Slow tissue on gas from stops

[Dan_P]

@Patoux01
Nope, if your depth is 50m and your avg. depth is just under 48m, you'd use 48m.

 

[Patoux01]

Ah okay, it didn't seem clear to me as it was written previously.

 

[Jack Hammer]

@Jack Hammer It accounts for a difference in avg. bottom times for sure - but it doesn't explain the extra time because the increments are at 48m and 51m and "by the book", you always round up (towards the surface, i.e. down to the smaller number).
Whether the avg. depth is (just under) 48m or 50m makes no difference.

And therein is yet another, somewhat questionable IMO, difference. We would round toward the deeper depth to increase conservatism, which would add a few more minutes of deco.

I have to admit I wasn't sure where you got the 48m average from. I find it very troubling that that it seems to come from rounding to the "aggressive" side instead of the "conservative" side, especially so since 2/3s rounds to a lessor number instead of a higher number (?!?). I assumed it was a typo until I saw your other post stating that procedure is "by the book". I truly hope that this is just a misunderstanding on your part as to the procedure.

In about 10 years of tech diving and training with multiple agencies and instructors, pretty much every calculation that was rounded was done to the side that was more conservative in order to increase safety. 2m/7' deeper average on a dive can make a difference.

At this point I think it may be prudent for you to get clarity on the subject by just contacting AG. I'm sure he could explain his decisions better than any one else.

 

[cathal]

To answer your question: "So why on earth should we be holding on to that [RD]?"

I personally find that its application offers me a very practical way to plan and execute dives, I feel that it's a very strong educational tool and I find that it's helpful during my progression.

That's all there's to it.

Sorry but this just smacks of confirmation bias, its the exact same as saying I prefer to count time in my head as opposed to relying on a Casio G Shock as that watch could fail and then what? Its outdated thinking soaked in confirmation bias. Get a computer and for decompression diving get two, its that simple.

 

[Dan_P]

I have to admit I wasn't sure where you got the 48m average from.

It really doesn't need to be problematic if you don't want it to be. In either case, I'm not saying that all this speaks to the advantage of RD1.0 in the findings - it's just that I think we ought to be careful about drawing on a linear logic for conclusions about degrees, is all (e.g. how much RD1.0 was overemphasising deep stops, or how inefficient it was compared to GF30/85). I really don't think there's anything controversial in that, at all.

As for the average depth, in fairness though, if we sum the depths in metres of every minute during the bottom part (granted, including descend), and divide that sum with the number of minutes in that timeframe, the total is less than 48.

Sorry but this just smacks of confirmation bias, its the exact same as saying I prefer to count time in my head as opposed to relying on a Casio G Shock as that watch could fail and then what? Its outdated thinking soaked in confirmation bias. Get a computer and for decompression diving get two, its that simple.

That's your opinion. It's my opinion that your post is oversimplifying what I'm using RD for.

I've said:
"I personally find that its application offers me a very practical way to plan and execute dives, I feel that it's a very strong educational tool and I find that it's helpful during my progression"

Which logic is it that you feel may be effected by confirmation bias, please?

 

[cathal]

That's your opinion. It's my opinion that your post is oversimplifying what I'm using RD for.
I've said:
"I personally find that its application offers me a very practical way to plan and execute dives, I feel that it's a very strong educational tool and I find that it's helpful during my progression"

Which logic is it that you feel may be effected by confirmation bias, please?

Your statement that "its application offers me a very practical way to plan and execute dives" the effort you spend on RD for ultimately an inferior decompression strategy as you call it, the logic that RD is a practical and strong educational tool in the age of computers like SW who have been and are proven on a daily basis by thousands of users to be superb in their application.

Keep it simple just use a computer. They are that reliable they even use them to fly planes!

 

[Jack Hammer]

As for the average depth, in fairness though, if we sum the depths in metres of every minute during the bottom part (granted, including descend), and divide that sum with the number of minutes in that timeframe, the total is less than 48.

Perhaps they calculate average depth differently than you. Only they can really say how they determined the numbers.

If starting the average once at the bottom it is 50m, if starting the average from the surface it is 46.7m (rounding to conservatism would be 48m, rounding to surface would be 45m). Just trying to understand how you are calculating the numbers you are stating as being the "correct" method.

 

[UWSojourner]

RD1.0 you'd have 1 minute at 36m, 33m, 30m, 27m and 2 minutes at 24m.
You'd then have a total of 15 minutes distributed across the 21m-segment and 15 minutes across the 6m-segment.
With the S-curve in RD1.0, it'd be 4 minutes at 21m, 4 minutes at 18m, 2 minutes at 15m, 2 minutes at 12m and 3 minutes at 9m. Then 15 minutes between the 6m and 3m stops.

Thanks for clarifying your UTD "ideal" 1.0 profile.

What does the UTD RD 2.0 profile look like? Can you post the profile so we can see the 2.0 adjustments?

 

[PfcAJ]

Your statement that "its application offers me a very practical way to plan and execute dives" the effort you spend on RD for ultimately an inferior decompression strategy as you call it, the logic that RD is a practical and strong educational tool in the age of computers like SW who have been and are proven on a daily basis by thousands of users to be superb in their application.

Keep it simple just use a computer. They are that reliable they even use them to fly planes!

Aight I don’t even like UTD ratio deco but your statement here really doesn’t hit the mark.

Being able to know what your deco obligation is going to be for a given depth and time is handy. Knowing what impact hanging out a bit shallower or deeper is going to have is handy. Knowing the impact of spending some extra minutes at depth is handy. Knowing what your computer should be saying is handy.

No method is perfect. Computers certainly aren’t. There’s strength in being able to use a variety of methods, tables, ratios, and computers.

 

[cathal]

Being able to know what your deco obligation is going to be for a given depth and time is handy. Knowing what impact hanging out a bit shallower or deeper is going to have is handy. Knowing the impact of spending some extra minutes at depth is handy. Knowing what your computer should be saying is handy.

No method is perfect. Computers certainly aren’t. There’s strength in being able to use a variety of methods, tables, ratios, and computers.

Can I ask what is knowing all this inefficient deco information, (per Spinsi Study) is handy for? If your worried about your primary computer failing, just use a 2nd computer. And if you suggest both computers could fail then can I suggest its time to stay at home.

Of course its handy to have a fair idea of what type deco you should be doing, but that's all, a fair idea. I certainly would not be relying on it.