Dark Narc or Why I don’t dive air to 100ft

[ligersandtions]

Thank you for this story. I have never experienced those feelings, so it's nice to know what kinds of things to look for (and hopefully have the mental capacity to tell myself it will be okay and that I can get out without bolting to the surface). For the deep portion of my AOW class, I was hoping to get narced so I would know how it feels, know what it's like to work through it, and know what it's like to feel the point where it subsides. Unfortunately, one of the guys in my class blew through 2/3 of his air before we even reached the bottom (it was a straight descent, no stopping on the way down), so we were down there for a couple moments before we booked it up, and he sucked through the instructor's pony and the DM's tank on her back.

I really appreciate stories like this because I can kind of experience it second-hand, and hopefully be prepared for when it happens to me. To date, I have not exceeded 85 feet, with the exception of our AOW class....until I find a reason to do so, I probably will not.

 

[MurkyRockDiver]

Two weeks ago I had an episode at 101 feet is fairly cool water of 43F. I was diving a 30% nitrox but had a head cold the previous week. I had taken some pseudoephedrine (sudafed) and blamed the hit on that.

As I hit 101 feet after a 4 min decent my heart and breathing rate increased by at least two times, I was unable to slow them down so I ascended and the effect worsended up to 70 feet. Once on the deck at 50 feet all was ok.

I have never had narcosis and dive to this depth on a fairly regular basis, there is some discussion on nitrox and pseudoephedrine being a CNS exciter so it might have been that as well.... who knows.

Scary all the same.

 

[fnfalman]

The only thing that I've learned out of my five deep dives to date is that the narced feelings are not always the same. I have learned from the dives is that to ignore your "feelings" and trust the instrument.

Like I said, I only have five deep dives to date and my experiences were thus:

a) First & second dives were too excited and sucked air too quick and only stayed at 110-ft and 90-ft for about five minutes before heading back up. I was too excited to feel narced. Too much andrenaline in the system, I guess.

b) Third dive went all the way down to 130-ft to check out a wreck and cruised at 110-ft for about fifteen minutes. One of the guys was using a 95-cuft tank, so we cut the dive short. Felt good and slightly loopy - I knew that I was narced.

c) Fourth dive went to 120 and cruised around that depth at the same wreck as b. Felt fine. No narc at all...until it's time to go up. Started to feel panicky at 90-ft. Wanted to bolt to the surface, wanted to go back down deeper, wanted to panic. I locked my eyes on my partner and checked the gauges and forced myself to understand that I had plenty of air and that I am indeed going up.

d) Fifth dive went down to 100-ft and felt funny and happy.

I prefer not to go deep, but sometimes there are lots of cool things to see past the 100-ft depth. Things like wrecks, purple hydro corals, weird anemones at oil rig legs.

 

[do it easy]

I agree with DIR-Atlanta. I think that O2 is more narcotic than N2. It's probably an unpopular school of thought, but nothing comes for free, especially underwater. Narcossis should be given just as much respect as DCS- both can ruin your day.

piikki- great story- you really convey the nuances and subtlties of the dark narc. I would further add that the dark narc can affect you even in shallow depths. If the vis is poor and you are task loaded or anxious or just not feeling 100%, it will catch up with you.

 

[DIR-Atlanta]

The only thing that I've learned out of my five deep dives to date is that the narced feelings are not always the same.

That is absolutely true - narcosis is a physiological thing, and can have different effects diver to diver, day to day, dive to dive. There is no way to predict what type of response you will have, so the "ounce of prevention" approach is best. Stay shallow to avoid narcosis, and if you choose to dive deep, make sure you are appropriately trained, and that you use the appropriate gas and equipment for the dive.

 

[RiverRat]

I would further add that the dark narc can affect you even in shallow depths. If the vis is poor and you are task loaded or anxious or just not feeling 100%, it will catch up with you.

I have to say I agree on the shallow depths as well. Some of the local diving I do in the lakes can get dark, real dark and cold. I'm sure at 20-25 ffw there is no true nitrogen narcosis going on, there just isn't enough pressure. But I think it's mainly anxiety induced from the lack of light (visual references etc.) and the cold. On some of those dives I just kept telling myself "ok don't swim into one of those submerged tree trunks or you'll get hung up, and after 5 seconds your buddy will be out of the 3 foot visual range" and you'll be done. Or "keep the knife close if you get hung up in monofilament line so you can cut yourself loose". I think some of these kinds of dives can actually be more dangerous than some of the tech diving I'm starting to get into. When me and my buddy do these dives now (we like to practice in these lakes it's great training for low vis, anti-silting etc.) we stay VERY close, so close it gets very annoying when our fin tips hit. If you were to then add in another 75 ffw, with some associated narcosis, well you can see now you've got some serious mental impairment going on. I think if I were feeling the way I did in this example, I would just ascend from where I was up to a shallower depth if there was no deco involved or some other reason to keep me deep.

 

[mike_556]

Thanks for the sobering read...

 

[UnderSeaBumbleBee]

Thanks for posting. The dark narc is never fun. It is amazing how when you get a little shallower that is just clicks off and for that matter how when you get a little deeper it can just hit you all of the sudden.

 

[dukenukem]

I concur, an excellent read. Fortunately, I have not experienced anything like this. However, I will be starting my advanced diving class in November....

 

[TSandM]

I'm a great believer in Martini's Law. I'm a very bright woman on the surface, but get me 30 feet underwater and I'm stupid, and I get stupider as I go further down. When I say stupid, I mean that I'll do things like forget parts of the dive plan (say we had a list of skills we were going to do, in the order we were going to do them) and that I've taken long periods of time to learn certain things, and made the same mistakes over and over again -- none of which is typical of me on the surface at all. (No matter what my husband says.) That's one of the reasons why I'm so conservative about my diving . . . I figure at virtually ANY depth, I'm a little impaired, and therefore I should really optimize everything I can, so that when that one thing goes wrong, it doesn't cascade into a bunch of things that I have to handle when my brain isn't working at capacity.