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Scuba Forum / General / February 200724 Hours Underwater
My 17-year-old came up with the idea of raising money for the local YMCA by spending 24 hours under water. I'd be interested in hearing about anyone with direct experience at this sort of thing. Some things are, of course, apparent. We know his SAC rate, and we can plan the safety divers at 1 CFM to be conservative and add a margin. We are pretty sure we know how to keep him warm, hydrated, and fed. We'll bring dive lights in case of a power outage at night. He'll eat a low- or zero-residue diet for a few days ahead of the event. The LDS is donating the air and loaning us their entire stock of rental tanks. We'll get the pool chlorine to the legal minimum to minimize eye and skin irritation. We've discussed preauthorization for treatment with the local hospital (2 blocks away) and talked about the most probable emergencies (hypothermia, dehydration, barotraumas). He'll breath Nitrox for the last several hours to help stay awake. But--what are we *not* thinking of? What games work well underwater? Any thoughts or information born of experience would be most welcome! John Eells > My 17-year-old came up with the idea of raising money for the local YMCA > by spending 24 hours under water. I'd be interested in hearing about [quoted text clipped - 16 lines] > > John Eells For the sake of Pete, put him in a FFM, preferably with comms. If you guys cant come up with one locally, ping me offline and I'll see what I can do. Anchor something to the bottom of the pool, with enough room for him to comfortably get up into, that will contain air (like 25 gallon or larger) that he can stick his head up into to drink water and eat a granola bar, and set him up with a pee valve. The WKPP guys used to use big cattle watering troughs, but they had the cave ceiling to anchor it to. They would just fill it with gas and stick it to the roof. Several hours on even a mild OEA can really mess with his lungs and respiration. HTH > Several hours on even a mild OEA can really mess with his lungs and > respiration. He'll be in a pool. Why would he be breathing OEA? Lee >>Several hours on even a mild OEA can really mess with his lungs and >>respiration. > > He'll be in a pool. Why would he be breathing OEA? > > Lee The thought is to help keep him alert during the wee hours. I'm told they bleed O2 into casinos at night to keep people from getting tired. But if it's a bad idea we can pursue other avenues. -- John Eells > The thought is to help keep him alert during the wee hours. I'm told they > bleed O2 into casinos at night to keep people from getting tired. But if > it's a bad idea we can pursue other avenues. So provide enriched air at intervals rather than for long periods. There are several computers on the market that allow for gas changes during a dive. All of them monitor CNS and pulmonary oxygen issues. Use one of them. Lee <snip - see below> > For the sake of Pete, put him in a FFM, preferably with comms. If you guys > cant come up with one locally, ping me offline and I'll see what I can do. We're working on borrowing one locally--with surface-to-diver comms, if we get the one we're after. If we can't, I'll be in touch. (But note that we are on the other side of the country from Puget Sound.) I'm mostly concerned about him microsleeping at oh-dark-thirty and inhaling water around the reg. However, I did talk to one person in NH who was involved in a similar effort (done in a tank in a shopping mall), where there were no problems with just using comfortable mouthpieces. > Anchor something to the bottom of the pool, with enough room for him to > comfortably get up into, that will contain air (like 25 gallon or larger) > that he can stick his head up into to drink water and eat a granola bar, and > set him up with a pee valve. There are no anchors available on the pool bottom. Everything will have to be weighted. We're looking at using a garbage can or something similar, but at 62#/CF, it will take a _lot_ of lead to stick it to the bottom with any reasonable amount of air in it. We'll experiment with that in a week or two. > The WKPP guys used to use big cattle watering > troughs, but they had the cave ceiling to anchor it to. They would just fill > it with gas and stick it to the roof. Yeah, I know. I've seen the photos. Not practical in the pool, I'm afraid. > Several hours on even a mild OEA can really mess with his lungs and > respiration. Hmmmm...have to research that. Maybe we'll hold it to a couple of hours. Know where I can find data on this? (I plan to call DAN next week, by the way, and see whether they can help with any of this sort of information.) -- John Eells Original post follows: My 17-year-old came up with the idea of raising money for the local YMCA by spending 24 hours under water. I'd be interested in hearing about anyone with direct experience at this sort of thing. Some things are, of course, apparent. We know his SAC rate, and we can plan the safety divers at 1 CFM to be conservative and add a margin. We are pretty sure we know how to keep him warm, hydrated, and fed. We'll bring dive lights in case of a power outage at night. He'll eat a low- or zero-residue diet for a few days ahead of the event. The LDS is donating the air and loaning us their entire stock of rental tanks. We'll get the pool chlorine to the legal minimum to minimize eye and skin irritation. We've discussed preauthorization for treatment with the local hospital (2 blocks away) and talked about the most probable emergencies (hypothermia, dehydration, barotraumas). He'll breath Nitrox for the last several hours to help stay awake. But--what are we *not* thinking of? What games work well underwater? Any thoughts or information born of experience would be most welcome! > Hmmmm...have to research that. Maybe we'll hold it to a couple of > hours. Know where I can find data on this? (I plan to call DAN next > week, by the way, and see whether they can help with any of this sort of > information.) I know the guy you need to contact. He designs, builds, installs and trains operators on HBO chambers. Ping me offline and I'll hook you up. > <snip - see below> > [quoted text clipped - 12 lines] > effort (done in a tank in a shopping mall), where there were no problems > with just using comfortable mouthpieces. I have slept several hours in the water with only my standard reg. It's no big deal. Generally, you breath wet before it comes out, and wake up. Sleep face down if you can. Weight your ankles so that you do "fin pivots".  Signature“TAANSTAFL” ____________________________________________________________________________ "A prudent man foresees the difficulties ahead and prepares for them; The simpleton goes blindly on and suffers the consequences." - Proverbs 22:3 ____________________________________________________________________________ > But--what are we *not* thinking of? What games work well underwater? Any > thoughts or information born of experience would be most welcome! Poker. Plastic cards and plastic chips. Bring other divers in for a few hands in return for a contribution. We once took part in an underwater monopoly game for charity. All seats rotated in that event. Each player chipped in something for the charity in return for being allowed to play. How about an evening at the underwater movies. Set up a reasonably big screen TV where it can be seen from under the water and use waterproof speakers. I'll bet, if you tried, you'd be able to figure out a way to have popcorn, hot dogs and even soda. Lee > My 17-year-old came up with the idea of raising money for the local YMCA > by spending 24 hours under water. I'd be interested in hearing about [quoted text clipped - 16 lines] > > John Eells Having been a safety diver for this sort of thing several times, I suggest checkers, chess, backgammon (the dice roll strangely underwater), and any playing card game. Coat the cards with many layers of polyurethane before the dive, and soak them in water for several days before the dive. The polyurethane holds the cards together for playing, and soaking them prevents them from floating away scratch the surface of the cards so that water can soak into them. Use soft weights to hold them in place, as they will be only very slightly neutral. Hypothermia is an issue. He cannot dress too warmly, even in a dry suit. Even in a 7 mm with a shorty underneath it, I get cold after about 6 hours. Signature“TAANSTAFL” ____________________________________________________________________________ "A prudent man foresees the difficulties ahead and prepares for them; The simpleton goes blindly on and suffers the consequences." - Proverbs 22:3 ____________________________________________________________________________ >Coat the cards with many layers of polyurethane before the dive . . . Just use plastic ones, or shop around for some that are magnetic. There's a few alternatives that will work. > Hypothermia is an issue. He cannot dress too warmly, even in a dry suit. Yep, and inactivity isn't going to make it any better. I suspect that this will be the most significant limiting factor in the project. A drysuit might help. Providing warm air to the drysuit from a surface supply might help too. Lee > My 17-year-old came up with the idea of raising money for the local YMCA > by spending 24 hours under water. I'd be interested in hearing about [quoted text clipped - 16 lines] > > John Eells My biggest concern would be hypothermia followed by dehydration. Even in "warm" pool water, the body's core temperature will fall. The second concern, dehydration, would come from the body's natural elimination process plus breathing air with virtually no moisture content. I am suspecting he will be relatively shallow but still, that much time underwater breathing compressed air, I have no idea how much if any of a deco obligation he may encounter. I would suggest you run this entire scenario by DAN to discuss your concerns and solicit their input. > My biggest concern would be hypothermia followed by dehydration. Even > in "warm" pool water, the body's core temperature will fall. The second > concern, dehydration, would come from the body's natural elimination > process plus breathing air with virtually no moisture content. As I said in a prior post, we'll have the pool more than warm, and take other measures to prevent hypothermia. We're also going to make sure he pees at least hourly by bringing him fluids--water and Gatorade, at least in CamelBaks--and making sure he drinks enough from them! (Any information about appropriate fluid intake would be great to have.) > I am suspecting he will be relatively shallow but still, that much time > underwater breathing compressed air, I have no idea how much if any of a > deco obligation he may encounter. As I understand it, no deco will be required. The partial pressure of N2 at 10' isn't high enough to cause problems upon surfacing regardless of how long he stays there. Take this with a large grain of salt: If I understand it correctly, the PPN2 has to be above 1.5-2.0 ATM [I forget which] to cause bubble formation. The PPN2 at 10' is 1.022 ATM, and at 8' [a more likely depth, except for his feet, and certainly a more likely average depth] it's .98 ATM. However, I am certainly *not* the world's foremost expert on deco theory. So if anyone has hard info to the contrary, I am of course very interested in having it! > I would suggest you run this entire scenario by DAN to discuss your > concerns and solicit their input. Yep. I plan to do that next week. -- John Eells > Even > in "warm" pool water, the body's core temperature will fall. The second > concern, dehydration, would come from the body's natural elimination > process plus breathing air with virtually no moisture content. He's surrounded by fresh water. He can drink some in a pinch. There's no reason for the core temp to fall if the pool temp is warm enough. It doesn't have to be 98.6, either, due to the body's internal heat generation and insulation. Somewhere around 95 degrees is warm enough to sustain a naked human indefinitely, and that number is obviously lower if he's wearing a wetsuit that helps maintain a warmer layer of water. Of course the potential of raising money might increase if he were naked, and even more if he were a she, but that's beside the point. > I am suspecting he will be relatively shallow but still, that much time > underwater breathing compressed air, I have no idea how much if any of a > deco obligation he may encounter. In a pool? None. There's a hotel that's deeper than that where you can stay overnight. Otherwise, how long of a 10' stop should he do for a 10' max depth? My biggest concern is that it will be obvious he's peeing in the pool at some point. Doesn't anyone care about that? >>Even >>in "warm" pool water, the body's core temperature will fall. The second [quoted text clipped - 10 lines] > were naked, and even more if he were a she, but that's beside the > point. Most pools I have been in are in the upper 80's. The hydration issue was addressed in an earlier message. The plan is for Gatorade and "Camels" (not the smoking kind), to supply hydration. >>I am suspecting he will be relatively shallow but still, that much time >>underwater breathing compressed air, I have no idea how much if any of a [quoted text clipped - 3 lines] > can stay overnight. Otherwise, how long of a 10' stop should he do for > a 10' max depth? The parameters of the dive significantly exceed any profile of recreational diving. I qualified my question not as advice but as a concern (which the OP requested). I suggested he run the entire scenario past DAN, which he said he was going to do. > My biggest concern is that it will be obvious he's peeing in the pool > at some point. Doesn't anyone care about that? If you take the "p" out of the pool, all he is left with is an "ool". > Most pools I have been in are in the upper 80's. And if they can affect the chlorination, I'm sure they have access to the thermostat. In a light suit, the kid should be fine if they crank it up a bit past 90. Putting the kid in a semidry is overkill, and will probably lead to overheating and death. Plus he'll be stewing in his own urine. A nasty way to die. > > In a pool? None. There's a hotel that's deeper than that where you > > can stay overnight. Otherwise, how long of a 10' stop should he do for > > a 10' max depth? > The parameters of the dive significantly exceed any profile of > recreational diving. I qualified my question not as advice but as a > concern (which the OP requested). I suggested he run the entire > scenario past DAN, which he said he was going to do. 135' significantly exceeds any profile of recreational diving. So? Really, is the dive much different than flying in a pressurized aircraft? I've done that for 15 hours at a stretch with not a hint of Gatorade. If he's really worried, he could crawl up to the shallow end before exiting the pool. > > My biggest concern is that it will be obvious he's peeing in the pool > > at some point. Doesn't anyone care about that? If you take the "p" out of the pool, all he is left with is an "ool". Which is "loo" spelled backward. Imagine that. >>Most pools I have been in are in the upper 80's. > [quoted text clipped - 14 lines] > > 135' significantly exceeds any profile of recreational diving. So? I wouldn't say 5 feet significantly exceeds recreational diving. I never rendered an opinion on the entire profile. Merely my concerns that I would want answered by someone far more knowledgeable on the subject than I am. > Really, is the dive much different than flying in a pressurized > aircraft? I've done that for 15 hours at a stretch with not a hint of > Gatorade. If he's really worried, he could crawl up to the shallow > end before exiting the pool. He may be just fine. So did you do the entire 15 hours with no fluid intake? > So did you do the entire 15 hours with no fluid intake? No, I drank the usual fluids: gin & tonic, bloody mary, champagne, red wine. It was business class, so why drink water? But surely your not suggesting the poor kid be given gin & tonic during the dive? >>So did you do the entire 15 hours with no fluid intake? > [quoted text clipped - 3 lines] > But surely your not suggesting the poor kid be given gin & tonic > during the dive? If it were you doing the dive, perhaps. I ran this scenario past our LDS owner who has been diving for 35-40 years and has a lot of technical type training. > I ran this scenario past our LDS owner who has been diving for 35-40 > years and has a lot of technical type training. Yeah, I saw your other post. I know lots of LDS owners who have been diving for many years with lots of technical type training, so that doesn't really impress me. And hearing from yours, I'm still not impressed. (we can die from drinking too much water, so maybe he'll die from sitting in too much water! cough, cough) >>I ran this scenario past our LDS owner who has been diving for 35-40 >>years and has a lot of technical type training. [quoted text clipped - 6 