Subsurface mobile general question

[Robert Helling]

Hi Willem,

thank you for your comments.

> On 15. Nov 2021, at 08:18, Willem Ferguson via subsurface <subsurface at subsurface-divelog.org> wrote:
> 
>> 
>> I meant more the other way around: If you diluent also contains O2, you underestimate the O2 consumption if you only use the pressure drop in the O2 cylinder.
> The O2 consumption under CCR is not a dive characteristic because the diver can bail out to OC. So O2-consumption would be a cylinder-level characteristic, associated with cylinder 0 ?? (i.e. the diluent cylinder because as far as I can remember the O2 cylinder does not explicitly exist in the Subsurface CCR dive log). In pSCR bailout is often part of the normal dive procedure during deco.
> 
Bailout is of course a special case. And yes, it should be handled dive segment by dive segment like an OC dive with several cylinders.

PSCR is again a completely different thing. I would argue it’s closer to OC as the absolute consumption is also depth dependent. Are there any significant number of divers still using those? All I knew personally moved on to CCR. I don’t really know about how Subsurface handles the two types of cylinders for a CCR. Amongst those dives we use for testing is test40.xml which is a CCR dive with both an air diluent as well as oxygen cylinder and gas is used from both. I don’t know if that is typical. Do we have magic cylinder numbers like 0 that indicate diluent? I wasn’t aware of that.

>> 
>> So here is a question I have: For a typical CCR dive, what is the ratio between used O2 and used diluent? I understand this depends on how often descend and how often you flush but what is a ballpark type figure?
>> 
> As a ball park approximation, many CCR dives (up to 65m) are done using air as a diluent, supplemented with oxygen from the O2 cylinder to make up for oxygen consumed as well as for higher O2 levels during shallower deco.
> 
> 

But what is the ratio of diluent use to O2 use? That test dive uses 123 liters of O2 and 100 liters of air.

Best
Robert
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.subsurface-divelog.org/pipermail/subsurface/attachments/20211115/168d42c0/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: Message signed with OpenPGP
URL: <http://lists.subsurface-divelog.org/pipermail/subsurface/attachments/20211115/168d42c0/attachment-0001.sig>