Help with Buhlmann ZHL-16c GF

[scubadada]

Can someone direct me to where Shearwater says what its recreational GFs are?

In their rec manual, low conservatism https://www.shearwater.com/wp-content/uploads/2014/03/PetrelManual_Nitrox_Rec_Mode_DocRevA.pdf

---------- Post added September 29th, 2015 at 11:22 AM ----------

I hope this was not meant for me! My question was not about GFs, which I actually think I understand pretty well.
My question was about the alleged statement from Shearwater that their recreational mode is 45/95, and that it matches PADI/NOAA tables.

I understand it reasonably well also, looking for a more advanced reply

---------- Post added September 29th, 2015 at 11:23 AM ----------

Not if you ask 10 people who know what they're talking about.

Are you 1 of the 10, give me some useful information

 

[CptTightPants21]

The article on Andy's site was not useful beyond my current understanding. I have the previous edition of Deco for Divers and have read it several times, is the new edition significantly different/updated?

If you have read deco for divers and understand the topic then I am not sure what your question is.

GF are meant to customizable depending on personal preference. Some times a diver wants to be more conservative/aggressive with his dive profile other times he might be trying to match the non-Bulhmann algorithm another one of his dive computers is using.

I think you are seeing a lot of computers running the Bulhmann with GF because the Bulhmann is considered the "standard" deco model and when you combine GF the diver can have it act like the deep stop/bubble models if they so wish.

 

[scubadada]

I am sure the links posted above will cover this and answer your question, but 100/100 is the Bulhmann deco algorithm. The gradient facts are percentages of the Bulhmann formula. Less than 100% gradient factors are more conservative and gradient factors greater than 100% are less conservative than the standard Bulhmann.

Sorry, get some more dives, experience, and knowledge

---------- Post added September 29th, 2015 at 11:27 AM ----------

If you have read deco for divers and understand the topic then I am not sure what your question is.

GF are meant to customizable depending on personal preference. Some times a diver wants to be more conservative/aggressive with his dive profile other times he might be trying to match the non-Bulhmann algorithm another one of his dive computers is using.

I think you are seeing a lot of computers running the Bulhmann with GF because the Bulhmann is considered the "standard" deco model and when you combine GF the diver can have it act like the deep stop/bubble models if they so wish.

You are parroting superficial information. If I wanted information on VPM or RBGM, I would ask

 

[rhwestfall]

rough crowd today....

 

[CptTightPants21]

Sorry, get some more dives, experience, and knowledge

---------- Post added September 29th, 2015 at 11:27 AM ----------



You are parroting superficial information. If I wanted information on VPM or RBGM, I would ask

Why don't you learn how to speak English and clarify what you need help with.

I don't expect I will have the knowledge to go into the level of scentific detail you are looking for, but with your attitude I wouldn't even if I could.

 

[tursiops]

 

[PfcAJ]

Not if you ask 10 people who know what they're talking about.

Then you'll get at least 15.

 

[uncfnp]

Can someone direct me to where Shearwater says what its recreational GFs are?

 

[wedivebc]

Are you 1 of the 10, give me some useful information

Unfortunately since I am not familiar with any of the above mentioned iterations of GFs I can't be much help. I can say that I am pretty sure Buhlmann was not involved in any GF versions of his model so it is unlikely he intended his fomulae to be used with any specific GF setting as you had stated above.
Resolving NDL into a computer algorithm that is intended to work under the assumption there is no such thing as a no deco dive is apparently quite difficult. One dive computer programmer once told me a lot of tweeking goes into making a computer transition from NDL to an assigned ceiling. With that in mind PfcAJ's statement above is probably correct.

 

[DiveNav]

.... Can someone help shed light on this topic?

The original Buhlmann ZH-L16C algorithm does not have gradient factors. Those have been added later on by third parties to make the original algorithm a bit more conservative.

It is very difficult to say how various manufacturers have "optimized" their implementation of the XH-L16C algorithm. They could have added some gradient factor. They could have modified the half times. They could have modified the over-pressure gradients. Or any combination of the 3.
You can see in this post how we "optimized" our own implementation of the Buhlmann ZH-L16C algorithm.

You can use the Selective Gradient feature in divePAL Windows to design/test your own implementation of the ZH-L16C algorithm

Alberto (aka eDiver)