Shinkichi Tanigaki

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.

Development of Multi-Connected Floating Body System

A multi-connected floating body system composed of many connected small-scale floating body units has a number of advantages with regard to construction and performance. To realize the multi-connected floating body system, a new type of mechanical connecting device was developed. It is composed of multi-degrees of freedom connecting mechanism and restricting mechanism to control a restricting condition between floating body units, and its effectiveness was confirmed by model basin test in waves. Next, friction and wear tests in the seawater environment led to the discovery of suitable materials for oscillatory sliding parts in multi-degrees of freedom connecting mechanism. Finally, a field test performed for two floating body units connected by use of the mechanical connecting device proved that the developed mechanical connecting device was of practical use.Copyright