DIR and computers

[DSJ]

cnidae once bubbled...


Um, your Cobra does that. Like I said in my first post to this thread many computers give you ceilings, not stops. Once your Cobra goes into deco it will give you a 10' ceiling not a deep stop.



I found all Suunto computers to be terible with the deco depths. I've looked at my deco profiles and did'nt see the off gassing I tought I'd see.

I'll have to go back to the manual and try the simulation again, but I distinctly recall reading that the Cobra would give a deeper stop and gradually reduce the ceiling as offgassing was accomplished. The manual states that the time taken to get to the first stop could increase the total time required if performed too slowly. I also recall witnessing behavior that in the simulation mode. I've never come close to deco for real, so I can't prove that the simulation is also how it reacts for real, but I would think the manufacturer would be opening themselves up for a big liability if they stated falsehoods in the manual. You say you used the Sunto Cobra and saw the first stop was always at 10' regardless of the profile?

David

 

[Uncle Pug]

Stephen Ash once bubbled...
Pug...

I was just dropping shoes Stephen.

 

[David Evans]

Here are just a few flaws of using a computer (I use the Suunto Vyper and Stinger):

1. I had my Stinger on in the pool for a class two weeks ago. I managed to get down to a depth of 12 feet at the bottom of this particular pool. My Stinger didn't want me to fly for 12 hours afterwards.

2. If I do a dive to 20 feet for 1 minute, my computer wants me to stop for 3 minutes at 15 feet. If I dive to 90 feet for 20 minutes, my computer wants me to stop for 3 minutes at 15 feet.

3. On exactly the same profile: If I get into deco in Cancun, my computer figures I need the exact same deco stops as I do on the same profile in the Puget Sound (despite the fact that both computers know the water temperature).

Modern science on the subject shows that all three of these suppositions by the computer are incorrect.

 

[cnidae]

DSJ once bubbled...


I'll have to go back to the manual and try the simulation again, but I distinctly recall reading that the Cobra would give a deeper stop and gradually reduce the ceiling as offgassing was accomplished. The manual states that the time taken to get to the first stop could increase the total time required if performed too slowly. I also recall witnessing behavior that in the simulation mode. I've never come close to deco for real, so I can't prove that the simulation is also how it reacts for real, but I would think the manufacturer would be opening themselves up for a big liability if they stated falsehoods in the manual. You say you used the Sunto Cobra and saw the first stop was always at 10' regardless of the profile?

David

I've taken my Suunto's into deco more than I can count, not hard deco but minium deco. I've never seen anything but a 10' ceiling and a time before you can surface. With what we know to day this is not the way we want to conduct our deco. It's been proven deeper stops benifit our off gassing and from what I've seen, my Viper, Cobra, Vitek are in no way giving you correct info to benifit your body.

 

[Uncle Pug]

A week ago Shane forgot his Stinger at home. We use them for bottom timer/depth gauges.

He had a <brandname> hocky puck dive computer with the stuff that he keeps at my house so he used that instead.

Part way through the dive he was pointing to his hocky puck and indicating that it was not working.

OK... no problem.

We finished our dive as usual and then he told me what had happened. The hocky puck had gone into what it considered deco and decided not to assume any further responsibility for the dive. It decided to do this by not to giving any further information regarding time and would only show depth.

A bottom timer/depth gauge would not have had the liability heebeejeebees. Nor would a *computer* that could be operated in gauge mode.

Moral... carry a second timing device and don't carry a computer designed by coporate lawyers.

 

[Custer]

Uncle Pug once bubbled...

1. Folks keep missing this one. They can't conceive that there is something other than computer on your wrist or computer on your desk. I don't *cut tables*.

Not missing a thing, just wishing I was smarter and faster than a computer, too.

Uncle Pug once bubbled...
3. I know

Too bad your deco practices proscribe it.

 

[mgri]

David Evans once bubbled...
Here are just a few flaws of using a computer (I use the Suunto Vyper and Stinger):

1. I had my Stinger on in the pool for a class two weeks ago. I managed to get down to a depth of 12 feet at the bottom of this particular pool. My Stinger didn't want me to fly for 12 hours afterwards.

2. If I do a dive to 20 feet for 1 minute, my computer wants me to stop for 3 minutes at 15 feet. If I dive to 90 feet for 20 minutes, my computer wants me to stop for 3 minutes at 15 feet.

3. On exactly the same profile: If I get into deco in Cancun, my computer figures I need the exact same deco stops as I do on the same profile in the Puget Sound (despite the fact that both computers know the water temperature).

Modern science on the subject shows that all three of these suppositions by the computer are incorrect.

Excellent examples David, Thanks

 

[Uncle Pug]

Custer once bubbled...
Not missing a thing

Too bad your deco practices proscribe it.

1. Yes you are... you are missing what is being said about there being something other than either tables or computers. Now it may be intentional on your part... but that is something else altogether.

2. Saw tooth dive profiles are proscribed by common sense... and most agencies that I know of.

 

[DSJ]

cnidae once bubbled...


I've taken my Suunto's into deco more than I can count, not hard deco but minium deco. I've never seen anything but a 10' ceiling .

I believe you are correct about the behavior in minimum deco. The Cobra starts at 10' and lowers the ceiling as the deco obligation increases.

David

 

[String]

If I do a dive to 20 feet for 1 minute, my computer wants me to stop for 3 minutes at 15 feet. If I dive to 90 feet for 20 minutes, my computer wants me to stop for 3 minutes at 15 feet.

If you stay inside the NDLs all modern Suuntos build in an OPTIONAL 3 minute safety stop at roughly 5.5m. I cant see a problem with this. You dont have to follow it, it wont penalise you on further dives if you dont take its advice. Theres no harm in it giving those few minutes extra safety stop.

Any dive below 6m will generate an optional 3 minute safety stop.
If you go into decompression it adds this optional stop on the end as well - the key is the word optional. I cant see your problem with that.

3. On exactly the same profile: If I get into deco in Cancun, my computer figures I need the exact same deco stops as I do on the same profile in the Puget Sound (despite the fact that both computers know the water temperature).

Odd - the algorythm used in the modern suuntos is supposed to take into account water temperature. In any case there are 3 different personal settings that adjust the factors in in it - the manual for my vyper recommends altering it to P1 or P2 if cold. Basically YOU decide how much risk you take. Ive also not seen recreational tables that factor in temperature as a finite value in the calculation

Modern science on the subject shows that all three of these suppositions by the computer are incorrect. [/B]

Disagree with that. "Modern science" says nothing about a optional safety stop or you actively choosing your level of conservatism.