Question Ever experienced Nitrogen Narcosis?

[NothingClever]

From the US Navy Diving Manual (01 Dec 18).

The completion of the last sentence is: “…as deep as 180-200 fsw, but novices and susceptible individuals should remain at shallower depths or dive with helium-oxygen mixtures.”

I know for myself at 40m/133fsw under normal thermal and work conditions, I don’t suffer major impairment but I have to concentrate and make deliberate mental notes to remember the sequence of events, especially if going in and out of a wreck.

I know my primary symptom deeper than that and have specific safeguards to stay safe but that’s beyond the scope of the Basic Scuba sub-forum.

 

[Gone for diving]

I am a firm believer that you want to know what it feels like for yourself, under controlled conditions. Knowing the symptoms will help you in the future to be prepared. And not worry about it,
Normally being narced is not a big deal.

But there is a 110 ft wreck I have done tons of times on air ....
One time I was busy helping others and was last one off the boat. Kinda hurrying up to get in the water, did a quick decent,
And wasn't a problem till about 5 minutes into the dive... hit me like a wall. (Co2 build up and quick decent is my assessment )
It's not scary... it's like being in a dream with a small headache, but i still have control. But tend to get very focused, and I tend to check spg, and equipment alot and make sure everything is work properly.
go up a 10ft and its alot better.
Don't think is something to be afraid of.
Just to be aware of it, that's all.

 

[Jonn]

I’ve only had positive encounters with the Rapture of the Deep. A calming feeling of well-being is not necessarily a bad thing. Situational awareness does tend to suffer though, it’s easy to get over focused on routine chores like checking the gauges. Experience is the key here: do your first few deep dives in controlled circumstances with an attentive buddy and pay close attention to how you feel. If you’re above 100’ it’s no issue at all unless you’re particularly susceptible.

 

[TrimixToo]

One weekend I was short on time, so I didn't mix and dove on air. The planned dive was only a few minutes, to 160' or so, to attach a float to something. It turned out the bottom sloped sharply and the thing I was going to attach the float to was actually at 180'. With my Extended Range cert, that's actually supposed to be OK (hah!). The dive went OK. I felt fine, surprised that I had no real impairment that deep on air, and tied a beautiful knot, or so I thought. The following week I went back on mix. It's a miracle the float stayed attached! I managed to undo the rat's nest, retied the knot, and went on my way a bit wiser.

My son once got incredibly narced at only 75'. He kept grabbing my arm and pointing at the boring, featureless freshwater bottom. When we got up, he asked, "Didn't you see all the Mini Coopers?" Uh...no, son, 'cause they're not there. It never happened again, even when he dove much deeper later on.

For what it's worth, I normally descend as fast as possible consistent with not crashing into the bottom (or wreck, or whatever).

 

[Esprise Me]

The deepest I've gone in a cave on air is around 150, and I knew I was narked and my buddy asked me to please use mix next time. I did, and I made a rule for myself, no cave (or deep wreck penetration) dives past 130-140 without using trimix.

I never thought about it like that, but it makes a lot of sense to have a more conservative depth limit for overhead environments vs open water when diving on air. I've only done brief swim-throughs on the Yukon (100 feet to the sea floor, parts of it closer to 60 ft) and shallow caverns, and I've done open water dives down to 130 feet and stayed sharp. But I also know I could still get narced at depths where I've been fine before, and having to find my way out of something before I can ascend could make things a lot worse. Thanks for sharing that!

 

[Barefoot_Lawyer]

Did everybody go down and do math problems at 110’ for their AOW like I did? I didn’t feel narc’d (maybe slightly euphoric?) but it took me 2x as long to solve 10 simple math problems as it did on the surface and I got one wrong.

 

[inquis]

Narcosis can come on very quickly and rapidly.

I'd second this. For me the line is very noticeable. Well, at least "a" line is noticeable. I'm probably somewhat impaired before that, but there is a definite depth where I'm like "whew!" and 10 ft shallower was like "eh".

 

[inquis]

I am a firm believer that you want to know what it feels like for yourself, under controlled conditions.

+1. Additionally, if you are able to switch / gas share with someone with helium at that depth as a test, you might find it interesting.

 

[Belzelbub]

Did everybody go down and do math problems at 110’ for their AOW like I did? I didn’t feel narc’d (maybe slightly euphoric?) but it took me 2x as long to solve 10 simple math problems as it did on the surface and I got one wrong.

I did. Didn’t feel narc’d at all. I was fairly quick on the math problems. Maybe a little slower than normal, but not 2X. I was diving EAN32, which probably helped some.

 

[Blackcrusader]

Did everybody go down and do math problems at 110’ for their AOW like I did? I didn’t feel narc’d (maybe slightly euphoric?) but it took me 2x as long to solve 10 simple math problems as it did on the surface and I got one wrong.

When I did the math at 40m I could not complete it all. But it is not important that you do so. What was important was that I maintained depth and did not drift deeper and paid attention to my NDL and signaled to ascend with a few minutes of NDL time remaining. This is what my instructor was looking for. He had other divers try to stay and finish the math instead of watching their depth and NDL they let themselves get distracted and lost situational awareness.