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Scuba Forum / General / March 2005SCUBA-Air Integrated Computer choice---Which one of these three?
Looking at three Air Integrated computers: Sherwood Wisdom, Aeris ai, and Ocenaic Pro Plus 2 Deluxe. Pleas eshare which on you would own of these. TIA! -Pat > Looking at three Air Integrated computers: Sherwood Wisdom, > Aeris ai, and Ocenaic Pro Plus 2 Deluxe. Pleas eshare which on you > would own of these. TIA! UWATEC bottom timer and tables. Or a Suunto Vyper, if you must. "Scott" wrote >> Looking at three Air Integrated computers: Sherwood Wisdom, >> Aeris ai, and Ocenaic Pro Plus 2 Deluxe. Pleas eshare which on you >> would own of these. TIA! > > UWATEC bottom timer and tables. > > Or a Suunto Vyper, if you must. Hmmmm, cold water and warm water agree..... Curtis > Hmmmm, cold water and warm water agree..... Common sense of the Trailer Trash. The only time you introduce confusions and terror is when you involve the Bar. >Or a Suunto Vyper, if you must. How does the NDL time on a Vyper with the RBGM model compare to NDL from computers that use a Haldane-type model?  SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. >>Or a Suunto Vyper, if you must. > > How does the NDL time on a Vyper with the RBGM model compare to NDL from > computers that use a Haldane-type model? There was a good review of this on www.scubadiving.com with NDL times for the various computers, and I recall the RBGM Suunto model was the more conservative. Adam >>How does the NDL time on a Vyper with the RBGM model compare to NDL from >>computers that use a Haldane-type model? > There was a good review of this on www.scubadiving.com with NDL times for the various > computers, and I recall the RBGM Suunto model was the more conservative. There are rumors that scubadiving.com isn't the best source of info. From everything I could learn while considering a suunto recently, they're inherently more conservative than some, but I gather that the RGBM doesn't necessarily make a big difference. If you have a sawtooth profile and make a rapid ascent from 80 to 40 feet you'll see a penalty, but if you hit your max depth and make a gradual ascent the RGBM doesn't come into play nearly as much, if at all. Suunto's literature is heavy on marketing hype but a bit light on some of the specifics, but it seems to be clear that the profile will have a big impact on the degree of conservatism. I'd be interested in a side by side comparison of a Suunto and a few competing models for different profiles, but so far I haven't seen one. SignatureSteve The above can be construed as personal opinion in the absence of a reasonable belief that it was intended as a statement of fact. If you want a reply to reach me, remove the SPAMTRAP from the address. > I'd be interested in a side by side comparison of a Suunto and a few > competing models for different profiles, but so far I haven't seen one. Just dive with some Suunto divers on deeper profiles and see how quickly they call the dive. My Uwatec is also a pain in the a.s. You want long bottom times and don't mind a little risk, get a Cochran. > Just dive with some Suunto divers on deeper profiles and see how quickly > they call the dive. That is when they are in kind mood. In Wienke mode they just quit working and show a help screen: USE CRAY. My Uwatec is also a pain in the a.s. You want long > bottom times and don't mind a little risk, get a Cochran. I don't have future bonds. Matthias > > Just dive with some Suunto divers on deeper profiles and see how quickly > > they call the dive. [quoted text clipped - 6 lines] > > I don't have future bonds. You two are making me long for the days that I didn't have a computer. >You want long bottom times and don't mind a little risk, Greg is my hero. >get a Cochran. = Death. >>>How does the NDL time on a Vyper with the RBGM model compare to NDL from >>>computers that use a Haldane-type model? [quoted text clipped - 12 lines] > conservatism. I'd be interested in a side by side comparison of a Suunto and a few > competing models for different profiles, but so far I haven't seen one. Look at http://www.scubadiving.com/gear/dive_computers/dive_computer_secrets_revealed/1/ grouping of the various models by algorithm. There is also another page somewhere if you look, with simulated dives and NDL of the various several computers with the dive profiles. There is actually quite a difference in conservatism. When I get more time I'll try to find that web page. Although Rodale's likely does have some bias because of its advertising business, there is no reason to suspect that actual numbers in their studies have been altered. I don't think the kind of challenges I read from Force Fins really apply here. Adam >How does the NDL time on a Vyper with the RBGM model compare to NDL from >computers that use a Haldane-type model? Suunto Vyper is not now, and never has been "RGBM". The underlying model is Haldanean with Spencer M-values. The Halftimes and M-values are adjusted (occasionally) from internal tables and stimulated by observed events and pre-determined thresholds. "Suunto RGBM" != "RGBM". Not even *close*. bullshark safe diving, bullshark On Wed, 02 Mar 2005 02:17:15 +0000, spectrepjcook wrote: > Looking at three Air Integrated computers: Sherwood Wisdom, > Aeris ai, and Ocenaic Pro Plus 2 Deluxe. Pleas eshare which on you > would own of these. TIA! > > -Pat None. AI is not Scottish. > Looking at three Air Integrated computers: Sherwood Wisdom, > Aeris ai, and Ocenaic Pro Plus 2 Deluxe. Pleas eshare which on you > would own of these. TIA! > > -Pat I'd rather have my fingernails ripped out. Many experienced divers do not prefer AI. Usually people try to sell it to you because it's the most expensive thing in the dive shop. Having your tank pressure electronically delivered to you is really rolling the dice, amoung other concerns. > Many experienced divers do not prefer AI. Many experienced divers do not prefer computers at all. Use your head, they say. > Usually people try to sell it to you because it's the most expensive > thing in the dive shop. The most expensive isn't necessarily the worst. > Having your tank pressure electronically delivered to you is really > rolling the dice, amoung other concerns. Why? You eliminate problems that could otherwise happen to an HP hose and an analog pressure gauge. All my NDC info, depth, time, etc., are already electronically delivered to me, so why not tank pressure too? .. >> Having your tank pressure electronically delivered to you is really >> rolling the dice, amoung other concerns. > >Why? You eliminate problems that could otherwise happen to an HP hose and >an analog pressure gauge. All my NDC info, depth, time, etc., are already >electronically delivered to me, so why not tank pressure too? Having electronically delivered