In message <34CDCCAB@uk*.uk*.se*.co*>, "David Shimell (shimell)"
<shimell@se*.co*> writes
>
>Chris
>
>Thanks for taking the time to reply.
>
>>Firstly, deco cylinders without gauges will bite your ass one of these
>>days (ask Martin Smith about that one). The arguament of an extra
>>failure point usually rears it's ugly head in discussions like this.
>>From most folks experience, a proper stage regulator set up (gauge not
>>flapping in the wind) is about as reliable as the rest of your stuff.
>
>I'm not aware of that particular Martin Smith incident.  The procedure I   
>apply works but if I became complacent it would fail, just as if I get   
>complacent about gas planning or any other aspect of my diving.  You will   
>be glad to hear that it is not in my nature to be complacent!  I agree   
>with your point that the likelihood of a short, tidy HP hose failing is   
>low, but my point is that it is avoidable.  HP hoses do fail.  I have had   
>a standard length HP hose blow on the boat as I was about to kit up.   
> This hose was about 12 months old and on inspection in apparently good   
>condition.  Being anal, I check my hoses every few dives.  I have seen a   
>HP hose go one other time but this was in poor condition and should never   
>have been near the water.  I do not fret about using a HP hose since I   
>use one on my backup regulator on my twinset and I will use a 7" hose on   
>a stage bottle when I need to dive thirds.  I do not use them on my deco   
>bottles as I do not need them therefore I do not take them in the water.
>
>>If the justification for not having a gauge is substantiated by having a
>>buddy to run to if 'shit happens' (incidentaly, after 20 years of diving
>>and servicing dive gear the only times I have seen a neck O ring fail is
>>down to poor maintenance) then I cannot see any application for a twin
>>set and a 3l 'stage bottle'.
>
>You are being slightly emotive WRT "buddy to run to", but I agree with   
>your point.  Here we have shifted (I started it!!) from the original   
>discussion of single with pony to twinset with 3l stage.  The application   
>is simply one of using the 3 l cylinder to carry deco gas.  The twinset's   
>redundancy allows more adventurous diving whilst the pony carries the   
>deco gas.  In this instance my gas planning would be such that I can   
>ensure that I can meet my deco obligations with *either* my back gas *or*   
>my 3l deco bottle thus maintaining a redundant configuration and supply.   
> Since I quite rightly got grief about apparently mis-representing BSAC   
>training - which I hope was due to lack of clarity in my writing rather   
>than my understanding, I will emphasise that the 3l cylinders are being   
>used for entirely different purposes here.  With a single it is used as a   
>bailout from depth and so the contents must be breathable from the   
>maximum planned depth. In the twinset and small deco cylinder scenario,   
>it is just another deco bottle and the "standard" rules of gas planning   
>and management of deco bottles apply.
>
>I'm starting to get bored with this discussion how about you?
>
>Dave

Yup!


Regards

 
Chris Hellas         e-mail - chris@de*.de*.co*.uk*
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