Place of dive tables in modern diving (Split from the basic thread)

[stuartv]

Sure! I mean, in a classroom setting it definitely makes complete sense to use a visual representation that depicts what's going on theoretically. A planning software can be a very fine choice, I think.
In terms of the training applications, the reason I like RD/Min Deco is because of the in-water use. There, however, it makes sense to not have any "assistance", for full utility.

What is it you're trying to teach?

If you're trying to teach an understanding of "deco" (to put it simply), why not use the better tool (i.e. the one with an interactive visual component)?

If you're trying to teach how to predict/sanity check an ascent, again, why not use the better tool (i.e. the one with an interactive visual component)?

If you're trying to teach how to get out of the water safely, why not teach how to understand and follow a computer (after you've taught how to predict/sanity check an ascent)? Surely it is easier to follow a computer than do arithmetic while potentially multi-tasking AND potentially affected by some degree of narcosis?

Now just hold on for a second there;
I'm saying I think computers and min deco are better options than RDP, and why.
It's easy to just say that's preaching, but I'm approaching the RDP-question in a fair fashion here.

If you don't agree with the points I make on the topic at hand, of course it's fair to make a counterargument, but it's not fair to start shoehorning me into the role of some preacher when I'm saying I don't think the RDP is a strong option, and clearly argue why.

If sure sounds like preaching when you won't answer this question:

So, back to my questions.

Who invented Min Deco?
What scientific studies were conducted to determine it is a superior system?

The term preaching (to me) implies some degree of a request for endowment of faith on the part of the listener. That seems to be what you're asking for.

The DSAT tables don't seem to be asking me to "have faith". The DSAT tables are simply a distillation of actual research and the actual data that the summary (the tables) is based on is available for me to look at, if I want to eschew faith and draw my own conclusions instead.

 

[Dan_P]

You'll need to back further away than that. You have innumerable posts preaching for Min Deco.

I think min deco a better solution than RDP, and I think so is a computer.
Both work.
That pretty much sums it up.

I've spoken about why. And honestly, I think that's fair enough.

I'm not talking crap about computers here or telling anyone what they have to use.
I'm saying I think RDP isn't a strong option, and heck, who here is even disagreeing with that?

But really, if you take a step back from this, don't you think this is packed with some deal of intolerance towards the concept of min deco because of a conception that it has to be an algorithm in the same fashion that RGBM, VPM, GF30/80 are algortihms?
It's part of a framework - the utility of it in terms of easy planning/adaptation is part of the weighting, unlike an algortihm.
It's scalable into Ratio Deco, which is a factor that matters.

Things like that often/sometimes/probably/possibly come at the expense of approximation to "perfection" (whatever that may be) in terms of decompression, and that's okay to someone who opts to use such a framing system. There is some leeway, sure, but I embrace that it'll not be absolutely perfect. That's okay.

Now, I could start talking about deep stop theory, Pyle Stops, or whatever - but the fact of the matter is that Ratio Deco is likely not the optimal way to ascend in terms purely decompression. And it's not exactly written in stone either.
But I choose to employ it anyway because it has other benefits, which I think matter, too.
(How do you gauge that? By which metric?)

That's on me. But that's a wildly different statement than if I were stating RD/Min Deco is definitely a magic algorithm that blows everything else out of the water because, well, because.

But my point is I think RDP is a worse option than both min deco and computers, by a number of parametres that I listed previously. That's literally all I'm getting to.

What is it you're trying to teach?

Situational awareness

 

[boulderjohn]

But really, if you take a step back from this, don't you think this is packed with a some deal of intolerance towards the concept of min deco because of a conception that it has to be an algorithm in the same fashion that RGBM, VPM, GF30/80 are algortihms?
It's part of a framework - the utility of it in terms of easy planning/adaptation is part of the weighting, unlike an algortihm.
It's scalable into Ratio Deco, which is a factor that matters.

The intolerance toward min deco and the UTD version of ratio deco is that neither one is based upon scientific evidence. The fact that Min Deco is scalable into Ratio Deco is not a compelling argument to people who have no interest in using UTD's ratio Deco.

 

[Dan_P]

The intolerance toward min deco and the UTD version of ratio deco is that neither one is based upon scientific evidence. The fact that Min Deco is scalable into Ratio Deco is not a compelling argument to people who have no interest in using UTD's ratio Deco.

John. I'm not trying to compel anyone.
I've even said that I acknowledge RD is probably not perfect in terms purely decompression.

You're using a reference that isn't comparative. Fine.
You show that RDP and 18m per minute is, well, safe enough. Fine.
That's it. And I'm not disagreeing.
But you can't use that to bash UTD (again, again).

I was talking about the RDP, and you asked me about min deco. I've answered that my reason for using min deco dwells partially outside of purely decompression matters (the physiological process).
Your answer is that you don't like it and that I now have to prove to you that it's better inside purely decompression matters (the physiological process).

Seriously, we were having a discussion on the merits (or lack thereof) of the RDP. And you were not even disagreeing.

