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I am probably talking to a wall here but I'll bite. ------------------------------------------------------------------- Learn About Trimix at http://www.cisatlantic.com/trimix/ > From: KRussellTX@ao*.co* > Date: Sun, 27 Aug 2000 03:14:35 EDT > To: cobber@ci*.co*, techdiver@aquanaut.com > Subject: Re: 80/20 deco >=20 > Jim, >=20 > You idiot. What I'm trying to tell you is that either decoplanner is wron= g or > the items in the bakers dozen are each basically irrelevant or incorrect. >=20 > Tell me what #1 and #2 say about why I should not use EAN80. Everybody wants to know where a bad idea got started. What puzzles me is ho= w they get perpetuated year after year even in the face of overwhelming logic= .. It would require some real muscle-brained chowderheads in leadership position supported by hordes of like-minded individuals following zombie-like because they are incapable of thinking for themselves. > Tell me from #3 why on earth I need to dive your standardized set of gass= es. > I'm not doing ridiculous 3 mile penetrations at a 300 ft. depth. Also te= ll > me from #3 exactly what are the "benefits of pure O2," as they are never > given. Kurt, for those of us who actually dive this is a good example of why I am willing to spend the extra 5 mins. for the sake of standardization. On a dive boat (Kurt, that's a floating thingy with a motor on it that takes divers out diving) you have 6-15 techdivers with deco bottles and doubles all over the place. It is a huge advantage if every deco bottle has either 50 or 100 in it, that way should there be a problem on the surface or at deco you can use each others gas. I know that armchair divers like you can'= t comprehend logistics like this, but I guess how can you if you have never been there or done that. > Tell me from #4 how for any dive that I (or 99.9% of all tech divers for = that > matter) might make, I << will not want to accelerate your ppo2 at lower > depths while still being faced with a long decompression at shallower dep= ths, > and making bizarre mixes to do this is a dangerous mistake...>> This is > just not true when the total deco is less than an hour or two and the dec= o > with the EAN80 is actually less in total time than with the 100% O2. Of > course the 30 ft. stop is going to be shorter and the 20 ft. and 10 ft. s= tops > somewhat longer, but not enough to worry about. When was the last time y= ou > carried enough gas and did a dive requiring a deco of more than two hours= ? > No hogwash about scooters, habitats and bunches of support divers, just y= ou > and a buddy or two swimming in the ocean. Yes, Kurt, us divers are known to make more than one dive a day. Out on the boat we may do 3-4 back-to-back tech dives. Once again your armchair knowledge fails you. > Tell me from #5 why the magic number for PO2 of 1.6 is so fantastically > better than 1.53 (I guess the DIR guys never learned about rounding numbe= rs > to the significant digit). Sure it's a little better, but lets not go > overboard. The PN2 is still way down so the deco will be effective. I'v= e > heard that the idiot WKPP guys use 100% O2 at 30 ft. in a habitat. Tell = me > now why 1.6 is still the magic number rather than 1.91, or is it the secr= et > DIR method to deco on a PO2 of 1.91 and not tell anyone? In my opinion, = the > whole argument of 1.6 verses 1.53 is just a bunch of hoopla. As somebody else pointed out it's the removal of NITROGEN from the picture is the goal. Kurt, it's NITROGEN that gets you bent. Where you asleep durin= g that phase of your obviously deficient education? > Tell me what #6 says about why I should not use EAN80. Once again, explaining the roots of a bad method helps to illuminate the path to redemption. > Tell me from #7 why I give a hoot if some rec. scuba shop has a heartache > about making nitrox by the partial pressure blending method. The vast > majority do it this way so this also is a non-issue. And what is wrong w= ith > stages on either side if you're not using a scooter? For