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Scuba Forum / General / September 2006Anyone still use Dive tables?
Was working my way through my course work last night and finally figured out the dive table for repetitive dives, I THINK. but can anyone explain to me what, on the third table, is the lower number used for e.g. 25/135. I understand using 25 plus your dive time to get your new group BUT what do you use the lower number for??? Also how many people still use the dive table? or do you really on your computer? I was thinking that even if the table says 50 min at your depth it's more important to watch you SPG?? Right or wrong? Newbie... > Was working my way through my course work last night and finally figured > out the dive table for repetitive dives, I THINK. but can anyone explain [quoted text clipped - 7 lines] > > Newbie... Take a class. You'll learn all this stuff. Taking a class hence the reason I ask. Wonder what real world experience is? I find like most courses there is the "theory" and then there's the "practice". >> Was working my way through my course work last night and finally figured >> out the dive table for repetitive dives, I THINK. but can anyone explain [quoted text clipped - 9 lines] > > Take a class. You'll learn all this stuff. > Was working my way through my course work last night and finally figured > out the dive table for repetitive dives, I THINK. but can anyone explain > to me what, on the third table, is the lower number used for e.g. 25/135. > I understand using 25 plus your dive time to get your new group BUT what > do you use the lower number for??? It took me a while, but I finally found a PADI table I could read . . . sort of. I still didn't find 35/135, but I think I found what you're looking at. If so, the information you are looking for is on the lower right hand portion of the tables. If what you're looking at is what I'm looking at, the 135 is the maximum no decompression time for the repetitive dive depth you selected. Lee > Taking a class hence the reason I ask. Wonder what real world experience > is? I find like most courses there is the "theory" and then there's the > "practice". In theory, we don't top-post here. In practice, we don't either. >>> Was working my way through my course work last night and finally figured >>> out the dive table for repetitive dives, I THINK. but can anyone explain >>> to me what, on the third table, is the lower number used for e.g. >>> 25/135. I understand using 25 plus your dive time to get your new group >>> BUT what do you use the lower number for??? Real-world, or theory? Take the class first. >>> Also how many people still use the dive table? or do you really on your >>> computer? I was thinking that even if the table says 50 min at your >>> depth it's more important to watch you SPG?? Right or wrong? It's always important to check your SPG. It's always important to dive according to your tables or computer. Failure to do one or the other can lead to death, so they're equally important. Most avid recreational divers (i.e. divers that own their own gear and use it) use computers because they are much more practical than tables. Some avid recreational divers who also tech dive claim to be able to dive recreationally without using computers, but the rest of us are just waiting for them to get bent so we can say we told you so. In theory and practice, I do. You don't have to scroll as far to find what I wanted you to know. > In theory, we don't top-post here. In practice, we don't either. > In theory and practice, I do. You don't have to scroll as far to find > what I wanted you to know. > >> In theory, we don't top-post here. In practice, we don't either. Lee are you voting for top posting or against it? I prefer reading top posting because I've already read every message before it... I thinks it's anoyying scrolling through three pages just to read a "LOL" or something similar. I rarely top post, for brevity, but most of our threads, the vast majority, proscribe it due to the length of the text. Top posting will cause great confusion.  SignaturePopeye Listen, strange woman lying in ponds distributing swords is no basis for a system of government. Monty Python www.finalprotectivefire.com >> In theory and practice, I do. You don't have to scroll as far to find >> what I wanted you to know. [quoted text clipped - 5 lines] > annoying scrolling through three pages just to read a "LOL" or something > similar. Only a.sholes top post. > I rarely top post, for brevity, but most of our threads, the vast > majority, proscribe it due to the length of the text. [quoted text clipped - 10 lines] >> it's annoying scrolling through three pages just to read a "LOL" or >> something similar. How cool is -that-? SignaturePopeye You can get much further with a kind word and a gun than you can with a kind word alone. -Capone www.finalprotectivefire.com > Only a.sholes top post. > [quoted text clipped - 12 lines] >>> it's annoying scrolling through three pages just to read a "LOL" or >>> something similar. > Only a.sholes top post. Personally, I prefer side posting. m > [quoted text clipped - 12 lines] >>>it's annoying scrolling through three pages just to read a "LOL" or >>>something similar. > Lee are you voting for top posting or against it? I prefer reading top > posting because I've already read every message before it... I thinks it's > anoyying scrolling through three pages just to read a "LOL" or something > similar. I tend to prefer the inline comment posting style, but it only works if you are willing to edit the previous post so that only the minimum necessary is left there... For the typical "LOL" reply, just trim the entire message other than the header to a simple "<snip>" and then put your one-liner type reply after it... At least this way, we know who you are replying to and even perhaps when the previous message was posted... Removing the crosspostings in your reply is also good... I thinks it's > anoyying scrolling through three pages just to read a "LOL" or something > similar. Thats when you snip out stuff that you are not replying to! bernard >> Taking a class hence the reason I ask. Wonder what real world experience >> is? I find like most courses there is the "theory" and then there's the [quoted text clipped - 23 lines] > recreationally without using computers, but the rest of us are just > waiting for them to get bent so we can say we told you so. Greg sorry for top posting but I honestly find it nicer to clear out all of the "old" text" and then write the reply, I'll try to remember to bottom post here. When you said that you were waiting for the tech divers to get bent I assumed you were looking to buy some used equipment... > Greg sorry for top posting but I honestly find it nicer to clear out all > of the "old" text" and then write the reply, I'll try to remember to > bottom post here. When you said that you were waiting for the tech divers > to get bent I assumed you were looking to buy some used equipment... I'd have no use for it. They use computers that don't compute and wear some funky contraption made out of used seatbelts and what looks to be a piece of a car door. > Some avid recreational divers who also tech dive claim to be able to dive > recreationally without using computers, but the rest of us are just > waiting for them to get bent so we can say we told you so. Be right behind the overweight, smoking, hung-over wrong gas divers in the bent line....... Curtis >> Some avid recreational divers who also tech dive claim to be able to dive >> recreationally without using computers, but the rest of us are just >> waiting for them to get bent so we can say we told you so. > > Be right behind the overweight, smoking, hung-over wrong gas divers in > the bent line....... Is it me.......or was that sarcasm??? LD. >>> Some avid recreational divers who also tech dive claim to be able to >>> dive recreationally without using computers, but the rest of us are just [quoted text clipped - 4 lines] >> > Is it me.......or was that sarcasm??? Definitely dripping with saccasm, maybe I should have added a couple more real risks so nobody would thought it was personal....... <grinning> Curtis >>>> Some avid recreational divers who also tech dive claim to be able to >>>> dive recreationally without using computers, but the rest of us are [quoted text clipped - 8 lines] > more real risks so nobody would thought it was personal....... > <grinning> Personal? In rec.scuba??? Tell me you're kidding! LD. ""Magilla"" <cavey_curtis@$$ yahoo.com> http://gue.com/Galleries/Wakulla/042306/index.html Hey, where's the T-shirt? http://gue.com/Galleries/Wakulla/042306/index.html I recognize those tanks! LD. > Be right behind the overweight, smoking, hung-over wrong gas divers in > the bent line....... Hey Curtis, stop picking on me! Frank > Hey Curtis, stop picking on me! Uh, okay....... Curtis >>Hey Curtis, stop picking on me! > > Uh, okay....... > > Curtis you can pick on me - if you choose too if not I have to paint the trim on my house > you can pick on me - if you choose too > > if not I have to paint the trim on my house Naw, be smarter for me to give you my address and let you paint here too. Curtis > > you can pick on me - if you choose too > > > > if not I have to paint the trim on my house > Naw, be smarter for me to give you my address and let you paint here > too. Hello, is this the Sheriff's Office?" "Yes. What can I do for you?" "I'm calling to report 'bout my neighbor Virgil Smith....He's hidin' marijuana inside his firewood! Don't quite know how he gets it inside them logs, but he's hidin' it there." "Thank you very much for the call, sir." The next day, the Sheriff's Deputies descend on Virgil's house. They search the shed where the firewood is kept. Using axes, they bust open every piece of wood, but find no marijuana. They sneer at Virgil and leave. Shortly, the phone rings at Virgil's house. "Hey, Virgil! This here's Floyd....did the Sheriff come?" "Yeah!" "Did they chop your firewood?" "Yep!" "Happy Birthday, buddy!" >> > you can pick on me - if you choose too >> > [quoted text clipped - 31 lines] > >"Happy Birthday, buddy!" that was funny And thus, you enter the eternal archives of alt.humor.best-of-usenet Which can be pretty