How deep until you need to bring along a pony bottle?

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

Either independant doubles, or with an iso manifold does provide redundancy. You use two first stages, with a second stage attached to each.

Using twin tanks with a single first stage would be kinda dumb...

Se7en
 
gbrandon once bubbled...
Why would someone look into doubles instead of a pony if they were only using a single tank?

If they want real redundancy and don't mind the added weight, doubles are an option. If they can't handle doubles then there are other solutions, mainly better planning.


Doubles does not give you true redundancy.


Actually, they do. This is if you are talking about doubles with an isolation manifold. You are thinking of independant doubles or doubles without an isolator...yes, those are not fully redundant and most people know better than to buy them.


How are doubles going to fix a 2nd stage failure, or a first stage failure for that matter?

Do a search for how doubles work here on the board. Again, I think you were refering to independant doubles here.

Doubles offer true redundancy but, only if you are willing to use them.
 
ElectricZombie once bubbled...
You are thinking of independant doubles or doubles without an isolator...yes, those are not fully redundant
...independant doubles are fully redundant... and totally... well... independant.

The twinsets that would not be redundant are the manifolds or yoke connectors with only one first stage connection.
 
You would not have access to the gas in both cylinders though...just whichever one had not failed. That's why I said they were not "fully" redundant.
 
I use my pony bottle on all deep dives, 90+ feet, and anytime using my FFM. Others have mentioned using doubles, and, when configured properly would serve the same function. Not everyone can handle the added weight not to mention proper BCD as not all BCD's are designed for use with double tanks. You have to be the judge, if you feel using a pony bottle will add an extra margin of safety, go for it. You can plan and prepare all you want, but I'd rather have it with me and never use it than need it once and not have it.
 
AquaGuy once bubbled...
I was wondering at what depths do you need to bring along a pony bottle? <snip>

My buddy wears my pony bottle on his back. :)

R..
 
There seems to be a few replies in this thread that , how shall I say this??? Sound interesting ;-)

I think the starting point for any true analysis if someone is concerned enough about "issues" at depth that would require an alternative air source, one should consider spending more time practicing and diving in a unified team fashion.. Using "gimmicky" gear to solve unified team deficiencies is tantamount to putting a band aid on a serious wound. It doesn't solve the problem, but it does offer the appearance of a solution..

Secondly, I've seen some rather unique ideas about doubles. Doubles are the recomended option in diving to those depths, and they do in fact offer true independance.. Spending time practicing in the shallow's doing valve drills and becoming comfortable manipulating your valves allow for the same redundancy that we use inside wrecks, caves and so forth.. It seems to me that if a set of doubles provides for satisfactory redundancy inside a cave or a wreck, it would also allow for adequate redundancy at ~100' in the open ocean.. Using "isolated" doubles or "independant" doubles isn't a wise idea either. A proper set of doubles complete with isolator is much simpilier then worrying about "independant" doubles and the requisite gas management protocols associated with independant doubles..

As for your initial question about pony bottles, they are crutches for those that don't want to spend the time to practice diving in team protocols or don't want to spend the time to learn doubles.. I approach a dive that if I "think" I need redundancy then I probably do, so why not assume that you will and approach the problem with effective solutions, rather then ad hoc crutches that may, or may not, be sufficient when the time arrives you need it???

Generally speaking, the Pony bottle thought process doesn't extend far enough to actually solve the problem, but they sure provide the illusion of attention to problem solving ideas..

Hope that helps..

Later
 
is all too common of the GUE "one true way" kool-aid nonsense.

Kane, you know better. You've conveniently ignored the very reasonable (and realistic) scenarios under which some (myself included) have presented the case for a pony, how we rig them, and why.

You claim that the solution is to dive as a "unified team." What you really mean is that we shouldn't spearfish, and absolutely should not spearfish where BOTH divers are persuing the taking of fish at the same time. Nor should we EVER find ourselves buddy-absent. Its very nice for you to pronounce that in an open water environment where buddy separation CAN happen, that we'll simply say "don't do that" and ignore the risk that it both can and does.

Gee, how about if we say "oh no, you can't dive in a cave, because that requires extra care and gear, and well, that's just too damn dangerous. Dive in non-overhead environments only and the problem goes away."

That's offensive, no? So how come what you're saying doesn't carry the same obligation and view?

Doubles are not "difficult" to use or learn, but they do bring MASS to the table, and that mass is inescapable. You've been engaged on this point several times, but you keep ignoring the very real fact that not even GI3 - or you - can repeal the laws of physics, and the most important one in play here is the basic principle of inertia. Rather than address it, you just ignore it.

The mass penalty for a set of doubles is substantial. In a non-overhead environment, but one where you are too deep to make a safe CESA, a pony bottle brings the REQUIRED redundancy to make a safe ascent, while NOT bringing with it extra mass that serves no purpose other than to decrease your efficiency underwater and increase entanglement risk. Never mind that its a royal PITA getting back on a heaving dive boat with a set of doubles on your back, as opposed to the far lower mass of a single.

Now if you NEED the backgas of a set of doubles, then by all means take them.

It amazes some, myself included, that you would garf about someone slinging a bottle for bailout while at the same time you'd sling a bottle for deco. Gee, you COULD decompress on backgas for dives in which that gas would not be hypoxic, no?

Yeah, it would take longer, and you might have to cut your bottom time shorter, but remember, the GUE mantra you're espousing here is that you never take any UNNECESSARY gear. That is, gear taken for convenience, or to address a contingency is improper, right?

So nice your double standard is.
 
Aren't there some situations where doubles are overkill and a pony bottle has it's place? For example, if I'm going to be doing a penetration of a shallow wreck <30' off a small boat and probably only using 40-50cu of air total, why should I lug along doubles instead of an AL80 or a steel 100 w/ a 40cu pony?

Isn't diving with a pony slung good practice for future stage compression?
 
https://www.shearwater.com/products/teric/

Back
Top Bottom