Can anyone explain why I have a deco ceiling on this dive? I never hit my NDL and after reading the FAQ I'm even more confused. 
Subsurface Deco Ceiling Question
- Thread starter unwantedsn
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What computer are you using?
Shearwater Teric @Marcellus ( bottom of page) it looks likely steady dive. Plenty of bottom time.... Strange. K
Griffo
Contributor
I believe it just takes it from the computer, in which case the "safety stop" in rec mode may be reported as the deco ceiling. Is your Teric set to a 10ft safety stop? (I think it's called last stop)
Correct me if I am wrong, but Shearwater computers (at least Perdix and Teric) do not account for safety stops in their NDL calculation (which makes perfect sense if you ask me). I am only using OC Tec mode, but I am 99% sure it's the case for OC Rec as well.
It looks like the leading tissue has a 'ceiling' (shown in green) but would be cleared on your way up before you hit it, so you were not informed about it.
You can try this yourself in the planning mode:
Try 90ft dive on air for 12 mins at GF40/85. You will see a "ceiling", but you clear it on the way up (following recommended speed). Now click on the right bottom point right before ascend and drag it more to the right side. At one point, the ascent line and the ceiling would meet - and the ascent line would flatten out for few mins at 3/6m (depending on your setting) - mandatory deco stop.
It looks like the leading tissue has a 'ceiling' (shown in green) but would be cleared on your way up before you hit it, so you were not informed about it.
You can try this yourself in the planning mode:
Try 90ft dive on air for 12 mins at GF40/85. You will see a "ceiling", but you clear it on the way up (following recommended speed). Now click on the right bottom point right before ascend and drag it more to the right side. At one point, the ascent line and the ceiling would meet - and the ascent line would flatten out for few mins at 3/6m (depending on your setting) - mandatory deco stop.
No, Teric manual only mentions "last stop" setting in connection to deco stops:
By default, the Teric uses a 3m (10ft) last stop depth. At this setting, you may perform the last stop at 6m (20ft) with no penalty. The only difference is that the predicted time-to-surface will be shorter than the actual TTS since off-gassing is occurring slower than expected. There is also an option to set the last stop to 6m (20ft) if you wish.¨
Safety stops, on the other hand, happen at fixed depth:
Once the depth exceeds 11m (35ft), a safety stop will be required. An alert will occur when in the safety stop depth range, shallower than 6m (20ft). [...] If the depth goes outside of the range 2.4m to 8.3m (7ft to 27ft), then the countdown pauses, and the remaining time displays in yellow
You probably had different GF settings on your computer.
You can toggle computer displayed ceiling on/off in subsurface, should work with teric (works with perdix).
I your screenshot you seem to have really minimal actual ceiling, so even if you have the same gf settings there may be small differences in the implementation of the algorithm.
Usually subsurface and shearwater are really close.
You can toggle computer displayed ceiling on/off in subsurface, should work with teric (works with perdix).
I your screenshot you seem to have really minimal actual ceiling, so even if you have the same gf settings there may be small differences in the implementation of the algorithm.
Usually subsurface and shearwater are really close.
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