Snuba in Cozumel?

[PadiPro555]

You wonder how someone's life really is going when they feel the need to attack on Social Media, or chat rooms. As I was saying 33 feet is a full atmosphere. SNUBA is about getting people introduced to diving. I'm sure your boy will love it. I'll leave it to the Jac Cousteau's on this blog to criticize that too.

 

[JohnN]

[

If this is such a dangerous issue how has nobody been injured on snuba due to an expansion injury. Nothing beats the law of averages over time so what's the missing element?

 

[JohnN]

You wonder how someone's life really is going when they feel the need to attack on Social Media, or chat rooms. As I was saying 33 feet is a full atmosphere. SNUBA is about getting people introduced to diving. I'm sure your boy will love it. I'll leave it to the Jac Cousteau's on this blog to criticize that too.

33 fsw is two atmospheres of pressure.

Give it some thought. . . if 33 fsw is one atm, what is the pressure at 0 fsw?

 

[bcaderunr]

If this is such a dangerous issue how has nobody been injured on snuba due to an expansion injury. Nothing beats the law of averages over time so what's the missing element?

As old pilots like to say: "It ain't the odds, it's the size of the bet."

 

[Jayfarmlaw]

I'm curious to know about the zero accident statistic.

Snuba - Wikipedia, the free encyclopedia

Not that I believe everything I read, Wikipedia is usually a good start.

Company Not Exonerated for Snuba Diving Death

It looks like there is some type of helmet based snuba and a standard 2nd stage regulator snuba. Perhaps with a helmet, there is no way to spit the reg in a panic scenario. i found posts on this site and Scubatoys as well dating back almost 10 years quoting the same statistic. I would want to know more about the training session before I would do it with my child.....but if I were right next to them, and they enjoyed a pool session, I would not rule it out automatically.

Good luck, safe travels!

Jay

 

[DjDiverDan]

If this is such a dangerous issue how has nobody been injured? . . . . Nothing beats the law of averages over time so what's the missing element?

What is missing is the number of Repetitions - the law of averages might not reveal itself with a small sample size. Specifically, repetitions with the very young - age 10 or below - users. Snuba itself is relatively recent, first patented in 1990, and not really widely available as a tourist activity until about 2000, later in some vacation destinations. And, while this is largely speculation, I would guess that the percentage of users under 10-12 years of age has been very small. If you tell an adult that it is dangerous to hold his breath while on the regulator, and dangerous to make a rapid ascent, and that the consequence of ignoring these rules could be serious injury or even death, the vast majority, maybe all, will take that to heart. Same with most 16-20 year olds. But below the age of 12, especially if you allow 8-year olds to Snuba, sooner or later one is going to panic, forget the rule, and dart to the surface while holding his breath. Maybe it's only a 1-in-1,000,000 chance or even less, but the probability is not zero, and the more 8-year olds you let do it, the more likely a mishap will ultimately occur.

 

[mmmbelows]

Not buying that. Adults are stupider than kids, that's for sure, just go onto youtube for 20 minutes!

If this has been in existence since 1990 (a quarter century) (estimated at 5,000,000 dives) without a lot of expansion injuries reported there is something missing, it's either somehow they aren't reported or they aren't happening, if they aren't happening there is something missing in the math on how dangerous it is. An actuary would look at a zero out of five million odds as the risk doesn't exist.

 

[deepsea21]

True, but the greatest PERCENTAGE increase, on a per foot basis, is near the surface. Since volume of a gas is inversely proportional to pressure, a 33% decrease in pressure, going from about 16 feet (1.5 atm) to the surface (1 atm) results in a 50% increase in volume. But going from 33 feet (2.0 atm) to 16 feet (1.5 atm) is only a 25% decrease in pressure, and only a 33% increase in air volume. So the closer to the surface a diver is, the greater the percentage change in both pressure and gas volume for every foot of change in depth. It's not the absolute pressure that is dangerous, it is the Delta V - the rate of change in Volume of air expressed as a percentage. And that percentage rate of change function is NOT linear.