me, swimming wi= th > two 80's on one side and nothing on the other is not particularly conveni= ent. This armchair diving experience of yours is really showing, Kurt. I don't know how many times I have seen real divers try both methods and switch ove= r to having both bottles on the left. Forget all the logical reason why (you have the blinders on, so why bother) just try it and you will like it. > Tell me from #8 how either this is just plain wrong for the example I gav= e, > or how decoplanner is wrong. Really Kurt you need to read something other than comic books once in a while. Or perhaps you don't know what an algorithm is. An algorithm is a procedure for solving mathematics problems. While good baselines, deco has too many variables to come up with an all encompassing formula. As I type I can see my words entering your eyes and flowing out your ears. Why do I bother? > Tell me from #9 how, when the K bottles of O2 only come with around 2250 = psi > so I'm real lucky to get 2100 psi in a deco tank, that I'm not going bene= fit > from getting 2800 psi of EAN80 in that same tank. In your dreams if you'= ve > ever done any diving. Remember that if you use 100% O2, then you need to > plan your 30 ft. stop from your first deco gas. And if the total deco is > shorter using EAN80 (see #8), then you need less deco gas total and you h= ave > significantly more. Tell me again how this is bad. Sigh.... Kurt, answer me this question: is the goal of deco diving to have the correct amount of deco gas available for your dive or to pump as much gas as possible into your tanks? How do you benefit by dragging around gas you are not going to use? Once again your total lack of real world experience is yawning open like the goddamn Grand Canyon. > Tell me from #10 how << The 20-30% longer 30 foot time on the lower ppo2 = is > not only overcome on the pure oxygen at the next stops ... >> is simply n= ot > true for the example I gave (or decoplanner is wrong). This statement is > simply not valid for the example I gave (see #8 again). Duuuuhhhh, um, uh Oh, I know! There's nitrogen in 80/20! The goal of deco i= s to remove nitrogen! So why breath it? > Tell me from #11 how you arrived at the conclusion that pure O2 at 20 ft.= is > that much better than EAN80 at 30 ft. or 20 ft. No smoke and mirrors, ju= st > facts or references. And tell me how in the blazes anyone with an > organization that never has diving deco medical problems, would have the > experience to pontificate about what is necessary for << living through i= t > with pain hits only... >> This is pretty funny. The whole 80/20 argument is some and mirrors. You are one pig-headed individual. Once again, there's nitrogen in 80/20! The goal of deco is to remove nitrogen! So why breath it? > Tell me what #12 says about why I should not use EAN80. Any idiot knows = to > always have O2 available when diving. I choose to use a DAN O2 kit with = only > a Jumbo "D" cylinder, and a DAN REMO surface O2 rebreather which on the > surface will stretch the small DAN cylinder out to five or six hours if > necessary. I'm certainly not going to try to use this stuff under water. Ah, you armchair divers are going to be the death of me. Us real divers jus= t take along a couple of K cylinders of O2 and attach a hooka rig for the guy= s to deco on. We take 02 with us but us the hooka when we can. Draining the 0= 2 out to remix for 80/20 for moron strokes like you is, uh, counter-productive? > Tell me what #13 says about why I should not use EAN80. Call me a stroke= if > you like, but that is not a reason to not use EAN80 for a deco gas in cer= tain > situations. OK. You Stroke. "Certain situation". Kurt, does armchair diving give you hemorrhoids? Real divers standardize on 50, 100 and perhaps add a 36 for th= e 400 footers. Other than that I can think of no dive on this planet or on th= e planet you apparently came from to use 80/20. Why? Because theres NITROGEN in 80/20 (Kurt that's the "20" part) and the goal of deco is to offgas NITROGEN. Am I making a dent in that wall-to-wall