In practice, estimations of the navigating resistances of the ships designed for Arctic Shipping Routes are of great importance. Snow cover is generally the concomitant circumstance for natural sea ice and the ice breaking process is supposed to behave differently when snow is involved in. Thus, giving a reasonable estimation of ice resistance in snow covered situation is an essential requirement in fitting the operative philosophy. Equipped with load cell and tactile sensor, two comparative series of model tests (normal level ice and snow covered ice) were performed for a new designed icebreaker in the Ice Engineering Laboratory of Tianjin University. It is found that the presence of snow cover influences the ice cusp pattern and increases the ice resistance. The measured results are compared with the experimental estimation of Lindqvist method. Some important discussions are also made in the paper.


Ice-going vessels play important role in cold region. For guiding the design of ice-going vessels, ice class rules have been established on operative and safety concerns. As Kim et al. (2005) and Su et al. (2010) described, a typical operating scenario of interest for an ice region would require the ship to maintain a reasonable speed in the level ice of a certain thickness, and to be assured of making progress in much thicker ice. In practice, the ship must also be able to operate in snow covered ice, and to transit certain ridge and rubble configurations. Giving a reasonable estimation of ice resistance in such scenarios is the most basic and important requirement in fitting the operative philosophy.

In early design of an ice class vessel, ice resistance is always estimated by empirical or semi-empirical formulas. Validation of the design has to be examined in model tests because the available CFD-methods for ice resistance prediction are not sufficiently reliable to give a valuable contribution to the design process (Myland and Ehlers, 2014). During the model tests, ice thickness-ship velocity curve (h-v curve) is usually determined based on the measurement and analyze of the ice resistance. Ice resistance is dominated by the breaking, turning, submerging and sliding processes of ice while the vessel is navigating in level ice, e.g. Enkvist (1979), and Lindqvist (1989). The actual behaviors of these processes are depending on the mechanical properties of ice (i.e. isotropism or un-isotropism, strength, elastic modulus and friction) and ice conditions (i.e. thickness, drift velocity), as well as the geometric characteristics of the ship hull and the navigating speed.

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