Pony use when assisting an OOA diver

[FritzCat66]

I am creating this thread to discuss an issue that came up in this thread in the Accidents and Incidents forum regarding a pony diver interacting with an out-of-air non-pony diver.


For argument's sake, to make this interesting, let's assume the following:

• Paul is a pony diver, Sam is not. Otherwise, both are single-cylinder, open-circuit divers operating within typical recreational limits (i.e. no overhead, no planned deco) and within their certifications.
• Paul did not start the dive as Sam's buddy, but was essentially diving solo - something he's certified for.
• For whatever reason, Sam unexpectedly runs out of air towards the very end of a fairly deep dive (say, 100'), after a series of dives during the day that had all the divers just about a segment away from deco on their computers, but still within limits.
• The other divers - perhaps even Sam's buddy - have already ascended or are otherwise not close enough to help; i.e. it's just Paul & Sam.
• Paul's pony is sized just about "minimally-right" for a solo diver - that is, just enough gas for him to do a normal ascent from his maximum depth with just a little bit to spare (for a couple minutes problem-solving at depth, plus a margin for breathing a bit heavier than usual) - probably a 13cf/2l or 19cf/3l pony. The pony has one reg on a 3'/1m hose.
• Paul has enough gas in his primary cylinder for his normal ascent and perhaps a little margin above that, although he's not following a strict rule-of-thirds and thus probably doesn't have enough gas for both divers to share all the way to the surface doing a normal-rate ascent with usual safety- and/or half-stops. In other words, if he is to share gas with Sam, Paul is likely to need at least some of the gas in his pony at some time during the ascent, unless ascent rules are violated.
• Paul has a typical short-hose on his primary reg and either an octo or an Air2 as his secondary.
• Paul can see that Sam is not in full-blown panic, but is obviously worried and breathing harder than usual. He has good reason to believe that Sam would use more gas than himself to make the ascent.

So, given that situation, how should Paul best help out Sam? Switch to the pony immediately and give Sam his primary reg? Give Sam the pony reg or the entire pony? Both share the primary cylinder until shallower and then switch himself to the pony?

Should Paul behave differently if his pony were slung vs. backmounted? Should Paul behave differently if he had a long primary hose, or long octo hose, vs. an Air2? What if the pony itself had a longer hose?

Or should they just violate normal ascent rules (this being recreational, open-water diving after all)? Would it make any difference how this is handled if the ascent were likely to be "rough" (e.g. hanging on an upline in strong current, strong surface current, choppy seas, etc.)?

I'm interested in hearing other divers' - especially other pony divers' - constructive opinions on how Paul should best handle this situation. I am trying to setup a hypothetical situation where Paul isn't doing anything "wrong" except perhaps pushing his gas margin on his primary cylinder, when this unplanned situation involving another diver OOA erupts (at the worst possible time, of course).

Now, I can already anticipate SB responses regarding how this situation "shouldn't" happen, but let's just assume it has. And please, I am only interested in hearing from other pony-friendly divers on this; I'm well aware of the "why use a pony?" or "if you use a pony Yer Gonna Die" arguments out there, but this question specifically revolves around someone who has already opted to carry a pony, so please just sit this one out if that's your angle.

 

[Jax]

Good Job on putting the brakes on the "shouldn't need a pony" and "shouldn't happen" crew; let's hope they listen . . .

You have a confusion factor in this:

Paul has enough gas in his primary cylinder for his normal ascent and perhaps a little margin above that, although he's not following a strict rule-of-thirds and thus probably doesn't have enough gas for both divers to share all the way to the surface doing a normal-rate ascent with usual safety- and/or half-stops. In other words, Paul is likely to need at least some of the gas in his pony at some time during the ascent, unless ascent rules are violated.

If Paul has enough for his own ascent, he wouldn't need the gas in the pony. He would ascend immediately, control his breathing, and have Sam breath off the pony. Given that the 13cf would probably run out before surfacing[1], Sam should ascend slightly faster than 30 fpm and perhaps shorten his safety stop.

