Abstract: In order to forecast risk prospect of ship carrying liquefiable cargoes, the quantification of risk estimation in the process of ship safety operation was studied by HMM. The factors influencing ship transportation risk of liquefiable cargoes were identified, and an estimation structure model was built. The relevance of the variables was described by HMM. The model parameters were determined according to the questionnaire survey data and Baum-Welch algorithm. Voyage information was combined with forward algorithm and risk criterion to describe the risk transient and prospect. The sensitivity test of voyage risk estimation in multi-scene was carried out to verify the effectiveness of the model. The results indicate that liquefiable cargo has a big influence on the navigation risk in the pre-stage of the voyage, whose influence degree is 1.49, and the environmental deterioration has a huge impact on the risk in the post-stage, whose influence degree is as high as 1.65.

Key words: marine transportation, liquefiable solid bulk cargoes, hidden Markov model(HMM), operation safety risk, estimation