Having owned a 18foot I/O searay for about 6 months and ruining two props I was given a transom mount depth finder. Where exactly is the transom? Is the transom part of the I/O or is the transom located directly on the boat. Since I have to drill a few holes to mount the unit I have to know if I will be drilling directly into the bottom of the boat. Also, where is a good place to drill the hole for the cable. I know you pros out there are saying what a dumb a--. But better safe than sorry. Thaks for taking the time to read.