engleski

EVALUATION OF RESISTANCE OF PLANING HULLS IN SMOOTH WATER

The aim of this paper is evaluation of the total resistance of planing forms with prismatic hull. Computer code has been developed to estimate the total resistance in the planing and preplaning range, which allows the designer to predict the total resistance in the preliminary design phase. Savitsky method is used to evaluate the total resistance in the preplaning and planing speed range, and Savitsky-Brown method for preplaning speed range. Code is tested on Series 62 models because of available experimental data from towing tank tests conducted at the Brodarski Institute in Zagreb. The total resistance obtained by the program code is compared with the measurements of the total resistance. From the obtained results it is evident that the Savitsky method is not suitable for resistance evaluation in the range of the volume Froude number because the deviations in results may be up to 45%, while for the higher Froude number range gives satisfactory agreement with the measured values with a maximum deviation of up to 20 %. For the low values of the volume Froude number the application of Savitsky-Brown method is recommended, which gives deviations of up to 10%.

resistance; planing; preplaning

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