Question about pony bottles

[doctormike]

Of course I'm planning for separation. If we are separated and my son has a main tank failure, he has a pony on his back. If we are separated and I have a main tank failure, I have a pony on my back. We follow standard procedure for separation. If we are separated and we are diving a single tank with octo, and one of us has a failure, where does that leave us??? EXACTLY one of the reasons I think a pony would be superior to the single tank w/octo. AM I MISSING SOMETHING???

I am NOT planning for every scenario presented to me here in this thread, and currently I have no intention of planning for such. As previously noted, we have 40 dives as certified divers. We've done 15 resort dives before that. I'm planning for my son and myself. Not even going to consider if my son is separated, and suddenly another diver needs my pony at the same time my main fails, only to discover that my pony doesn't have any air in it because I've been breathing from it the whole dive, when I suddenly discover that my left fin is on my right foot...

Yes, that's exactly my point. You are choosing a pony based on the volume that you both have combined, assuming no buddy separation, but you are also claiming that you are planning for buddy separation:

There are two pony bottles, we're buddy diving. That's 38 cu ft, not 19, of reserve air.

Perhaps I have said something to upset you, you seem to be responding is a somewhat defensive manner. You have 40 dives in your log book, and you started this thread by asking if you were missing something. You have some experienced divers offering pretty standard advice about how to rig a pony and how much gas to carry, and you seem to want to make this into a debate, responding to these points with counter-arguments. Of course, I'm not saying that we are necessarily right or that you haven't thought things through or done your research. But if you are going to ask for advice, maybe be a bit more open to ideas that you hadn't already thought of.

A lot of the "standard" gear configuration advice comes from the tech world. Many recreational divers reject this advice because they think that it only applies to technical diving. This is not wise. Technical divers obsessively optimize their gear based on real world experience and accident analysis, and there is a reason why most tech divers tend to use fairly similar approaches, and why most tech agencies recommend similar gear configurations. Most of these optimizations apply just as well to recreational diving. So take that for whatever it's worth...

It's nice that you are diving with your son, I do that too and it's a blast...

Safe Diving!

 

[T.C.]

I doubled our sac rate. As it happens, I've been overexerted from just about what your talking about; swimming upstream to get my son who had gone ahead of me in a rapid chase for critters. I found it really handy to have that data from my computer download.

Just what is that baseline SAC rate? Computers usually don't figure a minute to minute SAC rate, it's usually computed over the course of a dive.

Second, hard swimming probably does not equal the rate that a panicked diver can suck air. If you son panics, he can probably use 3-4 times his normal air rate. You can use even more. We I train at my max breathing rate my SAC is 5 times my normal use (2.5 cu ft/min vs. .5 cu ft/ min).

My my point is that if one pony is depleted, why not have the ability to supply a diver from an Octo? This isn't an either/ or configuration. You can have both a pony and an Octo. Why not be prepared for a wide range of emergencies?

 

[Searcaigh]

For what its worth, I dive with either a side slung 13 cu ft pony or a 30 cu ft stage depending on the dive;

With a single back mounted tank I have no octopus for local diving, however when I travel and cannot hire a pony the pony second stage is removed and fitted to my normal first stage.

I have used a pony with it mounted on my tank and to be honest I found that upset my buoyancy more that having it side slung, and like doctormike I also lug around a heavy housed SLR with double strobes.

Whatever you chose to do just practice with it so both of you are well trained should the need arise to use the ponies, but try side slinging and notice how easy it is to use, especially for opening the pony valve.

Enjoy your diving with you home grown dive buddy

 

[Txredneck]

I have my computer set for 30 second sampling. For any 30 second period, or a minute period, or 2, 3, 4 minute period, whatever period of the dive, can be calculated by the psi drop during that period.

 

[drbill]

As I age, I do find that carrying my 19 cu ft pony mounted to my main tank becomes a bit more difficult... but losing my life would pose even greater difficulty. Most of my diving the past 2-3 years has been at relatively shallow depths (above 60 fsw) to achieve greater bottom time for filming. I generally do not carry my pny on those dives even though I am solo because I have done emergency ascents from 80-90 ft in the past (although not with any deco obligation). When I resume deeper diving, I will reattach my pony.

Even on the rare occasions when one of my "regular" buddies is available to dive with me, I like carrying the pony if going to depth since we are usually two imagers focused on our subjects rather than one another. If you and your son make a good buddy pair and remain close to one another so each of you is able to react to a problem, then you may not need a pony.

 

[redacted]

Lastly, in my opinion, 6 cu ft is too small for an emergency supply. That panicked diver will be sucking down air, probably at a rate of 1 cu ft/min or faster. At that rate, on the surface, that 6 cu ft tank will last 6 minutes. At 90 feet, it will last a little over 1 minute. 19 cu ft is a very common size, and was a good choice.

Why do you assume a diver will panic when he is forced to rely on his planned and practiced redundant gas source?

Many folks assume that people panic when they get shot at. Do you panic? Do you assume your peers would panic?

 

[rhuntley]

Why do you assume a diver will panic when he is forced to rely on his planned and practiced redundant gas source?

Many folks assume that people panic when they get shot at. Do you panic? Do you assume your peers would panic?

You can't go wrong preparing for the worst.

