Nitrox and partial pressures

[tarponchik]

The computer was functioning perfectly (it's settings were just wrong); he did not know how to use it. But when he realized something was wrong, why should he assume it is JUST the N2 and O2 that are wrong? After all, pressure sensors fail too, and clocks. You are arguing he had a dive plan. What was his plan? Set the computer and follow it. Bad plan.

Since one can safely stay at 75 ft breathing NITROX-36 for about 100 min, a 2-tank dive of approx 50 min each with a ~1 hr surface interval is guaranteed to be safe and it is quite possible to leave your comp at home for such dives. All you need is a depth gauge and your watch to do the safety stop.

 

[JMarc]

The computer has a setting that resets Nitrox to 50%

No. From the manual citation above the computer switch to a safe but non coherent behavior where it use 50% O2 for MOD warning and 79% N2 for deco computation. I find that surprising, would not expect someone to know about it without referring to the manual and can understand how it could be missed or forgotten even after having read the manual.

RGBM is defective? This is news to me. Then why Atomic, Mares, Suunto, and Cressi use it?

Newer Mares computers have switched to Bülhmann.

 

[tursiops]

All you need is a depth gauge and your watch to do the safety stop.

If he couldn't trust his computer, then he had neither.