Pony bottle for BC & Octopus?

[scubabunny]

Originally posted by Rick Murchison

Using a pony as described and having an Air2 as well crosses the line of unnecessary complexity. You need *one* safe second. If you want to carry a bailout bottle by all means do so, but don't hook it to an Air2. To get redundant first stages and use an Air2 you should use either an "H" valve or doubles - something you don't intend to hand off.
If you're using a pony as a deco bottle, or carrying it acting as a safety diver then it isn't your safe second.
Rick

Rick, I wasn't suggesting that a pony bottle hooked up to an Air2 is a good idea. But, I don't see anything wrong with a rec diver carrying a pony bottle. Better to have a pony bottle than have to shorten your safety or deco stop because your tank is out of air. And, if something happens to the first stage...both the primary and Air2 are worthless (not likely at depth...but always a chance).

I know the H-valve or doubles solve that problem, but isn't that considered "tech diving" by most agencies, and therefore have a dive number requirement? I only know PADI and TDI..and they both require a minimum number of dives before that is introduced. Doesn't really help a new diver.

 

[Rick Murchison]

Originally posted by scubabunny


Rick, I wasn't suggesting that a pony bottle hooked up to an Air2 is a good idea.
Good.
But, I don't see anything wrong with a rec diver carrying a pony bottle.
Nor do I - with your alternate hooked to your Air2, your pony is a bailout bottle.
Better to have a pony bottle than have to shorten your safety or deco stop because your tank is out of air.
Why would your tank be out of air? Why would you be making a deco stop?
And, if something happens to the first stage...both the primary and Air2 are worthless (not likely at depth...but always a chance).
True - but we *are* talking open water, right? And we *are* talking remaining within the NDL limits, right? And you *are* diving with a buddy, right? So you have the options of an emergency swimming ascent or air sharing with your buddy, right?
I know the H-valve or doubles solve that problem, but isn't that considered "tech diving" by most agencies, and therefore have a dive number requirement?
Not "tech diving" at all. More robust equipment configurations are required for "tech" diving than for what we usually call "recreational" diving, but the use of that equipment doesn't make the dive a "tech" dive. An open water dive within recreational depth limits and within the NDL and within the conditions for which you were trained as an open water diver is a recreational, not a "tech" dive, regardless of the equipment you use. There is nothing magic about using an "H" valve, and 10 minutes in a pool practicing valve manipulation will get you comfortable with it. Doubles might take 20 minutes.
I only know PADI and TDI..and they both require a minimum number of dives before that is introduced. Doesn't really help a new diver. Any PADI or TDI instructors know anything about these requirements?

I'm not telling you not to carry a pony bottle. I *am* asking you to consider why you want to carry one, and to think of more planning and action solutions to potential diving problems before throwing equipment at 'em.
Rick

 

[92630Diver]

In case anyone else investigates this thread... between the time that I posted the initial message and now I have read about a system that is designed to function in a configuration similar to that which I'd asked about. The Aquavit X-tra self rescue system supplies air for both the octopus and BCD, or in my case could be connected to the Seaquest Air Source or Scubapro Air 2.

If anyone is using this system I would like to hear their opinion of it. I'd been considering the purchase of a Spare Air system, but now I'm leaning more toward the Aquavit X-tra 100.

 

[Scubaroo]

92630Diver,

Please reconsider getting a pony bottle at all. Do a search on "Spare Air" on this website and find a dozen threads on why they're a bad idea.

First, your BC. You remove air from your BC to ascend - adding air to initiate ascent is a bad bad idea, as you suddenly find yourself in an uncontrolled ascent because the air in your BC is expanding and your bouyancy is rapidly increasing. Your BC is not an elevator to the surface. To ascend correctly, you should be able to initiate ascent with kicking, while removing air from your BC in order to maintain neutral bouyancy.

If your BC inflator malfunctions at depth, and you can't add air to your BC, you should be ascending as described, and have no further need to add air to your BC until you surface, where you do it orally. Adding air at depth to your BC implies you are going deeper and need to compensate to maintain neutral bouyancy. That eliminates the argument for a redundant air supply for your BC.

