----- Original Message -----
Sent: Friday, October 28, 2005 2:30
AM
Subject: Re: [PSUBS-MAILIST] Another
nutcase here.
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.
----- Original Message -----
Sent: Friday, October 28, 2005 2:18
AM
Subject: Re: [PSUBS-MAILIST] Another
nutcase here.
Bill,
Thanks for that. So
basically, you get the weight you need via the keel. That makes
sense. Also safer too by having the keel jettisonable, up she pops
like a cork, as long as you're not too deep and "bend" yourself I
guess.
I have been following the hull
test threads very carefully.
I don't like the idea of being
exposed to the depth pressures, even if it's not very deep. I seem to
be particularly sensitive towards that. I can't dive / swim very deep
without my head wanting to explode (implode I suppose).
Still
thinking.....pondering....planning.
Myles.
----- Original Message -----
Sent: Thursday, October 27, 2005 4:50
PM
Subject: Re: [PSUBS-MAILIST] Another
nutcase here.
Hi Myles.
In overcoming the buoyancy of the hull
you might make an ambient heavy by filling its keel with lead,
bricks, concrete, maybe even sand, anything heavy for
ballast.
I've seen pictures where fellows who were
taking their sub out for its first test took a bunch of bricks along
and if they weren't heavy enough, just started loading bricks
into the sub's
bottom until they were heavy enough.
To use the same weight as you said to make a
pressure hull, you have to build interior hull reinforcement rings, have a
thicker pressure hull and also worry about the
roundness of the pressure hull and how much
pressure it will take. You have to worry about leaks and hull penetration
fittings leaking. You have to do an unmanned
pressure test like we have been recently and
presently been discussing in the group's postings.
The ambient design does away with all that by
simply keeping the water out with air pressure. Theoretically the
ambient hull outer walls could be as
thin as a beer can since the pressure inside
will be the same as the pressure outside. Of course you wouldn't want to
make one that thin because it wouldn't be practical,
but it would be possible to do so. There are
fellows here who build pressure hulls all the time, but it is much
harder to build a pressure hull than an
ambient one. Although
there have been wooden, fiberglass and
epoxy pressure hulls made for 1 atm subs that didn't go very
deep, they still are much harder to
build than a ambient hull.
The main advantage of the ambient hull for
scuba depths diving is that you can make it out of practicall any material
and you can make it in almost any shape you want
and do not have to make it spherical as most
pressure hulls are to maximize resistance against extreme external water
pressure. The main detraction of an ambient design is that
your body will be under the same
pressures as a scuba diver at whatever depth you dive to and have to
adhere to dive tables just like a diver does so you don't get the bends.
Also
as you submerge and increase the air pressure
inside your sub to equalize the outside water pressure and keep it out,
you have to pinch you nose and blow to equalize your sinus
cavities just like a diver does as he
decends. Also you cannot exceed safe scuba diving depths so you cannot go
nearly as deep as a 1 atm sub can go. But for shallow sub
diving
not to exceed a maximun of 130 ft, an ambient
design would be much cheaper and easier to build than a 1 atm
sub.
Bill.
----- Original Message -----
Sent: Thursday, October 27, 2005
4:18 PM
Subject: Re: [PSUBS-MAILIST]
Another nutcase here.
Rick,
Love it !!
I was giving thought to an
ambient, since my dive depths aren't going to be very deep, but, I don't
really understand how you can make them heavy enough to sink. If
you can, why not just use that weight to make a pressure hull instead
? It's not totally clear to me. I can get access to good
quality pipe and weld so, I just thought it would be best to go 1
ATM. (By the way, plywood here isn't cheap.). Your concept
of keeping the costs down has a ton of merrit though.
Myles.