A relatively lightweight tarping system for use with trailers or other open top containers includes first and second spaced frame members and an elongated flexible member such as a cable or chain connected to and extending therebetween. A tarpaulin may be mounted thereon so that the frame members, flexible member and tarpaulin are pivotable between a covered position atop the open top container and an uncovered position. A four-bar linkage is preferably used in combination with a rotational drive mechanism to provide various advantages in rotating the tarpaulin assembly between the covered and uncovered positions. A width adjustment mechanism is provided to provide usage with trailers or other open top containers of different widths. An improved seal is provided between the tarpaulin and container.