Dependant on a computer...

[MHK]

pdoege once bubbled...
is more conservative than the SSI air dive tables at all depths except for 120 and 130 feet.

I imagine that most computers are pretty similar.

Does anyone have any actual evidence that computers are dangerously less conservative than tables?

Is this entire thread just a big mish-mash of FUD and elitism?

Peter

I think your words prove the point that many of us are trying to demonstrate. Take for example as you say:

The computer you use is more conservative then air tables... Most of us then say, why bother using one??? Most people who buy into the computer concept do so with the understanding that the computer can extend BT's. So it stands to reason that if they are actually more conservative then a table based dive, why spend $400??

If the idea is that they will track your NDL's for you, those that are resisting the computer trend point out that tracking your own NDL's, generally speaking, translates to a diver that turns his brain on underwater and pays attention to his dive.. Moreover, we like to point out that most computers use a set point that is based on the understanding that many diver's dive infrequently and as such may lack basic buoyancy skills, improper ascent rates, PFO's and the like. As such the set point isn't necessarily the most advantageous set point for you, but for a generic group of which you may not belong too.

By paying attention to your own diving, by recognizing that deep stops help efficiently off gas, by controling your ascent rate what you find is that your profile may very well be more efficient in terms of decompression stratagies, but the computer will penalize you nonetheless because of the algorithm used by the majority of the manufacturer's. As I noted earlier, some manufacturer's are catching up in terms of using the RGBM or VPM models, but most are still Buhlman based..

Hope that clears up where some of us are coming from..

Later

 

[Zagnut]

Scubachip once bubbled...

You can tell how well Your body is hydrated by Your urine. If it is a relatively clear color, You're well hyrdated (Supplements, including vitamins will affect urine color).

Another way to check your hydration level is to pinch the skin on the back of your hand and then pull it and let go. Your skin should pop back instantly. If it takes it a second to flatten back out against your hand, you need a drink.

 

[Charlie99]

MHK once bubbled...
By paying attention to your own diving, by recognizing that deep stops help efficiently off gas, by controling your ascent rate what you find is that your profile may very well be more efficient in terms of decompression stratagies, but the computer will penalize you nonetheless because of the algorithm used by the majority of the manufacturer's. As I noted earlier, some manufacturer's are catching up in terms of using the RGBM or VPM models, but most are still Buhlman based..

Is it bad practice to use Buhlman-based deco programs such as DecoPlanner to plan dives, since these also penalize you for slow ascents and deep stops?

Charlie

 

[wreckchick]

I dive a relatively liberal computer, Aeris Atmos 2, and I use it to monitor depth, time, temperature, ascent rate, and NDL. Since I'm a newish diver I find that the ascent rate indicator is probably the one thing that I find most useful about having it with me.

Generally, my non-led dives are shallow so NDL times aren't as important but my ascent rate and depth monitoring are. Now I know that with practice I'll be able to better control ascent rate without an aid, but in the meantime, as many of you have pointed out, rapid ascents are one of the prime causes for DCS and I'd like to avoid it if possible.

The ability of the computer to give me precise information on depth is useful for buoyancy control, time at depth is obviously a key to good dive management, and NDL is good if the dive plan changes underwater which it sometimes does in the realm of recreational diving. If there's nothing good to look at at 60', why not go up to 40' and poke around there? Obviously the NDL changes and a computer can help you make on the fly changes if that's appropriate. As long as what your computer says makes sense and you and your buddy are seeing similar readings, I see no reason to limit the dive to the plan at 60' when you can get a few extra minutes at 40'.

If those of you with more experience want to do on the fly calculations in your head, fine with me; if you want to strictly plan by tables and not alter the plan in any way, that's fine with me too. I can't do the calculations in my head, I don't have a good enough sense of what's going on to make that work. As for going purely off the tables and a strict dive plan, do it if it works for you, I don't see any reason to do that if I have a tool that allows me to do differently.

my name is Rachel.... and I love my computer

P.S. On led dives I pay careful attention to the briefing and run the plan through the BS meter and my computer and the tables before I go with it. I don't just blindly follow along.

 

[MHK]

Charlie99 once bubbled...
Is it bad practice to use Buhlman-based deco programs such as DecoPlanner to plan dives, since these also penalize you for slow ascents and deep stops?

Charlie

I was actually referring more to the in-water computers. I don't think most use Deco Planner for recreational depths or dives.. As a tool for planning Decompression dives Deco Plan works well, and you have the ability to adjust the gradients and plot your deco curve.. To me the graphics and looking at the shapes of the curve is one of DecoPlanner better features.. THere is a few tricks on decoplan that help get around the deep stop issue and Buhlman based models ;-)

Later

 

[Uncle Pug]

biscuit7 once bubbled...
my name is Rachel.... and I love my computer
*******************
I don't just blindly follow along.

I'm sure Computer loves you too. Such feelings cannot be easily discounted... and yet... perhaps there is another suitor who will not be so demanding and give some control of the dive back to you... so you won't have to blindly follow along diving by your computer's dictates.

As for the rate of ascent meter... by the time your computer tells you that you are ascending too fast... it is too late... you are already ascending to fast. And by the time it teases you with the information that your are now descending... it is too late... you have already lost altitude.

A better way is to use the stuff. Not the stuff we talked about previously... the other stuff... the stuff that you can see floating in the water... use it as a reference... a visual cue.

And then there is the other other stuff... your ears know all about this stuff... and then there is the other other other stuff... the stuff that your skin pays attention too.

And of course finally there is the stuff that we talked about... but it is such a quiet niggle that you almost need to have your eyes closed to see it.

All of this stuff can help you with your ascent but it gets pushed back on the attention queue if you are rivited to your computer's ascent rate indicator.

 

[wreckchick]

I know what you mean, and slowly I'm starting to get it. My last dive I would only check the computer to double check my head. I'm getting better, but I'm not anywhere near where I want to be.

I'll admit to staring at my ascent rate on my first bunch of dives. Then I realized I was never going to get it unless I looked out and around me. Now in local stuff the visual reference is gone and I'm starting to pick up on the other stuff.

One day I'll be able to do it with my eyes closed, but not just yet

R

 

[Blue Space]

Have you ever used a computer?

 

[Braunbehrens]

Uncle Pug once bubbled...

As for the rate of ascent meter... by the time your computer tells you that you are ascending too fast... it is too late... you are already ascending to fast.

Either that, or you're diving in big swell ;-)

I was diving in fairly big swell about a year ago, and the computer kept beeping at me. It was really annoying, but there wasn't anything I could do about it. You know you have a problem when you need to clear your ears even though you haven't moved in relation to the bottom

Seriously though, excellent post, Uncle Pug!

 

[pdoege]

NT