Confused about Narcosis...

[dkktsunami]

If you want to read something chilling about the decision to do a deep, complex dive on air, read Shadow Divers or The Last Dive.

Funny you should say that. I am picking up Shadow Divers tonigth when I pick my tanks up from being filled Thanks[/QUOTE]

An awesome read - you will enjoy that book. Also "Diving Into Darkness" and "The Last Dive". Have fun, be safe.

 

[bleeb]

Lots of useful comments in this thread, so far.

Some additional food for thought: There was an interesting post in another thread that I'm too lazy to dig up, but further broke down narcosis into a few subcategories. The ones I can remember go something like:
1) How much someone is actually impaired;
2) How much they feel impaired;
3) The depth at which they think they may become impaired;
4) How much they can work around being impaired.

 

[captain]

The fact is until fairly recently, the early 1990's trimix gas was used mainly in commercial and military diving. From the beginning of recreational diving in the late 1940's until the early 90's deep open water recreational dives were done on air. Were divers dying by the dozens then, obviously no. Did some die as a result of deep dives, yes ( greater than 100 feet but less than 175 feet). Were more dying on open water deep dives then, compared to now. Nothing I have seen says there were.
A lot of deep air diving is done by the spearfishermen here on the Gulf oil rigs and we have had very few incidents over the years compared to northeast wreck divers. The difference is no overhead penetration diving which greatly increases the risk when combined with narcosis..

 

[MXGratefulDiver]

The fact is until fairly recently, the early 1990's trimix gas was used mainly in commercial and military diving. From the beginning of recreational diving in the late 1940's until the early 90's deep open water recreational dives were done on air. Were divers dying by the dozens then, obviously no. Did some die as a result of deep dives, yes ( greater than 100 feet but less than 175 feet). Were more dying on open water deep dives then, compared to now. Nothing I have seen says there were.
A lot of deep air diving is done by the spearfishermen here on the Gulf oil rigs and we have had very few incidents over the years compared to northeast wreck divers. The difference is no overhead penetration diving which greatly increases the risk when combined with narcosis..

My dad used to go to the bar every night after work and drive home hammered too. Back then, lots of people did ... and I don't recall it was particularly frowned on. Heck, the cops used to pull him over and offer to give him a ride home.

Think that'd fly today? Times change ... sometimes for the better.

... Bob (Grateful Diver)

 

[captain]

My dad used to go to the bar every night after work and drive home hammered too. Back then, lots of people did ... and I don't recall it was particularly frowned on. Heck, the cops used to pull him over and offer to give him a ride home.

Think that'd fly today? Times change ... sometimes for the better.

... Bob (Grateful Diver)

Last time I checked there were no laws against diving air to any particular depth.

No so with drinking and driving.

When 21/35 becomes almost as cheap and as available as air without some required certification I won't hesitate to use it and so will a lot of other divers. Until that time comes I'll stick with air and do the dive.

 

[gcbryan]

Last time I checked there were no laws against diving air to any particular depth.

No so with drinking and driving.

When 21/35 becomes almost as cheap and as available as air without some required certification I won't hesitate to use it and so will a lot of other divers. Until that time comes I'll stick with air and do the dive.

This is a very good point that is not brought up enough. Some would say if you can't afford the helium/training/etc don't do the dive but that's a cavalier approach since the person offering the advice can afford the dive.

For people spending thousands and thousands of dollars the price of helium is irritating but little more. You have to remember that the entry cost of helium is very high and for many it's overkill.

If you want to go deeper for a short period of time in an OW environment and money is an issue at all then you aren't going to completely change your equipment...doubles, stages, cannister lights, years of expensive classes just to be able to put a little helium into the mix.

I don't know what Tech1 is but isn't it something like a limit of 150 fsw and 30 minutes of deco with one gas or something like that? May be wrong on this one. Look at all of the expense one would have to go through just to go to 150 fsw. Now if you want to go there and stay there (wreck) or any penetration then for sure you have to pay the price or don't do the dives. I say for sure...they are some who would feel otherwise actually. But to go down the occasional wall ...for many it's overkill and out of their expense range.