lines] > (we can die from drinking too much water, so maybe he'll die from > sitting in too much water! cough, cough) So what DOES impress you? Someone just jumping in a pool for 24 hours without any type of plan? > So what DOES impress you? Someone just jumping in a pool for 24 hours > without any type of plan? I think the entire enterprise is ridiculous. But if you're going to do something that gives the public a perception of risk, at least take a little risk. Do you think all the high school kids playing football and basketball analyze all the risks that could leave them paralyzed or dead from heart attacks and end up sitting home in fear behind their Playstations, or do they just get on with it and play the game? The kid will be 10 feet deep for a lousy 24 hours with plenty of safety measures already in place, including the ability to get out of the pool whenever he feels like it. I know we live in a nanny state, but some of the precautions I've heard here are simply ridiculous. >>So what DOES impress you? Someone just jumping in a pool for 24 hours >>without any type of plan? [quoted text clipped - 7 lines] > heart attacks and end up sitting home in fear behind their > Playstations, or do they just get on with it and play the game? Considering the relative risks and known risks involved in high school sports vs the unknown risks involved not with just scuba diving, but scuba diving outside the parameters of most training, I think that is a poor comparison. Relativly speaking very few kids suffer permanant injury or death in high school sports. > The kid will be 10 feet deep for a lousy 24 hours with plenty of > safety measures already in place, including the ability to get out of > the pool whenever he feels like it. I know we live in a nanny state, > but some of the precautions I've heard here are simply ridiculous. I think John is correct to examine all of the possiblities. His original post was to get other peoples opinions, concerns. He recognized the fact that this was an out of the ordinary dive profile and that while he is an experienced diver, he sought other opinions. If you think that examining all of the possible contingencies they may encounter is an overly precautious nanny state, remember, we have a young man's life at stake if mistakes are made. Maybe things will go fine and he will make a ton of money for some worthy cause. Maybe something will go wrong and they will bring him out, revive him and he will live to dive another day. Maybe something will go wrong and he will be permanantly injured. Maybe something will go wrong and he will be buried. You don't know. I don't know. John doesn't know. My advice was to seek an expert opinion and I gave the basis for my advice. > Considering the relative risks and known risks involved in high school > sports vs the unknown risks involved not with just scuba diving, but > scuba diving outside the parameters of most training, I think that is a > poor comparison. Relativly speaking very few kids suffer permanant > injury or death in high school sports. Relatively speaking, very few kids suffer permanent injury or death on SCUBA either. High school sports account for 2 million injuries and 30,000 hospitalizations annually. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5538a1.htm Any parent that lets their child participate in high school sports should be criminally liable. > If you think that examining all of the possible contingencies they may > encounter is an overly precautious nanny state, remember, we have a > young man's life at stake if mistakes are made. We send them off to Iraq only a year older, a place where we've made plenty of mistakes. What's the difference? You never know until you try. > Maybe things will go > fine and he will make a ton of money for some worthy cause. Maybe > something will go wrong and they will bring him out, revive him and he > will live to dive another day. Maybe something will go wrong and he > will be permanantly injured. Maybe something will go wrong and he will > be buried. Aren't you the pessimist. > You don't know. I don't know. John doesn't know. My advice was to > seek an expert opinion and I gave the basis for my advice. I do know. I said it was OK. Maybe you could find someone more expert than me, but at least my opinion is free. >>So what DOES impress you? Someone just jumping in a pool for 24 hours >>without any type of plan? [quoted text clipped - 12 lines] > the pool whenever he feels like it. I know we live in a nanny state, > but some of the precautions I've heard here are simply ridiculous. Try staying in 80 degree water for 8 hours, then tell me that the suggestion that hypothermia is an issue. Have you ever done it? I have. And even though you are somewhat better naturally insulated than I am, you will begin shivering as well. Signature“TAANSTAFL” ____________________________________________________________________________ "A prudent man foresees the difficulties ahead and prepares for them; The simpleton goes blindly on and suffers the consequences." - Proverbs 22:3 ____________________________________________________________________________ On Jan 28, 1:41 pm, dazed and confuzzed <dedmann@comcast_remove.net> wrote: > > I know we live in a nanny state, > > but some of the precautions I've heard here are simply ridiculous. > Try staying in 80 degree water for 8 hours, then tell me that the > suggestion that hypothermia is an issue. Have you ever done it? I have. > > And even though you are somewhat better naturally insulated than I am, > you will begin shivering as well. Sure, you'll shiver. Like I said, it's a matter of comfort. Shivering is the body's natural response to cold. It will keep you from becoming hypothermic. But I also suggested they crank the pool up into the low 90s. Easily done with many indoor pools. >Sure, you'll shiver. Like I said, it's a matter of comfort. >Shivering is the body's natural response to cold. It will keep you >from becoming hypothermic. I thought shivering underwater has the opposite affect. It exacerbates the problem. > >Sure, you'll shiver. Like I said, it's a matter of comfort. > >Shivering is the body's natural response to cold. It will keep you > >from becoming hypothermic. > I thought shivering underwater has the opposite affect. It exacerbates the > problem. "In some cases physical exertion in cold water intensifies cooling. But not all cases. Exercise in cold water can generate enough heat to match (Doubt & Smith,1990) or surpass the heat you lose, depending on water temperature in some work, (Toner et al., 1985) and in other work regardless of temperature (McArdle 1984). Arm and leg exercise prevents a fall in core temperature (Craig Dvorak, 1969) benefiting individuals with a low shivering response (Hayward & Keating). Exercise prevents core heat loss particularly in fatter subjects (Pugh, et al., 1960) again demonstrating the benefit of body fat in keeping warm. It is noteworthy that these studies are all of subjects exercising in cold water with no protective garments. Divers wearing exposure suits are more likely to benefit from the heat generation of exercise." http://www.msu.edu/user/manns/Hypothermia.html >> >Sure, you'll shiver. Like I said, it's a matter of comfort. >> >Shivering is the body's natural response to cold. It will keep you [quoted text clipped - 18 lines] > >http://www.msu.edu/user/manns/Hypothermia.html Exercise != Shivering > Exercise != Shivering It's close enough. I found you a cite by a reputable hyperbaric expert that underwater work (exercise, shivering, etc.) may make the diver colder or warmer depending on the diver's body type and the insulation present. Do you have anything that pertains more particularly to underwater shivering other than what you heard somewhere? I couldn't find any reference to this on the net or in my books. >> Exercise != Shivering > [quoted text clipped - 6 lines] >shivering other than what you heard somewhere? I couldn't find any >reference to this on the net or in my books. I believe it is in the PADI open water manual. > >> Exercise != Shivering > [quoted text clipped - 6 lines] > >shivering other than what you heard somewhere? I couldn't find any > >reference to this on the net or in my books.I believe it is in the PADI open water manual. > >Do you have anything that pertains more particularly to underwater > >shivering other than what you heard somewhere? I couldn't find any > >reference to this on the net or in my books. > I believe it is in the PADI open water manual. Can you do more than just believe? I