redundancy or failure point?????

[NAM001]

SO I GATHER THAT YOU HAVE THE PONY valve open all the time so you can smoothly shift from back gas to pony?????? I would think that you would have the pony valve shut and open only when needed to insure what when shifting yo are dong so to a tank with air in it ???

Thank you for all of the excellent input,I failed to mention some important info.I wear the pony reg on a necklace and my bottle is mounted coming off of my cam strap.I wanted to clarify that it NOT slung.

---------- Post added January 1st, 2013 at 09:50 PM ----------

Its interesting that you reference the ability to hand off the pony botle to I assume someone else. What do you have for a secondary at that point. I ask this mostly because I have not takes a solo course. Secondly in a normal set up you aways know how much gas you have available on your octo becuase you are checking routinely the back gas psi. Having the pony reg on a necklace makes it hard to pass off to another and if the reg is never needed you dont know what psi you have in the pony tank, (if needed) unless you add that to the list of periodic checks you are making while you are diving. Perhaps my thinking is more in line for stage or deco applicatons. If the pony valve is closed it them becomes of no use to you if you need it untill you open the valve. Seems like the pony would be slung with tied off reg that could be pulled loose and valve turned easily if needed. You can only check the operaton of the pony bottle somany times (predive ect) before you only have a 13 pony.

The SDI solo course recommends eliminating the octo (and I have) because it's unnecessary (see next paragraph before you sputter a response), an additional failure point (not so much), and (probably most important) is one more thing hanging that can get tangled.

The 2nd stage on the pony should be positioned in the same place an octo would be (where an OOA diver would look), should be yellow (familiar octo color), and should be easy to pull free. Also the pony should be easy to hand off. Also, it should be frequently practiced with while diving to insure a calm, collected, trained response to an emergency.

 

[dumpsterDiver]

Why do you feel an air 2 (a 2nd stage) is OK but a conventional 2nd is wrong? It seems to me that an sir 2 suffers, to one degree or another, from all the possible problems you cite in your "Answer".

Good questions... First, the Air 2 will NEVER be confused with another second stage. Divers have killed themselves when mixing up too many second stages. Some divers may have trouble with just two, but three is asking for trouble in this regard. Tech divers are using stage bottles were they can see and manipulate the valve and the second stage and hose, so this confusion issue is much less for tech divers compared to a solo diver using a back mounted pony bottle.

Second, the Air 2 can be very rapidly disconnected in an emergency. This negates some of the danger of a freeflow and loss of primary gas.

Third, the Air 2 allows me to do shallow bably dives with a buddy and still follow PADI standards and carry no pony bottle.

Fourth, the Air 2 serves as an inflator and a second stage, so even though it is an additional second stage, the hose and some sort of device must be there to inflate the BC anyway. So from a risk/reward perspective.. it has an additional function that a third second stage does not provide. In other words, the hose to the Air 2 is NOT an additional failure point like a third hose to a conventional second stage.

Fith: The AIR 2 is NOT an entanglement hazard comparable to a third second stage.

Sixth: Where the hell do you stow, 3 second stages?

And lastly: The Op did not ask about an Air 2, i am NOT advocating that it be used or is the best choice for everyone, but I thought it might put my comments in context, since I was describing the way i dive solo. I have never had any solo training or recall reading any solo diving books.

 

[aquaregia]

Its interesting that you reference the ability to hand off the pony botle to I assume someone else. What do you have for a secondary at that point.

If you donate your octo you're in the same spot. I think there's a practical limit to the number of OOG divers you need to plan to help per dive.

 

[Kharon]

SO I GATHER THAT YOU HAVE THE PONY valve open all the time so you can smoothly shift from back gas to pony?????? I would think that you would have the pony valve shut and open only when needed to insure what when shifting yo are dong so to a tank with air in it ???

Why wouldn't the pony have air in it just because the valve is open??? With the 2nd stage on my shoulder I would certainly notice any free flow and once controlled would check the SPG - but that has never happened. Unless I breathe the pony down during the dive I surface with the same amount of air as when I descended. Also, opening the valve and then closing it and purging the 2nd on each dive uses only a tiny bit of air so no real loss over multiple dives. Same with a couple of test breaths.

Its interesting that you reference the ability to hand off the pony botle to I assume someone else. What do you have for a secondary at that point.

At that point we would both be ascending, taking a safety stop, and then surfacing. Not sure why I would need an additional secondary. Are you saying that there would be 2 divers OOA that I'd have to supply?

Secondly in a normal set up you aways know how much gas you have available on your octo becuase you are checking routinely the back gas psi. Having the pony reg on a necklace makes it hard to pass off to another and if the reg is never needed you dont know what psi you have in the pony tank, (if needed) unless you add that to the list of periodic checks you are making while you are diving.

