Various options available for centerlines. Various options that are available for centerlines. If you want to customize your towlines in some way just call or email us to discuss what would work best. Custom lengths. Rope centerlines with/without cable in the center. Reflective rope with/without cable in the center. Black coated centerlines with swagged loops on each end for attaching tugs and necklines. Black coated centerlines with swagged loops on each end with plastic blocks that swivel for attaching tugs and necklines.