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| Date | June 17, 1973 (1973-06-17) |
|---|---|
| Location | OffKey West |
| Cause | Entangled submersible |
| Participants | Archibald Menzies, Robert Meek, Edwin Clayton Link, Albert Dennison Stover |
| Outcome | Successful rescue of Menzies and Meek; recovery of bodies of Link and Stover |
TheJohnson Sea Link accident was a June 1973 incident that claimed the lives of two divers. During a seemingly routine dive offKey West, thesubmersibleJohnson Sea Link was trapped for over 24 hours in the wreckage of the destroyerUSS Fred T. Berry, which had been sunk to create anartificial reef. Although the submersible was eventually recovered by the rescue vesselA.B. Wood II, two of the four occupants died ofcarbon dioxide poisoning: 31-year-old Edwin Clayton Link (son ofEdwin Albert Link, the submersible's designer) and 51-year-old diver Albert Dennison Stover. The submersible's pilot, Archibald "Jock" Menzies, andichthyologist Robert Meek survived.[1][2][3] Over the next two years, Edwin Link designed an unmanned Cabled Observation and Rescue Device (CORD) that could free a trapped submersible.[4][5]
TheJohnson Sea Link was the successor to Edwin Link's previous submersible,Deep Diver, the first small submersible designed for lockout diving. In 1968 theBureau of Ships determined thatDeep Diver was unsafe for use at great depths or in extremely cold temperatures because of the substitution of the wrong kind of steel, which became brittle in cold water, in some parts of the submersible.[6] Link proceeded to design a new lockout submersible with a distinctive acrylic bubble as the forward pilot/observer compartment. In January 1971 the new submersible was launched and commissioned to theSmithsonian Institution. It was named theJohnson Sea Link after its donors, Link and his friendJohn Seward Johnson I.[4][6]
TheJohnson Sea Link carried a crew of four in two separate compartments. The aft compartment was designed for lockout diving, allowing two divers to be compressed to the ambient pressure of the ocean and leave the submersible to work underwater. The forward pilot's compartment was an acrylic sphere with a diameter of 5 feet (1.5 m), providing a panoramic underwater view for the pilot and an observer.[6][7] Anair conditioning unit was installed on the aft starboard side of the acrylic sphere, creating a blind spot for the pilot.[2]
After two years of successful operations, on June 17, 1973, theJohnson Sea Link was launched from Edwin Link's research ship, theSea Diver, 15 miles (24 km) out fromKey West, Florida. The objective of the mission was to recover afish trap from the destroyerUSS Fred T. Berry, which had been sunk to create an artificial reef.[2][5] This was Dive 130 of theJohnson Sea Link.[2] TheSea Link crew that day consisted of:
According to the subsequentUnited States Coast Guard report on the accident, Menzies, Link and Stover "displayed an incredible casualness in their preparations for Dive 130, considering the inherent hazards of their operation."[5][9] Because Link and Stover were not planning to perform a lockout dive, they were dressed in shorts and T-shirts. Prior to entering the submersible, Meek noticed Link and Stover's clothing and commented to them that it was cold "down there".[10]
The attempt to retrieve the fish trap failed. Shortly after 9:45 a.m, theSea Link became entangled on a cable in theFred T. Berry's wreckage while moving away from the sunken ship, 360 feet (110 m) below the ocean surface.[2][5] TheSea Diver informed the U.S. Coast Guard of the situation and requested the assistance ofNavy divers, but conveyed that theSea Link was in "no immediate danger".[11] The Navy dispatched thesubmarine rescue shipUSS Tringa (ASR-16) from Key West.[2][5]
TheSea Link andSea Diver crews considered whether to use the submersible's lockout capacity to allow one of the men in the diving compartment to exit the submersible and attempt to free it from the cable. This plan was abandoned because it posed a danger ofoxygen toxicity to Link and Stover in the diving chamber. TheSea Link crew and Edwin Link, who was in overall charge of the situation, agreed to await theTringa's arrival.[2] Levels ofcarbon dioxide (CO2) began to rise in the pilot compartment when the CO2 scrubber failed. Menzies took off his shirt, emptied the carbon dioxide absorbentBaralyme from the scrubber canister into it and held it in front of the circulating fans of the air conditioning unit, lowering the CO2 level in the pilot's cabin. TheSea Diver crew calculated that the CO2 in the submersible could be maintained at acceptable levels for 42 hours in the pilot compartment and 61 hours in the diver compartment. These calculations, however, did not take into account that the Baralyme in the diver compartment would be rendered less effective by low temperatures.[2][5] The acrylic plastic hull of the pilot compartment had a lowerheat transfer coefficient than thealuminum hull of the diver compartment, allowing it to remain at a higher temperature.[12]
