Abstract: A cover deployment system includes a flexible cover configured to span an open top of a trailer, the trailer having a front end, a rear end, and longitudinally extending side walls extending therebetween, bow assemblies connected to the cover, and a cable system including a pair of cables, an electric actuator, a manual actuator, and a differential. The cables extend longitudinally along the longitudinal side of the trailer. Each cable defines a loop supported by a pulley at the front end of the trailer and a pulley at the rear end of the trailer. The remaining bow assemblies are movably attached to the cables. The electric actuator and the manual actuator are operatively connected to a differential positioned between the electric actuator, the manual actuator, and the pulley. The differential is connected and rotates a pulley to move the cables, thereby moving the cover between closed and open positions.