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You will probably spend a lot more time to get deco mixes, or gas mixes, than these gases will save in terms of decompression, other concerns even let aside. Dives to this depth are done hundredwise a day in the mediterranean, South France. Though, there is a difference, the water is warm there ( 14 centigrade at the bottom), and viz ususually is in between 35 to 10 m. And legislation predicts that only CMAS *** minimum certified divers may enter these depth. Decompresion training and experience at this level is standard. I have experienced quite a few divers who did not respond in a way proper to conduct their obvious tasks at this depth. For you to begin such dive, you should ask yourself some question, I mean, should be able to answer them. How do you get narced? You should be able to calculate /read tables at depth/ read/ understand the gauges, the compass, write completely understandable wetnotes, calculate easy stuff, like air consumption/ time to remain till rule of thirds call for ascent. How do you get along, decowise? George Irvine gave a very true concept, fascinating in its minimalism, about deco. " If I'm not ready to rock after the dive, something is wrong with the decompression scheme" or like that. According to your plan, it will work, but I feel the begin of the deep stops is unnecessary at this depth as well as interfering with the dive reality. You will obviously go down deepest first, after checking the downlines attachment points, memorizing its depth, direction of current, and then follow a gradually upward slope, until you reach a point from which you are sure to reach the ascent line without having to go down again. All this time you will have accounted as bottom time at max depth, using a table ( hopefully not US Navy). So your next deco stop is above the depth at which you join the ascent line. In spite of existing merchandized table , from experience I would use a first stop at 27 m 0.5 min, 21 m 0.5min , 18m 1 min, 15 m 1min, 12m 1min, 9 m 2 min, 6 m 6min, 3m 9-11 min. ascent speed 10m/min. But your milage may vary. The french Marine Nationale 1991 table would give 3min at 6m, 15 min at 3 m, 17m/min a common german Bühlmann/ Hahn table( DECO 1992/2 would give 1 min at 12m 3 min at 9m 6 min at 6m 13 min at 3m, at 10 m /min US Navy 2 min at 6m 7 min at 3m, at 18m/min Comex professional ( 1974): 1 min at 9m 4 min at 6m 13 min at 3m, 15 m/min The old O - 250 m Bühlmann table 3min at 9m 4 min at 6m 9 min at 3 m, 10m/min All assuming air as a breathing gas. Thom Hadfield schrieb: > > Pretty much correct. However to awnser why I donot use other mixes to deco > on. I might. However there will be limited space on the boat with all of the > others divers and I will probably not be aboe to get mixes in the general > area so I was going to try and keep the same % mix for all of my dives that > weekend. with MOD of 140 the entire weekend. > ----- Original Message ----- > From: "Matthias Voss" <mat.voss@t-*.de*> > To: "Manos Manoli" <cytech@ma*.co*.cy*> > Cc: "Thom Hadfield" <thom.hadfield@ho*.co*>; <techdiver@aquanaut.com>; > "Joe" <joe@po*.co*> > Sent: Monday, May 14, 2001 5:31 AM > Subject: Re: Re. Deco diving > > > Manos, > > I interpreted Thom post like that : > > He wants to go to max 140ft, that is 43 m. > > He wants to use a 25/75 O2 / N2 mix, > > and decompress followiing the given scheme, which he says was derived > > from calculating normal air, so to have an extra bit of conservatism. > > > > Thom, is that right ? > > regards > > Matthias -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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