This paper investigates the utilization of a swarm of autonomous tug boats to manipulate an unactuated vessel (i.e., barge or disabled vessel). Specifically the objective is to design a control strategy for each craft such that the combined effort of the swarm manipulates the unactuated vessel into a desired position and orientation under the constraints that the tugs can only exert a pushing force. The control scheme is verified through simulation. In addition, a preliminary control experiment was conducted on a custom built experimental teststand at the U.S. Naval Academy.