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

[wetb4igetinthewater]

I just don’t believe a regulator first stage can fail instantly, not my scubapro,s at least, so the only other reason to end up with no gas is to unwittingly use it. I’m definitely not going to do that.

My Own Out of GAS Experience

So the other week I experienced my first very own out of gas situation and learnt something new. Downstream valves can fail shut!!! I was always told and understood they could only ever fail open c…

grahamsavill.wordpress.com

When recreational diving I have a dive buddy. Most of my dive buddies also take photos and we let one take photos as the other waits nearby. Yes I have had o rings go and a free flow reg that ended a dive. Nothing that prevented me from getting to the surface on my own. Never had a hose burst since I started diving in 1986. Things do happen. Should every recreational diver now plan each dive on a catastrophic air loss situation?

my buddies and I shoot at the same time and check on the other in between shots.

And for your question yes. Just because it hasn't happened to you, doesn't mean one shouldn't plan for it. I've never been in a serious car accident, but I prepare for it every time I'm in a car.

 

[scubaozy]

I think it is a fallacy to assume out of gas or lost buddy scenarios are fully mitigated with a redundant alternate air source. There are millions of ways you can, and will, get caught off guard. This is the reason the incident reports I shared do not favor the pony usage. When you mitigate the risk to your satisfaction with the means you choose, in reality you do not mitigate it to 100%, you just accept the rest risk of the things that you cannot control.

This incident doesn't really lend itself to any conclusions regarding pony cylinders.

meh

 

[jtsfour]

My Own Out of GAS Experience

So the other week I experienced my first very own out of gas situation and learnt something new. Downstream valves can fail shut!!! I was always told and understood they could only ever fail open c…

grahamsavill.wordpress.com

my buddies and I shoot at the same time and check on the other in between shots.

And for your question yes. Just because it hasn't happened to you, doesn't mean one shouldn't plan for it. I've never been in a serious car accident, but I prepare for it every time I'm in a car.

How the hell did a downstream valve fail closed?

 

[Celt]

Me!. I had a chamber dive after being dragged to the surface by an out of control diver. I was close to my NDL when it happened. Maybe I need a BFK.

Definitely those line cutters are rubbish, and I suppose you could have clubbed him with the pony bottle. But we’re not talking about uncontrolled assents

 

[grf88]

You should have used your knife

Shears and a line cutter might not be enough sometimes.

 

[undrwater]

I think it is a fallacy to assume out of gas or lost buddy scenarios are fully mitigated with a redundant alternate air source. There are millions of ways you can, and will, get caught off guard. This is the reason the incident reports I shared do not favor the pony usage. When you mitigate the risk to your satisfaction with the means you choose, in reality you do not mitigate it to 100%, you just accept the rest risk of the things that you cannot control.

meh

It's why we have these discussions. There are no solutions that fully mitigate the risks.

 

[wetb4igetinthewater]

How the hell did a downstream valve fail closed?

I don't know but I that is the second time I've heard of that happening. Now first stages are designed the fail open. That doesn't guarantee it however.

 

[Blackcrusader]

I don't know but I that is the second time I've heard of that happening. Now first stages are designed the fail open. That doesn't guarantee it however.

It was also not an "instant" failure he had sufficient time to realize he had an issue and use his buddy. Just shows that having a good dive partner is a good thing. Life is full of risks.

 

[wetb4igetinthewater]

It was also not an "instant" failure he had sufficient time to realize he had an issue and use his buddy. Just shows that having a good dive partner is a good thing. Life is full of risks.

Sure, life is full of risks. Hence the use of a pony is perfectly acceptable for solo divers or people who are not close to their buddies (the majority).

Mind you, I don't dive single tank accept except for really shallow dives. However, I do respect the reality that others do dive deeper and account for buddy separation.

 

[jtsfour]

I don't know but I that is the second time I've heard of that happening. Now first stages are designed the fail open. That doesn't guarantee it however.

My question was particularly because a downstream valve is much less likely to fail closed.

In a downstream valve the pressure in the tank tries to force the valve open. In an upstream valve the pressure tries to force the valve closed.

I'm not very knowledgeable in that subject, and I can't even imagine how that could happen.