Pony Bottle: Valve On or Off while diving

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

@rfwoodvt at 30ft I would just CESA, you're nowhere near deep enough to need a safety stop, and you're well within the realm of an easy CESA if it really hit the fan to just make a direct ascent.

Either way, the pony should replace your secondary around your neck with the valve on IMO

I do understand that you specified 30 feet, and of course there is going to be some depth at which I would also agree that redundancy is silly.

But I would avoid recommending CESA in general. You are a role model with a lot of experience, and less experienced divers may remember that you suggested CESA but may not remember the exact depth that you specified.

CESA is an unforced error. It's a last resort and it involves decompression stress. There is no reason to include it in any dive plan.

If you think that a safety stop is a good idea, then you should do it, and you should be equipped to do it even with an equipment failure. If we didn't think that it was necessary, why would we recommend it on any dive?
 
And as for the on or off discussion, always on. why turn it off? takes a second to have it topped off.
During the dive?

I actually did have my pony malfunction and freeflow to empty almost once. After i had the whole top assembly replaced by the dive resort on Cebu in Moalboal for free. I did tip the guy well of course.

I think that you just made my point.
 
If a pony bottle is being used by a solo diver as his/her required (SDI and PADI) redundant air supply and it fails and free flows due to the valve being turned on and the system made ready for use, the dive is over. The diver will retreat to the surface in the same manner as the diver would do if his/her main air supply failed, end the dive. A redundant air supply for a solo diver is not a stage bottle and it is not part of the gas plan for the dive but a fail safe back up in addition to the required gas plan for the dive. The aux bottle capacity should be obviously sufficient for the expected depths or other factors.

James
 
Been musing around the idea of backup/redundant air in the form of a pony bottle for a while now and I've been wondering a few things.

Let's first start with a couple of givens:
  1. 13 ft^3 bottle
  2. Mounted on the main tank or on a Zeagle Zipper attachment on the BC (I have a ranger LTD)
  3. Stage Kit type rigging
    1. SPG
    2. DIN first stage
    3. Second stage with long hose and retainer band

For some reason one potential and routine problem that comes to mind is sudden free flow of the pony second stage, whether at the surface or just because it doesn't like the position, or losing air through an incipient leak through a loose fitting or the like.

My gut says that the pony tank valve should remain closed until needed. Of course this would mean having immediate and ready access to the valve which in turn means the tank should likely be mounted valve down.

Am I barking at the moon or is there some merit to this thought?

You didn't ask but I recommend the Shark pony mount:


Have used it on about one hundred solo dives

The attaching mechanism is fantastic and has built-in redundancy

Meaning if the primary attachment point (cam band) comes lose, the tank cannot go anywhere because its attached to the primary tank neck-valve via a J hook

The J hook goes under your first stage and therefore cannot physically become detached
 
Been musing around the idea of backup/redundant air in the form of a pony bottle for a while now and I've been wondering a few things.

Let's first start with a couple of givens:
  1. 13 ft^3 bottle
  2. Mounted on the main tank or on a Zeagle Zipper attachment on the BC (I have a ranger LTD)
  3. Stage Kit type rigging
    1. SPG
    2. DIN first stage
    3. Second stage with long hose and retainer band

For some reason one potential and routine problem that comes to mind is sudden free flow of the pony second stage, whether at the surface or just because it doesn't like the position, or losing air through an incipient leak through a loose fitting or the like.

My gut says that the pony tank valve should remain closed until needed. Of course this would mean having immediate and ready access to the valve which in turn means the tank should likely be mounted valve down.

Am I barking at the moon or is there some merit to this thought?




I have done both over the years. I sling my ponies so the valve is readily accessible so the 13 was typically closed. But now I have adjustable second stages so just detune the stage by closing the knob. I personally would not back mount a pony.
 
Why not turn it on and watch the pressure gauge, and keep the second ready for use. What good is it if it’s leaking and you need it. If it’s an essential piece of gear and it’s faulty you need to cancel the dive. If it’s not essential you don’t need it in the first place.
 
I turn mine on before I splash then close it in case it free flows after I splash.

When I reach the mooring line or anchor line I turn it on and off again, then when I'm at the bottom I repeat ensuring that it's fully charged at depth.

During the dive I will occasionally check the gauge to make sure no gas has escaped as I'm frequently in strange positions while photographing and possibly the purge button on the second stage could have released gas without my knowledge.
 
@Moerae

Fraction of the cost? If they own a pair of tanks anyway the only delta in cost is the third tank *where you have to add in about $50/yr of maintenance for hydro/vip* vs. the bands and manifold *which are cheaper than the up front cost of the third tank and have no additional maintenance since the cost of servicing the manifold is the same as servicing the third tank*.

On the rock bottom thing, if the pony can't serve for rock bottom what is the point of bringing it in the first place? If it can serve rock bottom, is it really better than proper redundancy

@doctormike hopefully they read the whole post where I tried to lead off with "if you're going from 30ft" though who knows. Frankly though this may be a legitimate use case for a Spare Air if we don't want to advocate for CESA's anymore though I do think from 30ft it's a perfectly reasonable solution to a dire emergency since you have an unltd NDL at that depth. We use the spare air's in aquaria where many of the big tanks are in the 25-30ft range.

@NAUI Wowie if I were you I would either fully sidemount *though probably not*, but instead put an AL80 on my back and another one sidemounted on the left. The one on your back takes care of long hose *since you're penetrating a wreck* and wing inflation, and the left bottle is the short hose around your neck. You dive it like you would proper sidemount and it's good for 2 dives with a better gas reserve than the other divers on both dives, takes up less room, and gives you full redundancy. Just add a loop bungee to your backplate and off you go.
 

Back
Top Bottom