steel vs alu tanks

dreamdive · 10th August 2007, 23:47

I finally received the Optima and started training on it using 14cf alu tanks.

Should I get steel tanks for future dives and if so what kind and from whom? I had originally ordered steel tanks but they are no longer available.

Since I am one of the newborns of this group, any feedback is totally appreciated. Thanks!!

edasque · 11th August 2007, 01:51

from what I understand my LP27 were the last one made for Dive Rite for the O2ptima. I don't know if steel stanks will still be available for it.

I think they had been made especially for the O2ptima.

zmcave · 11th August 2007, 12:19

I like having the large steel tanks. It gives me more autonomy, I can dive all weekend without having to fill my tanks. As for the extra weight... I need it anyway!
Now, if they are not making the LP27 any more it's a matter to find a large steel tank that fits the rig. I am pretty sure the dumpy 3L found in europe would fit, but I don't think you will find them in the US. DR express has these worthington Steel tanks, HP30, that might fit. I am sure Mark can let us know.
Good luck,

Zé.

JCdesign97 · 11th August 2007, 14:13

My Optima came with the LP27s and they just make the unit way too butt-heavy for me. I have since bought a set of the Catalina AL20s and also the AL13s. I have pretty much no use for the 27s anymore as far as I can see, so as they're no longer available I guess now might be a good time to offer them up for sale to anyone who might be interested ...

***caveseeker7*** · 11th August 2007, 22:05

What are the max tank size that would fit?

The original steel tanks used on the Optima looked a lot like the tanks
that are used on SCRs like the Dräger (4 ltr/27 cf I believe) or the Azimuth.

Also, 2 ltr steel tanks (13 cf in the US) might work.
With so many units owned by Rebreather World members we should be able to find
tanks within the max measurements.

n2diving · 12th August 2007, 10:52

The O2ptima FX model will accept a variety of cylinder sizes using standard left and right modular DIN valves. Including the valve, the maximum cylinder dimensions are 18.5-inches in length by 5.5-inches in diameter. The AL 13's, AL 14's, AL 20's will all work in the aluminum sizes (Note the AL 19 size will not work). In steel the original low pressure PST 27's are no longer available and frankly they are so negative that a drysuit is required to trim out correctly. Worthington is no longer making the steel high pressure 13's and 30's, but there are still some around if you hunt and Worthington may well make another run of the 30's. Faber makes an equivalent US size steel 15 (2L). The steels all cause your trim to be very 'butt heavy'.

As a practical matter, the AL13's with two 2 lb trim weights (total for 4 lbs) is the best solution for most divers. The AL20's are the best solution for divers who want more gas. These trim out nicely regardless of diving wet or dry. I've got several sets of used LP27's and used HP13's gathering dust if anyone is interested, but the price would be no bargain. -- Mark

JCdesign97 · 12th August 2007, 18:32

Quote: (Originally Posted by n2diving)

...

As a practical matter, the AL13's with two 2 lb trim weights (total for 4 lbs) is the best solution for most divers. The AL20's are the best solution for divers who want more gas. These trim out nicely regardless of diving wet or dry. I've got several sets of used LP27's and used HP13's gathering dust if anyone is interested, but the price would be no bargain. -- Mark

Hi Mark - inadvertently tying this thread to your other posts about the revised EAC duration relative to CO2 absorbed/O2 consumed (apologies for going partially off-topic), do you have the specs on the capacity in liters/internal volume of the AL20s? I have the info for the 13s and I believe you explained that, as well; but I can't find the same on the 20s. Trying to establish what psi used equates to 240 liters of O2 in the 20s ...

Many thanks in advance,

n2diving · 12th August 2007, 20:32

The AL20's are rated at 20 cu ft @ 3000 psi... I don' t have the water volume, sorry.

zmcave · 12th August 2007, 20:38

Quote: (Originally Posted by JCdesign97)

Hi Mark - inadvertently tying this thread to your other posts about the revised EAC duration relative to CO2 absorbed/O2 consumed (apologies for going partially off-topic), do you have the specs on the capacity in liters/internal volume of the AL20s? I have the info for the 13s and I believe you explained that, as well; but I can't find the same on the 20s. Trying to establish what psi used equates to 240 liters of O2 in the 20s ...

