Recreational RGBM vs. Technical RGBM

[MB NZ]

So what is happening when my Zoop shows a ceiling of 7m?

to be honest, no idea! does the zoop do deep stops?

---------- Post added October 3rd, 2014 at 10:26 PM ----------

[/COLOR]As I get older though I realise my limitations and have no intention to get bent, so perhaps the assumed conservatism of Suunto's RGBM is not a bad thing, an extra minute in the water is better than a day in a chamber.

agree with the assumed bit, compare P-2 to generic dive planning software and one might be surprised. too rich for my blood. i'll stick with P-1.

 

[KenGordon]

to be honest, no idea! does the zoop do deep stops?

---------- Post added October 3rd, 2014 at 10:26 PM ----------



agree with the assumed bit, compare P-2 to generic dive planning software and one might be surprised. too rich for my blood. i'll stick with P-1.

The Zoop doesn't do deep stops, the 7m ceiling reflects the saturation from a deep dive. I think it does credit being above the 'floor' but also that figuring that for sure might require some experimentation.

 

[gekodivebali]

The issue i have about Suunto computers for Technical diving is the lack of transparency when it comes to the algorithm or the penalties it applies.
One example is the use of ceiling as optimal deco depth. This is not the case in reality since ceiling, or deviating upwards from it, implies a risk to the diver's safety through increased tissue tension. In practice, a diver may be better off to stay one or more meters below the ceiling (eg due to swell) and all Suunto computers penalise you for this.
This is even true on a Vyper Air using pure O2, although it is nonsensical from a physiological point of view. Understand the Oxygen Window and you quickly realise there is no difference between a last stop at 5m or 3m on O2 from a deco pov.
Another exemple is Suunto's implementation of nitrox usage in its computers. If you set a PO2 of 1.4, computers will lock you to 1.38b or even 1.37b. Why would this be relevant to a Tec diver? A Tec diver may end up having to set his computer on a 1.5b setting in order to achieve his MOD at 1.4b. Similarly, who has ever heard of OLF% and where is ample literature available as to what it really means?
This type of strange behavior from Suunto computers is the reason why I would not use them for deco diving and advise others to do the same. If I could read the formulae involved and could find out why I am penalized for doing some things that change nothing from a physiological pov, then I may be able to reconsider this. I know this will not be the case since RGBM and Suunto's iteration of it is proprietary and cannot be independently verified.

That being said, I am not here to bash Suunto. They have great computers for your average diver who seeks conservatism and does not want to bother with understanding the inner workings of algorithms or deco theory.

 

[SoFloDSO]

I find it interesting that most of us using the Helo2 seem to have gone the same route using a Vyper as backup. After encountering the same problem myself, I finally took the leap and purchased a Dx to use concurrently with the Helo2. And, wait for it...same problem. Several minutes difference with the Helo2 being the more conservative. The Helo2 uses a RGBM model which goes by the saw tooth philosophy of deco with fixed depth deco stops. The Dx uses a RGBM Fused model with takes into account actually ascending slow enough to ascend continuously as the stop. However, with Suunto, one of the problems you get is that some models allow you to turn off the deep stops and some don't. I use Helo2's, Vyper Air, Cobra 3, Cobra 2 and Dx for various applications and they all use a slightly different algorithms. Best approach as you stated, go with the most conservative. If you don't, one of your computers is going to Err anyway.