The Bathysphere () was a unique spherical deep-sea submersible which was unpowered and lowered into the ocean on a cable, and was used to conduct a series of dives off the coast of Bermuda from 1930 to 1934. The Bathysphere was designed in 1928 and 1929 by the American engineer Otis Barton, to be used by the naturalist William Beebe for studying undersea wildlife. Beebe and Barton conducted dives in the Bathysphere together, marking the first time that a marine biologist observed deep-sea animals in their native environment. Their dives set several consecutive world records for the deepest dive ever performed by a human. The record set by the deepest of these, to a depth of on August 15, 1934, lasted until it was broken by Barton in 1949 in a vessel called Benthoscope.
Origin and design
In 1928, the American naturalist William Beebe was given permission by the British government to establish a research station on Nonsuch Island, Bermuda. Using this station, Beebe planned to conduct an in-depth study of the animals inhabiting an area of ocean, from a depth of to the surface. Although his initial plan called for him to conduct this study by means of helmet diving and dredging, Beebe soon realized that these methods were inadequate for gaining a detailed understanding of deep-sea animals, and began making plans to invent a way to observe them in their native habitat.
As of the late 1920s, the deepest humans could safely descend in diving helmets was several hundred feet.Cullen, Katherine E. Marine science: the people behind the science. New York: Infobase Publishing, 2006, . Submarines of the time had descended to a maximum of , but had no windows, making them useless for Beebe's goal of observing deep-sea animals. The deepest in the ocean that any human had descended at this point was wearing an armored suit, but these suits also made movement and observation extremely difficult. What Beebe hoped to create was a deep-sea vessel which both could descend to a much greater depth than any human had descended thus far, and also would enable him to clearly observe and document the deep ocean's wildlife.
Beebe's initial design called for a cylindrical vessel, and articles describing his plans were published in The New York Times. These articles caught the attention of the engineer Otis Barton, who had his own ambition to become a deep-sea explorer. Barton was certain that a cylinder would not be strong enough to withstand the pressure of the depths to which Beebe was planning to descend, and sent Beebe several letters proposing an alternative design to him. So many unqualified opportunists were attempting to join Beebe in his efforts that Beebe tended to ignore most of his mail, and Barton's first efforts to contact him were fruitless. A mutual friend of Barton's and Beebe's eventually arranged a meeting between the two, enabling Barton to present his design to Beebe in person. Beebe approved of Barton's design, and the two of them made a deal: Barton would pay for the vessel and all of the other equipment to go with it, while Beebe would pay for other expenses such as chartering a ship to raise and lower it, and as the owner of the vessel Barton would accompany Beebe on his dives in it.
Barton's design called for a spherical vessel, as a sphere is the best possible shape for resisting high pressure. The sphere had openings for three windows made of fused quartz, the strongest transparent material then available, as well as a entrance hatch which was to be bolted down before a descent. Initially only two of the windows were mounted on the sphere, and a steel plug was mounted in place of the third window. Oxygen was supplied from high-pressure cylinders carried inside the sphere, while pans of soda lime and calcium chloride were mounted inside the sphere's walls to absorb exhaled CO2 and moisture. Air was to be circulated past these trays by the Bathysphere's occupants using palm-leaf fans. The design was originally called a "tank," "bell," or "sphere". Beebe coined the name "bathysphere" using the prefix of the genus Bathytroctes.
The casting of the steel sphere was handled by Watson Stillman Hydraulic Machinery Company in Roselle, New Jersey, and the cord to raise and lower the sphere was provided by John A. Roebling's Sons Company. General Electric provided a lamp which would be mounted just inside one of the windows to illuminate animals outside the sphere, and Bell Laboratories provided a telephone system by which divers inside the sphere could communicate with the surface. The cables for the telephone and to provide electricity for the lamp were sealed inside a rubber hose, which entered the body of the Bathysphere through a stuffing box.
After the initial version of the sphere had been cast in June 1929, it was discovered that it was too heavy to be lifted by the winch which would be used to lower it into the ocean, requiring Barton to have the sphere melted and re-cast. The final, lighter design consisted of a hollow sphere of cast steel which was in diameter. Its weight was 2.25 tons above the water, although its buoyancy reduced this by 1.4 tons when it was submerged, and the of steel cable weighed an additional 1.35 tons.
History of use
The Bathysphere's first dives were conducted from the deck of a former British Naval ship called the Ready, which was towed by a tugboat called the Gladisfen. The winch used to raise and lower the sphere had been salvaged from a third ship, the Arcturus, on which Beebe had led two previous expeditions. One of Beebe's assistants, John Tee-Van, was in charge of operations aboard the two ships, while another, Gloria Hollister, had the duty of communicating with the two divers via the telephone line and taking notes of whatever observations they communicated to her.
