Summary: | Speed data for three fast North Atlantic ships each collected over three week periods, plus eight months data extracted from the log books of a fourth ship, has been analysed using multiple regression techniques. The speeds through the water have been successfully corrected for systematic errors in the ships' logs caused by varying draught, weather conditions, and time drift. Significant speed variations with time, wave height, wind speed, displacement and sea temperature have been found. Empirical formulae for estimating the ships' speeds are given. A simple method of correlating the speed loss of ships in bad weather with their speed-power curves is proposed. Several applications of ship speed analysis results, such as weather routeing, are discussed.
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