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This is a multi-part message in MIME format. ------=_NextPart_000_0008_01C0BCD5.60A29EA0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Same as cave. We do not use "rule of thirds" - that is the old swimming farm animal and singing pig rule. We use stages and save the back gas entirely, or use very little of it. That is simple in a cave: you know how long it takes to go how far at what depth and you take that much gas. We also put in safeties. For wreck, it seems harder but is actually easier: you know how much time you want to spend in the wreck and back and forth distance is not as relative to gas or time, so you simply plan to use that much gas in the stage or stages , which usually means you use most of it before you begin to leave, whereas in a cave you would need as much of it to get out as in. We do not drag stages around with partial gas in them. That is useless. What are you going to do with a bunch of 2/3 full stages in a CF? If we do have a problem, we run stage to stage and jettison them , not carry around a bunch of bottles with tiny amounts of gas in them that will slow us down, and we do not "donate" partial bottles. We dive half plus 200 in cave , the 200 being intended to cover the switching time at depth. If you are just doing a backgas dive, then I would plan on being back on the boat with half my gas, or back at the entrance to the cave with half my gas since in a bad situation, that is likely how much more I would use to get out of it, and in my way of thinking, which clearly separates me from the stroke, if I get the dive completely done on half the gas, then the other half means I can go back and do it again if I have to find somebody, which has happened more than a few times, although none of them were with me in the first pace but with a stroke buddy or no buddy. On the other hand, we see plenty of examples of ocean and cave divers who left dead buddy or dead student or dead other person because they did not think they had enough gas to retrieve them, or mismanaged their gas completely. Gas management has no numbers or rules, it has logic. Let me give you an example. I dive a rebreather for long cave dives. That rebreather is mounted between two 121 cu ft manifolded doubles with normal DIR rig. If my rebreather fails at max pen, while I do have safeties every 1200 feet or so, I have enough gas on my back ( 360 cu ft ), that I can travel 12,000 feet on that supply at 300 feet of depth. If I were on open circuit the whole time, why would I be dumb enough to use my backgas instead of carrying more stages and having that massive get out capability, not to mention that I can use the same doubles over and over and over. -----Original Message----- From: Rich Gulley [mailto:richgulley@us*.ne*] Sent: Wednesday, April 04, 2001 1:09 AM To: techdiver@aquanaut.com Subject: Gas management After reading several posts about carrying additional bottom gas in stage bottles I was left with several questions. I am familiar with carrying stages in caves where you breath down a third and drop the bottle to be picked up on the return trip and the second third breathed down, right? Ok, what would you do in the open ocean? What would proper gas management be for a dive requiring more gas including thirds than you can carry on your back, within reason? Thank you, Rich ------=_NextPart_000_0008_01C0BCD5.60A29EA0 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 content=3D"text/html; charset=3Diso-8859-1" = http-equiv=3DContent-Type> <META content=3D"MSHTML 5.00.2919.6307" name=3DGENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff> <DIV> </DIV> <DIV><FONT color=3D#0000ff face=3DArial size=3D4><SPAN = class=3D910204410-04042001>Same=20 as cave. We do not use "rule of thirds" - that is the old swimming farm = animal=20 and singing pig rule. We use stages and save the back gas entirely, or = use very=20 little of it. That is simple in a cave: you know how long it takes to go = how far=20 at what depth and you take that much gas. We also put in safeties. = For=20 wreck, it seems harder but is actually easier: you know how much time = you want=20 to spend in the wreck and back and forth distance is not as relative to = gas or=20 time, so you simply plan to use that much gas in the stage or stages , = which=20 usually means you use most of it before you begin to leave, whereas in a = cave=20 you would need as much of it to get out as in.