Many thanks in advance,

The 20cf rated at 3000 has 2.7 liters of volume.
So, if filled at 3000 psi, 207 bar, it will have a total of 540 liters.
Down here we don't boost O2, so we usually get about 2400 psi, 160 bar, and thats a total of 432 liters.
To try answer your question, the 240 liters of O2 in a 20cf tank is about 88 bar of use, or something like 1300 psi.

hope it helped.

Zé.

JCdesign97 · 12th August 2007, 21:58

Quote: (Originally Posted by zmcave)

The 20cf rated at 3000 has 2.7 liters of volume.
So, if filled at 3000 psi, 207 bar, it will have a total of 540 liters.
Down here we don't boost O2, so we usually get about 2400 psi, 160 bar, and thats a total of 432 liters.
To try answer your question, the 240 liters of O2 in a 20cf tank is about 88 bar of use, or something like 1300 psi.

hope it helped.

Zé.

Obrigado Ze, perfect - much appreciated!

10th August 2007, 23:47	#1 (permalink)
dreamdive New Member Current Rebreather/s: Optima Other Rebreather/s: Join Date: May 2007 Location: Florida Posts: 6	steel vs alu tanks I finally received the Optima and started training on it using 14cf alu tanks. Should I get steel tanks for future dives and if so what kind and from whom? I had originally ordered steel tanks but they are no longer available. Since I am one of the newborns of this group, any feedback is totally appreciated. Thanks!!
(Offline)

11th August 2007, 01:51	#2 (permalink)
edasque French Erik Current Rebreather/s: Optima Other Rebreather/s: Join Date: Apr 2007 Location: Boston, MA Posts: 264	Re: steel vs alu tanks from what I understand my LP27 were the last one made for Dive Rite for the O2ptima. I don't know if steel stanks will still be available for it. I think they had been made especially for the O2ptima.
(Online)

11th August 2007, 12:19	#3 (permalink)
zmcave www.rebreather.com.br Current Rebreather/s: Optima Dolphin Other Rebreather/s: Optima Dolphin Join Date: Apr 2006 Location: Brazil Posts: 186	Re: steel vs alu tanks I like having the large steel tanks. It gives me more autonomy, I can dive all weekend without having to fill my tanks. As for the extra weight... I need it anyway! Now, if they are not making the LP27 any more it's a matter to find a large steel tank that fits the rig. I am pretty sure the dumpy 3L found in europe would fit, but I don't think you will find them in the US. DR express has these worthington Steel tanks, HP30, that might fit. I am sure Mark can let us know. Good luck, Zé.
(Offline)

11th August 2007, 14:13	#4 (permalink)
JCdesign97 My unit can beat up yours Current Rebreather/s: Optima Other Rebreather/s: Join Date: Mar 2007 Location: PA, USA Posts: 382	Re: steel vs alu tanks My Optima came with the LP27s and they just make the unit way too butt-heavy for me. I have since bought a set of the Catalina AL20s and also the AL13s. I have pretty much no use for the 27s anymore as far as I can see, so as they're no longer available I guess now might be a good time to offer them up for sale to anyone who might be interested ... __________________ Cheers, John Cogan
(Online)

11th August 2007, 22:05	#5 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,495	Re: steel vs alu tanks What are the max tank size that would fit? The original steel tanks used on the Optima looked a lot like the tanks that are used on SCRs like the Dräger (4 ltr/27 cf I believe) or the Azimuth. Also, 2 ltr steel tanks (13 cf in the US) might work. With so many units owned by Rebreather World members we should be able to find tanks within the max measurements. __________________ Cheers Stefan "Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"
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12th August 2007, 10:52	#6 (permalink)
n2diving Custom Title Allowed! Current Rebreather/s: Optima Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Feb 2005 Location: Florida, USA Posts: 271	Re: steel vs alu tanks The O2ptima FX model will accept a variety of cylinder sizes using standard left and right modular DIN valves. Including the valve, the maximum cylinder dimensions are 18.5-inches in length by 5.5-inches in diameter. The AL 13's, AL 14's, AL 20's will all work in the aluminum sizes (Note the AL 19 size will not work). In steel the original low pressure PST 27's are no longer available and frankly they are so negative that a drysuit is required to trim out correctly. Worthington is no longer making the steel high pressure 13's and 30's, but there are still some around if you hunt and Worthington may well make another run of the 30's. Faber makes an equivalent US size steel 15 (2L). The steels all cause your trim to be very 'butt heavy'. As a practical matter, the AL13's with two 2 lb trim weights (total for 4 lbs) is the best solution for most divers. The AL20's are the best solution for divers who want more gas. These trim out nicely regardless of diving wet or dry. I've got several sets of used LP27's and used HP13's gathering dust if anyone is interested, but the price would be no bargain. -- Mark
(Offline)

