From: pyron@skndiv.dseg.ti.com (Dillon Pyron)
Subject: Re: Down Currents (Was Cancun or Coz)
Reply-To: pyron@skndiv.dseg.ti.com
Organization: TI/DSEG VAX Support
Date: Fri, 20 Nov 1992 15:04:19 GMT


In article <1992Nov19.154259.15654@resonex.com>, dan@resonex.com (Dan Kell) writes:
>In article <9211190742.AA26645@deepthought.cs.utexas.edu> RFLNG@CLEMSON.CLEMSON.EDU (Reef Fish      , Large Nassau Grouper) writes:
>>kkwwkk@mixcom.com (TA Shaw)  <1992Nov18.151430.14419@mixcom.com> says
>>
>>> b) I was told that from time to time, the currents that run off the
>>>    wall can be dangerous.  That if the conditions are right, it actually
>>>    can be like flushing a toilet, ie the current is so strong running
>>>    over the and down the wall that it will drag divers down even if
>>>    their BC is inflated?  Anyone else heard of this?
>>
>>IMO this "death grip down current" is one of the popular diving myths,
>>I've done hundreds of dives in Cozumel ... the current can be VERY swift,
>>at times, but I've NEVER experienced the slightest "current running over
>>and down the wall", in Cozumel, or in other swift-current sites.
>>
>>In all reported cases I've heard or read about "strong down current", an
>>analysis could be made that the diver simply lost buoyancy control (usually
>>an inexperienced diver, forgetting to inflate the BC at depth to compensate
>>for wet/dry-suit/BC-compression) to cause the "down draft", and by the time
>>such diver realizes s/he is being "dragged down", no inflation of BC is
>>going to arrest the descent instantaneously -- and so the current gets
>>blamed for the down-dragging, and inexperience/panic distorted the rest of
>>the explanation.
>>
>
>There was a discussion, some months? ago, about this phenomena. It does
>exist. I read an article some time ago in National Geographic about Monterey
>bay that talked about down currents being an erosive force in the Monterey 
>Canyon. Cozumel was mentioned in the discussion quite extensively if I 
>remember right. I seem to remember something about the sand falls down
>there also. What ever.
>
>I tend to disagree that loss of buoyancy control can be blamed for this.
>Even a brand new diver should be able to feel the difference between being
>pushed down by a current and descending due to being negatively bouyant.
>I know the first times I dove anywhere with a current I gained a very
>quick and real appreciation of just how helpless you are in a current.
>Big strong macho divers that we are (you ladies seem to have more sense
>than us males B-) ), we are not fish. I sure can't out swim anything
>we fins, I've tried. Somebody made the comment that if caught in a
>down current to swim towards the wall. I remember the consensus being
>that swimming away from the wall was the quickest way out of the 
>current. (Somebody mentioned swimming toward the wall, this may do
>nothing more than getting you smashed into the wall and pushed deeper.)
>
>If I'm wrong please feel free to correct me. B-))
>
>
>-- 
>Dan Kell                  

In all my dives in CZM, I've never experienced "the killer current".  Doesn't
mean there isn't one.  I really can't believe the Belize story.  Any current
that can suck you down that fast is going to kill you if you're asleep, you're
going down too fast for any rescuer.

My experience at Santa Rosa was that the landform/reef striations are at an
angle.  My buddy and I found ourselves 20 ft deeper than we planned, because
we were following what we thought to be flat lines.  Oooops!

Cosumel is, for most divers, a very different environment.  I learned a lot of
my dive skills there, but for others, it might be tough at first.  And with
some of the grade A bull being bandied around about "killer currents", the mind
gets set.

Down currents in Cozumel, probably.  Killer down currents elsewhere, most
likely.  Killer down currents in Cozumel, not that I've seen.

STOP, BREATHE, THINK, PANIC
>
--
Dillon Pyron                      | The opinions expressed are those of the
TI/DSEG Lewisville VAX Support    | sender unless otherwise stated.
(214)462-3556 (when I'm here)     |
(214)492-4656 (when I'm home)     |"Pacts with the devil are not legally
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PADI DM-54909                     |-Friar Tuck   _Robin Hood:The Hooded Man_

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