SEALAB I, II, and III were experimental underwater habitats developed by the United States Navy to prove the viability of saturation diving and humans living in isolation for extended periods of time. The knowledge gained from the SEALAB expeditions helped advance the science of deep sea diving and rescue, and contributed to the understanding of the psychological and physiological strains humans can endure.
SEALAB I was lowered off the coast of Bermuda in 1964 to a depth of 58 m (192 feet of seawater (fsw)) below the sea's surface. It was constructed from two converted floats and held in place with axles from railroad cars. The experiment involved four divers (LCDR Robert Thompson, MC; Gunners Mate First Class Lester Anderson, Chief Quartermaster Robert A. Barth, and Chief Hospital Corpsman Sanders Manning), who were to stay submerged for three weeks. The experiment was halted after 11 days due to an approaching tropical storm.
SEALAB I is now on display at The Museum of Man In the Sea, in Panama City Beach, Florida, near where it was initially tested offshore before being deployed. It is on outdoor display. Its metal hull is largely intact, though the paint is faded to a brick red. The interior has been largely stripped and deteriorated, as well as subjected to graffiti.
SEALAB II was launched in 1965, and unlike SEALAB I, it included hot showers and refrigeration. It was placed in the La Jolla Canyon off the coast of California, at a depth of 62 m. On August 28, 1965, the first of three teams of divers moved into what became known as the “Tilton Hilton” (Tiltin' Hilton, because of the slope of the landing site).
Each team spent 15 days in the habitat, but aquanaut/astronaut Scott Carpenter remained below for a record 30 days. In addition to physiological testing (described in the book by Radloff & Helmreich), the divers tested new tools, methods of salvage, and an electrically heated drysuit. They were aided by a bottlenose dolphin named Tuffy from the U.S. Navy Marine Mammal Program, who ferried supplies from the surface.
A sidenote from SEALAB II was a congratulatory telephone call that was arranged for Carpenter and President Lyndon B. Johnson. Carpenter was calling from a decompression chamber with helium gas replacing nitrogen, so Carpenter sounded unintelligible to operators. The tape of the call circulated for years among Navy divers before it was aired on NPR in 1999. [see the bottom of this page]
SEALAB III used a refurbished SEALAB II habitat, but was placed in water three times as deep. Five teams of nine divers were scheduled to spend 12 days each in the habitat, testing new salvage techniques and conducting oceanographic and fishery studies. Preparations for such a deep dive were extensive. In addition to many biomedical studies, work-up dives were conducted at the U.S. Navy Experimental Diving Unit at the Washington D.C. Navy Yard. These “dives” were not done in the open sea, but in a special hyperbaric chamber that could recreate the pressures at depths as great as 1,025 fsw (312 m).
According to John Craven, the US Navy's head of the Deep Submergence Systems Project of which Sealab was a part, Sealab III "was plagued with strange failures at the very start of operations". On February 15, 1969, SEALAB III was lowered to 610 fsw (185 m), off San Clemente Island, California. The habitat soon began to leak and six divers were sent to repair it, but they were unsuccessful. Tragically, during the second attempt, aquanaut Barry Cannon died. It was later found that his breathing apparatus was missing baralime, the chemical necessary to remove carbon dioxide. According to Craven, while the other five divers were undergoing the week-long decompression, repeated attempts were made to sabotage their air supply by someone onboard the command barge. Eventually, a guard was posted on the decompression chamber and the men were recovered safely. A potentially unstable suspect was identified by the staff psychiatrist but the culprit was never prosecuted. Craven suggests this may have been done to spare the Navy bad press so soon after the USS Pueblo incident. The SEALAB program came to a halt, and although the habitat was retrieved, it was eventually scrapped. Aspects of the research continued in classified military programs, but no new habitats were built.
NCEL of Port Hueneme, CA (now a part of NFESC), was responsible for the handling of several contracts involving life support systems used on SEALAB III.
book on SEALAB
Thank you to Francis French for pointing out the limited availability of
this book on SEALAB currently available HERE