DIR- Generic Why use GUE nitrox only

[rongoodman]

Which one requires Halcyon equipment? I like Halcyon stuff and some of my first stages are the H-50Ds.

Neither one, as far as I’ve ever heard.

 

[Lorenzoid]

I clicked the link and read through all the standards and don't see anything at all about GUE specifications or standards for configuring where and how to manage and stow your speargun, fish stringer, cocking device and goodie bag when shooting Lingcod and gathering crab and scallops?

Seriously.... I'm curious.... Are carnivore GUE divers allowed to hunt and gather seafood.....or does having all of that additional equipment violate some GUE rule or standard regarding equipment?

I don’t believe there are any relevant standards. I suppose there is no prohibition if you’re doing it within the standards. Nothing in the standards prohibits bringing extra equipment you will need for a specific dive. For example, many bring photography equipment. GUE makes a big deal about conservation, though, so I doubt someone with GUE training is going to be able to organize a group to do a GUE club hunt. That doesn’t mean you couldn’t go with other like-minded divers.

 

[justinthedeeps]

I think anyone going deeper that 100ft. should be using readily available trimix. After all it hardly makes any difference to the cost.

And on a rebreather!

 

[justinthedeeps]

There’s also some institutional learning going on too. On a dive to 180fsw, I was diving 21/35 and felt a little loopy. Other divers noticed it too. Now the recommended gas for 180fsw is 18/45. Not because of the PO2, but because 35% wasn’t enough Helium for 180fsw. There’s more to standardized gas mixes than just PO2.

Speaking of standardization, maybe lets put some proper figures on this.

"I felt loopy so we changed it" sounds exactly like the kind of subjectivity that led to the need for things like GUE/DIR/TDI etc gas standards.

But I know that wasn't your point.

To be more objective, 21/35 @ ppO₂ of 1.4atm is 57 metres (186ft), where its END/EAD happens to be ~27 metres.

We now know that an END of ~20 metres is quite a bit safer from narcosis. So then you get an MOD (because of narcosis) of only about 43 metres for 21/35, and everyone might start freaking out because wow, how could that be?? Well, the idea of a maximum operating depth is not only about ppO₂ (as said by @DeepSeaExplorer above)

Speaking even more about standardization, GUE should really consider ditching the olde 'imperial' system of measurement. It's time!

The metric system (for diving)

Using the metric system for SCUBA diving

justinthedeeps.com

 

[crofrog]

Speaking of standardization, maybe lets put some proper figures on this.

"I felt loopy so we changed it" sounds exactly like the kind of subjectivity that led to the need for things like GUE/DIR/TDI etc gas standards.

But I know that wasn't your point.

To be more objective, 21/35 @ PPO₂ of 1.4atm is 57 metres (186ft), where its END/EAD happens to be ~27 metres.

We now know that an END of ~20 metres is quite a bit safer from narcosis. So then you get an MOD (because of narcosis) of only about 43 metres for 21/35, and everyone might start freaking out because wow, how could that be?? Well, the idea of a maximum operating depth is not only about ppO₂.

Speaking even more about standardization, GUE should really consider ditching the olde 'imperial' system of measurement. It's time, boys and girls!

The metric system (for diving)

Using the metric system for SCUBA diving

justinthedeeps.com

Every thing is available in imperial and metric in the gue materials and many gue divers switch back and forth depending on where in the world you’re diving.

 

[inquis]

To be more objective, 21/35 @ PPO2 of 1.4atm is 57 metres (186ft), where its END/EAD happens to be ~27 metres.
We now know that an END of ~20 metres is quite a bit safer from narcosis. So then you get an MOD (because of narcosis) of only about 43 metres for 21/35,

The END at that depth is actually ~33 msw, and the MOD for a 20 m END is ~36 msw. It's a little ironic that you linked to your blog, which I presume makes the case that metric is easier.

 

[boulderjohn]

I am having trouble understanding recent posts. Is the argument being made that nitrogen is the only part of a breathing gas that is involved with narcosis?

 

[justinthedeeps]

The END at that depth is actually ~33 msw, and the MOD for a 20 m END is ~36 msw. It's a little ironic that you linked to your blog, which I presume makes the case that metric is easier.

Are you considering oxygen to be narcotic?
Subsurface doesn't agree with your numbers either, unless you check the "oxygen is narcotic" box--which I think is a myth, unless your oxygen isn't actually pure oxygen (argon impurities being the biggest culprit)

Would you care to show the math that you are using?

 

[justinthedeeps]

I am having trouble understanding recent posts. Is the argument being made that nitrogen is the only part of a breathing gas that is involved with narcosis?

Yes. I think there is strong evidence to suggest that pure sources of oxygen are not actually narcotic. I have never heard of anyone who spends time on pure oxygen, or a rebreather doing deco at ppO2 of 1.6, or in a chamber, say that they are narced from it. Think about that!

Another explanation in some cases is that impurities like argon end up getting concentrated in systems that simply "enrich air" by filtering out nitrogen (alone). Membranes, pressure swing etc.

 

[justinthedeeps]

The END at that depth is actually ~33 msw, and the MOD for a 20 m END is ~36 msw. It's a little ironic that you linked to your blog, which I presume makes the case that metric is easier.

You can see all of my maths here, speaking of that

DIY Gas Calculator

Out of interest in the properties of mixed gases, I made this homebaked gas calculation tool, written completely in Google Sheets from basic mathematical formulae. This is actually pretty simple maths, like pre-algebra level. I made no consideration of non-ideal gases. [“Embedded” (view only)...

justinthedeeps.com