28 Hours of No Fly Time?

[seeker242]

A common misunderstanding of what a theory is.

What computer actually measures deco stress? And how does it do it?

 

[Storker]

Suunto is known to use it's own propitiatory algorithm, which is also known to be extraordinarily conservative.

Is it now? Yes, it penalizes a bit extra you for blown safety stops and fast ascents. But try planning two consecutive NDL dives on the Suunto Dive Planner, the PADI RDP, USN tables and BSAC-88. I've done that, as well as on our national tables. Typical SI, about two hours.

If you do that, you'll see that:

• Suunto and PADI agree on NDL within a minute or two for the first dive, both for square profile dives and simple multilevel dives
• Suunto and PADI agree on NDL within a minute or two for the second dive, at least for square profile dives.
• USN (and, IIRC, BSAC-88) are more liberal than both the RDP and Suunto for dive number 1, but much more conservative for dive number two.

So that often perpetrated myth about Suunto's "excessive" conservatism is, for many types of diving, just that. A myth.

 

[Storker]

A common misunderstanding of what a theory is.

Not just common, but fundamentally wrong.

What computer actually measures deco stress? And how does it do it?

It doesn't. But that doesn't make the algorithm - nor the model the algorithm is built on - a "guess". A model is based on data and has a certain amount of predictive power. A theory - as in "scientific theory" - is a lot more than that. It's built on repeated experiments, it's a representation of the best of our knowledge, can basically explain what's happening in a coherent way and has a lot of predictive power. You know, like Newton's theory of gravity, Einstein's theory of relativity or Darwin's theory of evolution.

Pretty far from "a guess".

 

[seeker242]

A model is based on data and has a certain amount of predictive power. A theory - as in "scientific theory" - is a lot more than that. It's built on repeated experiments, it's a representation of the best of our knowledge, can basically explain what's happening in a coherent way and has a lot of predictive power

So you are saying that computers that show a maximum 24 hr fly time are unsafe? Where is your data to support this? Answer, you don't have any.

Not just common, but fundamentally wrong.
It doesn't. But that doesn't make the algorithm - nor the model the algorithm is built on - a "guess". A model is based on data and has a certain amount of predictive power. A theory - as in "scientific theory" - is a lot more than that. It's built on repeated experiments, it's a representation of the best of our knowledge, can basically explain what's happening in a coherent way and has a lot of predictive power. You know, like Newton's theory of gravity, Einstein's theory of relativity or Darwin's theory of evolution.

Pretty far from "a guess".

Also, completely irrelevant when you are trying to claim that that 24 hours of fly time is unsafe. DAN and PADI both disagree. You are saying you know better than them, that's highly unlikely as well as completely ridiculous.

 

[jonhall]

It’s a theory, aka a guess,

A common misunderstanding of what a theory is.

So it is a hypothesis!

Until I started using my Suunto Cobra (first and only computer) I didn't know how much I was doing wrong when diving without a computer. Although I know it has made me a safer diver - I just recently remarked to my buddy that I never hear my computer beeping or flashing numbers at me like it did the first couple of years I had it - there are times I question what it tells me to do based on previous dives with similar profiles.

 

[tursiops]

What computer actually measures deco stress? And how does it do it?

See post #63.

 

[Storker]

So you are saying that computers that show a maximum 24 hr fly time are unsafe?

No. Are you strawmanning, or didn't you read my post?

you are trying to claim that that 24 hours of fly time is unsafe.

I'll type this very slowly: I. Did. Not.

So it is a hypothesis!

It's neither. It's an algorithm built on a model. Not as strong as a theory, but a heck of a lot better than a guess.

 

[seeker242]

See post #63.

Which is not an actual measurement, so post 63 isn't it. Even though all that is completely irrelevant as to whether or not 24 hrs is unsafe.

 

[seeker242]

No. Are you strawmanning, or didn't you read my post?


I'll type this very slowly: I. Did. Not.

Are you straw manning my post? Or didn't you read my post? Here's a refresher.

Hard to argue that it would be unsafe when tons of other computers would say 24

So, perhaps you should stop taking it out of that context. The question is: Is 24 hr unsafe? The answer is, no it isn't. Unless of course you have some empirical data to back that up, which you don't. It is not a strawman of your post, it's simply a keeping of the original context.

 

[Storker]

Are you straw manning my post? Or didn't you read my post? Here's a refresher.

You argued against a claim that 24 hours was unsafe, and you attributed that claim to me. Arguing against a claim that hasn't been made - like you did, and I quoted - is a schoolbook example of the straw man fallacy.

The question is: Is 24 hr unsafe? The answer is, no it isn't.

No, the answer is, it depends, but most probably not for most of us. 48 hours is even less unsafe, but probably even less unsafe than most of us need for feeling comfortable.