User manual inconsistencies: dive planner

Willem Ferguson willemferguson at zoology.up.ac.za
Mon Aug 4 05:07:33 PDT 2014


On 04/08/2014 13:20, Sergey Starosek wrote:
> Willem,
>
> Two questions regarding user manual:
>
>  1. In "Oxygen management" you use both 1.5 and 1.6 maximum
>     allowed/deco pO2. Which one is correct? The default is ssrf is 1.6
>     bar.
>  2. You reference "mean depth" line in Planner but I don't see one.
>     Was it copy/paste from profile description? Or did it disappear
>     like axis guides?
>
> Sergey
>
>
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Sergey,

1. This answer is complex. My short response: I propose that this 
section of the user manual uses only PO2max of 1.5.  Long reponse: 
Usually, the Bottom PO2 is  1.4, while the Deco SAC is often 1.5, 
although I see that people who do deco with 100% oxygen actually use 
PO2(max) = 1.6 (6m max depth). The planner should follow the setup 
values under "Gas Options". In other words, if a PO2 for deco has been 
set at 1.6, then it should change at deco gas PO2=1.6. If one sets deco 
PO2 to 1.5, then it should change at a value of 1.5. However, I must 
admit that, with  deco PO2 set to 1.6 in a specific dive plan, the 
planner on my machine changes to the deco gas at a PO2 of 1.5. The most 
parsimonious way to write the manual is to assume that the planner 
changes gasses according to the setup values under 'Gas Options'. In the 
user manual there was no attempt to recommend any specific PO2 max 
value, only to give an indication of what appropriate PO2 max values 
could be. After all, this is a topic discussed at length during the 
training. The last sentence of the paragraph reads "Normally the planner 
decides on switching to a new gas when, during ascent, the partial 
pressure of the new gas has decreased to 1.6 bar.". I THINK that this is 
what Robert communicated to me at some stage but I am not sure. We need 
input from Robert here, especially since some of the user manual for the 
planner was written before the finalisation of the planner UI. To be 
safe, I would keep all PO2max values in the user manual to 1.5, even if 
one can set it higher in the planner setup values.

2. This one is easy. Short reponse: The line for mean depth disappeared 
with the redesign of the planner UI, as did the axis guide lines. Long 
reponse: Maybe this needs re-negotiation for V4.3 especially since many 
dive computers report "Average depth" during and/or after a dive. As far 
as I am aware mean depth has no relevance to formal dive planning, but 
only for interpreting the dive plan after the fact.
Kind regards,
willem

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