It is said in general that all ships degrade gradually their facilities as the time passes. The authors tried to obtain the aging characteristics of ships quantatively as possible as they could. Some of the results are shown as follows after processing the data from engine abstracted log-books of the gigantic tankers with steam turbine engine statistically: - F.O. consumption (constant speed) increases at the rate of 2〜7% a year and F.O. consumption (constant revolution of engine) 2〜5%, and ship's speed decreases 0.5〜2%, propeller revolution 0.5〜1.5, Admiralty number (speed) 2〜5.5, and Admiralty number (revolution) 1.5〜4%.
