How deep have you gone on air?

[currier]

There are many accounts of narcossis in this thread - others tell that they don't feel the effects as much ...

I have questions regarding memory loss:

I don't know much about it (since I don't dive that deep ...), but I understand that some divers lose memory
as shallow as 55m - 60m on air?

Can some members give some information regarding memory at depth and / or personal accounts?

 

[DevonDiver]

Of course, you haven't been real deep till you have heard the WAH WAH

I get a BEEP BEEP BEEP.

When I did my first deep air dive, I actually thought someone's dive computer was alarming... it wasn't. The noise was in my head.

It happens most times that I exceed 50m on air. I count it as my 'in-built' narc detector now.

 

[Eric Sedletzky]

150 feet at the mile buoy in Monterey for TDI deep air class. Very boring, nothing but gravel bottom with a few pieces of seaweed rolling around on the bottom. A little narc but manageable. The other two guys in the class however were a mess.
Haven't had a need to go that deep or deeper since, but would do it again if I could find the right buddy that was competent and wasn't anti deep air.

 

[BHB ScubaTroll]

There are many accounts of narcossis in this thread - others tell that they don't feel the effects as much ...

I have questions regarding memory loss:

I don't know much about it (since I don't dive that deep ...), but I understand that some divers lose memory
as shallow as 55m - 60m on air?

Can some members give some information regarding memory at depth and / or personal accounts?

Fair enough question and I am happy to answer it...

My son was going through his "AOW" course with an instructor I know, myself and another diver I trust with my life on several occasions.

We were diving Hudson Grotto, Fl. This is a large hole in the earth that provides for dark scenarios that mock some cave diving experiences. On the surface before decent, I commented to the group, "Notice our exit point. If anyone gets lost, simply head due north and level off at 20'. If you do that, you will end up at the 20' platform and know you are safe".

We descended to 121' to the base platform and followed leader lines to many of the boats, autos and fun sights sunk in the Grotto for divers... At one point my son's instructor made a move that was unexpected and silted out the bottom within seconds. I looked at my partner (someone I have dived with many times and trust), he gestured we move over the silt out and capture them on the other side of the silt... That made sense and we did just that... No one on the other side...

Scenario running through my head... A call to the ex-wife... I'm sorry, we haven't found your son yet... at this point, I followed every line and moved for every off-shoot. If the boy went in the direction we were following he would end up in a 190' trench and no understanding of direction...

We made our way back to the platform we started at. My buddy was looking at his dive computer and I was flashing my dive light at anything that might have looked human! Finally, my buddy looked at his computer and looked at me, I knew we needed to head up and acknowledged it... We did our 1/2 stop and we did our last stop at 15'. We were greeted at 15' by the instructor indicating that everything was OK and my son was OK...

That was 15 minutes of my life I honestly don't want to ever live again!

On the surface, my friend the instructor validated the fact that he silted out the area, and that he immediately grabbed my son's BC... they waited for things to settle, but because the plan was blown, they rose to 20' and headed due north until they ran into the platform, did their safety stop and exited the water... waiting for us to surface...

I count this as a "Task loading" narc. My son's safety was so important to me that my narc lead me in all different directions. Honestly, If I didn't trust my dive buddy with my life, I might have sent him up the line without me while I attempted to search for my son again. That is how narc'ed I was. My son and his instructor followed my instructions/directions if we got lost, yet I trusted no one (other than my dive buddy) who partially insisted I surface with him.

I hope that gives you an example of memory loss. I was the one to point out the easy exit, but I was the one in danger of being too narc'd to follow my own advice

 

[Rhone Man]

I have questions regarding memory loss:

I don't know much about it (since I don't dive that deep ...), but I understand that some divers lose memory
as shallow as 55m - 60m on air?

Can some members give some information regarding memory at depth and / or personal accounts?

I have experienced mild memory loss at around 180 fsw (55 msw). I went into a hold of a ship looking for something specific, and resurfaced saying that I had been unable to find it, but when I looked at the photos on my camera, lo - I had taken photos of it!

I also remember reading one of Gary Gentile's books where he described doing a dive to 280 fsw on air, and he described it as like watching an old black and white TV at 3am with static obscuring the screen. You had some recollection of what was going on, but it was hard to piece together.

 

[drbill]

I think it'd be more accurate to say that you were narc'd but that you had dived enough to build up a mental adaptation that allowed you to function narc'd at that depth. Humans are quite adaptable in terms of training our bodies and minds to function on autopilot ... but that adaptation doesn't change our physiology.

