Is there a valid reason for a pony bottle

[Edward3c]

That was one reason PADI gave to Undercurrent it seems, despite being completely untrue.

Besides, you can’t fix drowning. Most other stuff you can.

Here’s a good article on it. It mentions the one, single death reported from a diver who got a lung infection from inhaling from his bcd. It was written by our own DocVikingo.

Emergency Breathing from Your BCD: Undercurrent 06/2011

The risk was that individuals would get a fungal infection during training, not from using the technique to save their life. The article makes no reference to this aspect.

 

[happy-diver]

Yep there's 840 litres of 50% in mine

 

[Colliam7]

So in conclusion diving with a pony is a result of - a deficiency in skill, lack of teamwork, the inability to plan a dive and monitor your gas, or my personal favourite the “I don’t rely on anyone” because I think I’m Rambo.

I am not sure those are the only, or even the logical, conclusions to be drawn - unless that is just what you want to believe.

Yes, there is certainly no lack of poor planning among some divers. In fact, for too many divers it seems that the primary plan is to 'be back on the boat with 500 psi', and that doesn't really constitute 'dive planning'.

Yes, some divers go in the water planning to use their pony bottle to extend their bottom time. When that is done without any actual calculated plan, that is a poor practice.

And, yes, there are divers who do not seem to have any situational awareness, and manage to find themselves at 110 ft, with no buddy in sight, and their first glance at the SPG since they splashed (a glance taken because the breath they they just took seemed a little hard) reveals that they are out of gas.

But, that doesn't mean that all divers are like that. In fact, the divers that I know who wear a pony are generally the opposite - they are often meticulous planners, good buddies and generally conservative divers.

Now, I am certainly not Rambo, far from it (although I thought the torn strip of cloth tied around his head as a headband did look cool). And, in my personal diving (i.e. non-teaching), I only dive with individuals known to me, who I trust as a buddy (and who trust me as a buddy). BUT, I personally choose to be as self-reliant as possible - I don't want my buddies to have to worry about me, any more than I want to spend my dive 'worrying' about them. I personally believe, and teach, that every diver should work toward being as self-reliant as possible. Maybe, I go overboard. I carry two cutting devices, even though I could carry one (or none, I guess) and trust my buddy (or buddies) to help cut me out of fish line or netting or whatever.

And, if I am diving a single cylinder rig deeper than I feel personally comfortable with doing a CESA (for me, that is 60ft), I usually carry a pony, even though I am diving a solid plan, using well-maintained equipment, with divers I know and trust. I have NEVER had to use a pony in an emergency. But, I still carry it, and train with it, just in case. In the (very unlikely) event of a primary gas supply system failure, I have redundancy, in addition to my buddy. For me - probably for others who have responded here - that is a valid reason to carry a pony.

 

[Storker]

Maybe, I go overboard. I carry two cutting devices, even though I could carry one (or none, I guess) and trust my buddy (or buddies) to help cut me out of fish line or netting or whatever.

If that's going overboard, I'm probably marooned I carry three cutting devices (large knife on my calf, small knife on my waistband and a ceramic trilobite-type line cutter.

But I have an excuse. Since I'm usually carrying a camera rig, I don't want to have a sling to manage as well. So if I stumble on a wolffish, anglerfish or flounder, I use the big knife to stab it, and the small knife to finish it off. And since a half-decently sharp knife isn't the best tool for cutting monofilament line, I'm carrying a line cutter on my shoulder strap. Like the backup light I'm carrying on the other shoulder strap, it just stays on my harness, and I don't even notice it until I want to use it.

 

[2airishuman]

I'm amazed at the volume of posts that don't really answer the OP's question.

Yes, there are situations where there are good and valid reasons to dive with a pony bottle. There are three parts to the decision:

1. Whether a redundant air supply is necessary for a safedive
2. Whether a pony bottle is the best redundant air supply under the circumstances
3. What sizes pony bottle would be appropriate

There are many dives where some sort of redundant air supply is widely considered necessary to complete the dive safely. While some of these dives are outside the scope of the Basic forum, they are nonetheless worth brief mentions as part of a complete answer. The dives where redundant air is widely considered necessary include:

1. Cave dives
2. Wreck penetration dives
3. Decompression dives
4. Solo dives to depths beyond around 30-60 feet
5. Coldwater dives where regulator freezeup is a major concern
6. Buddy dives to depths beyond around 30-60 feet where visibility, the buddy's inexperience, other factors that could lead to buddy separation are present.
7. Dives with other risk factors, such as entanglement, or lack of reliable surface support,

Now, there are a variety of redundant air supply alternatives that have various pros and cons. The choices as I see them are:

1. Manifolded backmount doubles.
2. Independent backmount doubles.
3. Sidemount.
4. Use of an H-valve.
5. Pony bottle, either alone or in combination with any of the above systems.
6. Larger single cylinder.

I have used all of these except sidemount. They all have pros and cons. I find that I use manifolded doubles on most dives where I want redundant air, but that isn't a suitable strategy in all cases. Here's a rundown of the pros and cons.

