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Sheck’s dive plan for his 1989 dive to 881ftNacimiento del Rio Mante in MexicoAnalysis and graphs generated by the CDM18 Dive Profile Analyser
Sheck's 'Dr-X' Dive Plan(converted from feet to meters. Analysis and graphs from the CDM18 Dive Profile Analyser)
Sheck's Isobaric Counter-diffusion Avoidance technique.Or... See how a very clever man avoided in an in water DCS hit by gradual gas switching. Notes from CDM Analysis results:- 1. The dive profile is not bad at all, even by modern analysis standards 2. Two ICD events are predicted at 89 and 72 meters <EXTRACT 'CAVERNS MEASURELESS TO MAN' Author:- SHECK EXLEY page 259> "At 260 feet and 250 feet... (80meters) I counted sixty-second stops with my fingers, then ad- dressed a new source of concern: Jochen and Gene's mysteri- ous vestibular hit. At 240 feet I had to switch from breathing 50 percent helium and 40 percent nitrogen to air, which contains 79 percent nitrogen. According to their informa- tion, the abrupt increase in nitrogen could result in instant death. And all authorities predicted a sudden onset of severe narcosis. To make the switch as gradual as possible, I took only a single breath of air from the tank we had earlier left at 240 feet, then switched back to the helium mix for two breaths. Then came two air breaths, then back to the deep mix for one inhalation. Finally I switched over to air completely, bracing myself for the severe narcosis and dreaded vestibular hit, all the while doing my best to count off the seconds required for the stop. Nothing happened, no narcosis, no sudden lapse into unconsciousness. The only thing I felt was warmer, thanks to not having to breathe helium any more. Apparently my strategy of keeping a maximum amount of nitrogen in the deep mix worked." <EXTRACT ENDS>
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