See above. The pony is always full. Why would I need to periodically check it unless I was using it, in which case I would be checking it and not my main tank.

If the pony valve is closed it them becomes of no use to you if you need it untill you open the valve.

That's why the valve is open on a dive.

Seems like the pony would be slung with tied off reg that could be pulled loose and valve turned easily if needed. You can only check the operaton of the pony bottle somany times (predive ect) before you only have a 13 pony.

Not sure what you are saying here. My 2nd on the pony is held by an octo holder from which it can be easily pulled free and handed off. The pony is clipped to my BC and can be unclipped and handed off - thus freeing both divers - we are not tied together - much easier to make a clean ascent. The valve is always on. As, above turning the valve on before submerging and then off after surfacing and then purging uses almost no air. Nor does breathing it a few times pre-dive. In any event, it can be easily topped off from another tank or at the fill station as necessary.

Finally, my pony is 13 cf. All calculations (ascent from rec depth at 2X my SAC with 3-5 min safety stop) tell me I will have a bit of air left. Actual practice dives have confirmed that. That's not to say, when diving solo, I might not get tangled, have an equipment (main tank) failure, drop both my knives, and have the pony fail. If that happens - well I guess somebody just hates me.

 

[NAM001]

I think that perhaps i am looking at it from the wrong perspective. SOLO you would never have to hand off a pony to anyone. So hand off being moot you dont loose the secondary ever. I am still not sure about havng the valve on , on the pony all the time as a slow leak over time would deplete/reduce the gas in the second air source.

When i was looking into taking the solo course....I believe you have the option of diving doubles isolated or carry a pony, in which case both tanks would be turned on. A Y or H valve did not qualify as a second sir source However it did proivde redundancy air path.

In that case a slight leak would not deplete the back up air source very fast and each fill it would be topped off, unlike a pony bottle. I guess i will have to do some reading on the matter. A lot of regs because of design or wear, have leaks at the first stage and there is just not a lot of volumn in a pony 13. My other thought is that some mount the pony on the back gass tank, in which you would never know if there was a leak that was running the psi down without an spg. The idea of the pony to me is an emergency backup air source not a replacement for the backup secondary. I thnk the assumption for the pony being always full may be a flawed thought process. Just because you are not using the pony does not mean the psi is not dropping. A slow leak in a tank valve oring or an out of adjustment secondary or a leaky secondary hose, that occasional free flow when first jumpng in will run a tank down over several dives. Especially a 13. Then again I need to do some reading on the logic. I sling a 13 also for shallow solo dives. the valve is closed. I test the reg on land and close the valve, then jump in crack the valve and breath the 13 and then close the valve again. I doesnt take very many of those sequences before the psi has dropped 500. It has been a long time since I have used the pony for solo since i have a set of double 50's that i am working out the solo issues with. In support of your osition out of air is no air at the mouthpiece. A secondary reg is useless if the problem is the common 1st it is hooked to. The other aspect is that if you have a free flow you cant isolate the tank and have a working socondary unless youare using an H valve or Y valve to privide redundant 1st's. even with that you can continue to breath the free flowing reg and fin towards the surface while turning on the pony for the safety stop. Like i said i have some reading to do i guess.

Why wouldn't the pony have air in it just because the valve is open??? With the 2nd stage on my shoulder I would certainly notice any free flow and once controlled would check the SPG - but that has never happened. Unless I breathe the pony down during the dive I surface with the same amount of air as when I descended. Also, opening the valve and then closing it and purging the 2nd on each dive uses only a tiny bit of air so no real loss over multiple dives. Same with a couple of test breaths.



At that point we would both be ascending, taking a safety stop, and then surfacing. Not sure why I would need an additional secondary. Are you saying that there would be 2 divers OOA that I'd have to supply?



See above. The pony is always full. Why would I need to periodically check it unless I was using it, in which case I would be checking it and not my main tank.



That's why the valve is open on a dive.



Not sure what you are saying here. My 2nd on the pony is held by an octo holder from which it can be easily pulled free and handed off. The pony is clipped to my BC and can be unclipped and handed off - thus freeing both divers - we are not tied together - much easier to make a clean ascent. The valve is always on. As, above turning the valve on before submerging and then off after surfacing and then purging uses almost no air. Nor does breathing it a few times pre-dive. In any event, it can be easily topped off from another tank or at the fill station as necessary.

Finally, my pony is 13 cf. All calculations (ascent from rec depth at 2X my SAC with 3-5 min safety stop) tell me I will have a bit of air left. Actual practice dives have confirmed that. That's not to say, when diving solo, I might not get tangled, have an equipment (main tank) failure, drop both my knives, and have the pony fail. If that happens - well I guess somebody just hates me.

