Lite Nitrox at 145

[Angelo Farina]

@Nick_Radov is being his usual blunt to the point of rudeness self, but he does have a valid point about getting further training.

145' is beyond recreational limits for any US training agency. It's also deep enough that you can't increase the O2 percentage more than a few points without being concerned about the possibility of O2 toxicity. You should really understand Nitrox physiology before diving it. It's actually super simple. If you can think in meters/bar (1 bar is essentially atmospheric pressure at the surface and every 10m/33’ of depth adds another bar), the whole thing is laid out in a few paragraphs here: IFDI - Nitrox Diver e-learning.

But Nitrox is most helpful in the 60'-130' range. If you are regularly going beyond that, you should really be considering a trimix class. If you can afford the helium anyway. If not, then maybe reevaluate your personal max depths.

Or switch to European-style recreational diving, which allows to use air (aka Nitrox-21) down to 50 m and practice some deco stops during ascent.
Any Cmas or Bsac instructor can train and certify you for this kind of recreational dives, no need to switch to technical, expensive and potentially challenging stuff such as trimix or rebreathers.

 

[Nick_Radov]

Or switch to European-style recreational diving, which allows to use air (aka Nitrox-21) down to 50 m and practice some deco stops during ascent.

TIL that air is less narcotic and has lower WOB in Europe.

 

[rjack321]

Or switch to European-style recreational diving, which allows to use air (aka Nitrox-21) down to 50 m and practice some deco stops during ascent.
Any Cmas or Bsac instructor can train and certify you for this kind of recreational dives, no need to switch to technical, expensive and potentially challenging stuff such as trimix or rebreathers.

The 1990s want their divers back!

The Moody is nice, also worth remembering. Finding a willing charter and suitable buddy after flashing your CMAS card to dive her on air is not going to be easy.

 

[ChuckP]

TIL that air is less narcotic and has lower WOB in Europe.

Loads and loads of BSAC and CMAS divers dead......

Plan your dive, dive your plan

 

[DiveLikeAMuppet]

The 1990s want their divers back!

The Moody is nice, also worth remembering. Finding a willing charter and suitable buddy after flashing your CMAS card to dive her on air is not going to be easy.

Who said you need a buddy? What’s wrong with solo diving? Trying to find a buddy on the boat is a lottery anyway.

Honestly, if you get decent visibility (more than 5 meters / 15 feet) and not much current, it’s fine with air as back gas if you can stay around 40-45 meters and if you dive these depths frequently. Bring one deco gas (50% preferred) for < 15 minutes of deco, a second deco gas for 15 - 40 minutes of deco (80 - 100%, if local dive shops can boost oxygen). Also bring a GoPro because you might not remember as much as you think - nitrogen narcosis really impacts your memory.

If the viz is poor (less than 3-4 meters / 10 - 15 feet), if you need to drop deeper or if you expect to encounter some hazards such as many fishing nets or lines, strong current or could swim inside by accident, do yourself a favour and get trimix.

 

[clownfishsydney]

He asked the wrong question. Nitrox is not a smart choice for a 145ft (44m) dive. I'm not going to waste time explaining the basics of gas selection again, this has already been discussed ad nauseum in multiple threads so anyone who cares can just search the archives. Or take an entry-level technical training course from a competent instructor.

I have only done exactly 500 dives over 40 metres, of which probably 350 or so are on a 26% (give or take) Nitrox, so I think I know what I am doing.

 

[Eastwest]

Thanks everybody for chiming in on a lite nitrox at 145 . My main purpose is to stay a little more clear headed like when a three foot ling cod torpedos in your face then nitrogen narcosis comes into effect and the bumped up O2 may help .

 

[johndiver999]

Thanks everybody for chiming in on a lite nitrox at 145 . My main purpose is to stay a little more clear headed like when a three foot ling cod torpedos in your face then nitrogen narcosis comes into effect and the bumped up O2 may help .

Yup, you definitely need polarized sunglasses and leather driving gloves.

 

[sea_ledford]

Thanks everybody for chiming in on a lite nitrox at 145 . My main purpose is to stay a little more clear headed like when a three foot ling cod torpedos in your face then nitrogen narcosis comes into effect and the bumped up O2 may help .

You are confusing oxygen with helium. More O2 will not help with clear headedness. Helium will.

 

[DiveLikeAMuppet]

Thanks everybody for chiming in on a lite nitrox at 145 . My main purpose is to stay a little more clear headed like when a three foot ling cod torpedos in your face then nitrogen narcosis comes into effect and the bumped up O2 may help .

It’s debatable how narcotic O2 might be. Probably not as bad as nitrogen and not as inert as helium.

If you subscribe to the theory that O2 is not narcotic, at 45 meters your END on air is 45m, on 25% nitrox it’s 42m (9 feet difference). That’s a negligible difference. You need to get trimix if you are worried about narcosis.