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Looking Back, 1963

In this fortieth anniversary year of the loss of USS THRESHER (SSN 593) it is incumbent on us to review the story of the loss of THRESHER, the search for the submarine, the search for the causes, and the legacy of that loss. The search by the bathyscaph TRIESTE for the submarine is summarized here. The narrative of the loss of THRESHER and the lessons learned, bought at so great a price, were examined in 1963 by the Naval Court of Inquiry’ and the Congressional Hearings of the Joint Committee on Atomic Energy.2 The challenge for submarine leaders is to study these documents and to reinterpret and apply them for each new generation of submarines and submariners.

Mistakes start early in the chain of events that lead to a tragedy. They can be overlooked in the euphoria of new design, the promise of technology, and the press of operational commitments. Add to this the reality of budget constraints and the loss of skilled work-men and leadership over time. Our submarine safety record is excellent. Yet, safety precepts can erode in forty years.

The Navy’s challenges and technology were very different in 1963. The U.S. was in a Cold War with the Soviet Union. They were aggressively becoming a Blue Water Navy with global ambitions. President Kennedy had successfully used the Navy to foil the Soviets in the Cuban Missile Crisis just the year before. We were designing, building and training a nuclear powered submarine fleet.

At the same time, we lived in the Davy Jones Locker era: ships and sailors lost at sea were forever confined to the deep, and the deep guards its secrets well. The Mccann Bell was the extent of submarine rescue capability. Deep submergence was a new idea demonstrated by the bathyscaph TRIESTE, which conquered the Challenger Deep in the Pacific, 35,800 feet, in 1960.3 (I volunteered for bathyscaph duty in 1962 and in 1963 was one of the two submariners who piloted her to search for THRESHER.)


THRESHER was the lead ship in a new class of attack ASW submarines whose mission was to counter the growing threat of Soviet diesel and nuclear powered submarines. THRESHER was designed to dive deeper, go faster and more quietly, and to carry a more formidable payload than any previous submarine, U.S. or foreign . THRESHER had a modified SKIPJACK hull form with a single propeller and rudder, powered by the S-5-W pressurized water reactor. She had a deeper test depth than did SKIP JACK. Both were made of HY-80 steel. The 593 boat had the new BQQ-2 sonar, positioned on the nose for better listening. She was armed with torpedoes and the developmental SUBROC weapon system. The promise of this new submarine, and the urgent need for its operational employment, were such that fourteen ships of its class were authorized in the years 1958 to 1961.

The submarine was built by the Portsmouth Naval Shipyard, (PNS), launched in 1961 and commissioned in 1962. The commissioning commanding officer was Commander Dean Axene. THRESHER went through its initial period of shakedown with sea trials and operational testing. This included a series of depth charges exploded near the hull. Residual damage from this test was continuously uncovered before and during the upcoming availability.

After shakedown, THRESHER returned to Portsmouth for Post Shakedown Availability (PSA) in August 1962. The planned six month duration was extended to nine months for both originally scheduled work and for new work. The latter included repairs of damage resulting from the shock tests. During the extended PSA key personnel were rotated to new duty stations. The assistant ship superintendent and ship superintendent transferred in November and December. In January 1963, the CO, Commander Axene was relieved by Lieutenant Commander J. Wes Harvey, and the XO, Lieutenant Commander William Cowhill, was relieved by Lieutenant Pat Garner.

THRESHER completed its in port test requirements including afast cruise alongside the dock April I, and got underway April 9, 1963 for sea. She proceeded to the operations area for the initial tests. Accompanying her was USS SKYLARK, a submarine rescue ship with a McCann Bell on board. The McCann Bell had a rescue capability to 850 feet under ideal operating conditions.\

Early on April 10 the submarine and rescue ship had moved to deeper waters for the test depth phase. The known sequence of events that followed is contained in the Navy Court of Inquiry record of findings :

“That at 0747R THRESHER reported by underwater telephone that she was starting a deep dive …. SKYLARK then maintained her approximate position. THRESHER reported course changes and depth changes, but SKYLARK did not plot THRESHER’s position.