don't have a PADI open water manual. I do have a copy of the PADI Adventures in Diving manual which mentions shivering in connection with hypothermia three times in the book, each time instructing the diver to end the dive upon shivering and mentioning that shivering is something not to be ignored, but nowhere does it say that shivering makes a diver colder. So an exact quote would be appreciated. >> >Do you have anything that pertains more particularly to underwater >> >shivering other than what you heard somewhere? I couldn't find any [quoted text clipped - 10 lines] > >So an exact quote would be appreciated. I don't know where my manual is and I'm not looking for it tonight. I look for it tomorrow as I'm dead tired after driving down and back for the Cheesehead State Meet in Milwaukee this weekend. > It's close enough. I found you a cite by a reputable hyperbaric > expert that underwater work (exercise, shivering, etc.) may make the > diver colder or warmer depending on the diver's body type and the > insulation present. I fail to see how exercising could make the diver colder. Exercise generates heat, not cold. > Do you have anything that pertains more particularly to underwater > shivering other than what you heard somewhere? I couldn't find any > reference to this on the net or in my books. I would assume that shivering is a form of exercise and, that it's likely to be the body's attempt to generate additional heat by exercising the muscles, but I really don't have a good basis for thinking so. Lee > > Do you have anything that pertains more particularly to underwater > > shivering other than what you heard somewhere? I couldn't find any > > reference to this on the net or in my books. > I would assume that shivering is a form of exercise and, that it's likely to > be the body's attempt > to generate additional heat by exercising the muscles, but I really don't > have a good basis for > thinking so. It is, on land at least. JH seems to think that it's not considered exercise underwater, or at least that it doesn't make you warmer underwater. I don't see why there would be a difference. I haven't found anything to back him up. We'll see what his PADI manual says, though I don't know that I'd necessarily trust PADI to get it right. "Shivering is an involuntary, oscillatory muscular activity that augments metabolic heat production. Vigorous shivering increases metabolic heat production up to 600% above basal level. However, a doubling of metabolic heat production is all that can be sustained over long periods." "Shivering can double or even triple oxygen consumption and carbon dioxide production, although the increases are typically much smaller. . . Shivering is rare in elderly [people] because age per se impairs normal thermoregulatory control. . . Likewise, shivering is rarely associated with clinically-important hypoxemia because hypoxia itself inhibits this response " "Seals shiver when exposed to cold air but not when diving in chilly water, a finding that researchers believe allows the diving seal to conserve oxygen and minimize brain damage that could result from long dives. . . . " > It is, on land at least. JH seems to think that it's not considered > exercise underwater, or at least that it doesn't make you warmer [quoted text clipped - 19 lines] > conserve oxygen and minimize brain damage that could result from long > dives. . . . " John is a bit new to some of this stuff and can only comment on what he recalls from external sources. That doesn't make him wrong, but it does sometimes mean his positions are based on less complete information. In this case, I don't question that shivering is a body's attempt to generate additional heat. What I question is comments that it can either warm the diver or cool him. Warm makes sense. Cool doesn't seem to, but that doesn't mean that there's not some basis for the statement. I'm interested in that basis. The only thing I can come up with is that it may further exhaust the diver, something probably related to your information that only a doubling of the metabolic heat production can be sustained. It may refer to the fact that, as the diver become exhausted, his ability to generate heat diminishes, allowing him to become colder, quicker, than would otherwise be the case. This is not quite getting colder due to the shivering itself, but it may be close enough to be the basis for John's statement. Lee > In this case, I don't question that shivering is a body's attempt to > generate additional heat. What I question is comments that it can either [quoted text clipped - 7 lines] > otherwise be the case. This is not quite getting colder due to the shivering > itself, but it may be close enough to be the basis for John's statement. If a diver is motionless in the water, a layer of warm water builds up around the diver, reducing the rate of heat loss, because the difference in temperature between the diver and the water is smaller. When the diver starts shivering, this layer of warm water is broken up and new cold water takes its place. Keeping a layer of warm water next to you is the basis of wetsuits. Richard >> In this case, I don't question that shivering is a body's attempt to >> generate additional heat. What I question is comments that it can either [quoted text clipped - 18 lines] > and new cold water takes its place. Keeping a layer of warm water next > to you is the basis of wetsuits. Assuming the water is motionless as well. On Jan 30, 9:38 am, "Richard Williamson" <richard.williams...@ntlworld.com> wrote: > If a diver is motionless in the water, a layer of warm water builds up > around the diver, reducing the rate of heat loss, because the > difference in temperature between the diver and the water is smaller. > When the diver starts shivering, this layer of warm water is broken up > and new cold water takes its place. Keeping a layer of warm water next > to you is the basis of wetsuits. I thought about that, but I don't imagine there's too much of a temperature gradient of the layers of water between the layer closest to the diver and the layer closest to his suit. Only in the completely motionless diver would these various water layers not intermingle enough to be considered one contiguous layer of water, with the cold water coming in through the suit openings (plus the normal convective heat loss through the suit itself). I doubt that shivering would be enough to disturb the water layer inside the suit enough to exchange with outside water to any greater extent than normal kicking along a reef might do, though it might affect a diver who is otherwise at rest. The question is whether the heat produced by the shivering is less than the heat lost to the environment, and this would depend on the water temperature, suit fit, and suit thickness. >>In this case, I don't question that shivering is a body's attempt to >>generate additional heat. What I question is comments that it can either [quoted text clipped - 11 lines] > around the diver, reducing the rate of heat loss, because the > difference in temperature between the diver and the water is smaller. And smellier, the longer the dive. Matthias <snip> > If a diver is motionless in the water, a layer of warm water builds up > around the diver, reducing the rate of heat loss, because the > difference in temperature between the diver and the water is smaller. > When the diver starts shivering, this layer of warm water is broken up > and new cold water takes its place. Keeping a layer of warm water next > to you is the basis of wetsuits. As I understand it, keeping insulating air trapped in foam neoprene and minimizing water movement in and out of the suit is the basis of wetsuits' insulation. Also, if I recall my physics correctly, even a motionless diver who heats the water will have that water replaced due to convection. -- John Eells > Keeping a layer of warm water next > to you is the basis of wetsuits. Actually, the basis for wetsuits is having something insulating you (i.e. nitrogen encapsulated rubber) from the water temperature... You'll stay warmer with a wetsuit that keeps you drier than one that keeps you wet... If they water is coming in, then your body has to warm it up... It also means that you will probably be flushing that water out with various movements, in essence pumping your body heat into the ocean... Hell, that's why they sell the semi-dry suits... vuc u...LOl.....you like kids??? you molest kids...a.shole! > >>Even > >>in "warm" pool water, the body's core temperature will fall. The second [quoted text clipped - 32 lines] > > If you take the "p" out of the pool, all he is left with is an "ool". "Welcome to our ool. Notice that there is no "P" in it. Please keep it that way." "I don't swim in your toilet. Please don't pee in my pool" Sign seen above a urinal in a restaurant bathroom: "We aim to please. You aim too, please." > My biggest concern would be hypothermia followed by dehydration. Even > in "warm" pool water, the body's core temperature will fall. The second > concern, dehydration, would come from the body's natural elimination > process plus breathing air with virtually no moisture content. Exactly. And the lungs might not like 24 hours at zero humidity, either. > I am suspecting he will be relatively shallow but still, that much time > underwater breathing compressed air, I have no idea how much if any of a > deco obligation he may encounter. Theoretically, none. He should be able to return to 14.7 psi ambient from 22 psi (15 foot pool) with no problem even though saturated in all compartments. But I wouldn't try it myself, and I wouldn't let my kid try it either. > I would suggest you run this entire scenario by DAN to discuss your > concerns and solicit their input. DAN's answer to everything is either "no" or "consult a physician". I don't think they'd be much help. But it has been done before, you should find out if there were any adverse effects. esg On Sat, 27 Jan 2007 16:39:27 +0000, in <3fLuh.15893$yx6.8980@newsread2.news.pas.earthlink.net>, El Stroko Guapo wrote: > Exactly. And the lungs might not like 24 hours at zero humidity, either. Then use a leaky reg... Problem solved... <grin> If he hasn't had much experience with FFMs would be good to get in a few dives and become very familiar with the things. Finding out that the thing doesn't seal nicely wouldn't be as much of a problem if you have a few days to fix the prob (might have to try a couple different models). FFMs are a pain for really long dives because it is harder to drink from a water bag (use the ones with the hoses and mouthvalves, but I've seen gas mask fittings for water sipping that may have been copied by some FFM manufacturers?) . Compressed air is usually very dry so it is important to constantly be sipping something. Gripping a mouthpiece on the other hand is nothing at all for a 1-tank dive, but your jaw may get tired a few hrs in. Microsleep is less of a worry than you think, you wake up very fast ;) I've fallen asleep a couple of times, once laying on my back on the bottom of a fish pen - it probably took me a millionth of a second and I had the reg back in before I even could cough. I think seperating water with your mouth becomes so automatic that dropping the reg isn't a big issue. Would be a lot worse dropping the mask ;) Pool water doesn't have much salt, wonder if there would be problems from long immersion - are there any dermatologists in the group? A drysuit would be best per some of the other comments. Have you guys practiced tank switches? This may be the greatest chance of kerfarglement - maybe have two spare tanks down, in case first tank o-ring goes. He should be heavy for changes so he can't float up (temptation to hold breath during changover is the significant risk?). It's important also to remember that the greatest volumetric increase occurs the last few feet to the surface - so kerfargles that would be minor a little deeper are actually more dangerous close to the top. Thats why I mention tank changes, trying to drink from a FFM, leaky FFM face seals, etc. > My 17-year-old came up with the idea of raising money for the local YMCA > by spending 24 hours under water. I'd be interested in hearing about [quoted text clipped - 16 lines] > > John Eells Thanks. See below. > If he hasn't had much experience with FFMs would be good to get in a > few dives and become very familiar with the things. Finding out that [quoted text clipped - 5 lines] > copied by some FFM manufacturers?) . Compressed air is usually very > dry so it is important to constantly be sipping something. We won't have any control over the FFM schedule but if we get one and can get to try it out beforehand, we will. We're going to use CamelBaks to transport water and fruit juice. They're bags with hoses and bite valves attached that we use for cycling. > Gripping a mouthpiece on the other hand is nothing at all for a 1-tank > dive, but your jaw may get tired a few hrs in. Microsleep is less of a [quoted text clipped - 4 lines] > becomes so automatic that dropping the reg isn't a big issue. Would be > a lot worse dropping the mask ;) Good news on the microsleep front! I am worried about jaw fatigue. If the FFM loan doesn't work out, I'm thinking about getting him a Sea Cure mouthpiece to cut down on fatigue but haven't talked to him about it yet. (I have one and decided I didn't like it that much. Maybe I can remold it for him.) I'm hoping the FFM with comms works out, though, because they there might be an opportunity for one of the radio stations to interview him underwater... > Pool water doesn't have much salt, wonder if there would be problems > from long immersion - are there any dermatologists in the group? A > drysuit would be best per some of the other comments. I swim 50 laps a day (7500') in the same pool. It dries out my skin quite a bit. We'll slather him with something, both on the way in and on the way out. Not sure what yet. Recommendations welcome. Also, I'd love to hear from an opthamalogist. > Have you guys practiced tank switches? This may be the greatest chance > of kerfarglement - maybe have two spare tanks down, in case first tank > o-ring goes. He should be heavy for changes so he can't float up > (temptation to hold breath during changover is the significant risk?). He's quite proficient at doff and don. He was very interested a year or so ago in the skills I was taught in the 70's that they don't teach any more. So I taught him to switch rigs underwater, how to buddy breath without an octo, and one or two other things that I can't recall at the moment. He's only 17 but his dive skills are pretty good. Also, he's comfortable in the water (his SAC rate's .4 CFM). He actually enjoys the doff and don exercise, and practices it when we do pool work at the Y (about once a month during the winter). We have three BCs he can use (four if you count my backplate and wing) and plenty of regs, so we'll just weight them all appropriately and keep at least one assembled and ready to go in advance. Getting into and out of the semi-dry was a lot more complicated, but he managed it underwater on the first try without any bobbles. Next time, we'll bring two weight belts, though, which will make it much easier. We plan to have two safety tanks in the water at all times. At least one will be an AL80 on the pool bottom, reg attached, air on. He will also have an AL20 pony clipped to his harness most of the time. > It's important also to remember that the greatest volumetric increase > occurs the last few feet to the surface - so kerfargles that would be > minor a little deeper are actually more dangerous close to the top. > Thats why I mention tank changes, trying to drink from a FFM, leaky FFM > face seals, etc. He stays firmly on the bottom for doff and don. We'll see what happens with an FFM if we get one. <snip> -- John Eells V-Planner 3.76 by Ross Hemingway, VPM code by Erik C. Baker. Decompression model: VPM - B/E DIVE PLAN Surface interval = 5 day 0 hr 0 min. Elevation = 0ft Conservatism = + 1 Dec to 10ft (0:12) Air 50ft/min descent. Level 10ft 1439:48 (1440:00) Air 0.27 ppO2, 10ft ead Surface (1440:20) Air -30ft/min ascent. OTU's this dive: 0 CNS Total: 0.0% 1313.1 cu ft Air 1313.1 cu ft TOTAL DIVE PLAN COMPLETE ********* WARNING & DISCLAIMER ********* This V-Planner generated dive schedule could indirectly kill you. The author does not warrant that it accurately reflects the Varying Permeability Model algorithms, that it won't get you bent or dead, or that it will produce safe, reliable results. This dive schedule is experimental and you use it at your own risk. Diving in general is fraught with risk, and decompression diving adds significantly more risk. Deep diving utilizing multiple gasses, including Helium, is about as risky as it gets. This schedule is not intended for uneducated users. V-Planner and the decompression schedules it produces are tools for experienced mixed-gas decompression divers ONLY. If you have not been properly trained in mixed-gas decompression diving by an internationally recognized technical certification agency and/or don't