Allow user to select dive mode (including PSCR)

[Davide DB]

On Mon, Jan 19, 2015 at 1:02 PM, Anton Lundin <glance at acc.umu.se> wrote:
>
> Hmm... As i read http://www.halcyon.net/RB80 it says
> "8:1 ratio provides substantial gas extension"
>
> Is that old info or should i read that in some other way?

Counterlung ratio is 1:10, 8:1 is the real expected ratio in water due
to mask clearing, ascent flush...

http://www.frogkick.nl/files/michael_waldbrenner_rb80_rebreather.pdf (page 10).

This is another article form the RB 2000 inventor Dr. Reinhard Buchaly:

http://www.diritalia.it/images/pdf/quest/buchaly_rb80.pdf

Unfortunately it's in Italian but you can easily translate with google:

La ventilazione di questo rebreather semi chiuso a volume costante ha
una ratio di 1:10 (page 2)
La resa effettiva è di 1:8. Lo scarico del corrugato, profili yo-yo
che frequentemente si trovano nelle grotte e l'espirazione dal naso
non permettono di raggiungere la ratio ideale. (page 3)

I was taught to use factory counterlung ratio.






>> > another question: With a pSCR it could be possible to get into a low pO2
>> > situation, so in planning a dive we should warn in that case as we do for
>> > high pO2. Which value is the minimal acceptable? Wikipedia mentions 0.16bar.
>> >
>>
>> Yes the O2 drop effect bring to have a MiOD (Minimum Operative Depth)
>> for every gas.
>> 0,16 is minimum PO2 to sustain life. Usually all tables reports MiOD
>> for 0,16 and 0,21.
>>
>
> 0.16 Is a good warning limit, but you should be really careful with such
> low po2's. Don't try to walk stairs, or climb a ladder breathing that.
>
> You can do a bit of work breathing such a low po2, if you're
> acclimatized to it, ex. skiing in the alps, but its quite tiresome.

Of course 0,20 0,21 is the safe limit neverthless a lot of tables
reports both limits. As 90% of info displayed by Subsurface they
should be used with a grain of salt and from trained people.


-- 
Davide
https://vimeo.com/bocio/videos