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This whole conversations about half open half close is a waste of time !! I was think it of it an i was laughing during yesterdays dive !! So i made a test ##### 6 seconds to close my fully opened manifold ######. I NEVER remember closing or half closing or any other bu%^&t. Oh !! by the way im living in Europe 2 and i never came up to this half closed half open story before or i dont know anyone even mentioning it before. I got to go diving this morning ....excusemoi !!!! Manos "David E. Smith" wrote: > Mike, > If you read my posts you will see that I have not advocated any of the > options for how to operate your valves. I have stated only that it is not > "common sense" that the valve should be fully open. I have stated that a > valve not fully shut is open (this in response to the statement that a valve > not fully open is shut). I think if you think of the "system response" to > the 2 scenarios (partially shut = open or partially shut = shut) you would > have to agree with my version. In any case, I think these "arguments" have > little to do with the real discussion of whether or not a valve should be > fully open or not. I haven't even really gotten into that. I am simply > commenting on the "absolutist" posts that make statements of common sense or > fact because it suits someone's argument. To this end, what is your source > on the design basis of scuba valves being several turns to shut as an > "intrinsic safety factor". Also, I think you would have to admit, (without > coming to a conclusion on how you should operate your valves) their is a > difference in the likelihood of rolling shut an isolator vice an orifice > valve. If this argument were made to me, I would counter with.."There is > still the likelihood..." But then, that is why we have good technique and > don't contact our manifolds. And when in spite of that technique, we > do...we check. (Not to start another thread, but my isolator knob is > inverted and CAN'T contact the overhead!) > In any case, it may amuse you to discover that I keep my isolator fully > open. I didn't used to. And I arrived at this decision based very little > on any of the arguments posed so far. I just take issue with the fact that > some have arrived at conclusions/statements of FACT, without any proof or > "authority". > > So as I go on and on....Let me state one more time what I CONSIDER to be > fact...whether it is relevant to the main issue or not. > > A partially open valve will act like an open valve. > A partially open valve will be more easily shut (whether intentionally or > not). > I should notice an inadvertently shut isolator by monitoring my SPG. > If I am too stupid to open my isolator before mixing/filling, then that is > Darwin at work. > > Now, there are many more, more relevant facts. These are just the ones > presented (or contradicted) in order to arrive at the decision that the > isolator MUST remain fully open. (Lest you be a farm animal or something. > <g>) So I plead, argue/discuss/whatever the merits...That is why we are all > here (I presume). Let us not dispute fact with opinion and state it as a > fact. > > Happy Diving! > Dave Smith > > dsmith218@ho*.co* > ICQ# 25409809 > > Moderation is for the poor, and the healthy...of which I am neither. - > Polver > > -----Original Message----- > From: Mike Rodriguez [mailto:mikey@ma*.co*] > Sent: Sunday, April 15, 2001 5:43 PM > To: David E. Smith > Cc: Joel Silverstein; RDecker388@ao*.co*; rikard.lundgren@sw*.se*; > techdiver@aquanaut.com > Subject: RE: Isolating Manifold Question > > At 11:11 AM 4/15/2001 -0400, David E. Smith wrote: > > Hello David, > > >If it is not shut, it is open. > > A bump on a fully open valve results in a non-event. The same bump > on a mostly closed valve can result in an accident, maybe a fatal one, > as analysis of several diving deaths over the years related to > inadvertently closed isolators suggests. If it can happen to other > divers, it can happen to any of us, including you. > > -Mike Rodriguez > <mikey@mi*.ne*> > http://www.mikey.net/scuba > Pn(x) = (1/(2^n)n!)[d/dx]^n(x^2 - 1)^n > > -- > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > > -- > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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