computer useage in DIR ? ?

[jeffyjak]

Hi all:
I'm a new diver, & someday want to learn DIR, so, before I start spending any money on stuff I don't want, . . . . . .
I like the idea of a computer, but . . . . .
I've searched & can't seem to find any statements re: use, or non-use of computers; seems like I've seen comments "depth gauge & timers only....
any advice, suggestions, etc will be appreciated!
jeff

[Cave Diver]

jeffyjak once bubbled...
Hi all:
I'm a new diver, & someday want to learn DIR, so, before I start spending any money on stuff I don't want, . . . . . .
I like the idea of a computer, but . . . . .
I've searched & can't seem to find any statements re: use, or non-use of computers; seems like I've seen comments "depth gauge & timers only....
any advice, suggestions, etc will be appreciated!
jeff

As Pug would say... CRYB!

(computers rot your brain)

The reason you don't find anything regarding the use of computers is simply because they don't use them.

Dives are planned and dove according to that plan, with contingencies built in.

[astrofunk]

Hey Jeffy -

You're probably aware of this, but if not, you should know that computers and bottom timers are not mutually exclusive. That is, most computers can be set to gauge mode, in which case they function simply as a bottom timers.

So if you want a computer for now, go for it. If you later go DIR, set it to gauge mode and leave it.

Two bits of advice: If you do get a computer, don't let it become a substitute for understanding the tables and planning your dives with conscientious gas management in mind. Also, I would recommend going with a wrist mount, no matter what kind of instrument you end up with.

best,
steve

[roturner]

astrofunk once bubbled...
Hey Jeffy -

You're probably aware of this, but if not, you should know that computers and bottom timers are not mutually exclusive. That is, most computers can be set to gauge mode, in which case they function simply as a bottom timers.

So if you want a computer for now, go for it. If you later go DIR, set it to gauge mode and leave it.

Two bits of advice: If you do get a computer, don't let it become a substitute for understanding the tables and planning your dives with conscientious gas management in mind. Also, I would recommend going with a wrist mount, no matter what kind of instrument you end up with.

best,
steve

I agree completely with Jeffy. I think this is a fine piece of advice. <applause for Jeffy> :bravo:

The DIR hardcore would probably scold me for saying that and they'd tell you that buying a computer to put in guage mode is a waste of money but I would do it anyway. You'll probably find that having a computer is practical some of the time and (to be controversial) you'll end up wasting much more money on other things if you go DIR anyway.

R..

[Braunbehrens]

roturner once bubbled...


I agree completely with Jeffy. I think this is a fine piece of advice.
The DIR hardcore would probably scold me for saying that and they'd tell you that buying a computer to put in guage mode is a waste of money

Actually, a lot of the hardcore DIR divers do exactly that, and the reason is that it allows you to download your profiles to the computer.

Also, we do not rely on plans and contingencies. After a while of diving a bottom timer (or computer in gauge mode) you will know what you need to for a given depth and a given gas.

This will allow you to simply dive and know where you're at, and how much deco you need to do.

The biggest problem with computers is what they tell you:

Time's up, better head for the surface.

Every dive is a deco dive, so on every dive I stop at least at 40 ft, 30 ft, and 20 ft for 1 minute. If I have gas and time I'll do a 2 ft per minute ascent from 10 ft, it's excellent practice.

If you do this, most computers will yell at you for violating a "safety stop".

[Charlie99]

Braunbehrens once bubbled...
Every dive is a deco dive, so on every dive I stop at least at 40 ft, 30 ft, and 20 ft for 1 minute. If I have gas and time I'll do a 2 ft per minute ascent from 10 ft, it's excellent practice.

If you do this, most computers will yell at you for violating a "safety stop".

Thanks for the DIR perspective.

What computers have you seen that "yell at you for violating a safety stop" as you describe above? Oceanic, Aeris, etc. will not, nor do I believe will the Cochrans.

[Doc Intrepid]

jeff,

Steve and Braunbehrens offer sound comments.

Computers are tools. Like any tools, they can be used or abused.

In the 'DIR:Fundamentals of Better Diving' text by Jablonski there are numerous photographs in which the diver in the photo is wearing a Sunnto computer. It is to be presumed that the computer is set to gauge mode.

For divers learning about decompression diving, it can be informative to study dive profiles.

If you are indeed a "new diver", there may be other items of equipment that you might want to purchase before you acquire a new computer.

Listen to the comments you will no doubt receive, and make up your own mind.

Doc

[jeffyjak]

Thanks, Doc, et al, for the replies, & advice....

I have a total of 44 dives, of which 5 were my aow class at lake powell, & approx. 24 dives were at no. channel islands, calif....
I consider myself to be a "new" diver.....

What might you recommend as to gear purchases.....

I haven't yet ordered, but will be soon getting the Apex TX-50 second stage, I want to have my own, & that is one that is has been recommended for tech diving.... otherwise, I only own mask fins booties! ! !

I will have to certainly buy things one at a time, budgetary restrictions i.e., first child off to college this fall, etc, etc....

[Braunbehrens]

jeffyjak once bubbled...
What might you recommend as to gear purchases.....


Regulator is definitely the first thing. After that I'd get a suit, because an ill-fitting suit is the pits, and then a BC. Of course I would recommend a backplate and wings.

If you are serious about diving, don't buy a wet suit. You'll want a drysuit soon enough, so hold off until you have money for a drysuit.

It's very difficult to get your weighting right when you don't have your own suit.

In the immediate, you need a timing device, be it a computer, a depth gauge, or whatever. The most importan advice is to stay the heck away from the small SUUNTO devices. I have personal knowledge of half a dozen or so that have failed, including my own. The large SUUNTO devices seem to be fine. I wouldn't bother with anything fancy, just get a Vyper, which can be used in gauge mode, or a similar computer. Don't get anything air integrated blah blah blah.

When chosing a computer, here is my list of must haves:

1) activates automatically when you enter the water.
2) User replaceable battery
3) Gauge mode
4) Downloadable

The vyper fullfills all three of these nicely, but there are probably others.

Good luck, and have fun!

[jeffyjak]

thank you, I feel you've given good advice ;)
I am looking at the aeris atmos 2, it has all of the requirements you suggested..... & the price is right for me....
thanks again!
jeff

[Braunbehrens]

jeffyjak once bubbled...
thank you, I feel you've given good advice ;)
I am looking at the aeris atmos 2, it has all of the requirements you suggested..... & the price is right for me....
thanks again!
jeff

Make sure you look at the warranty. I bought a suunto Stinger, and it malfunctioned several times. Now I don't feel comfortable using it, or selling it. Basically I'm out 600 bucks and I have a very heavy watch.

Come to think of it, it's time to contact SUUNTO about this and see what they have to say.

[GreenDiverDown]

Braunbehrens once bubbled...


Regulator is definitely the first thing. After that I'd get a suit, because an ill-fitting suit is the pits, and then a BC. Of course I would recommend a backplate and wings.

If you are serious about diving, don't buy a wet suit. You'll want a drysuit soon enough, so hold off until you have money for a drysuit.
...




That's the wierdest advice that I've seen in awhile. hmm...I guess you can dive in your underwear while you're saving up for that drysuit.

Decide where you are going to be diving most and then get the appropriate exposure protection. Here in AZ a shorty and a 6mil will let you dive year round and will take you places from the Channel islands to Coz. You can get a lot of "serious" diving in before you go dry.

You should come down to Phoenix, Jeff. We can go to Lake Pleasant and get some dives in. (You can watch me sweat like a pig, as I try to get in the water before my drysuit sucks the life out of me.) We can talk gear and/or DIR.


SA

[jeffyjak]

I'd love to come down & dive pleasant! or, you can come up & we'll go dive in willow spgs! it's above payson, definitely cold there! not a lot to see, but it is blowing bubbles...

actually, I have had no problem at all so far w/ renting my wetsuit.... maybe I've just been lucky... but figured I'd keep renting, & in meantime save up for a dry suit... we had an instructor in flagstaff who used & owned nothing but a drysuit....
even for rocky point mexico!

[Braunbehrens]

jeffyjak once bubbled...
actually, I have had no problem at all so far w/ renting my wetsuit.... maybe I've just been lucky... but figured I'd keep renting, & in meantime save up for a dry suit... we had an instructor in flagstaff who used & owned nothing but a drysuit....
even for rocky point mexico!

That was exactly what I was suggesting! Diving CA you'll want a drysuit eventually anyway, so why blow your wad on a wetsuit. A wetsuit is a nice thing to have, but I have two haning in the basement that I haven't worn for years. Why be cold if you don't have to?

Looks like you're definitely going in the right direction. More fun ahead!

[DIR Tec Diver]

All my personal diving is DIR, and I also am an instructor, so having a computer is important, and poses no violation to DIR as long as it is in Gauge mode when used for that specific type of diving. SUUNTO is by far the best computer to get, but I agree with sticking with the Vyper or Vytec. The Vytec allows you to use multiple EANx mixtures, but if you are doing that sort of diving, you should be using gauge mode anyway, so the Vyper is the best buy. The ability to download your profiles is very important. This is how we analyze our profiles, decompression and understand what is happening on every step of the dive. As you become fully aware of this, the need for the profile deminishes and then you can go with the bottom timer such as the UWATEC.

For the Regs, Apeks are definitely the best choice, but be aware of the ATX50 with the swivel. That will wear in time, and then you will have an issue with the O-Ring. I know from experience because before I became a competent tech diver, I purchased those, and I learned the hard way. You don't want any potential failure points in your equipment, so go with the ATX 100 or ATX 200.

Now for exposure protection. If you do any type of technical diving a 6mm wetsuit is unforgivable. Get a drysuit as was already mentioned previously. There is a big misconception that a drysuit if only for cold waters. Very wrong. The drysuit is the suit of choice not only for exposure protection, but for proper buoyancy, trim, balance, safety and comfort. Even when I have surface temperatures of 40c I use my TLS350 and 200g Thinsulate, and I am not overheated in any way during the dive, and staying warm and comfortable is the key to effective decompression. Using a wetsuit only leads to problems not solutions.

[Epinephelus]

DIR Tec Diver once bubbled...
All my personal diving is DIR, and I also am an instructor, so having a computer is important, and poses no violation to DIR as long as it is in Gauge mode when used for that specific type of diving. SUUNTO is by far the best computer to get, but I agree with sticking with the Vyper or Vytec. The Vytec allows you to use multiple EANx mixtures, but if you are doing that sort of diving, you should be using gauge mode anyway, so the Vyper is the best buy. The ability to download your profiles is very important. This is how we analyze our profiles, decompression and understand what is happening on every step of the dive. As you become fully aware of this, the need for the profile deminishes and then you can go with the bottom timer such as the UWATEC.

For the Regs, Apeks are definitely the best choice, but be aware of the ATX50 with the swivel. That will wear in time, and then you will have an issue with the O-Ring. I know from experience because before I became a competent tech diver, I purchased those, and I learned the hard way. You don't want any potential failure points in your equipment, so go with the ATX 100 or ATX 200.

Now for exposure protection. If you do any type of technical diving a 6mm wetsuit is unforgivable. Get a drysuit as was already mentioned previously. There is a big misconception that a drysuit if only for cold waters. Very wrong. The drysuit is the suit of choice not only for exposure protection, but for proper buoyancy, trim, balance, safety and comfort. Even when I have surface temperatures of 40c I use my TLS350 and 200g Thinsulate, and I am not overheated in any way during the dive, and staying warm and comfortable is the key to effective decompression. Using a wetsuit only leads to problems not solutions.
My BS meter is pegged!
E. itajara

[Braunbehrens]

Were you planning on debating any of this, or did you just feel like venting?

[FLL Diver]

DIR Tec Diver once bubbled...
Now for exposure protection. If you do any type of technical diving a 6mm wetsuit is unforgivable... The drysuit is the suit of choice not only for exposure protection, but for proper buoyancy, trim, balance, safety and comfort. Even when I have surface temperatures of 40c ... Using a wetsuit only leads to problems not solutions.

Interesting take. Could you explain how "a wetsuit only leads to problems"?

