@tbone1004
I am certainly not an expert but perhaps I can provide some insight as to the use of a concave bottomed HP cylinders in the world of SCUBA diving
In the 1940s to the 1950s concave bottomed HP cylinders were very common in the US amd used a diving tanks in California - were recreational diving began- for a number of years.
In California in the genesis of SCUBA diving. aka "Lung diving" at that time, professional scuba cylinders were considered expensive.
An alternative was to acquire cylinders from the surplus market such as the concave bottom fire extinguisher. Remove the valve and replace with an official J, K or R
or a US government surplus oxygen valve modified to fit by the late great Charlie Sturgil (google Charlie- or read "The Mask" on this board for additional historical knowledge
Acquire an Hawaiian Hydro and presto ! a SCUBA cylinder was born ready and waiting to be dove
The above is only my recollection perhaps
@herman can verify that it really did occur
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@EireDiver606
I have reviewed the 200 page German catalog
" Dre Tauchsportberater for 1967/1968 published by the HoZe ( Horst- Siegfried Zeller )
Although in German it has a multitude of pictures and illustrations and includes about every equipment manufacturer's in the world and ther products and is considered by many as The catalog for all diving equipment manufactured and marketed in US and Europe
The SCUBA cylinders are and photographed in detail listed on page 34 &35. All SCUBA cylinders are round bottomed ,
No flat or bump bottomed SCUBA cylinders
However diving has progressed a long way since 1960s and their are more manufactures suppling cylinders to day so there is the possibility of round bottom, con cave and bump bottom cylinders in the market place today,
Once again I would suggest the
@herman review his sources to verify my findings
Cheers
Sam Miller, III
(FYI-
@EireDiver606 The Fighting Irish won their 11 strait football game !!! ! )