"Capt. JG" wrote in message
...
"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




You wouldn't install a thru hull with the boat in the water would you?

The most interesting use I've found for the display type depth finder is to
press it against your belly or head and use it as an ultrasound scanner.
It's really neat to see body parts moving (such as your heart, lungs) or
check bladder fullness with it. Much cheaper than a doctor!

The license is so you don't electrocute yourself.

Salty has the whole process down pat. He must have a license.