 

[Txredneck]

Yes, that's exactly my point. You are choosing a pony based on the volume that you both have combined, assuming no buddy separation, but you are also claiming that you are planning for buddy separation:





Perhaps I have said something to upset you, you seem to be responding is a somewhat defensive manner. You have 40 dives in your log book, and you started this thread by asking if you were missing something. You have some experienced divers offering pretty standard advice about how to rig a pony and how much gas to carry, and you seem to want to make this into a debate, responding to these points with counter-arguments. Of course, I'm not saying that we are necessarily right or that you haven't thought things through or done your research. But if you are going to ask for advice, maybe be a bit more open to ideas that you hadn't already thought of.

A lot of the "standard" gear configuration advice comes from the tech world. Many recreational divers reject this advice because they think that it only applies to technical diving. This is not wise. Technical divers obsessively optimize their gear based on real world experience and accident analysis, and there is a reason why most tech divers tend to use fairly similar approaches, and why most tech agencies recommend similar gear configurations. Most of these optimizations apply just as well to recreational diving. So take that for whatever it's worth...

It's nice that you are diving with your son, I do that too and it's a blast...

Safe Diving!

No I did not choose a pony based on both bottles. Read the whole post. In the past I've planned to begin ascent when we get to 35 cu ft (obviously that # changes with depth, but that's about the average). That's enough air for 2 divers, one of them being out of air. What I posted was that with one OOA situation we would have 38 cu ft of air in two pony bottles, AND the 35 cu ft of air in the one remaining main. 73 cu ft reserve if we use ponies, whereas in the past dives if there were an OOA situation on one of the mains we would have had only 35 cf remaining. Under an extreme case of simultaneous OOA mains, we would still have the two ponies with 38 cf, whereas without the pony tanks and a doulble OOA, we would have nothing. And the situation that worries me the most, if you go back and read my comment about how my son used to just swim off with out signalling me, when I would look away for just a few seconds and he'd be hightailing it away from me chasing after something, separation. In such a case without a pony, we're SOL. At 80 ft, 19 cu ft of air will get one of us to the surface at 60 fpm to 60 fsw, then 30 fpm from 60 to the surface. In a panic situation it is still enough to ascend 80 ft at 30 fpm with no stops. If we're at 80 ft, we'll be on nitrox 32 to begin with.

Some have suggested that I should be perfecting our buddy skills, not buy new equipment. I have agreed with that. We should be perfecting our buddy skills, and we are. We improved that dramatically from our beginnings. That being said, I don't want to sling the bottle because that's a quite a change from what were used to. Mounting it puts our pony reg exactly where we are already programmed to look for our octo, and it doesn't put any new equipment down in front of us that we're not used to. Later down the road, certainly we may try out side mounting, slinging the pony and what not. But these things require additional learning training, and were already busy with learning and training.

I hope you can understand: I never asked what is the BEST system. What I was asking; Is this better than what we are doing (single tank w/octo)?

As far as the suggestions of primary, octo and pony regulator, that's a consideration. I will likely have that setup on our dive trip this weekend.

 

[uncfnp]

Why do you assume a diver will panic when he is forced to rely on his planned and practiced redundant gas source?

Many folks assume that people panic when they get shot at. Do you panic? Do you assume your peers would panic?

I think rather than a panicked sac rate it's better to look at it as a stressed rate. Even the most experienced and seasoned diver is likely to experience at least some brief increase in respiratory rate as he/she deals with the unexpected.

 

[Diving Dubai]

Some have suggested that I should be perfecting our buddy skills, not buy new equipment. I have agreed with that. We should be perfecting our buddy skills, and we are. We improved that dramatically from our beginnings. That being said, I don't want to sling the bottle because that's a quite a change from what were used to. Mounting it puts our pony reg exactly where we are already programmed to look for our octo, and it doesn't put any new equipment down in front of us that we're not used to. Later down the road, certainly we may try out side mounting, slinging the pony and what not. But these things require additional learning training, and were already busy with learning and training.

I hope you can understand: I never asked what is the BEST system. What I was asking; Is this better than what we are doing (single tank w/octo)?

As far as the suggestions of primary, octo and pony regulator, that's a consideration. I will likely have that setup on our dive trip this weekend.

I do see where your coming from, but think your're being a bit blinkered. I carry a 40cf side slung. My main tank has both a primary and a secondary bungied around my neck. My stage has a separate reg with the hose bungied which sits next to the pressure gauge. The valve has an indicator collar which shows red for closed, green for open. I always dive air in the stage (unless I'm doing a deco dive) because if I hit a down current which takes me below my MoD for my nitrox mix I can switch - but that's my local conditions.

So with my rig, I have a standard October with primary and secondary - if I travel or dive shallow no chane required. I have in my view a pressure gauge for the bail out, which you don't have on a rear slung. My stage can be handed off if need be, and of course it has 40 cf - no one ever died of too much gas!!

i think you're limiting yourself with a 19cf, your excuse about equipment familiarity doesn't add up.. A back slung will require changes too. Perhaps your son or you could go yo a 30 cf if you don't feel happy with a 40. The choice of splitting your regs is up to you - although you still need another 1st stage each so why not get another reg each too?

In your scenario your limiting yourself to only buddying with your son or vis versa. What happens if you both get another buddy and they go OOA? You have 19cf to get a stressed diver to the surface, maybe they're tangled in fishing line....

anyway, these are your choices. Lots of experienced people have offered their advice, whether you take it or not is down to you