Agencies and Nitrox

[Rick Murchison]

MikeFerrara once bubbled...
Here is my concern about not being required to do the dives. ... You need the hands on part. ... Taking the theory and applying it in the field along with the judgment and discipline to plan and dive within the plan is ... required to ... apply the theory.

Bingo Mike.
Though the dives are "optional" in the SSI course, they are "mandatory" in my SSI course.
Rick

 

[Rick Murchison]

Walter once bubbled...
Rick,

"It's beyond the course objective of making a safe recreational nitrox diver."

There's another objective in most nitrox classes. Most people take a nitrox course to get the maximum bottom time. You can't accomplish this if you can't calculate your best mix. It is merely another application of the MOD formula, but many people have a math phobia and will never discover this on their own.

Here's what happens in the Gulf. We plan for a dive on Site "A", depth 85' - ok, shop, run a best mix for me of EAN39 so I can get the max bottom time. After leaving the pier, we find that Site "A" is clobbered, but the vis is great over on site "B" - 100'. Everybody else on the boat with their EAN32 says "let's do that one" and I get to sit it out.
Messing with best mix for an introductory nitrox class is just beyond the scale, scope and intent of the class.
Rick

 

[O-ring]

In VA beach the boat I go off of has a compressor on board...problem solved. Calculate your desired mix for the new site, figure out what you need to bleed down to get the right ppo2, bleed the tanks down a bit, retop with air. In NC, they bank EANx30 almost exclusively...that covers their deepest stuff and you just deal with it when you get blown off the offshore stuff and end up on a 70' inshore wreck.

Agreed that air tops and such might be a little much for an introductory nitrox diver...

 

[The Iceni]

bengiddins once bubbled...
"Required" Nitrox dives are a joke - as long as you get to do some hands on analyzing of the oxygen content of a tank during your course, there is no point to doing the dives. There are no skills learnt on the dive specific to Nitrox, except for the pre-dive planning, ie. choosing an appropriate O2 content for that dive, and hands on experience of using the new tables.

Acting as devil's advocate I was expecting to be told, in no uncertain terms, that my ideas were way off and dangerous. The silence is overwhelming!

MikeFerrara once bubbled...
Here is my concern about not being required to do the dives. ... You need the hands on part. ... Taking the theory and applying it in the field along with the judgment and discipline to plan and dive within the plan is ... required to ... apply the theory.

Surely this is just like learning to use tables or a dive computer where the student can learn far, far more from doing numerous examples and testing a number of cylinders in the classroom?

As I see it a basic qualification just to dive with Nitrox as a breathing medium is far, far less than the more stringent requirement when using rich Nitrox mixes for accellerated deco or to be a "Nitrox dive master", marshal or instructor. The former must be able to demonstrate holding a stop and the last must, of course, be a skilled instructor. A novice Nitrox diver is unlikely to have any part planning a group's diving.

I must now ask what practical diving skills does a novic Nitrox diver require over and above that of any other? Recognising and rescuing an unconcious diver is not confined to Nitrox diving.

Rick Murchison once bubbled. . .
Bingo Mike.
Though the dives are "optional" in the SSI course, they are "mandatory" in my SSI course.
Rick

Rick, can you fully justify why you consider this is compulsory by explaining what I am required to demonstrate in the field that I cannot demonstrate in the classroom many, many times and why, as one of your Nitrox students, I would be required to pay extra for your time supervising such a dive?

To my mind this just means your course simply costs much more than any other SSI course and more than it needs to? :tease:

Raviepoo once bubbled. .
I met an instructor once who told me that he has all of his open water students dive nitrox despite the fact that they are not trained for it because it is "safer." That one remark made me decide to steer clear of the guy and the shop he works for.

I fear you may have misjudged him, Raviepoo. His statutory duty is to care for his charges and as the dive leader/master/marshal I have little doubt that he wil ensure that he he gives his students safe mixes for the proposed dive depths and plans the dives safely, no doubt with added conservatism, possibly even diving to air tables.

To my mind he may have just the right attitude as he knows students are not good a buoyancy control and do yo-yo profiles so he is lessening their nitrogen loading and DCI risk. He is also preparing his students to think Nitrox right from the start.

Diving can be dangerous particularly if the "rules" are ignored.

There are additional rules when Nitrox is used.

Thes rules must be taught and a classroom is the place to teach rules.

These rules must be understood and strictly obeyed.

 

[Walter]

Rick,

In the situation you described, where the choice of mixes is EAN 32 or EAN 36 with a planned depth of 85 ft, the obvious choice would be EAN 36, not EAN 32. Everyone with EAN 36 would also be exceeding 1.4 PO2 at 100 ft.

It is also very easy to explain that dive sites may change and a deeper site might be chosen. Divers can ask, what is the planned site? What is the depth? What is the back up site? What is the depth? Then you plan your mix for the deeper of the possible sites. Of course, you could forgo nitrox entirely in those situations where you can't nail down a depth in advance.

There are other destinations where depth is easily planned. All of your students will not be making all of their dives off the northern Gulf. SSI is certainly more widespread. Seems the class is unnecessarily limiting.

 

[The Iceni]

Walter once bubbled...
Divers can ask, what is the planned site? What is the depth? What is the back up site? What is the depth? Then you plan your mix for the deeper of the possible sites.

Hi Walter,

Should this not read "Divers must ask, what is the planned site? What is the depth? What is the back up site? What is the depth? Then they must plan their mix for the deeper of the possible sites?

All of this is applying the rules of proper planning and is something that comes with experience, not from doing a couple of demonstration dives at the end a course.

In my humble opinion of course.

 

[Walter]

Paul,

I agree with your goal, but divers often fail to do things they "must." They will sometimes ignore training and other times they don't receive adequate training, sometimes we all forget.

 

[The Iceni]

Walter once bubbled...
They will sometimes ignore training and other times they don't receive adequate training, sometimes we all forget.

Quite so, Walter,

This is human nature.

Consider an analogy. To pass a driving test the candidate must demonstrate a certain minimal level of knowledge and competence at the time.

This does not guarantee that he will become a good driver once he hits the roads. Most do and learn from experience, some however do not, mix drink and driving etc. etc. . .