That the deep dive appeared to SKYLARK personnel to proceed satisfactorily until about 0913R when THRESHER reported to SKYLARK to the effect, ‘Experiencing minor difficulties. Have positive up angle. Am attempting to blow. Will keep you in- formed.’

That at about 09 l 6R SKYLARK heard a garbled transmission which was believed to contain the words ‘ … test depth. An additional garbed transmission was received about 09 l 7R reported as containing the words ‘ … nine hundred north’.

SKYLARK proceeded to search the area for signs of the submarine. Finding none, she sent out a message to ComSubFlot Two in New London, saying she had lost contact with THRESHER.

Commanders sent out immediate orders for ships, submarines and aircraft to proceed to the operations area to look for the submarine. They found an oil slick, rubber gloves, and pieces of plastic. They did not find anything to give them hope. The story was carried on the evening news. The CNO, Admiral George Anderson, officially announced that THRESHER was overdue and presumed lost with all hands. The location was 270 miles east of Boston. All hands totaled 129 men: ship’s company of 12 officers and 96 crew, plus one ComSubLant staff officer, and from the shipyard: 3 officers, 13 civilians, and 4 contractor representatives.

Within a few days, secret SOSUS information (later declassified), was added to the testimony before the Court of Inquiry findings of fact:

” … Commander Oceanographic Systems Atlantic obtained information that, at 0911 R, the propulsion plant stopped or slowed, and that a high energy, low frequency noise disturbance of the type which could have been made by an implosion emanated from THRESHER at 0918. l R. There were also indications of two disturbances, one extending from 0909.8R to 091 I .3R, the other from 0913.5R to 0914R, which could have been made by the blowing of ballast tanks.”

Bathyscaph TRIESTE Ordered to Boston

On the way home at 1800 West Coast time, I stopped at the Navy Electronics Laboratory waterfront gate on Point Loma. The guard came over to my car looking upset. He asked if I had heard the news: a submarine was down in the Atlantic. I was surprised, and skeptical. Submarines were known to surface with a flooded antenna cable preventing communications. When I arrived home, one look at my wife’s face confirmed the news. Two media organizations had called my home to ask for information about the tragic story already on the news. As I sat down to supper Lieutenant Commander Keach, the officer-in-charge bathyscaph TRIESTE called, “Be at the TRIESTE compound by 1930.”

The bathyscaph TRIESTE was the Navy’s experimental deep submersible operated by the Navy Electronics Laboratory, San Diego. The bathyscaph consisted of a pressure proof sphere for the pilot and observer, stoutly bolted to a lightweight float containing 35,000 gallons of gasoline. The gasoline provided buoyancy for the five ton sphere. Two submarine officers were assigned as pilots. To conduct a dive one pilot operated the submersible and the other was the topside safety officer. We had a crew of eight enlisted and a team of civil service personnel. 6 Our mission at that time was ASW research. We took scientists into the deep to examine with their eyes and instruments the water column and sea floor.

The conference that evening was brief. All we knew was the name of the submarine and the location, 270 miles east of Boston. We studied the chart which showed the submarine was on the rugged continental slope where the depth of water was about 8,500 feet That depth was well beyond any rescue or salvage capability. Keach was called to the phone. It was an aide to CNO. Can you find the submarine? Keach told him that we had the depth capability but we didn’t have much search capability. The aide hung up.

Captain Mason, CO of the laboratory, told us to start preparations to go to the East Coast, “in case you are called”. Where, when, how was to be determined later.

The orders came the next day. We packed up the bathyscaph, replenishment stores and the eight man crew, and loaded all onto POINT DEFIANCE (LSD-31) on Easter Sunday. That afternoon we sailed for Boston via the Panama Canal. We arrived in Boston April 28 and made preparations including a test dive to 700 feet. Expecting immediate orders to sea, we were disappointed when we were ordered to “standby”, pending results from the ships searching for THRESHER.