tank pressure gauges more problems than it eliminates -- and they are more likely to actually occure. HP hoses and analog pressure gauges have been prooven over many years to be *VERY* reliable. Electronic devices have many known problems: sometimes the sending unit on the tank fails to send; sometimes the gauge fails to recive. Sometimes the electronics end up being far less robust in a salt water environment that the analog devices the are trying to replace. As for loosing the NDC info, depth, time, etc... If you are within your NDL, you can just surface. (If you do NOT know how to make a safe, slow ascent without staring at a depth gauge, learn now.) If you have a decompression obligatio, you'd better have a backup plan in your head and backup insruments for (at least) depth and time. (I dive with a computer AND a bottom timer for this reason.) SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. > Having electronically delivered tank pressure gauges more problems > than it eliminates -- and they are more likely to actually occure. [quoted text clipped - 5 lines] > less robust in a salt water environment that the analog devices the > are trying to replace. Abacuses and slide rules were proven over many years to be very reliable, but the modern electronic calculator has completely replaced them. In the case of gauges, there's no difference in "computing" speed, but like a pocket calculator, AI computers are much more compact and convenient than analog. No hose that has to be clipped off: all the instrumentation is on the wrist or a retractor attached to the BC. Streamlined. Also, I've never had reliability issues with my AI computers. Obviously there haven't been too many reported since the manufacturers continue to make them and people continue to buy them. My Uwatec can switch between reading tank pressure on open circuit or inhalation hose PPO2 on a SCC rebreather. Can your analog gauge do that? > As for loosing the NDC info, depth, time, etc... If you are within your > NDL, you can just surface. (If you do NOT know how to make a safe, slow > ascent without staring at a depth gauge, learn now.) If you have a > decompression obligatio, you'd better have a backup plan in your head > and backup insruments for (at least) depth and time. > (I dive with a computer AND a bottom timer for this reason.) If you have a deco obligation, you should have planned this beforehand and have more than a "backup plan in your head". Analog gauges can't compensate for bad dive planning. > Abacuses and slide rules were proven over many years to be very reliable, > but the modern electronic calculator has completely replaced them. Not with me. I still use a 11" slide rule. It has never turned blue yet. Actually I am contemplating designing a mechanical divetime/depth interface equivalent to a mixture between a dive computer and a runtime table. Matthias >> Abacuses and slide rules were proven over many years to be very reliable, >> but the modern electronic calculator has completely replaced them. [quoted text clipped - 3 lines] > interface equivalent to a mixture between a dive computer and a runtime > table. I should know better and avoid absolute statements like that. There's always one in every bunch. A few of my neighbors still ride horses. Talk about obsolete. >>Not with me. I still use a 11" slide rule. It has never turned blue yet. >>Actually I am contemplating designing a mechanical divetime/depth [quoted text clipped - 4 lines] > always one in every bunch. A few of my neighbors still ride horses. Talk > about obsolete. How long does it take to power up the horses? Matthias >>> Abacuses and slide rules were proven over many years to be very reliable, >>> but the modern electronic calculator has completely replaced them. [quoted text clipped - 7 lines] >always one in every bunch. A few of my neighbors still ride horses. Talk >about obsolete. I have a flintlock. Signaturedillon "When the French are against it, you know we can't be far wrong." - Adm. Bobbie Ray Inman > I have a flintlock. Ahhh. Cant very well ban those, can they? Fired by a chip of rock. >> I have a flintlock. Here is a great analogy: Flintlock vs. Percussion Cap. The Precussion Cap rifle is a tecnological advance that made the rifle easier to use and more reliable. This is just the opposite of Air Integrated dive computers; these are more confusing and harder to use, as well as being clearly LESS reliable. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. >>>I have a flintlock. > [quoted text clipped - 4 lines] > dive computers; these are more confusing and harder to use, as well as > being clearly LESS reliable. MY AI is simple to use >>>>I have a flintlock. >> [quoted text clipped - 6 lines] >> >MY AI is simple to use I'm glad you think so. Good luck. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. >>>>>I have a flintlock. >>> [quoted text clipped - 8 lines] > > I'm glad you think so. Good luck. KNow so >> The Precussion Cap rifle is a tecnological advance that made the rifle >> easier to use and more reliable. This is just the opposite of Air [quoted text clipped - 3 lines] >> > MY AI is simple to use As are mine. The tank pressure reads in big digital numbers. I suppose it could be confusing to someone who's expecting a readout in bars, but that could only be a potential problem in locales accustomed to a majority of European divers. It's certainly no problem for the user and his buddy. I suppose the easily confused could mistake the tank pressure readout for the depth or temperature, but I don't usually dive with the easily confused. My Uwatec is the simplest. A little window, completely separate from the larger display, shows a number followed by 'psi'. To figure out how much air I have left, I simply glance at my wrist. Confusing and hard. > As are mine. The tank pressure reads in big digital numbers. I suppose it > could be confusing to someone who's expecting a readout in bars, but that > could only be a potential problem in locales accustomed to a majority of > European divers. It's certainly no problem for the user and his buddy. I've encountered some DM's that seemed to be confused by what my guages were reading . . . but reading my guages have never been a problem for me personally. A' course, I don' 've an AI, like my good dive buddy Greg. A' course, now that I unerstan 'ow ee's checkin' stuff, I unerstan (sic) why he was back on the boat and Curtis was wearin' me lika hat. Most of you guys had to be there to 'unerstan' that last sentence. > I suppose the easily confused could mistake the tank pressure readout for > the depth or temperature, but I don't usually dive with the easily confused. > > My Uwatec is the simplest. A little window, completely separate from the > larger display, shows a number followed by 'psi'. To figure out how much > air I have left, I