Tank Score! Some questions..

[Greenwood_60]

I just followed up a craigslist ad for some steel 72s. They guy had them listed as 3000 psi 72s. I figured he was mistaking them with the fill pressure of an AL80, but I went to check them out anyways. Turns out they are some sort of an early (1977) PST HP100 rated as 3AA 3000+! The problem I have had with 72s in SM is they get a little floaty, and lower volume (most shops balk at jacking them up)... these seem to have all of those issues solved. Reports are people use to complain about how heavy they were, and 3000+ is a respectable 3300psi.

So my question is... do any of you old times know much about these tanks? Buoyancy figures? Actual volume? Tank "trim"?

Thanks!

[DA Aquamaster]

Are they 100s or Faber 72s? Faber 72s are the only 3000 psi 3AA steel tank I am aware of.

My ex-wife liked the Faber 72 a lot and had 4 of them. As I recall they were about 4 lbs negative when empty and about 8.5 pounds negative when full. They worked well for cold water diving as it allowed a significant amount of weight to be removed when diving dry compared to the normal AL 80 she had used in the past.

The bouyancy traits make them too heavy for use as a stage. However as a fairly small 6.75" dia tank they would be potentially interesting as a sidemount tank. The downside for cave diving is that they are a 3AA steel tank with a 3000 psi service pressure. As such a cave fill comparable to the 3600 psi/150% cave fill common with 2400 psi 3AA tanks would be 4500 psi, and that is not likely to happen.

If I can find my Faber log in credentials I could get the actual stats for you. As I recall the actual volume was 71.4 cu ft at 3300 psi.

The internal volume is small and the tank factor is only about 2.2 so at 3600 psi they would only hold about 79 cu ft and at 3800 psi they'd hold about 84 cu ft. In contrast, the longer but similarly small diameter steel 72 has a tank factor of about 2.9 and will hold 86 cu ft at a still reasonably conservative (by cave fill standards) 3000 psi. So oddly enough, I still prefer the older steel 72 to the Faber 72.

Now if you could actually get a 4500 psi fill, they'd hold 97 cu ft in a small package and I'd be much more enthusiastic about them.

---

PST made a mid pressure 72 that was a 3300 psi tank, but 3300 was the service pressure with no plus rating. They were more or less boat anchors being about 12 pounds negative when full. They are very close to the Faber 72 in overall size but are a couple pounds heavier.

[Greenwood_60]

This is the only mention I have found so far. http://www.scubaboard.com/forums/arc.../t-379238.html

I am 100% sure they are "Pst". They look identical to 72s, and measure out to 7.0 diameter, and between 25 an 26" to the bottom of the valve. They are stamped with a + on a few of the hydro stamps.

Let me know if there is any more information I can give you. They are heavy, and galvanized. My primary SM tanks are PST 104s, so I am happy with heavy (no lead and no float)

[cwswine]

Does this help
http://www.huronscuba.com/equipment/...ification.html

[Greenwood_60]

Does this help
http://www.huronscuba.com/equipment/...ification.html

Unfortunately, no. That is always my first stop though. I actually pulled it up while still in the guys driveway!

[FW]

What is the "born date"? If they were from the late 70s they were very heavy.

I tried some back then. One problem was the neck was rather large, and the smaller valves of the time didn't completely cover the O-ring, and it extruded out after awhile. I had one blow in a sump, on a single. I got back to the surface holding my breath. The story is in one of the early UWS issues.

[AB8CD]

What is the "born date"? If they were from the late 70s they were very heavy.

I tried some back then. One problem was the neck was rather large, and the smaller valves of the time didn't completely cover the O-ring, and it extruded out after awhile. I had one blow in a sump, on a single. I got back to the surface holding my breath. The story is in one of the early UWS issues.

You have lived an interesting life, Forrest.

[Greenwood_60]

What is the "born date"? If they were from the late 70s they were very heavy.

I tried some back then. One problem was the neck was rather large, and the smaller valves of the time didn't completely cover the O-ring, and it extruded out after awhile. I had one blow in a sump, on a single. I got back to the surface holding my breath. The story is in one of the early UWS issues.

Yep, '77, and they are very heavy. The L/R valves I just swapped on to them seem to cover the neck well. I will take a closer look to make sure I have metal to metal contact all the way around.

[FW]

Yep, '77, and they are very heavy. The L/R valves I just swapped on to them seem to cover the neck well. I will take a closer look to make sure I have metal to metal contact all the way around.

I think they were sold as HP95s, but I can dig out the article to find out for sure.

[Greenwood_60]

I think they were sold as HP95s, but I can dig out the article to find out for sure.

If that is not too much trouble, that would be great! 95 was the number I came up with calculating based on a 72 filled to 3300.

Thanks!