Hassan Ghassemi - Assistant Professor, Faculty of Marine Technology, Amirkabir University of Technology, Tehran, Iran
Roya shademani - MSC student of naval architect, Amirkabir University of Technology, Tehran, Iran

This paper describes a contra-rotating propeller (CRP) system to calculate the hydrodynamic characteristics and then obtain the optimum operational condition to install on two different large bulk carrier and VLCC. The method is based on boundary element method (BEM) to obtain the hydrodynamic performance of any complicated configuration such as CRP system, and then the optimum propeller data is obtained by the systematical method at the design condition. We prepared a software package code, namely SPD, which has model mesh generation, solver and numerical output results. The comparison of the propulsive performance was made between the propeller alone and CRP arrangement. Major finding include good agreement between predictions using the modified code and experimental data for both ships.

CRP, Boundary Element Method, Optimum Efficiency