Navy Conducts Expeditions Summary

  • Last updated on November 10, 2022

Undersea living and working began with the Sealab expeditions of the early 1960’s, marking the first time humans lived below the ocean’s surface for an extended time period. The success of Sealab II, which placed team members in an underwater chamber for fifteen days—and their commander for thirty days—set the stage for more ambitious human exploration of the oceans.

Summary of Event

In the late 1950’s and early 1960’s, it became clear that the oceans of the world were critical to the well-being of life on Earth. Not only was there a rise in the study of the oceans for scientific reasons (the increased popularity of oceanographic studies, for example) but also, increasingly, the ocean was considered the next frontier to be explored and possibly exploited for its wealth of resources. Those resources, both food and minerals, lay locked beneath a layer of water, which made both exploration and exploitation extremely difficult. Sealab expeditions Deep Submergence Systems Project Exploration, underwater [kw]Navy Conducts Sealab Expeditions (July 20, 1964-Oct., 1965) [kw]Sealab Expeditions, Navy Conducts (July 20, 1964-Oct., 1965) Sealab expeditions Deep Submergence Systems Project Exploration, underwater [g]North America;July 20, 1964-Oct., 1965: Navy Conducts Sealab Expeditions[08130] [g]United States;July 20, 1964-Oct., 1965: Navy Conducts Sealab Expeditions[08130] [c]Exploration and discovery;July 20, 1964-Oct., 1965: Navy Conducts Sealab Expeditions[08130] [c]Science and technology;July 20, 1964-Oct., 1965: Navy Conducts Sealab Expeditions[08130] [c]Earth science;July 20, 1964-Oct., 1965: Navy Conducts Sealab Expeditions[08130] [c]Health and medicine;July 20, 1964-Oct., 1965: Navy Conducts Sealab Expeditions[08130] Link, Edwin Albert Cousteau, Jacques Carpenter, M. Scott

Prior to this time, ocean exploration occurred almost exclusively by remote means. Scientists working from surface ships used nets, dropped from the surface, to scoop up marine animals, marine plants, and surface minerals. Individual divers also descended from surface ships, encased in metal hard-hat, wearing lead-weighted boots, and tethered to the ship by breathing hoses. Although they were able to make direct observations and take samples, their mobility was limited.

There came a major advance in direct, human exploration of the oceans when the first self-contained underwater breathing apparatus (scuba) Scuba diving was invented and perfected in the mid-1940’s by Jacques Cousteau. The perception that humans were now completely free to explore the oceans led some enthusiasts to envision human colonization of the relatively shallow (less than 650 feet deep) continental shelves surrounding many continents. Coincidentally, the continental shelves were, and continue to be, the most productive areas of the ocean and the focus of most mineral (particularly oil and gas) exploration.

Before those dreams could be realized, however, it remained to be seen if the problems and dangers associated with undersea living and working could be overcome. Almost all the anticipated difficulties were related to medical problems associated with extended periods of living and working in an oceanic atmosphere. Ocean water is considerably denser than air. Thus, performing a simple task in the ocean requires more expense of energy, and perhaps more time, than on land. Work schedules in the ocean would have to consider diver exhaustion and provide for adequate rest or more shifts of divers.

Even more dangerous was the realization that a diver, living and working in the ocean for longer than a day, could not return easily to the surface. Breathing air under pressure saturates the body tissues quickly with gases in the air such as nitrogen. Removing those gases from the tissues, however, must be done by slowly decreasing the pressure (decompressing) over many hours (around eighteen) so bubbles do not form in the blood vessels. If the pressure is decreased too quickly and bubbles form, they can cause severe pain (the bends), paralysis, and death. In the late 1950’s, U.S. Navy medical doctors designed a series of experiments, using animals and volunteer Navy divers, to test the physiological and psychological effects of extended exposure to pressures that simulated deep dives. At the same time, Edwin Albert Link was experimenting with the equipment necessary to house a diver in the ocean and return the diver to the surface for decompression. The results of these efforts laid the foundation for the Navy’s efforts in saturation diving.

Sealab I, completed in 1964, proved that the results obtained in the controlled experiments on land could be translated successfully to the ocean. In Sealab I, four divers spent eleven days living and working 193 feet below the surface near Bermuda beginning on July 20. The experiment was halted, however, because of an approaching tropical storm.