simply glance at my wrist. Confusing and hard. If you believe in something that simple, why not just forego the whole device? I'm sorry(lo siento?), to you, one of my best of friends', but I'm starting to think that these depth timer guys have some kind of point. (wg) > A' course, now that I unerstan 'ow ee's checkin' stuff, I unerstan (sic) why > he was back on the boat and Curtis was wearin' me lika hat. > > Most of you guys had to be there to 'unerstan' that last sentence. Hmm, there was this psychiatrist Oliver Sacks who wrote a book " the man who confounded his wife with a hat" Matthias > A' course, now that I unerstan 'ow ee's checkin' stuff, I unerstan (sic) > why > he was back on the boat and Curtis was wearin' me lika hat. > > Most of you guys had to be there to 'unerstan' that last sentence. OK. I was there, I think. I don't understand it. Does that mean I'm easily confused? > If you believe in something that simple, why not just forego the whole > device? I'm sorry(lo siento?), to you, one of my best of friends', but > I'm > starting to think that these depth timer guys have some kind of point. I've done a few dives foregoing the whole device. As long as you know your starting gas and you have a bottom timer, a pressure gauge is just a crutch. Still, when I've been solo and gaugeless before, I've played it safe by sticking to 30'. > > A' course, now that I unerstan 'ow ee's checkin' stuff, I unerstan (sic) > > why [quoted text clipped - 4 lines] > OK. I was there, I think. I don't understand it. Does that mean I'm > easily confused? It may not mean you are easily confused . . .regardless, you are easily confused. > > If you believe in something that simple, why not just forego the whole > > device? I'm sorry(lo siento?), to you, one of my best of friends', but [quoted text clipped - 5 lines] > Still, when I've been solo and gaugeless before, I've played it safe by > sticking to 30'. How do you know you were only at 30'? > How do you know you were only at 30'? Because the book said so and my eyes confirmed it. I have enough experience diving at 30' that I can judge 30' (in clear water at least, with some visual references available) give or take 10' or so. > > How do you know you were only at 30'? > > Because the book said so and my eyes confirmed it. I have enough experience > diving at 30' that I can judge 30' (in clear water at least, with some > visual references available) give or take 10' or so. Then maybe you were at 40' or so. Good thing you also had some visual references. >> How do you know you were only at 30'? > > Because the book said so and my eyes confirmed it. I have enough > experience diving at 30' that I can judge 30' (in clear water at least, > with some visual references available) give or take 10' or so. Citizen Hyper Aqualand watch. > As are mine. The tank pressure reads in big digital numbers. I suppose it > could be confusing to someone who's expecting a readout in bars, but that > could only be a potential problem in locales accustomed to a majority of > European divers. It's certainly no problem for the user and his buddy. My Sherwood Wisdom can be set up for your choice of bars or psi and meters or feet. I have to beleive that this is not an uncommon feature. > I suppose the easily confused could mistake the tank pressure readout for > the depth or temperature, but I don't usually dive with the easily confused. These sort of confused people are just as likely to misread the depth/pressure on their analog guages > My Uwatec is the simplest. A little window, completely separate from the > larger display, shows a number followed by 'psi'. To figure out how much > air I have left, I simply glance at my wrist. Confusing and hard. It's the big numbers on the bottom of the Sherwood as well. >> As are mine. The tank pressure reads in big digital numbers. I suppose >> it could be confusing to someone who's expecting a readout in bars, but [quoted text clipped - 4 lines] > My Sherwood Wisdom can be set up for your choice of bars or psi and meters > or feet. I have to beleive that this is not an uncommon feature. No, it's certainly not uncommon. But if I did that, I would confuse myself, and then I'd be likely to lose the manual and be stuck on bars for ever. > These sort of confused people are just as likely to misread the > depth/pressure on > their analog guages If you're upside down and dyslexic, doesn't an empty tank read full? > > These sort of confused people are just as likely to misread the > > depth/pressure on > > their analog guages > > If you're upside down and dyslexic, doesn't an empty tank read full? Yes, but usually only once. >>>As are mine. The tank pressure reads in big digital numbers. I suppose >>>it could be confusing to someone who's expecting a readout in bars, but [quoted text clipped - 13 lines] > > If you're upside down and dyslexic, doesn't an empty tank read full? on >> If you're upside down and dyslexic, doesn't an empty tank read full? Only if the gauge somehow remained right side up. If it is also upside down it will read correctly. <grin> SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. >> MY AI is simple to use > >As are mine. The tank pressure reads in big digital numbers. ... WOW! B_I_G disconnect here! Designers of instument displays are well aware that DIGITAL displays are harder and take longer to read than ANALOG displays. This is seen in the aircraft industy where modern digtal instuments presnet an ANALOG display -- on a video display screen. After a few dives you know instinctively what it means when an SPG needle point in a particular way. If all you have is a NUMBER, you have to read and interpret it -- Reading numbers is more error prone that noting the position of a needle, and interpetin those numbers is also error prone. We all love to see information presented in graphs, bar chars, pie charts, etc. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. > Designers of instument displays are well aware that DIGITAL displays > are harder and take longer to read than ANALOG displays. This is seen > in the aircraft industy where modern digtal instuments presnet an > ANALOG display -- on a video display screen. I see what you mean. That extra 2 milliseconds that it takes me to glance at my DIGITAL display might make me miss a shark or something. But since I make up 5 milliseconds by being able to glance at my wrist, it's more than a wash. My Casio G-Shock watch unfortunately gives me a digital-only readout. Next time someone asks me what time it is, I'll tell them I don't have time to look. After all, time is money. > After a few dives you know instinctively what it means when an SPG > needle point in a particular way. If all you have is a NUMBER, you > have to read and interpret it -- Reading numbers is more error prone > that noting the position of a needle, and interpetin those numbers > is also error prone. Yup. When I see 2,500 it always takes me a few minutes to think about what the 2 the 5 the 0 and the other 0 have to do with one another. Let's see, the 2 is in the thousands column, the 5 is in the hundreds column, the first 0 is in the tens column, and the last 0 is in the one's column. 