FUNDAMENTAL STUDY ON SHIP LIFE

Ship life depends on many factors. The factors will be divided into three groups, the law of nature, performance and economy. The laws of nature are mainly fatigue and corrosion which reduce the retained structural toughness in aged ships. The performance factors of social impact will sometimes act key point. For example, marine pollution has a great influence on types of ships. In economy factors, investment and its recovery are basic ones that should be analyzed, and cost sensitivity of each of the factors should be analyzed on the point of effect on life. And some investigations show low finantial merit in ship life extention. The authors investigated the factors for proper ship life in basic and fundamental aspect, and confirmed that it should be taken heads to link the factors together. The points to be cleared in engineering point of view are the properties of corroded plates, and some results show very low fatigue strength and fracture toughness that warn low strength redundancy of aged ships.