Reserve Air Supply System (RASS) to the Surface
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At NOAA, when doing working dives or in
situations with limited visibility, overhead
environments, or where you can be separated
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from you dive buddy, divers are required to
carry a redundant air supply system.
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At NOAA, we call this a RASS.
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Ideally, all divers on all dives should be self-
sufficient and carry a RASS. You'll be happy you
had one if you ever run out of air.
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The video we are about to see is RASS to the
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So here a diver has run out of air and there's
been a buddy separation,
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so the diver must make it to the surface.
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Here the diver has run out of air...
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Now, here we find a "known". We know the
bottom of the cylinder.
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Once you find the bottom of the cylinder you
can find the rest of the components. So this is a
habit we're starting early on in all divers.
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Later on if you go to do decompression diving
you might be wearing a sling bottle on the side.
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This might be required decompression gas.
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Or you might have a ceiling or overhead stops
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So we start habits here.
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Find the bottom of the cylinder. From the bottom
of the cylinder you can find the second stage.
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From the second stage you can find the on/off
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From the on/off valve you know we are at the
first stage, from the first stage you can find the
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so from one known location you can find all the
components on the pony bottle. So let's watch
all those steps.
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From a known, to the on/off valve, from the
on/off valve, to the second stage,
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put it in your mouth and breathe from it.
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any time a diver
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doesn't have a second stage in their mouth they
need to be blowing a steady stream of bubbles.
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So even in between the second stage and orally
inflating the BC there's still a steady stream of
bubbles coming out of the diver's mouth.
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Here we are adding 2 to 3 breaths to the BC
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and you're catching that air inside your BC. This
is going to make your ascent much easier.
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That air that you've captured inside your BC is
going to expand on your way to the surface.
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Hand positions. Here we have the right hand
with a closed fist above our head. A closed fist
protects your fingers.
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A closed fist also protects your head from
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your left hand holds the BCD inflator/deflator at
the highest point above your left shoulder.
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A couple reasons for doing this: as you're
ascending to the surface the air trapped inside
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is going to expand. You may need to vent some
air from your BC to slow down your ascent.
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also when you get to the surface
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you have to orally inflate your BC, so when you
get to the surface you've already located the
thing you have to blow air into.
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That's the alternate air source inflator or the
second stage located in your left hand.
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Here you see as the diver ascends to the
surface, less and less effort is required. The air
trapped in the BC is starting to take over.
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Still, when the diver gets to the surface go
ahead and take the second stage out and you
take breaths from ambient air
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and you blow that air into your BC.
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Once you are at the surface, go ahead and
ditch the second stage
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taking big breaths from ambient air and pushing
the yellow button directly in front of the
mouthpiece with your two fingers.
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Only blow when you're pushing the button, that
will capture air inside your BC.
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The skill is over when the diver is positively
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