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This is a multi-part message in MIME format. ------=_NextPart_000_002E_01C1A9B7.39CC1570 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit list - the following is my reply to a private email I received, but I am removing the identity of the person to whom I am responding in case anyone else would like to read this.... I have also edited slightly and removed any lines from the email which may have been intended to be private or would indicate the person's identity in any way. The original question is still there, below my reply to it. ----------------------------------------------------------------------- When I asked the divemaster if he had an air tank, I was thinking that the Sea Emperor was 80'-85' max depth - I haven't done that dive in a while (I don't like it much) and couldn't remember the max depth for it. When he told me the max depth was 70', I backed off - even though I knew I had gotten over 70' on that dive - what he said at least led me to believe I was wrong about the 80-85' part. I wasn't worried about toxing on the dives at all, but figured I would get about an hour on the first dive and an hour on the second dive. The second dive was supposed to be a 60' reef, but it has been my experience that sometimes that ends up being in the 70's range, too, depending on where I go and where we are dropped. When I analyzed the gas myself, one bottle was 38.4% and one was 38.6% and I tend to assume one percent higher always just to be safe. I have never personally felt any lung damage at all after dives, but I usually don't dive hot mixes either. I wanted a 32 and a 36, but I took two "36" bottles because that was what the dive shop had ready right when I needed them. I thought the dives would be two 60' reef dives - that was the original plan of the captain, but apparently while I was jogging the diver's requested the Sea Emperor for the first dive instead of the 60' reef. The bottles I got were not 36% when I analyzed them, they were 38.4% and 38.6% as I have indicated above. The reason I didn't want to dive 38.4% @ 80-85' for an hour followed by 38.6% @ 70' for an hour was that I didn't want anything interfering with my running schedule so was slightly concerned about the possibility of any lung damage whatsoever. I am not about to expose myself to higher ppO2 for hours at a time with no breaks. My understanding is that 1.4 is the maximum spike ppO2, because the lungs are going to start reacting to the higher partial pressures and building extra layers of cells to protect themselves and also swell and create more mucous to protect themselves, effectively bringing the ppO2 to the body back down anyway and inhibiting gas transfer on the way out. On dives longer than an hour I usually keep it under 1.2, really more like 1.1 at most. I see no reason to expose myself to something like that as there is clearly no "advantage" and it is not necessary anyway. As it turned out I kept my depth right around 60 or less on both dives, except for a brief excursion to 70 on the first dive. The guy struck me really the wrong way because he, without any knowledge whatsoever of the reasoning for my concern nor the slightest clue that I might know fully well how to calculate partial pressures in my head and have been through more math education than he could likely even consider, proceeded to inform me that 38% was safe to breathe at the depth of the Sea Emperor - something I know quite well anyway, whether the actual max depth of the stupid thing is 70' or 85'. His presumptiousness put him immediately on my bad side. Then, when I saw him diving with Karla (whom I didn't realize was Karla from techdiver, but could see was off the idiocy charts by leaps and bounds), the image I had created for him really made sense. Maybe he meant well, but it didn't matter nor even occur to me if this were the case - all I saw was the attitude and his obvious underlying assumption, which was glaringly wrong. This kind of officiousness in a vacuum of any accurate information is not only extremely annoying, it can be outright dangerous. Luckily, I have available to me sources of information far superior to what this guy is working with - but what about the newcomer who does not? peace, --pina ----------------------------- the original message (edited slightly, only to preserve anonymity) -------------------------------------------------------------- Hello Pina- I was wondering about something that happened on the boat Sun. morning. I am curious about your reluctance to dive nitrox on the first dive - 38% to a max depth of 70'-75' ? I believe that GUE uses a max PO2 of 1.4 for all working dives and I agree with this. Am I missing something? When I do the math, 38% at a 1.4 PO2 has a MOD of 88'. And that assuming a max depth of 75' on the Sea Emperor, your max PO2 would have been 1.25. Well below the 1.4 limit. Any info you could provide in your thought process would be helpful. I am always curious to see how others plan their dives. Take care and safe diving. ------=_NextPart_000_002E_01C1A9B7.39CC1570 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=3DContent-Type content=3D"text/html; = charset=3Diso-8859-1"> <META content=3D"MSHTML 6.00.2712.300" name=3DGENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff> <DIV><SPAN class=3D611534521-30012002><FONT face=3DArial = size=3D2>list -=20 </FONT></SPAN></DIV> <DIV><SPAN class=3D611534521-30012002><FONT face=3DArial=20 size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D611534521-30012002><FONT face=3DArial size=3D2>the=20 following is my reply to a private email I received, but I am = removing=20 the identity of the person to whom I am responding in case anyone else = would=20 like to read this.... I have also edited slightly and removed any = lines=20 from the email which may have been intended to be private or would = indicate the=20 person's identity in any way. The original question is still = there, below=20 my reply to it.