Disclosed is a tugboat 1 for assisting a marine vessel 2 to manoeuvre. The tugboat 1 comprises a hull 11 having a perimeter P. The tugboat 1 also comprises a line handling system 10 comprising a line guide mechanism 100. The line guide mechanism 100 is movable relative to the hull 11 to an operation position, at which the line guide mechanism 100 is for guiding movement of a portion of a line 13 of the tugboat 1 towards a predetermined region R of the perimeter P.