Updated SCUBA tank specifications list -- in PDF and spreadsheet
- Thread starter tmassey
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Mike1967
Contributor
Scared Silly
Contributor
One thing to note that many many fail to do is read the fine print. Faber does their buoyancy measurements sans valve. Worthington does not.
Faber: Buoyancy in salt water, tank only!
Blue Steel Scuba - Cylinder Specs
Worthington: In sea water with valve.
http://www.drexler.ca/diving/images/products/worthington_steel_specs.pdf
As such, so while the specs may be directly from the mfg. direct comparisons can be misleading. For instance, look at the LP85 at the end of the day the only real difference is about 3lbs dry weight. Everything else is, for all intents and purposes, the same.
For the OP for completeness include the odds and ends cylinders. Sometimes having them is useful. As they do get referenced now and then.
Faber: Buoyancy in salt water, tank only!
Blue Steel Scuba - Cylinder Specs
Worthington: In sea water with valve.
http://www.drexler.ca/diving/images/products/worthington_steel_specs.pdf
As such, so while the specs may be directly from the mfg. direct comparisons can be misleading. For instance, look at the LP85 at the end of the day the only real difference is about 3lbs dry weight. Everything else is, for all intents and purposes, the same.
For the OP for completeness include the odds and ends cylinders. Sometimes having them is useful. As they do get referenced now and then.
2airishuman
Contributor
Thank you, good work.
I have performed actual controlled measurements of cylinder buoyancy and have found that manufacturer's specifications in this area are often incorrect. There's a lot of wiggle room in the net buoyancy of the valve, which varies, what constitutes an "empty" cylinder (500 psi? atmospheric pressure? in between?), manufacturing tolerances, and the density of the water used for the test.
I have attached PST specification PSTC-260 which contains some of the information you want. In particular the water capacity is given as 26 lbs 5 oz. or 730 cubic inches. I have a good sized collection of PST and Norris LP72s. The empty weight is usually given as 27.8 for these and I believe that's about right with no valve. When I weighed all mine the weights were all within one pound including both the PST and Norris cylinders. This is less variation than I have seen between Worthington HP120s manufactured a year or two part that are identical except for serial number. For LP72s, my notes show a weight of 29.87 pounds with a Thermo provalve and a measured buoyancy while empty (0 PSI) of +0.51 pounds in freshwater again with a Thermo valve for a representative PST cylinder from my collection. The buoyancy figure was measured using a container of tap water, a digital scale accurate to 1/4 ounce, and a partially filled cylinder. Results were adjusted for the mass of the gas in the cylinder. I did not measure the density of the tap water however there is some mineral content locally so the density would be somewhat greater than 1 kg/l.
I have performed actual controlled measurements of cylinder buoyancy and have found that manufacturer's specifications in this area are often incorrect. There's a lot of wiggle room in the net buoyancy of the valve, which varies, what constitutes an "empty" cylinder (500 psi? atmospheric pressure? in between?), manufacturing tolerances, and the density of the water used for the test.
I have attached PST specification PSTC-260 which contains some of the information you want. In particular the water capacity is given as 26 lbs 5 oz. or 730 cubic inches. I have a good sized collection of PST and Norris LP72s. The empty weight is usually given as 27.8 for these and I believe that's about right with no valve. When I weighed all mine the weights were all within one pound including both the PST and Norris cylinders. This is less variation than I have seen between Worthington HP120s manufactured a year or two part that are identical except for serial number. For LP72s, my notes show a weight of 29.87 pounds with a Thermo provalve and a measured buoyancy while empty (0 PSI) of +0.51 pounds in freshwater again with a Thermo valve for a representative PST cylinder from my collection. The buoyancy figure was measured using a container of tap water, a digital scale accurate to 1/4 ounce, and a partially filled cylinder. Results were adjusted for the mass of the gas in the cylinder. I did not measure the density of the tap water however there is some mineral content locally so the density would be somewhat greater than 1 kg/l.
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Charles2
Contributor
I wasn't able to figure it out. Can you give us a little more information? Or perhaps make your point so that we will have a clearer understanding?
I really wasn't aware that Australia had different tanks than other parts of the world, although it does not surprise me. I had heard that inspections and tests were required more frequently.
In your mind, what is it about Australian tanks that make them superior to USA tanks? Or European tanks, for that matter?
Mike1967
Contributor
Charles2
Contributor
Interesting observation however slight.
On the face of it, the biggest advantage in your tanks appears to be that they are considerably lighter. For instance, and if I read the tables correctly, an Australian standard HP100 weighs 28.4 pounds while in the USA, an HP100 weighs 34.0 pounds. I think most of us would much rather schlep the lighter tanks. The buoyancy difference seems almost negligible by comparison.
Thanks for the info.
Mike1967
Contributor
Nice work, @tmassey. But, I'm a little disappointed that none of the older 3500 psi tanks are in the list. I have several PST E7 series 100 and 120 3500 psi tanks. They were in the Huron cylinder specs list.
I think it would be better to have a tank in the list, even if the spec source is the Huron list, than to not have the tank in the list at all.
I think it would be better to have a tank in the list, even if the spec source is the Huron list, than to not have the tank in the list at all.
OP
tmassey
Contributor
Hey, the Huron list is still there. Use it. I own about a half-dozen of them too. But two things: the differences are small. And the purpose of this list is to be authoritative. Otherwise, what’s the point?
I’ve said from the first post: this is not supposed to be a comprehensive list. It’s supposed to be a traceably accurate list. That is non-negotiable. To me, that and the water volume are the only actual value of this list.
So as soon as anyone finds a manufacturer created spec list for those tanks, I’ll add them.
(Don’t like my rules? Make your own — I even gave you the spreadsheet!)
The one that irritates me more are the OMS tanks — and I don’t even own any of them. But they’re very popular in certain areas: it seems that 3/4 of Amigos rental fleet are OMS...
. But with no manufacturer-supplied info... use the Huron list. You still have the Internet, right?
I’ve said from the first post: this is not supposed to be a comprehensive list. It’s supposed to be a traceably accurate list. That is non-negotiable. To me, that and the water volume are the only actual value of this list.
So as soon as anyone finds a manufacturer created spec list for those tanks, I’ll add them.
(Don’t like my rules? Make your own — I even gave you the spreadsheet!)
The one that irritates me more are the OMS tanks — and I don’t even own any of them. But they’re very popular in certain areas: it seems that 3/4 of Amigos rental fleet are OMS...
. But with no manufacturer-supplied info... use the Huron list. You still have the Internet, right? Similar threads
