Roman_66
Contributor
Doubles or side mount are different courses, not sure that TS passed them and know how to use.
Also in some places doubles just not allowed, but pony 30cu is.
Pony bottle questions
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Also in some places doubles just not allowed, but pony 30cu is.
Can anyone help me understand the volume that you are talking about? For me A cubic foot equals to 28 liters. So 30 equals to a HUGE volume. CAn anybody tells me what a 30 cft bottle is in Liters? Thanks 
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LowDrag
Contributor
Can anyone help me understand the volume that you are talking about? For me A cubic foot equals to 28 liters. So 30 equals to a HUGE volume. CAn anybody tells me what a 30 cft bottle is in Liters? Thanks
According to Google when asked to convert 30 ft to liters the answer is 849.505 liters.
30 cf would be the volume of air contained in the bottle at 1 ATM, not the size of the bottle itself, which, without looking it up, would be in the neighborhood of 4 L.
Roman_66
Contributor
It is funny US system, when specification shown amount of gas not with 1 ata, but with recommended pressure and real tank size named "water" volume.Can anyone help me understand the volume that you are talking about? For me A cubic foot equals to 28 liters. So 30 equals to a HUGE volume. CAn anybody tells me what a 30 cft bottle is in Liters? Thanks
For example LP85DVB has bigger "water" volume than FX100DVB
Just see specification. AL30 has 30 cu ft with 3000 psi or 4.2 liters
Correct ! But it is under 207 bar, so"water" = metric size will be : 849.5 / 207 = 4.10 liters, why specification says 4.2, I have no idea. Maybe they have private "cu" or private "liters"
In some boat dives, for example Flow Garden trip doubles "not allowed" as well as pony bigger than 30cu.
Of cause every one can use any new equipment without any courses (side mount/back doubles/dry suit), but I prefer to learn first.
For example - my double certification:
Do you think that person, who first time wear double will know how to switch to one tank in case of leak from other ?
"want to live, will deal" may not work under water for first time.....:-(
Basking Ridge Diver
Contributor
I wear a 19 cu ft slung. I can see it, hand it off and at 130 feet I can get to the surface. It is small enough / lite enough that I carry it all the time. You need to know your RMV / SAC to determine your needs at depth - as well as your risk level.
My only thoughts are the more you dive the less air you need and if you are talking recreational diving (less than 130ft) - a 19 cu ft should fit most of your needs. A 30 cu ft or greater is heavier and your more likely to leave it on the boat or shore for those "short" dives...
I do not carry a pony for more than one person's air reserves and every contingency out there - if I did I might recommend slinging an 80 cu ft...
My only thoughts are the more you dive the less air you need and if you are talking recreational diving (less than 130ft) - a 19 cu ft should fit most of your needs. A 30 cu ft or greater is heavier and your more likely to leave it on the boat or shore for those "short" dives...
I do not carry a pony for more than one person's air reserves and every contingency out there - if I did I might recommend slinging an 80 cu ft...
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flots am
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Can anyone help me understand the volume that you are talking about? For me A cubic foot equals to 28 liters. So 30 equals to a HUGE volume. CAn anybody tells me what a 30 cft bottle is in Liters? Thanks
In the US, cylinders are rated according to how many cubic feet of 1-atmosphere air they contain, when pressurized to their rated pressure.
For example, if you took a 19 cuFt cylinder at 3000PSI and emptied it into giant trash bag at sea level, the interior volume of the trash bag would be 19 Cubic Feet.
flots
I back mount a 19 CF, and really can't even tell it's there. I recently went to a BP and Wing, because I like to take pictures (I'll stop short of calling myself a photographer ). The reason I went BP And Wing, is I wanted to free myself from having gear and "jacket" on my sides and front, and therefore don't want to sling. I like just having the pony 2nd stage on a necklace , makes me feel much more maneuverable.
I would also recommend doing some reading on "rock bottom gas management" and plan your pony around the type of diving you are doing. For me 19cf seemed to be the sweet spot, for enough air, able to complete a safety stop , and manage it's size along with camera equipment. (Most dives not deeper than 100, always with a buddy, etc)
). The reason I went BP And Wing, is I wanted to free myself from having gear and "jacket" on my sides and front, and therefore don't want to sling. I like just having the pony 2nd stage on a necklace , makes me feel much more maneuverable.I would also recommend doing some reading on "rock bottom gas management" and plan your pony around the type of diving you are doing. For me 19cf seemed to be the sweet spot, for enough air, able to complete a safety stop , and manage it's size along with camera equipment. (Most dives not deeper than 100, always with a buddy, etc)
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