2,000 + 500 + 0 + 0 = 2,500. That took a lot of time to figure out. Funny I never noticed it before. Did you have problems in math classes when you were a child? I bet you liked when the teacher would explain math by using an ANALOG clock. > We all love to see information presented in graphs, bar chars, pie charts, > etc. Really? Charts disgust me. I grew out of picture books before I hit puberty and discovered picture magazines. But then I never had a problem reading and interpreting simple numbers. >>>MY AI is simple to use >> [quoted text clipped - 14 lines] > > We all love to see information presented in graphs, bar chars, pie charts, etc. I've never misread mine - it works great both Nitrox and Non enriched, multi level, have no problem understanding the numbers, it does a great job of giving me an estimated remaining air time. I guess I just don't understand having trouble understanding the data presented to you. > ... I guess I just don't >understand having trouble understanding the data presented to you. Yes, that is obvious. If you don't understand the trouble it is hard for me to see how you can be so certain that you aren't having it -- and just not recognizing the issue. But since I don't know how to show you the issue any better than I already have, I think I'll just stop trying. Happy, safe diving! SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. >> ... I guess I just don't >>understand having trouble understanding the data presented to you. [quoted text clipped - 9 lines] > > Happy, safe diving! Never had a decompression problem, never ran out of air, always enjoy safe diving. Guess, as most of the divers here, we are able to read the data, understand the data. and make choices based on the data. Don't understand the issue you are trying to prove. Maybe there just isn't one. >>>MY AI is simple to use >> >>As are mine. The tank pressure reads in big digital numbers. ... > > WOW! B_I_G disconnect here! The key word is BIG. The hose isn't long enough nor my arms long enough to read a small gauge (or computer) without my reading glasses :-) >>>> MY AI is simple to use >>> [quoted text clipped - 5 lines] > arms long enough to read a small gauge (or computer) without > my reading glasses :-) Get the little inserts - they fit in the bottom of your mask (i only have one in my left lens - works great. > Get the little inserts - they fit in the bottom of your mask (i only have > one in my left lens - works great. I'm finally going to have to do that. I bought a new computer. Key data numbers are all large enough for me to see without assistance, but the small stuff isn't. I violated the computer's preferred PPO2 (1.4) by a very small amount and one of the smaller parts of the display flashed at me for the remainder of the dive. Since I could not read what was flashing, I spent the rest of the dive wondering what the computer was trying to warn me about. It was not until I returned to the surface where I had access to both my reading glasses and computer manual that I figured it out. Lee >>Get the little inserts - they fit in the bottom of your mask (i only have >>one in my left lens - works great. > > I'm finally going to have to do that. I bought a new computer. Key data > numbers are all large enough for me to see without assistance, but the small > stuff isn't. I can still read my computer with no problem, but the ocean is full of lots of interesting stuff that's really small, and as my eyesight has gotten worse I've gotten more interested in the small stuff. I definitely need to see about mask inserts in the near future. Simple magnification will probably do the trick, but I'll also check on real lenses from an optician. SignatureSteve The above can be construed as personal opinion in the absence of a reasonable belief that it was intended as a statement of fact. If you want a reply to reach me, remove the SPAMTRAP from the address. > >>Get the little inserts - they fit in the bottom of your mask (i only have > >>one in my left lens - works great. [quoted text clipped - 8 lines] > inserts in the near future. Simple magnification will probably do the trick, but I'll > also check on real lenses from an optician. I got a great magnifying glass when I was in Sipadan. I carry it in my BC pocket and make a lot of use of it. One of my best purchases to date. I think it cost me around $7. > Get the little inserts - they fit in the bottom of your mask (i only > have one in my left lens - works great. Thought of that, but I can read the Wisdom displays just fine, and I doubt I'll be reading any other fine print. > Thought of that, but I can read the Wisdom displays just fine, and > I doubt I'll be reading any other fine print. You're lucky. Half the shells I see down there have "Made in Taiwan" etched in really, really small lettering. > Designers of instument displays are well aware that DIGITAL displays > are harder and take longer to read than ANALOG displays. Fine, but how much harder? In the case of tank pressure it's not a very big or confusing number. If it's too hard you're either too deep for the mix you're using or too easily confused to be diving. > We all love to see information presented in graphs, bar chars, pie charts, etc. Fortunately, the pressure display on a digital readout *is* a bar graph if they don't clutter things with an unnnecessary zero. In the case of cylinder pressure I'd have to say the metric system has the edge here. SignatureSteve The above can be construed as personal opinion in the absence of a reasonable belief that it was intended as a statement of fact. If you want a reply to reach me, remove the SPAMTRAP from the address. > >> I have a flintlock. > [quoted text clipped - 4 lines] > dive computers; these are more confusing and harder to use, as well as > being clearly LESS reliable. disagree. my console has pressure, depth, and compass. my regulator also has a pressure transmitter, so my computer has a backup. it also automatically switches between ND time and air time. It allows me to dive an ascending profile along the reef that minumizes nitrogen loading, and maximizes dive time. > -- > Charlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA > (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) > All opinions expressed are my own and not necessarily my employer's. >my console has pressure, depth, and compass. >my regulator also has a pressure transmitter, >so my computer has a backup. Backup for a computer is an excellent idea. I use a non-AI computer and a bottom timer, so I have backup for everything except NDL time. Of course I don't have backup for my analog depth gague and don't feel I need it. >it also automatically switches between ND time and air time. A terrible idea! SOOOOOO easy to loose track of what you're seeing now. >It allows me to dive an ascending profile along the reef >that minumizes nitrogen loading, >and maximizes dive time. You don't need a computer to do this -- much less and AI computer. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. > >my console has pressure, depth, and compass. > >my regulator also has a pressure transmitter, [quoted text clipped - 10 lines] > A terrible idea! > SOOOOOO easy to loose track of what you're seeing now. not a problem for me. air use and air remaining is usefull to me. > >It allows me to dive an ascending profile along the reef > >that minumizes nitrogen loading, > >and maximizes dive time. > > You don't need a computer to do this -- much less and AI computer. true. its just easier and better with AI. > -- > Charlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA > (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) > All opinions expressed are my own and not necessarily my employer's. > It allows me to dive an ascending profile along the reef > that minumizes nitrogen loading, That is a misconception, if you talk about about sliding along the NDC-Limit on ascent. Matthias > > It allows me to dive an ascending profile along the reef > > that minumizes nitrogen loading, > > That is a misconception, if you talk about about sliding along the > NDC-Limit on ascent. I do not. > Matthias >> It allows me to dive an ascending profile along the reef that >> minumizes nitrogen loading, [quoted text clipped - 3 lines] > > Matthias That's a pretty common practice. What's wrong with it? m >>> It allows me to dive an ascending profile along the reef that >>> minumizes nitrogen loading, [quoted text clipped - 5 lines] > > That's a pretty common practice. What's wrong with it? Provided we both mean the same, e.g. waiting till your computer gives a NDC warning, then ascending till it gives credit for a couple of minutes, then warns again, you ascend again, and so on. It is blade running and accumulating all the errors and mismatches your computers is up to. It leaves you with a false sense of security ( thinking there is no deco obligation when there may be very well one) Matthias >>>> It allows me to dive an ascending profile along the reef that >>>> minumizes nitrogen loading, [quoted text clipped - 16 lines] > > Matthias I wonder.... That is, of course, the old ascent profile (pre-Haldane), just pull 'em up slowly, and the Haldanian system of half-pressure stops definitely reduced DCS. But modern dive computers are so freakin conservative, I really don't think it makes a difference. But it's worth discussion. And it's interesting that the computer has restored the pre-Haldane ascent profile for a lot of divers, me included. I suspect that the majority of wall diving is to the NDL with a "blade running" ascent up the wall. m >> Provided we both mean the same, e.g. waiting till your computer gives >> a NDC warning, then ascending till it gives credit for a couple of [quoted text clipped - 12 lines] > up slowly, and the Haldanian system of half-pressure stops definitely > reduced DCS. Now that you mention it.... Right, that is exactly the old style method favoured by Hill... Later proven to give a lot mor deompression problems than the staged decompression. > But modern dive computers are so freakin conservative, I really don't > think it makes a difference. To me it makes a difference in the way I feel. I definitely feel "cleaner" after a deeper decompression dive with deep stops, compared to a medium depth ND- dive with a gradual ascent. > But it's worth discussion. And it's interesting that the computer has > restored the pre-Haldane ascent profile for a lot of divers, me > included. Indeed. But proclaiming a staged ascent with respect to Haldane e.a., would put this kind of diving into the "dangerous" vicinity of decompression dives, which are to give reason for an emergency ascent to "most divers". And it probably would deprive the computer industry of the possibility to introduce all those ever new gadgets and mirror their fantastic, thorough studies and concerns. I suspect that the majority of wall diving is to the NDL with > a "blade running" ascent up the wall. Which was considered with due reason as extending the bottom time till the first real stop by old table rules. Matthias > >>> It allows me to dive an ascending profile along the reef that > >>> minumizes nitrogen loading, [quoted text clipped - 9 lines] > NDC warning, then ascending till it gives credit for a couple of > minutes, then warns again, you ascend again, and so on. sort of a dumb use to me. that is maximizing, not minumizing Nitrogen loading. > Matthias >>>That's a pretty common practice. What's wrong with it? >> [quoted text clipped - 4 lines] > sort of a dumb use to me. > that is maximizing, not minumizing Nitrogen loading. Yes and no. You maximize loading of the faster compartments, then offgas from those as you load ever slower compartments, and the chain goes on. Stage deco skips links in the chain to the half-pressure link, then starts again. Deco theorists are still arguing about why the latter is more effective than the former, but no one argues that staged deco is not better. My argument is that, because even the most aggressive computers keep you so far inside the NDL, the slow steady ascent riding the computer's NDL is prolly as safe as it gets. Or maybe I'm just trying to rationalize my own bad habits... > >>>That's a pretty common practice. What's wrong with it? > >> [quoted text clipped - 9 lines] > the chain goes on. Stage deco skips links in the chain to the > half-pressure link, then starts again. thanks. now I see what you propose. in practice, at the surface, would you rather have loaded fast compartments or slow? any particular risk level associated with either? > Deco theorists are still arguing about why the latter is more > effective than the former, but no one argues that staged deco is [quoted text clipped - 5 lines] > > Or maybe I'm just trying to rationalize my own bad habits... > in practice, at the surface, > would you rather have loaded fast compartments or slow? > any particular risk level associated with either? It kind of depends on the basis for your preference. If you mean, relative to DCS risk, it's more or less a draw over the short term. If you haven't loaded tissues beyond what they will safely sustain at the surface, you're not bent. Not bent is not bent. Fast tissues both on and off gas faster than slower ones. The load you have in slow tissues sticks with you longer than those you have in the faster ones. If you could load only