An improved winch assembly adaptably configured for use with a new or existing lift structure suitably dedicated for short- and long-term storage of a recreational boat and related watercraft. The winch assembly comprises three drive assemblies housed and mounted within a chassis. The first drive assembly comprises a first plate sprocket and a pair of cable guards collectively mounted onto a cable hub to form a spool assembly for accepting and winding thereon a predetermined length of cabling. The second drive assembly comprises a stepped hub having three discrete cylindrical surfaces to form first and second annular walls for mounting thereagainst primary and secondary plate sprockets and an inner bore extending therethrough for receiving therein an intermediate axle having ends affixed to the chassis, wherein the primary plate sprocket is connectively coupled with the first plate sprocket by a drive chain. The third drive assembly comprises a motor hub mounted to the chassis by means of a mount plate and having primary and secondary cylindrical surfaces each of differing diameter to form an annular wall for mounting thereagainst a plate sprocket connectively coupled to the secondary plate sprocket by a motor drive chain and first and second elongate bores extending longitudinally through the primary and secondary cylindrical surfaces for receiving and housing therein an output shaft of either a 110/220- or 12/24-volt electric motor and an axle having a hex-shaped head positioned externally to the mount plate for manual turning of the drive assemblies in the event of the electric motor's failure, respectively.