Pony freeflow

[Atticus]

As a partial answer to your question --

I teach open water students in frigid (40F) water. We don't give them back mounted pony's, but they do have standard second stage octopus regulators. These are medium quality regulators not specifically designed for cold water (yes I'm aware of cold water regulators and use them myself; this is rental gear . . .).

It's a rare weekend when we don't have a couple of free flows that need to be addressed. This is no big deal since we might lose a cube or two before getting it under control.

However with a small pony bottle, if your bailout margins are small and/or if you don't notice the free flow as quickly due to the location of the 3rd second stage then you might be counting no a resource which is no longer viable.

 

[CRDiver]

Jeesh man, relax. I gave you several reasons for freeflows, why they happen, and how to deal with them based on which type of mount you do. I'm not trying to sell you anything. I answered your question.

1st stage problems don't happen all that often, but they do happen. They are typically caused by a hp seat failure. 2nd stage freeflows are more common. They happen from the cracking pressure being to low, or a particle lodged in the membrane, keeping it from fully closing. Charging the system, and then shutting it down is a preventative way of handling it. You must have missed it.

If you do a lot of cold water diving, you already know about free flows from freezing.

Yes, I already know about the causes of freeflows, and that is why I didn't ask about them, or how to handle them, or which mounting method was better. I was asking about the frequency of freeflows for those using backmounted ponies, without judgment or criticism.

 

[mempilot]

Reread your question. BTW, where do see any judgement or critisism? I could care less how you mount your pony. I answered your question.

How many people here who use a backmounted pony left on during the dive have had the pony reg freeflow, and what were the causes of the freeflow?

 

[CRDiver]

Sorry if I was unclear about causes - I'm looking for case specifics, not the standard laundry list of possibilities.

 

[HawaiiDiver]

I'm interested in whether freeflows are relatively rare enough to be considered a non-issue for *recreational* divers.

It's definitely something worth considering. I'd bet everyone who uses a well-maintained reg and isn't a sloppy diver will find freeflows virtually nonexistent.

 

[DA Aquamaster]

In my pony using days I expereinced only one freeflow. This was due to the water flow caused by a rapid descent down a wall depressing the diaphragm. It was also unfortunately in very cold water (uppper 30's) and the inital freeflow was enought to freeze the first stage. Since the pony was back mounted and the valve lower than the main tank valve, I could not reach it to shut it off (and the buddy was too clueless to figure out what I wanted him to do.) It was a situation where 3 failures combined to cause a loss of the gas in the pony (2 mechanical failures, 1 buddy failure) and as such was predictably a rare occurrence. It was an irritation and I lost one form of redundancy for the rest of the day, but it was not a serious issue as it was not in a soft or hard overhead environment.

And that I think is the point. Rare or not, if losing the gas in your pony in any way presents any kind of serious concern, you need to consider whether you are still within recreational limits and whether a pony is adequately meeting your needs. After my freeflow incident I considered that most of my diving was deep and that an increasing amount was deco and that even a 30 cu ft pony, and in particular a back mounted pony, left me at risk in some situations. Consequently I switched to redundant doubles and eventually used the pony as slung deco bottle.

So if you are strictly a recreational diver, back mount away. However if you are diving outside the recreational limits in any way shape or form, consider slinging a large pony. You also need to consider that the limited gas supply of even a large pony provides only a very small depth/time range extension so you also need to consider if some form of redundant doubles might serve you better.

 

[hecker-the-wrecker]

It's definitely something worth considering. I'd bet everyone who uses a well-maintained reg and isn't a sloppy diver will find freeflows virtually nonexistent.

Very true. Part of a well maintained reg, is the normal use of the reg. I would suggest not keeping the pony tank corked,(shut off) during the dive, we hook up ours to our drysuits. This way the first stage gets used from time to time. This way the status of your pony is known at all times. I just hate to think you would find out there is a problem with your pony after you turn it on,(and really need it!) It's also up for debate, but in my opinion, the air in your pony should be cycled out from time to time. I haven't had a freeflow yet, but im sure it will happen someday, and i'll be prepared.

 

[matt_unique]

How many people here who use a backmounted pony left on during the dive have had the pony reg freeflow, and what were the causes of the freeflow?

I dive with a Sherwood reg on my pony when I dive singles so the air stays on the entire dive. When it was brand new it free flowed because it was tuned too close to crack pressure for the required task. Once that was adjusted - it never free flowed. When I dive a single I back mount with Highland Mills bands, bottle upside down, right side.

I dive cold water (Massachusetts) so the temps get down to the mid 30's in the winter. I have never had one of my Sherwood's freeze.

--Matt

 

[wscdive]

As far as frequency goes, empty ponies from freeflows are not all that common. The reason we stress highly at my shop for slung ponies is that years ago we did have one diver (before I was involved so I only hear the dive shop side) have the free flow problem. Unfortunately he discovered it at depth when his main either failed or was empty. He didn't make it. For my style of teaching and diving this was frequent enough to advocate the change. (I dove for years with a back mounted pony and never experienced a free flow but I always dive with high quality cold water regs on every post, i would imagine free flows would be more common on the typical less expensive pony regs.

 

[TwoTanks]

I dive frequently with a pony. I have in the past used it backmounted and now I usually sling it. Both ways have their pros and cons. To stay on topic, when I backmount the pony I keep the 2nd stage on my chest so would I notice a freeflow and I have never had one underwater. On water entry it is the same as any other reg, ocassionally it will freeflow but I just flip it down. I have used several different regs on my pony including, scubapro, oceanic, seaquest and sherwood. I don't use a high performance reg on my pony. My ponies are 20 and 30 CF so a little air loss from a quickly noticed freeflow would not be a problem anyhow.

Loosing my backup from a pony freeflow is at the bottom of my list of concerns on any given dive. If I was worried I would sling it with the valve off or use doubles.

TT