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--part1_39.19064f8c.28a7377e_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Thom: Prepare yourself for the flames to come. I'm going to be kind. First, if the cost of the manifold concerns you, avoid tech diving. Stop now. It only gets worse from here. Second, since I've never dived this way, I can only parrot others when I say that independent doubles are much more complex to use on a dive. Even so, consider the reasons I have for thinking they are right. 1. You need to keep track of two tank pressures, and switch from one to the other as soon as you reach thirds on it. 2. You have an extra failure point in the second pressure gauge. 3. If a regulator fails, you do not have access to the gas in the cyinder to which it was attached with the ease you have with manifolded doubles. (And yes, you want the ability to isolate too, so go for the manifold with isolator.) 4. In a gas sharing situation, you have to have a different procedure regarding which hose to hand off to the other diver, since you need to know which cylinder has enough gas to share. (Suppose you had breathed one third of tank A, and then one third of tank B, and then turned the dive. You are about to switch to tank A after breathing another third of Tank B on your way out. Which tank do you share with the other diver?) I'm sure others can come up with better reasons and explanations. My advice is don't do it. The only reason I can think of for independents is for sidemount cave diving. That is not a beginner activity. Jan In a message dated 8/11/01 9:05:23 PM Eastern Daylight Time, thom.hadfield@ho*.co* writes: > Being new to tech diving and looking at different gear configurations I have > developed a question? If I go to doubles for deeper and longer dives but do > not use a manifold (cost) what are the major drawbacks? I would assume the > major draw back would be if the right tank and the left reg went bad at the > same time? not being to isoloate one tank off and using a different reg? > Would I assume this would be an acceptible risk while diving with a buddy. > Or are their other reasons that I am just not seeing at the moment. > > > Thom > Visit my web page with underwater and other photos at http://members.aol.com/jsuw3/index.html --part1_39.19064f8c.28a7377e_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: 7bit <HTML><FONT FACE=arial,helvetica><FONT COLOR="#800040" SIZE=2 FAMILY="SCRIPT" FACE="Comic Sans MS" LANG="0">Thom: <BR> <BR>Prepare yourself for the flames to come. I'm going to be kind. <BR> <BR>First, if the cost of the manifold concerns you, avoid tech diving. Stop <BR>now. It only gets worse from here. <BR> <BR>Second, since I've never dived this way, I can only parrot others when I say <BR>that independent doubles are much more complex to use on a dive. Even so, <BR>consider the reasons I have for thinking they are right. <BR> <BR>1. You need to keep track of two tank pressures, and switch from one to the <BR>other as soon as you reach thirds on it. <BR>2. You have an extra failure point in the second pressure gauge. <BR>3. If a regulator fails, you do not have access to the gas in the cyinder to <BR>which it was attached with the ease you have with manifolded doubles. (And <BR>yes, you want the ability to isolate too, so go for the manifold with <BR>isolator.) <BR>4. In a gas sharing situation, you have to have a different procedure <BR>regarding which hose to hand off to the other diver, since you need to know <BR>which cylinder has enough gas to share. (Suppose you had breathed one third <BR>of tank A, and then one third of tank B, and then turned the dive. You are <BR>about to switch to tank A after breathing another third of Tank B on your way <BR>out. Which tank do you share with the other diver?) <BR> <BR>I'm sure others can come up with better reasons and explanations. My advice <BR>is don't do it. The only reason I can think of for independents is for <BR>sidemount cave diving. That is not a beginner activity. <BR> <BR>Jan <BR> <BR>In a message dated 8/11/01 9:05:23 PM Eastern Daylight Time, <BR>thom.hadfield@ho*.co* writes: <BR> <BR></FONT><FONT COLOR="#000000" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0"> <BR><BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Being new to tech diving and looking at different gear configurations I have <BR>developed a question? If I go to doubles for deeper and longer dives but do <BR>not use a manifold (cost) what are the major drawbacks? I would assume the <BR>major draw back would be if the right tank and the left reg went bad at the <BR>same time? not being to isoloate one tank off and using a different reg? <BR>Would I assume this would be an acceptible risk while diving with a buddy. <BR>Or are their other reasons that I am just not seeing at the moment. <BR> <BR> <BR>Thom <BR></BLOCKQUOTE> <BR></FONT><FONT COLOR="#800040" SIZE=2 FAMILY="SCRIPT" FACE="Comic Sans MS" LANG="0"> <BR> <BR><B>Visit my web page with underwater and other photos at <BR>http://members.aol.com/jsuw3/index.html</B></FONT></HTML> --part1_39.19064f8c.28a7377e_boundary-- -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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