The link has several photos.

http://www.capecodtimes.com/ne...nates-55-years-later

Nuclear sub’s sinking off Cape resonates 55 years later

By Capt. Jim Bryant, USN (Ret.) / Contributing writer / Special to the Portsmouth Herald (NH)
Posted at 7:12 AM
Updated at 7:14 AM

On April 10, 1963, the American nuclear submarine USS Thresher, the world’s most advanced hunter-killer submarine, crushed at a depth of 2,400 feet, killing all 129 onboard, during a routine test dive.

Incredibly, more than a half-century later, details of the Thresher disaster remain poorly understood. Its shattered hull resides at the bottom of 8,400 feet of water, approximately 220 miles east of Cape Cod.

The underlying cause of the Thresher sinking 55 years ago, and the collisions last summer involving the USS John S. McCain and USS Fitzgerald that killed 17 sailors, was the failure to effectively integrate emerging technology into the training, procedures, planning and maintenance programs.

The world situation of then and now are similar as America rushes to maintain naval superiority with new weapons systems like the Littoral Combat Ship, Ford class nuclear aircraft carrier, and the Virginia class nuclear submarine. Insufficient crew training, manning and inadequate operating procedures and shipboard maintenance continue to cause avoidable, recurring at-sea incidents.

By 1963, Soviet submarines were a serious challenge to America’s national security. Thresher offered innovative improvements over earlier submarine designs. It was faster, quieter, dived deeper, and with advanced sonar and weapons systems, a significant threat to Soviet submarines.

Built by Portsmouth Naval Shipyard, Thresher was commissioned Aug. 3, 1961, and spent the following year testing weapons and new equipment, measuring radiated sound, shock testing and conducting exercises with other submarines with outstanding results. The ultimate test to challenge Soviet submarines would have to wait until after a lengthy maintenance period.

After shock testing using close-aboard explosive charges in July 1962, Thresher returned to Portsmouth Naval Shipyard for a series of upgrades and repairs.

On April 9, 1963, Thresher departed for sea trials, escorted by the submarine rescue vessel USS Skylark. After a shallow dive in the Gulf of Maine, the ships rendezvoused the following morning in deep water for a two-hour dive to Thresher’s deepest operating or test depth —1,300 feet, nearly twice as deep as previous classes.

hresher sank below its crush depth and imploded – raining its shattered hull, nuclear reactor and occupants onto the seabed below. The Navy’s investigation concluded that major flooding from ruptured piping in the engine room was the probable cause.

The sounds of the Thresher’s death throes were recorded by sound surveillance system (SOSUS) underwater hydrophones located around the world tuned to pluck machinery sounds of submarines out of all the noise in the ocean. SOSUS was a highly secret system designed to track Soviet submarine movements at long ranges. One SOSUS hydrophone arraywas located only 30 nautical miles from the site of Thresher’s sinking.

Bruce Rule was a top naval acoustic and SOSUS expert who analyzed Thresher’s death sounds and testified at the disaster inquiry. After leaving the Navy in September 1963, Rule spent his next 42 years as the lead acoustic analyst for the Office of Naval Intelligence. Though Rule’s testimony and findings remain classified, Rule recently revealed them in his book, “Why the USS Thresher (SSN 593) was lost,” which helps us understand this mystery beyond the obvious, that Thresher slowed, and uncorrectable negative buoyancy caused it to sink to crush depth.

Rule is positive there was no flooding because the sounds of high pressure water hitting the inside of the submarine were not detected. Low pressure steams or sprays of seawater (excessive leakage) from multiple sources would be quiet to SOSUS, increase negative buoyancy, and cause concern to the crew trying to isolate them.

SOSUS detected compressed air blowing seawater from the main ballast tanks twice. The MBT blow system that should have surfaced Thresher failed because of poor design and the unauthorized installation of strainers with a metal backing plate with a small hole, or orifice, that severely restricted air flow. Ice formed on the strainers as high-pressure air instantly cooled when released into a lower pressure environment.

Rule’s analysis of Thresher’s recorded acoustic signature and underwater telephone communications with the escort ship Skylark provides a timeline of Thresher’s loss.

