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Hi Tom, Thank you for the well thought out and reasonable post. I appreciate your taking the time to summarize the subject in an attempt to end the thread. I too was getting a little too caught up in answering the various replys. I agree that enough has been said on the subject and it's time to move on to other things. If anyone would like to discuss this further with me, please contact me off the list. But I'm heading off to Fiji this evening for some simple fun diving, so it'll be a week or two before I can respond. Tom, this is not really in direct in answer to your message, but I should like to use this opportunity to send my heartfelt thanks and congratulations to the members of this list. Many times it has been said of this list (by those not really involved) that either you completely agree with DIR or you will be flamed unmercifully for opening your mouth (or keyboard). Well, when I started this thread I knew I was questioning some of the techniques of DIR diving. Yet in over 30 responses I received from the list (both on the list and private) dealing with the subject, many of which expressed opinions that disagreed with mine and clearly thought I was not only wrong but probably a little bit weird for even suggesting the ideas that I did, there was not one single "Flame" or derogatory personal comment. The discussion always centered on the issues at hand and never degenerated into a name calling contest. And I want to thank you guys for this and hold this out as an example to those who say that you can't participate on this list unless you are 100% DIR. You sure can. We're all learning and I appreciate the opportunity to do so from this list. Tom, thanks again for providing the means for ending this thread in a conciliatory and civil manner. You take care and safe diving, Scott In a message dated 6/14/00 4:38:01 PM, tmcdonal@sw*.ne* writes: << Okay, this thought process can go around and around indefinitely, when talking about the "one day" scenarios. I too like the idea of a dive computer reliably getting me out of the water faster based on the actual dive over a PC based program where the dive was planned. This doesn't contradict "Plan your dive and dive your plan". On a PC, I can plan on it taking me 3 minutes to reach depth, but when you get out to the site, it actually takes 4 minutes, or 2, or whatever. Likewise when ascending, you leave the bottom 2 minutes earlier or later, but you decompress with basically the same profile you cut. The deco can be easily adjusted for more dramatic cases once you've experimented with the plan, seeing how the decompression shifts. Now if I understand correctly, the idea with your (our) dream computer, is that it will take into account every variance in your actual dive, and adjust your deco appropriately and thereby getting you out of the water faster. Just as the recreational dive computers do within NDL as opposed to NDL tables. Agreed? And can we also agree that this computer doesn't exist today? And that's the rub. If this item doesn't exist, that we can dream all we want, but it's a moot argument. Immersed magazine recently ran an article about a pill that would assist or eliminate decompression with a bacteria that "eats" nitrogen, but this doesn't exist yet. Some company has created what they call a "swimable" JIM suit. So let's extend the "technology isn't here yet" argument to these as well. Wouldn't it be nice to have an affordable 1 atm suit that allowed great mobility for exploration, but required no decompression? Or how about the development of the above pills, so a decompression emergency could be avoided this easily? Although it may not come across this way, I'm truly not being sarcastic here. It's just too easy to dream about what would be great "some day". In reading the archives, you'll find examples of GI moving from one type of regulator to another, or even valves for his tanks. These are examples that come off the top of my head, but I'm sure these lots more throughout the evolution of his rig. As improvements are created / discovered, they can be incorporated. This isn't a static evolution. There also needs to take into account what I'll call the "lawyer factor". Dive computers are purposely designed to be more conservative that necessary, because they tend to encourage diving by what the display says, rather than a proper plan. The Cochrans you mention are some of the worst offenders of this. In looking into a trip to Bikini, the local divemaster gives a list of non-acceptable computers ( http://www.rreinc.com/fabioletter.html ). There's a dead link in this description that used to describe how 100% of the Cochran computers that customers brought have failed, giving outrageous deco times like 99 hours or displaying no information. However, when the divemaster brought this to Cochran's attention, they responded in a pretty weak (IMO) way stating that the computers were working correctly, and it was the customer's fault for using it incorrectly: http://www.rreinc.com/fabioletter.html . I read and ignored the first couple of your responses, but you won't let this die. I absolutely love my Uwatec Air-X Nitrox for *recreational* diving. In some of the black water around here, I wear a compass on one wrist and the computer right next to it. It's great having depth, time, pressure, and