OK to Bounce Dive to 220 Fsw as...

[gcbryan]

It's not a good way to teach people how to dive and it's not a good message to send to new divers and it's not the message an instructor should be sending.

However, the other comments are the usual ones and aren't quite accurate or on point in my view.

The diving drunk analogy is a little too dramatic and those who are sure they would kill themselves at 200 fsw are usually those who have just stated that they have little experience working up to those depths. So they don't really know that they are really narcosis sensitive.

More than likely they are just affected by it to the degree that everyone else is. They just chose not to get more experience (probably a very good decision) but others have and have faired OK as well. It's easy to point to those who didn't do it the gradual way and who paid the price but those who don't do any activity the right way often pay the price.

Again, my comments are more to take some of the drama out of these discussions or to be more accurate (in my opinion of course) rather than to be a cheerleader for diving deep on air. Pointing to those who died doing something stupid really is not a valid argument.

 

[BDSC]

This is more a testament to the reliability of gear than the inherent safety of doing such a dive. It always boils down to how much risk one is willing to take. If you're willing to risk that everything will go right ... as it usually does ... then you will be fine.

One of the things that makes diving a safe sport/hobby to me is, in fact, the reliability of todays dive equipment. So far, (knock on wood) I have never had one single problem with any piece of dive equipment while on a dive. I do have my equipment serviced regularly. But like you said, it's how much risk is a person willing to take. I have no problem with risking everything will go right because in over 600 dives it has. Of course I realize the very next dive something could go wrong. But what are the chances that when/if something does go wrong, it will happen on that particular dive. To me, the chances are so remote that I have no problem doing a 140ft dive on a single tank of air.

Any of those things could cause you to run your tank empty before surfacing. Of course, you can always rely on a dive guide to bail you out ... but that's the definition of a "trust me" dive.

In a way, aren't all buddy dives a sort of "trust me" dives? Aren't you trusting that your buddy will be there for you if you need him? Whether it's 50 - 60 ft. or 130 -140 ft., you're putting a certain amount of trust in your buddy to be able to bail you/anyone out if needed. I would suppose solo diving is the ultimate trust in yourself diving.

 

[lamont]

I am in no means trying to start an argument but I know several people that dove 200+' on air in the 90's and are still here (they are all on trimix now). I'm not starting the deep air thread up again I'm just saying that is how it was done for a really long time...

..and now there's better gear, training and gas...

and only a few people died...

...only a few too many...

and narcosis wasn't the cause in most of those deaths.

...i'll bet it was a contributory factor.

...it is also never the alcohol that kills anyone drunk-driving, its the blunt force trauma of the accident...

I've been to 190' and narcosis is defiantly there but to say that narcosis at 200' incapacitates you and will kill you is just wrong. You are very correct saying that low vis, cold dives make those conditions much worse.

when you consider recreational divers with little experience, who are already typically overwhelmed by just breathing off a regulator underwater, going to 200+ feet, i think its very likely that they'll get overwhelmed by narcosis and that is exactly what occurred in the 2006 incident here (the guy who died actually died saving an inexperienced diver whose brain vapor-locked due to the narcosis).

 

[scubadada]

That is indeed, a frightening story for a whole load of reasons including training, experience, planning, and equipment. Clearly, environmental factors may also play a roll. A night dive in very cold water with current and poor visibilty may have a different outcome than a day dive in warm water with no current and good visibility.

Craig

Or all those conditions just breed complacency, and the narcosis at 200 feet incapacitates you anyway and you wind up just as dead...

The cold, dark, low viz conditions make this kind of diving riskier, but that doesn't mean that 200 foot bounce dives without those conditions is safe or sane...

I clearly never said it was safe. It's all relative, a dive like this can be dangerous, very dangerous, or even foolhardy depending on all of the variables involved.

I have 122 dives over 100 feet but only 10 over 130 feet. My maximum depth of 153 feet was with a pony and a very good buddy with a pony under the ideal conditions I stated above on a site we had dived several times before. We considered the dive relatively dangerous, planned it carefully and executed it according to plan. I'd have to have a very good reason to diver deeper than this and would have to accept the inherent risk prior to planning such a dive.

Good diving, Craig

 

[gr8fuldiverNC]

I understand partial pressure isn't really the issue, since hyperbaric chambers help people heal and they are at 2.0

My question was geared toward narcosis and ascent rates
and that they would be making a fast decent to hit 220.

The instructor that mentioned this is an SSI instructor and I see problems with anyone diving outside their bounds just to hit a depth mark. Narcosis would be an increased risk with the rapid decent and ascent –

More thoughts?

Yikes, an example of know just enough to be dangerous. First off, hyperbaric treatments are closer to 3 atm for DCI (pure O2 at 60 feet on a schedule 6 if I remember right). Second, oxtox works differently in the water than in the air, you are much more likely to tox out underwater, and at lower pp. Third, toxing out while lying on a table under a doctors supervision is not a problem, passing out underwater is, in that the tox hit wont hurt you, but the drowning bit might. Plus physical exertion (ie diving vs laying down) is a factor as well.

And then theres the narcosis... dont know about you, but Im narced outta my brain about 170. No problem tho, until theres a problem....

 

[peterbj7]

More than likely they are just affected by [narcosis] to the degree that everyone else is

The degree to which people are affected by nitrogen narcosis varies enormously from person to person, and indeed from time to time for the same person. I felt narced on a dive a couple of years ago, but otherwise not for quite a few years. That's probably largely because I'm accustomed to making fairly deep dives at relatively high pN2. But there is no norm for (subjective) narcosis.

 

[mksmith713]

There's nothing wrong with a bounce profile even though it gets a lot of comments on Scubaboard. Multiple bounces is another matter. It is possible to bounce (for whatever reason) and still continue to have a long (shallow) dive before getting out of the water.

The reason for the bounce is not particularly important although certain groups commonly respond to the contrary (with virtually identical wording).

I would think....as long as you have enough juice in your tank......a long shallow dive following a bounce (both in the same dive) would be the best thing to do.
Call it a long deco stop if you will.

 

[mksmith713]

PADI AOW has a depth limit of 100', not 130'. 130' requires the additional couse of deep diver.
Ask these new AOW divers if they are organ donors, if you feel they are likely to go on such a foolish endevour.

I don't know about you but we dived to 130 fsw duringall but one of our AOW dives.
The dive charter I dive with now requires AOW or greater and we consistantly dive deeper than 110 fsw.
Of course, they also require nitrox certs.
But they've never asked for Deep Diver cert.

 

[CompuDude]

I don't know about you but we dived to 130 fsw duringall but one of our AOW dives.
The dive charter I dive with now requires AOW or greater and we consistantly dive deeper than 110 fsw.
Of course, they also require nitrox certs.
But they've never asked for Deep Diver cert.

If that was a PADI course, your instructors violated standards, plain and simple.

100' is MAX depth allowed for AOW courses. (What you do afterwards is out of their control, but during the class, PADI's standards are very clear on this.)

 

[GrandpaScuba]

Isn't "Advanced Diver" still a recreational certification? Wouldn't the accepted depth limit for recreational diving still be 130' ??

Even a bounce dive to 220 would require decompression. This seems a tad bit beyond the level for "advanced diver"??

YES and YES