Possibilities of representing the ship-tug cooperation in the free model tests

Model tests of ship manoeuvring in ports and in other restricted waters require the tug forces and moments to be taken into account. As the additional tug forceRhol can be relatively easily allowed for with reasonable approximation in a computer simulation system, the free model tests require more complicated methods. This paper contains a review of the methods used in the Experimental Centre in Ilawa and then in the Foundation for Safety of Navigation and Environment Protection in order to represent the ship-tug cooperation in the free model tests