 

[captain]

This is a very good point that is not brought up enough. Some would say if you can't afford the helium/training/etc don't do the dive but that's a cavalier approach since the person offering the advice can afford the dive.

For people spending thousands and thousands of dollars the price of helium is irritating but little more. You have to remember that the entry cost of helium is very high and for many it's overkill.

If you want to go deeper for a short period of time in an OW environment and money is an issue at all then you aren't going to completely change your equipment...doubles, stages, cannister lights, years of expensive classes just to be able to put a little helium into the mix.

I don't know what Tech1 is but isn't it something like a limit of 150 fsw and 30 minutes of deco with one gas or something like that? May be wrong on this one. Look at all of the expense one would have to go through just to go to 150 fsw. Now if you want to go there and stay there (wreck) or any penetration then for sure you have to pay the price or don't do the dives. I say for sure...they are some who would feel otherwise actually. But to go down the occasional wall ...for many it's overkill and out of their expense range.

Exactly, everything has a cost to benefit ratio, even safety. A on a 200 foot, cold , low vis, overhead dive the cost benefit ratio of He vs air is pretty good. On a 150 foot open water, warm, high vis dive its not.

 

[HowardE]

I did a dive today where I was narced. It was a dive to 185 feet, in cold water with low viz. Not only was it low viz because of the water, but it was dark.

I was narced, but it was a goal oriented dive, where I had a clear mission, dive plan, and strong competent dive buddy.

Narcosis management is part of learning to dive deep. How we handle the narcosis is different among divers, and often times; the first time you are narced is scary. For some people... they would just assume use helium on a dive to 150 feet. For me... Air, or Even 25% Nitrox would be just fine.

 

[MXGratefulDiver]

Last time I checked there were no laws against diving air to any particular depth.

No so with drinking and driving.

When 21/35 becomes almost as cheap and as available as air without some required certification I won't hesitate to use it and so will a lot of other divers. Until that time comes I'll stick with air and do the dive.

I have no problem with you or anyone else diving deep on air .... as long as they recognize the additional risks and accept the potential consequences.

You're right ... it's not a good analogy. Drunk drivers kill others. The worst a narced diver is gonna do is injure or kill themselves. At best, they'll adapt to diving impaired. But to insist that they're not impaired simply isn't the reality.

... Bob (Grateful Diver)

 

[gcbryan]

I think, for the most part, no one is arguing that they aren't impaired. That's a false argument that the "I'm not functional at 100 fsw" crowd use a lot but I don't see many arguing that they aren't impaired (some do I suppose). Arguments always seem to be made using extremes from both sides of any issue. The reality isn't a "side". As they say, it is what it is.

I wouldn't use air and then stick my head in a wreck or a cave. In OW the effects are gradual and unlike drinking (an often used analogy) if a problem arises a drunk will be drunk throughout the entire problem while a diver can simply ascend a few feet and the narcosis is gone.

I think the argument (to the extent that there is one, as I think most people agree with the facts) is just one of balance or reasonableness. The martini law in some versions is having a drink on an empty stomach every 33 feet. This is ridiculous. I would say that actual nitrogen narcosis as opposed to adding in Co2, anxiety and everything else is more like a mixed drink on a full stomach starting at 100 fsw and having another one quickly every 50 feet.

You're quite impaired at 200 fsw and shouldn't be doing anything complicated at 150 fsw but you can deal with problems albeit slower and then ascend a few feet and in a minute you will be fine.

Lumping CO2 and anxiety in is not rational because even though you can't control the mixed drink effect every 50 feet (that's the reality) you can control anxiety (dive more) and the CO2 (don't work/swim hard at depth).

I think these are the facts and someone really thinking things through would come to these same conclusions regardless of whether you use air yourself or not (you being the proverbial you).

As was mentioned earlier, for some it has to be more of a cost/benefit ration as well.