using a pony to extend bottom time

[The Mushroom King]

I've already posed this question in the basic forum for the non-dir answer, and now I'm looking for some DIR points of view.

Due to logistics in my area I rely mostly on public transportation and this makes owning my own tanks impractical. Most of the local dive ops have only 10 litre tanks available to rent. These are small and I burn though the gas pretty quick. When I am lucky enough to get 12 or bigger tanks I certainly do so, but often its out of my hands and I am stuck with a single 10 litre tank.

Can I consider buying a small pony bottle to extend my time? take the pony bottle and the 10 litre tank together for gas planning (ie not for redundancy)
What is the DIR answer keeping in mind that doubles and larger tanks are not an option in this case.

BTW the diving would be in simple open water recreational limits, less than 30 meters depth.

Thanks in advance.

 

[ianr33]

I am not DIR trained The answer to your question is NO.

 

[Rick Murchison]

I am not DIR trained The answer to your question is NO.

Or, put another way, what you describe is decidedly not DIR. If you'd like to discuss its efficacy as a general diving practice we can move the thread out of the DIR forum.
Your call.
Rick

 

[Doc Intrepid]

Can I consider buying a small pony bottle to extend my time? take the pony bottle and the 10 litre tank together for gas planning (ie not for redundancy) What is the DIR answer keeping in mind that doubles and larger tanks are not an option in this case.

The DIR answer is no, you cannot.

There are occasions when the demands for back up gas may be sufficiently stringent that divers use stage bottles for the initial portion of their dives, reserving backgas for emergencies.

But you're not talking about this.

The DIR answer to any combination of a single tank of backgas PLUS a "pony bottle" (terminology which is not compatible with DIR diving) is simply 'no'.

This thread is closed.

Thank you,

Doc