Ongoing discussion of Ratio Deco

[Big Kahuna]

We think that Milo is way over the top! Cool off buddy!!!

 

[amascuba]

We think that Milo is way over the top! Cool off buddy!!!

we? Forget to take your meds today?

 

[ScubaMilo]

We think that Milo is way over the top! Cool off buddy!!!

Ok, I'm cool.

So how exactly do you find me over the top?

Milo

 

[rainman_02]

Buhlmann says I should be bent like a prezel cause I didn't even start off-gassing according to him until 35ft or so.

Try closer to 100-110 ft. This is why your arguments are so frustrating to some people...you demonstrate a lack of understanding of the models to which you're comparing profiles.

RD uses "80% ATA (75% depth)" as an approximation of the commonly calcuated start of decompression zone where the leading compartment has a gradient to off-gas. Just the same as running a VPM-B profile (deco zone starts ~2 ATA less than bottom) or running a (GF Low=5 to 10) Buhlmann profile.


Decompression is inexact. And you'll never convince them that their methods are "wrong" any more than they'll convince you that your methods are "wrong."

 

[Kevrumbo]

let's stretch the bottom time a little say to 40 min. still within ratio deco's Tech 1 limits acording to AG's paper.
We'll use 21/35 or 18/45(w/ean50 for deco).
As stated earlier in the thread and also by AG there should be no real difference.

___________ratio deco________D-plan(GF 80/35)_______21/35______18/45
Depth______21/35-18/45______21/35______18/45_____difference___difference

130fsw_______30min__________35min_____------______5min________-------

140fsw_______35min__________40min_____------______5min________-------

150fsw_______40min__________47min_____------______7min________-------

160fsw_______45min__________52min_____61min_______7min________16min

170fsw_______50min__________60min_____68min_______10min_______18min


So it's easy to see when you get further from the sweet spot ratio deco begins to really show it's inconsistency.

Especially when compared to the 18/45 profile of d-plan.
These are drastic differences when compared as percentages.

This is just one example but there are many others.
I encourage the ratio deco believers to spend some time doing the comparisons.

I will say once again ratio deco is a great tool but should not be used without caution as it is inconsistent outside of certain ranges.

Just a word of caution,
Milo

I would agree with you in the fact that these should be 2 bottle dives but this is not inaccurate.
The values come directly from page 15 of the only known written text by AG on the subject of ratio deco.
So if it is wrong it's not me that's wrong.

Thanx,
Milo

It's not wrong . . .you forgot to figure in the Deep Stops in RD (again! -study p. 7)
160' has 7min total, while 170' has 10min.

 

[ScubaMilo]

It's not wrong . . .you forgot to figure in the Deep Stops in RD (again! -study p. 7)
160' has 7min total, while 170' has 10min.

I thought we agreed many pages ago that deep stops would be added to either ratio deco or d-plan.
So we are talking deco time on the bottle.

Which again would make the table an accurate representation of the total deco times after the gas switch.

Thanx,
Milo

 

[limeyx]

We think that Milo is way over the top! Cool off buddy!!!

Thats a bit harsh. Milo is a cool guy, and a very good/safe diver -- almost certainly a better diver than myself. (I have dived tech1 dives with him before and would easily dive with him anytime).

We are just having a civil discussion over our slightly different approaches to deco.

no fighting, no mud-slinging.

 

[ScubaMilo]

Thats a bit harsh. Milo is a cool guy, and a very good/safe diver -- almost certainly a better diver than myself. (I have dived tech1 dives with him before and would easily dive with him anytime).

We are just having a civil discussion over our slightly different approaches to deco.

no fighting, no mud-slinging.

Thanks Limey,

Although I wouldn't go so far as to say I was a better diver, but thank you for the complement.

I would most certainly not hesitate to do more diving with you also.

Safe diving,
Milo

 

[grazie42]

I got a bit bored on this thread the other day so I started the same discussion in another forum...
"We" finally decided that deepstops are a part of RD, but not the other models...the other profiles are also changed so that descent is not part of the BT, ie 40m-profile is actually 32mins before ascent, not 30mins...this was suggested by rossh (who created v-planner)...
I just figured this thread might benefit from the "fruits of our labour"...there is still some disagreement about the profiles (who would have guessed? ) but this is what the table looks like at the moment...

 

[ScubaMilo]

I got a bit bored on this thread the other day so I started the same discussion in another forum...
"We" finally decided that deepstops are a part of RD, but not the other models...

With all due respect,

In the DIR forum where DIR answers are required.
Deep stops would be a part of D-plan as taught by GUE.
When this program is used as it is taught by GUE, deep stops and shaping of the curve are included.
Where do you guys think AG got his deep stop protocol for ratio deco from?
Therefore to exclude these stops from D-plan would in my opinion be considered a non DIR answer.
Since these protocols clearly came from GUE first.

In another forum under different circumstances(program used without GUE training) I could see your point.

Sincerly,
Milo