A system includes two or more lifting devices attached to a structure each lifting device having a drum rotated by a motor to draw in or let out a line from the drum. The drum includes a groove formed in an outer surface thereof to accommodate the line. In certain embodiments, each of the lifting devices are quickly and easily detachable from the structure by way of a flange and mounting bracket. The flange and mounting bracket have holes which are coaxially aligned. A pin or other fastener is used to join the flange and mounting bracket together. Two or more lifting devices may be connected to and moved along a mounting bracket.