Reconsidering Deep Air?

[Pressurehead]

As most of you know, Helium will help reduce risk but is a long way from eliminating it.

When the discussion started on the use of Helium this was my exact thought, found it on page 3 of this thread.

 

[Celt]

Indeed, sometimes people do really risky stuff, especially in their youth. Base jumping, wingsuit flying, breath hold cave diving, riding motorcycles without helmets at extreme speeds after having a beer, the list goes on and on.

Just because there are riskier things to do in the world does not make 187ft on air "safe" or even minor (compared to what?). You can dramatically cut the risk of your 187ft dive. Minimize being narced plus having a less dense gas to lessen the CO2 threats. Your choice of gas is analogous to choosing to ride a motorcycle without a helmet. There is a generally available, risk reduction tool right there in front of you and you are refusing to use it because you prefer the wind in your hair. Or are too cheap to buy the helmet. Or think that only other people crash.

*shrugs* dive however you like, but your safe enough arguments are weak sauce.

But the problem with that is I don’t have an issue with narcosis or density, for me a 60 metre dive is the same as a 30 metre one so I have no use for helium, I can pump air and be on a wreck in 2 hours from my home for 50 euro including fuel. I’m living beside hundreds of wrecks. Why would I change what works for me.

 

[Wibble]

As most US spearfishing is done in jurisdictions that preclude RBs, there will be a lot of diving done on air for years to come..

Curious as to where and why RBs are "precluded" in some areas?

 

[Wibble]

But the problem with that is I don’t have an issue with narcosis or density, for me a 60 metre dive is the same as a 30 metre one so I have no use for helium, I can pump air and be on a wreck in 2 hours from my home for 50 euro including fuel. I’m living beside hundreds of wrecks. Why would I change what works for me.

To remember the dive?

45 to 50 metres is do-able on air. However, just to reduce the deco time a slightly hyperoxic mix would be better and it's best done at that depth as a gentle bimble around a wreck, not a crawling penetration. For that helium's my friend.

I love my rebreather - praise be ;-)

(Only a week to go before we're allowed outside to go diving - lockdown's such a bore)

Edit - "slightly hypoxic" ==>> "slightly hypERoxic"

 

[100days-a-year]

Curious as to where and why RBs are "precluded" in some areas?

Illegal in the entire US South Atlantic to spearfish on RBs for most species. That's Carolinas, Georgia and Atlantic side of Florida.

 

[Celt]

To remember the dive?

45 to 50 metres is do-able on air. However, just to reduce the deco time a slightly hypoxic mix would be better and it's best done at that depth as a gentle bimble around a wreck, not a crawling penetration. For that helium's my friend.

I love my rebreather - praise be ;-)

(Only a week to go before we're allowed outside to go diving - lockdown's such a bore)

How do people forget dives, I’ve never forgotten one. How would a hypoxic mix reduce deco?

 

[MaxBottomtime]

How do people forget dives, I’ve never forgotten one. How would a hypoxic mix reduce deco?

That's one of the mantras of the anti-deep air crowd. I must be lucky because I've never blacked out underwater, never forgot part of a dive, and never been bent.

 

[jlcnuke]

How do people forget dives, I’ve never forgotten one. How would a hypoxic mix reduce deco?

I've taken someone down to 130' on air at the local quarry who couldn't remember what they were supposed to do, didn't notice a sign with 1' letters on it 5 feet away, and who didn't remember half of the interaction we had at depth when we surfaced. Narcosis can be a hell of a drug for some people, and loss of memory is one possible effect.

Having said that, I'll go against the crowd and say that "in some circumstances" I don't mind diving relatively deep on air (local quarry for instance goes to almost 160' and I dive that on air). I wouldn't consider such a depth on air in a cave, in the ocean with currents, etc., but at the local quarry that I'm very comfortable with and aware of the relatively few hazards at that depth, combined with no reasonably convenient or affordable helium nearby, I don't mind diving it with air.

 

[Celt]

I've taken someone down to 130' on air at the local quarry who couldn't remember what they were supposed to do, didn't notice a sign with 1' letters on it 5 feet away, and who didn't remember half of the interaction we had at depth when we surfaced. Narcosis can be a hell of a drug for some people, and loss of memory is one possible effect.

Having said that, I'll go against the crowd and say that "in some circumstances" I don't mind diving relatively deep on air (local quarry for instance goes to almost 160' and I dive that on air). I wouldn't consider such a depth on air in a cave, in the ocean with currents, etc., but at the local quarry that I'm very comfortable with and aware of the relatively few hazards at that depth, combined with no reasonably convenient or affordable helium nearby, I don't mind diving it with air.

Yeah I could see how a new diver all excited about a deep dive and apprehensive after hearing all the story’s about narcosis might fail to take in certain events or features. But that could be because their preoccupied by their gear and breathing and everything else there told to watch out for.

 

[jlcnuke]

Yeah I could see how a new diver all excited about a deep dive and apprehensive after hearing all the story’s about narcosis might fail to take in certain events or features. But that could be because their preoccupied by their gear and breathing and everything else there told to watch out for.

The diver had quite a lot of dives and had been to 100' on around 20 occasions. They were simply too narc'd to have any clue about anything when we got to depth (literally could look at their eyes and see blank confusion). Memory loss is a documented effect of narcosis that happens to some people.