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FreedomPC
04-11-2008, 09:39
I'm looking for a refillable backup air system that's small and easy to use. My fiance is a little nervous when we dive deeper than 50'. She told me that if she had something like this she would be more comfortable. I tried talking her into a pony but she wasn't having it :smiley36:. So it looks like I'm in the market for a spare air. Thanks.

terrillja
04-11-2008, 09:43
I'd read this:
http://forum.scubatoys.com/tanks/10435-problems-spare-air.html

For about the same cost as a Spare Air, you can get a pony and reg with 30x the air.

mentalmarine
04-11-2008, 09:43
Cant help ya on the spare air, but I like your avatar! At least ya got your fiance in the water :) I am still working on mine.

skdvr
04-11-2008, 09:49
You should reconsider trying to talk her into the Pony. Have her get on here and do some reading and I really think she would go with a small pony. Even a little 13 cu ft woule be better than a spair air.

Just my opinion...

Phil

frogman159
04-11-2008, 10:01
Let say your using an AL80 filled to 3000psi (full)

Lets assume you dive to 60ft and this dive lasts you ~45 minutes when your tank hits 500psi

You used up about 66.67 cf of air in 45 min or 1.48cf/minute!

A spare air is 1.7cf and if you need to use it your likely stressed.

The point is I wouldn't expect that 1.7 cf spare air to last you more than 1 minute of stressed breathing.

Now factor in a deeper depth and the time your spare air will last will go down even further, If that doesn't convince her, its a waste of $200, not sure anything will..Get out the credit card:smiley2:

mwhities
04-11-2008, 10:10
Let say your using an AL80 filled to 3000psi (full)

Lets assume you dive to 60ft and this dive lasts you ~45 minutes when your tank hits 500psi

You used up about 66.67 cf of air in 45 min or 1.48cf/minute!

A spare air is 1.7cf and if you need to use it your likely stressed.

The point is I wouldn't expect that 1.7 cf spare air to last you more than 1 minute of stressed breathing.

Now factor in a deeper depth and the time your spare air will last will go down even further

I concur; very well said. If that doesn't change her mind, you better pack an al80 with a 40"+ hose for air share with her.

FreedomPC
04-11-2008, 10:30
Thanks for all the input. I forwarded all the messages to her. I think she is going to consider the pony with a 2nd reg. Of course when I suggested something like this she wouldn't hear it.

No Misses
04-11-2008, 10:41
If she is dead set against carrying a pony, get her the spare air.
I have a pony that I carry on deep dives or when I dive an AL80 instead of my HP120.
A pony does you little good if you are unwilling to carry it. If she will carry the spare air on every dive, it is better than a pony that she will not carry.
With all of that being said. I prefer the pony over a spare air. Spare air units come in 2 sizes 1.7 cf and 3 cf.

I have attached a spreadsheet that calculates your minutes of breathing gas at depth for different sized cylinders. All you do is enter your SAC, Pony size, & depth.

FreedomPC
04-11-2008, 11:00
Thankx. I read a previous message from you that had a basic chart. This is much better. I think she will carry the pony. She is more concerned about running out of air than having to carry something else. Her main concern was if she ran out of air started to panic and grabbed the octo instead of the pony reg. She said that if it didn't have a hose she would know it was the right one. Like I said she is still pretty nervous at this point.

MSilvia
04-11-2008, 11:00
Lets assume you dive to 60ft and this dive lasts you ~45 minutes when your tank hits 500psi.

A spare air is 1.7cf and if you need to use it your likely stressed.


:2cents:
Not that I'm advocating for the Spare Air (I'm not... I think it's ridiculous that they market them to divers), but in this particular scenario the diver still has 14.6 cubic feet of gas to get to the surface with. Out of air would be a totally different story but if you have 500 psi left in an 80 cubic foot tank, you aren't out of air yet. You can still get a lot of breathing out of an 80 cubic foot tank that's 16.7% full.