Also where are you diving with surface temps of 104°F that you still wear a drysuit?

Marc

[boomx5]

He's right, only strokes wear wetsuits in warm water; kind of like the guy in these videos.

Wetsuit Diving Stroke (http://www.gue.com/classroom/propulsion/index.shtml)

Someone better tell this guy before GUE finds out.

[Uncle Pug]

Somebody needs to set their drag a little tighter... the way these guys hit the bait and then run with it can strip a reel in no time at all.:D

[GreenDiverDown]

Jeff,

You are seeing one of the best things about ScubaBoard. When bad advice is given, it usually doesn't slide by without being noticed.

Think about where you will be diving and get the appropriate suit.
Also, consider that you are a new diver and that tech diving is for later on.

If you are going to be diving exclusively in our mountain lakes and over in Cal you might want to get a drysuit as soon as possible. But if you are going to be diving our desert or going to Rocky Point, San Carlos or Coz, you're going to want the right tool for the job.

And... I don't see how renting a wetsuit until you can afford to go dry will save you any money. They just aren't that expensive. You certainly don't have to "shoot your wad" to get one. How many days can you rent a suit before you have bought it?



SA

[Charlie99]

Braunbehrens once long ago (the 5th post in this thread) bubbled...
Every dive is a deco dive, so on every dive I stop at least at 40 ft, 30 ft, and 20 ft for 1 minute. If I have gas and time I'll do a 2 ft per minute ascent from 10 ft, it's excellent practice.

If you do this, most computers will yell at you for violating a "safety stop".

What computers have you seen that "yell at you for violating a safety stop" as you describe above? Oceanic, Genesis, Aeris, etc. will not, nor do I believe will the Cochrans.

Charlie

[O-ring]

Ditching gas via the purge method would be risky in cold water. Something about willingly dumping gas when in trouble also seems to scare me for some reason too... :D

[Rick Murchison]

The dry suit discussion has been moved here. (http://www.scubaboard.com/showthread.php?s=&threadid=27964)
Rick

[BigJetDriver]

[SIZE=3][FONT=times new roman][COLOR=darkblue]

:confused:

I cannot for the life of me understand why anyone would want to take a good computer and cripple its capability by setting it to run only in gauge mode.

It is, of course, extremely important for divers to have a good understanding of the basis of, function of, and usage of dive tables. It is also important to carry back-up tables for redundancy purposes.

No one, however, can sample all of the variables sampled by the modern computer and calculate their changing effect on a diver's decompression requirements as rapidly as a computer can! (Well perhaps the "Rain Man" could, but...)

The net effect of using a computer in the suggested manner would be akin to putting a blade with no teeth in a power saw. I suppose one could, but why in the heck would you want to? :confused:

[Braunbehrens]

BigJetDriver69 once bubbled...
[SIZE=3][FONT=times new roman][COLOR=darkblue]

:confused:

I cannot for the life of me understand why anyone would want to take a good computer and cripple its capability by setting it to run only in gauge mode.

It is, of course, extremely important for divers to have a good understanding of the basis of, function of, and usage of dive tables. It is also important to carry back-up tables for redundancy purposes.

No one, however, can sample all of the variables sampled by the modern computer and calculate their changing effect on a diver's decompression requirements as rapidly as a computer can! (Well perhaps the "Rain Man" could, but...)

The net effect of using a computer in the suggested manner would be akin to putting a blade with no teeth in a power saw. I suppose one could, but why in the heck would you want to? :confused:

Excellent question, BigJet, which I am happy to answer.

1) Decompression is a much less exact science than we are led to believe.

2) Your brain is a much more powerful computer than the one on your wrist.

3) If someone keeps giving you the answer you'll never learn for yourself.

4) The computer bases it's decisions on algorithms that are antiquated and less accurate then more current theories

5) You are smarter than your computer (again).

6) If your computer craps out it doesn't matter, because you know what you did, why you did it, and how to proceed.

7) We should not let machines run our lives and ...

Hey, wait a sec., look at the time, my tv show is on...gotta run.

With apologies to Bill Watterson

[awarner]

I thought I'd throw this in as well, although most of you have probably read these reasons before. (whether you agree with them or not)

-ARW

Baker's Dozen for not using a Dive Computer By Jarrod Jablonski


1) Dive computers tend to induce significant levels of diver dependance,
eliminating the awareness so common and essential to all diving but
particularly obvious when diving tables

2) Dive computers do not allow proper planning as divers can't properly
"study" the impact of various mixture and decompression choices.

3) Dive computers are of very limited educational benefit as they do not
induce questioning, or proper planning discussions as can be found with
tables and most particularly with deco programs

4) Dive computer programmers often play games with computational process
so that they can take insulate themselves from the risk of taking
largely square profile data and utilizing it on a multilevel dive. These
games tend to result in odd and often ridiculous levels of conservation.

5) Dive computers are expensive and in some cases leave divers with
limited resources carrying equipment that is of far less benefit than
other equipment that may have been purchased.

6) Dive computers significantly limit the likelihood that divers will
track their residual nitrogen groups.

7) Dive computers do not allow for Helium diving in any formats but the
bulkiest and most questionable format.

8) Dive computers will often generate longer decompressions than could
be figured by an astute, well educated diver with experience.

9) Dive computers often create confusion by giving the user to much
useless information, sometimes even obscuring depth and time in favor of
blinking CNS and/or deco limitations.

10) Dive computers can become very difficult to properly if a deco stop
has been violated. Some computers lock up completely while others just
beep or generate erroneous and distracting information. Divers using
mixed gasses are likely to often violate computer profiles.

11) Dive computers do not allow for the educated diver to properly
modify their decompression to account for advancing knowledge such as
the use of deeper stops in a decompression profile.

12) Dive computers do not offer divers as much flexibility in the
generation of profiles with varying conservation. For example the right
mix would allow 100 min at 60 vs 60 at 60 but I might prefer to do one
or the other and indeed might like a compromise. Computers confuse this
issue by not providing divers with the proper information.

13) Dive computers users often ignore table proficiency and therefore do
not learn tables properly. When confronted with a situation where they
can't dive the computer (failure, loss, travel etc) these divers are at
a serious handicap.

[detroit diver]

BigJetDriver69 once bubbled...
[SIZE=3][FONT=times new roman][COLOR=darkblue]

:confused:

I cannot for the life of me understand why anyone would want to take a good computer and cripple its capability by setting it to run only in gauge mode.
......

As mentioned previously, I use mine for the ability to download the profiles onto my home computer afterwards. You can't do that with any bottom timer (that I know of).

I originally used it before I knew any better, but I'm glad I bought it for the above reason.

[roturner]

awarner once bubbled...
I thought I'd throw this in as well, although most of you have probably read these reasons before. (whether you agree with them or not)

Thought I'd throw in a rebuttle from the puddlestompers perspective.


1) Dive computers tend to induce significant levels of diver dependance, eliminating the awareness so common and essential to all diving but particularly obvious when diving tables


nothing to disagree with there. (sorry, must be my first rebuttle :) )


2) Dive computers do not allow proper planning as divers can't properly "study" the impact of various mixture and decompression choices.


Doesn't apply. Puddlestompers don't do mix and they don't do deco.


3) Dive computers are of very limited educational benefit as they do not induce questioning, or proper planning discussions as can be found with tables and most particularly with deco programs


Who cares? Puddlestompers want to have fun. And what's all this about "proper planning"..... you get in the water, you swim around and you come out at 50bar. That sounds like a plan to me. It might not work for JJ but it works for millions of other divers.


4) Dive computer programmers often play games with computational process so that they can take insulate themselves from the risk of taking largely square profile data and utilizing it on a multilevel dive. These games tend to result in odd and often ridiculous levels of conservation.


Better safe than sorry. I don't see the problem here.


5) Dive computers are expensive and in some cases leave divers with limited resources carrying equipment that is of far less benefit than other equipment that may have been purchased.


How much does that fancy Halcyon rebreather cost that JJ rides? And all those scooters? Jeeez. For the money he spends on *fills* a typical diver could buy a new set of gear every year. A computer is a drop in the bucket. And frankly if someone want to spend money on a computer instead of fancy tekky-toys, who is JJ to judge?


6) Dive computers significantly limit the likelihood that divers will
track their residual nitrogen groups.


So what? The computer tracks them. That's what a computer is *for*. To take your mind off of these details.


7) Dive computers do not allow for Helium diving in any formats but the bulkiest and most questionable format.


And that's a damned good thing too because if it accounted for helium most divers would be paying functionality they *really* don't need.


8) Dive computers will often generate longer decompressions than could be figured by an astute, well educated diver with experience.


Who cares. PUddlestompers don't do deco.


9) Dive computers often create confusion by giving the user to much useless information, sometimes even obscuring depth and time in favor of blinking CNS and/or deco limitations.


No they don't. Maybe some of them do but not the good ones. This is simply untrue. Maybe JJ has trouble with them because in terms of computers he's a newbie.


10) Dive computers can become very difficult to properly if a deco stop has been violated. Some computers lock up completely while others just beep or generate erroneous and distracting information. Divers using mixed gasses are likely to often violate computer profiles.


Refer to question 8


11) Dive computers do not allow for the educated diver to properly modify their decompression to account for advancing knowledge such as the use of deeper stops in a decompression profile.


Refer to question 8


12) Dive computers do not offer divers as much flexibility in the
generation of profiles with varying conservation. For example the right mix would allow 100 min at 60 vs 60 at 60 but I might prefer to do one or the other and indeed might like a compromise. Computers confuse this issue by not providing divers with the proper information.


Mix? What's that? is like Air because that's what puddlestopmers dive with. Who cares about all these bells and whistles. Most divers don't need or want them.


13) Dive computers users often ignore table proficiency and therefore do not learn tables properly. When confronted with a situation where they can't dive the computer (failure, loss, travel etc) these divers are at a serious handicap.

Table proficiency? Many puddlestompers don't learn the tables well enough to use them a month after they're certified. For better or for worse the computer has become and will remain an essential piece of dive gear. It's like a buoyancy controller. BCD's never used to be standard gear either but people adopted them because they work and it makes diving easier and more fun. Anyone out there still dive without one? I see JJ has one.

The point is (yes, I am going to spell it out) is that JJ (et al) take their paradigm and project it onto everything and everybody but their paradigm doesn't fit everything and everybody. Doing so sounds as rediculous to me as saying "oh. just take your al80 and swim 5km into a cave with it. You should be ok as long as you're out with 50 bar". The puddlestomper paradigm doesn't fit JJ either. These are two different worlds with two very different sets of rules.

R..

[Braunbehrens]

I'll add a rebuttal to your rebuttal. Soon we'll be swimming in butts.

Just kidding, thought I'd elaborate on a few points:


roturner once bubbled...


Thought I'd throw in a rebuttle from the puddlestompers perspective.


2) Dive computers do not allow proper planning as divers can't properly "study" the impact of various mixture and decompression choices.


Doesn't apply. Puddlestompers don't do mix and they don't do deco.



Every single dive you do is a deco dive. If you are not stopping at all, then you are decompressing on ascent. If you do a safety stop...you are doing a DECO stop. Even rec divers can benefit from understanding how deco works, and how to properly ascend from any dive. As for mix, plently of recreational divers use nitrox. Some even use trimix.





3) Dive computers are of very limited educational benefit as they do not induce questioning, or proper planning discussions as can be found with tables and most particularly with deco programs


Who cares? Puddlestompers want to have fun. And what's all this about "proper planning"..... you get in the water, you swim around and you come out at 50bar. That sounds like a plan to me. It might not work for JJ but it works for millions of other divers.



That works fine, until you are on a liveaboard and doing 5 dives a day. Every diver will eventually want to plan a dive. Even if you don't plan, the simple fact is that your brain is a much better computer than the one on your wrist.





4) Dive computer programmers often play games with computational process so that they can take insulate themselves from the risk of taking largely square profile data and utilizing it on a multilevel dive. These games tend to result in odd and often ridiculous levels of conservation.


Better safe than sorry. I don't see the problem here.



