Bailout Bottle Test

[fundiver12]

I know there has been discussion after discussion on here regarding which is better...Spareair or pony bottle. Each have pro's and con's. The general comments about Spareair is that it doesn't provide enough air to do a safety stop and requires you to ascend at the maximum 60fpm rate. On the other hand the pony bottles give you more versatility, more air, and provide the ability to ascend at a safer slower rate. However, the pony bottle weighs more, promotes bouyancy issues, and requires you to buy an additional 1st and 2nd stage, so you'll therefore have more hoses hanging off of you.

I recently read an article in the April 2004 Scuba Diving magazine that gave details on a test that was recently completed by Rodales. I would encourage you guys to read it. Although I don't believe everything I read, I thought the article was interesting. It basically stated that they were able to ascend safely from 70 feet to the surface and still had about 6 or 7 breaths left in the 3CF spareair bottle, while pretending to be in a state of panic, (i.e., breath rate of 2.1). Most people claim that normal breathing renders around 1.67. So I would agree that carrying spareair is a good option if you are not diving below 70-80ft. I realize a lot of people say that having a bailout bottle provides a false sense of security, and I would agree that could be the case for some. But a lot of folks buy a pony bottle then never use it, because if you go on a trip, it you must disassemble it to fly with it, and its added weight. Would probably be better to have something lightweight and be willing to carry it, than to carry nothing because of the inconvenience.

You can buy the 3CF spareair kit for around $200 on leisure pro. My pony setup cost me around $300, so the popular belief that spareair is more costly than the pony setup is a pipedream.

Happy diving.

 

[CRDiver]

$200 for 3cf of air, versus $300 for a 19cu ft setup, like I carry?.... over 6 times the amount of hair for a hundred bucks more? It IS cheaper for those who can do math! And trim isn't an issue for experienced divers.

 

[padiscubapro]

I know there has been discussion after discussion on here regarding which is better...Spareair or pony bottle. Each have pro's and con's. The general comments about Spareair is that it doesn't provide enough air to do a safety stop and requires you to ascend at the maximum 60fpm rate. On the other hand the pony bottles give you more versatility, more air, and provide the ability to ascend at a safer slower rate. However, the pony bottle weighs more, promotes bouyancy issues, and requires you to buy an additional 1st and 2nd stage, so you'll therefore have more hoses hanging off of you.

I recently read an article in the April 2004 Scuba Diving magazine that gave details on a test that was recently completed by Rodales. I would encourage you guys to read it. Although I don't believe everything I read, I thought the article was interesting. It basically stated that they were able to ascend safely from 70 feet to the surface and still had about 6 or 7 breaths left in the 3CF spareair bottle, while pretending to be in a state of panic, (i.e., breath rate of 2.1). Most people claim that normal breathing renders around 1.67. So I would agree that carrying spareair is a good option if you are not diving below 70-80ft. I realize a lot of people say that having a bailout bottle provides a false sense of security, and I would agree that could be the case for some. But a lot of folks buy a pony bottle then never use it, because if you go on a trip, it you must disassemble it to fly with it, and its added weight. Would probably be better to have something lightweight and be willing to carry it, than to carry nothing because of the inconvenience.

You can buy the 3CF spareair kit for around $200 on leisure pro. My pony setup cost me around $300, so the popular belief that spareair is more costly than the pony setup is a pipedream.

Happy diving.

Rodales has traditionally given favorable exposure to active advertisers.. So their opinions should be viewed with this in mind.. It wouldn't be in thier best interest to rip a product that is from a big advertiser.

this topic has been beaten to death many times.. 3cf is nothing.. 60fm is not the recommended ascent rate 30fpm is..

that means it takes 1 minute to ascend between 70 and 40 ft for an average depth of 55 fsw (2.67 atas) with a very reasonable rmv of 1.0 cuft/min that means you need 2.67 cuft of gas to get to 40 ft..

now we will take .67 minutes to get to 20 fsw (average depth 30 fsw or 1.9 atas) that means you need another 1.27cuft to get to 20 feet.. ooops you are out of gas..

to do a 3 minute safety stop (1.6 atas) you need 4.8 cu ft and finally .67 ascent to surface avg depth 10 fsw (1.3 atas) or .87 cu ft of gas..

the total required is.... 2.67+.1.27+4.8+.87=9.61 cuft of gas, a panicked diver is probably more like 1.5 cuft per min or greater..14.4 cuft+, at 80 fsw your requirement is a bit higher

Those who use the ANDI or NASDS ascent procedures would require even more gas..

