SeaHound
Contributor
I am planning to do my first few dives below 100 ft. This would be "task oriented" diving so I wanted to know how much of a factor is nitrogen narcossis at 130 feet? How can I avoid / minimize narcossis?
Avoiding narcossis
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diver 85
Contributor
Been to below 120 many times & yet to 'feel it'...I'm not sure of the answer, will be interesting to see responses........
At 40m-130ft I doubt you are going to be too narked to carry out tasks, they just might take a little while longer.
Only way to avoid / minimize narcossis is 'depending on the depth' to dive a Nitrox or Trimix blend to lessen the amount on N2 in the breathing gas.
Cheers
Chriso
Only way to avoid / minimize narcossis is 'depending on the depth' to dive a Nitrox or Trimix blend to lessen the amount on N2 in the breathing gas.
Cheers
Chriso
Diver Dennis
Contributor
It's different on different days. I'm not sure you can mitigate the effects but I have thumbed going deeper a couple of times over 100' because I felt too narced but have gone much deeper the next day without any problems. I still get narced but not to the same degree, at least in the way I feel. Everyone is different too, things like anxiety over doing your first deeper dive can give you an uneasy feeling. Never be afraid to stop going deeper if you don't feel right and don't worry about what anyone thinks about it, experienced divers will respect you for knowing your limits.
Avoiding narcossis----Since we still know little about it, it stands to reason we can do little to prevent it while breath compressed air at depth. Many variables,,,,but some evidence lends itself to asending at a slow rate, and building up to it via gradual depth increases, and doing deeper dives often in your diving. No concrete evidence to show the use of nitrox really wards effect....now trimix is a different story. Being positive and in good health and plenty of sleep and diving deep in warmer and clearer waters shows some positives. The one time I was narced for positive was on a chilly dark dive to 110ffw into an old missile silo.
Narcosis varies from day to day, person to person, and is also related to environmental conditions and workload.
Clinical tests indicate narcosis is detectable from about 15 m - even if it is not apparent to the person experiencing it.
Opinions vary and I am not up to date on this, but in the late 1980's when I was learning about this, and later teaching deep diving courses, narcosis was generally considered to have a significant effect at depths greater than approx 30 m/100 ft.
I would suggest that it is actually a danger sign if a diver does not feel any effects of narcosis . The effects are there and it then becomes a question of how well the diver compensates for these effects. If a diver does not notice narcosis then it is easier to overlook the potential problems and get into trouble, in my opinion. When I was still teaching, students who insisted they did not feel narked were invariably the ones who had the poorest scores doing objective tasks (for example simple maths questions etc).
Your mention of task loading implies an additional risk factor. A particular problem of narcosis is a tendency to fixate on one activity at the expense of other perhaps critical tasks. For example, a diver might be concentrating on bottom time and depth but forget to monitor remaining air. Careful planning may reduce this risk but not eliminate it.
Performing an additional task may add to this problem.
A euphoric and forgetful diver fixated on performing a task is an accident waiting to happen.
Personally, I do a lot of deco dives to between 30 and 50 m (100 to 180 ft) on air and deal with narcosis on a regular basis while taking underwater photographs. On occasion I also have to deal with currents, low viz and complex navigation, maybe cold water and a drysuit as well as bulky heavy camera housings etc, and if I am not diving solo, monitor a buddy/model as well.
If I am doing more complex deeper air dives, I have found it useful to work up to depths greater than 45 m over a period of days. I am sure I would survive if I just jumped in and did the dive - but doing useful work would be much more difficult and not being prepared can be expected to increase risk.
I also did a lot of deep dives before getting training - relevant training was not available at the time - and prior to that did a lot of my own research and developed experience gradually.
However these days I suggest a course would be useful together with getting as as much experience as possible working up to greater depths gradually.
Many would suggest that helium is essential for deeper dives and that air is inappropriate at depths greater than sportdiving limits.
I have actually seen people experience life threatening problems in as little as 30 m (100 ft) - eg divers who ran out of air or getting too low on air but still failing to ascend due to narcosis - they were not my buddies but I rescued them anyway.