There is no problem as long as you don't have any reason to push things. However, when you go on that liveaboard trip, you'll want to maximize your diving. It's far better to know where to stand, than to push against some invisible line somwhere.





5) Dive computers are expensive and in some cases leave divers with limited resources carrying equipment that is of far less benefit than other equipment that may have been purchased.


How much does that fancy Halcyon rebreather cost that JJ rides? And all those scooters? Jeeez. For the money he spends on *fills* a typical diver could buy a new set of gear every year. A computer is a drop in the bucket. And frankly if someone want to spend money on a computer instead of fancy tekky-toys, who is JJ to judge?



I think you are being a little bit disingenous here, so I'll just let it go.





6) Dive computers significantly limit the likelihood that divers will
track their residual nitrogen groups.


So what? The computer tracks them. That's what a computer is *for*. To take your mind off of these details.



Until your computer fails, and you sit out for 2 days, or worse, your battery contacts have a poor connection and after 4 days of heavy diving your computer thinks it's the FIRST dive again. This actually happened to a buddy of mine, but because he's an exceptional diver he immediately noticed that the times the computer were giving him were unrealistic. Don't stake your health on some electronics surrounded by salt water.

I don't know if I would call this "details", but if it is, then 'the devil is in the details'





7) Dive computers do not allow for Helium diving in any formats but the bulkiest and most questionable format.


And that's a damned good thing too because if it accounted for helium most divers would be paying functionality they *really* don't need.



Yes, no one needs a computer that can do helium. However, anyone diving below 80 fsw or so should definitely dive Helium. Just my opinion, you understand.





8) Dive computers will often generate longer decompressions than could be figured by an astute, well educated diver with experience.


Who cares. PUddlestompers don't do deco.



Yeah, until they get in trouble somehow and end up having 8 minutes of deco showing on the computer. More likely than not they'll race for the first stop that the computer indicates, which is at 20 fsw. Now that's REAL healthy.





9) Dive computers often create confusion by giving the user to much useless information, sometimes even obscuring depth and time in favor of blinking CNS and/or deco limitations.


No they don't. Maybe some of them do but not the good ones. This is simply untrue. Maybe JJ has trouble with them because in terms of computers he's a newbie.



That's really funny, I almost drenched my monitor! Actually, most computers that I know of display the NDL time in much larger numbers than the dive time, so I'd have to say JJ is right on this one







12) Dive computers do not offer divers as much flexibility in the
generation of profiles with varying conservation. For example the right mix would allow 100 min at 60 vs 60 at 60 but I might prefer to do one or the other and indeed might like a compromise. Computers confuse this issue by not providing divers with the proper information.


Mix? What's that? is like Air because that's what puddlestopmers dive with. Who cares about all these bells and whistles. Most divers don't need or want them.



Plenty of divers use nitrox. Air is great though, it gets me to the dive site. I put it in my tires.





13) Dive computers users often ignore table proficiency and therefore do not learn tables properly. When confronted with a situation where they can't dive the computer (failure, loss, travel etc) these divers are at a serious handicap.

Table proficiency? Many puddlestompers don't learn the tables well enough to use them a month after they're certified. For better or for worse the computer has become and will remain an essential piece of dive gear. It's like a buoyancy controller. BCD's never used to be standard gear either but people adopted them because they work and it makes diving easier and more fun. Anyone out there still dive without one? I see JJ has one.

The point is (yes, I am going to spell it out) is that JJ (et al) take their paradigm and project it onto everything and everybody but their paradigm doesn't fit everything and everybody. Doing so sounds as rediculous to me as saying "oh. just take your al80 and swim 5km into a cave with it. You should be ok as long as you're out with 50 bar". The puddlestomper paradigm doesn't fit JJ either. These are two different worlds with two very different sets of rules.

R.. [/B]

The difference is that if you listen to JJ you will have more fun, you will dive more, and you will have less fear in the water. It's not about forcing everyone to become a cave diver. It's about common sense.

For example, being horizontal in the water makes more sense than being vertical. Why? Well, when you are diving you want to minimze up and down movement, while encouraging forward movement. When you are vertical in the water, it's really easy to go up and down, there is no resistance. Going forward, however, offers lots of surface area for the water to push against. Being horizontal in the water isn't just about silting out a cave or not....it's EASIER!

Using a long hose on your primary, and dontating it in case of trouble, is the same thing again. Yes, it's very useful in a cave, when you have a restriction and have to go single file, blah blah blah. But guess what, when you're out of air it's much nicer to have a nice long 7 ft hose that you KNOW has got a working reg on it offered to you, as opposed to a 30" hose with a piece of &$^$ at the end that is probably full of sand. It doesn't matter if you're in a cave or not.

Knowing how to clear your mask is very important in a cave, but next time you buddy up with a moron and he kicks the mask right off your face, you'll be glad you learned that skill.

Etc. etc. etc.

PS No offense, everyone can dive the way they want to, I really don't care. But the arguments for diving the way JJ outlines are solid. Ignore them if you like.

[roturner]

[QUOTE]Braunbehrens once bubbled...
I'll add a rebuttal to your rebuttal. Soon we'll be swimming in butts.

Just kidding, thought I'd elaborate on a few points:


I'll just preface this by saying that there is a difference between the way I dive and my advocacy of puddlestoming. I think puddlestomping is a valid paradigm for diving (not necessarily for me, although I will admit to a certain amount of puddlestomping, as most divers probably would if they didn't worry so much about others laughing at them - I don't care) and not everyone wants to become a serious diver.


Every single dive you do is a deco dive.


I hear this a lot but I'll add that staying within your NDLs, if you want to call that a deco dive, is a very *different* kind of deco dive than it is when you overstay your NDL's. JJ's point was about planning. When you're planning on overstaying your NDL's you need JJ's type of planning. Anything less is sloppy at best and potentially dangerous. Puddlestompers, however are made to be afraid of their deco limits. That's why NDL is often in the middle of the screen. A puddlestomper has enough information in knowing 2 bits of information. (1) Am I within NDL's? and (2) what is my pressure. You can make a million safe dives in the puddlestomp paradigm without ever looking at your depth or bottom time. Issues such as zigzag profiles and fast ascents are definite worries but in the future you'll see computers getting more clever to adjust the NDL's down when divers make deco-unfriendly profiles. YOu wait.


<snip>
Even rec divers can benefit from understanding how deco works, and how to properly ascend from any dive.


You'll get no argument from me on that. But the fact is that a lot of divers don't care aobut how deco works. And everyone is trained to make slow ascents. If puddlestompers followed their OW training to the letter their dives would be very safe. And frankly, we're talking about a marginal issue here as far as safety goes. 60% of fatal incidents involve buoyacny prpoblems and 30% OOA. Most undeserved hits can be attributed to fast ascents which is in turn either panic or buoyancy issues. The root problems are clear. Understanding deco is a marginal issue but getting buoyancy under control and watching guages better are big safety issues. If we want to make the world safer for puddlestompers then we'd focus on their problems. And frankly they're not laying awake at night worrying about having or not having a computer. A computer has become required gear in the puddlestomper paradigm and I'd submit that like it or not we're not going back.


That works fine, until you are on a liveaboard and doing 5 dives a day.


I'd be willing to venture a guess that more divers get whacked on these kinds of trips than from all other kinds of activities combined. I think it might be time to introduce the topic of computre useage and aggressive multiple profiles at the OW level. I don't think taking away the computer is a realistic option even if doing so might make these profiles safer.


Every diver will eventually want to plan a dive.

I'm not so convinced of that. To a true puddlestomper jumping in, riding the computer and aborting with 50 bar *is* a plan. Following the DM around so you don't get lost is part of the package.... What a puddlstomper needs more than planning skills are navigation skills so when they finish the dive they're about where they started. Just 2 days ago I made an hour long dive at a site where I had never been before. I navigated (and I'm good at it if I do say so myself). We swam about 600-700 meters in 3 metre visibility and we finished the dive after an hour just a few metres away from where we started. Beginners and many puddlestompers can't do that. If they could then the whole ride-the-computer-and-abort-at-50-bar type of planning wouldn't be such a big deal.


There is no problem as long as you don't have any reason to push things. However, when you go on that liveaboard trip, you'll want to maximize your diving. It's far better to know where to stand, than to push against some invisible line somwhere.


I agree with you on this point. I think aggressive multiple-profiles need some attention from the very beginning.


Until your computer fails, and you sit out for 2 days, or worse, your battery contacts have a poor connection and after 4 days of heavy diving your computer thinks it's the FIRST dive again. This actually happened to a buddy of mine, but because he's an exceptional diver he immediately noticed that the times the computer were giving him were unrealistic. Don't stake your health on some electronics surrounded by salt water.


OK, you put your finger on an interesting point. We tend to assume that the computer is infallible. It's good to have an idea of what's realistic or not. Some people got bent because of the older Alandins too because they didn't have feeling for what was right. I don't have an easy answer for this in puddlestomper world. Personally I've been diving for 19 years and I've done a lot of diving on the tables so I might notice something like that but for the "blind reliance" crowd with no experience on tables this could potentially problematic. It's also a marginal issue if compared to the incident stats but for the one who gets whacked I guess that doesn't matter.


Yes, no one needs a computer that can do helium. However, anyone diving below 80 fsw or so should definitely dive Helium. Just my opinion, you understand.

Ok. We'll have to agree to disagree about this. I don't have a big problem with the 40 metre limit on air.


Yeah, until they get in trouble somehow and end up having 8 minutes of deco showing on the computer. More likely than not they'll race for the first stop that the computer indicates, which is at 20 fsw. Now that's REAL healthy.

Not doing it could be worse. Computers generate bad deco profiles but at least they give the puddlestomper in problems something that's better than nothing, namely a ceiling. A puddlestomper will, by definition, always go unplanned into deco. I've nevre seen computer user plan for this contingency. We used to do it every time we got in the water before we had computers but somehow the computer makes people think that this isn't necessary any more.


That's really funny, I almost drenched my monitor! Actually, most computers that I know of display the NDL time in much larger numbers than the dive time, so I'd have to say JJ is right on this one

:) Well.... my computer might not be typical but the current depth is front and centre on my screen. however; even if that's not the case, the puddlestomper's main goal is to avoid the NDL so putting the NDL in the middle of the screen isn't such a bad idea if you ask me. As I said above a true puddlestomper only needs to know pressure and NDL (countdown to zero).


Plenty of divers use nitrox. Air is great though, it gets me to the dive site. I put it in my tires.

LOL. :)


The difference is that if you listen to JJ you will have more fun, you will dive more, and you will have less fear in the water. It's not about forcing everyone to become a cave diver. It's about common sense.


Why on earth would you have more fun? I'll agree with you that if you want to become a serious diver and if you want to progress beyond underwatre tourism that you need to develop some skills. Primary among them in my mind are buoyancy control, alertness and navigation. This discussion seems to revolve around alertness. Where we agree is that a diver needs to develop it if they want to progress as a diver. We disagree about the roll the computer plays in this. I can follow that you say computer make divres lazy and unalert (I dove with tables for many years too and I can definitely see the difference). My point is that alertness can be trained by divers who use a computer and given the benifits of computers we are never going to get rid of them so we'd better find a way to make it work within the puddlestomper paradigm.


For example, being horizontal in the water makes more sense than being vertical. Why? Well, when you are diving you want to minimze up and down movement, while encouraging forward movement. When you are vertical in the water, it's really easy to go up and down, there is no resistance. Going forward, however, offers lots of surface area for the water to push against. Being horizontal in the water isn't just about silting out a cave or not....it's EASIER!


uhhh... yeah. but I don't quite understand what this had to do with the evils of computers. I agree with you but being a puddlestomper by no means mandates bad posture in the water.


Using a long hose on your primary, and dontating it in case of trouble, is the same thing again. Yes, it's very useful in a cave, when you have a restriction and have to go single file, blah blah blah. But guess what, when you're out of air it's much nicer to have a nice long 7 ft hose that you KNOW has got a working reg on it offered to you, as opposed to a 30" hose with a piece of &$^$ at the end that is probably full of sand. It doesn't matter if you're in a cave or not.


I agree. The longhose and necklaced octo is one of the few things about DIR that I wish would become standard.


