What makes us think we can trust any of them

[Uncle Pug]

But it illustrates a point.

No.. it doesn't illustrate a point.. it only confuses the point.

You asked where does one learn the skill to shape the curve... by paying attention to people who know how to do it. Snowbear even included pictures for you. Now all you have to do is make your dives look like that. If you can control your depth without bouncing along the bottom for the whole dive you can do it.

This isn't hard. All it takes is a little enlightenment. That is what a few of us are trying to do here.

 

[Uncle Pug]

At least the technique that UP is talking about won't get explained to you.

Let me just try to give you a rough sketch of something that you could apply to most of your dives. It's not quite what UP is talking about but it's easy enough to understand and is probably a big improvement over what you were already taught. Keep in mind that this is the Rob Turner method and has nothing at all to do with what UP is talking about despite certain similarities.

The first and most important thing is that the graph of your dive profile should look a little like a big check-mark.

Gee.... I wonder where you got that?
Uncle Pug talks about the check mark.... two and half years ago.
And a month later...
explains how to do it.

I should be flattered I suppose... :05:

 

[Web Monkey]

Now I'm a bit confused. I realize that all tables are not the same, but I have a hard time seeing that a table that measures based on rounding up your deepest depth, and rounding up your time, could be more liberal than a computer that calculates time at depth.

If you dive a square profile using a computer and a table, there's no guarantee which one will be more conservative.

For example, on a 40 minute dive, I spend 10 minutes at 75 feet, glide up to 50 feet, spend a while there, move up to 30 feet, spend some more time there, finish with a 5 minute stop at 15 feet and get out. Using the table, I calculate my PG using 75 feet for 40 minutes. No I definately didn't stay there for 40 minutes, but according to the table, I did. My PG based on what my computer would tell me, or the wheel if I could figure that out one day , would be much more liberal. How can it not be?!?

If you dive the computer on a multi-level profile and calculate the same profile using tables (difficult unless you have detailed time and depth information), there still no guarantee which one is more conservative.

If you dive the comptuer on a multi-level profile, but calculate it as a square profile using tables, then yes, the tables will probably be more conservative because you're not plottting your actual dive.

My first quote about a computer failing was really to cover any failure, for example, your example about the shallow nitrox dive. Clearly the computer failed. Should you rely on it? Do you really trust it after it told you that there was a long decompression stop? Did you not perform the decompression stop just to be safe, and then check it out some other way? I think I would check with the manufacturer if something like that popped up on my screen.

It was my buddy's computer. I don't know what she finally did with it, however since it was clearly broken or misconfigured, we didn't see much point in doing what it said.

My point ws that you should have an idea what's reasonable so that if you dive with a computer and it says something bizzare you can recognise it.

And also, I think it's good practice to use the tables, just to keep their use fresh in your mind.

Absolutely.

Terry

 

[Diver0001]

Gee.... I wonder where you got that?
Uncle Pug talks about the check mark.... two and half years ago.
And a month later...
explains how to do it.

I should be flattered I suppose... :05:

I know, I know. Despite appearances I actually do retain some things. It just depends on whose talking...

Should I have referenced you?

R..

 

[Uncle Pug]

Should I have referenced you?

No, not at all... I don't need the recognition... the emulation is more than sufficient reward.

Imitation confirms that the message has been received and is being assimilated.

 

[Diver0001]

No, not at all... I don't need the recognition... the emulation is more than sufficient reward.

Imitation confirms that the message has been received and is being assimilated.

Yes, I'm being assimilated.... Actually, it's not the only way you've influenced me.

I would have referenced you but I thought I was going to mangle some important detail and piss you off.

R..

 

[Uncle Pug]

I would have referenced you but I thought I was going to mangle some important detail and piss you off.

I'm not that easy to PO.

The details only cloud the big picture:

1) shape the ascent curve to look like a check mark (which is just basically reversing the shape of the ongassing curve) and 2) leave the bottom with enough gas to do the tail.

You got those two in... somewhere it all that.

 

[Potapko]

Snowbear even included pictures for you.

Sorry UP, But I responded to your post before reading Snowbears

 

[TSandM]

Hooray, hooray, hooray for this thread! And THANK YOU to Rob. I have read both of UPs prior threads, Snowbear's posts, and Doppler's "shape of the curve" articles on TDS, and still felt fuzzy about all this . . . somehow Rob's post blew the clouds away. Goes to show you that sometimes you have to hear the same thing put a number of different ways before it connects.

GREAT THREAD.

 

[Potapko]

Ok,
For the sake of provocation perhaps
I am a fairly new diver with only around 70 dives logged. I have never been overly tired after diving. even after doing a three dive day including the first to nearly 100 ft. For the sake of this discussion, Why would someone take so much time to ascend when accepted opinion says 30 ft/min is no problem, even from depth? Arguing that even the 15 ft safety stop is optional on a ndl rec dive.

Ok, let me put it this way, other than perhaps the last 10 feet, what is wrong with the first profile in Snowbear's post?

Please take this the right way. I am trying to learn but also need to be convinced.