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Hi all,
On a number of occasions visitors to my gear site have commented on my use
of a single first stage suggesting that a dual outlet valve (like a
H-valve) would be a better alternative for single tank diving. The GUE
gear site too seems to encourage the use of H valves. I will soon
(hopefully, on order for over a month) have a new Apeks first stage to
replace the Scubapro MK10 I'm using at present. The hose layout for a
single Apeks first stage would not be as optimal as my present layout...
http://www.scu.edu.au/staff_pages/shartley/projects/gear/first_s.jpg
....because the Apeks firsts lack a LP port on the base (hoses would stick
out to the sides and possibly make it harder to reach my tank valve if the
need arises). This has got me thinking about H valves (I could configure
the hoses like a doubles rig and it probably wouldn't cost me too much to
set up). I was wondering what folks thought? Here are a few Pro' and
Con's of H valves that occur to me...
Pro's:
1) Would help with second stage free flows, O-ring or hose failures by
turning off the offending regulator (although I use unbalanced second
stages, not so prone to free flow, replace hoses regularly and use DIN
valves which secure O-rings better than yoke).
2) Optimal hose placement for non swivel Apeks first stages (although on
the Scubapro valves the second valve (left) is fairly low down, yet to see
how well this would work).
Con's:
1) May forget to turn on both valves (meaning the pressure guage may not
indicate the actual tank pressure, I know I should notice this, and I am
usually pretty pedantic about this sort of thing).
2) More complex setup (although I'd doubt there'd be any extra drag, still
prefer keeping things simple).
3) Greater entanglement risk (with extra valve knob sticking up from the
top of the valve).
4) Extra O-rings (although the plug in the valve already has an O-ring and
the second valve and first stage can be shut off).
5) May muck around trying to shut down one valve or the other instead of
getting to a buddy or the surface when the shit hits the fan.
6) Still doesn't help with say a ruptured neck O-ring or a burst disk blowing.
7) Would need to install H valves on all tanks I use or change setup for
travel (not a biggie, I already use DIN which is not common in Aus).
I have seen comments in the past but no luck finding anything useful in the
archive. Any comments appreciated.
Cheers,
Simon
Simon L Hartley
RSM Website Coordinator\First Year Course Coordinator
Associate Lecturer
School of Resource Science and Management
Southern Cross University
P.O. Box 157
Lismore NSW, Australia 2480
Ph: (02) 66203251 or (61 66) 203 251
Fax:(02) 66212669
E-mail: shartley@sc*.ed*.au*
http://www.scu.edu.au/staff_pages/shartley/index.html
http://www.scu.edu.au/schools/rsm/
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