A fastener includes a self-locking pin washer and at least one elongate projection mounted on the self-locking pin washer, where the self-locking pin washer is arranged to be a resistance fit to a projection mounted on a structure or vehicle. A method of fastening a panel to a substrate includes attaching a fastener to a projection of a substrate, wherein the fastener includes an elongate projection that is longer than the projection. The method further includes attaching a panel onto the elongate projection of the fastener.