pony or spare air?

[Dwndiver7]

With the proper adaptor, spare airs are great for filling balloons at your childs birthday party.

A pony bottle is merely a fire extinguisher. You keep it under the kitchen sink for years and years. When you need it, it's there. But... you certainly don't fool yourself into thinking it will put out a house fire. It's a small tool you hope you never need.

Now, as far as an exstension of air supply for "super suckers".... what idiot would strap on a second small tank when they could just start out with a steel 120?

And for all the calculating and factoring of risk assessment... truly, your intellect is dizzying.

 

[Scott-D]

Thanks for that thoughtful post! It's easy to lose sight of the concerns that we all had in our early days of diving.

One last point. This thread was started about the situation of a new diver with a high SAC needing an RAS. I think that the best way to do this sort of analysis is to forget about the air consumption issue.

The choice to use an RAS should be based on the type of diving, not the diver. In other words, if you are saying I need an RAS because I go through my air quickly, then you are missing the point. However quickly you use air, gas management should follow the same principals (e.g. rule of thirds, etc..). A new diver might run through their back gas more quickly than an experienced diver, but they both should have the same awareness of their remaining gas, dive time, depth contribution, etc...

Essentially, the RAS shouldn't figure into your gas management and dive planning, so it is just as useful (or perhaps in some cases, just as superfluous) for a newbie as for an experienced diver.

Oh, I agree and certainly wasn't saying nor suggesting any redundant air should be used for blowing thru your gas nor an excuse to use it for that purpose. Whether you go thru your gas at 10 minutes or 30, it shouldn't matter. You plan to be at the end of your dive at that time. My apologies if I gave the impression otherwise.

I guess what I was trying to say is I think new divers tend to look closer and at a "catch-all" RAS because they tend to go thru their gas faster than the more experienced, and because of that feel they have less opportunity to catch an error, and regardless of the training to get OW or even AOW they really don't know what to expect until they've had a few dives logged. At least I know I didn't & that's why I originally looked into a RAS for something to always carry on my dives (until you fine people educated me otherwise ).

Going off myself, my first 100' dive lasted all of about 13 minutes before I'd exhausted the planned air & started the ascent (SAC of about 1.1). Because the computer was showing me the remaining air time estimate and PSI's, remaining air was constantly on my mind. Every breath I saw the computer drop a bunch of PSI's and my estimated air just seems to disappear incredibly fast. I remember looking at my computer more than the waters around me I was so nervous about going thru my air & missing the turnaround & ascent marker. But after a few dozen dives the same depth now gets me 1) a lot more time as I'm better at gas management, therefore I know I don't have to constantly keep my eye locked on the guage and 2) I know a little better what to expect.

 

[Scott-D]

A pony bottle is merely a fire extinguisher. You keep it under the kitchen sink for years and years. When you need it, it's there. But... you certainly don't fool yourself into thinking it will put out a house fire. It's a small tool you hope you never need.

Love the fire extinguisher analogy. Just perfect.

Now, as far as an extension of air supply for "super suckers".... what idiot would strap on a second small tank when they could just start out with a steel 120?

And that's exactly why I'm buying steel 119's. More bottom time is a good thing!

 

[Groundhog246]

I love spare air. The utility of it is that it's small and allows you to ascend upon a first stage failure. Perfect for me. Had mine for over a year. Won't dive without it.

How many times have you used it? I just can't see doing a SAFE ascent and safety stop with the amount of air in a spare air. If you've carried it on every dive, but never used it, then how do you know it's perfect for you? If you've had it over a year, have you had it serviced per the industry norm of annual service for a regulator?

When my diving situation makes me desire a backup air source (example a dive to 90 feet), I carry a 30CF stage. I HAVE switched to it, ascended on it (practice, not emergency). I have unclipped and handed off to a buddy (again we were practicing, theory and planning needs to be backed up with practice).

Lastly, a freeflowing first stage, on an AL80, that let go anywhere above 1000PSI, will probably still be delivering air after your Spare Air has run out. I've emptied an AL80 from 800PSI to send for hydro and it's amazing how long it took to empty. My first experience with a free flow was a buddies reg at 50 feet. We ascended with him on his own reg and we were able to ascend and turn the cylinder valve off, well before the tank ran out, avoiding the cost of a viz.

