Gradient Factors - What is Everyone Using?

[boulderjohn]

That's all it takes? Cool, I'm going to go change all my GFhi to 99 right now!

I guess I should have qualified my response to the precise circumstances.

 

[CWK]

For deco diving, usually 60/75, which is in the ballpark of my friends. If they want something a little different, I do whatever we agree on. For NDL dives, I will kick the GFhi up to 85, which is essentially what I did before. The difference is that I now pay attention to the surfGF readout, and I don't surface until the number is way lower. I keep the GF higher during the bottom part of the dive so that people don't freak out about my going into deco during the dive, and then I wait for the surfGF to get lower during the safety stop.

A couple years ago I mentioned in a thread that on NDL dives I don't bother changing the GFs from my tech settings, so I go into deco by a couple of minutes on NDL dives, knowing that if I took a minute to raise the GFs I would still be within NDL. An imbecile who had dedicated his life to making my ScubaBoard existence miserable went nuts on that, starting an entire thread about how I was irresponsibly advocating going into deco on NDL dives and should be banned from ScubaBoard. By raising my GFhi, I avoid dealing with such imbeciles.

I totally get where you are coming from re recreational no deco dives.

I run Rec mode 99/99 on my Teric and surface when surface gf drops to 75 or less primarily to show DMs that I have not gone into deco cos they cannot understand how I get so much bottom time and do longer safety stops. Otherwise I would set it up in Tec mode 75/75 and stay below surface gf of 100 as this would give me safety stop info which unfortunately would show as deco and may require an explanation that may not be understood.

 

[rjack321]

For deco diving, usually 60/75, which is in the ballpark of my friends. If they want something a little different, I do whatever we agree on. For NDL dives, I will kick the GFhi up to 85, which is essentially what I did before. The difference is that I now pay attention to the surfGF readout, and I don't surface until the number is way lower. I keep the GF higher during the bottom part of the dive so that people don't freak out about my going into deco during the dive, and then I wait for the surfGF to get lower during the safety stop.

A couple years ago I mentioned in a thread that on NDL dives I don't bother changing the GFs from my tech settings, so I go into deco by a couple of minutes on NDL dives, knowing that if I took a minute to raise the GFs I would still be within NDL. An imbecile who had dedicated his life to making my ScubaBoard existence miserable went nuts on that, starting an entire thread about how I was irresponsibly advocating going into deco on NDL dives and should be banned from ScubaBoard. By raising my GFhi, I avoid dealing with such imbeciles.

I use the "tech" settings in my shearwater with the same GFs as I normally use (50/75). I still don't get into deco on my OC 32% dives, mostly because I multilevel them. Anything mix is on CCR nowdays

 

[huwporter]

As an aside, I claim (slightly indirect) responsibility for the 'surface GF' feature in Shearwater computers. I emailed them in 2017 to suggest a new feature where the user could display the gradient factor that they would experience if they immediately ascended 3m/10 feet (I called it "GF@-3m"), and got an email back saying it was an interesting idea that they hadn't heard before and that they would consider adding it in a future update. Then the 'SurfGF' feature turned up in the Teric about 6 months later, and in the Perdix as a software update about 6 months after that, so yeah, you can thank me for that one.

(I'll admit 'SurfGF" is a better piece of information for rec divers than my original idea, and also for tec divers at the very end of their dive, but not so useful for tech divers in the early part of an ascent where it really isn't particularly useful to know that SurfGF is like 250% or something...)

 

[Divin'Papaw]

I'm currently doing only recreational dives. I formerly used the standard Medium GF settings (40/85) but have switched to 70/90. I've also added SurfGF to my Perdix display and have started monitoring it throughout the dive. I've only been doing that for the past few dives so I'm still in the learning mode with that new feature.

 

[kensuf]

That's all it takes? Cool, I'm going to go change all my GFhi to 99 right now!

Me too.

 

[cathal]

You hear this a lot, and to a certain extent pretty much everyone has this approach to some degree. The problem is you have no way of knowing how well it is working for you. There is a range of GFs that will work for you, and you have no way of knowing after a dive where you were on that range. You may have been near the edge of DCS on every one of those dives and didn't know it.

I have used 50/85 a whole lot in the recent past. I was using that setting the day I did two dives with very light deco (2 minutes) and doubled my deco time on each. I gave those settings a lot of thought while I was in the chamber. I still don't think they are all that bad, but....

As you know sub optimal gas dynamics during a dive have numerous other predisposing factors than just GF factors alone.

 

[macado]

You hear this a lot, and to a certain extent pretty much everyone has this approach to some degree. The problem is you have no way of knowing how well it is working for you. There is a range of GFs that will work for you, and you have no way of knowing after a dive where you were on that range. You may have been near the edge of DCS on every one of those dives and didn't know it.

I have used 50/85 a whole lot in the recent past. I was using that setting the day I did two dives with very light deco (2 minutes) and doubled my deco time on each. I gave those settings a lot of thought while I was in the chamber. I still don't think they are all that bad, but....

I generally agree. There are just too many factors and nobody really has the "right" answer unless you're getting a doppler bubble test after diving. That's why I state that with the caveat that what works for me may not work for someone else, hell..it may not even work for me at some point. I was just throwing in my data point that these settings have worked fairly well for me for past 5 years.

I try to look for warning signs like fatigue, muscle aches, minor "niggles" In general I feel pretty good after these dives. Not tired, no muscle aches or joint pain but of course it just takes one DCS hit for me to re-evaluate these settings.

I honestly don't even like telling people my GF factors because in recent years it seems to become some sort of "pissing contest" about who runs the highest or "best" GF settings.

 

[boulderjohn]

I generally agree. There are just too many factors and nobody really has the "right" answer unless you're getting a doppler bubble test after diving. That's why I state that with the caveat that what works for me may not work for someone else, hell..it may not even work for me at some point. I was just throwing in my data point that these settings have worked fairly well for me for past 5 years.

I try to look for warning signs like fatigue, muscle aches, minor "niggles" In general I feel pretty good after these dives. Not tired, not muscle aches or joint pain but of course it just takes one DCS hit for me to re-evaluate these settings.

I honestly don't even like telling people my GF factors because in recent years it seems to become some sort of "pissing contest" about who runs the highest or "best" GF settings.

As I indicated, I got bent on that setting, but I am still likely to use it on the same kind of dive.

 

[DavidFL]

70/85 on mostly rec dives; having fun monitoring SurfGF