From the earliest times people have sought to explore the oceans. The sheer size of the ocean and its hidden depths fed human curiosity. Imagine scenes of life, known and unknown, which inhabit the vast ocean depths. These sights, combined with the need for new fuels and food, as well as a longing for adventure, led to undersea exploration.
While exciting, there are many problems people encountered when trying to explore the depths of the sea. Lack of oxygen, cold temperatures, water pressure, and darkness forced explorers to develop machines and equipment able to keep a human alive underwater. Their inventions have made undersea exploration possible.
Essential to the exploration of the deep waters was the development of instruments and ships that could withstand the pressure at hundreds of feet below sea level. In 1947 Swiss scientist August Piccard developed the bathyscaphe. Using a specially constructed steel diving sphere and a system for propulsion, Piccard created a vessel that traveled 4,600 feet into the ocean without being tied to a surface ship. Trieste, one of the first bathyscaphes, was built by Piccard in 1953 and transferred to the U.S. Navy in 1958. In January of 1960, August Piccard's son, Jaques, and U.S. Navy Lieutenant Don Walsh descended in Trieste to a depth of 35,800 feet. The dive took place in the Marianas Trench off the coast of Guam and was completed in about eight hours.
Trieste's ability to dive deep allowed the U.S. Navy to locate a lost submarine. In 1963 the nuclear submarine Thresher sank. Trieste located the wreckage, but it was not able to retrieve many of the pieces. This tragedy sped up the development of submersibles for rescue and exploration that were not as limited in function as bathyscaphes.
In 1964 Woods Hole Oceanographic Institution's Science Research Center built the small, maneuverable submersible Alvin. Able to carry a pilot and two scientists, this craft could reach a depth of 12,000 feet and was equipped with a maneuverable arm. In 1966 Alvin was called upon to retrieve an American hydrogen bomb lost in the Mediterranean Sea after a mid-air bomber collision. With the help of surface ships and other submersibles Alvin located the bomb and assisted in lifting it to the surface. Alvin was also used extensively to explore the ridges and vents of the oceans. These dives in the Pacific and Atlantic Oceans recorded new information about the conditions at these depths identified unknown plant and animal life. One of Alvin's most famous dives was to the wreckage of the cruise ship Titanic in 1986. In 1989, Alvin celebrated its 25th anniversary, as the world's most active research submersible.
A variety of manned submersibles are in use today. These vessels can carry two or three people and descend from 600 to 36,000 feet. These underwater vehicles also discover pieces of naval history, such as the wrecks of USS Monitor and CSS H.L. Hunley. As scientists learn more about oceans, that knowledge will broaden our understanding of the natural and historical resources below the surface.