Are there any "standard" tech dive profiles to compare computers/algorithms?

[DuboisP]

why not doing as V-Planner, MV-Plan or even Suunto Dive Planner ?


choose the mixes, choose the Gradient Factors (MVPlan), choose Conservative (V-Planner) or not, choose Deep Stops, choose Bulhmann coefficient for saturation/desaturation.
choose set of mixes, size of bottles

in some words : COPY what's invented elsewhere
i don't think there is a lot of things to invent (again).

but i'm working a lot with US people, and they often have the "not invented here syndrome"

did in USA ? perfect !
did elsewhere ? bad !

when digging a little, not so perfect....

 

[rossh]

Hi,
as per subject .... Are there any "standard" tech dive profiles to compare computers/algorithms?

One more question: Tech divers "play" with GF factors and/or conservative settings to adjust algorithms to their needs. Would you be interested in being able to "play" (as in change) with the core parameters of the algorithms themselves (M-value, slope, half-time ....). Or is this a big NO-NO?

Alberto (aka eDiver)

Hi, There has not been any standard profile or depth / time set to use as a base line. The settings of any comparison charts in the past, have been up to the author.

Replacing GF does have some merit. The current GF Hi/Lo system will apply it modifiers quite late in the ascent calculation, and gives us something of a "tail wagging the dog" situation. This gives the awkward problem in planning: the need to fiddle the GF to get the results you anticipated.

A better version of ZHL might be to manipulate the base coefficient values, and then allow the algo to complete, without the GF fudging. But it would still just be a time based averaging algo.

Regards rossH

 

[briaeros007]

Currently, I didn't found any papers which explains how to apply GF.
The only papers I've found about GF is how to calculate GF on buhlmann style M-Value.

So if anyone have such papers , It would be gladly appreciate.


You can try to use GF to ponderate super saturation pressure :
For example, in a personnal tool (work in progress) I juste ponderate GF if the SuperSaturation pressure begin to be a little to high in my opinion.

unit are in bar , comments are "//" (java code)
sum is the actual pressure inside a compartiment
ascentCeiling : the minimum pressure the body could support (so the minimum depth)
SaturationSafe and RiskySaturation : two arbitrary values of supersaturation

//First We get the ascent ceiling without GF
ascentCeiling = (sum - A) * B;

double SaturationSafe=1.2;//one we agree to have GF=GFmax
double RiskySaturation=2.4;//one we agree to have GF=GFmin
double diff = (sum - ascentCeiling);

//linear extrapolation : if risky : GFmin, if ok : GFmax
double GF=(GFmax * RiskySaturation - GFmin * SaturationSafe + diff * GFmin - diff * GFmax)/(RiskySaturation-SaturationSafe);

if (GF>GFmax) GF=GFmax;//Saturation safe is a little too optimistic ?
if (GF<GFmin) GF=GFmin;//Saturation risky is a little too pessimisitic ?

ascentCeiling = (sum - GF * A) / (GF / B - GF + 1);

If someone want to play with buhlmann coefficient and other, it's not so difficult if you know any programming language.
But It requires plenty of times.

 

[Kevrumbo]

Been using the following profile range & gases for the past week in Chuuk Lagoon;
20/20 trimix with Eanx50 and Oxygen for deco;
Sidemount 11L tanks with 4.2L deco bottles.

The deep wrecks of the Fourth Fleet Anchorage (San Francisco Maru; Aikoku Maru; Nagano Maru; Shotan Maru; Nippo Maru; Hoki Maru etc), all fall in the depth/BT ranges below. I just pick the average depth and the corresponding time on pre-dive planning (& on-the-fly as needed):

Depth: BT:
45m 35min
48m 30min
51m 25min
54m 20min
57m 15min

. . . And then the following same deco profile for any depth/BT combination above:

42-39m short deep stops 5 to 10sec
36m 30sec
33m 1min
30m 1min
27m 2min
24m 3min
21m 4min Eanx50 switch
18m 3min
15m 3min
12m 3min
9m 2:2min Eanx50:backgas break
6m 10min Oxygen switch
-->ascend 1m/min for 6min time to surface on O2

(based on Buhlmann GF 35/80, and Ratio Deco 1:1)
SCR: 10 to 12L/min; Water temp 29deg C.

 

[DiveNav]

I finally got from my team the internal alpha version of divePAL Tech that - among other things - allows to plan dives using "an infinite number of gasses" (those engineers .... :blinking

So I wanted to test the "very standard GUE Tech 1 dive" ..... and I have now few more questions ...

1) What descent rate does GUE typically use?
2) What ascent rate does GUE typically use?
3) Is the 30 minutes bottom time of Tech 1 including the descent?
4) What PPO2s does GUE use for the bottom portion of the dive?
5) What PPO2s does GUE use for the deco portion of the dive?

This is the dive profile that divePAL is spitting out using 10m/min for both descent and ascent, 1.4ATA for both segments and ZH-L16C.

​

Alberto (aka eDiver)