A boat lift with hydraulically or mechanically actuated arms which self-installs a fitted three-dimensional boat cover on a powerboat. The control logic of the system allows for cover operation only when the lift is raised. A spring-tensioned roller keeps the cover tight and self-rolls the cover on the roller when the actuated arms are pivoted forward. The roller is hidden behind the boat in ‘cover-on’ position. A slip clutch prevents the torsion spring from being over tightened. The forward position of the roller is adjusted by adjusting the hydraulic cylinder length. The rearward position of the roller is adjusted by limiting the retracted position of the hydraulic cylinder. A non-hydraulic embodiment actuates the cover when the lift is operated.