 

[tursiops]

The Rule of 120, Fibonacci curves, Ratio Deco, MinDeco, are all curve fits -- some better than others -- to the raw curves provided by the basic algorithms, which are derived from testing and then calcuated by dive computers and put into table form by things like the RDP. The curve fits can never be any better than the original they are designed to mimic, but of course they might be easier to use. They'd better be easier to use, otherwise they add no value. I'll put the Rule of 120 against Min Deco any time for ease of use! But, is ease of use the criteria? In the end, of course, nothing is really easier to use than glancing down at your wrist. Much of this discussion has been about how best to teach the basic concepts, not ease of use.

 

[scubadada]

John. I'm not trying to compel anyone.
I've even said that I acknowledge RD is probably not perfect in terms purely decompression.

You're using a reference that isn't comparative. Fine.
You show that RDP and 18m per minute is, well, safe enough. Fine.
That's it. And I'm not disagreeing.
But you can't use that to bash UTD (again, again).

I was talking about the RDP, and you asked me about min deco. I've answered that my reason for using min deco dwells partially outside of purely decompression matters (the physiological process).
Your answer is that you don't like it and that I now have to prove to you that it's better inside purely decompression matters (the physiological process).

Seriously, we were having a discussion on the merits (or lack thereof) of the RDP. And you were not even disagreeing.

You really do sound like an evangelist.

 

[scubadada]

The Rule of 120, Fibonacci curves, Ratio Deco, MinDeco, are all curve fits -- some better than others -- to the raw curves provided by the basic algorithms, which are derived from testing and then calcuated by dive computers and put into table form by things like the RDP. The curve fits can never be any better than the original they are designed to mimic, but of course they might be easier to use. They'd better be easier to use, otherwise they add no value. I'll put the Rule of 120 against Min Deco any time for ease of use! But, is ease of use the criteria? In the end, of course, nothing is really easier to use than glancing down at your wrist. Much of this discussion has been about how best to teach the basic concepts, not ease of use.

The adapted rule of 120 works pretty well as a conservative estimate for any algorithm. I use the DSAT rule of 110 for air, 127 for 32% and 135 for 36%. Since I dive 2 computers, I really never need to go to my XXX rule, but could.

 

[Dan_P]

You really do sound like an evangelist.

I just have a tag on me saying UTD and all of the sudden I'm that guy.
Meet me in real life and tell me I sound like an evangelist - I have a cockney dialect and swear like a sailor.
The notion is quite ridiculous

But, is ease of use the criteria? In the end, of course, nothing is really easier to use than glancing down at your wrist.

I've chosen to put it up as one of the criteria. And I agree that computer is the easiest to use.

 

[dmaziuk]

That's right. As long as you are within the limits of a pressure group, that option is not open to you.

Sorry, I am obtuse like that. Table 3 and it tells me that in initial state A I may go to 5 atm for 7 minutes ABT with 2 minutes penalty time RNT and they should be added to the TBT. 7 + 2 = 9 so I expect table 1 to show me 9 minutes of TBT at 5 atm for the state A.

What I see is a down-arrow. The number down in B row is 5. That's TBT, right? The one that was suppose to be 9? Am I correct in seeing a 5 there?

Did they also redefine plus to mean minus: 7 - 2 = 5, like they redefined "no stop" to mean stop is required in the grey area? Or does table 3 refer to the numbers for initial state "no letter" when it says "A"?

Tables are hard for me -- I'm sure other students see them differently. What would be easy for me is if I saw initial state S0, from which you go to depth Pi for time Tj and end up in state SX. From SX you go to depth Pm for time Tn to land in SY. For every i,j there is m,n such that that it takes you back to S0. The look-ahead table 3 gives you the same X'es and i's as the main table, and "no stop" means stop is not required. Simple and stupid, that's what I like.

 

[tursiops]

Sorry, I am obtuse like that. Table 3 and it tells me that in initial state A I may go to 5 atm for 7 minutes ABT with 2 minutes penalty time RNT and they should be added to the TBT. 7 + 2 = 9 so I expect table 1 to show me 9 minutes of TBT at 5 atm for the state A.

What I see is a down-arrow. The number down in B row is 5. That's TBT, right? The one that was suppose to be 9? Am I correct in seeing a 5 there?

Did they also redefine plus to mean minus: 7 - 2 = 5, like they redefined "no stop" to mean stop is required in the grey area? Or does table 3 refer to the numbers for initial state "no letter" when it says "A"?

Tables are hard for me -- I'm sure other students see them differently. What would be easy for me is if I saw initial state S0, from which you go to depth Pi for time Tj and end up in state SX. From SX you go to depth Pm for time Tn to land in SY. For every i,j there is m,n such that that it takes you back to S0. The look-ahead table 3 gives you the same X'es and i's as the main table, and "no stop" means stop is not required. Simple and stupid, that's what I like.

Don't use Table 3, it seems to be confusing you.
Use Table 1, get 9 minutes for your first dive to 40m, which puts you in PG "G". Follow "G" across to the last column on the right: it says that you are in PG "A" if your SI is between 1:42 and 4:42. For longer SIs, you are no longer in PG "A", you are starting fresh. You are NOT "A". "A" is not your "initial state; it is a state that still has some residual nitrogen in you.
I sincerely hope you use a computer.