DiverDan is absolutely correct... Every 33 feet you add 1 atmosphere of pressure but the most dangerous effects from holding a full breath and rising 1 atmoswhere is from 33' to 0' which equates to a 100% increase in air volume. Think of it this way... at 33' a full breath of compressed air = 2 full breaths at the surface. At 66' its 3 breaths (not 4), 99' its 4 breath's (not 8) and 132' it's 5 breaths (not 10). As such, holding a breath from 132' to 99' and rising 1 atmosphere results in a significanly lower volume expansion... about a 25% expansion I believe vs: a 100% expansion from 33' to 0'. Maybe DiverDan knows the formula for the exact % of expansion from 132' to 99'. This is why you may be diving and a rise from 80' to 50' has little noticiable effect but that rise from 33' to 0' you can feel your ears popping, sinuses making noises, etc. There is a reason the last and most effective safety stop is at 15'... From 33' to 0' all the microscopic bubbles in you double in size.

 

[ggunn]

True, but the greatest PERCENTAGE increase, on a per foot basis, is near the surface. Since volume of a gas is inversely proportional to pressure, a 33% decrease in pressure, going from about 16 feet (1.5 atm) to the surface (1 atm) results in a 50% increase in volume. But going from 33 feet (2.0 atm) to 16 feet (1.5 atm) is only a 25% decrease in pressure, and only a 33% increase in air volume. So the closer to the surface a diver is, the greater the percentage change in both pressure and gas volume for every foot of change in depth. It's not the absolute pressure that is dangerous, it is the Delta V - the rate of change in Volume of air expressed as a percentage. And that percentage rate of change function is NOT linear.

Yes, I know. I have a BSChem.

 

[nodakdive]

You wonder how someone's life really is going when they feel the need to attack on Social Media, or chat rooms. As I was saying 33 feet is a full atmosphere. SNUBA is about getting people introduced to diving. I'm sure your boy will love it. I'll leave it to the Jac Cousteau's on this blog to criticize that too.

Actually, what you said was, "Probably for the fact that your not even at one atmosphere it's relatively safe.". All the Jac's read that and know that this is absolutely not the case, and it's a dangerous mis-statement. One of the most important concepts taught in OW courses has to do with pressure. You don't need to be a Jac to know and understand the danger. You don't need to attend more than the first OW class to know it. Thus, everyone loses it.

So, to be clear, if you're laying on the surface of the ocean or standing on the beach, you're at 1 atmosphere, not less than ("not even") 1 atmosphere. As soon as you descend beneath the surface, you're at more than 1 atmosphere. At 33 feet deep, you're under 2 atmospheres of pressure. So, if the hose is 30 feet long and you're as deep as you can go, you're "not even" at 2 atmospheres, but as has been pointed out, that's the biggest danger zone when it comes to lung over expansion, because the percentage of change is the greatest in those 33 feet to the surface.

So, "33 feet is a full atmosphere" is only true if you're talking about 33 vertical feet of sea water. If you're standing on the beach at sea level, it's a matter of miles worth of vertical air, and the problem is for someone that doesn't know better, or who hasn't been trained, they might think that if you're 30 feet beneath the ocean surface, you're "not even" at 1 atmosphere. False, you're at almost 2 atmospheres.

Now, one could make an assumption that because you're "not even" at 2 atmospheres, it's relatively safe with regard to DCS (the bends), but under no circumstances can you say that "Probably for the fact that your not even at one atmosphere it's relatively safe." If you're using snuba as intended, to submerge, you're at "more than" 1 atmosphere, and that's where the danger begins, not with DCS, but with lung over expansion.

If you haven't already, you might want to show this thread to your boss. Your boss should be able to explain the intricacies to you in a way that you'll better understand not just the concepts, but why everyone here, on a scuba forum, is hammering away. It's really dangerous to not understand the effects of pressure with regard to breathing underwater via a regulator.

There have been some interesting articles regarding the whole "how young is too young to dive" issue. I spent a week on a live aboard with a 14 year old certified diver that I wouldn't trust to dive if it was my kid, and I mean, I wouldn't trust that the kid wouldn't freak and hold his breath on an emergency ascent. There were 24 passengers. 23 three of them, at one or more times during the week, yelled, "RJ!! Stop that!!!" 3 of us were yelling at once when the kid was using a fishing pole with a huge treble hook on it to try and pick that cap off one of the crews head, on a rolling 65 foot boat. For instance....