Vintage Tanks
- Thread starter lonestardiver
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Those are Nave non-magnetic aluminum tanks. They were custom made from 6061-T6 aluminum tube for the Navy. They were made by PST (Pressed Steel Tanks). Those ones were made on 9/ 1967
They ends of the tube were spun shot and at the bottom there is an aluminum plug that was formed as part of the tank to close them off. The plug may not be visible from the out side. On many of these old tanks the plug tends to leak.
The tanks are not DOT approved (or stamped) so they can not be legally tested for use as a DOT tank. Most hydro stations will not (and maybe should not) test them. If they test it they can only stamp the date not their DOT ID number.
Structurally they are probably perfectly good tanks if they are not leaking from the plug and pass a hydro test. The hydro test would also detect any leaks.
A few divers are using them, if you have your own compressor, but I would strongly recommend having them hydro tested before putting compress air in them.
Since they are spun tanks, I would also perform a very detail visual inspection of the neck and bottom areas to look for cracks (and maybe even eddy current inspection of the neck). Cracks may be present without showing up in the hydro test results, therefore a detail visual inspection imperative.
I think the tanks are 90 cu ft each and I believe the Navy only used them in double sets.
The Navy needed for non magnetic tanks for dealing with magnetic mines long before aluminum tanks were commercially available for Scuba.
These are at least great collector tanks. They are rare.
They ends of the tube were spun shot and at the bottom there is an aluminum plug that was formed as part of the tank to close them off. The plug may not be visible from the out side. On many of these old tanks the plug tends to leak.
The tanks are not DOT approved (or stamped) so they can not be legally tested for use as a DOT tank. Most hydro stations will not (and maybe should not) test them. If they test it they can only stamp the date not their DOT ID number.
Structurally they are probably perfectly good tanks if they are not leaking from the plug and pass a hydro test. The hydro test would also detect any leaks.
A few divers are using them, if you have your own compressor, but I would strongly recommend having them hydro tested before putting compress air in them.
Since they are spun tanks, I would also perform a very detail visual inspection of the neck and bottom areas to look for cracks (and maybe even eddy current inspection of the neck). Cracks may be present without showing up in the hydro test results, therefore a detail visual inspection imperative.
I think the tanks are 90 cu ft each and I believe the Navy only used them in double sets.
The Navy needed for non magnetic tanks for dealing with magnetic mines long before aluminum tanks were commercially available for Scuba.
These are at least great collector tanks. They are rare.
They are 3000 psi navy non magnetic tanks and will hold about 82 cu ft.
However I am about 99% certain that spun aluminum (round bottom) tanks cannot be legally requalified and put back in service. There should be a plug in the bottom due to the manufacturing process, and that prevents them from legally being returned to service.
Edit: Luis beat me to it.
However I am about 99% certain that spun aluminum (round bottom) tanks cannot be legally requalified and put back in service. There should be a plug in the bottom due to the manufacturing process, and that prevents them from legally being returned to service.
Edit: Luis beat me to it.
I have one I use for training in my VIP courses. They are indeed USN cylinders never intended for civilian release.
Dale
Dale
699 cu. in. at 3000 holds 80 CF at 3000 psi. I don't know if there were different but similar sizes. They were usually referred to as 90 CF. What is the diameter (or circumference and length? The one that I have is 7 5/8" diameter and 26 1/2" long.
Thanks for the closeup of the stampings. Mine is currently too heavily painted to read anything.
Thanks for the closeup of the stampings. Mine is currently too heavily painted to read anything.
james croft
Contributor
Now you just need to get a non-magnetic DA Aquamaster double hose or a non-mag Conshelf 6 military reg to go with it. Good find, these tanks show up from time to time and some guys collect them. One of the valves looked like a Dacor valve with a plug to screw in an SPG hose.
captain
Contributor
I bought the two tanks from lonestardiver and intend to get them hydroed and doubled back up to go with my Navy half DA Navy half AquaMaster regulator. They look like new inside and were hydroed several times in the past, the latest being 1988. All the hydros were before the current 4 digit dot identifier came into use but it appears they were done commercially as the original hydro only had a dash between the month and year. We shall see.
Attachments
How those that breathe?
I see that you are using a DA can to be able to have the second stage closer to the hose horn, but there is still no venturi flow channeling of any kind. Can you tell much of a difference by relocating the second stage?
Nice looking unit.
I see that you are using a DA can to be able to have the second stage closer to the hose horn, but there is still no venturi flow channeling of any kind. Can you tell much of a difference by relocating the second stage?
Nice looking unit.
captain
Contributor
How those that breathe?
I see that you are using a DA can to be able to have the second stage closer to the hose horn, but there is still no venturi flow channeling of any kind. Can you tell much of a difference by relocating the second stage?
Nice looking unit.
Actually I didn't relocate it. I got the regulator from a retired Navy diver. Being it had a stub hookha port I assumed it was an AquaMaster, it had no lable. When I opened it up I found the DA Navy internals. I showed it to Sam Lecoqe when I was at Portage and he said it was the real deal.
It breathes slightly better than a DA Navy.
Notice that the inhalation side can has a different finish than the exhalation side. Possibly a finish used on a non mag before the black paint is applied.
Some have said that possibly it was a AquaMaster body that someone converted to use the old DA Navy horseshoe but why and it does not have the threaded holes for the AquaMaster horseshoe supports only the ones for the DA Navy horseshoe retainer screws. From what I understand some late production DA Navy's were made with hookah ports and apparently some went to the Navy with the unmachined stub port. In any event it seem to be a very rare version of the DA Navy.
Sam Miller and Ron Miller seem to think it might have been a training regulator or used when the job did not require the non mag.
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From the photos, that difference in color looks like the difference between nickel (brownish- tarnishes) versus chrome (bluish- stays bright). Nickel is slightly magnetic, so if it is nickel it was probably not intended to become a non-mag. Just my guess.
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