RGBM model: do you get locked out a lot?

[Charlie99]

Was this online or in print?

Typical report is
http://www.scubadiving.com/gear/dive_computers/crunching_the_numbers/0/

The key graph is http://dive.scubadiving.com/images/200408GR_computer_charts.gif . You will probably have to save it, then blow it up to read it.

The big differences show up shallow on the ascent. RGBM computers don't show much NDL time left at 40' towards the end of a dive. The Pelagic/Oceanic/PADI-DSAT model computers do. What they don't mention is that the Pelagic computers will be showing a tissue loading bargraph in the yellow zone at the point.

 

[Austin]

In print, it was one of last years issues, The tests were done in a pressure chamber. It simulated three dives, the first being the deepest. The times shown are taken at specific times throughout the dives. Here it is, click on the bottom right hand of the picture to enlarge it

 

[Austin]

Haha, nevermind, you beat me to it!

 

[chrisch]

The RGBM model is not conservative. It combines Haldane with bubble mechanics.

Computers that use RGBM do not lock out any more or less than any other. The use of RGBM has no relevence whatsoever to the lock out policy.

As others have said the Suunto range pay lipservice to RGBM but are no more likely to lock out than a pure Haldane/Buhlmann algorithm.

The question makes no sense.

Chris

 

[Austin]

Chris, what I'm pointing too is the differences in the algorithims. Because of the bubble mechanics, RGBM in some instances might subtract bottom time when you ascend from 60' to 40', where a pure haldane algorithim might add 20 minutes in this case, that is what i'm reffering to. I'm sorry, "locking out" maybe wasn't what i meant to focus on so much.

Look at the simulated dives in the link above.

 

[Kevin4diving]

I dive with a Suunto Vyper on my cosole and Suunto Gecco wrist mounted. They are more conservative. On repetitive dives they tend to want you to take an extended surface interval. I continue to dive with the gang but keep an eye on my no deco time. Most of the time my buddies are ready to end their dives before no deco becomes an issue. Especially with some dive operators who limit dives to 45 minutes (bummer). RGBM's don't like rapid accents and will penalize you heavily. Sometimes on a 6th day of repetitive diving I've noticed short no deco limits on second dives. I just stay to shallower depths to compensate for this. The main thing is dive a good profile. Then there shouldnt be any issues. I liked my Vyper (rgbm) so well, I bought a redundant Gecco (rgbm). I have never been locked out.

 

[cornfed]

Look at the simulated dives in the link above.

I'm having trouble making sense of the conclusions in that article. Haldane and RGBM are really different beasts. Trying to say one is more conservative when compared to the other because it adds time here or subtracts time there is a gross over simplification.

 

[nvert]

...from what I'm learning about my new D9 in diving with Nitrox...just play with the the RGBM % AND the Opp factors to increase or decrease the level of conservatism. I might be wrong here but if your mind KNOWS that it should work a certain way according to the charts and formulas, but your computer says it should be slower or more conservative, then just configure the variables to what you need. Again, it needs to be YOUR BRAIN driving the machine.

 

[TeddyDiver]

Thanks for the comments. I agree that there's no reason to exceed the limits in order for more time underwater or to rush out of the water.

It just seems that RGBM "similar" models that account for the tiny micro bubbles give you less dive time when you ascend to a certain level than the haldane or similar models would, because they don't account for "micro bubbles." I'd rather use a more liberal algorithim and stay out of the caution zone than to be locked out and not able to use the computer, but it sounds like that's not happening to many people.

I guess the underlying question that i'm trying to avoid, but hinting at nontheless, is whether the haldane and other algorithims are too liberal or whether the RGBM algorithim is too conservative, but I know that question isn't really able to be anwsered....

You didn't tell why your computer locked you out, but looks like you had too fast ascend/ not fulfilled required stops. Don't seek easy way out just do what that ¤%¤&¤ thing tells you to do.
Easy way out to get more bottom time is to set it to EAN Mode. Make sure we get to know how much when you get bends...

 

[bgi]

Used a Dacor Darwin Air. Got locked out during the first attempt at a deep dive in advanced class. Buddy was having trouble at 85 feet, so we went back up. There were three of us: Instructor, buddy, me. Here's what ticked me off. We descended rapidly and spent less than a minute at 80 feet. On the way back up, I stayed at the safety stop for 1-2 mins while the other two ascended. I said to myself, "This is stupid, I shouldn't be here alone. This is a SAFETY STOP. Not a DECO stop." So I went on up. LOCK OUT!! Ex-fraggin-scuse me? Lockout for that? I found the "ESA" simulation option and turned it on. No more safety stop violation lockouts. I reset the computer and did the remaining dives on tables and computer simultaneously.