An electrically powered hoisting system is operated by seating a line attached to the load to be hoisted in a groove formed between two sheave components and activating the electrical drive motor to rotate the sheave assembly. Voltage for the electrical drive motor is provided by an on-board 12 volt battery and voltage to the drive motor is controlled by means of a switch device. The groove formed by the sheave components has a resilient gripping surface that provides a firm line gripping action and hands-free and self-tailing operation. A davit, davit mounting brackets, and a flexible mounting assembly for mounting the powerhead assembly to a support are also disclosed.