bone head of yours? > Now that we have done away with your thirteen commandments, that you foll= ow > like a lemming because you obviously don't have the ability for any > independent thought, lets look at your arguments. History is nice but > unfortunately, it doesn't replace logic. You may have been on the techdi= ver > list for some time but from what I have read, you have simply demonstrate= d on > numerous occasions in the past that you're basically incapable of logical > thought. And that when faced with a logical argument, you invariably res= ort > to calling other people dirty names and using an abundance of rather filt= hy > curse words in an attempt to overwhelm and wear down your opponent. Your > present posting is a prime example. Well, you'll find that this tactic w= ill > not work with me. Kurt, some people deserve all the abuse they get. People like you are so thick-headed and in lock-step with their agency's party line (You are a TDI asshole I will guess?) that logical discussion is hopeless. You are the proverbial pig we are trying to teach to sing. > In your first posting to me on this subject you claimed << fact is that > getting out of the water in the least amount of time should not be the > primary objective. >> I answered with << Decoplanner showing your needin= g > less deco means that everything is in the right direction. The nitrogen = is > gone quicker from your body and with no oxygen toxicity worries, so [when > talking about deco - KR] what else is there that's "the primary objective= .." >>> . As I said previously, your "modus operandi" when faced with a logica= l > argument, is to ignore the logic and attack your opponent. And you have > definitely measured up true to form in your second posting to me. Oh, my such big words! Yes, Kurt, optimizing your 02 window, standardization, keeping it simple (stupid), logistics all come before trying to save 5 fucking min.s of lousy deco. > Perhaps there may be some valid reasons for not using EAN36 and EAN80 as = the > deco gasses for the dives I do, but you certainly haven't found one yet. > Care to try again? Or do you plan on simply haranguing me with your typi= cal > barrage of dirty words. OK, Kurt, lets try again in the key of "C" ..."I'm siiiinging in the rain, siiiinging in the rain" .... are you getting annoyed yet? I know I'm wastin= g my time... > Oh and by the way, if you knew how to read at a somewhat higher level tha= n an > initial course in Phonics (although I'm sure you found the game challengi= ng), > you would have been able to determine from my previous email that my name= is > Karl, not Kurt. And to give your little mind a challenge, that's K as in > knight, A as in aisle, R as in are, and L as in solder. If that's to tou= gh > for you, then ask your remedial reading teacher for a little help. You d= o > have a remedial reading teacher, don't you? >=20 > Kurt Russell, Austin, TX So far, Kurt, I can't think of a single reason to get your name right. > In a message dated 8/26/00 7:08:36 PM, cobber@ci*.co* writes: >=20 > << So what you are telling me, Kurt, that for saving 5 lousy mins of deco= you >=20 > are going to ignore all of the issues outlined in the bakers dozen. Real >=20 > bright, Kurt. I can tell your mind is really open to all the possibilitie= s. >=20 >=20 > Listen, dimbulb, like all tables programs, Deco Planner is an algorithm. >=20 > Tables software are not some magic oracle to keep you from getting bent, >=20 > they are just guidelines and training aids to help you understand deco. Y= ou >=20 > would be a fool to use them without some understanding of how deco affect= s >=20 > your body. >=20 >=20 > And Kurt, as far as me knowing everything, I do not. But I do know enough= to >=20 > use the archives to see what *you* had to contribute to the general well >=20 > being over the course of 50,000 posts. Not surprisingly, not a FUCKING >=20 > thing. Well done, Kurt, I'm really impressed, you must be one hell of a >=20 > diver. >=20 >=20 > I'm getting sick and tired of you anti-DIR zealots. Don't