The safety aspects of ship handing have become increasingly important recently, due to the changes in sea transportation. These are characterizes by larger units, increased traffic density on sea lane, sea transport of dangerous cargo, etc. In addition, as a economic aspect of ship handing, it has obtained an increased attention in connection with port development and consideration of allowable ship size for existing ports. One method for evaluation of maneuvering problems is simulation on a computer by means of a mathematical model of the ship maneuvering motion. The present report describes the elements of a mathematical model for ship maneuvering and gives some results of maneuvering predictions through the simulation.