Is there a valid reason for a pony bottle

[2airishuman]

What's the difference between isolated doubles and a pony? I mean, in terms of gear. I understand that from a planning point of view, isolated doubles are closer to a stage bottle than a pony, but from a redundancy point of view, it's the same thing, right?

::shrug::

The idea with isolated doubles is that they are, well, doubles, that is, identical in terms of their size, contents, and how they are carried. In most cases one is connected to the BC and the other is connected to the drysuit (if used and if a separate inflation bottle is not used). Each cylinder has an SPG that is visible during the dive so that the diver can assess the condition of each cylinder.

During the dive, you alternate regs so as to keep the amount of gas roughly equal in the two cylinders.

With a pony, well, by definition, it's smaller than the primary cylinder, and it's not connected to anything except a second stage, and maybe an SPG, which may or may not be visible during the dive. For most people it's a reserve only and it's neither part of the gas planning process (except as a contingency) nor is it used on an alternating basis during the dive. If it's a stage, ordinarily, you use however much of it you plan to use at a particular point in the dive, rather than alternating with the primary; in technical diving, it may have a different mix.

 

[CWK]

Manifolded doubles with an isolator valve. For the dives I was making, double 120s and stages were necessary. I wasn't carrying around any "extra" gear on those dives. A pony would have been a fifth tank in the way.
Although two posters here keep harping the same thing over and over, I don't care if anyone wants to use a pony, just not on my boat. I feel they are a redundant piece of gear for a situation that is so rare that it will likely never happen to anyone involved in this thread. If it brings you peace of mind, haul it along with you on every dive.

An octopus is a piece of redundant gear. Do you ban them from your boat too?

If you have 2 regulators on your manifold doubles, you have redundant gear. Do you dive manifold doubles with only one regulator?

 

[Todd Whitworth]

When I'm alone, I always have someone at the surface, (that doesn't help when an emergency happens at a depth I know.) How I deal with that is I never go below CESA depth. I leave myself the option to ditch my weights if I have too. But I prefer the buddy system and that's how I usually dive.

You solo dive in B.C. cold water with a single tank? To me that feels like russian roulette. No offense but sounds frightening if anything happens

 

[MaxBottomtime]

An octopus is a piece of redundant gear. Do you ban them from your boat too?
If you have 2 regulators on your manifold doubles, you have redundant gear. Do you dive manifold doubles with only one regulator?

This thread sure brings out the *******s. If you could read what I posted you would know that I banned ponies because the only person who dives on my boat with one abused it. He flooded it twice and also ran out of air twice. I did not ban it because it's a redundant piece of gear. What an asinine thing to say.
Two regulators on a set of manifolded doubles are there because one has a high pressure hose for the spg, a low pressure hose for wing inflation and a low pressure hose for the backup second stage. The other regulator has a low pressure hose for drysuit inflation and another for my primary second stage. Each regulator serves a purpose and is used throughout the dive. Neither regulator is there as abundant gear.

 

[CWK]

This thread sure brings out the *******s. If you could read what I posted you would know that I banned ponies because the only person who dives on my boat with one abused it. He flooded it twice and also ran out of air twice. I did not ban it because it's a redundant piece of gear. What an asinine thing to say.
Two regulators on a set of manifolded doubles are there because one has a high pressure hose for the spg, a low pressure hose for wing inflation and a low pressure hose for the backup second stage. The other regulator has a low pressure hose for drysuit inflation and another for my primary second stage. Each regulator serves a purpose and is used throughout the dive. Neither regulator is there as abundant gear.

For some strange reason, I am actually not surprised that you do not understand that the two regulator setup on a manifold doubles is a redundant system.

 

[MichaelMc]

Max, needing two first stages on your doubles because one happens to feed the BC and the other the drysuit, when those could both come off one post if needed, misses the essence of the question.

Why in your doubles do you have two second stages hooked to separate first stages that are completely isolatable? When only one second stage is used in the normal conduct of a dive. Surely the second is redundant, even from your definition.

 

[2airishuman]

Two regulators on a set of manifolded doubles are there because [...] Neither regulator is there as abundant gear.

I guess that's kinda true if you don't know how to work the valves.

 

[doctormike]

::shrug::

The idea with isolated doubles is that they are, well, doubles, that is, identical in terms of their size, contents, and how they are carried. In most cases one is connected to the BC and the other is connected to the drysuit (if used and if a separate inflation bottle is not used). Each cylinder has an SPG that is visible during the dive so that the diver can assess the condition of each cylinder.

During the dive, you alternate regs so as to keep the amount of gas roughly equal in the two cylinders.

With a pony, well, by definition, it's smaller than the primary cylinder, and it's not connected to anything except a second stage, and maybe an SPG, which may or may not be visible during the dive. For most people it's a reserve only and it's neither part of the gas planning process (except as a contingency) nor is it used on an alternating basis during the dive. If it's a stage, ordinarily, you use however much of it you plan to use at a particular point in the dive, rather than alternating with the primary; in technical diving, it may have a different mix.

Gold star!

I think that you missed the question I was raising with Max. Perhaps I should have used the term independent doubles instead of isolated doubles.

Independent doubles: two tanks, each with a first stage, a second stage and an SPG.

Single tank and pony/stage: two tanks, each with a first stage, a second stage and an SPG.

How you carry and dive them is up for discussion, but from a schematic point of view, they are the same. That's all I was saying.

 

[BRT]

I usually dived with twin 120s, a 40 with 50% and another 40 with 100%. If I ever had to shut down the isolator, I would still have access to both tanks. A pony is a smaller tank that you would go to in the event of a total and instant loss of gas. There are more airplanes falling from the sky than total first stage failures. I'll take my chances.

Ha ha. Here is the guy diving with 4 tanks saying other people should only dive with one.

 

[MaxBottomtime]

Four tanks are required for some dives. For recreational dives, one will suffice.