Spare Air & Pony Tank

[RichLockyer]

I think that we can all agree that the Spare Air must be limited to less than a 90' and no OH enviroment!

What do you think?

At any depth where the Spare Air can safely get you to the surface, you are easily within the range of a CESA.

IOTW, no, 90ft is too deep for the Spare Air. Try something more like 40ft.

I know that you can (and probably have) test the Spare Air under controlled conditions and it works fine (if you consider blowing off a safety stop "fine"), but when the stuff hits the fan, your breathing rate will double. You're going to be at 90ft and your 1st stage is going to freeze, or you're going to blow a burst disk or a tank neck o-ring... or some other failure that is either going to make a LOT of noise and bubbles, which will scare the crap out of you, or it is simply going to stop delivering air... you're going to discover this after you have exhaled... not right after a full inhale, which is commonly how a "drill" is run.
You're going to fumble with the thing getting it out of it's holster. Hopefully you don't lose focus and drop in the water column... remember, you've exhaled, so if you were neutral, you are now slightly negative.

Okay... so now you want to make a safe ascent. From 90ft, at 33fpm, that means that you have 3 minutes to make the surface, ignoring the safety stop.
90ft to the surface is an average depth of 45ft. That's a pressure of 2.36 ATA. Assuming that your SAC is going to rise to 1.0 CFM (it could go as high as 2.0 if you are really spooked), then you are going to burn 2.36 (SAC) * 3 (ascent time) = 7.08 cubic feet of air for that ascent.

Adding a safety stop is going to add another 3 minutes at 1.45 ATA. An OOA situation SHOULD NOT be an emergency requiring one to blow off a safety stop... especially not from 90ft. Assuming that you're calmed down and back to your normal breathing rate, then PERHAPS you can make that safety stop on another 2.5 cubic feet. You're now up to about a 10cf requirement, for a bare minimum, truly safe ascent from 90ft.

That 6cf Spare Air is not going to be enough, and this is assuming that you can begin the ascent as soon as you take your first breath.

In a panic situation, that 6cf will last you 6 minutes at the surface. At 100ft, it'll last you 1.5 minutes... maybe.

At the bare minimum, for dives to 100ft, you should be carrying a 13cf pony... and I wouldn't go deeper than 100ft on that. The deeper you go, the more important it is to do that safety stop. Yes, bent you can treat, dead you can't, but why worry about either one? Add to that the fact that you can buy a 30cf tank and basic reg (the Titan is a decent reg) for the same price as a Spare Air....

The 30 would be enough to get you AND a buddy up from 100ft... or enough to get YOU up from 130ft with time for an easy 5 minute safety stop.

 

[RichLockyer]

There is actually one good use for a Spair Air: strapped to your back on a deep free dive. Therefore, I would only use a 20+ cf pony slung as a stage bottle above 130 feet, and doubles below that.

A 20 is too short to sling as a stage. 30 is a minimum, but a 40 is best. Remember, the distance from the neck to the band that secures the lower end of the sling is equidistant to your left shoulder and left hip D-rings.
The S19 is 18" long. That happens to be EXACTLY the distance between the D-rings on my harness, which means that the band would have to be at the very edge of the tank, and on the verge of falling off. The 30 is 22" and the 40 is about 24.5.
It also remains negative until completely empty, so the end of the tank will not float up and out of the slipstream, tucked under your arm. The 30 and 40 both swing fully positive before they are down to half, but most importantly, they balance butt-light, so even when full, the tail will ride up under your arm.

The Spare Air was designed as a bailout bottle for helicopter pilots.
It works for that. It is totally unsuitable for any type of diving.

Under what conditions would you use it when freediving? If you become entangled in line or kelp, you are probably going to need more than it can provide to cut yourself free. It might be the difference between life and death, but I would not count on it.

 

[RichLockyer]

The only down side of the pony bottle, is the added cost due to bigger bottle, extra 1rst & 2nd stages, attaching hardware, ect. and the larger profile that it creates.

How much was your Spare Air? $250?
You can get a Luxfer 30 for about $100, and an Aqua Lung Titan or Calypso for another $120.

This is all from my LDS... you can do better online.

 

[teknitroxdiver]

Remember this about the pony bottle size: you might as well get a big one. You've already spent a good deal of money to get to, say, a 13cf bottle, but for very little more, you could have a 30 or 40. And it doesn't increase your profile if you sling it.

About the freediving: I would rather have a little help if I did need it, even if the bottle might not last long enough to get cut out, it would still help a whole lot. And, if you misjudged your freediving ability and found yourself too deep, just pop out the spare air and head up nice and easy.

 

[Mandy3206]

Very informative Rich

 

[pmartin2237]

Just a short reply to Stingray 1. Stingray, I've been diving since the late 60's (before BCD's and etc.) and I mainly dove solo. In the early 90's I decided I wanted to be more in control of my own fate and went back to solo diving mainly because of several bad incidents with the buddy system. I went and researched the subject as much as I could but there just wasn't much out there back then other than the psychological side of it (remember no nifty browsers to surf the internet, everything was done with out a GUI). Anyway, I then set my own requirements and being redundant was one of the requirements and it would give me an extra margin of safety, hence the pony bottle & spare air. I also carry not only a knife but also a pair of snips just for those fishing nets and line people leave behind.

