UTD Decompression profile study results published

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What I am referring to is a summary. i.e. you dialed in a 50/80 but unless you execute the dive perfectly, you dive something different than what you dialed in. Shearwater should be able to recalculate the dive and give a GF total of the dive. This would hopefully demonstrate that most divers are actually EXECUTING a GF that is lower than the limits set.
 
I don't know what "GF total" would mean.

Do you want to know the GF99 value from when you reach the surface? Do you want to know the maximum GF99 value that you hit at any time during the dive? That could definitely be higher than your GF99 when you hit the surface.
 
It seems obvious to me that if you're not following the ceiling "spot on" (which is impossible, due to the fact we divide the ceiling in 3m steps), you will not be following the GF you dialed in, but something lower. What did I miss that makes this something requiring demonstration?
 
It seems obvious to me that if you're not following the ceiling "spot on" (which is impossible, due to the fact we divide the ceiling in 3m steps), you will not be following the GF you dialed in, but something lower. What did I miss that makes this something requiring demonstration?
Because most divers think that they actually dive a GF that they dialed in when in fact they are way lower than that. Most don't get that - that's why I make the point. Good for you if you got it
 
Because most divers think that they actually dive a GF that they dialed in when in fact they are way lower than that. Most don't get that - that's why I make the point. Good for you if you got it
My response is a bit more general than this but is on the same general idea.

I think a lot of people do things on a dive that are a lot different than what they intend to do or even think they are doing. I just finished making a post about two friends who got bent using UTD's Ratio Deco. They thought they had followed the plan perfectly. One of them was using a computer in gauge mode, so they had the computer's log, and when they checked, they found they had made three significant computational errors during the dive that undoubtedly contributed to their DCS.

In contrast...

Last year i was on a dive boat with several groups of divers doing a decompression dive on a wreck. The DM went about asking for planned run times, and the two longest ones were my group and a pair of rebreather divers. We were both planning the same dive using the same algorithm with the same GFs. As you would expect, my group arrived at the ascent line at almost the same time they did, and we started up the line ahead of them. I watched my computer ascent rate carefully, and we stayed pretty close to 30 FPM all the way to the first stop. When I got there, I looked down, and the rebreather divers were not in sight. I was a bit worried, and I kept looking down as I did those first few short stops. Eventually I could make them out. They were far below us. They ended up doing something like 10-15 minutes more deco than planned, and on the boat they said they couldn't understand it. As they ascended, the computer kept adding more and more deco time. I said, "Well, you guys were ascending really slowly." One of them said, "You're supposed to ascend really slowly."

What's the difference? In both cases, the divers made mistakes that impacted their ascent profile. In the first case, they had no way of knowing it. In the second case, the computer knew they had made the mistake and told them what to do about it.
 
fascinating
 
Because most divers think that they actually dive a GF that they dialed in when in fact they are way lower than that. Most don't get that - that's why I make the point. Good for you if you got it
I doubt the point is important enough to warrant a change in Shearwater's software. The fact there is a difference should suffice. The actual number has little value.
 
A quick note to summarise my thoughts on this:

I think, relatively, there's more to this and other discussions on matters DIR and UTD that comes from the "DIR wars" than what I can personally relate to. Naturally so because I wasn't around diving at that time.

I wasn't around for the invention of the Aqualung either, so obviously, that first system doesn't effect me either on an emotional level.

Don't get me wrong, I might feel differently about it all if I were already a diver then, doing things differently back in those days, and all of the sudden, someone was telling me that I was in desperate need of a body bag as my next accessory purchase - but, seen in context, some form of reaction to the circumstances that be/were is very human, and understandable.
No fingers pointed from this seat, in either direction.

But context is often left out, and a lot has changed since then.
Either way, it doesn't prompt bashing some twenty years later.

One can say that UTD or any other organisation for that matter, do something that one doesn't agree with, for whichever reasons one might have. That's perfectly fine.