Knowing how to clear your mask is very important in a cave, but next time you buddy up with a moron and he kicks the mask right off your face, you'll be glad you learned that skill.


Everyone learns this skill. You don't have to be DIR to know how to clear a flooded mask. You're not giving credit where credit is due.


PS No offense, everyone can dive the way they want to, I really don't care. But the arguments for diving the way JJ outlines are solid. Ignore them if you like.

Of course they are but I responded to a post about the evils of the computer. My point is (and it always is when i talk about puddlestompers) is that there are several valid paradigms for diving and puddlestomping isn't subject to the same logic as extreme caving. Puddlestompres are also not independent, secure and skillful divers by JJ's measure either but they don't want to be, they don't have to be and they aren't going to be. Some people just want it to be a simple as possible so they can have some fun. Their horizon is limited but who cares? I don't understand why people make such a problem out of this.

R..

[Charlie99]

Braunbehrens once bubbled...
That works fine, until you are on a liveaboard and doing 5 dives a day. Every diver will eventually want to plan a dive. Even if you don't plan, the simple fact is that your brain is a much better computer than the one on your wrist.
.... .....
Plenty of divers use nitrox. Air is great though, it gets me to the dive site. I put it in my tires.The "brain is much better computer than the one on your wrist" ranks right up there for trite sayings with "air is for tires". Your brain only gets decent results if you have a good algorithm, and so far I haven't seen the anti-computer guys offer any reasonable one. The closest is Uncle Pugs, but that is unreasonably conservative for my diving style.

Please give a general description of your dive planning while on a live aboard, or otherwise doing 5 dives a day.

TIA,

Charlie

[roturner]

Charlie99 once bubbled...
The "brain is much better computer than the one on your wrist" ranks right up there for trite sayings with "air is for tires". Your brain only gets decent results if you have a good algorithm, and so far I haven't seen the anti-computer guys offer any reasonable one. The closest is Uncle Pugs, but that is unreasonably conservative for my diving style.

Please give a general description of your dive planning while on a live aboard, or otherwise doing 5 dives a day.

TIA,

Charlie

What's obvious is that computers are much better at calculating multilevel profiles on the fly than your brain. He does have a point that having a computer is not a substitute for thinking about what you're doing.

R..
P.S. He uses a computer too. He just does it on the PC and copies the results onto a slate for reference under water. You lose something in flexibility but you gain something in predicability and if I believe him then (highly) diciplined plan-your-dive-and-dive-your-plan diving is more fun than riding the computer. The fact that this is an apples-and-oranges comparison is conveniently ignored much of the time.

[Charlie99]

roturner once bubbled...
What's obvious is that computers are much better at calculating multilevel profiles on the fly than your brain. He [Braunbehrens] does have a point that having a computer is not a substitute for thinking about what you're doing. If the statement "one should understand what one's computer is doing", then I agree. Computers are bad; Computers rot yer brain; You shouldn't use a computer are all statements that I disagree with in the context of recreational NDL diving.

This whole computer issue is yet another one of these cases of misapplication of tech diving style to rec diving. Other common misapplications I've seen are "jacket BCs are dangerous", and "Air is for tires". At least on this forum I haven't yet seen the "you are an idiot if you use a yoke rather than DIN". While one may argue advantages of BP/wings, nitrox, DIN valves, helium at 80', it is NOT true that those impose unacceptable risks in rec NDL diving.

I don't think DIR divers are so narc'd at 80' that the additional info on the computer (NDL) will confuse them. Simply pick a computer that, like most, displays NDL, runtime, and current depth on the main display.

What I don't understand is how the additonal information and the ability to compare your mental on-the-fly calculations with those of a computer increases risk. You learn by experience. Doing a dive, being aware of your profile, and comparing it with what the computer says is an excellent way to learn.

The context of my statement is recreational NDL diving, where gas planning is simply starting your return and ascent with sufficent margin.

Any DIR diver is welcome to explain how they handle multi-dive multi-level calculations on a liveaboard. "Take a DIR-F class" is not an appropriate answer.

Charlie

[Braunbehrens]

Sorry, Charlie, but I'm not going to do deco lessons on the 'net. Just doesn't make sense.

You want to use a computer, air, yoke, etc, etc, fine. I have no problem with it.

As for what skills are necessary and taught...when I took my padi classes we knealt on the sand, removed and replaced the mask. I hear that the current standard calls for simply flooding and clearing the mask, still while kneeling in the sand.

Is this really appropriate?

As for safety, diving is about as safe as riding a motorcycle, according to some figures I've seen. I think it could be much safer if a little more attention was paid to what is taught.

The question is not "can you dive with a computer, air, etc. etc.". Undoubtedly you can, and people have been doing it for a long time. The point is that all this stuff increases your risk, so why do it?

Are computers here to stay...well, you guys might well be right on that.

BTW, I do NOT write a plan onto a slate or anything like that. I carry a simple set of tables that take 2 pages in my wetnotes and cover ALL my diving, and ALL my gasses. I know when I'm coming up against serious (as opposed to minimum) deco, and if that happens I simply check my wetnotes at the first stop and figure out what I need to do.

I completely agree that the computer issue is less important than some of the other issues, like the long hose (possibly the most important), in water trim, buoyancy control etc. I also agree that the computer issue is largely a lost cause.

[roturner]

Braunbehrens once bubbled...
<snip>

BTW, I do NOT write a plan onto a slate or anything like that. I carry a simple set of tables that take 2 pages in my wetnotes and cover ALL my diving, and ALL my gasses. <snip>


I've heard others say this too but so far I haven't come across anyone willing to explain it. Care to indulge us?

R..

[Braunbehrens]

Rotourner, don't take this the wrong way, but no. I don't think it's appropriate for me to give out info that someoene could use to get in real trouble if they misunderstood it.

I can tell you basically what is behind it.

1) A proper understanding of deco. This includes deep stops, air breaks, and so on.

2) A set of tables

3) Some analysis of what a deco program will tell you and what the tables say.

4) Some rules of thumb to modifiy the tables so they "fit" 1 and 3.

5) Experimenting in the water. If you don't feel good after diving (tired, etc.) then you probably need more deco. Adjust 4 to suit.

6) Be here now. Be aware of what is going on, what depth you are at, how long you've been at this depth, what your gas consumption is etc. etc.

I just thougth of a good analogy. Imagine a hiker, going off for a long trek. He walks without paying any attention to how much water he needs, where he's going, if he's on a hill or in a valley, but once he's reached his limit, he grabs his GPS, and heads home.

The other hiker is making sure he has enough water, pays attention to whether he is on a hill or in a valley, and checks his direction using available information from his surroundings. He knows how many hills he has to climb to get back, how much water he has, and how long it will take him. He doesn't NEED GPS, he has more fun, and he is much safer.

[roturner]

Braunbehrens once bubbled...
Rotourner, don't take this the wrong way, but <snip>

Whatever. Take your ball and go home then if it makes you feel big and important. This kind of B.S. disappoints me to no end.

R..

[GreenDiverDown]

Braunbehrens once bubbled...
Rotourner, don't take this the wrong way, but no. I don't think it's appropriate for me to give out info that someoene could use to get in real trouble if they misunderstood it.



I suggest that you don't bring up a topic that you can't explain. Doing so makes it sound like you don't know what you're talking about.

You seem to be perfectly fine with explaining in painful detail other things that "someone could use to get in real trouble if they misunderstood it."

Maybe you shouldn't talk about those things either.


Sorry...I just get real tired of that excuse when this topic is brought up. Everything we talk about here carries the risk of being misunderstood. So explain it well and then leave behind an "intended only for the purpose of discussion and not meant to be used as instuction" message.

I'm beginning to wonder just how much "more fun and safe" your method can be when it's so complicated that you can't even explain it... and then hide behind that lame excuse we've heard again and again.

Come to think of it..."more fun and safe" is getting old! You need some newer and snappier catch phrases.

SA

[MikeFerrara]

I've argued this a lot on this board. Yes, they say you don't need a computer. But...if you ask why they say take a DIRF. But...they don't teach much of it in DIRF and some haven't been tought anything on it in DIRF. What they mean is they don't need a computer I guess.

I sometimes dive with a guy who is GUE tech 2 and cave 2. He doesn't have two pages of wet notes that cover all his diving. He runs the deco software, glances at it and goes diving without writting anything down. NOTHING!

I've gotten better at it and for some dives don't write anything down either. For other dives I write down a couple of schedules. I have not simplified it to the point that I can write two pages of wet notes to cover all my diving. I can, though, write two pages that will cover most of my diving.

I think what Braunbehrens is trying to tell you guys is that if you know what kind of deco you want to do and how it fits the profiles and gasses you dive that you don't need a computer to do it. Pay attention to what he writes. He repeatedly points out that deco isn't the exact science some think it is. I think he is right.

Read the points he listed above. Much of it is taking an educated guess based on decompression knowlege and past experience. It does work. There is no single magic GUR formula that can be learned in a day that frees you from the computer for all time.

By all means Paul correct me it I'm wrong.

My point has always been that the average recreational diver isn't going to do it. They won't spend the time to learn the deco methods. DIRF won't teach you and not every one wants to go to cave 2 and tech 2.

[Charlie99]

Braunbehrens once bubbled...
Sorry, Charlie, but I'm not going to do deco lessons on the 'net. Just doesn't make sense. .....
Braunbehrens further bubbled...
Rotourner, don't take this the wrong way, but no. I don't think it's appropriate for me to give out info that someoene could use to get in real trouble if they misunderstood it.
Hmmm. That doesn't seem to stop you on any other question. Perhaps you don't really have an answer. Perhaps your system works for the diving you do, but that diving has never included a liveaboard trip with multiple dives per day.

Various agencies other than GUE are open about their courses and have books available. The DIRF manual has no information regarding calculating multilevel dives, other than advising divers to avoid computers. 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.

Re your hiker analogy: I see the DIR attitude as the hiker saying "I don't need no stinking compass or GPS, I pay attention to where I am". A prudent hiker brings a compass, maps, and knows how to take advantage of a GPS while not relying upon it exclusively.

[Charlie99]

MikeFerrara once bubbled...
I've argued this a lot on this board. Yes, they say you don't need a computer. But...if you ask why they say take a DIRF. But...they don't teach much of it in DIRF and some haven't been tought anything on it in DIRF. What they mean is they don't need a computer I guess.


I think what Braunbehrens is trying to tell you guys is that if you know what kind of deco you want to do and how it fits the profiles and gasses you dive that you don't need a computer to do it. Pay attention to what he writes. He repeatedly points out that deco isn't the exact science some think it is. I think he is right.

Read the points he listed above. Much of it is taking an educated guess based on decompression knowlege and past experience. It does work. There is no single magic GUR formula that can be learned in a day that frees you from the computer for all time.
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.

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.

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.

[Braunbehrens]

Mike, you are dead on!

The rest of you guys are pretty funny. I give a DETAILED account of how to proceed, but you want everything served up on a silver platter. Give me a break!

This is EXACTLY why I'm not going to serve it up. You don't want to take the time to understand why these rules apply, you just want to know what they are. That's just how you get hurt.

Ironically, that is also what you guys always criticize about DIR. "You guys just blindly follow what Trey says..."

Well, I'm sorry to disappoint you, I don't blindly follow anyone, and I'm not going to make it easy for anyone else either.

You want to do deco without a computer? Then LEARN about deco. You don't have to take a GUE class to do it, just talk to some people (like Trey, or MHK, or Dr. Deco), and/or read some of the research, use some common sense, take a look at some deco programs and do some dives.

I'll even get you started. Take your favorite deco program and run a bunch of tables using air. Then run the same program using O2 for deco at 20. Notice anything? If you do, and it always works, do you really need to use a computer or carry tables for air and for O2? (I'm just using air as an example here).

Remember also that we use a limited number of gasses. You will never learn anything if you continually use a hundred different gasses. If you stick to a couple bottom mixes and a couple deco mixes everything clears up.

The problem is that all this stuff hangs together. You can use this small part and that small part, but in the end you can't be sure that the whole system works, unless it's been tried out. I know of only one such system that has been extensively tried out.