Sealab II was the next step in the process of maintaining working communities in the sea. Unlike the ideal conditions of clear, warm water experienced in Sealab I, Sealab II—50 feet in length and 12 feet in diameter—was to be located in the cold, dark waters of the Pacific off the coast of La Jolla, California. The Southern California location provided access not only to ocean conditions that are more typical of the environment but also to the research base provided by proximity to the oceanographic research facilities of the Scripps Institute of Oceanography.





One objective of the project was to evaluate the general ability of divers to function and do useful work in a realistic ocean environment, at 205 feet below the surface, under saturation diving conditions. Further, observers were interested in the physiological and psychological effects of living for extended periods of time at that depth. The living quarters were spartan and crowded, which only added to an already stressful situation. The first of three teams of divers occupied Sealab II on August 28, 1965. Each team member spent about fifteen days working in and around Sealab. Commander M. Scott Carpenter, the leader of teams one and two, spent thirty days below the surface.

The teams were composed of mostly Navy divers with a few civilians with oceanographic backgrounds in each team. All team members were monitored to obtain medical and psychological data. In addition, all team members were involved in evaluating underwater equipment (for example, novel breathing equipment and heated diving suits) and tools (for example, tools used in salvage operations). They were required to perform certain group tasks (for example, assembling at a certain location after a signal), and the time required to perform the task was compared with that required on land. Some of the divers collected data on fish behavior and collected samples for fish physiology studies. One group tested the utility of trained dolphins as aids to working divers. Another group tested various methods, including underwater drilling, to obtain geological samples.

At the end of each team’s dive, they left Sealab and, while still underwater, entered a Personnel Transfer Capsule that maintained the same internal pressure as the divers experienced in Sealab. The team was raised to the surface while in the capsule and immediately transferred to the more spacious decompression chamber on the deck of the support ship. There the divers underwent the slow (approximately thirty-hour) process of decompression (slowly equilibrating their blood gases to earth surface pressure) in order to return safely to normal life on the surface.

The results of the experiments were, in general, positive. While it was well known that tasks performed underwater take longer than the same tasks performed on land, the magnitude of the delay was not known. Also, the psychological effects of having difficulties performing otherwise simple tasks did not seem to be very adverse. Team morale remained high despite the difficulties.

The heated diving suits were successfully tested in the hope that they would relieve the divers from expending so much of their energy simply trying to maintain body heat in the cold waters of the Pacific. In addition to cold water sapping the energy from a diver, the energy required to perform tasks in the water is greater than on land. Simply moving one’s hand or leg through water takes more effort than moving through air because water is a much denser (that is, thicker) fluid than air. Working in the ocean, therefore, requires divers to consume prodigious amounts of food merely to generate heat and overcome the fluid density difference when working.

The results of the biological and geological collecting efforts were more important because they took place rather than for the information they generated. It proved that scientists, not necessarily professional divers, could work and collect data successfully through saturation diving techniques.


Navy Commander M. Scott Carpenter aboard SEALAB II.

(U.S. Navy)

By the end of the Sealab II experiments in October, 1965, the Navy was convinced that there were very few impediments to having divers work for extended periods of time in the ocean. Obviously, there would have to be considerable safety measures in place before such an expedition. The experience gained in the Sealab projects, however, proved that the technology and knowledge were ready to support such an effort. Perhaps more important was the inclusion in the dive teams of civilian scientists.

Furthermore, there were specific scientific studies performed by team members during their period of saturation. These were important steps in moving saturation diving from the realms of medical experimentation and record-breaking headlines (for example, records for longest and deepest saturation dives) into the realm of a practical tool for scientific investigation of the ocean. It was now possible for scientists studying oceanic processes (for example, fish behavior, sediment movement, coral reef ecology) to spend extended periods of time in close contact with their study area through saturation diving techniques. The scientists who were interested in a saturation diving experience were not restricted from participation because of rigorous requirements. If a scientist had a well-defined scientific need, was reasonably healthy, and was a knowledgeable scuba diver, then participation in subsequent saturation diving programs was permitted.

As a result of programs building on the Sealab experience, such as the Hydrolab programs in the Bahamas and U.S. Virgin Islands, an increasing number of scientists have been trained in, and experienced, the science of saturation diving. In addition to training a cadre of scientists in the use of saturation diving, the programs have also trained a large number of support personnel, from medical doctors and nurses to marine engineers and mechanics, in routine and emergency shore-based operations. A wealth of experienced divers coming from the saturation diving programs was available when the off-shore oil drilling boom created a demand for divers capable of performing grueling tasks under adverse conditions. In addition, the medical knowledge from the saturation diving programs made it possible for this new service industry to perform tasks safely.