When it comes to Ratio Deco, it has evolved since the original version. The italian project found ways to optimize it, and so it was optimized. That doesn't mean it's broken. It has great advantages, which one might choose to utilize, or not. The same, by extension and relation, goes for standard gasses.
The heart of Ratio Deco is that it's a strategy, and can be adjusted. If I'm far away from the nearest chamber, remote in icy water and I'm not perfectly hydrated or a bit fatigued, I adjust. One would be hard pressed for an empirically proven deco profile that accounts for all those variables regardless.

Either way, if one is curious about it, it's worth learning about it.

The Z-system is another punching bag. Most of the bashing of it I've seen comes from people who haven't even trained and dived it, and fails to touch on the pro's and con's of it's use. Also in this case, there are advantages that one can choose to utilize, or not.
For some dives, a set of backmounted doubles is a good tool. For others, not so. But it is what it is; I simply cannot add an extra tank into the isolatable "loop" when I need to. So when we do a 1:3 decompression rate, we use the "perfect" tool 1/3 of the time, and indie singles 2/3 of the time. Many of the people quick to denounce the Z, denounce indies with even more vigor. It's a paradox.

The MX-rebreather also got bashings online, sometimes in the form of the most heinous language, people crying wolf, etc. Still zero fatalities.
From an organization that is - unless I'm mistaken - the only one who has managed to have any insurance agency sign them a policy, and with zero incidents, across the board.

It's a bit more nuanced than this discussion would let believe - it's almost, but not quite, like comparing a restaurant's gastronomical theme to the recipe of a single dish.

If you want to know about a system, be it gear or decompression, go talk to an instructor about it, learn it and then make up your mind. It'll give you a much more nuanced body of knowledge to make up your mind from, than anything I or anyone else pours out on an internet forum.

That's all.
 
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The MX-rebreather also got bashings online, sometimes in the form of the most heinous language, people crying wolf, etc. Still zero fatalities.
From an organization that is - unless I'm mistaken - the only one who has managed to have any insurance agency sign them a policy, and with zero incidents, across the board.
What insurance company covers your agencies rebreather program? I know it's not Willis anymore.

Also zero accidents on a system that only has a small handful of units is hardly an accomplishment.
 
My response is a bit more general than this but is on the same general idea.

I think a lot of people do things on a dive that are a lot different than what they intend to do or even think they are doing. I just finished making a post about two friends who got bent using UTD's Ratio Deco. They thought they had followed the plan perfectly. One of them was using a computer in gauge mode, so they had the computer's log, and when they checked, they found they had made three significant computational errors during the dive that undoubtedly contributed to their DCS.

In contrast...

Last year i was on a dive boat with several groups of divers doing a decompression dive on a wreck. The DM went about asking for planned run times, and the two longest ones were my group and a pair of rebreather divers. We were both planning the same dive using the same algorithm with the same GFs. As you would expect, my group arrived at the ascent line at almost the same time they did, and we started up the line ahead of them. I watched my computer ascent rate carefully, and we stayed pretty close to 30 FPM all the way to the first stop. When I got there, I looked down, and the rebreather divers were not in sight. I was a bit worried, and I kept looking down as I did those first few short stops. Eventually I could make them out. They were far below us. They ended up doing something like 10-15 minutes more deco than planned, and on the boat they said they couldn't understand it. As they ascended, the computer kept adding more and more deco time. I said, "Well, you guys were ascending really slowly." One of them said, "You're supposed to ascend really slowly."

What's the difference? In both cases, the divers made mistakes that impacted their ascent profile. In the first case, they had no way of knowing it. In the second case, the computer knew they had made the mistake and told them what to do about it.
yup, last week racked up some deco, because the place i decided to do my stops was deeper than my Shearwater wanted (based on what I told it I wanted)..racked up some more deco while doing deco. I just wanted to stay out of the flow..and play with my camera.. :)

That said, if folks are doing deco dives not understanding that and the why, they need to take a step back and lean some of what "they don't know what they don't know)
 
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