A tugboat or towboat is a type of boat that maneuvers other vessels by pushing or pulling them. This is done either by direct contact or by means of a tow line. Tugboats typically move vessels that are restricted in their ability to maneuver on their own, such as ships in a crowded harbor or a narrow canal, Also, vessels that cannot move by themselves, such as barges, disabled ships, log rafts, or oil platforms. 