Manifolded doubles (backmount). With proper training, these are widely considered the gold standard for redundancy, because they provide access to the full gas supply in the event of most equipment failures. They do require skill to use, and are heavy, and require equipment that is difficult to find on a rental basis, and are not permitted on many boats. Progressive equalization can be used in situations where the main concern is SPG monitoring or failure.

Independent backmount doubles. An alternative to manifolded doubles that provides a similar level of redundancy. No manifold is used, and a second SPG is required to monitor the second cylinder. The main advantage over manifolded doubles is that there is no need to source twinsets; ordinary AL80s can be used. Heavy, requires a suitable BC and a special regulator setup, and skills.

Sidemount. Similar to independent backmount doubles but lighter to handle since there is never a need to lift both cylinders at once while topside. I haven't used sidemount and will leave a more thorough treatment to people who have.

H-valve (or y-valve) For those not familiar, this is a setup where there are two valves and two 1st stages attached to a single cylinder. Usually a large cylinder, 117-149 cf, is used. Useful for dives where the main redundancy concern is equipment failure. Requires skill to use. The valves are harder to reach than for manifolded doubles. Lighter than manifolded doubles of the same capacity, compatible with any BC.

Pony bottle. What we're here to discuss, with various size and rigging options. When I use one, I sling it, because I believe that's safer and more flexible than backmounting it.

Larger single cylinder. Typically not considered "redundant air," but where the main concern is simply exhaustion of the primary air supply due to an SPG failure, or failure to monitor the SPG, or whatever (rather than some sort of equipment failure) it is an alternative to consider.

Now, considering all that, sure, there are situations where a pony bottle is the best answer. I do find that I prefer manifolded doubles, but it isn't always feasible to use them. A pony bottle is relatively portable and, unless deployed, can be used for multiple dives between fills. So you can use an AL80 or whatever that you've rented locally or that is provided by the boat, and augment it with a pony for redundancy. That's the most common use case.

Some divers use a pony bottle in addition to some other form of redundancy (such as manifolded doubles) for safety in the event of entrapment or entanglement. Doing so allows the alternative of abandoning the entire scuba kit and completing the dive with the pony alone. Careful attention to weight placement is vital, and overall, this is an advanced technique.

We've had endless discussions on the best size pony bottle to use. There is no single correct answer as it depends on the circumstances of the dive and the goals of carrying a pony bottle. I most often use an AL19, but not always.

I'm also going to quote part of Stoo's post which is insightful and worth reading in full.

In these parts, a catastrophic reg freeze-up is a distinct possibility for about 1/2 of the dive season, and a reasonable possibility for the rest of it.

If you've never been in water colder than 40 degrees, you probably don't realize what it's like.

 

[Wookie]

If that's going overboard, I'm probably marooned I carry three cutting devices (large knife on my calf, small knife on my waistband and a ceramic trilobite-type line cutter.

But I have an excuse. Since I'm usually carrying a camera rig, I don't want to have a sling to manage as well. So if I stumble on a wolffish, anglerfish or flounder, I use the big knife to stab it, and the small knife to finish it off. And since a half-decently sharp knife isn't the best tool for cutting monofilament line, I'm carrying a line cutter on my shoulder strap. Like the backup light I'm carrying on the other shoulder strap, it just stays on my harness, and I don't even notice it until I want to use it.

Are wolffish good eating?

 

[Storker]

Are wolffish good eating?

You've got PM (so we don't derail the thread even further).

 

[doctormike]

Like the backup light I'm carrying on the other shoulder strap, it just stays on my harness, and I don't even notice it until I want to use it.

Yup. Just like my pony bottle.

 

[caruso]

I have never run out of air, never had a free flow, never had a first stage failure and never had to make a CESA. .

You may never have had a free flow or first stage failure and you may have never screwed up and found yourself low or out of gas but it has happened to many other divers. Enough times that it's an issue that cannot simply be ignored because it hasn't happened to YOU.

Your rather egocentric selfish way of thinking is a danger to other divers when you push your beliefs onto them in the form of rules they must follow when they dive off of your boat.

That much being said- I was mistaken earlier when I first responded to your post on this thread. I incorrectly assumed that you operated a commercial dive boat and you impose your questionable rules on paying customers that might not have been told beforehand and are stuck either diving without their preferred safety gear or skipping the dive (if they can't reschedule with another dive op last minute). You have since clarified that you only take your friends out- in which case it doesn't matter how absurd your rules are you can do as you please it's their choice whether they want to hang out with and dive with you.

 

[doctormike]

Larger single cylinder. Typically not considered "redundant air," but where the main concern is simply exhaustion of the primary air supply due to an SPG failure, or failure to monitor the SPG, or whatever (rather than some sort of equipment failure) it is an alternative to consider.

Excellent writeup, one minor quibble. Larger cylinder isn't redundancy in any way, and I wouldn't consider it a way of addressing those problems you listed. If you aren't monitoring your SPG, a larger tank isn't a solution. The reason to use a larger single tank is if your SAC rate is so low that you are limiting your buddy's dive, or if your dives are gas limited when they could be NDL limited.