Calculation of Added Resistance in Head Sea Waves by Means of a Simplified Formula

The formula for the theoretical prediction of the added resistance in head sea waves is simplified by the assumption that the frequency of encounter is not small.Computations of the added resistance for the Series 60 models by means of the simplified formula are compared with computation by the original formula and results of experiments.The results of the new formula show a considerable improvement in the agreement with the measured results.