Jan, I was curious and had a peek at your github. I hope you don't mind. Robert's feedback is what you should be most interested in, but I'll give mine anyway. https://github.com/Slagvi/subsurface boyle
On 15 July 2015 at 06:31, Jan Darowski <jan.darow...@gmail.com> wrote: > Yes, I've seen this link first time you sent it. Parameters are not > the problem here. We have a different tissue saturation calculation > method, so results differ a little bit at the beginning of the ascent. > So the first stop is a little bit later (6m), It has a big influence > on the total deco time because later gradients are calculated against > this depth. > The first thing I noticed was that the critical radii for N2 and He were still 0.8 and 0.7 microns, which is the usual setting for VPM without Boyles law compensation. With Boyles law compensation, 0.55 and 0.45 microns are generally considered to be the nominal values (zero conservatism). This means that your model was being more conservative than V-Planner's most conservative (+4) setting, which increases the critical radii by 35%. It is not surprising you've been getting huge decompression times. After changing the critical radii, I compared the total ascent times to published results from V-Planner for 200ft and 300ft trimix dives. Links to pdf files are about 1/3 of the way down the page. http://www.decompression.org/maiken/VPM/VPM_Publications.htm Just looking at the total ascent time and depth of the first stop, the match is very good for the 200 ft dives in the 20-60min bottom time range (all total ascent times within 1minute, and appears to be the same first stop depth). This is impressive. For a 10min bottom time, Subsurface was 3min more conservative, and for >60min bottom time, Subsurface was progressively less conservative than the V-Planner profiles (e.g. 10min difference in ascent time for 120min bottom time). For the 300ft dives, Subsurface was less conservative than the V-Planner profiles. Could the differences for longer and deeper dives be due to the critical volume algorithm you mentioned you needed to investigate further? Cheers, Rick
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