A Study on the Stabilizing Method of Semisubmersible Platform with a Large List in Waves

Abstract

There have been many studies concerning the stability problem of a semisubmersible platform since several tragic accidents of it had happened. Particularly it is important to stabilize the damage condition of semisubmersible platform in rough sea conditions from the safety viewpoint of a floating structure. So far, however, there have been very few study concerning it above mentioned. In this paper, an attempt to stabilize the damage condition of semisubmersible platform with a large list is made. A time domain simulation is developed to predict the motions of a semisubmersible platform in rough seas, in which the dynamic balance of the platform may vary with time due to the adjusting the ballast water in the lowerhull. Comparing with the experimental results of the platform with a large list in waves, it is made clear that the computer simulation fairly well estimate the dynamic behavior of the platform. In order to stabilize the platform with a large list, the adjusting the ballast water by using the pumping system is proposed. It is made clear from the time domain simulation that this method is very useful for stabilizing the damage condition of the platform with a large list in waves. Finally an unstable rolling oscillation of the platform with a large list angle is discussed.