Ever since I got the PA12, I've wanted to add Side Imaging. The requirement that the transducer be in the water has been holding me back. The easiest solution is the transducer arm like madfrog or ram. Like others have said, I don't want the hassle of pulling kelp/grass/junk off the arm and having something to hang up on around the kayak. I kept scouring the boards for a better solution.
I finally decided to pull the trigger on a 798ci SI with a single sonar/down-imaging/side-imaging compact transducer. Once I was able to see the transducer, I pulled out the Lowrance plate and tried to figure out a way to get the transducer in the water. After much pondering, I decided the only way to get the transducer in the water was to allow the transducer to mount below the plate. I started cutting/grinding away and ended up being able to push the transducer through the plate and directly into the water.
After several trips out to test, I can confirm that you'll want at least 3/4 of the transducer in the water to get decent side imaging results. The more the better.
So far the only negative, it's exposed. With 3/4 of the transducer exposed, it's actually slightly below the hull. Meaning, in the right circumstances the kayak will be resting on the transducer. The outer material of the transducer is not very durable and I'm not sure how sensitive it is to bumping? So far so good, and the data outweighs the risk to me at the moment. Note, on my PA12 the center hull is about a half inch higher up than the outer hulls.
This is how far I've gotten and now I'd like to share this with the PA community and see if we can improve this. It works now, but a retractable/spring loaded/crashproof version would be much better. There has to be an even better way to do this? Hoping to hear some good ideas!
Here is the Humminbird Adapater Kit P# 84505901
798 SI vs 597 DI Transducer
Modified transducer mount