damned funny at times. Well worth a look. The posts go up in little spurts. Two weeks of nothing and then 12 posts. >> > you can pick on me - if you choose too >> > [quoted text clipped - 32 lines] >"Happy Birthday, buddy!" > Signaturedillon If you can't figure out how to unmunge my address, email me and I'll explain it. > Was working my way through my course work last night and finally figured > out the dive table for repetitive dives, I THINK. but > can anyone explain to me what, on the third table, is the lower number > used for e.g. 25/135. I understand using 25 plus your dive > time to get your new group BUT what do you use the lower number for??? You're going to have to help us to help you on this one. I looked at a couple of tables and didn't find what you're looking at. What table, depth, time and surface intervals are you using? > Also how many people still use the dive table? or do you rely on your > computer? Some do, some don't. Technical divers tend to use tables because few computers are sophisticated enough to handle the kind of diving they do. Not long ago at all, no computers were. Recreational divers tend to use computers because they are sophisticated enough to handle the kind of diving they do, they make multilevel diving easier and because, by crediting time spent at shallower depths, generally allow longer multilevel dives. They generally provide less time for squre profile, single depth, dives. Some technical and some recreational divers use both tables and computers to plan their dives. Those that do, generally use a computer to do the dive. Personally, I think the most important reason to learn to use tables is that they tend to help divers understand decompression issues, something that helps keep them safer whether they're diving based on tables or a computer.. > I was thinking that even if the table says 50 min at your depth it's more > important to watch you SPG?? Right or wrong? Not exactly. It's important to watch both. The 50 minutes at a specific depth is a no decompression time limit. It's the maximum time the producer of the table believes you can stay at that depth before decompression stops are required. Many divers, including me, do not recommend staying at that depth for the maximum time stated. We believe in some buffer. How much buffer is enough buffer is not an easy question to answer. At any rate, if you're not prepared to do required decompression stops, which includes knowning where and how long to do them as well as having sufficient gas, ensuring you're within your no decompression limit is pretty important. Similarly, you won't last long underwater without some kind of gas to breathe, which is what your SPG indicates. Whether you're planning on doing a decompression dive or not, its pretty important to know how much gas you still hve. Newer divers track their available bas by checking their SPG often. More experienced divers, who have a better feel for how deep they are and how long their gas will last at that depth, tend to check less often, but still check occasionally. Lee Lee, If using PADI RDP, You calculate your dive group by depth and time. Then you follow the line to the right to match your surface interval and look down to see your residual nitrogen group. Now you have to turn the table arround to plan your next dive. With your residual nitrogen group and planned next-dives-depth you find a two-coloured box containing two numbers: EDT (Extra Dive Time, to ad to your real dive time on the front of the slate to compensate the nitrogen still in your body) and secondly the corrected max no-deco bottom-time for that depth (also to compensate the nitrogen still in your body). I think the latter is what he is referring to. Frank >> Was working my way through my course work last night and finally figured >> out the dive table for repetitive dives, I THINK. but [quoted text clipped - 47 lines] > > Lee "You're going to have to help us to help you on this one. I looked at a > couple of tables and didn't find what you're looking at. What table, > depth, time and surface intervals are you using?" Sorry Lee, I was going from memory on those numbers. It was 11 pm when I got around to doing my homework and for the life of me could wrap my head around the use for the bottom number. I understand now that the numbeer on the bottom "in blue" means bottom of the water... or max down time. THANKS > Also how many people still use the dive table? or do you really on your > computer? I was thinking that even if the table says 50 min at your depth > it's more important to watch you SPG?? Right or wrong? A few of use never use a computer, using either personalized tables cut from a program or conventional tables. I personally haven't used a dive computer in four to five years, using a standard table with adjustments (deep stops added, END for 32% if used, oxygen deco if used). When I do more longer decos, I'll use a program. Personally I have no use for one, however cannot fault those with the dive understanding to use one as a tool, not a crutch, for those multiple dive days (Lee). Important to watch both gas supply and dive