... Bob (Grateful Diver)

I think what was happening in these cases was that my body had developed a pretty good acclimitization to nitrogen in the system and that while I certainly was narced, it appeared to have "minimal" impact on my brain function during that time of intense (300-350 dives per year) and deep diving. I had no perceptual narrowing to speak of, was easily able to survey the terrain (with great visibility), locate subjects to film, frame them and follow them if they were moving.

Were I to do the same dives today, now that I'm diving less frequently and to about half that depth, I'd be narced out of my gourd. Believe me, I know the difference Bob. I've been noticeably narced at depths as shallow as 110 ft and my worst case of narcosis was on a dive to 151 ft about a year after I stopped doing those deep dives. On that dive I had difficulty focusing on the subjects I went down to film, and recognized I needed to ascend after a relatively short bottom time of a few minutes. These cases of very noticeable narcosis all occurred during periods of low dive frequency and relatively shallow maximum depths (say 100 ft).

 

[currier]

he described it as like watching an old black and white TV at 3am with static obscuring the screen. You had some recollection of what was going on, but it was hard to piece together.

Sounds a lot like 'one of those' nights ...

I went into a hold of a ship looking for something specific, and resurfaced saying that I had been unable to find it, but when I looked at the photos on my camera, lo - I had taken photos of it!

Despite the fact that the thought of 'forgetting' a dive sorta frightens me, I find this to be hilarious !!

Thanks CoolTech & Rhone Man for your feedback ...

I can't help but think that memory loss should be one of those things that is discussed more widely when convincing the inexperienced to deter from deep air dives ... if air (pp?O2?N??) causes one to forget the experience, is there any point to conducting the dive?

I'm looking forward to learn more on the subject ...

 

[CaboJim]

176 ft in Curacao, bounce dive....

 

[Tortuga68]

Over the last 3 years I've done about 50 dives that could, by some defintions (>40m/130'), be considered "deep air". About a dozen have been beyond 60m/200'. My deepest is 100m/328'. A few of my friends have been in the 105-115m (345-380') range. In case anyone is interested, the current official depth record for scuba on air is 155m/510' which I have no intention of going anywhere near

All my dives were decompression dives using backmount manifolded double AL80s with air, and stages of 50% and 100% O2 deco mixes, conducted in the Philippines (Puerto Galera) with nice warm (shorty wetsuit!) open water, good viz & experienced buddies. All dives below 80m/265' had similarly equipped support divers at shallower depths (typically 21-40m) and spare O2 on the boat. Anything deeper than 50m/165' was part of a series that included shallower 'workup' dives

Bottom times varied between 25 and 8 minutes - kept short to limit oxygen exposure - with a typical total dive time (including decompression) of around 40-50 minutes. Run times were cut using current versions of specialist deco software

The dives were mostly enjoyable & I have a pretty clear memory of memory of them all to this day. At different times I experienced various symptoms of narcosis, including euphoria, paranoia, auditory ('jungle drums') and visual hallucinations - although not directly related to depth, eg the 100m dive I didn't experience any of the above (which is not to say I wasn't narc'd because I was). On all dives I maintained enough cognitive capacity to be aware of things like time & depth, or to perform repetitively trained skills like valve shutdowns; however I had no equipment or other failures and could not say how I would have reacted to a situation that required lateral thinking

Public Service announcement: Diving air below 65m exceeds the maximum recommended partial pressure O2 of 1.6 (for decompression diving) and should only be considered by people who understand the implications of that, as well as oxygen toxicity and other risks, and using appropriate redundant technical gear that they have training & experience in using, with appropriate buddies & support. Even in the 40-65m range air should only be used in relatively benign conditions - cold water, low viz, hard overhead, strong current etc should all cause a rethink of your personal MOD for air

 

[BHB ScubaTroll]

Sounds a lot like 'one of those' nights ...



Despite the fact that the thought of 'forgetting' a dive sorta frightens me, I find this to be hilarious !!

Thanks CoolTech & Rhone Man for your feedback ...

I can't help but think that memory loss should be one of those things that is discussed more widely when convincing the inexperienced to deter from deep air dives ... if air (pp?O2?N??) causes one to forget the experience, is there any point to conducting the dive?

I'm looking forward to learn more on the subject ...

Well, think about it for a minute... You get a story that makes complete sense except for this absurd little part. Now, you find out that the absurd little part was actually the time you were NOT narc'd under water....