Assessment of Excessive Acceleration of the IMO Second Generation Intact Stability Criteria for the Tanker

Abstract

Recently, the IMO (International Maritime Organization) has reviewed technical issues considering the second generation intact stability criteria in the design stage of ships. In this paper, the evaluation procedure for Lv1 (Level 1) and Lv2 (Level 2) was introduced by focusing on the excessive acceleration mode. Based on real ship data, the calculation process has been explained in detail to make it easy to understand. When the Lv1 criteria considering simple hydrostatic calculations are not satisfied, the computational results of the Lv2 criteria based on mathematical modeling and the hydrodynamics are presented. The relatively low ship roll periods and large changes in the hull shape in the vertical direction make the ships potentially vulnerable to excessive acceleration phenomena. Therefore, the minimum value of height KG that satisfies the stability criteria evaluation in consideration of loading conditions for actually navigating of the ship in the sea should be estimated and operated. In particular, roll damping coefficients using the Ikeda’s method, which are essential for Lv2 vulnerability calculation, were obtained and verified by comparing them with other ship results.

Keywords

• IMO second generation intact stability criteria
• excessive acceleration
• roll period
• roll damping coefficient