pony bottle or spare air?

[chirodoc]

What is a pony bottle? I get the spare air thing, but Ive seen it connected to the front of a BC where its easily reached. How is the pony different( I know it ha more air) but is it in back of you like your tank, or can you reach it really easy? I dont get where it goes

[FishFood]

It's just a smaller (Usually... Really you could call anything a pony.) tank with an independant reg setup.
Type "pony bottle" into Google Images and you can see some various ways to attach it to your tank.

pony bottle - Google Image Search

Also, many people "sling" it, or attach it to their harness/BC via a couple clips to the Drings.

[fire diver]

If you want a fully redundant gas supply in case of emergencies, then get a pony and stay the hell away from "spare-death". Spare air is fine if you are within maybe 20' of the surface, but then you could just CESA that with ease. If you going to go below that, and want an adequate volume of gas to get you SAFELY back up to the surface with a normal safety stop (on most profiles) then get at least a 19cf pony.

[ScubaDude]

Originally Posted by fire diver

If you want a fully redundant gas supply in case of emergencies, then get a pony and stay the hell away from "spare-death". Spare air is fine if you are within maybe 20' of the surface, but then you could just CESA that with ease. If you going to go below that, and want an adequate volume of gas to get you SAFELY back up to the surface with a normal safety stop (on most profiles) then get at least a 19cf pony.

Chirodoc, as fire diver said, stay away from "spare-death", it's totally useless, ..... I'd get a 30 at the very least.

Be safe.

[Duckydiver]

I had a spare air. Shortly after I bought it, I sold it.. and bought a 30 cf pony and a used basic reg. All togather it was only a little more for the pony. If your trying to make a choice I wouold advise a pony of any size ( just not 3 cf).

As for "where does the pony go" It can be mounted to your main trank with the reg cliped to your bc. or you can sling it to your bc in the front. Some bc's (like mine) can not accomedate that. So I mount it to my tank.

I hoped that helped.

[emcbride81]

Yeah go with the 30. I got a 19cuft pony and I wish I would have just gotten the larger one. It would be better than a spare air in an emergency, but more air is more air....and more air is better...which you get with the 30.

Maybe I will turn it into a high percent 02 when I get into technical...

[in_cavediver]

Do a search for spair air, spair death etc and you'll get more than you ever wanted.

That said, here is a fairly honest appraisel of the equipment.

--- Observations -------
Before looking at a pony or spair air, look up gas management, rock bottom and understand quantitatively how air is used. IE - Surface consumption rates and how depth changes it. Once you see that, we can talk about Surface rates in cft/min. Mine is around .5cfm/min on average.

Now, lets talk depths. Spair air is rec so lets say our dive is to 100ft or 4 atms of pressure. 130ft is 5atm, 66ft is 3atm and 33ft is 2atm.

Now, this is the biggie. If a diver goes OOA, they will be stressed. When stressed, air consumption goes up 50-150% or 1.5x-2.5x the original. For me, I simply double my surface rate. This lasts between 1 and 2 minutes after getting on additional air before returning to normal. I plan for 2 minutes.

----- planning -------

Assume at 100', within NDL etc and go OOA with spair air. At this depth, my normal air consumption rate is around 2cft/min. By going OOA, I am not at around 4cft/min. With spair air, I cannot stay on the bottom 1 full minute. I need to start ascending immediately. If I go from 100ft to 33ft in 30sec, (average depth of 66ft and holding 120-130ft/min ascent rate) I will use 3cft of air and exhaust the spair air and go OOA again.

Do the same for a dive to 66ft. I go OOA and my consumption rate goes to 3cft/min at depth. My ascent will take 1 min @ 60ft/min and use 2cft. I can stay on the bottom at most 20 seconds to make it to the surface.

Now, using a 19cft pony:

100ft OOA - goto pony and stay at depth 2 minutes getting my buddy etc. I used 8cft of air doing that. I then do a standard ascent to 20ft @ 30ft/min. It should take 2.5 minutes with an average depth of 60ft (about 3atm) In this I used around 4cft. I still have 7cft in my pony to do a safety stop. I burn 0.8cft/min of air at 20ft so I can do 3-4 minutes if I want to. The final ascent should take 0.5 - 1cft of air.

------------ more observations -----------------------
From the above situations, you can clearly see the limitations. Spair air is a CESA aid and nothing more. Depending on the depth, you may go OOA again before reaching the surface.

Comparing that to a pony is simple, all it boils down to is the cft of the tank. A 13cft tank which is a small pony, offers a larger delay time and margin for error for roughly the same cost as spair air (so is the 19).

Now, one thing spair air is really good for is this. Its very small and its likely that you'd carry it and have it to use. A bigger pony is just that, bigger. It's one of those questions of whether you'd really carry it. It does no good on the boat.

----------------- My Biases ------------------

At this point, I am beyond a pony. If I think I need a pony, I am taking true redundant air and if solo, a buddy bottle. (full 1/3rd of my bottom gas or more). If you are doing deep rec dives - IE 70ft or deeper, a pony is a good idea. 70ft is the depth where I personally decide I need redundant gas.

Spair air does have its place but its not with *MOST* scuba divers.

[Navy OnStar]

Originally Posted by in_cavediver

Spare air does have its place but its not with scuba divers.

This place USED to be with military helicopter crews but even we got rid of them due to some peculiar quirks. We now use the HABD system made by U.S. Divers which is very similar to a Zeagle Razor with a smaller tank. We only use them to give us a few breaths incase we crash in the water. Helicopters are top heavy and tend to flip over on impact and sink. They give us enough air to undo the seatbelt ditch the door and ascend to the surface from about 30ft.

[fire diver]

I found a spaire air in the MRAP I was in last month. I wished I had my camera with me at the time. It would be the only time you'd ever see me with one in my hand.

It was there for the same reason as listed above. If the vehicle rolled over into water, a person in the back could use it to find thier way out of the vehicle.

[ScubaToys Larry]

Obviously, I'd much rather sell someone a pony bottle, another reg, gauge, pony attachments, etc - than a spare air. It will cost much more! But that being said - I have taken a 1.7 spare air from 100 feet to the surface. And when I travel - these days, carrying an extra 30 lbs of gear is pretty much impossible - so I do carry a small spare air with me. I'd much rather have a few cubic feet of air with me than 30 cubic feet in my closet. And I know, have tested that it is enough air to get me up to the surface.

In a real emergency, will I breathe harder?? Sure - but I'll probably swim faster too. Will I have enough air to do a deco stop? Probably not - but people recover from the bends... drowning... not so much. Would I rather have 19, or 30, or 40, or 80 or 120 cubic feet of extra air... sure.... but it's not practical for the traveling and diving I do.

Just another take on it...