</FONT></SPAN></DIV> <DIV><SPAN class=3D611534521-30012002><FONT face=3DArial=20 size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D611534521-30012002><FONT face=3DArial=20 size=3D2>----------------------------------------------------------------= -------</FONT></SPAN></DIV> <DIV><SPAN class=3D611534521-30012002><FONT face=3DArial=20 size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D611534521-30012002><FONT face=3DArial size=3D2>When I = asked the=20 divemaster if he had an air tank, I was thinking that the Sea Emperor = was=20 80'-85' max depth - I haven't done that dive in a while (I = don't like=20 it much) and couldn't remember the max depth for it. When he told = me the=20 max depth was 70', I backed off - even though I knew I had gotten over = 70' on=20 that dive - what he said at least led me to believe I was = wrong about=20 the 80-85' part. I wasn't worried about toxing on the dives at = all, but=20 figured I would get about an hour on the first dive and an hour on the = second=20 dive. The second dive was supposed to be a 60' reef, but it has = been my=20 experience that sometimes that ends up being in the 70's range, too, = depending=20 on where I go and where we are dropped. When I analyzed the gas = myself,=20 one bottle was 38.4% and one was 38.6% and I tend to assume one percent = higher=20 always just to be safe. </FONT></SPAN></DIV> <DIV><SPAN class=3D611534521-30012002><FONT face=3DArial=20 size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D611534521-30012002><FONT face=3DArial size=3D2>I have = never=20 personally felt any lung damage at all after dives, but I usually don't = dive hot=20 mixes either. I wanted a 32 and a 36, but I took two "36" bottles = because=20 that was what the dive shop had ready right when I needed = them. =20 I thought the dives would be two 60' reef dives - that was the original = plan of=20 the captain, but apparently while I was jogging the diver's requested = the Sea=20 Emperor for the first dive instead of the 60' reef. The bottles I=20 got were not 36% when I analyzed them, they were 38.4% and 38.6% as = I have=20 indicated above. The reason I didn't want to dive 38.4% @ 80-85' = for an=20 hour followed by 38.6% @ 70' for an hour was that I didn't want anything = interfering with my running schedule so was slightly concerned about=20 the possibility of any lung damage whatsoever. I am=20 not about to expose myself to higher ppO2 for hours at a time with = no=20 breaks. My understanding is that 1.4 is the maximum spike ppO2, = because=20 the lungs are going to start reacting to the higher partial pressures = and=20 building extra layers of cells to protect themselves and = also swell=20 and create more mucous to protect themselves, effectively bringing the = ppO2 to=20 the body back down anyway and inhibiting gas transfer on the way = out. =20 On dives longer than an hour I usually keep it under 1.2, really more = like 1.1=20 at most. I see no reason to expose myself to = something like=20 that as there is clearly no "advantage" and it is not necessary=20 anyway. As it turned out I kept my depth right around 60 or less = on both=20 dives, except for a brief excursion to 70 on the first = dive.</FONT></SPAN></DIV> <DIV><SPAN class=3D611534521-30012002><FONT face=3DArial=20 size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D611534521-30012002><FONT face=3DArial size=3D2>The = guy struck me=20 really the wrong way because he, without any knowledge whatsoever of the = reasoning for my concern nor the slightest clue that I might know fully = well how=20 to calculate partial pressures in my head and have been through = more math=20 education than he could likely even consider, proceeded to = <EM>inform</EM>=20 me that 38% was safe to breathe at the depth of the Sea Emperor - = something I=20 know quite well anyway, whether the actual max depth of the stupid thing = is 70'=20 or 85'. His presumptiousness put him immediately on my bad = side. =20 Then, when I saw him diving with Karla (whom I didn't realize was=20 Karla from techdiver, but could see was off the idiocy charts by = leaps and=20 bounds), the image I had created for him really made = sense. Maybe he=20 meant well, but it didn't matter nor even occur to me if this were the = case -=20 all I saw was the attitude and his obvious underlying assumption, which = was=20 glaringly wrong. This kind of officiousness in a vacuum of any = accurate=20 information is not only extremely annoying, it can be outright = dangerous. Luckily, I have available to me sources of information = far=20 superior to what this guy is working with - but what about the newcomer = who does=20 not?</FONT></SPAN><SPAN class=3D611534521-30012002><FONT face=3DArial=20 size=3D2></FONT></SPAN></DIV> <DIV><SPAN class=3D611534521-30012002><FONT face=3DArial=20 size=3D2></FONT></SPAN> </DIV> <DIV><SPAN class=3D611534521-30012002><FONT face=3DArial size=3D2>peace, = </FONT></SPAN></DIV> <DIV><SPAN class=3D611534521-30012002><FONT face=3DArial=20 size=3D2>--pina</FONT></SPAN></DIV> <DIV><FONT size=3D2><FONT face=3DArial></FONT></FONT> </DIV> <DIV><FONT><SPAN class=3D611534521-30012002><FONT face=3DArial=20 size=3D2>----------------------------- the original message (edited = slightly,=20 only to preserve anonymity)=20 --------------------------------------------------------------</FONT></SP= AN></DIV></FONT> <BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px"> <DIV><FONT face=3DArial size=3D2>Hello Pina-</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>I was wondering about something that = happened on=20 the boat Sun. morning. I am curious about your reluctance to = dive nitrox=20 on the first dive<SPAN class=3D611534521-30012002> - = </SPAN>38% to a=20 max depth of 70'-75'<SPAN class=3D611534521-30012002> = ?</SPAN> =20 </FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>I believe that GUE uses a max PO2 of = 1.4 for all=20 working dives and I agree with this. Am I missing = something? When=20 I do the math, 38% at a 1.4 PO2 has a MOD of 88'. And that = assuming a=20 max depth of 75' on the Sea Emperor, your max PO2 would have been = 1.25. =20 Well below the 1.4 limit.</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>Any info you could provide in your = thought=20 process would be helpful. I am always curious to see how others = plan=20 their dives. Take care and safe diving.</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial = size=3D2></FONT> </DIV></BLOCKQUOTE></BODY></HTML> ------=_NextPart_000_002E_01C1A9B7.39CC1570-- -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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