Mohammad Reza Golbahar

Surface piercing propellers are widely employed in high-speed crafts due to having many favorable features. These propellers operate at both submerged and semisubmerged states. In submerged state, to enhance the propeller hydrodynamic performance, the blades are usually manipulated through artificial ventilation by adding the air duct which is located at the propeller suction side. In current study, a 5-blade propeller proficiency has been studied under different operational conditions of 16 m catamaran vessel experimentally, the sea trial, and numerically using Computational Fluid Dynamics (CFD). The propeller behavior has been investigated under four sea trials while the propeller torque has been sampled at different engine states and vessel speed. The numerical study through CFD has been done to analyze the propeller behavior under different conditions, submerged and semi-submerged states. The numerical results have been validated by experimental observations. The propeller proficiency has been studied in two vessel motion stages which are preplaning and post-planing. The results depict that the maximum torque is observed in submerged state at the last step of pre-planing mode while the engine speed is 2300 rpm. The propeller torque is reduced 10 to 16% at 2500 rpm in post-planning stage. In submerged state, the propeller proficiency is negligible at pre-planing mode.