direction in one easy to read area. At one time I owned an Oceanic DataTrans, and liked it until I started taking some technical classes. I took it on some deeper dives (160ft) and one time it kept me in the water 20 minutes longer than Navy tables! Another, it crapped out completely, and on three times the air integration didn't work (ran a SPG off the other post thank god). If I could have my dream device, I would go with a computer that uses the actual Deco Planner Abyss or software (they tried to incorporate RGBM into the Explorer, but couldn't get it functional, and started production omitting RGBM), was backlit (no matter how bad of vis, on that Oceanic, I could push a button, stick it against my mask and read the [incorrect] numbers it was giving me), and I could switch to gauge mode at any time without a lockout period. As long as I'm dreaming, might as well throw in a built in compass and air integrated (I know I'm in the minority here, but it's nice when it's working). Maybe a sonar receiver too? Okay, now I am being sarcastic. Since this doesn't exist, why argue the merits of it? As you may guess from the above I'm not a DIR diver, and I'm not going to get into where I differ, but I try to stick with the tenant of "if it's not necessary, don't bring it." A perfect example is with me liking the air integration, but not using it on decompression dives. If I keep one SPG off my left post, I really don't think the transmitter off my right post makes any difference or is a liability. However, I do have to carry around the computer that receives the signal in addition to a bottom timer. When I bend the hell out of the computer by following a predetermined plan with gas changeovers, then the computer has become a liability and the air integration doesn't offset that. Give me Uwatec's bottom timer with air integration built in, and I'd use it. Finally, I agree with you that people shouldn't blindly accept as good or bad because an individual says so, as that's where true learning and understanding come in. Similarly, you can study deco theory all you want. However, nothing will do more for your understanding than planning many dives in advance and playing with how more minutes here and there, differences in depth, and different gases affect deco. Then go out and execute those dives. While you and I want this dream dive computer, I'd want people to have it with having a good understanding of deco theory. If / when the technology is available to create this device, the *need* to learn that information will be gone. If this working "dream" product ever came out, there's those who would never want switch from cutting tables for each dive. When BC inflators first came out, everyone thought it was a waste of gas (why put air into the BC when you can exhale into it?). I'd recommend anyone to try this at least one on a dive to see how any "savings" in exhaling is offset by the near hyperventilation that's required to fill a BC. Improvements in diving technology have brought us extremely far in a few decades and there's going to be some amazing things headed our way in the decades to come. While it's fun to speculate on what that future holds, can we stop beating this subject to death for now? Current dive computers can't take me where I want to go and get me out of deco faster than planning on a PC and following that profile. Someday, maybe. Until then, let it go. -Tom ScottBonis@ao*.co* wrote: > Hi Simon, > > Thanks for the response, I appreciate the thoughts. > > << So now you need two Deco computers and a host of remote sensors AND a PC + > Deco software to cut your backup tables which you then keep in your pocket. > Sounds like a very expensive disaster waiting to happen. >> > > I'm afraid that you're absolutely right in that what I've been talking about > would certainly require two hoseless computers with sensors. And a PC and > deco software would certainly be nice for planning, gas usage and generalized > conservative backup tables. So I guess your statement about being expensive > is clearly valid. However the assertion about being a "disaster waiting to > happen" is not clear to me. Could you possibly be a little more specific? > > << Do you honestly believe that after relying on the Deco computers, you will > be able to > figure out a deco schedule in your head if/when the s**t hits the fan ? >> > > I can honestly answer this question with a resounding "Of course." I believe > the best analogy I have here is for recreational no-deco diving. I like to > believe that I have a pretty solid familiarity with the no-deco tables, yet > for the last five or seven years I don't believe I have made one single dive > without a dive computer. The quest for knowledge is something quite > personal, and is not necessarily driven by simple expediency. > > << The DIR guys have been through all this before and distilled it into a > system that actually let > you relax and have fun doing deep, long dives. Why dont you try it ? > > Simon Murray > > South Africa >> > > I respect (and am really impressed) by the accomplishments of George, JJ and > the rest of the team. They have developed a system for the type of diving > they do and it clearly works. But that is not to say that as time and > technology progresses, we are to ignore all of the developments that are > forthcoming. > > I studied deep diving a number of