I own a Outback and not PA....in any case you need to locate the transducer away from the Mirage drive fins to prevent disturbing the sonar signal.
That is why my Humminbird 768 transducer is located just forward of the mast tube.
I found that using Dux Seal, stocked in the electrical dept. of Home Depot works great in mounting the transducer inside the hull....this material is electrical grade, stiff putty....much like clay....and makes for relocating, changing out, removing the transducer painless!
It's also inexpensive....around $2.00 for a 1 pound pug and you need less than 1/2 pound to secure the transducer.