DIR and computers

[MikeFerrara]

Stephen Ash once bubbled...
I can certainly respect where you're coming from and I look forward to learning these things in class.

Unfortunately, this whole discussion has become pointless. You can say that DIR offers a better approach but we can not talk about it...or we can only talk about parts of it.

One might be convinced that for a single dive there might be a better alternative to using a table or computer. But without the discussion going further we are left with only your word that this method can be applied to repetitive and multi-day diving.

I believe you. You're probably right. But we can't expect anyone else to believe that the DIR approach is better than tables or computers because we can't tell them how it works for everyday dives. Their only choice is to continue to dive as they were taught...or go take a DIRF and hope that the instructor will cover this. And that's a gamble...'cause it ain't in the book.

Until DIR is ready to share these things most folks will have a hard time believin' that they don't need their tables or computers.

SA

What i'm going to say here doesn't have anything to do with DIR or GUE but...

Stephen, run through some dives on your tables. Look at the RNT after a reasonable surface interval like 1 - 2 hours (whatever you like). What is the penalty for different depths? Can you come up with a rule yourself that will fit the vast majority of situations like mabe considering your depth a few feet deeper or your time a few minutes longer on the second dive? Combine that with good profiles and good ascents and do you think you could pull it off without a copy of the tables in your hand?

Besides if you had an average (profile) depth and a time couldn't you calculate a pressure group if you wanted to?

All they did was sit down and really look at the tables realizing that with good habits it didn't have to be calculated to the inch and the second and came up with a simplified procedure.

The answer is is pretty much on the tables. Any one have any experience with algorythm design?

 

[ScottyK]

DSJ once bubbled...


DIR-F is in my personal plans, but what can the great massess of OW divers do to learn more and improve their saftey? What would the other agencies have to do to be able to present your methods? At what level would you suggest they introduce it?

David

DIR is in your plans (and mine too) because you're part of the small percentage of recreational divers that want to take it to the next level (and I'm not saying that DIR is the only way to do that).

I don't think most of the "great masses" of O/W divers would go through the time or expense even if the classes were more readily available.

Scott

 

[Uncle Pug]

MikeFerrara once bubbled...
realizing that with good habits it didn't have to be calculated to the inch and the second

Good habits like checking your depth and SPG in 5 minute intervals.

Good habits like making sure you have enough gas to do the rest of the dive the way it needs to be done.

Good habits like paying active attention to your unfolding dive profile and running the dive so that the profile is what it should be.

Good habits like buoyancy control, slow ascents, stops (at 30,20,10 for example) and a super slow ascent from the last stop to the surface.

Good habits like diving a standard mix that allows you to remember the EAD.

Stuff like that.

 

[Falcon99]

I'm probably not close to you DIR folks, but the ex aviator in me cannot be ignored when I dive...

I like my computer because I can set the alarm to go off when certain personal limits are reached - such as max depth, max time, pressure (Turn pressure, time left), and the like. This adds another supervisory level to my personal SA.

In addition, it logs EXACT times of my dive. I go through the rec tables using this data after every dive and set rec limits for the next.

Yes, the N2 saturation meter is nice, but it's not why I have the computer. The computer gives me quick data and parameters for keeping the dive safe. I ALWAYS follow the tables. If they get busted (Such as the insane "trust me" dives we had in Cozumel) it is a secondary level of computation to help me stay safe.

It's not a substitute for proper planning, but it DOES add some oversight and convenience so I can enjoy a dive more.

Just my $.02...

James

 

[MHK]

Stephen Ash once bubbled...


Until DIR is ready to share these things most folks will have a hard time believin' that they don't need their tables or computers.

