USS Scorpion (SSN-589) was a Skipjack-class nuclear-powered submarine that served in the United States Navy, the sixth vessel and second submarine to carry that name.
Scorpion imploded and sank on May 22, 1968. She is one of two nuclear submarines that the U.S. Navy has lost, the other being . She was one of the four submarine disappearances in 1968, the others being the Israeli submarine , the , and the .
The wreckage of Scorpion remains in the North Atlantic Ocean with all of her armaments and her nuclear reactor.
Service
Scorpions keel was laid down 20 August 1958 by General Dynamics Electric Boat in Groton, Connecticut. She was launched 19 December 1959, sponsored by Elizabeth S. Morrison, the daughter of Lieutenant Commander Maximilian Gmelich Schmidt, the final commander of the similarly-named World War II-era which had been lost with all hands in 1944. The newer Scorpion was commissioned 29 July 1960, with Commander Norman B. Bessac in command.
Service: 1960–1967 Assigned to Submarine Squadron 6, Division 62, Scorpion departed New London, Connecticut, on 24 August for a two-month European deployment. During that time, she participated in exercises with 6th Fleet units and NATO-member navies. After returning to New England in late October, she trained along the Eastern Seaboard until May 1961. On 9 August 1961, she returned to New London, moving to Norfolk, Virginia, a month later. In 1962, she earned a Navy Unit Commendation. "Naval Unit Commendation"
Norfolk was Scorpions homeport for the remainder of her career, and she specialized in developing nuclear submarine warfare tactics. Varying roles from hunter to hunted, she participated in exercises along the Atlantic Coast, and in Bermuda and Puerto Rico operating areas. From June 1963 to May 1964, she underwent an overhaul at Charleston. She resumed duty in late spring, but regular duties were again interrupted from 4 August to 8 October for a transatlantic patrol. In the spring of 1965, she conducted a similar patrol in European waters.
In 1966, she deployed for special operations. After completing those assignments, her commanding officer received a Navy Commendation Medal for outstanding leadership, foresight, and professional skill. Other Scorpion officers and crewmen were also cited for meritorious achievement. Scorpion is reputed to have entered an inland Russian sea during a "Northern Run" in 1966, where the crew filmed a Soviet missile launch through her periscope before fleeing from Soviet Navy ships.
Overhaul: 1967 On 1 February 1967, Scorpion entered Norfolk Naval Shipyard for a refueling overhaul. Instead of a much-needed complete overhaul, though, she received only emergency repairs to get quickly back on duty. The preferred SUBSAFE program required increased submarine overhaul times, from 9 to 36 months. SUBSAFE required intensive vetting of submarine component quality, coupled with various improvements and intensified structural inspections – particularly of hull welding, using ultrasonic testing.
Cold War pressures had prompted U.S. Submarine Force Atlantic (SUBLANT) officers to cut corners. The last overhaul of the Scorpion cost one-seventh of those performed on other nuclear submarines at the same time. This was the result of concerns about the "high percentage of time offline" for nuclear attack submarines, estimated at 40% of total available duty time.
Scorpions original "full overhaul" was reduced in scope. Long-overdue SUBSAFE work, such as a new central valve control system, was not performed. Crucially, her emergency system was not corrected for the same problems that destroyed Thresher. While Charleston Naval Shipyard claimed the emergency main ballast tank blow (EMBT) system worked as-is, SUBLANT claimed it did not, and their EMBT was "tagged out" (listed as unusable). Perceived problems with overhaul duration led to a delay on all SUBSAFE work in 1967.
Chief of Naval Operations Admiral David Lamar McDonald approved Scorpions reduced overhaul on 17 June 1966. On 20 July, McDonald deferred SUBSAFE extensions, otherwise deemed essential since 1963.
Service: 1967–1968
In late October 1967, Scorpion started refresher training and weapons-system acceptance tests, and was given a new commanding officer, Francis Slattery. Following type training out of Norfolk, Virginia, she got underway on 15 February 1968 for a Mediterranean Sea deployment. She operated with the 6th Fleet into May and then headed west for home.
Scorpion suffered several mechanical malfunctions, including a chronic problem with freon leakage from refrigeration systems. An electrical fire occurred in an escape trunk when a water leak shorted out a shore power connection. No evidence was found that Scorpions speed was restricted in May 1968, although it was conservatively observing a depth limitation of , due to the incomplete implementation of planned post-Thresher safety checks and modifications.
After departing the Mediterranean on 16 May, Scorpion dropped two men at Naval Station Rota in Spain, one for a family emergency and one for health reasons. Some U.S. ballistic missile submarines (SSBNs) operated from the U.S. naval base Rota; USS Scorpion is thought to have provided noise cover for when they both departed to the Atlantic. Along with Soviet intelligence trawlers, Soviet fast nuclear attack submarines were attempting to detect and follow the U.S. submarines leaving Rota; in this case, two fast 32-knot hunter-killer subs.
Scorpion was then detailed to observe Soviet naval activities in the Atlantic in the vicinity of the Azores. An Echo II-class submarine was operating with this Soviet task force, as well as a Russian guided-missile destroyer. Having observed and listened to the Soviet units, Scorpion prepared to head back to Naval Station Norfolk.