you assholes >=20 > realize that nobody cares how fucked up your gear is, or what goddamn gas= ses >=20 > you use? As more of you fuckheads croak in some horrible fashion or other= , >=20 > DIR will come out on top by attrition alone. And you people are too stupi= d >=20 > to see that, aren't you. >=20 >=20 >=20 >> From: KRussellTX@ao*.co* Date: Sat, 26 Aug 2000 18:13:57 EDT To: >=20 >> cobber@ci*.co*, techdiver@aquanaut.com Subject: Re: 80/20 deco >=20 >>=20 >=20 >> OK Jim, >=20 >>=20 >=20 >> Yes this again. Since you seem to know everything, I'd like you to tell= me >=20 >> that if getting out of the water in the least amount of time (safely, >=20 >> according to decoplanner) isn't the primary objective, then just what in= the >=20 >> hell is. >=20 >>=20 >=20 >> Decoplanner showing your needing less deco means that everything is in t= he >=20 >> right direction. The nitrogen is gone quicker from your body and with n= o >=20 >> oxygen toxicity worries, so what else is there that's "the primary > objective." >=20 >>=20 >=20 >> Also, since the EAN36 and 80/20 actually gives you less deco then your E= AN50 >=20 >> and 100% oxygen, you can throw just about every single one of your Baker= 's >=20 >> dozen commandments in the trash can. They just don't hold up. Unless o= f >=20 >> course, you mean to say that decoplanner is giving the wrong answer. >=20 >>=20 >=20 >> So take your patronizing attitude and go stuff it where the sun don't sh= ine. >=20 >> When you have something intelligent to say then maybe I'll listen. Unti= ll >=20 >> then, which will be a very long time I'm sure, just try to go play bully > with >=20 >> those that mistakenly believe that you actually know something about div= ing. >=20 >>=20 >=20 >> Karl >=20 >>=20 >=20 >> In a message dated 8/26/00 6:35:03 AM, cobber@ci*.co* writes: >=20 >>=20 >=20 >> << Oh, no, not this again... >> >=20 >>=20 >=20 >> The fact is that getting out of the water in the least amount of time sh= ould >=20 >> not be the primary objective. >=20 >>=20 >=20 >> Do us all a favor go to Kevin Connell's archives and do a search for 80/= 20 > or >=20 >> Bakers Dozen and save us a lot of bandwidth. >=20 >>=20 >=20 >> http://www.nwls.com/list-archive/ >=20 >>=20 >=20 >> If you have any additional questions, come on back and ask. >=20 >>=20 >=20 >> Jim >=20 >>=20 >=20 >> ------------------------------------------------------------------- Lear= n >=20 >> About Trimix at http://www.cisatlantic.com/trimix/ >=20 >>=20 >=20 >>> From: <KRussellTX@ao*.co*> Date: Sat, 26 Aug 2000 02:30:37 EDT To: >=20 >>> techdiver@aquanaut.com Subject: 80/20 deco >=20 >>>=20 >=20 >>> I have been reading in this group how 80/20 is not the gas to use for > deco. I >=20 >>> have also been reading that Decoplanner is great and EAN50 @ 70 ft. and > 100 % >=20 >>> oxygen at 20 ft. is the DIR way to go. In truth I haven't got the > slightest >=20 >>> idea what the "oxygen window" means unless it simply refers to using th= e >=20 >>> closest PO2 that is below 1.6 that you can get to. >=20 >>>=20 >=20 >>> Now the question I have to ask is that if 80/20 is only used by strokes= , > why >=20 >>> is it that on a dive to 200 ft. on 18/35 for 30 minutes, doing a deco u= sing >=20 >>> EAN 36 @ 110 ft. and EAN 80 @ 30 ft. actually results in a shorter deco > than >=20 >>> EAN50 @ 70 ft. and 100% oxygen @ 20 ft.? >=20 >>>=20 >=20 >>> Any explanations why the stroke mix seems to get you out of the water > sooner? >=20 >>>=20 >=20 >>> K. Russell >=20 >>>=20 >=20 >> In a message dated 8/26/00 1:16:10 PM, Michael.Waldbrenner@wa*.d= e >=20 >> writes: >=20 >>=20 >=20 >> << >terms of the O2 clock. I was not able to find the bakers dozen for > oxygen. >=20 >>=20 >=20 >> Here you go ! 