At 05:50 PM 07/05/2001 -0400, Steve Schultz wrote:
>Greg,
>
>Y-valves only come in yoke, not DIN as far as I know.  You can get DIN H
>valves or yoke y-valves. 

Actually there are Y valves that are 300 bar DIN. Often these are called
the slingshot valve and are/were marketed by OMS and Beuchat. 
These were/are favorites of sump divers and no-mount divers who would push
their tank in front of them in cave systems too tight for side mounts.(I
prefer two compact tanks wrapped in a small BC rather than one large tank
for these type dives).
I have not seen these advertised by OMS since around '95 but they may still
be in production and available.

From a durability and design standpoint the slingshot valves are superior
to the H valve. The slingshot valves have fewer moving parts (fewer O-rings). 
H-valves are high pressure swivels that can actually be unscrewed under
pressure to the point of rapid gas loss (However this would have to be a
deliberate act most likely). Nevertheless the dual barrel O-ring design is
proven and is the best design choice for manifolds from various manufacturers.

If you are set on having the redundancy of two first and second stages
(which I think is wise) for your diving, then I'd say choose the Slingshot
DIN valve over the H valve. Now that is IF you can locate one for sale.

If you imagine you'd ever need doubles then the H-valve can be converted to
a manifold with the purchase of an isolator and a left hand valve.


Regards JD


"SILT HAPPENS"JD   JEFF DISLER
  SAFE CAVING       NSS 26000
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