Fiberglass boat flooring replacement is a common procedure that a lot of boat aficionados perform to restore their boats and keep them in good shape.after years of use, flooring can get damaged, particularly if left exposed to all weather conditions for a long time. therefore, it will need replacing.. The methods used to make minor repairs to wood and fiberglass floors in a boat are similar in many ways. major repairs or repairs to aluminum . of the boat floor. pull back the carpet.. This restoration tutorial video shows how to replace your rotten marine plywood floor or deck, including cables, fuel tank, fiberglass and carpet more to follow...