Dan_P
Contributor
Sorry your story sounds a bit strange to me.
A Co2 narcosis? Do you mean a N2? If it realy is CO2 intoxication check your air supplier. The amount of co2 in compressed air is limited normally and not available in percentages being dangerous.
8ft or 2,5 mtr vis is the norm in many parts of the world. Define cold water? When I’m back home the water temp will be down to 7/8dgr C kast winter we dove 4dgr C water and sub zero temp above.
If your computer fails you will surface. How to keep to the 15ft safety stop. Your serious about it otherwise you won’t do it after being passed out and “filled” up on water during a dive. No time and no depth availabe when your comp brakes down.
Even a 2nd stage cut back to nearly closed should give more than enough air even in deep water. As it has been serviced just before, Be very caitious about the shop when it really gave not enough air.
No buddy available during the dive?
Be carefull, you will approach the limit sooner than expected. I’n mynopinion its better to carry a bit more redundancy with you. 2 pound of equipment will not destroy your streamline nor your ballance.
The problem is the human body is a CO2-machine and when the gas density in the lungs increases to around 6g/L, it has a much lessened ability to get rid of it by exhalation.
This can very easily result in CO2-buildup and following narcosis.
6g/L density is roughly equatable to around 30m on air/nitrox, so the narrative does make sense.
The big question is how some organizations teach diving well beyond that limit on air/nitrox without informing their divers about the (very well established) risk they’re being exposed to, as relating to hypercapnia.