SA

Stephen,

I'm somewhat disillusioned by this comment. I suspect strongly that I give away more free information then nearly anyone, or any agency on the internet, and I know that I've privately given away in PM's even more. But to boil it down to, unless we give it all away on the internet for free "people will have a hard time believin it" is disingenuous to the extreme. Nearly every single person that has taken our class has posted a trip report saying how easily we have broken down various complexities. We are ready, willing and able to "share" all of it, and do so on a weekly basis, in fact we were scheduled to "share" it in your local area but for local political reasons the class was canceled. The point being is that I've been very available to discuss the issue, I've spoken candidly about the genesis of the issue, but simply put it is inappropriate, for a wide variety of reasons, to go any further in terms of teaching decompression theory over the internet. As you stated earlier in another post " Take the class".. Without trying to be too begnin, at the end of the day GUE is in fact a training organization designed to teach scuba diving. While it would be great if we were all Bill Gates type wealthy and could give away everything that took us years to develope for free over the internet, at some point pragmatism needs to come into play and business prudence mandates that we simply can't not, from a business standpoint, give it all away for free. But also from a philisophical point of view, it isn't feasible to teach a class over the internet. The concepts aren't that difficult to grasp, but I, as an instructor, who teaches this stuff week in and week out, simply feel uncomfortable going any further into the specificity of the issue.. I dare say that PADI, NAUI, DSAT, IANTD, TDI/SDI et. al do not go anywhere near as far as we do providing groundbreaking infrormation for free, at some point we must say, enough is enough and to the extent divers want to learn more about it, then we do in fact, teach classes every week..

Sorry if that seems dispositive of your concerns, but I just don't feel it's prudent to go any further then I already have..

Regards

 

[Charlie99]

Uncle Pug once bubbled...
A week ago Shane forgot his Stinger at home. We use them for bottom timer/depth gauges.

He had a <brandname> hocky puck dive computer with the stuff that he keeps at my house so he used that instead.

Part way through the dive he was pointing to his hocky puck and indicating that it was not working.

OK... no problem.

We finished our dive as usual and then he told me what had happened. The hocky puck had gone into what it considered deco and decided not to assume any further responsibility for the dive. It decided to do this by not to giving any further information regarding time and would only show depth.

A bottom timer/depth gauge would not have had the liability heebeejeebees. Nor would a *computer* that could be operated in gauge mode.

Moral... carry a second timing device and don't carry a computer designed by coporate lawyers.

Moral ..... don't dive with people that don't understand the operations and limitations of their equipment.

 

[Charlie99]

MHK once bubbled...
That being said, our thinking is that many [not all], but many divers become reliant on a device that could fail.

Secondly, the way we approach a dive is to teach divers to turn their brain on underwater not to turn it off and rely on devices.

Thirdly, many divers are sold on the computer as a way to extend bottom times. ....., but primarily most in-water computers use a Buhlman based algorithm set to 65% - 80% gradient factor. We refer to Buhlman as a "bend and treat" model. What we mean by that is that it tries to get you shallow as quickly as allowable [60' per minute] when a given tissue group reaches it's M-value, and then keeps you shallow to allow for elimination of accumulated nitrogen.. ...... Buhlman will unnecessarily penalize you because you incorporated deep-stops and/or used a 30 fpm ascent rate. This of course will generate longer decompression then actually necessary.

Hopefully that more fully explains our thinking, but I remain available to answer questions consistent with the disclaimer in the opening paragraph..

Much of your comments on computers seem to be based on the false assumption that the choices are:

1. track depth and time in your head, do all computations in your head, dive a safe profile.
or
2. Blindly follow a computer, pay no attention to profile, go directly to whatever ceiling depth is shown.

Anyone who steps back for a moment and thinks can see that these clearly are NOT the only choices.

In particular, use of a computer to track N2 loading of multiple compartments does NOT mean that you cannot choose to execute ascent rates and stops of your choosing. Use of computer to track N2 loading does NOT mean that you have to turn off your brain and not do your own tracking of N2.

I choose not to blindly reject things. I choose not to blindly reject the detailed depth/time tracking capabilities of my computer. I track depth and time. My computer tracks depth and time. I compare the results.

Why throw away the extra data?

I can execute any desire profile. My computer does NOT tell me to ascend to 10' when in deco. It gives a CEILING above which it recommend that I not ascend above. Often deep stops will clear that ceiling. (In spite of your comments about about penalizing for deep stops).

-----------------

For right now, I'll just note that several of your above detailed statements are incorrect, but the primary point of this post is to point out the FALSE CHOICE you propose of either "no computer" or "blind reliance on computer".

Intelligent use of a powerful tool is the option I choose.

Hope this helps.

