Is a Pony Bottle too complicated for a beginner?

[MaxTorque]

There is, within recreational diving limits and situations, really only one reason to carry a pony:

When there is a reasonable chance that you will be unable to safely and completely carry out an air sharing scenario with your buddy at any point during your dive plan.


What drives that "reasonable" chance is of course rather varriable, from an un-reliable or simply unknown buddies to diving conditions that might render a long duration close quarters contact difficult (high current on a drift dive for example)

However, as a beginer, it's going to be a lot better on to try to avoid getting to more complex situations such as those mentioned anyway.


One "non" reason to carry a pony is because you are not very good at managing your own air supply. If you can't manage a primary supply, then adding a (small) secondary one is not going to help, it's going to hinder!

The fact the OP says they are checking their SPG very often is GOOD. As a beginer you haven't yet got the feel or experience for how fast you use your air, and you are also going to have a much more variable consumption because your buoyancy and trim will be less refined, and because you are not yet "at home" underwater. I'd say by around OW dive number 20, you should really be mostly "at home" ie not be worrying or thinking continuously about the fact you are under water, and you should by this point be able to start to estimate your consumption. Try it, look at your spg, and think, i'll look in 5min, and i think it will show a reading of "x" and do that and see ho close you are! You'l also start to have a back-catalogue of dives to look up, to say "ah yes, i did a similar dive and i used "x" amount of pressure in "y" minutes". At this point, you need to be very conservative with your basic dive planning,to give yourself room to make some small mistakes, to give your self confidence that a small error is not going to spiral out of control.

Do not use the fact you are carrying an extra cylinder to cloud your judgement or change your conservative planning at this stage of your experience.

So would i recommend a pony to a beginner, no, not really. Far better to increase your plan conservatism and to end the dive or "Go shallow" with a higher reserve air volume in your backgas. There are plenty of really good beginner dives where you drop under say 100 bar, you are already "back at the boat" because you turned the dive conservatively, but you can spend another 20 min just staying at say 5m in close proximity to the boat. Here's if you suddenly notice "oops, i'm down to 50 bar" then there is no drama, simply surface.

 

[rick00001967]

Can you be more specific about what unique difficulties originate from using a jacket BC and a tank-mounted pony bottle?

Also, you comment about the necessity to "shift gas around" when using a pony bottle is not something i understand. If the OP is talking about a 13 cu-ft pony bottle, the weight (negative buoyancy) of that tank and regulator can't be more than a couple of pounds. Why not just figure the negative weight in water and add another equivalent piece of lead on the belt, harness weightbelt or cam strap to balance? I see no need to try to move air around to account for the potential asymmetric weighting.

it seems like you are making it out to be more difficult than it is.

i only commented about making sure the bc used was able to facilitate the use of a slung tank. not all recreational bc's will have the necessary design or hardware to allow this. for example.....some only have plastic shoulder drings, some have no drings,and most do not have a waist dring.

remember it was my suggestion NOT to use a 13cf tank. if the op decides to use one, can rig a 13cf tank, and it does not cause any weighting issues than there is no problem.

but with most slung tanks there obviously will be extra weight on one side when full. when emply (depending on the tank) it may be positive. so there is obviously a weight "shift". with a jacket style recreational bc it may not be possible to move the gas around inside the bladder in order to compensate for that weight shift. with a rear inflate rec bc wing or a bp/w, you can simply roll to one side or the other and allow the gas in the wing to move from one side to the other to compensate for the weight shift.

i don't think my comment made anything sound "difficult". just takes a little practice. but when deciding to add something such as a slung pony, the op needs to know that their current gear may not accomodate it, or may not allow the most effective use.

 

[Divin'Papaw]

There is, within recreational diving limits and situations, really only one reason to carry a pony:

When there is a reasonable chance that you will be unable to safely and completely carry out an air sharing scenario with your buddy at any point during your dive plan.


What drives that "reasonable" chance is of course rather varriable, from an un-reliable or simply unknown buddies to diving conditions that might render a long duration close quarters contact difficult (high current on a drift dive for example)

I understand what you are trying to say but I don't believe you are 100% correct. Solo diving (for those properly trained, equipped and experienced) also requires some form of air source redundancy. In this instance there is no buddy for air sharing.

 

[MaxBottomtime]

Those deceased seem to magically multiply each time this fantastical myth is repeated

Not a myth.
Accident on Southern Cal Oil Rigs Dive

 

[johndiver999]

i only commented about making sure the bc used was able to facilitate the use of a slung tank. not all recreational bc's will have the necessary design or hardware to allow this. for example.....some only have plastic shoulder drings, some have no drings,and most do not have a waist dring.

remember it was my suggestion NOT to use a 13cf tank. if the op decides to use one, can rig a 13cf tank, and it does not cause any weighting issues than there is no problem.

but with most slung tanks there obviously will be extra weight on one side when full. when emply (depending on the tank) it may be positive. so there is obviously a weight "shift". with a jacket style recreational bc it may not be possible to move the gas around inside the bladder in order to compensate for that weight shift. with a rear inflate rec bc wing or a bp/w, you can simply roll to one side or the other and allow the gas in the wing to move from one side to the other to compensate for the weight shift.

i don't think my comment made anything sound "difficult". just takes a little practice. but when deciding to add something such as a slung pony, the op needs to know that their current gear may not accomodate it, or may not allow the most effective use.

