Question Older steel tank size

[JackTheCracker]

Hello everyone,

Got three steel tanks for free, hydro passed , vis was great and have been diving them, both are narrow neck Hp deep din. I think they are 120s but not sure. They measure 71.5ish cm tall and about 17.5 cm dia. Heavy has hell but I get tons of bottom time with them.

Can anyone identify was size they might be?

 

[inquis]

If they are indeed 15.3L volume at 3500 psi, that works out to 122 cuft including non-ideal gas compression effects.

 

[ScubaBunga]

Hello everyone,

Got three steel tanks for free, hydro passed , vis was great and have been diving them, both are narrow neck Hp deep din. I think they are 120s but not sure. They measure 71.5ish cm tall and about 17.5 cm dia. Heavy has hell but I get tons of bottom time with them.

Can anyone identify was size they might be?

great deal no matter what size they are.

 

[stretchthepenn]

They look like 120s. I had a very similar pair with different stamps (IIRC) but the same characteristics.

 

[rx7diver]

Hello everyone,

Got three steel tanks for free, hydro passed , vis was great and have been diving them, both are narrow neck Hp deep din. I think they are 120s but not sure. They measure 71.5ish cm tall and about 17.5 cm dia. Heavy has hell but I get tons of bottom time with them.

Can anyone identify was size they might be?

Your cylinders have same markings, and same height, as my PST HP120's (which were sold as Sherwood Genesis HP 3,500 psig cylinders). But my cylinders have outer diameter 7.25" (= 18.4 cm), same as an Alum 80.

ETA: See SCUBA Cylinder Specifications – Huron Scuba, Snorkel & Adventure Travel Inc. PADI 5 star IDC in Ann Arbor, MI.

rx7diver

 

[JackTheCracker]

Wow I appreciate the response, thank you for the confirmation. I sort of eye balled size, but good to know, I thought they might be 100s but the amount of bottom time I get I was suspicious that couldn’t be the case.

 

[rx7diver]

Wow I appreciate the response, thank you for the confirmation. I sort of eye balled size, but good to know, I thought they might be 100s but the amount of bottom time I get I was suspicious that couldn’t be the case.

The 3,500 psig HP120 is ~28" tall. The 3,500 psig HP100 is ~24" tall. And the 3,500 psig HP80 is ~20" tall. All three have OD = 7.25" (same as an Alum 80).

The HP120 is a bit too tall for me to dive comfortably as a BM single; the HP100 is perfect for me for this. (I am 6'2" with longer legs and shorter torso.)

But HP120 BM doubles were perfect for me when diving dry; HP100 BM doubles were a bit too short for me to dive comfortably--although HP100 BM doubles were exactly what I dove when I first began extended range diving in the Great Lakes (tons of gas for me for this, favorable buoyancy characteristics for drysuit diving, not terribly heavy out of the water). I switched to HP120's later, when I needed more gas for deeper/longer exposures.

rx7diver