I am just about to mount my transducer into the inside of my kayak, and I am kind of nervous.  I went out and bout what was recommended by a few people on this site (thank you).  It is 3M 5200.  I was reading the instructions for the transducer, and it says that I need to use a 2 part epoxy, and nothing with Silicon.  I am not a chemist, but on the contents list of this adhesive, silica is mentioned a few times.  Should I not use this stuff? 

Thanks guys!

I have read where a lot of people used marine goop to mount transducers in Kayaks.

Goop or Lexel.  Watch out for bubbles.