Son of Deep Stops *or* Waiting to be merged with the mother thread...

[lowviz]

It is most unfortunate that an extremely intellectually interesting thread degenerated into a time-suck for the mods and it got shelved as such. Much has been lost for those following this thread when the experts in the field were halted.

Maybe we can all find common ground and restricted language so the gunfight at the "I'll be OK" corral can continue.

I'd like to draw a line in the sand for both sides of the struggle. Start at the simplest profile possible that is relevant to the discussion. No accelerated deco yet. How about just attending to a rank basic "big" dive. 250 feet. On air. Bottom time as long as you like but more than 60 min. US Navy Table 5. I did substantial homework on this. Why? I'll never dive anything that constitutes a big dive, but I want to know where the gremlins are. For me, scientific curiosity and advancement of the "art". Discovering what the experts know is also most interesting. Many gems were offered in this now locked thread, I would very much like it to continue. Bubble methods should show their effects (indirectly) through their shortened deco times. How much shorter and where do they start to prevail? Graphs please.

So let's try to make it better.

Attached are the USN Air Table 5 in its entirety, a snippet of that table (250 feet schedules for deco over one hour) that was curve fit and contains a calculator for depths and times all around that limited region, and a graph of the curve fit. Nothing is locked or protected. Anyone can inspect or alter anything in the workbooks. The range was limited to allow for a really good fit to the USN Air Tables total deco time. We have something to compare to. You can find the fitting equation in the workbook.

Could all previous points be made and defended by running profiles at various conservatisms etc on only 250 foot dives? I think so.

Comparison graphs consisting of only Depth, Bottom Time, and Total Deco Time would be insanely interesting.

Mods, feel free to delete without comment if this thread is over the line...

 

[nadwidny]

It is most unfortunate that an extremely intellectually interesting thread degenerated into a time-suck for the mods and it got shelved as such. Much has been lost for those following this thread when the experts in the field were halted.
.

Whatever needed to be said was said. Over and over. Nothing was lost, you just need to go back and read it...from the beginning.

 

[lowviz]

I followed it most carefully. Then tell me, where do the bubble models irresponsibly diverge from Haldanean models?

Bubble models are overly safe at recreational depths and times but are irresponsibly aggressive on the very big dives. How far can I trust bubble models?

That was never answered.

 

[rossh]

Some of your longer times are getting into the "exceptional" regions of air diving. Its poking around in the unknown, and poorly dived and poorly recorded areas. And its not in rec /tech diving arena.

So all very hypothetical.


All dive models have increasing risk with increasing exposure. Its how its always been done, in navy models too, because the user wants to get out of the water in timely manner - that is the criteria placed on the design. This trying to single out bubble models for being like all others, is being prejudicial.

One can of course design a plan with stable risk, or no risk. There is no mystery in how to do this. But no one will use it, because no one can afford the exponential time increase it requires.

.

Commercial footnote: We make a program called MultiDeco. It has most of the current deco models and variations available for you to choose from. Your welcome to choose any model, and to do as much, or as little deco time as you want - its your choice.

 

[lowviz]

Ross,

Thank you. Your point is taken. Is the range given below more appropriate to the discussion?

 

[lowviz]

...//... This trying to single out bubble models for being like all others, is being prejudicial. ...//...

Not my intention at all.

Bubble models are based on a different set of assumptions than pure dissolved gas models. Whether or not these bubbles even exist is completely irrelevant to comparing how traditional models and bubble models differ in practice.

 

[PfcAJ]

All dive models have increasing risk with increasing exposure. Its how its always been done, in navy models too, because the user wants to get out of the water in timely manner - that is the criteria placed on the design.

One can of course design a plan with stable risk, or no risk. There is no mystery in how to do this. But no one will use it, because no one can afford the exponential time increase it requires.

.

Commercial footnote: We make a program called MultiDeco. It has most of the current deco models and variations available for you to choose from. Your welcome to choose any model, and to do as much, or as little deco time as you want - its your choice.

Such baloney. Absolute 100%, grade A baloney.

You're really saying that the increase in risk is INTENTIONAL? GTFO

 

[lowviz]

Oh my. Just came in from yard work and now this. Sandbox rules, please.

Fine by me if the risk is intentional. Where is it and how much???

 

[rossh]

Such baloney. Absolute 100%, grade A baloney.

You're really saying that the increase in risk is INTENTIONAL? GTFO

Go look at any published pDCS chart. The numbers rise with exposure. Increasing risk is accepted way of dive planning.

Go ask David. "nature of the task' is how he described it at TekUSA.

 

[PfcAJ]

Go look at any published pDCS chart. The numbers rise with exposure. Increasing risk is accepted way of dive planning.

Go ask David. "nature of the task' is how he described it at TekUSA.

Its not intentional though. Its because the models are ******. Its accepted only because there's no other commercially available method outside of manipulating gradient factors.