Suunto Vyper **SERIOUS BUG** in CNS O2 computation

[cornfed]

Genesis once bubbled...

The ugly part of this from my perspective is that even the "Kool Aid" folks who promote this, and even who represent this agency, won't publish their claimed methods.

I have a written description of the method. It came from one of the "kool aid" folks.

NAUI/SSI/PADI/YMCA/etc all publish THEIR claimed methods. They put their corporate arse on the line by doing so, in that even if you couldn't sue them their reputation is attached to their claimed "safe methods" (ok, "safer" methods)

Call one of these guys and ask them for some nitrox tables or better yet trimix. Tell them you don't want to take their classes you just want the end result. Tell them you're just interested in evaluating there methods. Let me know how that conversation goes.

GUE won't even go that far - they refuse to put their claimed methods out there where you can actually look at and evaluate them, test against software like VPlan and computer model simulations, or against actual runtime profiles, and attempt to come to a reasoned conclusion as to their relative safety and applicability to you as a diver.

I understand your frustration but I'm having a hard time sympathizing. I believe the information you want is out there; it's just not as wild disseminated as you would like.

Some random "whacko" posting a method that he claims hasn't bent him (yet) isn't good enough for me.... and I suspect its not good enough for you either

You're right, it isn't. But that isn't what we're talking about now is it?

Cornfed

 

[Genesis]

but the "Rule of 120" with a modification for repetitive dives which is very simple ignores some very real and well-understood physiological issues.

This isn't the right thread for that discussion though......

 

[jamiei]

I just got an email from Suunto that states that the Cobra and Vyper do in fact use the exact same software. The only difference is that the cobra is air integrated and calculates air time... I was also told that no such email regarding this situation has been sent to them.

This email was from the US suunto importer, aqualung... and a response from Finland is supposedly on its way.

 

[cornfed]

Keep us posted...

 

[Aquamaniac]

Genesis once bubbled...
but the "Rule of 120" with a modification for repetitive dives which is very simple ignores some very real and well-understood physiological issues.

This isn't the right thread for that discussion though......

I agree with both points.

The one comment I would like to add though, is the amount of research and development that goes into Suunto's algorythms.
I am quite ceratin that its all based on theories, with some padding and conservitism.
However, the GUE and VPM "tables" for example are a VERY well tested model.
How many of Suuntos "Test Pilots" do deep exploration followed up with Doppler sampling by Duke university?

Genesis once bubbled...
GUE won't even go that far - they refuse to put their claimed methods out there where you can actually look at and evaluate them, test against software like VPlan and computer model simulations, or against actual runtime profiles, and attempt to come to a reasoned conclusion as to their relative safety and applicability to you as a diver.

Well, thats actually quite far from the truth, allow me to quote GUE.

GUE once bubbled...
GUE is at the forefront of decompression software development, with a proven foundation of real-world testing by diving's most active researchers and explorers. Our PC based DecoPlanner is already in use by divers around the world in both recreational and aggressive technical diving situations, including world record cave diving explorations in the Woodville Karst Plain and deep sea documentation of the Britannic shipwreck.

 

[Former FLL Now MSP Diver]

Aquamaniac once bubbled...
The one comment I would like to add though, is the amount of research and development that goes into Suunto's algorythms.
I am quite ceratin that its all based on theories, with some padding and conservitism.

I wouldn't be so certain if I were you.

From the manual

6.2. REDUCED GRADIENT BUBBLE MODEL,
SUUNTO RGBM

The Reduced Gradient Bubble Model (RGBM) is a modern algorithm for tracking both dissolved and free gas in the tissues of divers performing a wide variety of maneuvers. Unlike the classical Haldane models, the RGBM can address a number of circumstances outside the range of just dissolved gas
models by:
• monitoring continuous multiday diving
• tracking closely spaced repetitive diving
• accounting for diving deeper than previous dive
• regulating rapid ascents with high degrees of Doppler bubble
formation
• incorporating consistency with real physical laws for gas kinetics
• taking a modern approach to a difficult problem.

The SUUNTO RGBM algorithm is developed in co-operation with SUUNTO and Bruce R. Wienke. It is based both on laboratory experiments and diving data.



The research and testing that went into RGBM models is very well known, as is the work of Dr, Bruce R. Wienke, PhD. You can read all about the development and testing in a number of different papers, and in his book Basic Diving Physics and Applications.

Marc

 

[Charlie99]

Aquamaniac once bubbled...
Well, thats actually quite far from the truth, allow me to quote GUE.: GUE is at the forefront of decompression software development, with a proven foundation of real-world testing by diving's most active researchers and explorers. Our PC based DecoPlanner is already in use by divers around the world in both recreational and aggressive technical diving situations, including world record cave diving explorations in the Woodville Karst Plain and deep sea documentation of the Britannic shipwreck."

Interesting. The only DecoPlanner I have seen is PURE HALDANIAN DISSOLVED GAS MODEL!

I believe WKPP has used RGBM models for planning their dives. Perhaps DecoPlanner might have been used for some of the support dive planning, but in any case, it is a basic Buhlmann model, with gradient factors, much like GAP and many other predecessors.

 

[Former FLL Now MSP Diver]

Charlie99 once bubbled...
Interesting. The only DecoPlanner I have seen is PURE HALDANIAN DISSOLVED GAS MODEL!

I believe WKPP has used RGBM models for planning their dives. Perhaps DecoPlanner might have been used for some of the support dive planning, but in any case, it is a basic Buhlmann model, with gradient factors, much like GAP and many other predecessors.

You are absolutely correct! From the DPlan users guide:

DPlan computes compartment off-gassing during a surface interval using a simple Haldane (constant-depth) formula. It's no different than a segment of the dive, except that it's 79% N2 breathed at the surface pressure (as defined below in the Altitude section).

There is definitely more to conducting repetitive dives than the dissolved gas models can explain. Bubble models like VPM and RGBM may do a better job with this.

Notice the statement that VPM and RGBM may do a better job. I wonder why they decided to use the much more conservative Haldane models in their software?

Marc

 

[Charlie99]

FLL Diver once bubbled...
Notice the statement that VPM and RGBM may do a better job. I wonder why they decided to use the much more conservative Haldane models in their software?

You can change parameters to make any of the models more or less conservative.

I look upon VPM and RGBM as extensions and refinements, much as relativistic mechanics is an extension of Newtonian mechanics.

In a similar way, though, although Newtonian physics may not be entirely correct, there is a large range of common real world problems for which they are perfectly adequate.

 

[Genesis]

I just got an email from Suunto that states that the Cobra and Vyper do in fact use the exact same software. The only difference is that the cobra is air integrated and calculates air time... I was also told that no such email regarding this situation has been sent to them.

This email was from the US suunto importer, aqualung... and a response from Finland is supposedly on its way.

My message to Suunto was sent directly through www.suunto.fi, via their web page.

It was not sent to Aqualung - they wouldn't know what was going on with the software, as they did not develop it.

No surprise they'd not know about my email, as it wasn't sent to them.

Still no response from Suunto to my inquiry as of this evening.