Nitrox course. What's the point?

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If you really need accurate depth measurement, like on a working dive, there are instruments for that.
To what are you referring, laser range-finders?
 
I understand your point.
I agree we must not confuse new divers.
And I give no importance on the name given as "rec" or "tech".
For me the correct concept to give to all new divers is that they should not stop their training after the first OW course. It is not safe to dive with just this low level of knowledge, in the assumption that if one stays within the NDL there is no risk.
Better to get further training and reach the level when you can do safely deco dives.
Only at that point a diver is "complete" and can dive safely, knowing that, when sht happens, he has the resources (knowledge, skills, expertise, equipment, amount of air, etc.) to replan the dive, doing the deco if required.
I understand that this is just my opinion, and some major agencies prefer to sell a number of useless "specialty" certs instead of teaching the discipline and knowledge required for safe deco diving.

I agree with you that any diver would benefit from what we Yanks call "technical training". That was actually one of my first posts in this thread. Even if you never go into deco, it's about the mindset - planning, not just swimming around until the DM tells you to go up.

On the other hand, I wouldn't agree that it's not safe to dive with just OW training. I mean, there is risk in all diving, but the vast majority of certified divers never go beyond OW, and the overall safety record of diving is pretty good. A good OW instructor can certainly give his or her students the skills that they need to be safe divers within their limits.
 
To what are you referring, laser range-finders?

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I agree with you that any diver would benefit from what we Yanks call "technical training". That was actually one of my first posts in this thread. Even if you never go into deco, it's about the mindset - planning, not just swimming around until the DM tells you to go up.

On the other hand, I wouldn't agree that it's not safe to dive with just OW training. I mean, there is risk in all diving, but the vast majority of certified divers never go beyond OW, and the overall safety record of diving is pretty good. A good OW instructor can certainly give his or her students the skills that they need to be safe divers within their limits.

Ok, but let's go back on topic.
Nitrox.
Please tell me what of the two following options is safer:
1) Dive 30 min at 30m with air tables, so you are beyond NDL and you need to make a mandatory deco stop of 3m at 3 meters. Of course you must be deco-trained and deco-equipped.
2) As there is Nitrox-32 in your tank, a 30m/30 min dive is considered within NDL, so an unskilled basic OW diver can do it without any additional precaution.
For me, 1) is safer than 2).
And for you?
 
I did my nitrox course back in 1997. Why? Why not!
Is it useful? Yes and No.
Extend the bottom time? Yes and No as long as you can last the pace. The deciding factor is the amount of gas available.
How often I used it? For a reef dive there is not much point because I can always move up(multi-level) to shallow.
Nowadays I only use it for square profile wreck dive and it is quite rare to find wreck sitting around 25m. Too deep or shallow then I will use Nitrox 21.

It is an option if one is interested.
 
Ok, but let's go back on topic.

You must be new here.

Nitrox.
Please tell me what of the two following options is safer:
1) Dive 30 min at 30m with air tables, so you are beyond NDL and you need to make a mandatory deco stop of 3m at 3 meters. Of course you must be deco-trained and deco-equipped.
2) As there is Nitrox-32 in your tank, a 30m/30 min dive is considered within NDL, so an unskilled basic OW diver can do it without any additional precaution.
For me, 1) is safer than 2).
And for you?

Well, saying which is safer (from a DCS) point of view can be considered in different ways. With #2, no matter what happens, you can ascend directly to the surface, where that is not an option in one. Of course, you said "deco-equipped" which to me means a redundant gas supply if you are doing back gas deco, so I guess you have an option in #1 that you don't have in #2.

And of course, you are asking me to compare decompression stress from two different profiles with two different gasses. It's such an inexact science with so many physiological variables, it's hard to say. But if I had to do this as a back of the envelope calculation, your surfacing GF Hi would be a good way to compare them. If they were the same with #1 and #2, that might mean that they were similar risks. I'm not a decompression expert, so I can't be more accurate than that.
 
Please tell me what of the two following options is safer:
1) Dive 30 min at 30m with air tables, so you are beyond NDL and you need to make a mandatory deco stop of 3m at 3 meters. Of course you must be deco-trained and deco-equipped.
2) As there is Nitrox-32 in your tank, a 30m/30 min dive is considered within NDL, so an unskilled basic OW diver can do it without any additional precaution.
For me, 1) is safer than 2).
As a scientist, you are really only supposed to vary one thing at a time. You seem to be varying two or more.
1) air, air tables, deco trained, deco-equipped, not in NDL
2) nitrox, nitrox tables, unskilled, in NDL
Would you care to simplify it to changing only one variable of interest?

Or is your point just more training and a broader skill set is better. And maybe extra gas and redundant gas.
 
The hope is not blind, hence when the computer is truly, absolutely essential, people have redundancy. People ensure the battery is charged, the firmware is updated, tissue logs are not inadvertently cleared. In the map example, coverage failure doesn't leave you lost, it leaves you exactly where you're standing. If you had the forethought to think about coverage you could've downloaded offline maps..

Risk is a factor of consequence and likelihood, no single method insulates you from both. Computers greatly reduce the likelihood and consequence by tracking your dive with second by second data samples. Analogue instruments are only as good as the frequency they are monitored. Accuracy of the dive profile is less, therefore to control the likelihood of DCS you must increase the conservatism of the dive plan. If the vis is great and the wreck is good and the gas is going well, I can add 5min of bottom time, or spend a bit longer in the bottom decks, without any increase in risk. With analogue gear that is not wise, I really must stick to the plan and hope everything holds for the next dive.

To be clear, I'm not suggesting any reason for you to change. I will suggest your reasons listed to not change are inaccurate but that has no bearing on your current methods.
Nice clarity - good post
 
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