One thing you might think of trying is an air pillow for an aboveground pool winter cover. They come in 4'X4' and 4'X8'. Reasonably priced too. Blow them up and put under your cover. Take a look at them here.
I know Doc got rid of his because of lack of use. But he has the party barge along with the go fast boat. SO little time left it.
My wife won't step foot in a go fast boat anymore. My brother ruined her with his idiotic attitude. She did enjoy the ride on the houseboat though. I don't think...