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> geeze Tom (obie one) i expected more from you than this.. are you
> connected in any way with the odessey?  of course there have been changes
> in the electronics and other technology along the way.. hell this is the
> 90's.  I sorta got the same comments, or questions from rich privately, 
> (good one's really, but come on you guys, do you think we are really all
> that stupid).

Sometimes I wonder ;-)

Seriously, though, my only point was this:  You can have new technology,
or 3.5 million hours of testing, but not both.  The value of the testing
is in finding failure points.  There is a diminishing returns at some
point where you no longer find new failure points, and only get a more and
more accurate idea of failure *rates*.  Now, when you have this
information (failure points and rates of failure), then the smart thing to
do is correct the failure points which have the highest frequency
(balanced against some measure of cost of failure) by re-designing the
relavent components. Once you've re-designed them, though, the "testing
hours" clock gets reset to zero for those components in the system.  So,
either the CCR500 is exactly the same as the CCR1000 (3.5 million hours of
testing, but old technology), or the most frequent failure points have
been re-designed (new technology, but considerably less than 3.5 million
hours of testing). Again, you can't have it both ways. 

I guess my only suggestion is, instead of saying things like "every 
component has had more than 3.5 million hours of testing" (as I think was 
an assertion made at the start of this thread), you should say something 
like "is the latest in the BioMarine line of rebreathers, which 
collectively have on the order of 3.5 million hours of testing".  That 
way you can make the point that a lot of people have spent a lot of time 
on the *predecessors* of the CCR500, and to a greater or lesser extent 
the discoveries made during all that testing have gone into improving the 
CCR500 design.  Presumably, then, the *wisdom* obtained from all that 
testing has been transferred to the new design, with the incorporation of 
the latest technology.

I'm looking forward to seeing these things up close & personal.  There 
should be two Cis-Lunar Mk5's in Hawaii in August - maybe we can schedule 
a session in the UH pool for some side-by-side comparisons?

> I can't believe you even brought this up... either one
> of you...  and one more point, for everyone out there.. this ccr stuff is
> not magic, it't not even that complicated, so let's stop trying to make
> everyone that doesn't have a unit think that we are smarter or better than
> they are.. anyone out there could (and will) dive one easily.

What's your point, and who are you addressing it to?

> i don't want to hurt anyone's feelings, but i do not, and will not ever,
> understand why anyone would build a semiclosed unit..  if anyone buys
> one of these units they will be trying to trade it or sell it so they can
> get a fully closed unit..  it's happening already...

I imagine that people would opt for a SCR (at least a passive-addition
system like the Odessey) because they don't want to put in the amount of
training required to become disciplined enough to consistently stay alive
on a fully-closed unit.  I agree in basic principle with you on the SCR -
except for being quieter, I'm not sure I see the advantages over a set of
double nitrox cylinders.  However, don't underestimate the amount of
dedication it takes to consistently stay alive on a fully closed unit. 
The fundamental reason why they require more discipline is that you can
more easily die before you realize anything is wrong. Furthermore, you're
more likely to go hypoxic on a SCR in shallow water, whereas you are more
likely to go hypoxic on a CCR in *deep* water. Also, you only go hyperoxic
on an SCR if you exceed the depth limits.  You can go hyperoxic on a CCR
at any depth greater than about 20 feet.  No, it's not a magic carpet, and
it's not rocket science.  But it sure as hell isn't scuba diving either. 

Rich

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