Do you actually see people diving with pony bottles?

[2airishuman]

Guidance directed at whom? I'm not familiar with the Solo or Self-Reliant courses, but I would expect them to teach how to use a pony. If one has to rely on insta-buddies or that sort of thing, then by all means take a Solo course and learn how to use a pony. So, if you meant that the guidance/training in Solo courses on the use of ponies is inadequate, then I agree they should address that.

There are many people who do not dive solo but who use a pony cylinder for other reasons, such as:

• On a deep, coldwater dive, a pony cylinder is useful for dealing with freeflow due to freezup.
• Used properly, a pony dive can improve safety on buddy dives. Buddy separation is a factor in many accidents, and is not a problem unique to "insta-buddies." There are also accidents where both divers in a buddy pair end up OOA.
• With careful gas planning, a pony cylinder can be used to extend the duration of a dive, either by reducing the reserves required in the primary cylinder, or by intentional planned use of the gas in the pony cylinder at some point in the dive.

Pony cylinders are mentioned in the Deep Dive portion of the PADI AOW course but there isn't much if any guidance on how to use them. I don't know whether they are addressed as part of the Deep Diver specialty. There are many people who use pony cylinders who don't have any substantive training beyond AOW. I would think that is where it belongs.

The rest of your post makes me realize why many people consider diving with two tanks to be bordering on the tech realm. Perhaps diving with a pony doesn't present potential issues that are all that different from those involved in backmount doubles or sidemount? As I alluded to above, maybe some of the people who are diving with ponies are, in effect, just using them as a way to avoid the hassle (and cost, training time, etc.) of backmount doubles or sidemount. Maybe it's dangerous for one to think of a pony as sort of intermediate ground between a single tank and doubles/sidemount--"doubles light," if you will.

I sometimes dive doubles, and sometimes dive a pony. I dive solo but am not a technical diver and do not dive beyond recreational limits.

Doubles and pony cylinders are tools for different jobs, although there is some overlap.

The great thing about a well-chosen pony rig is that it has minimal impact on topside operations, so you get air and get to and from the dive site the same way you would with a single cylinder. There's a little more to carry but not much. There is also minimal impact on your gear -- you can use your choice of exposure protection and BC, with just minor tweaks to weights.

With a twinset you have to have one since they are difficult to rent. Better still to have more than one, but they're expensive. You have to get the twinset(s) to and from the dive site and they are a lot to handle. With a charter or liveaboard you need their cooperation, and many don't permit them. You need a BP&W or one of the few jacket BCs that will work with a twinset, and you have to think more carefully about buoyancy failures. Many if not most divers will have to make substantial trim changes to compensate for a tendency towards floaty feet, something many tech divers address through choice of fins.

Either way you have to know what you're doing.

 

[Dan]

Sometimes you have a lifetime opportunity that you want to take it right there and then to do a dip dive. I saw this big guy being cleaned by a couple Emperor Anglefish at 150 ft (46 m) deep. I was already at 130 ft (40 m) but still have a few minutes of bottom time. The water was calm with 100 ft visibility. I looked back to my guide. He knodded & waved me to get closer to the big guy. So, I went down to 144 ft (44 m) to get a better look & snapped that shot. This was done on a single AL80.

 

[MXGratefulDiver]

There are also accidents where both divers in a buddy pair end up OOA.

... more common than some people think. I always used to put this thought to my students when discussing OOA situations ...

"If you reach a point where you have to turn to your buddy and slash your hand across your throat because your tank is empty, how much air do you think it's likely your buddy's going to have to share?"

This is also a powerful argument for carrying a pony ...

... Bob (Grateful Diver)

 

[MXGratefulDiver]

Sometimes you have a lifetime opportunity that you want to take it right there and then to do a dip dive. I saw this big guy being cleaned by a couple Emperor Anglefish at 150 ft (46 m) deep. I was already at 130 ft (40 m) but still have a few minutes of bottom time. The water was calm with 100 ft visibility. I looked back to my guide, he knodded & waved me to get closer to the big guy. So, I went down to 144 ft (44 m) to get a better look & snap that shot. This was done on a single AL80.

View attachment 430387

... which is fine as long as nothing goes wrong. But suppose you were down there at 144 feet and halfway through your inhale your cylinder suddenly stopped delivering air.

What would you have done?

... Bob (Grateful Diver)

 

[MaxBottomtime]

I've advocated on here divers should be self sufficient. Redundant gas source eliminates a diver relying on someone else carrying his emergency gas. Considering buddy separation is one of the leading initial causes of diving fatalities, divers need to learn how to dive on their own. Even if they have a buddy.

I agree with everything except the buddy separation. Your gear and gas supply on your back remains the same whether you're near another diver or diving solo. Not paying attention to your spg and panic is the leading initial cause of diving fatalities. Following the skills you were taught in your OW class will keep you alive.

 

[MaxBottomtime]

If you reach a point where you have to turn to your buddy and slash your hand across your throat because your tank is empty, how much air do you think it's likely your buddy's going to have to share?"

This is also a powerful argument for carrying a pony ...

... Bob (Grateful Diver)

I believe it's an even more powerful argument for watching your spg. A buddy team running low/OOA should never happen. I guess I've been fortunate to have never been in a situation solo or with a buddy when a pony would have come in handy.

 

[Dan]

... which is fine as long as nothing goes wrong. But suppose you were down there at 144 feet and halfway through your inhale your cylinder suddenly stopped delivering air.

What would you have done?

... Bob (Grateful Diver)

I still had about 1000 psig at the time (my SAC is 0.4 cfm). My dive buddy / guide / DM, was right behind me in about 5 ft away. If my primary reg were to stop delivering gas, I would pull my octo off my BCD chest D-ring & started using it. If that failed, then I would go to my redundant air source, i.e., my guide octo. I have him as my guide in Bali for the last 10 years. We discussed this scenario many times, but had never been actually using it. I have never been in OOA, ever, in 12 years, 600 dives any way & not planning to (knock on wood).

 

[Storker]

I need enough of a safety margin to get me and my buddy to the surface in a controlled manner from any point in the dive, a volume sometimes referred to as "rock bottom" or "minimum gas." For me, that means a bigger single tank or double tanks for anything more than a bounce dive to 130 ft. A pony seems like a reasonable option, too, but I have simply chosen not to go the pony route.

Another very good reason - besides my propensity to become narked - for my personal depth limit of approximately 30m/100'

 

[Storker]

On a deep, coldwater dive, a pony cylinder is useful for dealing with freeflow due to freezup.

How common are 1st stage freezeups for environmentally sealed (i.e. membrane) 1sts? In my neck of the woods, piston 1sts are about as common as hen's teeth, and so are 1st stage freeflows.

OTOH, 2nd stage freeflows after surfacing are more or less SOP when the water's cold and the air is below freezing. But those are just a minor annoyance.

 

[Dan]

Pony bottle usages in warm-water diving are out there, but not too common, as many posters here have pointed out. Even some liveaboards carry & offer solo diving class for carrying the pony bottle. For example, I was offered by Spoilsport cruise director Liveaboard Scuba Diving Australia - Great Barrier Reef, Osprey Reef, Cairns, Australia. while heading to Code Hole, to take a solo diving course so I can use one of their pony bottles, but I didn't take the offer. It is another unecessary gear that I have to worry about in warm-water recreational diving.