lowrance help

my new tracker has a x47 on it and has been great,but yesterday we had been fishing 3 or 4 hours my partner told me the depth finder was acting crazy,the screen was very arractic,sometimes with lines,sometimes the depth would flash 60 feet(thats what it does when not in water},and sometimes it would clear up but show fish on it very tiny.i have check all the wires,connections,the transducer is clicking,and i have reset all defaults,still does the same.any ideas????