Two more rebreather patches

William Perry wmperry at kadath.us
Mon Oct 27 08:29:47 PDT 2014


> On Oct 27, 2014, at 10:42 AM, Rodrigo Severo <rodrigo at fabricadeideias.com> wrote:
> 
> On Mon, Oct 27, 2014 at 12:37 PM, William Perry <wmperry at kadath.us> wrote:
>> 
>> I just finished  by CCR training down in Bonaire last week so I don’t have a
>> lot of experience, but I did find that minor depth changes did not impact
>> the loop volume enough for me to feel the need to add diluent.  My inhale
>> was cut very slightly short (I was diving with the auto-diluent-valve off
>> after the initial big descent).  This would be equivalent to the occasional
>> mask clear at depth.  If you are doing a ton of 10 meter ascents/descents in
>> a cave system as it winds around then those will add up quickly, but 1-2
>> footers is noise.
> 
> Bill,
> 
> 
> I agree: 1/2 foot is noise, 10 m is significant.
> 
> What value do you think we should use as limit? I just proposed 1 m on
> my previous email to Robert but I'm not sure if this value is big
> enough.
> 
> What do you think?

Maybe start tracking it if they stay at the new depth for more than a certain # of samples?  If I just drop down quickly to look at something I’m not going to mind a short breath or two but if I am following the contour of the reef and stay at that depth for 5-10 minutes I will probably squirt in some diluent.  I’m generally not a fan of heuristics like that though.

>> Would tracking only the size of the counter lungs be sufficient?
> 
> I don't think any of this is necessary, neither counter lungs volume
> nor loop volume as I mentioned on my previous email.

Yes, if we are just worrying about determining a SAC rate after the fact.  Would some indication of loop volume help for planning these dives though?

-bill


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