Optimal Pony Bottle Size for Failure at 100ft?

[NW Dive Dawg]

I got to thinking about the original question on this thread... "What is the optimal Pony Size for Failure at 100Ft"

Well...... if I had and actual "Failure" at 100ft then I'd say that the optimal size would be a slung 80 AL filled with 34. That gives me time to set my alarm and take a nap before meandering slowly to a 20 or 30 minute safety stop and arrive back on the surface with 1500psi to spare.

I think the better question is...... "What is the Optimal Pony Size for NDL Dives to 100ft or less"...and for me the answer is a back mounted 19... So....that's what I use!

PS.... I also now have my pony 2nd on a bungeed necklace along with a small 2in SPG to be able to monitor status pre-dive and during dive.

 

[SlugLife]

Yet the seem to create almost as many problems as they solve. Maybe they aren't as valid as they appear.

What kind of problems does having redundant air create? How common and severe is each problem? And can the problem be easily avoided?

The problems I'm aware of are:

1. The diver uses the wrong regulator
2. The diver cannot find their other regulator.
3. The extra bottle and regs are extra weight/clutter.
4. Having redundant air may encourage a diver to engage in dangerous behavior.
5. The pony bottle may confuse an inexperienced dive-buddy needing air.
6. Anything not GUE is a death trap. Don't get me started ranting about those insane sidemount divers with dangling tanks! Magnets how do they work?

...and....

1. To my knowledge uncommon, not severe (just switch to the other), and easily avoided with practice.
2. This is no different than the dangling octo problem in standard configuration. Easily avoided.
3. Outside penetration diving (perhaps usually not wise solo), I consider this an excuse by lazy divers.
4. An idiot behind the diving-mask, is an idiot behind the diving mask. I've called spare-air's (3cu or less) dangerous, but 6cu and up is almost always better than nothing. It's perhaps a strawman to talk about the spare-air diver, in threads where someone is asking what size of pony they need.
5. Not severe, and we're talking about solo.
6. ...

Most of the above is remedied by some very simple and basic training, practice, and discipline.

 

[Lorenzoid]

My question would be....... do you believe that a pony is a better alternative than no redundancy at all?

Sure. To me, "no redundancy at all" would mean something like solo diving or unreliable insta-buddy diving.

 

[johndiver999]

Back mounted pony bottles are a line trap and make the rig much more prone to entanglement in line while underwater. It just seems to more than double the opportunity for entanglement since line can get down between the bottles.

 

[lostsheep]

@johndiver999

What is this “up button” you keep speaking of? Please tell me you aren’t using the lpi to initiate an ascent.

 

[CWK]

I believe they'd add that when there is a marginal solution to a problem and a good one, you should choose the good one -- even if the marginal one might be better than nothing.

I agree. However, we have a choice of a marginal solution, a good solution and an excessive solution…..

I have done the calculations. For a direct ascent to the surface from 30m, a Al6 at 200 bar contains sufficient gas for me. This is a marginal solution.

A Al13 at 200 bar contains just over twice the amount of gas that I will need to make a direct ascent to the surface from 30m, whereas a Al19 at 200 bar would hold just over 3 times as much gas as I would need. The Al13 and Al19 are good solutions.

A Al40 at 200 bar would contain about 7 times more gas than I would need to make a direct ascent to the surface from 30m. This is an excessive solution.

 

[johndiver999]

@johndiver999

What is this “up button” you keep speaking of? Please tell me you aren’t using the lpi to initiate an ascent.

Yup I only got two buttons on the bc, they really need a third, just like my transmission, wouldn’t it be nice to have neutral button??

Seriously though, if you want to ascend with little air use, it is far better to press the up button, rest and conserve air , compared to kicking and placing those large muscles into an oxygen consuming state. Especially for the initial part of the ascent where gas expansion is relatively slow and gas consumption is highest.

Not much different than those fanatics who proclaim it is essential to maintain a horizontal position and good trim when ascending; they’re positively bouyant as well when coming up.

 

[wetb4igetinthewater]

Back mounted pony bottles are a line trap and make the rig much more prone to entanglement in line while underwater. It just seems to more than double the opportunity for entanglement since line can get down between the bottles.

Like doubles?

And actually no. If a line goes across ones back, it isn't double the chance of a entanglement, just a small increase in probability of entanglement. But not double.

 

[lermontov]

I got to thinking about the original question on this thread... "What is the optimal Pony Size for Failure at 100Ft"

Well...... if I had and actual "Failure" at 100ft then I'd say that the optimal size would be a slung 80 AL filled with 34. That gives me time to set my alarm and take a nap before meandering slowly to a 20 or 30 minute safety stop and arrive back on the surface with 1500psi to spare.

I think the better question is...... "What is the Optimal Pony Size for NDL Dives to 100ft or less"...and for me the answer is a back mounted 19... So....that's what I use!

PS.... I also now have my pony 2nd on a bungeed necklace along with a small 2in SPG to be able to monitor status pre-dive and during dive.

how is it held on -looks like a couple of screws - can you change to a new al80 bottle for a second dive without hassles- you keep the two second stages on the primary rig?

 

[VikingDives]

@johndiver999

What is this “up button” you keep speaking of? Please tell me you aren’t using the lpi to initiate an ascent.

"Air Elevator?"