The method and use of the padding and underlayment device and method disclosed is directed to method and device for supporting the hull of a watercraft using a bunk board with an underlayment pad or cushion attached to the bunk board, the underlayment pad cushion is constructed with an closed cell foam structure that has little to no water absorption and is 2.5 mm to 12 mm thick, the method also includes the option utilizing closed cell foam as bunk board cover over the bunk board padding and underlayment closed cell foam.