fast tissues, you'd have more bottom time or a shorter no fly time than if you loaded only slow tissues. Unfortunately, life's not that easy. You get some load in all tissues and none of the tissues offgasses at a constant rate. A highly loaded tissue, due to larger pressure differentials, offgasses quicker than the same tissue at a lower level. The variation in the same tissue as the PPN2 changes is precisely why half times are used for calculations. The same half time, at differrent PPN2 levels, results in different degrees of change over time. Lee > > in practice, at the surface, > > would you rather have loaded fast compartments or slow? [quoted text clipped - 4 lines] > loaded tissues beyond what they will safely sustain at the surface, you're > not bent. Not bent is not bent. it would seem that slow compartments become more significant when you are looking at no fly interval. > Fast tissues both on and off gas faster than slower ones. The load you have > in slow tissues sticks with you longer than those you have in the faster [quoted text clipped - 8 lines] > > Lee >> It kind of depends on the basis for your preference. If you mean, >> relative [quoted text clipped - 6 lines] > it would seem that slow compartments become more significant > when you are looking at no fly interval. Only if your hair is dry. >>>It kind of depends on the basis for your preference. If you mean, >>>relative [quoted text clipped - 8 lines] > > Only if your hair is dry. I will have no problemo! > Provided we both mean the same, e.g. waiting till your computer gives a > NDC warning, then ascending till it gives credit for a couple of [quoted text clipped - 6 lines] > > Matthias Hell, that's the only way I -ever- dive. What the hell else is the computer for? I ride mine up and down like a dirtbike. >>NDC warning, then ascending till it gives credit for a couple of >>minutes, then warns again, you ascend again, and so on. [quoted text clipped - 17 lines] > > I ride mine up and down like a dirtbike. It depends on the type of dive. Still I do not redescend much, mostly. Depends on the nitrogen load as well, of course. Matthias >>> Abacuses and slide rules were proven over many years to be very reliable, >>> but the modern electronic calculator has completely replaced them. >> >> Not with me. I still use a 11" slide rule. It has never turned blue yet. .. I pulled my 40 year old slide rule out of my bottom desk drawer last night. It still works. More amazing is that I still remember how to use it. (I need the manual in hand to access some of my dive computer's functions!) Meanwhile, the less-than-two-year-old electronic calculator on my desk is dying -- dead segments in the display. Yes, there are reasons for electronic devices, but the reality is that a well-made mechanical device can be expected to outlive a similarly well made electronic device. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. >>>>Abacuses and slide rules were proven over many years to be very reliable, >>>>but the modern electronic calculator has completely replaced them. [quoted text clipped - 13 lines] > well-made mechanical device can be expected to outlive a similarly well > made electronic device. except that your calculator is probably not "well made" but rather cheaply made. Were you willing to pay the price, a calculator could be engineered to last nearly forever. $0 years ago, that was probably the design criteria for the slide rule. Not so in today's market for electronics. SignatureThe constitution promises freedom OF religion, not freedom FROM religion. Think about it, It ain't that hard to figure out. If your religion is none, then deal with it. I strongly urge everyone reading this to check out WWW.anysoldier.com, and support our troops with a letter, a package or a donation. > > I pulled my 40 year old slide rule out of my bottom desk drawer last night. > > It still works. More amazing is that I still remember how to use it. [quoted text clipped - 12 lines] > design criteria for the slide rule. Not so in today's market for > electronics. And if he'd been using the slide rule daily for 40 years, I'll bet it would be pretty sloppy, hard to read, and ready to be replaced. >> Meanwhile, the less-than-two-year-old electronic calculator on my desk >> is dying -- dead segments in the display. > except that your calculator is probably not "well made" but rather > cheaply made. Were you willing to pay the price, a calculator could be > engineered to last nearly forever. $0 years ago, that was probably the > design criteria for the slide rule. Not so in today's market for > electronics. The cynic in me is a bit concerned, but my more optimistic side thinks that the average dive computer will be a bit more reliable than a $5 calculator. If nothing else, the corporate lawyers probably warn them that the potential consequences of failure may be more serious than an angry letter here and there. OTOH, when my TI scientific calculator (about $200 when I graduated high school) died after 15 years or more I replaced it with a $10 Casio. The casio must be at least 10 years old, and not only is it still working, it still has the original batteries. On a slightly related note, the remote for my Yamaha CD player is still working with the original batteries. The first CD I ever bought was Pink Floyd' Momentary Lapse of Reason, and it was a recent release, so those batteries are from about 1987. The electronics are still fine, but the CD tray doesn't always wabt to open. I'd say the tray is the CD player's analog (as it were) to the mechanical SPG's some of you think are so much more reliable than electronic instrumentation. SignatureSteve The above can be construed as personal opinion in the absence of a reasonable belief that it was intended as a statement of fact. If you want a reply to reach me, remove the SPAMTRAP from the address. > > Having electronically delivered tank pressure gauges more problems > > than it eliminates -- and they are more likely to actually occure. [quoted text clipped - 4 lines] > Abacuses and slide rules were proven over many years to be very reliable, > but the modern electronic calculator has completely replaced them... They're merely different tools to do similar jobs. > Also, I've never had reliability issues with my AI computers. For most people, the same can be said about their hose reliability too. But what this doesn't resolve is that if there are any differences in their failure modes that makes the one a better choice over the other: of two otherwise equally reliable systems, a difference in how it fails may result in a logical objective criteria for why one may be preferred over the other. Indeed, this factor may even be significant enough to overrule reliability differences such that the less reliable could become the preferred choice! > Analog gauges can't compensate for bad dive planning. And neither can fancy electronics. FWIW, my short answer to the OP is "none of the above". Generally speaking, many rec divers use dive computers because it allows a way to increase bottom time through easy multi-level diving. As such, this can boil down to a "bang for the buck" pragmatic approach, where if a $200 non-AI dive computer allows a +X% gain in bottom time, an AI dive computer that costs twice as much would have to deliver twice as much of a gain in bottom time to proverbially "break even". -hh >Also, I've never had reliability issues with my AI computers. ... I doubt that your experience it typical. I've had a computer develop a leak. I've had batteries fail the day before a dive trip. I surely don't think I'm the only one. