The third in a series of limited production collectible “Helmets in History” challenge coins produced for and sold by the Historical Diving Society USA. Each coin in the series will highlight a diving helmet with a positive impact on deep sea diving.
Every coin produced has the original HDS logo of an Augustus Siebe helmet on one side and the featured “Helmets in History” helmet on the reverse. This coin features the U.S. Navy Mark V Helium helmet.
These collectible coins are 1.75″ in diameter, are highly detailed, and will be a prized possession for years to come. Each comes in a soft PVC envelope.
This coin features the “U.S. Navy’s Mark V Helium Helmet”. The development and use of this helmet came into focus with it’s use in the salvage of the US Navy’s submarine “Squalus (SS-192)” from a depth of 243 feet (74 meters) in 1939. Led by Commander Charles B. Momsen and Dr. A. R. Benhke, of the Navy’s Experimental Dive Unit (EDU), 648 dives, with only two cases of decompression sickness, led to successful salvage of the Squalus.