Well, this is interesting... Triple tank vintage rig

[Johnoly]

Well that sure makes calculating " 1/3rds " easy !! LOL!

 

[Angelo Farina]

Well that sure makes calculating " 1/3rds " easy !! LOL!

Actually not that easy. If you look carefully, the tank has a valve system with a reserve lever.
The reserve intercepts gas inside one of the three bottles only.
So it starts acting around 150 bars, below that pressure you get air from just the two other bottles. When they are empty you pull the reserve rod, and the 150 bars stored in the closed bottle distribute evenly in all the three bottles, making the typical "tweeeng" sound.
At that point you get 50 bars over the whole volume of 3 bottles.
If you want to use this triple tank for diving on the "thirds rule" you must account that initially (say at 180 bars) the pressure shown by the SPG has to be multiplied for the volume of all the 3 tanks (say 15 liters).
At 150 bars the rightmost tank closes due to the reserve valve, so after this point the SPG pressure must be multiplied by just the volume of 2 bottles (say 10 liters).
This makes it very hard to define the turn-over pressure, when the tank contains 2/3 of the initial content.
Definitely using such a tank with the thirds rule is not trivial.
The solution could be to lock the reserve valve on the open position. But this would remove the additional safety provided by the reserve mechanism, which is one of the nice things of such a vintage setup.

 

[Scared Silly]

So did those prices for the tanks include the double hose regulator?
Very hard to read.

Yes, "Each "Aqua-Lung" is composed of a regulator, a cylinder, a value, and a harness."

That said I do not think the cylinders shown in the advert by the OP are PST scuba cylinders as there are threads on the outside of the cylinder. I suspect like many of that ere the cylinders have been repurposed. I would go as far to say that the inside threads were tapped so to accommodate the valve.

 

[JohnN]

I'm going to take a flyer on those tanks. I'll be in the Oak Harbor area this Sunday, I"ve spoken with the seller and we've agreed to meet up.

It should be interesting. I've contacted the hydro shop I use and they said they had no problem doing a test on the tanks.

I'll post details when I have them

 

[Gone for diving]

I'm going to take a flyer on those tanks. I'll be in the Oak Harbor area this Sunday, I"ve spoken with the seller and we've agreed to meet up.

It should be interesting. I've contacted the hydro shop I use and they said they had no problem doing a test on the tanks.

I'll post details when I have them

Not sure I would let anyone hydro them.
You better be real sure, that who ever touches them knows what they are doing. (Brass threads and all)

I would just vis them, and fill them,
And stay at rated pressure no over pumping,

Glad someone is getting them, for the price it's a no brainer.

 

[Eric Sedletzky]

Yes, "Each "Aqua-Lung" is composed of a regulator, a cylinder, a value, and a harness."

That said I do not think the cylinders shown in the advert by the OP are PST scuba cylinders as there are threads on the outside of the cylinder. I suspect like many of that ere the cylinders have been repurposed. I would go as far to say that the inside threads were tapped so to accommodate the valve.

Wow, a DA Aquamaster, a set of triples, and a harness for $250, all brand new.
But then journeyman wage was what 3 or 4 bucks an hour back then?

 

[Cthippo]

I'm going to take a flyer on those tanks. I'll be in the Oak Harbor area this Sunday, I"ve spoken with the seller and we've agreed to meet up.

It should be interesting. I've contacted the hydro shop I use and they said they had no problem doing a test on the tanks.

I'll post details when I have them

Excited to hear how they turn out!