I don't know why I even bother....and people say the DIR crowd is unfriendly! I should put together a collection of the replies I get from the non-DIR people.

Try to keep it friendly please. We are all just divers trying to have fun...

[jonnythan]

Charlie99 once bubbled...

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.

I'm glad I'm not the only one who feels that way.

I suppose you could use some software like GAP to plan your non-deco repetetive dives for the day, but the problem is that they allow no deviation. If you and your buddy have 1200 psi of air left at 30 feet where you planned to have 900, so you want to spend an extra 5 minutes, you couldn't because it would screw up the rest of the diving that day and you'd have to run the numbers again.

The no computer thing makes sense for deco dives or dives that are goal-oriented.. the "mission" dives.

It just doesn't make any sense for the "checking out the wreck at 45-60 feet til we hit our rock bottom gas" dive followed by "swim around the helicopter at 35-55 feet" dive or "check out the reef, staying above 60 feet" dive.

[GreenDiverDown]

Well, PB...

I am actually very much pro DIR, so much so that it is one of the main reasons that I have given up teaching basic open water. In fact, it has changed my diving in every way...and in some ways not for the better. My problem with you is that in my opinion you are a poor DIR representative and actually do more bad than good for DIR...well... at least here on the board.

And as far as computers go... most of mine live in guage mode and I use tables most of the time...ah...rec diving only, by the way. Sometimes I do use a computer. But I also follow the rules of computer use, do reasonable and appropriate profiles, and have appropriate surface intervals. I have fun and I feel that I'm pretty safe.

I'm not ready to condemn the use of computers and I think many rec divers can benefit greatly from their use.

Oh, BTW, I have never had anything served on a "silver platter".
I've worked HARD for everything I have...including my skills and knowledge related to diving. Actually, I don't think I want anything from you.

But it would be nice to discuss DIR dive planning just like we discuss other things. It's just wierd that everytime the topic comes up it gets an immediate... shishh. I say it's about time that we talk about it.

SA

[Charlie99]

Stephen Ash once bubbled...
But it would be nice to discuss DIR dive planning just like we discuss other things. It's just wierd that everytime the topic comes up it gets an immediate... shishh. I say it's about time that we talk about it. If it's not "shissh", it's a rapid change of subject. I am trying to converse about why computers are, or are not appropriate for multilevel, repetitive NDL diving using a single gas, with AL80. PB, in his last post starts talking about deco at 20' with O2. Jeesh.

To be very clear, I am inquiring about ways of tracking and calculating NDL on repetitive multilevel dives, using AL80 tanks with a single gas. IF you DON'T choose to track NDL, and just have general rules that will ensure that you have completed deco by the time you get out of the water, just say that.

When someone makes a statement that computers are inappropriate for a particular use, it would be nice to find out what they think IS appropriate.

I guess for some DIR guys, listing a bunch of platitudes is easily confused with dishing things out on a silver platter.

PB tells me to learn about deco. Interesting statement, Paul. You don't know me. What I do know about deco might surprise you.

Charlie

p.s. My bailout tables for rec diving are very small, just a 3"x4" extract of DCIEM NDLs, and limits for 5, 10, 15, and 20 minute deco -- just 50 numbers total.

For multilevel predive planning, I use an enlarged printout of the backside of PADI RDP (RNT table), with all of the SI information of the other side replaced by a row of numbers I have added across the bottom of the RNT table. The multilevel dives are treated as multiple dives, with "0 SI".

As for repetitive diving, the tables use the 60 minute compartment as the controlling factor, my computer uses reciprocal offgassing while submerged, but has 60 min credit control upon surfacing, so the computer and tables track fairly closely. It is also a trivial matter to compare a few predicted NDLs by the computer and compare that to what the table assumes at that same SI time.

(See PB -- it IS possible to give a general description of a method used, without giving out info that can get people into trouble).

[Braunbehrens]

Stephen Ash once bubbled...
Well, PB...

My problem with you is that in my opinion you are a poor DIR representative and actually do more bad than good for DIR...well... at least here on the board.


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.

[Braunbehrens]

Charlie99 once bubbled...
What I do know about deco might surprise you.

Einstein was once giving a speech in front of a group of housewives. At one point, one of them asked him if he could explain the theory of relativity. Before answering, he asked the woman if she could explain to him how to make a cake. She said yes, she could. He then asked if she could explain to him how to make a cake if he didn't know what an egg is.

My point is not that you, Charlie, don't know anything about deco, or that I'm a genius - I'm not. My point is that this stuff gets archived, and anyone can read it. I'd have to start explaining all kinds of stuff just to get to the good bits. It's just not reasonable to ask me to do this on an internet forum. I am not an instructor, I am not an authority on deco, and what works for me might not work for you.

I have given you the pencils, the rulers and the aerial photographs, but you guys keep asking me to draw the map. I can't and don't want that responsibility. Draw your own map.

I use basic set of rules and a few tables and this covers all my diving. It's all very very simple. Deco is not an exact science. It works for me.

I won't give you my cheat book, but if you have specific questions I'd be happy to answer them to best of my ability. I am NOT an authority on this, just a guy who took a class and did a little (not a lot) of reading.

[Charlie99]

Braunbehrens once bubbled...
I won't give you my cheat book, but if you have specific questions I'd be happy to answer them to best of my ability. I am NOT an authority on this, just a guy who took a class and did a little (not a lot) of reading.

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

[roturner]

[QUOTE]Braunbehrens once bubbled...
Mike, you are dead on!

The rest of you guys are pretty funny. I give a DETAILED account of how to proceed, but you want everything served up on a silver platter. Give me a break!

Give ME a break. I ask you a question about dive planning and you answre me with some kind of absurd story about hiking in the woods and drinking water. You played the " knowledge is power " card and lost my respect. I would *never* take a course from an instructor who plays the "knowledge is power" card. No sane individual would.


This is EXACTLY why I'm not going to serve it up. You don't want to take the time to understand why these rules apply, you just want to know what they are. That's just how you get hurt.


what a crock. Why the hell do you think people ask these questions? The fact that you can't seem to answer that says more, much much more about you than the people asking the question. And don't get me wrong (to use your own words) we don't think you're an arrogant SOB. <big smile>

how on earth are you *ever* going to get people to take DIR seriously when you act like this? I actually gave you the benefit of the doubt. My mistake.


Ironically, that is also what you guys always criticize about DIR. "You guys just blindly follow what Trey says..."


NO, people believe this because Trey only leaves room for obedience. If he told you the moon was made of cheese you'd teach it to everyone. That's one thing that PADI does much much beter than GUE. At least the things PADI says are based in fact and supported by scientific study. All you have to go on is "Trey says so". Don't belive me? Remember the artical on deco procedure he wrote when he said (quote is approxmiate) "if you want to refute me then you'd better show me your log book because I've done this more often and better than anyone else and I won't believe anyone unless your log book can convince me".

Nice clean scientific underpinnings there.

Add to that, the GUE's obsession with supressing information about incidents among their members and you're starting to raise some major question marks in Rob's mind.

Remember JJ's letter about Steve Berman? Steve wasn't GUE but JJ was willing to essentially pubicly walk over the bones of his dead friend to protect the GUE. it was totally unnecessary aside from tasteless and immoral. Anyone who cared already knew that Berman was TDI. How did you read that? The way the rest of the world did or the way JJ told you to?

And if you didn't conform you wouldn't be a GUE instructor. Full stop.


Well, I'm sorry to disappoint you, I don't blindly follow anyone, and I'm not going to make it easy for anyone else either.


Of course you do. Where do you keep your reel? On the butt D-ring? I suspect that you *used* to do but these days you keep it somewhere else. Where might that be? Maybe I should ask George. He'll know. And if he changes it again I know who will fall in line......


deco without a computer? Then LEARN about deco. You don't have to take a GUE class to do it, just talk to some people (like Trey, or MHK, or Dr. Deco), and/or read some of the research, use some common sense, take a look at some deco programs and do some dives.


It's all *so* dangerous that you can't even explain it but now your're saying "just go do some dives". You know what this reminds me of? Martial arts. In the 70s they had "magic moves" and "secret techniques", "finger of death" etc etc that were *SO* dangerous that you couldn't learn about them until you took a bunch of classes and paid them a whole sh*t load of money. Well. I sucked into it. I took 10 years of classes and I can tell you there *IS* no "finger of death". This B.S. that you're spouting now has a very familiar taste to me.

<snip>

Remember also that we use a limited number of gasses. You will never learn anything if you continually use a hundred different gasses. If you stick to a couple bottom mixes and a couple deco mixes everything clears up.


Ok. now we're talking. pull the skirt up a little higher.


The problem is that all this stuff hangs together. You can use this small part and that small part, but in the end you can't be sure that the whole system works, unless it's been tried out. I know of only one such system that has been extensively tried out.


Got that right. The only system that has been tried out extensively would be the Padi system :)


I don't know why I even bother....and people say the DIR crowd is unfriendly! I should put together a collection of the replies I get from the non-DIR people.


Perhaps looking into the reasons why you seem to evoke these reactions wouldn't be going too far either.


Try to keep it friendly please. We are all just divers trying to have fun...

I'm having trouble beliving you at this point. I suspect that your posts on Quest are much less sympathetic to your friends on scubaboard than you attempt to portray here.

R..

[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]

[SIZE=3][FONT=times new roman][COLOR=darkblue]

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?:confused:

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"?:confused: 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...
[SIZE=3][FONT=times new roman][COLOR=darkblue]


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.

[roturner]

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..

[BigJetDriver]

MikeFerrara once bubbled...


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. [SIZE=3][FONT=times new roman][COLOR=darkblue]

Actually, they (the point-source reports and predictions that we use for the landing fields) are generally NOT wrong, and if they err, the result is that the weather is usually BETTER than predicted. Also, if you have ever flown the North Atlantic in winter, you know that there are times when you'd practically be willing to sell your first-born to continue getting the real-time IR satellite shots to tell you where the weather actually is located!:)

Now as for checking the Weather Channel to find if one should take an umbrella to work...well...we all still use many grains of salt there!;)

As for defining the word "accuracy" in terms of decompression, that argument falls more into the realm of high-level mathematics than anything else. One of the best sources we have today is Dr. Bruce Wienke of the Los Alamos National Laboratory. He is a very personable and pleasant fellow, and quite willing to talk about his work in layman's terms. Because he is a diver, his work is well grounded in reality. His latest book, TECHNICAL DIVING IN DEPTH, goes into that subject at length. The math is included as proof of concept for those who understand it. For those who are not so mathematically oriented, there is enough verbiage to make his points clear in plain language. ;)

[Braunbehrens]

roturner once bubbled...
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:

I'm really sorry if I've somehow offended you, that was not my intention. I don't think you're a stroke, and I don't like to use that word.

I would be happy to answer any question to the best of my ability, short of giving you the rules I use for deco.

[jonnythan]

Braunbehrens once bubbled...


I'm really sorry if I've somehow offended you, that was not my intention. I don't think you're a stroke, and I don't like to use that word.

I would be happy to answer any question to the best of my ability, short of giving you the rules I use for deco.

It sounds like the methods you're describing come from a good understanding of and experience with decompression dives.

Is this the case, and do they teach that method in DIRF?

[Braunbehrens]

I don't know what they teach these days in DIR-F classes, I took mine in the early days. It probably somewhat depends on the makeup of the class.

I don't know how good my understanding of deco theory is...but there are a few things I've learned, and I use them in a common sense approach, along with some simple rules and some tables for a general reference.

When you do similar dives a lot you end up having a good idea of what is required. This is a huge advantage over using computers.

[Braunbehrens]

Deco is not an "exact" science. Otherwise no one would get bent following the the rules, but there are plenty of 'undeserved' hits.

It's a matter of understanding the right shape, doing the deep stops, etc. This applies to EVERY dive.

[roturner]

Braunbehrens once bubbled...


I'm really sorry if I've somehow offended you, that was not my intention. I don't think you're a stroke, and I don't like to use that word.

I would be happy to answer any question to the best of my ability, short of giving you the rules I use for deco.

