I have an 04 PT 175, and the OEM ducer was mounted on the right side (driver side) of the boat. Still there, different ducer tho. I used a "sternsaver" to mount my LSS1 ducer on the step of my boat, its protected for the most part and works good there. No holes drilled in hull as the sternsaver glues onto the boat, and then you mount the ducer to the sternsaver. The sternsaver is similar to the plastic cutting boards available at wally world, etc., but about 3/4" thick. Google it and you'll find it.
GO BIG ORANGE !
I meant to behave, but there were just way too many other options available at the time.