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).
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 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.
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/.