I have since raised the transducer a little and it is now reading the
bottom while on plane. Apparently the dealer mounted it a bit to far
below the hull... which some folks (on another board) mentioned will
cause bubbles.

I had a chance to compare this unit head to head against a Humminbird
565 (hi-res) finder... and the Humminbird painted a much nicer picture
of the bottom... After that comparison, I feel that this navman is
really only beneficial for montioring structure on the bottom and
seeing balls of baitfish.... where the Humminbird will actually see the
game fish clearly.