I sail solo and most of my communication, navigation and location systems are redundant. So, bottom line, each to is own and having a spare air in addition to my pony bottle is my decision and has nothing to do with any diving experience. If you ever get caught in a bad situation hindsight isn’t going to do much for you.

 

[stingray1]

Just a short reply to Stingray 1. Stingray, I've been diving since the late 60's (before BCD's and etc.) and I mainly dove solo. In the early 90's I decided I wanted to be more in control of my own fate and went back to solo diving mainly because of several bad incidents with the buddy system. I went and researched the subject as much as I could but there just wasn't much out there back then other than the psychological side of it (remember no nifty browsers to surf the internet, everything was done with out a GUI). Anyway, I then set my own requirements and being redundant was one of the requirements and it would give me an extra margin of safety, hence the pony bottle & spare air. I also carry not only a knife but also a pair of snips just for those fishing nets and line people leave behind.

I sail solo and most of my communication, navigation and location systems are redundant. So, bottom line, each to is own and having a spare air in addition to my pony bottle is my decision and has nothing to do with any diving experience. If you ever get caught in a bad situation hindsight isn’t going to do much for you.

I'm glad for your experience and # of years diving. Good to still have you with us. You can search the intro and greets and for that matter any post that I have made and from the numerous posts you will discover a great deal about me and the way I dive. Mainly that I taught myself and I too learned from the start about redundancy. It was something that I did not need to be taught about when I finally received a c-card. I in fact learned very little from my instructor and my pockets were a lot lighter as the result. But we're not all Jacque Custo either. I just feel that your creating unnecessary entanglement hazards for yourself and over burdening yourself in the process of being redundant. What's the spare air going to do for you that a good 13 to 40 cf can't? Hell, why not go further and strap on a couple of 80 cf stage bottles. I'm not the super diver out there and will never claim to be. But I don't see any reason on "over burdening" myself with extra gear that is unnecessary. Dive with what is necessary for the current and particular dive at hand and leave the rest. I have lots of gear but I don't dive with all of it at one time. I take what is needed and possibly needed and nothing else. I can just see myself with a sled carring all the tanks and gear that I can not get slung to me for a dive to 90 or 100 ft. lol. Dive safe, dive smart is all that I'm saying because, in the end, your going to do what ever it is that you want to do anyway, just the same as anyone else.

Norm

 

[Chris Bangs]

Hi All new the the board


I am a pro photographer, therefore, solo diving is a way of life!

in reality, unless you are a student in a course with an instructor present, every dive should be considered a solo dive. Look at it this way, do you feel comfortable driving a car without a spare tire? Most likely not as a flat would be a pain to deal with. Well then your should not dive without a second separate supply since it a life support system and not just a convenience.

I use a redundant air supply on any dive planned to be more than 30 feet ( that means the bottom is less than 30 ft deep ) even if I am diving with other folks. My wife as well uses a redundant air supply and she always dives with me or someone else

Two is one and one is none!

Regarding the Spare Air, it was designed for Helicopter pilots to use in case of a unscheduled landing in the drink. It used to be the standard but it has or will be soon replaced with a system that allows the user free use of both hands, kinda like a pony bottle, Eh! Anyway, aside from it's very limited air supply the design that requires you to constantly hold it while in use in a major drawback.

As for the price if I remember, Spare Air systems are not cheap. I would guess that a new Pony 16 to 30 cu/ft and a basic entry level ( nothing fancy required ) reg . 1st, 2nd. and psi gauge. will cost about the same.

you can also consider getting a cheap used reg and having it overhauled to make it new again. You should also ask you service tech to adjust the 2nd stage as if if were an octo so it will not free from. I use an old adjustable second stage which is even better as it wont free flow and if I need to use it I can set it to perform like a primary 1st stage.

I mount my pony on my tank using a special bracket and then connect the second stage to my harness like a normal octopus.

I travel a lot and taking a bottle with me is now a pain in the butt. Therefore for on the road I use the dive rite strap type tank mount. and a BCD tank strap. This allows me to use a standard size tank as a redundant air supply ( poor mans doubles ) here in Japan where they will not fill my DOT Pony bottle and tank rental is ridiculous. I use a equalizer hose assemble that allow me to fill the pony using another tank. I know shame on me but I am certified to VIP tanks.

anyway, Get a redundant air supply and get a pony bottle, as I consider the Spare Air as something that is only decorative!

Sorry to babble

Chris

 

[rjchandler]

I use a equalizer hose assemble that allow me to fill the pony using another tank. I know shame on me but I am certified to VIP tanks.



Chris

Noe shame - most people who travel w/ pony bottles end up doing somethin like this. a c-card to do VIPs??

 

[Chris Bangs]

No C-card! just a piece of paper in a frame proving that I took and passed the PSI course. I worked in the dive biz on Guam for 10 years just a little fringe benefit.