Pony bottle

[wedivebc]

Look at my profile picture. I have a 30 slung under my left arm. I hardly notice it is there

 

[hex92]

As someone who has used both a back mounting and sling mounting of a pony I would have to say slinging it is easier. When the pony is mounted on your tank you have to switch over the pony when you switch tanks between dives. I found that to be a PITA. I used a catalina 30 and it would throw of my balance...which you could compensate for with an extra 2 lb weight on the other side.

With a slung pony it just doesn't seem to be in the way at all. When I get back to the boat the dive mate will unclip it for me so I don't even have to carry it back to my seat.

I dove with a back mounted pony for three years. I switched to slinging it this year. I sold the mount on ebay. I ain't never goin back

 

[Daryl Morse]

A pony bottle should be a backup incase you inadvertantly run out of air. They are NOT used to extend dive time.

If you're referring to a small bottle such as 13-19 cf, then I would agree that the main, if not only, purpose is bailout. If you're referring to a larger bottle such 30-40 cf, then why carry them unless you intend to use them?

I sometimes dive with a 40 cf sling bottle. I got introduced to diving with a sling bottle when I took the ANDI CSU course. I like a sling bottle for several reasons. I'm not ready to start diving doubles, but a sling bottle provides redundancy for deeper dives. Additionally, I can use it with a richer nitrox mix for "accelerated deco" at the end of a multi-level dive, or with bottom mix to extend a dive with a square profile.

I know there are people who will disagree, but in my opinion, just like there isn't a "one-size-fits-all" pony bottle, there isn't a "one-way-fits-all" for utilizing a pony bottle in diving. What you chose to do with a pony bottle is a function of the size of the bottle and the type of diving you do.

 

[DA Aquamaster]

It's controversial as it violates the unwritten rule that you never plan to use the pony during the dive or figure the gas into the gas plan. But my thoughts are along the same lines that if you have it along, put it too good use with as hot a nitrox mix as the depth will allow and then use it to extend your DCS safety margin a bit by doing your ascent and safety stop on the hotter mix. This would allow you to use 40% in the pony even for 100 ft dives and still keep you at a 1.6 PPO2.

I think where some people also get offended by this approach is that it begins to blur the line between rec diving where doing the entire dive on a single gas is the norm and tech diving where doing the dive with backgas and one or more deco gases is the norm.

 

[wedivebc]

I think where some people also get offended by this approach is that it begins to blur the line between rec diving where doing the entire dive on a single gas is the norm and tech diving where doing the dive with backgas and one or more deco gases is the norm.

Not sure a line needs to be defined here. ALso some people are taught that for bailout purposes a po2 of 2.0 is acceptable and so in your example a 50% mix as a bailout from 100ft would be OK

 

[Daryl Morse]

It's controversial as it violates the unwritten rule that you never plan to use the pony during the dive or figure the gas into the gas plan.

Agreed, that's why I made a distinction between a bailout bottle and something larger.

But my thoughts are along the same lines that if you have it along, put it too good use with as hot a nitrox mix as the depth will allow and then use it to extend your DCS safety margin a bit by doing your ascent and safety stop on the hotter mix. This would allow you to use 40% in the pony even for 100 ft dives and still keep you at a 1.6 PPO2.

Exactly, although I don't necessarily plan to push to 1.6 PPO2 until I start doing mandatory deco.

I think where some people also get offended by this approach is that it begins to blur the line between rec diving where doing the entire dive on a single gas is the norm and tech diving where doing the dive with backgas and one or more deco gases is the norm.

Agreed, this approaches the line, but I don't consider it over the line. I consider the line to be deco or no deco. Sure you can argue "what's the point", but I don't consider this to be that different than doing no deco diving with doubles. It's using a tech tool for rec diving. By the time I start doing deco diving, I'll already be familiar with a sling bottle and gas switching, having used them for no deco diving. I'll start diving doubles before I take a deco procedures course as well, but that's some time in the future.

 

[Tom Winters]

If it works for you, then it's the right size. You find ourself on your pony at 50' and you seem to be out of air, then you need a 40.