Tugboat, also called tug, is a small, powerful boat that maneuvers large vessels. Tugs that are used in harbors can tow large ocean liners or freighters and aid all types of vessels in entering or leaving their anchoring places. They can tow from the front or side, or push from the back. Tugs measure from 65 to more than 250 feet (20 to 76 meters) long. They are driven by engines with 2,000 to 22,000 horsepower (1,500 to 16,400 kilowatts). The largest tugboats are the oceangoing tugs, which rescue or assist ships at sea. Tugs used on inland lakes and rivers tow or push long lines of barges loaded with heavy cargoes. Modern tugs can push 40 or more barges at once.
