LP72 Doubles w/Selpac Manifold: what bands?

[Ghetto Diver]

I thought I had this figured out, but no.
I am doubling a set of lp72's with a Selpac double yoke. I the old bands I have are actually narrower than I figured <8".
The Selpac is 8.125" [correct me if I'm wrong]
What options do I have?

 

[John C. Ratliff]

There are twin 72 tank bands/backpacks available, but they are 6 3/4 inches, I believe, in diameter. I see at least one on E-Bay right now.

SCUBAPAK Double Twin Dive Tank Holder with Backpack For Scuba Diving | eBay

SeaRat

 

[JamesBon92007]

The double band for my little 45s (50s?) is stainless steel and, like SeaRat said, is about 6 1/2- 6 3/4 inches, with room for some adjustment. There are no manufacturers markings but the backpack is USD. So that is two Voit tanks with a USD manifold and backpack.

The double bands for my 72s are galvanized steel and the same diameter as the other. They may or may not be ScubaPro--they are currently disassembled and mixed with some other stuff, including a ScubaPro backpack plus a generic one. The bands are not marked that I can see.

 

[Ghetto Diver]

There are twin 72 tank bands/backpacks available, but they are 6 3/4 inches, I believe, in diameter. I see at least one on E-Bay right now.

SCUBAPAK Double Twin Dive Tank Holder with Backpack For Scuba Diving | eBay

SeaRat

The one I have is a stainless version of this.
I have sourced new repro's through VDH. Haven't purchased yet as I am selling other stuff.
Hopefully will get resolved this weekend.

I am planning on using a DH reg that I acquired on the center post, yet leaving me options to use my single hose sets as well [no tech diving].

Thanks for your help.

 

[JamesBon92007]

I think my small doubles are known as "44s." From what little I've been able to find out they are probably 40 cu/ft at 2250 psi and about 44 each at 2475 psi. There were some that were known as Orange County Twin 44s but they apparently used a backplate. Does anyone happen to have a picture of OC Twin 44s? I guessed that they are about 90 cu/ft but was never certain. And yes, they were purchased in Orange County

Judging from the age of the tanks and the wide, thick, black nylon straps on the backpack I'm thinking the backpack was probably not original.

In case is was not clear they are the same diameter as the steel 72s.

 

[Ghetto Diver]

My OP wasn't clear....the center to center is too narrow for the bands that I have.
No idea what manifold they fit, but definitely not the Selpac. I dive ID's as well, so they fit fine without the manifold.

 

[JamesBon92007]

On both of my sets of bands the center to center distances is approximately 8 1/4" and that's within about 1/16" and there is no adjustment as far as I can see. That is awfully close to your "8.125" which makes me wonder if you have bands that are meant for different tanks such as "40s" which are smaller in diameter than 72s. At less than 8" I'm imagining there's barely enough room for a bolt to mount the bands to the backplate or backpack.

 

[Ghetto Diver]

Bought a set of these...
A&D Adventures Other Vintage Scuba Stuff
Works fine.

 

[george_austin]

I think my small doubles are known as "44s." From what little I've been able to find out they are probably 40 cu/ft at 2250 psi and about 44 each at 2475 psi. There were some that were known as Orange County Twin 44s but they apparently used a backplate. Does anyone happen to have a picture of OC Twin 44s? I guessed that they are about 90 cu/ft but was never certain. And yes, they were purchased in Orange County

Judging from the age of the tanks and the wide, thick, black nylon straps on the backpack I'm thinking the backpack was probably not original.

In case is was not clear they are the same diameter as the steel 72s.

1.) Can you get me a measurement on the overall length of one of those "44's" ? - from the bottom of the tank to the neck horizontal plane (face)
2.) Is 2250 stamped on tank shoulder?
3.) Any indication of tank manufacturer?

I have a set of Walter Kidde steel tanks (haven't picked them up yet) that are 20.5 inch from bottom to top (without valve) 1800 psi stamped on shoulder, ICC 3AA
CM4 (Chrome moly steel) - I think they may be a long lost set of original "Orange County 44's They have the .75 NPST valve hole - nice - now lets have a look inside and see if there's any corrosion in there before hydro and sticker. Total weight right now is 58 lbs so I think, based on that weight, that they may be full of air since about 1965 LOL.

 

[JamesBon92007]

1.) Can you get me a measurement on the overall length of one of those "44's" ? - from the bottom of the tank to the neck horizontal plane (face)
2.) Is 2250 stamped on tank shoulder?
3.) Any indication of tank manufacturer?

I have a set of Walter Kidde steel tanks (haven't picked them up yet) that are 20.5 inch from bottom to top (without valve) 1800 psi stamped on shoulder, ICC 3AA
CM4 (Chrome moly steel) - I think they may be a long lost set of original "Orange County 44's They have the .75 NPST valve hole - nice - now lets have a look inside and see if there's any corrosion in there before hydro and sticker. Total weight right now is 58 lbs so I think, based on that weight, that they may be full of air since about 1965 LOL.

My twins measure approximately 18.5" from the bottom to where the neck begins and about 20" to the top of the neck (not including the valve). Compare this to a 72 that measures about 25" to the bottom of the neck. This works out to the small tanks being approximately .74 the size of a 72 which would be about 53 cu/ft. They are stamped ICC 3AA 2250 and "VOIT" opposite the 3AA stamp. The original hydro date is 2-67. The tanks are 6.9" diameter just like the typical 72s. They are connected together with a US Divers J-Valve double manifold, stainless steel bands, and have plastic boots so they stand up nicely.

Unlike yours mine have several hydro stamps so the air is fresher than 1965 They are also clean and shiny inside and were hydroed in 2011 and will be getting their next hydro in a week or two.

As soon as I get them back from hydro I'm going to fill one with water and measure the volume and weight of the water so I can determine the capacity of the tanks. So far I'm thinking that they are probably right around 50 cu/ft at 2475 psi so that should be around 108 cu/ft (together) at 2700 psi

Since my girlfriend started diving I have not gone diving alone so I may end up selling them, however it would be easy to replace the little tanks with 72s or separate them for shore dives in shallow water in places where I might not want to take a heavier tank. It's usually a bad idea to get rid of equipment.

I have an old CO2 tank rated at 1800 but it takes a 1/2" tapered valve so I have not put air in it but it might be fun to have a little tank to play with. I check eBay periodically but so far nobody seems to want me to have their old valve at a cheap price.

Edit: I just noticed where you are and you said you haven't picked up the tanks yet. Would those by any chance be the ones the guy in San Diego is selling on Craig's List? He had several sets and called them "38s." At $50/set I was very tempted...