The Secret Weapon of Navy Diving

By Mary Ryan, Curator, Naval Undersea Museum

The Navy has many unsung heroes; in fact, you could argue most of our Navy is made up of them. A central truth about unsung heroes, by the term’s very definition, is that their contributions are significant yet under-recognized. September 25th, the Naval Undersea Museum opens a new exhibit that shines a spotlight on one of the subsurface community’s unsung heroes: the Navy Experimental Diving Unit (NEDU).

NEDU significantly expanded the Navy's diving capabilities. Rebreathers, like this 1970s LAR III, allow Special Forces divers to operate undetected.

NEDU significantly expanded the Navy’s diving capabilities. Rebreathers, like this 1970s LAR III, allow Special Forces divers to operate undetected.

If this is the first you’re hearing about NEDU (pro tip: “NEDU” is one of the few Navy acronyms that isn’t pronounced as a word — it’s “N–E–D–U”), let me introduce you to Navy diving’s secret weapon. The scientists, engineers, and divers of NEDU not only keep Navy Divers, Special Forces divers, and Explosive Ordnance Disposal techs safe, they expand their diving capabilities. In practice, this means they research, develop, test, and certify diving equipment and procedures. Put it another way, NEDU personnel are essentially professional problem-solvers: they use their expertise and experience to find solutions for the challenges of working underwater.

NEDU was stationed at the Washington Navy Yard, where this 1974 photo was taken, for almost 50 years before moving to its current home in Panama City, Florida, in 1975.

NEDU was stationed at the Washington Navy Yard, where this 1974 photo was taken, for almost 50 years before moving to its current home in Panama City, Florida, in 1975.

NEDU has solved many diving problems since it was established in 1927. Most famously, it developed the decompression tables that remain the worldwide standard today, for military and recreational divers alike! Decompression tables tell divers how to safely decompress after a dive. (Why is that important to divers? Because failure to decompress safely is more than a minor annoyance, it can cause decompression sickness, a dangerous condition that can kill a diver if not treated successfully.) Divers use different types of decompression tables depending on how long and deep they dive, the type of breathing mixture they use, and the type of gear used, among other factors. Over the years, NEDU staff have developed or improved more than 20 different types of tables.

Off the coast of Cape Hatteras, N.C. (Jul. 27, 2002) -- Hospital Corpsman 1st Class David Keener (left) and Chief Hull Technician Brad Flemming breathe oxygen in a decompression chamber after returning from a 240 ft. dive operation conducted on the sunken civil war-era ironclad ship USS Monitor. The famed warship sank during a storm Dec. 31, 1862, off Cape Hatteras, N.C., while being towed to Beaufort, S.C. Four officers and 12 men were lost with the ship. U.S. Navy photo by PhotographerÕs Mate 1st Class Chadwick Vann. (RELEASED)

Off the coast of Cape Hatteras, N.C. (Jul. 27, 2002) — Hospital Corpsman 1st Class David Keener (left) and Chief Hull Technician Brad Flemming breathe oxygen in a decompression chamber after returning from a 240 ft. dive operation conducted on the sunken civil war-era ironclad ship USS Monitor. The famed warship sank during a storm Dec. 31, 1862, off Cape Hatteras, N.C., while being towed to Beaufort, S.C. Four officers and 12 men were lost with the ship. U.S. Navy photo by PhotographerÕs Mate 1st Class Chadwick Vann. (RELEASED)

At depths deeper than 165 feet, divers can begin experiencing a disorienting, drunk-like condition called nitrogen narcosis. NEDU fixed this problem in the 1930s by developing a new breathing mixture using helium. Replacing the nitrogen in air with helium removed the threat of nitrogen narcosis and allowed divers to – VIOLA! go deeper, safely. Today breathing helium remains the standard Navy practice for surface-supplied dives to 190 feet or greater.

Today NEDU spends most of its time testing new diving equipment and establishing diving procedures. Its exhaustive testing may not be the most glamorous of Navy projects (another truth of an unsung hero’s work) but it’s monumentally important. Our diving Navy is known for its uncompromising safety and unparalleled expertise, a reputation earned in part by the many hundreds of pieces of diving gear NEDU has tested and procedures it’s developed.

Delve further into these accomplishments and more in the Naval Undersea Museum’s new exhibit, “NEDU: Rising to the Challenge.”

 

Not in the Seattle area? Enjoy an online version of the exhibit here: http://www.navalunderseamuseum.org/nedu/.