Bathyscaphe Trieste

Dive to the deepest part of the ocean

Having invented a lighter-than-air balloon to ascend beyond the stratosphere, Swiss inventor Auguste Piccard then switched focus to the depths of the oceans. Only three men have reached the deepest part of the Challenger Deep at the bottom of the Marianas Trench. Two of them got there in Piccard’s Bathyscaphe Trieste.

Piccard applied his theories of buoyancy learned in balloon flight to the Trieste, a navigable titanium diving vessel, with an observation gondola of 5-inch-thick steel, weighing over 14 tons. Its ballast was a mixture of heptane, water, and 9 tons of iron pellets in tanks that allowed it to sink. Ballast was released to control buoyancy and to allow it to resurface. It was completed in 1953 and named for the city of Trieste in Italy, where it was built. The Navy bought the vessel in 1956 and upgraded the pressure sphere in 1959 to withstand pressure up to 36,000 feet.

US Navy Lt. Don Walsh volunteered to go on the expedition to Challenger Deep, but a second volunteer would not step forth. So Piccard recruited his son, oceanographer Jacques Piccard, to take the second seat.

On January 23, 1960 Trieste descended for 4.75 hours to 35,814 feet. Exploration only lasted 20 minutes, as a Plexiglas window had cracked on descent, causing the vessel to shudder. They observed a brown “diatomaceous ooze” and deep-water flounder and sole, unexpected vertebrates to find at that depth. There was no publicity until they returned, as Admiral Arleigh Burke wanted no embarrassments if they failed. Journalists sniffed out the story but agreed with the Navy not to publish until after the mission.

Trieste was replaced in 1963 with Trieste II and moved to the US Navy Museum. The dents from the pressure of the sea are visible in the ballast tanks.

The third explorer to reach Challenger Deep was James Cameron in 2012, though only to 35,787 feet.

Address US Navy Museum, Washington Navy Yard, 736 Sicard Street SE, Washington, DC 20003, +1 (202) 685-0589, www.history.navy.mil | Getting there Metro to Navy Yard-Ballpark (Green Line), walk east on M Street SE to 11th Street SE, turn right to Visitor Gate; bus 90, 92, P 6, V5 to 11th and O Streets SE; ID or passport required | Hours Mon – Fri 9am – 5pm, Sat & Sun 10am – 5pm | Tip Also in the museum, see scale models of early Naval ships, a captured Kamikaze training aircraft, and a model of Alvin, the submersible that helped locate RMS Titanic. Take a walk around the Navy Yard, the oldest continuously operating Naval base in the world.