Mounting a Transducer

Any kit's to mounting the transducer to the haul of a kayak? or is it just a DIY thing.
Has any one try just hanging it over the side with a pvc in a J shape to remove when not in use . I notice that at Bass Pro Shop had a simple set up on a Uncle Bucks Pond Prowler 10ft Boat , it was clamp on to one of the transoms.

http://kayakfishinggear.com/search.aspx?find=transducer+mount

As another option is to mount inside the hull using electrician's putty.

2 minute job.

That's how a lot of guys do it, but if water temps are important to you your transducer needs to be in the water.