Abstract: A plastics structure, such as the center-board for a sailing boat or a vehicle body panel, comprises a foamed plastics material containing arrays of high tensile steel reinforcing wires having a diameter in the range 0.040 to 0.125 inches and a yield strength of not less than 200,000 psi, located in the surface layers thereof at a distance of not less than 0.06 inches below the surface, to yield a structure having improved impact resistance and enhanced rigidity. The wires may be preformed plastic spacer elements or on a plastic sheet material which then forms the outer surface skin of the structure. Polyurethane is the preferred plastics material. Additional layers of reinforcing wires may be included if required and it is preferred that all wire be pretreated by e.g. shot blasting to improve adherence to the plastics material.