computer useage in DIR ? ?

[GreenDiverDown]

Braunbehrens once bubbled...


Please explain this statement. Why am I a poor DIR representative, and how do I do more bad than good. If you are going to accuse me of something, please be specific and give me specific examples.

Thanks.

P.S. It is not my intention to hit anyone over the head with a 2 by 4, like some DIR advocates do. I simply explain the reasons behind the choiced I've made. If I have been rude in any way I'd like to know about it so I can monitor it in the future. One's on-line presence is often a poor reflection of one's personality.

Rather than spend the time to go back and review every post you have made that I feel has put DIR in a bad light, I would rather just try to call you on it when it comes up in the future. I'm sure you mean well but for some reasons that I will not go into here and now you just blow the message over and over one way or another.

Sorry, perhaps I'm being unfair. Perhaps I'm just cranky today. As a matter of fact I am cranky today...I've been shoveling 30 tons of gravel and it's at least 100 degrees outside...and...I'm getting the run-around by my dealer on the new F350 Crew Cab Dually 6.0 Powerstroke diesel that I have been trying to buy.

Gotta run.

SA

 

[jonnythan]

Stephen Ash once bubbled...


Rather than spend the time to go back and review every post you have made that I feel has put DIR in a bad light, I would rather just try to call you on it when it comes up in the future. I'm sure you mean well but for some reasons that I will not go into here and now you just blow the message over and over one way or another.

Sorry, perhaps I'm being unfair. Perhaps I'm just cranky today. As a matter of fact I am cranky today...I've been shoveling 30 tons of gravel and it's at least 100 degrees outside...and...I'm getting the run-around by my dealer on the new F350 Crew Cab Dually 6.0 Powerstroke diesel that I have been trying to buy.

Gotta run.

SA

Personally, I've noticed that lately PB has been quite good and patient answering questions to the best of his ability.

BTW..... nice truck

 

[runvus4]

While his style may not jive with what you may want, Braunbehrens approach is much better than a lot of the vocal DIR proponents on other forums. We seem to have mainly a decent bunch on Scubaboard so far. He is taking the time to explain the reasons behind his personal decision instead of beating us over the head with the book answers and no attempt at explination.

I to would like to find out the method is that the DIR divers use to make computers obsolete for the "blown dive plan/backup plan on the fly calculations" scenario without having to attend DIRF, but I'm realistic in that none of the other agencies that teach deco procedures would be happy with their members to giving "crash courses" in deco procedure on message boards.

 

[Uncle Pug]

... just what is it you want to know?

 

[Braunbehrens]

Charlie99 once bubbled...


1. Does your method keep you within NDL at all times, or does it simply clear your deco obligation by the time you get out of the water?

2. Have you used your method with single gas, multilevel, repetitive NDL diving of 3 or more dives per day?

3. What is your objection to having an independent calculation (by the computer) of NDL and tissue loading, with which you can compare your mental on-th-fly calculations?(this is in the context of single tank, single gas NDL diving)

The above 3 questions should not require you to put info onto the web that might be dangerous.

Charlie

Ow, my ears!

1) I can stay within NDL's if I chose to, but this is really the wrong thing to ask. There is no such thing as a "no decompression limit". Every dive is a deco dive. This is why I'm hesitant to delve to far into this stuff, it DOES require looking at deco in a totally different way.
2) Yes
3) Oh god, you're not going to make me repeat all those reasons why we don't use computers, are you? I'll give you a couple.

I don't do a 3 mn safety stop. I do different stops, and the computer won't like this and will penalize me for it or worse start beeping at me.

I might even bend the computer.

Do you remember when you were a little kid, and didn't know what a word meant? If you had to look it up in a dictionary a couple of times, you'd remember it's meaning. If someone just gave you the answer, you'd have a much harder time remembering it.

Computers will make you lazy, and you will end up depending on them.

Computer algorithms are written for everybody, including people who are not in shape (to be polite). Why should I limit my diving because someone else has a body composition that is harder to offgas?

I think that if you want to use a computer for a while as "training wheels", then that's one way to go. But I think the best way to learn to ride a bike is to never use the training wheels in the first place. It's too easy to do a face plant with them, and you won't learn how to balance on the bike. It will take longer.

