Do you actually see people diving with pony bottles?

[johndiver999]

I am trained to use it, but only in a certain way--as one large tank--at this juncture in my road to being fully tech-trained. I believe there are divers out there who are content to use doubles as one large tank for purely recreational dives, and per the rec protocol, simply call the dive and ascend upon a failure. (For all I know, there are some who believe they know how to do valve shutdowns and are simply not very good at it. Are they more safe than we are on this kind of dive?) Anyway, my point is that my buddy and I have our emergency protocol for rec dives down pat, and we don't need some NJ dive boat's "requirements" telling us how to dive. If it's a rec dive, i.e., direct ascent to the surface is possible, then we're good to go as far as we and our training agency are concerned.

Having two sets of regulators without the ability to shut one down if a problem arises would seem to be increasing the probability of a failure without realizing the potential benefit of the second set of regulators? Is that safer than a pony?

 

[Storker]

Your doubles have an isolation manifold, but you don't know how to use it and would not use it in an emergency? Is that a DIR idea to use a type of gear you are not yet trained to use? I'm confused?

Also in my part of the world, doubles are rather popular among rec divers. Usually, it's twin 7L 300 bar or twin 8.5L 232 bar, which both carry some 4000 effective surface liters (or about 140 cu.ft, for those who are metrically challenged). That isn't a tech twinset, it's a huge rec tank. Which may come in handy if you're diving dry in cold water, are a hoover and want to stay below close to your NDL on EAN32 without running out of gas. That those twinsets routinely come with an isolation manifold is purely incidental. They're still - in practice - high capacity single tanks with a COG noticeably closer to your back than what a 12L single has.

EDIT: And a 12L 300 bar single (nicknamed a "long twelve" around here) carries about 3200 effective surface liters (or about 110 cu.ft)

 

[gcarter]

I just thought I would add this point.

Regulators failures are rare, especially mechanical failures of the first stage. However, I have had a buddy have a catastrophic failure of a first stage, as others have also discussed here.

Most problems are either hose failures. Or Free flows.
Free flows are generally occur in cold water. This is due to ice forming, either in the second stage or first stage. The ice forces the valve open.
Ice formation is due to the gas freezing any water molecules in the air within the regulator. The gas temperature drops as the pressure drops from high pressure to low pressure through the first and second stages. This is what causes the freezing. First stages are designed to heat sink, actually warm the first stage from the surrounding enviroment. An issue with the early generation of composite material first stages was they failed to conduct the cold away from the internal mechanism and where more prone to freezing.
Thinks that significantly increase the risk of freezing are.
1. Cold regulators (storing them in the car overnight in cold weather).
2. Water vapour within the air in the cylinder.
3. High gas flows. (The faster -more- gas that flows through the first stage, the colder it will get and the increased risk of freezing).
4. Breathing off the first stage in very cold weather PRIOR to submerging (The exhaled breath introduces water vapour into the second stage, which is a potential freezing point).

Point 3 is important.
Venting a first stage, for a prolonged periods of time increases the risk of free flow. i.e. Filling a DSMB.
Heavy breathing increases the risk.
AND IMPORTANTLY - two people breathing off a first stage doubles the gas flow (even if they are both relaxed - the likely hood is the Out of Gas diver will have an elevated breathing rate). This significantly increases the likelyhood of a free flow in cold water.

A point to remember - once the second stage ices open, the first stage will ice open very quickly afterwards.

I have witnessed this issue a number of times.

Example 1.
Two Pairs started a 35m (105feet) dive in a freshwater quarry in February in cold fresh water.
Pair 1 one diver had a freeflow. He switched to his buddies AS. As they started the ascent, the buddies regulators started to free flow. The second pair assisted, each taking a buddy on to their AS. One diver immediately switched from his primary regulator to his pony. All four divers commenced the ascent.
At approximately 10m the pair sharing the same first stage had another free flow. They made the surface OK.
The other pair stopped at 10m did a short stop, then ascend. One on the pony, one on his buddies AS.

After exiting, checking they where all OK, they decided that any more diving was probably not advisable, so retreated to the pub.

Example 2.
On a winter dive. I looked up at my buddy, air was slowly dribbling from his second stage exhaust port. As I closed on him, the rate of air leaving the exhaust increased. As I presented my long hose regulator, his regulator disappeared in bubbles as the first stage iced fully open. We made a controlled ascent.
We dived a bit later having swapped to a new regulator set.


This is part of the reason British divers like their Twinsets (Doubles) or Pony's

I will add one other thing I have seen trigger a free flow - adding air to a dry suit while inhaling. I would expect adding air to your wing on the inhale could do the same thing. Similar to the buddy breathing scenario, it is the increased airflow. In the case I witnessed, I think she waited too long to add air to her suit and so the addition was more than just a quick puff. Just enough to reach the tipping point.

 

[Lorenzoid]

Having two sets of regulators without the ability to shut one down if a problem arises would seem to be increasing the probability of a failure without realizing the potential benefit of the second set of regulators?? Is that safer than a pony?

"Safer"--I dunno. I believe that because I practice and practice doing OOA emergency ascents with my buddy, I am safer than someone who brings along a pony because a dive boat requires it yet isn't practiced at using it.