The only thing a spare air is good for is to prevent an ESA, if you are going to bother spending the money and carrying something you should use the right tools.. not something thats basically a pipe dream..

All the above assumes you can immediately go to the surface.. There are many areas where you MUST go up and down an ascent/descent line.. it could take you several minutes to get to this point, you would be out of gas before you even got to the line..
The following recommendations are for a diver in control
13 cuft is adequate for about 80 fsw, 19 cuft about 100, and 30 cuft for about 130.. someone with a higher RMV would have to adjust these sizes.

 

[DrMike]

You can buy the 3CF spareair kit for around $200 on leisure pro. My pony setup cost me around $300, so the popular belief that spareair is more costly than the pony setup is a pipedream.

Happy diving.

It is more costly - as in its more likely to cost you your life!

 

[MikeC]

The following recommendations are for a diver in control
13 cuft is adequate for about 80 fsw, 19 cuft about 100, and 3 cuft for about 130.. someone with a higher RMV would have to adjust these sizes.

Do you mean 30 cuft for the deeper depth???

 

[padiscubapro]

Do you mean 30 cuft for the deeper depth???

Thanks I edited my last post..

 

[pipedope]

Sorry.

The spare air is a great unit and you should ALWAYS carry one.
...
...
In a pocket of your mustang suit for the helo ride over water to the offshore rig.

For diving, a pony bottle of reasonable capacity is a much better choice.

 

[neophytediver]

I read the article and found the results to be highly suspect. First of all there is no way to simulate a panicked diver because every diver panicks differently. Everyone breathes at different rates, whether excited/stressed, everyone breathes different volumes of air per breath, etc. While I enjoy Rodales as a magazine I personally never put any faith in anything they test. Usually it's just a case of having enough money thrown at them to get a good review.

 

[-hh]

I recently read an article in the April 2004 Scuba Diving magazine that gave details on a test that was recently completed by Rodales. I would encourage you guys to read it.

Done. IIRC, I noticed that they didn't document their test divers' SAC's. As such, the article is nearly worthless for me to use it to quantitatively compare their analysis with my own.

But a lot of folks buy a pony bottle then never use it, because if you go on a trip, it you must disassemble it to fly with it, and its added weight.

The DOT CFR regulations (DOT 49 CFR 173.115) for air travel apply equally to both devices...the SA gets no "break" here. On weight, it saves ~6lbs in your luggage, but before claiming that as significant, try weighing a couple of your current travel suitcase completely empty for a rude little surprise in "overhead".

You can buy the 3CF spareair kit for around $200 on leisure pro. My pony setup cost me around $300, so the popular belief that spareair is more costly than the pony setup is a pipedream.

If we continue to compare apples to apples and use Leisure Pro for pricing, their pony tank is $75 (w/valve), plus a Mares R2 Axis Regulator for $115,which sums to $190, thus leaving you $10 to DIY a sling to stay within the $200 budget.

Besides, if you've ever upgraded your regulator, you have your old reg laying around and msot people would claim that that is "Free", so the SA price can actually be beaten, depending on your individual circumstances.


IMO, the SA is a great $50 tool. Too bad it doesn't cost $50.

-hh

 

[lamont]

What are the use cases where people actually have used pony bottles or spair air? I can think of a few, ranging from someone who doesn't notice their tank is dry and just needs a few breaths to get to the surface, to someone who needs to search for a lost buddy who may be entangled, narc'd or otherwise in trouble and where the searcher may be pushing NDLs or going into deco.

The real argument to have here I think isn't over the math of how much air you use at a given depth, but in accident analysis.

Here's a post I made a few days ago though in the last pony/spair air argument thread which has a couple of tables of gas consumption to reach the surface from a given depth, given some different assumptions:

http://www.scubaboard.com/showpost.php?p=553252&postcount=265