Dive safe! A short story from a chamber operator

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Can you clarify the second one ?
Why don’t you have any consequences ?
Because 100% CNS in the NOAA tables doesnt seem to be based on reality. Pulmonary toxicity is a real thing, the CNS clock adding up CNS time at 0.6,0.8, 0.9,1.0, 1.2, etc is basically not correlated with CNS symptoms that are experienced at higher ppO2s.
 
Do you dive 1.2?
Depends on my activity. If it's just a relaxing vacation dive, I'll set 1.4 in the box. If there's a current or I'm expecting to have to work a bit, I'll set 1.2. Good point, tho' perhaps getting beyond Basic Forum Nitrox, lol!
 
Most folks we see are not so technologically advanced. They are simply people who get to go on their holiday and want to make the most out of it. Of course they don’t think they are doing any thing wrong and many times are not. However that doesn’t mean that some don’t push the envelope a little bit. I still think that for most recreational divers who get the chance to jump in for number 5 with someone else for a dive after a few days of several dives can end up in trouble. Some who sit and plan it out may be absolutely fine, but when you see the results of someone who is not planning it all out, it simply is not something I would encourage anyone to do. I have an op, I make money from people coming out diving, but I still could not bring myself to encourage them to do something that might be detrimental. Would rather run a boat with no guests or give the crew the afternoon off.
 
@Divetech Cayman
Thank you for posting
Very interesting hard hitting post
I suspect you can "Knock on any chamber door" and hear a similar story

My son Dr, Sam IV grew up in a pioneer OC dive family and has been diving since he was very young child. He is a NAUI (LIFE) and PADI Instructor, a 1997 SSI Pro 5000 and board certified ER & Scrips trained Hyperbaric doctor.

We have had and I suspect will have many discussions not unlike your case and with the current trend of minimal "dive instruction"

I attempted but was unsuccessful in directing you to a recent NAUI article about me and my son
so I will ad his portion as an attachment so you can read or ignore.

Enjoyed your very informative post, will share with my son -- please post often
But hopefully not of other "chamber adventures"

Dr. Sam Miller, III


Attachment:

Samuel Miller IV, was a diver almost from birth. Having first mastered bathtub diving as a toddler-the regulator had a long hose and the cylinder was on the bathroom floor-he graduated to the family pool at age 4 using a MSA cylinder with homemade backpack. At 5 years old, he was in the Pacific Ocean. "Not too deep and not far from shore, but he was underwater, and in his own mind, he was a diver," said his father. Miller IV had a lot of encouragement from his family and also from family friends who were diving luminaries themselves.

The photo shows "Sammy Miller" on his sixth birthday getting ready for a dive with Dr. Charlie Brown, NAUI's medical adviser, with whom Miller IV dived many times. Brown was interested in learning how a young child adapted to diving.


By the time he reached his l0th birthday, Miller IV had logged more than 100 open-water dives, and that year, he completed the Los Angeles County and NAUI Scuba Diver courses, although he was too young to be certified. During the summer of his 12th birthday, he was accepted and successfully completed a 40-hour US Divers equipment repair course. At age 18, he became the youngest person listed in Who's Who of Scuba Diving.

In SoCal diving circles, Miller IV was considered a top hunter and freediving spearfisher. When he turned 18, he was accepted for provisional membership in the Long Beach Neptunes Spearfishing Club, and then into full membership.

In his spare time, Miller IV designed, fabricated and sold custom-built teakwood spearguns. His guns had a custom-length balance bar measured to the user's arm length and a handle that was shaped from a mold of the owner's gloved hand in the shooting position. During college, he served on weekends as a deckhand on the dive charter boat Golden Doubloon.


In 1991, Miller IV became a NAUI Instructor (NAUI 13227) and taught scuba at one of the Southern California dive shops. He won a scholarship to the Catalina Chamber course, completed their internship and became a qualified chamber technician. While waiting to enter medical school, he began technical mixed gas diving with his friend Jeff Bozanic, making deep technical dives on a regular basis off the California coast.

After completing medical school in Pomona, California, and an emergency room residency in Kingman, Arizona, he won a fellowship in hyperbaric diving medicine at University of San Diego Medical Center. At the end of the fellowship in 2008, he accepted a position at Marion Regional Medical Center in Santa Maria, California, where he is currently their director of ER/Hyperbaric Medicine.

Miller III summed up much of the feelings of him and his family: "The ocean provides bountiful gifts. It's a recreational area to protect for all present and future generations. Everybody should be able to enjoy it.


SDMIII

@Marie13 CE typical SoCal diver
 
So I'm confused, do you dive with your computer in Air or Nitrox mode? If Nitrox mode, do you calculate NDL using Air tables? Thanks.

It was suggested on this board that I set it for Nitrox with a 21% mix. It didn't work. The computer just assumed I was breathing air. I used the computer NDL, which I understand is less than what it would be if I selected the actual Nitrox mix on my computer. Therefor, more conservative.

However, after reading the posts on this thread I am reconsidering that approach. I always check the depth limit of a particular mix and keep that in mind. However, next time I might just use the correct mix and use NDL - x.

I'm still new to Nitrox and this has been a very informative thread.
 
I'm confused; what didn't work?
 
I'm confused; what didn't work?

I think you were responding to my post. If not, sorry! Just ignore.

My computer did not track O2 even though I had selected nitrox and a mix of 21%. It tracked tissue loading for nitrogen, as if I was on air. I dive with a ProPlus 2. Other computers may work differently.
 
It was suggested on this board that I set it for Nitrox with a 21% mix. It didn't work. The computer just assumed I was breathing air. I used the computer NDL, which I understand is less than what it would be if I selected the actual Nitrox mix on my computer. Therefor, more conservative.

However, after reading the posts on this thread I am reconsidering that approach. I always check the depth limit of a particular mix and keep that in mind. However, next time I might just use the correct mix and use NDL - x.

I'm still new to Nitrox and this has been a very informative thread.
Air is just Nitrox 21.
 
The computer should always be set the the actual mix you’re diving so it accurately tracks the gases. You can then add conservatism by simply not diving to the limits. Then if you have to change your plan, the computer is still accurately tracking the dives. I would not dive Nitrox with a computer set to air, or intentionally to the wrong mix.
 
I think you were responding to my post. If not, sorry! Just ignore.

My computer did not track O2 even though I had selected nitrox and a mix of 21%. It tracked tissue loading for nitrogen, as if I was on air. I dive with a ProPlus 2. Other computers may work differently.
People do this to have a more conservative profile: if you set your computer on air but dive Nitrox, your NDL will be shorter, so you will dive more conservatively.

However, you should be careful about the MOD as other people said as it will indicate 1.4 (or whatever is the multiplier in your settings) for 21% which is deeper.

Personally I think I prefer my computer to show me my real NDL, and if I want to dive conservatively I will just not get close to my NDL and make a longer stop with a slower ascent ...
 
https://www.shearwater.com/products/peregrine/

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