Recreational Pony Bottles, completely unnecessary? Why or why not?

[lexvil]

To tired to read all of this since it’s pretty redundant but…

some presume a pony is to complicated for a newish diver to operate yet advocate that said same newish diver can handle doubles, same number of tanks and regulators but one tank being smaller.

more air isn’t better but more more air is…


In which proof scenario of doubles being better because more more being better than more would not a rebreather be better better?

 

[boulderjohn]

I'm a little confused with your question, would you like to go over proven gas laws and theories?

Not really, but to a certain extent it would help. You are insisting that the OOA team do a 9 minute ascent, and the reason for that has to come down to that sort of thing, doesn't it?

A couple years ago I worked with Dr. Simon Mitchell and published an an article on ascent profiles in decompression diving. That put me in touch with a lot of that research. I wanted to follow up with an article on ascent profiles on NDL dives, but Simon declined to participate--he said there is not enough definitive research, and he did not have an opinion. So I set out on my own, and I believe I read all the most recent research and decided that, like Simon, I could not form an opinion on an NDL ascent strategy. The general approach that has been used for more than 100 years is still the most thoroughly studied and proven.

That is why I contacted GUE and asked for an official explanation, as described above. They confirmed that the only physiological basis for the approach is their belief that the ascent should slow down when nearing the surface. They could cite me no research in support of that belief.

So I really do like to know scientifically why the min deco approach is so critical that it needs to be used during an OOA event.

The thought process is, that once the OOG diver has a working regulator in their mouth, the emergency is over but the dive must end. Thus, the divers go up on a slightly conservative ascent profile to factor in heavy SCR's and mitigate panic while also giving their bodies time to off-gas.

Outside of DIR circles, more than a century of research has indicated that if a diver within NDLs ascends at a safe rate, that alone is enough to off-gas. A few decades ago, safety stops were added to play it safe. So, using the theories 95% of the diving world uses, a diver ascending from 80 feet should be able to do so safely in less than 3 minutes. Add a safety stop, and you are at 6 minutes. Why should it take 9?

However, we normally do a "minimum decompression ascent" for rec dives.

E.g. Divide the depth by two. In the first half of the ascent, the travel rate is 9m/30ft per minute, and in the second half , the rate slows down to 3m/10ft per minute.

The second phase of the minimum decompression ascent, conducted at 3m /10ft per minute is usually performed as a series of punctuated stops maintaining overall ascent rates.

I know all that. Remember that I got the detailed explanation from GUE, and I was myself trained in the UTD version of this during my DIR days. I know that the second half of the dive is done in 10-foot increments, and I know the reason for that is to be consistent with deco diving. So I repeat the question I asked earlier--why is it so important during an OA event to begin training a recreational diver for technical diving?[/quote][/QUOTE]

 

[Hartattack]

To tired to read all of this since it’s pretty redundant but…

some presume a pony is to complicated for a newish diver to operate yet advocate that said same newish diver can handle doubles, same number of tanks and regulators but one tank being smaller.

more air isn’t better but more more air is…


In which proof scenario of doubles being better because more more being better than more would not a rebreather be better better?

A pony is a waste of equipment and non-streamlined when one already has the tools to calculate the gas needed to get to the surface on back gas in an OOG situation.

However, if one finds they want more bottom time, after MG calculations, learn in doubles. The diver is still streamlined, creates less drag and conserves gas while now accomplishing a balanced rig.

Still no need for a pony bottle.

A CCR is not needed for recreational diving why are we bringing this up?

 

[CT-Rich]

Cool gif, Maybe I should ask this question, do you all think a controlled ascent rate of 10 feet per minute would be difficult?

I think the question is not difficulty, it is why? You could make this ascent safely on an NDL dive at 30’ per minute. If you have the gas and nowhere else to be, sure. But if you sharing air and your dive buddy is in a bug-eyed close to panic a spear perforating his abdomen and his air cylinder (curse you Mr Bond…). Why not step it up a little? DAN recommends 30-60’ per minute for recreational divers.
Ascent Rates - Divers Alert Network

 

[boulderjohn]

Cool gif, Maybe I should ask this question, do you all think a controlled ascent rate of 10 feet per minute would be difficult?

That isn't really the question, although in the case of a panicked OOA diver it certainly might be.

The question is why is it necessary for an OOA team to ascend that slowly?

 

[Hartattack]

Not really, but to a certain extent it would help. You are insisting that the OOA team do a 9 minute ascent, and the reason for that has to come down to that sort of thing, doesn't it?

A couple years ago I worked with Dr. Simon Mitchell and published an an article on ascent profiles in decompression diving. That put me in touch with a lot of that research. I wanted to follow up with an article on ascent profiles on NDL dives, but Simon declined to participate--he said there is not enough definitive research, and he did not have an opinion. So I set out on my own, and I believe I read all the most recent research and decided that, like Simon, I could not form an opinion on an NDL ascent strategy. The general approach that has been used for more than 100 years is still the most thoroughly studied and proven.

