Pony bottles/spare air

[Frosty]

This causes a major shift in role.

Without a primary AAS, the Pony system ceases to be redundant alternate air and becomes the initial recourse to an air-supply problem. In solo diving, that has debateable pros and cons. However, for buddy/team diving, it reduces options substantially, with little benefit.

Could you justify that statement please especially the second part?
(No not having a go Im genuinely trying to work through this in my head)
Im thinking-Ok I have a problem with my primary then I switch to my pony and thumb the dive.Head up on the pony with my buddy able to look over my primary rig.
My buddy either has his own pony so if he has primary failure he does the same. If not then I use the pony as the octo and Im also able to "donate" the whole pony rig to him if we are in an enviroment where being linked together is an issue.
If the pony runs dry the share air senario is up towards the surface you would hope

Whats wrong with my thinking here?

 

[DevonDiver]

If you have an AAS (from your primary tank), that is your first alternative. You retain the pony as a second alternative. That gives you two alternative resolutions to the problem of donating an air-source.

If you have no AAS (from your primary tank), then your pony is your first and only alternative. That gives you one resolution to the problem of donating an air-source.

2 potential resolutions is more preferable than 1.

If anything should arise that makes a solitary resolution unavailable, you are left with none. That situation should be avoided..

 

[rx7diver]

If you have an AAS (from your primary tank), that is your first alternative. You retain the pony as a second alternative. That gives you two alternative resolutions to the problem of donating an air-source.

If you have no AAS (from your primary tank), then your pony is your first and only alternative. That gives you one resolution to the problem of donating an air-source.

2 potential resolutions is more preferable than 1.

If anything should arise that makes a solitary resolution unavailable, you are left with none. That situation should be avoided..

DD,

We need to keep in mind the purpose of carrying a pony/bailout system--viz., to have a completely independent air supply (which serves as redundancy for the primary air supply). Carrying a bailout system makes superfluous an octopus 2nd stage on the primary cylinder.

Now, someone might decide to retain the octopus 2nd stage on his/her primary cylinder for whatever reason, but this means he has increased the complexity of his kit for either arguable or dubious advantage. Similarly, he might decide to add an octopus 2nd stage to his pony/bailout cylinder. More complexity, with either arguable or dubious advantage.

Personally, for my recreational diving, I see no compelling reason to retain the octopus 2nd stage on my primary cylinder when I'm carrying a bailout bottle. (Nor do I see a compelling reason to add an octopus 2nd stage to my bailout bottle.) However, I do in fact retain my octopus 2nd stage (actually, my AIR II) on my primary cylinder simply because doing this is easier than changing it out for a power inflator, not because of any perceived safety benefit.

Safe Diving,

rx7diver

 

[DevonDiver]

We need to keep in mind the purpose of carrying a pony/bailout system--viz., to have a completely independent air supply (which serves as redundancy for the primary air supply). Carrying a bailout system makes superfluous an octopus 2nd stage on the primary cylinder.r

There's an err in logic. Carrying a redundant system is not a replacement.

I guess it depends on whether you consider the pony to be redundancy for your primary and/or your AAS.

For a solo diver... who doesn't have to share air (theoretically)... a pony is redundant gas.

For a buddy/team diver... who does have to share air... a pony shouldn't be a replacement air-source. It should still be a redundant source. Otherwise, it just becomes a very bulky and unnecessary octopus.

If the pony is shared/donated... the primary diver loses their redundancy. No further issues can be dealt with. If an AAS is shared/donated, then the pony is reserved for further contingencies. A 'fail-safe' as it were. I believe that many divers view the pony as a 'fail-safe',... an additional measure, not a replacement measure.

 

[DaleC]

I would have to disagree.

Most buddy teams really only have recourse to a single alternate air source in case of their own failure; their buddies octo. The pony equipped, single second stage on back gas team diver is in the same boat, only their second stages are divided between two cylinders.

