When is ZH-L16C GF not ZH-L16C GF? When it is a G2 Tek computer

[coconutdiver976]

Obviously, we adapt. The question is, which computer decides HOW to adapt? The one on your wrist, or the one between your ears?



I'm not sure I follow how a computer that will lock out and an instructor that only allows Shearwater are "not much different".

What I will say from an instructor's point of view are the following:

- I'm not able to be fully proficient and knowledgeable about every computer on the market. Not even every tech-capable computer. And I kinda feel like it would be unreasonable for a student to expect that.

- I need for my students' computer to behave in a way that is predictable and that I expect. Giving a really long deco stop when nobody else on the dive had a deco stop at all was - from my perspective - not something I could predict or would have expected. As such, I choose not to accept future students that use that computer. I.e. based on both the manual (as reported by Sevenrider860) and my personal experience, I find that computer unacceptable for use in tech diving.

- In the future, I may be asked to teach someone with some other non-Shearwater computer that is purported to be tech-capable. Say, for for example, a Ratio or HW OSTC computer. As I don't KNOW those computers, accepting that would run the risk of finding out that, like the G2Tek, that other computer behaves in some unpredictable and unexpected way that makes it unacceptable for tech diving. Maybe not. But, as I am not fully proficient and knowledgeable on those other computers, I would not want to run the risk. I would accept other computers, as long as the student has at least one Shearwater. I might even rent or loan a Shearwater to a student that doesn't have one. But, I don't think I would take on another student that did not have a Shearwater and wouldn't use one that I provided. They can do whatever they want after (if) they finish their certificaiton. I am not the Scuba Police. But, it disrupts the class and impedes progress when you have to deal with a computer that does not work as expected.

hello

I'm just a French diver who joined this excellent forum this morning. I have a tec background; I'm a hypoxic trimix diver (TDI). Even when I dive with air, deep, with or without nitrox or oxygen deco, I apply the same safety requirements that I was taught a long time ago. As for deco, I've had OSTCs since 2007-2008; I've logged just under 2,000 dives with them. I dive with 2 computers, with the same decompression settings. A few years ago, I had a Perdix AI, since replaced by the Perdix 2; so I dive with an OSTC (I have either the 2 or the +) and a Perdix 2. In terms of deco, with GF85-85, I rarely have more than a minute's difference between the two. I've noticed this for about 500 dives (with both). The perdix takes me out hardly any earlier. I live overseas and will be returning to France within the next three months, resuming my dry suit and square dives on wrecks. For the text, you'll have to excuse me: I'm using an online translator... Thanks for reading.

 

[Sevenrider860]

Hi Divers,

We have conducted testing that might interest you and may answer some of your questions. More details are available here: Info - Deeply Safe Labs: A website for dive computer testing

On the subject, we have not tested either the G2 Tek nor the G3. However, we have tested the Luna 2.0, which we can confirm computes higher decompression times than theoretical unmodified ZH-L16 C. You can find the test results here: Deeply Safe Labs

@Sevenrider860 I have gone over the manual you quoted, but couldn't find any mention that altitude classes use the upper bound for calculations. This would be in contradiction with previous Uwatec and Scubapro computers, up since the first Aladin, in 1987. Could you please indicate where you found that information? Thanks in advance.

Best regards,
Eric Frasquet,
Deeply Safe Labs.

The statement that the decompression algorithm takes the measured barometric pressure and then assigns an altitude class is in the manual. The information that the upper end of that altitude class is used was made during a call with Brad Lally, Senior Director of Quality and Compliance where we discussed why the ZH-L16C was not matching with Garmin, Shearwater, or even the Scubapro HUD.

 

[scubadada]

Scubapro is running a significant sale on their dive computers, perhaps to make up for low sales. I wouldn't imagine that most know that their computers, aside from the HUD, do not really run Buhlmann ZH-L16C with GF. I still think that this is pretty outrageous.

 

[lexvil]

Scubapro is running a significant sale on their dive computers, perhaps to make up for low sales. I wouldn't imagine that most know that their computers, aside from the HUD, do not really run Buhlmann ZH-L16C with GF. I still think that this is pretty outrageous.

Still considering a g3 to see how it matches or can be set to match the HUD.

 

[scubadada]

Still considering a g3 to see how it matches or can be set to match the HUD.

Would love to see your results

 

[lexvil]

Would love to see your results

It’s been in my cart at a few places since yesterday but haven’t pulled the trigger yet, I very tempted, maybe need to put my G2 up for sale to put me over the edge…

 

[BoltSnap]

Scubapro is running a significant sale on their dive computers, perhaps to make up for low sales. I wouldn't imagine that most know that their computers, aside from the HUD, do not really run Buhlmann ZH-L16C with GF. I still think that this is pretty outrageous.

Was this announced on their official website or just offerings by their dealers in US?

 

[Sevenrider860]

Still considering a g3 to see how it matches or can be set to match the HUD.

G3 with GF should be just like G2 Tek. If you switch to ZH-L16 ADT MB PMG the HUD has MB Level 0 to 5 and the G3 has MB Level 0 to 9 so hard to make a match there. Maybe a GF High 5 more than the HUD will get you close.

The big difference is that the HUD does not use Altitude Classes. So at sea level the G3 will be a bit more conservative than the HUD at equivalent settings.

 

[BoltSnap]

G3 with GF should be just like G2 Tek. If you switch to ZH-L16 ADT MB PMG the HUD has MB Level 0 to 5 and the G3 has MB Level 0 to 9 so hard to make a match there. Maybe a GF High 5 more than the HUD will get you close.

The big difference is that the HUD does not use Altitude Classes. So at sea level the G3 will be a bit more conservative than the HUD at equivalent settings.


View attachment 836201

I don't see a huge difference in this chart. Does it get worse somewhere else?

 

[Sevenrider860]

I don't see a huge difference in this chart. Does it get worse somewhere else?

This is a clip of a chart previously posted that only shows the difference between the HUD and G2 Tek NDLs using the identical GF algorithm settings. The original chart showed the G2 with MB and included Shearwater and Garmin using the same GF settings as the Scubapro.

You say "not a huge difference". I say why is the identical algorithm giving different results? Of course we now understand why....the algorithms are not identical. If I wear a Petrel and a Nerd...the algorithms are identical. One cannot be blamed for expecting the same algorithms on a Scubapro wrist computer and Scubapro HUD to give identical results.

Things do get worse when you get beyond the NDLs. I think this thread started by identifying the extra decompression time that the G2 Tek accumulated compared to Garmin and Shearwater.,