Specs on the old 72cf steel tanks?

[engdiver]

Does anyone know the specs on the old 72cf 2250 psi steel tanks? Looking for the dia, length, weight empty and buoyancy empty.

 

[rjack321]

6.9 to 7.0 inch diameter
~25 inch long
empty weight ~30 lbs
empty bouyancy neutral to +1

All dimensions varied slightly by manufacturer, both PST and Norris made steel 72s - not sure about Worthington.

 

[SparticleBrane]

They kinda look like this!

 

[Luis H]

This data came from one of my US divers 1970's maintenance and repair manuals:

72 cu ft Standard

Service pressure, psi : 2250
Actual air capacity, ft3 (at 2475 psi): 71.55
Outer diameter, in: 6.81
Length without valve, in: 25.12
Empty weight, lbs (w/o valve): 26
Buoyancy Empty, lbs (w/valve): 0
Buoyancy Full, lbs (w/valve): -5.4

They are not all the same. As mentioned above, there were at least two manufacturers of this cylinders, and they were built for many years. They came with 1/2" tapered pipe thread, 3/4" straight pipe thread, and some even had 1/2" straight pipe threads (mostly Sportsways).
Out of all my 72's one in particular is taller than the rest. There are also other smaller variations.

 

[engdiver]

Thanks all for the info. I am considering using these as a double set-up.

I noticed PST makes an MP-72 tank also with -6 lb Buoyancy empty. Has anyone used these as doubles to lower the amount of required lead?

 

[dsteding]

One related question: is it still possible to find manifolds for the non-standard sized threaded tanks? I have a line on two mid-70s 72s for $50 each, they need hydro and viz, but I figure they might be a decent set of small doubles on the cheap.

 

[rjack321]

Mid 1970s steel 72s should have standard (for today) 3/4" theads.

 

[rjack321]

Thanks all for the info. I am considering using these as a double set-up.

I noticed PST makes an MP-72 tank also with -6 lb Buoyancy empty. Has anyone used these as doubles to lower the amount of required lead?

You will be seriously overweighted in those - and its all up by you head! Faber makes lots of very heavy "MP" and "HP" tanks and all are a pita. Not recommended, YMMV

 

[pescador775]

Thanks all for the info. I am considering using these as a double set-up.

I noticed PST makes an MP-72 tank also with -6 lb Buoyancy empty. Has anyone used these as doubles to lower the amount of required lead?

I am not familiar with this tank. However, Scubapro sells an MP 72 rated 3000 plus which is manufactured by Faber. This compact tank has had some popularity with women.

In 1970's-80's, PST manufactured a MP 94.6 rated 3000 plus. It is the same size as a "72" except that it is 1/10 inch larger diameter. As with all 3000 psi chrome moly tanks made to 3AA specs, it is very negative and not popular in doubles configeration. However, it seems to me that a dry suit diver might make use of such a setup. In Europe, the rather heavy, 4400 psi tanks are used by dry suit divers.

Twin 72's are old school but retain some popularity. Many manifolds and bands/packs are available for these. They are mainly good for two short dives or a single dive requiring 10-15 minutes decompression.

 

[cool_hardware52]

Thanks all for the info. I am considering using these as a double set-up.

I noticed PST makes an MP-72 tank also with -6 lb Buoyancy empty. Has anyone used these as doubles to lower the amount of required lead?

The 3300 psi ScubaPro / Faber 72's are nuggets, heavy. They are small tanks. My fundies instructor used them exclusively during my class.

I personally prefer a longer tank.

Tobin