Recreational Pony Bottles, completely unnecessary? Why or why not?

[inquis]

Does any agency still teach/execute an actual CESA skill -- from depth to surface? To my limited knowledge, they are all "simulated" with horizontal swimming, trickling a few bubbles as they go. As such, I suspect a significant fraction of people who need to do an actual CESA will do it... poorly. In fact, a quick google turned up that nearly 1 in 3 fatalities in 2009 "involved emergency ascents that had gone wrong".

 

[wetb4igetinthewater]

Does any agency still teach/execute an actual CESA skill -- from depth to surface? To my limited knowledge, they are all "simulated" with horizontal swimming, trickling a few bubbles as they go. As such, I suspect a significant fraction of people who need to do an actual CESA will do it... poorly. In fact, a quick google turned up that nearly 1 in 3 fatalities in 2009 "involved emergency ascents that had gone wrong".

PADI still requires it. SSI/SDI are optional. Can't speak for other agencies as I haven't taught for them.

 

[Bob DBF]

As such, I suspect a significant fraction of people who need to do an actual CESA will do it... poorly. In fact, a quick google turned up that nearly 1 in 3 fatalities in 2009 "involved emergency ascents that had gone wrong".

From that DAN article:

...emergency ascents, a rapid ascent (faster than 60 fpm) was witnessed or recorded. In 10 percent of emergency ascents, divers attempted a free ascent without using a breathing gas supply. Buddy breathing was involved in 8 percent of fatal emergency ascents. In the remaining cases, the mode of emergency ascent was not specified.

So emergency ascents are any ascent greater than 60 fpm.

10% made that ascent without using a breathing gas supply, which means, to me, that they abandoned their reg, which may supply a limited amount of gas on the way to the surface, a bad choice.

Buddy breathing is an acquired skill, if one hasn't learned and practiced don't try to learn in an emergency.

In the other 82% of cases they have no idea why the ascent occurred, which could anything from a runaway inflator to panic, which need not involve OOA.



A proper CESA is less than 60 fpm, and is a good trick in you can do it. I learned the emergency ascent (CESA) in my initial training and have practiced on a regular basis ever since. Without practice, the control is lost.

The submarine escape version is a buoyant ascent, and is extremely fast. Similar to fully inflating your BC at the boftom, bad move for a Diver, good one for a submariner.

 

[BlueTrin]

Every dive is different, if conditions and the dive plan are calling for it, you can use redundant gas. But I also do not think it is right to say better to have redundant gas. Selecting right equipment for the dive is also a diver skill.
I glanced through bsac incident report from 2017 (last one listed here Annual Diving Incident Report) there are few free flows but no fatalities. Most of the divers seem to cope well with free flows using the octopus from the buddy.

Not a big difference but the last one is 2019.

 

[BlueTrin]

There’s no such thing as total gas failure ( instant) it’s a myth.

It happened in a local quarry last year. I know the buddy of the person who was in this incident and they both claimed the air supply failed shut.

There was an investigation but I didn’t hear any more information about the reason for the failure.

Incident in St Andrews Lake - Regulator failed shut

Kent Online article: Second diver airlifted to hospital in month (The article seems to imply that the diver was severely hurt, that was not the case, he was brought to the hospital just to be checked and everything was fine) An acquaintance told me yesterday that his buddy had to do a CESA...

scubaboard.com

 

[scubaozy]

You mean, "I haven't died yet." ?

Looking at how strange your response is, I take it that you mistook my comment. Is anyone diving without redundant gas is suppose to die? I am just pointing out that in reality 50% of the time you have direct access to the surface within your basic owd training.

Associating free diving skills with scuba depths is going backwards to the days when we would spend extensive time in the water practicing all sorts of shite. The expectation would be that you would be special forces ready when you got your certification.

I hear you and I somewhat agree. But I am a generation after and not rarely given the task to teach to folks who are in danger of drowning when they held a glass of water. Making a diver out of them in 3-4 days is tough. For them as well, so, in water prep as a part of basic training would have come handy.

What does "being able to freedive to your confidence as a scuba diver" mean?

1. Equalisation, you learn more ways to equlise, even hands free, which is a great asset especially in an emergency
2. You will learn to slow down your pulse, breathing and relax, if you are already good with your buoyancy yet still cannot further reduce your sac, this will get you to the next level.
3. You learn/get used to perform under time pressure, this is what usually happens during scuba accident, you cannot get gas, you will either swim up or to your buddy.
4. You learn to weigh your self perfectly for your target depth, you get a great understanding on correct weighting as there is no bcd to compensate.
5. More I free dive to the depths I scuba dive, the more I feel confident I can make it to the surface in an emergency. This is great way of preparing for an emergency without actually practicing cesa with scuba gear from depth.

...and it says nothing of your ability to do an emergency ascent from that depth, since you are supposed to be exhaling all the way. Anyone can do that, with or without freediving experience.

How do you practice it? Do you think it will work if you have not practiced it?
When I worked as a guide during the years solo diving was considered a sin, I would do safety briefing for every diver who checks in on the boat, often in groups. Usual warnings, such as watch your spg stay with your buddy etc. I also told the divers in case they want to abandon their buddy or solo dive, they are allowed to do so, only after they can demonstrate me a perfect cesa from 18m in their check dive. This was obviously a bluff (Its a quirk I learned from a colleague who was guiding on lob), my employer would probably let me go if I did anything of that sort . But it is quite remarkable that out of thousands of divers, noone actually called my bluff.
Anyone can do cesa? Well, I guess you have to swim up it no other option but more likely that one with free diving experience will be keeping his composure during that swim.

Freediving experience may even be a detriment, as the habit is to hold the breath on the way up.

So is swimming. We will not instinctively breath out, it is given you have to do it purposefully.

Not a big difference but the last one is 2019.

Sorry not on purpose, I had just scrolled down to the list in the pate. As you say, does not make a lot of difference. In 2019 there is another incident where diver run out of air because of using pony instead of main gas supply by mistake, so, 2019 is not a year of pony, either.

 

[Wibble]

Freediving is pointless. Using our brains to build technology to remain underwater for hours is the point.

 

[scubaozy]

Freediving is pointless. Using our brains to build technology to remain underwater for hours is the point.

Perhaps you better buy a submarine?

 

[Wibble]

Perhaps you better buy a submarine?

I have one. The invention of the aqualung enables me to remain underwater to enjoy looking at the fantastic sub-aquatic world for as long as I like.

Freediving: drop down, stay a few seconds, fly up.

It's like golf: spoils a good walk.

 

[VikingDives]

[It is] more likely that one with free diving experience will be keeping his composure during that swim.

There's no evidence of this whatsoever. Far more freedivers die every year than do scuba divers so that must not be true.

note: I don't believe any of the above, I'm just firing back your own arguments about pony bottles reframed as freediving so you can see how they look, but if you want to argue about evidence and pony bottles, you ought to argue about the evidence that freedivers can do a cesa better than the average scuba diver.