Your Gradient Factors?

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Wow.. and I thought this thread was just a simple question. I love these threads do not get me wrong but I do believe they do go way off on their own little tangents. I'm using 45/95 nothing more nothing less.

Your Gradient Factors?
 
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OK, let me try it this way.

Of the openly available published dive tables, NONE use average depth of the dive in any way. There may be some who think they have discovered some cool way to use average dive depth, but they have no mathematical justification for it and no independent verification that it works. Same with thos that think they can do multilevel dives with a single-level dive table.
Well...
Some European tables officially use avg depths of the dive.
Comex comes to my mimd.
They are freely available as its use has even been published as legal requirements for people using them under professional activities.
And yes, like USN or other pro tables, they are/were used by rec divers under the name of "tables MT 92".
Will try to post a pic of a submersible table later.
 
I thought for a long time in this discussion that people were simply moving goal posts. Now I see that they have not even agreed on what the dame is.

I thought the statement that you can use average depth with tables and get effectively the same answer was what was being said, and that such a practice was widespread.
Now you are saying that your point is you get a safe answer, but not the same answer. OK.
But then the other players are not even using average depth of the dive, but rather average depth of the bottom (or the deep segment of the dive) as far as I can tell. Totally different game. Then others are arguing about 4h dives or trimix or saturation or something. Different game, not even the same playing field. And some say well that's what we do locally, which is hardly "widespread."

It certainly appears that the DIR/GUE/UTD guys doing heavy deco have figured out a way to do some sort of (to me arbitrary) averaging that allows them to mostly stay away from DCS. Great.

But folks using the usual tables, from the mainstream agencies, really ought to avoid this "average depth" nonsense. It demonstrably does not work to give the same answer as their max depth and the tables. yes, it may provide a safe answer, although that has not really been shown...just some example where it does work. It would be even safer on a multilevel dive to just use the max depth -- as the tables intended -- and accept that the dive will be shorter than desirable. Or use a multi-level diving tool. Or use a damn computer.

I'm not sure Tursiops, what your goal here is. To warn recreational divers not to use average depth when planning a dive using tables? For sure... but this is a given. They have no knowledge of decompression theory and are using computers in any case. So what is really the discussion? The inital question was on what GF are used. That's in itself not a recreational question, so excuse me for replying to this question explaining how i plan technical dives.

Will I use max depth as my planning depth when doing a recreational dive... yes I probably will, because it's easier (no calculation) and adds a bit of conservativism to the dive... or I just switch the gauge to computer and dive a computer and switch my brain off :yeahbaby:But the initial discussion was on GF, and that's in itself not a recreational discussion, and I just said how I plan technical dives.

- We are not moving goal posts. Calculating avg depth and using it in your dive planning (even on the fly during the dive) is part of the standard GUE procedures and is taught in the curriculum. If you want to look it up I'm sure you'll be able to find the GUE procedures.
- Calculating/using the average depth of the bottom part of your dive (non ascend) is a perfectly feasible way of planning a dive and in reality because the variance between min (bottom) depth and max (bottom depth) is reasonably small. You might say this is anekdotal and not supported by science, but I have done 100s of trimix dives doing this like others and it just works.
- Doing deep and long dives with extended deco (2 hours plus) is in any case only marginally supported by theoretical models. When the switch between different models or adjustment of GF can mean the difference of hours less or more deco, it becomes all very grey in any case and people/teams make individual decisions.

So unless you come up with some hard data that using average depth in the bottom part of technical dives is less optimal I won't change my mind. I'm not seeing Dr. Mitchell or the NEDU team jumping in here to support your case :D
 
The initial post that started the "average depth" discussion talked about waiting for the average to reach a certain magic number then rocketing to the surface. Anyone care to address that? The subsequent posts seem to be about other ways to use average depth in dive planning.
 
The initial post that started the "average depth" discussion talked about waiting for the average to reach a certain magic number then rocketing to the surface. Anyone care to address that? The subsequent posts seem to be about other ways to use average depth in dive planning.

The initial post was from me and I would like to know where I said "rocketing to the surface" or are you making this up? Below the part in my original post on average depth.

Next to deco plan and/or shearwater I also check the average depth at certain depths to see if I'm on deco target, meaning on deeper dives I don't want to get out of the water with an avg depth of more than x and I also don't want to move up from 9 to 6m before my avg depth reaches a certain depth even if the plan or computer says I can move up.

I'm not going to mention the depths I use, because I don't want to feel responsible for someone elses experimenting, but I'm sure if you do enough dives you'll see a certain correlation.

cheers

B

PS: I see someone else already mentioned avg depth (Ralph) ;-)

I would never "rocket" to the surface, on any dive. On a rec or shorter tech dive I would gradually ascend from 6-3m to the surface taking at least 1 minute or even more. If I'm doing bigger dives I'll ascend from last decostop to the surface at 1' per meter ascend (so 6' from 6m). The respective pressure change from 6m to the surface is so great that a "fast" ascend to the surface can court disaster on bigger dives. Even when I'm teaching recreational students I'll always tell them that after a safety stop has finished the ascent is still an ascent and should be reasonably slow and deliberate.
 
I’m not directing my comment at any one person, just sharing my perception about this thread in general.

The amount of effort going into the discussion (perhaps litigation) does not have, for me, a commensurate value in useful output towards a durable assertion.

I acknowledge I very well may be too junior to appreciate the subtleties.

Alas, I’m back home in Florida (vice Saudi Arabia) where I’m no longer starved for competent technical divers that I have to turn to the internet to augment what I learned in coursebooks.

As such, this thread will probably have little bearing on the team plan I’m putting together for a normoxic and staged jump of the Oriskany in April.

But maybe I have misunderstood the intended application of this forum all along.
 
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I'm not sure Tursiops, what your goal here is. To warn recreational divers not to use average depth when planning a dive using tables? For sure... but this is a given. They have no knowledge of decompression theory and are using computers in any case. So what is really the discussion? The initial question was on what GF are used. That's in itself not a recreational question

Fact is on many dive computers there are 3 default GF to choose from for recreational divers.
 
a multilevel table :)
20201125_184133.jpg
 
https://www.shearwater.com/products/perdix-ai/
http://cavediveflorida.com/Rum_House.htm

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