USN diver tanks, big about 80 or 90 cu. ft. with a welded plug in the bottom.

[Luis H]

John there are many errors in your statements, but I don't have time to go over all of them now.

Just to give you an example. This statement below is totally incorrect. This is an absurd statement.

They were never built to be hydrostatically tested.

SeaRat

This cylinders were built to MIL-C-24316A. The Mil standard is very explicit about the cylinder requirements, including all the testing procedures. This cylinders were actually built and tested to a more stringent requirements that most ICC/DOT cylinders.


Here are two paragraphs from MIL-C-24316A.

4.4.3 Hydrostatic test. Each cylinder in the lot shall be hydrostatically tested to 5000 psi by the water jacket method of CGA Pamphlet C-1. The total volumetric, elastic and permanent expansions shall be determined in accordance with 3.2.7. Cylinders that leak or fail to meet these requirements shall be rejected.

3.2.7 Expansion characteristics. When hydrostatically tested to 5000 psi, the cylinder shall exhibit a total volumetric expansion of 65 +/- 7 cubic centimeters. The permanent expansion (PE) shall not exceed 5 percent of the total volumetric expansion, the remainder to be elastic expansion (EE).

Even the hydrostatic test pressure is stamped on the neck of these cylinders (per the Mil spec).

 

[captain]

Not only do they have the test pressure they have the original test results, elastic expansion, permanent expansion and the rejection limit and internal volume stamped on them.

 

[John C. Ratliff]

John there are many errors in your statements, but I don't have time to go over all of them now.

Just to give you an example. This statement below is totally incorrect. This is an absurd statement.

They were never built to be hydrostatically tested.

SeaRat

This cylinders were built to MIL-C-24316A. The Mil standard is very explicit about the cylinder requirements, including all the testing procedures. This cylinders were actually built and tested to a more stringent requirements that most ICC/DOT cylinders.


Here are two paragraphs from MIL-C-24316A.

4.4.3 Hydrostatic test. Each cylinder in the lot shall be hydrostatically tested to 5000 psi by the water jacket method of CGA Pamphlet C-1. The total volumetric, elastic and permanent expansions shall be determined in accordance with 3.2.7. Cylinders that leak or fail to meet these requirements shall be rejected.

3.2.7 Expansion characteristics. When hydrostatically tested to 5000 psi, the cylinder shall exhibit a total volumetric expansion of 65 +/- 7 cubic centimeters. The permanent expansion (PE) shall not exceed 5 percent of the total volumetric expansion, the remainder to be elastic expansion (EE).

Even the hydrostatic test pressure is stamped on the neck of these cylinders (per the Mil spec).

Luis,

According to this site, that standard, MIL-C-24316A was published first in 1971. I was using these cylinders in 1967. At this site, it states:

MIL MIL-C-24316A

CYLINDER, COMPRESSED GAS, DIVER'S, FOR DEMAND OPEN CIRCUIT SCUBA (NO S/S DOCUMENT) (SUPERSEDING MIL-C-24316)

STANDARD published 09/01/1971 by Military Specifications and Standards

When I look up the referenced standard, it also was published in 1971.

MIL MIL-C-24316A

CYLINDER, COMPRESSED GAS, DIVER'S, FOR DEMAND OPEN CIRCUIT SCUBA (NO S/S DOCUMENT) (SUPERSEDING MIL-C-24316)

STANDARD published 09/01/1971 by Military Specifications and Standards

The statements I made in those letters were not from me, but from the U.S. Naval School for Underwater Swimmers and from U.S. Divers Company. Do you have a more appropriately dated standard?

John

 

[Doubler]

Go Green Wave!

 

[John C. Ratliff]

Luis,

We have had this conversation before.
FS: Vintage Navy Scuba Tanks | Vintage Scuba Diving Community Forum

Here is Bill High's explanation from PSI-PCI:

By the mid 1950s, PST and perhaps one other company began making aluminum, cylinders from 6061 alloy for the US Navy. The fabrication process was very different from the way aluminum cylinders are made today. Although many of those round bottom aluminum cylinders found their way into civilian service, they are illegal for most purposes because they have no DOT designation. Those cylinders must not be hydrostatic retested and should not be filled at commercial air stations. WARNING-there are no legal round or semi-round aluminum scuba cylinders. Even though many of the old US Navy and Kaiser (SP6576) cylinders are used today, they are illegally retested by careless retesters and filled by unknowing fill station operators.

Read more: https://www.psicylinders.com/inspectors/library/74-briefscubacylinderhistory

SeaRat

 

[captain]

The plug is clearly visible from the inside, not so much from the outside.

 

[dead dog]

In early 1979, as a Safety and Health Consultant for the State Accident Insurance Fund, I was asked about these cylinders. I contacted U.S. Divers Company, and interviewed Mr. Grady Ford. He stated that these cylinders had a "tendency to blow up," used "old technology," were "spun cylinders with a plug," had "some instances of failure," and were of a "different alloy" (from my notes). I also contacted the U.S. Navy School for Underwater Swimmers (San Diego, California) and talked to an officer there. He stated that these tanks were associated with "Excessive bacteriology in the tanks," which had to do with a "fungus" and "bad air." They had to be "Rolled every time prior to filling." He also stated that it was "Probably a violation of contract to resell the cylinders." He asked that I "Get purchase order, write them and ask why the Navy got rid of the cylinders." (Again, from my notes from 1979.)

I also called Aquarius Underwater Center in Portland, Oregon (since has gone out of business). They stated that these cylinders "Cannot be hydroed (against the law)," and "Legally cannot be filled." (Again, from my 1979 notes.)

I am presenting the two letters, along with my "Record of Calls" (with names from the school removed). It may be hard to decipher my writing, so here is what I had to say about the calls to this school:

It is still my professional opinion that these cylinders should not be used as pressure vessels. My recommendation for this firm remains the same today, that they should be drilled in the plug, and used only for display.

John C. Ratliff, CSP, CIH, MSPH
"SeaRat"

John, if you or anyone else have two of these tanks I will still buy them, drilled or not drilled I don't care because there is NO law to own them. They were sold by the Government as surplus and that makes them legal. What you do with them may be a different story. They will be used for display. I'm thinking of making the Captain " an offer he can't refuse " ( The Godfather ) lol
As I stated before I need these tanks for a display and any help will be fully appreciated as well as paid.

Bill

 

[John C. Ratliff]

Dead dog,

I'll give you a PM with the name of the school involved, and you can call and ask for their welding shop teacher. They had over 300 of these cylinders, but that was in 1979. It is possible that they still have a few of the cylinders.

SeaRat

 

[scubaho]

If the price is right, I might sell 1 of my sets. pm sent

 

[dead dog]

Still looking for these ( USN Tanks ) if you have two for sale please contact me by IM.
These tanks can NOT be used for diving refills at dive stores, so they can't be worth a small fortune like some people think. I will pay fair prices you see on ebay for tanks.