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Nicknamed the “Widow Maker” by those brave enough to use it, the U.S. Navy Mark V helium diving helmet is an impressive piece of diving technology and a visually magnificent piece of history. Weighing more than one hundred pounds, the helmet was designed for extreme diving missions.

The Mark V helmet was used by the Navy from 1916 to 1984, when the fiberglass helmet took over. Starting in the 1930s, the need for deeper dives forced Mark V modifications. Using a large brass canister on the back containing a CO2 absorbent and a helium-oxygen mixture, divers outfitted in a Widow Maker could work at depths past the 100 to 150-foot limit of a standard helmet. Typically, those missions were either submarine rescues or salvage jobs and exceptionally dangerous, thus the helmet’s nickname.

Mark V helium helmet

A 1971 Mark V helium helmet from the Morse Diving Equipment Co., Boston, sold for $20,400 at auction.

Because of their cost, advanced training required for use, and the limited number of missions requiring such a helmet, few Mark V mixed gas helmets were made. Fewer yet survive.

This 1971 Mark V helium helmet was ordered by the Navy from the Morse Diving Equipment Co., Boston. “This helmet is probably the finest example of an original, completely unaltered helium Mark V we have ever handled or seen,” said Don Creekmore, of Nation’s Attic, in Wichita, Kansas, one of the leading businesses specializing in the buying and selling of antique diving equipment. Including fees, the helmet recently sold for $20,400 at auction.

USS Squalus

The USS Squalus back from the deep 113 days after sinking off the New Hampshire shore. Berthing of the submarine was a triumphant climax of one of the toughest salvage jobs ever tackled by the Navy.

Arguably the most dangerous and courageous rescue in Naval history involved the then experimental Mark V helium helmet. On May 23, 1939, the USS Squalus slipped beneath the storm-tossed surface of the Atlantic Ocean during routine sea trials. Moments later its main engine air induction valve failed, and water poured uncontrollably into the submarine’s aft engine room. The 310-foot Squalus sank to the ocean floor nine miles off the New Hampshire coast, trapping 59 men.

Successful submarine rescues were rare. Since 1921, 825 men had died in submarine accidents. No rescue attempt had ever succeeded in more than 20 feet of water. The Squalus was down 240 feet.

A hastily assembled Navy team had no choice but to use new, experimental diving methods that fed divers a mixture of helium and oxygen to avoid decompression sickness, or the bends, associated with such depths. Until that moment, those diving methods existed in theory only.

Squalus submarine rescue

An original artist's detailed sketch of the Squalus resting on the ocean floor 240 feet below the surface while the 59 men aboard await rescue. 

Twenty-six crewmen died on the Squalus, but 33 were rescued during a 39-hour ordeal in one of the most daring and riveting rescues in naval history. In the end, the officers and men of the Squalus rescue and salvage teams received four Medals of Honor, 46 Navy Crosses and one Distinguished Service Medal. While there were countless tears shed in the homes of those who didn’t survive the horrific accident, a glorious new chapter was written in the history of underwater rescue.

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