Some Topics for Estimation of Bilge Keel Component of Roll Damping

In this paper, two topics of roll damping estimation are introduced. In these topics, bilge-keel component of roll damping is focused, because this component is generally most part of viscous roll damping. First topic is the bilge-keel component of roll damping under shallow draft and large amplitude roll motion, and an estimation method of the draft effects based on Ikeda’s method is proposed. Second topic is the bilge-keel component of roll damping under transitional and non-periodic rolling, an estimation method for time-domain simulation based on Ikeda’s method is introduced and its estimated results are compared with measured results of roll damping in irregular forced rolling.