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All this discussion on manifolds reminded me of a trip on the Doria 
where one of the fellows (a very nice gut I might add) spent hours 
tinkering with his gear. One of the contraptions he had spawned was 
pulleys mounted on the manifold valve knobs with ripcords wrapped 
around them in such a manner that one pull of the ripcord and the 
culprit valve would shut. This guy was truely a tech diver. It makes me 
laugh every time I think about it. Maybe the divers who can't reach 
their manifold valves should check into ripcord valves!
 
Then there are the divers who bungee plastic pipe sections over their 
manifold valves to prevent rolling them shut on the roof of a cave or 
wreck. Now they have to call a plumber to remove the pipes in order to 
shut off the valves. There is no substitute for good technique and gear 
configuration.

Next we will see someone configuring a lift bag over their tank valves 
so that in the event of a manifold failure the bag will inflate with 
the escaping bubbles and they will be wisked away to the safety of the 
the surface (this option is not available for cave diving). You could 
even stick your head in the bag and breath on the way up (saying ho! 
ho! ho! as you go). Just kidding?

Aside from the arguments for and against manifolds and independents, 
there are divers using manifolds (by the obvious theorem). So to these 
individuals (myself included) I propose a suggested configuration for 
diving a manifold: Replace at least the rubber valve knob on the left 
side (looking forward) with a brass or stainless knob (both right and 
left if you wish). A metal knob will have less friction with the 
overhead than a rubber knob (ever wonder why your tires are not made of 
metal?) and will tend to resist rolling shut. The knob on the left side 
of the tank tends to roll shut on contact; the right side tends to roll 
open. Leave a rubber knob on the isolator; it doesn't tend to roll (not 
impossible) and the rubber will tend to dampen impacts. Loosen the 
manifold and rotate the isolator a bit forward so it is protected by 
your head. You tend to protect your head. It also makes the isolator 
easier to reach.

Place your primary regulator (the one you are breathing) on the left 
tank valve (the one that tends to roll shut) and your backup regulator 
on the right tank valve (the one that tends to roll open). I would 
rather have the regulator I am breathing cease functioning due to a 
rolled-shut valve than pass off (or take for myself) a backup regulator 
that is not functioning because the valve rolled shut and I did not 
know it. Talk about added stress! The primary regulator on the left 
side will also take up slack in the hose for added streamlining.

Open your isolator no more than two turns and re-check this during 
pre-dive S-drills. Opening it more than that doesn't do much for you; 
you can always open it fully later if you need to. Periodically 
practice gas shutdown drills so you know you can reach your valves, 
like at the end of your decompression in shallow water. Do it with your 
stage bottles on also.

Of course there is no reason (other than poor technique) why you should 
be rolling your valve shut in the first place. You can even check your 
valves during the dive if you wish.

Just my two cents.

Doug Chapman

P.S. Jason, you have already called me an asshole, so come up with 
something more original this time. Can't wait!

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