years ago and am now teaching trimix and > cave. All of my training and experience was with Uwatec depth gauges / > bottom timers and (before I had a PC and deco software) the waterproof IANTD > trimix multiple deco tables. Now I can cut deco and backup tables more > specific to each dive and so get out of the water sooner. My deeper dives > this winter were below 400 ft. So I really believe that I have tried that > system. And I am still interested in exploring alternative techniques for > making deep diving safer and easier. And I believe that in the future, as > the construction of and algorithms contained in wrist computers gain maturity > e.g. incorporate deep stops, oxygen breaks, better reliability, etc., wrist > computers well may become useful for deep diving. > > Once again, thanks a lot for the comments. There's no substitute for talking > to those that have "walked the walk," so to speak. > > Take care and safe diving, Scott > > In a message dated 6/12/00 11:03:37 PM, simonm@ho*.co*.za* writes: > << > These are good questions to talk about. In an earlier post I suggested that > > it might be wise to mount the two air integrated computers on different posts > > so I imagine if there were a failure in the primary gas supply such that one > > side needed to be shut down and the isolator closed, I would simply use the > > computer that was on the good post (the one I'd be breathing) to finish the > > dive. > > So now you need two Deco computers and a host of remote sensors AND a PC + > Deco software to cut your backup tables which you then > keep in your pocket. Sounds like a very expensive disaster waiting to happen. > > Do you honestly believe that after relying on the Deco computers, you will be > able to figure out a deco schedule in your head if/when the s**t hits the fan ? > > The DIR guys have been through all this before and distilled it into a system that > actually let you relax and have fun doing deep, long dives. Why dont you try it ? > > Simon Murray > > South Africa > > ----- Original Message ----- > > From: <ScottBonis@ao*.co*> > To: <artg@ec*.ne*>; <donburke56@ya*.co*>; <techdiver@aquanaut.com> > Sent: Monday, June 12, 2000 5:11 PM > Subject: Re: Oxygen Toxicity - using 100% in open water > > > In a message dated 6/12/00 5:06:42 AM, artg@ec*.ne* writes: > > > << On Sun, 11 Jun 2000 ScottBonis@ao*.co* wrote: > > > > "How does the computer know when to switch to the deco. gasses?" you ask. > > > Good question. Magic!!! No not really, the computer is an air integrated > > > unit connected to the back tanks. It keeps track of my breathing rate during > > > the dive. And when that breathing rate goes to zero, it knows that I am no > > > longer breathing off of the back tanks so it switches to the first deco. gas > > > (the EAN 50 in this example). > > > Great. What if your primary gas supply fails, and you're in a gas sharing > > situation? Or you're diving doubles, and you have to shut down the > > isolator and you're breathing off the post the computer is not on? Now the > > computer thinks its time to switch gasses. Ooops. >> > > > Hi Art, > > > These are good questions to talk about. In an earlier post I suggested that > > it might be wise to mount the two air integrated computers on different posts > > so I imagine if there were a failure in the primary gas supply such that one > > side needed to be shut down and the isolator closed, I would simply use the > > computer that was on the good post (the one I'd be breathing) to finish the > > dive. If there were a total failure of the primary gas supply (requiring at > > least two independent failures) such that buddy gas sharing was required (I > > shudder to think of this happening on a deep dive), then as you indicated > > both computers would switch to deco gas. But if either of these primary gas > > system failures were to occur, then the dive would be called immediately and > > I (or I and my buddy together) would ascend immediately, switch to the deco > > gas and finish the dive. The only computer error would be the computer > > thinking I was on deco gas for the few minutes ascending while buddy > > breathing. And the backup waterproof tables, using the computers as depth > > gauges / bottom timers, could always be used to figure a new deco scheduleif > > needed. > > > << IMO, any dive that calls for switching gasses is more along the lines of a > > "heavy deco" (your terminology) dive, where planning, including > > contingencies, is required before entering the water. Diving by computer > > is contraindicated for such dives. > > > Art Greenberg > > > artg@ec*.ne* >> > > > This, of course, is your opinion and I respect that. Remember please that I > > am definitely not suggesting doing extended deco dives at this time using > > only wrist computers and without having done the proper planning. But I need > > to emphasize again that although I personally don't recommend it, IMHO, the > > reasons that have been given for not using wrist computers simply do not seem > > to hold up under careful scrutiny. > > > Art, thanks a lot, really, for your comments. I do appreciate the > > opportunity to discuss this stuff and get some of the questions and concerns > > out in the open. > > > You take care now and safe diving, Scott >> >> -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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