First Descent to the Deepest Part of the Deepest Ocean, 1960

Bathyscape (from US Naval Undersea Museum (DSV-1), Trieste

The year 1960 saw the culmination of a series of deep ocean submergence tests using small manned vessels near Guam in the western Pacific under the American navy’s Project Nekton.  On January 23, a bathyscaphe (BA-thi-skaf, “deep ship”) called the Trieste piloted by explorer USN Lieutenant Don Walsh and engineer oceanographer Jacques Piccard (son of the boat’s designer, Auguste Piccard) descended to the lowest part of the world’s oceans, the Mariana Trench, entering into a still lower valley cut out of the southern part of 1500-mile long trench called the Challenger Deep.  Named for the city where it was built in 1952, the French navy operated the Trieste in the Mediterranean Sea before the USN purchased it for undersea research in 1958 for $250,000.  The craft was about sixty feet long and weighted fifty tons.  It was retrofitted by Krupp Steel Works of Essen, Germany with a pressure compartment attached to the middle of the underside of the main hull, built of five-inch thick walls to withstand more than the anticipated 17,000 psi at maximum depth, and room for only two people.

The dramatic dive was effected by a variety of floats in the craft’s design and batteries powered onboard instruments.  Piccard and Walsh communicated with the support ship, the USS Wandank (ATA 204), through a sonar/hydrophone system.  It took almost 5 hours to reach the ocean floor at a rate of about 3 feet per second, and the journey was mechanically uneventful except for the cracking of one of the plexiglas windows which shook the craft at a depth of 10,000 yards.  The bathyscaphe recorded an astounding final depth of nearly 37,800 feet, a mile deeper than Mt. Everest is high, and rested there for just twenty minutes before the ascent to the surface that took a bit over 3 hours.

Relative Depths of Challenger Deep and Everest

The men carried no sophisticated scientific equipment and conducted no experiments.  They simply proved the dive could be done.

The lowest spot in the ocean floor, the Challenger Deep, was named for the British vessel, HMS Challenger, that first surveyed the area in the years 1872-76 and was said to catalogue over 4000 previously unknown species in its post-exploration report.  The expedition helped to lay the foundation of oceanography.  Keith Scott in The Australian Geographic Book of Antarctica (New South Wales, 1993) quotes the supervisor of the report, John Murray, as considering the Challenger voyage to have caused “the greatest advance in the knowledge of our planet since the celebrated discoveries of the 15th and 16th centuries” (Scott 193).  Walsh and Piccard continued this advancement of in knowledge of the Deep in their description of a sea floor covered with “diatomaceous ooze” and observed what resembled shrimp, and “flatfish” like flounder and sole — indeed, vertebrates living under the enormous weight of 6000 fathoms that no one thought possible before the Trieste dive.

The achievement of Piccard and Walsh would stand for 52 years.  Not until Canadian film director James Cameron’s 2012 solo dive to the bottom of the Trench in the Deep Sea Challenger would the manned voyage of the Trieste be repeated.

After this historic dive in 1960, the original Trieste was retired.  In 1963, however, the US Navy transported a rebuilt Trieste from San Diego through the Panama Canal to the New England coast to search for the remains of its most advanced attack submarine, Thresher (SSN 593) that sank east of Boston in April.  Search and recovery ships assisted by the Trieste found the remains of Thresher in six sections scattered over thousand of square yards of sea floor in 8400 feet of water.  The recovery operations exposed limitations in the navy’s deep submergence capabilities and led to the creation of the Deep Submergence Systems Project (DSSP).  Between the years 1965 and 1966, Auguste Piccard’s original Trieste underwent so many changes and redesigns that all that remained was the general shape of the vessel, which was christened Trieste II, the first of a new class for the Navy designated DSV-1 (“Deep Submersible Vessel”).  Trieste II saw service in the recovery of the attack submarine Scorpion (SSN-589) lost in 1968 west of the Azores and various CIA covert operations in the early 1970s. The Trieste class was replaced by the less-deep capable but more maneuverable Alvin class (DSV-2) of submersibles which used titanium in construction, saw thousands of research dives, and was operated by the Woods Hole Oceanographic Institution.  At the same time, Reynolds Aluminum and General Dynamics teamed up to build the world’s first aluminum research submarine, Aluminaut, used by the US Navy and marine biologists such as Jacques Cousteau.  Both were commissioned in 1964, and both famously helped find a 1.45-megaton atomic bomb lost in the western Mediterranean Sea during a training exercise by the the Air Force over Spain January 17, 1966.

For a marvelous first-hand scholarly account, see R.S. Dietz & Jacques Piccard, Seven miles down: the story of the Bathyscaph Trieste (New York: Putnam, 1961).  Dietz was a pioneer in confirming the idea of continental drift, and coined the phrase “seafloor spreading.”

See also recently published, Norman Polmar and Lee Mathers, Opening the Great Depths: The Bathyscaph Trieste and Pioneers of Undersea Exploration (Naval Institute Press, 2021).




Use image in Challenger Deep article (WIKI) of Mariana Trench map — licensure; black and white shot of Trieste I

Quote — about flatfish from Picard and Dietz (from same article)

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