No such thing as a Pony Bottle

[PfcAJ]

It's super obvious when you do a dive on nitrox and then do it again on trimix. It's very evident when you do it at a site you're familiar with.

A great example is ginnie springs on a scooter (mitigates co2).

 

[MXGratefulDiver]

The real point I am trying to make is you aren’t likely to experience Narcosis at 130', even on your first dive. You are likely to be apprehensive and have elevated CO2 due rapid shallow breathing, which mimics a lot of Narcosis symptoms. I believe that divers would be better served with a more realistic representation of Narcosis rather than what amounts to scary sea stories.

Not been my experience. I've got over 3400 dives, am not the least bit apprehensive about diving, have very good gas consumption for an old, fat guy, and I have experienced enough narcosis at 130 feet to know I'm narc'ed.

I agree with you about the scary sea stories ... stories are really a way for an instructor to cover a required topic that they really don't understand. But in my experience, your blanket statements are just as imprecise in the other direction, and it serves no one to understate the potential risk by claiming that it won't happen. The truth is that it may or may not ... depending on the individual. In my deep class I simulate an OOA to gauge a student's responses at the deepest part of the dive. I've had students who, at 130 feet, do not respond to me slashing my hand across my throat. They just sit there and stare at me like they don't understand what I'm telling them. Imagine if that was your dive buddy ...

... Bob (Grateful Diver)

 

[Akimbo]

… I have experienced enough narcosis at 130 feet to know I'm narc'ed…

OK, but are you narked to the degree that is implied by the scary sea stories? Apparently not since you are here telling the tale and are content to return to 130' with students.

… But in my experience, your blanket statements are just as imprecise in the other direction, and it serves no one to understate the potential risk by claiming that it won't happen…

If you re-read my statements, there was never a blanket statement that “it won’t happen”. However, if it did happen with the certainty indicated by the OP’s dive shop, 130' would be too deep for the recreational limit.

… I simulate an OOA to gauge a student's responses at the deepest part of the dive. I've had students who, at 130 feet, do not respond to me slashing my hand across my throat. They just sit there and stare at me like they don't understand what I'm telling them. Imagine if that was your dive buddy ...

That is deviating from the premise of my initial comments that this conversation is based on. Everyone doesn’t experience clear symptoms of Nitrogen Narcosis at 130', as indicated by the OP’s dive shop. My contention from the beginning is that the minority don’t actually experience Narcosis symptoms even though most are distracted, apprehensive, and often using poor respiration technique. Most (not all) that do experience symptoms can often eliminate them by relaxing and proper breathing (at 130'). Therefore, it is not clearly Narcosis and could probably be reproduced at 60' under a heavy work load.

Instead of sea stories, why not just explain the facts?

• There is considerable variability
• Narcosis isn’t an on/off switch that makes divers lose their mind at 131'
• Mild symptoms consistently precede severe symptoms at shallower depths — unless your descent is very rapid to significantly greater depths than previously experienced.

Definitely explain the value of relaxing and deep ventilation breathing techniques plus how to use awareness and concentration to overcome symptoms. I see the objective of a “deep diving” course as providing students with the knowledge to slowly work to greater depths and to recognize their personal limits. It really doesn’t matter if it is 60', 130' or 165' like many European courses. What matters is they know enough to find their limits.

 

[Nemrod]

OK, but are you narked to the degree that is implied by the scary sea stories? Apparently not since you are here telling the tale and are content to return to 130' with students.

Not nearly as scary as hallucinating and looking down and seeing a pony bottle slung along your side. When that happens you know you are having Rapture of the Deep. And that is scary. Sometimes I actually see myself rigging the pony bottle and then practicing with it and I once even used an imaginary pony bottle through an entire Solo Diver course. Now I realize, it never happened and I was just under the influence of nitrogen under pressure. Yep, that explains it, we all know pony bottles do not exist.

Wow, this is thread drift worthy of narcosis, started out with the premise of an imaginary instructor who in an abstract and postulated situation refused to accept the existence of pony bottles and now we are narc-ing due to the effects of ambient lighting and imagining ponies.

Maybe we should all just kiss and make up, well, y'all kiss and makeup, I will just quit pretending I just bought a new pony bottle.

N

 

[muddiver]

You are completely over thinking the issue. A reserve gas supply is only what you need to get to the surface.

If you want to factor in a decompression profile, and add a thirty minute safety stop, then go look up "rock bottom" gas management, which is really over-kill. All you need from 33 meters is 13 to 15 cubic feet of air. It's a fast, no stop ascent to the surface because some thing went wrong, not a leisurely ascent, punctuated by stops. If you think you need all that, take a decompression diving class and plan all your gas to the cubic inch. A pony is an "oh ****!" I gotta go! Last resort.

 

[The Chairman]

Instead of sea stories, why not just explain the facts?

• There is considerable variability
• Narcosis isn’t an on/off switch that makes divers lose their mind at 131'
• Mild symptoms consistently precede severe symptoms at shallower depths — unless your descent is very rapid to significantly greater depths than previously experienced.

This is so incomplete:

• Narcosis is often invisible to the diver affected. You can't tell if you're narced. Narcosis is a gradual dumbing down of the diver largely through perceptual narrowing. Rapture of the deep is overblown. Stupidity is the normal affectation.

 

[Kharon]

I will, however, say that I think the current method of having someone solve puzzles or write their name backward or some of the other acts of stupidity that dive instructors call "tests" on the deep dive serve no useful purpose. They're artificial data points, since no one's ever going to do those things on a real dive ...

