Nitrox and partial pressures

[grantmac]

Sorry, setting up a Teric completely from scratch, even in OC rec mode, requires you read the manual. After doing this countless times now, I could probably do it in my sleep.

Guess I find it much more intuitive.

 

[tursiops]

Let's be realistic here: the 1.4 PPO2 is a conservative setting. Also, my computer did not give me any problems on the first dive with the same gas mixture at the same depth. I was not in danger and I didn't say that I followed the other divers to depth.

Let's be really realistic. As far as you knew, your computer failed. You continued the dive with no trustworthy timing or depth device, and no way to track your N2 exposure. The prudent thing to do would have been to ascend. Otherwise, you are just following the crowd and hoping for the best, which is not a prudent strategy.

 

[tarponchik]

Pray be specific.

You named a computer with an algorithm that most experienced divers consider to be defective and without many of the features of a Shearwater. It has a lower price, but it does not do the same thing.

Or did you mean that for the average OW diver doing relatively shallow dives well within NDLs (like the ones in this case), any cheaper computer will do? If so, then I can see your point.

RGBM is defective? This is news to me. Then why Atomic, Mares, Suunto, and Cressi use it? Did anyone die because he/she used a RGBM-comp rather than a comp based on VPN-B or something?

By "doing the same thing" I meant they keep recreational divers safe. Since the OP was doing just that, I see no point in expanding the discussion to technical diving, if you meant that.

 

[SelfDiver]

Let's be realistic here: the 1.4 PPO2 is a conservative setting. Also, my computer did not give me any problems on the first dive with the same gas mixture at the same depth. I was not in danger and I didn't say that I followed the other divers to depth.

@tursiops is wrong.
The computer is not a necessary part of the dive. Your pre-dive plan was all you need together with a depth+time measurement device.
The computer's function as a Nitrogen and Oxygen calculator has failed mid-dive, but the depth and time are still displayed correctly.
What else do you need?
Live and learn. You will know better next time.
Everyone else can learn from your experience: plan the dive. The computer is a cool tool but that is it.

 

[tursiops]

The computer's function as a Nitrogen and Oxygen calculator has failed mid-dive, but the depth and time are still displayed correctly.

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.

 

[SelfDiver]

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.

You are right, apologies.
He had no plan, not even a bad plan. He was playing chase the computer.
I call that going for a dive accident and failing.

 

[boulderjohn]

RGBM is defective? This is news to me.

You evidently don't keep up with scuba-based social media. "Defective" is too strong a term, but for lots of divers, it is definitely the least preferred. There is an overall feeling that it is too punitive of variations in ascent speed. People feel it demands too long of a surface interval before repetitive dives. It does not automatically adjust for altitude, and its altitude settings are limited. It has other questionable features I won't go into here.

Then why Atomic, Mares, Suunto, and Cressi use it?

That is a really good question. Why indeed would they pay good money for a questionable algorithm when they could have a perfectly good one (Buhlmann) for free? Beats me.

Did anyone die because he/she used a RGBM-comp rather than a comp based on VPN-B or something?

VPN-B is as close to RGBM as you can get, and that one is no longer in favor, either.

As I suggested earlier, though, for really basic dives, it really doesn't make any real difference.

 

[rongoodman]

RGBM is defective? This is news to me.

It might or might not be but you have no way of knowing what the OP’s computer was actually running, just that they licensed the use of the term. It’s not likely that it even has the computational power to run the actual algorithm.