time. Curtis >but can anyone explain to me >what, on the third table, is the lower number used for e.g. 25/135. There is no such thing as THE third table. It would be useful if you mentioned whose table you're using. I use DCIEM tables and don't see what you're describing. Your table itself should tell you what the second number means. It's probably the max dive time at that depth for no-decompression. Check on that, though. Don't dive on a guess. >Also how many people still use the dive table? I use the dive table for planning. It gives me the worst-case numbers and lets me plan an appropriate surface interval. If I actually dive to the max depth, stay there, then ascend, my profile will approximate the tables. If I end up spending some of that time at shallower depths, then I'm likely ahead of the tables and my next dive (per plan) should work easily. SignatureRon (user ron in domain spamblocked.com) > There is no such thing as THE third table. It would be useful > if you mentioned whose table you're using." I'm using the RDP table from PADI, the third table is on the back... I managed to get everything figured out last night. THANKS Hotrod, I expect you to use de PADI Recreational Dive Planner (RDP), where the second number gives you the corrected maximum bottom time. There should be explanation ON the table itself though if it is the RDP. I understand you are informing while doing your homework, but keep asking the next class until you fully understand and then make quite a few examples. Also plan at least your first 30-50 dives and calculate pressure groups, surface interval and residual pressure groups for next dives, before relying on any computer or whatsoever. Computers may malfunction. How would you tell if you had absolutely no idea? Planning a dive is btw ALWAYS necessary, just to make sure you have enough gas to complete your dive, know when to start swimming back to entry instead of a bit further etc. Welcome to the club. Diving is great! Frank (DCM-divers do it deeper, stay in longer and get out wetter. Satisfaction guaranteed) > Was working my way through my course work last night and finally figured > out the dive table for repetitive dives, I THINK. but can anyone explain [quoted text clipped - 7 lines] > > Newbie... >Hotrod, > [quoted text clipped - 19 lines] >(DCM-divers do it deeper, stay in longer and get out wetter. Satisfaction >guaranteed) Thank you for a new .sig. May I use it? >> Was working my way through my course work last night and finally figured >> out the dive table for repetitive dives, I THINK. but can anyone explain [quoted text clipped - 8 lines] >> Newbie... > Signaturedillon If you can't figure out how to unmunge my address, email me and I'll explain it. >Also plan at least your first 30-50 dives and calculate pressure >groups, surface interval and residual pressure groups for next dives, >before >relying on any computer or whatsoever. Computers may malfunction. How would >you tell if you had absolutely no idea? Properly cared for computers don't malfunction often. Humans, on the other hand do. Comparison of information from the tables with information from a computer is not only a good learning experience, it's also a good cross check, at least for the first one or two repetitive dives. Lee > Was working my way through my course work last night and finally figured out > the dive table for repetitive dives, I THINK. but can anyone explain to me > what, on the third table, is the lower number used for e.g. 25/135. I > understand using 25 plus your dive time to get your new group BUT what do > you use the lower number for??? If it's the PADI tables you are looking at and you are talking about the table on the back side with the white and blue numbers, the top number in white is your residual nitrogen time and the lower number is the adjusted no-decompression limit. There should be a key on the back of the table. > Also how many people still use the dive table? or do you really on your > computer? I was thinking that even if the table says 50 min at your depth > it's more important to watch you SPG?? Right or wrong? I mostly use a computer but always keep a set of tables on me as a backup in case the computer fails. Jay http://www.divewithjay.com > Newbie... > Also how many people still use the dive table? or do you really on your > computer? I was thinking that even if the table says 50 min at your depth > it's more important to watch you SPG?? Right or wrong? At least one agency has dropped tables from their curriculum and require dive computers for class. Tables are downright dangerous. People make mistakes with them. They are, by their very complexity, prone to errors. Contrary to popular urban myth, there is nothing to be gained by learning to use dive planners. They are also an extremely inefficient use of your diving resources. The same dive that must be no longer than 10 minutes by RDP can be as long as your air lasts when you have a dive computer. The multi level ascent that may go on for an hour or more (following the deep segment) is a much safer end to the dive. >I was thinking that even if the table says 50 min at