[1] assume a SAC of 1cf/min, at depth is 1 * 4ata = 4cf/min, and 30ft/min = 3.33min, 4 cf/min * 3.33 min = 13.32cf; that kills off the 13cf bottle . . . too close for comfort. Yes, he won't be sucking 4cf/min the whole way, but still . . . .

 

[fire_diver]

So, given that situation, how should Paul best help out Sam? Switch to the pony immediately and give Sam his primary reg? Give Sam the pony reg or the entire pony? Both share the primary cylinder until shallower and then switch himself to the pony?

Hand Sam the pony reg. If front mounted, hand off the pony assuming Sam is breathing well from the reg, and there is a place to clip to his BC.

Should Paul behave differently if his pony were slung vs. backmounted? Should Paul behave differently if he had a long primary hose, or long octo hose, vs. an Air2? What if the pony itself had a longer hose?

No, OOA diver gets the pony when there is not enough for 2 safe ascents with back gas.

Or should they just violate normal ascent rules (this being recreational, open-water diving after all)? Would it make any difference how this is handled if the ascent were likely to be "rough" (e.g. hanging on an upline in strong current, strong surface current, choppy seas, etc.)?

When facing a low on air ascent, the surface is where they need to be, as long as they can safely get there.

I'm interested in hearing other pony divers' opinions on this.

My responses in red.

 

[FritzCat66]

You have a confusion factor in this:

If Paul has enough for his own ascent, he wouldn't need the gas in the pony. He would ascend immediately, control his breathing, and have Sam breath off the pony.

Yup, good point - I edited the conditions a little bit, so now:

In other words, if he is to share gas with Sam, Paul is likely to need at least some of the gas in his pony at some time during the ascent, unless ascent rules are violated.

and

Paul can see that Sam is not in full-blown panic, but is obviously worried and breathing harder than usual. He has good reason to believe that Sam would use more gas than himself to make the ascent.

I want to create the condition where Paul has real doubts that the primary cylinder can get both of them up normally.

This probably does not affect your suggested response, however.

 

[seaducer]

I'll second fire divers response. I would hand off the pony and let him go. I have been in one situation where an OOA diver came to me for help, it worked just like in class, however I am not sure all go that smoothly so by slinging the bottle I can get some distance if I need to.

I would blow off any safety stop unless there is plenty of gas and everyone is calm. Hitting the NDL on a rec table should still allow you to surface straight away, and regardless it is easier to unbend than undrown.

Since Sam is not Paul's buddy, I assume they don't know each other. I am not personally comfortable with someone I don't know going OOG and then being attached to me and my air supply, I don't know how they will react. I figure Paul feels the same way and so he might be much more stressed if Sam is not able to seperate with the pony, and use more gas as well.

If I could not hand off the pony I would try to manage the ascent on backgas for us both, if I dropped below 500 PSI I would switch to my pony and let Sam have the rest of the primary, when that runs out it is CESA for Sam, should paid more attention buddy. Of course that is from my big comfy chair, in reality I probably would buddy breathe with him till we both had to CESA.

If Sam flips out and I can't hand off the pony, I head back to depth and let Sam figure it out on his own, perfoming a rescue if needed once he calms down, I won't let him drown us both. Of course this is the reason I sling my pony, so I can give him all that air and keep me and mine safe.

YMMV

 

[2 Big 2 Fail]

I'm hardly someone to ask, but it seems to me that Paul has two air sources, either of which will, at that moment, get him to the surface with every expectation of being healthy. He doesn't know Sam or his normal air usage, and whatever it normally is, it's now abnormally high. Breaking it down:

If Paul can give Sam his pony, if possible, and leave him to his own devices, Paul can almost certainly make it up okay. Or he can give Sam his pony and try to shepherd Sam up under control as far as that gets him.

