Survivability of ships at sea: A proposed model to account for human factors in a safety critical system

Most serious accidents at sea are caused by minor incidents that escalated into an uncontrolled situation. This study is aiming to develop a model to investigate the likelihood of fatal accidents, given that a critical incident has already occurred. The focus of the study is on the human factors by adopting a hardware reliability perspective. The vessel is considered as a safety-critical system to be protected by several barriers. The crew role is modelled as active barriers and distinguishing between different functions: perception, decision and action. A Markov approach is utilized to model different situations on the vessel. A mathematical model to estimate the probability of failure in an emergency situation is formulated. A new parameter is defined for the survivability of a vessel, given that a critical incident has taken place. The methods were applied to examine ship-platform collisions cases and the results show strong benefits for diagnosing and evaluating accidents from the human factors perspectives as well as for training purposes