PADI Deep Diver course

[Scubaroo]

Funny, an old thread on oxygen narcosis just popped up

 

[TCDiver1]

Forget any possible narcotic effect, start worrying about O2 toxicity. Going off memory here, and that can be dangerous, i recall reading about this whole oxygen can cause narcosis issue somewhere. What i recall is that it is suspected to cause narcosis. I am not aware of any studies that have proven that it does. Would be interested in anything which discusses this issue. Especially any studies that have been done.

On the O2 toxicity issue, it's always been my understanding that oxygen partial pressures at or above 1.6 ata put the diver at serious risk of taking a CNS or (central nervous system) hit. Padi uses O2 pp max of 1.4 ata for their limits to be even more conservative. This coupled with total diver oxygen exposure are absolutely essential for safe enriched air (nitrox) diving. Some would agrue that these O2 pp limits are too low but i believe them to be good limits for recreational divers since this group is so diverse in age ,physical condition, and skill level.

 

[O-ring]

Funny, an old thread on oxygen narcosis just popped up

Sorry...just curious..

 

[sheck33]

Originally posted by sea nmf
It is interesting because they make you test your thinking power at 100'. But I didn't learn any skills to speak of to prevent narcosis. I have been to 140' max and did not notice any huge impairment. But everyone is different. And pre-dive conditions can change what you would normally feel.

I agree that an experienced buddy or two can take you down and see how you feel. They just have to only watch you and not do a pleasure dive of any kind. Do this two or three times (of course not in one day) and you will have an idea of how you do at depth.

You have to make sure your buddies are very experienced and that they don't get narc'd so they can assist you, if you need it.

If you think you would be more comfortable with "professionals", by all means take the class. It is still a good day diving!

The PADI Deep diver course is a waste of time and money. I did the course and learned absolutely nothing. You can not prevent narcosis by any means other than diving trimix. You are impaired at 140ft, and you better believe it. Please dont go to greater depths with buddies 'that dont get narced'!!! people that dont get narced on air DONT exist!! Deep air diving is a killer, dont dive deeper than 100 ft on air, anything beyond that and you should be breathing helium mixes. If anything, PADI's nitrox class might be a bit more useful, nitrox is meant to extend divetimes by reducing nitrogen uptake, it does not prevent narcosis, oxygen has been proven to be just as narcotic or even more so than nitrogen.

The reason most people say they dont feel narced at greater depth is because they are not challenged, as soon as you had to respond to an emergency you'd find out just how narced you are,
and being in an emergency at 150 ft is not a good place to find out. I have been to 185 feet on air and that was to stupidest dive i ever did, nothing happened so i am here to talk about it and tell people not to do that, i sure will never dive that deep on air ever again.

 

[O-ring]

oxygen has been proven to be just as narcotic or even more so than nitrogen

Curious where the proof is...do you have a link?

The PADI Deep diver course is a waste of time and money. I did the course and learned absolutely nothing.

Agreed...

 

[exnewwavedivers]

sheck33

I did the course and learned absolutely nothing. You can not prevent narcosis by any means other than diving trimix.

PADI Deep Diver course does not teach you to prevent nitrogen narcosis. BTW, do you dive trimix?

 

[sheck33]

Originally posted by O-ring


Curious where the proof is...do you have a link?


There isn't really exact values or numbers to determine the ratio of oxygen's narcotic effects, but several sources claim it to be about as narcotic as nitrogen, ie.: The Physiology and Medicine of Diving" by Peter Bennett and David Elliott, 4th edition, 1993, W.B.Saunders Company Ltd, London

I dont recal the pages i found it on but stated was that in experiment done with people under higer pressures switching from lower to higher oxygen concentrations little difference was found in impairment strongly suggesting O2 is just as narcotic.
I'll try to find the links.

Then again there are always researchers that claim the opposite is true. My choice of the word proof should maybe be replaced with 'experiments very strongly suggest that', i guess until we figure out WHY gases are narcotic we cant prove or disprove anything. This is a fascinating field of research

 

[sheck33]

Originally posted by newwavedivers
sheck33



PADI Deep Diver course does not teach you to prevent nitrogen narcosis. BTW, do you dive trimix?

I didnt claim that the PADI deep diver course teaches you to 'prevent' narcosis. The only way to never be narced is not to dive. I am about to start the GUE tech 1 course once i have my gear repaired, this course includes helium mix diving, but i havent done that just yet.

I'd just love to know what PADI is trying to accomplish with their
deep diver course. What i would like to see is them extending their peak performance bouyancy course a lot more because as it is you see a video, you get a speech from your instructor but little or no hands on stuff where you actually practice this stuff.

 

[O-ring]

This is a fascinating field of research

 

[Scubaroo]

Well in order to help me make a decision on the deep diver course, I went with a buddy and we did a 118' dive at Monastery Beach on Saturday, which went fine except that I got stung by two wasps after the dive! Turned a planned 5 dive weekend into a 1 dive afternoon.

We went to the north end of Monastery Beach in Carmel, which has a reputation for being an accessable deep shore dive. My buddy had been to these depths before, and we decided before the dive that we'd follow the edge of a kelp bed out to the canyon edge, and if everything seemed fine, drop down following the sloping canyon floor to 120'. The beach is on the edge of part of the Monterey Canyon, so it's kind of deep We got to 80', which is close to the lip of the canyon, and dropped down onto a boulder at 100', checked our gauges, gave each other the okay, and looked down to another rocky platform at about 120'. Couldn't see beyond that as the available light was rapidly running out. We dropped down to 118', levelled out just hovering above the rock, gave each other the okay, checked gauges, hung around for about a minute checking out some different invertebrates on the rocks at that depth, and then spent another 10 minutes slowly proceeding back up to the sand at about 60', and then slowly made our way back to shore, doing a 5 minute stop at 15'.

My main interest in this dive was to check out nitrogen narcosis, and see how it affected me, as I hadn't been to these depths before (see earlier post). I felt fine at 118', but couldn't help but feel as I ascended from 118' that I was becoming more clear-headed, which was strange, because I hadn't felt like I was affected to begin with. By 100' I felt perfectly fine. Anyway I wasn't a blubbering idiot at depth, and we were able to stick to our planned dive, without deciding to "just drop down another 10' or so". So I was happy with my first encounter with narcosis.

Anyway for now I'm deciding *not* to do the deep diver course, as most of my diving will still be less than 100'. It's just good to know that I wasn't badly affected by narcosis at a deeper depth, so I feel comfortable doing slightly shallower dives than that for now.

Still can't believe I got stung by wasps in the trees next to the beach, that's what I get for taking a "surface interval" on their bush I suppose!



Ben