What's your Low Gradient Factor Selection

[zirk]

I ran a 200 foot dive 30 mins, with a 40/80 gF. The stops ended at 42feet if I was reading it right.

 

[nobody]

I ran a 200 foot dive 30 mins, with a 40/80 gF. The stops ended at 42feet if I was reading it right.

Oh, i'm from the uk so the depth is metres, not feet

 

[zirk]

ahhh ok i'll go back and try it again

 

[zirk]

There we go... working now. Thanks again for putting this out there

 

[nobody]

Surely if you remove deep stops from an active calculation the algorithm automatically creates longer shallow stops? You'd need to be pretty dumb to cut deep stops tables then ignore some of them :dunce:

To some extent. Take an example dive to 80m for 20 minutes with a setpoint of 1.4 and 10/50 as dil

If we take 20/80 as a deep profile you can see that by switching to 50/70 you spend a similar amount of time in the water but with a lower exposure to supersaturation. If you go to 70/80 you're out of the water quicker but with a high exposure. Obviously this assumes that a) i've got my maths right b) it's total exposure across all compartments that matter c) the algorithm is correct (and we know that isnt true) and d) the differences in numbers are clinically significant

If you look at the table for 50/70 for that dive you can see you have ongassing up until the 12 meter stop so that confuses things

Like i said i could have got this all horribly wrong but it seems to make sense to me.

EDIT: full disclosure i don't do any technical diving (yet) i'm just very interested in the therory around it and rebreathers

 

[Fldvr]

I started tweaking my Gf a while back also and have ended up at 80/90. Others that I know have found a point where they start noticing some niggles and have backed off slightly from there.
That being said on deco I clear "way" before they do but I choose to stay....knowing that I can ascend safely at any point.
FWI. I dive frequently and made small changes over a period of time.
Henry

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[zirk]

What is/are "Dens"?

 

[nobody]

What is/are "Dens"?

Gas density.

 

[Captain Starfish]

After reading all the stuff, I went from my usual 25/85 which has good days and bad (for me) to 40/75 for a dive. Indicator niggle afterwards. So the next few dives were 30/80 and no dramas there.

 

[L'eauB'low]

I set 85/85 in my computer(s) but probably dive closer to something like 40/75.

Although I try to pay attention to my GF when I reach my first stop and when surfacing, it would be nice to be able to see what GFs I actually dove after downloading to the desktop.

 

[Mark Chase]

Surely if you remove deep stops from an active calculation the algorithm automatically creates longer shallow stops? You'd need to be pretty dumb to cut deep stops tables then ignore some of them :dunce:

Actualy it doesnt because all the deep stops are doing is increasing some tissue loading so adding shalow deco time

The best example of this was the old VR3 which would rack up a lot of extra shalow time if you didnt ascend quickly enough or added stops along the way. That said I notice when running higher GF lows if i have to stop and wait for a buddy whos still insistant on deep stops my shalow stop time increases.


So by cutting out the deep stps you also reduce the shalow stops. By cutting out the deep stops and increasing the shalow stops your just softening the overall deco.


As a quick guide:

Dive to 70m for 45mins on 15/50


10/80 GF Deco is 224mins deco with 85mins @ 6m total 108mins from 10m & up

50/80 GF Deco is 201mins deco with 78mins @ 6 toal 100mins from 10m and up


SO not much in it on the shalow stops but the 10GF dive is 23mins longer


To get that extra 23mins I need to run 50/65 deco with 118 mins above 10m and 94mins @ 6


ATB

Mark

 

[jturner]

I've been running 30/80 for a while and am currently on 40/75. Rationale is embarrassingly unscientific! :

 

[tripntx]

Took P2 CCR Diver course from Peter at Add Helium, which is where I first listened to GF explanation. Been reading online about GF. I'm not able to debate the subject, and can only say what I chose and why. My GF is currently set at 80/85, and I chose this setting because I prefer to go shallow to off gas instead of remaining on deep stops while continuing to on gas. These setting work for me, and I feel safe diving them. Taking Normoxic CCR from Add Helium in June, and I hope to discuss my GF settings with Peter.

