Ongoing discussion of Ratio Deco

[rjack321]

Hmmm a 3 person team already? Guess there's no room for God on this dive. Make sure you don't invite him!

:weakest:

 

[ScubaMilo]

Hmmm a 3 person team already? Guess there's no room for God on this dive. Make sure you don't invite him!

:weakest:

I think we might be able to use him as surface support or saftey diver.
What do you say we might actually need his services to pull this off?

Milo

 

[rjack321]

I think we'd need more than just a prayer.

His son has a fast scooter, I'll see if he's free.

 

[ScubaMilo]

:11:

I get it.
You want to argue about scooters next.
(just kidding, for those that might not see the humor)

Milo

 

[atedeschi]

I was wondering if anyone has any good links to articles on ratio deco and/or minium deco. Have an idea about both but wanted to get filled in alittle better.

Thanks

 

[Phil K.]

A few months ago I found a big nasty error in DPlanner. I emailed the support and never heard back. There's still an error in the program, and it seems no one cares. Scary.

D Plan and Deco Planner are not identical programs. I thought from your original comment that you believed that D Plan had this error. Your later posts refer to Deco Planner as the program that has this error. I just checked D Plan. It defaults to 10/70 as the standard gas for a dive to 300', so I gather that none of this applies to D Plan.

 

[limeyx]

Let's see, avg depth of about 217fsw for 60min let's round it to 230 just to be safe.
Ratio deco says:125min of deco
Hmmm.......

Milo

You mean 125 mins deco or runtime? The other figures were total runtimes I think.

Disclaimer: I am by no means trained to plan a dive anywhere close to this, but
the deco between 200 and 300 I am pretty sure is not linear, therefore a straight linear average depth is not going to work.

Of course, the amount of gas needed to perform this dive (and to keep a decent reserve) is huge, especially when dipping back down to 200

The only way I could imagine to plan it is

the 300 section gives you 60 mins (3:1) deco above 120
Ascend to 150 doing deep stops.
Since you are somewhat offgassing at 150, maybe the 20 min segment there gives you 10 more mins deco.

THen back to 200 for 20, which adds 40 more mins deco

= 60 mins (BT) + 60 (300) + 10 (150) + (40) + deep stops to 150, plus deep stops from the final 200 foot portion
so you are talking 170 + deep stops(20-30 min for 60 min BT) + some 30fpm ascents to 150 and from 200, so assume 5 mins there, or about 195-205 mins

Still shorter than the other planners by a bit.

(I could be waaaaay off base here tho

How much gas would one need for such a dive? I am guessing not entirely practical outside of a cave on open circuit.

 

[Kevrumbo]

Let's see, avg depth of about 217fsw for 60min let's round it to 230 just to be safe.
Ratio deco says:125min of deco
Hmmm.......

Milo

I've figured for 220fsw @ 60min. bottom time on 15/55 mix:
165min. Deco Time, with 10min to progress thru the Deep Stops on 21/35mix; 33min total time at the 35/25mix deco stops; 66min. total time at the 50% Nitrox stops; and 66min. at 100% O2 stops (intense 1:3 RD and gas planning exercise --anybody who just took the Class with me concur with these figures?)

 

[rainman_02]

D Plan and Deco Planner are not identical programs. I thought from your original comment that you believed that D Plan had this error. Your later posts refer to Deco Planner as the program that has this error. I just checked D Plan. It defaults to 10/70 as the standard gas for a dive to 300', so I gather that none of this applies to D Plan.

What I get for typing tired. I'll correct the original post. Thanks.

But it does bother me that there is the possibility for an error in the program and no one gives a hoot. Whatever. Ignore the man behind the curtain.

 

[FishTaco]

What I get for typing tired. I'll correct the original post. Thanks.

But it does bother me that there is the possibility for an error in the program and no one gives a hoot. Whatever. Ignore the man behind the curtain.

Not true, I do care, thanks for pointing it out.
I'm just not planning on diving a profile like that,besides, Milo and rjack already have a 3rd teammate...Darwin took my spot.

Take care,
Chris