I have my fishinder bungee chorded to the front hatch. I can reach the controls fine, but I am 6'4" and my arms are long for my height. I like it centered and down low like that so it is out of my way. I also have a pretty big screen which helps.
You can see my setup in this picture:
I shoot through the hull with the transducer and I run the battery and transducer cables in through the front hatch and then close the hatch with the same bungee that holds the fishfinder in place. No drilling for my setup.
Another thing I have seen folks do is use a ram mount in the sailing mast hole. If you add an extension arm you could move the finder around as you wished during the course of the day.
Fish tremble when they hear my name
A ship in harbor is safe -- but that is not what ships are built for.
--John A. Shedd, Salt from My Attic, 1928