A golf club head is formed with a crown having an aperture with an arcuate rear edge and a forward edge that is substantially parallel to the striking face. The aperture is transected by an arcuate rib that extends from a region proximal the heel end of the crown to a region proximal the toe end of the crown and is concave toward the striking face. A pair of linear ribs extend radially outward from the arcuate rib to join the arcuate rib to a perimeter region of the crown. Openings formed in the aperture by the ribs are filled with an organic-composite material such as graphite epoxy.