your depth it's more important to watch you SPG?? Right or wrong? What? Are you a troll? It's not a matter for rational comparison. If you have a dive computer, there is no benefit or importance to knowing how to use a table dive-planner. If you don't have a dive computer then you better know how to use the dive planner. People who have neither are called "morons". Watching your SPG is not nearly as important as learning to surface before the SPG reads "zero". People who don't do this are called "drowned". "People who don't do this are called "drowned"." OR BENT >"People who don't do this are called "drowned"." OR BENT Nope. Skydiving and scuba diving. It's all fun and games until you suddenly run out of air. When your piston won't move because you don't have enough pressure in the tank to put air in the line, you are seconds away from drowning becuase you also don't have any air in your lungs. If your instructor hasn't already done so, he will, or should, turn your air off in the pool, just so you know what that nonbreath feels like. You can do it, but it's hard to get bent in 30 feet of water on a single Al 80. But you sure can drown. Signaturedillon If you can't figure out how to unmunge my address, email me and I'll explain it. >>"People who don't do this are called "drowned"." OR BENT > [quoted text clipped - 9 lines] >You can do it, but it's hard to get bent in 30 feet of water on a >single Al 80. But you sure can drown. I've heard that a person could stay in less than 30 feet of water for a month before he had to start worrying about getting bent. Assuming he had a constant supply of air, of course. My computer, OTOH, says that isn't so. At least that's what I assume when I look at the desaturation time after shallow dives. I did a 30 minute dive down in LBTS in 17 feet of water and it says that I had a little more than 5 hours before I was desaturated. I had an 80 minute dive in 17 feet of water and the desaturation period was a little over 11 hours. > My computer, OTOH, says that isn't so. At least that's what I assume > when I look at the desaturation time after shallow dives. I did a 30 > minute dive down in LBTS in 17 feet of water and it says that I had a > little more than 5 hours before I was desaturated. I had an 80 minute > dive in 17 feet of water and the desaturation period was a little over > 11 hours. I think that when diving in depths under 30 feet, the computers consider how long it takes for your skin to un-shrivel. > I think that when diving in depths under 30 feet, the computers consider > how long it takes for your skin to un-shrivel. For some reason I started thinking about the Sienfield episode about "Shrinkage", everyone in my office is trying to figure out why I'm laughing.. > My computer, OTOH, says that isn't so. At least that's what I assume > when I look at the desaturation time after shallow dives. I did a 30 > minute dive down in LBTS in 17 feet of water and it says that I had a > little more than 5 hours before I was desaturated. I had an 80 minute > dive in 17 feet of water and the desaturation period was a little over > 11 hours. You might want to check your terms a bit... Saturation means something completely different when you're talking about diving... As far as DEsaturation, I'm not really sure what that would mean other than perhaps an extended decompression after a saturation dive... You're not going to get into a saturation dive situation in just 30 minute... It usually takes about 12 hours at a particular depth in order to be saturated for that particular pressure... >>My computer, OTOH, says that isn't so. At least that's what I assume >>when I look at the desaturation time after shallow dives. I did a 30 [quoted text clipped - 10 lines] > 12 hours at a particular depth in order to be saturated for that particular > pressure... Just talk in terms of "some". As in some in, some out. Gas. Some staying in post dive after a prolonged 10m dive, doesn't mean you get bent. As long a sane ratio between tolerated and actual partial tissue pressure is observed. Matthias >> My computer, OTOH, says that isn't so. At least that's what I assume >> when I look at the desaturation time after shallow dives. I did a 30 [quoted text clipped - 10 lines] >12 hours at a particular depth in order to be saturated for that particular >pressure... I'm using the terms my dive computer software is using: http://yohan.northernlinks.com/diving/Desat.jpg > I've heard that a person could stay in less than 30 feet of water for a > month before he had to start worrying about getting bent. Assuming he had > a constant supply of air, of course. That assumes a critical pressure ratio of around 2:1. Many models assume it is 1.7:1 for nitrogen. Critical pressure ratio represents the amount of pressure reduction that a modeled tissue can be exposed to without the dissolved inert gasses coming out in the form of bubbles. This value is used by the models to determine when a decompression stop is needed, among other things. > My computer, OTOH, says that isn't so. At least that's what I assume when > I look at the desaturation time after shallow dives. I