1997 ! >=20 >>=20 >=20 >> Just for the record here on Quest. Tom Mount is writing in the rebreathe= r >=20 >> forum that IANTD is using EAN80 for OW-Deco. >=20 >>=20 >=20 >> When doing some of my courses at Billy Deans in Key West a few years ago= , we >=20 >> were mostly using surface supplied oxygen for the deco-dives. >=20 >>=20 >=20 >> And to the ever-occuring buoyancy thing.... Deans was very strict on the= se >=20 >> things like buoyancy, beeing on time, beeing fit, etc... I remember he > kicked >=20 >> one guy out, because he did not arrive on time at the dock to leave for = the >=20 >> dive in the morning. >=20 >>=20 >=20 >> Billy told him: "You are not in time at the boat, so you will not be on = time >=20 >> at the stops". >=20 >>=20 >=20 >> Deans was IANTD #2 and he was using O2 ! I don=B4t want to speak for IANT= D, > but >=20 >> i think Billy Deans was right ! >=20 >>=20 >=20 >> Michael >=20 >>> ---------------------------------------------------------------------- >=20 >>> A (BAKER'S) DOZEN REASONS WHY WE DO NOT USE 80/20 (By George) >=20 >>>=20 >=20 >>> 1) This gas was introduced in an effort to overcome the inability of >=20 >>> unqualified student "tech" divers to control their buoyancy in open >=20 >>> water, and is as such is yet one more concession to doing things in a >=20 >>> convoluted fashion to offset a self- inflicted set of problems brought >=20 >>> on by the "doing it wrong" thinking that pervades diving today. >=20 >>>=20 >=20 >>> 2) A heavy sea is not a problem for a deco stop if it is not posing a >=20 >>> lung-loading problem. Look at your depth guage in a heavy sea and "see" >=20 >>> for yourself what the changes are - insignificant, and if they are not, >=20 >>> you should either not have been diving or incurring a decompression >=20 >>> liability of this magnitude in the first place. In the event of a chang= e >=20 >>> in conditions during the dive, see below where the 80/20 becomes a >=20 >>> liability rather than an assett. >=20 >>>=20 >=20 >>> 3) In the interest of using a standardized set of gases for which you >=20 >>> can permanently mark your bottles , it is a poor concession to inabilit= y >=20 >>> to sacrifice the benfits of pure O2 to accomodate a real or percived >=20 >>> lack of skill - learn to dive before taking up techdiving. >=20 >>>=20 >=20 >>> 4) In this same interest you will find that when you graduate to real >=20 >>> diving, as in caves, you will not want to accellerate your ppo2 at >=20 >>> lower depths while still being faced with a long decompression at >=20 >>> shallower depths, and making bizarre mixes to do this is a dangerous >=20 >>> mistake (just like the fantasy of holding an accellerated ppo2 on a >=20 >>> rebreather throughout a deco). I am anticipating the thinking that the >=20 >>> 80/20 crowd would then go to an additional oxygen in cave without >=20 >>> accounting for total exposure, and subject themselves to the risk of to= x >=20 >>> in the final deco steps. Tox you do not get out of - bends you do. >=20 >>>=20 >=20 >>> 5) The 80/20 mix is in fact totally useless and contraindicated as a >=20 >>> deco gas. At thirty feet it is only a 1.52 ppo2 ( the real 1.6 ppo2 >=20 >>> gas would be 84/16) and as such does not either provide the right >=20 >>> oxygen window, nor does it does it work as well as pure oxygen without >=20 >>> an inert gas at any depth. The gas mixing in your lungs has already >=20 >>> lowerd the effective ppo2 enough to prevent spiking at 20 feet anyway >=20 >>> with the use of pure oxygen - in other words, we aer dealing with a >=20 >>> simplisitc misunderstanding here, or "old wives tale" that is typical i= n >=20 >>> diving. >=20 >>>=20 >=20 >>> 6) If 100% oxygen is a percieved buoyancy control risk at 20 feet, then >=20 >>> why is the same ppo2 ( intended) not a risk at 30 feet? This shows th= e >=20 >>> total lack of reasonable logic involved in the decision to use this gas= , >=20 >>> as well as a lack of understanding of the whole picture ( see the rest >=20 >>> of this discussion). >=20 >>>=20 >=20 >>> 7) Along those lines, all we hear is howling about "oxygen cleaning" >=20 >>> above 40% mixtures, and dive shop proprietors on here complaining abou= t >=20 >>> scuba tanks with oxygen in them being filled in their shops. With a >=20 >>> pure oxygen system, the tank only ever gets filled with oxygen from >=20 >>> oxygen tanks, not from