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Rich, I do not generally discuss anything about rebreathers with anyone but my team. In this case, you are correct that the machines do not in fact deliver 100%, more like 70-90 depending on the rig , but that is insignificant anyway for the weenie dives these bullshittters are doing, but see the "Baker's Dozon" for all the reasons we carry real oxygen, and it not to blow the piss off of the mig tires. The real story is simple - assholes like Sutton need to build themselves up. The dork has some half-assed Lar 5 rebreather ( a sneak up oxygen rb) , which is nothing more than a bag, a bottle and a mouthpiece which is operated manually. He wants to be a big shot, so talks about it on here instead of on the geek list where they just delete crap that does not contain the words "electronic" or "computer". Here he thinks that the "tekkies" will be impressed by a windbag with a bag of wind. The fact is that while the Lar is a simple rig, who needs any more bullshit on a dive , what kind of idiot would incur enough deco in the ocean to need an oxygen rebreather, and what is being saved here? On our dives, which a stroke like Sutton can not even imagine, where one might think that an oxygen rebreather is necessary or a gas saver or a convenience since we are in a cave entrance and not at sea, and in fact we already are wearing rebreathers so only have to switch to pure oxygen, we rarely bother doing it. In fact, for a five hour bottom time at 300 feet, I use one "Farber" ( as that idiot sutton calls it ) 95 for the whole schmear. I like my oxygen straight up ( see the "Dozen"), as you alluded to, and do not want to be paying attention to a rebreather when I am that far into a dive and tired - why take the risk when the simple way is better anyway? You have to ask yourself, when there is a rebreather list , why do we have to listen to amateur hour over here on techdiver? Keep in mind that this stroke is claiming he is "going to get " a rebreather ( a CCR ), so not only are you dealing with a known bullshitter , a blowhard and a fat slob, you are dealing with a "never ever" with all the answers. Use the delete key on this guy or point out how stupid he is on every post he makes. Rich Lesperance wrote: > > Sending this private, apologies for the unsolicited email. > > I know you're kind of busy deflating this Dave Sutton guy, but was wondering > if you could chime in to the list with your two cents about the thread > that's been going on around the Sutton thing - the possibility of using an > O2 rebreather for deco. > > I had already spoke out tentatively against it, on grounds that you aren't > getting 100%, and decreased reliability. Others answered back pretty much > negating those concerns - citing what seemed to me to be valid counter > points. > > I was curious what you though of it, and others would probably like to hear > it also. I've read the baker's dozen why 80/20 is a stroke mix, but _IF_ a > rebreather could be tweaked to deliver, say, a measurable 95% FO2, what > would you think about that? > > Thanks, > > Rich L > > ----- Original Message ----- > From: William Smithers <will@tr*.co*> > To: Dave Sutton <dsutton@re*.or*> > Cc: Rich Lesperance <richl@uf*.ed*>; <techdiver@aquanaut.com> > Sent: Wednesday, October 27, 1999 11:38 AM > Subject: Re: 02 rebreathers for deco > > > > > Guys, > > > > Using a LAR V for deco has the same issues as using any other > > rebreather for deco. As far as the PO2 goes, when you consider > > water vapor in the loop, and the 1-2% N2 you're not going > > to be able to purge out of the bag (without wasting all your O2), > > you end up with a pretty reliably achievable PO2 at 20ft of between 1.45 > > and 1.55 or so. > > > > Considering the amount of water vapor in the lungs, that's > > not dramatically different from what you get on 100% O2 OC - it's > > just that since you can't easily stick a PO2 monitor in your > > lungs, so the dry OC gas fools you into thinking you're really > > getting a 1.606 PO2 at 20ft. > > > > The reliability vs. OC doesn't really strike me as much > > of a concern. After all, you're only in 20ft of water, > > and it's fairly low-risk to pop up quickly, grab another > > tank, and go back down (SUR-D guys effectively do this on every dive). > > Even if that tank ends up being air, and you have to double > > your 20 and 10 foot stops, the liklihood of a failure is > > low enough that it's not a biggie - for either OC or CC. This > > obviously isn't true if you've just hiked in 2 miles through > > the jungle to go diving somewhere, in which case, take 2 rebreathers > > and save yourself having to haul bottles. > > > > There are two real benefits to doing deco on a(n O2) rebreather. > > First, the hydration issue. Because the loop is closed, > > you're not losing nearly as much expired water. Second, > > the gas is warm, hot even. That adds significant > > thermal padding, right when you want it - on the deco > > line, when you're not generally moving around. > > > > -Will > > > > > > > > On Mon, 25 Oct 1999, Dave Sutton wrote: > > > > > > > > >I disagree. In addition to the gas addition system, you have a > scrubber, > > > >bag, and non-return valves to consider also. In the spirit of > disclosure, > > > >I'll say that _all_ of the failures I have seen (one exception)with > those > > > >components were due to operator error (assembly), or worn equipment > (ie, > > > >dry-rotted bags) that should have been caught during pre-dive checks > > > (again, > > > >operator error). But, we can say the same about most equipment, can't > we? > > > > > > > > > > > > Yup. Which is why we suck-test the rig before diving it. > > > Mine will hold a vacuum for about an hour. Nothing to it. > > > > > > > > > > > > >(The one exception was, I recall, an indeterminate case of CO2 > > > >intoxication - the canister seemed OK, and the diver wasn't really > > > >overexerting himself. We never did figure out what happened). > > > > > > > > > Hmmmmmm. > > > > > > > > > > > > > > > >Failures of only the gas addition system _seemed_ to happen as rarely > as > > > >similarly maintained OC gear > > > > > > Which means zero failures in service, huh?? ;-) > > > > > > > > > > > > > > > > > > > >As for nitrogen off-gassing, decreasing the FO2 during deco, I'd be > > > >interested if someone out there who is math-smart (rules _me_ out) > could > > > >approximate its effect. Is the amount of dissolved N2 in the body so > > > >insignificant, when back in gas phase, as to not really change the FO2 > that > > > >much? Or is it so little that a user should just re-purge every five > > > minutes > > > >or so? Does anyone know the _rate_ of elimination, in units that are > not > > > >simply time expressions? > > > > > > > > > > > > This would be very interesting to me as well. Anybody > > > game to make the calculations? This might just be > > > interesting from an OC viewpoint also. -how much- > > > nitrogen expressed in CC's at 1 ATMA are offgassed > > > after a typical deco dive? > > > > > > > > > Dave Sutton > > > > > > > > > > > > > > > -- > > > 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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