Ok. I can't very well stay mad at you forever.

To start with I'm not after your deco rules. I'm not about to run off and apply the magic formulas and I'm neither reckless nor stupid enough to start experimenting with this kind of thing on my own.

However

I do want to know how the machine works. It's partly curiosity and partly so I can get a feeling if it's useful enough to consider taking a course. What I'm after is a big picture in enough detail that I can see how it all hangs together and so I can get an impression of it's utility in real diving.

I'm not quite sure where to start but lets start with your point that you need a different way to think about deco. Do you mean we need to forget Haldane?

As far as the tables go I'd like to know what kinds of informatoin are on the tables and why. For example, is it a list of M-values and 1/2 times at some kind of baseline pressure? That's the only thing I can imagine it being but I must be missing something because you'll need to have some kind of indicator of which compartment is leading.

This is the level of information I'm after. Let's just leave it at that for the moment so I can see if I'm going in anywhere near the right direction to start with.

R..

[jonnythan]

Braunbehrens once bubbled...
I don't know what they teach these days in DIR-F classes, I took mine in the early days. It probably somewhat depends on the makeup of the class.

I don't know how good my understanding of deco theory is...but there are a few things I've learned, and I use them in a common sense approach, along with some simple rules and some tables for a general reference.

When you do similar dives a lot you end up having a good idea of what is required. This is a huge advantage over using computers.

How do you do *any* dives outside the scope of a basic table without a computer?

[MikeFerrara]

BigJetDriver69 once bubbled...
[SIZE=3][FONT=times new roman][COLOR=darkblue]

Actually, they (the point-source reports and predictions that we use for the landing fields) are generally NOT wrong, and if they err, the result is that the weather is usually BETTER than predicted. Also, if you have ever flown the North Atlantic in winter, you know that there are times when you'd practically be willing to sell your first-born to continue getting the real-time IR satellite shots to tell you where the weather actually is located!:)

Now as for checking the Weather Channel to find if one should take an umbrella to work...well...we all still use many grains of salt there!;)

As for defining the word "accuracy" in terms of decompression, that argument falls more into the realm of high-level mathematics than anything else. One of the best sources we have today is Dr. Bruce Wienke of the Los Alamos National Laboratory. He is a very personable and pleasant fellow, and quite willing to talk about his work in layman's terms. Because he is a diver, his work is well grounded in reality. His latest book, TECHNICAL DIVING IN DEPTH, goes into that subject at length. The math is included as proof of concept for those who understand it. For those who are not so mathematically oriented, there is enough verbiage to make his points clear in plain language. ;)

Actually Bruce Wienke is a member of this board. We all know who he is. I have and have sifted through most of his book TECHNICAL DIVING IN DEPTH. However most of the good work he has done has been totally ignored by the folks who programmed your computer. Some of us however conduct out decompression in a mannor (or shape) that will resemble an RGBM profile far closer than what your VR3 will provide. Since your computer uses no "AI" and has no idea about how YOU felt after your last dive it is not able to learn as you can. The computer just spits out numbers based on calculations using measurements of depth, time and the buhlmann model. I personally know folks who have gotten very bent while their computer was very happy. While the measurements may be accurate and the calculations complex they still don't seem to accurately predict the outcome. I saw their profiles and I would do the same dive very differently and the computer would be of non help at all. I know how deep I am and how long I'm there. If I choose I can use max depth to calculate decompression or I can use the knowlege that I actually had a multilevel profile to modify it. I can also take advantage of past experience and better deco shapes using gradient factors (or whatever).

Now, I don't tell any one that they shouldn't use a computer. I never refer to myself as DIR and I'm not GUE trained but I have done some diving and know what lever of confidence I have (or don't have) in the gamoke who programmed the computer. I also know what I did on dives wher I didn't feel so good afterwards and what I did on dives that I felt great after. If you can find a computer that knows that stuff I'll pay double for it.

Then there are the advantages you find in simplifying dive planning by knowing ahead of time what your deco will look like. As far as I'm concerned a little extra deco isn't the danger it's the wrong deco.

Who knows maybe some day some one who understands diving will build a computer and I'll give it a try. In the mean time though I'll buy a lot of gas with the money that a multi gas trimix computer costs. I will also end each dive knowing that my ascent schedule worked well the last time I used it rather than hoping the computer spits out a surprise schedule that works.

[ERP]

OK I'm going to try and come at this from a different angle, I'm not DIR trained although the majority of my dives have been with a DIR trained buddy, and I do intend to take DIRF shortly.

Being the inquisitive sort I tend to ask a lot of questions and discuss things like the merits of a computers (and yes I dive one in computer mode).

It seems to me that the Computer/Non-computer proponents in this thread are arguing about different things, and I think that some of the message is getting lost.

It is my understanding reading this thread that the No-Computer proponents are trying to convey, is not that computers in and of themselves are bad, but rather that they don't tell the whole story, and reliance on a computer is a bad thing for this reason alone.

A computer doesn't control your profile, you do. A bad profile is a bad profile whether the computer says your inside the NDL or not.

All dives are deco dives, the only real difference is where you do the deco, in the water or out of it at 1ATA. With the right profile, you can feel much better after a dive.

DIR trained divers do not use computers, because even with rec like profiles the computers do not allow them to dive the profiles they find most effective without complaining (insisting on a 3 minute safety stop). And obviously on dives with planned deco, computers are not useful, because of gas switching and the algorythms in use.

If I'm misreading here, I'm sure someone will correct me.

[Charlie99]

Braunbehrens once bubbled...
I would be happy to answer any question to the best of my ability, short of giving you the rules I use for deco. Hmmm. Makes it difficult to compares different options.

This leaves the two options that are publically discussed on this board being:
1. Use tables
2. Use computers.

Once someone has low enough SAC that the tables become the limiting factor, computers are an attractive option.

It would be nice to discuss other options, but clearly that discussion will not be with you.

Charlie

[Braunbehrens]

Erp, you are right on.

Roturner, I just have a set of basic tables with only the long stops.

Deco is much much simpler than most people think it is. Just a few basic rules, get the shape and the general deco time right...the rest is propellerhead BS.

It's interesting to talk about all the compartments and how they are loading etc, etc, but the fact is that this knowledge is not enough to keep anyone from getting bent 100% of the time, so it's really only useful in terms of understanding what the general curve is supposed to look like. It's also insufficient at explaining why some people DON't get bent doing some really really stupid stuff.

All that fancy math is like trying to figure out the 8th decimal point of a distance that was arrived at by eyeballing an area the size of a football field.

As Mike says, take the deco program and play with it. For the same dive you can get wide changes in deco time, stops, etc etc. just by changing a few of the parameters. What does this mean? It means that you should find some values that work for you, adjust the shape so it is the right shape, take a few other simple rules into account, and go diving. Start with some conservative values, and go from there.

I know that people don't like George Irvine because he can be a bit harsh at times. However, he's posted a lot of good info about deco.

Again, I'm no expert, and I don't think you need to be one to figure this stuff out. Just play with this stuff, spend some time with it, try a few dives, see how you feel, don't push things until you are more comfortable...

I'm not all that happy posting even this much. I AM NOT AN AUTHORITY ON THIS! Do it at your own risk, and verify antything you hear from some yahoo on the internet (me) by more serious means (such as taking a class).

[Charlie99]

Braunbehrens once bubbled...
I know that people don't like George Irvine because he can be a bit harsh at times. However, he's posted a lot of good info about deco.He has postedc some interesting stuff on repetitive dives:
... http://www.wkpp.org/articles/Decompression/repetitive_dives.htm

[BigJetDriver]

[QUOTE]MikeFerrara once bubbled...
[B]

However most of the good work he has done has been totally ignored by the folks who programmed your computer.

Since your computer uses no "AI" and has no idea about how YOU felt after your last dive it is not able to learn as you can. The computer just spits out numbers based on calculations using measurements of depth, time and the buhlmann model. I personally know folks who have gotten very bent while their computer was very happy. While the measurements may be accurate and the calculations complex they still don't seem to accurately predict the outcome.....

__________________________________________________ __

Mike Ferrara,

I do know how I feel at the end of the dive, and most of the advanced computers on the market will let me reset the physiological and conservatism factors as I need to!

I have to believe that you did not read my original message. In it I did state that the VR3 does NOT utilize the RGB model. I sure would like to persuade Kevin to let the end user install that model if so desired. (if anyone has any influence in that sphere, I definitely would like their help.)

As for my original contention, I know of no one who is faster than a speeding microchip at these kinds of calculations. (If you are, I do suggest you apply at Professor Xavier's school. I will, however, wait for verification by people like Sawatzky, Wienke, and Vann before I believe it.)

And since you have, by your own account, read some of the literature, you know full well that on any given day YOU can be bent by what YOU do, just as easily as any other diver within any other "safe" profile.;)

[roturner]

Braunbehrens once bubbled...
Erp, you are right on.

Roturner, I just have a set of basic tables with only the long stops.

<snip>

You mean something like the navy deco tables? If that's your starting point then the rest would be to work out proper ascent rates, deep stops and your profile to get a deco procedure that works for you. Am I pointed the right way now?

How do you plan your gas? You'd need to have at least some idea of your profile before you start even if we assumed that your deco stations were surface supported (which is probably very un-DIR like). The reason I'm asking this question is because something you said a few posts ago made me think that you just go diving and work out your deco on the fly at your first stop. You could obviously do it with tables if you know where your first (deep) stop will be but there must be more to your planning than just jumping in.....

R..

[Richeod]

I don't have the time to get into a back and forth on this board but there are some things that need to be cleared up.

1st.

DIRF is NOT a deco class. Its purpose is to teach basic skills, dive planning, and the reasons why specific equiptment is used. On the fly deco is NOT taught. GUE does have a set of minumum deco tables (NDL's if you will). There use is covered. They teach things differently, i.e. averaging depth and an alternate way to plan repetitive dive times. They also do a series of 1 minute safety stops rather than the 3 at 15. The tables are designed to be easy to use rather than getting every last minute of bottom time. If after the class you want to use a computer for diving so be it. DIRF does not turn you into a DIR diver nor does it prepare you to join the WKPP. It just gives you the building blocks to enable you to continue further if you so desire.

2nd.

Tech 1 is where deco theory is introduced. Again GUE does things differently here. The tables that Paul caries are a set of ranged air tables cut with decoplanner. The GF's are set (to a standard setting) and away you go. The tables (about 3 pages in your wet notes) are carried and modified (in your head) depending on backgas used and deco gas used. It is very simple and easy to use. And that is as detailed as I am willing to get. Sorry, take a class.
On the fly deco is done differently, and also introduced in Tech 1. It is just that, ON THE FLY. You do it all in your head while you are diving. It is so easy as to be laughable, and it works VERY well. I have never felt better after a dive.
You DON"T just jump in the water without planning the dive though. You figure out how much you can do on the surface (based on gas) and use that as a maximum. Then you plan what you want to do.

Hope that clears up some of the confusion.

[Braunbehrens]

Since the cat is out of the bag, re. depth averaging, I'd just like to shove it back in ;-)

Well, no, but please don't just "average" your depth. That does not work! You have to get a feel for it, weigh things a certain way, be aware of your depth at all times, etc.

PLEASE don't use this stuff without taking a class or at least diving with someone who does it and having them show you. This is not something you pick up by reading a post on scubaboard.

P.S. It took some time, but all my minimum deco times, and deco tables fit on 2 pages, I even have room for a couple of other tables, such as a cheat sheet that helps when you have divers with different sized tanks.

And he's right when he says that it's so simple it's laughable.

Remember, deco is a large approximation, not an exact formula. Figuring things out to the minute is not going to help. It may make you feel better in your head, but it won't affect the likelyhood of you getting bent. If you want to reduce that likelyhood, add a few minutes to your deco.

[BigJetDriver]

Braunbehrens once bubbled...
Remember, deco is a large approximation, not an exact formula. Figuring things out to the minute is not going to help. It may make you feel better in your head, but it won't affect the likelyhood of you getting bent. If you want to reduce that likelyhood, add a few minutes to your deco. [SIZE=3][FONT=times new roman][COLOR=darkblue]

Help me to understand something here, please. Are you saying that the way to avoid getting bent is to estimate or take a "wag" at it, and just sprinkle in a few extra minutes to your deco?

