Why do some agencies recommend using a bottom timer instead of a computer

[NatureLVR]

I think there is also a DIR rigidity component to this one. I'm seeing it in another thread on deep air. It seems ratio deco and no deep air (standard gasses) are popular with some DIR practitioners.

It may not apply to all DIR-type people, but I've noticed some of them can be quite rigid in their thinking that the DIR-type way is 100% correct, are militant that any deviation is absolutely wrong, and the dissenting opinion must be strongly re-educated.

Not trying to start a "is DIR good or bad" war, it is just an observation. Let it fly.

 

[boulderjohn]

I guess they did it right during the training. But a couple of years later they did both make a lot of mistakes and both didn’t notice that.

It would be interesting to know that rootcause. Maybe they didn’t dive for a long time.

Maybe other skills are also not good anymore.

If you are doing wrong a gasswitch and you make mistakes and you and your buddy didn’t notice the mistakes, the solution would be training. It doesn’t matter that you do it right 2 years ago during a course.

There are not much divesites here where I can do tech dives. At the end of the month I will do techdiving in Croatia. Tomorrow I will practice skills. I will also check my equipment and tech 1 notes before I arrive in Croatia. Before the project in Croatia will start I will do some diving in Croatia. That would be better than start diving with a lot of taskloading.

You keep missing the point here. The only reason we know they made those mistakes is they got bent and we checed the computer log. If you are not using a computer, you could be making these mistakes on every single dive. You will never know you made those mistakes because you don’t have a computer a long that enables you to check it. If you make mistakes and don’t get bent, you get out of the water thinking you made a perfect dive, totally unaware of the mistakes you made.

 

[boulderjohn]

Not everybody who is using gauge mode is using ratiodeco.

What is better, computer/gauge mode? Can you guarantee that I will not get bent when I’m using a computer instead of gauge mode? If you can guarantee I will stop using gauge mode next dive.

[I used a bottom timer and using VPM for decompression planning for years. I know that.

Your argument would be analogous to this. “I drive drunk, and you drive sober. If you can guarantee me that I cannot have an accident diving sober, then I would do that.”

 

[PfcAJ]

You keep missing the point here. The only reason we know they made those mistakes is they got bent and we checed the computer log. If you are using a computer, you could be making these mistakes on every single dive. You will never know you made those mistakes because you don’t have a computer a long that enables you to check it. If you make mistakes and don’t get bent, you get out of the water thinking you made a perfect dive, totally unaware of the mistakes you made.

You’ll be unaware if you don’t have (and use) adequate training.

 

[boulderjohn]

Keep telling yourself that. It will enable you to maintain that sense of superiority without any need for confirmation.

 

[Dr Simon Mitchell]

I had a discussion on deep stops with Dr. Simon Mitchell who you know is not a fan of Ratio Deco. I asked him how much more safer do you get when you skip the deep stop and add that time to the shallows? He said that the actual safety you create for yourself is so less that "it is not worth talking about."

Hello CSB,

You are misquoting me. I hope this is just clumsy rather than intentional. The exact text I wrote in my PM to you was:

If you did the same decompression time, but distributed your stop time shallower, then you would almost certainly have less risk, The actual difference in risk might be relatively small, and perhaps not worth arguing about. Nevertheless, if people seek the truth on the path to least risk for the same decompression time I very much doubt that RD2 is the answer!

This is a much more cautious interpretation than implied by the black and white terms you are using to describe what I said. We have not accurately measured the actual difference in risk between the approaches one could characterise as "RD2 deep stops vs something shallower", and so my statement is simply a case of scientific honesty. But I very intentionally used the words "might" and "perhaps", and you will note the final phrase in which I state "very much doubt". I would appreciate it if you could try to be more accurate when quoting me in future.

Simon M

 

[PfcAJ]

Keep telling yourself that. It will enable you to maintain that sense of superiority without any need for confirmation.

I have a computer. I’ve had bottom timers that allowed me to check the profile after the dive. I have buddies that keep me honest. I was taught (and use) methods to ensure things are on track.

Sry if you and your guys didn’t get those tools.

 

[boulderjohn]

I love the way the arguments are going here. It seems to me I am reading the following two inthis thread.

1. The math required to do Ratio Deco is not that big a deal. Anyone can do it with ease.
2. The people who make mistakes with Ratio Deco and get bent were not properly trained. A couple years is jot enough.

 

[PfcAJ]

I love the way the arguments are going here. It seems to me I am reading the following two inthis thread.

1. The math required to do Ratio Deco is not that big a deal. Anyone can do it with ease.
2. The people who make mistakes with Ratio Deco and get bent were not properly trained. A couple years is jot enough.

Wel wasn’t part of the “training” that altitude didn’t matter?

Any anyone can do the math with ease. It’s easier than the math in a nitrox class.

 

[CAPTAIN SINBAD]

Hello CSB,

You are misquoting me. I hope this is just clumsy rather than intentional. The exact text I wrote in my PM to you was:

If you did the same decompression time, but distributed your stop time shallower, then you would almost certainly have less risk, The actual difference in risk might be relatively small, and perhaps not worth arguing about. Nevertheless, if people seek the truth on the path to least risk for the same decompression time I very much doubt that RD2 is the answer!

This is a much more cautious interpretation than implied by the black and white terms you are using to describe what I said. We have not accurately measured the actual difference in risk between the approaches one could characterise as "RD2 deep stops vs something shallower", and so my statement is simply a case of scientific honesty. But I very intentionally used the words "might" and "perhaps", and you will note the final phrase in which I state "very much doubt". I would appreciate it if you could try to be more accurate when quoting me in future.

Simon M

Hi Doc! Thanks very much for pointing that out. I was quoting the gist of our conversation here from pure memory and the word "might" was mis-written as "is" so my sincere apologies for that.

I also understand that it is a bit hard to be in your position. I was interviewing a very famous shark researcher once and he said the words, "In the light of what we understand today, Great White sharks may not be as dangerous as we previously believed." This interview was re-purposed by many news agencies around the world. The headline that went on many of the affiliate news networks was, "Great Whites are NOT that dangerous!" says the scientist!" You will notice that this is exactly the same mistake that I made while quoting you but this particular scientist never bothered to come after the networks to have it "fixed." The misquote was totally in line with major public sentiment on sharks so the scientist never bothered.

I will be sure that in the absence of hard scientific evidence, all my future misquotes are in line with popular public sentiment