Maki, AtsuoAtsuoMakiDostal, LeoLeoDostalMaruyama, YuukiYuukiMaruyamaSakai, MasahiroMasahiroSakaiSugimoto, KeiKeiSugimotoFukumoto, YusukeYusukeFukumotoUmeda, NaoyaNaoyaUmeda2020-10-092020-10-092021-09Journal of Marine Science and Technology 26 (3): 828-834 (2021-11)http://hdl.handle.net/11420/7539The prevention of excessive roll acceleration is one of the fundamental requirements of an oceangoing vessel at sea. In this paper, aiming at this requirement, we propose a new theoretical method for calculating roll angular acceleration, called “PDF line integral method.”. This paper presents the derivation of this method and a numerical comparison with Monte Carlo simulation (MCS) results; also, its validity is shown. Although the utilized GZ curve (restoring curve) exhibits strong asymmetricity, the proposed method can provide for such a condition. With only the information of roll and roll rate joint probability density function (PDF), this method can approximately calculate the roll angular acceleration, which is a high-order differential property. In addition, a relatively good agreement is achieved between the theory and MCS results.en0948-428020213828834Excessive accelerationIrregular beam SeasPDF line integral methodRoll angular accelerationJournal Article10.1007/s00773-020-00770-1Other