Teric and Nitrox diving - Rec divers take care re method of changing gas (affects MOD).

[KenGordon]

Huh? This is a fairly incoherent post....

Evolving Thought on Deep Decompression Stops

Fraedrich Study (2018)(9)
A study published in December 2018 Diving and Hyperbaric Medicineexamined whether computers using four algorithms (Suunto RGBM, VPM-B, EMC-20H, and Bühlmann ZHL-16C) conformed with what the US Navy had determined were the limits of safe ascent protocols in experimental dives with known decompression outcomes determined in the 2008 NEDU study. For the purposes of this study, the no stop time, first stop depth and total decompression time were examined and compared. According to the report, none of the computer algorithms passed all the test requirements with factory-default conservatism, but the Bühlmann ZHL-16C and Suunto RGB could with user-defined settings. Here are the relevant findings:

• Fraedrich D. Validation of algorithms used in commercial off-the-shelf dive computers. Diving and Hyperbaric Medicine. 2018 December 24;48(4):252–258. doi: 10.28920/dhm48.4.252-258. PMID: 30517958.)

If it had been an old Zoop without deep-stops it would have met his target.

I think his target was a bit bogus though.

 

[tursiops]

Evolving Thought on Deep Decompression Stops

Fraedrich Study (2018)(9)
A study published in December 2018 Diving and Hyperbaric Medicineexamined whether computers using four algorithms (Suunto RGBM, VPM-B, EMC-20H, and Bühlmann ZHL-16C) conformed with what the US Navy had determined were the limits of safe ascent protocols in experimental dives with known decompression outcomes determined in the 2008 NEDU study. For the purposes of this study, the no stop time, first stop depth and total decompression time were examined and compared. According to the report, none of the computer algorithms passed all the test requirements with factory-default conservatism, but the Bühlmann ZHL-16C and Suunto RGB could with user-defined settings. Here are the relevant findings:

• Fraedrich D. Validation of algorithms used in commercial off-the-shelf dive computers. Diving and Hyperbaric Medicine. 2018 December 24;48(4):252–258. doi: 10.28920/dhm48.4.252-258. PMID: 30517958.)

If it had been an old Zoop without deep-stops it would have met his target.

I think his target was a bit bogus though.

Yes, I read John's article, and look forward to reading the source material from Fraedrich when it becomes available. have you seen it? Are you just speculating on the ZOOP, or is your comment based on something else?

By the way, it was the other part of your post that was incoherent.

 

[Jay]

Sure. All in OC Rec. Dive Mode

Display MOD on the Home screen.
Have two gases listed 21% and 32%.
Ensure your MOD PPO2 and Deco PPO2 are different.
Via Setttings/edit gas. Make 32% the Active gas by turning off 21%
Note the MOD (first MOD reading)

Go to Select Gas. Change the gas to 21 then back via this way to 32.
Note the MOD 2nd reading)

The two MODS should be different.

 

[KenGordon]

By the way, it was the other part of your post that was incoherent.

Stuart asserts it is ok not to be able to have no gases selected in a menu because you can go up and down. I comment that since the gas list has three entries cycling is only slightly worse, compared to Tech mode with even longer tedious cycling. However, you have to discover that you cannot deselect the last gas by trying and then mess about selecting a second gas and then deselecting the first.

 

[KenGordon]

have you seen it?

Yes, I have paid my money. I was disappointed. I’d have to double check but I came away with the impression that a pass constituted falling between the two plans used in the NEDU deep stops paper. However there are plenty of interesting articles, it is very cheap to join and supports a worthy cause.

 

[stuartv]

Stuart asserts it is ok not to be able to have no gases selected in a menu because you can go up and down.

No, I did not. I simply made the observation that your description of the tedium involved is correct for a Perdix, but it is not correct for a Teric.

 

[stuartv]

Sure. All in OC Rec. Dive Mode

Display MOD on the Home screen.
Have two gases listed 21% and 32%.
Ensure your MOD PPO2 and Deco PPO2 are different.
Via Setttings/edit gas. Make 32% the Active gas by turning off 21%
Note the MOD (first MOD reading)

Go to Select Gas. Change the gas to 21 then back via this way to 32.
Note the MOD 2nd reading)

The two MODS should be different.

Okay.

Teric1:
MOD1 = 112. MOD2 (air) = 188. MOD3 = 112.
F/W version = 11
OC MOD 1.40
OC Deco 1.61

Teric2:
MOD1 = 112. MOD2 (air) = 188. MOD3 = 112.
F/W version = 11
OC MOD 1.40
OC Deco 1.61

 

[Jay]

Thanks Stuart.

Looks like it's an unintended effect of changing the way MODs are applied in FW16.

 

[stuartv]

Thanks Stuart.

Looks like it's an unintended effect of changing the way MODs are applied in FW16.

If I'm understanding the situation, it sounds like FW16 works the way it should. If I'm breathing air and I do a gas switch to EAN32, I would be doing that because I'm using EAN32 as a deco gas. In which case, it should apply the Deco MOD.

The way it works on my Terics is really not the way I think it should work.

 

[Joneill]

Okay.

Teric1:
MOD1 = 112. MOD2 (air) = 188. MOD3 = 112.
F/W version = 11
OC MOD 1.40
OC Deco 1.61

Teric2:
MOD1 = 112. MOD2 (air) = 188. MOD3 = 112.
F/W version = 11
OC MOD 1.40
OC Deco 1.61

F/W version 11? Shame on you!