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A.J. Morse & Son 5 Bolt Antique Diving Helmet


A.J. Morse & Son 5 Bolt US Navy Mark 1 - Very Rare!

Incredibly rare factory original example of a 5 bolt diving helmet made by the A.J. Morse & Son Company in Boston, Massachusetts circa 1914. In addition to the very desirable 5 bolt configuration and original condition, this helmet fits all the criteria to be classified as a United States Navy Mark 1 helmet!

As shown in the photos above, this helmet is indeed in amazing original condition. It retains an incredible percentage of the factory-applied tinning, even after 106 years. The helmet is also complete and serial numbers matching. A.J. Morse would place the serial numbers on both neck rings and all four brails. This helmet has the same number in these locations, 1809.


All the original brass hardware is present including the wing nuts, window guards, neck ring bolts and wing nuts, exhaust, air & communications fitting as well as an A.J. Morse & Son Inc non-return valve. All of the glass is present and in excellent condition. New neck ring gasket has been installed. The internal bonnet air vents, as well as possibly the original wiring and communications equipment, are even intact! The bonnet only has a few very minor working dents. In our years of handling helmets, this is possibly the nicest all original and complete example we have had the opportunity to handle.

Five bolt helmets are inherently very difficult to find. They were originally more expensive than interrupted thread commercial helmets, by as much as 20% to 25%. The US Navy was probably the largest customer for this model. After the Mark V was introduced, many "bolt" helmets were then converted or modified into interrupted thread style by the US Navy. For this reason and simply age, only a very few of these original bolt helmets like this still exist. Their unique design, size, weight, and place in diving history make them prime investment pieces and prized pieces of any collection.


According to the 1916 US Navy Diving manual the following characteristics belong to the Mark I.

Bolt type; wide breastplate; screw faceplate; oval top and side windows; “Morse” type regulating escape valve, telephone, safety valve, and air inlet connection; manufactured by A.J. Morse & Son (Inc.), Boston, MASS.

While it not possible to determine if this helmet was in US Navy inventory, it does match the US Navy definition of a Mark 1 helmet. If you have ever considered owning a five-bolt or helmet or a Mark 1, without a doubt it will be unlikely you will ever have the opportunity to own a finer example.

The helmet will be accompanied by a certificate of authenticity from Nation's Attic Inc that will be serial-numbered to a tamper-proof hologram placed inside the helmet. Display stand as shown in photos sold separately.

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