Deep-Six Underwater Systems, Inc.
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Table of Contents

1 Pressure and Gases
2 The Face Mask
3 The Snorkel
4 The Fins
5 Weight Systems
6 The Knife
7 The Wetsuit
8 Pressure and Water
9 The Ear and Pressure
10 The Sinus and Pressure
11 The Stomach/Intestine and Pressure
12 The Lung and Pressure
13 Barotrauma caused by External Air Spaces
14 The Buoyancy Compesation Device (BCD)
15 The Scuba Cylinder
16 The Scuba Cylinder Valve
17 The Regulator
18 Density and the Diver
19 The 4 Gas Laws
20 Hand Signals
21 Carbon Monoxide Poisoning
22 Hyperventilation
23 Nitrogen Narcosis
24 Diver's Flags
25 Sound Underwater
26 Color Underwater
27 Decompression Sickness
28 Breathing Oxygen
29 Deep Diving
30 Thermoclines
31 Thunderstorms
32 Underwater Life
33 Open Water Dives
34 The Final Examination
35 The Environment
36 Advanced Course

23 - Nitrogen Narcosis

     Jacques Cousteau's book, The Silent World was written in the late 40's. Chapter Two is titled, "Rapture of the Deep." In 1943, Cousteau's friend, Frederic Dumas (known as "Didi") were trying to deep dive in the Mediterranean Sea. They were in 240 feet of water. Didi was to descend on a line to the greatest depth he could reach and then release his weight belt and tie it on the line from the ship to the bottom. On page 30 of The Silent World Didi describes the dive:

     "'The light does not change color as it usually does underneath a turbid surface. I cannot see clearly. Either the sun is going down quickly or my eyes are weak. I reached the hundred foot knot. My body doesn't feel weak by I keep panting. The damn rope doesn't hang straight. It slants off into yellow soup. It slants more and more. I'm anxious about that line, but I really feel wonderful. I have a queer feeling of the beatitude. I am drunk and carefree. My ears buzz and my mouth tastes bitter. The current staggers me as though I had to many drinks. "I forgotten Jacques and the people in the boats. My eyes are tired. I lower on down, trying to think about the bottom, but I can't. I'm going to sleep, but I can't fall asleep in such dizziness. There's a little light around me. I reach for the next knot and miss it. I reach again and tie my belt on it. Coming up is merry as a bubble. Liberated from weights I pull of the rope and bound. The drunken sensation vanishes. I'm sober and infuriated to have missed my goal. I pass Jacques and hurry on up. I am told I was down seven minutes.' Didi's belt was tied off two-hundred and ten feet down. This huisser attested it. No independent diver had been deeper. Yet Dumas's subjective impression was that he had been slightly under one hundred feet."

     This was the first widely read description of the intoxicating affect nitrogen has under pressure. The description, "Rapture of the Deep" now is known as, "Nitrogen Narcosis" or "Inert Gas Narcosis".

     There is a law among divers known as "Martini's Law." It states: Every 50' of seawater equals 1 dry martini on an empty stomach. Although it is a rough estimate, it would mean a diver at 200' is experiencing intoxication from pressurized nitrogen equal to 4 martinis!

     Many gases are intoxicating when mixed with 21% oxygen. It is pressure-dependent. Also, the more a gas dissolves in fat the more narcotic it is. Nitrous oxide has a narcotic affect at sea level, and that is why you get "drunk" in the dentist's chair. Xenon dissolves in fat over 20 times better than nitrogen . It is far more narcotic and has been used for anethesia. The gases neon and argon do not produce intoxication at 1 atmosphere but will do it under a pressure less than 100' of seawater, argon having more potential than neon. Nitrogen is less intoxicating than neon. Oxygen has a narcotic effect similar to nitrogen, so breathing nitrox does not change the outcome. Helium requires a very great pressure (over 1,000 feet) to produce euphoria. A gas's solubility in oil and its atomic/molecular weight are causative factors.

     If you dive deep you will get "narced" because of nitrogen narcosis. What happens to you depends on several factors. As with alcohol, the reaction is due to personality, body size, fat content, mood, breathing depth, activity, and what you are looking to do. If you are trying to get narced, have an elevated CO2 level, are deep, and active the narcosis will be pronounced. And, the narcotic affect may be more noticeable from one day to the next keeping all the variables the same. It seems the more a diver encounters nitrogen narcosis the better it is tolerated. Also, the amount of narcosis reaches a maximum state in about 5 minutes at any given depth.

     Reactions vary to this drunken state. One diver was trying to break a depth record. A safety diver was observing from about 200'. The diver was below 350'. The last thing the safety diver saw the other one do was to take his mouthpiece out and try to hand it to a passing fish. Then he sank into over 3000' of water. Photographers on the Andrea Doria (216' deep) took fully 1 minute to insert a flashbulb in the flashholder. Just as with booze, some divers get giddy, some get beligerant, some get crazy. When a person is met for the first time is it possible to predict how the will handle liquor? Is a diver able to predict what will happen when they get narced for the first time?

     To show the reader how variable the effects are, this author was in St. Lucia and planned to go to 200' with an agreeable buddy. The first day the bottom slope was not steep and it took a long time to go deep. At 141' I started to feel the effects of narcosis. I was lightheaded and had a slight buzz on. It was euphoric. I signaled my buddy to abort the dive so we turned around and slowly made our way to the surface. My buddy claimed to feel no intoxication. We decided to make the attempt again the next day. This time the slope was steeper so we could go deep quickly. At 184' I felt no narcotic effect. All of a sudden my buddy turned around and wanted to do a do-se-do with my arm. Needless to say we aborted the attempt to go deeper.

     If narcosis is encountered all the diver has to do is go up in the water a short distance, often as little as 10', and it will disappear without any trace or hangover. Remember, Dumas was "sober and infuriated."

Copyright Information about this text, DIVING WITH DEEP-SIX is as follows: Copyright 1996 - 2007 by George D. Campbell, III; President. All Rights Reserved. This file may be posted on Electronic Bulletin Boards for download, but may not be modified, printed for distribution, or used for any commercial purpose without the author's written permission. is using this material with the permission of Deep Six. The full version is available at:
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