An arrangement of five supporting elements together with appropriate T-connectors and a four-way connector are employed to provide a device for loading one or more watercraft onto the top of a vehicle. The device is employable with conventional roof rack and kayak cradling structures. The arrangement includes a rotatable mast and boom which may be swung from one side of the vehicle to the other so that hoisting capabilities are available on either side of the vehicle so that multiple watercraft may be easily loaded onto the vehicle with minimal effort by one person.