Second, redundant air for yourself. Are you diving solo? I hope not, as back in February you indicated you were new to scuba. I've been diving regularly for a year, and still won't consider solo diving. So you should have a buddy with you on the dive. Your buddy is your backup air. Buddy diving is diving as a team, not same-ocean diving. Your buddy should always be close enough that you can reach them if you require use of their backup regulator, and you should always be aware of each other's air supply situation, to reduce the chance of running out of air in the first place. ANY situation requiring an airshare is a situation where the dive is terminated and you should be heading for the surface. Either you've run out of air, or have had a regulator failure. The dive is over.

If you want to use an Air2 for streamlining, adding a bailout bottle immediately increases your drag (and taskloading), more than negating the small gain from eliminating a 30" octopus hose. So buddy diving and increased drag eliminate the argument for a redundant air supply that isn't your buddy.

I realise that this is a bit strongly worded, but hopefully you'll pick up on the point roakey was making, never introduce a "solution" that's more complex than the original problem. Consider the complexity you're introducing to a task as simple as changing cylinders with the X-tra system.

Ben

 

[92630Diver]

Thanks for your opinion. I have searched on "Spare Air", "Pony Bottle", etc. I even went so far as to read each and every posting and opinion on the subject. I have not made a final decision one way or another.

It is apparent that a few of you fail to grasp the actual purpose of the configuration that I had originally sought input on. The pony bottle in this scenario does not serve the sole role of emergency air supply. Instead it would server a dual role. My intent was to ask whether an appropriate capacity pony bottle could also provide buoyancy control on the bottom (not to be confused with the assumption that I intend to use it to add air to my BC in an emergency ascent). This would merely be for adding small amounts of air to the BC while on the bottom for buoyancy trim. My theory being that very little air is actually used to obtain buoyancy while diving once one has mastered the technique. This would then leave ample reserves within the pony bottle for an emergency situation. If such a situation does not occur, then at the end of the dive the air within the pony bottle could be used as needed to fill the BCD for surface stability. Otherwise the BCD would be inflated manually.

Someone out there has actually thought of such a configuration... as evidenced by the invention of equipment such as the Aquavit X-tra. Ultimately I'll make the decision that is right for me and stick to it. Worst case scenario I'll have extra gear sitting unused in storage one day.

The refresher course on proper BCD use wasn't necessary. I don't think that even a strong blow to the head would cause me to confuse a BCD with an elevator to the surface. I'd have had to both sleep through the OW instruction and skip over pertinent sections of the PADI Instruction manual entirely in order to confuse that issue. I'm sure you meant well though.

 

[Scubaroo]

Hi 92630Diver,

Take another look at what you're trying to achieve. If the purpose of the pony is two-fold (BC trim and bailout), why not reduce it to just being a bailout bottle. People that do use pony bottles as an emergency air supply often like to be able to hand them off to their dive buddy. Attaching it to your BC will severely hamper this.

Originally posted by 92630Diver
This would merely be for adding small amounts of air to the BC while on the bottom for buoyancy trim. My theory being that very little air is actually used to obtain buoyancy while diving once one has mastered the technique.

If trimming your BC is going to use so little air, why not use your back gas supply? If you feel that minimal air is required to maintain neutral bouyancy at depth, then keep things simple and just attach your LP hose to the first stage on your back. This will leave your pony bottle free to be carried as a sling bottle under your left arm, and you have the freedom to pass it to a buddy, or leave it behind for dives you don't want to carry it on. And using your pony bottle constantly for BC inflation will eventually deplete the bottle, requiring you to pay for unnecessary fills.

Originally posted by 92630Diver
The refresher course on proper BCD use wasn't necessary.

Good - believe me, thousands of divers could use it.

cheers

Ben

 

[Uncle Pug]

Originally posted by 92630Diver
Ultimately I'll make the decision that is right for me and stick to it. Worst case scenario I'll have extra gear sitting unused in storage one day.

Well... no... that is not the worst case scenario...

Just exactly what issues are you dealing with here... what perceived problems are you trying to solve?