Is there a valid reason for a pony bottle

[MaxBottomtime]

On the other hand, several of the handful of people commenting in this thread have personally witnessed or encountered this. Therefore, while I can't give you a precise incidence - I can comfortably state that it is an actual risk. Which is what we were discussing.

The encounters posted in this thread could have all been eliminated by checking gear before you get in the water or not putting yourself in situations where a redundant gas source is warranted. I'm not saying it's wrong to have a pony. I'm saying that most of the incidents you read about could have been avoided in the first place. Not every OOA is the result of a first stage spontaneously exploding.
I know, I know. Everyone wants to hear others' opinions...unless they differ from your own. I'll go away now.

 

[BRT]

Burst LP hose? No kidding? If the 1st stage fails to control the pressure the air will simply leak through the 2nd stage or octopus. Unless the hose was badly mistreated or was too old, of course.

About 2:30

 

[flyboy08]

The encounters posted in this thread could have all been eliminated by checking gear before you get in the water or not putting yourself in situations where a redundant gas source is warranted. I'm not saying it's wrong to have a pony. I'm saying that most of the incidents you read about could have been avoided in the first place. Not every OOA is the result of a first stage spontaneously exploding.
I know, I know. Everyone wants to hear others' opinions...unless they differ from your own. I'll go away now.

You just couldn’t be more wrong! I’m scratching my head as to why you feel if it’s working topside it’s good to go below?

 

[Rred]

"A burst LP hose is also a reported scenario. Either of those can drain a full AL80 in a minute or so..."
So we've all been told, in many places. Except, I've seen a Youtube video where someone intentionally cut his first stage hose in a pool. Took way longer than a minute, no urgency involved.

It is distressing that DAN would officially call OOA incidents a "trigger" in 41% of SCUBA deaths, because I've heard from one of their speakers directly that yes, something like 41% of all dead divers had no air in their tanks. HOWEVER, that was never shown to be a "trigger" or a direct "cause" any more than "going swimming" caused them to die. OOA is never(?) a CAUSE of a fatality, we are supposedly trained to deal with it in many situations. In open water recreational diving--as opposed to cave penetration and decompression dives, etc.-- emergency ascents are often feasible BUT how many divers would have the presence of mind to follow through and do one? Case in point, maybe 10 years ago, when a newly certified diver off Hawaii drowned in about 35' of water, when all she needed to do was ditch her weight belt or doff her tank to get to the surface. But, she was newly certified and apparently not very well.

People talk about diving being "relaxing" and I've heard DAN speakers talk about the way divers can get "distracted" by their photography or the pretty fishes, etc. What no one seems to be taking official cognition of, is that human beings can and will go into "flow time" when they are deeply involved in something. When you're in flow time, you can think you've been doing something for twenty minutes, but look up at a clock and "Holy *** Batman!" it is four hours later than you thought. Diving is, or should be, conducive to flow time and as such "Remember to check your SPG" is really a load of bunk. Yes, I check my SPG. I also stick to my J valves, because they'll slap me in the face and say "Yo, Dummy! Time to get some air here!" whether I'm looking at them or not.

The industry (PADI, DAN, DEMA, everyone) needs to wake up to some basic psychology and human behavior, and either revert to J Valves (no excuses, they just work) or go to some other simple system, without the bulk of pony bottles (profitable sales and service required, haha) that will consistently slap the diver in the face, and say "Yo! Time to get some air here!".

Beyond that, well, like some of the old NASDS arguments went...some people should simply NOT be certified for diving. Or many other things, including saber dancing.

 

[doctormike]

The encounters posted in this thread could have all been eliminated by checking gear before you get in the water or not putting yourself in situations where a redundant gas source is warranted. I'm not saying it's wrong to have a pony. I'm saying that most of the incidents you read about could have been avoided in the first place. Not every OOA is the result of a first stage spontaneously exploding.
I know, I know. Everyone wants to hear others' opinions...unless they differ from your own. I'll go away now.

You don't need to go away, but if you want to participate in the forum, you might want to read other people's replies.

In my case, I carefully avoided breathing my regs until I was underwater (to avoid icing), and within 15 minutes I had an unrecoverable free flow. I shut down that post and thumbed the dive. Fortunately, I had a redundant gas supply. My gear was in good shape. Not sure what else I could have done to avoid this problem.