Disappearance: May 1968 Scorpion attempted to send radio traffic to Naval Station Rota for an unusually long period beginning shortly before midnight on 20 May and ending after midnight on 21 May, but was only able to reach a Navy communications station in Nea Makri, Greece, which forwarded the messages to COMSUBLANT. Lt. John Roberts was handed Commander Slattery's last message that he was closing on the Soviet submarine K-135 and research group, running at a steady at a depth of "to begin surveillance of the Soviets." Scorpion was expected to arrive at her homeport of Norfolk, Virginia, on 27 May at 1300 local time. After she was overdue for several hours, the Atlantic fleet launched a sea and air search during the peak search period from 28 to 30 May involving as many as 55 ships and 35 search aircraft. A brief radio message including Scorpion's codename Brandywine was received by several search parties on the evening of 29 May. The source could not be identified in the search area derived from the bearings of the radio message.
Search: 1968
The Navy suspected possible failure and launched a search. Scorpion and her crew were declared "presumed lost" on 5 June. Her name was struck from the Naval Vessel Register on 30 June. The search continued with a team of mathematical consultants led by John Piña Craven, the chief scientist of the Navy's Special Projects Division. They employed the methods of Bayesian search theory, initially developed during the search for a hydrogen bomb lost off the coast of Palomares, Spain, in January 1966 in the Palomares B-52 crash.
Some reports indicate that a large and secret search was launched three days before Scorpion was expected back from patrol. This and other declassified information led to speculation that the Navy knew of Scorpions destruction before the public search was launched.
At the end of October 1968, the Navy's oceanographic research ship located sections of the hull of Scorpion on the seabed, about southwest of the Azores under more than of water. This was after the Navy had released sound tapes from its underwater SOSUS listening system, which contained the sounds of the destruction of Scorpion. The court of inquiry was subsequently reconvened, and other vessels, including the bathyscaphe Trieste II, were dispatched to the scene to collect pictures and other data.
Craven received much credit for locating the wreckage of Scorpion, although Gordon Hamilton was instrumental in defining a compact "search box" wherein the wreck was ultimately found. He was an acoustics expert who pioneered the use of hydroacoustics to pinpoint Polaris missile splashdown locations, and he had established a listening station in the Canary Islands, which obtained a clear signal of the vessel's pressure hull imploding as it passed crush depth. Naval Research Laboratory scientist Chester Buchanan used a towed camera sled of his own design aboard Mizar and finally located Scorpion.
Observed damage
The bow of Scorpion appears to have skidded upon impact with the globigerina ooze on the sea floor, digging a sizable trench. The sail had been dislodged, as the hull of the operations compartment upon which it perched disintegrated, and was lying on its port side. One of Scorpions running lights was in the open position, as if it had been on the surface at the time of the mishap, although it may have been left in the open position during the vessel's recent nighttime stop at Rota. One Trieste II pilot who dived on Scorpion said that the shock of the implosion might have knocked the light into the open position.
The secondary Navy investigation – using extensive photographic, video, and eyewitness inspections of the wreckage in 1969 – suggested that Scorpions hull imploded as it sank below crush depth. The Structural Analysis Group, which included Naval Ship Systems Command's Submarine Structures director Peter Palermo, plainly saw that the torpedo room was intact, though pinched by excessive sea pressure. The operations compartment collapsed at frame 33, this being the king frame of the hull, reaching its structural limit first. The conical/cylindrical transition piece at frame 67 followed instantly. The boat was broken in two by massive hydrostatic pressure at an estimated depth of . The operations compartment was largely obliterated by sea pressure, and the engine room had telescoped forward into the hull due to collapse pressure, when the cone-to-cylinder transition junction failed between the auxiliary machine space and the engine room.
The only damage to the torpedo room compartment was the missing hatch of the forward escape trunk. Palermo pointed out that this would have occurred when water pressure entered the torpedo room at the moment of implosion.
The sail was ripped off, as the hull beneath it folded inward. The propulsion shaft came out of the boat; the engineering section had collapsed inward in a telescoping fashion. The broken boat fell another to the ocean floor.
Photos taken in 1986 by Alvin, released by the Navy in 2012, show the broken inboard end of the propulsion shaft.
Navy investigations
Court of inquiry report: 1968 Shortly after her sinking, the Navy assembled a court of inquiry to investigate the incident and to publish a report regarding the likely causes. The court was presided over by Vice Admiral Bernard L. Austin, who had presided over the inquiry into the loss of . The report's findings were first made public on 31 January 1969. While ruling out sabotage, the report said: "The certain cause of the loss of the Scorpion cannot be ascertained from evidence now available."
In 1984, the Norfolk Virginian-Pilot and The Ledger-Star obtained documents related to the inquiry, and reported the disaster was likely caused by a torpedo that exploded when the crew tried to disarm it. The U.S. Navy declassified many of the inquiry's documents in 1993.
Naval Ordnance Laboratory report: 1970