Simulated dive in chamber

[pisoiu]

I two weeks I'll be riding the chamber with some friends, in a simulated dive on air, at 57 meters.
We will experience nitrogen narcosis. What kind of exercises do you propose to perform in order to assess how much are we affected by it?
Thank you.

 

[Diver0001]

At 57m in a chamber it doesn't matter what kind of exercises you thought of. You'll forget them anyway

I found narcosis MUCH easier to assess and identify in a chamber than in an actual diving situation. At that depth your voice will be distorted and there's a good chance that you'll find that a significant distraction in itself.

As for exercises, I don't think you'll need them to be able to assess the narcosis. In a dry air environment it becomes very clear (as it were). If I had to make a suggestion then I would suggest to just take a book and try reading a page or two. Reading is something you do every day and it's a good base line to compare with because you know already how it normally goes.

R..

 

[kensuf]

I've been able to demonstrate the effects of nitrogen narcosis to students by having them play tic-tac-toe in 30m of water. It doesn't take much...

 

[tbone1004]

there are lots of papers in the Rubicon archive on narcosis simulations in chambers conducted at Duke Hyperbarics. One of the common ones are simple four function math problems, games like tic tac toe, etc. If they all speak english you can give them the Wonderlic test, do it at the surface then again at depth and compare the scores. Give them the same exact test, but give them the first one the night before the dive, or do it the day after when they come in to check for bubbles so they don't really remember the questions

 

[shoredivr]

When a group of friends did this exercise in a chamber ride to 200ft we took a bucket of water and put various brands of dive computers in it. My task was to record the computer's readings in a notebook, on the way down and back up.

My handwriting which is usually terrible became very tiny and very legible. I was completely focused on this task in an obsessive way. I recall that the computers at 200ft were not in agreement as to the depth, I think there was a 15 foot discrepancy between the shallowest at 195' and the deepest which read 210'. Of course they all got bent on the way up, as they were recreational computers and the chamber operator was using DEICM Canadian navy tables.

If you try this make sure the dive computers stay submerged in the bucket or they will get wrecked.

*edit* I enjoyed seeing just how potted 200ft was for me.

 

[grf88]

Take in a tape recorder with you and then listen to it afterwards. A video camera would be even better but make sure it can take the pressure first.

 

[Akimbo]

…I found narcosis MUCH easier to assess and identify in a chamber than in an actual diving situation. At that depth your voice will be distorted and there's a good chance that you'll find that a significant distraction in itself.....

Yeah, usually a lot of giggling like school girls for the first half dozen chamber rides or so.

Take in a tape recorder with you and then listen to it afterwards. A video camera would be even better but make sure it can take the pressure first.

Neither is a good idea. Chamber operators will probably make you leave anything that can make a spark outside for fire safety. There’s a lot of Oxygen in there even without pure Oxygen treatments.

However, there are view ports you can video through from the outside and speakers so you can record audio communications. Besides, the videography will be better in the hands of someone who isn’t narc’ed.

 

[grf88]

Ooops!, I had forgotten that they would probably increase the O2 to accelerate deco from that depth.

 

[pisoiu]

I will take the video camera with me, it's a midland xtc280. It will stay in its submersible case, rated at 85 meters. I will try to put it somewhere in a fixed location, not leave it to be operated by someone.
Shoredvr, I am really curious why should the computer be in water? What possibly can break? I have an alladin pro, it is an older model, oil filled, and I also use a VR3.

 

[Akimbo]

Ooops!, I had forgotten that they would probably increase the O2 to accelerate deco from that depth.

Maybe, but even without using O2 to accelerate decompression there is a lot of oxygen in the atmosphere on air at 57M/187' than at the surface — like 5.66 x more or 1.39 ATA. You will usually see a warning something like the attached image near the chamber door to warn against various fire hazards.

A lot of hyperbaric chambers have exhalation regulators on their BIBS masks to dump O2 overboard so the chamber atmosphere isn’t contaminated. Here is one of many models on the market. BIBS = Build-In Breathing System

Avox 801238-01 Inhalator without 1st Stage Regulator Assembly without Microphone Assembly

Have fun, chambers are great teaching tools even for experienced divers.