*Article* **Effect of Propeller Cup on the Reduction of Fuel Consumption in Realistic Weather Conditions**

**Mina Tadros 1,2,\*, Roberto Vettor 1, Manuel Ventura <sup>1</sup> and C. Guedes Soares <sup>1</sup>**


**Abstract:** This paper presents the effect of a propeller cup on the propeller cavitation and the fuel consumption of a bulk carrier in both calm water and different weather conditions towards improving the energy efficiency of the ship and reducing the level of emissions in terms of design and operation. Based on the propeller optimization model, previously developed that couples NavCad and a Matlab code to select the geometry and the operating point of the propeller at the engine operating point with minimum fuel consumption, the optimized propeller performance is evaluated for different percentages of the cup; light, medium and heavy and compared with the performance of the propeller without a cup in both calm water and several sea states. By evaluating the cavitation criteria, it is concluded that increasing the percentage of cupping reduces the occurrence of cavitation based on the Keller and Burrill methods; moreover, the fuel consumption is reduced by up to 5.4% and 6.6% at the propeller with a higher percentage of cup compared with the uncapped propeller in calm water and among the ship route, respectively.

**Keywords:** bulk carrier; propeller cup; fuel consumption; decarbonization; weather condition; cavitation