One of the advantages of the development of medical support personnel has come in a subsequent increased use of hyperbaric (high-pressure) medicine. Data from the studies performed by the Navy, coupled with the increased exposure of nonmilitary medical personnel to hyperbaric chamber operations through the Sealab and subsequent programs, spilled over into expansion of hyperbaric treatment through mainstream hospitals.

In the end, Sealab was both encouraging and sobering. Encouragement came from the fact that the complex operation was accomplished and most of the objectives were met. Divers can (and do) work productively in the ocean for extended periods of time. The sobering facts, though, are that the technical support required to mount such an expedition is formidable and the ocean is quick to punish mistakes or miscalculations. It became obvious that the underwater communities of the visionaries were still far in the future. Nevertheless, the reality of living and working in the ocean was within reach. Sealab expeditions Deep Submergence Systems Project Exploration, underwater

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Barth, Bob. Sea Dwellers: The Humor, Drama, and Tragedy of the U.S. Navy SEALAB Programs. Houston, Tex.: Doyle, 2000. A look at the Sealab project, including the final expedition in 1969, which ended in the death of one team member. Includes a foreword by Sealab commander M. Scott Carpenter.
  • citation-type="booksimple"

    xlink:type="simple">Cousteau, Jacques. Man Re-enters the Sea. New York: H. N. Abrams, 1975. A well-illustrated account of human adventures in the ocean from the perspective of the inventor of the scuba equipment that made it possible. In sections devoted to undersea habitats, Cousteau focuses on his own programs (Conshelf) but puts them into perspective by providing highlights of other programs (notably those of the U.S. Navy). Comprehensive index.
  • citation-type="booksimple"

    xlink:type="simple">Cousteau, Jacques, with Frédéric Dumas. The Silent World. Reprint. Washington, D.C.: National Geographic Society, 2004. An engaging book, made into a motion picture in 1956. Recounts many of the underwater adventures and explorations of Cousteau and his colleagues from 1938, including development of the Aqualung, or scuba.
  • citation-type="booksimple"

    xlink:type="simple">Earle, Sylvia A., and Al Giddings. Exploring the Deep Frontier. Washington, D.C.: National Geographic Society, 1980. A profusely illustrated volume that covers much of the history of human ocean exploration. There are numerous references and illustrations of undersea habitats, including Sealabs I and II. Index, good graphics, list of additional readings.
  • citation-type="booksimple"

    xlink:type="simple">MacInnis, Joseph B. “Living Under the Sea.” Scientific American 214 (March, 1966): 24-33. A good summary of the worldwide efforts to explore ocean dwelling from the pioneering work of Link to Cousteau and Sealab II. The level of discussion is easily accessible to high school students. Well illustrated with photographs and graphics.
  • citation-type="booksimple"

    xlink:type="simple">Marx, Robert F. Into the Deep: The History of Man’s Underwater Exploration. New York: Van Nostrand Reinhold, 1978. A comprehensive history of human attempts to explore the ocean’s subsurface environments. The last chapter focuses on the history of undersea habitats. Brief list of additional readings, index.
  • citation-type="booksimple"

    xlink:type="simple">Pauli, D. C., and G. P. Clapper, eds. Project Sealab Report: An Experimental 45-Day Undersea Saturation Dive at 205 Feet. Washington, D.C.: Government Printing Office, 1967. The official summary report of the Sealab II project produced by the Navy. Provides overviews and reports.
  • citation-type="booksimple"

    xlink:type="simple">Ross, Frank, Jr. Undersea Vehicles and Habitats: The Peaceful Uses of the Ocean. New York: Thomas Y. Crowell, 1970. A good focused narrative history of diving vehicles and underwater habitats. There is an interesting last chapter on the likely vehicles and habitats of the twenty-first century. List of suggested further readings, index.
  • citation-type="booksimple"

    xlink:type="simple">U.S. Navy. Office of Naval Research. Naval Forces Under the Sea: A Look Back, a Look Ahead. Flagstaff, Ariz.: Best, 2002. Report of the Naval Forces Under the Sea Symposium in Annapolis, Maryland in 2001. Discusses the history of naval research, the Sealab expeditions, and saturation diving, among other topics.

Cousteau and Gagnan Develop the Aqualung

Hillary and Tenzing Reach the Top of Mount Everest

Heezen and Ewing Discover the Midoceanic Ridge

Glomar Challenger Begins Collecting Ocean-Floor Samples

Categories: History Content