An age-old question: ways to 60m.

[leadduck]

Pardon, buy would you care to clarify, as in all seriousness, even after reading the rest of your post, I am just not sure what you mean by this statement.

"That's a very plausible observation and not a contradiction."

meant that your observation that you often heard divers complain about overbreathing their regs and not getting enough air at depth, does not contradict the idea that the problem is caused by internal airways resistance in their lungs due to high gas density of air below 35m, because this physiological internal problem feels to the diver as if the reg doesn't work. They think it's the reg and complain about it, but actually it's their own airways that keep them from getting more air. Buying a better reg won't help, only lowering SAC rate and breathing more slowly, or using a gas with lower density will.

 

[Kay Dee]

"That's a very plausible observation and not a contradiction."
meant that your observation that you often heard divers complain about overbreathing their regs and not getting enough air at depth, does not contradict the idea that the problem is caused by internal airways resistance in their lungs due to high gas density of air below 35m, because this physiological internal problem feels to the diver as if the reg doesn't work. They think it's the reg and complain about it, but actually it's their own airways that keep them from getting more air. Buying a better reg won't help, only lowering SAC rate and breathing more slowly, or using a gas with lower density will.

OK, understand what you were getting at now. Thanks. But are you trying to tell me that some regs cannot be overbreathed at almost any depth, shallow or deep, in certain situations?

As for the now bolded above, that should be what everyone strives for, especially the deeper one goes, and to try and maintain the 'hairyer' the situation. But as we know, in some circumstance it takes a lot of mental strength (for want of a better word) / training and experience to do that in all situations that may arise. And even then, both of the bolded above will likely go up to a certain degree, no matter how well 'prepared' you are.

 

[PfcAJ]

OK, understand what you were getting at now. Thanks. But are you trying to tell me that some regs cannot be overbreathed at almost any depth, shallow or deep, in certain situations?

As for the now bolded above, that should be what everyone strives for, especially the deeper one goes, and to try and maintain the 'hairyer' the situation. But as we know, in some circumstance it takes a lot of mental strength (for want of a better word) / training and experience to do that in all situations that may arise. And even then, both of the bolded above will likely go up to a certain degree, no matter how well 'prepared' you are.

I’m sure you can run into issues at some point, but SP had like 130 people breathing off a single mk25 some years ago as a publicity stunt.

 

[CG43]

They think it's the reg and complain about it, but actually it's their own airways that keep them from getting more air. Buying a better reg won't help, only lowering SAC rate and breathing more slowly, or using a gas with lower density will.

Agreed, the regulator is not the problem.
However, the diver at 50 m who thinks he needs more air only needs less CO2 .
The question is how to get rid of the evil CO2 as effectively as possible.

Second stage , mouth , throat , bronchi and alveoli form a dead space which cannot be avoided .
To leave a small amount of CO2 after exhalation, you have to exhale deeply.
When inhaling, the residual amount of CO2 is diluted with the low-CO2 inhaled air, the more you inhale, the lower the CO2 concentration will be . After that, the amount and concentration of CO2 increases due to the supply from the venous blood until the respiratory threshold is reached and exhalation begins.
In order to keep the average CO2 value as low as possible, the starting value must be as low as possible, and that requires a deep exhalation followed by a deep inhalation , followed usualy bei a rest .

When I see videos of divers, some breathe so effectively and others breathe quickly and rather shallowly.
It should not surprise anyone that the latter is not good at a depth of 50 meters.
I myself dived with divers who had the greatest difficulties at depths between 32m to 52m .
But after some "effectively breathe" trainig we could dive much deeper without significant problems.

 

[Kay Dee]

I’m sure you can run into issues at some point, but SP had like 130 people breathing off a single mk25 some years ago as a publicity stunt.

Say no more, of fourse, the venerable mk25 no less.

 

[Blackcrusader]

Buying a better reg won't help, only lowering SAC rate and breathing more slowly, or using a gas with lower density will.

