At 12:45 AM 5/11/2003 +1000, Jake Anderson wrote:

>I dont know how distinct it would be underwater on the scale you are talking
>about, but generally waves of different frequency travel faster or slower in
>a medium (such as water). Its not generally much but if you could detect it
>you could get a fairly definite distance from the boat.


Actually, knowing the distance from the boat is not the problem.  (It would
be nice, of course, but it would just be a bell/whistle).  The problem is
knowing which direction to go in order to be heading toward the boat.  It
is a lot easier to swim underwater (with dive gear on) than it is to swim
on top of the water, so divers like to get as close to the boat as possible
before surfacing.  (Not to speak of the  danger in surfacing away from the
boat.  There is generally a protective area around the boat for a diver to
surface.  But coming up a good distance away, one has to contend with the
possibility of a fast boat with whirling props coming along, which can
spoil the diving trip something awful. :-)

john

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