 

[Ben Field]

Actualy it doesnt because all the deep stops are doing is increasing some tissue loading so adding shalow deco time

Sorry, my bad for making a frivolous comment, I meant if you cut deco somewhere you still serve it somewhere else- as such avoiding "deep" stops does means you serve the debt shallower. I was replying to the poster who questioned my post about using deep stop tables but knowing you can blow off the deep parts, my point was if you cut tables with deep stops then don't do them the shallow stops generated under the deep stop protocol aren't necessarily the right stops, you need to recalculate from scratch.
But anyway- its moot now people are lifting their GF Lo.

 

[garethingham]

Are people adding any Pyle type pauses on the more aggressive 50+ low GF deco or going straight to the 1st stop as called by the schedule?


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[Fldvr]

After reading all the stuff, I went from my usual 25/85 which has good days and bad (for me) to 40/75 for a dive. Indicator niggle afterwards. So the next few dives were 30/80 and no dramas there.

When one comes to the realization that most of the posts here with fancy charts and intellectual conversations are
in fact just attempts to justify one line of thought, they do nothing to further the exploration of proper deco procedures.

So yes what you have done here is...Armed with knowledge provided by the industries leading experts.. come the conclusion with
some conservative experimenting arrived at the same conclusion which they all acknowledge regarding the application of "Modern Deco Theory".

If we all took this approach and quantified the results as a whole then we would have some factual basis as to why and when we are using the deco procedures we are using.

Until then we are just filling up internet space with Half truths and pseudo science, just look at the outcome of some of those discussions on the forums
if you need further evidence

Henry

 

[diverklondike]

Well stated!

When one comes to the realization that most of the posts here with fancy charts and intellectual conversations are
in fact just attempts to justify one line of thought, they do nothing to further the exploration of proper deco procedures.

So yes what you have done here is...Armed with knowledge provided by the industries leading experts.. come the conclusion with
some conservative experimenting arrived at the same conclusion which they all acknowledge regarding the application of "Modern Deco Theory".

If we all took this approach and quantified the results as a whole then we would have some factual basis as to why and when we are using the deco procedures we are using.

Until then we are just filling up internet space with Half truths and pseudo science, just look at the outcome of some of those discussions on the forums
if you need further evidence

Henry

 

[Baron015]

Henry, too much mystery for me to get it, what are the outcomes you were referring to ?

Would it be better to suppress these discussions which are really just asking what other people are doing and how they are getting on ?

I find this thread quite interesting. There is already a much wider discrepancy between what people are using than I thought there would be.

 

[Fldvr]

Henry, too much mystery for me to get it, what are the outcomes you were referring to ?

Would it be better to suppress these discussions which are really just asking what other people are doing and how they are getting on ?

I find this thread quite interesting. There is already a much wider discrepancy between what people are using than I thought there would be.

Whoops, sorry if I came across as critical of a question being asked! I hope you remain interested as there is a lot to be gained information wise occurring in this
thread!!
I for one am happy to see people actively thinking about what is supposedly the safest profiles to use.

Henry

 

[Captain Starfish]

Regardless of the best model with the best statistical results, we all sit on different points on that curve and will move around it day to day. I know guys that will rock a 110/110 profile and no dramas at all, guys that have never toxed on a ppO2 of 2.0 or higher, etc, etc, etc. For me, personally, I know I've had a minor bend on 100/100 (old Uwatec computer) and so I get the feeling I can't be too aggressive - for me. That 40/75 dive I felt the niggle come on during the 6m stop and wrote it off at the time as a shoulder strain from hanging onto the shot or something. But the fact that it came on during the stop suggested to me that I might have been better off staying a little lower down a little longer - easy tweak, just drop the first number a bit and see how that goes. In a year or so I may well try popping it up 5% and seeing how that goes.

Point? It's different for all of us and we each of us needs to work out for ourselves where that sweet point is on the compromise between spending two days ascending vs feeling good at the end of the dive. Models are great for a starting point, but they need tuning.