Is Deep Air / Light Deco (bounce?) Discussible on ScubaBoard?

[MauiScubaSteve]

Technical deep air dive, what is wrong with it?

....

We normally dive to around 54m for 25 mins BT and using 50 and 100 for deco. Total dive time is around 60 mins.
We will add He if we are penetrating wrecks over 50m deep in OW.

Nothing IMHO.

The initial disagreements concerned deep air 'bounce' diving within the recreational community.
i.e. non-technically trained divers who might choose to 'bounce' down to depths beyond 40m, using air and/or a single cylinder.

....

However, without that training and knowledge, a diver may make extremely imprudent decision, based upon a lack of knowledge of, or respect for, risks that they fail to comprehend.

So, full disclosure for the OP w/ regards to deep air is that my deepest "planned" dive was not planned to a specific depth, other than "somewhere in the neighborhood" of how deep I had been before. I didn't make it as deep as I was once forced to go at work.

I went 146' deep that one work dive, to stop the descent of a gray reef shark picture taking tourist diver (155'). He knew that my "job" was to keep him from going too deep. We went quickly up to the rest of the group at 80' and that multilevel dive ended up lasting over 45 minutes, with a normal 3 minute SS indicated on my Suunto. Those were single AL80's and neither of us would win any kind of air consumption contests.

I went 138' deep that "planned" deep dive, to take pictures of gray reef shark. I moved fairly quickly up to 80' and that multilevel dive lasted exactly 60 minutes, with perhaps a 4 minute stop indicated on the Suunto. That dive was a single AL100.

http://www.scubaboard.com/forums/hawaii-ohana/243718-molokini-kayak-dive.html

The following quotes aptly describe my two deep air dives, but my point in this post is that these two dives were not technical dives; IMHO they were recreational dives. And IMHO I'm a recreational solo diver, not a technical solo diver.

Since my conservative old Suunto Viper lets me plan NDL dives down to 150' deep, I'm kind of leaning towards a 50 m "recreational" depth limit.

When people beat their chests and brag about going all the way down to 150 feet (10 feet more than the real limit of recreational diving) for a few minutes, I have to admit that I do snicker a little.

The sport diving limit has always been 160' (on-air), but some people don't know enough to come in from out of the rain at that depth. To those people I would recommend that they don't dive that deep using air. It's common sense....

It seems it is even hard to define the recreational limit; good luck with "bounce dive."

 

[knowone]

What are those freediving fins you bought earlier this year
DUDE

 

[dumpsterDiver]

Well if there is no consensus on what is a technical dive, we definitely are not going to agree on what a bounce dive is.

For me, a technical dive is one where deco is required or where the depth is past 130 feet.
For me, a bounce dive is a short dive that keeps deco "short" or avoids it.

I used to do maybe 4 "bounce" spearfishing dives per day to around 180/185 feet. We used single 80 tanks (and a pony) and would often have some oxygen hanging from the boat to clean up.

Dive times were on the order of 8-9 minutes usually and were done solo. Usually the last few dives required some deco.

I had some pretty significant issues with headaches, presumably because of the depth and exertion of chasing fish and the practce of holding your breath for a pretty long time while stalking fish. This is a perfect recipe for taking a CO2 hit.

After many dives, it became clear that an 80 cylinder was more than enough air for these dives and it made little sense to try to conserve air. I discovered that if air consumption was not an issue, I could significantly reduce or eliminate headaches by breathing faster and harder than my body told me was necessary. This was initiated on descent and was continued during the dive (except when breathing was stopped to stalk fish). I'm not talking about ridiculous hyper ventilation, but rather a concerted effort to just breath a little deeper and a little faster than felt necessary.

Also, these dives were conducted over a full day, with surface intervals of around 2 hours. We also started to do some deep stops at around 75 feet or so, for maybe 2 minutes. This seemed to reduce fatigue.

It is probably less dangerous to do several short spearfishing dives per day and avoid any significant deco, than to do one or two long, deep dive and accumulate a lot of deco, especially when there is a potential for sharks coming around the speared fish during deco.

I think it is worthwhile to talk about these kinds of deep air bounce dives in order to give people the proper perspective. It IS dangerous and you can get hurt.

But if a new diver is paired up with a few divers who have been diving like this for so long that they make it look "easy", I think a beginner might be more susceptible to trying to hang with the other divers if they have not been presented with a well rounded idea of how it can go bad and how much narcosis can play into the complexity. "deep air" threads, allow people to explain just how dangerous this type of diving is and it has more value than simply saying "only do what your PADI instructor told you to do".

It is interesting to note that I know pretty many deep air divers and they think nothing of diving 180 feet. I also know a few EXTREMELY experienced commercial lobster divers who dive more days than not (3-4 tanks per day) in 80 to 120 feet (for many years) and some of them say the narcosis past 150 totally freaks them out and they just don't do deep dives and think it is too dangerous and stupid. It provides further support for my opinion that some people are much better at handling narcosis, regardless of how good a diver they are.

