Goop is easiest, I use the same FF/GPS in boat, and kayak, and get similar readings. (boat puck is transom mount in water)
I just scraped my puck off my kayak last night to install in a different kayak. It looks like this, and I still got accurate water temps, depth, bait balls, and unmistakable YT arcs. FWIW, this puck had been in my kayak 9 months.