At 8:53 a.m., Thresher descended from 1,000 to 1,300 feet (test depth). Possibly already negatively buoyant from not taking the time to adjust trim as the dive proceeded, increasing sea pressure on Thresher’s seawater systems boosted leakage. Somewhere between 8:53 and 9:09, Thresher experienced the stern plane problem, stopped to counter its effects, and started to sink.

At 9:09, SOSUS detected an electrical bus line-frequency instability, a symptom of an ongoing problem in the engine room, such as crew actions to stop excessive leakage from seawater piping. Shortly after the electrical bus started to waiver, SOSUS detected the sounds of compressed air blowing into the MBTs. This means the primary means of going shallow, main propulsion, was not usable. The blow stopped after 90 seconds due to ice blockage. This MBT blow did not remove enough seawater from the MBTs to reverse Thresher’s descent.

The submarine’s fate was sealed at 9:11 when SOSUS detected main coolant pumps stopping. This caused an automatic reactor shutdown (reactor scram) and by procedure, steam to be isolated to the main propulsion and power-generating turbines in the engine room.

The Navy’s investigative report describes communications at about 9:13 using the conflicting testimony of four witnesses on Skylark, “Experiencing minor difficulties. Have positive up angle. Am attempting to blow up. Will keep you informed.” The “experiencing minor difficulties” phrase is an enigma because Thresher had exceeded test depth, by as much as 600 feet, the reactor had scrammed, main propulsion was lost, the ineffective MBT blow failed to stop the downward acceleration, and the crew could hear the guttural sounds of the pressure hull compressing.

Garbled transmission at 9:17 was interpreted to contain the phrase “900 North,” understood to mean 900 feet below test depth or a depth of 2,200 feet. This is reasonable given that Thresher was reporting depth relative to test depth in case a Soviet submarine was listening.

SOSUS and Skylark detected hull collapse at 9:18 at a calculated depth of 2,400 feet with an energy pulse equal to the explosion of 22,500 pounds of TNT.

The 129 men did not die in vain. Their loss resulted in immediate changes to how the Navy built, maintained and operated its nuclear fleet.

Justifications for costly safety improvements are written in blood. In this case the Navy created the Submarine Safety (SUBSAFE) program that mandated the redesign of and strict quality control procedures for the manufacture, repair and testing of critical systems on submarines. New systems include a separate emergency MBT blow and emergency, remote, hydraulic seawater hull valve closure systems.

On Thresher, SUBSAFE would have prevented the unauthorized installation of the strainers and orifice plates. These critical systems include hull, seawater piping, high pressure air and stern plane. Until a submarine was SUBSAFE certified, it is restricted to operating at half its test depth.

No SUBSAFE-certified submarines have been lost despite terrible accidents like the San Francisco striking an underwater ridge in January 2005 at top speed that killed one sailor. The only other American nuclear submarine loss was in May 1968, when the Scorpion, which had not completed SUBSAFE-certification, suffered a main battery explosion before it sank and imploded.


— Capt. Jim Bryant served on three Thresher-class submarines, including commanding USS Guardfish (SSN 612) from 1987 to 1990. He was assisted in writing this article by a research and editing team of Harold Evans and Nicholas Wulfekuhle. Bryant lives in San Diego.

The fate of the Scorpion invites much controversy as to the cause of her demise. It was shadowing a Soviet surface action group and reported contact with a Soviet submarine prior to her loss. The naval board of inquiry findings indicate that the likely cause of the disaster was the detonation of a torpedo while the Scorpion's own crew attempted to disarm it. Subsequent analysis of the detailed Imagery taken of her wreck adds considerable speculation to the BOI’ initial findings..

In any event, Oh God, we pray thee that the memory of The crews of Thresher and Scorpion be ever sacred in our hearts,
... and that the sacrifice which they have offered for cause may be acceptable in thy sight.
... and may these sailors find repose with the sea in which he gave their lives that we might live. Into thy hands, oh Lord, we commend the souls of thy servants departed, now called unto eternal rest, and we commit them to the deep.