I have a decent SAC rate so maybe that helps me with deep air dives. I;ve never felt being restricted on breathing at depth. Have I had deep dives on air where I needed to work out on a dive, sure. But I still try to maintain my slow deep inhales and exhales.

One thing some people have noticed is that I kit up and "rest" before a dive. I like to be calm and not excited. I've seen divers kit up rush to exit the boat and they are all over the place. Had a group of 14 Spanish divers do that in Maldives. Our group just avoided them lol.

One German couple in our group the wife is a midwife. So she understood about SAC rates and was really surprised at mine. Her husband was a large lad like me but we are not comparable on gas consumption. They were also more than 35 years younger than I am

She asked me why I liked to kit up early 5 mins before others. I told her firstly I am older and slower, I weigh a lot, so I like to take my time and not rush things. I also told her it took time and many dive vacations for me have this low gas consumption. As I was sitting she asked to check my heart beat.
Dang she says 55 bpm when resting. Does that help me also? Can't say. I also don't like to do dives where a lot of exertion is expected and had a few of those in Fuvamulah in May. I love drift dives or slow current dives going with the current. As I am getting older I tend not to be wanting to do dives deeper than 40m - 45m depth. But it there is something really interesting I might do so. Like a hammerhead cleaning station at 50m in South Lombok. Only air dives there.

 

[Kay Dee]

I have a decent SAC rate so maybe that helps me with deep air dives. I;ve never felt being restricted on breathing at depth. Have I had deep dives on air where I needed to work out on a dive, sure. But I still try to maintain my slow deep inhales and exhales.

This.

 

[Blackcrusader]

This.

On my best dives with slow currents my sac rate is like this gragh from a dive this year

Old and slow seems to work for me

 

[Kay Dee]

Old and slow seems to work for me

You betcha! And even before I got old (in years) I always practiced slow u/w, although occasionally excitement got the better of me when chasing a photo, and the SAC rate whent up, say like below*.

*Believed to be the very first sighting of bait ball action at Cocos Island (Costa Rica), according to the liveaboard Undersea Hunter's then owner / skipper Avi Klapfer (who, along with my wife, was next to me making his own photos). And not that the following will mean much to some of the folks here that came down in more recent showers, but one of the worlds very best u/w photographers (still regarded as such to this day), Chris Newbert, was in another panga elsewhere and missed it. To say he wasn't happy, as anyone who knew / knows him well will attest, well..................................Anyway I digress, so beg pardon.

 

[old frogman]

G

Agreed, the regulator is not the problem.
However, the diver at 50 m who thinks he needs more air only needs less CO2 .
The question is how to get rid of the evil CO2 as effectively as possible.

Second stage , mouth , throat , bronchi and alveoli form a dead space which cannot be avoided .
To leave a small amount of CO2 after exhalation, you have to exhale deeply.
When inhaling, the residual amount of CO2 is diluted with the low-CO2 inhaled air, the more you inhale, the lower the CO2 concentration will be . After that, the amount and concentration of CO2 increases due to the supply from the venous blood until the respiratory threshold is reached and exhalation begins.
In order to keep the average CO2 value as low as possible, the starting value must be as low as possible, and that requires a deep exhalation followed by a deep inhalation , followed usualy bei a rest .

When I see videos of divers, some breathe so effectively and others breathe quickly and rather shallowly.
It should not surprise anyone that the latter is not good at a depth of 50 meters.
I myself dived with divers who had the greatest difficulties at depths between 32m to 52m .
But after some "effectively breathe" trainig we could dive much deeper without significant problems.

Good point. Many people are unaware that CO2 is narcotic as well as toxic. Buhlmann believed that CO2 was more responsible for narcosis than nitrogen.

In the 1940s Siebe Gorman (manufacturer) developed a CO2 Scrubber to be used in conjunction with the British Navy hardhat suit and enabled Navy divers to work as deep as 250 ft on air.