dbohar,
I considered taking a course but haven't gotten around to it. Your
buoyancy control has to be perfect. Just couldn't see what would be that
interesting in a cave. Plus you have to reconfigure to a long hose. I
might give rebreathers a go at some point but for now open circuit is fine.
Paul


wrote:
Cave diving is one of the few things I will not try. It is one of the
few sports where almost ANY mistake is fatal. I am glad some people do
it but I consider it to be an elaborate form of suicide.

One of my friends died due to a faulty Buoyancy compensator. He was
250' down in Little Dismal Sink and had managed to connect
Little_dismal to Emerald forming the worlds longest mapped underwater
cave. They were breathing some weird mix of air. To exit the cave,
they must take off their tanks and push them through a constriction
while still breathing through the hose attached. Suddenly, There was a
cloud of silt and when it cleared they saw his light waaaaaaay above
them. They were in a dome that rose over 100' with the constriction at
the bottom. They slowly made their way up to him, pausing for the
decrease in pressure. He was alive and still breathing and was looking
around they say. However, they could not get him to go through the
constriction. They even tried tying his hose to him and somehow
pulling the tank through but nothing worked. They kept trying till
they were nearly out of air and had to leave him. When they got back
down with more air, he was dead of course. An autopsy later showed
that the rapid ascent had given him a brain embolism so he was sort of
brain dead when they were trying to get him through the constriction.
I probably have some of these details wrong because I am not a diver
but it was basically a bad BC. These guys were operating on the edge
of dive technology. A good friend and good caver lost.
Later, some of these same people pioneered the use of rebreathers for
this same cave system and they were later used in Wakulla and in
Mexico.
I think the obsession of cave diving is the same for any part of the
unknown. Finding some place no other human has ever seen gives you
chills and makes you feel closer to the almighty than anything I can
think of. Until a century ago, it was still possible to do this on
earths surface so exploration by sail drove the great age of
exploration. Today, there are very few unexplored places left on
earths surface so people who are obsessed with exploration have to some
extremes, like caves or the ocean depths or even space.
Dont get me started or I'll rant all day about this.

dbohara,
The weird air mix is Tri-mix. The air we breath is 21% oxygen and 79%
nitrogen with a few trace elements. What these guys were doing is tech
diving, what I do is recreational diving. We're limited to 130'. After
150' or so it's a good idea to go with Tri-mix. Tri-mix is a blend of
oxygen, helium and nitrogen. The oxygen is lowered to something like 16%
and part of the nitrogen is replaced with helium, can't remember the
percentages. After 130' the chances for nitrogen narcosis go up as the
depth increases. So less nitrogen is beneficial. After about 160' or so
oxygen starts to become toxic, hence the less oxygen content. So the
tech diver carries along a third air cylinder with normal air to get
down to the depth where he'll switch to his tri-mix gas to descend
further. On the way up, he might take up to two hours to stop at various
depths to decompress. He better not forget to change to the normal air
tank as he comes up. He has to plan to have enough gas to fulfill his
decompression obligation. Failing to do this or coming up too quick can
get him bent or death. I've read a bit about it, but no thanks it's not
my cup of tea. :-)
Paul


wrote:
One of my friends died due to a faulty Buoyancy compensator. He was
250' down in Little Dismal Sink and had managed to connect
Little_dismal to Emerald forming the worlds longest mapped underwater
cave. They were breathing some weird mix of air. To exit the cave,
they must take off their tanks and push them through a constriction
while still breathing through the hose attached. Suddenly, There was a
cloud of silt and when it cleared they saw his light waaaaaaay above
them. They were in a dome that rose over 100' with the constriction at
the bottom. They slowly made their way up to him, pausing for the
decrease in pressure. He was alive and still breathing and was looking
around they say. However, they could not get him to go through the
constriction. They even tried tying his hose to him and somehow
pulling the tank through but nothing worked. They kept trying till
they were nearly out of air and had to leave him. When they got back
down with more air, he was dead of course. An autopsy later showed
that the rapid ascent had given him a brain embolism so he was sort of
brain dead when they were trying to get him through the constriction.
I probably have some of these details wrong because I am not a diver
but it was basically a bad BC. These guys were operating on the edge
of dive technology. A good friend and good caver lost.
Later, some of these same people pioneered the use of rebreathers for
this same cave system and they were later used in Wakulla and in
Mexico.
I think the obsession of cave diving is the same for any part of the
unknown. Finding some place no other human has ever seen gives you
chills and makes you feel closer to the almighty than anything I can
think of. Until a century ago, it was still possible to do this on
earths surface so exploration by sail drove the great age of
exploration. Today, there are very few unexplored places left on
earths surface so people who are obsessed with exploration have to some
extremes, like caves or the ocean depths or even space.
Dont get me started or I'll rant all day about this.

Remarkable story, dbohara. Do you think your friend regretted his decision
spend his life diving?



Padeen

If possible, I would think he would be happy he spent so much time
diving. He got got into dry caving because of a messy divorce and he
wanted to get his mind off of it. When he learned about cave mapping,
he returned to his former interest in scuba and applied this mapping
skill to cave diving. When he made the first good map of spring called
McBride Slough, it was a first in underwater cave mapping in being so
accurate and detailed and got a lot of attention.
Although his death was nearly 20 years ago, I can still see his
enthusiasm and the far-away look in his eyes as he described swimming
through vast hallways with drowned columnar formations stretching off
into the distance out of reach of his light(You have to realize that
these caves where formed when the water level was a couple hundred feet
lower, the Gulf of Mexico shoreline was 50 miles furhter out 10,000 yrs
ago). Being a dry caver, I could picture this but with the added
experience of floating through it instead of climbing through it.
The exploration-discovery obsession really had hold of him and I can
see why. It is a nearly religious experience that makes people take
risks that may seem extreme but it is not for macho reasons.

Padeen wrote:
Remarkable story, dbohara. Do you think your friend regretted his
decision
spend his life diving?



Padeen

I can understand that far-away look. I've often pushed my boundaries for
what I consider something worth dying for, and have lived with the premise
that any death doing something I love, active and engaged, would be
worthwhile, compared to dying in an auto accident, or a cancer ward.
Thanks for your description of your friend's passion.
Padeen


wrote in message
oups.com...
If possible, I would think he would be happy he spent so much time
diving. He got got into dry caving because of a messy divorce and he
wanted to get his mind off of it. When he learned about cave mapping,
he returned to his former interest in scuba and applied this mapping
skill to cave diving. When he made the first good map of spring called
McBride Slough, it was a first in underwater cave mapping in being so
accurate and detailed and got a lot of attention.
Although his death was nearly 20 years ago, I can still see his
enthusiasm and the far-away look in his eyes as he described swimming
through vast hallways with drowned columnar formations stretching off
into the distance out of reach of his light(You have to realize that
these caves where formed when the water level was a couple hundred feet
lower, the Gulf of Mexico shoreline was 50 miles furhter out 10,000 yrs
ago). Being a dry caver, I could picture this but with the added
experience of floating through it instead of climbing through it.
The exploration-discovery obsession really had hold of him and I can
see why. It is a nearly religious experience that makes people take
risks that may seem extreme but it is not for macho reasons.

Padeen wrote:
Remarkable story, dbohara. Do you think your friend regretted his
decision
spend his life diving?



Padeen