Thanks for the explanation. You make some good points. The OP seemed to be asking about mounting the pony bottle on the tank rather than wearing it slung, so the issues you raised with a jacket BC don't seem to come into play in this particular situation.

The weight shift associated with the use of a 13 cu-ft pony bottle, which is what the OP seemed to be inquiring about; is probably less than one pound, so I guess we are in agreement that the change is pretty negligible.

So it seems like your advice to buy a BP/W or rear inflate BC is applicable if the diver wants to use a larger pony bottle than he mentioned AND wants to mount it in a different location (side slung) than he was initially considering.

In my experience, rigging a side slung pony bottle IS more complicated. It does have the potential to get in the way and if not done properly with the right adjustments, d-rings, clips and locations, then the bottle can be all over the place and smack you in the face on entry and be quite bothersome underwater. So I agree that side slinging a stage bottle, really does need to be done properly.

On the other hand, a back mounted pony (although it has some significant disadvantages) is a lot simpler and easier to dive with - even with a rather rudimentary mounting system located on the main tank. In addition, in my experience, it can be done equally well with a normal jacket BC or a BP/W.

 

[wetb4igetinthewater]

And what happens if your pony reg freeflowed during the dive and you hadn't noticed?

How would you not notice? I put my pony's reg on a necklace around my neck. My alternate was clipped off inside the triangle.

What would happen if you forgot to fill the pony, or forgot to open the valve before the dive and couldn't reach it when you were out of air?

Pre-dive checks. Breathing off all regs to ensure they were functioning.

 

[MaxBottomtime]

How would you not notice? I put my pony's reg on a necklace around my neck. My alternate was clipped off inside the triangle

Not everyone does that. Some clip the pony reg elsewhere, some have it banded to the tank itself. Second stages can and do leak. Sucking down your primary tank and reaching for an empty backup can ruin your day.

 

[wetb4igetinthewater]

Not everyone does that. Some clip the pony reg elsewhere, some have it banded to the tank itself. Second stages can and do leak. Sucking down your primary tank and reaching for an empty backup can ruin your day.

Well, that's a training issue. Possibly a discipline one. For the latter, that's where Darwin steps in.

 

[Jayfarmlaw]

A beginner cannot know that. This is partly why there are so many people who say how rubbish their initial training turned out to have been when they see proper divers.

I agree that there are a lot of OW cards given out for the cost of the course, however, any student SHOULD be able to get in a pool and go through their basic skills with whatever minor change to their equipment they implement. If the pony interferes with reg recovery or any other basic skill it will be obvious and can be worked through.

I think this is an equipment solution to a skills problem, but I also support redundant air.

It’s a 13cf pony, not going side mount, a DPV, or some other radical equipment change so I disagree that even a new, properly certified, diver won’t know when something is not working and should be able to work through the solution. I guess some agency could develop a “Pony Bottle Diver” card, charge them $300 for a pool dive to go though the basic skills with a DM and their Extra Large Spare Air.

I see your point and agree that some new Divers should never have been issued a card, but I tend to give most instructors, even the resort instructors, the benefit of the doubt. I'd like to think all the students I have helped could adapt to a 13cf pony bottle without much trouble.

Jay

 

[KenGordon]

I agree that there are a lot of OW cards given out for the cost of the course, however, any student SHOULD be able to get in a pool and go through their basic skills with whatever minor change to their equipment they implement. If the pony interferes with reg recovery or any other basic skill it will be obvious and can be worked through.

I think this is an equipment solution to a skills problem, but I also support redundant air.

It’s a 13cf pony, not going side mount, a DPV, or some other radical equipment change so I disagree that even a new, properly certified, diver won’t know when something is not working and should be able to work through the solution. I guess some agency could develop a “Pony Bottle Diver” card, charge them $300 for a pool dive to go though the basic skills with a DM and their Extra Large Spare Air.

I see your point and agree that some new Divers should never have been issued a card, but I tend to give most instructors, even the resort instructors, the benefit of the doubt. I'd like to think all the students I have helped could adapt to a 13cf pony bottle without much trouble.

Jay

At least one fatality on the BSAC incident report was a person jumping in on a pony, running out of gas in 5 minutes or so and drowning. That was not a novice. They have extra risks and until the diver is half competent they are not equipped to deal with them. 95% will be fine as 95% of divers get away with bad practice, but they will be more task loaded pointlessly.

Did he say a 13cf pony? That is not a pony, that is a suit inflate bottle.

Edit he did and he has one already. Oh well. Never mind,

OP you need to learn how to calculate how much gas you need for a given dive yesterday. You will have to work out how deep you can use that pony from and still get to the surface with something to breath. First you will need to establish a typical breathing rate over a few dives, add a bit for being in a bit of mess when you find you are out of gas and the integrate that between the depth and the surface,

Say you consume 25 l/minute at the surface, you have 400l in your cylinder so 16 surface minutes.
Starting from 30m and ascending at 10m/m you will take 3 minutes at an average depth of 15m so 2.5 bar. That is 3 * 2.5 bar minutes or 7.5 bar minutes.. you have 16 So if everything goes well you can make it, assuming no stops and no sorting out time at depth. One minute of sorting out at 4 bar means you are up to 12 ish, a slower ascent, say 7m/minute and you are out.

How fast can you ascend? Do you know? Do you feel lucky?