have a firm handle on decompression planning and mixed-gas diving, then DO NOT USE THIS DIVE SCHEDULE. > My 17-year-old came up with the idea of raising money for the local YMCA > by spending 24 hours under water. I'd be interested in hearing about [quoted text clipped - 16 lines] > > John Eells With a SAC rate of .4 V-Planner 3.76 by Ross Hemingway, VPM code by Erik C. Baker. Decompression model: VPM - B/E DIVE PLAN Surface interval = 5 day 0 hr 0 min. Elevation = 0ft Conservatism = + 1 Dec to 10ft (0:12) Air 50ft/min descent. Level 10ft 1439:48 (1440:00) Air 0.27 ppO2, 10ft ead Surface (1440:20) Air -30ft/min ascent. OTU's this dive: 0 CNS Total: 0.0% 750.3 cu ft Air 750.3 cu ft TOTAL DIVE PLAN COMPLETE > My 17-year-old came up with the idea of raising money for the local YMCA > by spending 24 hours under water. I'd be interested in hearing about [quoted text clipped - 16 lines] > > John Eells > With a SAC rate of .4 > [quoted text clipped - 19 lines] > > DIVE PLAN COMPLETE <snip> Great program, isn't it? Just for giggles, here's a whole week at 10': ----------------------------------------- V-Planner 3.76 by Ross Hemingway, VPM code by Erik C. Baker. Decompression model: VPM - B DIVE PLAN Surface interval = 5 day 0 hr 0 min. Elevation = 0ft Conservatism = + 2 Dec to 10ft (0) Air 50ft/min descent. Level 10ft 10079:48 (10080) Air 0.27 ppO2, 10ft ead Surface (10080) Air -30ft/min ascent. OTU's this dive: 0 CNS Total: 0.0% 7877.3 cu ft Air 7877.3 cu ft TOTAL DIVE PLAN COMPLETE ------------------------------------------- Still no deco, of course. (But that would be 110 AL80's!) -- John Eells It is a great program but I find it very conservative when compared to my Nitek Duo in the real world. But It'sa great way to estimate gas needs and dive duration and not get screwed in the end! >> With a SAC rate of .4 >> [quoted text clipped - 53 lines] > -- > John Eells Best of luck with it. I hope that all goe's well. Neil. (Australia) > My 17-year-old came up with the idea of raising money for the local YMCA > by spending 24 hours under water. I'd be interested in hearing about [quoted text clipped - 16 lines] > > John Eells > My 17-year-old came up with the idea of raising money for the local YMCA > by spending 24 hours under water. I'd be interested in hearing about > anyone with direct experience at this sort of thing. John, I ran your scenario past the owner of the local dive shop. He has been diving for 35-40 years. Is qualified in many areas of technical diving, (deco, cave, etc ) and holds the highest level of training PADI offers. Here is his reply- "I agree there are some serious hazards. 1. Deco could be a problem. I just don't know. That is extreme exposure and I am aware of two diver that got bent in 26 feet of water after 8 hours of immersion. 2. Dehydration is another area. GatorAde is not a cure all for dehydration. It does replace fluids but does it replace the specifics he will need? He will be leeching out fluids and salts into the water. I don't know what other problems will surface (pun intended) from the long immersion. 3. Hypothermia is more of a problem that most think. You are right to be concerned. He needs not only thermal protection, he needs a way to re-heat. Note a report on hypothermia-- "Death occurs on average from cardiac arrest somewhere below a body core temperature of about 80 degrees Fahrenheit." The whole time he is in the water his body will be trying to equalize with the water temperature. 4. The Full Face is a good idea. Not only for jaw fatigue but for dry mouth. Most importantly, if he went into convulsions he would lose his reg. 5. Remember, a woman just died from drinking too much water. What happens from too much submersion? 6. DEFINATELY call DAN. Then call whatever expert they recommend for more info. 7. He will need to massage his hands and feet as they will be relatively motionless (or at least inactive). It can and has been done. It just depends on how professional they are at in their approach. I agree with your skepticism" > 1. Deco could be a problem. I just don't know. That is extreme > exposure and I am aware of two diver that got bent in 26 feet of water > after 8 hours of immersion. These guys don't seem to have such problems: www.jul.com "Jules' Undersea Lodge is a dream come true for dive enthusiasts who are looking to log a seemingly limitless dive. Guests who complete one of the luxury packages can log 22 hours in one night, and there is no limit to the number of nights they can stay. Even at 21 feet, dive times like these are not covered by the dive tables. Guests actually complete a "saturation" dive, which permits divers to spend extended time underwater as long as proper surfacing intervals are followed. For the shallow water saturation dives of Jules' Undersea Lodge, guests are required to abstain from flying and must adhere to restrictions on further diving for 24 hours after they surface." > 2. Dehydration is another area. GatorAde is not a cure all for > dehydration. It does replace fluids but does it replace the specifics > he will need? He will be leeching out fluids and salts into the water. > I don't know what other problems will surface (pun intended) from the > long immersion. How are you leeching out fluids and salts into the water, except via urination? After all, our skins are pretty water tight. Otherwise I'd be really soggy after even an hour underwater. Hopefully the kid won't be overheated in the semidry so sweating won't be a problem. Lots of moisture will be lost through the lungs as well, but it's only 24 hours. You can survive 24 hours in a desert just fine with sufficient Gatorade. Why should it be different at the bottom of a pool? > 3. Hypothermia is more of a problem that most think. You are right to > be concerned. He needs not only thermal protection, he needs a way to > re-heat. Note a report on hypothermia-- "Death occurs on average from > cardiac arrest somewhere below a body core temperature of about 80 > degrees Fahrenheit." The whole time he is in the water his body will be > trying to equalize with the water temperature. The body's natural metabolic processes and insulation don't require "equalization" with the water temperature until the water drops below 95 and that's for a naked diver. All they need to do is provide a wetsuit that will warm the ambient temperature (whatever they can crank the pool heater to) to 95 inside the suit. Hypothermia survival charts allow for indefinite exposure to water over 80 degrees. Most indoor pools are heated to well over 80 so even without a suit he'd easily survive the 24 hours. Comfort issues would warrant a suit, but the issue is solely about comfort, not about hypothermia. > 4. The Full Face is a good idea. Not only for jaw fatigue but for dry > mouth. Most importantly, if he went into convulsions he would lose his reg. That's what safety divers are for. Besides, why would he be going into convulsions? Did anyone say the kid is epileptic? Get the kid a Seacure and an occasional drink of water. > 5. Remember, a woman just died from drinking too much water. What > happens from too much submersion? This question comes from some who is "qualified in many areas of technical diving, (deco, cave, etc ) and holds the highest level of training PADI offers"??? That's really scary. Does he think we just soak up water and blow up like the Michelin man? Does he really think no one has ever been underwater for 24 hours and lived to tell the tale? Does he really think drinking water is equivalent to sitting in it? > 6. DEFINATELY call DAN. Then call whatever expert they recommend for > more info. Pffthth. > 7. He will need to massage his hands and feet as they will be relatively > motionless (or at least inactive). ? > It can and has been done. It just depends on how professional they are > at in their approach. If they were professional, they wouldn't be doing such a silly stunt. >>1. Deco could be a problem. I just don't know. That is extreme >>exposure and I am aware of two diver that got bent in 26 feet of water >>after 8 hours of immersion. > > These guys don't seem to have such problems: www.jul.com You answered your own issue. > "Jules' Undersea Lodge is a dream come true for dive enthusiasts who > are looking to log a seemingly limitless dive. Guests who complete one [quoted text clipped - 16 lines] > urination? After all, our skins are pretty water tight. Otherwise > I'd be really soggy after even an hour underwater. Last time I saw you get on the boat you were pretty soggy. Nope, the skin is not as "water