I have a small well molded into the bottom near the mast on the starboard side that looks like it was for a transducer like now or never installed. There is a cover for it suggesting it might have held water or some other media for the transducer. My transducer was under the aft settee locker on the starboard side. It was external transducer but someone had made a little boat shaped box and attached it on the hull. It looked kind of silly and was obviously a drag. I got rid of it and now the transducer is in that same place (aft starboard settee locker near center line) but flush with the hull. I had the shop do it, not comfortable making or fixing holes in the hull. If you can get the internal transducer it would be an easy install.
Geoff