A method of analysing voyage data¹

Article type: Research Article

Authors: Clements, R.E.

Note: [1] Paper read before the North East Coast Institution of Engineers and Shipbuilders on the 25th of January, 1957.

Abstract: This paper describes a method of analysing service-performance data devised at The British Shipbuilding Research Association, by means of which it is possible to estimate the effect of weather and deterioration of the hull and propeller surface on the shaft horsepower necessary to maintain a given speed. A method of multiple-regression analysis is used to obtain the separate effects of adverse weather, and of fouling. It is shown how a suitable weather scale has been evolved by which it is possible to estimate the performance of a vessel in unrestricted waters knowing only the wind strength and direction. A method of estimating propeller efficiency in service is also described, and it is shown how this can be used to estimate the efficiency under most conditions likely to be encountered in service. By extending the analysis it is possible to estimate the thrust necessary to maintain a given speed under any conditions of weather or of fouling. In the present work, however, the thrust analysis has been restricted to comparisons between the thrust for a given speed on trial and the thrust for the same speed at the start of the maiden voyage and immediately after each subsequent drydocking. A numerical example is included and the results obtained from the analysis of voyage records of eight vessels are summarized.

DOI: 10.3233/ISP-1958-55001

Journal: International Shipbuilding Progress, vol. 5, no. 50, pp. 453-471, 1958