This paper concerns results of model tests and full scale measurements of the propeller designed for inland ship (749 GT chemical tanker) aiming 1% increase of propulsive efficiency comparing with 1st retrofit small blade area NHV (Non Hub-Vortex)propeller.It was shown in the 1st report that the 1st retrofit propeller, of which blade area was decreased by 20% from the original propeller, reduced 4% of the engine output without any problem of the ship vibration and cavitation erosion.SBA-NHV propeller (Smallest Blade Area NHV propeller), of which the diameter was increased by 3.3% and the blade area was decreased by 10% from the 1st retrofit propeller, was designed and towing tank tests (propeller open water test and self propulsion test) and cavitation tests (cavitation observation, erosion paint test and fluctuating pressure measurement) were carried out. The model test results showed that the propulsive efficiency of the SBA-NHV propeller is about 1.5% higher than that of the 1st retrofit propeller and the risk of cavitation erosion and the fluctuating pressure of both propellers are almost equivalent.Finally, sea trial test of 749 GT chemical tanker was performed with the SBA-NHV propeller which was manufactured as the second retrofit propeller. The sea trial test results demonstrated about 2.5% deduction of engine output without any problem of the ship vibration comparing with the 1st retrofit propeller. And it was confirmed that the turning and stopping abilities of the SBA-NHV propeller were equivalent and a little worse respectively comparing with those of the original propeller.
