Ships encounter various ice conditions such as level ice, ridged ice, floe ice and ice-clogged channel. Various models have been developed so far for the prediction of ice resistance in various ice conditions. The authors proposed the hybrid model of resistance prediction of ships navigating in floe ice including small ice floes, ice-clogged channel and a large ice floe. This model consists of two existing models, i.e. Kashitelijan-Poznjok-Ryblin and Lindqvist model. The former model gives the ice load at the limit momentum condition and can be fundamentally applied to the resistance prediction of ships in small ice floes. The latter model is originally developed for resistance prediction in level ice. It gives the ice load at the limit stress condition and can be applied to the prediction in a large ice floe. Resistance in floe ice can be determined as the smaller resistance predicted by either of two models. The former model is also applicable to the resistance prediction in ice-clogged channel by taking the influence of the restricted ice area into account. The accuracy of each model was validated through comparisons with the model-scale experiments conducted at the ice model basin of the National Maritime Research Institute. Validation study was also conducted through comparisons with the full-scale thrust measurements in the southern part of the Sea of Okhotsk, Japan. It is found that the proposed model is capable of predicting the resistance in floe ice of various sizes and concentrations with reasonable accuracy. This model is applicable to the transit simulation along the Northern Sea Route.
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