Chris B. McKinney wrote:

> I would be interested in hearing what else I might have taken
> into consideration if I had more experience or if I'd been cave
> trained.  As it was, all I considered was the bottom composition,
> the likelihood of getting stuck, what I would do if I did get
> stuck, and how easy it would have been to get to the surface
> without air.  I did not (at the time) consider that it was
> towards the end of a dive.

I've switched the order of your post to address specific issues.  First, by
my own standard, I can't tell you whether you were qualified or not.  The
fact that you survived suggests you may have been qualified for this swim
through but only you can say for sure.  To answer your question on what you
might have considered here are a few possible issues.  While these look like
questions, they're not.  They're food for your thought.
1. If you were certain that you could avoid getting stuck, including getting
equipment hooked on something sufficient to require assistance, you had a
good start.  Did you think about entanglement?  If so, you had a better
start.
2. You suggest that you were comfortable that there was no risk of siltout
because there was a gravel bottom.  A gravel bottom, by itself is no
guarantee against a silt out from the bottom, but accepting that the bottom
was not a silt risk, the question becomes did you also check out the top and
sides?  The bottom is not the only place silt collects.  Siltouts can and
have been triggered by a diver's bubbles alone.
3. Another thing you may not have considered is what would happen if you had
an equipment failure, i.e. suddenly had no gas to breathe.  If you were
passing single file and assuming you did not have room to turn around in the
passage, did you consider how you would signal someone behind you that you
had no gas usable gas supply?  Did you consider how you would signal someone
in front of you, facing away of the same thing?  It's pretty obvious that
the standard out of air signal won't work for someone facing away or someone
behind you, but an alternate plan is not something everyone automatically
considers.
4. The final thing I can come up with is, if you considered the possibility
that you might have a need to share air, did you consider whether sharing
air would be possible everywhere in the passage?  Most cave divers use at
least one significantly longer than standard regulator hose for just this
reason.  There are alternatives to the long hose, but the narrower and
longer the passage, the less likely they are to be effective.

Note that I'm not saying you failed to consider any of these.  These are
things you should have considered at least briefly before entering any swim
through.  This is not to say that every swim through will involve these
risks or, for that matter, any of them.  It's simply to say that these are
the kinds of risks that should be considered, consciously or otherwise, that
an unqualified diver might not be prepared for.

> In one of my first dives after receiving OW certification, the DM
> announed there was a swim-through at the site and asked if we'd
> like to swim through it.  This was my first time to hear the
> term; I said that I had been taught to stay out of any overhead
> environment.  The DM told me (1) This didn't count; but (2) I
> wouldn't have to swim through if I chose not to, and (3) I could
> make my decision after seeing it.

This is an excellent example of why you have to be the one responsible for
determining whether or not you are qualified.  The DM knew your
certification and knew you were not certified for the dive, i.e. that you
had not met the qualifications, the standards included in Strike's
definition of qualification.  His agency would not have agreed with his
decision.  He was, in fact, willing to take you on a dive that, by the
standards of his certifying agency, he should not have taken you to in the
first place.  Even though he did indicate you could chose after seeing the
swimthrough, he compounded his error, at least by his agency's standards,
when he told you "this didn't count."

> If worst came to worst,
> we were only about 10 m. deep at that point, IIRC, and I felt I
> could easily reach the surface w/o air.  The bottom, BTW, was
> gravelly, w/ no worries of silt.

Very recently, there was a body removed from a cave.  It was an experienced
caver who tried to negotiate a narrow underwater passage between two
chambers, both of which were dry.  I'm not sure whether he was a certified
cave or cavern diver.  He got caught partway through a short, shallow
passage that others had succesfully navigated in the past.  He could not
extricate himself and could not be extricated or supplied with gas by those
behind him.  As I recall, he was much less than 10 meters deep.  Despite
efforts to help him and to get additional help, he died in that cave.  One
can only assume that it was a very unpleasant way to go.  It took highly
qualified cave rescue personnel a couple of days just to recover his body.
He died because a risk he didn't prepare for (or avoid if he couldn't
prepare for it) reached out and took his life.  Shallow depth is absolutely
no guarantee of safety.

Please take this in the spirit in which it is offered.  The more things you
know to think about, the better job you can do in planning to dive safely,
in staying within what you are qualified to do.  This is not a bad thing for
any of us.  Even knowing that I've been diving for almost 40 years, that I'm
certified as Master Diver by an agency Strike represents (or represented)
and knowing that I have cave diving experience (in the days before training
for cave diving was available), he responded to my statement that I thought
I might take a cavern and cave course with a warning to be careful,
basically, to be sure to DIR (do it right).  While I suspect there was more
than a little tongue in cheek involved in Strike's DIR reference (they're
very good cave divers who appear to think they know everything there is to
know), his warning is a good one.  You can imagine how much better I think
it is for someone who lacks my diving background, or his, or Bob's.

Lee