Thanks for the great information. Just got back from boating on Lake Ontario. The transducer in hull seems to be working well. I am getting good depth readings , just don't know how well the fish finder is working , did not see any fish but it was picking up the bottom and the water seemed mostly clear above the bottom. I guess it is time to learn how to use the fish finder. Prior to the outing, I did disconnect the nearby Sea Doo stock transducer so as to not get interference. The next time I will see if the transducers can work side by side, I believe they both use 200 hz, so not so confident about that.