[PATCH]Re: Deco calculation for repetitive dive - strange effect

[Rick Walsh]

On 10 February 2017 at 07:50, Stefan Fuchs <sfuchs at gmx.de> wrote:

>
>
> 3. Then for the second, much simpler dive I am surprised that the results
> are different! I planned this very simple dive then "standalone" in both
> tools -> still the same difference. VPlanner gives you shorter deco and I
> really have doubts if I did s.th. wrong but I can't figure out what.
>
> Subsurface Tauchplan
> Runtime: 55min
>
> Tiefe
>
> Dauer
>
> Laufzeit
>
> Gas
>
> ➘
>
> 40m
>
> 4min
>
> 4min
>
> Luft
>
> ➙
>
> 40m
>
> 16min
>
> 20min
>
>
>
> -
>
> 15m
>
> 6min
>
> 26min
>
>
>
> -
>
> 12m
>
> 3min
>
> 29min
>
>
>
> -
>
> 9m
>
> 4min
>
> 33min
>
>
>
> -
>
> 6m
>
> 7min
>
> 40min
>
>
>
> -
>
> 3m
>
> 12min
>
> 52min
>
>
>
> ➚
>
> 0m
>
> 3min
>
> 55min
>
>
>
>
> CND: 9%
> OTU: 24
>
> Deco model: VPM-B at +2 conservatism, effektive GF=27/66
> ATM pressure: 1013mbar (0m)
> V-Planner 3,98 by Ross Hemingway,
> VPM Code by Erik C. Baker.
>
> Dekompressionsmodell:  VPM - B
>
> TAUCHPLAN
> Oberflächenpause = 5 Tag(e) 0 hr 0 min.
> Höhe über N. N. = 0m
> Konservatismus = + 2
>
> Abst.    40m        (4)    Air    10m/min Abstieg
> Tiefe    40m     16:00    (20)    Air    1,02  ppO2,  40m ead
> Aufst.    18m        (22)    Air    -10m/min Aufstieg
> Stop    18m      0:48    (23)    Air    0,58  ppO2,  18m ead
> Stop    15m      2:00    (25)    Air    0,51  ppO2,  15m ead
> Stop    12m      3:00    (28)    Air    0,45  ppO2,  12m ead
> Stop    9m      3:00    (31)    Air    0,39  ppO2,  9m ead
> Stop    6m      7:00    (38)    Air    0,33  ppO2,  6m ead
> Stop    3m     10:00    (48)    Air    0,27  ppO2,  3m ead
> Oberfl.            (51)    Air    -1m/min Aufstieg
>
> Ausgasung beginnt bei  27,4m
>
> OTU's Tauchgang: 21
> CNS Total: 7,4%
>
>
> I'm no German speaker, but I guess Oberflächenpause is surface interval.
Can you try planning this dive again with V-Planner, but do it as a new
'mission', rather than a 5 day surface interval?  In Subsurface, we ignore
any previous dives >2 days earlier, but V-Planner may not, and it may be
taking credit for the crushing pressure of the previous dive.

>
> Finally I decided not to worry too much :-)
> - I prefer to see a penalty for any repetitive dive I plan so I like the
> fix you did now
> - Subsurface at least in this examples gives similar or slightly more
> conservative results -> also ok for me
> - My buddies and me will continue to compare different results before we
> go diving
> - I don't do repetitive dives so often because actually I'm too lazy to
> get in and out of my dry suit more than once a day + plus I'm so hungry and
> thirsty after each dive that this also stops me from doing a second one
> afterwards ;-)
>
>
> Best regards
> Stefan
>
> --
>
> Stefan Fuchs
> E-Mail: sfuchs at gmx.de
>
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