David Strike wrote:

> You have raised an issue that's been bugging me for some while:  That of
> swim-throughs!  When does a swim-through become a cave?

Over the years, I've given this more than a little thought myself and I have
concluded that I don't have a conclusion.  One would think that a swim
through would, at a minimum meet everyone's definition of a cavern which, or
course raises a related question, when does a cavern become a special risk.
I don't have an answer to that one either except that when you see it, you
should be able to recognize it.

> Nevertheless they are still overhead
> environments!  But even the short ones - particularly when narrow and
> obliging folks to swim in single file through them - offer potential
> problems if a person in the middle of a small group throws a 'wobbly'!

Back in the good old middle days, you know, between the "nothing will kill
us" days and the "anything over the head" days that only ended recently,
having something over one's head was not, by itself, a big deal provided
there was plenty of room on all other sides including the bottom, i.e. it
wasn't narrow, and things didn't get narrow between where you were and where
you had to go to get out.  To those who have seen it, the main section of
Blue Grotto in central Florida is a decent example.  It's probably 15 meters
high, wider than it is deep and no more than about 20 meters back under a
cliff.  It's more of a bid dent than a proper cavern.  Not a lot of extra
risk to anyone.  At the back, however, is a swim through that, while it does
not get real tight, is narrow enough and long enough to 1. make lights
welcome equipment, 2. make a silt out a real risk and 3. require a diver to
go one of only two right ways to get out.  This is clearly a significant
risk, certainly a place where no brand new diver belongs, nobody with even a
hint of claustrophobia belongs and probably a place where people who are not
at least qualified to dive in caverns (not necessarily certified, but at
least with comparable experience) belong.  That's pretty much how the rules
for the privately owned site are written . . . and routinely ignored.  A few
of the swim throughs some of us did in Coz went several steps further.
While they were consistently better exposed to natural light, they were also
considerably narrower.  Some would have made a turn around a real challance
even for the smallest of us, yet at least one of our group who proved he did
not belong there, made that dive with us.  I'm not even going to guess how
many more of us had no business there.

Obviously I agree with you on the risk and just as obviously, I have more
questions than answers.  The best I can do is judge for myself and try not
to be part of the problem by going where I know I don't belong or by
encouraging others to go where I can be safe but they can't.

> Nevertheless, swim-throughs never seem to attract the same concern as do
> caves!  Why is that?  :-)

I don't have a good answer, but I have a couple partial ones.  None of them
are good:
1. Commercial operators want to fill their boats.  They sometimes do this by
giving the more experienced, perhaps even overhead qualified, a bit of a
challange and by increasing their income by including anyone that does not
know better than to make the dive.  It's only very recently  that any of the
local operators started asking for more advanced certifications for the more
complex local dives, i.e. those over our normal recreational "limit" of 130
fsw.
2. People don't like to acknowledge their limits, particularly in front of
others who appear to be less limited.  Appear is an important term since, in
my opinion, the most qualified for a dive are almost never the ones
encouraging the less qualified to "take a chance."
3. Some people, maybe most, simply don't recognize the extent of some of the
risks, particularly the silt out risk.  It's hard to comprehend just how
total a silt out can be until you've actually experienced one and, when you
do, you had better have been prepared to deal with it.  There are few second
chances.

The only answer to this problem is for each diver to be responsible enough
to know when to stop.  That may be OK for the Strikes, Bob's, Bjorns, Vivs,
Lees (and anyone else I left out) of this world, but it's clearly not
working for those who have not screwed up enough to know that they can screw
up again that the next screw up may be the last.

Lee