tight" as you might think. Most of the water you lose from your body, you lose through your skin. > Hopefully the kid won't be overheated in the semidry so sweating won't > be a problem. Lots of moisture will be lost through the lungs as > well, but it's only 24 hours. You can survive 24 hours in a desert > just fine with sufficient Gatorade. Why should it be different at the > bottom of a pool? Maybe he can....maybe he can't. I am not an expert. Never claimed to be. I know enough about it to voice my concern and advise him to get advice from those in the field of study far more knowledgeable than me which is what he is going to do. >>3. Hypothermia is more of a problem that most think. You are right to >>be concerned. He needs not only thermal protection, he needs a way to [quoted text clipped - 20 lines] > into convulsions? Did anyone say the kid is epileptic? Get the kid a > Seacure and an occasional drink of water. Should his body chemistry become to unbalanced, he could lose conciousness and/or convulse. >>5. Remember, a woman just died from drinking too much water. What >>happens from too much submersion? [quoted text clipped - 6 lines] > ever been underwater for 24 hours and lived to tell the tale? Does he > really think drinking water is equivalent to sitting in it? C'mon. Get real. We all know you are not going to soak up water and become like the "Michelin Man". The concern is from whatever may take place in the body after so much time in the water. >>6. DEFINATELY call DAN. Then call whatever expert they recommend for >>more info. [quoted text clipped - 10 lines] > > If they were professional, they wouldn't be doing such a silly stunt. So you recommend just jumping in the pool and swapping out tanks every hour or so and not planning the event at all? > > These guys don't seem to have such problems: www.jul.com > You answered your own issue. > > For the shallow water saturation dives of Jules' Undersea Lodge, > > guests are required to abstain from flying and must adhere to > > restrictions on further diving for 24 hours after they surface." In other words, there are no restrictions except for flying and diving for 24 hours even for divers spending 24 hours or more at 21 feet. The kid shouldn't have any trouble at 10-15 feet, unless he's planning on rocketing to the moon the next day. > > How are you leeching out fluids and salts into the water, except via > > urination? After all, our skins are pretty water tight. Otherwise > > I'd be really soggy after even an hour underwater. > Last time I saw you get on the boat you were pretty soggy. Nope, the > skin is not as "water tight" as you might think. Most of the water you > lose from your body, you lose through your skin. Then we'd be dripping all the time, not just when we sweat or pee. There is some diffusion taking place: "The average loss of water by diffusion through the skin is approximately 300 to 400 ml per day; this amount is lost even in a person who is born without sweat glands," but it's hardly most. Of the 2,300 ml of average intake, there's another 300 to 400 lost through the respiratory tract, some through sweat and feces, and most of it (1,400 ml) lost through urination. Guyton, Textbook of Medical Physiology, p. 383 (1986). Obviously there's less diffusion going on underwater, if any. Your worry seemed to be about diffusion going in the other direction, into the body. I've been browsing my physiology texts trying to find something to counter your worry, without any luck. I guess you'll just have to look at empirical evidence: of the millions of people who swim and bathe every day, do they take on water during their immersions? I suggest weighing yourself before and after a dive to see how much water you're taking on. I doubt it will be too much even when spread out over 24 hours. > > Hopefully the kid won't be overheated in the semidry so sweating won't > > be a problem. Lots of moisture will be lost through the lungs as > > well, but it's only 24 hours. You can survive 24 hours in a desert > > just fine with sufficient Gatorade. Why should it be different at the > > bottom of a pool? > Maybe he can....maybe he can't. I am not an expert. Never claimed to > be. I know enough about it to voice my concern and advise him to get > advice from those in the field of study far more knowledgeable than me > which is what he is going to do. Fine. I'm apparently far more knowledgeable than you, and I said it's OK. I can guarantee that he won't swell up and burst if soaked in water for 24 hours as long as they don't do something stupid like plug up his pores and his urethra. I doubt they were planning on plugging his urethra. > Should his body chemistry become to unbalanced, he could lose > conciousness and/or convulse. Again, that's what safety divers are for. But his body chemistry isn't going to become too unbalanced because he'll be drinking Gatorade. I often mess up my body chemistry worse than that and usually I can remain conscious. > > This question comes from some who is "qualified in many areas of > > technical diving, [quoted text clipped - 3 lines] > > ever been underwater for 24 hours and lived to tell the tale? Does he > > really think drinking water is equivalent to sitting in it? > C'mon. Get real. We all know you are not going to soak up water and > become like the "Michelin Man". The concern is from whatever may take > place in the body after so much time in the water. What might take place, giving birth to a strange alien creature? That only happens in movies. It's only 24 hours. I'd make the kid do a week before I gave any money to his cause. > > If they were professional, they wouldn't be doing such a silly stunt. > So you recommend just jumping in the pool and swapping out tanks every > hour or so and not planning the event at all? The latter: not planning the event at all. While this venture is perfectly safe if they just jump in the pool and swap out tanks every hour or so, it's these stupid "push the body to the limit" feats that often get people hurt. It's ridiculous. If the kid wants to put his life on the line for a good cause, he should go fight terrorists in Iraq (cough) or at least join the Peace Corps. Risk his health for more than a silly stunt. >>>These guys don't seem to have such problems: www.jul.com > [quoted text clipped - 8 lines] > The kid shouldn't have any trouble at 10-15 feet, unless he's planning > on rocketing to the moon the next day. (1) I have never heard of this place but sounds interesting to check out and maybe spend a night. (2) I assume you are breathing compressed air while staying there hince the caveat about flying. This is obviously a climate controlled environment and you are not in constant direct contact with the water until such time as you enter on your own choice. That may very well have answered the question about DCS but I would still run the entire dive plan by DAN. >>>How are you leeching out fluids and salts into the water, except via >>>urination? After all, our skins are pretty water tight. Otherwise [quoted text clipped - 14 lines] > of it (1,400 ml) lost through urination. Guyton, Textbook of Medical > Physiology, p. 383 (1986). What does it say about diffusion through the skin that is in constant contact with water? > Obviously there's less diffusion going on underwater, if any. Your > worry seemed to be about diffusion going in the other direction, into [quoted text clipped - 5 lines] > see how much water you're taking on. I doubt it will be too much even > when spread out over 24 hours. Actually my concern was the opposite. Water that is pulled from the body while diving. Do the people who swim and bathe everyday, do so for 24 hour periods of time? >>>Hopefully the kid won't be overheated in the semidry so sweating won't >>>be a problem. Lots of moisture will be lost through the lungs as [quoted text clipped - 12 lines] > up his pores and his urethra. I doubt they were planning on plugging > his urethra. I certainly hope not. Hey everybody.....Greg says its OK for the kid to dive!!! >>Should his body chemistry become to unbalanced, he could lose >>conciousness and/or convulse. [quoted text clipped - 3 lines] > Gatorade. I often mess up my body chemistry worse than that and > usually I can remain conscious. Usually? >>C'mon. Get real. We all know you are not going to soak up water and >>become like the "Michelin Man". The concern is from whatever may take [quoted text clipped - 5 lines] > It's only 24 hours. I'd make the kid do a week before I gave any > money to his cause. Just don't renew your NRA