So to answer your question, finally, narcosis at 130 feet may be significant enough to get you killed, especially if you are distracted by some task, but personal variation and environmental conditions make it difficult to give any real answer.
The best thing to do to minimize the risk is to get experience and the safest way to do that is to get appropriate training.
Equally important, divers should not be afraid to say no if the dive starts to feel too complex or outside their comfort zone.
Sorry if this sounds a bit too preachy - but it seems that you want some serious advice - I actually think everyone should be able to dive how they like as long as they take responsibility for their own actions - and for me part of the fun of diving is pushing limits from time to time so I can see that side of it as well.
Clinical tests indicate narcosis is detectable from about 15 m - even if it is not apparent to the person experiencing it.
Opinions vary and I am not up to date on this, but in the late 1980's when I was learning about this, and later teaching deep diving courses, narcosis was generally considered to have a significant effect at depths greater than approx 30 m/100 ft.
I would suggest that it is actually a danger sign if a diver does not feel any effects of narcosis . The effects are there and it then becomes a question of how well the diver compensates for these effects. If a diver does not notice narcosis then it is easier to overlook the potential problems and get into trouble, in my opinion. When I was still teaching, students who insisted they did not feel narked were invariably the ones who had the poorest scores doing objective tasks (for example simple maths questions etc).
Your mention of task loading implies an additional risk factor. A particular problem of narcosis is a tendency to fixate on one activity at the expense of other perhaps critical tasks. For example, a diver might be concentrating on bottom time and depth but forget to monitor remaining air. Careful planning may reduce this risk but not eliminate it.
Performing an additional task may add to this problem.
A euphoric and forgetful diver fixated on performing a task is an accident waiting to happen.
Personally, I do a lot of deco dives to between 30 and 50 m (100 to 180 ft) on air and deal with narcosis on a regular basis while taking underwater photographs. On occasion I also have to deal with currents, low viz and complex navigation, maybe cold water and a drysuit as well as bulky heavy camera housings etc, and if I am not diving solo, monitor a buddy/model as well.
If I am doing more complex deeper air dives, I have found it useful to work up to depths greater than 45 m over a period of days. I am sure I would survive if I just jumped in and did the dive - but doing useful work would be much more difficult and not being prepared can be expected to increase risk.
I also did a lot of deep dives before getting training - relevant training was not available at the time - and prior to that did a lot of my own research and developed experience gradually.
However these days I suggest a course would be useful together with getting as as much experience as possible working up to greater depths gradually.
Many would suggest that helium is essential for deeper dives and that air is inappropriate at depths greater than sportdiving limits.
I have actually seen people experience life threatening problems in as little as 30 m (100 ft) - eg divers who ran out of air or getting too low on air but still failing to ascend due to narcosis - they were not my buddies but I rescued them anyway.
So to answer your question, finally, narcosis at 130 feet may be significant enough to get you killed, especially if you are distracted by some task, but personal variation and environmental conditions make it difficult to give any real answer.
The best thing to do to minimize the risk is to get experience and the safest way to do that is to get appropriate training.
Equally important, divers should not be afraid to say no if the dive starts to feel too complex or outside their comfort zone.
Sorry if this sounds a bit too preachy - but it seems that you want some serious advice - I actually think everyone should be able to dive how they like as long as they take responsibility for their own actions - and for me part of the fun of diving is pushing limits from time to time so I can see that side of it as well.
brianstclair
Contributor
SeaHound:
What do you mean by "task oriented" diving? Are you referring to the purpose of the dives? Spearfishing or photography or something like that? Just curious.
Brian
I don't know if this is narcossis related but sometimes before my second dive, I start laughing at the random things and just having a stupid and good time on the boat I dive from. Sometimes it causes everybody on the boat to go crazy too where they're yelling at me to get in the water.
Minipinny
Registered
My OW instructor once mentioned to my class to drink plenty of wate. It helps to prevent DCS at least. something to think about if you are going to do a deep dive.
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