Design and Strength Assessment of an Ice-Class Propeller Based on Ice-Resistance Matching and Rule-Based Ice Loads

An integrated design and strength-assessment method is developed for high ice-class propellers operating under low-speed, high-thrust icebreaking conditions. Icebreaking resistance predicted by the Lindqvist method is used to determine the propulsion demand and guide propeller-scale matching. The first-stage redesign retains the original 5.25 m propeller diameter as a retrofit constraint but exhibits significant hydrodynamic deterioration under heavily loaded behind-hull cavitating conditions. The diameter constraint is therefore relaxed, and a series-chart-based scale-rematching procedure using a reference thrust coefficient of KT ≈ 0.19 gives a redesigned diameter of 6.0 m. Its structural strength is evaluated under five rule-based ice-loading cases using finite-element analysis. The governing case produces a maximum equivalent stress of 249.68 MPa, a maximum displacement of 16.89 mm, and a safety factor of 1.63, exceeding the required value of 1.3. The results highlight the importance of coupling overall scale matching, hydrodynamic design, and ice-load strength assessment in high ice-class propeller design.