Vintage Double Hose

Does anyone have information on the triple sets that US Divers made that come in the plastic backpack? Ive only seen a few pictures of them and they are always in yellow. I may pick up a set with black tanks, solid bar manifold and a blue case. Are these 30s or 40s and what type of alloy? Im trying to get better pictures from the seller.

Ah ha, its the ABS system. Found a post on scubaboard with lots of pictures.

I've been looking for that manifold for awhile if you pass on it can you get me in touch with the seller

If it has the solid manifold on the top is the ABS system. If you are referring about the one with the manifold on the bottom and the built in regulator, it is the UDS-1 System.

Either one came with the AL6351 aluminum alloy.

Bummer. I guess I'll pass.

I believe that the ABS system was only around in the 80's (and therefore only made out of AL6351). But I don't know for sure that there were none made in the 90's. If they were any made in the 90's (or maybe even 1989) then they would have been made out of AL6061-T6.

Before you totally pass, I would just ask the seller for a picture of the neck showing the original date. That would be the definitive proof. There is a publish list from Luxfer that tells when each size tank was transitioned from AL6351 to AL6061.

The same size cylinders (30's and 40's cu ft) are still made now-a-days (out of AL6061). If you can get a hold of a manifold, you can set it up with newer tanks.

The original hydro was 9/87. Last hydroed in 04.

If they are made in 87 I am pretty sure it is the bad 6351 alloy.

Considering the possibility of cracking, a surprising number of people still use the 6351 cylinders. Personally, I don't want to take the risk, however small it might be. I sold thirteen of them for scrap even though a friend in Belize wanted to pay more for them, and have them shipped there. I know that they would have been abused and neglected there, and just wouldn't do it.

Most shops here won't fill them, but I still know a at least three that seem to think they are ok, and still use them in their class/rental stock.

For the latest info on testing them I just spoke with the manager of Cylinder Services, probably the largest hydro facility in north Texas. I had heard that they no longer tested pre-1990 aluminum cylinder, but he clarified that rumor, stating certain DOT exemption numbered cylinders were still ok to test. He sent me an email saying that they will only test ones with the following exemption numbers:

"Hello Bill, here are the exemptions that are allowed by the DOT...
6498, 7042, 8107, 8364, and 8422. If you have any question please fill free to call."

He also stated that they perform Eddy Current Testing on all pre-90 aluminum cylinders.

None of the shops around here would fill them. Just as well. I dont need more tanks, but triples are neat.

Was there anything special about the tanks or could modern al30s be put in their place?

I am pretty sure that all the ABS units used the same size and valve threads (3/4” NPS) as the modern 30 or 40 cu ft cylinders (made out of AL6061-T6).

The manifold can be used with either 30’s or 40’s, but I don’t remember which ones fit in the case. I think it was the 40’s. They are the same diameter, only the length is different.

The UDS-1 used a different cylinders. They used unique 1” NPS threads. I don’t believe that type of cylinder has ever being available from other applications.

What would something like this go for if you had to replace the tanks?

I have one of the USD triples manifolds, it's very cool. Problem I have is the spacing is too tight to fit AL40's, which would be my choice of tanks for cost vs capacity reasons. They have a standard 3/4" thread on them, I am looking (very casually) for three larger capacity small diameter rebreather cylinders (steel) to put together. The issue with using this with a double hose reg is the connection is on the side, not in the center.

I think Luxfer 30s will fit into that manifold


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