And I certainly do want to hear other's opinions, especially when they are different from my own. I don't know everything, and I'm always open to learning.

 

[markmud]

I like a good pony too, it is an equipment solution to a buddy problem.

Has anyone's position changed?

Hi lowviz,

I doubt that anybody has changed their thinking on pony bottle redundancy issues.

I think we would have to start a thread about how people think differently and yes, dive differently.

Max has posted that most of his buddy's dives are in the 35' to 65' depth range. At those depths, a completely redundant system is not as necessary (or necessary at all) compared to one of my dives where I may be between 110 ft. to 120 ft. for almost ten minutes. Redundancy is a much more essential for me than Max's buddy.

Next, we would have to discuss how some people rationalize, project, and through a series of desensitizing adventures, become mentally immune to following standards and safe protocols because "they have dived that way for at least 1,000 cycles and have never had a problem."

To iterate, we have probably not changed many minds, either pro or con.

markm

 

[doctormike]

"A burst LP hose is also a reported scenario. Either of those can drain a full AL80 in a minute or so..."
So we've all been told, in many places. Except, I've seen a Youtube video where someone intentionally cut his first stage hose in a pool. Took way longer than a minute, no urgency involved.

Read the study where they tested that. A cut LP hose drainage rate isn't dependent on depth, but a free flowing second stage is. And late in the dive when you are close to ascend pressure, and don't have a full 80, it will drain a lot faster.

In open water recreational diving--as opposed to cave penetration and decompression dives, etc.-- emergency ascents are often feasible BUT how many divers would have the presence of mind to follow through and do one?

CESA is a terrible option, even if you are capable of doing it. It involves a significant risk of DCS, especially late in the dive, and should never be plan B. It's good to be able to do it when necessary, but you should always have a better option before going to that.

 

[Gareth J]

The encounters posted in this thread could have all been eliminated by checking gear before you get in the water or not putting yourself in situations where a redundant gas source is warranted. I'm not saying it's wrong to have a pony. I'm saying that most of the incidents you read about could have been avoided in the first place. Not every OOA is the result of a first stage spontaneously exploding.
I know, I know. Everyone wants to hear others' opinions...unless they differ from your own. I'll go away now.

In general I agree with your point.

I think earlier in the tread I made the point that, the UK 'recreational diving' norm is different from the USA 'recreational diving' norm. One other point is that Californian diving is different from diving in New York. The UK, I would suggest is probably closer to New York.

As a general rule, UK diving involves.

1. Cold water diving
2. Low visibility
3. Low Light Levels.
4. Higher risk of entrapment/entanglement
5. Deeper
6. Compulsory decompression
7. Strong Tidal Waters
8. High risk of diver separation

(However, visibility can be fantastic, light levels superb. We also have hugely historical wreck sites, like the HMS Colossus. and wonderful marine life, - both macro and wide angle)

This is reflected in a number of ways, equipment, diver training, expectation.

British divers are taught to dive as buddy pairs, not as a group. The DM guide leading 10 or more divers in the UK, is generally unrealistic, it is often difficult to maintain visual contact with a single buddy.

There are thousand of dives done, with a standard single cylinder, BC/Wing, and Regulator + Octopus. These are carried out without incident. Many divers only ever use an Octopus during training.
Part of the issues with boards like this is they are international, the discussion are carried out between divers of significantly different levels of experience, both number of dives and enviroment. This can cause diametrically opposed views, confusion, etc. But if nothing else, its an education to be involved in them, it's nice to have the opportunity to learn something new.

 

[markmud]

Read the study where they tested that. A cut LP hose drainage rate isn't dependent on depth, but a free flowing second stage is. And late in the dive when you are close to ascend pressure, and don't have a full 80, it will drain a lot faster.



CESA is a terrible option, even if you are capable of doing it. It involves a significant risk of DCS, especially late in the dive, and should never be plan B. It's good to be able to do it when necessary, but you should always have a better option before going to that.

Hi Dr. Mike,

And...if you do it wrong you may suffer AGE?

DCS, including AGE, or lucky. I'll take the pony with me instead.

markm

 

[Gareth J]

I quoted the BSAC incident report earlier in the thread. This is very UK based, but if you are interested follow the link!

Note - You should see the links for each year back to 2012.