In the Collection: Mark V Diving Helmet

By Nick Wieman
HRNM Volunteer

While humanity has been diving for thousands of years in search of food, pearls, and other treasures found on the sea floor, it wasn’t until the early 19th century when diving was no longer limited by the divers’ lung capacity or inflexibility of a diving bell. The invention and proliferation of reliable surface-supplied diving dress (diving suits with gases pumped from the surface) in the early 19th century revolutionized diving for commercial, scientific, and military purposes. While every seafaring nation had its own models of diving dress, the American Mark V diving dress would prove to be one of the most popular and recognizable models in the world, not just among divers but with the general public as well.

The US Navy had followed the lead of other navies in adopting diving suits in the mid-1800s, but until the early 1910s Navy divers were primarily utilized for underwater construction and repair of ships in harbor, with divers rarely going below 60 fsw (feet of seawater). With no standardized set of equipment, dives could become needlessly complicated by incompatible assortments from a wide range of commercial manufacturers. In 1912, Chief Gunner George D. Stillson established a program to test Scottish physician John Scott Haldane’s observations of stage decompression, with the broader goal of improving and professionalizing the US Navy’s diving program.

Stillson’s program yielded many firsts for the US Navy: the first official US Navy Diving Manual, published in 1916; the first official US Navy Diving School in Newport, Rhode Island (to be replaced by the Naval Diving and Salvage Training Center in 1941); and the deepest dive of any Navy diver yet, at 274 fsw. The program also introduced the first standard set of equipment for divers: the 1916 Mark V Diving Rig. Originally introduced in 1905 as a copy of the British Siebe-Gorman Davis Six Bolt Admiralty Pattern Helmet, the 1916 model implemented several key improvements, namely the telephone system and the “chin button” internal pressure regulator. Aside from small improvements in 1927 to reduce weight, and minor differences between manufacturers—Morse Diving Equipment Company and A. Schrader’s Son before WW2, additionally DESCO and the Miller Dunn Company after Pearl Harbor—the Mark V would remain unchanged as the standard diving system of the US Navy until the introduction of the Mark XII in 1984 and remains popular among commercial divers to this day.

Front view, Mark V diving helmet 

While scientific inquiry did its in part in furthering development of Navy diving, necessity has always been the mother of invention. The expansion of the Navy’s submarine fleets brought along with it a corresponding increase in submarine accidents, and an increased demand for skilled divers for rescue and salvage. The attack on Pearl Harbor signaled a new era for the Navy Diver; within an hour of the attack’s ending, divers were in the water, cutting open the capsized USS Oklahoma to rescue Sailors still trapped aboard the vessel, successfully rescuing 32 Sailors. Navy divers were crucial for the salvage and recovery efforts at Pearl Harbor, logging a cumulative 16,000 hours underwater and contributing to the successful salvage of 18 of the 21 ships lost or damaged during the attack; they would continue to play critical parts in salvaging both Allied and Axis shipwrecks throughout the course of the war. While not typically surface-supplied diving rigs, Navy divers in Construction Battalions (“Seabees”) were nevertheless crucial in building and maintaining the infrastructure necessary to conduct the island-hopping campaign in the Pacific.

U.S. Navy salvage unit clearing wreckage from Naples Harbor, October 22, 1943 (National Archives)

After the Second World War, surface-supplied diving continued its importance even with the advent of the Aqua-Lung and scuba systems in the late 1940s/early 1950s and the decline of dedicated naval salvage ships, becoming instrumental to several noteworthy scientific endeavors. Navy divers studied the wrecks of ships sunk during nuclear tests at Bikini Atoll during Operation Crossroads in 1946, carrying watertight Geiger counters that warned against radioactive hotspots. Navy Divers assisted in the recovery of the four hydrogen bombs lost off the coast of Palermos, Spain in 1966, alongside the DSV-2 Alvin submersible. Finally, US Navy divers were critical to the construction of several undersea research laboratories, including the three SEALAB and two Tektite projects; the latter Tektite projects led to the creation of the Seabees’ two dedicated Underwater Construction Teams.

Divers off USS Preserver preparing to do a visual survey of USS Saratoga at Bikini Atoll in 1947 (Lauren R. Donaldson collection, University of Washington)

This particular helmet in the Naval Museum’s collection is the Mark V Model 1 Diving Helmet, formerly owned by Lt. Albert J. Banasky. It measures roughly 20 inches in height from the upper viewport to the tip of the breastplate, 14 inches wide from either side viewport, 15 inches deep from the faceplate to the back of the helmet and weighs a solid 68 pounds of solid bronze and brass. The “bonnet,” or the part of the helmet that goes over the diver’s head, is a copper dome with four prominent glass viewports, roughly half an inch thick, covered by brass grills for protecting. The insignia on the breastplate reads, “US NAVY DIVING HELMET/MARK V-MOD.1/DIVING EQUIPMENT AND SALVAGE CO. INC /[MILWAUKEE WIS./1917/DATE 12 1 44/”. The helmet’s overall condition is good, exhibiting the greenish discoloration typical of bronze and brass due to prolonged oxidation, with only the insignia on the breastplate becoming more obscured.

Right side view of helmet

Running along the bottom of the helmet’s right side is the spring-loaded exhaust system, which regulated the air pressure within the diver’s suit. One spring automatically triggered when the internal pressure reached .5 pounds per square inch, or by the diver turning the external valve; another spring guarded against over pressurization. Both could be bypassed by a “chin button,” within the helmet, activated by the diver pressing against it with his chin (hence the name), opening the helmet for maximum air circulation. Air is expelled from the helmet through the exhaust port towards the back of the diver’s neck, which prevented bubbles from obscuring their vision.

Left side view of helmet

On the left side of the helmet is the aptly named spitcock, which allowed the diver to draw water into their helmet to spit on the viewport in case of fogging, or for blowing air out of the helmet to fine-tune air pressure. On the left side of the helmet’s back is the air inlet elbow, on the right the inlet for the telephone cable.

Divers wearing Mark V diving rig inter remains of USS Arizona survivor Lauren Bruner aboard the sunken Arizona, December 7, 2019 (Navy Times)

In one form or another, the Mark V has been a constant presence in the United States Navy since its introduction in 1916. While the Mark V may have been retired from active service in the United States Navy, it endures as a symbol of the diver’s heritage within the military. The Mark V features prominently in the insignia of the National Diving and Salvage Training Center, almost all diver insignias in the Navy, Marine Corps, and Coast Guard, and countless official and unofficial memorabilia relating to the Navy. More broadly, the Mark V has become the quintessential “diving suit,” an enduring symbol of undersea exploration and adventure in the popular consciousness.



Sources/Further Reading:
1. https://www.history.navy.mil/research/library/online-reading-room/title-list-alphabetically/d/diving-in-the-u-s-navy-a-brief-history.html
2. https://www.history.navy.mil/browse-by-topic/communities/divers.html
3. https://navalunderseamuseum.org/mk-v/
4. Raymer, Edward C. Descent into Darkness: Pearl Harbor, 1941—A Navy Diver’s Memoir. US Naval Institute Press. 2015