An approximate power prediction method

In a recent publication a statistical method was presented for the determination of the required propulsive power at the initial design stage of a ship. This method was developed through a regression analysis of random model experiments and full-scale data, available at the Netherlands Ship Model Basin. Because the accuracy of the method was reported to be insufficient when unconventional combinations 'of main parameters were used, an attempt was made to extend
the method by adjusting the original numerical prediction model to test data obtained in some specific cases. This adaptation of the method has resulted into a set of prediction formulae with a wider range of application. Nevertheless, it should be noticed that the given modifications have a tentative character only, because the adjustments are based on a small number of experiments. In any case, the application is limited to hull forms resembling the average ship described by the main dimensions and form coefficients used in the method.
The extension of the method was focussed on improving the power prediction of high-block ships with low LIB-ratios and of slender naval ships with a complex appendage arrangement and immersed transom sterns.
Some parts of this study were carried out in the scope of the NSMB Co-operative Research programme. The adaptation of the method to' naval ships was carried out in a research study for the Royal Netherlands Navy. Permission to publish results of these studies is gratefully acknowledged.