DIR and computers

[cornfed]

Stephen Ash once bubbled...
Would someone explain this, please?

SA

Hmmm....

I wonder where I could find out more about this?

 

[MXGratefulDiver]

DSJ once bubbled...


Very good points. Where would I find these BRW papers?
Where can I find a good deco software program to play with? Any suggestions for a program that would work best for this investigation?

David

BRW is Dr. Bruce Weinke. You can order his text here ...

http://www.nauitec.com/manuals.html

Or if you have Adobe Acrobat, you can access some of his work here ...

http://home.earthlink.net/~toddclagett/NovaTech/sdeco.pdf

On another note, I have a request to make of Mr. Kane.

Sir, I'm just a lowly divemaster ... and I work with OW classes on a regular basis. You asked at the beginning of this thread that we focus on topic, and avoid flaming. I respect that, and am happy to see that everyone else has as well. However, having read everything you wrote in this post, I do object to your contextual use of terms like "criminal" and "silly" when referring to how people like myself work to introduce people to scuba diving. I assure you that I take their safety every bit as seriously as you do.

You say that the industry is moving away from teaching tables, in favor of "selling gear". Gee ... don't the DIR folks get upset when someone makes a similar claim about their program? So do I, when you make that claim about mine. Furthermore, if the industry is moving away from teaching tables, what exactly did our most recent OW class spend more than two hours working on the night before last ... and why? The simple answer is that teaching tables is as much about emphasizing the importance of decompression theory as it is teaching the importance of dive planning.

We teach a safe ascent rate of 30 fpm ... and emphasize this to students by going through some examples of how long it should take them to go from one depth to another. We do the practice the same emphasis in both the pool and OW dives. We stress the importance of safety stops ... even though NAUI "officially" says they're not needed for no-deco dives. We introduce them to the "rule of halves" ... the recreational equivalent of your technical "deep stops" ... even though Dr. Weinke's work suggests they're not necessary unless you exceed 80 fsw ... which OW students do not.

I totally agree with what you say about not relying on a dive computer to tell you when you're approaching NDL. We teach that to our students. We teach them that it's important, when using a computer, to understand all the data that's being presented to them. We teach them to not exceed deco limits because, it that computer fails, they would otherwise not have the option to simply ascend and end the dive.

So does every other instructor I know ... and I've sat in on OW classes taught by PADI, NAUI, and YMCA instructors (to date).

I realize that we're coming at this from totally different perspectives ... I work almost exclusively with OW students and new divers wanting to work on basic skills, while you work almost exclusively with more experienced divers wanting to develop technical skills.

While I can, and do, respect your knowledge, I would ask you to please reconsider the words you choose when describing mine. If you want to avoid flames, please choose your words more carefully ... because some of the ones you've so far chosen are inflammatory. I will ask you to show people like me the same respect you expect us to show you.

Thanks ...

... Bob (Grateful Diver)

 

[cornfed]

DA Aquamaster once bubbled...
The 120 rule makes sense as a backup if your computer takes a dump on you but I have to agree it lacks precision and, the way MHK has desribed it, assumes NDL's are linear.

Where does Mike make that assumption?

 

[MHK]

NWGratefulDiver once bubbled...



On another note, I have a request to make of Mr. Kane.

Sir, I'm just a lowly divemaster ... and I work with OW classes on a regular basis. You asked at the beginning of this thread that we focus on topic, and avoid flaming. I respect that, and am happy to see that everyone else has as well. However, having read everything you wrote in this post, I do object to your contextual use of terms like "criminal" and "silly" when referring to how people like myself work to introduce people to scuba diving. I assure you that I take their safety every bit as seriously as you do.

... Bob (Grateful Diver)

Bob,

I apologize if my language wasn't partcularly PC as my intention is not to ignite a flame war. Upon reflection I see where some could read my comments in a context with which they weren't intended and for that please excuse my lapse in language. I was just trying to emphasize the systemic reduction of quality training and the move towards on-line classes, classes taught over the telephone and so forth and in my view these ideas are deluting the academic process, but I should have been more careful in my comments.

BTW, I do acknowledge that there is a wide variety of talented instructors from many different agencies, but some of the ideas that start at corporate HQ have recently leaned towards market share to the detrement of safety..

