DIR and PONY's

[ScoobieDooo]

Why is DIR opposed to PONY's for SINGLE TANK recreational divers?

Why?

 

[detroit diver]

If you are managing your gas properly, and you have a buddy, there is no reason to have a pony bottle.

 

[ScoobieDooo]

What if both of you were to get seperated and an OOA took place?

 

[bwerb]

In the DIR system, teamwork is paramount. You cannot be diving DIR and have either of the two events happen at the same time...well, I guess technically ANYTHING CAN happen, but the DIR stance is that the cascade of screw-ups which would have to occur to result in a simultaneous buddy loss and OOA if you are truly utilizing and dive planning with DIR principals is negligible. On the otherhand, one of the tenents of DIR is to reduce complexities. If you are carrying a pony as the solution to the problem, you could be seen to be solving the wrong problem and instead adding and additional complexity.

At least that's how I understand the logic (I am not an expert at all on this...so don't take this as the definitive answer...)

Brian

 

[runvus4]

A lot of people are anti-pony bottles, not just DIR.

Figure two types of diving

1) General open water non-overhead dives. If you have a failure, then you can always do an emergency ascent (controlled or not), thus you do not <edit> need </edit> a pony. It may be nice and re-assuring to have, but since DIR is into very streamlined setups, leaving everything not needed behind, they, and lots of others, dont' want to spend the money, allocate portage space/weight, or dive with a pony.

2) Overhead dives (soft or hard). If you have a failure and can't do an emergency ascent, then most Pony's generally do not contain enough gas to get the diver safely to the surface, thus the pony provides false safety and should not be carried. Gas redundancy is handled by doubles, h-valves, buddies safe second, and stage bottles/bailout bottles.

The only difference I can see between a "pony" and a "bailout bottle" is mainly terminology associated with volume. They are the same concept in that you have a totally redundant tank/regulator set to provide redundant gas to the diver in the case of primary tank failure Unfortunately tanks designated as "pony bottles" are usually low volume and a "bailout bottle" is usually sized to get the diver to the surface safely and thus much larger than "pony bottles". If for example you carried a AL40 or AL80 slung stage style that had enough gas to properly get you to the surface safely from an overhead situation and called it a pony, then I don't think that anyone will be opposed to the bottle itself though they may not agree with the terminology.

 

[detroit diver]

runvus4 once bubbled...
.......... It may be nice and re-assuring to have, but since DIR is into very streamlined setups, leaving everything not needed behind, they, and lots of others, dont' want to spend the money, allocate portage space/weight, or dive with a pony.........

While I agree with most of what you posted, money and portage space/weight have nothing to do with it as far as DIR is concerned.

 

[MikeFerrara]

I think...If your doing dives where you feel you need more gas of redundancy doubles are the way to go. OTOH, if your doing dives where you don't need redundancy why bother.

I rarely dive in a single tank but I have a couple set up with H-valves. The arangement provides some redundancy I just move my gear (without any changes) from the doubles to the single.

I don't have a clue what DIR or anyone else has to say about H-valves and I don't care. Something I have given thought to over the years is what if you have a reg failure in a teaching situation? You can't just surface and hope the class follows. You could share with someone but that puts limits on your mobility and positioning in relation to the class. I would just shut down the offending reg and switch. I would still end the dive but there wouldn't be any hurry and I wouldn't be tied to anyone. IMO, teaching represents something of a virtual overhead in that your ability to surface may be delayed. BTW, I am aware of several instances of instructors leaving classes for one reason or another which IMO is totally unacceptable.

I have heard all the arguments regarding travel. I prefer to dive my own stuff including tanks but if I do travel I only do dives that I think are appropriate for the equipment that's available. I just don't do dives that require redunancy unless I have it.

 

[Genesis]

is the potential for a burst-disc failure. While a tank neck O-ring can fail too, the gas escape rate is limited by the threads around the valve if it happens, and its more likely to be a leak than an explosively rapid gas loss.

A burst disk failure underwater could be very bad, but I don't know how common that possibility is. I have seen them fail while a tank was being filled, and at nowhere near maximum pressure, at one of the LDSs in the area.

 

[diveski01]

For some dive sites I carry a 30cuft stage bottle. Not for gas management, but only as a redundant air source in case of a valve failure - more along the concept of why divers use doubles.

 

[detroit diver]

diveski01 once bubbled...
For some dive sites I carry a 30cuft stage bottle. Not for gas management, but only as a redundant air source in case of a valve failure - more along the concept of why divers use doubles.

I'll bet you won't be doing that after May!!