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Hi Myles.
If you build an ambient design there is simply
nothing to do but deal with the air pressure. Otherwise you need a 1 atm design
if your head hurts under pressure.
When your head hurt diving/swimming, did you know
to pinch your nose shut and gently blow to equalize the pressure in your head
cavities?
When your body is under pressure from either the
outside water or the interior air it absorbs more nitrogen which stays in a
liquid form as long as you
stay under that pressure. Your body can safely
absorb a certain amount of nitrogen and be ok, but too much nitrogen
(saturation) can make you feel high and is disorenting
and can cause you to make mistakes like you were
drunk and even make you pass out and drown if diving. That comes from staying
down too long and not watching
your diving tables. With dive tables you know how
long you can stay down pressurized at a given depth. Then your body has an X
amount of nitrogen absorbed into
it staying in fluid form in your bloodstream and
tissues. If you surface too quickly after staying too long the nitrogen bubbles
up from a descrease of pressure like a shaken
up soda and they
bubble and expand in your blood and tissues and can cause slight discomfort,
organ damage, even death. It is all dependant on how long you were down
and at what depth and how fast you came up.
If you follow your NO DECOMPRESSION diving tables
and do not exceed your time for a safe scuba depth and then always do a 3 minute
hang at 15 ft and then surface, you will be fine.
There are some who might say a jettisonable keel
would be good in a 1 atm sub, but I don't think you will need it in an
ambient for two reasons....
1. If you jettisoned your keel in an ambient
sub I assume it would be an emergency and you probably have been down a
while trying to figure out how to surface a broken sub.
In that case you may have
exceeded your dive tables depth and or time which means you may have some or a
lot of nitrogen saturation. If you have done this you are now
in a situation where you need to
slowly offgas the nitrogen and the best thing to do is have oxygen bottles on
board to help decrease more nitrogen getting into your system.
Then you need to know
saturation diving tables and get the sub up to a certain depth and keep it there
for X amount of time. Depending on how deep you are and how long
you
were down, you may have to
stop at several levels on the way up to
decompress. Otherwise you will get the bends and have to be flown to a
decompression chamber for treatmeant
for decompression sickness if
you survive. So rocketing an ambient sub that's hull along with your body is
under pressure to the surface with the sudden decrease in
pressure and resultant bends and
decompression sickness can kill you or give you health problems for the rest of
your life. One of my dive club members recently came up from
230 feet in a tech dive in a
cave in a sinkhole close to here. Her isolation valve was closed on her doubles
rig and she was breathing pure helium instead of with an oxygen
mix.
At 50 ft she was unconcious, at
30 ft she stopped breathing. Her dive partner got her up. She died three times
and they brought her back. Had to drive her from the sink hole to
a spot where the chopper could
pick her up to med evac to the hospital. She is still in the critical ward with
damaged heart, liver and other injuries with some possible brain
damage.
Her situation was not one of the
bends but breathing the wrong mix, but it underscores the seriousness of what
depth time and pressure can cause.
I don't want to scare you but
this is nothing to shrug off lightly. Do not rocket to the surface in an ambient
after being down a while. You could do it if you were very shallow and had
only
been down a few minutes,
but I still would not advise that even. It wouldn't matter in a 1 atm sub
because the pressure is the same as topside so you COULD rocket a 1 atm without
ill effects.
2. You do not need to have a jettisonable keel in
an ambient by its very design. The ambient will have an opening in the
floor or a trapdoor that you can simply jump right out into the
water
and since you are already at
that same water pressure you can simply bail from the sub using a bail out tank
and facemask and if you did not exceed your dive tables just do a three minute
hang at
15 feet (carry a depth gauge)
and you will be fine. Carry a inflatable raft, buoy and line. When you bail out
take the raft with you and release the buoy that is attached to the sub so it
floats to the surface and
marks the sub's spot for
retrieval. If you DID exceed your dive tables, carry them in the sub with you
and if you have the chance before you bail, look and see what your
decomppression stage
levels and times should be
and then do your decompression hangs as best you can. Even a few minutes hanging
and decompressing can make a big difference between no ill effects, slight ill
effects....and
death. So you see, there is no need for a
jettisonable keel in an ambient design in the first place. You just lift the
trapdoor (if there even is one) and bail out.
I didn't mean to scare you off of building an
ambient my friend, I just wanted you to know the risks. If you do this, you need
to definately become a certified diver. That will give you skill and an
understanding
necessary for operating an ambient. It is as
safe as you make it and operate it. Dive tables, dive tables, dive tables.
Did I mention dive tables?
Hope this helped you.
Bill.
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