Just a nit pick, but don't go drowning with air on your back just because your backup ran out.

frogman159
04-11-2008, 11:08
Lets assume you dive to 60ft and this dive lasts you ~45 minutes when your tank hits 500psi.

A spare air is 1.7cf and if you need to use it your likely stressed.


:2cents:
Not that I'm advocating for the Spare Air (I'm not... I think it's ridiculous that they market them to divers), but in this particular scenario the diver still has 14.6 cubic feet of gas to get to the surface with. Out of air would be a totally different story but if you have 500 psi left in an 80 cubic foot tank, you aren't out of air yet. You can still get a lot of breathing out of an 80 cubic foot tank that's 16.7% full.

Just a nit pick, but don't go drowning with air on your back just because your backup ran out.

:smiley5:
I used the that 500psi in an AL80 scenerio to calculate a minute air consuption volume, using figures that the OP may relate to.

I wasn't saying you'd use a spare air if you had 500psi in your AL80:smilie39:

frogman159
04-11-2008, 11:10
That is unless both your regulators were shot, and you couldn't find your buddy...Which is another issue all its own

MSilvia
04-11-2008, 11:33
I wasn't saying you'd use a spare air if you had 500psi in your AL80:smilie39:
I figured as much, but since I've seen DMs be VERY strict with new divers about getting back to the boat with x amount of gas, I just thought I'd point out the obvious.

That is unless both your regulators were shot, and you couldn't find your buddy...Which is another issue all its own
Yeah, I think a solo free ascent while sipping directly off the tank valve is beyond the scope of the discussion. You'd definately score some points for getting yourself out of that one, but no more than you'd lose for getting into that situation in the first place.

terrillja
04-11-2008, 11:37
Yeah, I think a solo free ascent while sipping directly off the tank valve is beyond the scope of the discussion.
But they did it in into the blue... Does that mean people don't usually do it? Guess I'll have to figure out a new way to rescue women from coke filled planes.

texdiveguy
04-11-2008, 11:37
I'm looking for a refillable backup air system that's small and easy to use. My fiance is a little nervous when we dive deeper than 50'. She told me that if she had something like this she would be more comfortable. I tried talking her into a pony but she wasn't having it :smiley36:. So it looks like I'm in the market for a spare air. Thanks.

Save your $$.

Get what is the right gear for this task of a redundant gas source...the Spare Air is not it!

frogman159
04-11-2008, 11:56
[quote=MSilvia;156378]
Guess I'll have to figure out a new way to rescue women from coke filled planes.

:smilie39::smilie39::smilie39::smiley20::smiley20: :smiley20:

Sounder
04-11-2008, 14:07
Freedom - go to the following website, read everything that is there, then read it again following along with your calculator... then I'd suggest applying it to your diving.

Rock Bottom and Gas Management for Recreational Divers (http://www.scriptkiddie.org/diving/rockbottom.html)

Stay within these bounds and the other diver will ALWAYS have your "pony/spare/whatever" on their back waiting for you.

There is a saying, "Spare Air... so you can run out of air TWICE!!" I had someone offer me an opportunity to try one... so I took them up on it. 50 breaths at the surface is fine, but remember how fast the volume of gas you require increases with depth. 50 "breaths" at the surface means 25 breaths at 33fsw, or 16 breaths at 66fsw, or 12 breaths at 99fsw, etc. How much is a breath? Do my wife and I use the same volume of gas in each breath? Nope.

When I tried it, the regulator breathed extremely hard - I had to suck/pull every breath out of that bottle with as much force as I could (even when it was full). Secondly, I only got 7 breaths from it at 66fsw... far below what they claim it'll give you (it was their large model). So you take stress, add it to a regulator that you have to WORK to get the breath out of, and combine that with the possibility of the bottle not being full to begin with, and in my opinion, you've got a bright yellow false sense of of security.

I would highly recommend you take the money you'll spend on whatever system you're looking at, and find an instructor who will work with you on great buddy skills, emergency procedures, mid-water ascents while sharing, etc. Maybe put it into getting larger tanks so you'll have more gas with you on each of your dives?

