) knew that in order to ensure we met every emergency they had to teach why we did things, not just what to do.
So know you know...

[commanderstraker]

When I served in the N.H. General Court (House of Representatives) my seatmate was a retired engineer from the Portsmouth Naval Shipyard. One of the bennies for the engineers was the chance to go out on short cruises and see how things worked in real life. He was scheduled to ride out on THRESHER that morning, but was bumped by a naval officer who needed to go out to keep his certifications current. When he found out what had happened he went to Mass every morning for over a year.

[SuperOperator]

My father was a welder on it. He worked in Portsmouth for 15 years. He knew many of the crew that perished that day. After the accident he came home and I'd never seen him cry like he did that day. I was only 4 years old at the time.

[Dave-]

Due to the nature of my job I am DSS-SOC and SUBSAFE certified. Every year during my routine SUBSAFE training I have to listen to the recorded sounds of the Threshers bulkheads imploding as a reminder of the importance of the SUBSAFE program, and every year those sounds chill me to the core. "Lest We Forget"

[francispitts]

My friend from high school joined the Navy on the same day I went in to join the Marines. He ended up spending his entire life in subs. He just retired and was at our 40th reunion. He has some very interesting and cool stories. I have a genuine respect for anyone who serves in submarines.

[Dan-ggfk]

I was in the assembly building with my father the day the Thresher was launched. We were just amazed by the event. My father was a civilian contractor at the Portsmouth Naval Shipyard and was scheduled to go on that later test run. His crew leader died in a car accident a week before so they switched teams which meant that my father would stay ashore. He was saved. A tragic loss for those aboard. God bless them all.

[kennethcatlett]

My sub school class (I was the only non rate in a class of nuclear trained 3rd & 2 class petty officers )in the early 1970 ; we were told the 1 1/2" blow piping were increased to 3" blow piping due non crushed blow piping found at the USS Thresher final resting location. They believed these pipes were not crushed due ice forming inside the blow piping. All submarines blow piping was increased to prevent this freezing of moisture condensation in the blow piping system. Getting my SS qualification was an awesome achievement for me. I transfered as AN(SS) to become a Navy Photographers Mate/SS. Later I attempted to get back into Submarines as Quartmaster/SS but was unable and had to go to the surface Navy. Submarines were very interesting and I am proud to have served in the SS service.

[randyterwilliger]

I grew up in New London ct and was in seventh grade when the Thresher went down . There were a few classmates in my school who’s dads were on the sub when it went down . As the safety record for our sub fleet was very good it was quite a shock and as General Dynamics, Electric Boat Division was the primary builder of our underwater fleet and the biggest employer in our area the entire region felt connected to the tragedy .

[christophersnyder]

Along with the USS Scorpion, this was a very tragic incident. On a side note, I remember a Bond film featuring a submarine with the same pennant number as that of the USS Thresher SSN-593.

[jimmoos]

I just watched the video and, from my experience, it is quite accurate from what I remember being on a sister sub in the early 70's. I was a Nuclear Machinist Mate on USS Haddock SSN 621, as was one of other commenters. In 1970 I met the boat in Hawaii and made many local deployments. The training for "ships qualification" and for my rate were rigid and mandatory. We were schooled on the Thresher accident and learned of subsequent operational limits put on subs as a result of the accident. Operating depth was limited and, in an upcoming yard period, several changes and improvements were made to preclude the initial and exacerbating design issues that sunk the boat. At the time, the initiating event was a ruptured "sil-braze' joint that resulted in seawater spraying vital electrical panels -- as shown in the video. This was a nightmare as it affected the reactor and resulted in flooding. After some accident mitigation, the sub was able to use it's electric motor on the shaft to get some propulsion and, i believe, they actually made it to within 200? ft of the surface. Then, it lost the battle and the sub went down for good. Terrible way to go, but somewhat mercifully, it was fast.
By the way, Dr Ballard was assigned to locate some Russian ordinance, not the Thresher, when he found the Titanic.
It's amazing how the recent loss of the commercial sub near the Titanic has churned up lots of discussion and war stories from people who were in the Sub service. I just can't get my grandchildren too excited about it, though.

[tebo]

My dad was on the Nautilus when the Thresher went down. He lost a friends from nuclear power school when that happened. He always told me that he left the Navy after 17 years on subs because the Navy got reckless and careless when it came to both new subs and maintenance on existing ones. This report really supports his claims.

[DavidSmith-sscg]

The US Navy knew what had happened by that afternoon, because the sub's implosion was heard from 2 separate listening arrays, and operators had heard similar noises from implosions in WW2, and they knew what they had heard. When they told the families of the crew their loved ones were missing, they already knew the crew's fate. The implosion crushed them a tenth of a second; they never knew what hit them.
Much later, When Robert Ballard found the Titanic, he used the deep-sea submersible Trieste II to find the debris fields of the wrecks of Thresher and the USS Scorpion. He was able to find these subs remains by working from their last position and finding their wrecks by locating their debris fields. He also detected no radioactive material from them, which put a long-lasting worry to rest. Their reactors and nuclear material was safe. Ballard then used the same method to locate the Titanic - which he did the next summer, by following the debris field.
The US Navy had been lucky to get away with rushing all of those new classes of ships into production so fast, and Admiral Rickover knew it; He insisted that the Navy adopt much more stringent safety precautions and initiated a lot of new policies. Since the Thresher died in such an ugly manner, there have been few incidents like it in almost 60 years.

[kathleennorville]

Living in the Threshers home town, this hit our community very hard in 1963. Thank you for your coverage and great channel and god bless those sailors.

[billylewis]

As a submariner on a Permit Class boat, USS DACE, I can tell you that there are many sea stories on this.

Major pucker factor every time we went to test depth.

[charlesmoore]

Oh, the Thresher, the finest atomic ship
that ever dived for the sea.
Each man on board was a volunteer.
He was there for he chose there to be.

[namespacestd]

I read the Navy was ordered to declassify USS Thresher investigation reports by the court but didn't know what was in those reports. Thanks to this video I finally can imagine how and why Thresher sank. May the crew rest in eternal peace

[johnwilliamson]

I remember when this happened. I was 12 years old. It was on the news. Everyone was praying for there safe return. But, by that time they were all dead it seems. Very very sad.

[chuckellis]

We studied about the Thresher when I attended Basic Enlisted Submarine School in 1984. Safety and attention to detail were hammered into us. On the submarine we did several refits in drydock with a hole cut in the hull. I always thought about the Thresher while we did sea trials afterwards. I also was involved in repairs that included SubSafe systems on the boat, there was a mountain of paperwork and procedure to complete, it was the price being able to return home so I was not bothered by it. That is the legacy of the Thresher.

[genec]

According to Bruce Rule(why the USS Thresher SSN-593 was lost). Senior SOSUS analyst who gave closed-door testimony at the COI. Thresher did not suffer a flooding casualty. He agrees they suffered a reactor scram for unknown reasons, and that Thresher was at test depth when MCP's went offline. Thresher was slow and heavy, unable to blow MBT's and sank almost 8 mins later at a depth of 2400 feet. 500 feet below her calculated crush depth.

[TheGreatBirchTree]

Considering the immense size of the US sub fleet 52 years without a loss is astounding!