OP
I have learned a little bit more about the G2 Tek algorithm. I am sure it changes no opinions on who will or will not use it, but I do like to understand how the computer algorithm works and share that information.
Deco schedule does not match Shearwater or Scubapro HUD
While the G2 Tek is more conservative than the Shearwater, it is not because they have implemented an incorrect or wrong ZH-L16C + GF algorithm. It is the inputs they chose to use for the algorithm that cause the differences.
I know this is not a great analogy, but the Pythagorean theorem is a2 + b2 = c2. If I use a = 1.1 and b = 2 while another person uses a=1 and b=2, it is not that the equation is wrong, it is that the inputs to the equation were different. I believe this is what is happening with the ZH-L16 algorithm used by Scubapro. Scubapro does document this in the user manual. It is in the Altimeter section of the user manual. I have copied the text from the section below, and made the important text bold.
"Barometric pressure is variable, changing with weather and atmospheric pressure at any particular elevation. Dive algorithms use altitude classes which are directly derived from barometric pressure. Displayed altitude is determined based on the current barometric pressure and is therefore a relative value. "
Scubapro uses altitude classes as the input into the decompression algorithm. They use the top end of the altitude class. So if the Altimeter is measuring pressure at Sea Level, you are in altitude class C0 and the input into the algorithm is 1,000 meters. Playing around in Multideco and changing the Dive Elevation depth between 0 and 1,000 meters does seem to give run times with a difference similar to what I saw when I performed an actual test dive with the Shearwater and G2 Tek.
Dive Planner shows shorter NDL times.
There is a double hit here. The dive planner is using the current altitude class (1,000 meters at sea level) and the G2 Tek dive planner assumes the dive starts at the depth indicated. The G2 Tek dive planner does not calculate a descent rate like the Shearwater and Garmin computers do.
Scubapro HUD is different than the G2 Tek
This has been confirmed. Scubapro HUD does not use altitude classed and uses the measured barometric pressure.
An interesting note...
For anybody that liked the SEABEAR computers (Scubapro bought the company in 2015), the founder, Dr. Arne Sieber stayed with Scubapro as the R&D Manager for Scubapro Dive Computers until 2017. Dr. Sieber founded Oxygen Scientific, which has solid state O2 sensors and dive computers with wireless PO2 and Air integration. Halcyon will sell them in their Symbios CCR ecosystem.
Deco schedule does not match Shearwater or Scubapro HUD
While the G2 Tek is more conservative than the Shearwater, it is not because they have implemented an incorrect or wrong ZH-L16C + GF algorithm. It is the inputs they chose to use for the algorithm that cause the differences.
I know this is not a great analogy, but the Pythagorean theorem is a2 + b2 = c2. If I use a = 1.1 and b = 2 while another person uses a=1 and b=2, it is not that the equation is wrong, it is that the inputs to the equation were different. I believe this is what is happening with the ZH-L16 algorithm used by Scubapro. Scubapro does document this in the user manual. It is in the Altimeter section of the user manual. I have copied the text from the section below, and made the important text bold.
"Barometric pressure is variable, changing with weather and atmospheric pressure at any particular elevation. Dive algorithms use altitude classes which are directly derived from barometric pressure. Displayed altitude is determined based on the current barometric pressure and is therefore a relative value. "
Scubapro uses altitude classes as the input into the decompression algorithm. They use the top end of the altitude class. So if the Altimeter is measuring pressure at Sea Level, you are in altitude class C0 and the input into the algorithm is 1,000 meters. Playing around in Multideco and changing the Dive Elevation depth between 0 and 1,000 meters does seem to give run times with a difference similar to what I saw when I performed an actual test dive with the Shearwater and G2 Tek.
Dive Planner shows shorter NDL times.
There is a double hit here. The dive planner is using the current altitude class (1,000 meters at sea level) and the G2 Tek dive planner assumes the dive starts at the depth indicated. The G2 Tek dive planner does not calculate a descent rate like the Shearwater and Garmin computers do.
Scubapro HUD is different than the G2 Tek
This has been confirmed. Scubapro HUD does not use altitude classed and uses the measured barometric pressure.
An interesting note...
For anybody that liked the SEABEAR computers (Scubapro bought the company in 2015), the founder, Dr. Arne Sieber stayed with Scubapro as the R&D Manager for Scubapro Dive Computers until 2017. Dr. Sieber founded Oxygen Scientific, which has solid state O2 sensors and dive computers with wireless PO2 and Air integration. Halcyon will sell them in their Symbios CCR ecosystem.