 

[DevonDiver]

For me, a recreational dive is one that permits direct ascent to the surface. A technical dive involves a ceiling; whether rock, metal or deco. If the surface is not obtainable, beyond the divers' capacity to ascend on a single breath, then it changes the game drastically.

I used to define a technical dive in respect of mixed-gas use, but normoxic trimix really screws up the simplicity of that view. However, one critical aspect remains; that, for me, determine a technical dive - that being the use of gasses on a dive that are not breathable at all planned depths of that dive.

Narcosis is an issue. I think I'd also support a definition that presented a reasonable limit based on nitrogen partial pressure.

 

[MauiScubaSteve]

What are those freediving fins you bought earlier this year
DUDE

Another reason "my" diving just can not be described as tech ...

[c]

[/c]

One of those fins chose to jump overboard from that boat, and a few months later I found a replacement pair on ebay; $72 shipped.

 

[Adobo]

Technical deep air dive, what is wrong with it?
Completed IANTD Deep Air and Adv Nitrox in 98 and Technical EAN a yr later.
In those day the Technical EAN was 60m max and I believe it had been changed to 50 odd m now.
We normally dive to around 54m for 25 mins BT and using 50 and 100 for deco. Total dive time is around 60 mins.
We will add He if we are penetrating wrecks over 50m deep in OW.

Maybe the better question is, what are the advantages and disadvantages of doing a dive to 54 meters on air vs. some trimix blend?

 

[Adobo]

No, due to the number of people who come on and instantly slate anyone who suggests the idea. If anything these threads actively discourage people to do deep air dives.

Those who have a genuine active interest in deep air should, in theory, be using the threads to gather information and experiences from other divers so they can plan their dives with the most information available to them.

Whether or not the general SB user looks at these threads and thinks, "hey, yeah that sounds cool, I'm going to try that" is in a way irrelevant. If people don't wish to do the research or training through any aspect of their diving is upon their head.

As for 'light deco' (read: deco), I believe it is something BSAC teach from a basic level in a recreational environment, and there are other agencies who teach deeper air anyway (PSAI?). Not all agencies necessarily agree to air after 40m being dangerous and not all agencies agree that decompression dives are technical dives.

Personally the 'average' recreational diver should perhaps be prepared with more PP02 knowledge, more in depth information in to N2 narcosis and understand more about 02 exposure/CNS/OTUs.



Yes these discussion should be happening openly to either prevent, assist or provide further knowledge to those who wish to look at deep air dives.

However, I am a firm believer there are people out there discussing these things (internet divers) or people out there getting on with it - and that applies to all aspects of recreational and technical diving.

Just my 2 worthless pence.

Is the internet really the place for people who don't know better to gather information on how to do deep air dives?

I have no qualms with divers who have taken training on how to do deeper dives discussing their experiences and what they feel are working well and not working well for them. At least these folks have the context of what it takes to properly execute the dives in both "best case scenarios" and "predictable-dive is going south" scenarios. These types of divers can at least anticipate the consequences of modifying gear/techniques/procedures.

I'm okay with these divers even sharing this information to those who don't have the training/knowledge for as long as its clear that trying to piece together how to do deep dives in the internet is not a substitute for proper training under a qualified instructor.

At some point though, I would think that we need to recognize that people who survive deep diving despite their lack of training, knowledge and appropriate gear are probably not the best people to give advice on this topic. Just as I think we would all agree that a diver who survives overhead penetration dives despite their lack of training, knowledge and appropriate gear are not the best people to give advice on cave diving.

And that is my 2 centavos worth.

 

[MauiScubaSteve]

For me, a recreational dive is one that permits direct ascent to the surface. A technical dive involves a ceiling; whether rock, metal or deco. If the surface is not obtainable, beyond the divers' capacity to ascend on a single breath, then it changes the game drastically.

I used to define a technical dive in respect of mixed-gas use, but normoxic trimix really screws up the simplicity of that view. However, one critical aspect remains; that, for me, determine a technical dive - that being the use of gasses on a dive that are not breathable at all planned depths of that dive.

IIRC, Thal once described one part of the Scientific Diver cert system as the ability to free ascend from your certified depth; to get a 50 m cert one must free ascend from 50 m, and probably not just once.

I have free dived to ~102', twice, and I still make 75' without much thought or effort. With EAN25 and using "my" nitrox training (1.6/1.8) my computer shows a max "working" depth of 178', and I think a half breath at 178' is significantly more than a full breath at the surface.

If I were to make a planned 25 dive to 175', with my 120 cft, I would have my 30cf pony full of 32. Catastrophic failure during the couple minutes at max depth my plan would be to boogie on up, and the science I have read does not indicate that I would Otox on the first or second breath, even at more than 1.8.

 

[lamont]

Is the internet really the place for people who don't know better to gather information on how to do deep air dives?

The internet seems to promote a race to the bottom of stupidity everywhere else, so why not here?

I really miss GI3 sometimes...

 

[Sat Diver]

Diving air deep is like driving drunk fast. It can be thrilling, but you are more than likely to wind up in trouble. There was a time when there was no option. But now there is - helium.
So why not use it ?