membership. > Hey everybody.....Greg says its OK for the kid to dive!!! sh.t, what more could they need?. I already hooked them up with a gen-yoo-ine hyperbaric MD, who is also a diver. > That may very well have answered the question about DCS but I would > still run the entire dive plan by DAN. If I were worried, I'd get in touch with someone who knows something about saturation diving. But I'm not worried. There have been controlled studies for this sort of thing, even along the lines of using my gin & tonic technique for rehydration: "In a subsequent study of 34 male sport divers (Eckenhoff & Olstad, 1991), alcohol was administered to half the divers following an extended shallow dive (48 hours at 20 ft). Doppler monitoring for 24 hours after surfacing showed that the level of bubbles in the alcohol group did not differ from the level in the control group." Eckenhoff, R.G., & Olstad, C.S. (1991). Ethanol and venous bubbles after decompression in humans. Undersea Biomedical Research, 18(1), 47-51. So apparently the kid could do twice the dive at twice the depth and still be OK even after getting drunk upon surfacing. See, nothing to worry about. > What does it say about diffusion through the skin that is in constant > contact with water? You think water would be more likely to diffuse out of the body against a gradient of water or against a gradient of air? > Water that is pulled from the > body while diving. > Do the people who swim and bathe everyday, do so for 24 hour periods of > time? Plenty do for hours at a time, so you'd think they'd notice some symptoms of dehydration if the water were getting sucked through their skins. Here's what the Navy has to say: "Causes of Dehydration. Dehydration can occur through excessive perspiration or long periods of breathing dry gases. Immersion in water creates a condition resembling a gravity-free state. The weight of the body and the hydrostatic gradient in the circulatory system are almost exactly counterbalanced by the ambient water pressure. This reduces the volume of pooled blood in the leg veins and results in an increase in central blood volume, leading to an increase in urination (immersion diuresis). The increased urine flow leads to increasing loss of water from the body during the dive." Oh, and thank the Navy for this one. I forgot where I had read it: "A water temperature of approximately 91°F (33°C) is required to keep an unprotected, resting man at a stable temperature." There ya go. That's for the unprotected man. http://www.coralspringsscuba.com/usn/Chap03.pdf <snip> > The latter: not planning the event at all. While this venture is > perfectly safe if they just jump in the pool and swap out tanks every [quoted text clipped - 3 lines] > Iraq (cough) or at least join the Peace Corps. Risk his health for > more than a silly stunt. <one-time rant on> One need not join the Peace Corps. There's plenty to do at home. Most of the time when he risks his health and safety it's because he's a volunteer firefighter. I think that's a reasonably good cause. I'm sure the people whose house his inside team (yeah, he's trained and certified to go into burning buildings) saved this past December 23rd probably think so, too. Anyway, this was, believe it or not, entirely his idea. He'll be 18 in a few months, he's very fit, and he actually does have a clue about what he's getting into. He wants to make a difference for the local Y, which can (trust me) use the help. My role is one of making sure he can do it safely. And frankly I am much more nervous about his firefighting than I am about this. To tell the truth, he does more for his community than most adults I know--and, while there are things that I do, too, he does more than I. That's not something I really want to discourage. <one-time rant off> -- John Eells > Greg Mossman wrote:<snip> > One need not join the Peace Corps. There's plenty to do at home. Most > of the time when he risks his health and safety it's because he's a > volunteer firefighter. I think that's a reasonably good cause. I'm > sure the people whose house his inside team (yeah, he's trained and > certified to go into burning buildings) saved this past December 23rd > probably think so, too. 24 hours at the bottom of a pool is a lot safer than going into a burning building. I'd concentrate your efforts where they're most needed and talk him into a hobby far safer than going into burning buildings, like unprotected sex or recreational drugs. Sitting in a pool doesn't even come close. That's for the rest of us rec.scuba wusses. In fact, I might go sit in my pool now for 24 hours to protest my living conditions, except that it would cost me a fortune to heat it this time of the year (it's not indoors). Will anyone donate to my heating cause? > Anyway, this was, believe it or not, entirely his idea. He'll be 18 in > a few months, he's very fit, and he actually does have a clue about what > he's getting into. He wants to make a difference for the local Y, which > can (trust me) use the help. My role is one of making sure he can do it > safely. And frankly I am much more nervous about his firefighting than > I am about this. There you go. Good for him and for the Y. I used to help out with their annual fund-raising campaign when I was a teen. No risk of DCS, but I would get a hoarse voice trying to maintain my rep as one of the top money-getters for my age group. Today they call it telemarketing, but back then I was proud to call people at dinnertime to get them to donate. (Also, back then, people weren't so quick to hang up and caller-ID didn't exist!) If you got the kid a FFM, maybe you could somehow have him call people at dinnertime from underwater. But they'd probably just hang up. > To tell the truth, he does more for his community than most adults I > know--and, while there are things that I do, too, he does more than I. > That's not something I really want to discourage. That's great. I look back on my childhood community service and wonder when I turned into such a selfish bastard. The last time I did community service was that time when the judge . . . er, never mind. Of course the real reason I ever did any in my youth was to meet girls, but at least the community got something out of it too. Good luck to your son, and I still think the semi-dry is overkill. > In fact, I might go sit in my pool now for 24 hours to > protest my living conditions, except that it would cost me a fortune > to heat it this time of the year (it's not indoors). Will anyone > donate to my heating cause? If I were in the area, I'd be perfectly happy to stop by and pee in the pool for you. It's not much, but every little but helps. :-) Unfortunately, I am not planning on being in the area anytime soon. >> In fact, I might go sit in my pool now for 24 hours to >> protest my living conditions, except that it would cost me a fortune >> to heat it this time of the year (it's not indoors). Will anyone >> donate to my heating cause? > If I were in the area, I'd be perfectly happy to stop by and pee in the > pool for you. It's not > much, but every little but helps. :-) > > Unfortunately, I am not planning on being in the area anytime soon. OK, now we have a new worthwhile reason for a rec scuba get together. We'll all line up to pee in Greg's pool. Tee-shirts Scott? Curtis > We'll all line up to pee in Greg's pool. Tee-shirts Scott? Maybe that will be finally be my excuse to become a gun nut. Peeing in my pool is a capital offense. I'll mow you all down like ducks in a shooting gallery, then throw a few of Grumman's gators in the pool to "clean up". I am the NRA. no NOT A GUN-NUTS...you are a GAY NUTS lol......IS YOUR MAMA BEBE EAT PUGUA? LOL > Maybe that will be finally be my excuse to become a gun nut. Peeing > in my pool is a capital offense. I'll mow you all down like ducks in > a shooting gallery, then throw a few of Grumman's gators in the pool > to "clean up". I am the NRA. That's not the NRA's position, but in this case, I'm on your side. Welcome to the conservative side my son. Lee >>>In fact, I might go sit in my pool now for 24 hours to >>>protest my living conditions, except that it would cost me a fortune [quoted text clipped - 11 lines] > > Curtis The Great Leak of 2007? >> OK, now we have a new worthwhile reason for a rec scuba get together. >> We'll all line up to pee in Greg's pool. Tee-shirts Scott? > The Great Leak of 2007? Greg's ppppppppppppool party. > OK, now we have a new worthwhile reason for a rec scuba get together. |
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