Chain-driven system is also applied to side rolling hatch cover system. The operating chains, which are guided along both of the transverse coamings are corrected cross- wise to the arms of both panels giving simultaneous operation of the panels. One-sided type and two-sided type are driven by a low speed hydraulic motor with a planetary gear and is mounted on the ships deck at one side between the stowing ramps. Cleating devices shall be of either manual quick acting type or auto hydraulic operating type.