An approximate power prediction method

In an earlier 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 he insufficient when unconventional combinations of main parameters were used, an attempt is made in the present article 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 in a set of prediction formulae with a wider range of application. Nevertheless, it is pointed out 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 focused on improving the power prediction for high-block ships with low L/B ratios, and for slender naval ships with complex appendage arrangements and immersed transom sterns.