If Paul keeps his pony (or has to keep it) and lets Sam breath it, he may have to ascend more rapidly than he would like if Sam sucks it all down too early, because Sam's gonna want to share the primary and won't take no for an answer, because this is really just sharing all Paul's air. Paul's pretty much committing to ascend according to Sam's needs or Sam's panic, so he needs to manage the ascent to avoid the underwater fight. It would seem likely that the limited risk of the ascent is less than the risk presented by Sam underwater.

If Paul let's Sam breath Paul's primary, the same might happen, but at least a bit later in the ascent. Same risk trade-offs.


Paul can, of course, let Sam try to figure how to Zen himself up 100 feet with anything like a pulse.


What are most divers likely to do. I suspect most, if not nearly all, would consider that they're barely within limits and balance the risk of early ascent against helping Sam and share their total air and try to time the ascent so they make the surface with the last of the air and keep showing Sam the depth gauge and shooting lots of okay signs at him to keep him rational. If you want to get real calculating, I suppose you could have the two of you breath the primary first and then the pony. If the pony gives out and Sam bolts, he likely won't remember that the primary has probably recovered a bit during ascent, and Paul can use the remainder.

But that's getting carried away. Can't they likely make it okay if they just come on up and don't do the lethal stuff others have done, like try to swim to the anchor line or against current? Paul plays guts poker here, of course, betting on Paul's self control.

I suppose in the end, the lesson is that how you carry a pony expresses something of how you're prepared to use it.

 

[Elvistheking]

I thought pony stood for Piss Off Not Yours, so surely:
1. Put Sam on you Octo (or primary if using primary donate because of long hose/air2).
2. Paul swaps to Backup (if using primary donate)
2. Once sam is happy and calmed down Paul swaps to Pony
3. Ascend.

(But I'm on twins so strictly speaking not allowed to comment)

 

[FritzCat66]

I thought pony stood for Piss Off Not Yours

Hadn't heard that one before!

Any constructive comments are certainly welcome. I edited the language to be more inclusive.

 

[Jax]

I'll second fire divers response. I would hand off the pony and let him go. I have been in one situation where an OOA diver came to me for help, it worked just like in class, however I am not sure all go that smoothly so by slinging the bottle I can get some distance if I need to.

I would blow off any safety stop unless there is plenty of gas and everyone is calm. Hitting the NDL on a rec table should still allow you to surface straight away, and regardless it is easier to unbend than undrown.

Since Sam is not Paul's buddy, I assume they don't know each other. I am not personally comfortable with someone I don't know going OOG and then being attached to me and my air supply, I don't know how they will react. I figure Paul feels the same way and so he might be much more stressed if Sam is not able to seperate with the pony, and use more gas as well.

If I could not hand off the pony I would try to manage the ascent on backgas for us both, if I dropped below 500 PSI I would switch to my pony and let Sam have the rest of the primary, when that runs out it is CESA for Sam, should paid more attention buddy. Of course that is from my big comfy chair, in reality I probably would buddy breathe with him till we both had to CESA.

If Sam flips out and I can't hand off the pony, I head back to depth and let Sam figure it out on his own, perfoming a rescue if needed once he calms down, I won't let him drown us both. Of course this is the reason I sling my pony, so I can give him all that air and keep me and mine safe.

YMMV

I'm not following this, could you expand?

500psi . . . in what, an AL80? 78cf/300psi = .026 . .026cf * 500psi = 13 cf .

You have two equal air supplies at that point - why have Sam go on your back gas? or why give him any back gas at all?

 

[Jax]

One assumption that might not be a good one . . . If one follows the tenet that in a solo dive, a pony is not to be used, thought of, or any way considered into gas management, that it is for emergency use only . . . then you hand off the pony and thumb your dive because you no longer have a redundant air supply.

(And pray on the way up that you don't blow an LP hose or have a free flow or . . . . )