A COUNTERMEASURE AGAINST LOW FREQUENCY MOTIONS OF A MOORED SHIP USING SHIELDING STRUCTURE

This paper shows a countermeasure against low frequency motions of a moored ship. It is difficult to decrease the low frequency surge motions of the ship moored by fiber ropes, because breakwater cannot prevent the entrance of low frequency components of ocean waves. Furthermore the very small damping force of surge motion interferes reducing resonance motions in the low frequency range. The shielding structure, which is close to the weather side of the ship, is prevent the flow due to the low frequency waves so it decreases the wave exciting force. Then the effect of the shielding structure is confirmed by the tank tests. Moreover, the effect of the structure, which consists of flame structure and membrane, is also confirmed. This shielding structure effectively decreases the low frequency surge motions of a moored ship.