Additional failure points--okay, maybe. But I would weigh risk versus benefit: The probability of a failure is low, and in the event of a failure I ascend on my buddy's donated air, just as I would with a single tank, so in that sense the risk is no higher. Again, we're talking REAL buddy/team diving, not solo and not unknown insta-buddy diving (same as solo as I see it). The benefit is a lot of gas. I think the benefit outweighs the risk.

As I think I said way in the beginning of this thread, I have nothing against ponies. My system provides an alternative to a pony--it provides the redundancy that some rely on a pony for--that's all.

 

[johndiver999]

"Safer"--I dunno. I believe that because I practice and practice doing OOA emergency ascents with my buddy, I am safer than someone who brings along a pony because a dive boat requires it yet isn't practiced at using it.

Additional failure points--okay, maybe. But I would weigh risk versus benefit: The probability of a failure is low, and in the event of a failure I ascend on my buddy's donated air, just as I would with a single tank, so in that sense the risk is no higher. Again, we're talking REAL buddy/team diving, not solo and not unknown insta-buddy diving (same as solo as I see it). The benefit is a lot of gas. I think the benefit outweighs the risk.

As I think I said way in the beginning of this thread, I have nothing against ponies. My system provides an alternative to a pony--it provides the redundancy that some rely on a pony for--that's all.

I’m unsure how you make the jump from carrying excess capacity (in the form of two tanks) is synonymous with redundancy. I agree there are people who dive with gear they don’t practice with enough to utilize in an emergency.

 

[Lorenzoid]

I’m unsure how you make the jump from carrying excess capacity (in the form of two tanks) is synonymous with redundancy.

See posts #679 and #681 above. The thing about NJ dive boats requiring a pony or doubles for redundancy--not necessarily for extra capacity--is why I jumped back into the thread.

 

[barth]

Having two sets of regulators without the ability to shut one down if a problem arises would seem to be increasing the probability of a failure without realizing the potential benefit of the second set of regulators? Is that safer than a pony?

It’s hard to tell what is safer.

When his buddy is oog he can use gas for his buddy and himself until the doubles are empty.

When somebody is using a single tank and a pony for Sharing gas, one tank will be empty before the other tank is empty.

When you are going ndl dives it doesn’t matter if you are using doubles or a single tank. The plan can be the same. You can go to the surface without fixing the problem. Sometimes that is better than closing the wrong valve by yourself or your buddy.

When you are diving cold water it would be better when your buddy is oog that you and your buddy have their both their own first stage to avoid freezing/free flowing.

When I was doing rec diving before tech and/or cave trained I was using doubles just for more volume than a single tank. There is nothing wrong with that.

I think there is also nothing wrong when somebody is doing solodiving and is using a single tank + pony.

But if you want to compare a buddy team with doubles and a buddy team with single tank + pony it is hard to tell what is safer. Equipment is just a part of safety.

When dives are more demanding, equipment is still just a part. It’s about equipment, training, experience and planning.

For 30 minutes at 30 meter/100 feet openwaterdive I don’t need doubles and a Bottomstage. Bringing more equipment doesn’t make the dive safer for me.

 

[lermontov]

GUE makes everything hard.

The youll know what the next question is...why?
off topic but.. I heard of a team of GUE dives that was exploring a wreck that im very familiar with recently not sure if its GUE or this particular group but they dont use lines for penetrations. One ccr diver got lost inside the wreck and spent 3 hours trying to find his way out - he shot an smb out of a small port hole and a buddy noticed he was overdue and went to see what the problem was ( yes he was solo after being seperated) - the diver was on his bailout and fortunately the second diver was able to smash a window and pass some more gas to him while others went in to rescus him...
and heres the punch line...
he still thinks you shouldnt have to use a line, that progressive penetration is the only safe way

 

[Diver-Drex]

"Safer"--I dunno. I believe that because I practice and practice doing OOA emergency ascents with my buddy, I am safer than someone who brings along a pony because a dive boat requires it yet isn't practiced at using it.

Additional failure points--okay, maybe. But I would weigh risk versus benefit: The probability of a failure is low, and in the event of a failure I ascend on my buddy's donated air, just as I would with a single tank, so in that sense the risk is no higher. Again, we're talking REAL buddy/team diving, not solo and not unknown insta-buddy diving (same as solo as I see it). The benefit is a lot of gas. I think the benefit outweighs the risk.

As I think I said way in the beginning of this thread, I have nothing against ponies. My system provides an alternative to a pony--it provides the redundancy that some rely on a pony for--that's all.

- You’re safer trained on your equipment than someone who is untrained on theirs. You realize this means nothing?
- YOU have NO redundant gas. Your buddy has gas for you in the event of catastrophic loss of your gas. Unless you’re separated. This is no better than what two brand new OW divers have.
- The risk of being blown off a wreck and separated from your buddy in low vis water is why NJ divers carry redundant gas. Entanglement risk is why NJ divers carry redundant gas. It is not about some captain making rules. It is the reality of diving here.

 

[Diver-Drex]

See posts #679 and #681 above. The thing about NJ dive boats requiring a pony or doubles for redundancy--not necessarily for extra capacity--is why I jumped back into the thread.

What exactly is your issue with it? I don’t quite understand why you object to a widely accepted best practice of carrying a redundant gas source in dive conditions that warrant it? I am curious as to what the hangup is? I suspect it is because GUE doesn’t do it that way, it’s not DIR or something along those lines. I base that on your “GUE makes everything hard” quip. That’s fine with me if that’s your reason, we don’t dive together.