On Sat, 10 Jan 2009 13:19:47 -0500, Marty wrote:

Edgar wrote:
The earlier comment about the depth sounder is interesting because ISTR that
I read somewhere that a transducer working through the hull does leave a
clear spot.

Well, I'm like Bruce, I have a depth sounder with the transducer in a
well epoxied to the inside of the hull; I have never seen a "clear" spot
on the outside of the hull where the transducer is mounted.

Cheers
Martin

Perhaps, although I'm not really sure about it, the "stuff" is
frequency sensitive?
Cheers,

Bruce
(bruceinbangkokatgmaildotcom)