A tugboat (tug) is a boat that maneuvers vessels by pushing or towing them. Tugs move vessels that either should not move themselves, such as ships in a crowded harbor or a narrow canal, or those that cannot move by themselves, such as barges and disabled ships. Tugboats are powerful for their size and strongly built. Betsy is a tug located in the harbor in Woods Hole, Massachusetts. Faber-Castell Pitt pens in a Stillman and Birn Alpha Sketchbook.