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Stuart Masch sez: > I'm going to try this one more time and then move on to other things. Go ahead and move on, Stuart. If you can't bear the thought of others actually reviewing, discussing, and criticizing the practices that your agency recomends, then perhaps you should simply leave. However, regardless of your presence here or lack thereof, the discussion and criticism will continue. It's up to you about the image you want to present to potential ANDI customers: do you want to continue with the tough-talking anti-discussion image, or do you want to present the head-in-the-sand image, or do you want to present the active participation image? The choice is yours... > I > originally responded to two focused points and I believe they still stand. You clarified ANDI's recomended practices, but you showed no reason why these recomendations are either valid or better than others. > Regarding bailout mixes, Frank pointed out that: > > "ANDI recommends the PO2 of a bailout mix to never exceed 2.0 ata." > > Yes. As in all dive planning, if you plan, expect, or can (reasonably - you > define what it means) find yourself in the types of situations he described, of > course adjust accordingly. They are not requirements. Like the 1.6, 2.0 is an > upper limit. An interesting new twist on the ANDI position. This is not at all discussed in my copy of the ANDI textbook -- in fact, only a broad recomendation for a bailout of 50/50 is given (with the already-mentioned constraint of max ppO2 of 2.0 ata). > There are "limits" in all aspects of life. If they are not appropriate to the > situation, back away from them. . Another new twist from ANDI. When I took the ANDI course, Ed Betts emphasized diving with a ppO2 exposure of 1.6 ata throught the dive -- when I asked "why not use 1.4 to get some conservatism?", he responded that why not just use 1.6 to get all the deco benefits. The total emphasis was on dive planning for the maximum ppO2 to minimize deco obligation. As presented at the class, dive planning was indeed "conducted in a vacuum with blinders on." > "50/50 as a bailout gas has an MOD of 100 fsw". (Thanks, Frank for > independently pointing this out.) *I DID NOT SAY THIS* -- see my other post on this subject. > Don't many > divers sling oxygen bottles (or 80/20) throughout an entire dive just to use for > deco? While it may be a waste of energy to carry it, no one advocates using > that gas as a bottom backup gas. Now you are mixing apples and oranges, so to speak. 1) No, a deco gas is not a backup gas -- you will note that I pointed this out in my post. 2) If you are trained and experienced with the rigging of multiple gas supplies, some of which may be toxic at depth, it is fully acceptable. HOWEVER, the ANDI textbook is not oriented towards this type of diver -- in fact, the ANDI textbook is used in a course which will be a diver's first exposure to alternate gas blends. THEREFORE, it is *COMPLETELY* *INAPPROIATE* to make a broad-base recomendation of a gas mix which has fatal consequences if mis-applied, without going into full detail about regulator marking, placement, etc. > If you want your bailout gas to serve double > duty as a backup gas, of course you must anticipate your ability to perform an > immediate ascent, if it becomes necessary. Should you determine you might not > be able to, then adjust your mix accordingly. Again, interesting new positioning: this is nowhere to be found in either the ANDI text or course, as previously mentioned. > (Remember, our CSU and LSU divers > are no decompression, no overhead environment...) So where would the potential needs of a bailout gas fall, in my previously given taxonomy of bailout needs? And what is the potential benefit of 50/50 over air? (Other than increased profits for ANDI and Island Scuba.) > Stuart Masch, Chief Operating Officer > American Nitrox Divers International -frank -- fhd@in*.ne* | I believe there are 15 747 724 136 275 002 577 605 653 961 181 1 212 559 5534 | 555 468 044 717 914 527 116 709 366 231 425 076 185 631 031 1 917 992 2248 | 296 protons in the universe, and the same number of 1 718 746 7061 | electrons. -- A Eddington, _Philosophy of Physical Science_
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