forum.heinrichsweikamp.com

Hi OSTC Team,

Is there a plan to inplement GF99 und SurfGF into an Software Update? Could be benificial.

cheers

chrischd

Hi Chris,

Could you explain what you mean ?

Regards.

Hi Didier A. Defay,

GF99 is the current real-time relashionship between the pressure of nitrogen dissolved within a tissue and the ambient pressure surrounding you.

SurfGF is the pressure difference if you would be surfacing immediately.

You can use it for example to decide you optiomal length of your safety stop.

br
Chrischd

In one of the custom views, there is 'Saturation', this is the current overpressure of the leading compartment (N2 + He combined). In the same custom view there is 'Ceiling', this is the depth at which the leading compartment will hit the GF high. If you prepare alternative GFs with GF high set to 100% and switch to these GFs, it will show you the minimum depth you can go to just stay inside the model. So it is not directly your 'SurfGF' but something similar, or even more informative, as supersaturations above 100% are strictly speaking outside of the model and can mean anything & nothing depedning on the diver's body 'performance' on handling supersaturations.

Hi Ralph,

Thanks for your Answer.
I know these views.

Saturation is not Equal the information you get from GF99 (Shearwater). To make an example:

Saturation is the load of the leading tissue in %. 100% would mean fully saturated.

Comparison with GF99:

Saturation 100% leading tissue (Saturation is an absolute figure), would mean in terms of GF99 0% Tissue pressure equal ambient pressure (is a relationship between 2 figure).

GF99 "on GAS" would mean ongasing and any % value of the GF99 would indicate the presure difference between ambient pressure and tissue pressure (Supersaturation).
Hence GF99 value 30% would indicate offgasing 30% away from the M-value. Hence you can monitor in real time your decompression and the rate of your Dekompression stress.
Quite handy, even for non Deco Dives.

And additionaly to the GF99 the SurfGF would show you the Pressure difference in real time if you are surfaceing.

Hence with GF99 you monitor the On and Offgasing and with the SurfGF you can monitor, what GF% you would have if you surface. Hence I can decide in realtime, wheter i want to surface with a GF of 80% or prolong my offgasing to a SurfGF of 70% to add more conservatism.
(For sure above 100% M values are not within the Model and don´t make sence)

cheers
Chris

Thanks Chris for the extended explanation!

One remark: for historical reason, the OSTC value 'saturation' indeed is the supersaturation value, so 100% means that the leading compartment is at the M-value. Regarding the GF99 values, that will be a strategic decision to be taken by Matthias.

BR
Ralph

Ah thanks for the Info then is Saturation Equal GF99?

I don't get why they call it GF99. Isn't GF100 what you need? The Saturation value in the OSTC is the current over saturation of the leading tissue. GF Surface would be this value projected into an instant (?) ascent to the surface.

Regards,
Matthias

Hi Matthias,

Yes The Name GF99 isn´t quite good one, I don´t know why they call it like this. Supersaturation would be a better name.
Hence I will play around with both Computers It might, that OSTC Saturation is Equal to GF99 Shearwater. I will try.

And Yes Surf GF would be the projection to a direct asscent. Hence if you can see in the SurfGF 90% and you want to be a little more conservative, you could look to a Depth where Supersaturation is arround 35% and wait a little bit more, untill SurfGF drops to like 70%
Quite Handy.

br
Chrischd