A fastener system for securing a grating to an underlying structural support member when the grating experiences extremely high wave pressures. The fastening system includes elongated generally L-shaped connectors for fastening the longitudinal edges of grating sheets to structural members and plate fasteners in a wave zone area of the platform. The plate fasteners have a top plate for mounting on an upper surface of the grating sheets, a bottom plate for attaching to the structural members in a laterally extending direction for supporting the grating sheet and bolt assemblies for clamping the top and bottom plates together in order to secure the grating sheets to the structural members. A combination of the elongated L-shaped connectors and the plate fasteners provide fastening support for the gratings sheets so as to resist vertical and horizontal wave pressures when secured to the supporting members.