So to answer your question, I have no strong objection, I just don't think it's the best way to go. Putting it on your arm however, is IMO a mistake, because you simply will not learn how to do it yourself. Another good analogy is using a calculator insted of learning multiplication tables. If you use the calculator, you won't learn the tables.

 

[MikeFerrara]

Charlie99 once bubbled...
Your statements about this not being taught in DIRF doesn't match statements made on this board by MHK, who is a GUE DIRF instructor. Interesting discrepancy.

No discrepancy really. We have discussed/argued this many times on the board. Some have taken DIRF classes that addressed "ön the fly calculations" and some have stated that they have taken classes where it was not addressed. Ask 0-ring about his class.

Of course there are many types of diving where it is much better to do a multigas plan on a PC or Palm, write down the classic variants (just deeper, just longer, deeper and longer, quick bailout) and go diving.

There are lots of other types of diving (single AL80 repetitive diving, particularly on a liveaboard) where firing up a PC doesn't make a lot of sense. One can fudge and estimate, but IMNSHO, it a lot better to use a computer and use your fudge factors and estimates to do a validity check on the computer.

Again I have pointed this out before also. When I look at the profiles that some are doing on resort boats the first thing I notice is that I wouldn't do it at all. At least not that way. I'd rather not do those 100ish dives without O2. I'd rather not go to 100 ft with a single 80. I have and I might again but for me that's doubles country. I certainly wouldn't stay there til the NDL got looking short and then go to 15 ft for a three minute safety stop. The computer says that's ok. I disagree. So, what has the computer done for me?

It is also clear that one can dive safely dive without a computer since whether or not you stay inside NDL is not important provided you have adequate gas and do appropriate stops. I suspect that this is really the DIR method, but with many of them not realizing that NDLs are being exceeded.

My frustration is that repeatedly DIR or DIR wannabe divers make blanket statements saying the use of computers are bad, and when asked for a description of how they would handle repetitive multilevel dives, they fail to make any reasonable suggestions.

Actually MHK has answered questions about how he recommends doing "table like" multilevel calculations in your head for "no stop dives". UP has given his multi level methode in detail. He even asked every one to check it out with software and see if there was an instance where it wouldn't work.

I've been trading e-mails with a diver who's buddy was bent on a dive they did together. This person is strugling trying to figure why one was bent and not the other. Their computers were plenty happy with what they did. Looking at their profile, I thought it sucked. If you assume the computer was right then it does indeed make it hard to understand why one was hit. OTOH, if you start with the assumption that the computer is full of it then it all makes more sense.

 

[BigJetDriver]

In reading some of the posts on this section of the "Board" I feel as if I have stumbled into a nest of Luddites, or perhaps the "Amish Diving Society"!

Let me see if I can get this straight by analogy.We did manage to put airplanes in the air by doing math on paper with pencils (and a lot of by-guess-and-by-golly). With sliderules we put better ones in the air. With some rather primitive computers, and sliderules, and brainpower we put spaceships on the moon. Now we have computers that are fantastically better, helping us go farther and faster. Despite all of this, some of you are saying that we should turn the computers OFF and we will be able to do things better?

On any normal day, I take an aircraft weighing hundreds of tons, loaded with thousands of pounds of jet fuel, freight, and hundreds of people into the sky. I direct that aircraft through thousands of feet of our atmosphere, and many thousands of miles around our globe to...say...Gatwick Airport, in England. I shoot an approach in the fog, usually, and land on the centerstripe. I taxi in, and the folks wander off on their holidays or business.

Now, can I do that with my trusty E6B aviation slipstick, my pencil, and my paper aviation charts? Of course I can! I have done many, many times in the old days!

Do I do it MORE accurately, and efficiently if I utilize the myriad computers, sensors, GPS units, ring-laser gyro units, and high-speed processors that I have on board my Boeing 777 "space-ship"? Do I even have to ask that question? If they all fail, I will go back to doing it by hand, but who in his right mind wants to?

If I understand what's being said here, however, I should, according to some, turn off my computers and "Hand-Job" it across the pond because "computers rot the brain"? Trust me on this one, guys and gals, you would not like the results. Even though it would be safe, it would be nowhere near as efficient or comfortable.

