Method of making marine decking

A method of manufacturing non-slip marine decking for a marine dock that is to have a surface cleat to facilitate docking, the method comprising the steps of:

• heating a stack of sandwich material including first and second reinforced thermoplastic skins, first and second thermoplastic adhesive sheets, and a cellular core positioned between the skins and between the sheets, the cellular core having a plurality of hollow cells that share boundary walls, wherein the hollow cells are co-extensive with a space between the thermoplastic adhesive sheets and each of the hollow cells has an axis oriented transversely to the skins and a cross-sectional cleated shape in a plane orthogonal to the axis, the skins and the thermoplastic adhesive sheets being heated to a softening temperature;
• providing a compression mold including upper and lower dies, which when closed, define a mold cavity;
• placing the stack on the lower die in an open position of the mold;
• moving the dies toward each other until the mold is in a closed position;
• allowing the heated stack to cool in the mold cavity in the closed position until inner surfaces of the skins are bonded by the thermoplastic adhesive sheets to top and bottom surfaces of the cellular core to seal the hollow cells;
• and
• applying pressurized gas at an outer surface of the first skin of the stack in the mold cavity to form in the outer surface of the first skin, in order to enhance surface traction of the outer surface of the first skin, a plurality of cleat-shaped debossments having a cross-sectional cleated shape in a plane orthogonal to the axis which matches the cross-sectional cleated shape of the hollow cells, wherein a first upper outer surface portion of the first skin is disposed below a second upper outer surface portion of the first skin where the first skin is bonded to the cellular core after cooling to form in the outer surface of the first skin the plurality of cleat-shaped debossments which each extend across one of the plurality of hollow cells to which the first skin is bonded.