I have been given a LOWRANCE X55a. It's used but cost me nothing at least not yet. I have all the cables but no paperwork. It has the type of transducer that attaches to the transom via a suction cup. Here is my question. Is there a certain type of transducer, other than the one that I have that can be mounted to the inside of the hull without cutting any holes or can I use the one that I have? I have read about the baggie filled with water to test for the best location of the transducer and this method would work for me to test the transducer but the boat is out of the water and I would like to complete this job before the new sailing season. 