A debate took place at high levels of government and the Navy. Some wanted to call off the search and let the bereaved families find rest from the constant media attention. The Navy decided to continue the search because of the need to try to find clues to the sinking from the submarine itself.

Three more of the class were already at sea: PERMIT, PLUNGER, and BARB.

The country was shocked by the loss of 129 men at sea on a nuclear submarine. They were also worried whether there was harmful radiation escaping from the reactor. The intensity of the aroused public was reflected in the Congress. The Joint Committee on Atomic Energy opened hearings on June 26, 1963 to investigate the loss.

The crucial question was: could the experimental submersible find something of value to the investigation? TRIESTE was the only capability the U.S. had that could take investigators to 8500 feet and return safely to the surface. 8 (A round trip we called it). TRIESTE’s usefulness was not as a search vehicle but as an inspection vehicle. This understanding was not apparent to those outside our team. After months of watching our at-sea performance it became clear to all.

The bathyscaph was simple in concept and elegant in design, but the float containing the gasoline was as fragile as a raw egg. TRIESTE had to be towed to the diving point, rigged for dive topside, underwater and in the sphere. Following each dive, steel ballast and gasoline were replenished, batteries recharged and equipment repaired. 9 The bathyscaph’s one foot of free board made these surface operations hazardous in anything but calm seas.

TRIESTE had a simple compass, two view ports, deep sea lights and cameras. Submerged, automobile batteries provided propulsion of one knot for four to six hours. The swath width for visual search purposes was fifty feet.

Searching the Deep

Captain Frank Andrews, ComSubDevGru 2, squadron commander for THRESHER, was given command of the search force. 10 Navy oceanographic ships were ordered to the area. Search plans were quickly devised and continually revised. Locating an object as small as a 278 foot submarine displacing 4300 tons is a difficult problem in a vast three dimensional ocean.

The basic plan was for the ships to search the area and locate the THRESHER. After the submarine was determined to be within an area two miles by two miles, the bathyscaph would take inspectors down to see and photograph the scene. From this visual inspection they hoped to find clues as to the cause of the sinking. A significant limitation to the search operation was navigation and underwater location relative to a known position. This combined with the narrow search width of the bathyscaph relative to the area to be surveyed, made underwater search as much a matter of luck The oceanographic ships developed a bathymetric as skill. survey of the area using precision depth finders. Then with deep cameras and magnetometers they combed the bottom for clues and anomalies. After eight weeks the data, though fragmentary, fit into an area thought to be within the capability of TRIESTE. We were ordered to sea on June 19. After two months on standby for orders we were relieved, yet not without concerns. What we would do and how had been discussed with Captain Andrew’s assistant, Lieutenant Commander Art Gilmore.

TRIESTE made two series of five dives that summer of 1963, in the vicinity of the debris field established by the surface ships. We were towed the 270 miles to the area by USS PRESERVER (ARS 8), and she was our tender ship for the entire summer. The first series of dives produced some photographs of debris and a plastic slipper with the letters SSN 5 showing. The significant result for the Bathyscaph team working with PRESERVER was learning to replenish at sea instead of returning to port for that chore. After the fifth dive, TRIESTE was towed back to Boston for repairs and upgrades. 14 The work included additional battery capacity, new radiation and magnetometer sensors, and what turned out to be the most fortuitous upgrade, a mechanical arm.

On August 19, the bathyscaph returned to the search area for a second series of dives. As the weather was beginning to deteriorate the pressure to dive and find something increased. One rig-for-dive was aborted because sea water poured down the sphere access trunk every time the sailor or I opened the topside hatch. After an hour of bailing by hand we had admitted more sea water than we emitted.

Our luck changed on dive three when Keach came upon large pieces of crumpled steel scattered around the seafloor. (These were photographed and later determined to be the steel dome of the BQQ-2 sonar.) With little time remaining on the batteries, he selected a five foot piece of pipe and maneuvered TRIESTE into position over it. Using the newly attached mechanical arm, he captured the pipe and slowly ascended. He stopped the ascent at 100 feet and called for divers to come down and secure the pipe with lines and bring it safely to the surface.

