Nitrox on boat with air refill

[JohnnyC]

I did it! I did it!!!!

So, using the IANTD air table, a 12m dive has a NDL of 125 minutes. Now, the dive shop has a horrible blender, absolute window licker, and in trying to mix 36%, they actually mixed 69%. Running GF 35/75, EANx69, at 12m, for 125 minutes, I managed to get 100.3% CNS!!!!!!

But wait you say, 69% isn't a recreational mix! (Nor really a mix that anyone uses, but it's fun it worked out that way) But OP didn't have an analyzer, so it could happen!!!!

Bam! I didn't even need two dives to do it!

No bask in my MultiDeco glory as I pull my tongue firmly from my cheek.

 

[IVC]

But OP didn't have an analyzer, so it could happen!!!

Are you saying that people shouldn't care what mix they are breathing? Doesn't sound too technical to me...

 

[KenGordon]

I have been trying very hard to plan two consecutive recreational dives that will exceed 100% CNS but without any luck. Therefore I got nothing to show.
I hope you can enlighten me on this.

Like this:

https://www.padi.com/scuba-diving/p...og/technical-diving-courses/Rebreather-Diver/

Despite the path, this is the PADI type R course.

Then a single three hour dive. Depth doesn't really matter. 10m would be optimal for infinite NDL.

More seriously, to the OP.

The diving 'allowed' by the (US style agencies') 'recreational' courses has been picked to make needing to properly plan and monitor dives less important. If you don't run out of gas you are good.

This is because the courses have to be delivered in a short time to people who are not especially serious and may not dive very often. Extra complication like oxygen exposure is really optional. That is ok as it is not generally the limiting factor of simple dives.

 

[JohnnyC]

Are you saying that people shouldn't care what mix they are breathing? Doesn't sound too technical to me...

It's a joke. There are too many panties being twisted in this thread. Gear down big shifter.

 

[NAM001]

IVC

I don't think anyone is saying that. I believe you are over thinking the problem. First no agency in their right or left mind will teach a recreational course that requires precision to avoid dire consequences. To teach classes you have to be precise to teach the concept with facts and avoid liability. With nitrox IMO it had but a few purposes. 1. Its use to reduce the effects of nitrogen. 2. how the reduced nitrogen can be used as a benifit. 3. To point out the dangerous aspects of nitrox. (1.4 and 1.6 PPO2). 4. What is ead. 5. What is MOD. It is the kind of course that problems occure on one end of the limits spectrum and not the other. like 1.4 and above can get you and nothing for 1.4 and below. Hence Keep it below 1.4 and it is not a problem. Even a blond with fresh done nails has to work to get hurt. Thje technical world is much more critical of both hgh and low ends of the spectrum. Their high end consequences are the same as the rec divers. Their low end consequences are not a physical price sometimes it is financial. Here is an example. why not just use 21% gas with no nirtogen at all. the would be almost a fix all. Who could afford to pay the helium bill for the fill. Techies have rules like EAD o or their version END of max 100 ft. RTec divers dont go past 100 ft so it is not a problem. In short the deeper you go the more one has to be concerned about absolute accuracy. With exception of MOD that accuracy is not necessary for rec divers. Which by the way you notice that basic nitrox is limited to 40% with a mod of 85 or so. ean32 is good to the rec depth limit.

Are you saying that people shouldn't care what mix they are breathing? Doesn't sound too technical to me...

---------- Post added November 11th, 2015 at 04:30 AM ----------

I rather assumed that from the OP he would have known the mix from the shop when he signed for it. And that his problem was he did not have an o2 meter to measure the new mix once diluted with air on the refill. If he did not know for sure what his mix was from the shop then the problem is his not following basic checking proceedures.

I did it! I did it!!!!

So, using the IANTD air table, a 12m dive has a NDL of 125 minutes. Now, the dive shop has a horrible blender, absolute window licker, and in trying to mix 36%, they actually mixed 69%. Running GF 35/75, EANx69, at 12m, for 125 minutes, I managed to get 100.3% CNS!!!!!!

But wait you say, 69% isn't a recreational mix! (Nor really a mix that anyone uses, but it's fun it worked out that way) But OP didn't have an analyzer, so it could happen!!!!

Bam! I didn't even need two dives to do it!

No bask in my MultiDeco glory as I pull my tongue firmly from my cheek.

 

[Freewillow]

I did it! I did it!!!!

So, using the IANTD air table, a 12m dive has a NDL of 125 minutes. Now, the dive shop has a horrible blender, absolute window licker, and in trying to mix 36%, they actually mixed 69%. Running GF 35/75, EANx69, at 12m, for 125 minutes, I managed to get 100.3% CNS!!!!!!

But wait you say, 69% isn't a recreational mix! (Nor really a mix that anyone uses, but it's fun it worked out that way) But OP didn't have an analyzer, so it could happen!!!!

Bam! I didn't even need two dives to do it!

No bask in my MultiDeco glory as I pull my tongue firmly from my cheek.

Well, since people LOVE calculations, let's take that example. Sorry, I am European, so my calculation will be bars and liters.

Like most recreational divers you have a 12L tank with 200 bars and you return to the surface with 50 bars. Your consumption is thus 1800 liters.
You stayed 145 minutes @ 12m , so a pressure of 2,2 bars.
Your consumption per minute @ the surface is thus 1800/2,2/145: 5,6 liters per minute.


The average air consumption for a good diver is 15L/min, 10/12 for the best ones, over 20 for most beginners.

Do you really believe that a diver that does not understand what we are talking about in this post - no names, on request - can dive with such a low air consumption

OK, granted, his brain does not consume oxygen :banana:

 

[Centrals]

Like this:

https://www.padi.com/scuba-diving/p...og/technical-diving-courses/Rebreather-Diver/

Despite the path, this is the PADI type R course.

Then a single three hour dive. Depth doesn't really matter. 10m would be optimal for infinite NDL.

CCR isn't recreational diving, is it?

 

[JohnnyC]

Well, since people LOVE calculations, let's take that example. Sorry, I am European, so my calculation will be bars and liters.

Like most recreational divers you have a 12L tank with 200 bars and you return to the surface with 50 bars. Your consumption is thus 1800 liters.
You stayed 145 minutes @ 12m , so a pressure of 2,2 bars.
Your consumption per minute @ the surface is thus 1800/2,2/145: 5,6 liters per minute.


The average air consumption for a good diver is 15L/min, 10/12 for the best ones, over 20 for most beginners.

Do you really believe that a diver that does not understand what we are talking about in this post - no names, on request - can dive with such a low air consumption

OK, granted, his brain does not consume oxygen :banana:

I don't believe anything except that you are clearly lacking a sense of humor.....

 

[KenGordon]

CCR isn't recreational diving, is it?

Did you not follow the link? 18m limit etc. I'll paste it for you.


"Who should take this course?

Rebreathers used to be only for technical diving, but not any more. New Type R (recreational) rebreathers are lightweight, easy-to-transport and have sophisticated electronics to simplify their use. Why dive a rebreather? You get longer no stop limits, reduced gas consumption because you reuse most of your exhaled gas, and unmatched wildlife encounters because you don’t release annoying bubbles. The PADI Rebreather Diver course introduces you to rebreather diving to a maximum depth of 18 metres/60 feet and lets you experience things you never imagined possible as a scuba diver."

 

[Freewillow]

I don't believe anything except that you are clearly lacking a sense of humor.....

@JohnnyC. Written communication between two people with different cultures and languages is sometimes difficult.

I understood your sense of humour and just wanted to add a drop of fun over it. My remark was not intended at you specifically. It was an additional sarcasm for the so called "scientist" divers. Regards