Re: Dive planner MG, TP and FC

[Ivan Wagner]

I think there are two main applications here:

1. for tracking data with the current planner which calculates
everything in detail for every dive sample.
2. for bottom timer users which want to have an idea of the plan thus
calculations are really easy by just adding parameters such as stops,
SAC rate, depth and so on.

These are two different approaches. One gets integrated in today's
subsurface planner, and the other one could be a easy to use custom
calculator (like a normal math calculator) and it would be easy to
implement.

What do you think?

Ivan
On 10/14/2015 04:34 PM, Willem Ferguson wrote:
> On 14/10/2015 16:28, Willem Ferguson wrote:
>> On 14/10/2015 16:05, Robert Helling wrote:
>>> Hi,
>>>
 On 14.10.2015, at 15:26, Willem Ferguson
  wrote:

 This is the gas pressure in the cylinder at the start of the ascent
 phase? This is a meaningful request but would require another selection
 to be made in the planner (gas turn rule). This is something that I use
 all the time in dive planning.
>>>
>>> what would that mean for the planner? Except for recreational mode,
>>> the planner always starts the ascent at the end of the manually
>>> entered waypoints.  Would you want to say something like “go to 80m
>>> and then figure out the pressure at which you have to leave 80m so
>>> you and your buddy make it to the surface with x bars remaining”?
>>>
>>> Best
>>> Robert
>>>
>>> -- 
>> Robert,
>>
>> Correct.
>>
>> Of course, actually, I commonly dive 230 bar and start the ascent at
>> around 90-95 bar, using thirds. So the 77 bars accurately constituting
>> a third is really a bare minimum and it is affected by deco
>> obligations.  But a message indicating "Ascent back gas pressure = 90
>> bar, i.e. within rule-of-thirds pressure (77 bar)" would be helpful.
>> It is an additional bit of safety information that checks the accuracy
>> of the deep section of the overall dive planning outside of
>> Subsurface. Does this make any sense?
> Of course you can see Ferguson' muddled mind here. In a strict thirds
> approach turning would be at around 140 bars in a cave. Reason for every
> bit of additional safety information from the planner. Fortunately I do
> not put my foot in a cave, otherwise I might consider turning at 90 bar!
> 
>> Kind regards,
>> willem
>>
>>
>>
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> 
> 
> 
> 
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Re: Dive planner MG, TP and FC

[Henrik Brautaset Aronsen]

14. okt. 2015 16.45 skrev "Ivan Wagner" :
>
> In fact I use the Shearwater Petrel as a bottom timer... a :D so
much
> money for a bottom time.

Hehe, same here. Allthough the latest firmware added a stopwatch and
resettable average depth in OC Tec mode,  so now the Petrel is even usable
as a computer ;)

Henrik
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Re: Dive planner MG, TP and FC

[Willem Ferguson]

On 14/10/2015 16:05, Robert Helling wrote:

Hi,

On 14.10.2015, at 15:26, Willem Ferguson 
> wrote:


This is the gas pressure in the cylinder at the start of the ascent
phase? This is a meaningful request but would require another selection
to be made in the planner (gas turn rule). This is something that I use
all the time in dive planning.


what would that mean for the planner? Except for recreational mode, 
the planner always starts the ascent at the end of the manually 
entered waypoints.  Would you want to say something like “go to 80m 
and then figure out the pressure at which you have to leave 80m so you 
and your buddy make it to the surface with x bars remaining”?


Best
Robert

--

Robert,

Correct.

Of course, actually, I commonly dive 230 bar and start the ascent at 
around 90-95 bar, using thirds. So the 77 bars accurately constituting a 
third is really a bare minimum and it is affected by deco obligations.  
But a message indicating "Ascent back gas pressure = 90 bar, i.e. within 
rule-of-thirds pressure (77 bar)" would be helpful. It is an additional 
bit of safety information that checks the accuracy of the deep section 
of the overall dive planning outside of Subsurface. Does this make any 
sense?

Kind regards,
willem

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Re: Dive planner MG, TP and FC

[Willem Ferguson]

Robert,

Can a make a second attempt to make more sense? But this is, I am sure, 
boring to you.


The group that I do deep dives with use a thirds approach: whether you 
dive caves or open water and nothing goes wrong, diver needs a third of 
the back gas remaining at the end of the dive. So, given SAC rate(s) it 
is simple (but sometimes tedious) to calculate the cylinder pressure at 
which ascent starts. But ascent pressure is not merely a third, diver 
and buddy must be able to get to 1st cylinder change depth, so this 
amount is added to the cylinder pressure value of a third. This often 
gives ascent start pressures between 80 and 100 bar. It would be useful 
if this pressure at start of ascent were calculated by Subsurface. The 
reason why this number is useful is of course when one underestimates 
SAC for that particular dive and the bottom time should be shortened 
because of remaining back gas requirement. This number goes on my slate 
every dive, therefore the usefulness. Do I make sense at all this time 
round? Good communication is difficult.

Kind regards,
willem

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Dive planner MG, TP and FC

[Ivan Wagner]

Dear list,

I was taking a look at the dive planner feature within subsurface and I
see some useful features that could be added:

- Minimum gas (based on a scenario of an out-of-gas event and and ascent
respecting ascent rates, deep stops etc)
- Turn pressure based on gas rule such as all usable, half usable or
rule of thirds
- Fractional consumption at depth with 5 minutes interval.

This is something I use on a daily basis not only for technical dives
but also recreational dives.

Could this be interesting for you? I could implement something.

Let me know,

ivan


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Fwd: Re: Dive planner MG, TP and FC

[Willem Ferguson]

Ivan, Robert,

I think I understand the request.

On 14/10/2015 14:21, Ivan Wagner wrote:

Dear list,

I was taking a look at the dive planner feature within subsurface and I
see some useful features that could be added:

- Minimum gas (based on a scenario of an out-of-gas event and and ascent
respecting ascent rates, deep stops etc)


The planning takes into account all gas available and subtracts the
amounts required for gas sharing as well as a 'residual' amount that
needs to remain. If one requires 50 bar for buddy-sharing (calculated by
the planner automatically) and another 30 bar residual was requested on
the dive planner form, the minimum gas use at the end of the dive is
start-pressure minus 80 bar. So the concept of minimum gas required is
not really relevant here, at least for recreational dives.


- Turn pressure based on gas rule such as all usable, half usable or
rule of thirds


This is the gas pressure in the cylinder at the start of the ascent
phase? This is a meaningful request but would require another selection
to be made in the planner (gas turn rule). This is something that I use
all the time in dive planning.


- Fractional consumption at depth with 5 minutes interval.


There is a continuous trace of the gas pressure throughout the dive and
the precise pressure can actually be read from the profile information
box (the moving black box on the profile panel). Would fractional gas
information really give one more useful insight?


This is something I use on a daily basis not only for technical dives
but also recreational dives.

Could this be interesting for you? I could implement something.

Let me know,

ivan



Kind regards,
willem



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