Radiation checks had been made in the surrounding area via water samples and sea floor core samples. Nothing above normal background was found in those samples. However this was the first piece of metal from the wreckage to be brought to the surface. It was by no means certain that it would be free from dangerous radiation. On deck an anxious diver held the pipe. We relaxed when the instrument recorded normal background radiation. The pipe had etched into it the words, 593 boat, and a drawing number that was later determined to be from the galley.

After weeks of being towed at sea and working in the seaway the bathyscaph float showed signs of wear that could not be fixed while it was full of gasoline. PRESERVER towed TRIESTE to Boston. It was September 1, and the evening sky held portent of winter approaching.

On September 5, Secretary of the Navy Frank Korth held a news conference and announced:

“The location of structural parts of THRESHER on the ocean floor having been positively confirmed by the bathyscaph TRIESTE during her latest series of successful dives, I have today directed that the associated operational aspects of the search for the nuclear submarine THRESHER be terminated.”

Secretary Korth went on to state that the Navy planned to continue the search as a research project and not an operational one.

The Search Continues. 1963-1964

The continued search was conducted under the Office of Naval Research. Captain Andrews retired from the Navy and took over as the director of the search. The USNS MIZAR was operated by the Naval Research Laboratory and headed by Chester Buchanan, chief scientist. He installed improved surface navigation equipment, an experimental underwater tracking system and an improved towed sled. MIZAR located her position relative to a bottom datum and to the position of the sled she towed. The sled was upgraded with a side scan sonar in addition to the lights, cameras, and magnetometers previously used. Over the winter of 1963-1964, Buchanan used this new capability to make a comprehensive survey of the THRESHER area and produced a photo mosaic of visible portions of the submarine.

Substantial improvements were made to the bathyscaph. A new float was designed, built and mated to the sphere, and renamed TRIESTE II.

The officer watch was relieved during the spring, Lieutenant Commander Brad Mooney became officer-in-charge. Lieutenant Larry Shumaker returned to the project and a third officer came aboard, Lieutenant John Howland. 16 Trial and training dives followed near San Diego. TRIESTE II was transported by ship to Boston for another dive series. In May, Mooney and his team arrived, set up base at the Boston Navy Yard, and made preparations to return to sea.

TRIESTE H’s first dive in the THRESHER area turned into the only dive of the series. The propulsion motors quit shortly after being turned on. Mooney, the pilot, drifted with the current and came upon the debris field. He chose to surface rather than risk drifting into a piece of wreckage. After they surfaced, they found that the battery had shorted burning a hole into the gasoline filled float. Back to Boston they went where further inspection showed that the electric motors and most of the external electrical system had to be replaced. The work was completed in time for a second dive series to begin before the weather prevented safe operations at sea.

A second series of dives was begun in August with dramatic results. On dive four Mooney was the pilot and Howland and Andrews (search commander) were observers. Shumaker was topside safety officer. The bathyscaph landed on what they thought was the sea floor. After letting the customary cloud of silt settle, Mooney realized that he was sitting on top of something because he could see the sea floor below. He rotated the craft 90 degrees horizontally. As his eyes became accustomed to the eerie light from the external lamps he made out the silhouette of part of the submarine hull. He had landed TRIESTE right on top of the elusive submarine. Further examination showed they had found the main section of the hull. As the lights dimmed from the diminishing batteries they lifted off and rose to the surface and daylight.


The search results can be summarized as follows:

  • Mizar, a specially equipped ship, used deep towed cameras and instruments to locate and photograph the submarine debris and shrink the search area.
  • The bathyscaph TRIESTE took inspectors to examine and photograph the wreckage, and retrieve the pipe.
  • Tangible evidence obtained by the search team proved that
    the wreckage was indeed the sunken submarine THRESHER. The Navy used this evidence to publicly state the search results in positive terms and bring a measure of closure to the tragedy.
  • This success, however limited and with whatever problems yet to be overcome, made an important beginning in the field of deep submergence search and inspection. That team was used again to find SCORPION in 1968-1969.

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