did a 30 minute > dive down in LBTS in 17 feet of water and it says that I had a little more > than 5 hours before I was desaturated. I had an 80 minute dive in 17 feet > of water and the desaturation period was a little over 11 hours. From context, by "desaturation" I think you really mean "reach equilibrium". That has nothing to do with the need for decompression stops. Its just that model's guess at when all of its compartments will have an inert gas pressure close enough to ambient to say equilibrium has been reached. SignatureArt Greenberg artg at eclipse dot net > I've heard that a person could stay in less than 30 feet of water for > a month before he had to start worrying about getting bent. Assuming [quoted text clipped - 6 lines] > dive in 17 feet of water and the desaturation period was a little over > 11 hours. Early decompression theory was based on testing that failed to produce any instances of decompression symptoms at 30 feet. It was concluded that a pressure differential of about two times was acceptable and even desirable. Early decompression procedures are at least partly based on this assumption. It worked just fine for a very long time. To the best of my knowledge, there have still been no verified cases of decompression sickness due to dives to no more than 30 feet that returned to sea level or near sea level pressure. By the time computers came along, things were a bit different. We had methods for testing for the existence and size of bubbles in the blood stream and had discovered that not all body tissues on and offgas at the same rate. Simple formulas gave way to complex ones and simple math gave way to differential equations. We also discovered that, in addition to generating bubbles and bends, errors in decompression methods also generated law suits. Varying levels of fudge factors were added depending on how sure the companies were of their products and how risk averse their insurance companies proved to be. Lee >>>"People who don't do this are called "drowned"." OR BENT >> [quoted text clipped - 20 lines] >dive in 17 feet of water and the desaturation period was a little over >11 hours. "Desaturation" time is different than NDL. "Desaturation" is nothing more than the amount of time it takes for the N2 in your system to reach "normal". Signaturedillon If you can't figure out how to unmunge my address, email me and I'll explain it. > I've heard that a person could stay in less than 30 feet of water for > a month before he had to start worrying about getting bent. Assuming > he had a constant supply of air, of course. > My computer, OTOH, says that isn't so. At least that's what I assume > when I look at the desaturation time after shallow dives. I did a 30 > minute dive down in LBTS in 17 feet of water and it says that I had a > little more than 5 hours before I was desaturated. I had an 80 minute > dive in 17 feet of water and the desaturation period was a little over > 11 hours. Desaturation time has *nothing*, *zero*, *Nada* with how long you can stay at any particular depth. Desaturation time is the length of time required for your body to cook off all the accumulated nitrogen and return PPN2 to 0.79 everywhere in your body. Why you are citing desaturation time as a limitation is a complete mystery. However, your computer will still say that 30 feet is not permitted. You have a computer running Buhlmann ZH L-8ADT. The controlling compartment for a no limit dive is the 635 minute compartment. This algorithm shifts the A/B coefficients according to recent dive history, but for a fresh diver they would be very close to (if not exactly the same) ZHL-16B, in any event, I doubt that any recreational dive would change the a/b coefficients for the longest compartment, except possibly the one we are theorizing (c: Nobody knows for sure since the 8ADT details are proprietary. 635 minute compartment: a= 0.2327 (y-intercept) b= 0.9653 (reciprocal of slope) In Buhlmann forms: Tolerated ambient = (ppia-a)*b where ppia is accumulated inert gas Since we want to surface immediately we want tolerated ambient = 1 (bar), so: 1/b+a= ppia = 1/0.9653+0.2327= 1.26847 = tolerable supersaturation of N2 for immediate surfacing. we're breathing air so, 1.26847/.79= saturating ambient pressure in bar = 1.605882 Which converts to a pressure of 52.30 fsw which is a depth of (52.3-33) = 19.3 feet. According to your *computer* you could surface immediately any dive less than 19 feet. If you'd like to try it, there is a place down in the Keys that has an underwater habitat that you rent like a motel. You dive in and dive out. BTW your computer would report desaturation time on the order 5 *days*, unless you are at some altitude other than sea level. > Desaturation time has *nothing*, *zero*, *Nada* with how long you can > stay at any particular depth. > Desaturation time is the length of time required for your body to cook > off all the accumulated nitrogen and return PPN2 to 0.79 everywhere in > your body. Why you are citing desaturation time as a limitation is a > complete mystery. Because it's the term his dive computer's book uses. Lee >>Desaturation time