Power increase and propulsive characteristics in regular head waves of KVLCC2 using model tests

This paper employs experimental methods to predict speed-power-rpm relationship along with resistance and propulsion characteristics in regular head waves with varying wave lengths and steepness ratios. The objective ship is KVLCC2. The resistance and self-propulsion tests in calm water and in waves have been conducted. The self-propulsion point in waves changes to increase propeller revolution, thrust and torque with wave steepness. The added propeller revolution, thrust, torque and delivered power due to waves increase with wave steepness, and are not simply proportional to the square of the wave amplitude, which are similar tendencies to the added resistance. The thrust deduction and wake fraction, propeller advance coefficient, hull, propeller-open-water, relative rotative and propulsive efficiencies due to waves decrease with wave steepness. The effects of ship speed and delivered power in waves on the propulsive performances have been looked into. The wave conditions are the regular head waves of λ/LPP = 0.6 and 1.0 with three wave steepness ratios at three ship speeds of 13.5, 14.5 and 15.5 knots (design speed). In the case of λ/LPP = 0.6 at design speed, two more wave steepness ratios have been used. •Resistance and self-propulsion model tests for KVLCC2 in calm-water and waves.•Experimental estimation for the power increase in waves based on self-propulsion tests.•Effect of waves on propulsive characteristics is investigated in detail.•This study can be regarded as a basis to compare various prediction methods for power increase in waves.