Do you actually see people diving with pony bottles?

[2airishuman]

I would like to point out that you can also do that with independent backmount doubles. Same kit as for a manifolded twinset except you add a second SPG, and you need a backplate that has camband slots for doubles, or an adapter.

 

[lermontov]

Well, I guess the bottom line is that I am skeptical of things that are "simpler" being "better." As I alluded to, I have to wonder if carrying a pony leads to complacency precisely because there are NOT so many established procedures as there are for sidemount. (As for the procedures "evolving," why not pick ONE and stick with it? That sidemount is in a state of flux is one reason I plan to stick with backmount for the foreseeable future, but that's another story.) You just carry the pony until if and when there is an event that you perceive as an emergency, when with sidemount you could be so much more ready to deal with such an event that it would hardly be an "emergency." (As the tec divers say, the only true emergency is having nothing to breathe.) In other words, it seems to me that if tec/cave divers rely on sidemount to deal with what a rec diver would call an emergency, then it is surely a well thought-out system that would work just as well as it does for tec divers to deal with a rec diver's demand for "emergency" redundancy. Yes, I mean it could be considered overkill--I like that.

The left and right-hand valves are something I hadn't thought of. So rental Al 80s would NOT be ideal for sidemount. There goes that.

you have a good point if your not used to sidemount configuration then carrying a pony may (?)be a procedure that one is not totally familiar with in regard to dealing with an emergency. A competant sidemount diver is more in tune with that configuration and would hope they are less task loaded when it comes to accessing the carried pony.
In regard to the evolving part its is still developing but id say its 80-90% there and the rest is fine tuning, so were only taking about very small differences in development, not a game changer if your considering it.
mirrored valves are the ideal but as @boulderjohn once again if your comfortable with your set ups its not a major

a redundant gas/set up is a wonderful thing and I wouldn't go back

 

[lermontov]

I would like to point out that you can also do that with independent backmount doubles. Same kit as for a manifolded twinset except you add a second SPG, and you need a backplate that has camband slots for doubles, or an adapter.

i can bolt a set of twins straight on to my nomad Xt no problem and no back plate

 

[Coztick]

While sm does force reg. swaps, and makes bailout a non issue, there is no reason this can't be practiced by bm divers with their primary and alternate.
Everyone should be comfortable loosing a reg. for a few seconds...

 

[ljpm]

So it seems to me that if multiple tanks is your answer to the rec dive redundancy issue, and you're traveling by air and want the convenience of renting tanks, then sidemount is your answer.

Sidemounting the ubiquitous Al 80 seems almost as convenient to me as a pony if you're already looking at a 40cf pony. For all I know, it's actually easier in the water than having a slung pony.

I am in the camp that uses my buddy for redundancy rather than a pony, but if I were to instead decide that my redundancy will come from having two tanks, I'm certain I would be a sidemounter and use sidemount on every dive, whether at home or in a distant location, so long as the dive op doesn't object. Indeed, if all of us demanded sidemount for redundancy, dive ops would be forced to cater to it. If redundancy on a rec dive is as critical as we say it is, then maybe the standard configuration that should be taught in OW by all the agencies should be sidemount?

But back to today's reality--and this goes back the nagging question I had when I last participated in this thread pages ago: If you feel you a need for two tanks, then why not face up to the fact and just consistently dive two identical tanks in a conventional sidemount (or backmount) configuration, using the well-established procedures that go along with those configurations, rather than trying to couch the other tank as a "pony"? (The mention in a previous post of an 80cf "pony" is what caught my attention and prompted me to chime in again.) I am in the camp that values consistency and proven procedures, though I noted the comments upthread about consistency, muscle memory, etc. Sidemounting would address all that.

You provide some good points; (not so silent but)

I was told some vacations dive locations (Caribbean) do not understand sidemount and wont allow it. Kinda like not allowing a stage tank for extra air.
Sidemount is not taught in OW. Not complaining here just pointing out that as a new diver I have just learned back mount, and bought all the equipment. Yes I want to learn sidemount but at $2000 for new regs, $1000 for new BC (I have slings for both 40's and 80's) plus the cost of the course it is not a priority. Plus I only travel once every couple years. Slinging an 80 is a minor inconvenience. I'm 6'5" so an 80 isn't really that big on me.
I dive 133's at home which is sufficient. I plan on getting a pony tank but for use as a pony (redundant air). The main reason, I dive with my 12 yo son and 16 yo daughter. An extra backup air source is added piece of mind. Also, in this case a pony is a better choice than twins or even a larger tank. I can pass the pony easily to my son or daughter if they are in trouble. Plus, my daughter always wanted a pony.

 

[Dan]

.... Plus, my daughter always wanted a pony.

LOL

 

[Lorenzoid]

. . . The main reason, I dive with my 12 yo son and 16 yo daughter. An extra backup air source is added piece of mind. Also, in this case a pony is a better choice than twins or even a larger tank. I can pass the pony easily to my son or daughter if they are in trouble.

Just make sure you and your son/daughter practice it together regularly, until all of you can do it fluidly, calmly, etc. If one is going to carry an extra air source because they believe two-tank redundancy is that important, then I believe the second tank deserves the essentially same degree of attention they give their primary tank. To me, that's it in a nutshell, regardless of whether the two tanks are on one's back, by one's side, or one on the back and the other somewhere else.

 

[2airishuman]

The main reason, I dive with my 12 yo son and 16 yo daughter. An extra backup air source is added piece of mind. Also, in this case a pony is a better choice than twins or even a larger tank. I can pass the pony easily to my son or daughter if they are in trouble.

Passing a cylinder is an advanced skill, and there is always some risk of dropping the cylinder.

I dive with my kids (now 14 and 18), and stick to primary donate.

 

[Dan]

Passing a cylinder is an advanced skill, and there is always some risk of dropping the cylinder.

I dive with my kids (now 14 and 18), and stick to primary donate.

Or change each other buoyancy during the hand over.

 

[Diving Dubai]

Passing a cylinder is an advanced skill, and there is always some risk of dropping the cylinder.

I dive with my kids (now 14 and 18), and stick to primary donate.

Oh come on know. Advanced skill. Really. If your carrying a pony, most people will have to clip and unclip to attach it to their kit, or board a boat. Unclipping a pony in not ardious, less so than say deploying a long hose

Or change each other buoyancy during the hand over.

Again another false statement, how negative do you think a pony actually is? An 80 for sure will be a bit negative when full, bur easily compensated by breathing