People Under the Sea: Habitats - SEALAB

SEALAB I was not a glamorous habitat. Constructed of two converted floats, it was lowered off the coast of Bermuda in July of 1964—and weighted in place with axles from railroad cars. The plan was to have four divers stay submerged for three weeks, conducting their undersea experiments at a depth of 193 feet of seawater (fsw) (58 m). After 11 days the experiment was halted due to an approaching tropical storm.

Aquanauts aboard SEALAB I at a depth of 192 feet below sea surface (U.S. Navy Photo by Barth, Qumc USN)

SEALAB II was a completely new habitat, 57 by 12 feet in size, and unlike SEALAB I included hot showers and refrigeration. It was placed in the La Jolla Canyon off the coast of California, at a depth of 205 fsw (62 m). On August 28, 1965, the first of three teams of divers moved into what became known as the “Tilton Hilton” because of the slope of the site. Each team spent 15 days in the habitat, but aquanaut/astronaut Scott Carpenter remained below for a record 30 days. During that time, he was able to speak with astronaut Gordon Cooper who was in the Gemini space capsule, orbiting the Earth. In addition to physiological testing, the divers tested new tools, methods of salvage, and an electrically heated drysuit. They were aided by Navy porpoise Tuffy, who ferried supplies from the surface.

SEALAB II

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” weren’t done in the open sea, but in a special hyperbaric chamber that could recreate the pressures at depths as great as 1,025 fsw.

On February 15, 1969, SEALAB III was lowered to 610 fsw (185 m), off San Clemente Island, CA. The habitat soon began to leak and divers were sent to repair it, but they were unsuccessful. Tragically, during the second attempt aquanaut Berry Cannon died. It was later found that his breathing apparatus was missing the chemical necessary to remove carbon dioxide. 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.

The SEALAB program proved the viability of saturation diving and humans living in isolation for extended periods of time. The knowledge gained helped advance the science of deep sea diving and rescue, and contributed to our understanding of the psychological and physiological strains humans can endure.