Transducer mounting

Do you fill that tube with water?  Or is there goop on the bottom inside of the tube?

There's Lexel inside the tube. It takes a couple days to cure, but when it does, it's in there for good. It gives a very accurate sonar reading and temp as well.

Just an update in case anyone was curious....

As Z suggested, the hull was fine and air was the problem...

I showed my setup to Bsteve's last week when we were bass fishing on the Willy, he pointed out the fact the closed cell foam I was using had air in it.  I had missed the part about making sure there was no bottom to the "tray/puck".  I cut out the bottom of the foam, then gooped it down, took it out last night to try it out... 

 Awww ya...