i think lynne is right.

[BabyDuck]

i was thinking. it hurt, but i kept it up. anyway, i have come to the conclusion that i'm also narced at ginnie. i don't feel quite the same at little river - perhaps it's because of slightly less fighting to get in - so depth + effort. i'm not debilitated, but passive and more stupid than usual. slower on the uptake.

i won't say i won't go again without a mix cert, but it's on the list of things to do. soon.

anyone else have any bolts from the blue lately?

 

[PfcAJ]

Yup. I stopped diving 32% there. If I'm going to drive up there, pay 25 bucks to dive, and put all the effort in to diving that cave, I at least want to enjoy it.

I also notice that switching from trimix to nitrox makes me sloppy. My stage drops and pickups are slower, line work isn't as neat, and I'll do stupid stuff like misclip a boltsnap.

For me, trimix is worth the extra 20-30 bucks for caves in the 90-110ft range.

 

[Cave Diver]

I've felt a degree of narc at JB before, but think it was mostly brought on from CO2 retention. Working harder than usual, breathing heavy, possibly skip breathing. Normally I don't notice a narc at most of the Florida caves.

What brought your realization on?

 

[fdog]

...I'm always narced.

I didn't really know it, and it turns out I kind of count on it as a depth reference.

Recently I had to run a scooter down our Tahoe Benchmark test track. This track is at 36' of fresh water, with markers every 100' at a constant depth. I've done this at least 100 times before, so I know it really well. Usually I'm using 32%. The track is on the side of a slope that is about a 35 degree angle and fairly featureless except for a tree trunk or rock occasionally.

This time, I had to do a test in dubs, so I grabbed a set that had leftover 21/35, and schlepped this huge scooter into the water, and dubs and a stage. After I was all set up, I realized that I'd forgotten my BT. No biggie, this is shallow and NDL and I know what the depths are...so off I go.

When I saw a sunken log go by that I knew was at about 55' fw, I realized my "depth perception" was way whacked. I had no clue I was that deep. So I concentrated on the terrain really hard, followed the visual clues for track depth, and generally completed the run at about the depth of the track, puzzled all the way. After 2 laps I had it figured out - I was used to a subtle hint of narc as a depth reference. To test it out, I started breathing off the stage, an 80 of 32%. After about a minute (because I was really concentrating on it?) I could feel a subtle something, and my ability to judge depth "without looking" came back.

I found this fascinating that narc comes so early. I mean, I teach that narcosis is always there, but didn't truly believe it until this happened to me. I'd thought that it didn't really begin onset until 60' or something.

...It's not like I'm a person that gets hyper narced or anything. At 100' I'm as happy as the next guy, but usually seem to be less narced than most. <shrugs>


All the best, James

 

[LiteHedded]

Lynne IS right
I use 30/30 at all those caves

apparently there's some stigma about worrying about narcosis at those depths.
I did a dive there with 3030 in the stages and nitrox on my back and was blown away at the difference once we dropped the last stage bottle. when you start the dive on 32% you wont notice it nearly as much. but when you switch at depth, at least for me, it hit me hard.

 

[MXGratefulDiver]

I used to think I was narc'd at Ginnie ... and then I realized it was just incompetence ... :shocked2:

... Bob (Grateful Diver)

 

[cerich]

most fla cave is PERFECT for Helitrox... really.

If anybody is diving down there and wants to try a helitrox cave dive to help you decide let me know... You'll be amazed at how much detail you miss on air or plain jane nitrox

 

[boulderjohn]

I used to think I was narc'd at Ginnie ... and then I realized it was just incompetence ... :shocked2:

Actually, my thought progression was somewhat the opposite.

When I did my first cave training, all the caves were blown out, and only Ginnie was diveable, and only through the eye. Consequently, all my first cave dives were there. I made a lot of the usual stupid errors common to new learners, but a number of my problems were uncharacteristic in ways that only I would know. We would have very simple dive plans, of course, but I had trouble remembering them. I was far more clumsy than I could believe doing the simplest skills. I just didn't feel right.

In retrospect, yes, I had the incompetence typical of a new cave student, but I really do think some of it was related to narcosis.

Or maybe I just cannot bring myself to admit the truth.

 

[MXGratefulDiver]

... sometimes I think I should take my tongue outta my cheek ... but then again, last time I did that it was quickly replaced by my foot ...

... Bob (Grateful Diver)

 

[TSandM]

You know, I've had the "opportunity" (read filled tanks with mix and then wasn't able to do the planned dive, and had to go shallower) to dive 21/35 in the 70 foot range. It was striking to me, how cheerful I was. For me, at home in OW, narcosis is primarily a feeling of unease, just a nagging not-quite-right sensation. I hadn't realized it was present at 70 until I did a dive where it wasn't there at all.

I've said for years that I'm stupid the minute my head goes underwater. I have lots of skills dives where I couldn't remember the sequence of things we were supposed to do, or couldn't remember the steps, or otherwise got turned around in a way I simply DON'T do on land, where I'm generally a pretty quick study.

I'm a firm believer that the Martini rule is right. Narcosis starts at 1 foot underwater. People don't recognize it because they're waiting to feel "drunk", and that doesn't happen until you're much deeper.

Oh, and I thought the stupids at Ginnie were a big part CO2, too -- until I made exactly the same kind of utterly stupid error at 98 feet in no flow at all in Mexico. I looked at a tie-off in the permanent line and thought, "Wow, that's weird -- there's an arrow (pointing out, at least I checked THAT) and then the line's tied off, and then it's tied off AGAIN about eight inches higher up and a foot away, and then it turns abruptly right. I wonder why they did that? You don't usually see the line tied off in two places that close together like that . . . " I totally failed to remember that the arrow almost certainly marked a jump somewhere nearby, and didn't look for that jump. I also KNEW from the briefing that the line would T, and we were to take the right-hand turn, and seeing a right-angle turn to the right didn't jog my memory that that might be said T. I mean, I sat and LOOKED at the thing for probably thirty seconds, without processing what I was seeing properly at all. I swam past the T; Peter saw it, and called me back, and I turned the dive on stupid. No more 100 foot cave dives on Nitrox for this gal, not ANYWHERE!