A great number of submersibles have been built over the years for the purpose of oceanographic research. However, with over 50% of the world's oceans reaching depths beyond 2000 metres, researchers were severely limited in what and where they could study in the oceans. It wasn't until the advent of a vessel capable of travelling to depths measured in thousands of meters that submersibles became viable oceanographic tools.
Early Deep-diving Submersibles
The first vessel capable of four-digit depth did little more than go up and down in the water column. As a matter of fact, the only other thing the bathysphere did was keep its inhabitants safe and (mostly) dry. Ultimately the passengers, Dr William Beebe and Otis Barton, would reach a depth of 923 metres. A major feat for 1934, it would prove to be the dawn of a new era for submersible research. The challenges of deep ocean research remained though, and only a rare few have overcome the complexities of deep-diving. To this day, over 60 years later, there is still only a handful of submersibles that have ever been capable of passing 1000 metres. Only one, the Trieste, has ever managed to reach absolute bottom. That milestone was reached in Challenger Deep in the Mariana Trench1, in 1960, when she landed at 10,910 metres.
A New Era For Submersibles
Over the years there have been numerous significant additions to the submarine community. One such submersible was the Aluminaut. Built by the Electric Boat Division of General Dynamics2, she supported the largest crew of any true research vessel with a complement of seven. For the most part, she spent her service life collecting minerals from among the sediments. She gained a second life when called upon several times to perform search and recovery missions. The first such mission came in 1966 when a collision between an Air Force KC-135 tanker and a B-52 bomber sent a nuclear warhead into the Mediterranean off the coast of Spain. Several submersibles were involved in the search, including the Alvin, at the time operated by the Office of Naval Research. Ultimately the Alvin would find the warhead but, due to its small size, could not recover it (an unmanned vehicle, the Curv, would make the actual recovery). In an odd twist of fate, in 1969, the Aluminaut recovered the lost Alvin in a joint project with the Naval Research Lab's Mizar.
Truly the most prolific of the deep ocean research vessels, the Alvin's early work was greatly overshadowed by her work after her recovery. By the time of her loss and salvage, Alvin was being operated by Wood's Hole Oceanographic Institute (WHOI). After the salvage, Alvin was used for a number of new experiments. Many of these stemmed from the questions revolving around her having sat on the bottom for ten months. It was found, for instance, that deep ocean benthic organisms (specifically bacteria) had a phenomenally slow metabolism. Eventually projects and funding for Alvin became increasingly sporadic. Visibility became a hot-button issue among the Alvin Group at WHOI. In 1977 Alvin came across something that would end the Group's fears about exposure and funding.
While on a routine dive to search for hydrothermal vents, the crew came upon something that astounded them. In an area off the Galapagos Islands massive concentrations of living organisms were found at depths too great to support photosynthetic life. Not only did the expedition prove the existence of hydrothermal vents, it also uncovered a number of brand-new species. Unfortunately, because it was on a geology-chemistry cruise, they lacked the proper materials for storing biological specimens. WHOI managed to wrangle finances the following year for a return trip, and in January 1979 Alvin went back to 9 North, this time specifically to collect organic specimens.
One other event raised the public's awareness of WHOI and Alvin. The event would be the discovery of the Titanic. Originally joked about by Bob Ballard, at a time when the Alvin Group was trying to justify operation of a deep-diving submarine, the idea would remain in the back of Ballard's mind until the mid-80s. At that time Ballard received funding from the US Navy and finagled his way past the Wood's Hole peer review to gain usage of Alvin for the task. Having found the Titanic through other means, it was Ballard's intention to actually visit her in the Alvin. The discovery was made on the first of September 1985, and shortly thereafter Ballard fulfilled a lifelong dream by actually looking upon the sunken ship with his own eyes. His discovery would open the world's eyes to the work of Alvin and other deep-diving vessels like her.
Where the world of undersea exploration and research will go from here is uncertain. A great emphasis has been placed on the development and use of ROVs (Remotely Operated Vehicles) for oceanographic work, but surely there must exist a place for manned submersibles in oceanography. Perhaps Graham Hawkes' series of Deep Flight vehicles represent the future, but that remains to be seen. In any case subs are sure to remain among our oceanographic tools for years to come.