"Phil Abuster" wrote in message
...
Silicon attenuates too much (
http://scitation.aip.org/getabs/serv...cvips&gifs=yes )
, epoxy is much better. Mineral oil is very good, but it can be
messy/complicated. Ideally you want to match the speed of sound in the
materials to water to avoid high power reflections at the
transducer-epoxy-hull-water interfaces.

To bleed air bubbles from the epoxy, take an orbital sander put on a felt
pad and place it on the other side of the hull opposite the epoxy. The
vibration will bleed out the bubbles, do this before applying the
transducer and the epoxy must still be unhardened. Epoxy does sheer off in
one nice big chunk when removing. Also be sure to fill in the air bubbles
in the fiberglass mat of the hull if there are any.

Make sure you get a license before doing this!


Huh? How do you do that with the boat in the water... without electrocuting
yourself or the nearby diver? And, how do you do it after the epoxy has
hardened?

License??

--
"j" ganz @@
www.sailnow.com