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. > ... AI computers are much more compact and convenient than >analog. No hose that has to be clipped off ... Streamlined. If you are unable to route the HP hose from your tank to your SPG, you have some learning to do. This is simply NOT an issue -- other than working your way up a learning curve that is a lot shorter and less steep that then learning curve for an electronic SPG or air-itegrated computer. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. > If you are unable to route the HP hose from your tank to your SPG, > you have some learning to do. Not me. I don't have an HP hose. > Having electronically delivered tank pressure gauges more problems > than it eliminates -- and they are more likely to actually occure. Every feature that gets added to a computer adds a possible failure point, but what are the realistic chances of failure and what are the probably failure modes? I promise that AI isn't a big one. > HP hoses and analog pressure gauges have been prooven over many years > to be *VERY* reliable. Electronic devices have many known problems: > sometimes the sending unit on the tank fails to send; sometimes the > gauge fails to recive. I don't know about the other computers the OP is considering, but the Oceanic isn't hoseless. > Sometimes the electronics end up being far > less robust in a salt water environment that the analog devices the > are trying to replace. That's an excellent point, and for that reason I strongly urge the OP to make sure he gets one of them *waterproof* computers. > As for loosing the NDC info, depth, time, etc... If you are within your > NDL, you can just surface. Anybody who's doing recreational diving and wants to maximize their dive time would be silly not to use a computer. Personally I don't see much advantage to an AI computer, and I definitely don't see a $200 to $400 advantage, but that strikes me as a much more sensible criteria than the very slight increase in the possibility of a failure. If your computer fails it's close to time to surface, anyway, so not knowing your air pressure isn't really a big deal. >If you have a > decompression obligatio, you'd better have a backup plan in your head > and backup insruments for (at least) depth and time. You should read "Caverns Measureless to Man" and see how to deal with a minor deco obligation after you've lost your timing device. You can also learn what kind of bottom timer Exley found to be the most reliable on really deep dives. SignatureSteve The above can be construed as personal opinion in the absence of a reasonable belief that it was intended as a statement of fact. If you want a reply to reach me, remove the SPAMTRAP from the address. > Every feature that gets added to a computer adds a possible failure > point, but what are the realistic chances of failure and what are the > probably failure modes? I promise that AI isn't a big one. But risk is not equal to probability of failure mode. It is the product of probability times associated consequences. Matthias >Every feature that gets added to a computer adds a possible failure point, >but what are the realistic chances of failure and what are the probably >failure modes? I promise that AI isn't a big one. The realistic changes of failure approach 100% -- but that is a pretty meaningless statistic. I do agree that the failure rate for AI vs non-AI is probably not significantly different, but the failure mode -- loss of SPG info -- is more serious for AI. But the biggest reason to avoid AI dive computes is not the simple tank pressure information. Rather it is the air-time-remaining calculations that the attemtp to do. These are always wrong and can be very missleading. The computer simply does not know you dive plan and cannot therefore predict your future (for the rest of the dive) air use. So divers quickly learn to ignore this information. Better to my way of thinking to just not have the wrong information. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. >>Every feature that gets added to a computer adds a possible failure point, >>but what are the realistic chances of failure and what are the probably [quoted text clipped - 14 lines] > learn to ignore this information. Better to my way of thinking to just > not have the wrong information. I find the air time remaining quite helpful, the same situation exists with analog, it can not predict the future, mine is quite accurate. AI is like any other tool, if you use correctly, and don't let it do things or skew your decisions based on misinterpretation of the data all is fine. >I find the air time remaining quite helpful, ... So do I. I get correct air time remaingng by processing the reading of my SPG and my dive plane through the computer between my ears! > ... the same situation exists with analog... Huh? What ANALOG computer/guge shows air time remaining???? >AI is like any other tool, if you use correctly, and don't let it do things >or skew your decisions based on misinterpretation of the data all is fine. You are confusing DATA with INFORMATION. AI computers process data to provide INCORRECT information about air time remaining. As I have already said, it is easier and safer not to have the information if it is incorrect. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. > As I have already said, it is easier and safer not to have the information > if it is incorrect. Not at all. It's merely a guideline, often helpful. Just like it's nice that our government gives us colorful warnings of impending terrorist attacks even though they're most often incorrect. I can't see how not knowing that we're at Orange Level makes life any safer or easier. For multi-level diving, it's not so bad. While I roughly know my SAC, as variable as that may be, and I can pretty much "eyeball" how much time I have at a certain depth, having the computer tell me that because I've been breathing hard working against a current that I only have 10 minutes of air left rather than the 20 I would otherwise have calculated in my head makes a very pertinent difference. In doing one's own SAC calculations, one always has to include variables like temperature and depth and level of 'work'. But if I've been kicking hard, then relaxing, going from 90' to 70' then back to 90' for a short while kicking against the current, then ending up at 50' for the rest of my dive, meanwhile wearing my new full 3mm which doesn't have the same thermal protection of my 5mm but today it's 78 in the water, not 75, I'd rather trust a computer to give me an on-the-spot diagnosis of exactly what I'm breathing rather than try to figure it out in my own narced head. Of course I can quickly reconcile that information with what's actually in the tank and with my own personal experience. Maybe your argument is that new divers shouldn't use AI computers because they have nothing with which to compare the results, but for an experienced diver they're just another helpful tool. > For multi-level diving, it's not so bad. While I roughly know my SAC, as > variable as that may be, and I can pretty much "eyeball" how much time I [quoted text clipped - 10 lines] > exactly what I'm breathing rather than try to figure it out in my own narced > head. That's fine for you. I tend not to do multilevel dives, and the most significant information as well as single point of dive planning is " go retour at 130 bar ( of 200), with a single 15l bottle. This leads to having done a decompression completed after one hour into the dive, regardless of depth, and tehn having a headroom of about 10-15 minutes. Matthias > That's fine for you. > I tend not to do multilevel dives, What the heck do you mean that you don't tend to do multi-level dives? You go down, you go across, you ascend? You are a PADI protege? I'm afraid I don't understand your lingo and probably wouldn't understand this statement, even if my next door neighbor wrote it. Still, I'll accept that it is a cultural misunderstanding. >nd the most significant information > as well as single point of dive planning is " go retour at 130 bar ( of > 200), with a single 15l bottle. > This leads to having done a decompression completed after one hour into > the dive, regardless of depth, and tehn having a headroom of about 10-15 > minutes. > > Matthias >>That's fine for you. >>I tend not to do multilevel dives, > > What the heck do you mean that you don't tend to do multi-level dives? You > go down, you go across, you ascend? You are a PADI protege? Whoops. I can't even spell four letter words.... But since you feel a need for an explanation of the profiles I do: Deep down first.. sounds familiar, huh? Exploring what there is, with a tendency of moving slightly upwards. When 130 bars are remaining, I specify my first deep stop with the help of my VR3. This may be at typically 48-38m in the mediterranean. At the first or scnd deep stop I calculate my remaining air time based on my consumption, averaged mean depth of the remaining part of the dive, just in case I stretched the bottom time to, say, 115 bar. The rest of the depth profile is monotonously shallower, with the exception of decompression stops. Call that any way you like, obviously the levels are multi enough, if you chose a small enough time segment. Anyway I don't keep my eyes shut when doing decompression, since between 11m and surface there are interesting things to see, if you happen to dive a reef like that. What I do not like, is terrain following in a dive where you have, or some idjet dictates a "multilevel" profile consisting of two major parts where you spent bottom time. I think it disturbs a good decompression, and you feel like sh.t afterwards. The profiles I do make me feel well afterwards, and there printout looks equally nice. As if designed by *** who must not be mentioned ;-) Matthias > That's fine for you. > I tend not to do multilevel dives, and the most significant information as [quoted text clipped - 3 lines] > the dive, regardless of depth, and tehn having a headroom of about 10-15 > minutes. Sounds boring. I prefer a little variety in my diving. No, make that I prefer a lot of variety in my diving. >>That's fine for you. >>I tend not to do multilevel dives, and the most significant information as [quoted text clipped - 6 lines] > Sounds boring. I prefer a little variety in my diving. No, make that I > prefer a lot of variety in my diving. Unfortunately in the mediterranean you often find the median ( a french term) zone between -13 to -35-40m covered with slime and algae. You have to go below the thermocline. For the variety as well, as there is still some- No, a lot really. Unless you drop down to endless fields of black or red corall, which may happen if you know where to go. Matthias >>>with a single 15l bottle. >> Sounds boring. I prefer a little variety in my diving. No, make that I >> prefer a lot of variety in my diving. [quoted text clipped - 3 lines] > You have to go below the thermocline. For the variety as well, as there is > still some- No, a lot really. No wonder you bring the bottle of 151, to alleviate the boredom and warm you up. Is the slime and algae edible there, or only in France? > No wonder you bring the bottle of 151, to alleviate the boredom and warm you > up. [OT] What do the numbers really stand for? A weird unit ratio? the spanish have this 103 Brandy, good to mix into the coffee, so a 151 is stronger ? > Is the slime and algae edible there, or only in France? One guy tried the french atlantic variety, after having read that they harvest 6 different kinds. The next day his skin was covered with red pimples ;-) Beyond that stuff mentioned above, there are places where the caulerpa taxifolia ( killer algae) cover vast areas, down to 45 m, suffocating everything below. Matthias > > No wonder you bring the bottle of 151, to alleviate the boredom and warm you > > up. > > [OT] What do the numbers really stand for? A weird unit ratio? the > spanish have this 103 Brandy, good to mix into the coffee, so a 151 is > stronger ? In the case of 151, it stands for the proof. As far as the 103 Brandy, I'd guess it's the same thing, but I don't know that for sure. Just in case it's different elsewhere, proof is a measurement of alcohol. Divide the proof in half and you have the % alcohol by volume (so 151 is 151 proof or 75.5% alcohol by volume). >>[OT] What do the numbers really stand for? A weird unit ratio? the >>spanish have this 103 Brandy, good to mix into the coffee, so a 151 is [quoted text clipped - 6 lines] > Divide the proof in half and you have the % alcohol by volume (so 151 is 151 > proof or 75.5% alcohol by volume). Thanks for making me wonder again ;-) So some people understand bigger numbers better? Why not multiply by ten ? 151 is quite strong stuff, then. Had a 140 proof vodka once... used it to make spice liquor. Matthias |
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