Assessment of the technical safe limit speed of a non-ice-strengthened naval vessel with representative and alternative side shell designs in ice-infested waters

Abstract

ABSTRACT Sailing in ice-infested waters has become more relevant for the Royal Netherlands Navy (RNLN). A method is developed to determine the technical safe speed for a single ice floe impact with a typical non-ice strengthened naval vessel. A representative ice floe impact load scenario is applied to three structural arrangements for the side shell structure: a reference design and two alternative Lean Duplex designs. Practical visual and structural acceptance criteria are defined. The proposed changes to the structural layout and the material will improve the ability to resist floe impacts at higher sailing speeds. The first exceedance of a visual criterion is improved from 1 m/s to 2 m/s. The more severe structural criterion is not exceeded at all, while this was the case for the reference design (at 2 m/s). Nevertheless, permanent deformations, are to be expected when these non-ice strengthened ships are operating in ice-infested waters.