every dive shop compressor it sees. Again , this >=20 >>> shows the total inconsistency of agency thinking, and reveals that the >=20 >>> true reason for this gas is to pretend to lower liability for teachin= g >=20 >>> incompetents to dive, which is bull, and to attempt to accrue some >=20 >>> inventive accomplishemts to the dive agency pundits who themseleves >=20 >>> prove that they do no real diving by making this recommendation >=20 >>> in the first place. This is like the colored regs, the stages on eithe= r >=20 >>> side, the quick-release buckle, and the poodle jacket: nonsense of the >=20 >>> most obvious nature developped through one-dimesional thinking by those >=20 >>> whose universe of understanding is not only severly limited, but blinde= d >=20 >>> by the hubris of not being the "inventor" of the techniques that work. >=20 >>>=20 >=20 >>> 8) Any perceived decompression benefit of using a higher ppo2 at 30 >=20 >>> feet with 80/20 is then given back by the lowered ppo2 at 20 feet, no= t >=20 >>> to mention the fact that the presence of the inert gas in the breathin= g >=20 >>> mixture defeats the purpose of using oxygen in the first place ( see >=20 >>> the Physiology and Medicine of Diving) . The ppo2 of 80/20 at 20 fee= t >=20 >>> is 1.28, not much of an oxygen window, and at 10 feet it is 1.04 - >=20 >>> useless for deco. To make matters worse, you can not get out from your >=20 >>> 30 foot stop in an emergency ( not doing the other stops) on the 80/2= 0 >=20 >>> mix without really risking a type 2 hit. >=20 >>>=20 >=20 >>> 9) This is a dangerous method to achieve a greater total volume of gas >=20 >>> for the bad breathers (another obvious reason the gas is in vogue), who >=20 >>> should not be incurring these decos, and even that benefit of having >=20 >>> more gas is lost since it is breathed at 30 feet, and then has to last >=20 >>> for the other stops. The fact is that gas is effecively saved by using >=20 >>> the lower deco gas up to this point, relying on the pressure gradient >=20 >>> to both achieve the deco and provide a break from high the previous >=20 >>> gas's higher PPO2 prior to going to pure oxygen where the spike could >=20 >>> be a problem on an extreme exposure without an adequate low ppo2 break = ( >=20 >>> again this shows that the 80% user is a neopyte diver with no real >=20 >>> experience or understanding of the true risks of these dives) . >=20 >>>=20 >=20 >>> 10) The 20-30% longer 30 foot time on the lower ppo2 is not only >=20 >>> overcome on the pure oxygen at the next stops, the breaks do not come >=20 >>> into play until the initial good dose of pure oxygen has been absorbed, >=20 >>> since you are not spiking from a high pervious dose without a break >=20 >>> that is effectively achieved on the previous gas. These things need to >=20 >>> be understood and taught by the agencies, not some superficial >=20 >>> convolution that is designed to obfuscate the problem rather than >=20 >>> openly acknowledge and deal with it in a responsible fashion. >=20 >>>=20 >=20 >>> 11) In an emergency situation, getting onto the pure O2 for 20 minutes >=20 >>> or so (for long dives something approximating the bottom time or a any >=20 >>> decent interval) would give you a real good shot at getting out of >=20 >>> the water having missed the rest of your deco and living through it >=20 >>> with pain hits only. You have to think these things all the way though, >=20 >>> not go for the transparent superficial thinking of those who merely are >=20 >>> trying to "make their mark" with some "great" idea they can call their >=20 >>> own. The acid test is , as always, is the caliber of the divers who >=20 >>> adopt these practices. >=20 >>>=20 >=20 >>> 12) If there is some problem with your deco or you otherwise develop >=20 >>> symptoms and need oxygen either on the surface or back in the water, it >=20 >>> is silly to have not had it there all along. 