That is why I contacted GUE and asked for an official explanation, as described above. They confirmed that the only physiological basis for the approach is their belief that the ascent should slow down when nearing the surface. They could cite me no research in support of that belief.

So I really do like to know scientifically why the min deco approach is so critical that it needs to be used during an OOA event.

Outside of DIR circles, more than a century of research has indicated that if a diver within NDLs ascends at a safe rate, that alone is enough to off-gas. A few decades ago, safety stops were added to play it safe. So, using the theories 95% of the diving world uses, a diver ascending from 80 feet should be able to do so safely in less than 3 minutes. Add a safety stop, and you are at 6 minutes. Why should it take 9?

I know all that. Remember that I got the detailed explanation from GUE, and I was myself trained in the UTD version of this during my DIR days. I know that the second half of the dive is done in 10-foot increments, and I know the reason for that is to be consistent with deco diving. So I repeat the question I asked earlier--why is it so important during an OA event to begin training a recreational diver for technical diving?

[/QUOTE][/QUOTE]

That’s great you were working with Simon, and that level goes above my head, so I cannot comment on what I don’t know. With that said, GUE trains students with the end goal in mind, and most of the folks coming to them are interested in advanced technical and cave diving. So I’d say you answered your question, we don’t know, but we have an idea of what works for now. With the ascent rate debate finalized, can we get back to the original topic, pony bottles in rec diving?

 

[CT-Rich]

A pony is a waste of equipment and non-streamlined when one already has the tools to calculate the gas needed to get to the surface on back gas in an OOG situation.

However, if one finds they want more bottom time, after MG calculations, learn in doubles. The diver is still streamlined, creates less drag and conserves gas while now accomplishing a balanced rig.

Still no need for a pony bottle.

A CCR is not needed for recreational diving why are we bringing this up?

I think maybe the issue here is lack of imagination. When things go to the sh*tter your priorities change. Failing to imagine what could go wrong or how multiple things will go wrong together seems to be a hard concept for you. When things go wrong, it is best not to wait around for the other shoe to drop.

You keep bringing up gas planning like it is a get out of jail free card. It isn’t. Murphy doesn’t care about your plan. A little sea turtle swimming by, a current you didn’t notice or some monofilament line can chuck your carefully planned plan in the circular file. Now select two or three of your favorite oops moments and you have a special day.

 

[Hartattack]

I think maybe the issue here is lack of imagination. When things go to the sh*tter your priorities change. Failing to imagine what could go wrong or how multiple things will go wrong together seems to be a hard concept for you. When things go wrong, it is best not to wait around for the other shoe to drop.

You keep bringing up gas planning like it is a get out of jail free card. It isn’t. Murphy doesn’t care about your plan. A little sea turtle swimming by, a current you didn’t notice or some monofilament line can chuck your carefully planned plan in the circular file. Now select two or three of your favorite oops moments and you have a special day.

CT, I come from a 10-year military background. It is better to mitigate risk and that proper planning prevents poor performance than just throwing on a pony bottle and hoping for the best. Moreover, in my calculations/planning, my team and I pad them with conservatism so when the excrement hits the proverbial fan, we have some time to make adjustments. Nevertheless, I lost my imagination for "what ifs" after three deployments to Iraq and the Northern Arabian Gulf during my stint from 01-2011. However, we can agree to disagree until the cows come home. Cheers.

 

[James79]

It is better to mitigate risk and that proper planning prevents poor performance than just throwing on a pony bottle and hoping for the best.

Respectfully, why is it one or the other. People are acting like carrying a pony is mutually exclusive to using proper planning.

James

 

[boulderjohn]

I stayed out of this all for awhile, and by participating as I finally did, people may not realize that I have not actually given any information about what I feel about the great pony bottle controversy.

I have done oodles of recreational dives all around the world--check my profile. I doubt if I have seen a dozen pony bottles being used by others in those experiences. During that time, I have never seen an OOA event. I was in the vicinity of one once, and that was handled quite routinely by the buddy team involved.

I almost never use a pony in recreational diving. I monitor my gas usage and will always have enough gas for both my ascent and to assist another's ascent if needed. If the evil Lord Voldemort makes my gas and my buddy disappear at the same time, I will casually do a CESA. I don't do a lot of solo diving, but I do bring a redundant air source then.

I like to get the most out of my dives that I can, so I make sure I have enough gas to have a full dive experience and still bring myself and another diver to the surface, even with a stop along the way. I will not, however, reserve so much damn gas and valuable dive time that in an incredibly rare OOA event we will have enough air between us to do some leisurely sightseeing on the way up and maybe begin doing some initial tech training along the way.

When I am planning to do a recreational dive near NDLs, I will sometimes bring along an AL 40 with some deco gas. If I slip a little into deco, I will have both redundancy during the ascent and the ability to accelerate that deco. You can call that both a pony and a deco bottle if you like, although I have just learned that doing that is forbidden by the people who establish rules on topics like that, whoever they are. (If deco is planned, I go into full tech mode.)

Those are my choices. I have no objection to others using different choices on their dives. Want to use a pony? Great! Go for it? Don't want to and have good gas management skills? Great? Go for it!