+1. Nor have they done it enough for it to be natural. Those tests are as valid as having someone back rapidly through a winding course of cones several times, recording their time. Then getting them drunk and making them do it again. Totally bogus. It would be much more valid to give them a task that they do naturally and frequently and run the test that way. Something that is unnatural cannot be learned and done proficiently in a couple of trials. These tests are set up specifically to prove a point - biased as hell.

 

[Akimbo]

This is so incomplete:

• Narcosis is often invisible to the diver affected. You can't tell if you're narced. Narcosis is a gradual dumbing down of the diver largely through perceptual narrowing. Rapture of the deep is overblown. Stupidity is the normal affectation.

I concur, it is incomplete. There’s only so much you can yak about. That is why I believe that people need to experience Narcosis for themselves, gradually and under manageable conditions. Unfortunately a significant number of people don’t perceive anything at 130', or symptoms are so subtle that they think they have an unusually high tolerance.

“Perceptual narrowing” is the most frequent symptom I have experienced, observed in others, and hear reported by other divers. Fortunately, it is comparatively easy to recognize those symptoms and take action to manage them compared to most intoxicants. I am blessed with a strangely reliable Narcosis indicator, my lips start to numb and tingle. My field of vision also slightly narrows but I can’t tell when I’m wearing a mask.

I guess it is worth discussing the management of Nitrogen Narcosis for those who have not been trained to deal with it. First is to relax and control deep respiration, second is to consciously become more vigilant monitoring dive computer parameters (or equal), and third is to evaluate the level you are effected and consider ascending or aborting the dive… even that is over-simplified but hits the high points.

Wondering off Subject a Little:
It really is unfortunate that chambers are so expensive to purchase and operate. They are an invaluable training tool. Students can experience and observe things that they are just too distracted to get on their first dives in the water. One chamber dive with the help of a few training aids can easily demonstrate the following to several students at a time:

• What it feels like to clear their ears
• Physically see and feel the effects of Boyle's Law
• Observe simulated lungs (balloons) expand and explode on ascent
• Actually see and feel the effects of Henry's Law — heat of compression on descent and the cooling effect and fogging up an ascent.
• Hear the effects that increased gas density has on their voice… it doesn’t just happen in Helium atmospheres and has considerable entertainment value at first.
• Perceive the effects of breathing an increased air density, which is much harder in the water.
• Experience how Narcosis affects them without all the risks or distractions of being underwater. A few games often help and students can observe classmates through viewports.
• Rack up their first decompression dive before even getting wet.

We had to endure 16mm B&W 1940s-era movies taken inside a chamber in the Navy before getting wet or making a chamber dive. Yes, some of the above can be demonstrated visually but it just doesn’t have the impact of experiencing it.

A significant number of people don’t experience Narcosis at 130' — you don’t experience it if you are unaware of it. But everybody does at 200', especially without the distraction of being in the water and watching a video of themselves later.

 

[Mike]

+1. Nor have they done it enough for it to be natural. Those tests are as valid as having someone back rapidly through a winding course of cones several times, recording their time. Then getting them drunk and making them do it again. Totally bogus. It would be much more valid to give them a task that they do naturally and frequently and run the test that way. Something that is unnatural cannot be learned and done proficiently in a couple of trials. These tests are set up specifically to prove a point - biased as hell.

I think the purpose of the exercise is singularly only to educate the diver that you can be impaired without knowing it, the 'testing' material is irrelevant, the benefit is the awareness that is gained.

 

[Storker]

I've done the mistake of discussing with someone with several thousand dives before, so I guess I'm setting mysef up for some serious bashing here. But, dude, what you're claiming is contrary to everything that's known and published about nitrogen narcosis.

Most won’t feel much of anything and those that believe they might are likely to feel the results of apprehension and elevated CO2 far more than Narcosis. Training agencies chose 130' as a recreational depth limit because Narcosis is so minimal for the great majority of people, in addition to being near the edge where staying within NDLs is reasonable.

What kind of narcosis are you talking about here? The stupid drunk we all hear stories about during OW class, with antics like trying to donate air to a passing fish? Or the mental tunnel vision and sluggishness that starts to creep up on most people already before 30m/100ft, but which an experienced diver usually doesn't feel because he's got enough spare mental bandwith that the slight impairment isn't noticeable unless someting happens that requires all available mental capacity?

At work, I use my brain rather than my body. Sometimes quite hard. And if I'm going to work in the evening, I don't even allow myself a single beer for dinner because I've noticed lots of times that that single beer is enough to take the edge off my thinking. I don't feel drunk, I don't even feel tipsy, but I know that I'm losing my edge. And since I'm very much aware of my mental capacity, I can quite easily notice when my mind doesn't run at full speed. Same thing with narcosis. Somewhere below 25m/80ft, I start noticing that I'm losing the keenest edge of my mind. It runs slower, and I have to concentrate just a little more to avoid mental tunnel vision. Sometimes, I have to check to notice, other times it's quite noticeable above 30m/100ft.

It's the same as with drunk driving. Every frikkin' test has shown that a BAC of less than 0.05% will impair the driver, dulling reflexes and reducing the ability to multitask. Even so, quite a few drivers will claim that they can drive just fine, even after several beers or glasses of wine. Sure, if your only task is to keep the car on the road. But if you need to handle an emergency, you might well be scr€wed. How about you? Since you claim that no-one is narked above 130ft, do you think it's OK to drive with a BAC level of 0.05-0.1%?

Same thing with a rec diver with moderate experience: He might feel just fine, but he's got enough mental tunnel vision to be unable to handle an emergency he hasn't trained and drilled for.