80/20 is a joke for that >=20 >>> purpose, unless you have asthma, in which case any accellerated oxygen >=20 >>> mix would be a nightmare. This is again part of the "thinking it all th= e >=20 >>> way through" phiosophy which is obviously mising from the 80/20 >=20 >>> argument. >=20 >>>=20 >=20 >>> 13) Only a card-carrying stroke would do somethng like this, and >=20 >>> showing up with 80/20 is no different than wearing a sign on your back >=20 >>> saying "I am a stroke, and have the papers to prove it". It announces t= o >=20 >>> all the world that you have no clue, kind of like wearing clip-on >=20 >>> suspenders or having dog dirt on your shoes. >>>=20 >=20 >>> George Irvine >=20 >>> Director, WKPP >=20 >>> "Do It Right" (or don't do it at all) >=20 >>>=20 >=20 >> ------------------------------------------------------------------------= ---- >=20 >>> Bill Mee's post: >=20 >>>=20 >=20 >>> George, >=20 >>>=20 >=20 >>> Thank you for exhaustively laying the reasons why we or anyone else >=20 >>> should not use 80/20. The only thing missing from this discussion is >=20 >>> the Q.E.D. at the end. >=20 >>>=20 >=20 >>> Reason #8, reiterated here for discussion purposes is perhaps the >=20 >>> soundest reason, among many very cogent ones, as to why this practice >=20 >>> should be avoided: >=20 >>>=20 >=20 >>> " Any perceived decompression benefit of using a higher ppo2 at 30 feet >=20 >>> with 80/20 is then given back by the lowered ppo2 at 20 feet, not to >=20 >>> mention the fact that the presence of the inert gas in the breathing >=20 >>> mixture defeats the purpose of using oxygen in the first place ( see >=20 >>> "The Physiology and Medicine of Diving") . The ppo2 of 80/20 at 20 >=20 >>> feet is 1.28, not much of an oxygen window, and at 10 feet it is 1.04 >=20 >>> useless for deco. To make matters worse, you can not get out from your >=20 >>> 30 foot stop in an emergency ( not doing the other stops) on the 80/2= 0 >=20 >>> mix without really risking a type 2 hit. " >=20 >>>=20 >=20 >>> The rush to embrace this practice, recommended by technical diving >=20 >>> diving opinion leaders, was widespread and in retrospect, irrational an= d >=20 >>> poorly thought out, like so many of the "trial balloons" in this field >=20 >>> of endeavor. It seemed to many, at first glance, to be a simple means o= f >=20 >>> increasing one's supply of deco gas while eliminating its bothersome >=20 >>> volume and mass. In fact, the perceived benefits tranform into >=20 >>> liabilities when subjected to a thoughtful analysis. When you view >=20 >>> decompression as a two pronged challenge: to progrssively widen the >=20 >>> oxygen window and increase the diffusion gradient to maximize passive >=20 >>> transport of dissolved inert gas, it becomes clear that the 80/20 >=20 >>> solution falls short on both requirements at a critical point in the >=20 >>> decompression profile. >=20 >>>=20 >=20 >>> Section 11 emphasizes a very compelling argument for those who are >=20 >>> concerned with managing dive related crises. When diving in the open >=20 >>> ocean divers and boat operators should always be prepared to "scram" th= e >=20 >>> deco at any time. This could be for any number of reasons, not the >=20 >>> least of which might be a sudden change in the sea conditions or >=20 >>> unscheduled events such as dive accidents or impending ship collisions. >=20 >>> Just follow the Whitefish Point thread for an excellent example of why = a >=20 >>> deco may require being aborted (or never started in the first place). >=20 >>>=20 >=20 >>> Most unfortunately the "80/20 problem" bears a strikingly resemblance t= o >=20 >>> several other ad hoc technical contrivances mentioned in this same >=20 >>> article (section 7) i.e. dual bcs, colored regulators, bilateral stage >=20 >>> bottle postioning, poodle jacketed second stages and harness quick >=20 >>> releases. All of these ideas, while seemingly reasonable, become >=20 >>> tainted when subjected to thoughtful review. >=20 >>>=20 >=20 >>> Good show Director Irvine. >=20 >>>=20 >=20 >>> Bill Mee >> >=20 >=20 -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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