Shortly after taking possession of my PA, I sold my Humminbird 385ci. That same day I found a great deal on a Humminbird 898c SI on Kijiji Toronto. Yes, it's overkill I'll admit it, but the deal was too good to pass up as I really wanted to use side imaging this year.
I decided to use RAM Mounts for both the display and the transducer arm as they have a little give if you accidentally hit them. I used a 1" ball with a 6" extension for the arm, and a 1 1/2 ball mount for the display. By using something that is adjustable I'm able to lower the transducer below the hull to avoid interference from the fins.
As the transducer needed to be mounted externally, I chose to mount it beside me in case I need to clean it from weeds, or move it when going into the shallows. I made the arm from 2" aluminum flatbar. After cutting the end and bending it to mount the transducer to, I coated both ends in Plastidip.
To keep the transducer cable under control and to keep it from vibrating, I heatshrunk it to the bar.
As for the GPS puck, after consulting with Humminbird, they agreed that mounting inside a plastic hull should still allow it to function. After coring out some closed cell foam, it gets pressure mounted above the rod holders.
The final product...