MyFishFinder.com Just like iceshanty but warmer
I had the same problem with mine. I took some foam and made a float for mine, works better than the arm did.
I love my showdown unit, but I broke the plastic arm my first trip out. It is easy to tip over. I purchased one of the Vexilar floats. When I sent my unit in for the upgrade last year they replaced my arm for free, but I still like using the float better.