has *nothing*, *zero*, *Nada* with how long you can >>stay at any particular depth. [quoted text clipped - 7 lines] > > Lee Then his computer's book is wrong. Bullshark is right about desat time. What has not come up in the thread is time to saturation, which is far far longer than allowable time at any depths other than the most shallow. >> Because it's the term his dive computer's book uses. > Then his computer's book is wrong. > Bullshark is right about desat time. I know and, in fact, have told him, as have others. He's already responded, which is how I knew where he went wrong. > What has not come up in the thread is time to saturation, which is far far > longer than allowable time at any depths other than the > most shallow. The thread started with a question about computers versus tables at 30 feet. > >>Desaturation time is the length of time required for your body to cook > >>off all the accumulated nitrogen and return PPN2 to 0.79 everywhere in > >>your body. Why you are citing desaturation time as a limitation is a > >>complete mystery. > > Because it's the term his dive computer's book uses. It's a manual not a book, and it also has page numbers, but they don't qualify as a limitation either. Manuals use many words, simply appearing there is not an excuse or reason for anything. The onus of understanding is on the reader and I don't think that blame should be layed on the publication when the owner fails to comprehend it. > Then his computer's book is wrong. No, it's not. It's Uwatec, and I have 2 or 3 of their manuals laying around and I've read them pretty thoroughly. They accurately use the term, and the computer displays desat time on the screen after diving along with no-fly. Hanson chose to direct to website with a screen shot rather than just pointing to the manual. Check it yourself, it's all accurate. The problem is that he doesn't know what desaturation time means, or he has divined additional meanings for it that don't exist. > What has not come up in the > thread is time to saturation, which is far far longer than The time to saturate the 635 minute compartment would be roughly the same as the time to desaturate it. 12 halftimes (4095/4096 complete) is commonly considered complete saturation, which (as stated earlier) is on the order of 5d7h for the 635 minute compartment. *Real* saturation (as well as desat) is a matter of the frog hopping halfway and takes weeks, but I think I'll let that 1 part in 4096 slide for practical reasons. As I just finished demonstrating mathematically, according to Buhlmann you can stay at 19.3 feet (or less) on air till hell freezes over (complete saturation be damned) and surface immediately. Complete saturation was implied by the OP's post, since he heard he could stay for a month. > Why you are citing desaturation time as a limitation is a complete > mystery. >> > Because it's the term his dive computer's book uses. > It's a manual not a book, and it also has page numbers, but they don't > qualify as a limitation either. Manuals use many words, simply > appearing there is not an excuse or reason for anything. The onus of > understanding is on the reader and I don't think that blame should be > layed on the publication when the owner fails to comprehend it. If you want to be that picky, it's a pamphlet. No matter what it is, you said that the reason he used the term was a complete mystery. I explained it. I didn't condone it. Lee > If you have a dive computer, there is no benefit or importance to > knowing how to use a table dive-planner. If you don't have a dive > computer then you better know how to use the dive planner. People who > have neither are called "morons". When I taught myself how to dive back in the Dark Ages, I didn't have tables, SPG, or a depth gauge originally, but it goes back to the idea of with a single 72 or 80 cu-ft tank, it's pretty damn difficult to get yourself into a deco situation when you're only doing one dive that day... >Was working my way through my course work last night and finally figured out >the dive table for repetitive dives, I THINK. but can anyone explain to me >what, on the third table, is the lower number used for e.g. 25/135. I >understand using 25 plus your dive time to get your new group BUT what do >you use the lower number for??? Have you asked your instructor? You're paying good money for the course. You should be asking him/her. >Also how many people still use the dive table? or do you really on your >computer? I was thinking that even if the table says 50 min at your depth >it's more important to watch you SPG?? Right or wrong? Yes and no. And not really, to your first question, but usually to the second, but do as I say, not as I do. You have to learn and understand the tables to understand how to use a computer properly. And what happens if your computer breaks? Is the rest of you trip trashed, or do you break out the tables and start diving "conservatively"? Or take two computers with you. >Newbie... > Signaturedillon If you can't figure out how to unmunge my address, email me and I'll explain it. |
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