Now when it comes to diving, I currently utilize a VR3 on a link so I can utilize its capability to track "real-time" PO2 to accurately figure the inert gas fractional loading and thereby more accurately
calculate my decompression requirement. That, combined with the capability of the HammerHead, gives me aviation-style triple-redundancy in both sensors and computing power. Nevertheless, as taught by good practioners of the art, I carry back-up tables in the roll-up vinyl form as provided by IANTD.

You say I should shut off the computers and do it by hand because it is more accurate? When did human beings become capable of taking sensor readings tenths of seconds apart and re-figuring the computations those readings affect on a second by second basis? If you are that capable, more power to you. You must be one of Professor Xavier's team. (I personally will not believe that a human is faster than a microchip until it is verified by someone like Dr. Richard Vann of DAN Research, or Dr. Bruce Wienke of Los Alamos National Laboratories.)

You say I should shut off the computers and do it by hand because you don't like Haldanian models? I hate to tell you, folks, but unless you are using the Bulk Diffusion, or Thermodynamic Models, for instance, it is ALL some variation of the old goat-benders work.

You say I should shut off the computers and do it by hand because otherwise I can't get the best use of my helium without the Reduced Gradient Bubble Model? Well, I do utilize Abyss Commercial Version, which has the RGBM, on my workstation and my laptop. I have to grant you that the VR3 is still staight Buhlmann. I will either have to persuade Kevin Gurr to change his model, or switch to the Explorer.

I do have some bad news for the Haldane-haters, however, and that is the fact that the RGB models in current use in diving constitute one model or algorithm mathematically "wrapped around" a basic Haldane model. These are not my words. These are the words of the man who did the work, Dr. Bruce Wienke. (See Technical Diving in Depth by B. Wienke)

Again, if you say I should shut off the computers and do it by hand because it is more accurate that way, I can only respond with an old Brit saying: "Pull the other one, mate. It's the one with the bells on it!!!!"

 

[MikeFerrara]

Charlie99 once bubbled...


A GUE instructor comes on this board, rails about how bad computers are because they use Haldane models instead of RGBM, but the dive planning program sold by GUE is pure Haldane.

Haldanian in that it is a gas absorbtion model, yes. However, it also uses Bakers gradient factor controlled deep stops.

Many divers don't use these schedules as the software prints them but rather point out that the schedules from this software require less modification to get what they're after than some other programs.

Speaking of gradient factors...

First notice the huge effect that adjusting the upper and lower gradient has on your schedule. Look at what happens to the "NDL" for a given profile. Which "NDL" do you like better? What does your computer or tables say the "NDL" is?

If you make this comparisson the "NDL" will become a very blurry line. So much so as to seem abscure and almost meaningless. However, at the same time the NDL becomes less clear patterns in the ascent schedule will emerge.

In contrast, when you look at the computer or for that matter the tables the emphisis clearly is on the NDL.

 

[MikeFerrara]

BigJetDriver69 once bubbled...



Now when it comes to diving, I currently utilize a VR3 on a link so I can utilize its capability to track "real-time" PO2 to accurately figure the inert gas fractional loading and thereby more accurately
calculate my decompression requirement. That, combined with the capability of the HammerHead, gives me aviation-style triple-redundancy in both sensors and computing power. Nevertheless, as taught by good practioners of the art, I carry back-up tables in the roll-up vinyl form as provided by IANTD.

Could you define accurate in the context of decompression?

As a pilot you use weather reports. They take accurate measurements all over the world and using sophisticated methods generate predictions that are often wrong.

 

[Diver0001]

Uncle Pug once bubbled...
... just what is it you want to know?

Braunbehrens has 2 pages of some kind of tables that he uses to make some kind of "on the fly" calculations of his dives. Multiple gasses, deco, the works. I've seen references to it before but so far I haven't found anyone who cares to explain how it works.

And when I asked him Braunbehrens said some things with the waving hand that I couldn't follow because it wasn't detailed enough and then started talking about walking in the forest and drinking water. He says the knowledge is too dangerous for people like me (ie. strokes) and I haven't been able to get my middle finger back down since. I'm still feeling insulted. :whack:

Can you try explaining it or at least give me some references for further reading? I'm really very curious.

R..