bgi, IMO, its called a safetystop for a reason...if my comp tells me to spend an "extra" 3 minutes at a safetystop then thats what I´ll do...I may not always need it but those three mins will VERY rarely mean much in the big picture anyway so why not zone out for 3 minutes? If you´re in such a hurry to get out of the water, then why are you diving in the first place?
RGBM model: do you get locked out a lot?
- Thread starter Austin
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Austin:
RGBM typically limits no deco time to minimize the size of the bubbles so usually any computer that uses any form of RGBM will usually have a shorter no stop time.. You are definately penalized for reverse profiles and for fast ascents becaise this will create more bubbles..
Now start doing dives WITH REQUIRED deco... if you are using the right gases and a full up RGBM model your deco time will be typically less than a haldane model and in somecases substantially less.
You cant just use a flat statement like this model is more conservative vs that model, you have to be specific.. Also the gas used really changes the efficiency of the model... Anyone doing dives with helium added, really sees a difference between a haldane and RGBM model.
You also have to take into consideration that computers and tables will treat you differently.. tablkes generally allow a much greater so stop time than computers becasue in general they are designed for square profiles and have lots of padding inhertly as part of the table.. A computer doesrealtime calcs and you need to enforce stricter limits because you can get micu closer to that theorectical limit...
For example the RDP allows 20 minutes at 100fsw, most computer models alow somewhere between 15 an 19 minutes (16 and 17 seem to be the most common) (they use a different set of surfacing limits) the middle compartments usually have more restrictive limits in the computers..
for example for deco tables (ndl tables allow greater limits) zhl-16b is the usual limits used,but computers generally use zhl-16c (which has the limits modified for additional safety) and get additional modifications based on the individual implementation.
You should never use your buddies dc as a confirmation of your own required time, unless you did EXACTLY the same dive as him/her (pretty hard to do), his liits are only valid for him/her..
grazie42:
Absolutely, it's a SAFETY stop. Not a REQUIRED stop. I was only at depth for 1 minute.
We were diving as a trio. What's wrong with diving with trios? They tend to become a buddy pair and a solo. That's why we don't dive trios, right? I could:
A) Solo dive on an adv class checkout dive. That would be impressive, no?
B) Stay with my buddies, as I was instructed to do.
Additionally, as I said, my buddy was having trouble. What if the instructor needed assistance with him and I'm down there doing a safety stop?
In the material I've read and throughout instruction, safety stops are not required. They are what we call them. This computer thinks differently. That's the point. I'd like to see any evidence of anyone getting DCS under these circumstances. I just don't believe there's any historical basis for this "feature" with this dive profile. While I'm sure Mares put this lockout in for a good reason, I believe they went overboard on the parameters.
Your response implies that I don't plan to do safety stops in the future. Not at all. However, if I have a good reason (no matter what the reason is) to skip a safety stop after being down for one lousy minute, I do NOT want a 24hr computer lockout on an expensive vacation.
Sorry, it just doesn't seem like you read or understood the original post. Maybe I didn't make it clear.
bgi:
In an RGBM model the deep stops ARE NOT safety stops, they are required to keep the model valid. If it wants you to stop your ascent you have to if you wish to use your computer for the next 24-48 hours...
No deco limits fro tables are calculated using tdifferent parameters tan a DC.. A DC actually builds the profiles based on a decompression model limit..
see my prior post.. or beter yet read Erik bakers paper on m-values..
Never had a RGBM lockout, but then again I follow the computer's directions. Three minutes versus forty eight hours seems a small price to pay, whether you're on an expensive dive vacation or just hanging out in the lake. The stop could be totally unnecessary. However the alternative is to dive tables and never get locked out.
Just an aside, my last 85' dive on air had no safety obligation because of the profile. We spent about 12 minutes at depth then ascended in graduated steps over another 20 minute period. At 15' we did a pocket safety stop by lazily following the wall back to the anchor line before ascending - no worries. My Vytec still registered double digits of no deco time remaining and no safety obligation recommended. For what it's worth.
Just an aside, my last 85' dive on air had no safety obligation because of the profile. We spent about 12 minutes at depth then ascended in graduated steps over another 20 minute period. At 15' we did a pocket safety stop by lazily following the wall back to the anchor line before ascending - no worries. My Vytec still registered double digits of no deco time remaining and no safety obligation recommended. For what it's worth.
WarmGoingCold
Contributor
cannon_guy:
I had the same experience with my cobra. The safety stop by the way is one of my favorite parts of a dive(in warm water), so if the comp wants me to sit at 15-18 feet for an extra 3-6 minutes then so be it. If you were with me you would see a big smile behind my reg as I was floating along enjoying the scenery below.
There are alot of "anti-conservative" folks on the board when it comes to dive computers, so the best thing to do as always is listen to both sides opinions and formulate your own opinion on how conservative you want your computer to be. I am a new diver(60+ dives now) but I have learned that the ocean is a beautifull but rutheless place, and I would rather be safe than sorry.
robo
Registered
Those safety stops, with a bag of bloody fish attached, gives me the creeps.
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