Pony Bottle & octopus

[jo8243]

Opinions requested: Is it necessary to carry a traditional octopus 2nd stage off of your main tank if you also carry a 19 cu ft. pony bottle on every dive (pony has a pressure gauge)? Pony is mounted to the main tank on divers' back and is carried with the air always on.

This questiona applies to recreational diving only. No tech/wreck penetration/cave/cavern, etc.

 

[mike_s]

Opinions requested: Is it necessary to carry a traditional octopus 2nd stage off of your main tank if you also carry a 19 cu ft. pony bottle on every dive (pony has a pressure gauge)? Pony is mounted to the main tank on divers' back and is carried with the air always on.

This questiona applies to recreational diving only. No tech/wreck penetration/cave/cavern, etc.

Yes. You should keep your normal octo 2nd stage on your primary regulator system even if you have a pony bottle with an additional 2nd stage.

Main Reason is, if you have to hand your Pony off to someone in distress, you have no backup 2nd stage. (I know you're mounting it to your tank, but most of those mounts are quick release if needed.)

Also, most folks who dive with a 19cf "slung" (not tank mounted) say to keep your valve turned off (after turning on to pressurize system). If you keep your back mount turned on, you could risk an unkown leak and end up with an empty tank. Another reason to have a 2nd stage octo on your primary reg.

 

[muddiver]

I mount my pony on my main tank too. I have it mounted valve down, valve closed. This prevents loss of air, presurizing the LP hose and I can reach down with my right hand and turn it on very eaisley. Some may argue that not pressurizing the LP hose runs the risk of getting water in through the 2nd stage. I get everything services once a year and have never had that problem.

 

[Sjassi]

Definetly. Safety first i say, and a pony bottle is easily lost under an emergency.

 

[loosebits]

I disagree with Mike S here. Needing both your octo and your pony implies a double failure (what are the chances of your buddy running out of air and then you having a failure during your ascent or having a leak in your pony bad enough to empty it that no one notices and your buddy going OOA?).

A pony essentially gives you independent doubles. I can't think of anyone who advocates three or more second stages on backmounted doubles.

Now, I would suggest you sling it and not backmount it as it gives you easy access to the valve and the ability to hand it off; more flexibility all around. I'm not sure if you can sling a bottle that small but I'm sure someone would know.

 

[mike_s]

I disagree with Mike S here. Needing both your octo and your pony implies a double failure (what are the chances of your buddy running out of air and then you having a failure during your ascent or having a leak in your pony bad enough to empty it that no one notices and your buddy going OOA?).

While I respect your difference of opinion, I wanted to ask this.

If you're worried about double chance of failure, why even have a pony or octo 2nd stage (w/o a pony on primary reg)?

A pony essentially gives you independent doubles. I can't think of anyone who advocates three or more second stages on backmounted doubles.

Assuming they are using independent 1st stages, true. (which most folks do).

Now, I would suggest you sling it and not backmount it as it gives you easy access to the valve and the ability to hand it off; more flexibility all around.

This goes though away from the indepent doubles as a slung bottle can be handed off to someone else in distress, leaving your without a redundant 2nd stage.

A lot of this can be just a difference of preference, which is what the Original Poster wanted when he said "Opinions Requested". Therefore your preference gives him another option to consider.

 

[ClayJar]

With my normal buddy, we have a procedure that if they ever have an gas failure at depth (we refuse to ever simply "run out"), the diver with the problem will go on the other's back gas at least at first. If it's a problem that can be corrected immediately, we may be able to continue the dive. If it is not correctable immediately, we can put one or the other of us on the pony for the ascent, if we so choose.

By having two second stages each, in addition to the pony I always carry, we have much more gas available in any case we may need it. Additionally, if an incident were to happen on the first dive of a series for which we were away from any potential refilling (such as having an LP hose or yoke face O-ring blow on the first dive of a two-tank boat trip), we could make the ascent sharing back gas. That would allow us to correct the problem on the surface interval and still have the pony available as redundancy for the following dive. If we went on the pony on the first dive, there may be no way to fill it (adequately) for the second dive, which would adversely impact my available redundancy options.

 

[String]

My pony/bailout is for me. My octopus is for my buddy. If a buddy needs air he can share it out of my main air supply which will always have more in it.

Mine is side slung, turned off but pressurised with the reg held with bungee cord. Rigged and used exactly as i use deco stages.

 

[loosebits]

While I respect your difference of opinion, I wanted to ask this.

If you're worried about double chance of failure, why even have a pony or octo 2nd stage (w/o a pony on primary reg)?

Not a double chance of failure but a double failure - your redundant systems failing after your (or your buddy's) primary systems fail.

Assuming they are using independent 1st stages, true. (which most folks do).

Independent doubles are two tanks not manifolded together.. the only way it works is with two first stages.

This goes though away from the indepent doubles as a slung bottle can be handed off to someone else in distress, leaving your without a redundant 2nd stage.

No, it is exactly the same. If I am diving independent doubles, I donate one reg to my OOA buddy. Now what do I breath if I have a problem? I've essentially lost that tank. The fact that it's still on my back is inconsequential. Many sidemount divers will actually donate the tank.

A lot of this can be just a difference of preference, which is what the Original Poster wanted when he said "Opinions Requested". Therefore your preference gives him another option to consider.

Yep

 

[dumpsterDiver]

I say, don't carry three second stages if they are not necessary. I solve the dilema by using an AIR 2 and having one primary second stage and one pony second stage.

Having three traditional second stages provides a certain increased level of safety, but it adds to complexity, increases the probability of failure, more cost, more maintenance and if you have a freeflow, it may take you longer to figure out what is going on.

As long as the pony is big enough to get your buddy up from the bottom, I see very little benefit to dragging three second stages around.

If you are worried about multiple simulatenous gear failures, then maybe you should put a primary and an octopus on your pony also.??? 4 regulators is better than two right? NOT