</SPAN></FONT></DIV> <DIV><FONT color=3D#0000ff face=3DArial size=3D4><SPAN=20 class=3D910204410-04042001></SPAN></FONT> </DIV> <DIV><FONT color=3D#0000ff face=3DArial size=3D4><SPAN = class=3D910204410-04042001>We do=20 not drag stages around with partial gas in them. That is useless. What = are you=20 going to do with a bunch of 2/3 full stages in a CF? If we do have a = problem, we=20 run stage to stage and jettison them , not carry around a bunch of = bottles with=20 tiny amounts of gas in them that will slow us down, and we do not = "donate"=20 partial bottles. We dive half plus 200 in cave , the 200 being intended = to cover=20 the switching time at depth.</SPAN></FONT></DIV> <DIV><FONT color=3D#0000ff face=3DArial size=3D4><SPAN=20 class=3D910204410-04042001></SPAN></FONT> </DIV> <DIV><FONT color=3D#0000ff face=3DArial size=3D4><SPAN = class=3D910204410-04042001>If you=20 are just doing a backgas dive, then I would plan on being back on the = boat with=20 half my gas, or back at the entrance to the cave with half my gas since = in a bad=20 situation, that is likely how much more I would use to get out of it, = and in my=20 way of thinking, which clearly separates me from the stroke, if = I get the=20 dive completely done on half the gas, then the other half means I can go = back=20 and do it again if I have to find somebody, which has happened more than = a few=20 times, although none of them were with me in the first pace but with a = stroke=20 buddy or no buddy. On the other hand, we see plenty of examples of ocean = and=20 cave divers who left dead buddy or dead student or dead other person = because=20 they did not think they had enough gas to retrieve them, or mismanaged = their gas=20 completely.</SPAN></FONT></DIV> <DIV><FONT color=3D#0000ff face=3DArial size=3D4><SPAN=20 class=3D910204410-04042001></SPAN></FONT> </DIV> <DIV><FONT color=3D#0000ff face=3DArial size=3D4><SPAN = class=3D910204410-04042001>Gas=20 management has no numbers or rules, it has logic. Let me give you an = example. I=20 dive a rebreather for long cave dives. That rebreather is mounted = between two=20 121 cu ft manifolded doubles with normal DIR rig. If my rebreather fails = at max=20 pen, while I do have safeties every 1200 feet or so, I have enough gas = on my=20 back ( 360 cu ft ), that I can travel 12,000 feet on that supply at 300 = feet of=20 depth. If I were on open circuit the whole time, why would I be dumb = enough to=20 use my backgas instead of carrying more stages and having that massive = get out=20 capability, not to mention that I can use the same doubles over and over = and=20 over.</SPAN></FONT></DIV> <DIV><FONT color=3D#0000ff face=3DArial size=3D4><SPAN=20 class=3D910204410-04042001></SPAN></FONT> </DIV> <DIV><FONT color=3D#0000ff face=3DArial size=3D4><SPAN=20 class=3D910204410-04042001></SPAN></FONT> </DIV> <BLOCKQUOTE style=3D"MARGIN-RIGHT: 0px"> <DIV align=3Dleft class=3DOutlookMessageHeader dir=3Dltr><FONT = face=3DTahoma=20 size=3D2><SPAN class=3D910204410-04042001><FONT color=3D#0000ff = face=3DArial=20 size=3D4> </FONT></SPAN></FONT></DIV> <DIV align=3Dleft class=3DOutlookMessageHeader dir=3Dltr><FONT = face=3DTahoma=20 size=3D2><SPAN class=3D910204410-04042001></SPAN></FONT> </DIV> <DIV align=3Dleft class=3DOutlookMessageHeader dir=3Dltr><FONT = face=3DTahoma=20 size=3D2><SPAN class=3D910204410-04042001> </SPAN>-----Original=20 Message-----<BR><B>From:</B> Rich Gulley=20 [mailto:richgulley@us*.ne*]<BR><B>Sent:</B> Wednesday, April 04, = 2001 1:09=20 AM<BR><B>To:</B> techdiver@aquanaut.com<BR><B>Subject:</B> Gas=20 management<BR><BR></DIV></FONT> <DIV><FONT face=3DArial size=3D2>After reading several posts about = carrying=20 additional bottom gas in stage bottles I was left = with several=20 questions. I am familiar with carrying stages in caves where you = breath down a=20 third and drop the bottle to be picked up on the return trip and the = second=20 third breathed down, right? </FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>Ok, what would you do in the open = ocean? What=20 would proper gas management be for a dive requiring more gas including = thirds=20 than you can carry on your back, within reason?</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>Thank you,</FONT></DIV> <DIV><FONT face=3DArial = size=3D2>Rich</FONT></DIV></BLOCKQUOTE></BODY></HTML> ------=_NextPart_000_0008_01C0BCD5.60A29EA0-- -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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