Small tug ship in port, Gdansk / Poland. Shipyard in the background.
"A tug (tugboat or towboat) is a type of vessel that maneuvers other vessels by pushing or pulling them either by direct contact or by means of a tow line. Tugs typically move vessels that either are restricted in their ability to maneuver on their own, such as ships in a crowded harbor or a narrow canal, or those that cannot move by themselves, such as barges, disabled ships, log rafts, or oil platforms."Wikipedia, The Free Encyclopedia, "Tugboat", https://en.wikipedia.org/wiki/Tugboat