 

[Groundhog246]

With the proper adaptor, spare airs are great for filling balloons at your childs birthday party.

Love it.

A pony bottle is merely a fire extinguisher. You keep it under the kitchen sink for years and years. When you need it, it's there. But... you certainly don't fool yourself into thinking it will put out a house fire. It's a small tool you hope you never need.

I get the analogy. However, I have a fire extinguisher on the wall of my kitchen with a current inspection tag and THREE on my boat, one on the pedestal, one in the Vee berth and one beside the engine compartment, also all with current inspection tags. Will they put out a major fire? NO. Will they put out a small fire, before it becomes a major fire, I hope so. Also, they're not the little 2.5lb jobs, the one on the pedestal is a 5lb and the rest, including the kitchen and 10lb. As for my pony bottle, it's 30CF, or slightly more than 1/3 of the AL80 I normally dive. I practice with it periodically, and it's kept up on vis and hydro, just like my other tanks. I don't use it to extend bottom time, I use it as a backup. In fact the dive shop where I got it, his first question was, WHY? I explained why and all was good, he told me after if I had mentioned increasing bottom time, he'd have declined to sell it to me.

 

[doctormike]

I don't use it to extend bottom time, I use it as a backup. In fact the dive shop where I got it, his first question was, WHY? I explained why and all was good, he told me after if I had mentioned increasing bottom time, he'd have declined to sell it to me.

Exactly!

Saying "I carry a pony to extend my bottom time" is sort of like saying "I keep a fire extinguisher around so that I can smoke around my open gasoline containers..."

 

[divingmoose]

PENITENT 1 { I haven't calculated my air use yet (SAC) (just finished my scuba certification). I suppose that I want to know if I should spend my money on redundant air or on a regulator or computer.

I like being under water. I think that having an extra source of air would make me feel a whole lot safer - you never know with rented gear.[/QUOTE]

As some one who has had air problems might I suggest that until you become a little more comfortable " Dive with an experienced buddy ,practice buddy air share" it has worked for me. As you practice you will become more comfortable. Trust your gear its all we got except your buddy. As a Newb Learn to do your charts but Practice makes perfect. Just a thought No air is Redundent if you need IT. Up grade your gear as you like. We started with regs and suits it your option. good diving.

 

[Dwndiver7]

I added a pony rig for solo diving. Same reason I carry 2 computers, 2 masks, 2 lights, 2 gloves, 2 fins... wait... I got ahead of myself.

The pony is there for many reasons (none of which ever enter gas/profile planning). But it is there mainly for the "holy schnikeys!"

There are more what ifs than any of us could ever conjure up. Bottom line is YOUR confidence in YOUR skill and YOUR gear. Keep it up to date (service/inspection). And practice with the set-up YOU are comfortable with.

Oh yeah... HAVE FUN! If diving doesn't put a poop eatin' grin on yer face... you ain't doin' it right!

 

[rsq_dvr]

I have a spare air and only use it on shallow dives (<20meters) for two reasons, 1) I dont think my SAC would be much good any deeper or for deco. 2) If something goes wrong, any help is better then none. Diving where I dive is hard to get a good fill and I want to pull my hair out everytime I go to get air. If I had a pony, that would just make the heavy brows here confused. (I use stage on deeper dives)

 

[Groundhog246]

any help is better then none. Diving where I dive is hard to get a good fill and I want to pull my hair out everytime I go to get air.

Thinking you have backup when you don't is even worse. And I'll ask my usual question. Have you tried an ascent with it? Most I've asked who carry one have never used it.
What's the issue with fills? If they have older compressors that have a hard time reaching 3000PSI on an AL80, consider picking up LP steels. Pick up some LP 95's or go huge with 120's and a few PSI short are much less concern. And if you can't get 3000PSI on you main cylinder, you aren't getting it on your spare air, which means a very small amount of air just got smaller.