12th August 2007, 18:32	#7 (permalink)
JCdesign97 My unit can beat up yours Current Rebreather/s: Optima Other Rebreather/s: Join Date: Mar 2007 Location: PA, USA Posts: 382	Re: steel vs alu tanks Quote: (Originally Posted by n2diving) ... As a practical matter, the AL13's with two 2 lb trim weights (total for 4 lbs) is the best solution for most divers. The AL20's are the best solution for divers who want more gas. These trim out nicely regardless of diving wet or dry. I've got several sets of used LP27's and used HP13's gathering dust if anyone is interested, but the price would be no bargain. -- Mark Hi Mark - inadvertently tying this thread to your other posts about the revised EAC duration relative to CO2 absorbed/O2 consumed (apologies for going partially off-topic), do you have the specs on the capacity in liters/internal volume of the AL20s? I have the info for the 13s and I believe you explained that, as well; but I can't find the same on the 20s. Trying to establish what psi used equates to 240 liters of O2 in the 20s ... Many thanks in advance, __________________ Cheers, John Cogan
(Online)

12th August 2007, 20:32	#8 (permalink)
n2diving Custom Title Allowed! Current Rebreather/s: Optima Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Feb 2005 Location: Florida, USA Posts: 271	Re: steel vs alu tanks The AL20's are rated at 20 cu ft @ 3000 psi... I don' t have the water volume, sorry.
(Offline)

12th August 2007, 20:38	#9 (permalink)
zmcave www.rebreather.com.br Current Rebreather/s: Optima Dolphin Other Rebreather/s: Optima Dolphin Join Date: Apr 2006 Location: Brazil Posts: 186	Re: steel vs alu tanks Quote: (Originally Posted by JCdesign97) Hi Mark - inadvertently tying this thread to your other posts about the revised EAC duration relative to CO2 absorbed/O2 consumed (apologies for going partially off-topic), do you have the specs on the capacity in liters/internal volume of the AL20s? I have the info for the 13s and I believe you explained that, as well; but I can't find the same on the 20s. Trying to establish what psi used equates to 240 liters of O2 in the 20s ... Many thanks in advance, The 20cf rated at 3000 has 2.7 liters of volume. So, if filled at 3000 psi, 207 bar, it will have a total of 540 liters. Down here we don't boost O2, so we usually get about 2400 psi, 160 bar, and thats a total of 432 liters. To try answer your question, the 240 liters of O2 in a 20cf tank is about 88 bar of use, or something like 1300 psi. hope it helped. Zé.
(Offline)

12th August 2007, 21:58	#10 (permalink)
JCdesign97 My unit can beat up yours Current Rebreather/s: Optima Other Rebreather/s: Join Date: Mar 2007 Location: PA, USA Posts: 382	Re: steel vs alu tanks Quote: (Originally Posted by zmcave) The 20cf rated at 3000 has 2.7 liters of volume. So, if filled at 3000 psi, 207 bar, it will have a total of 540 liters. Down here we don't boost O2, so we usually get about 2400 psi, 160 bar, and thats a total of 432 liters. To try answer your question, the 240 liters of O2 in a 20cf tank is about 88 bar of use, or something like 1300 psi. hope it helped. Zé. Obrigado Ze, perfect - much appreciated! __________________ Cheers, John Cogan
(Online)

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