Deco calculation with travel gas

[ido]

Hi,

Tried to do deco calculation of dive with trvael gas, though this seems impossible as gas change only occurs during ascent, so what happens is that travel gas is being used for bottom gas, ending in >250% CNS and some unrelevant deco stops.
Am I missing something or is it a missing feature?

Thanks,
Ido

[JeanDo]

This is a missing feature.

The > kludge is to forget about the travel gas, start (planning) with the bottom gas, which is coherent with an instant descent.

Regards,

[DTR.Diver66]

Hello,

is it possible to implement a travel gas in the gas list? It would be nice to have a gas list with 1 travel gas, 5 bottom gases and 3 deco gases for oc. So the bottom gas will be the first gas as it is currently Also, it would be nice to have a variable rate of ascent. for example: up to the first Deco Stop 8m/min, 3m/min in deco areas and from 6m 1m/min to surface.


Regards B)

[tiefunten]

If you have the option to use a travel gas an 3 deco gases - for which reason do you need 5 bottom gases then!? And if you calculate descent with the bottom gas instead of the travel gas, this won't have that much effect on deco calculation to be worth risking problems with complicating the code/calculations in my opinion.

[sailor]

Hi,

i also vote to leave the computer on bottom gas when using a travel gas for descent.
This reduces taskload, does not harm the deco calculation and keeps the code more simple.

Reiner

[scubatinoo]

But it would be nice to have separate gas lists for bottom and deco gas. Or at least different gas names like
B1 ... B3 for Bottom gas 1 to 3
G1 ... G5 for Deco gas 1 to 5

During descend the gases G1 ... G5 are ignored and only recommended during ascend as better gas...

[Bardass]

don't understand ...

don't you plan your dive ? You really need to be assisted for choosing the gaz in the list ?
do you really need 3 bottom gaz and 5 deco gas for a 120m dive ?

Some examples for a 120m/12mn dive :
bottom 10/65, travel TX 18/50, TX 30/35, Deco NX 50, OXY
3 bottom or travel, 2 deco
or
bottom 11/58, travel TX 21/35, Deco NX 50, OXY
2 bottom or travel, 2 deco

i think that 5 gaz for OC dive is enough !

[scubatinoo]

Hi

Bardass Wrote:
-------------------------------------------------------
> don't you plan your dive ? You really need to be
> assisted for choosing the gaz in the list ?

I agree totally with you. I know when to switch to which
gas. BUT... OSTC could help me switching the gas faster on the
computer for the further deco calculation!


> do you really need 3 bottom gaz and 5 deco gas for
> a 120m dive ?
> i think that 5 gaz for OC dive is enough !

No, me in my case i'm absolutely happy with 5 gases.
But i just don't like any better gas warning during
descend, recommending some deco gases... Of course i
can turn off this "warnings" - but on the other side
i would like to have the way to switch gases on the
computer (!!) more easier then pressing several buttons...

[DiverM]

Deco calculation including the travel gas might save five minutes of stops on the way up? And then only on the really deep and short(!) dives?
If you really want to, you can switch gasses on the OSTC during descent, the OSTC will then calculate tissue saturation with actual gas used. Or just go for the kludge, adding some extra safety.

@scubatinoo:
Maybe enhance the blink better gas with "gas preselect" in the list? ie: When reaching the set switching depth (plus/minus a margin of one meter?), the menu arrow is in front of the gas that is being 'blinked' as the better gas?

And maybe also make the blink better gas feature direction dependent? On descend blink for better gas dependent on PO[sub]2[/sub]? ie: when reaching the set max PO[sub]2[/sub] minus 0.2bar?

Edit: more thoughts.

[PeJo]

DiverM Wrote:
> Maybe enhance the blink better gas with "gas
> preselect" in the list? ie: When reaching the set
> switching depth (plus/minus a margin of one
> meter?), the menu arrow is in front of the gas
> that is being 'blinked' as the better gas?

@DiverM: Isn't that what Mathias has been working on in the coming FW?
read.php?2,9688

Or did I misunderstand you?

[DiverM]

@PeJo:

Quite possible, haven't tested the latest development software. But as I understood (or misunderstood ) the development it is only about highlighting the better gas?

[scubatinoo]

DiverM Wrote:
-------------------------------------------------------
> @scubatinoo:
> Maybe enhance the blink better gas with "gas
> preselect" in the list? ie: When reaching the set
> switching depth (plus/minus a margin of one
> meter?), the menu arrow is in front of the gas
> that is being 'blinked' as the better gas?

Something like that, yes.

[DTR.Diver66]

Hello All,

you're right. 5 gases for OC and 5 diluent gases for CCR are enough. But it would be nice to have 3 bottom gases and 2 deco gases in different lists or names, eg: B1-B3 for bottom gases and D1-D2 for the deco gases, then we could also set various ppO2 values for bottom gases and deco gases.


Regards

[DiverM]

DTR.Diver66 Wrote:
-------------------------------------------------------
> Hello All,
>
> you're right. 5 gases for OC and 5 diluent gases
> for CCR are enough. But it would be nice to have 3
> bottom gases and 2 deco gases in different lists
> or names, eg: B1-B3 for bottom gases and D1-D2 for
> the deco gases, then we could also set various
> ppO2 values for bottom gases and deco gases.
>
>
> Regards


IIRC a per gas pPO[sub]2[/sub] setting was suggested, and if I recall even better, this is on the to-do list for a future firmware.

That said, a per gas pPO[sub][sub]2[/sub][/sub] is a "nice to have" and the are other more pressing changes pending. I think...B)-