Just my 2psi.

frogman159
04-11-2008, 17:15
Thats interesting you mention the number of breaths, at rest, a normal person breathes approx~12 times per minute out of the water, Under stress that number can easily double.

Sounder
04-11-2008, 17:24
Their website says a "breath" is 1.6 liters/breath. I suppose that's their disclaimer for "Your Mileage May Vary."

scubasamurai
04-11-2008, 17:28
I wasn't saying you'd use a spare air if you had 500psi in your AL80:smilie39:
I figured as much, but since I've seen DMs be VERY strict with new divers about getting back to the boat with x amount of gas, I just thought I'd point out the obvious.

That is unless both your regulators were shot, and you couldn't find your buddy...Which is another issue all its own
Yeah, I think a solo free ascent while sipping directly off the tank valve is beyond the scope of the discussion. You'd definately score some points for getting yourself out of that one, but no more than you'd lose for getting into that situation in the first place.


i think the dm's are just trying to teach the "new"divers about air management. simple because it is something new and might "forget" to look at their gauges. this way they know people will be checking their pressures at the boat so they keep a closer eye on their air

for me a simple 9 even a 13 will be good for deep dives over 60 ft. anything to me less than 60 ft is a waste to carry a pony, unless cave/caven/ or sink diving because of the low vis and other points.
get the pony, spare air gives you a small sense of security

zider
04-26-2008, 15:31
Agreed don't mess with the spare air. Try the zeagle backup system. You can use the 6 cuf tank that comes with it or swap it between the 6 and a purchased 13 like I do. Works great!!

Largo
04-27-2008, 11:51
Agreed don't mess with the spare air. Try the zeagle backup system. You can use the 6 cuf tank that comes with it or swap it between the 6 and a purchased 13 like I do. Works great!!


Careful! On this forum, if you say that you use anything smaller than a 20 cu ft pony bottle, a swarm of posters will descend upon you and say nasty things about you. :smilie39:

Babster
04-27-2008, 12:04
:smiley32: Truer words..... :smilie40:

As a matter of fact, I've figured I'm going to get the Zeagle system in the near future. I figure I'd use the little bottle for quarry/warmwater dives, and if I do Atlantic diving, I can use the regulator on a bigger pony bottle. So there.

dinger340
04-27-2008, 16:40
Dive Shop (http://divesales.com/index1.html?target=d7.html)

Has anyone heard about or had any experience w/ the "Air Buddy Bottle"? I have an Air Buddy regulator on my BC low pressure inflator as a third source of air and have used it in a pool w/ mixed results...

obrules15
04-27-2008, 21:17
Dive Shop (http://divesales.com/index1.html?target=d7.html)

Has anyone heard about or had any experience w/ the "Air Buddy Bottle"? I have an Air Buddy regulator on my BC low pressure inflator as a third source of air and have used it in a pool w/ mixed results...

There is a another thread here that comments on this and if I remember correctly the majority of the comments were none too positive.

MWD_Dave
04-30-2008, 17:31
Wow, not many people speaking positive for the Spare Air. I suppose I might get ranted at but here goes... ;)

First off, depending on what your doing, a pony bottle can be to big and bulky for an add-on. I'd probably haul one with me if I was wreck or cave diving, but if I'm just bottom cruising or something where "up" doesn't have a lot of obstructions, then I'd consider the 3 cft Spare Air.

Personally I use mine when I'm skin diving sometimes, and it's been great for that. But I'll admit I've never used it over 60ft so I can't give a review to it's performance at that depth. (A new project this summer. ;))

huvrr
05-05-2008, 00:32
I would recommend getting her whatever makes her more comfortable in the water.

DollFin
05-05-2008, 00:56
Their website says a "breath" is 1.6 liters/breath. I suppose that's their disclaimer for "Your Mileage May Vary."


That's like saying 2 cookies = 1 serving! :smilie39: