Pony bottle question

[Nemrod]

Yes, indeed, people have valid opinions of their own experiance DocMike. And my opinion based on my experiance is that the aux bottle should be sized propotionally to the primary cylinder size and dive profile plan rather than a blanket one size fits all, 40s straight across.

On the ocassion I have taken an aux bottle aboard an aircraft I removed the valve. Installed valve at the destination and filled the tank. I am going to make an ultralight fill whip using the new braided HP hose and then can fill and top myself. I have already begun on it, waiting on swages. It will be three feet long and will not have valves or a guage to minimize weight and size.

On several occadions I have bought a tank and even left it. The cost is amotorized into the trip expense.

N

 

[tkaelin]

I am comfortable with a 6 cuft pony diving relatively shallow (less than 60 ft or so) well within recreational limits not even close to deco limits.

 

[halocline]

The unfortunate truth is that nobody can say that using a pony of any size presents any additional safety until there are studies done that compare identical diving habits with and without pony bottles. Personally I think they are 'feel good' devices that many divers use to justify riskier dive behavior, like diving solo, or pushing recreational limits such that a diver no longer has immediate access to the surface. I'm sure nobody on this thread would admit to doing that, and I'm not accusing anyone directly....

Once you start down the argument of "I need more gas to be safer" it brings up real questions about other elements of dive behavior, such as why you don't have a trusted buddy as your back up, why you are not simply bringing the requisite amount of back gas for a specific dive plan, and why you don't have immediate access to the surface. These are all questions that push the grey area between technical and recreational diving.

The bigger and more pertinent question is "how safe are my dive practices" and trying to increase safety simply by carrying a bailout bottle is probably not the best way to answer that question.

There are lots of risks associated with more aggressive or solo diving, like sickness, accidentally ingesting water, getting lost, entanglement, fatigue, etc....that a pony bottle will do nothing to address. Lots of divers are found dead with air in their tanks.

I do have a pony (13cft) and have used it once in several years. But it's very handy for filling tires and working on regulators, so I keep it around.

 

[JohnN]

I am going to make an ultralight fill whip using the new braided HP hose and then can fill and top myself. I have already begun on it, waiting on swages. It will be three feet long and will not have valves or a guage to minimize weight and size.

Would you please share what you've done for your DIY transfill whip?

 

[doctormike]

The unfortunate truth is that nobody can say that using a pony of any size presents any additional safety until there are studies done that compare identical diving habits with and without pony bottles. Personally I think they are 'feel good' devices that many divers use to justify riskier dive behavior, like diving solo, or pushing recreational limits such that a diver no longer has immediate access to the surface. I'm sure nobody on this thread would admit to doing that, and I'm not accusing anyone directly....

Once you start down the argument of "I need more gas to be safer" it brings up real questions about other elements of dive behavior, such as why you don't have a trusted buddy as your back up, why you are not simply bringing the requisite amount of back gas for a specific dive plan, and why you don't have immediate access to the surface. These are all questions that push the grey area between technical and recreational diving.

This is a good point, and one that is often lost in the recreational pony question. By definition, we are talking about divers with no deco obligation and direct access to the surface. A pony is ONLY there in case of equipment failure on your primary gas source resulting in catastrophic gas loss. And yes, for people who go OOG for other reasons, but that should never happen, right?

The one thing that I will say in response is that a pony may lessen your DCS risk by avoiding the need for a skipped safety stop or even a CESA if you are completely OOG. Again, very hard to prove that given the low (but non-zero) incidence of DCS for divers within NDLs.

Also, low vis divers should be considered solo divers for redundancy planning purposes.

 

[Nemrod]

Would you please share what you've done for your DIY transfill whip?

Yes I will. One issue, being a life long tinkerer and having built an airplane and my Jeep and inbetween and before lots of weird things I have tons of little bits and pieces left over and recycled to make things from. For a DIY project I will need to spec out sources other than my stash of junk. I cut ends off hoses, plugs from cords, you get the picture, I hoard odds and ends much to the dismay of my wife.

I also have lath and mill capabilities though at the moment neither work very well. I am looking to upgrade or make better friends with better equipment.

N

 

[uncfnp]

Would you please share what you've done for your DIY transfill whip?

Don't know if you have seen this but here is what I use...

http://www.scubaboard.com/forums/do-it-yourself-diy/354001-tank-equalizer-2-50-a.html

Already had all the parts except the adaptors from Grainger.

(Sorry for butting in Nemrod)

 

[whitefang21]

Going back to the OP question, proper training is needed when seeking to do solo dives and dives deeper than 100ft. In those classes you should cover proper gas management. After the class you should gain the knowledge and skills to conduct the dives safely. The answer to your questions will be revealed

FYI -the original post mentioned dives deeper than 100ft

 

[redacted]

Would you please share what you've done for your DIY transfill whip?

I used a couple Spare Air fill attachments that I had laying around and had a hydraulic shop fabricate the connecting hose for me ($30).

 

[Basking Ridge Diver]

So forgive me - when or why would you need a transfill whip?

I have bought a whip for myself to fill from a cascade system that is used for different purposes. But I fill my tanks and go dive. When would you need to transfer from one tank to another? I am very curious...
Thanks