Is there a valid reason for a pony bottle

[doctormike]

A Spare Air is a trade name for a tiny bottle which I believe holds about 1.5 cu.ft. of air and is basically useless as a pony bottle and what I believe was being referred to in the post you responded to. If you read my posts you will see I am an enthusiastic promoter of the use of an appropriate pony.

Exactly.

And if the plan was to deal with a blown tire on your pickup truck by carrying around a bicycle wheel and using it to drive home at highway speeds, death-in-the-trunk would be a good name plan for that as well. Even though "it's better than nothing".

 

[johndiver999]

now with much more capacity:

Spare Air - Support Directory

 

[grf88]

now with much more capacity:

Spare Air - Support Directory

Wow, maybe we can find some bands and a manifold to double them up.

 

[Coztick]

Wow, maybe we can find some bands and a manifold to double them up.

Or add a third or fourth for deeper stuff.
A scalable pony system....dibs on the patent!

Well I'm off to the drawing board...hmmm?

 

[MaxBottomtime]

Contents gauges where not readily available during the J valve era. Thats why they had J valves.
J valves remained popular for poor visibility diving (commercial diving).
The 'false' activation of J valves was a well known weakness. The result - a frantic swim for the surface.
The other issue was the 'activating arm' sometimes came free from the valve.

If you look at the older diving books, there is a signal for J valve failed to operate. Although I guess out of air would also be valid.

A lot of the commercial boys used to carry pony's for exactly that reason. Some are still required to carry them on surface supply, it gives them a chance to get back to the bell if they loose surface supply.

I began my diving career using 72s with J valves. I understand how they work. I was referring to the fact that he ran out of air after getting snagged in the net. An spg would have let him know he was already low on air before swimming under the net. In that incident, a simple spg would have served him more than carrying around an extra tank and reg.

 

[scubadada]

I could do a direct ascent to the surface, at twice my average RMV, at 30 ft/min, from 90 feet, with 6 cf. Yes, better than nothing, but not right

 

[tursiops]

I began my diving career using 72s with J valves. I understand how they work. I was referring to the fact that he ran out of air after getting snagged in the net. An spg would have let him know he was already low on air before swimming under the net. In that incident, a simple spg would have served him more than carrying around an extra tank and reg.

That's not quite what he said...he wasn't low on air when he entangled in the net, he just inadvertently pulled the J-valve down in the net. then later when it got hard to breathe, he was actually low on air rather than having a reserve.
So, an SPG would have helped AFTER the net encounter, but not before. Which also obviates the need for a J-valve....which is why they are gone and we are using SPGs. Your post is a bit in the genre of "if we had some ham we could have some ham and eggs if we had some eggs."

 

[MaxBottomtime]

"I untangled my valve from the net by taking off my tanks off and swam out of the wreck with my tanks under my arm handed off my camera and put back on my tanks, then I was out of air."

That doesn't sound like low on air to me. Either way, an spg would have stopped him from getting into the situation in the first place. Like many of the arguments for ponies in this thread, the out of air could have been avoided by simply knowing how much air you have.

 

[KenGordon]

As a matter of interest who participating on this thread has had to share air in a full-blown emergency. I am not talking about practising air shares, they are easy, but having to help a diver in full blown panic who was clawing for the surface. This doesn't have to be your buddy but could be another diver in a group who picks you to mug as has happened to me. He was not even a member of the group I was with. Maybe if he had a pony he would not have put me at risk.

I have had to share air diving singles. No panic, no crawling, just a diver asking and being given gas. I have also messed up by starting with less than adequate gas, overstaying and needing to borrow gas for deco. No drama there. None of these were emergencies, running out of gas is only an emergency if the mitigations are not in place.

 

[dead dog]

Wow, maybe we can find some bands and a manifold to double them up.

Someday, who knows.