1930–1931 Beebe and Barton conducted their first test of the sphere on May 27, 1930, descending to the relatively shallow depth of in order to ensure that everything worked properly. For a second test, they sent the Bathysphere down unmanned to a far greater depth, and found after pulling it up that the rubber hose carrying the electrical and phone cables had become twisted forty-five times around the cable suspending the Bathysphere. After a second unmanned test dive on June 6 in which the cord did not become tangled, Beebe and Barton performed their first deep dive in the Bathysphere, reaching a depth of 803 ft (245 m).
Beebe and Barton conducted several successful dives during the summer months of 1930, documenting deep-sea animals which had never before been seen in their native habitats. During these dives, Beebe became the first person to observe how as one descends into the depths of the ocean, some frequencies of sunlight disappear before others, so that below a certain depth the only colors of light that remain are violet and blue. Beebe and Barton also used the Bathysphere to perform shallower "contour dives", mapping Bermuda's underwater geography. These were particularly dangerous due to the possibility of the Bathysphere smashing against the underwater cliffs which Beebe was mapping, and Barton installed a rudder on the Bathysphere in order to better control its motion during these dives. On June 16, in honor of Hollister's 30th birthday, Beebe allowed her and Tee-Van to perform a dive in the Bathysphere to a depth of , setting a world record for a dive by a woman. Hollister and Tee-Van pleaded to be allowed to descend deeper than this, but Beebe did not allow it out of fear for their safety. In the fall of 1930 Barton donated the Bathysphere to the New York Zoological Society, the primary organization behind Beebe's work.
Beebe attempted to continue his dives in summer of 1931, but was foiled by technical problems and by the weather. The Arcturus winch developed a crack in it, a replacement for it did not arrive until the end of July, and by that time Bermuda was being plagued by storms which made the water too rough for dives to be conducted safely. The onset of the Great Depression also made it more difficult to obtain funding, and in an effort to raise money for continued dives Beebe promised to eventually descend . He also obtained more funds for his dives by writing an article describing them for the June 1931 issue of National Geographic titled "Round Trip to Davy Jones' Locker". Illustrations for the article were painted by Else Bostelmann, a wildlife artist who frequently illustrated the animals that Beebe observed during his dives.
1932 Beebe and Barton resumed their dives in 1932, this time launching the Bathysphere from a single ship called the Freedom instead of the Ready and the Gladisfen. They had arranged a plan with NBC whereby their observations relayed up the phone line would be broadcast nationally over the radio. Barton also hoped to film deep-sea creatures from inside the Bathysphere. Beebe normally observed the depths through one of the Bathysphere's three windows since the searchlight was shone through the second, and a steel plug had been in place of the third, but this was changed when Barton had the steel plug replaced with a third window in order to film through it. When conducting an unmanned test of the Bathysphere with the third window installed, they found it almost entirely full of water. Realizing the immense pressure that the Bathysphere must be under, Beebe ordered his crew to stand clear and began loosening the hatch's bolts to remove the hatch himself. Beebe described the experience that followed this in his book Half Mile Down:
Suddenly, without the slightest warning, the bolt was torn from our hands, and the mass of heavy metal shot across the deck like the shell from a gun. The trajectory was almost straight, and the brass bolt hurtled into the steel winch away across the deck and sheared a half-inch [13 mm] notch gouged out by the harder metal. This was followed by a solid cylinder of water, which slackened after a while into a cataract, pouring out the hole in the door, some air mingled with the water, looking like hot steam, instead of compressed air shooting through ice-cold water.
After replacing the third window with the steel plug and conducting another unmanned test, the same problem happened again. Beebe later described what would have happened to him and Barton had they been inside the sphere on a dive during which it leaked. They would not have had time to drown: due to the immense pressure, "the first few drops of water would have shot through flesh and bone like steel bullets."Osborn, Henry Fairfield Jr. "My Most Unforgettable Character". Reader's Digest, July 1968.
After packing the plug in more securely, and sending the Bathysphere down for another test dive in which the plug held, Beebe and Barton set off for their radio dive on September 22. The first part of the radio broadcast was conducted from on board the Freedom, describing Beebe and Barton preparing for their dive, while the second part would be relayed up the phone line from the sphere as Beebe and Barton descended in it. The ocean during this dive was rougher than it had been during any of their previous dives, and as the Freedom rocked on the surface, its motion was transmitted down the steel cable, causing the Bathysphere to swing from side to side like a pendulum. As the Bathysphere descended, Barton succumbed to seasickness and vomited inside it. However, the first half of the radio transmission had already been broadcast, and neither Beebe nor Barton wished to cancel its second half, so they continued their descent.