Application of a Backward Tip Rake Propeller to Actual Ships

This paper discusses the effectiveness of a backward tip rake (BTR) for a marine propeller on a propeller open water efficiency, cavitation erosion and a pressure fluctuation based on the results of RANS analysis, model tests and actual ship tests.The BTR was applied to a small blade area propeller which was expected the pressure fluctuations increase. RANS analysis and model test results showed that there was no loss in the propeller open water efficiency, and no serious risk in cavitation erosion and pressure vibrations. Then actual ship test results showed that hull vibration speed was kept within the permissible range and there was no cavitation erosion indication. In addition, when not adopting the BTR, RANS analysis results indicated that the pressure fluctuations increased comparing to that of BTR propellers. The effectiveness of BTR propellers was confirmed from these results.