Regards

 

[MikeFerrara]

DSJ,

there's some stuff here. I have hard copies of some stuff BRW wrote on reverse profiles but I'm trying to remember where I got them from. You'll find it for sure in his book "Technical Diving in Depth"

here

 

[DSJ]

MikeFerrara once bubbled...
DSJ,

there's some stuff here. I have hard copies of some stuff BRW wrote on reverse profiles but I'm trying to remember where I got them from. You'll find it for sure in his book "Technical Diving in Depth"

here

Thanks for the reference Mike. I certified back in 1986 and didn't get much in the way of decompression theory. Probably due to there not being as much work done back then. The GAP website looks like a good place to start a study of the subject.

This board is a great place to learn what it is I don't know enough about. It started with trim, and now I've got a new subject to study.

David

 

[GreenDiverDown]

Pug...

I thought this thread was going just fine. It didn't seem to me that folks were trying to argue with MHK. It seemed to me that folks were just discussing it. As for me, I'm truely trying to understand what he is saying. I thought that I was pretty smart...got lots of degrees and such....I'm definitely open-minded about this subject...but I still don't quite get it. Sorry.



MHK,

We're almost there, man. I understand what you're saying about the 120 rule. . But please continue. I know some of the 'tricks' for figuring repetitive dives but I'd like to know how you do it.

Please go on and tell us the "rest of the story"...for the purpose of discussion only, of course.

SA

 

[Custer]

Uncle Pug once bubbled...
... for some folks.

For others... well... they just need to stick to their computers.

Mike has done an excellent job explaining the concept... but some folks would rather argue than learn. Oh, well.

Some would say arguing is better learning that blind acceptance.

Some of us understand it quite well, have Decoplanner (and many others) and several types of extended range training, and choose to use a computer.

Both of us are blindly guessing at our deco status, it's just that my computer has a much more accurate picture of the actual dive, than the computer at home that you cut tables with yesterday.

Uncle Pug once bubbled...
Personally... I started without a computer... and in the years between then and now I've had a few of them... and they are OK if you like them... and necessary for some of the folks I've read posting here (those who seem to lack comprehension.)

Some might think that the ones that lack comprehention are those that think they can use blind guesses to mentally keep track of their deco status more accurately than a dive computer can (that's pretty cranky, btw, Pug).

Uncle Pug once bubbled...
But for me... I don't like or need them.

So I see. But you can't do the dives I do as a consequence, at least without severe run time penalty. I may go from the screws to the pilot house, and then decide I want a picture of the screws. That's simply not an option for you. I can spear that last fish, go after that last bug, in complete safety. I can ride my no-deco limit, or even decide to incur a stop.

Uncle Pug once bubbled...
I like keeping a mental picture of where I am in my dive profile and adjusting the amount of time I spend shallow and ascending based on that.

Like to compare that to my computer in a 7 dive livaboard day. How do you figure in surface interval, I wonder?

Uncle Pug once bubbled...
In other words I actively control my profile...none of this:
up/down/up/down/gladmycomputeriskeepingtrackofthisup/down/up/down/up....

Like I said, it works fine for the dive profiles you choose to limit yourself to.

" up/down/up/down/gladmycomputeriskeepingtrackofthisup/down/up/down/up" is simply the way I dive, and, no reason why I shouldn't.

 

[cnidae]

DSJ once bubbled...

That would indeed be scary. How many computers would do that?

Um, your Cobra does that. Like I said in my first post to this thread many computers give you ceilings, not stops. Once your Cobra goes into deco it will give you a 10' ceiling not a deep stop.

DSJ once bubbled...
Fortunately the Cobra I use is much better if you mess up and incur deco in that it calculates multiple deco depths and allows for continuing offgassing as you ascend.

I found all Suunto computers to be terible with the deco depths. I've looked at my deco profiles and did'nt see the off gassing I tought I'd see.

 

[Uncle Pug]

Custer once bubbled...
it's just that my computer has a much more accurate picture of the actual dive, than the computer at home that you cut tables with yesterday.


(that's pretty cranky, btw, Pug)


up/down/up/down/gladmycomputeriskeepingtrackofthisup/down/up/down/up" is simply the way I dive, and, no reason why I shouldn't.

1. Folks keep missing this one. They can't conceive that there is something other than computer on your wrist or computer on your desk. I don't *cut tables*.

2. I know

3. I know