Manual calculation for accelerated deco

[Dan_P]

Why is Dan_P going on and on about buoyancy control?

It's been a lengthy discussion, transcending this string Elaborating below

Goalpost movement.

It’s always something else with the utd ratio deco guys. Always.

As for football analogies, it'd suit you to aim for the ball when tackling...

That could be one application of the concept, but it was not the one I was thinking of.

That's what I was referring to with the "burp"-remark, following a previous conversation you and I had about bouyancy at altitude.

I think the math I presented in the earliest post in which I went over things in detail was too much for some people, so I will make one point in the easiest possible terms.

1. When a diver exits the water, it is critical that tissue pressure be within a critical gradient range in relation to ambient pressure.
2. At 2,000 meters, the ambient pressure (0.8 ATA) upon surfacing is 20% less than it is at sea level (1.0 ATA).
3. This means the diver's tissue pressure must be considerably less than it would need to be when surfacing at sea level.

Firstly, I think we can agree that's too oversimplified, and the 20% you mention here, is completely incontextual.

Secondly, I'm not saying that the decompression aspect is unaffected by altitude - you're the one force-feeding that statement.
I've said loud and clear that I personally subscribe to extended shallow stops.

In honesty, I probably wouldn't even bother spending time on retorts if I weren't bored with your jumping at every chance to bash UTD.
That's all.

 

[tursiops]

In honesty, I probably wouldn't even bother spending time on retorts if I weren't bored with your jumping at every chance to bash UTD.

You sound more confused and desperate than bored. Whatever. Good luck at altitude.

 

[Dan_P]

You sound more confused and desperate than bored. Whatever. Good luck at altitude.

Pretty petty, but allright.

 

[lowviz]

...//... 2) I would argue the increased relative pressure difference is neglible (more on this below), and in either case this would prompt an increased emphasis on deep stops. ...

...//... I've said loud and clear that I personally subscribe to extended shallow stops.

I sense that progress is being made...

 

[Dan_P]

I sense that progress is being made...

Nothing changed.

1) From the context of what you're quoting, and the onset of this conversation, you'll see that I've consistently acknowledged that altitude has some impact on physiological decompression - but I think that in terms of bouyancy control, it's just a bad excuse for worse skills.

2) In terms of scientific proof for any one model or algotithm, no solution has that, so I think bashing anyone for not presenting it, is ridiculous.

3) Personally, I think Ratio Deco is a handy tool. I can and do adjust for various factors, including altitude, to the best of my knowledge.

That about sums it up.

 

[lowviz]

Nothing changed.

*sigh*

1) From the context of what you're quoting, and the onset of this conversation, you'll see that I've consistently acknowledged that altitude has some impact on physiological decompression - but I think that in terms of bouyancy control, it's just a bad excuse for worse skills.

Depth and time also have some impact on physiological decompression. It is all the same stuff. I won't even speak to buoyancy control as it is not the least bit germane to this issue.

2) In terms of scientific proof for any one model or algotithm, no solution has that, so I think bashing anyone for not presenting it, is ridiculous.

First, stop being so defensive. This is a discussion and it is up to you to support your position.

Decompression (theory or practice) has nothing to do with scientific 'proof'. There is no 'proof'. It is the science of numbers, statistics. An average diver diving any chosen decompression scheme will have a 0.XX% chance of an unfavorable outcome.

The statistics work so well over large numbers of divers that subgroups have been identified. Like people with PFO's. I see nothing of substance in any of your posts.

What, exactly, do you base your knowledge on?

3) Personally, I think Ratio Deco is a handy tool. I can and do adjust for various factors, including altitude, to the best of my knowledge.

I do too. I use something even cruder and it works for me.

That about sums it up.

Me too.

 

[Dan_P]

There is no science behind it.

It started with that.
Actually it started long before this thread, with statements that - in fairness - I think would make anyone object.
But, for the sake of this conversation:

Decompression (theory or practice) has nothing to do with scientific 'proof'. There is no 'proof'. It is the science of numbers, statistics. An average diver diving any chosen decompression scheme will have a 0.XX% chance of an unfavorable outcome.

My point exactly.

I won't even speak to buoyancy control as it is not the least bit germane to this issue.

I agree.

This is a discussion and it is up to you to support your position

My initial position was simply it's ridiculous to single out an approach to ascend planning because "there is no science behind it".
From your post, I believe you to agree with that statement.

From there, it became a myriad of having to answer for the way I dive.
Obviously, that does get tiring, I believe for everyone, but here's another crack at describing my logic, as for the altitude question at hand.
I'll try to disambiguate here so we're not mixing up different topics:

If the relative pressure difference is greater on an altitude dive, then that would impact both bubble propagation by way of gas mechanics to a greater level than "normal" (sea level), and dissolution of gas by way of an increased relative gradient across ambient and tissue.
That is, the degree of impact on bubble size from bubble mechanics would be greater than "norm". As I know Ratio Deco to have a relatively great emphasis on deep stops, this sits well with me in terms of choosing an approach to ascend planning at altitude, but:

As has been pointed out, I feel that it stands to reason the relative pressure drop exponentiates with approximation to the surface.
Hence, I add time to the shallow stops. Arbitrarily, yes. But the logic I'm working on, is that the slower ascend during the last portion of the decompression schedule, manages an increased relative pressure differential, along with some increase in slow tissue on-gassing during deeper stops.

Do I know that I'm "right"? Nope, but I clarify a logic and adjust an ascend framework from there.

However: In the face of all this, I still am opting for a solution or framework that I think is much more practical, over an algorithm that I know will be more precise (though I note that neither has evidence supporting how they work, as we discussed).

 

[lowviz]

...//... However: In the face of all this, I still am opting for a solution or framework that I think is much more practical, over an algorithm that I know will be more precise (though I note that neither has evidence supporting how they work, as we discussed).

An entirely reasonable approach. I would suggest that you buy a set of BSAC tables, as I did.

You could then compare various altitude tables to RD. I would find the altitude correction to RD to be most fascinating.

 

[lowviz]

@Dan_P :

One last offering, The approach that BSAC takes is pretty cool. You should look into it.

"Riding your Computer Up" vs. "Lite Deco"

 

[Edward3c]

@Dan_P :

One last offering, The approach that BSAC takes is pretty cool. You should look into it.

"Riding your Computer Up" vs. "Lite Deco"

BSAC Tables are available on our website, Here.