5. A Study of Components of Wind and Current Loads on Semisubmersibles :
For analysis of intact and damage stability of semisubmersible type rig, it is important to estimate the magnitude of steady environmental forces such as wind and current forces and moments. Since it is difficult to get the theoretical calculations of these forces and the test techniques need special apparatus, only few researches have been done in these fields. In this paper an attempt to clarify the contribution of various elements of semisubmersible to total force and moment using 1/100 and 1/150 scale test models is made, and the validity of wind tunnel tests in a water channel with wind tunnel facility is discussed. Although the difficulty to simulate the boundary layer on water surface exists, the wind velocity profile required by rules of classification societies was done with success and 6 component forces and moments were measured in this environmental condition. In order to obtain the total force and overturning moment the towing tank test of under water part was carried out, and lift effect on lower hull was observes. Finally the comparison of experimental results and the corresponding calculations obtained from ABS and DnV rules was done and the accuracy of these calculation methods is discussed.
- Naval architecture and ocean engineering
Naval architecture and ocean engineering 23, 53-65, 1985
the Society of Naval Architects of Japan