I did somehting a few years back with a back of boat transducer I attached it to a piece of 3/4 starboard about 30 inchs by about 3 inchs wide as I HATE drilling holes in my boat put it on the "stick" then 2 screws above the water line with sika on screws. and the cable holders all the way done the stick and then you can rellay fiddle with transducer to get it perfect.. I got the starboard at a place that sold it, if I remember it was like 10 buck out of the scrap bin,
Hope that helps
Good luck wolf