I don't think you will have any problems with the rivets. Like shortdraw said a transducer board with 3m adhesive will help you be able to find the sweet spot and not have to drill a bunch of holes in your hull. What I am looking at is the distance from motor and transom going to be enough to not interfere with the side imaging. You will not need the speed meter as you will have speed now on your sonar. I am thinking you may have to build you a jack plate to get more distance between motor and transom for transducer. Good that you work with aluminum as you can make one of these if needed.

Jackplate Plans, Construction Notes




Transducer mounting board