Just brought out first boat Hurricane sd187 2013 i believe the transponder unit is through hull the depth finder doesn't seem to be working properly stays at 1foot and then may jump to a different depth any ideas please
Change of speed affect the reading? Read ok when stopped?
If the answer to all these questions are no, then you have a failing transducer or....assuming it’s a shoot thru as you stated, it simply could have broken loose from its mounting position inside the hull.