The accepted protocol for a single failure is to resolve the immediate issue and abort the dive in a straightforward manner. This is an important safety concept that can be complacently overlooked when a pony equipped diver has two second stages on their back gas. Most notably this occurs when a diver is low on air. The pony equipped diver may donate that gas to prolong the dive thinking they have lot's. It shouldn't happen but it does. Now, if the pony equipped diver has a failure they have no recourse but to wrestle the pony reg back from the LOA diver. Bad mojo that probably wouldn't happen if the pony diver removed their octo. I've seen more than one diver do this, more than once.

I dive a pony, buddied or not, because I want to have a reserve of gas that is separate from my back gas in case of failure. Not because I want the chance to deal with two failures.

As soon as one is diving in a way that direct ascent is not possible one is no longer recreational diving and "technically" no longer using a pony. After that it would be considered a stage, deco or bailout bottle and different rules for their use would apply. A pony is really a recreational tool and in rec diving I've never heard anyone advocate planning for more than one failure.

 

[je76]

I agree with Dale here. I religiously dive a pony bottle even when diving my doubles simply because, "I want a reserve of case that is separate from my back gas...".

My favorite saying here is 2 is 1 and 1 is none. As Dale pointed out even with a pony equipped once one of my second stages fail, dive is over I abort on the working reg and hold the pony as my redundancy/reserve gas.

If I am staging a tank for an extended dive I carry a pony (typically a 30 cf bottle) filled with my back gas to act as a redundancy in the event I suffer a failure. This pony has nothing to do with my staged bottle and in and of itself is not the same thing.

If I am diving as part of a team I carry my pony so as to be self reliant in the event of separation from the team. This pony redundancy acts in place of a team member should I have a gas emergency during separation. If diving solo the pony acts a redundancy should I suffer a failure in my primary system. This is true even with my doubles...again 2 is 1 and 1 is none

If a team member has an emergency the pony bottle can be removed and clipped to my teammate (after the situation is stabilized) allowing us some distance (small but comfortable) while aborting the dive together.

I would never in any way want my pony bottle linked to the system that is attached to my back because the idea is a separate and redundant system.

 

[shoredivr]

I agree with Dale here. I religiously dive a pony bottle even when diving my doubles simply because, "I want a reserve of case that is separate from my back gas...".

Try sidemount

 

[DaleC]

recreational sidemount was invented by those guys who secretly wanted redundancy but refused to stoop so low as to carry a pony. Now they can have it but still look uber technical

 

[DevonDiver]

I would have to disagree...Most buddy teams really only have recourse to a single alternate air source in case of their own failure; their buddies octo.

I'm not sure we do disagree. My points were only aimed at the suggestion that a pony made an AAS/Octo superfluous for buddy/team divers.

I dive a pony, buddied or not, because I want to have a reserve of gas that is separate from my back gas in case of failure. Not because I want the chance to deal with two failures.

I think most of us do so for the same reason. The critical aspect is that we preserve an AAS/Octo for air-sharing and the Pony for gas redundancy

If buddy/team divers lose the AAS/Octo, then the pony is 're-tasked' for air-sharing. It ceases to be redundancy.

I probably didn't make it clear... but I think we do agree on these points, given the context they were made in.

I agree with Dale here. I religiously dive a pony bottle even when diving my doubles simply because, "I want a reserve of case that is separate from my back gas...". My favorite saying here is 2 is 1 and 1 is none.

You're using manifolded doubles without an isolator?

recreational sidemount was invented by those guys who secretly wanted redundancy but refused to stoop so low as to carry a pony. Now they can have it but still look uber technical

I find it much more comfortable than a high-capacity single and a pony. Plus, I can do a two dive trip with two cylinders, which is nice. I am predominantly diving wrecks though.

 

[Kharon]

Without a primary AAS, the Pony system ceases to be redundant alternate air and becomes the initial recourse to an air-supply problem.

The pony is a redundant independant air source. I see nothing wrong with that. Moreover, I'll go with SDI's recommendation rather than one from someone who appears to disagree for the sake of disagreement.
Whoops, I slipped and replied before I caught myself. Sorry.