tugboat (tug) is a boat that maneuvers vessels by
pushing or towing them.
Tugs move vessels that should not move themselves alone,
such as ships in a crowded harbor a narrow canal, or those that cannot move
themselves, such as barges, disabled ships, or oil platforms.
Tugboats are powerful for their size and strongly built, some
Some tugboats serve as icebreakers or salvage boats. Early tugboats had
steam engines; today diesel engines are used.