Humminbird wireless fish finder

has any one tired the wireless fish finders like the Humminbird brand? they look like they would be easyer to use on a kayak (no mounting and smaller battery).

I assume you're talking about the cast-able units? I haven't used them, but have read some comments that were quite critical of them. Poor performance issues and issues with longevity (or the lack, thereof.)

  I just bought the Humminbird PiranaMax 215 it is portable and uses a suction cup mount for the transducer.  I would highly recommend this line over the castable humminbird which is really just for shallow shoreline depths.
  You don't even need to spend the extra for the portable if you just use it in one kayak, I move mine back and forth so wanted something easy to transport. Although I think you have to special order the suction mount with the none portable models. I was nervous about the suction cup mount staying on but it stays on my SINK and SOT. No drilling necessary.

Aaron