Was the Thresher one of the ones Cmdr. Ballard was searching for when he went looking for the Titanic? Or am I confused?

quote:

Originally posted by mbinky:
Was the Thresher one of the ones Cmdr. Ballard was searching for when he went looking for the Titanic? Or am I confused?

That was the Scorpion.

In exchange for loaning Ballard the deep diving mini-sub, IIRC, the Navy wanted photos of the wreck to see if they could refine a theory on her loss.

There is a memorial to both crews at the USS Albacore in Portsmouth NH. Quite the somber reminder to the dangers of undersea warfare.

My cousin, Lt Ron Babcock was on that sub. RIP, Ron!!

A older fellow I knew, lived alone in a trailer... one day I stopped at his place on the way to the general store and noticed he had a picture of his son in dress blues.

I asked about his son, he said he was a submariner, his ship was lost off of the Connecticut coast.

I understood this was indeed the Thresher.

Nice fellow, I’m glad I took the time to stop-in and say hello.

quote:

Originally posted by prairiefire:
My cousin, Lt Ron Babcock was on that sub. RIP, Ron!!

Fair winds and following seas Sir. And Thank you.

The Thresher incident was one of those things constantly drilled into our heads at the shipyard apprenticeship program at Mare Island submarine shipyard.

Their checks got cashed. RIP.

RIP to all our veterans who died in service to our great country.

So there has been a sunken and exploded nuclear reactor spewing radioactive shit into the ocean off Cape Cod for over 50 years? What are the health hazards of this? How much and what type of radioactive material was involved?

quote:

Originally posted by RaiseHal:
RIP to all our veterans who died in service to our great country.

So there has been a sunken and exploded nuclear reactor spewing radioactive shit into the ocean off Cape Cod for over 50 years? What are the health hazards of this? How much and what type of radioactive material was involved?

Google be yo' fren: http://www.seacoastonline.com/...30310/NEWS/303100355

quote:

Originally posted by Rey HRH:
The Thresher incident was one of those things constantly drilled into our heads at the shipyard apprenticeship program at Mare Island submarine shipyard.

Concur. SUBSAFE tenets were consistently cited. Aside anecdotes about USS Guitarro SSN-665 frequently entered such conversations as well about how things should never be done.

quote:

Originally posted by RAMIUS:

quote:

Originally posted by RaiseHal:
RIP to all our veterans who died in service to our great country.

So there has been a sunken and exploded nuclear reactor spewing radioactive shit into the ocean off Cape Cod for over 50 years? What are the health hazards of this? How much and what type of radioactive material was involved?

Google be yo' fren: http://www.seacoastonline.com/...30310/NEWS/303100355

Come on now, them be some BIG fish we're reeling in off the Cape. I like the legs the best.

quote:

Originally posted by Sigmund:
The underlying cause of the Thresher sinking 55 years ago

The MBT blow system that should have surfaced Thresher failed because of poor design and the unauthorized installation of strainers with a metal backing plate with a small hole, or orifice, that severely restricted air flow. Ice formed on the strainers as high-pressure air instantly cooled when released into a lower pressure environment.

This one fact seems to be the main reason that the sub couldn't surface. They tried to blow the ballast tanks, and couldn't. I also read somewhere that the air in this system to blow the tanks had been there for a very long time (days or weeks). Seems that subs don't tend to blow ballast tanks except for emergencies. So the temp of the air had cooled down to ambient (normally they would be hot from compression).

This seems to be a major design flaw that was corrected in later designs (I hope). So, when you release pressurized gas (air in this case) it will drop in temperature. Any moisture in this gas will freeze.

I was home on leave enroute to Sub School when this happened and it brought on a lot of negative advice from friends and family.

I served on a Thresher class boat from '72-'77 and it was a poorly designed class of boat. Compared to other classes, we had very little reserve buoyancy (The amount of water that could be taken on and still be able to surface). If I remember right, it was around 90 tons which wouldn't take any time at all if a 12-16 inch pipe/fitting failed at 1000 ft.

No one will ever know for sure what happened, but a book written by John Bently, titled The Thresher Disaster details a scenario that would have brought about the same results.