Is there a valid reason for a pony bottle

[tarponchik]

I don't know the stats on first stage failures. But on a personal level;

• I have had one good friend have a first stage fail catastrophically (The brass housing split).
• My first Open Water UK trip, in the middle of winter. Three divers (two with recently serviced regulators), had three first stage failures between them. Diver A iced a regulator, when't to his pony, Diver B, had a similar problem, switched to his pony. Diver A then had a second failure, diver C donated gas to diver A, from his pony. (pre twinsets in my group.)
• I had a student Ice a first stage, very close to the start of the dive. He when't on to my long hose.
• I had one regulator first stage that was prone to failure after servicing. Ten dives without problems after servicing and it was good.
• I had a seat delaminate in the summer on my CCR.

Those are the ones that come to mind with no effort.

Your highest risk is after having regulators serviced. Failures are disproportionally high after servicing. Often, because there is little time given to allow the regulator to 'bed in' . My favourite service centre used to leave all regulators 24hours with high pressure on them. Then test dive them, then double check the I/P and check there was no I/P creep. Most places just service them, put regulators back together, set them up to the manual, and give them back. (Not surprising, you don't really pay a lot for a regulator service.)


[1] Iced = free flow due to ice build up.

So you have another risk factor, icing. I do not have this problem sice I only dive tropical or subtropical waters. Re reg servicing, this is what the manufacturers insist on.

 

[tarponchik]

Though I dive with an octopus, octopuses failed twice when I was diving, forcing me to cut short the dives. The more complex the system is, the more likely it is to fail

 

[Gareth J]

Ignoring that a lot of failures seem to happen shortly after servicing, would you agree that annually servicing your regs is a reasonable alternative to carrying octopuses?

Remember, your Octopus is not for you .... but you're buddy.
His Octopus is for you ..... assuming it isn't full of sand and gravel and has been serviced this millennium.

Personally, if you joined us without an Octopus, you wouldn't be diving with the majority of us. If you don't think its worth your while to have the minimum level of equipment to see your buddy back to the surface. You are probably not going to find many to trust you in the water.

I dive mostly CCR. For shallow (20m) diving, I have enough bailout gas to get me back to the surface using the BOV. Because most of those I dive with are on OC, I always carry a stage, general an Ali80. It's mainly there for my buddies, this is despite the fact that other than students (who I'm not supposed to be diving with on CCR), they will in all probability be carrying a pony, or on a twinset.

 

[saxman242]

Remember, your Octopus is not for you .... but you're buddy.
His Octopus is for you ..... assuming it isn't full of sand and gravel and has been serviced this millennium.

Personally, if you joined us without an Octopus, you wouldn't be diving with the majority of us. If you don't think its worth your while to have the minimum level of equipment to see your buddy back to the surface. You are probably not going to find many to trust you in the water.

I dive mostly CCR. For shallow (20m) diving, I have enough bailout gas to get me back to the surface using the BOV. Because most of those I dive with are on OC, I always carry a stage, general an Ali80. It's mainly there for my buddies, this is despite the fact that other than students (who I'm not supposed to be diving with on CCR), they will in all probability be carrying a pony, or on a twinset.

But why would my buddy need my octopus if he has properly planned his dive and keeps his gear serviced? Are you suggesting that despite proper planning and maintenance, sometimes things can still go wrong in a hurry?

 

[BRT]

If you don't carry an octopus, I see no other alternative than buddy breathing off your primary if your buddy is OOG. And that is currently considered high-risk and has been taken out of the OW curriculum. If you don't carry an octopus, what are you going to do if your buddy is OOG?

Also, I don't understand how annually servicing your regs isn't compatible with carrying an octopus.

It might be, if annually servicing your regs made them more, rather than less, reliable.

 

[doctormike]

Going back to the OP, the question for me is the question of the probability of the 1st stage catastrophic failure. I do not know the stats for this, and I do not know if anyone does. I have never witnessed this happening to somebody else, though I read sometime ago some anecdotal stories about Leo Di Caprio saving Bradley Cooper, or maybe this was some other celeb.

Why do you think that the relevant failure is limited to a first stage failure, one of the less common ones? What is the statistical significance of you personally never having witnessed something while diving?

Just in this thread alone, many people (including me) have noted the experience of an unstoppable free flow. A burst LP hose is also a reported scenario. Either of those can drain a full AL80 in a minute or so...

 

[Gareth J]

But why would my buddy need my octopus if he has properly planned his dive and keeps his gear serviced? Are you suggesting that despite proper planning and maintenance, sometimes things can still go wrong in a hurry?

Things go wrong. That is a fact of life. It might not be your direct fault.

Diving is a sport with small risks. The issue is the consequence. Hence, during training, we spend time teaching you how to cope with these. Be they a mask flood, or a loss of breathing gas.

The historical philosophy of recreational diving, is that you have a buddy, for safety and assistance in the event of a problem. Not carrying appropriate safety equipment for your buddy, indicates you don't take your responsibility very seriously.

There are those on the boards that dive solo, (I have/do on occasionally). I am suitably equipped, and dive defensively when I do dive solo. Most of my diving is with a buddy(s), I take my responsibility to them seriously. Most of us are technical trained and are also instructors, so dive as if we where solo, i.e. equipment redundancy.
Deep dives mean rule of thirds and 50's (thirds for back gas, 50% for decompression gas). CCR it means sufficient bailout gas for myself and my OC buddy.


ADDENDUM
Looking at the BSAC 2018 Incident report. There where 42 ascent related incidents in 2017-2018 incident year. Of these 27% where incidents where divers ran out of gas or lost their gas during the dive 9% where directly related to free flows. Thats 12 Out of gas, and 4 free flows.
These are those incidents actually reported, which is statistically quite low.

 

[drbill]

Can anyone give a valid reason for a pony bottle? SO many things need to be wrong before it makes any sense to me.

If you have been extremely lucky or just not been diving much, you may not have experienced a situation where a pony bottle might be a life saver. I've dived for 56+ years and although my pony was only used a few times, it probably saved my life. I do most of my diving solo, but if you dive with a buddy who is at a distance, it could still be a critical life saver.

 

[Kharon]

Hi Kharon,

As usual, I like your posts and logical thinking.

I did not express myself well in the sentence you quoted and commented on.

We have divers on this thread who have thousands of dives and have never suffered a major or catastrophic failure where a pony bottle would have been a good piece of equipment to have. I have relatively few dives compared to them. I maintain my gear well and have trained techs inspect and overhaul the most critical pieces of gear. I have had issues u/w while others have never had a problem with a piece of equipment or a dive buddy.

My point is: some of us have both good luck and bad luck. My 1st stage that was catastrophically failing was inspected by two different dive shops just before it failed. I performed my due diligence.

Usually, I create my own good luck--it does not just happen to me. Redundancy rules on the ocean.

Sheet happens to some more than others. Life is not fair.

That was my point.

markm

Hey, sorry it it came across like anything but the comic relief intended. It was supposed to be funny and get a chuckle.

I thought you were spot on. I have had numerous experiences when my first thought was "Why now?". Some in diving, most not. When the timeing is good the problem seems very minor. When the timeing is bad it seems to grow in proportion.

I've gotten tangled in my dive flag cord at 90 feet (my bad) and several times at 5 feet. At 90 feet it was a problem. At 5 feet - not so much - simply an irritation.

 

[TMHeimer]

I've gotten tangled in the dive flag cord very shallow as well, despite my "expertise" on how to hold it to avoid that. I am fortunate that at almost all shore sites here it's not necessary as there are virtually no boats. Not so much in Connecticut....