An assembly includes a hoist or a winch, a cable, and a fleet angle sensor. The fleet angle sensor includes a frame disposed around an opening and the cable extends through the opening. A first photodetector with multiple light-receiving zones is mounted on the frame. A first light source is mounted on the frame opposite the first photodetector. A shield device is under the frame and includes a shield frame and a cover. The shield frame is around the cable and the cover extends from the shield frame toward the cable, with the cable extending through the cover.