Human-occupied submersible makes historic dive by reaching a depth of 21,325 feet

The vessel, called Alvin, has unveiled the ocean’s mysteries.

Loukia Papadopoulos
Human-occupied submersible makes historic dive by reaching a depth of 21,325 feet
Alvin swimmers Molly Smith and Rick Sanger signal main latch release before deployment.WHOI

On Thursday, the human-occupied submersible Alvin made history when it successfully reached a whopping depth of 21,325 feet (6,453 meters), achieving the deepest dive ever in the 58-year history of the storied submersible, according to a press release by the Woods Hole Oceanographic Institution (WHOI). The event took place in the Puerto Rico Trench, north of San Juan, P.R.

A critical step to U.S. Navy certification

The dive was a key step to achieving certification from the U.S. Navy to resume operations after an 18-month break undertaken to overhaul and upgrade the sub’s maximum diving range from 14,800 feet (4,500 meters) to its new limit of 21,325 feet (6,500 meters). This process was conducted because Naval Sea Systems Command (NAVSEA) requirements stipulate the certification dive be between 6,200 and 6,500 meters.

“Investments in unique tools like Alvin accelerate scientific discovery at the frontier of knowledge,” said WHOI President and Director Peter de Menocal. “Alvin’s new ability to dive deeper than ever before will help us learn even more about the planet and bring us greater appreciation for what the ocean does for all of us every day.”

Alvin is one of the only deep submergence vessels in the world capable of carrying humans into such deep depths and conducting a scientific study of the ocean seafloor. Thursday’s dive means the sub has completed 5,086 successful dives, more than all other submersible programs in the world combined. 

Source: WHOI

On average, the vessel undertakes about 100 dives per year on missions to examine the processes that shape Earth’s crust, the conditions that enable life in extreme environments, and the significant diversity of life in the deep sea.

“For almost 60 years, the deep-submergence vehicle Alvin has unveiled the ocean’s mysteries—not just for military and national security purposes but also for the scientific benefit of society as a whole,” said Chief of Naval Research Rear Adm. Lorin C. Selby.

NAVSEA tests

For the past three weeks, Alvin further underwent a series of tests as part of its sea trials, overseen by the NAVSEA, which designs, builds, and maintains U.S. Navy ships and submarines. These included tests of its mechanical and electrical systems and its ability to operate safely at depth. The end result of these tests was permission to resume its operations and to dive to its new record-breaking maximum depth.

“Being able to work with the Woods Hole and ONR team to certify Alvin has been an honor for us,” said NAVSEA’s Commander Vice Adm. Bill Galinis. “At NAVSEA, we like to say we expand the Navy’s warfighting advantage, but with Alvin, we are now expanding scientists’ ability to learn more about inner space thanks to our world-class engineers and deep submergence expertise.”