 

[Stealth Mode]

I do have a button gauge to verify that it is full before every dive.No need to hand it off on a solo dive.As for valve on or off I always have it on.I KNOW thats not the case for deco.My pony is used as backup.When im diving solo I do roll over frequently to see if im streaming air from my back,also I heard of someone here carrying a mirror when solo diving I thought that was a good idea.And to clarify I have a 19 cf pony which I have tested from 70 feet deep making a SLOW ascent and sitting through a 5 min safety stop with plenty of air left.Now granted that test wasnt conducted in full panic mode.I am really enjoying the feed back here EVERYONE has made some very valid points in this discussion.The reason I dont sling my pony is because during spear fishing my shock cord always seems to snag on something on the sides of my BC never in the front or back although thats probably just coincidence.Keep em coming please people.

 

[Kharon]

I think that perhaps i am looking at it from the wrong perspective. SOLO you would never have to hand off a pony to anyone. So hand off being moot you dont loose the secondary ever. I am still not sure about havng the valve on , on the pony all the time as a slow leak over time would deplete/reduce the gas in the second air source.

Not the wrong perspective, simply the totally wrong assumptions.

First, anytime there are other divers in the water you may need to share air - solo diving or not - possibly with someone not your buddy even when you have one. If you are not prepaired for that you should be on the surface snorkeling.

Second, once you are dealing with an OOA emergency having a 3rd second stage is what is moot. You simply don't need it. What don't you understand about that?

Third, I was taught to do a bubble check at about 5 feet before descending. If you are diving a reg (or any other part of your kit - hoses, SPG, BC, inflator) that has a leak (slow or not) you are a fool. Get it serviced. My kit does NOT leak - not one bubble - else I would abort the dive and take care of it.

The only air loss is from turning the valve on and off and purging it once it's turned off (a tiny bit of air) and breathing the reg to test it before entering the water (two or three breaths) - simply not going to make a difference. If it does then your dives are vastly underplanned. A free flow will be observed, stopped, pressure checked, and the dive continued or aborted depending.

When i was looking into taking the solo course....I believe you have the option of diving doubles isolated or carry a pony, in which case both tanks would be turned on. A Y or H valve did not qualify as a second sir source However it did proivde redundancy air path.

In that case a slight leak would not deplete the back up air source very fast and each fill it would be topped off, unlike a pony bottle. I guess i will have to do some reading on the matter. A lot of regs because of design or wear, have leaks at the first stage and there is just not a lot of volumn in a pony 13. My other thought is that some mount the pony on the back gass tank, in which you would never know if there was a leak that was running the psi down without an spg. The idea of the pony to me is an emergency backup air source not a replacement for the backup secondary. I thnk the assumption for the pony being always full may be a flawed thought process. Just because you are not using the pony does not mean the psi is not dropping. A slow leak in a tank valve oring or an out of adjustment secondary or a leaky secondary hose, that occasional free flow when first jumpng in will run a tank down over several dives. Especially a 13. Then again I need to do some reading on the logic. I sling a 13 also for shallow solo dives. the valve is closed. I test the reg on land and close the valve, then jump in crack the valve and breath the 13 and then close the valve again. I doesnt take very many of those sequences before the psi has dropped 500. It has been a long time since I have used the pony for solo since i have a set of double 50's that i am working out the solo issues with. In support of your osition out of air is no air at the mouthpiece. A secondary reg is useless if the problem is the common 1st it is hooked to. The other aspect is that if you have a free flow you cant isolate the tank and have a working socondary unless youare using an H valve or Y valve to privide redundant 1st's. even with that you can continue to breath the free flowing reg and fin towards the surface while turning on the pony for the safety stop. Like i said i have some reading to do i guess.

In my opinion you are doing the "thinking" without any real grasp of the parameters and issues. My advice is to find someone who is a solo diver with a lot of experience and talk to them and get their expertise rather than blindly thrashing around assumptions which are at best incomplete and misunderstood. You are obviously most certainly not going to figure it out on your own. Get some help from someone face to face that you trust and that you will listen to. You seem to keep restating the same erroneous "thoughts" so it seems clear you're not confident in what is being said here.

 

[drbill]

I finally removed the octo from my primary reg set on the main tank. Decided I needed to look less like a Christmas tree with four second stages (main, octo, Air-2 and pony) around my chest. I never use the Air-2 as an octo (I just like the size of the inflator buttons on it). I do check both reg sets to make sure the pony reg is functioning properly.

 

[shoredivr]

Why wouldn't the pony have air in it just because the valve is open??? With the 2nd stage on my shoulder I would certainly notice any free flow and once controlled would check the SPG - but that has never happened.

Diving in a moderate current, or if scootering, you could lose gas from an open valve and not notice it immediately. Current diving may not apply to you, but it does to me. With the bottle slung, I can get to the valve easily.

 

[redacted]

A Scubapro Balanced Power Inflator has similar buttons and button configuration.