Do I need a pony?

[rongoodman]

I think it makes sense to carry a pony if you can get it filled with 50%. .

Other issues aside, where is a diver with less than 24 dives going to get 50%?

 

[Zef]

I think it makes sense to carry a pony if you can get it filled with 50%. You can use it down to 20 meters, and then you can switch to it on your safety stop to give yourself some extra decompression security, and you therefore also use it regularly to make sure it’s all in working order.

I can't stress enough how bad a recommendation this is in the context of the OP's discussion post.

What you are suggesting is not a redundant gas source but instead a stage bottle. The OP is asking about carrying a small cylinder as a redundant air source....one he can switch to regardless of depth (within recreation depth limits) should he have a problem with his primary cylinder or regulator set. With 50% O2, that would be an issue below 18 meters if using a PPO2 of 1.4 as recommended for diving Nitrox. Plus, if I am not mistaken, all the recreation level Nitrox courses certify blends only up to 40%...Without advanced Nitrox training the OP would probably not be able to get a 50% O2 blend fill at a dive shop.

OP,
I carry a 200bar 3L pony (@ 21ftcu, slung under my left arm). I carry it almost every time I dive as insurance because as a divemaster the skillset and experience of some of the folks I dive with is either unknown or questionable, and I do not want to find out IF I can rely on them (or not) when things go awry. I don't think I would take it with me when I travel as I would be diving with my wife or one of my 2 kids (both adults), and I have confidence that I could rely on them if something went wrong (both my daughters are rescue certified and my wife is planning on becoming rescue certified in September/October if the pools here open back up).

Just a note, I carry a pony bottle as an alternative to diving doubles as I have some upper back issues and the added weight of a doubles setup would cause me lots of discomfort on the way to/from the water. For me, the pony bottle is a good compromise.

I also agree with the poster above who said that you (OP) should dive some more to gain experience to help guide your decision.

-Z

 

[halocline]

It's always good to hear both sides of the pony argument:

 

[James79]

I have a 19cf, and use it about 50% of the time. I dive with my kids (10 and 14), and like knowing that I can focus on being there for them, and don't NEED them to be there for me. Also, as @lowviz said... It's handy for quick stuff in the pool. I also DIY, so it becomes the easy air supply for working on gear in the house. Lastly, some shops want to charge for a vis if the tank is truly empty when you bring it for a fill, and travel by air will require you to pull the valve. This thread; Tank Equalizer for $2.50 tells how to do a cheap tranfill whip so you can either just fill it yourself off your main tank, or transfer a couple hundred psi to it so it's not "empty" when you go to get it filled.
Respectfully,
James

 

[drk5036]

his profile says he has 0-24 dives and you have him using 50% and doing deco?

I didn’t have him doing deco, or at least it wasn’t my intention. My point is, for literally everyone, using 50% at your safety stop would be beneficial compared to using air, no? And especially if he wasn’t going deeper than 18 meters, technically there would be no problem with using 50%.

if I walk it back to, why not fill it with 40% nitrox, that he easily could get filled, would that make people feel better, or still not a good idea? I think it’s not uncommon to get a pony filled with nitrox, especially if your dive profiles never take you below ~30 meters...

 

[JakeP]

thanks for all the reply's...I have right at 20 dives so far. AOW and Nitrox. I think this is something that I will end up with eventually, but will probably hold off on right now. Im a few years from having my girls diving with me....once that happens I will absolutely carry one.

 

[johndiver999]

I didn’t have him doing deco, or at least it wasn’t my intention. My point is, for literally everyone, using 50% at your safety stop would be beneficial compared to using air, no? And especially if he wasn’t going deeper than 18 meters, technically there would be no problem with using 50%.

if I walk it back to, why not fill it with 40% nitrox, that he easily could get filled, would that make people feel better, or still not a good idea? I think it’s not uncommon to get a pony filled with nitrox, especially if your dive profiles never take you below ~30 meters...

I think it is not a good suggestion.
Why assume he wants to pay the money to get the bottle filled every trip?
Why assume he will have enough volume for a second or third dive (and a true emergency) if he uses it on early dives?
Why assume he will never dive where it is deeper than 70 feet?
Why assume another diver might not grab that regulator at depth?
Why assume the diver has training for nitrox?
Why assume there is an actual benefit of doing an optional safety stop with a different gas?
Why assume the diver wants to check the gas mix in the pony bottle each time?
Why assume the mix will always be correct in the pony?
Why assume the diver would spend money to put nitrox in the pony but not in his main tank where it would actually provide a discernible benefit in terms of extended Nodeco dive time?

All these assumptions, costs, complications and potential problems when the expected benefit is negligible at best?

I bet somebody could do a computer simulation and determine that an extra 60 seconds of safety stop on air would have the same relative (off gassing) benefit of 50% at 20 feet.

 

[RyanT]

if I walk it back to, why not fill it with 40% nitrox, that he easily could get filled, would that make people feel better, or still not a good idea?

Yep, still a bad idea for a variety of reasons. If a recreational diver is carrying a pony for redundancy, it should be filled with the same mix as the diver's back gas. A whole lot of things can go wrong when making the switch to a different gas and this is why tech training exists.

 

[GJC]

thanks for all the reply's...I have right at 20 dives so far. AOW and Nitrox. I think this is something that I will end up with eventually, but will probably hold off on right now. Im a few years from having my girls diving with me....once that happens I will absolutely carry one.

Take a Rescue course before you start diving with your girls.

Consider taking a Solo course after you have 100 dives. Even if you never plan to dive solo, the skills you learn will make you a better diver and give you the ihformation and skills to dive with a pony.

 

[Divin'Papaw]

50%???? Why would your pony ever need to have anything except air? If it has 50% it's a deco bottle not a pony bottle and should only be used by those trained in deco procedures. Switching to your "pony bottle" at your safety stop because it has 50% is using it as a deco bottle. Not a good idea unless you are properly trained and experienced.

I use nitrox exclusively in my back gas tanks. Typically 36% for the dives that I typically do. But my pony bottles always have nothing but air. That way I know that regardless of where I am during a dive my pony has breathable gas. No need to worry about MOD. The need for nitrox is nonexistent if you need to switch to your pony. At that point the dive is over and you're head back to the surface. A pony is intended to be an emergency redundant gas source. Period.

I also use my pony bottles to fill tires, as a blower on occasion, for soaking regs, etc. Nitrox is either a bad idea for those uses or at least a silly waste of money. Another reason why my two pony bottles (both AL40s) never see anything but air.