 

[newdiverAZ]

I dive a computer, but do not follow it blindly at all. From things I've learned here, and trying those ideas I've come up with some things that I like and make me feel better after a dive. Most of the dives I do are shallower, so ndl's aren't really an issue, gas management is more of a factor. From what I've read here I started doing, (actually should say my buddy and I started doing) atleast a minimum of a slow ascent less than 30 fpm to 15', a 5 minute stop at 15', then a 3 min stop at 10', even longer if we have gas, why not use up the gas?, then a very slow ascent of less than 10 fpm to surface. It made a dramatic improvement in the way I feel post dive. Plus using uncle pug's world's largest waterbed never hurts. I did this on a dive yesterday that was only 38' for 40 mins. I don't rely on the computer I'm just a geek who likes computers. But I would never substitute it for using my head. This is not a deco recommendation as I'm a newbie and still trying different things. But is has made a difference for me. I can understand why MHK or anyone else doesn't want to give out any more info, it makes sense. PADI, who I am certified by, offers no information on the net. But thanx to all of you have given out some tidbits so the rest of us can try different things out. I've also tried these different profiles on GAP software and it seems to make alot of difference in the faster compartments, which "theoretically" are the ones we are worried about with bubble formation right?

 

[GreenDiverDown]

Don't you just hate this media.

First...an apology. Please don't be disillusioned by what I said. I sorta assume that we're friends and that you will read what I have to say from that point of view.

I didn't mean for my comments to be taken personally. I appreciate all that you have shared with us very much. I'm surprised that you take as much time as you do answering all of our questions.

I understand that you have reached your comfort level with this topic and I understand and respect your decision not to discuss it further. I said that in an earlier post...and I meant it.

Likewise, I didn't mean to suggest that you should give away your knowledge for free. But, ya know, that's pretty much what we do around here...we share information...and you, especially, seem very willing to do that. (Thanks, BTW.)

Anyway...let me try to clarify what I meant by "Until DIR is ready to share these things most folks will have a hard time believin' that they don't need their tables or computers."

I'm NOT saying that unless you give it away for free on the internet people will have a hard time believing it. What I AM saying is that people can't toss away their tables or computers until they understand the whole deal. I bet you would agree with that. Speaking for myself, I expect that there is a better way. I believe guys like you know the score. But I can't stop doin' what I'm doin' til I figure out that other way.

Let me put it another way...again speaking as a friend...folks won't understand that there is a better alternative to computer diving unless they understand what that alternative is. If they can only get that in a DIRF with a certain instructor then only those folks that take that class will understand that alternative.

Its tough to take the position that there is a better way to dive when you can't discuss just exactly what that better way is. Do you see what I'm saying? It's almost better not to even have the discussion...or to simply say that 'we have a way that we like but it simply is not something that we are able to explain here...take our class and see if you like it. Otherwise, dive as you were trained or as you are comfortable diving.' I know that there are those that would take pot shots at you for saying it that way but I really don't see an alternative other than laying it all on the table.

I see the problem as this...all the stuff that's taught in a basic open water class is pretty much known to all of us here and as such we feel free to discuss all aspects of that 'stuff' in great detail. But some of the DIR knowledge is only known to a relative few and isn't 'common knowledge'. Inherent in this are problems like...'giving it away for free'...or...'it would be irresponsible to discuss this matter in an open forum'. But pretty soon there will be enough folks around that have been exposed to this stuff in class and they will start talking about it and one day it'll become common knowledge.

Ya know...if this stuff was in "the book" it would make talkin' about it much easier.

Mike,

People will pay to take the class because you teach it. They will pay to take the class because they will get quality training. The folks that take your free tid bits and run aren't gonna pay to take the class anyways.

BTW, I hope we're still friends. My door's always open.

Gotta go... gotta work on MikeF's assignment...and my "Oxygen Hacker's Companion" just came in the mail....yippie!

SA

 

[GreenDiverDown]

...we should recognize that instructors from PADI NAUI SSI YMCA give out info all day long 'round here. Maybe none of it is groundbreaking stuff but still...there's a lot of sharin' from all of the agencies.

I only mean to say that we shouldn't fear losing business because of what we discuss around here and we shouldn't fear discussing things that if used wrong might get someone hurt...we do that all day long, too!

One day it will all be common knowledge and we'll look back and see that not discussing certain issues was pointless and only served to create tensions and hostilities.

I don't mean to offend anyone with my remarks...just sorta thinkin' out loud...

SA