Recreational planning with Subsurface?

[Rick Walsh]

On 25 Jan. 2018 9:34 pm, "Robert Helling" <helling at atdotde.de> wrote:

Willem,

On 25. Jan 2018, at 10:48, Willem Ferguson <willemferguson at zoology.up.ac.za>
wrote:

Hi Willem,
In the example you provide, the air NDL at 30m is 13min with gf 35/75. This
looks about right to me. From memory the Buhlmann NDL (gf 100/100) is
~17min, and the PADI and navy tables are 2-3 minutes longer. Reducing the
gf to 35/75 would reduce the NDL.


I suspect this is not the complete explanation. The NAUI, NOAA and US Navy
tables all give the NDL with air at 30m between 22 and 25 min. With
gf=100/100, Subsurface gives 16 min. In addition, the profile does not get
close to the ceiling at NDL. I suspect that, with initial cyl pressure not
specified, the whole calculation just does not work. Forcing the bottom
time to 26 min (gf=100/100) brings the ceiling close to the profile which
is more or less acceptable. So that part of the planner works. But if the
bottom time is specified as much shorter than 26 min, the NDL also is much
shorter. There is a problem or bug there.


how to you get the 16min from Subsurface? Because I seem to get 23min with
GF 100/100:

I dare say the difference is due to your different ascent and descent rates



Best
Robert

-- 
.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.
oOo.oOo.oOo.oOo.oOo.oO
Robert C. Helling     Elite Master Course Theoretical and Mathematical
Physics
                      Scientific Coordinator
                      Ludwig Maximilians Universitaet Muenchen, Dept. Physik
                      Phone: +49 89 2180-4523 <+49%2089%2021804523>
 Theresienstr. 39, rm. B339
                      http://www.atdotde.de

Enhance your privacy, use cryptography! My PGP keys have fingerprints
A9D1 A01D 13A5 31FA 6515  BB44 0820 367C 36BC 0C1D    and
DCED 37B6 251C 7861 270D  5613 95C7 9D32 9A8D 9B8F
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.subsurface-divelog.org/pipermail/subsurface/attachments/20180125/1adb69da/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Screenshot 2018-01-25 11.34.19.png
Type: image/png
Size: 168123 bytes
Desc: not available
URL: <http://lists.subsurface-divelog.org/pipermail/subsurface/attachments/20180125/1adb69da/attachment-0001.png>