[Uncle Pug]

BigJetDriver69 once bubbled...
Are you saying ... a "wag" at it
That isn't what he said.... and it certainly isn't what he meant.

[Braunbehrens]

Thank you Uncle Pug.

No, I'm saying that the way to avoid getting bent is to understand how deco works, and what works. Not by using some fancy gizmo.

The numbers in question are all crude approximations. However, the SHAPE of the deco and a few other things, are far more important.

For example, you mentioned (correct me if I'm wrong) that you drive some kind of rig that keeps you at a constant PO2. This is exactly what you don't want, if you understand deco. Rather than having your PO2 high on the bottom, where the risk and danger of tox is much higher, keep it low and offset some of that oxygen with helium, which is easier to deco from. Once you are shallow and doing deco, go for the maximum gradient by using a PO2 of 1.6, but don't stay on it. Take frequent low PO2 breaks. The reason for this is that your ability to offgas actually decreases when breathing high PO2's for lengthy time periods. Low po2 breaks will prevent this and your deco will actually be more effective.

Another reason to avoid high po2's on the bottom is that you only have so much "high po2 reserve". If things turn out really bad, and you need to hit the chamber, you'll be in deep trouble if you've exhausted this reserve! The treatment will be ineffective, and possibly dangerous.

I shouldn't even be saying all this, I'm not really the right guy to listen to on this subject. There are people who know a lot more, and understand this a lot better. Much has been written about it. I suggest you take a look at it. DO NOT DIVE BASED ON WHAT I SAY! DO YOUR OWN RESEARCH! Better yet, take a class. Sorry for the all caps, trying to keep it clear.

[Divesherpa]

Hey Paul,

What would be a big dive for you? I'm only referring to bottom times, depth, and total time in water.

Cheers and safe diving,
Jamie

[roturner]

Braunbehrens once bubbled...
Since the cat is out of the bag, re. depth averaging, I'd just like to shove it back in ;-)

Well, no, but please don't just "average" your depth. That does not work! You have to get a feel for it, weigh things a certain way, be aware of your depth at all times, etc.

PLEASE don't use this stuff without taking a class or at least diving with someone who does it and having them show you. This is not something you pick up by reading a post on scubaboard.

P.S. It took some time, but all my minimum deco times, and deco tables fit on 2 pages, I even have room for a couple of other tables, such as a cheat sheet that helps when you have divers with different sized tanks.

And he's right when he says that it's so simple it's laughable.

Remember, deco is a large approximation, not an exact formula. Figuring things out to the minute is not going to help. It may make you feel better in your head, but it won't affect the likelyhood of you getting bent. If you want to reduce that likelyhood, add a few minutes to your deco.

Ok, thanks for the explanation (also to Richeod).

R..

[BigJetDriver]

Braunbehrens and Uncle Pug, et al,

Okay, let's clear up some misconceptions here...
("SNIP" will be Braunbehrens--Numbered paragraphs will be my thoughts.)

(1) I asked the question to make sure I understood what your intent was. You and Uncle Pug explained. Thank you.

SNIP>No, I'm saying that the way to avoid getting bent is to understand how deco works, and what works. Not by using some fancy gizmo.>

(2) I could not agree more. If you are going to DO deco, you need to study and try to UNDERSTAND deco. It has been an on-going study of mine. (The "fancy gizmo" comment unfortunately makes you sound like one of those folks who said: "Ya wuddn't get me in one of them new-fangled ottymobeels!---insert chosen hated machine---)

SNIP>The numbers in question are all crude approximations. However, the SHAPE of the deco and a few other things, are far more important.>

(3) The numbers have ALL been crude approximations since the days of the old Goat-bender himself. Recently, however, doppler studies, chamber research, and computer analysis on a scale here-to-fore impossible (not to mention the work of some really sharp minds) have been changing the face of the map when it comes to deco. My question would have to be: "What, exactly, do you mean by the comment about the SHAPE (since you put it in capitals) of the deco?" Are you referring to the plot, or graph, of the deco times in specific situations? Or, as someone else suggested, is this one of these Dark Force Jedi mind-trick wave-of-the-hand kind of things? Or is it some emotional thing?

SNIP>For example, you mentioned (correct me if I'm wrong) that you drive some kind of rig that keeps you at a constant PO2.

(4) Correct. It is a Computer-controlled Rebreather. The O2 sensors and the logic system are set to read PPO2 in the loop and maintain it at one's requested set-point.

SNIP>This is exactly what you don't want, if you understand deco.

(5) Think about that for a moment. It is exactly what you DO want! As long as your PPO2 is within limits, maximising your oxygen fraction results in minimising your inert gas fraction (whatever that inert gas may be). Remember that you are dealing here with a (mostly) sealed system that can, unlike OC or SCR's, constantly change the fractions of your mix.

SNIP>Rather than having your PO2 high on the bottom, where the risk and danger of tox is much higher, keep it low and offset some of that oxygen with helium, which is easier to deco from.

(6) All correct. PPO2 must remain within safe limits. Also, helium has its hazards, but it is the best inert gas to choose for a lot of reasons. (I belong to the group known as the "Helium is my friend!" camp in the CCR community.)

SNIP>Once you are shallow and doing deco, go for the maximum gradient by using a PO2 of 1.6, but don't stay on it. Take frequent low PO2 breaks. The reason for this is that your ability to offgas actually decreases when breathing high PO2's for lengthy time periods. Low po2 breaks will prevent this and your deco will actually be more effective.

(7) The reason for keeping your PPO2 high (but still in the safe range) is, as you know, to steepen the off-gassing gradient and open that "oxygen window". The reason for taking air breaks is actually to keep your over-all exposure to oxygen within safe limits to avoid CNS O2 toxicity. The comment about your ability to off-gas decreasing is only true on the capillary level. Over-all, you need to maximise the gradient, and keep it there.

SNIP>Another reason to avoid high po2's on the bottom is that you only have so much "high po2 reserve". If things turn out really bad, and you need to hit the chamber, you'll be in deep trouble if you've exhausted this reserve! The treatment will be ineffective, and possibly dangerous.

(8) Unfortunately, you are a victim of a diving "urban myth" when you say what you have said above. I am not bragging here, but I want you to know that I do know what I am talking about when it comes to this. For some years, I have been a certified Diver Medic Technician. I am still current. I was trained at UTMB Galveston, by Dr. Richard Mader, a noted researcher in the field of hyperbaric medicine, and Kevin Corson (phone number on request if you wish to check), a well-known DMT Instructor of "oil-patch" medics in the Gulf of Mexico. I am still current. Trust me on this one. If you are in "bubble trouble" and you are brought to the chamber, we WILL still treat you EVEN if you have exceeded your PPO2 exposure limits. (Treatment will probably be with the Navy Table 6 treatment schedule.) An individual's tolerance to O2 exposure increases in the chamber environment for a lot of reasons. Even if you do convulse, however, that will NOT be life-threatening in the controlled environment. Leaving those bubbles alone and not crushing them back down to a manageable size will DEFINITELY limit your "well-ness" potential.

SNIP>I shouldn't even be saying all this, I'm not really the right guy to listen to on this subject. There are people who know a lot more, and understand this a lot better. Much has been written about it. I suggest you take a look at it. DO NOT DIVE BASED ON WHAT I SAY! DO YOUR OWN RESEARCH! Better yet, take a class. Sorry for the all caps, trying to keep it clear.

(9) Actually, I don't know why you feel you shouldn't be saying what you said. With a couple of exceptions (as noted), what you are saying is GOOD advice, especially your comments in this last paragraph. As you say, much has been written about the subject. I have read an awful lot of it, and in some cases, taken classes from, or spoken directly to the authors. I will continue to do so! As you say, do the research, take the classes, and, I would add, keep an open and enquiring mind!:) :)

[Uncle Pug]

BigJetDriver69 once bubbled...
My question would have to be: "What, exactly, do you mean by the comment about the SHAPE (since you put it in capitals) of the deco?" Are you referring to the plot, or graph, of the deco times in specific situations?
Since Paul is offline right now I will venture to answer for him:

Yes.

[Braunbehrens]

BigJetDriver69 once bubbled...
you sound like one of those folks who said: "Ya wuddn't get me in one of them new-fangled ottymobeels!---insert chosen hated machine---)



Honestly, I really don't care. I don't even care that much about "looking good" in the water. I'm interested in what works, and what keeps me well. Peer pressure has never been a strong factor in my life, I prefer to use my brain.





Recently, however, doppler studies, chamber research, and computer analysis on a scale here-to-fore impossible



Nope, it's still a crude approximation.






(5) Think about that for a moment. It is exactly what you DO want! As long as your PPO2 is within limits, maximising your oxygen fraction results in minimising your inert gas fraction (whatever that inert gas may be). Remember that you are dealing here with a (mostly) sealed system that can, unlike OC or SCR's, constantly change the fractions of your mix.



No. Keep your PO2 low on the bottom, and high during deco, with on/off toggling. There are several effects happening when breathing high PO2's. This will minimize them. The idea that you can keep your inert gasses low by raising the PO2 is putting the cart before the horse. What you are doing is infringing upon your high pO2 allowance while still on the bottom.




SNIP>Rather than having your PO2 high on the bottom, where the risk and danger of tox is much higher, keep it low and offset some of that oxygen with helium, which is easier to deco from.

(6) All correct. PPO2 must remain within safe limits. Also, helium has its hazards, but it is the best inert gas to choose for a lot of reasons. (I belong to the group known as the "Helium is my friend!" camp in the CCR community.)



Unfortunately people in that community have been sold on a very dangerous concept, and quite a few have paid the price.





SNIP>Once you are shallow and doing deco, go for the maximum gradient by using a PO2 of 1.6, but don't stay on it. Take frequent low PO2 breaks. The reason for this is that your ability to offgas actually decreases when breathing high PO2's for lengthy time periods. Low po2 breaks will prevent this and your deco will actually be more effective.

(7) The reason for keeping your PPO2 high (but still in the safe range) is, as you know, to steepen the off-gassing gradient and open that "oxygen window". The reason for taking air breaks is actually to keep your over-all exposure to oxygen within safe limits to avoid CNS O2 toxicity. The comment about your ability to off-gas decreasing is only true on the capillary level. Over-all, you need to maximise the gradient, and keep it there.




Actually, wkpp divers go far beyond the "safe limit"of PO2 exposure (like 10 times over). The reason is that this is again a poorly understood field, and our bodies don't work the way the models have been written...otherwise they would have all toxed a long time ago. The very fact that they are able to do this, shows that their method for dealing with high PO2's is superior to yours. No offense.




SNIP>Another reason to avoid high po2's on the bottom is that you only have so much "high po2 reserve". If things turn out really bad, and you need to hit the chamber, you'll be in deep trouble if you've exhausted this reserve! The treatment will be ineffective, and possibly dangerous.

(8) Unfortunately, you are a victim of a diving "urban myth" when you say what you have said above. I am not bragging here, but I want you to know that I do know what I am talking about when it comes to this. For some years, I have been a certified Diver Medic Technician. I am still current. I was trained at UTMB Galveston, by Dr. Richard Mader, a noted researcher in the field of hyperbaric medicine, and Kevin Corson (phone number on request if you wish to check), a well-known DMT Instructor of "oil-patch" medics in the Gulf of Mexico. I am still current. Trust me on this one. If you are in "bubble trouble" and you are brought to the chamber, we WILL still treat you EVEN if you have exceeded your PPO2 exposure limits. (Treatment will probably be with the Navy Table 6 treatment schedule.) An individual's tolerance to O2 exposure increases in the chamber environment for a lot of reasons. Even if you do convulse, however, that will NOT be life-threatening in the controlled environment. Leaving those bubbles alone and not crushing them back down to a manageable size will DEFINITELY limit your "well-ness" potential.


