VR3 variable ceiling indicator

Gregv · 16th September 2006, 20:44

Apologies if this has been asked recently, I've trawled the archives and the manual and can't find an explanation for how the VR3 (standard C4 Buhlmann v3.03a) computes the variable ceiling indicator (diver on the line) at the last stop.

During most stops it performs as I expect it to - the indicator appears only when I get within 3m of a decompression stop and it shows the proximity of the next stop. When the diver gets to the top of the line, your depth equals that of the current decompression stop.

However I have noticed on longer dives while I am hanging at 6m, the variable ceiling indicator slowly gets shallower, permitting me to ascend through to 5, then 4 and later 3m before my stops clear. The deepest stop field continues to show 6m. Nowhere is this behaviour explained in the manual. I havent tried setting the last stop to 3m yet and seeing if the final stop 'drifts' shallower over time there as well. Perhaps the deepest stop setting is just a software fudge and the profile always computed using a 3m final stop?

Not a big deal, since the difference in deco is virtually nil, but I'm curious. Anybody experimented with this further and have some wise words to add to my ramblings?

Greg

mbelair · 16th September 2006, 22:37

Your variance on deco will get longer as your deco obligations increase.
From what I understand, the dive plan is calculated for a profile follwing the man-on-the-line.

The man on the does bring you gradually up to the next stop. It does so BEFORE the shallower stop appears. Take it as a variable ceiling more than a true stop.

Gilles · 16th September 2006, 23:17

Quote: (Originally Posted by Gregv)

However I have noticed on longer dives while I am hanging at 6m, the variable ceiling indicator slowly gets shallower, permitting me to ascend through to 5, then 4 and later 3m before my stops clear. The deepest stop field continues to show 6m. Nowhere is this behaviour explained in the manual. I havent tried setting the last stop to 3m yet and seeing if the final stop 'drifts' shallower over time there as well. Perhaps the deepest stop setting is just a software fudge and the profile always computed using a 3m final stop?

Not a big deal, since the difference in deco is virtually nil, but I'm curious. Anybody experimented with this further and have some wise words to add to my ramblings?

Greg

Greg;

I have the older version (V2.1 CXR) and I believe if you set your shallow stops shallower, the only difference you'll see is a changed deco forecast. Your actual deco won't change and will depend on where in your variable ceiling you stay. My pref is to start at the bottom of the ceiling and slowly make my way to the top so that I'm there when the level is clear. On rough seas, I'll stay at 4.5-6m until it gets cleared (rather than go to 3m).

G

16th September 2006, 20:44	#1 (permalink)
Gregv New Member Current Rebreather/s: Megalodon Dolphin Ray Home Build Other Rebreather/s: Dolphin Ray Home Build Join Date: May 2005 Location: Whangarei, New Zealand Posts: 30	VR3 variable ceiling indicator Apologies if this has been asked recently, I've trawled the archives and the manual and can't find an explanation for how the VR3 (standard C4 Buhlmann v3.03a) computes the variable ceiling indicator (diver on the line) at the last stop. During most stops it performs as I expect it to - the indicator appears only when I get within 3m of a decompression stop and it shows the proximity of the next stop. When the diver gets to the top of the line, your depth equals that of the current decompression stop. However I have noticed on longer dives while I am hanging at 6m, the variable ceiling indicator slowly gets shallower, permitting me to ascend through to 5, then 4 and later 3m before my stops clear. The deepest stop field continues to show 6m. Nowhere is this behaviour explained in the manual. I havent tried setting the last stop to 3m yet and seeing if the final stop 'drifts' shallower over time there as well. Perhaps the deepest stop setting is just a software fudge and the profile always computed using a 3m final stop? Not a big deal, since the difference in deco is virtually nil, but I'm curious. Anybody experimented with this further and have some wise words to add to my ramblings? Greg
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16th September 2006, 22:37	#2 (permalink)
mbelair RBW Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jan 2006 Location: Montreal Posts: 83	Re: VR3 variable ceiling indicator Your variance on deco will get longer as your deco obligations increase. From what I understand, the dive plan is calculated for a profile follwing the man-on-the-line. The man on the does bring you gradually up to the next stop. It does so BEFORE the shallower stop appears. Take it as a variable ceiling more than a true stop. __________________ Marc
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16th September 2006, 23:17	#3 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 762	Re: VR3 variable ceiling indicator Quote: (Originally Posted by Gregv) However I have noticed on longer dives while I am hanging at 6m, the variable ceiling indicator slowly gets shallower, permitting me to ascend through to 5, then 4 and later 3m before my stops clear. The deepest stop field continues to show 6m. Nowhere is this behaviour explained in the manual. I havent tried setting the last stop to 3m yet and seeing if the final stop 'drifts' shallower over time there as well. Perhaps the deepest stop setting is just a software fudge and the profile always computed using a 3m final stop? Not a big deal, since the difference in deco is virtually nil, but I'm curious. Anybody experimented with this further and have some wise words to add to my ramblings? Greg Greg; I have the older version (V2.1 CXR) and I believe if you set your shallow stops shallower, the only difference you'll see is a changed deco forecast. Your actual deco won't change and will depend on where in your variable ceiling you stay. My pref is to start at the bottom of the ceiling and slowly make my way to the top so that I'm there when the level is clear. On rough seas, I'll stay at 4.5-6m until it gets cleared (rather than go to 3m). G __________________ Gilles http://www.dirrebreather.com
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