ABSTRACT

The paper puts forward a theoretical capsizing probability calculation model that is suitable for the preliminary design stage. Based on the risk-based design concepts, the capsizing probability calculation model is nested into the traditional ship form optimization process. Thus, the hull form modification model based on capsizing risk forecasting is obtained. In this paper, the cruise ship of the Yangtze River trunk line is considered as a parent ship. Ship form parameters are the main optimization objects that are constrained within a certain range. The maximum roll angle and capsizing probability in regular waves are used as objective functions. Optimization decision is made between design factors such as intact stability indicators and economic indicators. Therefore, the ship's capsizing rick can be effectively evaluated and forecasted during the preliminary design stage.

INTRODUCTION

In recent years, cruise tourism has become more and more popular. Taking the Yangtze River Basin as an example, by 2018, more than 40 luxury cruise ships with four-star or above will have a combined capacity of about 14,000 passengers and a total reception capacity of about 700,000 passengers per year(Feng, 2018). As the cruise ship of the inland river is developing towards luxury and large scale, ensuring cruise's safety performance is becoming a topic of general interest. For cruise ships, the intact stability is especially important. Once the ship is capsized, it will cause heavy losses to the lives and property of the passengers. Unlike the small ferry, the inland river luxury tourist cruise ship has large dimensions, and has the characteristics of shallow draft, developed superstructure and high center of gravity. When encountering wind and waves, it is prone to occur large roll motion or even overturning accidents. Over the years, people have been persistently exploring the intact stability criteria that can guarantee the safety of ships. Huang et al. (2001) studied the calculation of ship capsizing probability under the combined action of crosswind and wave, and solved the equivalent linearized differential equation of roll motion. Liu (2004) studied the ship stability under the combined action of crosswind, beam wave and wind-wave, simplified the non-linear roll equation by harmonic balance method and multi-scale method, and derived the higher-order equation of roll angle and encounter frequency. Hoon (2006) studied the calculation of ship capsizing probability by solving the joint probability density function. Arena et al. (2013) considered the maximum roll motion of a ship in confused sea waves, and showed that a reliable estimate of the maximum roll motion is found considering the ship response to an approximate deterministic representation of an appropriately large and adequately rich(frequency-wise)load.

This content is only available via PDF.
You can access this article if you purchase or spend a download.