I'm not going to trade credentials with you, I'm sure you have more than me. However, I look to the people who are able to do the dives, and I think I understand what I read as much as the next guy. I also know people who have experienced problems from breathing O2.

Of course you are going to treat someone who is bent, that wasn't my point. The question is how effective the treatment is going to be, and what the consequences of the treatment are. The treatement will work a lot better if the guy hasn't been on high pO2's.

I don't really want to get into a back and forth....I know where you are coming from, and I am convinced that you you're not going to give up diving the way you have been.

People should go to the source and do the reading, as opposed to listening to two guys parroting stuff that's 3 times removed from the source.

[padiscubapro]

Braunbehrens once bubbled...


Honestly, I really don't care. I don't even care that much about "looking good" in the water. I'm interested in what works, and what keeps me well. Peer pressure has never been a strong factor in my life, I prefer to use my brain.


computer usage can be a plus with the right model and equipment.. I know you are against constant PO2 and computers but here is a profile I HAVE done, the explorer computer profile was almost exactly as planned (it actually cleared a few minutes ahead of my tables)..

300for 30 minutes at a constant PO2 of 1.30

first stop using RGBM is 220ft, total tts is 109 minutes, even including the bottom time this is still below noaa limits plus I can stay on He all the way up.. if I did a dil flush with a nitrogen/oxygen only mixture my TTS drops down to 99 minutes (I haven't tried this yet)

If you were on OC you would be have your first stop still at 220, but have a total TTS of 174 minutes with only about 10% less oxygen exposure..
this assumes swiches to 50% and 100% oxygen

if you use another intermediate gas say 32%oxygen and 32% helium (I dont remember the GUE recommended gas)as an intermediate step before the 50%, tts of 131.. Whats your "official" GUE profile

On my CCR I felt perfect after the dive

BTW from what I have told if this was an Ocean dive it would be against GUE recommendations since its longer than 90 minutes (not sure how true that is).

[BigJetDriver]

Braunbehrens once bubbled...


Honestly, I really don't care. I don't even care that much about "looking good" in the water. I'm interested in what works, and what keeps me well. Peer pressure has never been a strong factor in my life, I prefer to use my brain.

(My comment was not about you as a person, but about the tenor of your remark. If you took it personally, I do apologize.)


Nope, it's still a crude approximation.

(You are obviously not using the latest models, but if you are, and you still think it is a crude approximation, then you are participating in and advocating unsafe practices.)


No. Keep your PO2 low on the bottom, and high during deco, with on/off toggling. There are several effects happening when breathing high PO2's. This will minimize them. The idea that you can keep your inert gasses low by raising the PO2 is putting the cart before the horse. What you are doing is infringing upon your high pO2 allowance while still on the bottom.

(Uh, the usual set-point is 1.3. Did I miss something here?)


Unfortunately people in that community have been sold on a very dangerous concept, and quite a few have paid the price.

(If you are saying that helium is dangerous when utilized within MODERN deco programs, you had best go back to "Deep Air".)


Actually, wkpp divers go far beyond the "safe limit"of PO2 exposure (like 10 times over). The reason is that this is again a poorly understood field, and our bodies don't work the way the models have been written...otherwise they would have all toxed a long time ago. The very fact that they are able to do this, shows that their method for dealing with high PO2's is superior to yours. No offense.

(Let me get this one staight, you criticise some people for the way they use helium, yet in the next breath you say it is okay to violate every known medical and practical standard for O2 exposure by as much as, to quote you, "like 10 times over"?? Now that is a dangerous and irresponsible comment!)


I'm not going to trade credentials with you, I'm sure you have more than me. However, I look to the people who are able to do the dives, and I think I understand what I read as much as the next guy. I also know people who have experienced problems from breathing O2.

(I do as well, and those problems are known as CNS toxicity and "Whole Body" toxicity. Which, of course, is why there are limits and standards set by people with long years of study and practice in the field. They are those same limits that you just said it is okay to break ten times over!)


Of course you are going to treat someone who is bent, that wasn't my point. The question is how effective the treatment is going to be, and what the consequences of the treatment are. The treatement will work a lot better if the guy hasn't been on high pO2's.

(As someone who has participated in administering the treatment of which you speak, I can tell you that it WILL work the same way it is supposed to physiologically. It is just that the risk of CNS manifestation is increased which, arguably, IS a complication.)


I don't really want to get into a back and forth....I know where you are coming from, and I am convinced that you you're not going to give up diving the way you have been.

People should go to the source and do the reading, as opposed to listening to two guys parroting stuff that's 3 times removed from the source.

(Actually, I don't disagree with your last conclusion, except to say that, since I know some of these guys personally and talk to them on the phone, that would make it only twice removed in my case.) :doctor:

[Braunbehrens]

I never said that Helium is bad. I don't want to continue the back and forth, but feel that I need to set the record straight on this. I don't know where you get this.

I didn't take anything you said personally, I'm simply pointing out that I don't do what I do based on how it makes me sound or anything of the sort. You several times now have referred to how something makes you look or sound, how something is "arcane" etc.

I don't care about being cutting edge, I don't care about being cool, and I don't care about impressing others. I care about what works, and why.

Any other attitude towards diving is IMO dangerous. Wanting to use the latest and greatest is exactly what drives people to use electronically controlled CCR's. No thanks....and no, I'm not going to debate that one either.

[Doppler]

There are a couple of very important reasons why the use of a computer is counter-indicated for decompression diving... OPEN CIRCUIT decompression diving... and it seems important to bring them up here.

To begin with, computers encourage poor planning, and poor understanding of the shape of the algorithm. Neither is a good habit to take into the world of decompression diving.

Secondly, and perhaps more importantly, computers (and I generalise here) misshape the algorithm by padding it excessively.

Allow me to explain.

The largest market for scuba equipment is the USA.

When a software company builds anything that measures things related to health and well-being... and especially when it uses a licensed algorithm... the legal department get seriously involved. In fact, they might even read the functional specs and stand behind the applications architect when she's talking to the propeller heads.

All law suits are expensive to defend -- even stupid ones, and the legal system in the USA seems to encourage stupid law suits.

OK, so we have a lawyer telling the programming department how to interpret the algorithm... Legal has already insisted that the packaging has a huge warning against using the computer for decompression diving, but that's not enough. Legal is now asking that when the computer does get into decompression mode, it keeps people in the water longer than necessary. How much longer? Well, how long would you like?

If the lawyer is in court and has to defend the company, he can get umpteen "expert" witnesses to explain decompression theory, but the jury will not understand it. All they will take away from the cross examination is that "Decompression means staying in the water." And the corollary is "Staying longer is safer!"

I know it's dumb and makes no allowances for anything remotely related to common sense. But that's the way it is.

Computer manufacturers have to pad the algorithm to please the legal department and believe me, it's important to keep the legal department happy. Board meetings are hell when there are a bunch of pissy lawyers in attendance.

So if you want to learn to dive, forget the computer. It's like training wheels.


And just in case anyone wonders, I'm not a lawyer. But do I run a software company, and for the record, have more than 500 logged trimix dives... one of them testing a trimix computer, which incidently got bent... I did not.

Doppler

P.S. I know nothing about rebreathers. So, if you're a CC or SCC user and all of the above sounds like nonsense... please let me know. Constant PO2s make for some radical profiles... but that's another thread isn't it?

Later

[padiscubapro]

Doppler once bubbled...
There are a couple of very important reasons why the use of a computer is counter-indicated for decompression diving... OPEN CIRCUIT decompression diving... and it seems important to bring them up here.

To begin with, computers encourage poor planning, and poor understanding of the shape of the algorithm. Neither is a good habit to take into the world of decompression diving.
Later

I brought CCRs into the debate because B. stated constant PO2 was bad.. The profiles I have done on the Explorer in RGBM mode delievered some nice deco curves on both OC and CC.. and to point out even these "extreme" profiles are still below NOAA limits, I can drop the PO2 to 1.2 or 1.1 and extend my dive bottom time and keep deco in the same ball park, now the OC dive has the higher exposure.

Planning on a CCR is just as important (if not more)especially doing the dive I listed above.. I know very few OC divers who would attempt that dive especially in OW conditions. I MUST know all my bailout requirements.. I can't assume the RB will get me to the surface.. I must go into the dive ASSUMING it will faill.. Its unlikely but if its not planned for I'm probably dead.

Staying in the water is not necassarily safer.. a few extra minutes doesn't change the statistical probablilty of an accident. Any perceived safty gained ny staying longer is getting ofsset by the probability of other issues.

The profiles I listed are for RGBM profiles, haldane models especially GF dives Are MUCH longer.. The differance bewteen CC and OC get greater.


also the more tanks with different mixes you are forced to carry the greater liklihood some abnormal event may occur..

CCRs have greater training and experience requirements but every serious diver that I have ever met and gave CCRs a real chance has switched, but CCRs aren't for everyone they require the attentive diver, someone who only checks their guages once every several minutes because they know their consumption rates would probably kill themselves..

Just because you have something to breathe doesn't mean its a breathable gas!

My favorite use of a CCR is not the deep profiles but the ones that let me get long multilevel dives starting at maybe 130-150 for an hour, comming up to 100 for another 30 then cruising a reef for another 90 minutes, and having no deco reqired since it was all done at 100 and 50.... because of the rising PO2
on OC this type of dive is unpractical in Ow since it would require at least 700cu ft of gas plus deco gas , in a cave you could at least have divers staging tanks of various mixes..

[Doppler]

padiscubapro once bubbled...


I brought CCRs into the debate because B. stated constant PO2 was bad.. The profiles I have done on the Explorer in RGBM mode delievered some nice deco curves on both OC and CC.. and to point out even these "extreme" profiles are still below NOAA limits, I can drop the PO2 to 1.2 or 1.1 and extend my dive bottom time and keep deco in the same ball park, now the OC dive has the higher exposure.

big snip
..

One of the real advantages of a constant PO2 in CC is control of the CNS and since there's no PO2 spike, not real need to toggle upper / lower doses... at least that's the way I read it... is that the way you run it?

What sort of CNS loading do you habitually run on the long "reef" dives? Sounds like you'd be in the 40s or 50s.

And I know one day you CC guys will win me over, but I have less than a dozen CC dives and one of them was my most unfavorite experience underwater. Felt like I was driving a bus... anyway, I stay with my tanks for the time being thanks!

[padiscubapro]

Doppler once bubbled...


One of the real advantages of a constant PO2 in CC is control of the CNS and since there's no PO2 spike, not real need to toggle upper / lower doses... at least that's the way I read it... is that the way you run it?

What sort of CNS loading do you habitually run on the long "reef" dives? Sounds like you'd be in the 40s or 50s.

It depends what I am planning... Sometimes I'll do a long single dive in the day.. if I do that a 3hr run time for a single dive i'll run 1.3 for a 100% exposure..

I am not advocating exceeding noaa limits but I have done 5 and 6 hours in a single day with a po2 of 1.3 (usually I'll back it down to a 1.0-1.2 for the shallower stuff) .. In these case I always made sure I had at least 90min surface intervals between dives and dives get shorter as the day goes on...


On a typical 90 minute dive regardless of depth I'm still only going to hit a cns of 50% and my reatio of reall bottom time to dive time is much better than the OC diver.. I think the lack of PO2 spikes allows the body to hanle the elevated PO2 better...

The only negative effect I have ever had from rebreather use was hyperbaric myopia (prolonged elevated oxygen levels alter your vision) it generally returns to normal after a few days.. I experienced this after 3 plus weeks of 4 - 6 hours a days on my rebreather.. (and I probably could have avoided this if I didn;t run the RB as an oxygen RB at my 20ft stop on the deeper stuff)

AN occasional CCR dive probably screwes you up more than anything.. your buoyancy gets all screwed up.. The first thing I tell my CCR students (or potential students) if you really want to dive a CCR and become proficient you MUST give up OC totally for the time being.. If you keep switching back and forth you never begin to thing as a RB diver... its a totally different mind and skill set.

I can vaguely remember my progression... The first thing I remember was... Why the hell did I do this.. I just wasted my money!.. but I gave it a chance.. after about 30 hours on the unit I though this isn't that bad... by 100 hours... I'm never going back..