Max. depth on Air

[dc4bs]

Falcon99 once bubbled...
I may be a newbie diver, but I still think 200 feet on air has got to be one of the dumbest things I have ever heard of.

You people are crazy.

I can't argue with you there. It's not something I ever plan to repeat.

On the flip side, I now recognize the effects of narcosis in myself much better. Before that dive I would have sworn I had never been narced. Looking back, now that I KNOW for sure how it feels, I know I was somewhat affected a few times before that but didn't recognize it at the time.
BUT, I'm also sure that's partly come about simply through more diving experiance as well...

 

[ElectricZombie]

perpet1 once bubbled...

To be honest air is safe to a depth of 210 and change.

:google:

 

[DA Aquamaster]

Falcon99 once bubbled...
I may be a newbie diver, but I still think 200 feet on air has got to be one of the dumbest things I have ever heard of.

You people are crazy.

It's something you really need to build up to. With frequent, progressively deeper dives and enough experience, narcosis is not as debilitating as many people make it out to be.

But it is also important to put it in perspective. A relatively normal dive to 200 ft in a soft overhead environment under clear, warm, tropical conditions where you are unlikely to face a serious mental challenge is one thing. Penetrating a north east wreck on air at 200 ft would be pretty stupid as it is pushing the limits just a bit too far.

 

[perpet1]

ElectricZombie once bubbled...


:google:

Context, my friend, is a wonderful thing....

the actual quote should have been....
--------------------------------------

" To be honest air is safe to a depth of 210 and change. I do not recommend diving beyond your limits BUT the mix you use should not be a factor for recreational diving where the accepted limit is 130' which is VERY safe on air. A lot of people throw out very tech specific info but if you are a recreational diver it is all noise."

---------------------------------------------

and yes, thchnically with air P02 is <1.6 at 210ft. I do recognize there are a host of other factors to deal with BUT the gas itself does not impose a toxicity problem as 1.6 is considered the safe limit for P02.


The general point was technical divers try to influence the thinking of people who are obviously not at that level. I believe that the spirit of the initial post was basicly...... how deep can you really go on air. I also make it VERY clear with other statements like

-------------------------------------------

"DIVE WITHIN YOUR LIMITS AND COMFORT LEVEL. If the air were unsafe, then as a recreational diver, you would have been made aware of it through your certifications. If you want to go beyond your recreational limits obtain the training to do so. There are certifications to go to 200' on just plain air "that you use to fill your car tires and dry suit with". If you are going to be going to be doing a lot of extended range diving by all means Trimix is the answer but it should have a real purpose."

_____________________________

that it is not wise to dive to such depths.

techno bable of trimix does not help in the general discussion. Call me negative....

have I stired it up enough yet?????


Pete
NAUI Instructor

 

[perpet1]

diverbrian once bubbled...


I don't use tri-mix yet. I can't afford the training and gear yet. This is why my limit for any kind of diving is still 130 ish. Like you suggest, I use nitrox mixes to minimize narcosis and extend bottom time. (As my previous post in this thread states)

I don't necessarily agree with your PO2 planning, but that is another issue. I was trained with and generally try to keep my average depth within a 1.4 PO2 as that is what is taught for cold water diving.

I would recommend removing the word average. By that logic you can use all the time you are < 1.4 (like the time getting to depth) to go against going >1.4. But you are correct that a limit of 1.4 is recommended for "particularly hard or cold dives"

Due to narcotic effects, I personally wouldn't dive below about 150 on air if I was trained. From what I know, if I were to plan a dive below 140', it would have to wait until I get Tri-Mix trained in a couple of years. I like to have a safety margin. I have spoken to "old timers" among our instructors at the shop and they described the level of narcosis that kicked in below 150' on air as no fun.

But, this is not an issue of "tech" divers wearing a badge of honor. This is a commonly asked question asked me by non-divers (although they don't know about nitrox, so the "on air" part never seems to come up). It is also a question of curiousity among divers. Yes, "tech divers" do have to have better training for this. Many of them seem to choose Tri-Mix for a reason. Many of them choose air for a reason as well. It is nice to hear those reasons once in a while.

Good point! I am not against tech divers in fact i do it myself but it is something that has a time and a place.

If you are discribing to a layman how deep you can go the answer is rather simple. Lets face it they will not understand the "why" and "how to's" anyway.

Lets find another thread to discuss the role tech diving plays.

Pete

 

[Coogeeman]

In perfect conditions, with two spare tanks just in case, I went doen to 210ft......I wanted to go deeper but a school of Blue Fin Tuna went by being chased by a Hammerhead and my camera casing started to crack.

Would I do it again? maybe not..then again....

Coogeeman

 

[diverbrian]

perpet1 once bubbled...

I would recommend removing the word average. By that logic you can use all the time you are < 1.4 (like the time getting to depth) to go against going >1.4. But you are correct that a limit of 1.4 is recommended for "particularly hard or cold dives"


Pete

I knew what I meant to say, but you are correct in that I said it wrong. I try to plan so that if I drop a light, have to help my buddy who finds himself on the bottom, or some such thing, I will be no deeper than 1.5. The plan is for 1.4. Obviously, the keeping no more than 1.5 under me will be impossible at times. Then "common sense" comes into play. Let's face it, a quick "bounce" to 1.5 or 1.6 most likely won't send me into convulsions. Staying down there may cause me some problems that I would rather not deal with.

As we all say, Plan a safe dive, Dive your plan. Thanks for the correction.

 

[Grumman581]

I've been to 190 ffw (spring in FL) and 180 fsw (Coz)... It's been too many years since the cave dive, so I don't remember how narced I was... It was a quick bounce dive, so I probably didn't have much time to get narced... In Coz, I noticed the start of the narcosis at around 165 ft... A little more fixation on my depth gauge... By 180 ft, I didn't realize initially that I was breathing out of one reg and looking at the pressure gauge for the other tank...

 

[perpet1]

Coogeeman once bubbled...
In perfect conditions, with two spare tanks just in case, I went doen to 210ft......I wanted to go deeper but a school of Blue Fin Tuna went by being chased by a Hammerhead and my camera casing started to crack.

Would I do it again? maybe not..then again....

Coogeeman

expensive dive if you had to replace your camera.... Was it worth it?

 

[DrSteve]

recreational diving to 50m. But they do teach that air diving is safe to 70m which is the absolute cut off (around 210 feet).

So nitrox increases bottom time, does it decrease the incidence of narcs or is that about even compared with air?