US Divers Tanks Question?

[kworkman]

I'm looking at getting a set of Aqua Lung/US Divers twin tanks that are black and have the aqua lung label in gray. They are steel and marked 3AA2015. The owner said they are smaller than his aluminum tanks. The earliest hydro I can find is 9/73. I was thinking double 53s but the 73 catalog doesnt have them and the 72 catalog only has them in yellow. Any thoughts? Thank you.

[antique diver]

Those sound like the "42's" that were originally sold by the Survivair division for SCBA use in Fire Departments and industrial applications. Since they had the same neck threads as SCUBA some of these appear to have also found their way into the Aqualung division. They are about the same size as the old 1800 psi 38's, but have more of SCUBA tank bottom... not the rounded/hemispherical shape of the early 38's. The ones labeled Survivair came painted white, but I am not sure what color was originally used on the diving version. Come to think of it, I think I remember some white cylinders showing up in the commercial diving division catalog.

I have a couple of these that make great diving cylinders. A little heavier in the water than 38's (just about right in my opinion), but basically the same size. And they have the easier to service straight threads with oring seal like modern SCUBA.

You will probably like them.

[kworkman]

I have a set of voit 50s that you helped me with and a set of 38s. Ive never used the 50s yet. Are they similar buoyancy characteristics?

[antique diver]

The 2250 psi 50's seem heavier, but I have only used the 42's (or whatever they really are)in singles, and my 50's are doubles, so I couldn't give you a very accurate comparison of the buoyancy characteristics.

I just looked at both of my single 42's, and they also were made in 1973, and both are marked "USD". I know that these were originally white Survivair SCBA cylinders due to where I obtained them.

[kworkman]

Sounds good to me.