Is there a valid reason for a pony bottle

[Stoo]

Figuring that you can always make it to the surface even if you have a catastrophic gas failure without a backup gas supply implies a CESA or breathing from a leaking tank as you rapidly head for the surface. That is NOT a safe, slow ascent with a safety stop.

Whenever I hear someone claim they can make a CESA from whatever depth their diving to, I call BS. 30' sure. 60' perhaps. 100' I give it a 50% likelihood. 150' I would say that very few can do that successfully. And there's a high probability of taking a hit, but better that than dead.

 

[caruso]

there's a high probability of taking a hit, but better that than dead.

Not necessarily.

 

[doctormike]

Whenever I hear someone claim they can make a CESA from whatever depth their diving to, I call BS. 30' sure. 60' perhaps. 100' I give it a 50% likelihood. 150' I would say that very few can do that successfully. And there's a high probability of taking a hit, but better that than dead.

Exactly. And even if they can, it's NEVER going to be as safe as a normal, slow ascent with a safety stop from a decompression stress point of view. CESA is the second worst possible option for an OOG diver. Seriously, why risk it?

I know what you are talking about - I had an unstoppable free flow of one of my regs on an iceberg dive in Newfoundland. Shut down the post, but that was a scary moment. Glad I had redundancy!

 

[HalcyonDaze]

These threads are always good for an explosion of posts.

Personally speaking, if I was doing all my dives with a buddy I trusted to stick close and at recreational depths with no real complications (potential freezing, overhead, etc.), I would have no problem leaving the pony behind. I do leave it behind on shallow dives. I also would not recommend a new diver run out and get one (unless conditions require, see above post), because at that stage of the game you should be conservative, relying on the buddy system, and not piling on gear. To paraphrase one of my literary idols, you should learn everything by the book and rack up some experience before the real sea monsters tell you when it's appropriate to dive separated from your buddy and what kind of bailout to pack.

Me? I started doing a lot of photography and hunting dives on boats where there's little emphasis on buddy pairing and would find myself possibly at 120-140 fsw snapping pictures or hunting lionfish with nobody else in reach or perhaps even in sight. Granted, if I was intent on splitting off from the group for more than a 5-10 minute strafing run at max depth I would be packing a full 120cf tank and be checking my gas frequently. Still, the thought occurred to me that there was a non-zero potential for an equipment failure. I have my gear serviced annually and while it hasn't crapped the bed at depth, I've had a first stage o-ring blow on the boat (after I had already tested it dockside). So last year I talked to a few people, ran the numbers, and decided to start carrying a 19cf pony on those dives. It's not much of a hindrance for the added safety factor, so it made sense.

 

[JXT71]

We know before we get in the water that our gear works and will get us back safely. We don't cross our fingers and rely on extra gear. I also have a waiver for my friends to sign stating that they are aware of the inherent risks of diving and they understand the importance of well maintained gear.

If their gear works and will get them back safely, and they have enough experience to maintain their gear, why the waiver? Aren't you confident in their abilities?

Not confident enough to stake your liability on it - but what reasonable person would? It's enough to assume that there is always a chance for something to go south quickly, no matter how much you prepare for it, and it's nice to have something covering your ass. Which is the same mentality people have to use a pony.

Your boat, your rules... but it's an odd solution. Are spare o-rings and batteries banned, too?

 

[MaxBottomtime]

I put the waiver on the boat because of my friend. We have room for three divers on the boat, Merry, me and one friend. That one friend is the OOA guy and is with us 95% of the time.
To answer some of the multitude posts of "what if" situations, I dived without an octo for nearly a decade, as most of my diving was solo. I added one when I met and began diving with Merry in 2006.
I would not be at 80 feet with 0 ndl and 1,000psi. The dives we make are in the 35-70 feet range. I would not be at 120-140 photographing with a single tank. For most of my dives, the cubic feet of my tank is never less than the depth I will take it. When I make a deep dive I have doubles and at least one deco bottle with me. I've practiced valve drills on hundreds of dives.
I don't dive as often as I'd like, but in close to 2400 dives 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. I guess either I live the "Golden Child" life as one poster said or I don't push my luck. I can look at my spg at any point in a dive and be close to what I thought I should have. I look often. I don't like surprises.

 

[doctormike]

I would not be at 80 feet with 0 ndl and 1,000psi. The dives we make are in the 35-70 feet range. ...

in close to 2400 dives 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. I guess either I live the "Golden Child" life as one poster said or I don't push my luck. I can look at my spg at any point in a dive and be close to what I thought I should have. I look often. I don't like surprises.

This is one of the most frustrating things about ScubaBoard.

You have made a general recommendation that a pony bottle is not necessary. Yet you then qualify your position by saying that you are diving in very specific conditions which is why you don't need one. You are extrapolating from your personal experience that a redundant gas supply is not necessary because you have never needed one.

You are a very experienced diver with lots of dives, but are you assuming that if something like an unstoppable free flow hasn't happened to you - in your very specific diving history - that it just doesn't happen, and therefore redundant gear to address that risk isn't needed by anyone? I mean, it happened to me, and similar things have happened to the few people in this thread, right?

It's fine to say that for the diving you do it's not necessary, but I wouldn't want new divers reading this thread to think that is true in general. You have a lot of experience, people will look to you as an authority. I just wouldn't be so sure that there are no circumstances where a redundant gas supply isn't appropriate.

 

[saxman242]

I put the waiver on the boat because of my friend. We have room for three divers on the boat, Merry, me and one friend. That one friend is the OOA guy and is with us 95% of the time.
To answer some of the multitude posts of "what if" situations, I dived without an octo for nearly a decade, as most of my diving was solo. I added one when I met and began diving with Merry in 2006.
I would not be at 80 feet with 0 ndl and 1,000psi. The dives we make are in the 35-70 feet range. I would not be at 120-140 photographing with a single tank. For most of my dives, the cubic feet of my tank is never less than the depth I will take it. When I make a deep dive I have doubles and at least one deco bottle with me. I've practiced valve drills on hundreds of dives.
I don't dive as often as I'd like, but in close to 2400 dives 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. I guess either I live the "Golden Child" life as one poster said or I don't push my luck. I can look at my spg at any point in a dive and be close to what I thought I should have. I look often. I don't like surprises.

Why did you add an octopus to your set up?

 

[BlueTrin]

In the US is it easy to rent a pony ?

I do not own cylinders (mostly because I live in a flat in London) but I do not think I could easily rent a pony in some sites.

 

[Coztick]

In the US is it easy to rent a pony ?

I do not own cylinders (mostly because I live in a flat in London) but I do not think I could easily rent a pony in some sites.

I would guess most of us users are owners.
A 2 or 3 liter tank will fit in a carry on bag for travel.