TheTringa arrived on scene at about 4:15 p.m. and proceeded to make a four-pointmoor above theSea Link.[2] By the evening of June 17 the internal temperature of the aluminum diver compartment had dropped to near the temperature of the surrounding ocean, and was possibly as low as 45 °F (7 °C).[2][5][12] By 10 p.m. the absorbent capability of the diver compartment Baralyme was exhausted. At 10:25 p.m. Link and Stover began breathing from air supplied masks. Twohard hat divers from theTringa attempted to descend to theSea Link, but had to turn back when their progress was impeded by the hull of theBerry. A lockout dive by Link and Stover was considered, but they again expressed their desire not to lock out, and Pilot Menzies and theSea Diver crew agreed.[2][5] A lockout dive was considered again at 12:38 a.m. on June 18, but by this time Link and Stover were too cold to attempt such a dive. They had switched over to ahelium-oxygen breathing mixture, resulting in rapid body heat loss. The atmospheric pressure in the diver's compartment had by now increased to the ambient pressure of the ocean at theSea Link's depth (approximately 12 standard atmospheres (1,200 kPa)).[2]
At 1:12 a.m. Menzies reported to the surface that Link and Stover were sufferingconvulsions. There was no further audio communication with Link and Stover after this point. A second rescue dive from theTringa was again unsuccessful, as was the attempted use of a Roving Diving Bell lowered from theTringa later that morning.[2] The submersiblePerry Cubmarine attempted to search the bottom, but was hampered by an inoperativesonar.[2][13]
On the afternoon of June 18, the commercialsalvage vesselA.B. Wood II (O.N. 501922) arrived on the scene carrying an underwater television camera with a maneuverable platform,[2][5] a device from the Naval Ordnance Laboratory inFort Lauderdale, Florida.[14] After the camera was used to locate theSea Link, agrappling hook was attached to the camera and used to engage one of theSea Link's propeller shrouds and bring it to the surface. TheSea Link surfaced at 4:53 p.m. on June 18.[2][5]
Menzies and Meek could immediately be removed from theSea Link and were transferred to thedecompression chamber aboard theTringa. However, with the diver's compartment still pressurized, any attempt to remove Link and Stover would have been fatal to them if they were still alive. TheSea Link was transferred aboard theSea Diver. Link and Stover were visible through the diving compartment's view ports, but showed no vital signs. The compartment was force ventilated with a helium-oxygen mixture while remaining pressurized, and hot water was sprayed over it in an attempt to raise its internal temperature. On the morning of June 19, medical doctors concluded that Link and Stover were dead, and the compartment was depressurized.[2][5] Link and Stover were brought to the Florida Keys Memorial Hospital on Key West, where their autopsies were performed.[2] Both men's cause of death was listed as "Respiratory Acidosis due toCarbon Dioxide Poisoning".[15]
TheJohnson Sea Link accident was investigated by the United States Coast Guard. The investigators concluded that the accident was caused bypilot error, possibly due to distraction, and by the hull shape of theSea Link.[2][5] According to the investigators, "The submersible's modular construction of irregular shapes, projections, and appendages provide an excellent configuration for ensnarement by almost any type of obstruction."[9]
In addition to the U.S. Coast Guard investigation, the Smithsonian Institution commissioned an in-house investigation, review and report. That report, titled "Report of the Johnson-Sea-Link Expert Review Panel to The Secretary, Smithsonian Institution, December 21, 1973", totaling 121 pages, provided specific observations and recommendations for changes in the design and operation of the submersible. That report was never issued to the public.
Basic conclusions from the internal investigation were (paraphrased):
a. A combination of key engineering and operational decisions contributed to the entrapment and loss of life.
b. The developmental craft is a basically sound and safe system not yet fully developed (as of 1973) and completion and correct observation of the craft can be done safely.
c. Menzies and Meek performed admirably, as did the rescue team, and circumstances beyond their control led to the loss of life.
Edwin Link spent the following two years designing an unmanned Cabled Observation and Rescue Device (CORD) that could free a trapped submersible.[4][5] A secondJohnson Sea Link submersible, nearly identical to the first, was launched in 1975.[4][5][7] The two submersibles remained in operation for many years, examining the wreck of theUSS Monitor in 1977 and helping recover the wreckage of theSpace ShuttleChallenger after itsdestruction in 1986,[7] but were retired in 2011.[16] The 1974 television movieTrapped Beneath the Sea, starringLee J. Cobb, was loosely based on theJohnson Sea Link accident.[17][unreliable source?]
The Link Foundation established the Albert D. Stover/E. Clayton Link Fund, used to support scholarships and oceanographic research, in 1973.[18] In 1978, Compass Publications established the National Ocean Industries Association Safety in Seas Award, partly in memory of Link and Stover.[19]
Shipwrecks and maritime incidents in 1973 | |
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| Shipwrecks |
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| Other incidents |
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24°28′24″N81°33′32″W / 24.4734°N 81.5589°W /24.4734; -81.5589
