The author has investigated on the effect of elastic property of rope to the amount of the movement of ship and to the tension of the rope, in some cases of mooring the ship or towing the ship by tug. The results are as follows: -1) In case of mooring, the elastic properties of ropes do not affect to the tensions, so it is advisable to use wire ropes because the amount of the movement of ship becomes smaller. 2) But when heaving and or pitching motions, or horizontal movements of a ship are caused by wave, swell, surge etc., the elastic properties of ropes affect to the tensions, so it is better to use fibre ropes. 3) In case of towing a ship by tug or the berthing prosedure of a ship, and when tug boat or the ship having initial speed (these are nomal cases), the elastic properties of ropes affect on the tensions of ropes, so it is better to use fibre ropes.