Hummingbird Transducer mounting help

I got my new Hummingbird 565 mounted the way I wanted and got the thing lit up but during the test runs in the local pond by my house I can't get the Transducer puck to lay flat enough (I assume) to register anything.  As soon as I place the puck in the water I get a pretty accurate reading.  I have a Ocean Kayak Prowler....I've seen some of you guys with the same set up.  Can you shed some light as to where to mount?  Didn't want to poxy it down til I knew it was a good spot.  Thanks...

I am not sure but I don't think it will work with air between the transducer and the hull. I think it needs to be glued down with no air bubbles or you need to build a cup to hold water to set it in.
Jack

I also have a Humminbird transducer hull mounted in my Prowler 15.  I used Goop to glue it to a flat spot just to the side of the front scupper hole post.  There's very slight angle but there's no significant on depth readings.  I mounted it to the side to allow me to stow rods and things without them getting hung up on the tranducer cable.

mounted mine just astern the cockpit (useless) mini-hatch.  I wouldn't use epoxy, even tho the instrudctions say to. I think they are thinking all boats are fiberglass.  Use marine or plumber's Goop (brand name).  It can be removed after set by first warming it with a hair dryer, but that also means you can't let the bottom of the hull get too warm as in transporting upside down in intense sun. Mount it where you can get at it to remove and reattach, because you will eventually.