On Mon, 09 Jun 2008 14:55:54 GMT, Short Wave Sportfishing
wrote:

Now, with respect to zero depth performance - pardon my ignorance but
I'm curious why you would be running around in zero depth waters. Do
you have a deep draft sailboat or cruiser of some sort?

Measuring zero depth is relatively easy in a deep draft boat becuase
the transducer typically has more ping delay to work with, assuming it
is not mounted on the bottom of the keel. I find it much more
difficult in something like a dinghy that only draws maybe 10 inches.
I have trouble getting reliable measurements under 3 ft or so.