On the safety level of the SOLAS 2009 damage stability rules for RoPax vessels

Abstract

Heading The new probabilistic damage stability rules in SOLAS 2009 and their impact on the safety of the ship subdivi- sion design have been widely discussed. Especially the safety level of RoPax designs are considered for further investigations. This paper describes a methodology to compare the safety provided by different damage stability regulations for a certain ship design. The determination of the dam- age cases probabilities are based on a Monte Carlo si- mulation for the damage distributions. The damage cube itself is modeled by distribution functions retrieved from statistics based on the HARDER project. This gives a very elegant, fast and direct approach of damage calculations. Together with the calculation of the survi- vability of all damage cases, this allows to identify and compare the safety level indices of different damage stability standards. The method has been used in the "EMSA Study on Damage Stability of ROPAX vessels". The theory of the simulation methodology and some extracts of the results of the EMSA study will be presented in the following. It has been shown in the study that for the investigated RoPax designs the new SOLAS 2009 rules are less stringent than the old, deterministic rules according to the Stockholm agreement. This means that especially the old water-on-deck requirement results in more se- vere designs and that the required index of the new damage rules is too low for the investigated RoPax