High pressure tanks with older regs

[WD8CDH]

What are your buds diving and would they get short fills too?

Options at 3000psi:

single HP100=87.2CF
double HP65=113.3CF
double HP80=139.5CF

Then, there is:

double LP45= 90CF at 2640psi
triple LP 45=135CF at 2640psi

Here are some tank spec charts:

Scuba Cylinder Specifications from Tech Diving Limited - 928-855-9400

Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

OMS High Volume High Pressure Steel Scuba Cylinders Specifications http://www.OMSdive.com

XS Scuba Tank Specs

Scuba Tank Specifications

 

[Nemrod]

Or an LP 85 (pressure 2450/2640) at 3,000 is around 96 cf.

N

 

[jbrians]

Or an LP 85 (pressure 2450/2640) at 3,000 is around 96 cf.

N

I am looking seriously at this option. Next choice will be the LP95.
Thanks for the directions!

 

[WD8CDH]

If you look at the specs for a LP85 and an HP100, you will see that they are quite close in dimensions and buoyancy and at the same pressure they hold close to the same amount of air:
Using Worthington cylinders as an example

http://www.xsscuba.com/downloads/steel_cylinder_specs_all.pdf

a LP85 over filled to 3000psi holds 94.2cf and weighs 34.3lb empty and is -0.7lb buoyant
a HP100 underfilled to 3000psi holds 86.7cf and weighs 33.0lb empty and is -2.5lb buoyant

When you add the extra 1.8 pounds of lead to the LP tank to make it the same buoyancy as the HP tank, you are carrying 9.4% more weight for only 8.6% more air with the overfilled LP tank.

If you compare the HP tank at it's service pressure to the LP tank overfilled to 3000psi, you have almost 15% more air but 9.4% LESS weight. It's getting harder and harder to get LP tanks overfilled these days but I find it easier to get 3442psi fills than it used to be.

 

[jbrians]

If you look at the specs for a LP85 and an HP100, you will see that they are quite close in dimensions and buoyancy and at the same pressure they hold close to the same amount of air:
Using Worthington cylinders as an example

http://www.xsscuba.com/downloads/steel_cylinder_specs_all.pdf

a LP85 over filled to 3000psi holds 94.2cf and weighs 34.3lb empty and is -0.7lb buoyant
a HP100 underfilled to 3000psi holds 86.7cf and weighs 33.0lb empty and is -2.5lb buoyant

When you add the extra 1.8 pounds of lead to the LP tank to make it the same buoyancy as the HP tank, you are carrying 9.4% more weight for only 8.6% more air with the overfilled LP tank.

If you compare the HP tank at it's service pressure to the LP tank overfilled to 3000psi, you have almost 15% more air but 9.4% LESS weight. It's getting harder and harder to get LP tanks overfilled these days but I find it easier to get 3442psi fills than it used to be.

So why did I think the HP100 was an 8" tank? Probably ignorance.....

 

[jbrians]

Called the LDS and ordered 2 HP100's

This hopefully, will give me the best of both worlds....more air and less weight on my belt to sink a 7mm but not so much that I can't dive with a thin suit and still maintain a margin of safety.

 

[captain]

The PST tank you were asking about on VDH, special permit 9791 is good until 5/31/2011 unless the permit is renewed by PST.

http://www.phmsa.dot.gov/staticfiles/PHMSA/SPA_App/OfferDocuments/SP9791_2007060054.pdf

 

[Nemrod]

The LP85 I am referring to is the Faber 7.0 inch diameter tank.

N

 

[jbrians]

The LP85 I am referring to is the Faber 7.0 inch diameter tank.

N

I liked the idea of the 7" Faber tank, however the LDS that I like around here don't carry that brand, quoting too much shipping money involved to get from Distribution centre to retail outlet.
I expect the Worthington X7-100 will work for me pretty much as well.

 

[Slonda828]

While we are on the subject of heavy yokes, why is the conshelf XII rated at 4000 PSI while the XIV and subsequent are rated at 3000-3500 PSI? Anyone know why this is?