Petrel Settings and Display

[Michael Guerrero]

I just got a Petrel and am curious what others select for their GFs and middle row display options. The 30/70 default seems somewhat conservative on the GF Hi. Also, do you set the salinity or just leave it on the Euro standard default? Anyone actually use it's dive planner for square profile cut sheets?

This is for OC only.

Thanks.

Mike

 

[Dsix36]

I will not say what GF I run simply because I think that you should leave it set at the default unless you have enough knowledge of it to make a safe and informed decision. Just setting it to what others use is not a very good way to do it. I am not trying to be a d**k, but rather trying to get you to study the GF algorythm setting and learn it properly rather than going by blind faith of others. too many variables to make a blanket statement on settings.

 

[Michael Guerrero]

OK...how about any of the other questions I asked?

And for what it's worth, I really am just curious. I wouldn't change something just because someone else does it . I think the GUE guys teach 30/85 for air, which doesn't seem too aggressively close to the M-values. Anyway...thought I would just clarify.

 

[DevonDiver]

Kinda what Dsix36 said, in regards to GF: it's a personal decision that should reflect (1) an understanding of GFs and (2) your own personal physiology and the diving you do.

Unless there is cause to expect a drastic variation in salinity (some places have), then default.

I suspect the square profile is used for dive planning by many - plan your dive, dive your plan. I wouldn't hit the water without knowing the outline of my depth, time, deco obligation and gas. Whether you use to computer to flexibly reduce from that in real time, or whether you stick to a static run-time is probably going to be determined by your dive team (i.e. all team members using same approach, same algorithm, same settings or not)

 

[Dr. Lecter]

Center row for me is Max, GasPO2 and GF99.

I use the planner if V-Planner is not available for some reason.

What I run the algorithm at depends on the dive. Deep on air with a lot of exercise (awkwardly reboarding small boat) right after deco? Maybe 20/70 or VPM +3/70. Recreational depths for the same time period the AL80 divers are in the water? Maybe the old original setting of 30/85 or VPM 0 or +1. As Dsix already pointed out, mucking about with these settings requires either an understanding of what they do, or, a desire to take a chamber ride.

 

[Superlyte27]

OK...how about any of the other questions I asked?

And for what it's worth, I really am just curious. I wouldn't change something just because someone else does it . I think the GUE guys teach 30/85 for air, which doesn't seem too aggressively close to the M-values. Anyway...thought I would just clarify.

HUH? GUE is teaching a 30/85 gradient factor?

 

[Michael Guerrero]

Thanks DD, and of course your right about individual physiology and profile. As for the planning, was more getting at the Petrel vs. V-Planner or DecoPlanner, etc. Appreciate the viewpoint. It's certainly nice not having to haul a laptop around, though I suppose I could get a smart phone one of these days.

Thanks also Doc. I'm debating about having CNS % in there. And agree 100% that there are appropriate times for more conservatism and times for less.

 

[electric_diver]

IIRC 30/85 was the default setting on the Predator.

I found the 30/70 petrel default setting was too conservative and gave deep stops that were too long and too deep. I've been experimenting with the settings to see what works best for me. I also read Eric Baker's paper on understanding M values.

I used the dive planner to test the effects of varying the GFs one morning while my buddy drove the car to the dive. Other than that I haven't used the dive planning feature.

I think I left the salinity alone.

 

[Michael Guerrero]

So, semi resurrecting this thread, I'm interested to know what options people choose for their middle row in OC.

No need for further discussion about GFs . Pretty sure I could teach a class on it at this point.

 

[Mr. Black]

My middle row on OC:

GF99 ppO2 @+5

This will put @+5 value right above TTS value allowing rapid comparison with minimal risk of confusion. GF99.... I hope I will never need it but I choose to have it a permanent fixture on the main screen so I can always see it without button presses if I need to.

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