PerroneFord
Contributor
Jason B:
JasonB, my apologies. For some reason I assumed you were GUE. I guess since I saw you posting quite a bit in the DIR area. I'm sorry I made that assumption.
which deco software?
- Thread starter H2Andy
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
JasonB, my apologies. For some reason I assumed you were GUE. I guess since I saw you posting quite a bit in the DIR area. I'm sorry I made that assumption.
OP
H2Andy
Contributor
Jason, this is a simplistic answer, as i am just starting to do deco cave dives myself
since we plan our dives on thirds, the amount of gas we carry with us will
be the determining (time) factor.
we then check the cave maps for depths (they are marked in the good maps)
or talk to experienced cave divers (what's the max depth if i make the Hill 400
jump? etc.)
based on those two things, you can get a sense of how much into deco you
are going to go.
so far, we've had only light deco obligations (less than five minutes), and we
use O2 on the last 20 feet to boot.
since we plan our dives on thirds, the amount of gas we carry with us will
be the determining (time) factor.
we then check the cave maps for depths (they are marked in the good maps)
or talk to experienced cave divers (what's the max depth if i make the Hill 400
jump? etc.)
based on those two things, you can get a sense of how much into deco you
are going to go.
so far, we've had only light deco obligations (less than five minutes), and we
use O2 on the last 20 feet to boot.
Thanks Andy. I know its a tough call really. As river levels change, so do flow rates and it seems that the time (since it is determined by pressure -thirds) will not always yield the same results. I know when the flow is down, I can get a lot further into a system than when it's kicking. I'm sure experience plays a big role in this planning as well.
But if I'm reading you right, it sounds like you are basing this off the max depth you will encounter (square profile). Is that correct? That may be the only way to "pre-plan" the dive. I guess for planning the amount of deco gas needed that would be the smartest way to go about it.
But if I'm reading you right, it sounds like you are basing this off the max depth you will encounter (square profile). Is that correct? That may be the only way to "pre-plan" the dive. I guess for planning the amount of deco gas needed that would be the smartest way to go about it.
The whole problem of not knowing the profile in advance is just begging for ratio deco.
But I'm under the impression that H2Andy is not deco trained at all at this time. I might be mistaken on this, no offense intended.
But I'm under the impression that H2Andy is not deco trained at all at this time. I might be mistaken on this, no offense intended.
OP
H2Andy
Contributor
what is ratio deco?
JeffG
Contributor
It is a technique taught by Gue instructors to generate a deco profile. In the internet world it is also know as "Deco on the fly"H2Andy:
Jason based on your original questions there are a few ways to look at this.
First it is important that everyone understand that NOBODY can predict who will, when and under what circumstances become a victim of DCS.
With all the various softwares out there you need to look at what they can do and the information they provide. YOU NEED TO DECIDE WHAT PROGRAM and HOW YOU WANT TO MAKE A DECO DIVE. Talk with others to see what they have done and how they do it and what they use to plan it. Deco diving is a personal thing each and every time.
A way to look at Jason's question should you not have the luxury of knowing the dive site or having talked to anyone about it, is that you can ratio by tables or computers or purely computer fly. These are not always the best way to go about it but they are not really a wrong approach either. Remember NO ONE CAN PREDICT....... you get the idea.
The following is and example of what I did during a dive in the Yucatan to a depth of just better then 200 ft in a unexplored cenote, which we plummed the depth first to the debris mound.
Since you may not know the dive site you can pick a set of pre determined depths, example say 60 ft, 100 ft, 130 ft. Run or review tables for these depths. Calculate your air requirements based on the deepest depth and for the greatest amount of time you plan on spending with considerations to the environment you are diving in. Your greatest amount of time is at least 5 minutes greater then you actually would spend at depth. You would also run tables for the exact time and 5 minutes less then you plan. Now during the dive if you realize that you do not get to your greater depth you will have the tables to still follow. As it is not likely at 130 ft that you would have a deco stop at 60 ft just hold to your times and deco stop points anyway. If you have computers (you should have two) then you could fall back on them. I would not increase my time though because I'm at a shallower depth, not a good choice. Major conservatism here you and may even consider doing the time solely as if on straight air. Just exit and replan for another dive to the depth you reached. You are now exploring the dive site
Now if the depth is greater then what you planned for it is simple just don't go deeper than your planned depth and times. Surface and replan to make another dive later at the new greater known depth.
Remember depth air and time are the controlling factors of any dive anytime you reach one of these marks you turn the dive and exit, in the case of a cave you can also add penetration distance as another factor
Something to consider???
First it is important that everyone understand that NOBODY can predict who will, when and under what circumstances become a victim of DCS.
With all the various softwares out there you need to look at what they can do and the information they provide. YOU NEED TO DECIDE WHAT PROGRAM and HOW YOU WANT TO MAKE A DECO DIVE. Talk with others to see what they have done and how they do it and what they use to plan it. Deco diving is a personal thing each and every time.
A way to look at Jason's question should you not have the luxury of knowing the dive site or having talked to anyone about it, is that you can ratio by tables or computers or purely computer fly. These are not always the best way to go about it but they are not really a wrong approach either. Remember NO ONE CAN PREDICT....... you get the idea.
The following is and example of what I did during a dive in the Yucatan to a depth of just better then 200 ft in a unexplored cenote, which we plummed the depth first to the debris mound.
Since you may not know the dive site you can pick a set of pre determined depths, example say 60 ft, 100 ft, 130 ft. Run or review tables for these depths. Calculate your air requirements based on the deepest depth and for the greatest amount of time you plan on spending with considerations to the environment you are diving in. Your greatest amount of time is at least 5 minutes greater then you actually would spend at depth. You would also run tables for the exact time and 5 minutes less then you plan. Now during the dive if you realize that you do not get to your greater depth you will have the tables to still follow. As it is not likely at 130 ft that you would have a deco stop at 60 ft just hold to your times and deco stop points anyway. If you have computers (you should have two) then you could fall back on them. I would not increase my time though because I'm at a shallower depth, not a good choice. Major conservatism here you and may even consider doing the time solely as if on straight air. Just exit and replan for another dive to the depth you reached. You are now exploring the dive site
Now if the depth is greater then what you planned for it is simple just don't go deeper than your planned depth and times. Surface and replan to make another dive later at the new greater known depth.
Remember depth air and time are the controlling factors of any dive anytime you reach one of these marks you turn the dive and exit, in the case of a cave you can also add penetration distance as another factor
Something to consider???
PaulChristenson
Contributor
JeffG:
Then you are SOL...
TSandM:
This isn't meant to be a GUE or DIR bash, so please don't take it that way, but blindly following anything that you're taught in class, without taking the time to fully undertand what it's telling you and why, is probably one of the most foolish things you could do. Spend the $80 bucks on the software, and start playing with different profiles, and you'll start to see some of the patterns emerge yourself. I think ratio deco is a great tool, but it shouldn't be the only one in your bag of tricks.
Bruce
Similar threads
