Not sure if this helps. I am looking at these for potential goose nests. Drive four metal posts (6-8' long) at each corner into the bottom of the pond. Bolt the feeder down.
Platform will move up and down on the posts with the water level changes. There are lots of manufactures. I just copied the pic from the Home Depot web site. The 2x4x1 is rated to 450lbs and I couldn't find the float rating for the 4x4x1. The cost was listed at $170
