Get a piece of UHMW (cutting board material) about 3/4 inch thick or more and about a foot wide and bolt that to your transom where you want to put your transducer. Use marine silicone to seal up the job. Then you can mount your tranducer, speedometer, next transducer after you break off this one, the real nice one you are going to get after you win the lottery, etc. to the UHMW with SS woodscrews without every putting another hole in your boat. Works slick