fish / depth finder suggestions

[chumbucket]

You probably need to move it down towards the keel more to keep it in "cleaner" water (ie; less turbulance). I've had several Humminbird products over the years and was never satisfied with any of them.
I would recommend a Garmin, Furuno, or Raymarine (Raytheon), and possibly a Simrad. At the very least, see if you can get an Airmar transducer that works with that unit.

Squash that Airmar idea (at least I think so). Looks like they make them for just about everyone but Humminbird. Might be best to contact their tech support staff and ask the question anyways. Airmar are very reliable transducers.

http://www.airmar.com/marine/enduser/enduser_index.html