Pony/Stage Bottle for ANDI CSU

[Daryl Morse]

I hope this doesn't start a holy war, but here it goes...

I'm planning to take ANDI CSU, which covers up to two cylinders, up to two gas mixes (to a maximum of 50% O2) and maximum depth of 40m. Obviously if there are two cylinders and two gas mixes you are either diving independent doubles or using a pony/stage bottle.

I'm considering taking this course because I want to use nitrox to extend my bottom time and I also want to learn how to incorporate increased redundancy into my skill set for extra safety in 30-40m depth range, as an intermediate step to diving doubles and eventually taking an introductory deco procedures course. My intention is to acquire a 30-40cf sling bottle for use in the course and for diving afterwards. (I plan to discuss this further with my instructor as part of the course.)

I read numerous times that many people feel strongly that a pony bottle is only intended to use for surfacing in the event of an emergency or unplanned situation. So my question is where is the line between a "pony bottle" and a "stage bottle"? Obviously stage bottles for mandatory decompression are intended to be used. Is this a case of ANDI standards taking a different view of the use of a pony bottle or what? What's wrong with using proper planning for intentionally using a pony bottle to extend bottom time?

 

[Don Burke]

I read numerous times that many people feel strongly that a pony bottle is only intended to use for surfacing in the event of an emergency or unplanned situation. So my question is where is the line between a "pony bottle" and a "stage bottle"? Obviously stage bottles for mandatory decompression are intended to be used. Is this a case of ANDI standards taking a different view of the use of a pony bottle or what? What's wrong with using proper planning for intentionally using a pony bottle to extend bottom time?

The first references I have found to a stage bottle seem to indicate it was a bottle to be breathed down first to avoid using back gas, extending the amount of gas available for the dive.

A stage bottle was literally staged somewhere in the cave is by a support diver. They are usually sling rigged to make handling easier.

Somewhere along the way, any bottle sling rigged started carrying the name "stage bottle". This included deco bottles, which are often staged in caves, but are often carried for the entire dive in the ocean or lakes.

A pony bottle is a version of the bailout bottle, which is sized to get your butt out of trouble, not extend the dive.

My call is that 30cft and above, calling the bottle a pony is more a matter of grammar than procedure. Below 30cft, we are getting into bailout bottles and small deco bottles.