On Thu, 19 Apr 2001 16:27:44 +1000, David Strike <[log in to unmask]>
wrote:

>On Thursday, April 19, 2001 9:22 AM, Lee Bell wrote:
>
>(snip)
>
>> IF YOU'RE NOT QUALIFIED TO BE IN A CAVE STAY THE HELL OUT OF THEM.


>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?

    When you CANNOT SEE the light at some CLOSE exit to surface.

An excellent topic for thoughts!


>In many instances the difference is a difficult to determine nicety!

Indeed.  Because it is DIVER-dependent.  Will elaborate below.


>And it's something that few divers give thought to.

That's no different from the fact that few divers give sufficient
thought to any other form of diving.  :-)

That's the beauty of being a "self-reliant" diver and practice the
rule of "know YOUR limit ...".  From that point of view, whether
one SHOULD attempt, is experienced enough to attempt, any particular
swim-through is NO DIFFERENT from a diver's judgment on doing any
OPEN WATER (with no overhead) dive.  The ability for one to "head
for the surface" in the event of a catastrophic equipment failure
is perhaps the "pragmatic" difference between diving a cave and a
swim-through, leaving out the silt-out situations in caves not
found in any swim-throughs.


>For many people - at whatever level of experience - swim-throughs
>are an attraction that they're encouraged to experience.

Here, I am not sure who encourages whom.  In Cozumel, it seems more
likely that some "unqualified" divers wants to do the "devil's
throat" dive and a dive shop discourages it, than the opposite.  It's
more of a case that many divers dive BEYOND their own limits, in
depth, and in the ability to be self-reliant under certain more
challenging environments -- be it depth or swim-throughs, and especially
in the swim-throughs in Punta Sur, often indiscriminantly called
"devil's throat" in the hundreds of swiss-cheese holes for EASY
exit, at any time during a rather lengthy swim-through.

>Some of them can be lengthy affairs; others are little more
>than a few metres in length.  Nevertheless they are still overhead
>environments!

Aha!  So what's such a big deal about an "overhead environment" if
the "overhead" part is always escapable within a few kicks to the
"open" part?  For that matter, the "glass ceiling" (term used for
obligated deco) in a dive with "no overhead" is certainly as
dangerous, if not more so, than a swim-through where the LIGHT
and SURFACE are always within easy reach (for the diver who attempts
it).


>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'!

Then the person in the middle shouldn't be there in the first place,
if said person can throw a 'wobbly' whatever that is <G> or
incapable of being self-reliant and head for the EXIT or get help
from the nearest SOB.   In that respect, such a swim-through is
much safer because a BUDDY or SOB is always CLOSE BY, whereas in
open-water with strong current or bad vis that may not be always
the case.  In ALL cases, the true test is for the individual
diver to ANTICIPATE the worst-case scenario and be able to
determine how s/he can successfully handle it should it happen.

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

Many reasons.  Perhaps the simplest one is, in swim-throughs, you can

        always SEE the light at some CLOSE exit to surface.

-- Bob.