I live in key largo and put my pontoon in water for the summer months, store in winter. This is 3rd summer in saltwater. I painted with antifoul paint when purchased and had to repaint beginning 2020 summer. When I pulled pontoon out a couple weeks ago I found that there is white rust at waterline and a couple of patches where paint fell off because rust underneath paint. Please see pictures. I would like to know what I need to do before I put her back next summer and what I neglected to do to prevent this. Thank you