Mares Puck Deep Stops

[flyingm]

I was wondering if anyone has info regarding the trigger points of the deepstops for the RGBM model. I dove a few days recently in Coz and never had a deep stop recommended, albeit pretty tame profiles. According to the manual you need to be close to NDLs to trigger it (no mention of how close). But, do ascent rate violations, sawtooth, etc also affect the deep stop trigger? I kind of was hoping for a way to set deep stops for all dives but I guess I will continue to use the rule of 1/2.
Anyone using this computer get a deep stop and if so what was the profile?

Thanks

 

[Charlie99]

If you were doing the typical profiles I've seen in Cozumel before, then you were doing multilevel dives where you go deep for a while, then shallower. You probably didn't see a deep stop requirement because the shallow portion later in the dive is effectively a deep stop.

Another point to look at is that the models don't call for deep stops until you have required decompression stops. The computer can crank one in for any arbitrary condition, but the model itself won't be saying that it is needed. That's what the manual is really saying when it says that you will see a deep stop only if you are close to NDL.

You can always add deep stops yourself. This is very much like adding a safety stop on a dive without mandatory decompression stops.

The other thing to look at is whether or not your computer is actually running an RGBM model. If you have one of the Mares computers that are like the Suuntos, then the model the computer is running is actually a dissolved gas neo-Haldanian (aka Bulhman) model. In other words, it is NOT a bubble model or dual phase model, but is a plain old vanilla dissolved gas model not that much different (other than the specific limits) than the Workmann/US Navy model. To emulate true RGBM, the M-value limits of the dissolved gas model are reduced in response to things like short surface intervals, reverse profiles, sawtooth profiles, and rapid ascent.

If you manual says the model is "Mares-RGBM" or something similar, then it isn't really RGBM.

 

[flyingm]

I don't know if this will help but I did run across this link:

http://www.rgbm.mares.com/html/eng/rgbm/index.asp?lang=eng

and also the Suunto rgbm:

http://www.dive-tech.co.uk/resources/suunto-rgbm.pdf

and yes, the model says "mares-wienke rgbm"

***************Just ran across this http://www.scubaboard.com/forums/mares-just-add-water/181433-rgbm-deep-stop.html and I think it answers my rgbm ?'s but I just wish there were more specifics for the deep stops from the manual or Mares

 

[Charlie99]

the Mares-RGBM is a psuedo-RGBM, just lke the Suunto RGBM. I do believe Mares does make a computer with a full RGBM model, but they are relatively expensive.

Deep stops are not something separate from the model. You get deep stops by setting model limits, particularly on the faster compartments, low enough that you have a deep mandatory stop. So you won't see deep stops in either a real RGBM model or the psuedo-RGBM models until you are relatively heavily loaded. This is also true of the well documented, open source dual phase (bubble) model, VPM, which is used in the popular deco program V-Planner and is also used in at least one high end computer.

Was I right in guessing that your Cozumel dives were mostly multilevel? I remember a lot of dives there where the profile was something like 80' for 15 minutes then up to 50' for another 15 minutes or so, and then on into the shallows for the rest of the dive. With such a profile, the 50' and 30' portions bring you back up to the surface with a minimum of bubbling.

 

[flyingm]

Thanks for the info, I ran across one of your previous posts on the subject.

Yes, my coz dives were very multi-level. In essence I was decompressing for 1/2 my dive! (almost)

Thanks again

 

[potato cod]

Good question, Flyingm! I was just wondering about this myself. The manual doesn't indicate that you can set a deep stop that is essentially the rule of 1/2, which would be nice. Certainly the computer between my ears can handle this anyway, but the reminder and timer would be nice.

Zak, any input? Can we set the Puck up to give us a deep stop a la the rule of half? If not, any input into the triggers? Thanks!

 

[flyingm]

Zak, any input? Can we set the Puck up to give us a deep stop a la the rule of half? If not, any input into the triggers? Thanks!

Well, I'm positive that I can't force it to give me a deep stop unless it deems it necessary so, I guess the only real way to find out is to make the personal factors setting really conservative and then dive, dive, dive. I'm sure that at a P2 I could get closer to the ndl's. But you're right I think I'll just continue to multi-level dive or build my own stops. I've even started to add a couple stops in addition to the deep stop. ie. on a square 90 ft dive I'll do a minute at 45 and 30 and 3 mins at 15.

You know it almost looks like we are starting to see non-decompression, decompression diving!

 

[CODMAN]

If I remember correctly from my M2 manual, the mares computers only give you an optional deep stop at 60 feet (you don't get locked out if you don't do it) if you get to within 1 minute of your Nodeco time past a certain depth (can't remember by heart). I've only had it kick in once or twice; usually I'm off the bottom way before 1 minute left!

So definetly, no you can't set these deep stops yourself. If you want to see what it's like, go into simulator mode and give yourself a deep dive where you lift off the bottom with less than 1 minute left! You should get the deep stop prompt!

Cheers!

 

[flyingm]

actually, the deep stop depth is a calculation. According to the manual, after needing a deep stop it says that you should double check the recommended depth and time b/c it may change. I think the puck stops are different than the M2.

 

[CODMAN]

actually, the deep stop depth is a calculation. According to the manual, after needing a deep stop it says that you should double check the recommended depth and time b/c it may change. I think the puck stops are different than the M2.

Actually Flying, I re-checked the M2 manual and it,s just as you said: deep stop depth is calculated... Sorry about my fading memory! getting old ya know...